DE102022001512A1 - Infinitely variable and constant-torque low-speed superimposed reversing gear with self-locking - Google Patents

Abstract

with a worm wheel fixed on a solid shaft stub in the interior of a hollow shaft, characterized in that

Description

The invention in the field of mechanical engineering relates to a continuously variable and torque-constant, low-speed and self-locking electromechanical speed superposition reversing gear with the features of the preamble of claim 1.

Superimposed speed gears are special gears which are usually used in light mechanical engineering when driving several machines with a single drive motor to adjust the speed of individual branches from the vertical shaft in order to increase or decrease the speed of the output shaft with positive or negative additional rotations. They are also used in control drives and during synchronization to change the drive phase position of the branches or the positioning and adjustment of rotation angles. In heavy mechanical engineering, these are also used as classic gears, e.g. B. used in shipbuilding and in wind turbines.

These superimposed speed gears are planetary gears whose outer ring or web can be rotated using a worm shaft.

However, since a planetary gearbox has numerous planetary gears and each meshing doubles the power loss caused by friction, which means that the bearings of the planetary gears are extremely heavily loaded, they are only suitable to a very limited extent as a speed superposition gearbox with the function of a continuously variable (reversing) gearbox in the low speed range and for high power and torque .

In addition, even the simplest conventional gears generate mechanical losses under constant load, which add up, especially in ship gears, which remain in the drive train during long cruises.

The same applies to hydraulic transmissions and also to so-called hybrid drives, in which a prime mover constantly drives a generator and this drives an electric motor via a frequency converter. This solution only makes sense in relatively high speed ranges due to the low electrical power losses on the frequency converters in this range because the losses grow with increasing shift of the voltage/frequency characteristic curve to low speeds and the higher the torque to be developed, the more complex the control becomes becomes. These low speed ranges, which are the most difficult to control in terms of control technology, require special adaptations of the converters to the voltage/frequency characteristic in the partial load range and also technical adaptations of the motors.

In this respect, it is not efficient to operate high-performance electric motors in the lower speed range.

After all, there is no simple and relatively loss-free and wear-free device in the prior art for the stepless and permanently frictional speed change without backlash in the form of a summation or distribution gear for the low speed range at high torques and powers.

The invention is therefore based on the object of providing an uncomplicated speed superposition gear for low speeds and permanently high torques, which, outside of the speed change, couples the drive shaft to the output shaft in a non-positive and lossless manner and, if necessary, is able to both increase and increase the speed until the direction of rotation is reversed without backlash.

Furthermore, drive machines of all types should be able to be operated at the optimal operating point and therefore most economically, regardless of the load, with the highest degree of efficiency or at the nominal speed and nominal torque.

Since various applications require higher speeds than correspond to the nominal speeds of large diesel engines in particular, there is also a requirement to easily increase the speed of the output shaft of the speed superimposition gearbox.

Furthermore, the device according to the invention, as a summing or distribution gear, should enable both a speed-adapted auxiliary drive and several auxiliary drives with different speeds.

All of these tasks are solved by a device with the features of claim 1 and by a device with features 2 - 10.

Advantageous embodiments of the invention are specified in the dependent claims.

The device according to the invention fulfills this purpose by means of a design as a superimposed speed transmission with axes aligned with one another, axes laterally offset from one another and a design as part of a Control circuit consisting of speed superimposition gear and drive machine.

The device according to the invention basically consists of a worm wheel fixed on a solid shaft stub, enclosed by a funnel-shaped hollow shaft, in the interior of which a worm/motor combination is attached. This consists of a worm which is attached to an axle, both ends of which merge into the drive axles of the two motors, which in turn are fixed inside or outside on the hollow shaft.

This means that the solid shaft and the hollow shaft are mechanically connected in a torsionally rigid and non-positive manner by the worm so that they can be fully loaded. However, the rotation of the worm can cause the hollow shaft to rotate faster or slower depending on the direction of rotation, which is superimposed on the speed of the solid shaft.

