US3279390A

US3279390A - Fluid translating device

Info

Publication number: US3279390A
Application number: US359311A
Authority: US
Inventors: Horlacher Herman
Original assignee: Cincinnati Milling Machine Co
Current assignee: Milacron Inc
Priority date: 1964-04-13
Filing date: 1964-04-13
Publication date: 1966-10-18
Anticipated expiration: 1983-10-18

Description

Oct. 18, 1966 Filed April 13, 1964 H. HORLACHE'R 3,279,390

FLUID TRANSLATING DEVICE 5 Sheets-Sheet l v LL.

INVENTOR.

HERMAN HORLACHEF ATTORNEYS Oct. 18, 1966 H. HORLACHER 3,279,390

FLUID TRANSLATING DEVICE Filed April 13, 1964 5 Sheets-Sheet .2

Fig.3

JJTY J7)"/,F7 I I 26a Q 14 1a Fig.2

Oct. 18, 1966 H. HORLACHER FLUID TRANSLATING DEVICE 5 Sheets-Sheet 3 Filed April 13, 1964 United States Patent 3,279,390 FLUID TRANSLATING DEVICE Herman Horlacher, Cincinnati, Ohio, assignor to The Cincinnati Milling Machine Co., Cincinnati, Ohio, a corporation of Ohio Filed Apr. 13, 1964, Ser. No. 359,311 2 Claims. (Cl. 103-162) The present invention relates to a fluid translating device and, more particularly, to such a device having pintle porting.

In one type of fluid translating device, such as a hydraulic pump, a rotor having a plurality of cylinders therein is driven for rotation on a stationary pintle. The cylinders slidably receive plungers which are reciprocated by engagement with a stationary, but tilted, member such as a swash plate. The pintle has two fluid passages, a low pressure passage extending between an opening in the pintle and an inlet port (which is connected to a reservoir), and a high pressure passage extending between a second opening in the pintle and an outlet port (which is connected to a pressure line). Fluid is taken into each cylinder from the low pressure passage as the plunger therein moves in one direction and is delivered under pressure to the high pressure passage by movement of the plunger in the opposite direction.

Each cylinder is in communication with the high pressure passage for almost half a revolution of the rotor and in communication with the low pressure passage for almost half a revolution of the rotor. This results in a sudden change from high pressure to low pressure in each cylinder once each revolution which contributes significantly to the noise of the pump. In order to reduce the noise arising from sudden decompression of each cylinder, it is known to provide a restricted decompression passage through which a small amount of high pressure fluid can leak from each cylinder before the cylinder comes into full communication with the low pressure passage. However, it has been found that under diflerent conditions, different amounts of decompression are desirable for optimum results. For example, generally, the greater the output pressure of the pump, the greater the amount of decompression needed. In short, a fixed amount of decompression is, at best, a compromise.

To improve the eflectiveness of the decompression of the cylinders, there is provided, in the present invention, a pintle which can be adjusted with respect to the rotor to increase or decrease the decompression from the cylinders. It is therefore one object of the present invention to provide for selective decompression of the cylinders.

Another factor contributing to the noise of the pump is the timing thereof. The timing of the hydraulic pump can be defined as the relationship between the reciprocating movement of each plunger and the movement of the opening to the cylinder for said plunger from the low pressure pintle passage to the high pressure pintle passage. In general, no particular relationship is best under all conditions. For example, at higher motor speed, each cylinder should leave the high pressure passage and encounter the low pressure passage sooner (with respect to the stroke of the plunger) than at lower speeds. In other words, any fixed relationship between reciprocation of the plungers and connection of the openings to the high and low pressure passages is, at best, a compromise.

To minimize noise due to timing under all conditions of operation of the pump, adjustment of the pintle relative to the rotor for optimum setting can be effected. It is therefore another object of the present invention to provide mechanism for adjustment of timing of the pump.

Means is provided to eflect axial adjustment of the pintle with respect to the rotor to adjust the decompression of the pump; and means is provided to effect rotary ad- 3,3939% Patented Get. 18, 1966 justment of the pintle with respect to the member producing reciprocation of the plungers to adjust the timing of the pump. It is another object of the present invention to provide separate means, operable independently of each other, for adjustment of the pintle.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification, considered in conjunction with the accompanying drawings forming a part thereof, and it is to be understood that any modifications may be made in the exact structural details there shown and described, within the scope of the appended claims, without departing from or exceeding the spirit of the invention.

In the drawings:

FIG. 1 is a side view, in cross section, of a hydraulic pump incorporating the present invention;

FIGS. 2, 3, 4, S, and 6 are views taken on the lines 22, 3-3, 44, 55, and 66, of FIG. 1, respectively.

