DRIVE SYSTEM WITH PLANETARY GEARBOX

Description

[0001] The invention relates to a drive system with planetary gears.

[0002] It is generally known that a drive system with planetary gears is feasible.

[0003] From DE 10 2017 115 479 A1, a temperature determination on a superimposed gearbox is known.

[0004] A gearbox with an output torque sensor is known from DE 10 2017 102 108 A1.

[0005] A kit for a series of geared motors is known from DE 103 12 941 A1.

[0006] A wind turbine is known from US patent 2008 / 0279686A1, which includes at least one gearbox.

[0007] A device for energy recovery from a gearbox is known from US patent 2012 / 0156034A1.

[0008] A planetary gear is known from EP 3 081 831 A1.

[0009] From the US 10 454 347 B2 The closest known state of the art is a torque sensor arrangement.

[0010] From the EP 3 081 831 A1 A planetary gear system is known.

[0011] The invention is therefore based on the objective of further developing a drive system with planetary gears, whereby the operational reliability is to be improved.

[0012] According to the invention, the problem is solved in the drive system according to the features specified in claim 1.

[0013] Important features of the invention in the drive system with planetary gears are that the planetary gears have a two-sided planet carrier, wherein the planet carrier has a first cheek, a second cheek and webs, wherein the webs connect the first cheek to the second cheek, in particular wherein the webs are spaced apart from each other in the circumferential direction to the axis of rotation of the planet carrier, in particular uniformly spaced from each other, wherein a sensor for detecting values ​​of a physical quantity is attached to the planet carrier, in particular wherein the physical quantity is a change in length, a deformation, a strain or a torsion of the planet carrier, in particular of one of the webs of the planet carrier, and / or wherein the sensor has at least one strain gauge.

[0014] The advantage here is increased operational reliability, as the planetary gear can be monitored directly by the sensor, allowing for immediate detection of any failure. This is because the planet carrier is the output-side part of the planetary gear, making any failure easily detectable.

[0015] According to the inventionThe first cheek, particularly on its side facing away from the second cheek, has a blind hole, wherein, particularly on its end face and / or on the side of the first cheek facing away from the second cheek, the first cheek has radially extending recesses that open into the blind hole and extend to the radially outer surface of the first cheek. An advantage of this is that a simple housing volume for the transmitter module and the circuit board with signal electronics can be provided. Furthermore, material is saved, thus reducing the moment of inertia, particularly to enable higher dynamics of the drive system.

[0016] In an advantageous embodiment, the planet carrier is formed in one piece, in particular in one part, from the first cheek, the second cheek and the bridges, In particular, wherein the webs are arranged axially, i.e., parallel to the direction of the axis of rotation of the planet carrier, between the first cheek and the second cheek, and in particular, wherein the webs are spaced apart from each other circumferentially. In particular, wherein the planet carrier is made of metal. An advantage of this is that simple manufacturing is possible.

[0017] In an advantageous embodiment, the bore axis of the blind hole is aligned parallel to the axial direction, in particular parallel to the axis of rotation of the planet carrier. An advantage of this is that the planet carrier remains balanced, especially despite the installation of a transmitter module.

[0018] In an advantageous embodiment, the blind hole is aligned coaxially with the planet carrier and / or the sun gear of the planetary gearbox. An advantage of this is that the planet carrier is balanced and can therefore be operated at high speeds, especially despite the installation of a transmitter module.

[0019] In an advantageous embodiment, the planet carrier has an axial bore extending through the first cheek, which is aligned coaxially with the blind hole, wherein the clear inner diameter of the axial bore is smaller, in particular at least ten times smaller, than the clear inner diameter of the blind hole. It is advantageous that a cable can be routed from the webs through the axial bore and thus to the circuit board with the transmitter module. In particular, this is made possible centrally within the planet carrier, thus ensuring that the planet carrier remains optimally balanced.

