POWER TRANSMISSION MECHANISM TECHNICAL FIELD

The present invention relates to a power transmission mechanism comprising an AC motor; a first drive group having a flywheel driven by said AC motor; a second drive group having at least one drive means whose revolution is changeable; and a planet gearbox where the outlets of said first and second drive groups are joined and where a single outlet is obtained.

PRIOR ART

There are cases where the power, obtained from the outlet in the production region, should be controlled in a dynamic manner.

Accordingly, the presses, known in the related art, are functioning by means of the kinetic power of the flywheel accelerated by an electric motor. Accordingly, the flywheel rotates continuously by means of the rotation movement obtained from the motor, however, the flywheel shaft does not rotate. When the piece is desired to be pressed, the flywheel shaft begins rotating by means of a clutch mechanism like pedal. The rotation movement in the flywheel shaft is transferred to the camshaft, which functions as a crank, after the revolution number is decreased and after the torque is increased. The function of the eccentric shaft is to transform circular movement to linear movement. Thus, linear movement (called press movement distance or stroke in the related technical field) is provided for the axial eccentricity of the crank shaft to the movable head connected to the connecting rod in connection to the crank shaft of the press.

In the traditional presses described above, the movement of the ram can be controlled only by the grabbing-releasing process and by the control of the flywheel speed. Therefore, for instance, during the pressing process, the speed of the ram can be controlled in a very delimited manner or the particular cases, where the ram is stopped at certain points for a certain duration, cannot be performed. This provides delimited shaping processes in traditional presses.

The control of the flywheel speed for controlling the movement of the ram in the abovementioned traditional presses becomes possible as the revolution numbers of the electrical motors, which are in connection to the flywheel, are changed. In order for flywheels having substantial kinetic energy, electrical motors with high level of power are used.

In order to prevent this disadvantage, servo presses are described in the related technical field. In servo presses, the movement and the speed of the ram is controlled by a powerful servo motor. However, servo presses are expensive machines because of the servo motors thereof and the capability of servo presses are delimited by the servo motor thereof.

In addition to the abovementioned details, power transmission mechanisms are provided which are functioning according to the two input-one output principle. For instance, in the patent application US 5425682, a power transmission shaft is disclosed which transmits the rotational power of the flywheel and which is divided into a first shaft part adjacent to the flywheel and into a second shaft part adjacent to a power decreasing gear. Accordingly, between said shaft parts, a planet gear box is embodied driven by a servo motor. Said power decreasing gear is connected to the outlet of said planet gear box in order to transmit the power to the load. The servo motor is controlling the rotation of the outlet part of the planet gear box. Thus, the rotation of the power decreasing gear can be changed and as a result of this, parameters, like the movement speed of the ram, can be controlled in the desired manner. A disadvantage of the invention described in US 5425682 is that the dimensions thereof are big and power consumption is at a high level.

As a result, because of the abovementioned problems, an improvement is required in the related technical field. BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a novel power transmission mechanism, in order to eliminate the abovementioned problems and to bring new advantages to the related technical field. The main object of the present invention is to provide a power transmission mechanism comprising a continuously changing transmission box and which is functioning according to the two input one output principle.

Another object of the present invention is to provide a compact power transmission mechanism which provides changing of the output revolution in a dynamic manner. In order to realize all of the abovementioned objects and the objects which are to be deducted from the detailed description below, the present invention relates to a power transmission mechanism comprising an AC motor; a first drive group having a flywheel driven by said AC motor; a second drive group having at least one drive means whose revolution is changeable; and a planet gearbox where the outlets of said first and second drive groups are joined and where a single outlet is obtained. Said power transmission mechanism is characterized in that the first drive group moreover comprises at least one continuously changing transmission box provided between the inlet of the planet gear box and the outlet of said flywheel; and the second drive group comprises at least one AC motor; at least one flywheel driven by said AC motor; at least one continuously changing transmission box provided between the outlet of said flywheel and the inlet of the planet gear box.

In a preferred embodiment of the subject matter invention, at least one connection member is provided in order to provide movement transfer between continuously changing transmission boxes and the planet gear box.

In another preferred embodiment of the subject matter invention, said connection members comprise at least one transmission part for transferring the movement applied by the first flywheel; and at least one first work shaft provided at the continuation of said transmission part.

In another preferred embodiment of the subject matter invention, the connection members comprise at least one transmission part for transferring the movement applied by the second flywheel; and at least one second work shaft provided at the continuation of the transmission part.

In another preferred embodiment of the subject matter invention, said first work shaft drives the orbit gear provided inside the planet gear box; and said second work shaft drives the sun gear provided inside the planet gear box.

In another preferred embodiment of the subject matter invention, the continuously changing transmission box is a continuously changing transmission box which is functioning together with the gear system. In another preferred embodiment of the subject matter invention, the present invention is a metal processing machine comprising the power transmission mechanism and it is particularly a press. In order for the embodiment and the advantages of the subject matter invention to be understood in the best manner with the additional elements, it has to be evaluated with the detailed description and with the figures explained below. BRIEF DESCRIPTION OF THE FIGURES

In Figure 1 , the schematic view of a power transmission mechanism is given. In Figure 2, the schematic view of a planet gear box is given.

REFERENCE NUMBERS

10 Power Transmission Mechanism

20 Inlet Part

21 AC Motor

22 Flywheel

22a First Flywheel

22b Second Flywheel

23 Continuously Changing Transmission Box

24 Connection Members

241 Work Shaft

241 a First Work Shaft

241 b Second Work Shaft

242 Transmission Part

30 Outlet Part

31 Planet Gear Box

31 1 Orbit Gear

312 Sun Gear

313 Planet Gear

314 Planet Carrier

32 Outlet Shaft

THE DETAILED DESCRIPTION OF THE INVENTION In this detailed description, the subject matter power transmission mechanism is explained with references to examples without forming any restrictive effect in order to make the subject more understandable. Accordingly, in the detailed description and in the figures below, the present invention is assumed to be used in providing movement to the ram of a press. However, in alternative embodiments, the present invention can also be used in any other field where power transmission according to the two input one output principle will be preferred.

