CN212312032U - Three-axis and four-axis joint structure of SCARA robot and SCARA robot - Google Patents

Abstract

The utility model relates to a three, four-axis joint structure of SCARA robot, include: the second mechanical arm, the ball spline shaft, the third shaft driving unit and the fourth shaft driving unit. The ball spline shaft is positioned at the execution end; the third shaft driving unit includes: a base and a direct drive motor; the direct drive motor includes: the motor comprises a nut, a motor shaft, a rotor, a stator and a first bearing; the fourth shaft driving unit includes: servo motor, driving pulley, spline female, driven pulley, hold-in range, and second bearing. The utility model also provides a SCARA robot. The utility model discloses in, under the prerequisite that keeps whole compactedness, reduce the degree of difficulty of installation and maintenance, guarantee the small and exquisite of robot, compression cost with guarantee heat-sinking capability. Under the condition of small arm extension, the requirement of motor space layout of the mechanical arm with three or four shafts is met, and the transmission precision and the transmission efficiency of the third shaft joint are improved.

Description

Three-axis and four-axis joint structure of SCARA robot and SCARA robot

Technical Field

The utility model relates to a robot design technical field especially relates to a three of SCARA robot, four-axis joint structure to and a SCARA robot.

Background

A SCARA (Selective compliance Assembly Arm) robot is a special type of industrial robot of the cylindrical coordinate type. The SCARA robot has four axes and four degrees of freedom of motion, including: translation in the direction X, Y, Z and rotational freedom about the Z-axis. The third axis of the SCARA robot is a joint structure that enables translation in the Z-direction, commonly referred to as the Z-axis. While the fourth axis of the SCARA robot is a joint structure that achieves rotational motion about the Z-axis, commonly referred to as the R-axis.

At present, the three-axis and four-axis transmission modes of the SCARA robot in the market mainly adopt synchronous belt transmission, the motors of the three-axis and the four-axis are required to be installed on the same mechanical arm on the side edges, and a speed reducer and a brake are further arranged, so that the structure of the SCARA robot with the small arm spread is very compact, the space of compression equipment is facilitated, and the miniaturization effect is achieved. The defects of the prior synchronous belt transmission mode are as follows:

1. a compact arrangement, leading to difficulties in installation and maintenance;

2. under the condition of setting a small arm extension, the mechanical arm with three shafts and four shafts has the possibility of insufficient space, and two motors cannot be arranged in the limited space, because the length of the pitch line of the synchronous belt is international standard, the synchronous belt can lack the proper length of the pitch line while the motors with three shafts and four shafts are compactly arranged, and the nonstandard synchronous belt is not beneficial to later replacement and maintenance;

3. the transmission mode of the synchronous belt belongs to a non-direct-drive mode, and the transmission precision and the transmission efficiency can be reduced;

4. for the SCARA robot of forearm exhibition, in order to guarantee the small and exquisite of robot, need miniaturize motor, speed reducer and stopper more, the cost improves to the heat dissipation is difficult.

SUMMERY OF THE UTILITY MODEL

Based on this, the utility model provides a three of SCARA robot, four-axis joint structure, with third shaft drive unit and fourth shaft drive unit dislocation overall arrangement on the second arm, and third shaft drive unit adopts the direct drive formula structure setting with the female combination of spline, under the prerequisite that keeps whole compactedness, pull open the installation distance between third shaft drive unit and the fourth shaft drive unit, reduce the degree of difficulty of installation and maintenance, and under the condition that need not to carry out the miniaturization improvement to each part, guarantee small and exquisite of robot, compression cost and assurance heat-sinking capability. The application of hold-in range is removed from in the direct drive formula design of third axle, under the condition of forearm exhibition, satisfies the demand of the motor spatial layout of three, four-axis's arm, simultaneously, improves the articulated transmission precision of third axle and transmission efficiency.