[0020] In an advantageous embodiment, the sensor is attached to one of the webs, in particular by adhesive, and in particular, the sensor is arranged on a flat surface section of the web or on the radially outer surface of the web, which in particular resembles a section of the lateral surface of a circular cylinder. It is advantageous that the torque transmitted through the webs is easily detectable, in particular by means of the deformations to which the web and thus also its surface are subjected. While a very good signal-to-noise ratio can be achieved if the sensor is arranged as far radially outward as possible, the radially outer surface is curved, making it difficult to attach the sensor, in particular a strain gauge. The inner sides of the webs, however, have flat surfaces on which a sensor can be easily attached.

[0021] In an advantageous embodiment, a printed circuit board is arranged in the blind hole, particularly at the bottom of the blind hole, with an electrical conductor leading from the printed circuit board through the axial bore to the sensor. The advantage here is that the evaluation of the sensor signals is simple and can be carried out close to the sensor.

[0022] In an advantageous embodiment, a transmitter module is arranged in the blind hole bore, which is configured such that the transmitter module emits electromagnetic waves, in particular radio waves, and / or that the transmitter module transmits the values ​​detected by the sensor by means of electromagnetic waves, in particular radio waves, especially according to the Bluetooth or WLAN standard. It is advantageous that the sensor signals or the information obtained from the evaluated sensor signals can be transmitted contactlessly to a stationary evaluation unit.

[0023] In an advantageous embodiment, the recesses are designed as grooves, in particular radial grooves. This is advantageous because it allows for simple manufacturing and, although the sensor module is surrounded by metal and arranged almost in a Faraday cage, the recesses allow electromagnetic radiation to escape, thus enabling communication between the signal electronics located on the rotating part (i.e., the planet carrier) and the stationary evaluation unit, which is located, in particular, outside the housing.

[0024] In an advantageous embodiment, the cross-section of the recesses is constant, i.e., independent of the radial distance to the axis of rotation of the planet carrier. This is advantageous because it allows for simple manufacturing, since the planet carrier is made of metal, particularly steel.

[0025] In an alternative advantageous embodiment, the cross-section of the recesses increases proportionally to the radial distance from the axis of rotation of the planet carrier. This is advantageous because the mass of the planet carrier, and therefore its moment of inertia, is minimized.

[0026] In an advantageous embodiment, an antenna is arranged on the inside of the housing part or the ring gear of the planetary gear, particularly for receiving the electromagnetic waves emitted by the transmitter module, and especially wherein the antenna is connected to an evaluation unit by means of a connecting cable, which is passed through a bore through the housing part. An advantage of this is that a space-saving position for the antenna is provided. Preferably, the antenna is arranged in a rigid plastic part and / or encapsulated. This allows for secure mounting.

[0027] In a preferred embodiment, planetary gears are mounted in the planet carrier, on which planetary gears are rotatably mounted, in particular via needle bearings fitted onto the planetary gears. These gears mesh with both the ring gear and the sun gear. The advantage of this design is that a cost-effective planetary gear set can be manufactured.

[0028] In a preferred embodiment, the circuit board and / or the transmitter module are arranged in a plastic housing, which is positioned and / or inserted into the blind hole. The advantage here is that simple and secure mounting is achievable.

[0029] In an advantageous embodiment, the planet carrier is rotatably mounted by means of a first bearing and a second bearing. wherein the inner ring of the first bearing is mounted on the second web, wherein the outer ring of the first bearing is received in the housing part and is positioned against a ring gear or a radially inwardly projecting collar that receives the ring gear, wherein the inner ring of the second bearing is mounted on the second web and positioned against a step of the second web, wherein the outer ring of the second bearing is received in the housing part and is positioned against a ring gear or a radially inwardly projecting collar that receives the ring gear, and wherein a shaft nut screwed onto a threaded area of ​​the second web presses against the inner ring of the first bearing. It is advantageous that the planet carrier can be used as the driven part of the planetary gear and, according to the invention, can be provided for monitoring the function of the planet carrier.

[0030] In an advantageous embodiment, a shaft seal is incorporated in the housing part and seals against the first web. An advantage of this design is that the antenna can be positioned outside the oil-filled interior and the bearings of the planetary carrier are oil-lubricated.

[0031] In an advantageous embodiment, the area covered by the blind hole in the axial direction includes the area covered by the radially directed recesses, in particular radial grooves, in the axial direction. The advantage here is that the electromagnetic radiation can exit directly radially, and thus the antenna can be arranged in the axial area covered by the recesses.

