FR2613781A1 - DISPENSER FOR A HYDROSTATIC PISTON MACHINE - Google Patents

Abstract

A) DISTRIBUTOR FOR A HYDROSTATIC PISTON MACHINE; B) CHARACTERIZED IN THAT THE ANGLE (PH) INCLUDED BETWEEN AREA 14 DELIMITATING (ENDING) THE OBLONG DISTRIBUTOR 7 DISTRIBUTION ORIFICE 11, AT ITS PRIMITIVE CIRCLE 15, AND ARETE 16 DELIMITATING (BEGINNING) THE OBLONG ASPIRATION ORIFICE 10, AT ITS PRIMITIVE CIRCLE 15, WHEN OBSERVED IN THE DIRECTION OF ROTATION OF THE CYLINDRICAL BODY IS SHAPED FROM AN ANGLE OF BEAN PHB AND AN ANGLE OF EXPANSION PH WHICH IS OBTAINED ACCORDING TO THE FORMULA: (CF DRAWING IN BOPI) C) THE INVENTION RELATES TO A DISTRIBUTOR FOR A SELF-PRIMING HYDROSTATIC PISTON MACHINE.

Description

"Dispenser for a hydrostatic piston machine".

  The invention relates to a dispenser for a self-priming hydrostatic piston machine which operates with a rotating cylindrical body carrying driving pistons and which has two oblong distribution ports for supplying and discharging the working fluid. who is

face.

  This distributor finds its application in

  self-priming hydrostatic piston machines,

  pump or motor and which are shaped into

  radial or axial piston, constant displacement or

  riable. According to the document DD-PS 43.563, an axial piston pump is known whose barrel dispensing orifices stop the connection with the oblong suction orifice, when the suction stroke of the pistons stops and which must

  traverse a distribution rib making an angle of overlap

  to connect with the oblong hole

  LEMENT. The discharge stroke that is introduced here causes a balancing of the pressures between the orifice of

  distribution in the barrel and the oblong outlet orifice.

  A similar angular shift occurs on the

  distribution rib which is located opposite, between the

  elongated discharge and the oblong suction port.

  This solution allows to adjust only the dependence of

  known compression and expansion angles and the possibilities

  partial compensation of variable dead spaces in

  the case of devices with variable displacement. In this realization

  tion, a determination of an expansion angle is also

  necessary to achieve the object of the present invention.

  According to DE-OS 2.208.B90, is also

  It is well known that an axial piston pump with a

  whose oblong holes are arranged in such a way that the distribution openings which are located on the side of the

  rotor are connected to the oblong port of vehicle

  low pressure, as long as we have not exceeded 50 to

  20: the bottom dead center of each piston.

  The connection of the flow channels with the o-

  distribution area located on the discharge side, at the point where

  higher death, leads to significant internal losses.

  Even with a throttling, unobstructed expansion of the volume under stress, in the dispensing orifice located on the side

  low pressure results in the appearance of the

  of air leading to cavitation, as well as

vibrations in the system.

  The goal is to find the value of use

  hydrostatic piston machines by stabilizing the function

  by increasing the lifespan and decreasing the repor-

environment.

  The object of the invention is to obtain a reduction

  effective noise generation in hydrostatic piston machines

  light distribution, constant displacement and variable

  able, by optimizing the distribution part, in order to improve the behavior of the suction and

decrease cavitation.

  According to the present invention, the problem is solved in that the angle 'f Ges, between the edge delimiting (ending) the oblong orifice of the dispenser, to its pitch circle, and the edge delimiting (starting) the oblong suction orifice, at the pitch circle, when observed in the direction of rotation of the cylindrical body, is formed by a bean angle fB and an expansion angle fEx which is obtained according to the formula: cos' Ex = 1 - Pb max VT *

r0. FK to tgo.

  this depends on: - The maximum operating pressure (Pb max) - The dead space (VT) - The turning angle (o <) of the motion transmitter (for devices with variable displacement) - From the Compressibility index () of the working fluid - Primitive piston circle radius (ro0) - Piston surface (FK) with dead space depending on the turn angle and calculated as follows: (VTc) = dead space minimum for internal dead pint, in the case of fixed displacement apparatus, (VTV = VTC to (VTC + 0.5, FK, tg max)

  in the case of variable displacement appliances.