This three, four-axis joint structure of SCARA robot includes:

one end of the second mechanical arm is an execution end, and the other end of the second mechanical arm, which is opposite to the execution end, is a connecting end;

the ball spline shaft is vertically arranged on the second mechanical arm in a penetrating mode and is positioned at the execution end;

a third axis drive unit mounted on the second mechanical arm, the third axis drive unit comprising: the base is positioned at the execution end, and the direct drive motor is arranged on the base; the direct drive motor includes: the motor comprises a nut sleeved with a ball spline shaft, a motor shaft sleeved with the nut, a rotor sleeved with the motor shaft, a stator sleeved with the rotor and a first bearing sleeved with the motor shaft; the first bearing is positioned between the motor shaft and the base; and

install the fourth shaft drive unit on the second arm, fourth shaft drive unit includes: the synchronous belt comprises a servo motor, a driving belt wheel, a spline nut, a driven belt wheel, a synchronous belt and a second bearing, wherein the servo motor is positioned between an execution end and a connecting end; the spline female is sleeved with the ball spline shaft.

The third shaft driving unit adopts direct-drive structural design, a direct-drive motor is arranged at the execution end of the second mechanical arm through the base, the direct-drive motor is a brushless direct-current torque structure, when the direct-drive motor runs, the stator is electrified and then drives the rotor to rotate, and then the motor shaft rotates and drives the nut to rotate when rotating. Along with the rotation of the nut, the ball spline shaft is driven to move along the axial direction, and the movement in the Z-axis direction is realized. The fourth shaft drive unit adopts synchronous belt drive formula structural design, and servo motor installs between the execution end and the link of second arm, through driving pulley, driven pulley, hold-in range and spline mother, drives the ball spline and rotates to realize the motion of R axle direction. Through the design, with third axle drive unit and fourth axle drive unit dislocation overall arrangement on the second arm, and third axle drive unit adopts the direct drive formula structure setting with the female combination of spline, under the prerequisite that keeps whole compactness, pull open the installation distance between third axle drive unit and the fourth axle drive unit, reduce the degree of difficulty of installation and maintenance, and under the condition that need not to carry out miniaturization improvement to each part, guarantee the small and exquisite of robot, compression cost and assurance heat-sinking capability. The application of hold-in range is removed from in the direct drive formula design of third axle, under the condition of forearm exhibition, satisfies the demand of the motor spatial layout of three, four-axis's arm, simultaneously, improves the articulated transmission precision of third axle and transmission efficiency.

In one embodiment, the third shaft driving unit further comprises a brake shaft connected with the direct drive motor and a brake connected with the brake shaft; the brake shaft is sleeved with the motor shaft. The brake shaft is driven by the brake to realize brake control on the motor shaft, and the action precision of the third shaft is improved.

In one embodiment, the third shaft drive unit further comprises a shield coupled to the base; the protective sleeve accommodates the stator and the motor shaft. The guard shield is used for protecting and directly drives the motor, improves the interference killing feature and the operational stability of equipment.

In one embodiment, the shroud comprises: the motor comprises a shell, an upper cover, a first pressing plate and a third bearing, wherein the shell is sleeved with a stator, the upper cover is connected with the shell, the first pressing plate is connected with a motor shaft, and the third bearing is located between the upper cover and the first pressing plate. First clamp plate is used for spacing to the motor shaft, improves the operating stability of motor shaft, and shell and upper cover are used for forming the protective cover body.

In one embodiment, the fourth shaft driving unit further comprises a speed reducer connected to the servo motor. The speed reducer is used for improving the output torque of the servo motor.

In one embodiment, the fourth shaft driving unit further comprises a base connected with the speed reducer; the servo motor and the speed reducer are installed on the second mechanical arm through the base. The servo motor and the speed reducer are installed on the second mechanical arm in a stacked mode through the engine base, the occupied space of the second mechanical arm in the length direction can be reduced, and component layout and heat dissipation are facilitated.

In one embodiment, the second mechanical arm is provided with a containing groove for containing the synchronous belt. The holding tank can hide the hold-in range in the second arm for the overall arrangement of part is compacter, and stability is better, is favorable to miniaturized design.

