JPS5890483A - Driving device - 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 The present invention relates to a drive device that linearly interchanges linear motion and rotational motion.

Conventionally, this type of device has been used in a variety of situations, but a drive device used for the joints of articulated robots used, for example, in arc welding work and assembly work will be described. The drive devices used in these joints are particularly required to be lightweight and compact, and to have linear conversion between linear motion and rotational motion. be.

That is, in the case shown in FIG. 1, an axle (b) such as a sprocket or a pulley is attached to a pivot (α) that rotates integrally with one of a pair of rotatably connected nodes. A flexible member (c) such as a chain or belt is hung around the axle (b), and both ends of the flexible member (1) are tied to the cylinder fd), and the straight line of both cylinders (d) is The movement is an axle (6
), there is one that converts the motion into rotational motion via a bending member (c). Furthermore, the one shown in Fig. 2 uses a gear (g) as an axle mounted on a pivot (α), and a rack (A) is meshed with the gear (1) to control the linear motion of the cylinder (d). This converts it into rotational motion.

However, the former requires two sets of cylinders, resulting in a large structure and complicated piping for the cylinders, making it expensive. Furthermore, the latter requires an offset between the gear (1) and the rack (c), making it difficult to downsize and also expensive.

The present invention eliminates such drawbacks and provides a drive device that is inexpensive, small, lightweight, and linear in mutual conversion between linear motion and rotational motion, in which a pair of pinion gears are meshed with a rotatable internal gear. Also, an idler is meshed with one of the pinion gears, and a linearly movable rack is meshed with the idler and the other pinion, so that rotary motion and linear motion can be mutually converted. It is something to do.

An embodiment in which the present invention is applied to a joint part of an articulated robot will be described below with reference to FIGS.

FIG. 3 is an external view of an articulated robot using the drive device according to the present invention, particularly in which the joints are exposed.

The articulated robot has a post (2) erected on a frame (1), and a first arm (3) and a first arm (3) on the post (2).
3), the second arm (4), the first joint (5),
The second arm (4) is rotatably connected at the second joint (6), and a tool or gripper can be attached to the tip of the second arm (4). The first joint (5) and the second joint (6) are provided with a joint drive device (7) having the same structure, and by appropriately driving the drive device (7), the first arm (3)
, which causes the second arm (4) to make a desired movement.

Next, in FIGS. 4 to 6, the drive device (force) provided at the first joint will be explained in detail.

A pair of brackets (8) (9) on the top end of the post (2)
are fixed in parallel, and a mounting hole αI0υ having an axis parallel to the tip of the bracket l-(8) (9) is concentrically bored. A disk-shaped mount Q3) Q4) having a protruding center portion (+21 formed therein) is fitted into the mount hole αωαυ so that the shaft portions Oz face each other. On the other hand, the base of the first arm (3) (the end on the side of the first joint (5)) is parallel to the bracket l-(8) (9), and the bracket (8)
(9) A pair of arm plates aue that fit in between are projected, and a coupling hole aηα concentric with the mounting hole 00)0υ is provided at the tip of the arm plate 051Q6).
Drill a uniform. The post (2) and the first arm (3) are made rotatable by fitting the bearing Q Yu to the shaft portion Q21 and further fitting the arm plate (15) Q6) to the bearing α■09). Join. Arm plate α5) (161
Inside the coupling hole (1η0gl) and the internal gear (
a) Install (21) and both internal gears (2υ(21)
), the pinion (22) (23) and both internal gears (20 (21)) are meshed with each other, and the pinion (23) and idler (C11) are meshed with each other. and are rotatably attached to the shafts (25) and (26) c2η. The shafts (25), (26), and (27) are connected to the mount (13).
) (14) and is fixed to the mount (131Q4) via the eccentric sleeve (28) at both shaft ends of each shaft. By appropriately rotating this eccentric sleeve example, the pinion (2Z (23) , the center position of the idler (24) can be changed, and these gears (22 (2)
By adjusting the center position of 31 (2(a)), the internal gear (201(2υ) and the rack (29) (3
0), pinion (221 (231), idler (24
) are attached to the optimal interlocking state.

A cylinder (a) is provided on the post (2) with a rod 0η protruding toward the joint center side, and a connector (to) is fixed to the tip of the rod 0υ. A pair of link plates @ (to) are rotatably attached to the connector (to) by a pivot (to) whose axis is parallel to the axis of the pinion, and the thin neck portions ( Insert the link plate @ (to) and the rack (29) (to) between the neck part (to), respectively.
It is pivotally connected via rack shafts (b) and (to).

