US3813187A

US3813187A - Vane-type hydraulic pump

Info

Publication number: US3813187A
Application number: US00353228A
Authority: US
Inventors: K Winter
Original assignee: Deutsche ITT Industries GmbH
Current assignee: TDK Micronas GmbH; ITT Inc
Priority date: 1972-04-21
Filing date: 1973-04-23
Publication date: 1974-05-28
Anticipated expiration: 1991-05-28
Also published as: DE2219587A1

Abstract

A vane-type hydraulic pump is disclosed which employs a variable working chamber. It employs a by-pass regulator formed to include a flow-control valve and a pilot pressure relief valve which are formed as part of the pump shaft, thereby providing a reduction in pump size and weight.

Description

United States Patent [1 1 V Winter May 28, 1974 1 1 VAN E-TYPE HYDRAULIC PUMP [56] References Cited [75] Inventor: Klaus Winter, Ju1ius-Brecht-Str., UNITED STATES PATENTS Germany 2,899,941 8/1959 Adams 417/310 x [73] Assignee: International Telephone a 3,415,194 12/1968 Connelly 417/310 X Telegraph Industries, Inc., New York, NY. Primary ExaminerCarl1on R. Croyle Assistant ExaminerRichard Sher [22] 1973 Attorney, Agent, or Firm-l B. Raden; D. P. Warner [21] Appl. No.2 353,228

, [57] ABSTRACT [30] Foreign Application Priority Data A vane-type hydraulic pump is disclosed which em- Apr. 21, 1972 Germany 2219587 ploys a variable, jworking chamber It e lo a b I pass regulator formed to include a flow-control valve Cl 1 and a pilot pressure relief valve which are formed as [51] Int. Cl. F04b 23/12, F04b 39100 t f the pump shaft, thereby providing a reduction [58] Field 01' Search; 417/310, 284, 87, 302, in pump size and weight,

2 Claims, 2 Drawing Figures r l VANE-TYPE HYDRAULIC PUMP BACKGROUND OF THE INVENTION 1. Fieldof the Invention This invention relates to a vane-type hydraulic pump. An exemplary pump includes a rotor provided with radially movable vanes which, together with the rotor, bilaterally disposed side plates, a cam disc and a working chamber, enclose a continuously changeing volume when the rotor is driven. By-pass regulation is provided in an exemplary pump by the combination of a flow control valve and a pressure relief valve formed as part of the pump drive shaft portion of the rotor.

2. Description of the Prior Art Previously known vane-type pumps have been controlled by means of a by-pass regulator. In the known embodiments, the valve has been placed either in the housing member or in the pump housing cover with the disadvantage that special ducts and bores have had to be provided in the housing, resulting in relatively large overall dimensions for such pumps.

SUMMARY OF THE INVENTION It is the object of the present invention to provide an efficient vane-type hydraulic pump of particularly light weight and small dimensions. Furthermore, the pressure-medium connectors should be arranged independently of the position of the by-pass valve.

In accordance with the present invention, this is achieved in that there is provided in a concentric bore in the pump shaft, a flow-control valve of the conventional type communicating with a pilot pressure-relief valve, said pump shaft being preferably provided with radial ducts constituting the inlet and outletducts for the valves. In order to increase pump efficiency,an annular collar is provided spaced. from the pump shaft and embracing it concentrically, one .of the ducts opening out to the annular po'rt area through which pressure medium is flowing out.

BRIEF DESCRIPTION OF THE DRAWINGS This invention allows for a large variety of embodiments. One embodiment will be described with reference to the attached drawing in which:

FIG. 1 is a longitudinal view of the hydraulic pump; and

FIG. 2 is a cross-sectional view of the pumpon the lines A-B according to FIG. I.

In essence, the pump includes the pump housing 1 comprising the suction port 2 and the pressure port 3; the pump shaft 4 supported in the housing I and comprising the rotor 5 and the vanes 43 (radially movable lamellae); the stationary cam disc 6; the bilaterally disposed side plates 7, 8; and the housing cover 9 tightly sealing the pump housing 1.

