US2749843A

US2749843A - Control valve for a hydraulic apparatus

Info

Publication number: US2749843A
Application number: US449304A
Authority: US
Inventors: Nubling Otto
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-08-13
Filing date: 1954-08-12
Publication date: 1956-06-12
Anticipated expiration: 1973-06-12

Description

June 12, 1956 o. NUBLING 2,749,843

CONTROL VALVE FOR A HYDRAULIC APPARATUS f Filed Aug. 12, 1954 4 Sheets-Sheet l A F m U E '0 Z I" ll 0 0 N N H 9 l ll l I June 12, 1956 UB 1 2,749,843

CONTROL VALVE FOR A HYDRAULIC APPARATUS Filed Aug. 12, 1954 4 Sheets-Sheet 2 24 n b I4 a 20 June 12, 1956 o. NUBLING 2,749,843

CONTROL VALVE FOR A HYDRAULIC APPARATUS Filed Aug. 12, 1954 4 Sheets-Sheet 3 June 12, 1956 o. NUBLING ,7

CONTROL VALVE FOR A HYDRAULIC APPARATUS Filed Aug. 12, 1954 4 Sheets-Sheet 4 United States Patent C CQNTROL VALVE FOR A HYDRAULIC APPARATUS Otto Niibling, Weener (Ems), Landsburg, Germany Application August 12, 1954, Serial No. 449,364

Claims priority, application Germany August 13, 1953 Claims. (Cl. 103-41) The present invention relates to a control valve for hydraulic gear pumps and engines, and more particularly to a control valve provided with a passage preventing excessive pressure in a chamber covered by the sealing face of the control valve.

It is an object of the present invention to provide a control valve for hydraulic gear pumps and engines which permits adjustment of the output of the hydraulic apparatus.

It is another object of the present invention to provide a channel in a control valve for a gear pump by which excessive pressure in a chamber of the gear pump covered by a sealing face of the control valve is prevented.

It is a further object of the present invention to provide a sealing face of the control valve having an increased width whereby undesired communication between pressure and discharge side of the gear pump is prevented in intermediate positions of the control valve.

The present control valve is to be applied to a hydraulic apparatus substantially described in my Patent No. 2,688,927, dated September 14, 1954, and my Patent No. 2,694,288, dated November 16, 1954.

The hydraulic apparatus as particularly described in the said first mentioned patent comprises a casing, a hollow inner member rotatably mounted in the casing and having teeth on its perimeter defining a plurality of depressed portions thereon, the hollow inner member having an inner chamber bounded by a cylindrical surface and being formed with a plurality of radially extending conduits connecting each of the depressed portions with the inner chamber in the hollow inner member and forming slots in the inner cylindrical surface, and an annular outer member rotatably mounted in the casing eccentrically with respect to the hollow inner member and surrounding the same, the outer annular member having a plurality of inner teeth defining depressed portions on its inner surface and meshing with the teeth on the hollow inner member whereby the depressed portions of the inner and outer members form chambers successively increasing in volume on one side of the hollow inner member and decreasing in volume on the other side of the hollow inner member during each revolution and in combination therewith a tubular control valve, turnably mounted in the casing extending into the inner chamber in the hollow inner member tightly fitting therein turnably with respect to the same between two positions normal to each other, the tubular control valve including an inner transversal wall located in the region of the conduits and dividing the interior of the tubular control valve into two tubular sections, each tubular section formed with an opening in the region of the conduits for supplying and discharging, respectively, a liquid to the conduits, the inner transversal Wall having diametrically arranged free edge portions extending substantially parallel to the axis of the tubular control valve and provided with diametrically located sealing faces flush with the outer surface of the tubular control valve, separating the openings in the two tubular sections and permanently Patented June 12, 1956 abutting against the cylindrical inner surface of the hollow inner member in the region of the conduits, the sealing faces adapted to cover opposite slots formed in the inner cylindrical surface by opposite conduits, the transversal wall being formed with an internal channel terminating in the sealing faces and adapted to establish communication between two opposite chambers, the internal channel forming in the sealing faces narrow slots extending in axial direction of the hollow inner member for substantially the same distances as the slots formed by the conduits in the inner cylindrical surface of the hollow inner member so as to permit liquid to flow from a chamber decreasing in volume to an opposite chamber increasing in volume while the sealing faces of the transversal wall cover the conduits corresponding to the last-mentioned chambers whereby excessive pressure in the last-mentioned chamber decreasing in volume is prevented.

