WO2004109136A1

WO2004109136A1 - Drive couplers

Info

Publication number: WO2004109136A1
Application number: PCT/AU2004/000751
Authority: WO
Inventors: Boris Klaricic
Original assignee: Select Design Technologies Limited
Priority date: 2003-06-05
Filing date: 2004-06-07
Publication date: 2004-12-16
Also published as: AU2003902820A0

Abstract

A transmission uses a direct electric gearshift system in combination with a multi-cone clutch as a launch device enabling disconnection of drive during gear change. One example is a two shaft six-speed box having direct electric gear shift arrangement and single multi-cone launch comprising: a drive shaft 1 which contains a cluster of gears 2, 3, 4, 5, 6, 7 and 8 each gear having its own diameter. All gears on shaft 1 are formed to mesh with gears 2A, 3A, 4A, 5A, 6A, 7A, and 8A of the output shaft 9. Gears 4 and 5 on shaft 1 and gears 2A, 3A, 6A, 7A and 8A on shaft 9 are free rotating. The ends of shaft 1 and shaft 9 are supported on bearings 10, 11, 12 & 13 received by casing 14 and clutch housing 15. Shaft 1 with gears 2, 3, 4, 5, 6, 7 and 8; shaft 9 with gears 2A, 3A, 4A, 5A, 6A, 7A and 8A of Figure 1 and four gear selection devices 16 as shown in Figure 1 and 2 compose a technical assembly which, when in operation present six-speed automated manual transmission.

Description

DRIVE COUPLERS

FIELD OF INVENTION This invention relates, in general, to automated manual multi speed transmission, and has particular relation to transmission including an improved synchronizer and dog clutch for fast engagement of gears and multi-cone clutch employed as a launch device.

BACKGROUND OF INVENTION

In the automotive industry there has been a trend in recent years towards increased use of automated manual transmissions for improvement of motoring comfort and making cars easier to drive. The major task to automate a manual transmission was to shorten shift times between the gears. While there was a number of AMT transmissions put on the production lines the main point of criticism for these systems; the interruption in traction during the gear shift which is felt to be too long, still remains.

The length of the interruption in traction on vehicles in lower gears or on vehicles with high acceleration capacity has a major influence on the pitching motion. It has been recognized by the automotive industry that automated manual transmission apart from playing an important role in reduction of fuel consumption, exhaust emissions and simplified operation it also improves driving comfort and safety.

All modern automated manual gearboxes use synchronizer and dog clutch to shift gears. Development efforts are concentrating on the quality of gearshift linkage; the connection between the gear lever and gear selectors with the objective to make movements smaller, lighter and more precise.

Majority and maybe all of automated manual transmissions known to date are existing lay shaft arrangements maintaining conventional dog clutches, synchronizers, forks, rods, and associated components with the addition of three units to a conventional manual gearbox: a clutch servo unit, a gear selection servo unit and an electronic control unit taking care of engine speed and load, which coordinates clutch operation and gear selection accordingly. Because of this added external servo devices and related components the conventional manual transmissions become bigger, heavier and above all more complex and costlier to manufacture. The publicised shift times are about 150 ms (milliseconds). This has been recognised to be too slow to provide smooth gear change to the satisfaction of driver because the jerkiness of gear change is still evident. The automated manual transmission as depicted in this invention employs direct electric actuation system for fast synchronizer movement and dog clutch engagement.

In order to increase clutching capacity and provide a smooth launch a multi-cone clutch has been chosen to provide this important feature essential for automated manual transmission. Said synchroniser and dog clutch apparatus easily packages into the same or smaller space occupied by the conventional synchronizers and dog clutches.

The wet type multi-cone clutch is high energy density device requiring several times reduces actuation force for the same torque transmitted when compared with equivalent flat multi-plate clutch. The gear engaging apparatus and clutch operating system are based on known solenoid and plunger technology. Due to the quickness of direct electric system employed to engage gears the shift times can be low as much as 20 milliseconds because time to synchronize and engage dog clutch is direct function of electrical current going through solenoid coil and cross section area of the plunger. Thus for a given size of solenoid and plunger the shift times can be adjusted by varying the current.