In one embodiment, the base, the direct drive motor and the servo motor are all located above the second mechanical arm, so that the occupied space below the second mechanical arm is reduced, and more operation space is provided for the gripper of the robot.

In one embodiment, the second mechanical arm is provided with a second pressure plate for the ball spline shaft to pass through; the second pressing plate is positioned below the execution end. The second clamp plate is used for shielding the joint of the ball spline and the second mechanical arm, plays a role in protection, and can play a role in supporting in the Z direction.

And simultaneously, the utility model also provides a SCARA robot.

The SCARA robot comprises a three-axis joint structure and a four-axis joint structure of the SCARA robot in any embodiment.

Above-mentioned SCARA robot, its third, four-axis joint structure has carried out the improvement setting, and third axis drive unit adopts direct drive formula structural design, will directly drive the motor through the base and install the execution end at the second arm, should directly drive the motor and set up for brushless direct current torque structure, and when directly driving the motor operation, the stator circular telegram back, the drive rotor rotates, and then drives the motor shaft and rotates, and the motor shaft drives the nut and rotates when rotating. Along with the rotation of the nut, the ball spline shaft is driven to move along the axial direction, and the movement in the Z-axis direction is realized. The fourth shaft drive unit adopts synchronous belt drive formula structural design, and servo motor installs between the execution end and the link of second arm, through driving pulley, driven pulley, hold-in range and spline mother, drives the ball spline and rotates to realize the motion of R axle direction. Through the design, with third axle drive unit and fourth axle drive unit dislocation overall arrangement on the second arm, and third axle drive unit adopts the direct drive formula structure setting with the female combination of spline, under the prerequisite that keeps whole compactness, pull open the installation distance between third axle drive unit and the fourth axle drive unit, reduce the degree of difficulty of installation and maintenance, and under the condition that need not to carry out miniaturization improvement to each part, guarantee the small and exquisite of robot, compression cost and assurance heat-sinking capability. The application of hold-in range is removed from in the direct drive formula design of third axle, under the condition of forearm exhibition, satisfies the demand of the motor spatial layout of three, four-axis's arm, simultaneously, improves the articulated transmission precision of third axle and transmission efficiency.

Drawings

Fig. 1 is a schematic view of a three-axis and four-axis joint structure of a SCARA robot according to a first embodiment of the present invention;

FIG. 2 is a schematic view of another perspective of the three and four axis joint configuration of the SCARA robot shown in FIG. 1;

FIG. 3 is a top view of a three-and four-axis joint structure of the SCARA robot shown in FIG. 2;

FIG. 4 is a cross-sectional view taken along the line A-A of the three-and four-axis joint structure of the SCARA robot shown in FIG. 3;

FIG. 5 is a partial view of a three and four axis joint configuration of the SCARA robot shown in FIG. 1;

fig. 6 is a schematic view of a three-axis and four-axis joint structure of a SCARA robot according to a second embodiment of the present invention;

fig. 7 is a sectional view of a three-and four-axis joint structure of the SCARA robot shown in fig. 6.

The meaning of the reference symbols in the drawings is:

the three-axis and four-axis joint structure of the 100-SCARA robot;

10-a second mechanical arm, 11-an execution end, 12-a connecting end, 13-a containing groove, 14-a second pressing plate and 15-a third pressing plate;

20-a ball spline shaft;

30-third shaft driving unit, 31-base, 32-direct drive motor, 321-nut, 322-motor shaft, 323-rotor, 324-stator, 325-first bearing, 33-brake shaft, 34-brake, 35-shield, 351-shell, 352-upper cover, 353-first pressure plate, 354-third bearing, 36-encoder, 361-code disc shaft, 362-hollow code disc, 363-reading head mounting seat.

