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Dokumentenidentifikation EP1187704 13.11.2003
EP-Veröffentlichungsnummer 1187704
Titel INDUSTRIEROBOTER
Anmelder ABB AB, Västeras, SE
Erfinder LUNDSTRÖM, Christer, S-745 71 Enköping, SE;
NISSFOLK, Rafael, S-722 40 Väster s, SE
Vertreter derzeit kein Vertreter bestellt
DE-Aktenzeichen 60005824
Vertragsstaaten AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LI, LU, MC, NL, PT, SE
Sprache des Dokument EN
EP-Anmeldetag 20.06.2000
EP-Aktenzeichen 009466095
WO-Anmeldetag 20.06.2000
PCT-Aktenzeichen PCT/SE00/01303
WO-Veröffentlichungsnummer 0001000369
WO-Veröffentlichungsdatum 04.01.2001
EP-Offenlegungsdatum 20.03.2002
EP date of grant 08.10.2003
Veröffentlichungstag im Patentblatt 13.11.2003
IPC-Hauptklasse B25J 9/10

Beschreibung[en]
TECHNICAL FIELD

The present invention relates to a gearbox configuration of an industrial robot.

PRIOR ART

In i. e. industrial robots with six axes, which have a vertically articulated arm mounted on a stand (fig. 2), the driving means of the arm are placed near the centre of rotation of the arm. The remaining three driving means are arranged closer to the working tool of the robot. The aim is inter alia to give the industrial robot a compact construction and to contribute to keeping the weight of the arm low. Accordingly, the three driving means are arranged in the lower part of the robot towards the stand and generally comprise electrical motors. Each motor drives one shaft each for driving of the different degrees of freedom of the robot through gear and transmission. The gear generally comprises a toothed transmission gear enclosed in a gear housing filled with cooling and lubricant medium, which usually consist of oil.

The patent document US 4 671 732 discloses an industrial robot with six axes having three driving means 21, 22 and 23 arranged in the lower part of the robot near the stand. The three driving means are identical, which simplifies the design and possible repair of the robot. The three driving units are completely separated from each other regarding accommodation for lubricant. The robot is designed to tolerate high requirements for accuracy despite wear of the parts included.

In operation the industrial robot is generally part of a production line, which can include e. g. a press. The robot supplies the press with moulding blanks that come to the robot over some type of conveyor.

The technical development aims at faster presses and also faster conveyors. This has entailed that the speed of the robot has had to increase concurrently with the development. The speed of driving and translation has increased approximately fivefold in the last fifteen years. This has led to that the enclosed toothed transmission gears under high bearing pressure must be driven with ever higher velocity, which requires increasing effect supply and gives increasing generation of heat in the gears, which increases the friction heat on the teeth.

For the purpose of absorbing and disposing heat from the teeth a cooling and lubricant medium encloses the gear. Problems arise when the driving and translation speed of the robot and the heat generation are so high that the cooling medium cannot cool the gear. Then, the flanks of the gear run the risk of being damaged from the high temperature. Thus, too high temperatures drastically decrease the lifetime of the gear. The risk of frequent shut downs and expensive repairs of the robot increases.

The three lower driving units in the robot are not driven equally and the corresponding gears are heated unequally. This results in an uneven distribution of the generated heat, which leads to different local thermal expansions in the material / metal of the robot, which in turn leads to deformities in the construction of the robot. The accuracy of the robot is decreased and the robot cannot fulfil the requirements called for by the user of the robot.

Another problem that arises at high temperatures is that the accuracy of the work of the robot is increased. In a robot with six axes the driving unit, which drives the rotational movement of the robot around the vertical axis A (fig. 2) and its gear, is charged the most and must be driven at very high speed. There, the temperature becomes very high and causes temperature differences to occur in different parts of the cooling and lubricant medium in the gearbox of the motor. This entails in turn means that the turn plate around which the robot is constructed and which secures the rotation around axis A is heated unevenly, which has a negative influence on the accuracy.

