A rotating hydrostatic transmission

Description

Field of technique

The range of application of the invention is applications and proceedings where you want to continuously control and regulate the power in and split in various continuous ratio of the power to the two ends of a shaft/rotor or from a certain power in to one of the two shafts of a shaft/rotor or to the shaft/rotor want regulate the ratio of velocity speed and torque of power out from the shaft/rotor or to one of the two ends of the shaft/rotor.

It means it could be used in a drive chain between a combustion motor, as a shaft to or integrated in a rotor in an extra electrical motor/generator, and in the out going drive shaft on a vehicle.

When it's used in that way it could be used to add power as well as take care of lost energy at braking.

It means it could be direct integrated as a rotor in an electrical motor/generator into a driveshaft to get torque vectoring as well.

Torque vectoring means control the torque individually between right and left side of the drive shaft. Torque vectoring also means an effective way to take care of the different torques on the wheels when you brake the vehicle and transferring back energy.

It means it could be used as a shaft or rotor to/in an generator to control and regulate the velocity speed and torque in to the generator with a better usable ratio than in of the velocity speed and torque for power out from the generator. An example is in windmills.

The advantages are less total weight, compact and less mechanical losses and hydraulic losses than operation of devices today for the same type of application.

The position of the technique today

Today there is three main propulsion and regenerating concepts of electrical vehicles and hybrid vehicles.

The first one is done by two motors on one drive shaft or more and energized from a battery or capacitor or a generator (Figure 1.1 and 1.2).

The second and the simplest concept the propulsion is done just by an electrical motor replacing the normal combustion engine or being an extra motor in the drive chain with gearbox and differential to one or two drive axels (Figure 1.3). The third one is a technique where you let the wheel motors or the single motor concept be replaced by hydraulic motors driven from the electrical motor by a pump with variable displacement.

The steering is done by turning one or two or even more pair of wheels.

To day there are also vehicles with only one shaft and two electrical motors at each wheel.

The shaft is both a drive shaft and a steering shaft.

There are driving and steering in other vehicles as well, but with more than one wheel shaft, for example lawn mowers and special trucks.

In wind mills today you have a mechanical gearbox or hydrostatic transmission in front of the generator to get the desired torque and velocity speed in to the generator. There are even mechanisms to adjust the angel of the blade of propeller.

To day when an electrical motor is used in a hybrid vehicles in the drive chain between a combustion motor and the drive shaft to add power and to take care of lost energy at lowering the speed they use a mechanical solution. They technique to control and regulate is by a planetary gearbox design.

Solved problems

The suggested concept/invention integrated in the drive shaft, see Figurel .4 to 1.6, can replace the two motor concepts with one smaller motor per drive shaft and the one motor concept the differential and the differential lock function.

In the two motor concept it means, less weight due to a need of a smaller motor and less one power control units, less weight at the wheels, compactness and probably less demand of energy out of less weight and lower total cost. The cost advantage will probably increase at more power.

In the one motor concept it means a mechanical differential less and the already existing differential lock function, less mechanical friction losses when there is less gears involved, less weight and more compactness and probably energy and lower cost.

In the generator concept you will be able to control the velocity speed of the generator in a compact way, probably at less losses due to less mechanical technique and more optimized generator, lower total weight due to less mechanical technique and smaller electrical devices, and together lower cost. The cost advantage will probably increase at more power.

The description above describes how the concept/invention differs to known applications and the problem/disadvantages it solves but not to known other techniques. There is other known techniques, but not yet seen in use as practical applications. The invention could be seen or called "a rotating hydrostatic transmission where the regulation of power in to the shaft/rotor, and split out to the two shaft ends and the regulation of the ratio velocity speed/torque out of shaft/rotor are controlled in an outside wireless contacted master controller. It's a long sentence but it's a summary of the invention.

One known technique is mentioned in patent EP 0481022 A 1 "Hydraulic differential in an electrical motor". It contains similar parts and technique but the technique to control the dynamics of the device or put in a system, the problems of a rotating tank, to pressurize the accumulator and where to put the filter and to solve the problem of leakage differs and are in some extent not practically solved or shown.

Nor are the use and the problems solved when it's integrated in a generator mentioned. Those are some characteristics that differ between my claims and the known technique/patent/ above.