40-a fourth shaft driving unit, 41-a servo motor, 42-a driving belt wheel, 43-a spline nut, 44-a driven belt wheel, 45-a synchronous belt, 46-a second bearing, 47-a speed reducer and 48-a machine base.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise. In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Example one

As shown in fig. 1 to 5, it is a three-axis and four-axis joint structure 100 of a SCARA robot according to a first embodiment of the present invention.

As shown in fig. 1 to 3, the three-and four-axis joint structure 100 of the SCARA robot includes: the robot comprises a second mechanical arm 10, a ball spline shaft 20 vertically penetrating the second mechanical arm 10, a third shaft driving unit 30 installed on the second mechanical arm 10, and a fourth shaft driving unit 40 installed on the second mechanical arm 10. Wherein the second robot arm 10 is adapted to carry the ball spline shaft 20, the third axis drive unit 30, and the fourth axis drive unit 40, and in use, is articulated with the first robot arm of the SCARA robot. The ball spline shaft 20 is used for connecting a gripper of the SCARA robot, and the ball spline shaft 20 can realize a screw structure required by a Z axis and a spline structure required by an R axis, and the movement of a third axis and a fourth axis of the SCARA robot is realized under the driving of the third axis driving unit 30 and the fourth axis driving unit 40.

Hereinafter, the three-axis and four-axis joint structure 100 of the SCARA robot will be further described with reference to fig. 4 and 5 on the basis of fig. 1 to 3.

As shown in fig. 4, in the present embodiment, the second robot arm 10 is disposed in a substantially straight shape, and is placed in a substantially horizontal posture when in use. One end of the second mechanical arm 10 is an execution end 11, and the other end of the second mechanical arm 10 opposite to the execution end is a connection end 12, for example, taking the posture shown in fig. 4 as an example, the execution end 11 is located at the left end (or referred to as the outermost end) of the second mechanical arm 10, and the connection end 12 is located at the right end (or referred to as the innermost end) of the second mechanical arm 10. The execution end 11 is used for installing a ball spline shaft 20 to butt the gripper of the SCARA robot, and the connection end 12 is used for hinging a first mechanical arm of the SCARA robot.

As shown in fig. 4, the ball spline shaft 20 is located at the execution end 11, and is provided through the execution end 11 in a direction perpendicular to the longitudinal direction of the second robot arm 10 (perpendicular to the plane on which the second robot arm 10 is located). The advantage of using a ball spline shaft 20 is that: the rolling groove of the ball is precisely ground and formed by Goldd type 40 degree angle contact, and has large load capacity in radial and torque directions because of large contact angle. The rotating direction has zero clearance, the spline shaft is combined with the spline outer cylinder by adopting 2-4 rows of ball rows with 40-degree contact angles, and the clearance in the rotating direction can be zero by adjusting a prepressing mode. High sensitivity, and the special design of the steel ball contact point, which has more sensitivity besides high rigidity, and can reduce the energy waste. High rigidity, high contact angle, high rigidity, and optionally, a suitable preload, and thus high torque rigidity and moment rigidity can be obtained. The assembly is simple, and the steel balls can not fall off even the spline outer cylinder is separated from the spline shaft due to the adoption of a special design. Therefore, the assembly, maintenance and inspection are easy to be carried out. Note that the ball spline shaft 20 in the present embodiment is a simple schematic view.

As shown in fig. 4 and 5, the third shaft driving unit 30 includes: a base 31 at the actuating end 11 and a direct drive motor 32 mounted on the base 31. Wherein, the direct drive motor 32 includes: a nut 321 for engaging with the ball spline shaft 20, a motor shaft 322 for engaging with the nut 321, a rotor 323 for engaging with the motor shaft 322, a stator 324 for engaging with the rotor 323, and a first bearing 325 for engaging with the motor shaft 322. The first bearing 325 is located between the motor shaft 322 and the base 31. When the stator 324 is powered on, the driving rotor 323 rotates, and then the motor shaft 322 is driven to rotate in conjunction with the nut 321 to drive the ball spline shaft 20 to lift, so as to realize Z-axis motion. The direct drive motor 32 is simple in structure, small in size, light in weight and capable of compressing occupied space of components. In addition, the direct drive motor 32 can directly drive the load, so that errors caused by tooth gaps and elastic deformation of materials due to transmission of the synchronous belt 45 are avoided, and the transmission precision and the transmission efficiency are higher.

It is considered that the control of the ball spline shaft 20 becomes unstable and inaccurate due to inertia when the direct drive motor 32 is stopped from rotation. Accordingly, a corresponding brake mechanism may be provided on the third shaft drive unit 30. For example, as shown in fig. 4 and 5, in the present embodiment, the third shaft driving unit 30 further includes a brake shaft 33 connected to the direct drive motor 32 and a brake 34 connected to the brake shaft 33, and the brake shaft 33 is sleeved on the motor shaft 322. The brake 34 drives the brake shaft 33 to realize the brake control of the motor shaft 322, and the action precision of the third shaft is improved.

In view of the fact that the SCARA robot may be exposed to various working environments, for example, environments in which splashed liquid or debris is present, a structure for protecting the direct drive motor 32 may be provided at the third shaft drive unit 30. For example, as shown in fig. 4, in the present embodiment, the third shaft driving unit 30 further includes a shield 35 connected to the base 31, and the shield 35 houses the stator 324 and the motor shaft 322. The protective cover 35 is used for protecting the direct drive motor 32, and the anti-interference capability and the operation stability of the equipment are improved.

Further, as shown in fig. 4, in the present embodiment, the shield 35 includes: a housing 351 for receiving the stator 324, an upper cover 352 for connecting the housing 351, a first pressure plate 353 for connecting the motor shaft 322, and a third bearing 354 between the upper cover 352 and the first pressure plate 353. The first pressing plate 353 is used for limiting the position of the motor shaft 322, so that the operation stability of the motor shaft 322 is improved, and the housing 351 and the upper cover 352 are used for forming a protective cover body.

As shown in fig. 4 and 5, the fourth shaft driving unit 40 includes: the servo motor 41 is positioned between the execution end 11 and the connecting end 12, the driving pulley 42 is connected with the servo motor 41, the spline nut 43 is positioned at the execution end 11, the driven pulley 44 is sleeved with the spline nut 43, the synchronous belt 45 is sleeved between the driving pulley 42 and the driven pulley 44, and the second bearing 46 is connected between the spline nut 43 and the execution end 11. The spline female 43 is fitted over the ball spline shaft 20. When the servo motor 41 operates, the electric driving pulley 42 rotates, the driven pulley 44 is linked to rotate through the synchronous belt 45, and then the spline nut 43 is driven to rotate, and the spline nut 43 drives the ball spline shaft 20 to rotate, so that the R-axis motion is realized.

In the embodiment, since the third axis driving unit 30 is disposed at the executing end 11 of the second robot arm 10, and the servo motor 41 is disposed between the executing end 11 and the connecting end 12 of the second robot arm 10, the center of gravity of the three-axis and four-axis joint structure 100 of the whole SCARA robot can be adjusted toward the connecting end 12, which is beneficial to improving the stability of the second robot arm 10 during operation. If the center of gravity of the three-axis and four-axis joint structure 100 of the SCARA robot is disposed at the executing end 11, the problem of heavy head and light feet can occur, and when the second mechanical arm 10 is connected to the first mechanical arm, the connecting end 12 of the second mechanical arm 10 bears a large load, and a large centrifugal force is generated when the second mechanical arm 10 swings, so that the stability and precision of the action of the second mechanical arm 10 are reduced, and the second mechanical arm 10 is easily damaged.

As shown in fig. 4, in the present embodiment, the second mechanical arm 10 is provided with an accommodating groove 13 for accommodating the timing belt 45. The accommodating groove 13 can hide the synchronous belt 45 in the second mechanical arm 10, so that the layout of the parts is more compact, the stability is better, and the miniaturization design is facilitated.