The multi-cone clutch employed in this invention has been fully described in International Patent Application No PCT/AU01/01416 by the same inventor. Two examples of six-speed transmissions have been described in this paper; one employing single multi-cone clutch as launch device and second employing double multi-cone clutch as launch device. Transmission fitted with single multi-cone clutch requires torque interrupt for gear shifting. Transmission fitted with double multi-cone clutch provides full power shift system. The double clutch enables pre engagement of gears a feature, which takes more and more attention in automotive transmission applications.

The logical step, given the technology now available is to apply direct electric gear selection apparatus and to co-ordinate gear change with direct electric multi-cone clutch operation to create an alternative form of either torque interrupt or full power shift automated manual transmission.

SUMMARY OF THE INVENTION In one broad form the invention resides in a direct electric gearshift system in combination with a multi-cone clutch as a launch whereby gearshift times can be controlled to suit driver comfort and mode of drive.

One of the main objects of the present invention is to provide an improved form of synchronizer and dog clutch, more particularly, capacity for decreased shift times. Another object of the invention is to provide a form of high torque multi-cone clutch, more particular, capacity to vary launch times.

Another object of the invention is to provide an automated manual transmission that could closely be matched with the conventional automatic transmission in terms of gear change and driver comfort.

It is a further object of the invention to provide a transmission of low weight, comparatively low cost and optimal transmission effectiveness as well as improved fuel consumption and emissions.

In one aspect there is provided a single multi-cone clutch transmission for use in motor vehicle, comprising: a rotational input shaft supporting a set of fixed and free rotating gears which are meshed with corresponding gears on output shaft; a rotational output shaft supporting a set of fixed and free rotating gears which are meshed with corresponding gears on input shaft; a multi-cone launch clutch operable for establishing a releasable drive connection between engine and said input shaft; The single multi-cone clutch transmission preferably further comprises: . an electrically powered actuator controlling gradual engagement or disengagement of multi-cone clutch; an electrically powered actuators for controlling actuation of synchronizers and releasable coupling of dog clutches; The single multi-cone clutch transmission preferably further comprises: a synchronizer hub adapted to axially move on shaft for establishing a contact of its friction surfaces with a friction surfaces of free rotating gears to synchronize the rotary speed of said shaft to that of said free rotating gear; a dog clutch sleeve adapted to axially move on said synchronizer hub for establishing a releasable drive connection between drive and driven gear; a locating spring loaded pins placed therein in said synchronizer hub for ensuring neutral position of said hub when synchronization of the rotary speed between said free rotating gear and said shaft is accomplished; a locating spring loaded pins placed in said dog clutch sleeve for ensuring said dog clutch sleeve selectable position therein in the said hub; an electric solenoid coils carrier plate appropriately formed and fixed to box casing; a pair of solenoid coils for exerting a magnetic axial force on demand for moving said synchronizer hub and dog clutch sleeve. In another aspect there is provided a double multi-cone clutch transmission for otor vehicle, comprising; a rotational input shaft incorporating torque transmitting element of double multi- cone clutch; a first main shaft rotationally supporting a set of fixed drive gears which are meshed with corresponding driven gears on output shaft; a second main shaft rotationally supporting a set of free fixed drive gears which are meshed with corresponding gears on output shaft; an output shaft rotationally supporting a set of free rotating gears which are meshed with corresponding gears on first and second main shaft; a first multi-cone clutch torque transmitting elements operable for establishing drive connection between said input shaft and said first main shaft; a second multi-cone clutch torque transmitting elements operable for establishing drive connection between said input shaft and said second main shaft; - The double multi-cone clutch transmission preferably further comprises: an electrically powered actuators controlling gradual engagement or disengagement of torque transmitting elements of multi-cone clutches; an electrically powered actuators for controlling actuation of synchronizers and releasable coupling of dog clutches; The double multi-cone clutch transmission preferably further comprises: a multi-cone clutch torque transmitting elements for establishing a gradual drive connection between said input shaft and said main shafts; a multi-cone clutch pressure element operable by electrically powered coils to establish a gradual drive connection between said input shaft and said main shafts; a coil springs to establish required pressure onto said pressure element of said multi-cone clutch for torque transmitting connection between said input shaft and said main shafts. The double multi-cone clutch transmission preferably further comprises: a synchronizer hub having friction surfaces and adapted to axially move on shaft for establishing a contact with a friction surface of free rotating gear to synchronize the rotary speed of said shaft to that of said free rotating gear; a dog clutch sleeve adapted to axially move on said synchronizer hub for establishing a releasable drive connection between drive and driven gear; a locating spring loaded pins placed therein in said synchronizer hub for ensuring neutral position of said hub when synchronization of the rotary speed between said free rotating gear and said shaft is accomplished; a locating spring loaded pins placed therein in said dog clutch sleeve for ensuring said dog clutch position in engaged or neutral mode; a carrier plate appropriately formed to be fixed to box casing and to accept electric solenoid coils; a pair of solenoid coils for exerting a magnetic axial force on demand for moving . said synchronizer hub and dog clutch sleeve. ^{• v} According to a preferred form of the invention, there is. provided a system ^*of gears and direct electric gear shift devices in the first transmission embodiment encompassing single multi-cone clutch, said system comprising; ¹ one drive shaft driven by a power source, adapted to hold a fixed and free rotating gears of different diameters; * *. one driven shafts adapted to hold a fixed and free rotating gears of different diameters; a single multi-cone launch device having one torque transmitting member attached to the power source and the other torque transmitting member to the input drive shaft and number of intermediate torque transmitting members disposed between and having engagement with both the first mentioned torque transmitting members; a set of direct electric gear shift devices received by both drive and driven shaft; the said devices adapted to engage free rotating gears for transmission of power from the drive shaft to the output shaft; a set of bearings received by casing to support drive shafts; a set of housings to support gear selection devices and shafts.

