DE1950253A1 - Hydrostatically relieved control with low flow resistance - Google Patents

Description

170270

Hydrostatically relieved control with low flow resistance.

The invention relates to a hydrostatically relieved control with a control disk of low flow resistance, especially for hydraulic machines.

It is the aim of the invention to provide a controller whose Flow resistances are as low as possible. It is also an aim of the invention to achieve that controls even after long Operating time and at different! Temperatures with if possible tight sealing gaps work to keep leakage losses low to keep. On the other hand, minimal frictional torques should occur in order to ensure high start-up efficiencies and to limit the development of heat.

It is known to use centrically running control slides or eccentric controls in hydraulic machines; However, these do not release the flow cross-sections to the required extent and cause a relatively high flow resistance ₀

It is known to keep the sealing gaps to a minimum by narrowing the manufacturing tolerances or using washers; However, due to wear and tear and temperature differences, the original values are subject to a disadvantageous change. Rotary valves with piston rings are also known; Such rotary valves seal well with the piston rings, but they do not between the reversal or relief kidneys a considerable Leakage oil flow through and generate a relatively high locking torque, due to the sealing principle of the piston rings. It is also known to have an axially acting, centrally running To seal the control slide by a central pressure system; · However, the pressureless side of the control spool is function-related pressed with high force, which in turn causes a relatively high seizure torque. There are eccentric

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Erungen known that one for the purpose of an automatic sealing gap compensation can share? such eccentric controls However, they have the disadvantage of a high flow resistance and, due to their construction, a certain functional uncertainty.

The invention is based on the object, the control-related To reduce flow resistance. The invention is based on the further object of creating a controller the only one contact pressure required for sealing acts on the control disc and in the independent of manufacturing stole- " satchels, working pressures, wear and tear and temperature differences, the sealing gaps are kept to the desired minimum values will.

According to the invention is an eccentric control kidney of the control disk connected via a connecting channel with an eccentrically arranged deflection channel, which is connected with a central feed or drain hole is connected} as a result of this, large cross-sections with low flow resistances are used and in the control frelo

According to a further embodiment of the invention sits the dem Part of a thrust washer used to compensate for the gap eccentrically on the control disc. This causes the pressure medium to flow axially into the opening of the pressure disc, is deflected and through a connecting channel into the control kidney belonging to the opening of the pressure disk and from there into the cylinder ducts. as If this is successful, the control disk is pressed against the control surface in such a way that that the force acting on the pressure disk side of the control disk is somewhat greater than that of the pressure kidney Control disk resulting force and both lines of force coincide essentially

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According to one embodiment of the invention, a pressure ring is located between the control disc and the pressure disc, which ensures additional pressing of the control disc and pressure disc against the sliding surfaces when pressure is applied alternately. In a further modification of the invention, this pressure ring can be replaced by an elastic seal. If the additional pressing is dispensed with, it is also possible according to the invention to seal the control disk and pressure disk directly against one another.

In one embodiment, it is necessary to turn the seal (s) between the control disk and the pressure disk into static seals According to the invention, the thrust washer is attached to the control disk in such a way that it cannot rotate but is axially displaceable. This can, for example, by means of a pin or by centering on a federal government whose center line differs from the center line of the Pressure disc opening deviates, happen; it is also possible to hold the pressure disc by means of a pin, which protrudes from the control disk.

The advantages that can be achieved with the j-r "indung are special in low leakage losses, high start-up efficiency, low heat generation and low flow resistance.

An embodiment of the Krfindun ^ is shown in the drawing and is described in more detail below. It show: Pig. 1 the control-side part of a hydraulic motor with a schematically drawn control; Pig. 2 fine dense mock-up grain pen tiered control

in the assembled state with a view from the right and left; Version with pressure ring and retaining collar} P ⁿ ig. 3 eint üicht'spuLt - Kempens torte ^c > U <ü <irunQ _l

Version with sealing ring acting as a pressure ring and moisture retaining pin;
4 eiru- dense> pci (t - Kctnpiiniai'tfi-fc Vtt / j'irurK /.

Version without printer ", but with pencil"

1 0 9 8 1 7/0 B U 0 BAD ORiGiNAL

Fig. 1 shows the control-side part of a hydraulic motor of known design »e.g. in radial piston design with control 17 °

The pressure medium enters the hydraulic motor, for example, through inlet 1, arrives via deflection channel 2 and connecting channel 18 of control 17 in its control kidney 19 »where it enters the Cylinder channel 3 is controlled. After the pressure medium has given its energy to the crankshaft 16 via pistons or the like, it flows through the cylinder channel 3a back to the control 17, namely first in its control kidney 19a, then through a Turning 4 or bores in the annular channel 20 and in the Äuslaß 5 of the hydraulic motor. The flow can of course can also be done in the opposite direction »

1&
Fig. 2 ^r a dichi & polt - compensated sft? Ut? Rting ₍ . Namely: Fig. 2b a longitudinal section,

2a view from the right of the longitudinal section according to Fip. 2b, 2c view from the left of the longitudinal section according to Fip. 2b _o