As shown in fig. 4, in the present embodiment, the fourth shaft driving unit 40 further includes a speed reducer 47 connected to the servo motor 41, and the speed reducer 47 is used for increasing the output torque of the servo motor 41.

Further, as shown in fig. 4, in the present embodiment, the fourth shaft driving unit 40 further includes a base 48 connected to the speed reducer 47. The servo motor 41 and the reduction gear 47 are mounted on the second robot arm 10 through a base 48. The servo motor 41 and the speed reducer 47 are mounted on the second mechanical arm 10 in a stacked manner through the base 48, so that the occupation of the space of the second mechanical arm 10 in the length direction can be reduced, and the layout and the heat dissipation of components are facilitated.

As shown in fig. 4, in the present embodiment, the base 31, the direct drive motor 32, and the servo motor 41 are all located on the second robot arm 10, so as to make more operating space above the execution end 11 of the robot, and reduce the occupied space below the second robot arm 10. As shown in fig. 4, the direct drive motor 32 and the base 31 are installed vertically upside down above the execution end 11 of the second mechanical arm 10 with the ball spline shaft 20 as the axis. And the servo motor 41, the speed reducer 47 and the base 48 are connected together in turn vertically upside down from top to bottom and are mounted between the execution end 11 and the connection end 12 of the second mechanical arm 10 through the base 48, and the servo motor 41, the speed reducer 47 and the base 48 are arranged coaxially and in parallel with the ball spline shaft 20.

As shown in fig. 4, in the present embodiment, the second robot arm 10 is provided with the second presser plate 14 through which the ball spline shaft 20 passes. The second pressure plate 14 is located below the actuation end 11. The second pressure plate 14 is used for shielding the joint of the ball spline shaft 20 and the second mechanical arm 10, and plays a role of protection, and can play a role of bearing in the Z direction.

In addition, as shown in fig. 4, in the present embodiment, the second robot arm 10 is further provided with a third pressing plate 15 connected to the driven pulley 44, and the third pressing plate 15 is located at the bottom end of the driven pulley 44 for limiting the driven pulley 44.

In this embodiment, the assembling method of the three-and four-axis joint structure 100 of the SCARA robot is as follows: the second bearing 46 is fitted into the second robot arm 10, the driven pulley 44 is fitted into the inner hole of the second bearing 46, and is fixed to the driven pulley 44 by the third pressure plate 15, the spline nut 43 and the driven pulley 44 are fixed by the screws, and the second pressure plate 14 and the second robot arm 10 are fixed by the screws. The stator 324 is pressed into the housing 351, the rotor 323 is mounted on the motor shaft 322 by adhesion, the motor shaft 322 and the rotor 323 are mounted in the housing 351, the first pressing plate 353 and the motor shaft 322 are fixed by screws, the third bearing 354 is mounted on the first pressing plate 353 and is sleeved in the third bearing 354 by the upper cover 352, the upper cover 352 and the housing 351 are fixed by screws, the first bearing 325 is mounted in the motor shaft 322, the brake shaft 33 is mounted in the nut 321, the brake shaft 33 and the motor shaft 322 are fixed by screws, the base 31 is mounted on the outer ring of the first bearing 325, the base 31 and the housing 351 are fixed by screws, and the brake 34 is fixed on the base 31 by screws. The servo motor 41 and the speed reducer 47 are fixed through screws, the speed reducer 47 is fixed on the base 48 through screws, the driving pulley 42 is arranged on an output shaft of the speed reducer 47, the synchronous belt 45 is sleeved on the driven pulley 44 and the driving pulley 42, and the tension force is adjusted. The base 48 is fixed to the second mechanical arm 10 by screws. The base 31 is fixed to the second mechanical arm 10 by screws. The ball spline shaft 20 is fitted into the nut 321 and the spline female 43.