Excessive pressure in a chamber decreasing in size whose corresponding conduit is covered by a sealing face is prevented by the internal channel which permits a communication of the closed pressure chamber with the opposite suction chamber.

With these and other objects in view which will become apparent in the following detailed specification, the present invention will be clearly understood by reference to the accompanying drawings, in which:

Figure 1 shows in longitudinal section a regulable hydraulic apparatus according to the present invention e. g. a pump with toothed wheels arranged one in the other.

Figs. 2 to 6 are cross sections according to line A-B of Fig. l at different positions of the toothed wheels.

Referring now to the drawings, the hydraulic apparatus working as a pump comprises essentially an outer member 6 with internal teeth 6 and a meshing inner member 2 with external teeth 2. The outer member 6 possesses one tooth more than the inner member 2. The outer member 6 rests freely rotatably in the bearings 7 and 8 of the casing 5 which encloses the gear. The inner member 2 is formed as a cylindrical hollow body which rests in the bearings 3 and 4 and has on the one side a shaft end portion 1 to which driving means may be connected. The two

members

2 and 6 are mounted eccentrically with respect to each other and meshing. The distance of the axis of the two wheels is denoted with E (Fig. 2).

In the interior of the cylindrical hollow body of the inner member 2 is arranged a tubular control valve 11. It may be regulated by turning a lever 12 mounted thereon. The control valve 11 is divided by a wall into an inlet chamber 13 and an outlet chamber 17. From the inlet conduit 9 a liquid may enter into the inlet chamber 13 through the ports 10 provided in the cylindrical hollow body, whilst the discharge of the liquid from the outlet chamber 1'7 of the control valve 11 takes place through the ports 18 into the outlet conduit 19.

The inner member 2 has conduits 14 or 16 traversing it radially from the interior to the outer surface. Through these conduits liquid may flow from or to the control valve 11. The liquid flowing from the interior of the control valve 11 to the exterior of the member 2 enters the Working chambers 15 which are defined between the inner and

outer members

2 and 6.

In Figs. 2 to 6 different positions of the control valve 11 are shown in relation to the

members

2 and 6. During the rotation of the

members

2 and 6 in the direction of the arrow (Figs. 2 to 6), the chambers 20 defined between two opposite teeth increase on one side whilst the chambers 21 defined between the teeth of the two members decrease on the other side. Therefore, the suction chambers 20 draw liquid through the conduits 14 3. whilst within the pressure chambers 21 liquid flows out through the conduits 16. The quantity of liquid pressed out from the chamber 22 corresponds with the quantity of liquid sucked into the chamber 23 (Fig. 2). Accordingly only the chambers 24 feed liquid into the outlet chamber 17 and outlet pipe 19. The quantity of liquid pressed out from the chamber 25 corresponds with the quantity of liquid sucked into the chamber 26. Correspondingly only the chamber 27 sucks fluid from the interior of the control valve 11. According to the turning of the control valve 11 the quantity of liquid sucked off changes.

In accordance with the present invention, the controlling sealing face namely the part of the control valve 11, which engages directly the interior surface of the inner member 2 and is bounded by controlling sealing faces, is wider on the pressure-side than on the suction side.

In Fig. 2 the controlling sealing face of the control valve 11 in direction to the pressure-side is smaller for the distance a than the width b of the

conduits

14 or 16. This means, that the conduit 28 (Fig. 3) will never be completely closed during the rotation of the member 2 from the position shown in Fig. 2 to that shown in Fig. 3.

In the position shown in Fig. 3 the transversal channel 29 in the wall of the rotatory valve 11 is opened for the distance a, when the controlling sealing face 31 disposed in the rear of the direction of rotation just closes the conduit 28. This arrangement brings about that in the diminishing chamber 31 an intolerable over-pressure can never arise. During further rotating movement the liquid pressed out from the chamber 31 is fed through the transversal channel 29 into the chamber 32, thereby preventing the formation of a vacuum in the chamber 32.