There is therefore no input through a third shaft mounted fixed to the frame, such as. B. in the planetary speed superimposition gearbox, but the input takes place directly on the hollow shaft by means of the two motors attached to it, driving the hollow shaft relative to the stationary or rotating solid shaft.

These worm/motor combinations are ideally arranged in four numbers in opposite positions around the worm wheel for optimal load and weight distribution and to avoid imbalance.

The most advantageous motors used are electric motors whose energy is supplied either through a brush/slip ring combination on the hollow shaft or within the hollow shaft with feed at the shaft end.

Inputs in the same direction through the screw/motor combination on the hollow shaft increase the speed of the hollow shaft and inputs in opposite directions reduce the speed of the hollow shaft, while the speed of the solid shaft remains the same.

When one shaft is at a standstill, the speed and direction of rotation of the other shaft is determined exclusively by the screw/motor combination, which is preferably designed as electric motors that can be controlled by a frequency converter.

In contrast to the conventional planetary speed superposition gear, however, in the device according to the invention, when the screw/motor combination is at a standstill, the drive and output shafts function as a continuous solid shaft and transmit the mechanical power flow completely without loss.

1. 1. Die Antriebswelle dreht, die Schnecken/Motor-Kombination steht still, damit dreht die Abtriebswelle synchron starr mit der Antriebswelle - normale Marschfahrt.
2. 2. Die Antriebswelle dreht, die Schnecken/Motor-Kombination überträgt gleichsinnig die gleiche Drehzahl, damit dreht die Abtriebswelle sich gleichsinnig und doppelt so schnell wie die Antriebswelle - schnelle Marschfahrt.
3. 3. Die Antriebswelle dreht, die Schnecken/Motor-Kombination überträgt gegensinnig die halbe Drehzahl der Antriebswelle, damit dreht sich die Abtriebswelle halb so schnell wie die Antriebswelle - Langsamfahrt.
4. 4. Die Antriebswelle dreht, die Schnecken/Motor-Kombination überträgt gegensinnig die gleiche Drehzahl der Antriebswelle, damit steht die Abtriebswelle still - Stopp.
5. 5. Die Antriebswelle dreht, die Schnecken/Motor-Kombination überträgt gegensinnig die doppelte Drehzahl der Antriebswelle, damit dreht sich die Abtriebswelle gegensinnig und halb so schnell wie die Antriebswelle - Rückwärtsfahrt.
6. 6. Die Abtriebswelle ist blockiert, die Schnecken/Motor-Kombination dreht, damit dreht die Antriebswelle synchron starr mit der Schnecken/Motor-Kombination - Anlassen der Schiffsdieselmaschine.

Given a given direction of rotation and speed of the drive shaft, depending on the direction of rotation and speed of the screw/motor combination, various operating cases arise for the drive and output shafts, which can be most clearly represented by their effect on a ship's drive:

1. 1. The drive shaft rotates, the screw/motor combination stands still, so the output shaft rotates synchronously with the drive shaft - normal cruising speed.
2. 2. The drive shaft rotates, the screw/motor combination transmits the same speed in the same direction, so the output shaft rotates in the same direction and twice as fast as the drive shaft - fast cruising speed.
3. 3. The drive shaft rotates, the screw/motor combination transmits half the speed of the drive shaft in opposite directions, so the output shaft rotates half as fast as the drive shaft - slow travel.
4. 4. The drive shaft rotates, the screw/motor combination transmits the same speed of the drive shaft in opposite directions, so the output shaft stands still - stop.
5. 5. The drive shaft rotates, the screw/motor combination transmits twice the speed of the drive shaft in opposite directions, so the output shaft rotates in the opposite direction and half as fast as the drive shaft - reverse travel.
6. 6. The output shaft is blocked, the screw/motor combination rotates, so the drive shaft rotates rigidly in synchronization with the screw/motor combination - starting the marine diesel engine.

