DE102015111928A1 - planetary gear - Google Patents

Abstract

Planetary gear (1) having a ring gear (18), a first drive shaft (2) on which a first sun gear (6) is fixed, which is in operative connection with the ring gear (18) via first planet gears (10), a second drive shaft (4) on which a second sun gear (8) is fixed, which is in operative connection with the ring gear (18) via second planet gears (12), wherein the first planet gears (10) and the second planet gears (12) on a common planet carrier (16) are arranged, wherein a portion of the second shaft (4) coaxially within the first shaft (2) is arranged, a first electric machine (32) which is connected to the first drive shaft (2), a second electric machine ( 34), which is connected to the second drive shaft (4), and a control device (40), which is connected to the two electric machines (32, 34) and is adapted to the electric machines (32, 34) in a first Operating mode, unsp to operate and clamped in a second operating mode.

Description

Field of the invention

The invention relates to a planetary gear and a method for operating a planetary gear.

State of the art

From the prior art it is known to use so-called braced gears in order to obtain the least possible play. So that beats DE 603 01 648 T2 ago, to let act multiple drives on an output element. The drive shafts of the drives can be coupled together and braced against each other to achieve a low clearance on the output.

However, the arrangement known from the above-mentioned patent is comparatively large and heavy, so that in some applications mounting problems may arise.

Disclosure of the invention

The object of the invention is to improve known from the prior art transmission, in particular, it is an object of the invention to provide a transmission with little or adjustable game, in particular to zero, high rigidity and compact design. Ideally, a transmission according to the invention is also able to transmit high torques. Furthermore, a low-cost production would be desirable.

The object is achieved with a planetary gear with the features of claim 1. Independent subject of the invention is also a method for operating such a planetary gear. Inventive drives according to the subordinate claims comprise a planetary gear according to the invention.

A first aspect of the invention relates to a planetary gear with a ring gear, a first drive shaft on which a first sun gear is fixed, which is operatively connected to the ring gear via first planet gears, a second drive shaft on which a second sun gear is fixed, which is fixed to the Ring gear is operatively connected via second planet gears, wherein the first planet gears and the second planetary gears are arranged on a common planet carrier, wherein a portion of the second shaft is disposed coaxially within the first shaft, a first electric machine which is connected to the first drive shaft, a second electric machine, which is connected to the second drive shaft, and a control device, which is connected to the two electric machines and is arranged to operate the electric machines in a first operating mode unstrained and braced in a second operating mode operate.

Planetary gears show a particularly good efficiency and are therefore suitable for strained operation, without being operated excessive losses. Planetary gears have low breakaway torques. In addition, planetary gears have a high rigidity. Contrary to the basic expectation that planetary gears are unsuitable due to their generally not backlash-free design for completely backlash-free drives, it has been possible with the invention based on planetary gears with their advantages to construct a backlash-free drive.

In typical embodiments, at least one sun gear or the sun gears are each made in one piece with the respective drive shaft. In further embodiments, the sun gear and the drive shaft are designed as separate components, which are for example pressed or connected by means of a welded connection or a knurled connection.

The planetary transmission according to the invention typically provides that two drive shafts are each arranged at least partially within a ring gear and in each case are in operative connection with the ring gear. The ring gear is typically circular and typically includes at least one internal ring gear. The term ring gear in this application is typically understood to mean that the ring gear may also be fixedly connected to the housing or itself forms the housing. About the operative connection of the two drive shafts on the planetary gears with the ring gear a tension of the two drive shafts is possible, so that a drive with a small clearance can be created.

In typical embodiments, the ring gear is formed integrally. One-piece ring gears are stiff or can allow easy installation. In other embodiments, the ring gear is formed with at least two parts. In this way, under certain circumstances easily two different toothing geometries for the first planetary gears and the second planetary gears can be created, for example, in first and second planetary gears with different diameters.

