JPH0241886A - Direct driving robot - Google Patents

Abstract

PURPOSE:To increase a radiating property and to bear even a severe operation by exposing a DD motor for driving a base part arm and separating the distance with a DD motor for driving the tip arm. CONSTITUTION:A base part arm 5 and tip arm 10 are turned by driving the exposed DD motor 3 for driving the base part arm and the DD motor 27 for driving the tip provided by separating from this motor 3, and work shafts 50, 50' are planely positioned. Moreover, the rotary positioning of the work shaft is also executed by the AC motor 47 for driving the work shaft rotation. A stopper part is positioned by the AC motor 48 for driving the work shaft positioning stopper simultaneously therewith. The work shaft is then descended by operating either of air cylinders 58, 58' and the lot of this air cylinders 58, 58' is stopped at the specified height by abutting to the stopper part. The radiating property can thus be bettered by arranging the DD motor 3, 27 and a severe operation can be born without giving an adverse effect on an encoder.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a direct drive robot driven by a direct drive motor.

(Prior Art) A DD robot using a conventional direct drive (hereinafter referred to as DD) motor is disclosed in Japanese Patent Application Laid-open No. 173875/1983.

This is the first and second DD that drives the horizontal multi-joint arm.
Momo is fixed to the base of the robot, and the tip arm is connected to the second arm by a shaft passing through the hollow part of the DD motor for driving the base arm and a steel bell 1 disposed inside the base arm.
It is driven by being rotationally connected to the DD momo.

In order to support the base arm and transmit the driving force, a relatively long rotating column is pivotally supported on the outer periphery of a fixed column which pivotally supports the shirt 1 for driving the tip arm on the inside thereof. The base art t is connected to the lower end of the first DD thigh.

In addition, a long sword maintenance mechanism is provided on the pulley to maintain tension on the steel belt.

The stator and rotor of the first and second DD momos are exposed inside the cover, and are arranged in parallel in two parts.

(Problems to be Solved by the Invention) The prior art described in lIq has a structure in which the heavy DD thigh is disposed on the fixed part, so the arm becomes lightweight and the arm's mobility fjl is improved.

DD Momo--It has become popular in the United States as a practical DD robot by reducing the influence of mechanical interference of the arm, which was another problem when using it.

However, this robot has the following problems.

(1) Since a steel belt is used as the end arm drive transmission means, it is costly in terms of quality assurance, such as removing the initial elongation of the steel belt and requiring 21 bolts.

Stem) Similar to (2), a special mechanism for tensioning the steel bell 1- is required, resulting in a high cost.

(2) Since a long support is interposed between the base arm and the first DD momo, the 111 angle and torsional rigidity of the support shaft are reduced. Therefore, the servo gain of the DD momo cannot be increased. In addition, in the case of a DD robot, since there is no reduction gear, there is no damping, and if the rigidity of the arm etc. is low, a resonance phenomenon is likely to occur.

l◇ Since the first and second DD momos are arranged close to each other, heat dissipation conditions become poor. Therefore.

This adversely affects the rotation detector (encoder) located near the DD momo.

(Means for Solving the Problems) The present invention aims to solve the above problems by fixing the drive shaft to the lower surface of the first link plate disposed inside the rear part of the base arm, and The tip arm shaft is pivotally supported in the V line with the drive shaft through a bearing in one part, the tip arm is fixed to the second part of the tip arm shaft, and a second link plate is attached to the tip arm. At the same time, connect both ends of the two links to the first link plate 1 and the second link plate with a length equal to the distance between the pivot plate and the tip arm shaft, and so that their rotation surfaces do not coincide with each other. The two links are pivotally supported with a phase difference of approximately 90 degrees and parallel to the drive shaft by a pair of supports of different lengths provided on the link plate at equal distances from the center of rotation. At the same time, an output shaft of a direct drive motor for driving the base arm is fixed to the rear lower surface of the base arm so that its shaft is parallel and coaxial with the drive shaft, and the direct drive motor for driving the base arm is disposed below the output shaft. It is fixed to a fixed base, and a direct drive motor similar to the above-mentioned arm striking motor is installed in the fixed base.
A direct drive motor for driving the tip arm is provided as shown in FIG. shall be.

(Structure) A detailed description will be given below based on the illustrated embodiment. A flange 2 is fixed to the upper part of a fixed base 1. The fixed base 1 has a base arm As 19g dynamic direct (hereinafter referred to as DD).
A stator portion 3a of the motor 3 is fixed. There is a spacer 4 on the top of the rotor of the DD momo-3. j
The spacer 4 has a rear (base) part 5 of the base arm 5.
a is fixed.

On the other hand, at the end 5b of the base arm 5 on the side opposite to the base arm drive DD motor 3, a support member 6 is extended in the longitudinal direction of the arm so that its position can be adjusted perpendicularly to the output shaft of the base arm drive DD motor 3. It is fastened to the base arm 5 by bolts in the holes. A cross roller bearing 8 is fixed to the support member 6 by a presser plate 7,
The cross roller bearing 8 supports the tip arm shaft 9 in parallel with the output shaft of the DD motor 3 for driving the base arm. 1
0 is the tip arm connected to the tip arm shaft at its rear.

Further, a distal arm drive shaft 11 is coaxially supported on the spacer 4 by bearings 12a and 12b, coaxially with the output shaft of a DD motor for driving the base arm. A first link plate 13 is connected to the protruding end of the distal arm drive shaft 11 in the base arm 5 by fitting the jIx fitting hole 13a into the fitting shaft 11a of the distal arm rotation shaft 11. Also, a second link plate 14 is provided on the base arm 5 side of the distal arm shaft 9.
The fitting hole 14a is fitted into the fitting shaft 9a of the distal arm shaft 9, and the fitting shaft 9a is connected to the fitting hole 14a. Fitting holes 15, 16° and 17.18° are bored in each of the facing surfaces of the first link plate 13 and the second link plate 14 at a distance of r2, r11r2' from the center of rotation of the link plate. . This fitting hole 15° 16, 17, 18 and the fitting hole 13a, 1
4a is the first link plate 13 and the second link plate 1
4 are manufactured by simultaneous machining, so the distance from each rotation center is 'L=rL' + r2:= r+
2. Also, the angle α=β. Fitting holes 15, 16
and 17.18 have a pair of link shafts 1 with different lengths, respectively.
5a, 16a and 17a, 18a are attached parallel to the tip arm pivot shaft 11.

Long link shaft 15a, short link shaft 17a, short link shaft 16
a and the long link shaft 18a are bearings 19a, 20a, 19b.
, 20b, 19c, 20c, 19d, 20
d by links 21 and 22, respectively. The link 21 and the link 22 are connected to the link plate 13.
The rotating surfaces are different so that there is no interference even when 14 rotates.

Further, the links 21 and 22 are simultaneously machined so that the distance between the respective axes is equal to 1e1+ez. ell again
82 has a design dimension equal to the distance between the axes of the base arm 5.

In addition, each of the links 21 and 22 has a disc spring 23 and 24 inserted between two bearings, and a presser plate 25.
By one ball of the outer ring of the bearing.

A preload is set across the inner ring of the bearing, the disc spring, the inner ring of the bearing, the ball, and the outer ring of the bearing. 26 is a screw that fastens the presser plate 25 to the link 21.22.

The shaft supports at both ends of each link 21 and 22 are preloaded as shown in Fig. 7, and at least one shaft support is aligned in the axial direction, so the link shaft and the link (inside the bearing) are axially aligned. It is possible to move in the direction.

Note that 27 and 28 are lids attached to the base arm 5 and used during assembly.

Further, the diameters of the fitting holes 13a and 14a, L5a and 17a, 16a and 18a, and the bearing holes of the links 21 and 22 are the same.

On the other hand, inside the fixed base 1, a stator 27a of a DD motor 27 for driving the tip arm is fixed to the bottom 1a of the fixed base 1. The output shaft (rotor) 27b of the tip arm drive DD motor 27 is connected to the tip arm drive shaft 11.
It is installed so that it is coaxial with the D for tip arm drive
The output shaft 27b of the D motor 27 is the tip arm shaft 11.
It is fastened to a flange 28 connected to the lower end 11b of.

A gap is provided between the flange 28 and the flange 2. Further, a hollow shaft portion 4a is formed in the lower part of the spacer 4, passing through between the hollow portion 3d of the base arm driving DD motor 3 and the tip arm folding shaft 11,
A downwardly protruding portion 4a of the flange 2 of the hollow shaft portion 4a
' A block 30 is connected within the gap. The block 30 is pivotally supported by the flange 28 via a bearing 32. 23 and 24 are bearings; disk springs that apply preload to 32;

A mechanical stopper for restricting the rotation of the base arm is formed on the movement block 30 and comes into contact with a fixed stopper 33 fixed to the flange 2. Further, the block 30 is provided with a dog 34, and the flange 2
The origin is fixed to the brackets 1 to 35 provided in the base arm for detecting the rotation angle of the base arm, and the proximity switches 3G, 37, and 38 for overrun detection are used to detect the rotation angle of the base arm. A relay box 40 is provided on the back of the fixed base 1 and is provided with a connector 39 for connecting to a controller (not shown).

Furthermore, a support column 41 for wiring is attached to the upper surface of the fixing table between the relay box 40 and the flange 2. Applicable! 1 [!
One end of a flexible conduit tube (hereinafter referred to as a conduit tube) 43 is connected to the upper end of the wire support 41 via a rotary connector 42 .

The other end of the conduit tube 43 is provided at the rear upper part of the distal arm 1o so as to be approximately coaxial with the distal arm 9, and is connected to the distal arm 10 via a rotary connector 45 provided on the upper part of the cover 44. ing.

Inside the tip arm 10, an AC motor 47 for driving the rotation of the work shaft equipped with a speed reducer 46, and A and C motors 48 for moving the work shaft positioning stopper are provided at 1 and the row tip arm shaft 9. The AC motor 47 is provided to be substantially coaxial with the tip arm shaft 9, and a timing pulley 48 is attached to the output shaft 46a of the reduction gear 1 46, and a timing pulley 49 is attached to the output shaft 48a of the AC motor 48, which will be described later. It is connected.

On the other hand, spline bearings 51 and 51' are installed in the front part of the distal arm 10 so that a pair of working axes 50°50' formed by splines are parallel to the distal arm axis 9.
, 52.52', radial bearing 53.53', 54
．． 54', it is slidably and rotatably supported in the axial direction.

The spline bearings 5], 5]', 52.52' are connected to the timing pump=υ-56 via sleeves 55.55'.
It is connected to +56'. The timing pulleys 56, 56' and the timing pulley 48 are rotationally connected by a timing belt 57.

Further, the upper ends 50a, 50a' of the working shafts 50, 50' are connected to a lot 5 of a pair of air cylinders 58.58' provided at the upper front part of the tip arm 10 in parallel with the working shafts 50, 50'.
Joint 59.59' connected to 8a, 58a'
It is provided so as to be rotatable and integral in the axial direction by bearings 60, 60' provided in the.

On the other hand, the working shaft 50° 50' in the front part of the tip arm 10 is connected to the working shaft 4' 11150, 50 through bearings 61, 62.
A sleeve 63 is pivotally supported in parallel with '. A timing pulley 64 is formed in the sleeve 63 above the bearing 61, and the timing pulley 49
The bearing 67 is rotatably connected to the timing belt 65 by a timing belt 65, and a bearing 67 having a female thread that fits into the male thread of a sliding stopper 66 whose outer periphery is threaded is fixed at the upper part thereof. Reference numeral 68 denotes a stopper portion formed on the upper part of the sliding stopper 66, and is guided in a slidable but non-rotatable manner by a guide 69 fixed downwardly to the axis of the sleeve 63 inside the distal end art tslO. Reference numeral 70 is a cover provided at the front part of the tip arm 10.

Note that the cover 70, cover 44, relay box 40, lids 27, 28, support member 6, etc. have a structure that seals the inside of the robot from the outside.

70, 71, and 71' are proximity switches for origin and overrun detection for detecting the rotation angle of the tip arm.

Further, 72 is a mechanical stopper for the tip arm fixed to the rear part 5a of the base arm 5, and is adapted to stop the first linter plate 1 when the tip arm overruns.

In the present invention, a mechanical stopper 72 for the tip arm and a mechanical stopper 33 for the base arm are provided inside the robot. Therefore, safety is improved, and even if the robot overruns and comes into contact with the mechanical stopper, the dust generated by the contact will not be released to the outside, making it possible to use it even in environments where cleanliness is required.

Although a block 30 with a mechanical stopper and a fixed stopper 33 were provided in the gap between the flange 2 and the flange 28, a D for driving the tip arm was provided instead of the stopper.
A brake for stopping the rotation of the output shaft 27b of the D motor 27 and the hollow shaft portion 4a may be provided on the flange 2 or the fixed base. Moreover, in this case, one brake means can simultaneously control the output shaft 2 of the DD motor for driving the tip arm.
7b and the hollow shaft portion 4a may be stopped.

Note that a working tool (not shown) is attached to the lower ends 50b, 50b' of the working shaft 50, 50'.

Further, 73 is a cable that is inserted into the conduit tube 43 and connects the relay box 40 and the distal arm 10. Since no heavy parts are installed in the base arm 5, there is no risk of cable breakage even if the links 21 and 22 rotate.

Of the two sets of parallelogram link mechanisms, links 18 and 19
Since the lengths ate and ez are processed at the same time, they are equal.

Also, the rotation center of the link plate 10.11 and the link 18
．． Center distance of 19 shaft supports f'i'II'ty r,+
Since rz+rz' is also processed at the same time, they are equal.

In addition, since the support member 5 has a structure that allows the position to be adjusted during assembly, the distance between the axes of the base arm can be adjusted to L=e□(e2
), the rotation of the distal arm shaft 3 is transmitted to the distal arm shaft.

In addition, the distance between the axes of link 18, 19 and base arm 2 e□
It is possible to simultaneously machine the two links and the base arm so that +ez*L' is equal, but since the sizes of the link and base arm and the diameter of the machined hole are extremely different, it is actually necessary to machine them simultaneously. It is impossible to do so.

In addition, in the link shaft support, the link (bearing inner ring) can move in the axial direction with respect to the link shaft at least at one end, so it is possible to absorb processing errors and assembly errors of one part, and precision This enables effortless rotation transmission.

At the same time, since a preload is set on the link shaft support, a decrease in rigidity in the link shaft support (bearing) is prevented. In particular, if there is a part with low rigidity in the drive transmission system, the natural frequency will be small, so this is effective because the direct drive motor, which requires a high natural frequency, is used as the driving source.

Also, the lids 27 and 28 are located at the rear of the base arm 5 (
It is provided to seal the holes formed in the upper part of the base part and the lower part of the front part.

These two holes are work holes for assembling the links 21, 22, etc. into the base arm 5, but the base arm has a closed structure except for these holes and the shaft support opposite to the holes, so the high arm Rigidity can be obtained (normally, arms with built-in links have a structure where one side of the arm is completely spaced, so rigidity is low.)

Further, an exhaust tube may be provided in the conduit tube 43 to suck in dust generated inside the robot from the outside. Since the conduit tube 43 is connected at one end to the approximate center of rotation of the distal arm 10 by a rotating connector, it can easily follow the rapid movement of the arm (conventionally, the resistance caused by bending or twisting the wiring attached to the arm (There was a problem with accuracy deterioration due to this.)

Next, we will discuss the effect.

By rotating the base arm drive DD motor 3 and the tip arm 1 cantering DD motor 27, the base arm 5 and the tip arm 10 are rotated, positioning the work shaft 50, 50' in a plane, and AC for shaft rotation drive
The motor 47 also performs rotational positioning of the work shaft. At the same time, the stopper portion 68 is positioned by the working axis positioning stopper active AC motor 48.

