GB2128265A

GB2128265A - Pressurized fluid mechanism, motor or pump

Info

Publication number: GB2128265A
Application number: GB08324641A
Authority: GB
Inventors: Louis Bernard Bigo; Patrick Edmond Ramousse
Original assignee: Poclain Hydraulics France SA
Current assignee: Poclain Hydraulics France SA
Priority date: 1982-09-30
Filing date: 1983-09-14
Publication date: 1984-04-26
Also published as: GB8324641D0; DE3334016A1; FR2533965A1; BR8305190A; FR2533965B1; JPS5990780A; GB2128265B

Abstract

An hydraulic motor or pump comprises a casing 1, 2 a cylinder block 4 mounted for rotating with respect to said casing and comprising a face 19 for transferring the fluid to and from each cylinder and a fluid control valve 14 connected to a fluid admission and exhaust, which control valve is provided with a fluid distribution face 18 cooperating with the transfer face and wedged in rotation with respect to the frame by way of an immobilization device consisting of a slot formation integral with a first of the two elements - casing and control valve - and of a lug 31 integral with the second of said two elements and designed to be received in said slot. <IMAGE>

Description

SPECIFICATION Pressurized fluid mechanism, motor or pump With hydraulic motors and pumps, it is known that fluid has to be distributed periodically, internally to the mechanism, to the different cylinders, to allow admission and exhaust thereof.

To this effect, a fluid control valve fitted on the support with respect to which the cylinder-block is rotatably mounted. The means used for securing the control valve to said support is generally a lug added to one of these elements and inserted into a two-shanked fork secured to the other element.

A number of disadvantages have been found with this type of construction.

First of all, there is a possibility that the added lug becomes detached from the corresponding element, which would cause not only a breakdown in the mechanism, but also and most of all, grave damage.

Moreover, the overall dimensions, in particular radially, of the mounted assembly consisting of the lug and the fork, are large. What is a general disadvantage with all mechanisms becomes a major handicap with some of them, where radially positioned pistons can be kept in a "retracted" position inside the cylinders under the effect of return springs. Since one of the spring assembly extends substantially inside the same transverse plane as the assembly used to immobilize the control valve in rotation with respect to its support, provision should obviously be made to allow relative rotation of the two assemblies, and to this effect the radial space taken by the immobilizing assembly should be small enough to prevent all interference between these two assemblies when the pistons are retracted inside the cylinders.

And so it became necessary, in order to eliminate the risks of breakdowns and damages, and to allow certain mechanisms to work without their dimensions increasing, to find a more compact and more reliable design than that known up to now.

It is the object of the present invention to propose such a new design.

The invention therefore relates to a pressurized fluid mechanism, whether a pump or motor, which comprises a frame, a cylinder block, mounted for relative rotation on the frame, and inside which are fitted cylinders, and comprising a face for transferring fluid to and from each cylinder, and a fluid control valve, connected to a fluid admission and exhaust, which control valve comprises a fluid distribution face cooperating with said transfer face, and is wedged in rotation with respect to the frame by means of a device of immobilization in rotation comprising at least one holding assembly, whereas each holding assembly contains a housing integral with a first one of the two following elements on the mechanism-frame and fluid control valve-and a lug integral with the second of said two elements and designed to be received inside said housing.

In this mechanism, on the one hand, the housing is situated in the first element proper, and on the other hand, the lug is monobloc with the second element.

The following advantageous dispositions are also preferably adopted: -the lug is made in the second element by turning part of said element about the axis of relative rotation and by a double milling to remove the material of said second element symmetrically with respect to a diametral plane traversing the axis of relative rotation, and substantially perpendicular to said plane; -the fluid-transfer face of the cylinder block and the fluid-distributing face of the control valve being plane and perpendicular to the axis of relative rotation, each holding assembly is placed substantially close to the plane supporting both the fluid-transfer and -distribution faces.

The invention will be more readily understood on reading the following description with reference to the accompanying drawings, in which: Figure 1 is an axial section along I-I of Figure 2, of a motor according to the invention, according to a first working configuration, Figure 2 is a cross-section along Il-Il of Figure 1, of the same motor, in a second working configuration; and Figure 3 is a section along Ill-Ill of Figure 1.

The mechanism illustrated in the drawings is a hydraulic motor constituted by: -a case in two parts 1 and 2 assembled by way of screws 3, -a cylinder block 4 comprising a bore with grooves 5, -an output shaft 6, one end of which is provided with grooves 7 cooperating with the grooves 5 of the cylinder block, which shaft is mounted for rotating with respect to the case 1-2 by means of taper bearings 8, about a geometrical axis 9, -a cam 10 constituting the central inner periphery of the case 1-2, cylinders 11, extending radially with respect to the rotation axis 9 and angularly distributed at regular intervals, pistons 1 2 mounted for sliding in the cylinders, one in each cylinder, whose opposite ends at the bottom of the cylinders support runners 13 via which they can rest on the cam 10, -a fluid control valve 14, which is contained inside a housing 1 5 provided in the case 1 2, with which it cooperates to form two annular grooves 16 and 1 7 separated from the other, which control valve comprises a distribution face 18, which is plane, transversal and perpendicular to the axis 9, and which rests against a plane face 19 of the cylinder block 4, also perpendicular to axis 9.