Typically, first planetary gears are arranged between the first drive shaft with the first sun gear and the ring gear, via which the first drive shaft with the ring gear in Active compound is. Typically, second planetary gears are arranged between the second drive shaft with the second sun gear and the ring gear, via which the first drive shaft is in operative connection with the ring gear. The first and the second planet gears may have an identical structure. In embodiments, the first and the second planet gears are designed differently, for example, with different diameters or different widths.

Different width planet gears, where "width" denotes the axial extent, can be used to use one of the two drive shafts, for example the first drive shaft, as the main drive shaft. In the example, the first planet gears would then be wider than the second planet gears. The second drive shaft could then be used to ensure backlash, for example, by applying a low braking torque to the drive power of the first drive shaft. In other embodiments, the second planet gears are wider, so that the second drive shaft can be used as the main drive shaft.

In typical embodiments, the first sun gear and the second sun gear have different widths, for example, planet gears of different widths. In typical embodiments, the width of the first sun gear corresponds at least substantially to the width of the first planetary gears and / or the width of the second sun gear corresponds at least substantially to the width of the second planetary gears.

Different diameters can be used to account for geometric constraints or to create different gear ratios. Identical diameters can offer the advantage of a simple structure and can lead to more identical parts.

Typically, the two drive shafts are each driven by an electric machine. Typically, the planetary gear comprises a control device which is connected to the two electrical machines and is arranged to operate the electric machines in a first operating mode unstrained and clamped in a second operating mode. This offers the advantage that in a first operating mode, a position can be approached quickly and in a second operating mode as in a tense operation, a particularly accurate machining or positioning is possible because errors due to play in the transmission can be avoided. The drive with two electric machines and a planetary gear in an embodiment according to the invention has the advantage that a master / slave configuration can be created, with a bracing of the transmission is possible. In the master / slave configuration or the master / slave operating mode, one of the two electric machines is operated slightly delayed relative to the other electric machine, so that one of the two electric machines drives and the other electric machine remains opposite to the drive of the first electric machine and this slows down. In this operating mode, a tensioning of the drive shafts is possible, resulting in a low clearance and a high rigidity of the planetary gear.

In typical embodiments of the invention, it is possible to operate the two electric machines in the operating mode for clamping and also to operate the electric machines in another operating mode, in which the two drive shafts are operated in the same direction unstressed, for example, a quick start to allow a position in a machine tool or to generate a high torque.

Typically, the first drive shaft is at least partially disposed within the second drive shaft. This offers the advantage of an extremely compact design. In addition, it is possible in this way to organize the drive from one side of the planetary gear and provide on the other side in the axial direction of the output. In particularly preferred embodiments, the first and second drive shafts are hollow, with one partially received within the other. Within the inner drive shaft cables can be made in this arrangement.

In typical embodiments, a common stator is provided for both electrical machines. In typical embodiments with a stator, a mechanical tension can be provided, which acts on one of the two drive shafts and which can be activated and deactivated by the control device in order to enable strained and unrestrained operation. This can offer the advantage of a simple construction. In further typical embodiments, at least one stator is present per electric machine, that is, for example, a first stator and a second stator. This can offer the advantage of better controllability.

In typical embodiments, the first electric machine has a first rotor and the second electric machine has a second rotor. The first rotor is typically in operative connection with the first drive shaft or is fixedly mounted on this. Of the second rotor is typically in operative connection with the second drive shaft or is fixedly mounted on this.

In typical embodiments, the first rotor and the second rotor are the same size. In further embodiments, the first rotor and the second rotor have different sizes. For example, the rotors have different diameters and / or have different widths. Rotors having different widths may, in typical embodiments, have identical diameters, for example, to cooperate with stators of identical diameter or with a common stator. Different width rotors can offer advantages, for example in connection with planet wheels of different widths. In each case, the first rotor and the first planetary gears cooperating with the first rotor are each wider or narrower than the second rotor and the second planetary gears cooperating with the second rotor. Different width rotors can be used to use one of the two electric machines and the corresponding drive shaft, for example the first electric machine and the first drive shaft, as the main drive. The second drive shaft and the second electric machine could then be used in this example to ensure backlash, for example, by applying a low braking torque to the drive power of the first drive shaft. In other typical embodiments, the ratio is reversed. Typical embodiments may also use identical rotors or planet gears, for example to increase the number of identical parts.

