US3803985A - Devices for retaining the sliding shoes of barrel pumps and motors - Google Patents

Devices for retaining the sliding shoes of barrel pumps and motors Download PDF

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Publication number
US3803985A
US3803985A US00151450A US15145071A US3803985A US 3803985 A US3803985 A US 3803985A US 00151450 A US00151450 A US 00151450A US 15145071 A US15145071 A US 15145071A US 3803985 A US3803985 A US 3803985A
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United States
Prior art keywords
shoes
plate
barrel
washer
hydrostatic
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US00151450A
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English (en)
Inventor
R Maistrelli
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Renault SA
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Renault SA
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Publication date
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0044—Component parts, details, e.g. valves, sealings, lubrication
    • F01B3/007—Swash plate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0082—Details
    • F01B3/0085—Pistons
    • F01B3/0088—Piston shoe retaining means

Definitions

  • the present invention relates in general to oleohydraulic pumps and motors of the barrel-cylinder type, wherein the pistons are reciprocated in a direction parallel to the axis of the pump or motor. This reciprocating motion is controlled by an impeller or swash plate on which the piston heads are caused to slide, these piston heads being generally provided to this end with socalled hydrostatic sliding shoes.
  • each piston is accelerated during the delivery stroke, then accelerated again but in the reverse direction and also decelerated in this reverse direction during the suction phase.
  • delivery stroke deceleration, and during the suction strokeacceleration
  • This retaining plate has formed therein a recess for a dished washer urged by a spring tensioned or prestressed between the washer and the bottom of said re cess, so that this spring also assists in pressing the cylinder barrel against the distributor plate.
  • the sum of the efforts due to the kinetic energy or vis inertia of the different pistons and shoes produces a torque tending to increase the inclination of the retaining plate in relation to the barrel axis.
  • the corresponding reaction torque can be provided only by an eccentric reaction of the swash plate which is balanced by a prestressed spring housed in the barrel.
  • the aforesaid spring must therefore have dimensions sufficient to compensate this reaction in case the pump were caused to rotate at high speed under zero load conditions. Since this spring also urges the barrel against the distributor plate, the sliding contact surfaces of the barrel and/or distributor plate are most likely to be damaged when the pump is operated under these conditions.
  • the device according to this invention is intended for retaining the pistons and sliding shoes of pumps and motors of the above-defined type against the surface of the swash or impeller plate by means of a connecting device of the type permitting the adjustment and taking up of play through aresilient member.
  • This invention is also directed to an elastic coupling member adapted to exert on the shoes moderate retaining forces at low speeds and relatively considerable retaining forces at high speeds.
  • this invention provides a shoe retaining device permitting the separate adjustment of the force urging the cylinder barrel against the distributor plate.
  • the device according to this invention which comprises a bearing member formed with peripheral recesses and adapted to press the shoes against an inclined flat surface in conjunction with the thrust exerted by a part-spherical washer responsive to the action of a resilient member, is characterized in that said resilient member is mounted in a prestressed condition between a bearingsurface formed on the pump driving shaft and the part-spherical washer, and that the permissible flexion of said resilient member is adjustable in a manner known per se by means of a device for adjusting the op- I crating clearance between the hydrostatic shoes and said inclined flat surface.
  • FIG. 1 is a sectional view of a pump, the section being taken along the line I'I of FIG. 2;
  • FIG. 2 is an end view of the pump barrel
  • FIG. 3 is a fragmentary sectional view of the pump, taken along the line IIIIII of FIG. 2;
  • FIG. 4 is a plane view of the pump shoes bearing member
  • FIG. 5 is a section taken along the line VV of FIG. 4;-
  • FIG. 6 is an orthogonal projection on the impeller or swash plate of the rotational axis of the cylinder barrel and of the path of the point of intersection of the axis of rotation of the shoe on the plate surface;
  • FIG. 7 is a sectional view showing a hydrostatic shoe on a larger scale.
  • FIGS. 8 and 9 are two axial sectional views showing two modified forms of embodiment of pumps according to this invention.
  • the hydrostatic shoes 1 are connected to the relevant pistons 2 by means of partspherical ball members 3 retained by a circlip.
  • hydrostatic shoes 1 are adapted to slide on the registering surface of a rotary plate 4 bearing in turn against the swash or impeller plate 5.
