DE102018113350A1 - Drive device with a transmission device for a robot - Google Patents

Abstract

The invention relates to a drive device for a robot, comprising an electric machine (1) which is operatively connected via a drive shaft (2) to a transmission device (3), wherein the transmission device (3) has a first and second planetary stage (4, 5) wherein the first planetary stage (4) comprises a first planetary gear set with a plurality of planetary gears (6), the planet gears (6) of the first planetary gear set consisting of two axially adjacent gear halves (6a, 6b) and one axially between the two gear halves (6a, 6b) arranged annular ring-shaped torsion spring (11) are formed, further wherein the planetary gears (6) of the first planetary set are rotatably mounted on a first planet carrier (8a) and with a first sun gear (9a) and with a first ring gear (10a) meshing, wherein the second planetary stage (5) has a second planetary gearset with a plurality of planetary gears (7), wherein the planetary gears (7) of the second tarpaulin are rotatably mounted on a second planet carrier (8b) and are in meshing engagement with a second sun gear (9b) and with a second ring gear (10b), wherein the drive shaft (2) rotatably with the first and the second sun gear (9a, 9b) is connected, and wherein the first ring gear (10a) rotatably connected to the second planet carrier (8b) is connected.

Description

The invention relates to a drive device with a transmission device for a robot. Furthermore, the invention relates to a robot, in particular a robot arm with such a drive device.

Drive devices for robots require precision gears, which are formed substantially free of play. In other words, a tooth engagement between two gears must be designed such that there is no play between the tooth flanks of the gears.

If gears of a transmission are idle or change from one direction of rotation to another, it may result, inter alia, disturbing noises due to a game between abutting tooth flanks of the gears. Backlash between tooth flanks of gears is undesirable in precision gears, which are for example intended for robotics applications.

The DE 10 2015 206 063 A1 discloses a gear for a gear transmission, which is divided into two axially adjacent spur gears, and having an annular segment-shaped torsion spring, between the circumferentially opposite spring ends a slot is formed, engage in the two each one of the two spur gears associated cam, of which a cam is assigned to one of the two spring ends and the other cam is assigned to the other spring end. For example, the gear is designed as a planetary gear for a planetary gear. The teeth of both spur gears can mesh with a ring gear of the planetary gear. In each case a tooth of both spur gears engages in a common tooth gap of the mating gear, wherein the one tooth of a spur gear on one tooth space delimiting the tooth of the mating gear and the other tooth of the other spur gear on the other tooth gap limiting tooth of the mating gear can rest without play ,

The object of the present invention is to provide a drive device with a transmission device for a robot, wherein the drive device should not only be built substantially free of play and compact, but also should have a high transmission ratio. The object is solved by the subject matter of claim 1. Preferred embodiments are given in the dependent claims.

The inventive drive device for a robot comprises an electric machine, which is operatively connected via a drive shaft with a transmission device, wherein the transmission device comprises a first and second planetary stage, wherein the first planetary stage comprises a first planetary gear set with a plurality of planetary gears, wherein the planetary gears of the first planetary gear set two axially adjacent gear halves and an axially disposed between the two gear halves annular segment-shaped torsion spring are formed, further wherein the planetary gears of the first planetary set are rotatably mounted on a first planet carrier and are in meshing engagement with a first sun gear and a first ring gear, wherein the second planetary stage a having second planetary gear set with a plurality of planetary gears, wherein the planetary gears of the second planetary gear set are rotatably arranged on a second planet carrier and with a second sun gear and are in meshing engagement with a second ring gear, wherein the drive shaft is rotatably connected to the first and the second sun gear, and wherein the first ring gear is rotatably connected to the second planet carrier. Thus, the transmission device is designed as a precision gear and provided due to the compact arrangement of only two planetary gear sets for use in a robot, in particular a robot arm.

The term "operatively connected" is to be understood that two transmission elements may be directly connected to each other, or that there are other transmission elements between two transmission elements, for example, one or more shafts or gears. Two meshing gears are provided for transmitting torque and rotational speed from one gear to the other gear. Under a gear, for example, a sun gear, a ring gear and a planetary gear of a planetary gear set to understand.

