DE1950371A1 - Hydraulic pump with radial pistons - Google Patents

Description

Dlpl.-Phys. E. BSTZLER
Npt.-lng. W. HERKMANN-TRENTGPOHL

P ο t β η t 3 η .ν a It α • 000 Munich 23, Eigundäier Strasse 17

3436-69

SOCIETE NATIONALE D ¹ ETUDE ST DE CONSTRUCTION DE MOTEURS D ¹ AVIATION

Hydraulic pump with radial pistons.

The invention "relates to hydraulic pumps with radial pistons with a first eccentric for Control of the reciprocating movement of a first group of uniformly star-shaped around this first eccentric around distributed pistons and a second eccentric, which is from a drive shaft in synchronism with the first eccentric is set in rotation and the reciprocating movement of a second group of uniformly star-shaped around controls the piston distributed around the second eccentric, the piston numbers of the first and the second group being equal to each other equal to 3ind, each piston of the first group and each piston of the second group being displaceable in a single cylinder is with which he a chamber of variable volume

00Ö82A / 1233

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defined with a suction valve and a Druok or Ford valve.

In such a pump corresponds

is known to a piston of the first group executing a suction stroke (or delivery stroke) a piston of the second group, which executes a delivery stroke (or suction stroke). These two pistons are hereinafter referred to as "counter-rotating pistons".

The invention relates in particular when

also not exclusively, such hydraulic pumps, * which with a high delivery pressure in the. Of the order of 250 ^ up to 350 bar, as used in aviation for the hydraulic control circuits on board aircraft.

Such pumps have numerous advantages, since the peripheral speeds between the eccentrics and the parts in contact with them (sliding shoes) The pistons are small, so the pump has a long life even when the delivery pressure is high.

The previously used to regulate the delivery rate

Such pumps proposed means, however, have numerous Disadvantages, in particular due to their intricate mechanical construction, as they are generally the suction valves of a actuate each chamber of variable volume to control it during part of the delivery stroke of the piston, which can be displaced in these chambers of variable volumes, in an open position to keep.

The subject of the invention is a pump in which the pumps used to regulate their delivery rate Means are simple, vigorous and reliable.

The invention also has a pump for

Object whose work at part load under better conditions than with the previously known pumps.

The invention also has a pump for ^;

Subject at v / elcher when they are with very low capacity (of the order of 1/10 of their nominal power) works, only a small number of pistons work.

For this purpose, according to the invention contains a

Such pump connecting lines, each soft one through variable chamber defined by a piston of the first group

009824/1233

; '■ - ■

Connect volume with the chamber of variable volume, which by the piston of the first group rotating in opposite directions Piston of the second group is defined, in each of these connecting lines connected connecting links, and controllable control means which operate the closure members so that each closure member during a part one revolution of the drive shaft corresponding controllable time can remain open, so that during this part of a Revolution that of a piston executing a delivery stroke required liquid in the chamber of variable volume passes, the piston of which is in opposite directions and thus an äaftg stroke executes.

As a result, the total delivery rate of the pump can between a (a value zero of the part of the revolution during which each closing link is open, a corresponding maximum value and a (the maximum value of the part of the revolution during which each locking link remains open, corresponding) minimum value can be regulated, whereby this minimum value can be zero, if the value of the part of the revolution during which each locking link is open is equal to the unit.

The invention is explained below by way of example with reference to the drawing.

Pig. 1 is a schematic axial section of a hydraulic pump according to the invention.

Pig »2 is a pictorial view some essential parts of a pump according to the invention.

Pig. 3 to 6 are schematic representations for explaining the mode of operation of a device according to the invention Pump.

Pig * 7 is a diagram also showing the operation of a pump according to the invention.

As shown in Pig * 1 and 2, contains

the pump has a first eccentric 1a for controlling the back and forth moving movement of a first group of uniformly Piston 2a distributed in a star shape around this first eccentric 1a and a second eccentric 1b, which is located in the Synchronism with the first eccentric 1a rotates and the out

00982: / 1223

and forward movement of a second group of uniform Controls piston 2b distributed in a star shape around this second eccentric 1b.

The number of pistons in the first group (piston 2a) and the second group (piston 2b) are the same.

Each piston 2a and 2b of the first and

the second group can be moved in a cylinder 3a or 3b, with which it defines a chamber of variable volume 4a or 4b, which is designated as a whole by 5 and 6, respectively Suction and pressure valves are assigned.

The two eccentrics 1a and 1b are expediently attached to the same drive shaft ψ.