In the position shown in Fig. 4 the

members

2 and 6 are still further moved. On the suction side the width of the sealing face is exactly the same as the width b of the conduit 35. In this case the chamber 15 is completely closed. Yet the formation of a vacuum in the chamber 15 is not possible because the liquid pressed out from the chamber 31 is fed through the transversal channel 29 into the chamber 15. Therefore, in accordance with the invention, the distance d of engagement between the sealing face of the rear end of the dividing wall of the control valve 11 and the inner face of the inner member 2 corresponds with the width of the transversal channel 2 minus the distance a.

Fig. shows the further course of the controlling process performed by the control valve 11. The diminishing pressure chamber 31 presses liquid during rotation of the members from the position shown in Fig. 4 to the position shown in Fig. 5 through the transversal channel 29 into the suction chamber 15. Since the conduit 33 gets into communication during this movement with the pressure-side 34 of the control valve 11 the chamber will be at least partly filled with liquid.

During the further rotation of the

members

2 and 6 to the position shown in Fig. 6 of the controlling sealing face of the control valve 11 disposed in front of the direction of rotation opens the diminishing pressure chamber 31 to the outlet chamber 17 of the control valve 11, so that the liquid pressed out from the chamber 31 is fed to the outlet chamber 17 on the suction side. Simultaneously the transversal channel 29 is gradually closed to the side of the enlarging suction chamber. It may be seen, that the distance 1 in Fig. 4 corresponds with the distance g of the transversal channel 29 from the conduit 35 minus the distance a.

By arrangement of the sealing faces of the control valve 11 in accordance with the distances set forth above, an inadmissible rise of the pressure in the pressure chamher and the formation of a vacuum in the suction chamber is at all times avoided. During rotation of the

members

2 and 6 from the position shown in Fig. 2 to that .4 shown in Fig. 3 and from the position shown in Fig. 5 to that shown in Fig. 6 a communication between the suction-side and the pressure side in the pump is brought about, which is equal to null in the position shown in Fig. 2, continually increases up to the maximal value of a/ 2 and decreases to null in the position shown in Fig. 3. The direct communication between the suction-side and the pressure-side is, however, of no damaging effect in fast running pumps, because the moment of inertia of the liquid prevents the flow of a nominal quantity of fluid from the pressure-side to the suction-side.

The manner of using and applying the embodiment of my invention set forth above will be clear from the foregoing description. It is, of course, to be understood that my invention is not limited to the specific embodiment thereof here shown and described for purposes of illustration only. Various changes and modifications may be made in the hydraulic apparatus set forth and in the structural details shown, without departing from the spirit of this invention.

While I have disclosed one embodiment of the present invention, it is to be understood that this embodiment is given by example only and not in a limiting sense, the

scope of the present invention being determined by the objects and the claims.

I claim:

1. in a hydraulic apparatus including a casing, a hollow inner member rotatably mounted in said casing and having teeth on its perimeter defining a plurality of depressed portions thereon, said hollow inner member having an inner chamber bounded by a cylindrical surface and being formed with a plurality of radially extending conduits connecting each of said depressed portions with said inner chamber in said hollow inner member and forming slots in said inner cylindrical surface, and an annular outer member rotatably mounted in said casing eccentrically with respect to said hollow inner member and surrounding the same, said outer annular member having a plurality of inner teeth defining depressed portions on its inner surface and meshing with said teeth on said hollow inner member whereby said depressed portions of said inner and outer members form chambers successively increasing in volume on one side of said hollow inner member and decreasing in volume on the other side of said hollow inner member during each revolution, in combination, a tubular control valve turnably mounted in said casing extending into said inner chamber in said hollow inner member tightly fitting therein, said tubular control valve including an inner transversal well located in the region of said conduits and dividing said tubular control valve into two tubular sections, each tubular section formed with an opening in the region of said conduits for supplying and discharging, respectively, a liquid to said conduits, each opening extending for nearly half of the periphery of said tubular control valve opposite the opening in the other of said two tubular sections, said openings being located on opposite sides of said inner transversal wall, said inner transversal wall having diametrically arranged free edge portions extending substantially parallel to the axis of said tubular control valve and provided with diametrically located sealing faces flush with the outer surface of said tubular control valve, separating said openings in said two tubular sections and permanently abutting against said cylindrical inner surface of said hollow inner member in the region of said conduits, said sealing faces adapted to cover opposite conduits during rotation of said inner and outer members, said transversal well being formed with an internal channel terminating in said sealing faces and adapted to establish communication between a contracting and an expanding chamber when said sealing faces cover the conduits associated with said last mentioned chambers, one of the said sealing faces being located during turning of said tubular control valve on the side of said hollow inner member on which chambers of increasing volume are formed, and the other of said sealing faces being located during turning of said tubular control valve on the side of said hollow inner member on which chambers of decreasing volume are formed, said one of said sealing faces having substantially the same width as said slots formed in said cylindrical surface by said conduits, and said other of said sealing faces having a width greater than the width of said slots formed in said cylindrical surface by said conduits.

