JPS62246488A - Industrial robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to industrial robots.

[Conventional technology]

In recent years, automation of assembly work through the introduction of robots in production processes has progressed rapidly. An example of a conventional industrial robot used for this purpose is shown in FIG.

This robot has a two-joint horizontal structure with a first arm 1 and a second arm 2. A DC motor 3 is provided at the base of the first arm 1 to directly drive the first arm 1, and a DC motor 3' is provided at the base of the second arm 2 which is pivotally supported at the tip of the first arm to directly drive the second arm 1. The configuration is such that it is directly driven. An air cylinder 4 is provided at the tip of the second arm 2, a vertical shaft 5 is attached to the tip of the piston rod, and a hand 6 is pivotally supported at the lower end of the vertical shaft 5. Therefore, the hand 6 is moved up and down by the expansion and contraction of the air cylinder 4. Further, a stepping motor 8 fixed to the base 7 causes a timing belt 9, 9.9 and warped pulleys 10, 10.10.

The rotational force is transmitted to the node 6 through the node 10 to perform a twisting motion.

The above-mentioned robot (Fig. 1) has two degrees of freedom in the horizontal plane by the first arm 1 and the second arm 2, and one degree of freedom in the vertical direction.
It has a total of four degrees of freedom, including one degree of freedom for twisting the hand, and is used as a work button to assemble parts from above.

[Problem that the invention seeks to solve]

The conventional industrial robot described above has the following two drawbacks.

The first drawback is that since the vertical movement of the hand is driven by an air cylinder, arbitrary positioning in the vertical direction is not possible. If a mechanical stopper is provided, the stop position can be accurately set at the end of the stroke of vertical movement, but if the stop position is to be changed, the stopper position must be corrected, so it is not possible to immediately respond to changes in the movement pattern.

The second drawback is that the twisting shaft of the hand is driven by a drive system equivalent to direct connection to the stepping motor, which tends to cause distortion of the stepping motor and is difficult to control.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the conventional robots described above, and to provide an industrial robot that can stop the vertical movement of its hand at any position with high precision. .

[Means for solving problems]

That is, in order to achieve the above object, the present invention provides a base, a first arm supported on the base so as to be able to swing around a first vertical axis, and a swingable arm of the first arm. A second arm is supported so as to be able to swing around a second horizontal axis, and a fifth vertical axis provided at the tip of the second arm moves up and down. a first member supported for rotation relative to the 8g10 member about a fourth vertical axis parallel to the third vertical axis;
a member for rotating the second member; a first drive means connected to the second member; a first drive means for moving the first member up and down along the first vertical axis; a second driving means connected to the member; and a second driving means connected to the twelfth member;
The industrial robot is characterized in that it is equipped with connecting means provided to connect the upper and lower ends of the second member, and a hand attached to the lower end of the second member.

[Effect]

With the above structure, the second member is accurately positioned in the vertical direction without being tilted, and furthermore, the second member can be rotated by a predetermined amount, so that a wrist mechanism most suitable for assembly work can be obtained.

〔Example〕

Hereinafter, one embodiment of the invention will be described with reference to FIGS. 2 to 7.

FIG. 2 is a side view of an embodiment of the industrial robot according to the present invention, and FIG. 3 and the fourth factor are the same (this is a side view cut at the center).

This robot has a three-degree-of-freedom configuration with a two-joint structure consisting of a first arm 11 and a second arm 12, and does not control the rotation of the hand 15, but has a mechanism to keep the posture (ground angle) of the hand 15 constant. have. Note that a four-degree-of-freedom configuration that also controls 130 rotations of the hand will be described later.

The first arm 11 has a two-part structure, and the lower part of the first arm 11'
is directly driven via a reducer 31 by a DC servo motor 21 installed on a base 20 coaxial with the pivot shaft,
The first upper arm 11' is rotatably supported around its pivot axis, and the first arm 11'' and the first arm 11'' are
A second arm 12 rotatably supported by the arm 11 is sandwiched between the arms 11 and connected by a shaft 15.

The second arm 12 has a base 20 coaxial with the pivot shaft of the first arm 11.
The output of the DC Chibo motor 22 installed in K is transferred to the reducer 32.
It is configured so that it can be connected to the double crank 42 via.

Here, the output shaft 18 of the double crank 42 is
1' is rotatably supported. The above-mentioned double crank 42 is composed of two cranks 42 having a phase difference of 90° on the same diameter with respect to the output shaft 169, as shown in FIG.
a and 42b are provided. Correspondingly, two cranks 7124, 1 are also connected to the base of the second arm 12 and have a phase difference of 90 degrees on the same diameter with respect to the second shaft 17 that pivots the arm.
2b is provided. And the same as the crank bin 42cL
2a are connected by a connecting rod 52tL, and the crank bin 42b and the crank bin 12b are connected by a connecting rod 52b to form a double link mechanism.

