US3644065A

US3644065A - Apparatus for filling the suction chamber of a pump at high-pump speeds

Info

Publication number: US3644065A
Application number: US20555A
Authority: US
Inventors: Rolf-Dieter Lettenmayer; Erich Schonherr; Egon Tittmann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1970-03-18
Filing date: 1970-03-18
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22

Abstract

An apparatus including a valve for connecting the pressure discharge conduit of a pump with the suction conduit only at high-pump speeds so that the machine driven by the pump is partly bypassed. The pressure medium is accelerated in the suction conduit and applies suction to the outlet conduit of a container for the medium, which is connected by a filling conduit and by a single groove in the valve piston, with the suction conduit so that the suction chamber of the pump is completely filled.

Description

United States :i aterit Lettenmayer et al.

[54] APPARATUS FOR FILLING THE SUCTION CHAMBER OF A PUMP AT HIGH-PUMP SPEEDS [72] Inventors: Rolf-Dieter Lettenmayer, Hirschlanden;

Erich Schonherr, Ludwigsburg; Egon Tittmann, Leonberg, all of Germany [73] Assignee: Robert Bosch G.m.b.l-l., Stuttgart, Germany [22] Filed: Mar. 18, 1970 211 Appl. No.: 20,555

[52] US. Cl ..417/300 [51] Int. Cl ..F04b 49/00 [58] Field ofSearch ..417/300,3l0; l37/ll7,497

[56] References Cited UNITED STATES PATENTS 3,059,580 10/1962 Farrell et al. ..417/300 51 Feb. 22, 1972 3,207,077 9/1965 Zeigler et a] ..4 l 7/ 300 3,465,778 9/1969 Kast I 37/1 17 3,099,284 7/l963 Thrap et al. ..l37/l 17 3,200,752 8/1965 Clark et a]. ..417/300 3,490,377 1/1970 Tittmann ..4 17/300 2,748,711 6/1956 Drude ..4 [7/300 Primary Examiner-Carlton R. Croyle Assistant ExaminerJohn J. Vrablik Att0meyMichael S. Striker [57] ABSTRACT An apparatus including a valve for connecting the pressure discharge conduit of a pump with the suction conduit only at high-pump speeds so that the machine driven by the pump is partly bypassed. The pressure medium is accelerated in the suction conduit and applies suction to the outlet conduit of a container for the medium, which is connected by a filling conduit and by a single groove in the valve piston, with the suction conduit so that the suction chamber of the pump is completely filled.

12 Claims, 9 Drawing Figures PATENTEDFEB22 m2 3. 644, 065

I sum 1 [IF 3 .L I s 26 L. .J 9-

INVENTORS Rolf -DieTer LETTEN/M YER Erich SCHU'NHERR BY Egan T/TTMA NN PATENTEUFEB22 I972 3.644. 065

sum 2 OF 3 INVENTOILS Rolf -Die7er LE TTENMA YE R Erich 5C H 07V H BY Egon Tl TTMA/V APPARATUS FOR FILLING THE SUCTION CHAMBER OF A PUMP AT HIGH-PUMP SPEEDS BACKGROUND OF THE INVENTION 7 The present invention relates to a positive displacement pump whose entire output is supplied to a consumer machine at low-pump speeds, from which machine the medium flows back to the suction conduit of the pump, preferably through a container for the medium, while in a range of higher pump speeds, the amount of medium exceeding a predetermined amount is guided away from the consumer machine and supplied to the suction conduit of the pump by a valve means. By acceleration of the medium in the suction conduit, a negative pressure is created by which an additional amount of the medium is sucked from the container, and the combined amount of the medium is decelerated in the suction conduit of the pump while its pressure is increased so that even at the highest speeds of the pump, the suction chambers of the pump are completely filled.