The pump shaft 4 is provided with a blind bore 10 closed by means of a disc 1 I and containing a piston 13 which is movable in longitudinal direction against the force of a pressure spring 12. The blind bore 10 also contains a pressure-relief valve indicated generally by numeral 14. In addition, a plurality of radially extending ducts have been provided in the pump shaft 4, thus connecting the longitudinal bore 10 with the working chambers filled with pressure medium and arranged radially outwardly. Said ducts are: Duct 15 connecting the chamber behind the pressure-relief valve 14 with the ring duct 16 for lubricating the pump-shaft bearing 17; the radial bore 18 connecting the chamber between piston 13 and relief valve 14, via duct 32 in the side plate 7, to the pressure-sided ring chamber 19; the radial duct 20 connecting the pocket 21 in the side plate 8 with the blind bore 22 of piston 13; and finally the radial duct 23 connecting the blind bore 10 of the pump shaft 4 with the ringchamber 24 disposed between the side plate 8 and the sheet-metal collar 35.

When the pump shaft 4 is driven, the pressure medium to be supplied will be sucked in via the suction port 2, therefrom flowing to chamber 25 provided between the housing cover 9 and the end of the pump shaft 4 or the sheet-metal collar 35, respectively, and further through the space between stud 26 and pump shaft 4 into ring chamber 24 until it reaches the working chambers 28 of rotor 5 via an axially extending duct '27. Flow is then directed to pocket 28a and, through duct 38, to ring chamber 19 from which the pressure medium will be supplied to pressure port 3.

If a determined pressure has been built up in the ring chamber 19 or in the pockets 28a and 21 respectively, the discharge-pressurized medium flows also from pocket 21 through the

ducts

29, 20 and 30 to the blind bore 22 of piston 13, inducing said piston to move against the force of spring 12 in the direction of the arrow until piston 13 has reached a position enabling part. of the supplied pressure medium to flow back to the ring chamber 24 through the radial duct 23. Duct 23 being comparatively narrow, the pressure medium passes the sheet-

metal collar

35, 26 at high speed, thus generating a pump effect in the area of the annular port 40 for the benefit of the suction flow.

If an undesirably high pressure has been built up at the pressure port 3 for the pressure line or in ring chamber 19 respectively, the pressure head will also affect the pressure-relief valve 14 (the space between piston l3 and valve .14) through the radially extending ducts 32 and 18. Under the influence of the pressure,

the ball 33 moves in opening direction, i.e. leftward, thus opening the passage towards duct 15 or ring duct 16 respectively. From ring duct 16 the pressure medium is allowed to flow back through duct 34 to the suction-side of ring chamber 41.

The vane-type hydraulic pump described above includes both a flow-

control valve

13, 30 and a pilot pressure-relief valve 14. Both valves are concentrically disposed in the pump shaft.

The injection effect within the area of the annular port 40 has proved to be particularly useful in that its specially designed sheet-

metal collar

35, 26, in connection with the radial duct 23, serves as an aid to improve pump performance. The guide for the bypass spring 12 is coated with suitable plastics material (e.g. PTFE) to minimize the influence of friction in the event of buckling, e.g. due to centrifugal forces occurring at high rotational speed.

While the principles of the invention have been described above in connection with specific apparatus and applications, it is to be understood that this de-. scription is made only by way of example and not as a limitation on the scope of the invention.

I claim:

1. A vane-type hydraulic pump; comprising means forming a working chamber of continuously changing volume when a rotor is driven; said means including a rotor formed about a pump shaft, radially movable vanes, bilaterally disposed side plates, and a cam disc; 2. In a pump as claimed in claim 1, an annular collar a concentric bore in the pump shaft; and aflow-control spaced from the pump shaft and forming an annular valve and a pilot pressure-relief valve located within port area around said shaft, and one of the outlet ducts said bore; said pump shaft including radial ducts constiopening out to the annular port area.

tuting inlet and outlet ducts for each of said valves. 5

Claims

1. A vane-type hydraulic pump; comprising means forming a working chamber of continuously changing volume when a rotor is driven; said means including a rotor formed about a pump shaft, radially movable vanes, bilaterally disposed side plates, and a cam disc; a concentric bore in the pump shaft; and a flow-control valve and a pilot pressure-relief valve located within said bore; said pump shaft including radial ducts constituting inlet and outlet ducts for each of said valves.

2. In a pump as claimed in claim 1, an annular collar spaced from the pump shaft and forming an annular port area around said shaft, and one of the outlet ducts opening out to the annular port area.