With reference to Figure 1 , the schematic view of a power transmission mechanism (10) used in presses (not illustrated in the figure) is given. Said power transmission mechanism (10) comprises two main parts. These parts are the input part (20) and the output part (30). Said input part (20) provides the required power for the activation of the ram (not illustrated in the figure). In more details, two flywheels (22a, 22b) are in connection in the inlet part (20). Said flywheels (22a, 22b) are positioned at a certain distance from each other and in a symmetrical manner. There are AC motors (21 ) in connection to the flywheels (22a, 22b). Continuously changing transmission boxes (23) are connected to the flywheels (22a, 22b). Said continuously changing transmission boxes (23) are defined as CVT. The CVTs (23) are positioned at the edge of the flywheels (22a, 22b), which are opposite to the edge whereto said AC motors (21 ) are connected. There are connection members (24) in connection to the CVTs (23). Said connection members (24) have a Z-like view. The connection members (24) comprise two parts. Said two parts are the transmission part (242) and the work shaft (241 a, 241 b). Said transmission part (242) is positioned so as to be adjacent to the CVT (23) and it is in connection so as to receive the movement in the CVT (23). The transmission parts (242) are approaching so that there is at least substantial space in between at a vicinity of the region existing between the CVTs (23). Said work shafts (241 a, 241 b) are connected so as to be adjacent to the point the transmission parts (242) are approaching thereto. The work shafts (241 a, 241 b) receive the movement transferred by the transmission parts (242). The first and the second work shafts (241 a, 241 b) are positioned in a parallel manner to each other. Around the work shafts (241 a, 241 b), there is a planet gear box (31 ) in connection. Said planet gear box (31 ) is embodied and positioned so as to accommodate the work shafts (241 a, 241 b). With reference to Figure 2, there is an orbit gear (31 1 ) which is in connection to the planet gear box (31 ) such that there is movement freedom. The planet gear box (31 ) comprises said orbit gear (31 1 ) and in addition, a sun gear (312) positioned at the center and four planet gears (313) whose gears are connected to the threads of the orbit gear (31 1 ) and of said sun gear (312) connected to the planet carrier (314) by means of one each fixation shaft (not illustrated in the figure) such that there is rotation freedom. The shaft of the sun gear (312) is bedded inside said planet carrier (314). The sun gear and said planet gears (312, 313) are provided on a planet carrier (314) whereon an output shaft (32), defining the system output, is connected so as to be concentric. Said planet carrier (314) is freely rotatable around the own axis thereof inside the arrangement. Thus, rotation freedom between the planet carrier (314), the flywheel (22a, 22b) and the sun gear (312) is provided. The first work shaft (241 a) receiving the movement applied by the first flywheel (22a) is in connection to the orbit gear (31 1 ) with the help of a gear mechanism (not illustrated in the figure). The second work shaft (241 b), receiving the movement applied by the second flywheel (22b), is in connection to the sun gear (312) with the help of a gear mechanism. The work shafts (241 a, 241 b) are positioned so as to drive the gears the work shafts (241 a, 241 b) are connected thereto.

The power transmission mechanism (10) generally performs the process of reducing the produced power from two inputs to one output in order to activate the presses. The AC motors (21 ) produce the required rotation movement for activating the flywheels (22a, 22b) and they rotate the flywheels (22a, 22b) in a continuous manner. The flywheels (22a, 22b) accumulate kinetic energy thereon by means of the rotation movement and they provide the driving of the press. During the whole operation, the flywheels (22a, 22b) rotate in a fixed speed. The first flywheel (22a) and the second flywheel (22b) rotate in opposite directions. The CVTs (23) proportionately decrease or increase the rotation movement received from the flywheels (22a, 22b). The proportion changing duration of the CVTs (23) is very short and it does not affect the performance of the press. The rotation movement obtained from the output of the CVTs (23) is transferred to the connection members (24). The work shaft (241 a, 241 b) transfers the movement, applied by the CVT (23) by means of the transmission part (242), to the planet gear box (31 ) and thus to the gear. The first work shaft (241 a) transfers the movement to the orbit gear (31 1 ) and provides the rotation of the orbit gear (31 1 ). The second work shaft (241 b) transfers the movement to the sun gear (312) and provides the rotation of the sun gear (312). The planet gears (313) drive the planet carrier (314) by means of the drive obtained from the sun gear (312) and from the orbit gear (31 1 ) and they provide the rotation of the planet carrier (314). The planet carrier (314) transfers the drive formed by the planet gear box (31 ) to said output shaft (32). The output shaft (32) provides the driving of the press and provides the activation of the ram.

The general operation of the system is as follows. The AC motors (21 ) begin rotating the flywheels (22a, 22b). As a result of the rotation of the flywheels (22a, 22b), the CVTs (23) are activated and the circular movement, whose rotation speed is changed as desired, is transferred to the transmission part (242) and thus to the work shaft (241 a, 241 b). Meanwhile, the proportions of CVT (23) can be changed and this change is performed in a very short time. The planet gear box (31 ), receiving the movement from the work shafts (241 a, 241 b), reduces the two inputs to a single output, and it drives the ram by means of the output shaft (32). In this system, there remains no need to use servo motors (not illustrated in the figure) in connection to the flywheels (22a, 22b) by the usage of the CVTs (23), and the proportions of power required for the costs and operation are reduced substantially.

The protection scope of the present invention is set forth in the annexed Claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention.