WO2019196068A1

WO2019196068A1 - Robot of scara type and method for manufacturing the robot

Info

Publication number: WO2019196068A1
Application number: PCT/CN2018/082877
Authority: WO
Inventors: Luoluo Wang; Xiaodong Cao; Zhu Zhu; Yuhong Gong
Original assignee: Abb Schweiz Ag
Priority date: 2018-04-12
Filing date: 2018-04-12
Publication date: 2019-10-17

Abstract

Embodiments of the present disclosure relates to a robot of SCARA type. The robot comprises a base; a first arm coupled to the base, the first arm being rotatable about a first axis relative to the base when driven by a first motor arranged in the base via a first transmission mechanism; and a second arm coupled to the first arm, the second arm being rotatable about a second axis relative to the first arm when driven by a second motor via a second transmission mechanism, the second axis being substantially parallel to the first axis, and the first and/or second transmission mechanism comprising a multi-stage gear transmission mechanism at least including a first gear stage and a second gear stage connected in parallel to the first gear stage. By use of the multi-stage transmission mechanism, it is possible to improve the stiffness of the transmission mechanism and achieve high transmission efficiency.

Description

ROBOT OF SCARA TYPE AND METHOD FOR MANUFACTURING THE ROBOT

TECHNICAL FIELD

Embodiments of present disclosure generally relate to the field of industrial robots, and more particularly, to a robot of selective compliance assembly robot arm (SCARA) type and a method for manufacturing the robot.

BACKGROUND

Robots of SCARA type, also referred to as SCARA robots, are widely used in industrial applications including Electronics Manufacturing Services (EMS) to improve productivity, reduce costs and improve quality and can be used, for example, in welding, painting, removal of goods, or the like. A conventional SCARA robot typically includes a base, a rear arm, and a forearm. The base is usually mounted on a floor or a work table. The rear arm is connected to the base and rotatable about an axis ( “axis A” ) relative to the base when driven by a motor ( “motor A” ) . The forearm is connected to the rear arm and rotatable about an axis ( “axis B” ) parallel to the axis A relative to the rear arm when driven by a motor ( “motor B” ) .

Traditionally, the motor A is mounted in the base and drives the rear arm by driving a reducer connected to the rear arm and the motor B is mounted in the forearm and drives the forearm by driving a reducer connected to the rear arm. The two reducers are generally designed as harmonic reducers which use non-rigid, thin cylindrical cups with small external teeth as their splines. The work principle of the harmonic reducer is based on its elastic deformation. However, due to the small teeth and elastic deformation of the reducer elements, the stiffness of the transmission mechanism is greatly limited, which reduces the speed and productivity of the SCARA robot.

SUMMARY

Example embodiments of the present disclosure propose a robot of SCARA type and a method for manufacturing the robot.

In an aspect of the present disclosure, a robot of SCARA type is provided. The robot comprises a base; a first arm coupled to the base, the first arm being rotatable about a first axis relative to the base when driven by a first motor arranged in the base via a first transmission mechanism; and a second arm coupled to the first arm, the second arm being rotatable about a second axis relative to the first arm when driven by a second motor via a second transmission mechanism, wherein the second axis is substantially parallel to the first axis, and wherein at least one of the first and second transmission mechanisms comprises a multi-stage gear transmission mechanism, the multi-stage gear transmission mechanism at least including a first gear stage and a second gear stage connected in parallel to the first gear stage.

In some example embodiments, the second motor is arranged in the first arm.

In some example embodiments, the second transmission mechanism comprises the multi-stage gear transmission mechanism and further comprises: a first timing belt connected between the second motor and the first gear stage.

In some example embodiments, the second motor is arranged in the base, and wherein the second transmission mechanism is arranged in the first arm.

