RU2643903C1 - Self-propelled vehicle electromechanical transmission - Google Patents

Abstract

FIELD: agriculture; machine building.

SUBSTANCE: invention relates to industrial and agricultural tractors. Self-propelled machine electromechanical transmission comprises traction generator, connected to an internal combustion engine, a traction motor, side or wheel gears linked with a traction motor, as well as a traction motor and/or traction generator control system. One of the electric motor or generator is a reactive inductor, comprising a stator with poles and phase windings made in the form of lumped coils placed at the poles of the stator, and a rotor with a gear magnetic core fixed to its shaft. Brake is attached to the rotor shaft of the traction motor and/or the rotor shaft is hollow with the possibility of accommodating therein an elastic or compensating mechanical clutch, or a hydraulic clutch that is adapted to connect said shaft to a transfer device, or with an on-board reducer, or with a wheel gear, or with a matching device, or with an engine.

EFFECT: longer service life of transmission.

8 cl, 2 dwg

Description

The invention relates to industrial and agricultural tractors, loaders, graders, all-terrain vehicles and other tracked and wheeled self-propelled vehicles with an electromechanical transmission, designed to perform earthmoving, construction, road, transport, agricultural and other works.

Known electromechanical transmission of a caterpillar tractor containing an internal combustion engine (heat engine) associated with a traction generator, two traction motors kinematically connected to tracks of opposite sides, and an electrical equipment control system. The traction generator and traction motors are made synchronous, alternating current. The electrical control system includes a converter and a high-level microprocessor controller. Traction motors are placed in parallel in one housing [1].

The disadvantage of this device is its lack of reliability due to the use of synchronous electric machines, which are implemented with permanent magnets on the rotor. Low reliability is predetermined by the possibility of rotor destruction due to the action of centrifugal forces on the magnets, the inability of the transmission to operate when one of the phase windings fails, and the increased complexity of the windings, sections of which, as a rule, cover several teeth of the magnetic circuit.

Also known is a self-propelled machine with an electromechanical transmission, which has higher reliability and is closest to the proposed one. It contains an internal combustion engine (ICE), electrical machines, electronic controllers (commutators, inverters), power buses, an electric energy storage device and a control unit. One electric machine is kinematically connected to the internal combustion engine, and other electric machines (traction motors) are kinematically connected to the traction devices. The control unit is connected to electronic controllers (switches, inverters), and the electrical energy storage device is connected to power buses. As electric machines, reactive induction machines with self-excitation and gear-type passive ferromagnetic rotors are used. During the operation of electric machines, electronic switches (controllers) connect their phase windings (armature windings) to the power buses, which are made in the form of lumped coils placed at the poles of the stator [2].

The disadvantages of the known analog device are due to the characteristic feature of reactive induction machines, namely, the unevenness of their torque. During the rotation of the rotor, the moment periodically changes depending on its position. In this case, the resulting instantaneous moment consists of two components: constant (useful) and pulsating moment.

Ripples of the moment lead to a reduction in the service life of the transmission due to an increase in dynamic loads and the occurrence of torsional vibrations (including resonance) in the final drive and the device transmitting torque to it (in the transmission device). The presence of torque ripples leads to the need to implement special measures to reduce them, which simultaneously leads to a decrease in the output power of the transmission and traction power of the self-propelled machine.

The disadvantages of this device also include an increased technogenic impact on the soil (ground) of a wheeled or caterpillar propeller of a self-propelled vehicle, as well as its insufficiently smooth movement (the presence of longitudinal vibrations). This is due to the fact that changes in torque on the output axis of the onboard or wheel gear lead to a change in the driving force applied to the ground (soil, road surface or other traffic path). Moreover, the repeated cyclic loads applied to the soil (soil) cause the accumulation of deformations in it, since after the first application of the load, the deformation continues to increase with subsequent actions of the load.

The objective of the invention is the creation of an electromechanical transmission with an increased resource and at the same time providing increased power, smooth running of a self-propelled machine and its reduced man-made effect on the soil (earth, soil).

