EP1464836A2 - Axial piston compressor in particular CO2-compressor for a car air-conditioning apparatus - Google Patents

Abstract

The device (10) has a swivel plate (107) pivotable relative to and driven by a drive shaft (104) and joined to a sliding sleeve (108) and a supporting element (109), whereby the pistons have linkage arrangements with which the swivel plate is in sliding engagement. The linkage connection (116) between the drive shaft and swivel plate is essentially only for torque transfer and the supporting element is essentially only for axial support of the piston and/or gas pressure.

Description

The invention relates to an axial piston compressor, in particular a CO ₂ compressor for motor vehicle air conditioning systems, according to the preamble of claim 1.

Such an axial piston compressor is for example from DE 197 49 727 A1 known. This comprises a housing in which in a circular arrangement several axial pistons are arranged around a rotating drive shaft. The Driving force is from the drive shaft via a driver to an annular Swivel disc and from this in turn to the parallel to the drive shaft Piston translationally displaceable. The ring-shaped swivel disc is pivotable on an axially displaceably mounted sleeve on the drive shaft stored. An elongated hole is provided in the sleeve through which the driver mentioned round picks. Thus, the axial mobility of the sleeve on the drive shaft limited by the dimensions of the elongated hole. An assembly is done by a Push the driver through the slot. Drive shaft, driver, Sliding sleeve and swivel plate are arranged in a so-called engine room, in the gaseous working medium of the compressor is present at an equipped pressure. The delivery volume and thus the delivery rate of the compressor depend on Pressure ratio between the suction side and pressure side of the pistons or accordingly depending on the pressures in the cylinders on the one hand and in the engine room on the other hand.

The driver mentioned serves both for torque transmission between Drive shaft and swivel plate as well as for axial support of the pistons, i.e. for gas power support. The construction according to DE 197 49 727 A1 is based on an older construction, for example according to DE 44 11 926 A1, in which the Driver is formed in two parts, with a first attached to the drive shaft Driver part is arranged at a considerable distance next to the swivel plate and a second driver part engaging in the first in an articulated manner has a lateral part Extension of the swivel plate forms. The disadvantage of this design is that it has axial minimum length of the compressor is significantly determined. In addition, one has swivel disk having a thickened hub part through its lateral extension comparatively large moment of inertia with a considerably from the drive axis distant center of gravity, causing a sudden change in rotational speed with appropriate inertia leads to an inclination adjustment of the swivel plate. Furthermore, the center of gravity away from the tilt axis causes an unbalance, because the engine only for a (preferably) medium swivel plate tilt angle can be balanced. The situation is similar with the construction according to the EP 1 172 557 A2.

Compared to these known constructions, the proposal stands out according to the DE 197 49 727 A1 is characterized by a much more compact design. inertial forces are reduced to a minimum. Furthermore, exact compliance with the internal dead center position of the pistons guaranteed. So-called open spaces are prevented. A preferred embodiment according to DE 197 49 727 A1 will now be described in more detail with reference to FIGS. 10 and 11. An axial piston compressor 1 has, for example, seven pistons 2, which in Arranged circumferentially at the same angular distance from each other and in Cylinder bores 3 of a cylinder block 4 are axially movable back and forth. The stroke movement of the pistons 2 takes place through the engagement of a drive shaft 5 oblique annular swivel plate 6 in engagement chambers 7, the each adjoin closed cavities 8 of the pistons 2. For that essentially play-free sliding engagement in any inclined position of the swivel plate 6 are between this and a spherically curved inner wall 10 of the engagement chamber 7 on both sides Ball segments or ball segment-like sliding blocks 11 and 12 are provided, so that the swivel plate 6 slides between them as it rotates. The drive transmission from the drive shaft 5 to the annular swivel plate 6 takes place through a driver bolt 13 fastened in the drive shaft 5, the latter, for example spherical head in a radial bore 16 of the annular swivel disk 6 intervenes. The position of the driver head 15 is curled so that its Center point 17 with that of the spherical shape of the spherical segments 11, 12 matches. In addition, this center lies on a circular line, the geometric axes of the seven pistons. In this way the dead center position of the pistons 2 is precisely determined and a minimal harmful one Space guaranteed.