Due to the continuous speed adjustment of the screw/motor combination, any intermediate speed level is possible, meaning that the rotation of the output axis can be continuously increased, reduced, brought to zero and reversed at a constant speed of the drive axis.

Conversely, with the device according to the invention, a constant speed can also be obtained from a variable vertical shaft speed, although it basically does not matter whether it is a matter of power reductions, i.e. outputs, or power supplies, i.e. inputs.

Depending on the intended use, there are different designs of the device according to the invention, all of which are listed below Two different operating modes called “individual operation” (screw/motor combination controlled arbitrarily) or “closed-loop operation” (screw/motor combination controlled by feedback) can be operated, whereby in principle it does not matter which of the axes, hollow shaft or solid shaft, is the drive or output axis act.

1. Speed superposition gearbox with aligned axes

This basic form of solid and hollow shaft with worm/motor combination is characterized by the fact that the main drive power flow of the drive shaft takes place directly in a straight extension of the drive shaft when interposed in a drive train to change the speed ( 1 and 2 ).

2. Speed superimposition gearbox with solid shafts offset laterally parallel to each other

2.1. Here the hollow shaft is separated from the adjoining solid shaft and this is closed into a flywheel-like housing, using the larger diameter of the hollow shaft to provide a simple translation and a changed torque with spur gears for the main drive via external teeth and the pinion of the driving or driving machine. to achieve power flow ( 3 , machine not shown).

3.2. Speed superposition gearbox for power take-off or input drives

3.2.1. This design basically follows 3 enables one or more auxiliary drives or inputs, with the pinions of the other machines (not shown) engaging in the external teeth of the disk-shaped housing.
Because the worm wheel is not fixed on the solid shaft but is attached to the housing on the solid shaft in grooves so that it can be moved, clutch operation at standstill is also possible ( 4 ) by sliding the housing along the solid shaft.
Another embodiment, not shown, represents the output through an axis at right angles to the main shaft, which engages with its bevel gear in the teeth of the bevel gear ring located on the front side of the hollow shaft. This design corresponds to half a differential gear, with the horizontal axis being designed as a hollow shaft with a ring gear.

3.2.2. Here, the shortened hollow shaft, which is mounted fixed to the frame, is also used to equip any diameter with a gear ring in order to achieve a specific reduction ratio in combination with a specific pinion diameter ( 5 ).

This can be expanded to the effect that continuously stepped toothed rings of smaller diameter are attached to the entire funnel-shaped part of the hollow shaft, so that the gear ratios can be changed as desired when the shaft is at a standstill (not shown).

4. Speed superposition gearbox as part of a control loop consisting of speed superposition gearbox and drive machine.

The speed change takes place in any operating state by activating the screw/motor combination, whereby the adjustable speed range is initially limited by the power of the total of 4 motors in the screw/motor combination.

However, this process of initially changing the nominal speed of the drive machine only represents the manipulated variable of a closed control loop of a drive system ( 6 ) which consists of the device according to the invention and the mechanical or electrical speed adjuster of the drive machine.

Because as soon as, in the case of drive by the solid shaft, the screw/motor combination relieves or loads the hollow shaft in the power flow, the speed of the drive machine also increases or decreases accordingly, whereby the drive machine is returned to the nominal speed via a feedback control device.

This means that the electric motors are gradually relieved of the load, after which this control process can be repeated as often as desired in any direction of rotation until the drive machine rotates at idle and the output shaft either runs or stands still or the drive machine rotates the output shaft under full load. In this case, the process is completely lossless because the torsionally rigid coupling does not cause any friction losses and the motors of the screw/motor combination are out of operation ( 6 ).