In the control disk 7, a socket 10 with an internal four-bevel is inserted in a rotationally fixed manner, into which the crankshaft engages. The crankshaft and the control disk 7 thus run at the same speed. On the eccentric 21 of the control disk 7 is seated. Pressure ring 9 »which is sealed against the control disc 7 by means of a seal 13 and can be moved axially. The thrust washer 8 and the thrust ring 9 are sealed against one another by means of a seal 12. The control disc 7 and the pressure disc 8 are under the action of one or more compression springs 11. The pressure disc 8 is secured against rotation by centering it on the collar 15 of the control disc _{or the like}

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BADORfGlNAL

1960253

The mode of operation of the control is as follows In the state of the working medium, the control disk 7 and the pressure disk 8 are pressed apart in a sealing manner by the springs 11 φ Thus there is practically no connection between inlet 1 and outlet 5 and crank chamber 22 (Fig. 1), since the sliding surface 14 of the Control disk rests on the control surface 23 of the hydraulic motor, and the sliding surface Ha rests on the cover plate 24. Will inlet when pressurized oil is applied, the control disc 7 and pressure disc 8 are additionally pressed apart by hydrostatic pressure, which increases the sealing effect »The sealing effect is further strengthened by means of the pressure ring 9.

Is outlet 5 pressurized oil j so delivers the same effect a <> While pressurizing the inlet 1, the thrust washer 8 is comparable to a sliding block, it can be at pressure from outlet 5 having an inverse d.iw, compare externally applied shoe.

The control can now be designed in such a way that the pressure forces acting on the control disk 7 on the disk side for the purpose of secure sealing are slightly greater than the forces originating from the respective control kidney 19 or 19a} The same applies to thrust washer 8 “Support with it mainly two columns of pressure oil against each other, and only the residual forces required for sealing generate friction.

3 shows a modification of the control according to the invention according to FIG. 2, namely the collar 15 for holding the pressure disk 8 replaced by a pin 15a} the socket 10 with a square socket inserted in a rotationally fixed manner in the control disk 7 is replaced the recess 4 in the control disk 7 is replaced by a keyway directly introduced into the control disk by radial bores 4aj shown in Fig. 2 in the form of Bores formed connecting channel 18 is replaced by

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a kidney-shaped recess 18a, in which the flow rate of the pressure medium is largely constant over the entire cross section is; the pressure ring 9 in conjunction with the seals 12 and 13 is replaced by one at the same time acting as a pressure ring and seal seal 9a.

Pig. 4 shows a further modification according to the invention of FIG Control according to Pig. 2, the control and in particular pressure disk 8 relieved to the limit of equilibrium is. This is made possible by one or more seals 13a introduced into control disk 7 or pressure disk 8 »

The control is of course subject to further modification possibilities according to the invention, in particular with regard to it to the "desired degree of relief, fluidic optimal training, inexpensive manufacturing, choice of Pressure medium and temperature range ο For example also, instead of simple O-rings, those with support rings or metallic seals are used »

The .limitation., Of the one located on the control or pressure disc Eccentric has any shape; it can e.g. be trochoia-shaped in order to achieve even lower flow resistances and a special protection against twisting * - save.

The control disk has any shape. For example, its control kidney 19 (Pig * 2) on the eccentric side can be designed in such a way that its contour is the same or similar to that of the cutout 18a (Pig. 3). Further, the recess 4 can be over the entire width of the control disc and are drawn wider than in Fig. 2 pulled through the middle, it so that the function of the kidney-shaped control 19a accepts _β

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The pressure disc has any shape; "She can, for example by a collar, an eccentrically arranged pin or by a pin protruding centrally from the control disc secured against twisting.

Further inventive modifications of the 2rfindung are also possible in such a way that the cylinder block of the hydraulic machine can be rotated and the control is arranged in a stationary manner; in this case, a seal could be arranged in the collar 15 (FIG. 2).

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BATH ORIGINAL

Claims (1)

Claims 19 60 253 γ 1ο / Hydrostatlach relieved control with control disc, thereby characterized in that the working medium is centered in the Control enters or exits the control and is reversed off-center on the control surface. Control according to claim 1, dg that the gap compensation serving ^; Part of the thrust washer
Control disk is arranged. serving part of the thrust washer eccentric with respect to the Control according to claim 2, d.g. that the part of the control disk serving to compensate for the gap is eccentric with respect to a Thrust washer is arranged « 4. Control according to claims-f d.g. that between the control disc and thrust washer an axially displaceable thrust ring is arranged is ο 5. Control according to claims, d.g. that between the control disc and thrust washer an axial force generating seal is arranged. 6. Control according to one of claims 2, to 5 »dg, that the axially displaceable pressure disk is arranged in a rotationally secure manner - is. ■■ '.. ■ - ■ - 7. Control according to one of claims 1 to 5, d.g. that at least a control kidney in the radial direction from the axis of rotation is different in width. 1098 17/000 0 BADOi = IIGiINAL L e e r "s e i f e