Preferably, the first planet carrier is fixed to a housing of the transmission device stationary. Consequently, the planet carrier is rotatably connected to the housing. Preferably, the second ring gear is operatively connected to an output shaft of the transmission device. In particular, the drive shaft is arranged on a common axis with the output shaft. The drive shaft and the output shaft are arranged axially adjacent to each other.

Preferably, the electric machine has a stator and a rotor, wherein the rotor is non-rotatably connected to the drive shaft. Thus, the drive shaft is designed as a rotor shaft.

The invention includes the technical teaching that a first gear ratio in the first planetary stage is not equal to a second gear ratio in the second planetary stage. For example, the first gear ratio is chosen such that a rotational speed of the drive shaft of 1000 revolutions per minute leads to a rotational speed of the first ring gear of 360 revolutions per minute. In addition to this first gear ratio, the second gear ratio, for example, selected such that the speed of the drive shaft of 1000 revolutions per minute and the speed of the first ring gear of 360 revolutions per minute leads to a speed of the output shaft of 40 revolutions per minute. In particular, the first gear ratio is 0.36, wherein the second gear ratio is 0.5.

Preferably, the respective torsion spring has a gap between its circumferentially opposite spring ends, into which two cams each associated with one of the two gear halves engage, of which one cam is assigned to one of the two spring ends and the other cam is assigned to the other spring end. When the two gear halves are rotated against each other, press both cams, the spring ends under an enlargement of the gap elastically apart. Thus, the two gear halves are braced in a tooth engagement with the ring gear and the sun gear in the circumferential direction to avoid a backlash.

Preferably, the two gear halves of the respective planet gear are formed substantially identical, wherein the respective cam is integrally connected to the respective gear half. Further, preferably, the torsion spring has a substantially rectangular cross-sectional profile, which is arranged in a circular arc around an axis of rotation of the respective planetary gear. Thus, the torsion spring is C-shaped.

• 1 eine vereinfachte schematische Darstellung zur Veranschaulichung des Aufbaus einer erfindungsgemäßen Antriebsvorrichtung, und
• 2 eine schematische Querschnittdarstellung zur Veranschaulichung des Aufbaus eines Planetenrades des ersten Planetensatzes.

Further measures improving the invention will be described in more detail below together with the description of a preferred embodiment of the invention with reference to the two figures. Show

• 1 a simplified schematic representation to illustrate the structure of a drive device according to the invention, and
• 2 a schematic cross-sectional view illustrating the structure of a planetary gear of the first planetary gear set.

According to 1 has a drive device according to the invention for a - not shown here - arm of a robot an electric machine 1 and a transmission device 3 on. The electric machine 1 has a stator 13 and a rotor 14 on. A drive power of the electric machine 1 is via a drive shaft 2 between the electric machine 1 and the transmission device 3 arranged and designed as a rotor shaft, in the transmission device 3 initiated.

The transmission device 3 includes a first and second planetary stage 4 . 5 , The first planetary stage 4 has a first planetary gear set with multiple planetary gears 6 on, with the planetary gears 6 of the first planetary gear set of two axially adjacent gear halves 6a . 6b and one axially between the two gear halves 6a . 6b arranged annular segment-shaped torsion spring 11 are formed to allow a backlash-free tooth engagement. Further, the planet gears 6 of the first planetary set rotatably on a first planet carrier 8a arranged and stand with a first sun gear 9a and with a first ring gear 10a in the tooth mesh.

The second planetary stage 5 has a second planetary gear set with multiple planetary gears 7 on, with the planetary gears 7 of the second planetary set rotatably on a second planetary carrier 8b are arranged. The planet wheels 7 of the second planetary gear set are with a second sun gear 9b as well as with a second ring gear 10b in the tooth mesh. Due to the simplified schematic representation is in each case only one planetary gear 6 of the first planetary gear set and a planetary gear 7 of the second planetary gear set.

The drive shaft 2 is non-rotatable with the first and the second sun gear 9a . 9b connected. The first ring gear 10a is non-rotatable with the second planet carrier 8b connected is. The first planet carrier 8a is on a housing 12 the transmission device 3 fixed in place. The second ring gear 10b is with an output shaft 16 the transmission device 3 rotatably connected. The drive shaft 2 is on a common axis 15 with the output shaft 16 arranged.