Another known technique similar to one used here in this concept/invention is the one in patent se 529678 C2 where is mentioned how to transfer signals and power with a specific pulse modulation over an air gap. In my concept/invention the claims contains techniques to use the variable pulse width at variable frequencies. That is not mentioned there.

A variable pulse width at variable frequencies in comparison with variable pulse width at fixed frequency create an advantage due to they won't be variation in power. That's one more problem solved.

List of Figures

Figure 1 shows different motor concepts for propulsion and steering.

Figure 2 shows a circuit diagram of a hydrostatic transmission in a "closed circuit-closed loop hydrostatic system"

Figure 3 shows a circuit diagram for a hydrostatic transmission, a "closed loop and closed circuit with variable displacement motors/pumps" and two check valves and a special accumulator.

Figure 4 shows input and out put to and from the over all controller/processor in a schematic over all control and regulating process.

Figure 5 shows a hydrostatic transmission in a rotor of symmetrical axis

with axial piston pumps/motors with adjustable displacement. Figure 6 shows a block diagram of frequency modulated wireless control of the split of power into and in a rotor.

Figure 7 shows different types of coils

Figure 8 shows the special accumulator

Figure 9 shows the circuit diagram from Figure 3 added to with an electrical charge pump and relief valve.

Detailed description of the invention

The suggested invention characterized by a master controller/processor function for controlling and regulating a hydrostatic transmission in a shaft/rotor to or in an electrical motor or generator. The job for master controller function which is situated outside the shaft/rotor is to control and regulate from the outside adjustable incoming power or the one from the shaft/stator delivered.

The same master controller/processor even controls/regulates the split of the power to the two ends of the shaft/rotor or when the power comes in it controls and take care of the not adjusted power in at the two ends of the shaft/rotor by controlling/regulating the split of velocity speed and torque ratio.

The hydrostatic transmissions in a shaft/rotor or in an electrical motor or generator consist of a pair of axial pumps and motors with adjustable displacement mechanical bolted "back to back". Not really physically"back to back", inlet and outlet connection between them separate them. That separation is designed out of a need of a space or a room there for other small necessary devises as valves, tank/accumulators, filter, electronics, servo functions and a little more, mention later.

The outer case of the hydrostatic transmission forms the outer shell of the shaft or rotor. It could be further stabilized in a tube. An abbreviation for hydrostatic transmission is HST. The "input" to the master controller/processor is the parameters as the torque (current) and speed of velocity of the electrical motor or generator and rotation direction. Another "input" is the "Active' desired/wished position/tilt angel of the swash plates (7) in the HST from for example a person, see Figure 5. Even other outside input could be involved, like a gyro. The swash plates in the HST then control the torque of the two outgoing shafts (2) (5) by adjusting the adjustable displacement in the pumps and motors with adjustable displacement. A directional valve, 4 ways-2 positions, between the pumps and the motor in the HST can even change the direction of flow of oil.

The master controller/processor function and the power supply into the shaft/rotor are done wireless.

The HST with adjustable displacement of the pumps and motors is a" closed circuit-closed loop hydrostatic system". It means the hydraulic system had to be filled up with oil, the leakage is important to control. The adjustable displacement of the pump and motors need to be controlled and regulated.

When the HST rotates it will be an extra problem with inner leakage. On the other hand the external leakage at the two outgoing shafts (2) (5) wouldn't be any big problem by using good sealing' s there.

The internal leakage from the pressure side at every revolution the flow circulates in the system will be in need of taking care of otherwise a disturbing "lost motion" in the torque transfer will occur. The invention has solved the problems with the leakage, "lost of motion" and the risk of cavitations on the low pressure side and not to forget, the invention will need a tank which manages to work without leakage when it rotates.