In some example embodiments, the second transmission mechanism comprises the multi-stage gear transmission mechanism and further comprises: a second timing belt connected to the first gear stage and arranged in the first arm; and a third timing belt connected to the second motor and arranged in the base. The second and third timing belts are arranged such that the second arm is rotatable about the second axis relative to the first arm when driven by the second motor.

In some example embodiments, the second and third timing belts are arranged with respect to the first axis.

In some example embodiments, the second transmission mechanism comprises the multi-stage gear transmission mechanism and further comprises: a fourth timing belt connected to the second motor and arranged in the base, wherein the fourth timing belt and the first gear stage are arranged with respect to the first axis.

In some example embodiments, at least one of the first and second gear stages includes a first gear wheel and a second gear wheel meshing with the first gear wheel.

In some example embodiments, the second gear stage has wedge-like teeth in the direction of its axis of rotation.

In some example embodiments, the second gear stage is arranged to a shaft and the shaft is connected to a housing of the base or the first arm via a spring.

In some example embodiments, the robot further comprises an operating unit arranged in the second arm and including a first shaft, the first shaft being rotatable about a third axis relative to the second arm when driven by a third motor arranged in the second arm via a third transmission mechanism, wherein the third axis is substantially parallel to the first and second axes.

In some example embodiments, the operating unit further includes a second shaft connected to the first shaft via a connecting part, the second shaft being rotatable when driven by a fourth motor arranged in the second arm via a fourth transmission mechanism. The first shaft is movable along the third axis relative to the second arm when driven by the fourth motor.

In another aspect of the present disclosure, a method is provided for manufacturing the robot of SCARA type according to any of the previous embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Through the following detailed descriptions with reference to the accompanying drawings, the above and other objectives, features and advantages of the example embodiments disclosed herein will become more comprehensible. In the drawings, several example embodiments disclosed herein will be illustrated in an example and in a non-limiting manner, wherein:

Fig. 1 illustrates a schematic diagram of a conventional SCARA robot;

Fig. 2 illustrates a schematic diagram of a harmonic reducer used in the conventional SCARA robot of Fig. 1;

Fig. 3 illustrates a schematic diagram of a SCARA robot in accordance with some example embodiments of the present disclosure;

Fig. 4 illustrates a schematic diagram of a SCARA robot in accordance with some other example embodiments of the present disclosure; and

Fig. 5 illustrates a schematic diagram of a SCARA robot in accordance with some other example embodiments of the present disclosure.

Throughout the drawings, the same or corresponding reference symbols refer to the same or corresponding parts.

DETAILED DESCRIPTION

Principles of the present disclosure will now be described with reference to several example embodiments shown in the drawings. Though example embodiments of the present disclosure are illustrated in the drawings, it is to be understood that the embodiments are described only to facilitate those skilled in the art in better understanding and thereby achieving the present disclosure, rather than to limit the scope of the disclosure in any manner.

The term “comprises” or “includes” and its variants are to be read as open terms that mean “includes, but is not limited to. ” The term “or” is to be read as “and/or” unless the context clearly indicates otherwise. The term “based on” is to be read as “based at least in part on. ” The term “being operable to” is to mean a function, an action, a motion or a state can be achieved by an operation induced by a user or an external mechanism. The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ”

Unless specified or limited otherwise, the terms “mounted, ” “connected, ” “supported, ” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Furthermore, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. In the description below, like reference numerals and labels are used to describe the same, similar or corresponding parts in the Figures. Other definitions, explicit and implicit, may be included below.

As discussed above, the use of the harmonic reducers in a conventional SCARA robot will limit the stiffness of the transmission mechanism and thus reduces the speed and productivity of the SCARA robot. Fig. 1 illustrates a schematic diagram of a conventional SCARA robot 100. As shown, the robot 100 includes a base 110, a rear arm 120, a forearm 130 and an operating unit 140. The base 110 may be mounted on a floor or a working table (not shown) . The rear arm 120 is coupled to the base 110 and rotatable about a first axis X1 relative to the base 110. The forearm 130 is coupled to the rear arm 120 and rotatable about a second axis X2 relative to the rear arm 130. The second axis X2 is substantially parallel to the first axis X1. In some cases, there may be a dresspack 150 between the base 110 and the forearm 130 in the robot 100, which protects the cables and tubes inside. In addition, a cover 160 is included to cover the forearm 130 to protect the components inside.