The problem is solved due to the fact that in an electromechanical transmission of a self-propelled machine containing a traction generator, which is directly or through a matching device connected to an internal combustion engine (ICE) and converts its mechanical energy into electrical energy, at least one traction motor that converts electrical energy into mechanical, final drives (for a self-propelled tracked vehicle) or wheel reducers (for a self-propelled wheeled vehicle) adapted to drive tracks and whether the driving wheels of the self-propelled machine and connected with at least one traction motor directly or at least through one transmission device, as well as the control system of at least one traction motor and / or traction generator, at least one of which is made of a reactive inductor, containing a stator with poles and phase windings made in the form of lumped coils placed on the poles of the stator, and a rotor with a toothed magnetic circuit mounted on its shaft, are provided with The following differences: the number of phases and the number of stator teeth are selected in such a way that the result of their product is equal to or more than 36, the rotor shaft is hollow with the possibility of placing inside it a mechanical coupling, or a hydraulic coupling, or a torsion bar, which / which is adapted / adapted to connect this shaft with a transmission device, or with an on-board gear, or with a wheel gear, or with a matching device, or with an internal combustion engine.

In addition, in private embodiments of the invention, in order to further improve the characteristics of an electromechanical transmission:

- traction motors and traction generator are made three-phase with 18 teeth of the stator and 12 teeth of the rotor;

- the mechanical coupling is made non-disengaged movable, preferably elastic or compensating;

- matching device is made in the form of a mechanical coupling of the engine and / or multiplier;

- the transmission device that connects the traction motor with final or wheel gears, contains the main gear, the outputs of which are connected to final drives using on-board friction clutches;

- the number of traction electric motors is set equal to the number of tracks or drive wheels of the self-propelled machine to provide an independent drive for each track or each drive wheel;

- the transmission device is made in the form of a matching gear, an input mechanical coupling of an onboard or wheel gear, a cardan gear, or a combination thereof;

- a disk electromagnetic parking brake of a self-propelled machine is mounted on the shaft of at least one traction motor.

To explain the effect of the distinctive features of the independent claim of the present invention on the achievement of the indicated technical result, it should be noted that various methods of reducing torque ripples of reactive induction machines are known from the prior art. In particular, special algorithms for controlling current in phase windings are used, the configuration of the teeth of the rotor and stator is optimized, etc. However, in the case of the effective implementation of these measures, there is a significant decrease in the output power and torque of electric machines of this type, which is unacceptable when creating electromechanical transmissions of self-propelled machines.

In the proposed invention, in contrast to the known technical solutions, the pulsation of the torque is suppressed not on the rotor shaft, but on the output link of the electric machine - on the driven part of the coupling or torsion bar. To this end, the specified clutch or torsion bar is placed inside the electric machine, namely inside its hollow shaft.

To provide such a possibility, in the design of the reactive induction machine, in accordance with the distinguishing features of the invention, a hollow rotor shaft with an increased inner diameter sufficient to accommodate a clutch or torsion bar is provided. This is ensured by choosing the number of phases and the number of stator teeth in such a way that the result of their product is equal to or more than 36.

Further, a mechanical coupling, a hydraulic coupling or a torsion of a traction electric motor or traction generator is connected, respectively, with a transmission device, an onboard / wheel gear, with a matching device or with an internal combustion engine. Accordingly, the pulsations of the torque (uneven rotation) do not go beyond the limits of the traction motors and the traction generator and do not lead to the appearance of torsional, including resonant, oscillations in the transmission. Due to this, an increase in the service life of the transmission is provided. At the same time, pulsations of the forces of interaction of the driving wheels or tracks of the self-propelled machine with the soil (ground, soil) are eliminated, which eliminates the longitudinal vibrations of the self-propelled machine, i.e. increase the smoothness of its course.

From the mechanics of soils (Kharhuta N.Ya. Rheological properties of soils. - M .: Avtotransizdat, 1961) it is known that repeated cyclic loads applied to the soil (soil) cause the accumulation of deformation in it. Having reached the value corresponding to the first application of the load, the deformation does not stop, but continues to increase with subsequent actions of the load.