[0032] In an advantageous embodiment, an evaluation unit is arranged on the planetary gear, particularly on the housing part of the planetary gear, which is connected to an antenna located on the inside of the housing part, especially for receiving the electromagnetic waves emitted by the transmitter module and passing through the recesses. An advantage of this is that the sensor signals can be used to monitor the gear and thus the drive system, thereby increasing operational reliability.

[0033] Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0034] The invention will now be explained in more detail with reference to schematic illustrations: In the Figure 1 A cross-section of a planetary gear system according to the invention is shown.

[0035] In the Figure 2 Figure 1 shows an oblique view of a planet carrier 10 of the planetary gear from a first viewing direction.

[0036] In the Figure 3 An oblique view of the planet carrier 10 of the planetary gear is shown from a second viewing direction.

[0037] In the Figure 4 A top view of planet carrier 10 is shown.

[0038] In the Figure 5 A cross-section of planet carrier 10 is shown.

[0039] As shown in the figures, a sun gear is non-rotatably connected to the driving shaft 5 and engages with planet gears which are rotatably mounted on planet bolts 4 and engage with a ring gear 1 which is designed as a housing part of the gearbox or is non-rotatably connected to a housing part of the gearbox.

[0040] The planetary bolts 4 are incorporated into the planetary carrier 10, which is designed as a two-sided planetary carrier.

[0041] The planet carrier 10 has a first cheek 21 and a second cheek 20, which are connected by circumferentially spaced webs 22. Preferably, the planet carrier 10 is made in one piece, in particular as a single unit, especially including the first cheek 21, the second cheek 20 and the webs 22.

[0042] Each of the planetary bolts 4 is both inserted through a bore in the second cheek 20 and into a bore, in particular a blind hole-like bore, in the first cheek 21.

[0043] The planet carrier 10 has a centrally located blind hole 8 in its first cheek 21. The axis of the blind hole 8 is aligned coaxially with the axis of rotation of the planet carrier 10.

[0044] The planet carrier 10 is mounted in the housing part of the gearbox via a first and a second bearing (2, 11).

[0045] The inner ring of the first bearing 2 is placed on the second cheek 20 and axially limited by a shaft nut 3 screwed onto a threaded area of ​​the second cheek 20.

[0046] The outer ring of the first bearing 2 is received in the housing part and positioned against the ring gear 1 or a radially inward projecting collar that receives the ring gear 1.

[0047] Likewise, the outer ring of the second bearing 11, in particular on the side of the ring gear 1 facing away axially from the first bearing 2, is positioned against the ring gear 1 or a flange projecting radially inwards and receiving the ring gear 1.

[0048] The inner ring of the second bearing 11 is placed on the first cheek 21 and positioned against a step formed on the first cheek 21.

[0049] Thus, the bearing tension can be adjusted by tightening the shaft nut 3. However, the clamping forces are also transmitted via the webs 22.

[0050] To monitor and determine the deformation of the planet carrier 10, at least one sensor, in particular strain gauges, is attached to one of the webs 22.

[0051] The webs 22 each have a radially outer surface, in particular an outer cylindrical shape, which serves as a sensor surface, i.e. as a surface suitable for attaching the sensor.

[0052] Alternatively or additionally, flat surface sections of the webs 22 are also suitable as sensor surfaces. Preferably, each web 22 has a surface that is flat at the front and rear in the circumferential direction and that has only a single circumferential angular position, i.e., extends only in the radial and axial directions. Furthermore, this flat surface is preferably finely machined so that it is optimally suited as a sensor surface.

[0053] The first cheek 21 has a continuous axial bore 6 in the center of the blind hole bore 8, through which an electrical connecting line leads from the sensor into the blind hole bore to a circuit board 7, which is arranged in the blind hole bore 8, in particular at the bottom of the blind hole bore.

[0054] This circuit board 7 is electrically connected, in particular by plug connection, to a transmitter module 9. Preferably this is designed as a Bluetooth transmitter or WLAN transmitter.