The control circuit described consists of the speed adjustment of the drive machine and a speed controller on an electromechanical basis with a hydraulically operated actuator ( 6 ) which affects the speed adjustment of the drive machine. The speed controller consists of a threaded spindle that is electrically driven at the nominal speed and on which a spindle nut is driven in opposite directions to the actual speed when the speed differs accordingly Threaded spindle moves and acts as an actuator on the speed adjuster of the drive machine via a hydraulic cylinder.

Advantages of the invention

1. 1. The device according to the invention works continuously as a transmission and reduction gear and in particular delivers a constant torque at low speeds even in reversing mode, which in principle cannot be achieved by converter-fed electric motors. This generally enables a flexible-speed and constant-torque drive for rolling mill and metallurgical machines which require slow movements with large forces and both reversing and self-locking. It is also suitable for earthmoving machines that require high torque at relatively low speeds, such as wheel loaders and bulldozers, but also for extremely heavy special vehicles such as those used in opencast mining to transport bulk materials. The device according to the invention is also suitable for driving heavy locomotives.
2. 2. When changing the direction of rotation, thanks to the worm drives, there is no wear-intensive backlash of the drive and output shafts, but the change of direction is always fully frictional, which means that the device according to the invention is particularly suitable for change gears in earthmoving machines.
3. 3. The transmitted torque is determined by the diameter of the hollow shaft and remains constant at all speeds, with the worm drives ensuring that the gear is self-locking to the greatest possible extent, which represents a lossless continuous drive and a backup in the event of tensile loads in the event of the drive failing.
4. 4. The device according to the invention is also suitable as a clutch which allows power transmission with maximum torque under full load at any low speed without any wear.
5. 5. The device according to the invention enables the drive machine to be started using electrical energy and thus makes both the usual compressors and wind tanks and a separate starting machine unnecessary.
6. 6. The space requirement is relatively small and is aligned with the input and output shafts, which is a great advantage for use in vehicles and ships.
7. 7. The device according to the invention is particularly suitable for ship drives in that it enables the engine to operate continuously at the technically and economically most advantageous operating point and direct power transmission through the torsionally rigid coupling.
8. 8. Outside of the change in speed, the torsionally rigid coupling of the input and output shafts through the device according to the invention has the great advantage that the mechanical losses that are inevitable when conventional ship gears are constantly running are completely avoided. In view of the fact that the cruise has by far the largest share in the movement of a ship, this is of enormous economic importance since the entire drive train can be designed for direct drive by the diesel engine, which runs in the most economical range.
9. 9. The hollow shaft or the housing with its large diameters and its external teeth allow it to be used as a simple and therefore relatively loss-free reduction gear, which means that drive machines with higher nominal speeds can also be used. With optimal adaptation of the nominal drive motor speed and the machine being driven, the absence of an intermediate gear enables lossless power transmission.
10. 10. The transmission according to the invention replaces both the reversing of an internal combustion engine necessary for reversing and the reverse gear of an intermediate transmission; moreover, it is subject to only little wear because it is inactive when the power is transmitted at full speed and is only used when the speed changes and reversing.
11. 11. With a suitable design of the drive machine in coordination with the superposition gearbox according to the invention, the energy consumption and wear of an internal combustion engine fall to a minimum point within a narrow operating range, which in turn corresponds to the highest economic efficiency of operation. In this respect, a drive train can be designed for maximum economical operation by appropriately defining the engine data and the properties of the speed superimposition gearbox according to the invention.
12. 12. The device according to the invention takes over the task of starting internal combustion engines when the output shaft is blocked and thus replaces the compressed air system usually required for this purpose.
13. 13. If the drive fails, the device according to the invention enables an emergency drive at any speed as long as electrical energy is available.

The invention is explained in more detail below with reference to the drawings.

1 shows a vertically opened side view - on the end of the drive axle (1) there is a worm wheel (2) attached into which a worm/motor combination, consisting of an axle (3) with a worm (4) in the middle position and a drive motor (5 ) intervenes at one end. The motors (5) are each attached to a console (7) within the funnel-like hollow shaft (6). The console (7) is not shown in the following figures.