Pumps of this type are particularly used in motor cars provided with power steering, and are driven by the engine of the motor car. Therefore, it is necessary that the pump pumps the complete amount of pressure medium required by the power steering system even at low rotary speed during idling f the engine, since this is required for reliably steering the car. At the highest speed, about the same amount of the pressure medium is to be pumped to the power steering system. A pump which has a constant pumped output cannot perform this function. Consequently, a valve is used between the pressure outlet of the pump and the suction inlet and which responds to high rotary speed to permit passage of a part of the medium from the pressure side of the pump to the suction side so that the consumer motor of the power steering system is partly bypassed.

The difficulty arises that the suction chambers of the pump cannot be completely filled at high-rotary speeds, which causes cavitation, noisy operation, and low efficiency of the pump. Consequently, the amount of pressure medium bypassing the consumer motor, is used in an injector pump to increase the pressure in the suction chambers of the pump.

A pump arrangement of this type is disclosed in the U.S. Pat. No. 2,880,674. In the range of high speeds a control valve opens a gap leading to the suction inlet of the pump. Bores are provided in the suction conduit which are connected with the container for the pressure medium so that the amount of medium passing through the gap is accelerated and moves at the highest speed in the region of the bores so that a negative pressure is created which is applied to the bores and causes sucking of pressure medium returned from the power steering system to a container. The combined amounts of pressure medium flow into the suction chambers of the pump which are thus completely filled. This pump has a comparatively simple structure, but the efficiency of the additional suction is low so that power is lost.

In order to overcome this disadvantage, it is known to provide in a pump of this type an auxiliary injector pump. The after suction efficiency of such a pump, for example of the pump disclosed in the U.S. Pat. No. 2,829,599, is satisfactory, but the apparatus is expensive to manufacture.

SUMMARY OF THE INVENTION It is one object of the invention to provide a pump apparatus using an after-suction effect for filling the pump chambers, which does not require an auxiliary injector pump, and has nevertheless, a high after-suction efficiency.

Another object of the invention is to use the valve which is required for bypassing the consumer machine of the pump at high speed, also for connecting a pressure reducing suction conduit of the pump with a filling conduit which supplies additional pressure medium for completely filling the suction chambers of the pump.

In accordance with the invention, the movable member of the bypass valve has a single groove which establishes at all times and in all positions, communication between a filling conduit leading to a container for the pressure medium, and the suction conduit of the pump. The cost of the pump of the invention is substantially lower than the cost of the pump with auxiliary injector pumps, while the pump of the invention has almost the same efficiency. This can be explained by the fact that the stream of pressure medium from the pressure medium container flows directly to the surface of the shiftable member of the valve means, and produces there a high-flow velocity. similar to the effects of an injector pump.

One embodiment of the invention comprises a pump having pressure conduit means including first and second pressure conduits supplying a pump medium to a consumer means, a suction chamber, and suction conduit means connecting the suction chamber with the consumer motor and including a suction conduit connected with the pump chamber, and a filling conduit, which is preferably connected with a container to which pressure medium is returned from the consumer motor; and biased valve means having a normal position connecting the first and second pressure conduits and a regulating position for connecting the first pressure conduit with the suction conduit. The valve means is responsive to a predetermined pressure of the medium in the first pressure conduit obtained at a predetermined speed of the pump, to move to the regulating position whereby a part of the pumped medium bypasses the consumer means and creates suction in the suction conduit.

The valve means has a valve piston portion, formed with a single groove, for communication between the filling conduit and the suction conduit in both the normal and regulating positions. As a result, an amount of medium is sucked by the suction conduit in which the speed of the medium is substantially increased, and this amount is supplied from the filling conduit and the container and flows into the suction chamber completely filling the same.

Preferably, the pump includes a body formed with a cylindrical valve bore in which the vale piston is mounted for axial movement. The pump body is also formed with the first and second pressure conduits, and with the suction conduit and filling conduit. The suction and filling conduits have ports opening into the valve bore.