  • This plate 5 comprises hydraulic bearings 6 corresponding in shape to the hydraulic bearings 7 provided between the cylinder barrel 8 and the distributor plate 9.
  • a hearing member 10 contacting the face 11 of said hydrostatic shoes 1 is formed with recesses 12, shown more in detail in FIGS. 4 and 5, which permit the passage of the cylindrical necks 13 of said shoes.
  • the bearing member 10 comprises on the other hand a recess 14 having a partspherical surface centered to the axis of rotation of plate 4 and at least two centering studs 15.
  • This bearing member 10 is centered by means of its part-spherical surface 14 engaging a washer 16 bounded by a partspherical outer surface complementary to the surface 14 of member 10, and centered to the shaft 17 of the pump and in the plane of the centers of the partspherical or ball members 3 of the hydrostatic shoes.
  • the bearing member 10 engages one face of shaft 17 (shown in the form of its spline l8 connecting this shaft to cylinder barrel 8) through the medium of a resilient member such as an elastic washer l9 and a rigid washer 20.
  • the elastic washer 19 is adapted, from its unstressed condition, to be deflected by a few tenths of millimeter.
  • the centering and rotary coupling or rotary gaging the recesses 12 of this bearing member with a play sufficient to permit their relative movement during the operation of the device.
  • the projection on the swash plate 5 of the swivel ball of each shoe 1 describes during the operation of the device an ellipse e, at an angular speed on and an amplitude varying during the movement at a rotational speed mo of barrel 2 which is assumed to be constant.
  • the angular shift a between the projections, on swash plate 5, of the centers of two successive shoes 1 will also vary during a barrel revolution, so that the bearing plate 10 of which the recesses 12 are disposed at spaced angular intervals along its periphery is driven in succession by all the shoes 1 during one fraction of a revolution.
  • the centering studs 15 may consist of insert pieces.
  • the shaft 17 is mounted in this bearing by means of a compound rolling-contact bearing 22 comprising axial and radial rollers.
  • the mounting is obtained by using a nut 23 engaging a counter-plate 24.
  • the adjustment device comprising this nut 23 is tightened home, so that the resilient washer 19 is fully compressed and the parts inserted between the spline 18 of shaft 17 and the nut 23 are in successive direct engagement, i.e., without any play. Then the nut 23 is released by an angle such that its axial movement corresponds to the desired operating clearance for the aforesaid stacked parts, and the lock washer 25 is eventually bent to fix the desired adjustment position.
  • Another advantage resulting from this arrangement is that it minimizes the degree of overhang of the radial effort exerted on piston heads in the outermost position of these pistons in relation to their cylinders, this overhang being eliminated completely in the innermost position.
  • FIG. 7 illustrates another possibility of synchronizing and centering the rotary plate 4 in relation to the'hydrostatic shoes 1 by means of studs inserted in these shoes 1 and engaging corresponding recesses 27 formed in the rotary plate, with a play sufficient for permitting their relative movements during the pump operation; in fact, any point of the axis of each stud 15 describes an ellipse whereas the center of each recess 27 describes a circle as already explained hereinabove.
  • the studs 15 are hollow and comprise a slot 28 permitting the delivery of oil to the shoe bearing and to the impeller or swash plate bearings 6.
  • these studs 15 may as well be secured to the rotary plate 4, the operating play being provided in this case by a recess similar to recesses 27 but formed in the shoe.
  • the operating play adjustment nut 23 may be replaced by a circlip, the counterplate 24 being in this case selected among a series of gauged counterplates having different thicknesses, the choice of the proper plate 24 being subordinate to the measurement of the necessary play when assembling the parts.
  • the hydrostatic shoes -1 are in direct sliding contact with the swash plate 5, without any intermediate rotary plate.
  • no centering studs are provided on the bearing member 10. This arrangement is advantageous in-that it is considerably simpler but attended by a considerable speed in the relative sliding movements between shoe and plate; thus, the thrust, not hydrostatically, is relatively high especially when the angle of inclination of the swash plate is relatively great.
  • the swash plate 5 is rigid with the pump body or casing.
  • swash or impeller plates notably those adapted to pivot about pivot pins 30 of relatively small diameter, disposed on either side of the barrel and having their common axis disposed in the plate containing the centers of the partspherical ball members 3 of the hydrostatic shoes 1, this axis also passing through the center of the spherical surface of the part-spherical washer 16, as illustrated in FIG. 9.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
US00151450A 1970-07-07 1971-06-09 Devices for retaining the sliding shoes of barrel pumps and motors Expired - Lifetime US3803985A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7025147A FR2097453A5 (enExample) 1970-07-07 1970-07-07