The following dispositions have to be observed: the bottom of every cylinder 11 communicates with the plane face 1 9 of the cylinder block via a conduit 20; the groove 16 communicates with the distribution face 18 via conduits 21; the groove 1 7 communicates with the distribution face 18 via conduits 22; the orifices through which conduits 21 and 22 issue into the distribution face 1 8 are centered on a circle 23, which circle is centered on the rotation axis 9, and the orifices through which the conduits 20 issue on to the plane face 1 9 are centered on a circle which is centered on said rotation axis 9;; each runner 13 is traversed by an axial rod 24 extending out of each side of the runner, a return spring 25 having its ends 25a attached to the ends of the rods 24 situated on the same side of the cylinder-block 4; the springs 25 situated on the side of the control valve 14 are all traversed by a transverse plane 26 which is perpendicular to the axis of rotation 9, and in fact constitutes the plane of section Il-Il, and which is adjacent to the plane of faces 1 8 and 19; the grooves 16 and 1 7 are connected via conduits 27 and 28 internal to the case, to the outside of the case, and to pressurized fluid supply 29 and to a non-pressurized (or very low-pressurized) fluid exhaust 30:: control valve 14 can move slightly in parallel to axis 9 until the pressures exerted on the fluid contained inside grooves 1 6 and 17 bring the distribution face 18 against the plane face 19 of the cylinder block 4; said control-valve 14, on the other hand, comprises two diametrically opposite lugs 31, which extend radially whilst being traversed first by the transverse plane 26 and second by a diametral plane 35 which is the plane of section I-I, each of which planes are situated between the two shanks 32 of a fork equipping the case 1-2, said control valve 14 being thus immobilized in rotation with respect to said case 1-2 (and to the cam 10 provided therein);; the lugs 31 are machined in the block of material constituting the control valve 14, and are thus monobloc therewith, and inseparable therefrom; they are made first by turning, about rotation axis 9, from the end 33 of the control valve adjacent the distribution face 18, and then by a double milling 34 of translation axis parallel to axis 9, thus forming two faces 31 a on the lug, which faces are parallel to the diametral plane 35 and situated at equal distance of said plane;; -the shanks 32 of a fork form part of a border 36 which is integral with the part 2 of the case, and extends in parallel to axis 9 in the direction of the cylinder block 4, and said shanks are machined in said border 36, each one being defined by a face 32a parallel to the diametral plane 35, the two parallel faces 32a being apart one from the other so as to receive a lug 31 between them by being situated opposite one of the faces 31 a of said lug, and this without virtually any play between the lug 31 and the two shanks 32.

According to a variant, the shanks 32 of a fork could be part of, or monobloc with control valve 14 and, complementarily, the lugs 31 would then be part of and monobloc with the case 1-2. Said lugs 31 could also extend axially instead of radially, the shanks being themselves extendable radially instead of axially.

Also to be noted in the illustrated embodiment is the fact that the external periphery 36a of the border 36 is substantially contained inside the extending portions of cylinder constituted by the turned face 33 of the control valve.

The dispositions described hereinabove have the following advantages.

First of all the lugs 31, like the shanks 32 of the corresponding forks, are monobloc with and inseparable from the elements of which they form part, this making it impossible for said lugs and shanks to become accidentaliy and undesirably separated from their respective support.

Moreover, the coinciding of external peripheries 36a of borders 36 (and shanks 32) with the cylinder of face 33 defining the radial extension of each lug 31 considerably improves the radial dimensions of the assembly by reducing these to a minimum. This enables, in a motor with radial pistons 12 adapted to be returned to a retracted position inside their cylinders 11, by springs 25 (Figure 2), to produce effectively this particular design without the spring interfering with the cylindrical face 33 and with the lugs 31, and this despite the fact that, in order to reduce the axial dimensions of the motor to a minimum, said springs 25 and lugs 31 have been placed inside the same transverse plane 26. Particularly reduced overall dimensions, whether axially or radially, are thus obtained even in those cases where springs 25 are provided. Such reduction is important in a motor of which the runners 13 are already partly contained inside the pistons 12 precisely to reduce the overall dimensions radially.

It should also be noted that the control valve 14 is immobilized (31-32) with respect to the case 1-2 in the immediate vicinity of the support plane of the distribution face 1 8 on the plane face 1 9 of the cylinder block 4. The immobilizing torque thus acts in the same zone as the friction forces torque generated between faces 1 8 and 19, this again constituting the best soiution.

Finally, the last advantage to be noted is the easy way in which the lugs for example are produced, by a simple turning (33) followed by equally simple millings 34.

The invention is in no way limited to the description given hereinabove and on the contrary covers all variants that can be made thereto without departing from its scope or its spirit.

Claims

1. Pressurized fluid mechanism, motor or pump, comprising: a frame, a cylinder block, mounted for relative rotation on the frame, and inside which are fitted cylinders, and comprising a face for transferring fluid to and from each cylinder, and a fluid control valve, connected to a fluid admission and exhaust, which control valve comprises a fluid distribution face cooperating with said transfer face, and is wedged in rotation with respect to the frame by means of a device of immobilization in rotation comprising at least one holding assembly, whereas each holding assembly contains a housing integral with a first one of the two following elements on the mechanism-frame and fluid control valve-and a lug integral with the second of said two elements and designed to be received inside said housing, mechanism wherein said housing is situated in the first element proper, and the lug is monobloc with the second element.

2. Mechanism according to claim 1, wherein said lug is made in the second element by turning part of said element about the axis of relative rotation and by a double milling to remove the material of said second element symmetrically with respect to a diametral plane traversing the axis of relative rotation, and substantially perpendicular to said plane.

3. Mechanism according to claim 1, wherein, in known manner, the fluid-transfer face of the cylinder block and the fluid-distributing face of the control valve being plane and perpendicular to the axis of relative rotation, whereas each holding assembly is placed substantially close to the plane supporting both the fluid-transfer and -distribution faces.

4. Mechanism substantially as hereinbefore described with reference to, and as illustrated in the accompanying drawings.