The valve piston is mounted in the valve bore for axial movement, and pressure chambers are provided on opposite ends of the piston and connected by a throttle means. The first pressure conduit is connected to one of the pressure chambers and causes displacement of the piston to the regulating position when the pressure in the pump exceeds a predetermined pressure at a predetermined number of revolutions.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a sectional view of one embodiment of the invention;

FIG. 2 is a cross-sectional view taken on line 11-11 in FIG. 1;

FIG. 3 is a sectional view taken on line III-III in FIG. 2;

FIG, 4 is a fragmentary sectional view taken on line IV-IV in FIG. 2;

FIG. 5 is a fragmentary sectional view corresponding to FIG. 2, and illustrating a second embodiment of the invention;

FIG. 6 is a sectional view taken on line VI-VI in FIG. 5;

FIG. 7 is a fragmentary sectional view illustrating a detail of FIG. 6;

FIG. 8 is a fragmentary sectional view corresponding to FIG. 6, but illustrating a modification of the valve means; and

FIG. 9 is a diagram illustrating the variation of the pumped amount of pressure medium depending on a number of revolutions ofthe pump.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to the embodiment of FIGS. 1-4, the housing of a displacement pump includes a left body 1, having a boss fitting into the cavity 2 of a right body 3. A rotor 4 rotates in the cavity formed between bodies 1 and 3, and has vanes 5 guided in substantially radial slots in a central rotor part, and having outer ends in sliding contact with the inner surface ofa ring 6 whose center is eccentric to the axis of rotor shaft 7 which is mounted in a bearing 8 in housing body 1. Ring 6 is fixedly secured to housing body 3, for example by pins located in registering bores of bodies 1 and 3, and in bores passing through ring 6 in axial direction, as shown in FIG. 1.

Due to the eccentric position of ring 6, a pressure chamber 9 and a suction chamber 9a are formed on opposite sides of the central rotor part, and vanes 5 move into and out of the slots in which they are mounted.

A first pressure conduit 10 connects the pressure chamber 9 with a bore 11 in body 3 in which a closure member 12 closing bore 11 is fixedly secured. Bore 11 is directly connected with a coaxial bore 13 of smaller diameter, in which a valve means 15 including a piston 14 is mounted for axial movement.

Closure member 12 has a central bore composed of two

bore portions

16 and 17 of different diameter. A piston rod of piston 14 projects through bore portion 17 into bore portion 16, and is guided in the same for axial movement. Bore portion 17 is open toward the bore 13, and also has a radial slot 18 opening into the pressure conduit 10 so that the chamber formed in the bore portion 17 is filled with pressure medium, exerting pressure against the adjacent end face of piston 14. A spring 23 in the chamber 22 formed by piston 14 in the end of bore 13, biases piston 14 toward the closure member 12.

As best seen in FIG. 1, closure member 14 has a circumferential groove 19 which is separated from slot 18 by wall 18', and communicates with a second pressure conduit 20 which is connected to the hydraulic motor driven from the pump which may be part of a power steering system. A connecting conduit 21, see FIGS. 1 and 3, connects through groove 19 and pressure conduit 20 with the chamber 22.

Wall 18 of member 12 has a throttle opening 25, see FIG. 1, connecting the chamber in bore portion 17 with the groove 19, so that a first pressure conduit 10 communicates with groove 19. second pressure conduit 20, connecting conduit 21, and chamber 22 through the throttle opening, so that the pressure in chamber 17 is greater than chamber 22, but at low speeds of the pump, the pressure difference is insufficient to overcome the biasing force of spring 23.

A suction conduit 24 has a port in bore 13 in the proximity of member 12 and pressure chamber 17. The axis of suction conduit 24 is perpendicular to the axis of bore 13 and located in a common plane with the same. As best seen in FIG. 1, suction conduit 24 extends toward the other pump body 1, in which a conduit 24' communicating with suction conduit 24 is formed. Suction conduit 24 has a gradually increasing diameter. and branches into two diffusor conduits 24 connected with suction chambers 90 ofthe pump.