Therefore, the implementation of the proposed distinctive features of the invention allows to reduce the negative impact of wheels or tracks on the soil (earth, soil) by reducing its compaction.

Reduced man-made impact on the soil (earth, soil) is also achieved by reducing the slipping of the drive wheels or tracks. This is due to the fact that at the border of the transition of the wheels or tracks to the slip mode, the rate of increase of the torque supplied to the wheels or to the drive sprockets of the tracks has a significant effect on their slipping.

In addition, the elastic element of the coupling or torsion provides the accumulation of vibrational energy caused by the uneven interaction forces of the stator and rotor. The resulting energy peaks are not eliminated, but accumulate in the specified elastic element, which leads to an increase in the average torque of the induction jet machine. Moreover, the presence of elastic elements of the coupling or torsion eliminates the need to use those methods to reduce the ripple of the torque of induction jet engines, which lead to a decrease in the average value of their output torque (power output). Accordingly, the implementation of the proposed distinctive features of the invention leads to an increase in the output power of the transmission.

It follows from the foregoing that the distinguishing features of the independent claim are in direct causal connection with the achieved technical result. The invention allows to create an electromechanical transmission with an increased service life and allowing to obtain increased power, ride and reduced man-made impact of a self-propelled machine on the soil (earth, soil).

To clarify the technical nature, principle of operation and feasibility of the proposed device in FIG. 1 as an example, a simplified diagram of an electromechanical transmission of a tracked self-propelled vehicle is shown. In FIG. 2 is an example of the active part of the traction generator and traction motors (electric machine) with a hollow shaft.

The proposed electromechanical transmission is used on a self-propelled machine, in which the role of the primary energy source is played by a drive motor 1, made, as a rule, in the form of an internal combustion engine (ICE).

In the given example, a sequential kinematic diagram of the motor-transmission installation of the machine is used, which excludes the mechanical connection of the internal combustion engine with the caterpillar mover.

ICE directly or through a matching device - a mechanical elastic or compensating engine coupling, a multiplier, etc., is connected to a traction generator 2, which is a source of electrical energy for two traction motors 3 and 4 connected to final drives 5, 6.

Implementation of transmission with one traction electric motor is also possible. In this case, the transmission device that connects the traction motor to the final drive or wheel gears contains the main gear with differential control, or with the final drive clutches and service brakes, which make it possible to turn the self-propelled machine.

Driving wheels (sprockets) 7, 8 of the caterpillar mover are fixed on the final drives.

The control system for an electromechanical transmission, which can also be called a control, protection and control system, an electrical equipment system, etc., in the general case, includes high-voltage and low-voltage parts of this system and contains one or more controllers, in particular, the main (leading) controller 9, a controller (power converter) 10 of the traction generator 2, two controllers (power converters) 11, 12 of the traction electric motors 3, 4, controls for the movement of the machine (transmission) 14, the operator panel (tra whoever, driver) 15, sensors for the parameters of the transmission and the machine as a whole 16 and devices for low-voltage equipment (power supply, lighting, audible alarm, etc.) and other devices not conditionally shown in the drawing.

Controllers 9-12 can also be called control units, control devices, input and load blocks, information control units or devices, etc. Traction motor controllers 11, 12 may also be referred to as power converters, inverters, etc.

The controller 10 of the traction generator 2, depending on the design of the generator (for example, in the case of a synchronous generator with permanent magnets on the rotor), can also be called a power controlled or uncontrolled rectifier that converts the alternating output voltage of the traction generator 2 into a constant voltage of the transmission busbars 17 , for example, 550 V.

For a self-propelled machine, it is preferable to have a common power bus 17, which allows a direct energy exchange between the left and right sides of the machine when maneuvering it with a corresponding decrease in energy absorption by a braking resistor and an increase in transmission efficiency.

An energy storage device made on the basis of batteries and / or capacitors, as well as a braking resistor and a power switch connected in series to the power bus if the voltage across them exceeds the maximum allowable value, can be connected to DC busbars 17.

