JPS58128507A - Hydraulic type actuator - Google Patents

Abstract

PURPOSE:To normalize the control of automatic working fluid supply to a hydraulic motor by a method wherein a change-over valve is change-overed by a cam body which is screwed as freely movable with a screw rod which is rotated synchronizing with a worm shaft located on a casing outside part. CONSTITUTION:The rotating force of a worm shaft 4 is transferred, via a drive mechanism 21, to a screw rod 19 which is arranged as rotatable on a outside of a casing 6, the screw rod 19 is rotated synchronized with a worm shaft 4. A nut-shape cam body 26 is screwed as freely movable with the screw rod 19 at the condition which its rotation is locked by a guide rod 27, a pilot valve 17 for controlling of the hydraulic motor is change-overed by the cam body 26.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic actuator used for opening and closing valves, etc.

Actuators used for opening and closing valves include, for example, a worm wheel for driving an output shaft, a worm shaft having a worm that meshes with the worm wheel, and an electric motor that rotationally drives the worm shaft in a casing. It is common that the inner chamber is housed in a unit. In the conventional type, the worm shaft is supported so as to be elastically displaceable also in the axial direction, and when the valve body connected to the output shaft reaches a closed position Ikt or a maximum open position, a large amount of force is applied to the output shaft. The displacement of the worm shaft in the axial direction when a load is applied is utilized to switch a limit switch or the like for controlling the electric motor. However, with such a structure, the curved limit switch must be disposed within the casing, so it is difficult to adjust the mounting position of the limit switch.

The present invention was made with attention to such circumstances, and
In addition to converting the electric motor system to the hydraulic motor system, we also provide a new actuator that appropriately controls the supply of hydraulic fluid to the hydraulic motor. Instead of the conventional method in which the switching valve is switched by the elastic displacement of 1 so that the switching valve can be switched
This provides a hydraulic actuator that is strained to ensure proper operation.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

A worm wheel 2 for driving the output shaft 1, a worm shaft 4 having a worm 8 meshing with the worm wheel 2, and a hydraulic motor 5 for rotationally driving the worm shaft 4 are housed in a casing 6. There is.

The output shaft 1 is a shaft that projects outward from the lower surface of the casing 6, and its base end is attached to the casing 6 with a bearing 7.
It is rotatably supported integrally with a wheel shaft 8 which is rotatably supported via a shaft 7. The worm wheel 2 is fitted around the outer periphery of the wheel shaft 8 so that it can rotate integrally therewith. On the other hand, the worm shaft 4 is rotatably supported by the casing 6 with its axis perpendicular to the axis of the output shaft 1 via a bearing 9.9 disposed within the casing 6. Note that one end of the worm shaft 4 projects outside the casing 6, and forms a prismatic engagement portion 4a for connecting a rotary lever for manual operation to the one end. Reference numeral 11 denotes a cap for protecting the engaging portion, which is detachably attached to the casing 6. The other end of the worm shaft 4 is connected to the rotation output section 5a of the hydraulic motor 5. The hydraulic motor 5 is of a type in which a housing 5C rotates around the axis of a support shaft 6b, and the support shaft 5bftii
When the casing 6#ζ is fixed, the rotation output portion 5a is integrally formed on the end face of the housing 5C. FIG. 4 shows a hydraulic circuit for supplying hydraulic fluid to the hydraulic motor 5, and reference numeral 12 in the figure shows the hydraulic fluid supplied to the opening-side working wave inlet 13I. 10,000 working fluid inlet 5d#ζ opening pipe line for guiding;
Reference numeral 14 denotes a closing side pipe line for guiding the hydraulic fluid supplied to the closing side hydraulic fluid inlet 15 to the other hydraulic fluid inlet 5e of the hydraulic motor 5. Further, 16 is the opening side pipe line 12.
A limit valve 17 inserted in the middle is a pilot valve for controlling the closing of the air limit valve 16. Each of the hydraulic fluid inlets 18.15 is provided in a manifold 18 that covers the opening Iζ of the casing 6, and the starting end side of each of the pipe lines 12.14 is formed inside the manifold 18. .

In the actuator thus constructed, a threaded rod 19 is rotatably disposed outside the casing 6, and the rotational force of the worm shaft 4 is transmitted to the threaded rod 19 via the transmission mechanism 21. The threaded rod 19 is rotated in synchronization with the worm shaft 4Iζ. The transmission mechanism 21 includes a worm 22 fixed to the outer part of the worm shaft 4, a worm wheel 28 that is rotatably supported by the casing 6t and meshes with the worm 22, and a worm wheel 28 that is provided through the manifold 18. and a connecting rod 24 that connects the threaded rod 19 to one end of the threaded rod 19. ing. The threaded rod 19 and the nut-shaped cam body 26 are screwed together so that they can move forward and backward with the guide rod 27 inhibiting rotation, and the pilot valve 17, which is a switching valve for controlling the hydraulic motor, is screwed together with the cam body 26. I am trying to switch between. Note that 27 is a cover for protecting the threaded rod 19, cam body 26, pilot hearth 1f, etc. arranged outside the casing 6, and the cover 27 is removably attached to the casing 6I. There is.