So in this pump corresponds to one

a Saußhub (or delivery stroke) executing piston 2a of first group a delivery stroke (or suction stroke) executing piston 2b of the second group, so that these two pistons are opposite. ,

According to the invention, this hydraulic pump now includes connecting lines 8, each of which has a The variable volume chamber 4a defined by a piston 2a of the first group connects to the variable volume chamber 4b, which connects to the piston 2a of the first group of opposing pistons 2b of the second group defined is, in each connecting line 8 arranged connecting links 9 »and controllable control means which actuate the locking members 9 so that each locking member during one corresponding to a part of one revolution of the drive shaft 7 controllable time can remain open, so that during this part of a revolution the one executing a delivery stroke Piston delivered liquid passes into the chamber of variable volume, the piston of which is in opposite directions and.somit performs a suction stroke. It can then obviously without actuating the suction valves 5 of the pump, the total delivery rate of the Pump between a maximum value (corresponding to a value zero of the part of the revolution during which each closure member is open) and a (the maximum value of the part of the revolution during each soft Closing member remains open, corresponding) minimum value can be regulated, this minimum value can be zero if the

0098.24 / 1233 λ

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Value of the part of a revolution during which each locking link is open, is equal to unity.

For this purpose, the I ¹ Ig. 1

and FIG. 2 can be used. At this each closure member 9 is formed by a slide 10 which is displaceable in a cylinder 11 ', in which the both "sections of the connecting line 8 in question open out, the one formed by the slide 10 and the cylinder 11 Arrangement is designed so that it provides the connection between these sections and thus between the corresponding chambers variable volume 4a and 4b corresponding to the opening or the closed position of the slide 10 in the cylinder 11 is established or interrupted, the slide 10 Evenly distributed in a star shape around the drive shaft 7 and pressed against it by return means 12.

The controllable actuation means of the closure members 9 are connected to the drive shaft 7 by a device is formed coaxially and rotating with this bushing 13 which is inclined in one to the axis of the drive shaft 7 Curve path 14 lying flat has. The bushing 13 is around a fixedly connected to the drive shaft 7 or a part thereof forming sleeve 15 slidably displaceable so that it is displaced by a regulating mechanism between two limit positions can be, namely a first limit position in which each slide 10 by its return means 12 against the socket 13 is held printed, and a second limit position, - in which during part of a revolution of the drive shaft 7 each. Slide 10 by its return means 12 against the sleeve 15 is held printed, the thickness of the sleeve 13 at least approximately equal to the distance between the open position and the closed position, which each slide 10 can take.

In Pig. 1 and 2, the slides 10 take their closed position on when they are pressed against the socket 13 »

Under these conditions, the

first limit position of the socket 13 of the greatest total delivery rate of the pump, since the part of one revolution of the drive

009824/1233 ■■ '

wave 7 »during which each locking member 9 is open,. has the value zero. When the bush 13 assumes this first limit position, which is shown in Fig. 1 and 2 as well as in Fig. 3 (in which the same reference numerals denote the same parts as in ._... Figs. 1 and 2) , the slides 10 of the locking links are held against the bushing X3 .

The second limit position of the socket 13

corresponds to the smallest total delivery rate of the pump, since the part of a revolution of the drive shaft 1 during which each closure element 9 is open has its maximum value.

If, as assumed above, the delivery rate of the pump can be zero, this is part of a revolution the .Drive shaft 7 equal to the unit. When the socket 13 this second in Fig. 6 (in which the same reference numerals denote the same parts as in Figs. 1 and 2) shown Assumes limit position, the slide 10 of the Yerscitlussglieder 9 held down against the sleeve 15 *

In Fig. 4 and 5 (in which the same

Reference numerals denote the same parts as in FIGS. 1 and 2) two intermediate positions of the socket 13 are shown. In Fig. 4, the part of one revolution of the drive shaft 7 » during which each closure member 9 is open, about 1/4, while in Fig. 5 the part of one revolution of the drive shaft 7 » during which each closure member 9 is open, about 1/2. amounts to.

In Fig. 7, which is a graph "in

which as ordinates the revolutions η of the drive shaft and the stroke χ of the piston are entered as the abscissa, is a first representing the stroke of a piston 2a of the first group

Curve 0 and a second curve C, drawn, showing the stroke a υ - - - _{t #}

of the piston 2b rotating in the opposite direction to the piston 2a of the first group the second group represents. './■' ".. '

The position shown in Fig. 3 of

Rifle. 13 corresponds to the abscissa 0 in Fig. 7. It never exists a connection between the variable volume chambers 4a and 4b, which correspond to the pistons 2a and 2b, respectively Strokes are represented by the curves C and O ^.

The total delivery rate of the pump is

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by the delivery strokes of the pistons 2a and 2b of the first and the second group delivered.