In the three-axis and four-axis joint structure 100 of the SCARA robot, the third axis driving unit 30 adopts a direct drive type structural design, the direct drive motor 32 is installed at the executing end 11 of the second mechanical arm 10 through the base 31, the direct drive motor 32 is a brushless direct current torque structure, when the direct drive motor 32 operates, the stator 324 is electrified to drive the rotor 323 to rotate, and then the motor shaft 322 is driven to rotate, and when the motor shaft 322 rotates, the nut 321 is driven to rotate. With the rotation of the nut 321, the ball spline shaft 20 is driven to move in the axial direction, that is, the movement in the Z-axis direction is realized. The fourth shaft driving unit 40 adopts a synchronous belt 45 transmission type structural design, the servo motor 41 is installed between the execution end 11 and the connection end 12 of the second mechanical arm 10, and the ball spline is driven to rotate through the driving pulley 42, the driven pulley 44, the synchronous belt 45 and the spline nut 43, so that the movement in the R shaft direction is realized. Through the above design, with third axle drive unit 30 and the dislocation overall arrangement of fourth axle drive unit 40 on second arm 10, and third axle drive unit 30 adopts the direct drive formula structure setting of 43 combinations with the spline, under the prerequisite that keeps whole compactedness, pull open the installation distance between third axle drive unit 30 and the fourth axle drive unit 40, reduce the degree of difficulty of installation and maintenance, and under the condition that need not to carry out the miniaturization improvement to each part, guarantee the small and exquisite of robot, compression cost and assurance heat-sinking capability. The application of hold-in range 45 is removed from in the direct drive formula design of third axle, under the condition of forearm exhibition, satisfies the demand of the motor spatial layout of three, four-axis's arm, simultaneously, improves the articulated transmission precision of third axle and transmission efficiency.

Example two

As shown in fig. 6 and 7, it is a three-and four-axis joint structure 100 of a SCARA robot according to a second embodiment of the present invention.

The difference between this embodiment and the first embodiment is: in the three-and four-axis joint structure 100 of the SCARA robot of the present embodiment, the third driving unit 30 is further provided with an encoder 36 connected to the direct drive motor 32. The encoder 36 is annular as a whole and includes: a code wheel shaft 361 connected with the motor shaft 322, a hollow code wheel 362 sleeved on the code wheel shaft 361, and a reading head mounting base 363 connected with the hollow code wheel 362. The code shaft 361 is fitted over the ball spline shaft 20 and extends from the central opening of the upper cover 352 to the outside. A hollow code wheel 362 is located at a portion of the code wheel shaft 361 that extends outside the upper cover 352, and a readhead mount 363 is mounted at a central opening of the upper cover 352.

Other structures of the present embodiment are the same as those of the first embodiment, and the beneficial effects of the first embodiment can also be achieved.

And simultaneously, the utility model also provides a SCARA robot.

The SCARA robot includes the three-and four-axis joint structure 100 of the SCARA robot of the above embodiment. The SCARA robot may be installed upright or installed upside down, and the three-axis and four-axis joint structure 100 of the SCARA robot in the above embodiment is also included in the protection range of the SCARA robot in the present embodiment.

For the description of the three-axis and four-axis joint structure 100 of the SCARA robot, reference is made to the above description, and the description is omitted here.