[0055] The first cheek 21 is designed on its end face as a flange block interface 30, so that a machine part driven by the planetary gearbox, in particular a robot part, can be screwed to it. For this purpose, axially oriented bores 32 are provided on the end face of the first cheek 21, which are each arranged at the same radial distance to the axis of rotation of the planet carrier 10 and are spaced apart from each other in the circumferential direction, in particular uniformly spaced from each other.

[0056] The machine part to be driven therefore covers the front face of the first cheek 21 and is preferably made of metal.

[0057] The planet carrier 10 is made of metal.

[0058] The electromagnetic radiation emitted by the transmitter module 9 exits the blind bore 8 via radially oriented recesses 31 arranged on the end face of the first cheek 21. These recesses are spaced apart from one another in the circumferential direction, and in particular, are spaced at a uniform distance from one another. The recesses 31 are preferably designed as grooves with a constant cross-section. Alternatively, the recesses 31 can also be designed with a cross-section that increases proportionally to the radial spacing.

[0059] The transmitter module 9 and the signal electronics arranged on the circuit board 7 can be supplied by an energy storage device arranged in the blind hole 8, in particular on the circuit board 7. Preferably a battery is used as the energy storage device.

[0060] An evaluation unit is located on or outside the planetary gearbox and electrically connected to an antenna located inside the gearbox. For this purpose, a through-hole is provided in the housing through which an electrical connection cable is routed, connecting the antenna to the evaluation unit.

[0061] The area covered by the blind bore 8 in the axial direction includes the area covered by the radially directed recesses 31, in particular radial grooves, in the axial direction. Thus, even if the blind bore 8 is covered at its end face by a driven part, the emission of electromagnetic radiation from the transmitting module 9 is still possible.

[0062] The recesses 31 open radially inwards into the blind bore on one side and radially outwards into the interior of the gearbox on the other.

[0063] In the axial direction, the recesses 31 are arranged on the side of a shaft seal facing away from the bearings (2, 11), which is received in the housing part and seals towards the planet carrier 10.

[0064] The cheeks (20, 21) can also be referred to as cheek parts (20, 21).

[0065] An additional energy storage device 12, in particular a battery, is arranged in the blind hole 8, from which the transmitter module 9 and the signal electronics mounted on the circuit board 7 can be supplied.

[0066] In further embodiments according to the invention, an electromagnetic wave train is radiated via the antenna, which is received by the transmitting module 9 and uses the energy of the received signal to electrically power the signal electronics and the transmitting module 9. In particular, the energy storage device can thus be implemented as a double-layer capacitor and be rechargeable, so that the power radiated by the transmitting module 9 as well as the power consumption of the transmitting module 9 and the signal electronics are available.

[0067] In further embodiments of the invention, signal electronics are supplied from a loss energy source. For example, a Peltier element or an element operating according to the Seebeck effect is arranged on the planet carrier 10, or a piezoelectric element, so that electrical energy can be obtained from a heat flow and / or structure-borne sound.

[0068] In further embodiments of the invention, the signal electronics are supplied with electrical energy without contact by means of a ring winding attached to the outer circumference of the first web 21, which is aligned coaxially to the axis of rotation of the planet carrier 10 and is inductively coupled to a stationary second ring winding. In particular, this second ring winding is attached to the inside of the housing part of the gearbox or to the ring gear 1. Preferably, the second ring winding is aligned coaxially to the first ring winding.

[0069] In further embodiments of the invention, a different sensor type is used instead of strain gauges, such as an OFW sensor, in particular a surface acoustic wave sensor. Here, it is advantageous to design the sensor surface to be flat. The OFW sensor preferably operates with radar frequencies, wherein a piezoelectric area is applied to a semiconductor chip, which excites an acoustic surface wave that is reflected back to the piezoelectric area by reflectors arranged on the chip and thereby converted back into a radar frequency. Thus, by evaluating the response signal following a query signal, the stress on the sensor surface and the temperature of the sensor surface can be determined.

