FR2838789A1 - ALTERNATE PISTON MACHINE - Google Patents

Abstract

Machine with alternating piston, in particular air conditioning compressor for motor vehicles, comprising a cylinder block with pistons movable inside the cylinder block, and comprising piston shoes, which with a surface in the form of a spherical segment are guided in a piston clamping and which slide with a flat surface on a disc or a ring more or less inclined, the disc or the ring being driven in rotation using a shaft to thus transform the rotational movement of the shaft in a lifting movement of the pistons.

Description

* * * The invention relates to an alternating piston machine, in particular

  air conditioning compressor for motor vehicles, comprising a cylinder block with movable pistons inside the cylinder block, and comprising piston shoes, which with a spherical segment-shaped surface is guided in a piston clamping and which slide with a flat surface on a more or less inclined disc or ring, the disc or ring being rotated by means of a shaft, thus transforming the rotational movement of the shaft into a movement of

lifting the pistons.

  Such piston alternating machines are known.

  In these alternating piston machines, the use of piston shoes of the same type has been observed so far, both on the pulley and on the block side.

  nutation disc or swivel ring cylinders.

  It is also known that these piston shoes are coated both on the spherical segment side and on the flat surface and that they roll on pivoting discs or pivoting steel rings. There are also known stamped steel pads which roll on brass swivel discs or swivel discs coated with bronze. The raw material of a brass swivel disc weighing approximately 700 g where the manufacture of a swivel disc coated with bronze is

relatively expensive.

  The object of the invention is to provide an alternating piston machine which does not

not have these drawbacks.

  The object is achieved by an alternating piston machine, in particular an air conditioning compressor for motor vehicles, comprising a cylinder block with movable pistons inside the cylinder block, and comprising piston shoes, which with a surface in the form of spherical segment wind guides in a piston clamping and which slide with a flat surface on a disc or a ring more or less inclined, the disc or the ring being entralAne in rotation using a tree to transform the movement of rotation of the shaft in a lifting movement of the pistons, the piston shoes and / or the two rolling surfaces of the disc / of the ring being configured, according to the invention, so, one differs according to their stress, the piston shoes or the rolling surface of the disc / ring less stressed presenting on the less stressed surface, dimension

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  traction force or suction force side, exceptional operating properties weaker than cylinder block side (pressure force side). The piston shoes according to the invention and / or the rolling surfaces of the disc I of the ring thus leads to reduced manufacturing costs, the pedestal shoes and / or the rolling surfaces without functional properties that can be manufactured in a more economical way. Since the piston shoes which are less stressed are also not coated, they are easily recognizable during assembly and do not

  not lead to confusion or improper assembly.

  In addition, an alternating piston machine is preferred in which the piston pads have a unilateral anti-wear coating, namely only on the

  flat surface, or in which the disc / ring does not have an anti-

  wear only on the cylinder block side (pressure force side). The spherical surface does not undergo significant stresses and therefore does not require coating, which further reduces manufacturing costs. A bilateral coating of the piston shoes is only expensive for coatings with cured substances. Anodized aluminum piston pads are also preferred. This has the advantage that on a starting material a ceramic layer is applied, which reduces friction and the tendency to seize. Another alternating piston machine according to the invention is characterized in that the wind piston pads made of sintered bronze, bronze, brass or aluminum and have, outside the spherical segment touching the piston, a bearing of a radius spherical RK before the spherical segment with the lateral surfaces of the

  radius RN does not continue until it reaches the flat surface.

  We also prefer an alternating piston machine where the anti-wear coating is a layer of a cured substance which is applied to the piston pads

  after rectification and / or running-in and trovalisation.

  An alternating piston machine according to the invention is characterized in that the bearing serves as an exhaust surface during the deformation or the recompression or the calibration of the sintered piston pads. In addition, an alternating piston machine is preferred, where the bronze, brass or aluminum cast skids to obtain their approximate shape, the dimensional precision of the spherical segment then being obtained by stamping. We also prefer an alternating piston machine where the

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  flat surface of the piston shoes is machined by grinding and / or lapping, the shoes

  then being trovalises to avoid asperites.

  Another alternating pedestal machine is characterized in that the less stressed piston pads or the side of the disc / ring less stressed do not have an anti-wear coating. We also prefer an alternating piston machine where the more stressed piston pads have an anti-wear coating only on the flat surface, or only the more stressed disc / ring rolling surface has an anti-wear coating, the anti-wear coating which can be a layer of cured substance which is applied to the piston pads

  after rectification and / or running-in and trovalisation.