According to a second preferred form in the second transmission embodiment encompassing double multi-cone clutch and direct electric gear shift devices, according to the invention said system comprising; one drive shaft driven by a power source adapted to hold torque input transmitting members of both double multi-cone clutches; first drive shaft adapted to hold a fixed gears of different diameters and adapted to receive other torque transmitting member of first double multi-cone clutch and. Second drive shaft adapted to hold a fixed gears of different diameters and adapted to receive other torque transmitting member of second double multi-cone clutch and; number of intermediate torque transmitting members disposed between and having engagement with both the first mentioned torque transmitting members; a set of direct electric gear shift devices received by both first and second driven shaft; the said devices adapted to engage free rotating gears for transmission of power from the drive shafts to the output shaft; a set of bearings received by casing to support drive shafts; a set of housings to support gear selection devices. Further objects and advantages of the invention will appear from the following detailed description iaken in conjunction with the accompanying drawings, which illustrate the manner of constructing and operating a transmission embodying the present invention. ^■<

DESCRIPTION OF THE DRAWINGS Figure 1 is a general view of six speed two-shaft arrangement for automated manual transmission using direct electric gear selectors and direct electric multi-cone clutch as launch device.

Figure 2 is a sectional view A-A of Figure 1 showing two-shaft and direct electric gear selector arrangement including wiring outlet. Figure 3 is a sectional view B-B of Figure 4 showing general arrangement of direct electric gear selector.

Figure 4 is an end view showing direct electric gear selector. Figure 5 is an enlarged view of Figure 3 showing dog clutch in engagement position with the gear. Figure 6 is a sectional view C-C of Figure 7 showing six-speed three-shaft automated manual transmission arrangement using direct electric gear selectors and direct electric double multi-cone clutch.

Figure 7 is an end view of six-speed three-shaft arrangement for automated manual transmission. Figure 8 is an enlarged view of double multi-cone clutch arrangement as per Figure 6.