  An example of embodiment of the invention is shown in the accompanying drawing, in which: - Figure 1 shows a partial longitudinal section through an axial piston machine and - Figure 2 shows a distriUuteur in a section according to

line A-A of FIG.

  A cylindrical body 1 represented in FIG.

  1 and belonging to an existing machine axial pistons, con-

  represented in a machine with fixed displacement, has pistons 5 which move in translation in their cylindrical bores 2, as a result of their support on the motion transmitter 4 and is supported with its distribution surface 6 on the distributor 7,

  which is rotatably connected to a dispensing head 8.

  Distribution holes 9 in the form of beans connect the cylindrical bores 2 to the surface of the

  6. Oblong outlets for suction and discharge

  10, 11, which are arranged in the distributor 7, are connected to the suction and discharge channels 12, 13 which

  located in the dispensing head. 8. The provision of the

  elongated suction port 10 and the oblong discharge port

  11 is done by considering the angle 'Ges. who is trained

  from the bean angle 'B and the expansion angle' Ex.

  This angle {Ges is limited by the edge 14 which terminates the oblong discharge orifice 11 to its pitch circle 15 and the edge 16 starting the oblong suction orifice 10 to the pitch circle, this seen in the direction of rotation the cylindrical body 1, obtaining the expansion angle is effected by the relationship: cos Ex = - Pb max 'VT *' r r * FK. tgq ro 'E and for a device with a constant displacement of qth = 100 cm3 / revolution: - a max. operating pressure Pb max = 40 MPa - A dead space VT = 17.2 cm - A compressibility index of the fluid of 1 / K (OK = 1.43 i03 MPa) - A pitch radius of a primitive circle r = 4, 5 cm - A piston surface FK = 3.8 cm (With a piston diameter of dK = 22mm) - A turn angle e = 18 - This gives an expansion angle according to: costEx = 1 - 40 - 17 2

 4E, 5. 3.8. 0.3249. 1.43. 1000

cos qEX = 0.913

E = 24

  In a development of the piston machine

  described above, as a displacement apparatus

  with variable strokes, we obtain the value of the dead space: VTV = VTC at (VTC + 0.5, FK, r, tg "max)

  = 17.2 to (17.2 + 0.5.3.8, 4.5, 0.3249)

  = 17.2 to 19.9 cm From which we consider the average value in the calculation of determin-

nation of YEx.

  Using the ei-forward determination for the expansion angle x, on the distributor 7 of self-priming piston machines, a minimum of noise is obtained for their entire pressure range, as well as a coefficient of

  improved filling, because it avoids a sudden relaxation of the

  dead space in the oblong suction hole 10 especially for

  high service pressures. It follows an im-

  performance at high service pressures, by following

  the exploitation of energy stored in dead spaces.

Claims (1)

R E V E N D I C A T IO N S   1) Distributor for a piston machine   self-priming hydrostatic, which works with a cy-   rotating horn, carrying driving pistons and having two oblong distribution ports for supplying and discharging the driving fluid, facing each other, characterized in that the angle (fGes) between the ridge ( 14) defining (finishing) the oblong discharge orifice (11) of the distributor (7), at its pitch circle (15), and the edge (16) delimiting (starting) the oblong suction orifice (10) at its pitch circle (15), when viewed in the direction of rotation of the cylindrical body (1) is formed from a bean angle (<B) and an expansion angle (YEX ) which is obtained according to the formula cos fEx 1 - b max T. * r. FK * tg 9 <depending on: - Maximum operating pressure (Pb max Max - Dead space (VT) - Inclination angle (t2 of the motion transmitter (for variable displacement units < ..max) -The compressibility index) of the driving fluid - Of the pitch circle radius of the piston (re) - Of the piston surface (FK)) A distributor according to Claim 1,   characterized in that the dead space (VT) is determined in accordance with   staggering the turning angle and taken for: - (VTC) = minimum dead space at the inland dead center, in the case of fixed displacement units   (VTV) = VTC at (VTC + 0.5, FK, ro, tg "ax) for valves with variable displacement.