In operation, a motor 112 arranged in the base 110 can be used to drive a reducer 122 connected to the rear arm 120 (arranged in the rear arm 120 in this example) such that the rear arm can rotate about the first axis X1. A motor 131 can drive a reducer 124 connected to the rear arm 120 (arranged in the rear arm 120 in this example) such that the forearm 130 can rotate about the second axis X2. The motor 131 is arranged in the forearm 130. The

reducers

122 and 124 may be considered as transmission mechanisms for the

motors

112 and 131, respectively.

The operating unit 140 is arranged in the forearm 130 and includes a first shaft 162, a second shaft 164, and a connecting part 166 connected therebetween. The first shaft 162 may be a spline shaft and is rotatable about a third axis X3 relative to the forearm 130 when driven by a third motor 132 via timing

belts

133 and 134. The third axis X3 is substantially parallel to the first and second axes X1, X2. The first shaft 162 may also be movable along the third axis X3 relative to the forearm 130 when driven by a fourth motor 135. Specifically, the fourth motor 135 drives the second shaft 164 to rotate and then drive the connecting part 166 and the first shaft 162 to slide along the third axis X3 via a timing belt 136. The rotation of the second shaft 164 may cause the first shaft 162 to slide along the third axis X3. The third and

fourth motors

132 and 135 are both included in the forearm 130.

In the conventional robot 100, the

reducers

122 and 124 are designed as harmonic reducers. Fig. 2 shows a schematic diagram of a harmonic reducer 200 that can be used as the

reducer

122 or 124 in the conventional robot 100 of Fig. 1. As shown, the harmonic reducer 200 mainly includes three parts, a circular spline 210, a flexspline 220, and a wave generator 230. The flexspline 220 is typically a non-rigid, thin cylindrical cup with small external teeth. The work principle of the harmonic reducer is based on its elastic deformation. However, due to the small teeth and elastic deformation of the reducer elements, the stiffness of the transmission mechanism is greatly limited, which reduces the speed and productivity of the SCARA robot.

According to example embodiments of the present disclosure, instead of using the harmonic reducers, a multi-stage gear transmission mechanism is employed in a robot of SCARA type to provide the transmission for the rotation of one or more arms (the rear arm and/or the forearm) in the robot. The multi-stage gear transmission mechanism used in the embodiments of the present disclosure includes at least first and second gear stages. The cylindrical gears usually have bigger and harden teeth and may provide higher transmission efficiency than the harmonic reducer, which means lower friction and lower dissipated heat for the robot.

Example embodiments of the present disclosure will be described below with reference to the drawings.

Fig. 3 illustrates a schematic diagram of a robot of SCARA type in accordance with some example embodiments of the present disclosure. Figs. 4-5 illustrate some alternative structures of the robot of SCARA type in accordance with some other embodiments of the present disclosure.

Reference is first made to Fig. 3, which illustrates a robot of SCARA type 300 in accordance with some example embodiments of the present disclosure. As shown, the robot 300 includes a base 310, a first arm 320, and a second arm 330. The base 310 may be mounted on a floor or a working table (not shown) . The first arm 320 is coupled to the base 310 and is rotatable about a first axis X1 relative to the base 310. The second arm 330 is coupled to the first arm 320 and is rotatable about a second axis X2 relative to the first arm 320. The second axis X2 is substantially parallel to the first axis X1. The first arm 320 may be referred to as a rear arm or a lower arm while the second arm 330 may be referred to as a forearm or an upper arm in some cases.