DETAILED DESCRIPTION OF THE INVENTION As indicated above, the transmission system of the invention is based on a cluster of fixed and free rotating gears, of different diameters, appropriately arranged on drive and driven shafts. The fixed gears of drive shafts are permanently meshed with the free rotating gears of corresponding driven shafts. One direct electric gear selection device is positioned between two free rotating gears on the same shaft. This device has been arranged in manner to engage one gear in time to transmit the power to the output shaft. Each gear selection device consists of two electric solenoids housed in a frame firmly fixed to the housing. A sliding hub incorporating synchronizer occupies the space between the solenoid and the shaft. The hub is engaged to the shaft by splines and it slides axially in both directions. The outer perimeter of hub receives male part of dog clutch sleeve. The plunger is firmly connected to the outside perimeter of dog clutch sleeve and they slide together axially on splines formed in the outer perimeter of hub in both directions from its middle neutral point. To better understand the workings of a synchronizer and gear clutch as depicted in this invention the following is a short description of a solenoid and plunger theory as it can be found in any electrical engineering handbook related to the topic. A solenoid is a winding of insulated conductor and is wound helically; the direction of winding can be either right or left. A tractive solenoid is one designed to exert a force on the load through some distance and thus do work. Solenoid and plunger is a solenoid provided with a movable iron rod or bar called plunger. When the coil is energized, the iron rod becomes magnetized and the mutual action of the field in solenoid on the poles created on the plunger causes the plunger to move within the solenoid. The force becomes zero only when the magnetic centres of the plunger and solenoid coincide. If the load is attached to the plunger, work will be done until the force to be overcome is equal to the force that the solenoid exerts on the plunger. When the iron of the plunger is not saturated, the strength of magnetic field in the solenoid and the induced poles are both proportional to the exciting current, so that the pull varies as the current squared. When the plunger becomes highly saturated, the pull varies almost directly with the current. The maximum pull in Newtons [N] occurs when the end of plunger is at the centre of the solenoid and is equal to: F = 397,840*B^Λ2*A [N] where A is the cross section area of the plunger in [m^Λ2] and B is magnetic flux in [Weber/m^Λ2]. As depicted in this invention the iron is made as hollow bar of high magnetic property and it is firmly fixed to the outside of dog clutch sleeve thus both parts together form a plunger which is moved by force induced by solenoid. The solenoid design is of kind to be able to feed current flow from either end thus enabling it to change the direction of magnetic forces in either direction. An electronic switching device will be employed to do this function. As shown in drawings two solenoids are used to operate one plunger. One function of two solenoids is to keep plunger in the neutral position. This is achieved by opposing forces when both solenoids are energized with current flowing in opposite direction. One solenoid produces adequate axial force to move synchronizer along the shaft and engage dog clutch within predetermined time, however second solenoid can be energized to boost axial force if required. Each gear apparatus has inbuilt the position sensing device indicating whether dog clutch is engaged. These operating combinations are all possible due to the modern electronic control systems employed in automotive industry.

A wet lype multi-cone clutch is used as a launch device. The actuation system for multi-cone clutch is also based on solenoid and plunger concept. As showniiin the figures enclosed the inner pressure cone has been formed to act as a plunger with solenoid firmly attached to the clutch housing. A compression spring exerts pressure on inner cone and keeps friction cones in closed position for transmission of engine torque. It has to be noted that multi-cone clutch inherently uses several times less of axial force for transmission of the same torque when compared to an equivalent flat multi-disc clutch. For this reason multi-cone clutch can be loaded by a simple compression spring and opening and closing can be controlled by an electric solenoid as shown in accompanied figures. Friction cones are attached to inner cone by way of slots allowing axial movement and separator cones are attached to outer cone by way of slots allowing axial movement too. Under pressure exerted by the compression spring(s) inner cone compresses both friction and separator cones against outer cone thus providing one solid body for transmission of input torque. The combination of direct electric gear selectors and direct electric multi cone clutch used for launch device as described in this invention show that the targets to minimize the interruption times are achievable and driver's comfort could be comparable with the automatic transmission. Based on solenoid and plunger theory and formulas it can be shown that shift times can be as low as 20 ms (milliseconds). Opening of launch clutch is normally a fast action while closing of launch clutch can be also rapid but to achieve smooth launch and transition between gear shifts the closing of clutch is carried out by allowing friction elements to slip for certain period of time. The clutch slip is regulated by electronic system, which controls the magnitude of axial force.

