SU1015134A1 - Intermittent rotation pneumatic drive - Google Patents

Description

The invention relates to the control of various mechanisms in which a reverse rotation of the output shaft is required, for example, pipe stop valves.

A pneumatic drive of intermittent rotational movement is known, which contains air motors with a control input and a working chamber, interacting by means of a ratchet mechanism with a gear wheel fixed on the output shaft, spool pneumatic distributors with an end chamber and two annular grooves, one of which is connected to a control input of a pneumatic actuator and the other with the atmosphere, safety valves with output and limit switches installed with the possibility of interaction with the output m shaft 1.

The disadvantages of the known drive are the complexity of the design and lack of reliability due to the presence of an additional mechanism for changing the spring torque on the output shaft.

The purpose of the invention is to increase reliability and simplify the design.

The goal is achieved by the fact that the pneumatic drive of intermittent rotary motion, which contains air motors with a control input and a working chamber, interacting through a ratchet mechanism with a gear wheel rigidly mounted on the output shaft, spool pneumatic distributors with an end chamber and two annular grooves, one of which is connected pneumatical actuator and another with atmospheric, safety valves with outlet and end switches, installed with Stu reacting with the output shaft, wherein the end member of the spool valves of each chamber in communication with the bore, communicating with the atmosphere via an additional channel formed with the throttle, and the output of the safety valve associated with the end chamber via a limit switch.

FIG. 1 is a schematic diagram of the drive; in fig. 2 - drive schedule.

The pneumatic drive of intermittent rotary motion contains pneumatic motors 1 and 2, each of which includes a control input 3 and a working chamber 4, interacting by means of the ratchet mechanism 5 with a gear wheel 6 fixed on the output shaft 7, spool valves 8 and 9, each of which - equipped with an end chamber 10, a spool 11 with an annular groove 12 formed thereon, communicated with a control input 3, an annular

groove 13, communicated with the atmosphere, and the channel 14 with the throttle 15. In addition, the actuator contains safety valves 16 and 17, made double-seat,

one outlet 18 of which is in communication with the atmosphere, and the other outlet 19 through an annular switch 20 with a locking element 21 with an end chamber 10 pneumatic distributors 8 and 9.

The pneumatic drive of intermittent rotational motion operates as follows.

The safety valve 16 is adjusted to operate at a pressure in the working chamber 4, the air motor 1, which provides the required torque when the valve (not shown) reaches the “Open. The safety valve 17 is adjusted to operate at a pressure in the working chamber 4 of the pneumatic engine 2, which seals the valve shut-off member at the “Closed.

The limit switches 20 are mounted so that their shut-off element 21 is released under the influence of a kinetic connection with the output shaft 7 before the valve has reached one of the extreme positions.

When a control signal is applied to the pneumatic valve 8 and further to the control input 3 of the pneumatic engine 1, the last

Through the ratchet mechanism 5, the gear wheel 6 is coupled. The valve valve associated with the output shaft 7 will move in the direction of the "Open." Position.

If a torque exceeding the torque determined by the presetting of the safety valve 16 is required to disrupt the reinforcement, the latter triggers with the output 18 overlapping. The working medium through the output 19 enters the limit switch 20, which does not operate as it is blocked by the locking element 21. This ensures a further increase in the pressure of the working medium in the working chamber 4 of the air motor 1 and an increase in the torque on the output shaft 7.

After the valve is removed from the extreme position, the torque required to move it, as a rule, sharply decreases. As the valve body approaches the "Open" position, the locking element 21 of the limit switch 20 is released.

When position is reached, the working medium from the outlet 19 of the safety valve 16 is opened by the shut-off valve of the valve through the limit switch 20 enters the end chamber 10 of the pneumatic valve 8, causes the valve to move and to the right (according to the drawing), turning off the control signal and the pneumatic motor 1.

When the control signal is removed to the valve 8, the spool 11 of the latter is reset. Channel 14 with throttle 15 serves to prevent the spool 11 from operating falsely when the working medium enters the annular groove of the end chamber 10 and to reliably actuate spool 11 when the signal from the safety valve 16 is low;

Similarly, the pneumatic motor 2 is turned on and off when the valve has reached the position of the valve closed.

The ordinate axis (Fig. 2) shows the number of revolutions n of the output shaft 7, which is required to move the valve body from the position "Open to position" Closed. Point a corresponds to the position of the open valve.

At point b, the release of the stop valve 21 of the air motor switch 20 is released.

At point b, the locking element 21 of the switch 2Q is released. air motor 2.

Point g corresponds to the position "Closed valve organ.

FIG. 2 denotes: maximum torque developed by the drive; the torque required to seal the valve body when it is closed; Mjjp is the torque required to fix the valve body in the "Open" position; The estimated torque required to break the valve in the closed position.

The broken line of line 1 (see fig. 2) is the change in the maximum torque of the actuator when closing the valve body; Line 2 is the change in the maximum torque of the actuator when the valve is opened; Line 3 is broken - the maximum torque is changed at the output shaft of the drive when the valve is opened.

In addition, in FIG. 2 marked: R.- pressure at the inlet of the pneumatic distributor 8; РВЫХ- pressure at the outlet of the pneumatic distributor 8; P „- pressure at the outlet of the safety valve 16; P - pressure in the end chamber 1U

The excess of the set torque value fully meets the requirements of the valve operation and is achieved by a simple and affordable means, which greatly simplifies the design of the actuator.

Claims (2)

57) PNEUMATIC DRIVE OF INTERMEDIATE ROTARY MOTION, containing pneumatic motors with a control input and a working chamber, interacting by means of a ratchet mechanism with a gear wheel rigidly mounted on the output shaft, zolotnik pneumatic distributors with a face chamber and two annular grooves connected to one of the inlets with one of the inlets of which are connected with an input from one of the drives and the other with the atmosphere, safety valves with output and limit switches installed with the possibility of interaction with the output shaft, o characterized in that, in order to increase reliability and simplify the design, the end chamber of each spool valve is connected with a groove communicated with the atmosphere through an additional channel with a throttle, and the safety valve output is connected to the end chamber through an end switch. / 2 Fig. one