The head shape of the free driver end enables the inclination of the to be changed annular swivel plate 6 by the driving head 15 a bearing body for the swiveling movement of the swash plate 6 changing the stroke width of the pistons 2 forms. Another prerequisite for pivoting the disc 6 is Slidability of its bearing axis 20 in the direction of the drive shaft 5. This is 11, the bearing axis 20 by two coaxially on both sides one Sliding sleeve 21 bearing bolts 22, 23 formed, which also in radial Bores 24, 25 of the annular swivel plate 6 are mounted. The sliding sleeve 21 preferably has bearing sleeves 26, 27 on both sides which define the annular space 28 bridge between the sliding sleeve 21 and the annular swivel disk 6. The limitation of the displaceability of the bearing axis 20 and the maximum Inclination of the swivel plate 6 results from the driving pin 13, by penetrating an elongated hole 30 provided in the sliding sleeve 21, so that the sliding sleeve 21 finds 30 stops at the ends of the elongated hole. The power for the angular adjustment of the swivel plate 6 and thus for a regulation of the Compressor results from the sum of the pistons 2 on both sides opposing pressures so that this force from the pressure in the engine room 33 is dependent. A flow connection can be used to regulate this pressure be provided with an external source of pressurized gas. The higher the pressure on the Engine room side of the piston 2 or in the engine room 33 relative to the pressure the opposite side of the piston 2, the smaller the stroke of the piston 2 and thus the delivery capacity of the compressor. The setting of the position of the Sliding sleeve 21 and thus the stroke of the piston 2 or the delivery rate of the Compressor is carried out by at least one interacting with the sliding sleeve 21 Spring 34, 35. Preferably, the sliding sleeve 21 is between two Helical compression springs 34, 35 included, which are arranged on the drive sleeve 5 are.

A disadvantage of the known construction is that the contact principle described non-uniform deformation behavior between the driver and the swashplate of the swashplate running sides, which subsequently results in one leads to unfavorable running behavior of the sliding blocks on the swivel plate. In the area the cylindrical bore of the swash plate, in which the spherical end of the Carrier supports, it comes due to the very small residual wall thickness to a strong deformation in this area. This will change the running properties the sliding blocks on the swivel plate are impaired accordingly. This problem has already been recognized. To avoid this, for example, in the WO 02/38959 A1 different geometrical shapes between drivers and associated mounting hole have been proposed.

Another swash plate engine is known from FR 2 782 126 A1 which a driver protrudes into a swivel plate. Compared to the state of the Technology according to DE 197 49 727 A1, however, the swivel plate is also radial Articulated direction and therefore has no displacement in the radial direction. The advantage of this design is that the associated joint has the forces can be transferred across the surface, with the result that a relatively small construction is possible.

• Übertragung des Antriebsmoments (durch Mitnehmer/Drehmomentstütze), sowie
• Abstützung der Schwenkscheibe so, dass der obere Totpunkt der Kolben unverändert bleibt.

In summary, however, it can be stated that all known constructions have the following disadvantages, due to the overlapping of several functions:

• Transmission of the drive torque (by driver / torque arm), as well
• Support the swivel plate so that the top dead center of the pistons remains unchanged.

• Durch beide Einflüsse wird der in der Regel kugelförmige Kopf des Mitnehmers an zwei Bereichen erheblicher Flächenpressung unterworfen;
• Diese Flächenpressung tritt auch an den entsprechenden Stellen der Schwenkscheibe auf;
• Durch die erwähnten Flächenpressungen kommt es leicht zu Verformungen, die sich aufgrund der Gegebenheiten unkontrolliert gegenseitig beeinflussen können.

This leads to the following behavior:

• As a result of both influences, the generally spherical head of the driver is subjected to considerable surface pressure in two areas;
• This surface pressure also occurs at the corresponding points on the swivel plate;
• The surface pressures mentioned easily lead to deformations which, due to the circumstances, can influence one another in an uncontrolled manner.

The well-known driver / torque arm is both by the torque acted upon as well as by the support force of the swash plate in response to resulting gas forces. Both force and bending moment curves show their maximum in the area of the mount on the drive shaft. Accordingly, the Drive shaft must be dimensioned. The same naturally also applies to the dimensioning both the driver and the swivel plate, especially in the area of Location hole for the driver. The stronger dimensioning naturally leads inevitably to correspondingly higher masses and thus moments of inertia. This can adversely affect the control behavior and must be compensated. The stronger dimensioning also means that the pistons are assigned Joint arrangements are dimensioned larger or are dimensioned larger have to. This applies to both the sliding blocks and the pistons themselves.

To remedy this, measures must be taken to reduce the impact Forces are hit.

Accordingly, the present invention is based on the object To create compressors of the type mentioned, which without restriction Functional reliability can be built more easily.