In addition, a pair of racks (29) 00) are equipped with internal gears (2
0) (21), and the pinion (22) and the idler C are inserted perpendicularly to the axis of the internal gear.
24). Then, Luck (Ha) (30
) is provided with an escape α on the facing surface of the connector (to), and the rack (2
9) (301 can be rotated by the required angle in the direction of separation, and a compression spring (G) is provided between the racks (29) and (30) to bias the racks (29) (3) in the direction of separation. Then, rack @ (to) and pinion (22), idler (2
4) Apply the required meshing force between them.

Next, the operation of the drive device having the above configuration will be explained.

In Fig. 4, when the cylinder (2) is extended, both racks (mark 2) rise and the pinion @ is moved counterclockwise.
The pinions (23) are also rotated counterclockwise via the idlers (24). Pinion (221 (23)
As the internal gear (A) rotates, the internal gear (A) CD rotates counterclockwise, and the first arm (3) to which the internal gear (2I (21) is fixed) also rotates counterclockwise. The amount of extension (to) and the amount of rotation of the first arm (3) are clearly directly proportional.

Needless to say, when rotating the first arm (3) clockwise, the cylinder (to) may be shortened.

Next, in the above configuration, pinion (22) and (2
3) in the same direction, one pinion (23
) and the rack (to), there is an idler (24) interposed between the pinion @ and the rack (29), and the idler (29).
24) and the rack (7) are not the same, so when forming the teeth of the rack (29) and the rack (24), it is necessary to The phase of the teeth is shifted. It is not impossible to accurately obtain this amount of deviation by machining, but it requires more precision than necessary, which increases manufacturing costs and is uneconomical. It is possible that the phases of the teeth of both racks @ (7) may be shifted due to installation errors of 221 (23, idler (24), etc.). Absorbs deviations caused by processing errors, installation errors, etc. mentioned above with respect to the appropriate amount of rubbing.

That is, rack (2gl and pinion (2z1) rack (7
) and idler f2 chrysanthemum engagement is incomplete, the cylinder (goods) to rank (291 (to)
The force is transmitted to the link plate (b) (
A moment acts on (to), and the link plate @ (to) rotates. When the link plate @ (to) rotates, the rack (c) (to) shifts in the longitudinal direction, and the state of engagement between the two is corrected and perfected. Also, when the amount of backlash on the rack side and the rack (to) side is different due to the presence of an idler (024), and the rack @ (to) moves back and forth,
The engagement changes on the outward and return journeys, but this change is also absorbed by the rotation of the link plate and the displacement of the rack in the longitudinal direction. Therefore, the loads applied to both racks @ (7) are always equal, and it is possible to transmit twice the load that can be transmitted by one rack/pinion.

In the above embodiment, both racks are made to be able to shift relative to each other using link plates, but various other systems having the same function have been prepared. Teeth are formed on the surface facing the root of the rack,
One example is one in which a gear that meshes with both teeth simultaneously is interposed between both racks, and this gear is rotatably attached to a cylinder. Furthermore, the device that causes the rack to move linearly is not limited to a cylinder, but may also be a screw. Furthermore, by accurately machining the rack and pinion, etc., it is possible to securely attach the rack to the cylinder without using a link plate, etc. Various changes can be made without departing from the gist of the present invention. Needless to say.

As described above, the drive device according to the present invention requires only 1/2 the number of modules and one actuator such as a cylinder for the same load capacity as the conventional one, and furthermore, it is not necessary to offset the rack with respect to the center of rotation. It is small and lightweight because there is no Of course, the amount of movement of the rack and the amount of rotation of the internal gear are in an exact proportional relationship. Therefore, if the present invention is applied to the joints of a robot, the structure of the first arm supporting the second joint will be light, and the load borne by the first joint will be reduced, and the second joint and the first arm will have a lighter structure. Due to the synergistic effect of reducing the weight of
Capacity can be reduced and manufacturing costs can be reduced.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams of conventional drive devices, respectively.
The figure is an external view of an articulated robot equipped with an embodiment of the present invention.
4 and 5 show details of an embodiment of the present invention, in which FIG. 4 is a plan sectional view, FIG. 5 is a side sectional view, and FIG. 6 is a view taken along arrow A in FIG. (3) is the first arm, (4) is the second arm, Kan (21)
is internal gear, (22+(c) is pinion, 124
indicates an idler, (to) indicates a rack, and (2) indicates a cylinder. Figure 1d Figure 2

Claims (1)

[Claims] 1) A pair of pinion gears are engaged with a rotatable internal gear, an idler is engaged with one of the pinion gears, and a linearly movable rack is engaged with the idler and the other pinion, so that rotational motion and linear motion are A drive device characterized in that it is configured to mutually convert motions of motions.