This simple construction represents the basic form of the device according to the invention in which it does not matter which shaft is the drive shaft and which shaft is the output shaft.

The energy is supplied to the motors (5) either through transfer lines attached to the outside of the hollow shaft (6) or through a channel within the solid axle (1). Since the diameters of the worm wheel (2) and hollow shaft (6) do not change, the transmitted torque also remains constant.

However, due to the worm drive, the technically sensible maximum speed is limited compared to spur gears and is therefore particularly suitable for low-speed power transmissions with high and constant torque.

2 shows a vertically opened side view looking from the drive side with the worm wheel (2) and four worm/motor combinations, each consisting of the axle (3), the worm (4) and the motor (5) as well as the drive shaft (1) . The motors can also be mounted outside the hollow shaft (6).

3 shows a vertically opened side view of the design for the additional translation of the output main shaft, with the worm wheel (2) with the worm/motor combination on the solid shaft (1) instead of the hollow shaft (6) now sitting in a housing (8) which by means of the two running bearings (9) are rotatably mounted on the continuous solid axle (1).

To transmit power, there is an external toothing (10) on the housing (8) into which a spur gear (11) engages with the offset output shaft (12).

4 shows the design as a vertically opened side view 3 for drives or inputs of or through other machines with speeds that deviate from the drive shaft.

For the purpose of disengaging during standstill, the superposition gear according to the invention can be displaced in the grooves (13) of the solid shaft (1).

5 shows another modification as a vertical side view 3 which has an internal toothing (14) in addition to the external toothing (10) on the annular part of the hollow shaft (6).

Furthermore, on the hollow shaft (6), which is fixed to the frame in the pivot bearing (15), there is a further external toothing (16) of freely selectable diameter, via which a further force input or output can take place (not shown).

6 shows schematically the electromechanical speed control with a hydraulically operated actuator, which essentially consists of a threaded spindle (17) which is driven by an electric motor (18) with a constant speed as a controlled variable. There is a spindle nut (19) on the threaded spindle (17), which is connected to the output shaft of the diesel engine (21) by means of a gear (20). On the left side of the spindle nut (19) there is a thrust bearing (22) to which the sleeve (23) connects, which rests on the piston (24) in the cylinder (25).

The rotation of the threaded spindle (17) and the opposite rotation of the spindle nut (19) are superimposed in such a way that the spindle nut (19) stands still at the same rotational speeds. If the diesel engine (21) now rotates the spindle nut (19) higher or lower than the electric motor (18) as a result of loading or unloading, it moves on the threaded spindle (17) towards or away from the cylinder (25) and thereby pushes it Piston (24) into the cylinder (25) or pulls it out, with which the hydraulic oil synchronously regulates the speed of the diesel engine down or up via a second hydraulic cylinder (not shown here) on the injection pump (26).

The 7 shows schematically the structure of a ship drive as an exemplary embodiment of the device according to the invention.

The speed superposition gear (27) according to the invention with external teeth (10) rotates the propeller shaft (28) with the propeller (29) via the spur gear (11) and is connected on the drive side via a clutch (30) to the diesel engine (21), which in turn coupled to the generator (32) via the clutch (30) and the gearbox (31).

The nominal speed of the diesel engine is ideally set so that, after reduction via the inactive speed superposition gear (27) according to the invention, it corresponds to the cruise speed of the propeller shaft, so that the usually multi-stage intermediate gear is eliminated and when driving slowly, the device according to the invention reduces the speed of the propeller shaft (28) to Zero and if necessary until reversal.

The electrical energy required for this is supplied by a suitable electrical energy storage device (33), which is charged via the generator (32) if necessary.

This means that in the event of partial or complete failure of the diesel engine, the propeller shaft can also be driven by the device according to the invention; if the propeller shaft is blocked, the device according to the invention serves as a starter.