Next, the operation of this actuator will be explained.

First, when hydraulic fluid is supplied to the opening-side hydraulic fluid introduction port 18 from a hydraulic pressure source (not shown), the housing 5C of the hydraulic motor 6 rotates together with the worm shaft 4. Therefore, the worm wheel 2 that meshes with the worm 8Iζ of the worm shaft 4 is driven, and the output shaft 1 rotates in the forward direction at a slow speed.

As a result, for example, a valve body (not shown) of a valve (not shown) connected to the output shaft I through a mechanism for converting rotational motion to a linear motion number ζ (a type in which a valve stem supporting the valve body is screwed into a valve body) When the valve stem is directly connected to the output shaft II, the valve moves away from the valve seat in the opening direction E.

Further, in this case, since the screw 19 rotates in synchronization with the worm shaft 4, the cam body % screwed onto the threaded rod 191 moves in the direction of the arrow X in response to the movement of the valve body. Then, when the valve body reaches the maximum open position, the cam body 26 moves toward the operator 171 of the pilot valve 17.
Press h EEI, and the pilot valve 17 switches from the first position (1) to the second position (1) shown in the fourth figure. Then, a part of the working fluid in the opening side pipe line 12 is supplied to one pilot chamber i of the limit valve 16 via the pilot valve 17, and the limit valve 16 changes from the open position 1t(A) to the closed position ( B) tz is switched to cut off the opening side conduit 12. As a result, the supply of hydraulic fluid to the hydraulic motor 5 is cut off, and the hydraulic motor 5 is stopped.

In this state, in reverse Cζ, a part of the hydraulic fluid for the closing side operation is supplied to the other pilot chamber of the limit valve 16 through the pilot pipe A, and the IJE button valve 16 is opened from the closed position l1l (B). Switch to position (A). As a result, the hydraulic motor 5 rotates in the opposite direction and the valve body moves in the closing direction.

In this way, in the actuator of the present invention, by selectively connecting the opening-side hydraulic fluid inlet 18 or the closing-side hydraulic fluid inlet 15 to the hydraulic pressure source, it is possible to connect the hydraulic pressure source from the output shaft 1 in the forward and reverse hook directions. However, since the actuator of the present invention is of a hydraulic type, it is also possible to drive the rotation of the worm or worm wheel with high torque, which engages the output shaft. The basic feature is that the load range can be widened.

Since the pilot valve 17 for controlling the supply of hydraulic fluid to the hydraulic motor 5 is switched, there is no need to support the worm shaft 4 so that it can be elastically displaced in the axial direction. In other words, when switching a conventional electric limit switch, a certain amount of operation stroke is required, so the worm shaft must be elastically displaced in the axial direction, making the operation unstable during normal operation. However, in the heat of the present invention, the worm shaft can be moved in the axial direction Iζ.
There is no need to enable elastic displacement. Therefore, the operation of the output shaft 1 may become unstable due to fluctuation in the axial direction of the worm shaft 4, and the structure of the support portion of the worm shaft 4 and the connection portion between the worm shaft 4 and the hydraulic motor 5 may be complicated. Inconveniences such as increase in size can be eliminated. Further, since the pilot valve 17 can be disposed outside the casing 6, there is an advantage that the mounting position of the valve 17 can be easily adjusted.

In the above embodiment, the present invention was applied to an actuator equipped with only a pilot valve for controlling the open position of a valve body. For example, a pilot valve for controlling the open position of a valve body An actuator valve equipped with a pilot valve for controlling the closing position or closing force of the valve body can be similarly applied.

That is, in this case, a pair of cam bodies may be screwed onto the threaded rod.

Furthermore, the basic configuration of the actuator is of course not limited to that of the illustrated embodiment; for example, a mechanism that converts the rotation of the worm wheel into forward and backward movement of the output shaft may also be provided inside the casing. There may be.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a partially cutaway plan view, FIG. 2 is a partially cutaway front view, FIG. 8 is a partially cutaway side view, and FIG. 4 is a circuit diagram. be. 1... Output shaft 2... Worm wheel 8...
Worm 4... Worm shaft 5... Hydraulic motor 6... Casing 17... Switching valve (pilot valve) 19... Threaded rod 26... Cam body agent Patent attorney Hiroshi Akazawa

Claims (1)

[Claims] A worm shaft having a worm wheel for driving an output shaft, a worm that meshes with the worm wheel, a casing that houses a hydraulic motor that rotationally drives the worm shaft, and a threaded rod disposed outside the casing. A transmission mechanism that rotates this threaded rod in synchronization with the worm shaft, a cam body screwed onto the threaded rod so that it can move forward and backward, and a hydraulic motor that is switched by being biased by this cam body. A hydraulic actuator characterized by being provided with a switching valve for controlling liquid supply.