The controllers 11 and 12 convert the direct voltage of the power buses 17 into alternating voltage or unipolar pulses that are fed to the phase windings of the traction motors 3, 4. They are made in the form of power converters on IGBT transistors and contain galvanically isolated drivers of these transistors, microcontrollers or digital signal processor, as well as interface devices adapted to exchange information with these controllers.

Depending on the functions performed and the requirements for the layout of the self-propelled machine, it is possible to combine the 9-12 controllers into a single unit (controller, module), or their separate execution. It is also possible to constructively combine the generator controller (power rectifier) 10 with the traction generator 2, and the controllers (power converters) 11, 12 with the traction motors 3, 4.

The information signal transmission lines between the controllers are made using the standard of the industrial CAN network (Controller Area Network - a network of controllers), focused on combining various devices into a single network using serial, broadcast and packet transmission modes. It is also possible to use interfaces LIN (Local Interconnection Network), RS-485 (EIA / TIA standard), etc., as well as wireless interfaces such as ZigBee (IEEE 802.15.4 standard), Wi-Fi (IEEE 802.11 standard), Bluetooth (IEEE 802.15.1 standard), etc.

The main controller (master controller, top-level controller) 9 coordinates the operation of all components (components) of the electromechanical transmission, including implements the control functions of the internal combustion engine 1 directly or through an additional engine controller built into it.

As shown in FIG. 2, the traction electric motors are made by a reactive induction motor and comprise an external casing (jacket, jacket) 18, in which the stator 19 with poles and phase windings, made in the form of lumped coils 20 placed on the poles of the stator’s lined magnetic circuit, and a rotor with a gear magnetic circuit 21 are placed also made of sheets of electrical steel and mounted on its shaft 22.

Such electric motors without a field winding are called in the Russian-language literature as induction jet reactive motors (WFD, VID, VIRD), and in the English-language literature as electric motors with variable magnetic resistance: “Switched Reluctance Motor (SRM)”.

To carry out liquid cooling of the traction motor in the gap 23 between its coils or in the recesses 24 of the magnetic circuit of the stator 17, tubes with a cooling liquid are connected, connected to an external circulation pump and a heat exchanger.

Traction generator 2 may have a design similar to or different from traction motors 3, 4.

In the traction electric motor (generator), the numbers of its phases and stator teeth are set in such a way as to reduce the cross sections of the teeth of the stator and rotor magnetic circuits, as well as the lengths of the magnetic flux paths in the backs of the magnetic circuits of the rotor and stator and, accordingly, provide the possibility of realizing the shaft 22 hollow, increased inner diameter. This, in turn, makes it possible to place a mechanical or hydraulic coupling or torsion bar 25, 26 inside the shaft.

The mechanical clutch is made non-disengaged movable. Mostly elastic or compensating. It is possible to use couplings with non-metallic elastic elements, for example, with rubber sprockets according to GOST 14084.

In some cases, including when it is necessary to limit onboard or wheel gears or traction motors from overload, it is possible to install hydraulic couplings. In the fluid coupling, the pump wheel is fixed on the rotor shaft of the traction motor, and the turbine wheel is mounted on the driven shaft. The working cavity of the fluid coupling is filled with liquid.

If a torsion bar is placed in the shaft cavity (springs in the form of a torsion shaft), this torsion bar is implemented with heads at its ends, usually with splines. Torsion heads, to ensure strength, are made with diameters exceeding the diameter of the main rod.

Based on the parameters of the existing couplings and torsion bars, the internal diameter of the hollow shaft, sufficient for their placement inside this shaft, is ensured if the product of the number of phases and the number of stator teeth is 36 or more. A traction motor or traction generator with a hollow shaft, the inner diameter of which is sufficient to accommodate a clutch or torsion inside it, can be implemented, in particular, three-phase with 12 or 18 teeth of the stator and 10 and 12 teeth of the rotor, i.e. with the specified work, respectively, 36 and 54.

Using a clutch or torsion bar 25, 26, depending on the implementation of the electromechanical transmission, the shaft of the traction motor or traction generator is connected, respectively, with a transmission device (for example, with an additional gearbox, cardan gear, an additional final drive mechanical clutch) or directly with the final drive as well as with an ICE matching device (a mechanical engine coupling, a multiplier, etc.) or directly with an internal combustion engine (with an engine crankshaft flywheel).