The solution is primarily a special tank/accumulator together with two check valves and a relief valves, see Figure 3 pos 1, it can be more than one tank/accumulator and one relief valve. Secondly the solution is the prior one plus a charge pump and relief valve after the tank/accumulator and before the check valves, see Figure 9 pos 14. That's when relief of pressure in the transmission case/drain is necessary when more pressure is needed in tank/accumulator than the pressure in the transmission chase permits. The power to the electrical driven charge pumps comes from on of the transfer of power over the coils at one of the ends of the two shafts and possible to switch "on" by the master controller/processor. The special tank/accumulator, see Figure 8, consist of connection (12), a cylinder (8), a low friction sealed piston (9). The piston is easily moveable to be able to take care of variations in the closed systems volume and to create by a compression spring (10) a force to overcome friction and to keep/maintain a specific necessary inner pressure. When this specific inner pressure is higher than a bar on the back side of the check valves one of the two check valves will open and replenish lost flow and prevent cavitations there. The distance the piston can travel is limit. That is utilized in such a way, when very high pressure occurs it limits the travel distance. At the end it allows the oil to enter out through drilled holes (12) at the end of the accumulator. It means it works like a relief valve as well. When that occur and even when some leakage oil is lost from the closed circuit by some leakage oil between the piston and the cylinder it is caught up by an extra tank (1 1) designed like a balloon fetch behind. The balloon had to be made of oil resistant rubber.

The characteristic of the spring, spring constant, had to be flack. Long movements will increase the force from the string. A big tank is an advantage. One way to increase the practical volume of the accumulator is to allow and arrange so whole free room between the pumps and the motor be a tank.

The shaft/rotor consist of two back to back connected axial piston pumps/motors (3) (5) in a closed circuit-closed loop. The displacement of the axial pumps and motors is adjusted by the tilt/angel of the swash plates (7). The tilt/angel of a swash plate is individually adjusted by a slave controller or CMOS logic by their own and its algorithm and assisted by their own servo system inside but controlled/coordinated (getting the desired/wished tilt/angel) from outside by the master controller. The inside slave controller or CMOS logic works/acts out of the difference between the desired/wished tilt/angel of its swash plate and the actual tilt/angel. The servo system could work out of an electro hydraulic one or an electric actuators, electromagnets or a small electrical motor with gearbox, which actually do the force and movement to the swash plate.

The desired/wished value and actual value correspond to active width of the individual pulse incoming and with constant or variable frequencies. In a pulse trains there will be the same. The pulses transferred to the shaft/rotor signals with the desired/wished value can also be seen as a signal transfer. It's coming in/transferred wireless to the shaft/rotor, see more about it below.

The transfer to the shaft/rotor of necessary power for the logic, the servo systems and for other systems like the charge pump and flow directional valve, is done by utilizing the energy in the pulse width (Watts). The variation of the height of the amplitude above, say 5V, the one needed for signal transfer mentioned in the part above even called "on" is a function used for voltage control like a switch with "on" and "off The height of the amplitude at "off is equal to the amplitude just above and needed for signal transfer. For example that's a function utilized to control the "on" and "off of the directional valve, to control the direction of the flow. The transfer is done wireless to the shaft/rotor by induction from DC pulses from a fixed primary coil to a secondary coil; see Figure 7, fixed to the shaft/rotor in concentric position to each other and very close to each other to create as little as possible of leak inductance. One way of doing it is by a Flyback topology, compare the technique in patent SE 529678 C2. A difference here in this claim is that it's done by frequency modulation; it means the width of the wave is modulated / variable. It's the width of the active part of the wave the pulse which is used as the desired/wished value and the start of that pulse triggers the start of the pulse with the actual value. In discrete periods of time the slave controller/CMOS logic calculates/comparing the differences in width and then regulates the start and stop of the servo function until the difference is zero. See Figure 6.

There is sometimes a demand to change the direction of the fluid between the pumps and the motors. To avoid pass "through" zero angel of the swash plates which can be tricky, one uses a directional valve , 4 ways- 2 positions, controlled by a solenoid and the "on" and "off function mentioned above, transferred from one side of the two shafts. The other one could be utilized by an electrical charge pump. See Figure 6.

The master controller/processor and the rotating HST with its slave controller I will call a system. The master controller/processor and function needs program with algorithms. The verb of the master controller/processor function is to coordinate/match the "input parameters" to be "output parameters". The "input" to the master controller/processor is the parameters like torque (current) and speed of velocity of the electrical motor or generator and rotation direction. Another "input" is the 'Active' desired/ wished position/tilt angel of the swash plates (7) in the HST from for example a person, see Figure 5. It could be 'fictive' desired/wished position/tilt angel of the swash plates due to desired/wished request of new driving direction, to turn left, please accelerate, brake and the actual values of the torque of the motor, speed of velocity, Even other outside input could be involved, like a gyro. There are some no real actual values, like the actual position/angel of the swash plates back to the master controller. They are indirect values. The desired/whished values had to be the actual values. The actual values are not hard linked to the wished as it could be a delay or not correspond to the desired/wished, but that's the way the controller have to work in it's final output.