There is shown in FIG. 1 a hydraulic pump having a housing 9 comprising a body portion 10, an end plate 11 connected to one end of the body 10, and a block 12 connected to the opposite end thereof. A stator, or pintle, 13 extends through block 12 and into the internal bore 14 of a rotor 15. The rotor, which is mounted in bearings 16 and 17 secured inside the housing, is rotated on axis A through a drive shaft 18 which is in splined engagement therewith. The drive shaft 18 is received in bearings 19 secured in end plate 11 for rotation on axis A, which is the central axis of the pintle, and extends outside the housing for connection to a motor (not shown).

The rotor has a plurality of cylinders 20, each cylinder extending from an annular face 21 on the rotor to a bore 22. Each cylinder 20 is inclined with respect to axis A and each bore 22 is perpendicular to the longitudinal axis B of the cylinder. Each bore 22 is closed at its outer end and terminates, at its inner end, at the internal rotor bore 14 to define a cylinder port.

The pintle 13 consists of a sleeve 25 having a core member 26 received therein. The core member, which has end discs 26a and 26b connected by a central wall, or web, 26c, defines with the sleeve 25 two

separate fluid passages

27 and 28 extending through the pintle. At the inner end of the pintle, and in registration with cylinder ports 22, the sleeve 25 has two

openings

29 and 30 each extending around the sleeve less than degrees, as shown best in FIG. 2. The

openings

29 and 30, through which

passages

27 and 28 are alternately connected to each cylinder port 22 as the rotor rotates, are separated by two

lands

31 and 32 180 degrees apart, each of a span S (circumferentially with respect to sleeve 25) substantially equal to or slightly greater (for example, up to ten percent greater) than the span, or diameter, of cylinder port 22. At the outer end, the pintle sleeve 25 has two

other openings

33, 34, as shown in FIG. 4 (similar to openings 29 and 30), for fluid connection of the outer end of

passages

27 and 28 to inlet port 35 and outlet port 36, respectively.

Each cylinder 20 has a plunger 40 slidably received therein which has a spherical head 41. A shoe 42 is pivotally received on each plunger head and each shoe is urged against an annular face 43 of swash plate 44 by :a spring 45 received between rotor 15 and a collar 46 on cylinder 20. llwo trunnions 47, extending from the swash plate 180 degrees apart are journaled in the housing on axis C, so that the swash plate can be pivoted about axis C by a rod 48 which extends from the swash plate through slot 49 in the housing. When the swash plate is perpendicular to axis A (that is, with annular face 43 everywhere spaced the same distance from rotor 15) none of the plungers 40 reciprocate in the cylinders as the rotor rotates. When the swash plate is tilted, however,

so that face 43 is at different distances from the rotor around the swash plate, the cylinders reciprocate in sequential order, each plunger completing a cycle on each rotation of the rotor and each plunger reaching the extreme inner limit of its stroke approximately when the cylinder port 22 passes from communication with opening 30 to communication with opening 29.

As shown in FIG. 1, in operation of the pump, the swash plate is tilted, for example, so that the upper side of face 43 is more remote from rotor 15 than the lower side thereof. Rotor 15 is rotated clockwise (when viewed from the left end of FIG. 1) as shown by arrow D so that as each cylinder 20 moves from the lowermost position to the uppermost position, the plunger therein moves outwardly in the cylinder, drawing fluid through inlet port 35 (as indicated by arrow E), through suction passage 27 (as indicated by arrow F), and through opening 29. As each cylinder 20 moves from the uppermost position to the lowermost position, the plunger moves in- Wardly in the cylinder pushing the fluid in the cylinder under pressure through opening 30, through passage 28 (as indicated by arrow G), and out outlet port 36 (as indicated by arrow H).

As the cylinder ports 22 sweep across land 32 from pressure opening 30 to suction opening 29, the sudden decompression in the successive cylinders generates a loud noise which can be best softened by a decompression groove which makes the decompression of cylinders 22 more gradual.

There is no rate of decompression which will be most effective in reducing pump noise. Instead, the most efiective amount of decompression will depend on several factors including, for example, the pressure at which the pump delivers fluid to the pressure line. There is provided on the pintle 13 a decompression groove 50, as shown in FIG. 5, having a leg 50a extending from groove 29 parallel to axis A, a leg 50b extending from the end of leg 50a toward axis A, and a leg 50c extending back from the end of leg 50b and parallel to axis A. It will be noted from FIG. that leg 50c terminates on land 32. The precise point at which leg 50c terminates with respect to the path of the cylinder ports 22 as they sweep past land 32 depends on the precise axial position of pintle 13 with respect to the rotor. Hence, the extent of the limited exposure of ports 22 to opening 29 (and therefore the extent of decompression of cylinders 20) through groove 50 (before direct communication of port 22 with opening 29) is determined by the axial position of the rotor. A groove (not shown) similar to groove 50 extends from opening 30 to land 31 to reduce noise stemming from the application of pressure to the cylinders as the cylinder ports sweep from the low pressure passage to the high pressure passage. The pintle 13 has a bar 51 connected to the end outside the housing by screws 52. Two

