US3885444A

US3885444A - Barrel mechanism for a piston pump

Info

Publication number: US3885444A
Application number: US413895A
Authority: US
Inventors: Gerard Chanlon
Original assignee: Creusot Loire SA
Current assignee: Creusot Loire SA
Priority date: 1972-12-14
Filing date: 1973-11-08
Publication date: 1975-05-27
Anticipated expiration: 1992-05-27
Also published as: DE2355648B2; NL7315923A; NO140355C; DE2355648C3; DK137396B; JPS5743743B2; NL174754B; GB1421053A; ATA1029573A; DK137396C; LU68984A1; CH572158A5; AT331640B; SU470124A3; DE2355648A1; CA987171A; JPS505902A; SE392952B; FR2211090A5; BE808576A

Abstract

A barrel mechanism comprises, with a casing, a rotatable shaft mounted in two bearings supported respectively by two ends of the casing perpendicular to the axis of the shaft, and to which is fixed a plate oblique with respect to the axis, a barrel bearing on the oblique plate, centred about an axis, intersecting the axis of the shaft, on an inclined cylindrical bearing on the shaft and perpendicular to the plate, and a means locking the barrel against rotation, wherein the two ends of the casing are connected by a tie-rod extending along the axis of the shaft in an axial bore in the shaft.

Description

United States Patent [191 Chanlon [451 May 27, 1975 BARREL MECHANISM FOR A PISTON PUMP [75] Inventor: Gerard Chanlon, Le Creusot,

[30] Foreign Application Priority Data Dec. 14, 1972 France 72.44532 [52] U.S. Cl. 74/60 [51] Int. Cl. Fl6h 23/08; Fl5h 23/10 [58] Field of Search 91/499; 74/60; 417/269 [56] References Cited UNITED STATES PATENTS 2,095,316 10/1937 Davis, Jr. 74/60 2,150,162 3/1939 l-lau 74/60 2,387,908 10/1945 Howard 74/60 2,498,679 2/1950 Hall 74/60 2,926,735 3/1960 Cook 74/60 FOREIGN PATENTS OR APPLICATIONS 1,175,467 3/1959 France.... 74/60 799,828 4/1936 France ..74/60 Primary ExaminerWilliam L. Freeh Attorney, Agent, or Firm-Cameron, Kerkam, Sutton, Stowell & Stowell [5 7] ABSTRACT A barrel mechanism comprises, with a casing, a rotatable shaft mounted in two bearings supported respectively by two ends of the casing perpendicular to the axis of the shaft, and to which is fixed a plate oblique with respect to the axis, a barrel bearing on the 0blique plate, centred about an axis, intersecting the axis of the shaft, on an inclined cylindrical bearing on the shaft and perpendicular to the plate, and a means locking the barrel against rotation, wherein the two ends of the casing are connected by a tie-rod extending along the axis of the shaft in an axial bore in the shaft.

8 Claims, 2 Drawing Figures PATENTEDMAYQ? ms sum .mm mm Nm mm SHEET PATENTEU MAY 27 1975 BARREL MECHANISM FOR A PISTON PUMP The object of the invention is a barrel mechanism applicable particularly to axial-piston pumps.

A known pump of this type comprises a pump body having a number of pistons distributed round an axis and each displaceable in a cylinder parallel with the axis, and a mechanism forming a rotor driven by a motor and having an oblique thrust-face actuating the pistons by rotation about the axis.

In small pumps the oblique thrust-face is a simple circular plate located in a plane oblique with respect to the axis of rotation and upon which the pistons bear directly by means of rods provided with spherical bearing faces.

In larger pumps, however, it is preferable to connect the pistons to the oblique thrust face by connecting rods. In such a case a barrel mechanism is employed which comprises, inside a casing, a driving shaft rotated about its axis in two bearings supported respectively by two ends of the casing perpendicular to the axis and to which is fixed a plate extending obliquely with respect to the axis of the shaft, and a barrel bearing on the oblique plate and centered about a point on the axis of the shaft on an inclined cylindrical bearing on the shaft and perpendicular to the plate. In addition the barrel is prevented from rotating by some means locking it against rotation. Each piston is connected to the barrel by a connecting-rod articulated to the piston and to the barrel at a point remote from the axis.

It is clear that because the barrel is prevented from rotating, rotation of the shaft causes an oscillation of the barrel about its centre, the axis of the barrel, which coincides with that of the inclined cylindrical bearing, describing a cone about the axis of the shaft. This oscillatory motion controls the movement to and fro of the pistons.

Barrel mechanisms are employed for pumps of medium power, but when it is required to produce pumps of high power and high pressure crankshaft pumps are generally employed. The disadvantage of these is that they are heavy and bulky.