Throttle bore 25 has an axis defining an angle between 5 and 10 with the axis of suction channel 24 as viewed in clockwise direction in FIG. 1. However, throttle opening 25 and suction conduit 24 are not connected to each other since throttle opening 25 connects

pressure conduits

10 and 20.

A filling conduit 26 whose axis is perpendicular to the axis of suction conduit 24, but spaced from the same, see FIGS. 2 and 3, and has a port opening into bore 13. The axis of filling conduit 26 also crosses the axis of central bore 13 spaced from the same. A small cutout 27, see FIG. 3, of triangular shape connects bore 13 with the port of suction conduit 24 in the region of a deep groove 29 in piston 14 in which the port of filling conduit 26 opens.

As shown in FIG. 2, filling conduit 26 is connected with a container 28 into which the pressure medium is discharged from the consumer motor driven by the pump.

The groove 29 in piston 14 of valve means 15 extends in axial direction almost for the entire length of piston 14, and

has a flat bottom located below the axis of filling conduit 26, as best seen in FIG. 4. One end face 30 of groove 19 is slanted, as best seen in FIG. 3 for guiding the fluid medium from the port of filling conduit 26 to the port of suction conduit 24. Piston 14 has an axially extending peripheral slot 32 into which a pin 31 projects so that displacement of piston 14 against the action of spring 23 takes place in axial direction without any rotation of piston 14 in bore 13.

Referring to the diagram of FIG. 9, which indicates the variation of the pumped amount 0,, depending on the number n of revolutions of the pump, at a low-rotary speed and number of revolutions, the amount of pressure medium 0,, is equal to the amount Q required by the load of the consumer motor. All the pressure medium in pressure chamber 9 flows into the first conduit 10, slot 18 and member 11, chamber 17, throttle 25, groove 19, and second pressure conduit 20 to the hydraulic consumer motor, not shown. The pressure medium discharged from the consumer motor flows into container 28 and from there through filling conduit 26, the single groove 29, and

suction conduits

24, 24 into the suction chambers 9a of the pump.

A pressure drop occurs at throttle opening 25, so that the pressure in chamber 17 is higher than the pressure in groove 19, connecting conduit 21, and chamber 22.

In the lower speed range of the pump, until the point A in FIG. 9 is reached, the differential pressure between chamber 17 and chamber 22 is insufficient to displace piston against the force of spring 23.

If the speed of the pump would be further increased, without taking additional measures, the suction effect of the pump, and the negative pressure in suction chamber 9a, would be insufficient to completely fill the suction chambers 9a, the flow would be interrupted and cavitation phenomena would take place, substantially reducing the efficiency of the pump.

However, in the above-described apparatus, the differential pressure produced by the throttle 25 between

chambers

17 and 22 is sufficient at higher speeds to displace piston 14 against the action of spring 23, so that between the end face of piston 14, which moves away from member 12, and the port of suction channel 24, a gap is formed whose width gradually increases as piston 14 is pressed to the right, as viewed in FIG. 3 against the action of spring 23.

An amount of pressure medium Q bypasses the consumer motor and flows through the gap into the suction channel 24. The amount of pressure medium Q is rapidly accelerated downstream of the gap formed by piston 14, so that its pressure is reduced. The negative pressure thus created in suction conduit 24 applies suction to the filling conduit 26 through the groove 29 so that pressure medium flows from container 28 through groove 29 into suction conduit 24, and from there through diffuser conduits 24 into the suction chambers 9a. Without the use of pressure medium Q, for producing additional suction, the negative pressure in the suction chambers 9a of the pump would be insufficient to obtaining a complete filling of the same. It would not be assured that the entire amount of pressure medium Q which flows from the consumer motor to the container 28, would be pumped into the suction pump chambers 9.

