JPS6154557B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a wrist device for a robot.

As is well known, in assembly robots that fit shafts and screw in bolts, the uprightness of shafts and bolts is guaranteed with relatively high accuracy, but positioning accuracy on a plane is There is a drawback that the price is low. In order to compensate for the above-mentioned drawbacks and to allow workpieces such as shafts to be smoothly inserted into recesses even with low positioning accuracy, the robot's hand is equipped with a device that provides compliance on a plane. If the compliance imparting device is built into the hand itself, the gripper device etc. are built into the hand itself, so there is a problem that the hand becomes complicated and heavy, which may result in poor balance with the arm. be.

Therefore, the present invention can be interposed as a unit between the arm and the hand of the robot, and can provide the robot with planar compliance without complicating the structure of the hand itself. The present invention provides a new wrist device which has a simple and lightweight structure.

Examples will be described below based on the drawings.

In the figure, 1 is an arm of the robot, 2 is a hand provided at the end of the arm 1 via a wrist device 3 according to the present invention, and a bar-shaped workpiece W is held between the grip claws 4 of the hand 2. Move the arm 1 appropriately and operate the wrist device 3,
The workpiece W is inserted into the recess 5 as shown in the figure. 6 is a cylinder for driving the opening and closing of the hand.

The wrist device 3 will be described in detail below.

That is, the wrist device 3 includes an arm-side support member 7 integrally fixed to the end of the arm 1, a hand-side support member 8 fixed to the hand 2, one end of which is connected to the arm-side support member 7, and the other end of which is connected to the arm-side support member 7. consists of an intermediate member 9 rotatably connected to the hand side support member 8 in a horizontal plane, and an arm side support member 7
is formed into a fork shape with its tip end divided into upper and lower parts 7a, and a boss portion 9a at one end of the intermediate member 9 is positioned between the two parts 7a, and a pin 11 passing through both parts 7a and 9a. The intermediate member 9 is rotatably connected through the intermediate member 9.

The intermediate member 9 is a member having a substantially right triangular shape in plan view, and the boss portions 9 are provided at two corners other than right angles.
a and another boss portion 9b, and the remaining triangular portion and the vertical plane between both boss portions 9a, 9b are formed into rib-like projecting portions 9c, 9d.

The hand side support member 8 is the boss portion 9b on the other side.
It is a member having a substantially E-shape in side view, with two fork parts 8a and 8b sandwiching the upper and lower sides of the forked part 8.
A, 8b and a boss portion 9b are rotatably connected to the intermediate member 9 by penetrating a pin 12 therethrough. 8
c is a vertical rib.

The lower bifurcated portion 8 of the hand side support member 8
Similar to the projecting portion 9c of the intermediate member 9, b is formed as a substantially triangular projecting portion 8b extending toward the tip of the arm-side support member 7; The overhanging portion 9c and the three overhanging portions 8b, 9 of the two-pronged tip portion (overhanging portion) 7b of the arm-side support member 7
The three members 7, 8, and 9 are connected and arranged so that c and 7b overlap vertically in a plan view, and a lock pin device 13 as described below is provided on the overlapping portion.

That is, the cylinder 15 is mounted on the bracket 14 extending from the base end of the fork-shaped portion of the arm side support member 7.
A lock pin 16 passing through the three members 7, 8, and 9 is connected to the end of the rod 15a of the cylinder 15, and when the cylinder 15 expands and contracts, the lock pin 1
6 is adapted to move up and down by a predetermined stroke, and the lock pin 16 is guided by upper and lower bushes 17 and 18 with respect to the arm-side support member 7 so as to move up and down without rattling in the plane direction. Depending on the vertical position of the lock pin 16, the intermediate member 9 and the hand-side support member 8 can be selectively placed into a free state that allows wobbling in the plane direction, or a mutually fixed state that does not allow movement in the plane direction. It is penetrated so that it can be switched to

That is, the protruding portion 9c of the intermediate member and the protruding portion 8b of the hand-side support member are both provided with lock pin through holes 21 and 22 having the same diameter. Large diameter portions 16a having the same diameter as the diameter are formed above and below at the same interval as the interval between the upper and lower through holes 21 and 22, and the space between the large diameter portions 16a and the tip is formed by the small diameter portion 16.
b, and when the lock pin 16 is in the raised position as shown in FIG. However, while allowing the intermediate member 9 to swing around the pin 11 (compliance movement),
The hand-side support member 8 is allowed to swing around the pin 12 (compliance movement), and when the lock pin 16 is in the lowered position shown in FIG. to fix the intermediate member 9 and the hand-side support member 8 to the arm-side support member 7, and the three members 7,
8 and 9 are integrally connected.

Note that tapers 21a and 22a are formed at the upper edges of the through holes 21 and 22, respectively, so that the intermediate member 9,
After the hand side support member 8 has moved compliantly, if the lock pin 16 is lowered, the large diameter portion 16a
are guided by the tapers 21a and 22a and fit into the through holes 21 and 22, correcting the deviation of the intermediate member 9 and the hand side support member 8, and returning to the original normal connected state. It's summery.

