JPS58221004A - Rotational drive mechanism - Google Patents

Abstract

PURPOSE:To enable a smooth rotational drive to be achieved, by eliminating rotational inertia through the angle of rotation made variable within a predetermined range. CONSTITUTION:When the driving piston is operated at its maximum stroke, then in the vicinity of the end of the movement of the drivin piston, one of the valves 62, 62a attached to the driving piston and located in the exhaust side of the cylinder space abuts against the end wall of the main cylinder hole thereby to close the intake-and-exhaust port 11 or 11a. As a result, the subsequently exhausted fluid is only allowed to be discharged through the throttled passage 12 or 12a, whereby braking force is exerted on the driving piston. Inertia is thus decreased toward the point the rotation is stopped, so that the rotational drive mechanism is enabled to make a smooth rotational motion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary drive device using fluid pressure as a drive source, particularly suitable for use as a drive source for industrial robots.

A reciprocating rotary drive that has the same function as human joints is essential for robots. Among the mechanisms that perform such rotational drive, there are those that use fluid pressure, and those that combine a swinging vane motor and a rack and pinion, but in each case, two or more types of swinging It was difficult to obtain the angle reliably and accurately. In other words, in the conventional technology in which a pinion and a rack are used to operate the reciprocating motion of the rack using a pressure fluid as a driving source, and the pinion is rotated and oscillated via the rack, a rotation oscillation of a predetermined second or more position is obtained. However, the method of stopping the rack or pinion with a stroke has the disadvantage that the mechanism is complicated and the stopping position is not accurate. Furthermore, it is difficult to obtain inertia in order to stop a moving object.

The purpose of the present invention is to provide a rotary drive device using a rack and pinion, in which the rotation angle (swing angle) can be changed within a predetermined range, and the inertia caused by rotation can be eliminated to enable smooth rotational drive. be.

The present invention provides a rotary drive device in which a rack is attached to a drive piston movably provided in a main cylinder hole, and the rack is linearly reciprocated by the drive piston to rotate a pinion meshing with the rack, at least at one end of the cylinder. An auxiliary cylinder hole is provided on the side that communicates with the cylinder hole, and a control piston is movable into the auxiliary cylinder hole. The opening end of the supply/discharge port to the hole is arranged at 4PO of the piston rod, and the drive piston is engaged with the end of the piston rod to prevent communication between the main cylinder hole and the supply/discharge port. A valve body is mounted to be movable relative to the drive piston, and the control piston and piston rod are moved toward the drive piston to change the stroke of the drive piston to change the rotation angle of the pinion and cooperate with the valve body. to limit fluid discharge from the main cylinder bore and apply braking to the drive piston.

Embodiments of the present invention will be described below with reference to the drawings.

In the figure, an embodiment of a rotary drive device according to the invention is shown. The rotary drive device 1 of this embodiment is constructed by integrally incorporating a plurality of control cylinders 6.4.3α, 4a on both sides of the drive cylinder 20 and a pinion 5 rotated by the drive cylinders into the main body. . Note that since the control cylinders 6 and 4 and the control cylinders 6a and 4α, respectively, have the same structure and function except for the difference in their arrangement positions, only one of them, 3 and 4, will be explained.

The drive cylinder 2 has a main cylinder hole 21 formed approximately in the center of the main body 10, and a cylindrical drive piston 22 movably disposed within the cylinder hole 21. A rack 26 is formed on the drive piston 22, and the rack 26
A pinion 5 rotatably supported by the main body is engaged with the pinion 5. An axial through hole 24 is formed in the drive piston 22, and a rod 26, which is longer than the drive piston, is inserted through the through hole 24 so as to be movable relative to the drive piston. Valve bodies 27 and 27α are fixed to both ends of the rod 26, which engage with the ends of a piston rod of a control piston, which will be described later, to close a supply/discharge port to the main cylinder hole.

The first control cylinder 3 is formed in the main body 10 close to one end of the main cylinder hole (the right end in the figure) and communicates with the main cylinder hole through the annular hole 2. a ring movably disposed within 61;
and a first control piston 36 . A tubular piston rod (64) fixed to the control piston 36 extends through the annular hole 62 so that when the control piston 66 is at the right end position as shown in the figure, the end surface of the piston rod 64 is approximately flush with the right end surface of the main cylinder hole 21. It is designed to be -.

The second control cylinder 4 has a second auxiliary cylinder hole 41 formed in the main body 10 adjacent to one end (the right end in the figure) of the main cylinder hole and communicating with the first auxiliary cylinder hole through an annular hole 42. and an annular second control piston 43 movably disposed within the auxiliary cylinder bore 41. A tubular piston rod 44 fixed to the control piston 46 extends through the annular hole 42 so that when the control piston 43 is at the right end position as shown in the figure, the end surface of the piston rod 44 is separated from the right end surface of the first auxiliary cylinder hole 61. It's starting to get tough.

The main body 10 has a pair of supply/discharge ports 11.11α that open at both ends of the main cylinder hole inside the annular piston, and the supply/discharge ports 11 and 11a are connected to the main cylinder hole through variable throttles 6 and 6a, respectively. A pair of throttle passages 12 and 12α are formed which communicate with each other. Supply/discharge port 11
and 11a are connected to a fluid pressure source via one switching valve 7, and by alternately switching the switching valve, fluid pressure is alternately supplied and discharged, thereby reciprocating the drive piston 26. .