The outline of the hand mechanism is that a pair of upper and lower bases 64a, 64b are connected via a rack 62, and the pair of bases 64α,
A spline shaft 65 is rotatably supported by the spline shaft 64b as described below, and the hand 13 is attached to the lower end of the spline shaft 65 to form a tool holding shaft.

A pair of upper and lower bases 64a and 64b rotatably support rotating platelets 74cL and 74b, respectively, and the upper and lower ends of the spline shaft 65 are respectively connected to the rotating platelets 74cL and 74b. aa, adheres to 74b. Due to this K, the spline shaft 65 is rotatably supported around the third axis AA. Further, a bearing holder 67 is fixed to the tip of the second arm 12 so as to support a spline bearing 66 for slidingly guiding the spline shaft 65 so as to be rotatable about the third shaft AA. A sprocket 45, through which the spline shaft 65 is inserted, is fixed to the spline bearing 66. This is from K.
A hand mechanism supporting the hand 13 is rotatably supported at the tip of the second arm 12, and the hand 13 is configured to be moved up and down via a rack 62, as will be described in detail below. The rack 62 warped spline shaft 65 has bellows 6 for dust prevention.
I covered it with 8.

A DC Nervo motor 23 is installed at the base of the second arm 12,
The rotational output is transferred to the shaft 55. The rotation of the bevel gear 60eL is transmitted to the bevel gear 60α through the cup ring 54, and the rotation direction of the bevel gear 60eL is changed by 90° by the bevel gear 60b, and the rotation direction of the bevel gear 60eL is changed by 90°,
, is said to the binion 61b in sequence, and the rack 62 is moved to the upper F.
configured to drive. The vertical movement guide of the rack 62 is
The spline shaft 65 is provided with a warp spline bearing 66, the roller 65tL is used to prevent the rack 62 from rotating around the third axis AA, and the roller 65b is provided with a pinion 61b.
It is configured as a support for the rack 62 for engagement with. As a result, the rack 62 is moved up and down, and the upper and lower bases 64G and 64b are fixed to the rack 62.
is moved up and down, and the hand 13 is driven up and down. The vertical movement of the hand 13 is driven by the DC Nervo motor 23 via the rack 62 and the pinion 61b, so it can be freely moved up and down and stopped accurately at any position. Any means such as a combination of a feed screw and a nut may be used as means for converting the above rotational motion into linear motion.

Next, the hand 130 rotation mechanism will be explained. base 20
45'' to the second shaft 16 via a chain 54'.
A sprocket 45'K is freely rotatable about the shaft 15 which is coaxial with the shaft 17, and the sprocket 45' is connected to the sprocket 45 via a chain 54'.

Since the sprocket 45 is fixed to the spline bearing 66, the hand 13 can be rotated via the spline shaft 65 by rotating the sprocket 45. Here, since the sprocket 45' is fixed to the base 20, 150 rotations of the hand cannot be controlled, but the first arm 11. Regardless of the rotation of the second arm 120, the mechanism is such that it always maintains a constant angle with respect to the base 20.

If the assembled parts have no direction, 3 as above
A degree-of-freedom robot is sufficient, but if it becomes necessary to also control the hand 15, the robot described below can be easily constructed into a four-degree-of-freedom robot.

As shown in FIG. 7, a DC nervous motor 2 is mounted on the base 20.
4 is installed, its rotation is reduced by a reducer 34, and the base 20 is
The sprocket 45' which had been fixed to the sprocket 45' is made free, and two ports 44' are added to the sprocket 45' so that the sprocket 45' can rotate and twist the hand. The reason why a chain is used as the power transmission element for this twisting operation is to facilitate maintenance. In other words, when an endless member such as a toothed belt is assembled, it is necessary to disassemble the shaft portion. However, since a chain is not endless, the chain can be assembled and removed without leaving the shaft intact.

Finally, the features of the link mechanism will be explained.

In Figure WJ6, the double crank 42 rotated by the DC Chibo motor 22 has two transmission paths, ie, crank bins 42a, with a 90 degree difference between them.

Connecting rod 52a, crank bin 12” & crank bin
42b, the connecting rod 52b, and the crank pin 12b to drive the second arm 12. Therefore, the second arm 12 can be rotated over a wide range without having to worry about problems unlike in the case of a single crank. In this embodiment, rotational drive of approximately 300° is possible.