Barrel mechanisms on the other hand enable a much more rational arrangement since the motor; the rotor and the body of the pump can be in line. However, the large forces to be withstood by the barrel and transmitted to the casing have hitherto prevented the production of high power pumps, particularly if it is desired to limit their bulk and their weight.

According to the invention there is provided a barrel 3 mechanism comprising, inside a casing, a rotatable shaft mounted in two bearings supported respectively by two ends of the casing perpendicular to the axis of the shaft, and to which is fixed a plate oblique with respect to the axis, a barrel bearing on the oblique plate, centred about an axis intersecting the axis of the shaft, on an inclined cylindrical bearing on the shaft and perpendicular to the plate, and a means locking the barrel against rotation, wherein the two ends of the casing are connected by a tie-rod extending along the axis of the shaft in an axial bore in the shaft.

Preferably the tie-rod is prestressed before the mechanism is put into service.

The invention will be more fully understood from the following description of embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a longitudinal section of a first embodiment according to the invention; and

FIG. 2 is a longitudinal section of a second embodiment according to the invention.

The mechanism shown in FIG. 1 comprises a casing 1 comprising a cylindrical wall 10 to which are fixed two

parallel ends

11 and 12. Inside the casing 1 is located a hollow shaft 2 rotatably mounted at one end, by a plain ring 21, on a tubular distance-piece 3 arranged on the axis 20 of the casing and bearing against the two

ends

11 and 12 of the casing.

A tie-rod 4 extending within the tubular distancepiece 3 connects the two ends of the casing against which it bears by means of a head 42 and a nut 41 enabling the tie-rod 4 to be kept. under a certain tensional prestress taken up by the distance-piece 3.

The end 12 of the casing is attached to a pump body (not shown) comprising a plurality of axial pistons distributed round the axis of revolution 20. Each piston is connected to a slide 5 moving parallel with the axis in a cylinder 51 fixed to the end 12 of the casing.

The shaft 2 bears against the other end 11 of the casing by means of a thrust-plate 22 integral with the shaft 2, by means of a plain thrust-face 23.

The shaft 2 is driven by the motor (not shown) located adjacent the end 11, by means of a reducer comprising an input pinion 6 meshing with a wheel 24 fixed to the plate 22. The inner face of the wheel 24 advantageously constitutes the second journal for the shaft 2, bearing by means of a plain ring 25 against a cylindrical bearing integral with the end 11.

The shaft 2 also bears a plate 26 inclined with respect to the axis of revolution and a cylindrical bearing 27 perpendicular to the said plate, the axis 270 of which is inclined to the axis of revolution of shaft 2.

A barrel 7 is centred on the cylindrical bearing 27 by means of a plain ring 71 and bears against the plate 26 by means of a plain thrust-face 72. The barrel 7 is prevented from turning by any means, for example, by a connecting-rod (not shown) articulated to the casing and the lower portion 73 of the barrel.

The barrel is connected at its periphery to the slides 5 by means of connecting-rods 8, by ball-and-socket joints, the ends of the connecting-rods constituting the male portions 81 of the ball-and-socket joints, the female portions 82 of which are attached to the barrel 7, at a point remote from the axis of rotation, and to the slide 5 respectively.

When the shaft 2 is rotated by the pinion 6 and the wheel 24, the axis 270 of the cylindrical bearing 27 describes a cone about the axis of revolution 20 and the result is that the barrel 7, being locked in rotation oscillates about the point of intersection between the

axes

20 and 270.

This oscillatory motion of the barrel is transformed by the connecting-rods 8 into a to -andfro movement of the slides 5 transmitted directly to the pistons of the pump. For a pump of high power the forces withstood by the barrel are very large. Thus for a pump of 1,000 HP a thrust of tons on the barrel must be reckoned on. This thrust is taken up by the oblique plate 26 and transmitted directly through ribs 28 to the thrust-plate 22 which bears against the end 11 of the casing.

However, the tie-rod 4 has been previously prestressed to a tension greater than this thrust of 130 tons, the prestress being taken up at no load by the distance-piece 3. The result is that the thrust exerted by the slide on the barrel is transmitted to both ends of the casing and taken up wholly by the tie-rod 4 without extension of the latter and consequently without deformation of the casing. The casing, and in particular its sidewall 13, which withstands practically no force, can therefore be considerably lightened. It will be observed, moreover, that the employment of a hollow shaft enables the latter to bear against the distancepiece by means of an internal bearing and hence the length of the shaft to be substantially reduced. Another reduction in the length is obtained by the arrangement of the other bearing of the shaft on the inner face of the wheel 24 of the reducer.

Finally the employment of plain rings and thrustfaces likewise enables a reduction in bulk and weight of the whole. These rings will, for example, be of bronze or bimetal selected as a function of the forces to be withstood.

The space between the two

plates

22 and 26 enables shaft balance-weights to be easily located, enabling rotation without risk of vibration to be obtained.