The diffusor conduits 24 are provided for reducing the speed of the combined amounts of pressure medium Q Q +Q so that the pressure of the pumped pressure medium is again increased before entering the suction chambers.

The construction of piston 14 with the groove 29, permits it to directly connect the filling conduit 26 with the suction conduit 24 while the stream of the additional medium pumped from container 28 flows along the guide face 30 into suction conduit 24, as best seen'in FIG. 3. This construction results, as has been shown by tests, in a particularly good after suction effect, which can be compared to the results obtained by an auxiliary injector pump.

Referring now to the embodiments shown in FIGS. 5 and 6, the general arrangement corresponds to the construction shown in FIGS. 1 to 3, and only the valve means designated 35, is differently constructed in the embodiment of FIGS. 5 and 6,

A bore 36 in the pump body contains a slide piston 37, and forms in bore 36 on one side a pressure chamber 46 closed by a closure member 50, and communicating with the pressure conduit 10, and on the other side a pressure chamber 46a in which a spring 35 is located for urging piston 37 toward the right as viewed in the drawing, into abutment with closure member 50.

Piston 37 has a central inner axially extending conduit 38 extending into a cup-shaped member 39 which is secured to piston 37, and is formed with a throttle opening 40 connecting the inner conduit 38 with the pressure chamber 46. Cupshaped member 39 may be integral with piston 37, or screwed into the same.

On the outer peripheral surface of piston 37, a single elongated longitudinally extending groove 41 with inwardly slanted end faces is provided. Groove 41 does not communicate with the inner conduit 38. An elongated cutout 42 is placed angularly spaced 90 from groove 41, and connects the inner conduit 38 with a shallow groove in the peripheral surface of piston 37, which communicates with the pressure conduit 51. Diametrically opposite groove 41, a guide groove 43 is located which is engaged by a guide pin 44 which prevents rotation of piston 37, and permits axial movement of the same.

A suction conduit 47 has a port opening into bore 36, and is positioned so that its longitudinal axis defines an angle smaller than 90 with the longitudinal axis of bore 46. A filling conduit 48, which is connected by a bore 49 with the container 28 for a medium, not shown in FIGS. 5 and 6, extends at an acute angle to the suction conduit 47, and also to the axis of bore 36. Suction conduit 47 and filling conduit 48 intersect near bore 36 and form a common elongated port directly communicating with the groove 41, which connects the suction conduit 47 with the filling conduit 48. Suction conduit 47 corresponds to the suction conduit 24 described with reference to FIGS. 1-4 and is connected with the suction chambers of the pump through diffuser conduits.

A chamber 46a in which spring 45 is located, is connected by a damping throttle opening 38a with the inner conduit 38.

During operation of the pump at low speed, the pressure medium flows from the pressure chambers 9 of the pump to the first pressure conduit 10, to the pressure chamber 36, and through throttle 40 into the inner conduit 38, and out of the same through cutout 42 into a second pressure conduit 51 which is connected with the consumer motor, not shown. The pressure in chamber 46a is lower than the pressure in the first pressure conduit 51 and in pressure chamber 46 due to the effect of throttle 40 and throttle 38a.

At a predetermined pressure difference which occurs at a predetermined high speed of the pump, the pressure in chamber 46 and pressure conduit overcomes the counterpressure provided by spring 45 and the fluid pressure in chamber 46, and piston 37 is moved to the left as viewed in the drawing so that the sealing flange 37 opens a gap in the port of suction conduit 47 through which the medium flows out of chamber 46 into suction conduit 47. The acceleration of the medium flowing through the small gap into the wide suction conduit 47, produces a suction effect in conduit 47 by which additional medium is sucked from the container 28, not shown in FIGS. 5 and 6, conduit 49 and filling conduit 48 into the suction conduit 47, so that the suction chambers of the pump are completely filled by the combined amounts of medium flowing in suction conduit 47.