The SCARA robot has the three-axis and four-axis joint structures which are improved, the third axis driving unit 30 adopts a direct-drive structure design, the direct-drive motor 32 is arranged at the execution end 11 of the second mechanical arm 10 through the base 31, the direct-drive motor 32 is arranged in a brushless direct-current torque structure, when the direct-drive motor 32 runs, the stator 324 is electrified and then drives the rotor 323 to rotate, so as to drive the motor shaft 322 to rotate, and the motor shaft 322 drives the nut 321 to rotate when rotating. With the rotation of the nut 321, the ball spline shaft 20 is driven to move in the axial direction, that is, the movement in the Z-axis direction is realized. The fourth shaft driving unit 40 adopts a synchronous belt 45 transmission type structural design, the servo motor 41 is installed between the execution end 11 and the connection end 12 of the second mechanical arm 10, and the ball spline is driven to rotate through the driving pulley 42, the driven pulley 44, the synchronous belt 45 and the spline nut 43, so that the movement in the R shaft direction is realized. Through the above design, with third axle drive unit 30 and the dislocation overall arrangement of fourth axle drive unit 40 on second arm 10, and third axle drive unit 30 adopts the direct drive formula structure setting of 43 combinations with the spline, under the prerequisite that keeps whole compactedness, pull open the installation distance between third axle drive unit 30 and the fourth axle drive unit 40, reduce the degree of difficulty of installation and maintenance, and under the condition that need not to carry out the miniaturization improvement to each part, guarantee the small and exquisite of robot, compression cost and assurance heat-sinking capability. The application of hold-in range 45 is removed from in the direct drive formula design of third axle, under the condition of forearm exhibition, satisfies the demand of the motor spatial layout of three, four-axis's arm, simultaneously, improves the articulated transmission precision of third axle and transmission efficiency.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above examples only represent preferred embodiments of the present invention, which are described in more detail and detail, but are not to be construed as limiting the scope of the invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. The utility model provides a three of SCARA robot, four-axis joint structure which characterized in that includes:

one end of the second mechanical arm is an execution end, and the other end of the second mechanical arm opposite to the execution end is a connecting end;

the ball spline shaft is vertically arranged on the second mechanical arm in a penetrating mode and is positioned at the execution end;

a third axis drive unit mounted on the second robotic arm, the third axis drive unit comprising: the base is positioned at the execution end, and the direct drive motor is arranged on the base; the direct drive motor includes: the motor comprises a nut, a motor shaft, a rotor, a stator and a first bearing, wherein the nut is sleeved with the ball spline shaft; the first bearing is positioned between the motor shaft and the base; and

install fourth shaft drive unit on the second arm, fourth shaft drive unit includes: the synchronous belt comprises a servo motor, a driving belt wheel, a spline nut, a driven belt wheel, a synchronous belt and a second bearing, wherein the servo motor is positioned between the execution end and the connecting end, the driving belt wheel is connected with the servo motor, the spline nut is positioned at the execution end, the driven belt wheel is sleeved with the spline nut, the synchronous belt is sleeved between the driving belt wheel and the driven belt wheel, and the second bearing is connected between the spline nut and the execution end; the spline female is sleeved with the ball spline shaft.

2. The three-axis and four-axis joint structure of a SCARA robot according to claim 1, wherein the third axis driving unit further comprises a brake shaft connected with the direct drive motor and a brake connected with the brake shaft; the brake shaft is sleeved with the motor shaft.

3. The three-and four-axis joint structure of a SCARA robot of claim 1, wherein said third axis drive unit further comprises a shroud connected to said base; the protective sleeve accommodates the stator and the motor shaft.

4. A three-and four-axis joint structure for a SCARA robot according to claim 3, wherein said shield comprises: the motor comprises a shell sleeved with the stator, an upper cover connected with the shell, a first pressing plate connected with the motor shaft, and a third bearing positioned between the upper cover and the first pressing plate.

5. The three-and four-axis joint structure of a SCARA robot according to claim 1, wherein the fourth axis driving unit further comprises a speed reducer connected to the servo motor.

6. The three-and four-axis joint structure of a SCARA robot according to claim 5, wherein the fourth axis driving unit further comprises a frame connected to the reducer; the servo motor and the speed reducer are installed on the second mechanical arm through the base.

7. The structure of claim 1, wherein the second arm defines a receiving slot for receiving the synchronous belt.

8. The three-axis and four-axis joint structure of a SCARA robot according to any one of claims 1 to 7, wherein the base, the direct drive motor and the servo motor are all located above the second mechanical arm.

9. The three-or four-axis joint structure of a SCARA robot according to claim 8, wherein the second mechanical arm is provided with a second presser plate through which the ball spline shaft passes; the second pressing plate is positioned below the execution end.

10. A SCARA robot comprising a three-and four-axis joint structure of the SCARA robot of any one of claims 1 to 9.

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