Publications (1)

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US3803985A true US3803985A (en) 1974-04-16

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US00151450A Expired - Lifetime US3803985A (en) 1970-07-07 1971-06-09 Devices for retaining the sliding shoes of barrel pumps and motors

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US (1) US3803985A (enExample)
FR (1) FR2097453A5 (enExample)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4516475A (en) * 1977-07-02 1985-05-14 Robert Bosch Gmbh Hydrostatic piston machine
US20180142553A1 (en) * 2016-11-24 2018-05-24 Danfoss Power Solutions Gmbh & Co. Ohg Hydraulic axial piston unit with central fixed hold down device
US10920757B2 (en) * 2018-07-12 2021-02-16 Kobe Steel, Ltd. Liquid pressure rotary machine

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1710567A (en) * 1926-10-14 1929-04-23 John Robson Hydraulic pump, motor, brake, transmission gear, and the like
US2953099A (en) * 1957-06-13 1960-09-20 New York Air Brake Co Pump
US3173376A (en) * 1957-03-21 1965-03-16 United Systems Corp Hydraulic pump or motor
US3274897A (en) * 1963-12-23 1966-09-27 Sundstrand Corp Piston return mechanism
US3292553A (en) * 1963-12-30 1966-12-20 Sunstrand Corp Piston return mechanism
US3543649A (en) * 1968-08-19 1970-12-01 Cessna Aircraft Co Axial piston pump or motor device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1710567A (en) * 1926-10-14 1929-04-23 John Robson Hydraulic pump, motor, brake, transmission gear, and the like
US3173376A (en) * 1957-03-21 1965-03-16 United Systems Corp Hydraulic pump or motor
US2953099A (en) * 1957-06-13 1960-09-20 New York Air Brake Co Pump
US3274897A (en) * 1963-12-23 1966-09-27 Sundstrand Corp Piston return mechanism
US3292553A (en) * 1963-12-30 1966-12-20 Sunstrand Corp Piston return mechanism
US3543649A (en) * 1968-08-19 1970-12-01 Cessna Aircraft Co Axial piston pump or motor device

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4516475A (en) * 1977-07-02 1985-05-14 Robert Bosch Gmbh Hydrostatic piston machine
US20180142553A1 (en) * 2016-11-24 2018-05-24 Danfoss Power Solutions Gmbh & Co. Ohg Hydraulic axial piston unit with central fixed hold down device
US10662773B2 (en) * 2016-11-24 2020-05-26 Danfoss Power Solutions G.m.b.H. & Co. OHG Hydraulic axial piston unit with central fixed hold down device
US10920757B2 (en) * 2018-07-12 2021-02-16 Kobe Steel, Ltd. Liquid pressure rotary machine

Also Published As

Publication number Publication date
FR2097453A5 (enExample) 1972-03-03

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