2. The hydraulic apparatus, as set forth in claim 1, in which said sealing face of greater width is enlarged over the width of said slots formed in said cylindrical surface by said conduits in the direction of rotation for a distance not larger than the distance of the forward edge of said internal channel of the transversal wall from the rear edge of the slot in said hollow inner mem' ber associated with the corresponding opposite sealing face having substantially the same width as said slots formed in said cylindrical surface by said conduits, in the position in which said slot on the side of said hollow inner member, on which chambers of increasing volume are formed, has just been closed.

3. The hydraulic apparatus, as set forth in claim 1, in which said sealing face of greater width is enlarged over the width of said slots formed in said cylindrical surface by said conduits in the direction opposite to that of rotation for a distance not larger than the distance of the rear edge of said internal channel of the transversal wall from the forward edge of said slot, formed in said cylindrical surface by said conduits, in direction of rotation on the side of said hollow inner member on which chambers of decreasing volume are formed, in the position in which said slot on the side of said hollow inner member, on which chambers of increasing volume are formed, has just been closed' 4. The hydraulic apparatus, as set forth in claim 1, in which said sealing face of greater width is enlarged over the width of said slots formed in said cylindrical surface by said conduits in the direction of rotation for a distance not larger than the distance of the forward edge of said internal channel of the transversal wall from the rear edge of the slot of said hollow inner member associated with the corresponding opposite sealing face having substantially the same width as said slots formed in said cylindrical surface by said conduits, in the position in which said slot on the side of said hollow inner member, on which chambers of increasing volume are formed, has just been closed, and in which said sealing face of greater width is enlarged over the Width of said slots formed in said cylindrical surface by said conduits in the direction opposite to that of rotation for a distance not larger than the distance of the rear edge of said internal channel of the transversal wall from the forward edge of said slot, formed in said cylindrical surface by said conduits, in direction of rotation on the side of said hollow inner member on which chambers of decreasing volume are formed, in the position in which said slot on the side of said hollow inner member, on which chambers of increasing volume are formed, has just been closed.

5. The hydraulic apparatus, as set forth in claim 1, in which the enlargements in and opposite to the direction of rotation, respectively, of the said sealing face on the side of the said hollow inner member on which chambers of decreasing volume are formed over the width of the said slots formed in said cylindrical surface by said conduits are equal to the distance of the forward edge of said internal channel of the transversal Wall from the rear face of the latter in the position in which said slot on the side of said hollow inner member, on which chambers of increasing volume are formed, has just been closed, and to the width of said internal channel taken in the direction of a plane perpendicularly to the rotating axis of said control valve, respectively, said last mentioned distance and said last mentioned width being shortened for an amount which is equal to the width of a slot formed between the rear edge of the said sealing face in direc tion of rotation on the side of said hollow inner member on which chambers of decreasing volume are formed and the rear edge of said slot formed in said cylindrical surface by said conduits, in the position in which the rear edge of the said internal channel coincides with the front edge of said slot formed in said cylindrical surface by said conduits, the said amount being dependent upon the number of revolutions of said inner and outer members.

References Cited in the file of this patent UNITED STATES PATENTS 1,341,846 Gollings June 1, 1920 2,011,338 Hill Aug. 13, 1935 2,140,966 Nichols Dec. 20, 1938 2,688,927 Nuebling Sept. 14, 1954 2,694,288 Nuebling Nov. 16, 1954 FOREIGN PATENTS 9,359 Great Britain of 1915