The proposed direct electric gearshift system in combination with the multi-cone clutch as a launch is flexible to the extent that the gearshift times can be controlled to suit driver comfort and mode of drive by use of the electronic hardware and software control systems. It is also very important to notice that the power is used only during the shift time thus parasitic power loss has reached its minimum a great improvement when compared with the other actuation systems where the force is required to be maintained all the time while gear is engaged.

It can be said that the proposed transmission arrangement represents an appealing alternative transmission solution to the automotive industry. It meets targets so far not been accomplished by transmission or vehicle manufacturers. These include possible smallest transmission an-aspect very important especially when front wheel drive transmissions are considered. Due to shortened times for launch clutch and gear engagement by use of direct electric system for launch clutch and gear actuation a considerable improvement in fuel efficiency can be realized. From a manufacturing cost point of view this kind of proposed transmission would have an influential factor to be considered and that is the simplicity of proposed electric systems for gear selectors and launch clutch which by its design concept do not add significant cost penalty over deleted components from standard manual transmission. In preferred format, the drive shaft accommodates six drive gears each gear selected and matched with the gears on the output shaft. The number of drive gears in the system can exceed six, the absolute limit being governed by an overall gear ratio and box size.

Operation of the transmission is advantageously under the control of a programmable logic controller. Speed sensors are provided to monitor speed of the input and output shafts for selection of gears to be quick and precise to optimise output torque and power of the drive unit.

As mentioned above the automated manual transmission is based on the existing technology of modern manual transmissions. The invention uses basic components of the conventional manual transmissions incorporating few new features and a number of design modifications required to achieve the objectives of the automatic transmissions.

The design modifications or variations of the manual transmission components and other mechanical components employed by this invention do not require the development of new technologies.

The power-interrupt transmission using a single launch multi-cone clutch allows gears to be selected in random order where both devices launch clutch and dog clutches are automatically controlled. This type of automotive transmission is well understood in the industry.

Full power-shift transmission using double launch multi-cone clutch allows gears to be selected in sequential order only. The operation of double multi-cone clutch, three- shaft transmission is described in the following steps reflecting a typical automotive application: 1. An input shaft comprising three coaxial shafts: first shaft formed with double clutch torque transmitting members; second shaft coupled to first multi-cone clutch by torque transmitting members and third shaft coupled to second multi-cone clutch by torque transmitting members.

2. First drive shaft has fixed odd gear numbers, 1 , 3 and 5 as well as reverse gear, which are meshed with gears on first driven shaft. First gear is selected by disengaging first clutch. By its gradual engagement it functions as a launch.

3. Second drive shaft has fixed even gear numbers 2, 4 and 6, which are meshed with gears on second driven shaft. By disengaging said second clutch it is possible to engage second gear while the first gear is still in driving mode. To switch to second gear here is requirement for the first clutch to disengage and second clutch engage simultaneously. A slip of both clutches is present and a full power-shift from first to second gear is enabled

4. Further gear change is done in the same manner but in sequential order.

5. Output shaft meshed with two driven shafts. 6. Down-shift of gears is in reversed order to up-shift.

Having broadly described the transmission and operation of gear system, a detailed example will now be described with the reference to the accompanying drawings. The same item numbers are used for identical components of figures. Referring to Figure 1 , there is shown general view of two shaft six-speed box having direct electric gear shift arrangement and single multi-cone launch comprising: a drive shaft 1 which contains a cluster of gears 2, 3, 4, 5, 6, 7 and 8 each gear having its own diameter. All gears on shaft 1 are formed to mesh with gears 2A, 3A, 4A, 5A, 5 6A, 7A, and 8A of the output shaft 9. Gears 4 and 5 on shaft 1 and gears 2A, 3A, 6A, 7A and 8A on shaft 9 are free rotating. The ends of shaft 1 and shaft 9 are supported on bearings 10, 11 , 12 & 13 received by casing 14 and clutch housing 15.

Shaft 1 with gears 2, 3, 4, 5, 6, 7 and 8; shaft 9 with gears 2A, 3A, 4A, 5A, 6A, 7A and 8A of Figure 1 and four gear selection devices 16 as shown in Figure 1 and 2 10 compose a technical assembly which, when in operation present six-speed automated manual transmission. Details of gear selector are shown in Figures 3, 4 and 5.