The position of the socket 15 shown in FIG. 4 corresponds to the abscissa 1/4 in FIG. 7. During a 1/4 turn the drive shaft 7 is a connection between the Chambers of variable volume 4a and 4b, which correspond to the pistons 2a and 2b, the strokes of which are indicated by the curves C and

, - ■ a

Oj ₃ are shown

During half of the delivery stroke of the piston 2a. the first group will alter the fluid in the chamber Volume 4b of the piston 2b of the second group required, which then carries out half of its suction stroke »The delivery rate of the pump is determined by the second half of the delivery stroke a the piston 2a of the first group and delivered through the entire delivery stroke of the piston 2b of the second group.

The position of the socket shown in FIG 13 corresponds to the abscissa 1/2 in Fig. 7 »during 1/2 a revolution of the drive shaft 7 there is a connection between the chambers of variable volume 4a and 4b, which the pistons 2a and 2b, respectively whose strokes are represented by curves C and C.

• &

are. _

During the entire delivery stroke of the piston 2a of the first group will mutate the liquid in the chamber Volume 4b of the piston 2b of the second group promoted, which then executes its entire suction stroke, the delivery rate of the pump then only through the delivery strokes of the piston 2b of the second group is delivered.

The position of the socket 13 shown in FIG. 6 corresponds to the abscissa 1 in FIG. 7. There is a constant Connection between the chambers of variable volume 4a and 4b, which correspond to the pistons 2a and 2b, their strokes through the curves C and Q. are shown.

To reduce the length of the connecting lines, it is expedient to use the first and the second eccentric 1a and 1b to be arranged so that they are offset by about 180, so that the opposing pistons in adjacent radial Directions lie.

Do this if k is the number of pistons

009824/1233

the first or the second group denotes the two Eccentrics 1a and 1b expediently at an angle of 180 ° - | r— offset against each other.

As shown in Fig. 2, then

the two eccentrics 1ä and 1b are conveniently placed against each other, in order to reduce the tilting moment acting on the drive shaft 7, the closure members 9 then being arranged laterally opposite the pistons 2a and 2b. -

The closure gleather 9 are preferred

arranged radially so that their axes XX lie between the axes Y -Y_ and Y ₁ JY ^ j of the chambers of variable volume 4a and 4t> the opposing pistons 2a and 2b In other words, in a projection on one to the drive shaft ^ 7 In the vertical plane, the axis XX forms the bisector of the axes

The determining the position of the socket 13

Control mechanism can expediently be formed by a mechanism controlled by the delivery pressure of the pump. He contains a working cylinder 16, which against a return spring 17 on the socket 13 via a rotatable part 18.-__-_ acts, ie a distributor 19, which on the working cylinder 16 brings either the delivery pressure of the pump or the suction pressure of the same to action, depending on whether the delivery power the pump should be reduced or increased. This Distributor 19 is actuated by the delivery pressure of the pump.

The hydraulic pump according to the invention has numerous advantages, including the following * - "" ..

- The means used to regulate the flow rate of the pump are simple, powerful and reliable;

- Working under partial load is favored by the fact that during part of a revolution of the drive shaft the liquid conveyed by a piston executing a conveying stroke is supplied to chambers of variable volume, r is, in which piston perform a suction stroke, whereby the Suction work is reduced during this part of a revolution, and what helps to keep the piston in question against its Press eccentric;

'.-. "' ..- if the pump has a very low delivery rate (of the order of 1/10 of the maximum capacity)

0 0 9 8 2 Λ / 1 2 T 3

works, only a small number of pistons lead to the second Group simultaneously delivery strokes off ► If the pump has two Piston groups with seven pistons each, each piston in the second group works for a delivery rate of the order of magnitude 1/10 of their maximum output one after the other during the end of its delivery stroke, and two never work Piston at the same time, which is used to relieve the ball bearings Storage of the drive shaft during operating times with very low delivery rates contributes.

This latter point makes one very

Significant advantage of a pump used in the aviation industry for the control circuits on board aircraft, because such a pump is generally only at full load the take-off and landing maneuvers, which require a large transport capacity (control of the landing gear, the engine-raising flaps, air brakes, etc.) j during the pump works with a very low delivery rate during the stabilized flight, since then the maneuvers are only one require very little power (compensation of leaks, on-board steering, S-control of stabilizing flaps etc. *).