• Gaskraftabstützung und
• Drehmomentübertragung

im Bereich zwischen Schwenkscheibe und Antriebswelle vermieden bzw. entkoppelt wird. Durch diese Entkoppelung werden die einzelnen Bauteile zur Übertragung der vorgenannten Kräfte und Momente entlastet und können entsprechend kleiner dimensioniert werden. Insbesondere können auch Toleranzspiele zwischen den einzelnen Bauteilen exakter eingestellt und überhöhte Flächenpressungen vermieden werden. Die axiale Abstützung der Kolben einerseits und die Übertragung von Drehmomenten von der Antriebswelle auf die Schwenkscheibe andererseits wird also erfindungsgemäß unterschiedlichen Bauteilen zugeordnet.This object is achieved by the characterizing features of claim 1. The essence of the present invention therefore lies in the fact that the functional overlay present in the prior art, namely

• Gas power support and
• torque transmission

is avoided or decoupled in the area between the swivel plate and the drive shaft. As a result of this decoupling, the individual components for transmitting the aforementioned forces and moments are relieved and can be dimensioned correspondingly smaller. In particular, tolerance games between the individual components can be set more precisely and excessive surface pressures can be avoided. The axial support of the pistons on the one hand and the transmission of torques from the drive shaft to the swivel plate on the other hand are thus assigned different components according to the invention.

It has proven to be useful to use the torque between the tilt joint Transfer swashplate and drive shaft, especially since usually two Bolt joints are available for this. The play of this pin bearing is exact adjustable. Pressure points can be avoided. Overlay of circumferential and Axial forces in the area between the support element and swivel plate avoided according to the invention.

Preferred embodiments and construction details of the invention Solution are described in the subclaims.

Fig. 1

eine erste Ausführungsform eines erfindungsgemäßen Verdichters im schematischen Längsschnitt;

Fig. 2 bis 5

verschiedene Ausführungsformen der gelenkigen Verbindung zwischen Antriebswelle und Schwenkscheibe unter gleichzeitiger Darstellung der axialen Abstützung der Schwenkscheibe gegenüber der Antriebswelle, jeweils im schematischen Querschnitt;

Fig. 6 und 7

zwei unterschiedliche Ausführungsformen eines Axialkraft-Übertragungselements zwischen Schwenkscheibe und Antriebswelle im Längsschnitt bzw. in Seitenansicht;

Fig. 8

zweites Ausführungsbeispiel eines erfindungsgemäß ausgebildeten Verdichters im schematischen Längsschnitt; und

Fig. 9

ein weiteres Ausführungsbeispiels eines erfindungsgemäß ausgebildeten Verdichters im schematischen Längsschnitt.

Concrete embodiments of the construction according to the invention are explained in more detail below with reference to the attached drawing. This shows in:

Fig. 1

a first embodiment of a compressor according to the invention in schematic longitudinal section;

2 to 5

different embodiments of the articulated connection between the drive shaft and the swivel plate, with simultaneous representation of the axial support of the swivel plate relative to the drive shaft, each in a schematic cross section;

6 and 7

two different embodiments of an axial force transmission element between swivel plate and drive shaft in longitudinal section or in side view;

Fig. 8

second embodiment of a compressor designed according to the invention in a schematic longitudinal section; and

Fig. 9

a further embodiment of a compressor designed according to the invention in a schematic longitudinal section.

The compressor 100 shown in FIG. 1 in a schematic longitudinal section comprises one Cylinder block 101, a housing 102 delimiting an engine room 103 and a drive shaft 104, which via a swivel plate mechanism 105 inside of the engine room 103 several, in particular seven evenly over the circumference drives axial pistons 106 arranged around the drive shaft 104, which inside of the cylinder block 101 are axially displaceably mounted.

The swivel plate mechanism 105 comprises an annular swivel plate 107, both with an axially displaceably mounted on the drive shaft 104 Sliding sleeve 108 and with a distance from the drive shaft 104 with this pivoting support element 109 is pivotally connected, the piston 106 each have a joint arrangement 110 on which the annular swivel disk 107 is in sliding engagement. The hinge arrangement 110 is corresponding to FIG trained according to the prior art and also comprises two semi-spherical Sliding blocks 111, 112.

The sliding sleeve 108 is also formed as in the prior art and through Helical compression springs 113 axially preloaded.

The support element 109 is in the embodiment shown as a spherical head educated. This is located at the free end of a pin-like power transmission element 114. The support member 109 engages in an annular swivel plate 107, namely an elongated hole 115 formed on the ring element thereof a whose bore axis is radial and whose longer cross-sectional axis is in Extends circumferential direction. This ensures that the support element 109 in the essential only for the axial support of the pistons 106 or for gas force support serves. The corresponding forces are assigned via the support element and the Transfer power transmission pin 114 to the drive shaft 104. The Torque transmission between drive shaft 104 and swash plate 107 takes place exclusively via an articulated connection 116 arranged between them (see figures 2 to 5). The support element 109 can also be cylindrical or barrel-shaped instead of spherical be trained. In the latter two cases, the longitudinal axis extends of the support element perpendicular to the pin-like force transmission element 114. This Embodiment has the advantage that the axial support via a line contact between the support element and the corresponding radial bore in the swivel plate 107 takes place.

