DE2337407A1 - Hydraulic rotary actuator - driven shaft has ring and compensating channel system - Google Patents

Abstract

Actuators for high pressure applications suffer from the problem of excessive thrusts resulting in heavy axial bearing designs and consequently bulky actuator dimensions. The ring on the shaft rests alternatively on the one or the other thrust bearing according to the sense of rotation of the actuator and hence the direction of the thrust. The channel system connecting basically the two hydraulic power connections is fitted with non-return valves of opposite sense admitting fluid pressure to such a side of the ring as to counteract the prevalent thrust.

Description

DipL-Ing. A. Spalthoff 43 eat ι. July 20, 1973

Patent Attorney l ^^ YL

Postachlassfadi 1533 Telephone (02141) 772008

File no. 21 481 S / O please indicate in the answer

MASCHINENFABRIK RUDOLF HAUSHERR & SÖHNE KG., ^ 322 SPROCK-HÖVEL / WESTF.

ROTARY DRIVE

The invention relates to a hydraulically or pneumatically actuated rotary drive with a cylinder, an output shaft and a pressure medium actuated axially in the cylinder sliding piston, which has two threads with opposite Winding sense is provided, of which one thread with an internal thread in the cylinder and the other thread cooperates with a thread of the output shaft.

In rotary drives of this type, in which the thrust movement of the piston is converted into a rotary movement of the output shaft, it is very difficult to go over to higher pressures, for example of more than 100 atmospheres, because then the pressure bearing is required Size are no longer available that can absorb the thrust of the piston. Take the thrust bearings

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then of such a size that they are more conventional in rotary actuators Order of magnitude can no longer be installed, so that their dimensions are increased accordingly have to, which, however, represents a very considerable effort.

Proceeding from this prior art, the invention is based on the object of avoiding the aforementioned disadvantages To create rotary drive of the aforementioned Aft, which is provided with a pressure relief for the bearings, so that at conventional bearing sizes can be switched to much higher pressures, or if the previous ones are retained Pressures smaller-sized bearings can be used.

According to the invention this is achieved in that the output shaft instructs an annular extension, which is supported on both sides via a bearing against the cylinder, and an annular space is provided behind the bearing on the output side, which through holes, channels or the like. once with the pressure medium supply is connected for one piston side and the other with the pressure medium supply for the other piston side, there is a check valve in each of the two connections. The storage of the output shaft is on this Way, hydrostatically relieved, so that the rotary piston cylinders can also be operated with pressures higher than 100 atü, while maintaining the previously used storage sizes or if the previous pressures are maintained with lower

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dimensioned bearings can be equipped.

The check valves are arranged so that they are opened by the pressure medium acting on the piston sides.

According to a further feature of the invention, the check valves in the end positions of the piston via lugs, plungers or the like provided on these. opened so that a pressure relief is inevitably brought about in the end positions.

An embodiment of the invention is based on the drawing explained in more detail, which shows a partially sectioned view of the rotary drive.

1 with the cylinder of the rotary drive is referred to, which at his one side is closed by the cover 2.

On the other side of the cylinder 1, the latter has an insert 3 in which the output shaft 4 is mounted. The output shaft k has a cylindrical extension 5i which carries the internal thread 6, which meshes with the external thread 7 on the pin 8 of the piston 9. The piston 9 is equipped on the other side with a further pin IO, which has an external thread 11 which meshes with an internal thread 12 of a cylindrical extension 13 of the cover 2. The cylindrical extension 13 is on the cover 2 by welding or the like.

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fastened, making the manufacture and assembly essential simplified.

The piston 9 is acted upon by means of pressure medium, on the one hand via the opening 1k and on the other hand via the opening 15 in the walls of the cylinder 1.

The output shaft k has an annular extension l6, in the end face of which the seal 17 is inserted.

A thrust bearing is provided on both sides of the annular extension l6 of the output shaft 4 and is denoted by l8, 19

Below the bearing 19 towards the output side is the annular space 20, which via the connection 21 to the opening lk for the application of one side of the piston 9 and via the connection 22 to the opening 15 for the application of the other side of the piston 9 in Connection. A check valve 231 24 is switched on in each of the two connecting lines 21, 22.

The mode of operation of the arrangement is as follows!

If pressure medium is applied to the piston 9 via the opening lk in the direction of arrow 25, the piston 9 moves in the direction of the output shaft k.

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With this movement, the piston 9 exerts a force on the bearing 19 'eier Äfot.riel * shaft k , which results from the area of this longitudinal approach 16 times the prevailing pressure divided by two. This force, which is designated as p / 2, is now countered by a counterforce which results from the annular surface, which is composed of the diameter of the seal 26 and the outer diameter of the bending 17 times the pressure. Since this annular surface is connected to the pressure supply lk for one side of this piston 9 via the valve 23, the pressure relief of the piston always acts proportionally.

Now, if the © ffuaiMg applied 15 in the direction of the arrow 27 with pressure medium, so here affects a piston force p / 2 to the bearing IS "result, however, that the Biefcitusmg 17 is made ineffective by the non-return valve 2k, creates a Pluiigerkraf t with the Area that the inner diameter of the seal 26 aal the Ifaruiek against half the piston force.

Even with Beatxfsehlagurag this piston side can through previous Determine 'the diameter and thus the areas the load the camp can be determined from the outset. Thereby it is given that high operating pressures with comparatively small bearing sizes for absorbing the piston thrust used «can be grounded.

The YerbiündtaiHigem Zt , 22 with their check valves 23, 2k

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have been drawn in schematically for the sake of simplicity, however, the arrangement of the check valves 23) is 2Ί so that they can be opened in the end positions of the piston 9 by tappets, lugs or the like provided on it.

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Claims (1)

PATENT CLAIMS: Hydraulically or pneumatically actuated rotary drive with a cylinder, an output shaft and a pressure-medium actuated, axially displaceable piston in the cylinder, which is provided with two threads with opposite turns, of which one thread with an internal thread in the cylinder and the other thread with a Thread of the output shaft cooperates, characterized in that the output shaft (4) has an annular extension (l6) which is supported on both sides via a bearing (18,19) against the cylinder (l) and behind the output-side bearing (19) an annular space (20) is provided, which via bores, channels (21,22) or the like. is connected to the pressure medium supply (l4) for one piston side and to the pressure medium supply (15) for the other piston side, with a check valve (23,24) in each of the two connecting lines (21, 22). Rotary drive according to Claim 1, characterized in that the check valves (23 »24) are arranged in such a way that they are opened by the pressure means acting on the piston sides. 3 ·) Rotary drive according to claim 1 and / or 2, characterized in that the check valves (23 »24) in the end positions of the piston (9) via lugs, plungers or the like provided on this. be opened. 409886/0229 Blank page