009824/12 33

Claims (1)

- 10 - -3436-69 patent claims 195037 '* _r V ■■■■■. : ..- .- ■. - * ■ ... ■ '.: - ■' ■■ "- ■■■ ■ - ■ - ■ 1 ·) / Hydraulic pump with radial. Piston with a first eccentric, which the back and forth walking movement of a first group of uniformly star-shaped controls distributed around it piston, and a second eccentric, which is set in rotation by a drive shaft in synchronism with the first eccentric * and the controls the reciprocating movement of a second group of pistons evenly distributed in a star shape around it, where the pistons ^ numbers of the first and second group are the same, each piston of the first and the second Group is displaceable in a single cylinder, with v / elchem he then defines a chamber of variable volume, which a suction valve and a pressure valve are assigned, characterized by connecting lines (8) for connecting a each defined by a piston (2a) of the first group Chamber of variable volume (4a) with the through to the Pistons (2a) of the first group "counter-rotating pistons (2b) of the second group defined chamber of variable volume (4b), attached to each connecting line (8) closure members (9), and adjustable means for actuating the locking links (9), such that each closure member during a a part of a revolution of the drive shaft (7) corresponding controllable time can be kept open so that the of a piston executing a delivery stroke during this part One revolution delivered liquid enters the chamber of variable volume, the piston of which rotates in the opposite direction to the former and thus performs a suction stroke. 2) Pump according to claim 1, characterized in that that each closure member (9) through a slide (10) which slides in a cylinder (11) in which the two parts of the relevant connecting line (8) open, with the through the slide (10) and the cylinder (11) formed arrangement is designed so that it makes the connection between these parts and thus the connection between the corresponding chambers of variable volume (4a and 4b) establishes or interrupts, depending on whether the slide 009824/1233: (10) in the cylinder (1T) its open or closed position occupies, the slide (10) uniformly star-shaped are distributed around the drive shaft (7) and are pressed against this by Hückholmittel (12), and that the adjustable means for actuating the connecting links (9) through eirie coaxial with the drive shaft (7) and with this rotating sleeve (13) are formed, which one in one to the axis of the drive shaft (7) inclined Has level inclined cam track (14) and around a sleeve (15) fixedly connected to the drive shaft (7) or forming part of the same can slide in such a way that it can be shifted by a control mechanism between two limit positions, namely a first limit position, in which each slide (10) by its return means (12) pressed against the socket (13) v / ird, and a second Limit position in which one rotation during a part the drive shaft (7) each slide (10) through its Return means (12) is held pressed against the sleeve (15), the thickness of the bushing (13) being at least approximately the same is the distance between the open or closed position which each slide (10) can assume. 3 ·) Pump according to claim 2, characterized in that the slides (10) assume their closed position when they are held pressed against the bushing (13). '4 ×) pump as claimed in claim 3 »that the first limit position of the bush (13) corresponds to the largest GesamtforderIeistung of the pump, since the part during which each Verschlussgiied (9) is open one revolution of the drive shaft (7), the Has a value of zero. 5 ·) Pump according to claim 3, characterized in that the second limit position of the socket (13) of the corresponds to the smallest total delivery rate of the pump, since the Part of one revolution of the drive shaft (7) »during which each closing link (9) is open, has a maximum value, 6 ·) Pump according to claim 5, the delivery rate of which can be made zero /, characterized in that the part of one revolution of the drive shaft (7) is equal to the unit is. ; 009824/1233 - 7 ·) Pump according to claim 1, characterized in that the first and the second eccentric (1a and 1b) are offset from one another by about 180. in such a way that the opposing pistons lie in adjacent radial directions. 8.) Pump according to claim 7, characterized in that the first and the second eccentric (1 a and 1b) offset from one another by an angle of 180 ° ί 4 ^ are, where k. the number of pistons of the first and second Group. 9.) Pump according to claim 8, characterized in that "that the first and the second eccentric (1 a and 1b) are placed against one another and the closure members (9) are arranged to the side of the pistons (2a and 2b). 10.) Pump according to claim 9> characterized in that the closure members (9) are arranged radially are that their axes (X-X) are between the axes (Y-Y and Y ^, - Y ^) of the chambers of variable volume (4a and 4b) of the opposing pistons (2a and 2b) lie. 11.) Pump according to claim 10, characterized in that that the projections of the axes (X-X, Y_-Y_ a a and Y ^ -Y ^) on a plane perpendicular to the drive shaft (7) are arranged so that the axis (X-X) forms the bisector of the angle formed by the axes (Y -Y and Y, -Y,). 12 ·) Pump according to claim 2, characterized in that the regulating mechanism determining the position of the bushing (13) is actuated by the delivery pressure of the pump and one against a return spring (17) on the socket (13) a rotating part (18) acting working cylinder (16) and a distributor (19) which either brings the delivery pressure of the pump to action on the working cylinder (16) when the delivery rate of the pump is to be reduced, or the suction pressure of the pump when the delivery rate the pump is to be increased, this distributor (19) being actuated by the delivery pressure of the pump. 00982Λ / 1 233 BAD ORIGiNAL