screws

53, 54 received in the bar, one 53 threadedly received in end block 12 and the other 54 engaged with end block 12, permit precise axial adjustment of pintle 13 with respect to end block 12 (and hence with respect to rotor Improper timing (that is, a less than optimum relationship between the reciprocation of each plunger and the change in communication of the corresponding cylinder port from one pintle passage to the other) will increase the noise of the pump. Proper timing; for one set of conditions will not be best for another set of conditions (as, for example, two difierent pump speeds) so, with fixed timing, a compromise must be made. However, in the pump disclosed herein, the timing can be adjusted to meet a variety of operating conditions. It will be noted that swash plate 44, although tiltable about axis C, cannot be rotated about axis A. However, the pintle 13 can be rotated a small amount about axis A so that the relationship between the reciprocation of the plungers and the change of each cylinder port from one pintle passage to the other pintle passage can be adjusted. A yoke 55 is connected to end block 12 to straddle the bar 51. Two set screws 56, 57 are threadedly received in the yoke to engage opposite sides of bar 51. It will be noted screw 53 is received in an elongated hole 58 in bar 51 so that when screw 53 is loosened, bar 51 can be angularly adjusted by set screws 56, 57. Thus pintle 13 can be angularly adjusted with respect to the swash plate 44 to adjust the timing of the pump.

What is claimed is:

1. In a hydraulic device:

(a) a rotor having a plurality of cylinders therein, each cylinder having a cylinder port in communication therewith,

(b) a pintle received in the rotor and having a pair of fluid passages therein terminating at openings, said openings having lands therebetween, said pintle having a groove terminating at one of said openings, said groove having a portion extending axially into and terminating on one of said lands for communication with said cylinder ports,

(0) a plunger received in each cylinder for reciprocation therein in timed relation to rotation of the rotor, each plunger drawing fluid from one pintle passage opening and delivering fluid to the other pintle passage opening,

(d) and means to effect relative axial adjustment between the pintle and the rotor to modify the extent of communication of the cylinder ports with said axially extending portion of said groove.

2. A hydraulic pump comprising:

(a) a housing,

(b) a rotor mounted in the housing, said rotor having a plurality of cylinders therein each having a cylinder port in communication therewith,

(c) a pintle received in the rotor, said pintle having a pair of fluid passages therein terminating at openings in the path of said cylinder ports, said pintle having lands between said openings and having grooves each with one end connected to one of said openings, each of said grooves having a portion extending axially into and terminating on one of said lands,

(d) a plunger in each cylinder,

(e) a swash plate tiltably mounted in the housing to reciprocate the plungers,

(f) means to effect relative axial adjustment between the pintle and the rotor to modify the extent of communication of the cylinder ports with said axially extending portions of said grooves as said ports cross the lands,

(g) and means to angularly adjust said pintle relative to said swash plate.

References Cited by the Examiner UNITED STATES PATENTS 1,925,378 9/1933 Ferris et al. l03l62 2,054,110 9/1936 Worth 103--161 2,529,309 11/1950 Purcell 103-461 2,936,716 5/1960 Looker 103120 3,187,681 6/1965 Firth et al c 103-161 MARK NEWMAN, Primary Examiner.

SAMUEL LEVINE, Examiner.

R. M. VARGO, Assistant Examiner.

Claims

1. IN A HYDRAULIC DEVICE: (A) A ROTOR HAVING A PLURALITY OF CYLINDERS THEREIN, EACH CYLINDER HAVING A CYLINDER PORT IN COMMUNICATION THEREWITH, (B) A PINTLE RECEIVED IN THE ROTOR AND HAVING A PAIR OF FLUID PASSAGES THEREIN TERMINATING AT OPENINGS, SAID OPENINGS HAVING LANDS THEREBETWEEN, SAID PINTLE HAVING A GROOVE TERMINATING AT ONE OF SAID OPENINGS, SAID GROOVE HAVING A PORTION EXTENDING AXIALLY INTO AND TERMINATING ON ONE OF SAID LANDS FOR COMMUNICATION WITH SAID CYLINDER PORTS, (C) A PLUNGER RECEIVED IN EACH CYLINDER FOR RECIPROCATION THEREIN IN TIMED RELATION TO ROTATION OF THE ROTOR, EACH PLUNGER DRAWING FLUID FROM ONE PINTLE PASSAGE OPENING AND DELIVERING FLUID TO THE OTHER PINTLE PASSAGE OPENING, (D) AND MEANS TO EFFECT RELATIVE AXIAL ADJUSTMENT BETWEEN THE PINTLE AND THE ROTOR TO MODIFY THE EXTENT OF COMMUNICATION OF THE CYLINDER PORTS WITH SAID AXIALLY EXTENDING PORTION OF SAID GROOVE.