  An alternating piston machine is also preferred where the piston shoes which are less stressed are made of plastic. We also prefer an alternating piston machine where the piston shoes which are more stressed are made with

  manufacturing processes, materials and coatings which have just been described.

  The invention will now be described using the figures.

  FIG. 1 represents a cross section of an alternating piston machine, FIG. 2 represents a piston shoe,

  Figure 3 shows a piston pad with bearing.

  In Figure 1 an alternate piston machine is shown in section. In this alternating piston machine, the rotation of a drive shaft 1 must be transformed into a lifting movement of the pistons 2. For this purpose, a more or less inclined disc or ring 3 rotates together with the shaft 1 The force transmission of the disc or ring 3 on the pistons is ensured by pads 4 which with their flat surface 5 follow the inclination of the disc or ring 3 and slide on the disc and or the ring. 3 in rotation, and which transmit the force on the pistons 2

  through their spherical surface 6. The pistons 2 slide in a block

  cylinders 9, into which a refrigerant is sucked and compressed.

  During the compression stroke, the refrigerant is compressed at a high pressure, which consequently generates a reaction force on the surface of the piston 2. This reaction force is then transmitted to the pivoting ring 3 (puts

  then on the shaft 1) by the piston shoe 4.1 points towards the cylinder block side.

  During the suction stroke, the piston 2 is partially withdrawn from the cylinder block a

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  ['using the swivel disc or the swivel ring 3 by means of the piston shoe 4.2, the resulting forces acting on the piston 2 by the suction pressure and the discharge pressure being then considerably reduced than during of the compression stroke. As a result, the force and friction system undergoes piston pads 4.2 significantly less stresses than the force and friction system of piston shoes 4.1 and their rolling surfaces on the pivoting disc or the pivoting ring 3 sides cylinder block. Anti-wear measures, which must be taken on the more stressed surface, are therefore not necessary according to the invention on the less stressed surface. As anti-wear measures, you can choose the

  coatings and / or materials which will be described later.

  The cylinder block 9 is arranged in the casing 11 of the alternating piston machine, which is closed by a cylinder head 13 configured as a cover. In the cylinder head 13 are suction zones 15 and discharge zones 17 from which the refrigerant is sucked from the outside into the machine or discharged to the outside. A valve plate 19 with intake valves for the suction side and evacuation valves for the discharge side is arranged between the cylinder blocks g and the cylinder head 13. The shaft 1 is housed in the casing 11 by l '' through a front radial bearing 21, and in the cylinders

  (a) by means of a rear radial bearing 23 and an axial bearing 25.

  The pivoting ring 3 is arranged on the shaft 1 using a drive rod not shown and a sliding bush 27 and can take different adjustment angles using an adjustment device. appropriate. When the machine is stopped, a spring 29 can adjust the sliding bush 27 and thus the angle of the pivoting ring 3 over a minimum starting stroke. Towards the outside, the shaft 1 in the housing 11

  is sealed with a slip ring seal.

  Figure 2 shows the side view of a piston shoe 4 according to the invention. The piston pad 4 has, as already described for FIG. 1, a surface 6 in the form of a spherical segment housed in the tightening of the piston 2, and a surface

  plane 5 sliding on the pivoting disc 3 in rotation.

  The surface 6 in the form of a spherical segment comprises an arc-shaped part of a spherical radius RK which represents the point of accommodation inside the tightening of the piston, and a lateral surface 8 in the form of an arc having a radius narrower,

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  the radius RN of the neighboring surface. In FIG. 2, the shoe 4 is provided, for example on its flat surface 5, with a coating of a curing substance 100, in the case of aluminum for example with an anodized layer. Due to the tribological situation, it is necessary that in particular on the more stressed surface of the pivoting disc or of the pivoting ring 3, exceptional operating properties are present between the piston 2 and the piston pad 4 as well as between the disc. swivel or the swivel ring 3 and the piston shoe. This can be achieved with layers of curing substance. For this purpose, it suffices to coat the flat surface 5 of the spherical segment 4. The layer of cured substance 100 is applied after rectification and / or running-in and trovalisation of the piston shoes 4. Good properties of exceptional operation can also be obtained by piston shoes in sintered bronze, bronze, brass or aluminum alloys. Another configuration of a piston pad for these materials is illustrated in FIG. 3. In the case of sintered piston pads, one can provide, outside the spherical segment 6 of the spherical radius RK touching the 1S piston, a bearing 7 for be able to more precisely reach the spherical form by recompression or calibration. The lateral surfaces 8 of the piston pad 4 serving

  then, like the bearing 7, of the exhaust surface during deformation.