The body 10 further includes first and second control ports 15.15a and 16.1 communicating with the first and second auxiliary cylinder holes.
6a are formed, each of which has a separate control valve 8.8
α and 9.9a, respectively.

Next, the operation of the rotary drive device of this embodiment will be explained.

If it is desired to operate the drive piston at the maximum stroke to maximize the rotation angle, only the switching valve 7 is operated without operating either of the control valves 8.8a and 9.9α. In this way, fluid pressure is alternately supplied to chambers A and B on both sides of the drive piston 2 through the supply/discharge port 11.11α, the drive piston reciprocates, and the pinion also reciprocates at the maximum angle. Near the end of the drive piston's movement, the valve body 62 or 62α (projected in the direction of movement due to the folding of the drive piston) in the chamber that is attached to the drive piston and serves as the exhaust side comes into contact with the end wall of the main cylinder hole. In order to contact and close the supply/discharge port 11 or 11a,
The fluid that is then discharged is discharged only through the throttle passage 12 or 12α, and the drive piston is braked to reduce its inertia when it stops rotating.

Next, when it is desired to reduce the rotation angle of the pinion by one step, the control valve 9 or 9a for the second control cylinder is operated to supply fluid pressure to the chamber E or F to the supply box 1 and the second control piston 6.
and 4 or 6a and 4a are moved toward the drive piston by the stroke of the second control piston.

For example, if the control valve 9a is now operated to supply fluid pressure to the chamber F of the second control cylinder 4α, the first and second control pistons 6a, 4a will move toward the drive cylinder side by the stroke of the second control piston. The piston rod of the first control piston 6a protrudes into the main cylinder chamber by that amount, thereby restricting the movement of the drive piston. Therefore, the stroke of the drive piston 22 becomes smaller by that amount (one second control piston), and the rotation angle of the hyonion also becomes smaller proportionally.

In this case as well, the drive piston moves to the left and moves into chamber B.
The valve body 27a protruding from 11411 is the piston rod 1-
When it abuts against and engages with the tip of the piston, the communication between the chamber B and the supply/discharge port 11α is cut off, and the fluid in the chamber B is discharged only through the throttle passage 12 (Z), so the drive piston is not braked. is applied, and the inertial force is reduced until it comes to a stop.

Hereinafter, if necessary, in the same manner as described above, both the second control cylinders 4 and 4α, one of the second control cylinders (for example, 4゛) and the other of the first control cylinder (for example, the rotor a)
, or the first control cylinder can be selectively operated to limit the stroke of the drive piston and change the rotation angle of the pinion.

Note that it is possible to provide two or more control cylinders in series on one side θ) of the drive cylinder, and in that case, it is necessary to increase the stroke in the order closer to the drive cylinder. The strokes of the left and right control pistons of the drive cylinder do not necessarily have to be the same;
It can be selected arbitrarily as needed.

Furthermore, since the movement of the drive piston is regulated by the control piston, if fluids of the same pressure are used, the pressure receiving area of the control piston must be larger than that of the drive piston.

Furthermore, although the above embodiment describes the case where the rotation angle is changed, the pressure receiving area of the control piston (or working fluid pressure)
is very small compared to that of the driving piston, and the driving piston pushes the control piston.1. If it can be returned, the stroke of the drive piston can be kept constant and the braking start position of the drive piston can be selectively changed.

As described above, in the rotary drive mechanism of the present invention, since the rotational drive mechanism of the present invention is reliably stopped by the mechanical stopping means, the rotation angle can be reliably controlled, and at the same time, the inertia can be reduced by applying braking at the time of stopping.

[Brief explanation of the drawing]

The figure is a sectional view of an embodiment of a rotational drive device according to the present invention. 1: Rotation drive device 2: Drive cylinder 26: Drive piston 3.4.3α, 4α: Control piston lobe 6.46: Control piston lobe 4.44: Piston rod 9 5: Binion 62: Valve body

Claims (1)

[Scope of Claims] 1. A rotary drive device in which a rack is provided on a drive piston movably provided in a main cylinder hole, and the rack is linearly reciprocated by the drive piston to rotate a pinion meshing with the rack, an auxiliary cylinder hole is provided in at least one end of the cylinder that communicates with the cylinder hole, a control piston is movably provided in the auxiliary cylinder, and a piston rod of the control piston is formed into a tubular shape so that it can protrude into the main cylinder hole; The opening end of the supply/discharge port to the main cylinder hole is arranged inside the piston rod, and the drive piston is engaged with the end of the piston rod to prevent communication between the main cylinder hole and the supply/discharge port. A rotary drive device, characterized in that a valve body is mounted so as to be movable relative to the drive piston. 2. A rotary drive device characterized in that the auxiliary cylinder holes are provided on both sides of the main cylinder hole, and each of the auxiliary cylinder holes is provided with a control piston. 3. A separate auxiliary cylinder hole is further provided adjacent to the auxiliary cylinder hole, and a separate control piston that presses an adjacent control piston is movably provided in the separate auxiliary cylinder hole. The rotary drive device according to Range 1 or 2.