Referring to Figures 3, 4 and 5, there is shown gear selection apparatus comprising: Two solenoid coils 17 so formed to be received by a rigid frame 18 which is attached to the wall of casing 19 as shown in Figure 2 by a screw 20 and two locating

-• 15 pins 21. The said solenoids are formed with an oversized hole, which allows fitment,

. free rotation and axial movement of clutch assembly unit 23 comprising plunger 23A

.■;^■• <;and dog clutch sleeve 23B a&shown in Figure 5. Power cables 22:are laid out within the frame 18 so they can be brought outside casing 19 for connection to power supply and

' fc control unit. Sensors 37 and 37A to detect engaged or neutral positions of dog clutch

20 are built in solenoids therein. The dog clutch sleeve 23B is received by splines 24 on the periphery of synchronizer hub 27. The synchronizer hub 27 is received by splines 25 of the shaft 1 or 9 and it slides along the shaft in space provided. Two spring-loaded pins

26 positioned at 180 degrees to each other are screwed into synchronizer hub to keep it in a position within notch 26A cut into the shafts 1 or 9 as per Figure 5. The end faces

25 of said synchronizer hub 27 are angled and lined with friction material 28 and 28A for fast synchronization of gear 29 or 30 with speed of shafts 1 or 9. The plunger and dog clutch assembly 23 move relative to hub 27 within limits of notches 32, 33 and 34, which are cut in the said hub. Two spring-loaded pins 31 positioned 180 degrees opposite to each other ensure that dog clutch does not slide out from notch 34 to maintain its

30 engagement with gear 29 and when in notch 33 does not slide out from its engagement with gear 30. Dog clutch sleeve 23B is formed to engage with mating parts 35 and 35A which are formed as a part of gears 29 and 30. Dog clutch sleeve 23B and plunger 23A are firmly fixed to each other and are moved along splines 24 relatively to hub 27 by a magnetic force generated by coils 17 and 17A to positions 33 or 34 for engagement with gears 29 or 30 as shown in Figure 5 for transmission of rotation from input shaft to output shaft.

Referring to Figures 6 and 7, there is shown gear selection apparatus applied to three shaft six-speed transmission comprising: Input shaft 38 adopted to carry outer cone of twin multi-cone clutch 40; two solenoids 45 and 45A so formed to be received by box housings 54 and 55 as shown on Figure 8; drive shaft 39 with integral gears 2, 4 and 6; drive shaft 41 with integral gears 1 , 3, 5 and reverse gear R; inner pressure cones 46 and 46A received by splines 47 and 47A formed in shafts 39 and 41 ; set of friction and separation cones 53 and 53A adopted for axial movement in slots made in outer and inner cones; a set of compression springs 48 and 48A; a system of needle bearings 49, 50, 51 and 52 mutually supporting shafts 38, 39 and 41 ; a gear selection apparatus 16 with typical arrangement as shown in Figure 6 and 8; a drive shaft 43 and an output shaft 44 as shown in Figure 7.

It has to be noted that details pertaining to shaft 43 and 44 have not been shown ' because of clarity of drawings and also because of their similarity and identical gear

'- ,.. selection devices as shown on shaft 42. • . . ""

As indicated shaft 41 carries the odd-numbered forward gears and reverse ge^'ar₃, and the shaft 39 carries the even gears. When a shift is required the next gear up or down can be. pre-engaged, after which one clutch is released while the -other is simultaneously engaged. This process can be extremely fast because of direct electric gear selectors as well as direct electric clutch actuation systems. The shift process is dependent on synchronisation of the two clutch movements. Interaction with the engine control unit to modulate torque output is essential for smooth change of gears and avoidance of vehicle pitching. The change is sequential meaning that gear jumping is not possible.

The operation of gear selection devices is identical to one described previously in Figure 3, Figure 4 and Figure 5 for a single multi-cone launch clutch and two-shaft box configuration.

This invention exemplifies the use of a direct electric gear selector as a device for engaging gears and direct electric launch operating device. However, it will be apparent to ones skilled in the art that other kinds of conventional direct electric devices could be adapted to and used without departing from the concept of the invention. It will be appreciated that many modifications can be made to the transmission general arrangement system as exemplified above without departing from the broad ambit and scope of the invention.