Since the wrist device 3 of this embodiment is configured as described above, the workpiece W is moved into the recess 5 by operating as follows.
It can be inserted inside.

That is, while the arm 1 is moving to the previously taught position of the recess 5, the cylinder 15 is extended and the large diameter portion 16a of the lock pin 16 is fitted into the through holes 21 and 22, as shown in FIG. 2 is integrally connected to the arm 1. As a result, the hand 2 does not wobble during movement, and there is no risk that the gripping state of the workpiece will become poor.

Then, by moving the arm, the work W
as shown by the two-dot chain line in FIG.
After that, the cylinder 15 of the lock pin device 13
is contracted to raise the lock pin 16, and the state shown in FIG. shall be. In this state, the hand 2 can move freely around the two pins 11 and 12, so it can move in any direction within the plane, and when the arm 1 is vertically lowered, the workpiece W, that is, the hand 2 itself, Recess taper 5
The workpiece W is smoothly inserted into the recess 5 while being guided by a.

Once the workpiece W has been inserted into the recess 5 as described above, the grip of the hand 2 is released and the arm 1 is vertically raised. When the hand 2 is completely separated from the workpiece W, the cylinder 15 is extended, and the large diameter portion 16a of the lock pin 16 is guided by the tapers 21a and 22a (taper slope displacement correction) as described above. kicking in the direction)
By fitting into the through holes 21 and 22, the intermediate member 9 and the hand-side support member 8 can be returned to their original connected state, and the hand 2 can be fixed to the arm 1 again.

In the above example, the cylinder 15 was used as the means for vertically driving the lock pin 16, but the cylinder 1
5 may be replaced by a solenoid or an electric motor.

Also, the hand 2 attached to the hand side support member 8
The hand is not limited to the hand having the grip claw 4 as in the above example, but may be any other type of hand such as an electromagnetic adsorption type hand or a chuck type hand.
The shapes of the arm-side support member, hand-side support member, and intermediate member are also not limited to the above examples.

As is clear from the above description, the wrist device of the present invention includes an arm-side support member fixed to the tip of a robot arm, a hand-side support member fixed to the hand, one end of which is attached to the arm-side support member, and the other end of which is attached to the arm-side support member. an intermediate member rotatably connected to the hand-side support member, and the arm-side support member, hand-side support member, and intermediate member each form an overhanging portion where the three members overlap vertically; ,
A lock pin device is provided that vertically passes through the overhang and moves up and down to switch between a connected state in which the three members are fixed together and a free state in which they are mutually movable, so that the wrist device can be attached to the unit between the hand and the arm. It is possible to provide the hand with planar compliance by interposing it as a robot hand, without complicating the structure of the robot hand itself, or increasing the weight and making it unbalanced with the arm.

In addition, since all compliance control can be performed by simply moving one lock pin up and down as described above, the wrist device itself can be made simple and lightweight, and the burden on the control system can be minimized.

Furthermore, the means for controlling compliance on/off is a lock pin that moves up and down, and is not a means that applies a load in a horizontal direction, such as a lever or arm that rotates in a horizontal plane. More accurate and smoother hand mobility can be obtained without interfering with plane movement.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional side view of the tip of the robot arm to which the wrist device according to the present invention is attached, Fig. 2 is a plan view with the cylinder section omitted, and Fig. 3 is a longitudinal sectional view of the main part of the robot arm when the lock pin is in the lowered state (locked state). side view,
FIG. 4 is a sectional view taken along the line -- in FIG. 2. 1... Robot arm, 2... Hand, 3...
Wrist device, 7...Arm side support member, 7b...Tip part (projection part), 8...Hand side support member,
8b... Bifurcated part (overhanging part), 9... Intermediate member, 9a, 9b... Boss part, 9c... Overhanging part, 11, 12... Pin, 13... Lock pin device, 16... Lock pin, 21 , 22...through hole.

Claims (1)

[Claims] 1 A wrist device that is interposed between an arm and a hand of a robot to give plane compliance to the hand, the arm-side support member being fixed to the tip of the arm, and the hand-side support being fixed to the hand. member, and one end is connected to the arm side support member and the other end is rotatably connected within one plane via a pin perpendicular to the hand side support member, so that the hand side support member is connected to the arm side support member. and an intermediate member connected movably in any direction within one plane, and the intermediate member has two boss portions at both ends through which the vertical pin passes through, and a rib-shaped rib connecting the boss portions. The hand-side support member, the arm-side support member, and the intermediate member each include an overhang portion of the intermediate member, an overhang portion formed on the arm-side support member, and the hand-side support member. The overhanging parts formed in the above three members are connected in a vertically overlapping state, and the three members are vertically moved through the through holes drilled in the overhanging parts in the shape of a skewer, so that the three members can be moved individually. A wrist device for a robot, characterized in that it is provided with a lock pin device that switches between a state in which three members cannot be fixedly connected together and a free state in which the three members are mutually movable.