In preferred embodiments of the invention, at least one of the electrical machines or a stator of an electrical machine is at least partially disposed within a circumference of the ring gear or the stator or stators have an outer circumference which is smaller than or equal to an outer circumference of the ring gear. In further embodiments, a common stator of the electrical machines is at least partially disposed within the circumference of the ring gear.

In further typical embodiments of the invention, at least one of the electrical machines is at least partially disposed radially outside the ring gear. In a drive via spur gears of the drive shafts or at least one of the drive shafts, a transmission or drive is provided with a very small axial extent.

Preferably, at least one of the electric machines or both electric machines are arranged coaxially with the ring gear. In typical type embodiments, the electric machines have a circumference equal to or smaller than the circumference of the ring gear. In other typical embodiments, the ring gear or the housing integrally formed with the ring gear carrier at least from a stator of the electric machines.

Typically, the rotors of the electric machines are arranged on the drive shafts. In further embodiments, an intermediate stage between the electric machine and the respective drive shaft is provided, for example to provide an additional ratio.

Typically, the ring gear is fixed in place and / or an output fixed to the planet carriers is connected. In typical embodiments, the ring gear may be attached to a housing of the planetary gear. In further typical embodiments, the ring gear is used as output and the planet carrier of the first and second planetary gears are fixed in place.

Another aspect of the invention relates to a method of operating one of the typical planetary gear trains described herein, comprising: driving the two electric machines to unrestrainedly drive the two drive shafts in a first mode of operation; and driving the two electric machines so that they braced the two drive shafts in a second mode of operation.

In typical embodiments, the electrical machines are operated in the second mode of operation with a phase shift. The control device is typically set up to operate the electrical machines with a phase shift, for example in the second operating mode, and / or without phase shifting, for example in the first operating mode. A phase shift in embodiments offers the advantage that a strained operation of the electrical machines is reliably possible by simple means. In embodiments, the control of the two servomotors via servo controller with a master / slave control.

Short description of the drawing

Preferred embodiments and particular embodiments of the invention will be explained in more detail with reference to the following figures.

1 shows an embodiment of a planetary gear in a schematic sectional view.

Description of preferred embodiments

In the description of sectional views of the figures, it should be noted that the respective sectional views partially each represent only a part of the planetary gear. The omitted in the drawing half is constructed substantially mirror-inverted or has no further significant details relative to the page shown.

In the 1 is schematically a planetary gear 1 according to typical embodiment of the invention. The invention is not on the in the 1 rather, the scope of the invention is determined by the claims. In particular, in numerous features, which in the embodiment of the 1 Variations or alternatives as described herein are possible as far as they are within the scope of the claims.

The planetary gear 1 includes a first drive shaft 2 and a second drive shaft 4 , With the first drive shaft 1 integrally formed is a first sun gear 6 , as well as with the second drive shaft 4 a second sun gear 8th is integrally formed.

The first sun wheel 6 acts with first planet wheels 10 together, the second sun wheel 8th with second planet wheels 12 interacts. One of the first planetary gears 10 and one of the second planet gears 12 are on a single planetary pin 14 , which is in a planet carrier 16 stored, stored. From the planet wheels 10 and 12 in each case only one planetary gear is shown, the other planetary gears, in typical embodiments, a total of 3, 4 or 5 or 6 first planetary gears and 3, 4, 5 or 6 second planetary gears are evenly distributed over the circumference of the planet carrier. This division is well known for a simple set planet gears from known planetary gears.