Moreover, the double link mechanism is connected to the crank and 742a.
, 42b, 12b, and 12g move so that they are always located at the vertices of the parallelogram. Therefore, when the first arm 11 is rotated while the double crank 42 remains stationary, the second arm 12 moves in parallel along the second axis 17 which is the central support axis.

As described above, since the second arm 12 moves in parallel and the drive motor is installed on the base 20, the moment of inertia of the rotating portion of this robot is significantly smaller than that of conventional robots. Next, the principle will be explained using FIGS. 8 and 9.

Figure 8 schematically represents the case where the 1st n1 of the conventional robot shown in Figure 1 rotates by an angle -, where 2 is the second arm, Machi is the concentrated mass of the first arm 1, and Machi is The mass of the second arm drive motor 3', #I5, is the concentrated mass of the second arm 2, and #I5 is the concentrated mass of the hand mechanism. The lengths of the first arm 1 and the second R2 are both 2α.

When the first arm 1 is rotated by an angle I, the second arm 2 is also rotated by an angle -. Therefore, the moment of inertia J of the first arm 1 is J = -1r+ +"2r2+chors+aara
becomes. However, rl is the turning radius of the town, r2 is the turning radius of the town, rs is the turning radius of the town, and r4 is the turning radius of the town.

FIG. 9 is a diagram schematically showing the case where the first arm 11 of the embodiment rotates by an angle θ.

As explained in FIG. 6, in the assembly robot according to the present invention, when the first arm rotates by an angle, the second arm moves in parallel along the second axis. Therefore, the radius of rotation of the second arm is not equal to the sum K of the length of the first arm. Therefore, the moment of inertia J' of the first arm 11 is J=(10 towns) rr10 towns r3+mara.

The town is the mass of link 10.

Now, if we compare the moments of inertia in Figures 8 and 9, assuming that the lengths of the first and second arms are both 2a, we get: J = -t Q + -2 (2a) + - (34) + −
(4a) 2 = (town + 4 books 2 + 9 town + 14a4) a'J =
(Town+1115)α+6(2α)+−(2α)2=(
1+4ms-f-4ms+rsss) a" design common sense K '2 > town, so obviously J >> J
' becomes.

For example, −+=5FrP, −2=5”pg −5
=4'b*aa=5Kp, 55=1KP, 2a
Estimated as = Q, 4sl Temilt, J = 4.04
KPm, J =: 13+51jm, and by applying the present invention, the moment of inertia of the first arm becomes approximately 4 compared to the conventional robot.

From this, when the present invention is applied, the drive motor for the first arm can be made to have a significantly smaller capacity at the same operating speed as the conventional one. Furthermore, if the drive motor for the first arm is made to be the same as the conventional one, the operating speed will be significantly faster.

〔Effect of the invention〕

As explained above, according to the trap of the present invention, the vertical movement of the hand attached to the second member can be stopped at a desired position with high precision, resulting in an excellent practical robot that is most suitable for assembly work. produce a positive effect.

[Brief explanation of drawings]

FIG. 1 is a front view of a conventional two-jointed industrial robot, and FIGS. 2 to 7 show an industrial robot according to an embodiment of the present invention, and FIG. 2 is a front view. , FIG. 3 and FIG. 4 are central sectional views of FIG. 2, FIG. 5 is a plan view of the tool holding shaft drive portion, and FIG. 6 is a plan view of the double link portion.
FIG. 7 is a front view of the tool holding shaft rotation drive motor section. FIG. 8 is a schematic diagram showing a conventional industrial robot mechanism, and FIG. 9 is a schematic diagram showing a link mechanism of an industrial robot according to an embodiment of the present invention. 11...first arm, 12...second arm, 20.
...Base, 21, 22.23.24...Drive motor, 42...
Double crank, 52a, 52b... Connection rod of double link mechanism, 5
4, 54', 54'...Chain, -608, lb
...Bevel gear, 614. dlb - Spur gear, 62 - Rack, 65 - Spline shaft, 66 - Spline bearing. Kudzu 1 Dotsuta 5 Zutsuta Otsu Zuka 7 En 8th 2 [ True 9 Diagram

Claims (1)

[Claims] 1. A base, a first arm supported so as to be able to swing around a first vertical axis on the base, and a second horizontal axis provided at the swinging end of the first arm. a second arm supported so as to be swingable; a first member supported so as to be movable up and down along a third vertical axis provided at the tip of the second arm; a second member configured to be rotatable relative to the first member about a fourth vertical axis parallel to the third vertical axis; and a second member configured to rotate the second member. a first drive means connected to the first member; a second drive means connected to the first member to move the first member up and down along the first vertical axis; An industrial robot characterized in that the robot is equipped with connecting means provided to connect the first member at the upper and lower ends thereof, and a hand attached to the lower end of the second member.