The first arm 320 is rotatable about the first axis X1 relative to the base 310 when driven by a first motor 312 via a first transmission mechanism 301. The first motor 312 is arranged in the base 310. The first transmission mechanism 301 is arranged in the base 310 together with the first motor 312 and is used to reduce the output speed of the first motor 312. The first transmission mechanism 301 is a multi-stage gear transmission mechanism including a first gear stage 314 and a second gear stage 316 connected in parallel to the first gear stage 314. It would be appreciated that although the second gear stage 316 is shown to be arranged above the first gear stage 314, the second gear stage 316 may also be arranged below the first gear stage 314 in other implementations. In some embodiments, one of the first and second gear stages 314, 316 are arranged to cover at least part of the other one. The arrangement of the multi-stage gear transmission mechanism will be described in detail below.

The second arm 330 is rotatable about the second axis X2 relative to the first arm 320 when driven by a second motor 322 via a second transmission mechanism 302. In the example of Fig. 3, the second motor 322 is arranged in the first arm 320. The second transmission mechanism 302 is arranged in the first arm 320 together with the second motor 322 and is used to reduce the output speed of the second motor 322. The second transmission mechanism 302 is a multi-stage gear transmission mechanism including a first gear stage 324 and a second gear stage 326 connected in parallel to the first gear stage 324. It would be appreciated that although the second gear stage 326 is shown to be arranged above the first gear stage 324, the second gear stage 326 may also be arranged below the first gear stage 324 in other implementations. In some embodiments, one of the first and second gear stages 324, 326 are arranged to cover at least part of the other one.

To better understand the multi-stage gear transmission mechanism, Fig. 3 also illustrates details of the first transmission mechanism 301. As shown, the first gear stage 314 includes a first gear wheel 371 arranged on an output shaft 380 of the first motor 312 and a second larger gear wheel 372 meshing (or engaging) with the first gear wheel 371. As such the first gear stage 314 can reduce the speed of the output shaft 380 of the first motor 312. The second gear stage 316 includes a first gear wheel 373 arranged on a shaft 370 and a second larger gear wheel 374 meshing (or engaging) with the first gear wheel 373. The

gear wheels

371 and 374 have cylindrical and rigid gears. The shaft 370 is coupled to the gear wheel 372 of the first gear stage 314 and is arranged to be rotatable about an axis parallel to the output shaft 380 of the first motor 312. As such the second gear stage 316 can further reduce the speed of the output shaft 380 of the first motor 312. In some example embodiments, the shaft 370 may be connected to a housing of the base 310 via a spring 375.

In some example embodiments, the second gear stage 316 may have wedge-like teeth in the direction of its axis of rotation. For example, both the

gear wheels

373 and 374 have the wedge-like teeth as shown in Fig. 3. Since the shaft 370 is influenced by way of the spring 375 in the direction of its longitudinal extent, the wedge-like teeth will all the time be pressed to intimately mesh with each other to eliminate any play in this last gear stage.

Although only the detailed structure of the first transmission mechanism 301 is illustrated in Fig. 3, the second transmission mechanism 302, if designed as a multi-stage gear transmission mechanism, may also be implemented in a similar manner as the first transmission mechanism 302 to reduce the output speed of the second motor 322. In some example embodiments, the shaft on which a gear wheel of the gear stage is arranged may be connected to a housing of the first arm 320 via a spring.

In some example embodiments, for the convenient arrangement of the second motor 322 and the second transmission mechanism 302 in the first arm 320, the second transmission mechanism 302 further includes a timing belt 328 connected between the second motor 322 and the first gear stage 324 of the second transmission mechanism 302. For example, the timing belt 328 is connected to an output shaft of the second motor 322 at one end and is connected to a gear wheel of the first gear stage 324 at the other end. In this way, the second motor 322 can drive the second arm 330 via the timing belt 328, the first gear stage 324, and the second gear stage 326. By means of the timing belt, it is possible to reduce the dimension of the first arm 320 in a vertical direction.