The embodiment of FIGS. 5 and 6 has the advantage that the cutout 42 can be constructed to have such a length as to have a throttling effect on the medium flowing into pressure conduit 51, depending on the position of piston 37. Such a small throttle effect obtains a better filling and a less noisy operation of the pump at high loads. The particular construction of the groove 41 with slanted end faces obtains a guidance of the stream of the medium from filling conduit 48 into suction conduit 47 without great losses.

An additional advantage of this embodiment resides in that the angular position of the throttle opening 40 can be varied whereby different operational characteristics of the pump can be obtained, for example, the graph on the right of the point a in the diagram of FIG. 9 can be made to rise at a steeper angle than the first part of the graph or to drop or to extend in horizontal direction.

The embodiment of FIG. 8 corresponds in every respect to the embodiments of FIGS. 5 and 6, except that the valve piston is modified. For the sake of simplicity, the pressure conduit 51, which actually has the same position as described with reference to FIGS. 5 and 6, is shown in a position displaced about the axis of the valve piston 37'. Piston 37 is mounted in the bore 36 for axial movement and is biased by spring 45. An inner conduit communicating with chamber 46 is connected by a throttle opening 40 with a slot 55, which is connected by an elongated groove 56 with the chamber 460. Port of pressure conduit 51 cooperates with groove 56. The axial direction of the throttle opening 40' is the same as the axial direction of pressure conduit 51 so that the medium flows directly into pressure conduit 51, whereas in the construction of FIGS. 5 and 6, a stream of medium is turned twice about right angles between pressure chamber 46 and pressure conduit 51.

The arrangement of FIG. 8 permits it to compensate errors in regulation by varying the speed at which the medium flows out of throttle 40'. The static pressure variation of this stream by the increased flow speed, is transmitted by the elongated groove 56 into chamber 46a. Groove 56, whose longitudinal axis is perpendicular to the direction of the stream of the medium also dampens the valve piston 37' and can be made narrow enough to serve as a throttle. The slot 55 can be omitted.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of apparatus comprising a prime mover, a driven pump, and a hydraulic motor operated by the medium pumped by the pump, differing from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for filling the suction chamber of a displacement pump at high-pumping speeds, by producing an injector effect in the suction conduit of the pump, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

We claim:

1. Apparatus for filling the suction chamber of a pump at high-pump speeds, comprising, in' combination, a pump having pressure conduit means including first and second pressure conduits for supplying a pumped medium to a consumer means, a suction chamber, and suction conduit means connecting said suction chamber with the consumer means and including a suction conduit connected with said suction chamber, and a filling conduit; and biased valve means having a normal position connecting said first and second pressure conduits, and a regulating position for connecting said first pressure conduit also with said suction conduit, said valve means being responsive to a predetermined pressure of the medium in said first pressure conduit obtained at a predetermined speed of said pump, to move to said regulating position whereby a part of the pumped medium bypasses the consumer means and creates suction in said suction conduit, said valve means including a valve bore having adjacent suction and filling ports at the ends of said suction and filling conduits, and a valve piston movable relative to said valve bore between said normal and regulating positions and having a portion formed with a single peripheral groove extending over said suction and filling ports in both said positions of said valve means for establishing communication between said filling conduit and said suction conduit in both said positions so that an amount of the medium is sucked by said suction conduit from said filling conduit and flows into said suction chamber completely filling the same.

2. Apparatus as claimed in claim 1 wherein said suction means include a container receiving the pumped medium from the consumer means; and wherein said filling conduit is connected with said container so that the same supplies an amount of the medium for filling said suction chamber.

3. Apparatus as claimed in claim 1 wherein said pump includes a body formed with said valve bore, and also formed with said first and second pressure conduits, and with said suction conduit and filling conduits; and wherein said filling conduit, said suction conduit, and said valve bore are located substantially at right angles to one another.

4. Apparatus as claimed in claim 3 wherein said valve piston has an axis and is mounted in said valve bore nonrotatably and movable in axial direction; and wherein said groove has such a depth in radial direction of said valve piston that said axis of the same passes through said groove.