Next, actuate one of the air cylinders 58.58' to lower the working shaft 50.50', and the rod 58 a p 58 of the air cylinder 58.58' will be at the desired height.
a' comes into contact with the stopper portion 68 and stops.

(Effects) As described above, according to the present invention, the drive shaft is fixed to the lower surface of the first link plate disposed inside the rear part of the base arm, and the tip arm shaft is fixed to the upper part of the front part of the base arm via a bearing. The shaft is supported in parallel with the 1'J moving shaft, the tip arm is fixed to the upper part of the tip arm shaft, the second link plate is fixed to the tip arm shaft, and the distance between the drive shaft and the tip arm shaft is Both ends of the two links are connected to the first link plate and the second link plate, respectively, with a pair of different lengths, which are provided at equal distances from the rotation center so that the rotation surfaces of the two links do not coincide with each other. The two links are supported by two sets of supports so that the phase difference between the two links is approximately 90 degrees and parallel to the drive shaft, and the output shaft of the direct drive motor for saliva motion of the base arm is mounted on the rear lower surface of the base arm. Is the axis 1)? 1. The direct drive motor for driving the base arm is fixed so as to be parallel and coaxial with the drive shaft, and the direct drive motor for driving the base arm is fixed to a fixed base disposed below the base arm, and the direct drive motor for driving the base arm is fixed within the fixed base. A direct drive motor for driving the tip arm is provided coaxially with the direct drive motor for driving the tip arm, and the lower end of the first brother driving shaft that passes through the hollow part of the direct drive motor for striking the base arm is fixed to the output shaft of the direct drive motor for driving the tip arm. Because of this feature, the tip arm can be driven by a double link mechanism, ensuring stable accuracy without deterioration over time.

In addition, the base arm 5 and the bearing that pivotally supports the base arm 5 (
Since the distance between the base arm drive DD motor 3 (which shares the bearings) is short, high rigidity can be obtained with respect to bending and torsion related to the shaft support of the base arm 5.
The D motor 3 is exposed and the distance from the DD motor 27 for driving the tip arm is small, and it is connected to a fixed base with a large surface area, so it has good heat dissipation conditions and can withstand even severe operation. , the structure is simple, so the I
) It has the advantage of being able to supply D robots.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of one embodiment of the present invention, Fig. 2 (12I), Fig. 3 is an enlarged view of the main part of Fig. 1, Fig. 4 is an external side view of Fig. 1, and Fig. 5 is the same plane. Fig. 6 is a plan view of the link part in Fig. 1, and Fig. 7 is a front view of the shaft support of the link part in Fig. 6. 1...Fixing base 3...Base arm 19 [j Direct motor for dynamic use 5・
...Base arm 9...Tip arm shaft 10...Tip arm 11...Tip arm beating shaft 13...First link plate 14...Second link plate 1-21.22... Link 27...Direct motor 27b for tip arm disuse
・・・Output shaft

Claims (1)

[Claims] A drive shaft is fixed to the lower surface of a first link plate disposed in the rear part of the base arm, and a tip arm shaft is supported parallel to the drive shaft via a bearing in the upper front part of the base arm. Fix the tip arm to the top, fix the second link plate to the tip arm shaft,
Attach both ends of the two links to the first link plate and the second link plate at a distance from the center of rotation so that the length is equal to the distance between the drive shaft and the tip arm axis, and their rotation surfaces do not coincide with each other. is supported by a pair of equally provided supports with different lengths so that the phase difference between the two links is approximately 90 degrees and parallel to the drive shaft, and a base is attached to the rear lower surface of the base arm. The output shaft of the direct drive motor for driving the arm is fixed so that its shaft is parallel and coaxial with the drive shaft, and the direct drive motor for driving the base arm is fixed to a fixing base disposed below the base arm drive direct drive motor. A direct drive motor for driving the tip arm is installed in the stand so as to be coaxial with the direct drive motor for driving the base arm, and a hollow part of the direct drive motor for driving the base arm is connected to the output shaft of the direct drive motor for driving the tip arm. A direct drive robot characterized by a fixed lower end of the drive shaft that passes through it.