Traditionally the above problems are solved through arranging cooling flanges on the outside of the gearboxes. Even an external cooler e. g. a cooling fan can help to decrease the temperature. All such solutions are bulky and insufficient and they are not suitable for an industrial robot, which is part of a production line.

Another problem is that three completely separated gearboxes require filling and discharge of cooling and lubricant medium and also aeration in three different places. This takes time, is dirty to handle and leads to unwanted or unnecessarily long shutdowns.

In production of industrial robots the need arises for a robot which can make fast speed with maintained accuracy. Furthermore, it should be easy to give the robot the necessary operation service.

The robot in the cited American patent document cannot fulfil this need.

Further industrial robots, having a common gear housing, are known from EP 0 322 670 A and US 4 586 868 A.

SUMMARY OF THE INVENTION

In producing industrial robots a manipulator is equipped with i.e. control system and also motor driven gears and optional appurtenant transmissions. The development of robots has the aim of creating a faster robot, which corresponds to the possibilities of the surrounding equipment and the requirements of the customer. The aim is also to simplify and shorten the time for operative service of the robot.

Accordingly, the object of the present invention is to achieve an industrial robot including at least two motor driven gears, where the gears are arranged so that the requirement of sufficient cooling is fulfilled at the same time as the robot reaches provided requirements of accuracy and the time for service decreases.

This object is solved by the features of claims 1(apparatus) and 4 (method).

A gear box requires an opening for filling and a separate opening for discharging cooling and lubricant medium and also magnetic stoppers to keep the medium, e. g. the oil, free from wear particles. During operation an overpressure occurs in the gear unit e. g. because of heat expansion of the cooling and lubricant medium and therefore the gearbox often is provided with a type of breathing stopper.

It is also included in the scope of invention to design the gear housing with only one opening for common filling of lubricant oil and moreover only one discharge place for the oil. Aeration also can occur jointly through one or several aerating openings.

DESCRIPTION OF THE DRAWING

The invention will be explained in greater detail by describing an example of an embodiment with reference to the enclosed drawing, where:

  • Fig. 1 shows a gearbox configuration arranged in an industrial robot in accordance with the present invention,
  • Fig. 2 shows an industrial robot with six axes arranged with three driving units in the lower part of the robot.

DESCRIPTION OF EMBODIMENTS

In an industrial robot comprising a manipulator with a control system (fig. 2) electrically driven gears are arranged in the lower part of the robot at the stand to give the movements of the robot arm. Each electrical motor transmits rotational movements to a toothed transmission gear, which usually drives a transmission that transmits movements to the robot arm. In fig. 2, a six axes industrial robot 1 with a stand 2 is shown, and also the thereon rotationally mounted robot foot 3. A first driving unit 4 (fig. 1) is arranged to rotate the robot around the vertical axis A through a first toothed transmission gear 5. A second driving unit 6 is arranged to rotate the robot arm around a horizontal axis B through a second toothed gear transmission 7. A third driving unit 8 is arranged to rotate the robot arm around the horizontal axis C through a third toothed transmission gear 9. The first 5, second 7 and third gear 9 are arranged in a common gear housing 10. The gear housing 10 is cast in one piece, and because of technical reasons of design and strength the housing is subdivided into several inner compartments 10a, 10b and 10c, which are connected with passage channels. The gear housing 10 is filled with cooling and lubricant medium 12, which surrounds the gears 5, 7 and 9.

During operation of the robot the first, second and third motor and their gears are working in different degrees to make the robot perform the desired movements.

Through driving of the different gears, the surrounding cooling and lubricant medium 12 is caused to circulate. The cooling and lubricant medium absorbs heat from the teeth and through the circulation in the common gear housing and any temperature differences in the medium 12 are levelled out, and a uniform temperature is obtained in the whole housing.

ALTERNATIVE EMBODIMENTS

To facilitate / speed up the circulation of the agent 12, an external device 13 can be connected to the gear housing viz. a pump (not shown).