The planet wheels 10 and 12 each combed together outside in a ring gear 18 , The planet wheels 10 and 12 have identical diameters, but different widths. So are the second planetary gears 12 narrower than the first planet wheels 10 and accordingly, the second sun gear is also 8th narrower than the first sun wheel 6 ,

In typical embodiments, the first planetary gears have a different width from the second planetary gears. Typically, the first sun gear may have a different width than the second sun gear. In this way it is possible to transmit different sized torques on the two branches, for example, in the example of 1 the first drive shaft 2 with the first sun gear 6 and the first planet wheels 10 which are wider than the second planetary gears 12 to be used as a main drivetrain. The strand over the second drive shaft 4 with the second sun gear 6 and the second planet wheels 12 which are narrower can be used to play the planetary gear 1 be influenced by a tense or by an unstrained operation, whereby the game can be minimized or completely excluded by a tense operation.

The planet carrier 16 is integral with an output 20 executed, on which, for example, a further shaft can be attached. This is a blind hole 22 with thread in the output 20 intended.

In typical embodiments, the output is made in one piece with the planet carrier. This should also be covered by the term "fixed connected". In further embodiments, the output is connected, for example via a screw or a connection with bolts to the planet carrier.

In other embodiments, separate planet carriers are provided for the first planetary gears and the second planetary gears. This can simplify storage of the planet gears. Typically, separate planetary carriers are interconnected in such a way that relative rotation of the two planetary carriers relative to each other about the axis of the planetary gear is prevented. In this way, with simple standard planet carriers a tense operation can be achieved.

The ring gear 18 is integral with a housing part 24 the housing of the planetary gear 1 executed. With the one-piece design of a housing part of the housing with the ring gear of the planetary gear, a particularly simple structure can be achieved.

In typical embodiments such as that in US Pat 1 shown planetary gear planet carrier is constructed zweiwangig. This offers the advantage that, in particular in connection with two arranged on a planetary pinion planetary gears, only comparatively small deformations occur.

The two-wheeled planet carrier 16 of the planetary gearbox 1 is like in typical embodiments in areas between the planetary gears 10 and 12 equipped with connecting bolts, which are the two cheeks of planet carrier 16 connect. Through the sectional view of 1 the connecting bolts are not shown.

The planetary gear 1 has a first electric machine 32 and a second electric machine 34 , The first electric machine 32 has a first stator 36 and the second electric machine via a second stator 38 , The stators 36 and 38 can be controlled separately from each other by a control device 40 , The control device 40 supplies the electrical machines 32 and 34 more precisely the stators 36 and 38 over a cable 42 with electrical energy. This is due to the structure of the control device and the cable 42 a separate control of the stators 36 and 38 possible.

The first electric machine 32 includes a first rotor 44 and the second electric machine 34 includes a second rotor 46 , The first rotor 44 is pushed onto the first drive shaft and connected to this for torque transmission by a toothing. Likewise, the second rotor 46 on the second drive shaft 4 deferred and connected to this for torque transmission by a toothing.

Between the first rotor 44 and the second rotor 46 or even in typical embodiments between a first drive shaft and a second drive shaft, it is sufficient in embodiments to provide only a plastic bearing, such as that between the first rotor 44 and the second rotor 46 arranged ring 48 ,

The relative movements between the first drive shaft and the second drive shaft or between the first rotor and the second rotor are very small in typical embodiments, since only minor movements are needed to allow a tension of the planetary gear. On the other hand, typical embodiments are antifriction-free between the first drive shaft and / or the first rotor on the one hand and the second drive shaft and / or the second rotor on the other hand. Typical bearings in this area are slide bearings or plastic rings. In further embodiments, rolling bearings are provided between the rotors or the drive shafts.