Claims

1. A single multi-cone clutch transmission for use in motor vehicle, comprising: a rotational input shaft supporting a set of fixed and free rotating gears which are meshed with corresponding gears on output shaft; 5 a rotational output shaft supporting a set of fixed and free rotating gears which are meshed with corresponding gears on input shaft; a multi-cone launch clutch operable for establishing a releasable drive connection between engine and said input shaft;

2. The single multi-cone clutch transmission of claim 1 further comprising:

10 an electrically powered actuator controlling gradual engagement or disengagement of multi-cone clutch; an electrically powered actuators for controlling actuation of synchronizers and releasable coupling of dog clutches;

3. The single multi-cone clutch transmission of claim 2 further comprising:

15 a synchronizer hub adapted to axially move on shaft for establishing a contact of its friction surfaces with a friction surfaces of free rotating gears to

Λ synchronize the rotary speed of said shaft to thafcof said free rotating gear; a dog clutch sleeve adapted to axially move on said synchronizer hub for establishing a releasable drive connection between drive and driven gear;

20 a locating spring loaded pins placed therein in said synchronizer hub for ensuring neutral position of said hub when synchronization of the rotary speed between said free rotating gear and said shaft is accomplished; a locating spring loaded pins placed in said dog clutch sleeve for ensuring said dog clutch sleeve selectable position therein in the said hub;

25 an electric solenoid coils carrier plate appropriately formed and fixed to box casing; a pair of solenoid coils for exerting a magnetic axial force on demand for moving said synchronizer hub and dog clutch sleeve.

4. A double multi-cone clutch transmission for use in motor vehicle, comprising; 30 a rotational input shaft incorporating torque transmitting element of double multi- cone clutch; a first main shaft rotationally supporting a set of fixed drive gears which are meshed with corresponding driven gears on output shaft; a second main shaft rotationally supporting a set of free fixed drive gears which are meshed with corresponding gears on output shaft; an output shaft rotationally supporting a set of free rotating gears which are meshed with corresponding gears on first and second main shaft; a first multi-cone clutch torque transmitting elements operable for establishing drive connection between said input shaft and said first main shaft; a second multi-cone clutch torque transmitting elements operable for establishing drive connection between said input shaft and said second main shaft;

5. The double multi-cone clutch transmission of claim 4 further comprising: an electrically powered actuators controlling gradual engagement or disengagement of torque transmitting elements of multi-cone clutches; an electrically powered actuators for controlling actuation of synchronizers and releasable coupling of dog clutches; '

6. The double multi-cone clutch transmission of claim 5 further comprising: a multi-cone clutch torque transmitting elements for establishing a gradual drive connection between said input shaft and said main shafts; -; a multi-cone clutch pressure element operable by electrically powered coils to " : establish a gradual drive connection between said input shaft and said main shafts; a coil springs to establish required pressure onto said pressure element of said multi-cone clutch for torque transmitting connection between said input shaft and said main shafts.

7. The double multi-cone clutch transmission of claim 5 further comprising; a synchronizer hub having friction surfaces and adapted to axially move on shaft for establishing a contact with a friction surface of free rotating gear to synchronize the rotary speed of said shaft to that of said free rotating gear; a dog clutch sleeve adapted to axially move on said synchronizer hub for establishing a releasable drive connection between drive and driven gear; a locating spring loaded pins placed therein in said synchronizer hub for ensuring neutral position of said hub when synchronization of the rotary speed between said free rotating gear and said shaft is accomplished; a locating spring loaded pins placed therein in said dog clutch sleeve for ensuring said dog clutch position in engaged or neutral mode; a carrier plate appropriately formed to be fixed to box casing and to accept electric solenoid coils; a pair of solenoid coils for exerting a magnetic axial force on demand for moving said synchronizer hub and dog clutch sleeve.

8. A direct electric gearshift system in combination with a multi-cone clutch as a launch device enabling disconnection of drive during gear change.

9. A direct electric gearshift system in combination with a multi-cone as launch device according to claim 8 in a transmission according to any one of claims 1-7.