In some example embodiments, the second transmission mechanism 302 may include more than one timing belt connected in series between the second motor 322 and the first gear stage 324 of the second transmission mechanism 302. In some other embodiments, depending on actual requirements, the first motor 312 may also be connected to the first transmission mechanism 301 and specifically, to the first gear stage 314 via one or more timing belts (not shown) .

It would be appreciated that although the multi-stage gear transmission mechanisms are used for both the first and

second transmission mechanisms

301 and 302, in some other embodiments, one of the first and

second transmission mechanisms

301 and 302 may be designed as another type of transmission mechanism, such as a reducer as used typically used in the SCARA robots. Although the first and

second transmission mechanisms

301 and 302 are illustrated as two-stage gear transmission mechanisms in Fig. 1, in some other embodiments, the first transmission mechanism 301 and/or the second transmission mechanism 302 may also include more than two stages (for example, three or more) depending on actual requirements on the output force and the rotation range.

In embodiments of the robot 300 shown in Fig. 3, the robot 300 further includes an operating unit 340 arranged in the second arm 330. The operating unit 340 may include a first shaft 362, a second shaft 364, and a connecting part 366 connected therebetween. The first shaft 362 may be a spline shaft (for example, a ball spline shaft) and is rotatable about a third axis X3 relative to the second arm 330. A third motor 331 arranged in the second arm 330 may be used to drive the first shaft 362 via a third transmission mechanism consisting of timing

belts

332 and 336. The third axis X3 is substantially parallel to the first and second axes X1, X2. The first shaft 362 may also be movable along the third axis X3 relative to the second arm 330 when driven by a fourth motor 333. Specifically, the fourth motor 333 drives the second shaft 364 to rotate and then drive the connecting part 366 and the first shaft 362 to slide along the third axis X3 via a fourth transmission mechanism consisting of a timing belt 334. The rotation of the second shaft 364 may cause the first shaft 362 to slide along the third axis X3. The second shaft 364 may be a screw shaft (for example, a ball screw shaft) . The third and

fourth motors

331 and 333 are both included in the second arm 330.

It would be appreciated that although an example of the operating unit 340 is illustrated and described above, any other arrangements of operating unit can be included in the second arm 330. In some cases, there may be a dresspack 350 between the base 330 and the second arm 330 in the robot 300, which protects the cables and tubes inside. In addition, a cover 360 is included to cover the second arm 330 to protect the components inside.

In the example embodiments of the present disclosure, by introducing the multi-stage transmission mechanism in the SCARA robot, bigger and hardened teeth of the cylindrical gears included in the multi-stage transmission mechanism can improve the stiffness of the transmission mechanism. In addition, the cylindrical gears usually have higher transmission efficiency than the harmonic reducer, which means lower friction for the robot. Further, as compared with the conventional SCARA robots which usually has the motor for driving the forearm arranged in the forearm together with other motors, such motor for driving the forearm can be arranged in the rear arm, which make the SCARA robot has more reasonable mass distribution, and thus will reduce the load of the first and second axes and requires less power to drive the moveable rear arm and forearm or increase the dynamic performance and robot speed. By arranging the motor for driving the forearm in the rear arm will also help reduce the distance between this motor to the base or the mounting floor, which will improve the heat transfer from the motor to the floor and thus enable continuous operation of the SCARA robot.

Fig. 4 illustrates a different arrangement of the second motor 322 in the robot 300 in accordance to some other embodiments of the present disclosure. In the embodiments of Fig. 4, instead of being arranged in the first arm 320, the second motor 322 is arranged in the base 310 together with the first motor 312. As such, it is possible to reduce the length of the first arm 320. Thus, the robot 300 is very compact in its design and then suitable for use in narrow spaces.