5. Apparatus as claimed in claim 1 wherein said pump in cludes a body formed with said valve bore, and also formed with said first and second pressure conduits, and with said suction and filling conduits; and wherein said suction and filling conduits are slanted to each other and to said valve bore and are located in the same plane.

6. Apparatus as claimed in claim 5 wherein said groove extends along said valve bore and has slanted lateral faces so that said groove is shorter at its bottom than at the outer surface of said valve portion; and wherein said suction and filling parts form a common port opening into said valve bore and communicating with said groove.

7. Apparatus as claimed in claim 1 wherein said valve means includes a spring abutting one end of said piston biassing the same to said normal position; wherein said valve bore includes a first pressure chamber at said one end and a second pressure chamber at the other end of said piston communicating with said first pressure conduit; wherein said second pressure conduit communicates with said first pressure chamber; comprising throttle means between said first pressure chamber and said second pressure chamber so that the pressure in said first pressure chamber is at said predetermined pressure and speed so much lower than in said second pressure chamber that said piston is moved to said regulating position for forming a gap connecting said second pressure chamber and first pressure conduit directly with said suction conduit.

8. Apparatus as claimed in claim 7 wherein said valve means has a wall formed with a throttle opening constituting said throttle means.

9. Apparatus as claimed in claim 7 wherein said valve means include a closure member closing said valve bore at said other end and forming said second pressure chamber, and also forming an outlet chamber communicating with said second pressure conduit, and also communicating with said first pressure chamber through said throttle means; and wherein said throttle means is a throttle opening formed in said closure member.

10. Apparatus as claimed in claim 7 wherein said piston forms an inner conduit connecting said first and second pressure chambers, and has a wall with an opening connecting the outer surface of said piston with said inner conduit; and wherein said second pressure conduit has a port in said valve bore located on said opening.

11. Apparatus as claimed in claim 7 wherein said throttle means is a cup-shaped member secured to said other end of said piston located in said second pressure chamber and having a throttle openin and wherein said piston has an inner conduit connecting t e interior of said cup-shaped member with said first pressure chamber.

12. Apparatus as claimed in claim 11 wherein said piston is formed with an other throttle opening connecting said inner conduit with said first pressure chamber.

Claims

1. Apparatus for filling the suction chamber of a pump at highpump speeds, comprising, in combination, a pump having pressure conduit means including first and second pressure conduits for supplying a pumped medium to a consumer means, a suction chamber, and suction conduit means connecting said suction chamber with the consumer means and including a suction conduit connected with said suction chamber, and a filling conduit; and biased valve means having a normal position connecting said first and second pressure conduits, and a regulating position for connecting said first pressure conduit also with said suction conduit, said valve means being responsive to a predetermined pressure of the medium in said first pressure conduit obtained at a predetermined speed of said pump, to move to said regulating position whereby a part of the pumped medium bypasses the consumer means and creates suction in said suction conduit, said valve means including a valve bore having adjacent suction and filling ports at the ends of said suction and filling conduits, and a valve piston movable relative to said valve bore between said normal and regulating positions and having a portion formed with a single peripheral groove extending over said suction and filling ports in both said positions of said valve means for establishing communication between said filling conduit and said suction conduit in both said positions so that an amount of the medium is sucked by said suction conduit from said filling conduit and flows into said suction chamber completely filling the same.

5. Apparatus as claimed in claim 1 wherein said pump includes a body formed with said valve bore, and also formeD with said first and second pressure conduits, and with said suction and filling conduits; and wherein said suction and filling conduits are slanted to each other and to said valve bore and are located in the same plane.

11. Apparatus as claimed in claim 7 wherein said throttle means is a cup-shaped member secured to said other end of said piston located in said second pressure chamber and having a throttle opening; and wherein said piston has an inner conduit connecting the interior of said cup-shaped member with said first pressure chamber.