The first rotor 44 and the second rotor 46 are each with permanent magnets 50 and 52 equipped. The permanent magnets 50 and 52 interact with the stators 36 and 38 and cause the torque development of the electric machines 32 and 34 when energizing the stators 36 and 38 ,

In further embodiments, rotors are provided with electromagnets, or it can be provided a common stator and a clamping can be achieved by a mechanical brake of one of the rotors or one of the drive shafts.

The control device 40 is furnished to the two electric machines 32 and 34 energized in phase or with a phase shift. When the electric machines are energized 32 and 34 with the same phase position in a first operating state results in substantially little difference from a conventional combination of an electric machine with a planetary gear. However, this does not necessarily apply to other operating states, in particular a strained operation of the planetary gear.

Furthermore, the control device 40 set up the electrical machines 32 and 34 operate in a second operating state with a phase shift. In this way it can be achieved that the second electric machine 34 for example, slightly the first electric machine 32 "Trailing", ie a drive torque of the first electric machine 32 slows. In this way, it comes through the common stored planet gears 10 and 12 to a tension of the two drive shafts 2 and 4 to each other and thus to extinguishing the game between the planetary gears 10 . 12 , the sun wheels 6 and 8th and the ring gear 18 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 60301648 T2 [0002]

Claims (10)

Planetary gear ( 1 ), with - a ring gear ( 18 ), - a first drive shaft ( 2 ) on which a first sun gear ( 6 ) is fixed, which with the ring gear ( 18 ) via first planet gears ( 10 ) is in operative connection, - a second drive shaft ( 4 ) on which a second sun gear ( 8th ) is fixed, which with the ring gear ( 18 ) via second planet gears ( 12 ) is in operative connection, - wherein the first planetary gears ( 10 ) and the second planetary gears ( 12 ) on a common planet carrier ( 16 ) are arranged, - wherein a portion of the second wave ( 4 ) coaxially within the first wave ( 2 ), - a first electric machine ( 32 ), which with the first drive shaft ( 2 ), - a second electric machine ( 34 ), which with the second drive shaft ( 4 ), and - a control device ( 40 ) with the two electrical machines ( 32 . 34 ) and is adapted to the electrical machines ( 32 . 34 ) operated in a first operating mode unstrained and clamped in a second operating mode to operate. Planetary gear ( 1 ) according to claim 1, wherein the first planet gears ( 10 ) have the same diameter as the second planetary gears ( 12 ). Planetary gear ( 1 ) according to claim 1 or 2, wherein the first sun gear ( 6 ) has the same diameter as the second sun gear ( 8th ). Planetary gear ( 1 ) according to one of the preceding claims, wherein the ring gear ( 18 ) is integrally formed. Planetary gear ( 1 ) according to any one of the preceding claims, wherein the first sun gear ( 6 ) and / or the first planet gears ( 10 ) each have a different width from the second sun gear ( 8th ) and / or the second planet gears ( 12 ) exhibit. Planetary gear ( 1 ) according to one of the preceding claims, wherein the first electric machine comprises a first rotor and the second electric machine comprises a second rotor, and wherein the first rotor has a different width from the second rotor. Planetary gear ( 1 ) according to one of the preceding claims, wherein the electrical machines ( 32 . 34 ) at least one stator (whose outer diameter is not greater than an outer diameter of the ring gear ( 18 ). Planetary gear ( 1 ) according to one of the preceding claims, wherein the ring gear ( 18 ) is fixed in place and / or where an output ( 20 ) fixed to the planet carrier ( 16 ) connected is. Method for operating a planetary gear ( 1 ) according to one of the preceding claims, comprising: - driving the two electric machines ( 32 . 34 ), so that they unstrained the two drive shafts ( 3 . 4 ) in a first mode of operation; and - driving the two electrical machines ( 32 . 34 ), so that it braces the two drive shafts ( 3 . 4 ) in a second mode of operation. Method according to claim 9, wherein the electrical machines ( 32 . 34 ) are operated in the second operating mode with a phase shift.

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