The employment of the prestressed connecting tierod between the ends of the casing enable considerable lightening of the latter. That is, taking into account the magnitude of the thrusts at high power, a conventional casing would have had to be very rigid and very heavy. By taking up the forces without risk of deformation, the tie-rod enables an extremely light casing to be produced which as shown in FIG. 1 can be composed of relatively thin sheet metal 13 provided with longitudinal stiffeners 14.

The employment of plain rings and thrust-faces as in FIG. 1, though it enables additional reduction in weight and bulk of the whole is not, however, indispensable.

Taking into account the working conditions, it may in fact be preferred to employ roller guide and thrust bearings as shown in the embodiments of FIG. 2, whilst keeping within the allowable limits of weight and bulk.

In this embodiment the barrel 7 is in fact centred by a roller bearing 710 and bears against the oblique plate 26 by means of a roller thrust-bearing 720. Having regard to the thickness of the thrust-bearing 720, it has been possible to bring the plate 26 to adjacent the plate 22 so that it is formed as one body with the plate 22, whilst leaving clearance for the end 73 of the barrel.

The plate 22 bears against the end 11 of the casing by means of a roller thrust-bearing 23 and the shaft 2 is provided with an extension rotating in an outer roller bearing 250 fixed to the end 11. At the other end, however, the shaft2 bears against the distance-piece 3 by means of an internal roller bearing 210.

It can be seen that the use of roller guide and thrust bearings does not substantially affect the weight and bulk of the mechanism.

Of course the invention is not intended to be limited to the details of the two embodiments which have just been described. In particular the shapes of the shaft and the various parts could clearly be modified. The mechanism could be adapted for driving any kind of axial piston pump directly or by means of articulated connecting-rods as has been illustrated.

Finally such a mechanism can be adapted for use not only in a pump but in any means employing the displacement of axial pistons, such as a compressor or a piston engine, the mechanism then serving to transform the axial displacement of the pistons into rotation of the shaft.

What is claimed is:

l. A barrel mechanism comprising:

a. a rotatable shaft having an axial bore;

b. a casing within which said shaft extends and having ends perpendicular to the axis of said shaft;

c. bearings supported respectively by said casing ends and supporting said shaft;

d. a plate fixed to said shaft and extending obliquely with respect to said axis of said shaft;

e. a barrel bearing on said oblique plate, centred about an axis intersecting said axis of said shaft, on an inclined cylindrical bearing perpendicular to said plate;

f. means locking said barrel against rotation;

g. a prestressed tie-rod extending along the said axis of said shaft in said axial bore and connecting said casing ends to absorb axial thrust on said barrel, said oblique plate being integral with a thrust plate on that end of said casing remote from said barrel with respect to said oblique plate, said thrust plate being fixed to said shaft perpendicular to said axis of said shaft, said tie-rod extending in a tubular distance piece fixed to said two ends of said casing and extending through said axial bore in said shaft.

2. A barrel mechanism as claimed in claim 1, wherein said bearings of said shaft are internal bearings.

3. A barrel mechanism as claimed in claim 1, wherein at least one of said bearings of said shaft is an internal bearing by means of which said shaft rotates on said tubular distance piece.

4. A barrel mechanism as claimed in claim 1, wherein said tie rod is prestressed to a tension which is at least equal to the axial resultant of the maximum forces to be transmitted by said barrel to said thrust plate.

5. A barrel mechanism as claimed in claim 1, wherein said bearings of said shaft are plain bearings.

6. A barrel mechanism as claimed in claim 1, wherein a plain ring is interposed between said barrel and said inclined cylindrical bearing.

7. A barrel mechanism as claimed in claim 1, wherein thrust faces are interposed between said barrel and said oblique plate and between said thrust plate and said end of said casing.

8. A pump comprising axial pistons and a barrel mechanism as claimed in claim 1 constituting the rotor of the pump, each piston being connected to a respective barrel by a connecting rod articulated to said piston and to said barrel at a point remote from said axis of said shaft.

Claims

1. A barrel mechanism comprising: a. a rotatable shaft having an axial bore; b. a casing within which said shaft extends and having ends perpendicular to the axis of said shaft; c. bearings supported respectively by said casing ends and supporting said shaft; d. a plate fixed to said shaft and extending obliquely with respect to said axis of said shaft; e. a barrel bearing on said oblique plate, centred about an axis intersecting said axis of said shaft, on aN inclined cylindrical bearing perpendicular to said plate; f. means locking said barrel against rotation; g. a prestressed tie-rod extending along the said axis of said shaft in said axial bore and connecting said casing ends to absorb axial thrust on said barrel, said oblique plate being integral with a thrust plate on that end of said casing remote from said barrel with respect to said oblique plate, said thrust plate being fixed to said shaft perpendicular to said axis of said shaft, said tie-rod extending in a tubular distance piece fixed to said two ends of said casing and extending through said axial bore in said shaft.