JPS5819884B2 - Hydraulic rotary actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic rotary actuator that is used with its axis of rotation directed particularly in the vertical direction.

Note that the above-mentioned vertical direction should not be interpreted narrowly as being vertical.

It doesn't have to be horizontal. Now, a rotary actuator has a base part and an operating part that rotates with respect to the base part.

These pressure seals between the base part and the working part are constructed with a very small gap so that a lubricating film can only form.

If this gap is too small, a lubricating film may not be formed between the base portion and the operating portion, resulting in an unrotatable state.

By the way, in a rotary actuator, the base portion and the actuating portion are opposed to each other at both ends of the pressure chamber when viewed in the direction of the rotation axis, and sealed to prevent a large amount of pressurized fluid from leaking.

Since the axis of rotation of this seal part is facing in the vertical direction, if the seal part that is higher up is called the upper seal and the one that is lower is the lower seal, then the upper seal or the lower seal of the base will be formed. The weight of the actuating part will be applied to one of the parts.

For example, if the gap is applied to the lower seal, the gap between the lower seal and the upper seal becomes smaller, and the gap between the upper seal becomes larger.

If this state is left as is, the flow resistance of the liquid in the upper seal part is smaller than that in the lower seal part, so more pressurized fluid will flow into the upper seal part.

Therefore, the surface constituting the lower seal of the base must bear not only the weight of the actuating part but also the force exerted by the pressurized fluid on the upper seal.

As a result, the formation of a lubricating film on the lower seal deteriorates, and eventually the seal becomes unable to rotate as described above.

Therefore, the present inventors first proposed a device in which a spring member is provided that acts in a direction to displace the actuating portion upward, and the reaction force of this spring member is received by the base portion.

(Japanese Patent Application No. 51-92330) However, if a helical spring is used as this spring member, it is necessary to form both end surfaces of the helical spring perpendicular to the center of the helical spring. The resulting force acts on the actuating part as an unbalanced load, the distance between the base part and the actuating part becomes uneven, a good lubricating film is not formed, and even if a helical spring is inserted, no great effect can be expected. I found out something.

It has also been found that the helical spring itself has a large axial length, so it is not possible to make the whole spring compact.

The present invention has been made in view of the above points, and an object thereof is to construct a hydraulic rotary actuator that can form a good lubricating film and can be made compact as a whole. It is in.

That is, in the present invention, an annular undulating spring having a plurality of waves at equal intervals is used as a spring member.

FIG. 1 and FIG. 2 are diagrams showing an embodiment of the hydraulic rotary actuator of the present invention.

This example will be explained below.

A is the base part and B is the operating part.

An annular pressure chamber 1 is formed between a base part A and an operating part B.

When viewed in the direction in which the rotational axis 2 extends, the base part A and the operating part B are opposed to each other at both ends of the pressure chamber 10, with a small gap 3 and 4 formed between them.

The values of the minute gaps 3 and 4 are determined so that the pressure liquid in the pressure chamber 1 gradually enters the minute gaps and a lubricating film is formed.

That is, gap 3 is the upper seal and gap 4 is the lower seal.

A first partition wall 5 is provided within the pressure chamber 1, extending from the operating section B toward the base section A and partitioning the pressure chamber 1.

A second partition wall 6 is provided within the pressure chamber 1, extending from the base portion A toward the operating portion B and partitioning the pressure chamber 1.

That is, the inside of the pressure chamber 1 is partitioned into a first chamber 7 and a second chamber 8 by the first partition wall 5 and the second partition wall 6.

Passages 9 and 10 are provided in the base part A, and the liquid pressurizing means and the liquid tank are connected to the first chamber 7 and the second chamber through switching valves (not shown), respectively.
It communicates with chamber 8.

An annular undulating spring member 11 that acts in a direction to displace the operating portion B upward is provided so that the reaction force of this spring member 110 is received by the base portion A.

This spring member has a plurality of waves at equal intervals.

Note that 12 and 13 are bearings, 14° and 15 are O rings, 16,
17 is a drain hole.

If it is assumed that there is no spring member 11, the weight of the actuating part B will be applied to the surface of the base part A forming the lower seal 4.

As a result, the gap between the lower seal 40 becomes narrower and the upper seal 3
The zero gap becomes wider.

Therefore, a large amount of the pressure liquid in the pressure chamber 1 flows into the upper seal 3, but hardly flows into the lower seal 4.

Therefore, pressure due to the pressure fluid is also applied to the surface forming the upper seal 3 of the operating portion B, which acts to further narrow the gap between the lower seals 4.

In this respect, by providing the spring member 11, the weight of the operating portion B can be prevented from being applied to the lower seal 4 and the upper seal 3.

Therefore, a part of the pressure liquid in the pressure chamber 1 can evenly flow between the upper seal 3 and the lower seal 4.

Therefore, a good lubricating film is formed on the upper seal 3 and the lower seal.

Note that when pressurized liquid is supplied to the first chamber 7 through the passage 9, the actuating part B rotates in the fl direction, and when pressurized liquid is supplied to the second chamber 8 through the passage 10, the actuating part B rotates in the fl direction.

In particular, in the present invention, an annular undulating spring having a plurality of waves at equal intervals is provided as a spring member, so that when a load is applied to the operating portion B, the spring member 11 is deflected.

Since this spring member attempts to return to its free height, a reaction force is generated.

The resulting forces are transmitted alternately in the circumferential direction from the troughs of the waves on the one hand to the crests of the waves on the other hand.

Therefore, the resultant force of these forces is generated at the center of the spring member.

In other words, the reaction force is generated uniformly and without bias.

Therefore, a lubricating film is well formed. Further, since this spring member can be made smaller than a helical spring, the entire actuator can be made smaller than a case where a helical spring is used as the spring member.

An example will be given of a case where the weight of the actuating part is applied to the lower seal component of the base when there is no spring member.

An example of this is the case shown in FIGS. 1, 2, and 2, where A is the operating part and B is the base part.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the hydraulic rotary actuator of the present invention, and FIG. 2 is a cross-sectional view of FIG. 1 taken along line 2-2. A is a base part, B is an operating part, and 11 is a spring member.

Claims (1)

[Scope of Claims] 1. In a device that has a base part and an actuating part that rotates based on the base part, and the axis of rotation of the actuating part is oriented in the vertical direction, the actuating part A hydraulic rotary, characterized in that an annular undulating spring member having a plurality of waves at equal intervals is provided and the reaction force of the annular undulating spring member is received by the base member. actuator. 2. The hydraulic rotary actuator according to claim 1, wherein the force acting on the actuating portion of the annular undulating spring member is approximately equal to the force required to support the actuating portion.