[0070] In further embodiments of the invention, the radially through recesses 31 are not designed as grooves, but as bores, in particular radial bores in the first cheek 21. Thus, the recesses 31 can be designed simply, cost-effectively and without interfering with the driven part. Reference symbol list

[0071] 1 Ring gear 2 First bearing 3 Shaft nut 4 Planet bolt 5 Driving shaft 6 Through axial bore 7 Circuit board 8 Blind hole, especially axially oriented 9 Transmitter module 10 Planet carrier 11 Second bearing 12 Energy storage device, especially battery 20 Second web 21 First web 22 Web 30 Flange block interface 31 Radially oriented recesses 32 Bores

Claims

1. A drive system with a planetary gear unit, wherein the planetary gear unit has a pinion cage (10) with two side pieces, wherein the pinion cage has a first side piece (21), a second side piece (20) and lands (22), wherein the lands connect the first side piece to the second side piece, wherein a sensor for acquiring values of a physical variable is fastened to the pinion cage, wherein the first side piece has a blind bore (8), wherein the first side piece (21) has radially extending cutouts (31), characterised in that the cutouts (31) are embodied radially uninterrupted through the first side piece and which open into the blind bore (8) and extend up to the radially outer surface of the first side piece (21).

2. A drive system according to claim 1, characterised in that the pinion cage is formed in one piece from the first side piece, the second side piece and the lands.

3. A drive system according to one of the preceding claims, characterised in that the bore axis of the blind bore is oriented parallel to the axial direction.

4. A drive system according to one of the preceding claims, characterised in that the pinion cage has an axial bore which passes through the first side piece and which is oriented coaxially with the blind bore, the clear internal diameter of the axial bore being smaller than the clear internal diameter of the blind bore.

5. A drive system according to one of the preceding claims, characterised in that the sensor is fastened to one of the lands.

6. A drive system according to one of the preceding claims, characterised in that a printed circuit board is arranged in the blind bore, with an electric line being guided from the printed circuit board (7) through the axial bore to the sensor.

7. A drive system according to one of the preceding claims, characterised in that an emitter module (9) is arranged in the blind bore, which emitter module is embodied suitably such that the emitter module emits electromagnetic waves and that the emitter module emits the values acquired by the sensor by means of electromagnetic waves.

8. A drive system according to one of the preceding claims, characterised in that the cutouts are embodied as grooves, and / or in that the cutouts are embodied as radial bores.

9. A drive system according to one of the preceding claims, characterised in that the cross-section of the cutouts, with increasing radial distance from the axis of rotation of the pinion cage, increases proportionally to this radial distance.

10. A drive system according to one of the preceding claims, characterised in that an antenna is arranged on the inner side of the housing part or ring gear of the planetary gear unit.

11. A drive system according to one of the preceding claims, characterised in that planet pins (4) are received in the pinion cage, on which planet pins there are rotatably mounted planet wheels which mesh both with the ring gear (1) and with the sun wheel.

12. A drive system according to one of the preceding claims, characterised in that the printed circuit board and / or the emitter module is / are arranged in a plastics-material housing which is arranged and / or inserted in the blind bore.

13. A drive system according to one of the preceding claims, characterised in that the pinion cage is rotatably mounted by means of a first bearing (2) and a second bearing (11), with the inner ring of the first bearing (2) being mounted on the second side piece, with the outer ring of the first bearing (2) being received in the housing part and being adjusted against and against a or the ring gear or against a collar protruding radially inwards and receiving the ring gear, with the inner ring of the second bearing (11) being mounted on the second side piece and being adjusted against a step of the second side piece, with the outer ring of the second bearing (11) being received in the housing part and being adjusted against a or the ring gear or against a collar protruding radially inwards and receiving the ring gear, with a shaft nut (3) screwed onto a threaded region of the second side piece pressing onto the inner ring of the first bearing (2).

14. A drive system according to one of the preceding claims, characterised in that a shaft sealing ring is received in the housing part and seals off towards the first side piece, and / or in that the region covered in the axial direction by the blind bore encompasses the region covered in the axial direction by the radially directed cutouts.

15. A drive system according to one of the preceding claims, characterised in that on the planetary gear unit there is arranged an evaluation unit which is connected to an antenna which is arranged on the inner side of the housing part.