The slip of one wheel and an algorithm in the master controller/processor to adjust it could be a function by the torque vectoring ability. The warning here would be from an actual value as the power in and a gyro. Output is the torque, velocity speed and the direction of the rotation motion and the desired/whished value of the angel of the two swash plates and some "on" or "off signal. These are examples of functions in applications the master controller/processor can control by the facilities in this invention and how it works. This is summarized/described in Figure 4 In a wind mill may have another whished behavior, the desired/wished ratio of velocity speed and torque should perhaps be adjusted so the incoming power is delivered at a very constant velocity of speed. That's another function in applications where the master controller/processor can control by the facilities in this invention.

Detailed description of the transfer of regulated power and control signals wireless by frequency modulated pulses, Figure 6.

A voltage controller fed from a DC -source called VI can shift the potential on the pulse to primary coil LI via a MOSFET Ml . The shift of the potential to two different levels of the pulse height to the primary coil LI is done due to what potential is desired out of coil L2. An example could be to shift from 12 Volt to 8 Volt. The technique for that could be a Step down controller.

The "cutting" of the potential into pulses or pulse trains after MOSFET Ml is done by a frequency modulator, a PWM where you vary the frequency and at the same time the pulse width

The primary coil LI is supplied current and stores energy while the MOSFET Ml is turned on. The winding direction of the secondary coil and the polarity of the diode Dl are such that no current will be transferred while the MOSFET Ml is turned on. The total time between until the MOSFET Ml turn on, is called the cycle time and is variable out of the variable frequency and so the part (the width of the pulse) of the cycle time the MOSFET Ml leads. The later is called the active part (pulse) of the cycle time. The active part (pulse) is a constant part of the cycle time, for example 0.5. The ratio is called the duty- cycle. The cycle time vary for example +- 10-20%.

According to Lenz law there is a back e.m.f built up in secondary coil L2 during the time the MOSFET Ml is turned on but it changes immediately direction when the primary coil no longer is supplied by current. The diode D now turns on. It means a current is supplied via Dl and is "flattened" by the capacitor C2 and now usable as a DC, for example of 8 V or 12 V. In figure 6 it feeds the solenoid of a hydraulic valve. The voltage/potential out on coil L2 is depended of the ratio of turns of the LI coil and the L2 coil. For example if the number of turns of coil LI is 6 and the L2 are 12 it will increase the voltage from 6V to 12V. The way how the LI and L2 winding are wrapped around the core is important. It had to be according to Figure 6. Notice that one end of each coil is marked with the same time.

The power for the slave controller/logics and servo and the variable power to for example the solenoid of the directional valve is transferred wireless to the shaft/stator inductively by a DC current by utilizing the energy in the pulse, The variable power is done by vary the height of the amplitude of the pulse. It's earlier called "voltage control" or "on" and "off.

It could be for example to control a directional valve with a solenoid, that's a way to shift the direction of the flow in a hydraulic system. When the voltage is shifted/decreased from 12V to 8V to the solenoid the ratio of the amplitude is shifted 12/8 and the 12V rated solenoid change the position of the piston in the valve to an other position.

Different width of the pulse is utilized as different signals, for example of different value of desired/wished position /angel of the swash plate.

A drop of voltage is done before the Dl . The amplitude of the pulse is stabilized by zener diodes to say 5V. The positive ramp of the pulse together with a RC circuit creates a voltage peak which is used as a start trigger. This trigger also starts an internal pulse which by its actual width represents an actual value of the position/angel of the swash plate. By comparing these in controller/CMOS logics and when there is a difference the controller/CMOS logics order/command the servo function to adjust the difference to nil. A little hysterias round nil is to be desired. Page 4

Figure 7 shows different shape the DC coils for wireless transfer of variable power and signals/information. The shape is important to minimize the leakage inductance at the transfer.