Normally closed electromagnetic parking brakes 27, 28, which are controlled directly by the main controller 9 or the traction motor controllers 11, 12, can be integrated into the traction motors 3, 4 or on-board gearboxes 7, 8. The controllers provide the inclusion of parking brakes to prevent the self-propelled machine from rolling downhill, as well as to brake and stop it, if for some reason the braking intensity of the traction motors 3, 4 is insufficient.

The generator controller (power rectifier) 10 provides the rectification of the output voltage of the traction generator 2, as well as the switching of the windings when it is in the electric motor mode when starting the engine and when the engine is braking the self-propelled machine. In the latter case, the controllers 11, 12 provide switching phase windings 20 of the traction motors 3, 4 when they are in generator mode.

The controllers 11 and 12 control the traction motors 3, 4 with the possibility of changing both the speed and direction of movement of the self-propelled machine. An alternative implementation of the machine’s transmission is the use of one traction electric motor, final drive and differential control device, or on-board friction clutches and service brakes.

The controls 14 are designed to generate transmission control signals and include at least one machine motion control device (joystick, steering wheel) connected to the main controller 9, the internal combustion engine start key, key and button switches, the fuel control handle, brake pedal and accelerator or decelerator.

The controller 9 is also connected to the operator panel 15, also referred to as the instrument panel, instrument cluster, display unit, information display unit, etc. It is made in the form of a set of electromechanical pointers, a graphic panel, light signaling devices, etc. and provides a display of the transmission parameters of the transmission and the machine as a whole, as well as the formation of alarm and warning signals for the operator. The operator panel 15 can be made in the form of a separate unit or combined with one of the controllers.

To control the operation parameters of the machine, including its transmission, its control system includes sensors 16. These include temperature and pressure sensors in the transmission and engine 1, sensors for longitudinal and transverse inclination of the machine (roll gauges), and the position of the machine (GPS signal receivers / GLONASS), the traction force of the machine, acceleration, angular velocities of the rotors of the traction electric motors 3, 4 and other sensors.

A separate controller (inverter, converter, switch) 11, 12 is installed for each traction motor. It is also possible to install several controllers on one traction motor when crushing power into sections of the stator of the electric motor or install a common controller on two traction electric motors.

Each controller (inverter, converter, switch) 11, 12 has a high-performance built-in microcontroller or digital signal processor that provides reception of control signals and direct digital control of electronic power switches made on IGBT transistors.

Controllers are connected by a local CAN network, LIN, etc. and receive control signals from the main (master, system) controller 9, directly from the controls 14 or from other devices of the transmission control system, depending on its design.

For the correct switching of phase windings of traction motors 3, 4, feedback on the position of the rotor is necessary. To fulfill this requirement, traction motors contain rotor position sensors, which are simultaneously used as sensors for their rotation speed. It is also possible to implement sensorless control algorithms for traction electric motors, in particular, based on flux linkage estimation.

The proposed electromechanical transmission of a self-propelled machine operates as follows.

The operator using the controls 14 sets the operating speed and direction of movement of the self-propelled machine.

ICE 1 directly or through a matching gear / multiplier drives the rotor of the traction generator 2. Its output voltage with the help of a power rectifier (generator controller) 10 is converted to DC voltage + Uc, -Uc on the power buses 17, which is supplied to the controllers 11, 12 traction motors 3, 4.

The controllers 11, 12 convert the DC voltage + Uc, -Uc of the power bus 17 into alternating voltage or into unipolar pulses of adjustable frequency and duty cycle supplied to the phase windings 20 of the traction motors 3, 4. The torque generated by the traction motors through couplings or torsions 25, 26 directly or via an additional transmission device is transmitted to final drives 5, 6 and further to drive sprockets 7, 8 and tracks of a self-propelled machine, as a result of which its movement is carried out in accordance with direction and speed selected by the operator.