Specifically, as shown in Fig. 4, in addition to the multi-stage gear transmission mechanism, the second transmission mechanism 302 further includes a second timing belt 412 connected to the first gear stage 324 and a third timing belt 414 connected to the second motor 322. The second timing belt 412 is arranged in the first arm 320 and the third timing belt 414 is arranged in the base 310 together with the second motor 322.

The second and

third timing belts

412, 414 are arranged such that the second arm 330 can rotate about the second axis relative to the first arm 320 when driven by the second motor 322. In some example embodiments, the timing

belts

412, 414 are arranged with respect to the first axis X1. In a specific example, the timing belt 412 is connected to a gear wheel of the first gear stage 324 at one end and connected to a shaft (not shown) coaxially with the first axis X1 at the other end. The timing belt 414 is connected to an output shaft of the second motor 322 at one end and is connected to the shaft coaxially with the first axis X1 at the other end. In this way, the second motor 322 can drive the second arm 330 via the timing belt 414, the timing belt 412, the first gear stage 324, and the second gear stage 326.

Although two

timing belts

412 and 414 are shown in Fig. 4, in some example embodiments, the first gear stage 324 may be connected to more than one timing belt and/or the second motor 322 may be connected to more than one timing belt. The timing belts may all be included in the second transmission mechanism 302 for purpose of reducing the output speed of the second motor 322 and achieving the driving of the second arm 330.

In the embodiments of Fig. 4, similar components of the robot 300 as those in Fig. 3 are arranged and operate as in the embodiments described with reference to Fig. 3 and the related description is omitted here for purpose of brevity.

Fig. 5 illustrates another different arrangement of the second motor 322 in the robot 300 in accordance to some other embodiments of the present disclosure. In the embodiments of Fig. 5, in order to further reduce the length of the first arm 320, the timing belt connected to the first gear 324 and arranged in the first arm 320 may be omitted. As shown, in addition to the multi-stage gear transmission mechanism, the second transmission mechanism 302 further includes a fourth timing belt 512 connected to the second motor 322 and arranged in the base 310. As compared with the second transmission mechanism 302 in Fig. 4, the timing belt in the first arm 320 is not needed here.

The timing belt 512 and the multi-stage gear transmission mechanism 302 are arranged such that the second arm 330 can rotate about the second axis relative to the first arm 320 when driven by the second motor 322. The arrangement of the timing belt 512 is similar to that of the timing belt 414 in the embodiments of Fig. 4 except that the timing belt 512 is arranged relative to the first gear stage. In some example embodiments, the timing belt 512 and the multi-stage gear transmission mechanism 302 (specifically, the first gear stage 324) are arranged with respect to the first axis X1. In a specific example, the timing belt 512 is connected output shaft of the second motor 322 at one end and is connected to a shaft (not shown) coaxially with the first axis X1 at the other end. A gear wheel of the first gear stage 324 is connected to the shaft coaxially with the first axis X1. In this way, the second motor 322 can drive the second arm 330 via the timing belt 512, the first gear stage 324, and the second gear stage 326.

Although one timing belt 512 shown in Fig. 5, in some example embodiments, more than one timing belt may be connected in series to the second motor 322 and arranged in the base 310 instead of being provided in the first arm 320. The timing belts may all be included in the second transmission mechanism 302 for purpose of reducing the output speed of the second motor 322 and achieving the driving of the second arm 330.

In the embodiments of Fig. 5, similar components of the robot 300 as those in Fig. 3 are arranged and operate as in the embodiments described with reference to Fig. 3 and the related description is omitted here for purpose of brevity.

Embodiments of the present disclosure also relate to a method for manufacturing the robot of SCARA type as described with reference to any of Figs. 3-5.

It should be appreciated that the above detailed embodiments of the present disclosure are only to exemplify or explain principles of the present disclosure and not to limit the present disclosure. Therefore, any modifications, equivalent alternatives and improvement, etc. without departing from the spirit and scope of the present disclosure shall be included in the scope of protection of the present disclosure. Meanwhile, appended claims of the present disclosure aim to cover all the variations and modifications falling under the scope and boundary of the claims or equivalents of the scope and boundary.

