Object of the invention is an electromechanical power unit intended for motor vehicles.

Nowadays, motor vehicles, in addition to traditional internal combustion engines, are additionally driven by electric motors as so-called hybrid vehicles or by electric motors only. The driving torque from these motors is transferred by suitable systems to the wheels of the vehicle.

From U.S. Patent Description No. 5,120,282 there are known vehicle transmission systems comprising, at least one drive shaft, at least one motor and at least one planetary gear composed of a satellite, a sun gear and a ring gear. The motor is coupled to the sun gear via a gear transmission, and the relative speed between the sun gear and the drive shaft is controlled by supplying energy to and receiving energy from the motor. The sun gear is pivotally mounted on the drive shaft, and the drive shaft is rigidly connected to the planet gear yoke. Basic driving force /torque/ is transferred from the motor to the ring gear of the planetary gear via the gearbox. As a result of such a system, when the sun gear is retarded by the motor, via the gear transmission, the satellites’ yokes rotate around the center of the gear and they drive the drive shaft regardless of the retardation of the sun gear.

Also from the U.S. Patent Description No. 5,947,855 there is known a vehicle drive system comprising a generator powered by an internal combustion engine and a drive axle having a pair of wheels, each wheel being driven by a related electric motor powered, in turn, by the generator. The internal combustion engine also drives the drive shaft, which is connected to the drive axle. The drive system also contains a pair of summing gears, each of which has an output shaft connected to the corresponding wheel, and each summing gear has a first input connected to the drive shaft and a second input connected to the corresponding electric motor.

Also from the description of the European patent EP3805029A1 , a power system for a hybrid vehicle is known. The power system of the hybrid vehicle, according to this invention, adopts a first planetary gear mechanism with two sun gears, where the first sun gear rotates together with the input shaft, and the second sun gear and the input shaft are independent of each other, and the second sun gear achieves different motions due to a second brake and/or a second clutch and it cooperates with the first brake to provide different gear ratios when the internal combustion engine and the electric motors operate while driving.

Existing drive systems for hybrid or electric motor vehicles are relatively large and heavy because of the need for multi-stage planetary gears in most cases.

Goal of the invention was to design an electromechanical power unit for motor vehicles that makes it possible to adjust the gear ratio and replace the functions performed in a classic motor vehicle by a differential gear, using a minimum number of parts and multiple identical parts for the left and right sections of the assembly. In addition, the goal was to minimize the weight and dimensions of the power unit. This goal has been achieved due to the design of the power unit according to the invention.

The essence of the invention is that the electromechanical power unit for motor vehicles is equipped with at least one main motor, at least two electric auxiliary motors, an assembly comprising at least two cycloidal gears and a single or multi-stage mechanical transmission of the main motor driving the main wheel assembly of the cycloidal gear. Electric auxiliary motors drive the power input shafts of the cycloidal gears, and the toothed rim of the main wheel is coupled via a single or multi-stage mechanical transmission to the main motor or motors, while each power input shaft of the cycloidal gear is coupled by means of a single or multi-stage mechanical transmission to the electric auxiliary motor or motors. The power input shafts of cycloidal gears have one or more cylindrical parts with axes eccentrically offset from the main axis of the power input shaft, and on these cylindrical parts of the power input shaft through the needle bearings there are mounted cycloidal discs. The outer contour of the cycloidal discs is a curve, such that the heads of the teeth are described by curves with an epicycloidal outline, and the feet of the teeth are described by sections of arcs of a circle, or any other arbitrary curve. The main wheel assembly, which includes two housing discs, two main wheel rings, toothed rim of the main wheel, rollers with bushings and connecting bolts. In addition, the main wheel assembly is equipped on its outer circumference with pivotally mounted bushings on the rollers, one bushing on each roller for one cycloidal disc, with the number of rollers of the main wheel assembly being greater than the outer contour teeth number of the cycloidal disc by one or two or three rollers.

The object of the invention is shown in the example in fig. 1 , fig. 2, fig. 3, fig. 4 and fig. 5, where the fig. 1 shows a top view of the power unit as a cross-section, fig. 2 shows the power input shaft with eccentrically offset cylindrical parts, fig. 3 shows a cycloidal disc with an epicycloid outer contour, fig. 4 shows structural details of the cycloidal gear, while fig. 5 shows the components of the cycloidal gear as an isometric view. The electromechanical power unit for motor vehicles shown in fig. 1 cons ists of a main motor /1 /, electric auxiliary motors 121, a cycloidal gear set /3/, a multi-stage mechanical transmission /4/ of the main motor /1/, a multi-stage mechanical transmission /5/ of the auxiliary motors 121, drive half-shafts /6/ and vehicle wheels 171. Shown in fig. 2, axes of the cylindrical parts /8a and 8b/, which pose integral parts of the power input shaft /9/, are offset eccentrically with respect to the main axis of the power input shaft /9/. On the eccentric parts of the power input shaft /9/ there are fixed the cycloidal discs /10/ and /11/ shown in fig. 3, the outer contour /12/ of which is formed by teeth of epicycloidal outline, and below the teeth there are holes 1221 in the number of eight or other. The fig. 4 shows the structural details of the cycloidal gear 131 consisting of a main wheel assembly, two pairs of cycloidal discs /10/ and /11/, and two power input shafts /9/ and two power output shafts /14/, first needle bearings /15/./16/, and second needle bearings /20/ and /21/. The fig. 5 shows the components of the cycloid gear /3/ in such a way that the left side of the gear is assembled, and the right side for easier illustration of the structure of the assembly shows the individual parts shifted as the isometric view, similar to the installation diagrams.