Anspruch[de]
  1. Industrieroboter (1), der einen Manipulator mit einem Steuersystem umfasst, wobei die Bewegungen des Manipulators von wenigstens zwei motorbetriebenen Getrieben angetrieben werden, wobei die Getriebe in einem gemeinsamen Getriebegehäuse (10) angeordnet sind, dadurch gekennzeichnet, dass das Getriebegehäuse ein in dem Getriebegehäuse zirkulierendes gemeinsames Kühl- und Schmiermedium (12) enthält.
  2. Industrieroboter gemäß Anspruch 1, dadurch gekennzeichnet, dass eine externe Vorrichtung (13) die Zirkulation des Kühl- und Schmiermediums (12) erleichtert/beschleunigt.
  3. Industrieroboter gemäß Anspruch 2, dadurch gekennzeichnet, dass die externe Vorrichtung (13) eine Pumpe ist.
  4. Verfahren zur Kühlung und Schmierung eines Industrieroboters (1), der einen Manipulator, der mit einem Steuersystem bereitgestellt ist, und wenigstens zwei motorbetriebene Getriebe umfasst, wobei die Getriebe in einem gemeinsamen Getriebegehäuse (10) angeordnet sind, dadurch gekennzeichnet, dass die Getriebe durch die Zirkulation eines gemeinsamen Kühlund Schmiermediums (12) in dem für die Getriebe gemeinsamen Getriebegehäuse gekühlt und geschmiert werden.
  5. Verfahren gemäß Anspruch 4, dadurch gekennzeichnet, dass die Zirkulation des Kühl- und Schmiermediums (12) zur Zirkulation mittels einer Pumpe veranlasst wird.
Anspruch[en]
  1. Industrial robot (1) including a manipulator with control system, where the movements of the manipulator are driven by at least two motor driven gears wherein the gears are arranged in a common gear housing (10) characterised in that said gear housing contains an in the gear housing circulating common cooling and lubricant medium (12).
  2. Industrial robot according to claim 1, characterised in that an external device (13) facilitates / speeds up the circulation of the cooling and lubricant medium (12).
  3. Industrial robot according to claim 2, characterised in that the external device (13) is a pump.
  4. Method for cooling and lubricating an industrial robot (1) including a manipulator provided with control system and at least two motor driven gears, wherein the gears are arranged in a common gear housing (10) characterised in that said gears are cooled and lubricated by the circulation of a common cooling and lubricant medium (12) in the for the gears common gear housing (10).
  5. Method according to claim 4 characterised in that the circulation of the cooling and lubricant medium (12) is caused to circulate by means of a pump.
Anspruch[fr]
  1. Robot (1) industriel comportant un manipulateur ayant un système de commande, les mouvements du manipulateur étant entraînés par au moins deux engrenages entraînés par moteur, dans lequel les engrenages sont agencés dans un boîtier (10) commun d'engrenages, caractérisé en ce que le boîtier d'engrenages contient un agent (12) de lubrification et de refroidissement commun circulant dans le boîtier d'engrenages.
  2. Robot industriel suivant la revendication 1, caractérisé en ce qu'un dispositif (13) externe facilite/accélère la circulation de l'agent (12) de lubrification et de refroidissement.
  3. Robot industriel suivant la revendication 2, caractérisé en ce que le dispositif (13) externe est une pompe.
  4. Procédé pour refroidir et lubrifier un robot (1) industriel comportant un manipulateur muni d'un système de commande et d'au moins deux engrenages entraînés par moteur, dans lequel les engrenages sont disposés dans un boîtier (10) commun d'engrenages, caractérisé en ce que les engrenages sont refroidis et lubrifiés par la circulation d'un agent (12) de lubrification et de refroidissement commun dans le boîtier (10) d'engrenages commun aux engrenages.
  5. Procédé suivant la revendication 4, caractérisé en ce que la circulation de l'agent (12) de lubrification et de refroidissement est amené à circuler au moyen d'une pompe.






IPC
A Täglicher Lebensbedarf
B Arbeitsverfahren; Transportieren
C Chemie; Hüttenwesen
D Textilien; Papier
E Bauwesen; Erdbohren; Bergbau
F Maschinenbau; Beleuchtung; Heizung; Waffen; Sprengen
G Physik
H Elektrotechnik

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