Claims

A robot (300) of selective compliance assembly robot arm (SCARA) type, comprising:

a base (310) ;

a first arm (320) coupled to the base (310) , the first arm (320) being rotatable about a first axis (X1) relative to the base (310) when driven by a first motor (312) arranged in the base (310) via a first transmission mechanism (301) ; and

a second arm (330) coupled to the first arm (320) , the second arm (330) being rotatable about a second axis (X2) relative to the first arm (320) when driven by a second motor (322) via a second transmission mechanism (302) , the second axis (X2) being substantially parallel to the first axis (X1) ;

wherein at least one of the first and second transmission mechanisms (301, 302) comprises a multi-stage gear transmission mechanism, the multi-stage gear transmission mechanism at least including a first gear stage (314; 324) and a second gear stage (316; 326) connected in parallel to the first gear stage (314; 324) .
The robot (300) according to claim 1, wherein the second motor (322) is arranged in the first arm (320) .
The robot (300) according to claim 2, wherein the second transmission mechanism (302) comprises the multi-stage gear transmission mechanism and further comprises:

a first timing belt (328) connected between the second motor (322) and the first gear stage (324) .
The robot (300) according to claim 1, wherein the second motor (322) is arranged in the base (310) , and wherein the second transmission mechanism (302) is arranged in the first arm (320) .
The robot (300) according to claim 4, wherein the second transmission mechanism (302) comprises the multi-stage gear transmission mechanism and further comprises:

a second timing belt (412) connected to the first gear stage (324) and arranged in the first arm (320) ; and

a third timing belt (414) connected to the second motor (322) and arranged in the base (310) ;

wherein the second and third timing belts (412, 414) are arranged such that the second arm (330) is rotatable about the second axis (X2) relative to the first arm (320) when driven by the second motor (322) .
The robot (300) according to claim 5, wherein the second and third timing belts (412, 414) are arranged with respect to the first axis (X1) .
The robot (300) according to claim 4, wherein the second transmission mechanism (302) comprises the multi-stage gear transmission mechanism and further comprises:

a fourth timing belt (512) connected to the second motor (322) and arranged in the base (310) , wherein the fourth timing belt (512) and the first gear stage (324) are arranged with respect to the first axis (X1) .
The robot (300) according to claim 1, wherein at least one of the first and second gear stages (314; 316) includes a first gear wheel (371; 373) and a second gear wheel (372; 374) meshing with the first gear wheel (371; 373) .
The robot (300) according to claim 1, wherein the second gear stage (316; 326) has wedge-like teeth (371, 372) in the direction of its axis of rotation.
The robot (300) according to claim 1, wherein the second gear stage (316; 326) is arranged to a shaft (370) and the shaft (370) is connected to a housing of the base (310) or the first arm (320) via a spring (375) .
The robot (300) according to claim 1, further comprising:

an operating unit (340) arranged in the second arm (330) and including a first shaft (362) , the first shaft (362) being rotatable about a third axis (X3) relative to the second arm (330) when driven by a third motor (331) arranged in the second arm (330) via a third transmission mechanism (332, 336) , wherein the third axis (X3) is substantially parallel to the first and second axes (X1, X2) .
The robot (300) according to claim 11, wherein the operating unit (104) further includes a second shaft (364) connected to the first shaft (362) via a connecting part (366) , the second shaft (364) being rotatable when driven by a fourth motor (333) arranged in the second arm (330) via a fourth transmission mechanism (334) , wherein the first shaft is movable along the third axis (X3) relative to the second arm (330) when driven by the fourth motor (333) .
A method for manufacturing the robot (300) of selective compliance assembly robot arm (SCARA) type according to any of claims 1-12.