The electromechanical power unit for motor vehicles is composed of the main motor /1 /, electric auxiliary motors 121 and a cycloidal gear set 131. The cycloidal gear 131 consists of a hollow power input shaft /9/, where the first spur gear /17/ is fixed on the outer side, meshed with the second spur gear /18/, fixed rigidly on the shaft of the auxiliary motor 121. Then, towards the center of the mechanism, an inner bearing ring /19/ is seated on the power input shaft /9/ and the outer ring of the bearing /19/ is seated inside the bore of the gear housing disc 1231 of the cycloidal discs /10/ and /11/. Subsequently, on the power input shaft /9/ there are two cylindrical parts /8a/ and /8b/ which are an integral part of it, the axes of which are eccentrically offset from the main axis of the power input shaft /9/, with the axes of the two eccentrics offset from each other by an angle of 180 degrees. Through a hole hollowed in the power input shaft /9/ there is designed the pivot of the power output shaft /14/, seated coaxially with the power input shaft /9/ through two needle bearings /20/ and /21/. On the cylindrical parts /8a and 8b/ of the power input shaft /9/ via the needle bearings /15/ and /16/ there are seated cycloidal discs /10/ and /11/, the outer contours /12/ of which are formed by teeth with an epicycloid outline. In addition, the cycloidal discs /10/ and /11/ have holes 1221 of circular cross-section in the middle part, inside of which the pivots of the power output shaft /14/ are placed, on which the bushings 1271 (one on each pivot) are pivotally seated. On the inner side of the main wheel assembly, near its outer contour, a main wheel ring /13/ is placed. The components of the cycloidal gear 131 in form of the power input shaft /9/, the cycloidal discs /10Z and /11/, the first needle bearings /15 and 16/, the second needle bearings /20 and 21/, the bushings Z26Z, the shaft of the electric auxiliary motor 121, bearing /19/, housing disc /23/, first gear /17/, second gear /18/, main wheel ring Z13/, power output shaft /14/ have their mirrored images. The axis, with respect to which the mirroring takes place, is formed by the dividing plane of the gear housing. Between the rings of the main wheel /13/ there is a toothed rim /24/ cooperating with the minor gear /28/ of the intermediate shaft /29Z and rollers /25/, in the number of teeth of the cycloid disc /10/ plus one or two or three, on which bushings /26/ are applied in the number of one bushing on each roller /25/ for one cycloidal disc Z10/ and /11/. The left and right discs of the gear housing Z23Z are bolted together by bolts /30/ with the toothed rim Z24Z, through the rings of the main wheel Z13Z, constituting the main wheel assembly after the installation. On the intermediate shaft Z29/, on the side opposite to the minor gear /28/, there is a major gear /31/ cooperating with the gear /32Z of the main motor /1/, seated on the shaft of the main motor /1/.

The electromechanical power unit for motor vehicles operates in the such a way that the main motor /1 / transmits torque to the toothed rim /24/ of the cycloid gear 131 main wheel via a mechanical transmission of the main motor 141 comprising a minor gear /28Z, an intermediate shaft Z29/, a major gear /31 Z and a gear 1321 of the main motor /1 /, while electric auxiliary motors 121 through additional mechanical transmission 151 comprising the first and the second spur gears Z17/ and /18/ drive the power input shafts /9/. During operation of the electromechanical power unit it is possible to transmit different driving torque and speed to the left and right wheels of the vehicle 171. Varying the rotational speed and driving torque to the wheels is possible by independent control of the rotational speed and driving torque of the electric auxiliary motors 121.

The electromechanical power unit for motor vehicles, object of the invention, unlike previous designs, is characterized by smaller dimensions and lighter weight of the entire unit compared to designs based on planetary gears. This has been achieved due to a special design of the cycloidal gearbox according to the invention, which makes it possible to obtain, from a single stage, a practical ratio of more than 100:1 and theoretically even 300:1. This makes it possible to use it on a large scale in smaller vehicles, since thanks to its compact design it does not require much space for installation. This is particularly important when converting existing combustion engine car designs to hybrid or electric vehicles. In addition, the cycloid gearbox is characterized by quiet operation and low vibration level, and it has the ability to (withstand) overload several times more than planetary gearboxes, without risk of damage. The aforementioned characteristics contribute to a longer life of the mechanism and guarantee its trouble-free operation, even during operation in harsh conditions and with high variability of power output load.