  The bronze, brass or aluminum piston shoes can also be cast to obtain their approximate shape. Dimensional precision is then obtained by stamping. In the case of sintered bronze, bronze, brass and aluminum materials, the flat surface S is produced by grinding and / or running-in, and the pads

  of piston wind trovalises to avoid asperites.

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Claims (12)

  1. Alternating piston machine, in particular air conditioning compressor for motor vehicles, comprising a cylinder block (9) with pistons (2) movable inside the cylinder block (9), and comprising piston shoes, which with a surface in the form of a spherical segment wind guides in a piston clamping and which slide with a flat surface on a disc or a ring more or less inclined, the disc or the ring being driven in rotation using a shaft to thus transform the rotational movement of the shaft into a lifting movement of the pistons (2), o characterized in that the piston shoes and / or the two rolling surfaces of the disc / ring wind configured differently depending on their stress, the piston shoes or the rolling surface of the disc / ring less stressed presenting on the less stressed surface (traction force, suction force) properties of exceptional functioning more low that side bloccylindres (cate pressure force).   2. Alternating piston machine, in particular air conditioning compressor for motor vehicles, comprising a cylinder block with movable pistons inside the cylinder block, and comprising piston shoes, which with a surface in the form of a spherical segment ( 6) wind guides in a piston clamping and which slide with a flat surface on a disc or a ring (3) more or less inclined, the disc or the ring (3) being driven in rotation using a shaft to thus transform the rotational movement of the shaft into a lifting movement of the pistons, characterized in that the piston pads have a unilateral anti-wear coating, namely only on the flat surface or that the disc / ring (3) does not have a   anti-wear coating as cylinder block pad (pressure force side).   3. alternating piston machine according to claim 1 or 2, characterized in that   that the piston shoes (4) are made of anodized aluminum.   4. Alternating piston machine, in particular air conditioning compressor for motor vehicles, comprising a cylinder block with movable pistons 7 2838789   the interior of the cylinder block, and comprising piston shoes, which with a spherical segment-shaped surface wind guides in a piston clamping and which slide with a flat surface (5) on a disc or a ring more or less inclined, the disc or the ring being rotated by means of a shaft (1) thereby transforming the rotational movement of the shaft (1) into a lifting movement of the pistons, characterized in that the s piston pads wind in sintered bronze, bronze or aluminum, brass and have, outside the spherical segment touching the pistons, a bearing with a spherical radius RK before the spherical segment with lateral surfaces 8   of the radius RN continues its course until it reaches the flat surface (5).   o 5. alternating piston machine, in particular according to claim 2 or claim 3, characterized in that the anti-wear coating is a layer of a cured substance which is applied to the piston pads (4) after rectification and / or rod age and trov alization.   6. Alternating piston machine, in particular according to claim 4, characterized in that the bearing (7) and the lateral surfaces serve as exhaust surfaces during deformation or recompression or calibration of the pads   piston (4) if necessary frits.   7. Alternating piston machine, in particular according to claim 4, characterized in that the pads (4) in bronze, the aion or aluminum are cast to obtain their approximate shape, the dimensional precision of the spherical segment.   then being obtained by stamping.   8. alternating piston machine, in particular according to claim 2, claim 6 or claim 7, characterized in that the flat surface of the piston shoes (4) is produced by grinding and / or running in, the shoes (4) being then trovalises. 9. alternating piston machine, in particular according to claim 1 to claim 3, characterized in that the piston shoes (4) less stressed or the surface of the disc / ring (3) less stressed do not have coating anti wear. 8 2838789   10. Alternating piston machine, in particular according to claim 1 to claim 5, characterized in that the piston shoes (4.1) which are more stressed or the rolling surface of the disc / ring (3) which is more stressed have a coating. antiwear. 11. Alternating piston machine, in particular according to claim 1, characterized in that the pedestal pads (4. 2) are not stressed when made of plastic. 12. Alternating piston machine, in particular according to claim 1, characterized in that the piston shoes (4.1) which are more stressed are produced according to the