After 2 are the two gear halves 6a . 6b on a common bearing pin 18 arranged. Each gear half 6a . 6b is via a respective plain bearing bush 19a . 19b rotatable on the bearing pin 18 stored. The bearing bolt 18 is at the first planet carrier 8a added. The torsion spring 11 has a substantially rectangular cross-sectional profile, the circular arc around an axis of rotation of the planetary gear 6 is arranged around. Furthermore, the torsion spring 11 between the circumferentially opposite spring ends a gap, in the two each one of the two gear halves 6a . 6b associated cams 17a . 17b intervene, one of which is a cam 17a one of the two spring ends and the other cam 17b associated with the other spring end. The two gear halves 6a . 6b are formed substantially identical, wherein the respective cam 17a . 17b integral with the respective gear half 6a . 6b connected is. For installation and operation of the two gear halves 6a . 6b reference is made in particular to paragraphs [0059], [0060] and [0061] of the document cited in the introduction to the description DE 10 2015 206 063 A1 referred to the prior art.

LIST OF REFERENCE NUMBERS

1

electric machine

2

drive shaft

3

transmission device

4

first planetary stage

5

second planetary stage

6

planet

6a, 6b

gear half

7

planet

8a, 8b

planet carrier

9a, 9b

sun

10a, 10b

ring gear

11

torsion spring

12

casing

13

stator

14

rotor

15

axis

16

output shaft

17a, 17b

cam

18

bearing bolt

19a, 19b

plain bearing bush

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 102015206063 A1 [0004, 0018]

Claims (10)

A driving apparatus for a robot, comprising an electric machine (1) operatively connected to a transmission device (3) via a drive shaft (2), the transmission device (3) having first and second planetary stages (4, 5), the first one Planet stage (4) has a first planetary gear set with a plurality of planet gears (6), wherein the planet gears (6) of the first planetary gear set of two axially adjacent gear halves (6a, 6b) and an axially between the two gear halves (6a, 6b) arranged annular ring-shaped torsion spring ( 11), wherein furthermore the planetary gears (6) of the first planetary gearset are rotatably arranged on a first planetary carrier (8a) and mesh with a first sun gear (9a) and with a first ring gear (10a), wherein the second planetary gear stage ( 5) has a second planetary gear set with a plurality of planetary gears (7), wherein the planet gears (7) of the second planetary gear set rotatably on a z wide planet carriers (8b) are arranged and with a second sun gear (9b) and with a second ring gear (10b) meshing with the drive shaft (2) rotatably connected to the first and the second sun gear (9a, 9b), and wherein the first ring gear (10a) rotatably connected to the second planetary carrier (8b) is connected. Drive device after Claim 1 , characterized in that the first planetary carrier (8a) on a housing (12) of the transmission device (3) is fixed stationary. Drive device according to one of the preceding claims, characterized in that the second ring gear (10b) with an output shaft (16) of the transmission device (3) is operatively connected. Drive device according to one of the preceding claims, characterized in that the electric machine (1) has a stator (13) and a rotor (14), wherein the rotor (14) is non-rotatably connected to the drive shaft (2). Drive device according to one of the preceding claims, characterized in that a first gear ratio in the first planetary stage (4) is not equal to a second gear ratio in the second planetary stage (5). Drive device after Claim 3 , characterized in that the drive shaft (2) on a common axis (15) with the output shaft (16) is arranged. Drive device according to one of the preceding claims, characterized in that the respective torsion spring (11) between the circumferentially opposite spring ends has a gap, in the two each one of the two gear halves (6a, 6b) associated cam (17a, 17b) engage, of to which one cam (17a) is assigned to one of the two spring ends and the other cam (17b) to the other spring end. Drive device according to one of the preceding claims, characterized in that the two gear halves (6a, 6b) of the respective planetary gear (6) are formed substantially identical, wherein the respective cam (17a, 17b) integral with the respective gear half (6a, 6b) connected is. Drive device according to one of the preceding claims, characterized in that the torsion spring (11) has a substantially rectangular cross-sectional profile, which is arranged in a circular arc about an axis of rotation of the respective planet wheel (6) around. Robot comprising a drive device according to one of the preceding claims.

Images