In contrast to the usual travel control by the machine telegraph, which normally controls the speed of the diesel engine for all speeds, in the device according to the invention the diesel engine runs constantly at the nominal speed and the travel control is carried out exclusively via an actuator (34) in the machine telegraph which via a frequency converter (35) controls the speed of the speed superimposition gear (27) according to the invention.

The nominal speed of the diesel engine is ensured by the electromechanical speed control (36) with a hydraulically operated actuator, into which the diesel engine speed is fed via the output (37) and the control pulses are transmitted hydraulically to the injection pump (38).

If you want to go from cruise to slow speed, the device according to the invention drives the propeller shaft in opposite directions - this relieves the load on the diesel engine and therefore rotates at a higher speed, which, however, is reduced by a suitable control device, if necessary until the engine is idling without load and the Propeller shaft stands still or rotates backwards due to further increased speed of the device according to the invention.

Reference symbol list

1

Full wave

2

worm wheel

3

Screw/motor combination

4

Snail

5

engine

6

hollow shaft

7

console

8th

Housing

9

Running bearing

10

External gearing

11

gear

12

output shaft

13

grooves

14

Internal gearing

15

Axle bearing

16

External teeth on hollow shaft

17

threaded spindle

18

Electric motor

19

spindle nut

20

Gears

21

Diesel engine

22

Thrust bearing

23

sleeve

24

Pistons

25

cylinder

26

Injection pump

27

Speed superimposition gearbox according to the invention

28

propeller shaft

29

propeller

30

clutch

31

transmission

32

generator

33

Electrical energy storage

34

Actuator in the machine telegraph

35

frequency converter

36

Electromechanical speed control with hydraulically operated actuator

37

downforce

38

Injection pump

Claims (10)

with a worm wheel fixed on a solid shaft stub in the interior of a hollow shaft , characterized in that the worm wheel is toothed with at least one worm that sits firmly on a transverse axis which 2.1. firmly connected at both ends to the wall of the hollow shaft using axle bearings 2.2. is designed at least at one end as a drive axle of a motor 2.3. which can be activated variable speed in both directions of rotation by 2.4. it receives its controlled energy supply via the hollow shaft or wirelessly 2.5. which uses energy stored within the hollow shaft and the motors are controlled wirelessly from outside and that the motor is designed as an electric motor 3.1. the transverse axle is equipped with a motor at each end 3.2. the combination of transverse axis and motors is arranged in multiple versions on the circumference of the worm wheel within the hollow shaft and that the hollow shaft at its annular opening 4.1. an external or internal toothing on the circumference for an output parallel to the axis 4.2. is equipped with a bevel gear ring on the front side for an output perpendicular to the hollow shaft. and that the hollow shaft tapers towards the solid shaft in a funnel shape at any circumferential radius an external toothing carrying a bevel gear rim and that the hollow shaft 7.1. which is designed as a disk-shaped housing 7.1.1. which encloses the worm wheel, worm and axle with motors 7.1.2. freely rotatable on a solid shaft 7.1.3. with external teeth 7.1.4. equipped with a bevel gear ring 7.1.5. stored on the solid shaft in multiple versions 7.1.6. is freely rotatable on a first solid shaft stub and that the pinion or bevel gear of the second solid shaft stub engages in the teeth 8.1. has a specific diameter for a specific reduction ratio 8.2. the worm wheel with the housing is displaceably arranged in grooves on the solid shaft and that the worm wheel/motor combination forms a control loop together with an internal combustion engine 9.1. the speed of the drive machine is kept constant by its speed controller set to the nominal speed 9.2. The drive machine is returned to the set nominal speed through electronic feedback of the speed 9.3. an electromechanical control device is returned to the set nominal speed 9.4. wherein the electromechanical control device consists of a spindle which is driven by a motor with a constant speed corresponding to the drive machine speed, the spindle nut being coupled to the machine shaft which is connected to the speed adjuster of the drive machine by means of a linkage or hydraulic pressure system.

Images