If the power of ICE 1 is not enough to maintain the machine’s speed set by the operator at the current value of its traction force (resistance to movement), then regulation is carried out from the condition that the speed of the machine reaches the maximum possible in these conditions.

Algorithms for interconnected and automated transmission control are preliminarily determined by calculation or experimentally, recorded in the memory of controller 9 and then programmatically implemented by the microcontroller included in its composition.

When a self-propelled machine moves, couplings or torsion bars installed inside the hollow shafts of the traction electric motors and / or traction generator soften the dynamic loads, shocks and vibrations in the transmission, reduce or eliminate torsional vibrations of the connected shafts and parts, and compensate for misalignment of the rotor shafts of the traction electric motors and input side shafts or wheel gears, or the output shaft of the internal combustion engine, which ensures an increase in the service life of the transmission. At the same time, a reduction in fluctuations in the forces of interaction of the wheels or tracks of the self-propelled vehicle with the soil (soil) is ensured, which allows for increased smoothness of the self-propelled vehicle and its reduced technogenic impact on the soil. The achievement of this effect is due to the properties of the soil when exposed to cyclic loads, as well as the dependence of the maximum traction on the adhesion of the machine from its dispersion and slew rate.

If in the transmission of the self-propelled machine, in addition to the couplings or torsion bars in the hollow shafts of the electric machines, any additional damping or compensating devices are installed, for example mechanical elastic couplings at the output of the internal combustion engine and at the inputs of the side or wheel gears, their installation will lead to an improvement in the technical result, to achieve which the invention is directed.

For specialists in the art it is also clear that in addition to the described options for the electromechanical transmission of a self-propelled machine, other options for its implementation are also possible based on the features set forth in the claims.

Literature

1. BY 5907 U, B60K 17/00, B60L 11/00, 02/28/2010.

2. RU 2376158 C2, B60K 17/00, Н02Р 8/00, 12.20.2009.

Claims (8)

1. Electromechanical transmission of a self-propelled machine containing a traction generator, which is directly or via a matching device connected to an internal combustion engine (ICE) and adapted to convert at least a portion of the mechanical energy of the ICE to electrical energy, at least one traction motor adapted to convert electrical energy into mechanical, final drives or wheel reducers adapted to drive tracks or drive wheels of a self-propelled machine and connected by with at least one traction motor directly or via at least one transmission device, as well as a control system of at least one traction motor and / or traction generator, at least one of which is made of a reactive induction motor containing a stator with poles and phase windings, made in the form of lumped coils placed on the poles of the stator, and a rotor with a toothed magnetic circuit mounted on its shaft, moreover, to the rotor shaft of at least one traction electric motor If the brake is attached and / or the rotor shaft is hollow with the possibility of placing inside it an elastic or compensating mechanical coupling or hydraulic coupling, which is adapted to connect this shaft to the transmission device, or to the final drive, or to the wheel gear, or with a matching device, or with ICE. 2. Electromechanical transmission according to claim 1, characterized in that at least one traction electric motor and / or traction generator, the number of phases and the number of stator teeth are selected so that the result of their product is equal to or more than 36. 3. Electromechanical transmission according to claim 2, characterized in that at least one traction motor and / or traction generator is made three-phase with 18 stator teeth and 12 rotor teeth. 4. Electromechanical transmission according to claim 1, characterized in that the matching device, adapted to connect the traction generator with the internal combustion engine, is made in the form of a mechanical coupling of the engine and / or multiplier. 5. The electromechanical transmission according to claim 1, characterized in that the transmission device connecting the traction motor to the final or wheel gears contains a final drive, the outputs of which are connected to the final gears using the on-board friction clutches. 6. The electromechanical transmission according to claim 1, characterized in that the number of traction motors is set equal to the number of tracks or driving wheels of the self-propelled machine. 7. Electromechanical transmission according to claim 1, characterized in that the transmission device is made in the form of a matching gear, or input mechanical coupling of an onboard or wheel gear, or cardan transmission. 8. Electromechanical transmission according to claim 1, characterized in that the brake is made of electromagnetic disk and is suitable for use as a parking brake of a self-propelled machine.

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