Due to the decoupling of torque transmission and gas force support it is possible to dimension the swivel plate relatively small and accordingly easy to build without deformation. It is also easier that To design power transmission mechanism free of play with the consequence that the Compressor works with less noise.

The swivel joint 116 between the drive shaft 104 and swivel plate 107 can have different designs, as can be seen in FIGS. 2 to 5. These figures also show that the support element 109 is inside the elongated hole 115 has sufficient play in the circumferential or rotational direction, so that forces due to the drive torque are never effective. By the support element is only absorbed and transmitted axial gas forces.

In the embodiment according to FIG. 2, the torque transmission takes place between Drive shaft 104 and annular swivel plate 107 over two relative to Drive shaft 104 diametrically extending bolts between sliding sleeve 108th and swivel plate 107 are effective. The sliding sleeve itself is over one Key arrangement 117 is connected in a rotationally fixed manner to the drive shaft 104. The annular swivel plate 107 is around by the bearing bolts 118th defined axis pivotable. The pin-like power transmission element 114 extends through the sliding sleeve 108 with play.

In the embodiment according to FIG. 3, the anti-rotation lock takes place between Sliding sleeve 108 and drive shaft 104 through the pin-like power transmission element 114. Otherwise, the construction according to FIG. 3 coincides with that 2.

The embodiment according to FIG. 4 essentially corresponds to that according to FIG. 3; because also in the embodiment according to FIG. 4, the anti-rotation lock takes place between Drive shaft 104 and sliding sleeve 108 through the power transmission pin 114. Die Coupling takes place in the embodiment of FIG. 4 only on the spherical support member 109 opposite end of the power transmission pin 114th

5 shows a further solution for the connection between drive shaft 104 and annular swivel plate 107, without the interposition of hinge pins 118. These are in the embodiment according to FIG. 5 by corresponding Radial journal 119 of the sliding sleeve 108 replaced. These radial pins 119 define one Swivel bearing for the annular swivel plate 107 around by the radial pin 119 defined transverse axis 120. Otherwise, the construction according to FIG. 5 corresponds that of FIG. 2.

Figures 6 and 7 show two different embodiments for the Connection between a spherical support element 109 and a pin-like Power transmission element 114. In the embodiment according to FIG. 6, this is spherical Support member 109 at one end of a sleeve-like power transmission element 114 arranged, in particular welded (preferably friction welding connection).

7, the pin-like force transmission element 114 still a ring heel 121, which acts as a stop for the introduction in a receiving bore formed in the drive shaft 104 is used. The pen-like Power transmission element 114 is arranged in the embodiment according to FIG. 1, that it protrudes obliquely from the drive shaft 104, in such a way that at a middle inclination position of the annular swivel plate 107 the longitudinal axis of the pin-like power transmission element 114 radially to the annular swivel plate 107 is directed.

The abovementioned stop 121 also ensures, moreover, that the center 122 of the spherical support element 109 coincides with the center of the joint arrangement 110 assigned to each piston without additional adjustment measures during the assembly of the compressor. This installation position is preferred; however, it can also be advantageous to provide a slight _“ offset” of up to approximately 1/10 mm between the circular line on which the center point of the support element 109 on the one hand and the circular line on which the center points of the piston joint arrangements 110 lie on the other hand to vary the clearance slightly depending on the swivel angle. The center point 122 of the support element 109 preferably lies on a circular line that extends radially slightly outside the circular line on which the center points of the piston-joint arrangement 110 lie. This embodiment has the advantage that at no time do tilt moments act on the swivel plate, which tilt the swivel plate in a different, unintended direction.

At this point it should also be mentioned again that it is conceivable to have two so-called Provide gas force supports or support elements 109, each for support in serve axially opposite direction. This allows a so-called double fit with the problem of over-determination can be avoided. The two support elements can also be arranged asymmetrically.

In the case of a single gas power support, this could be the swivel plate just before support the top dead center position, since the maximum force is due to this position There is a valve opening. With such a variant, however, it must be noted that that the support joint continues to project with its center point with the center point the piston joint assembly 110 coincides. It should also be noted that at Arrangement of the joint before the dead center position the swivel plate on its main load side (Pressure) is a little thinner than on the opposite side of the load (train).

8 shows a further exemplary embodiment of a compressor according to the invention, at the parts that have already been described with reference to FIG. 1 with the same reference numbers as marked in Fig. 1.

The swivel plate mechanism 105 is in the exemplary embodiment according to FIG. 8 identical. 8 differs from that 1 essentially only in that the cylinder block 101 is in the Engine room 103 extends conically into it, thereby extending the guidance of the Piston 106 is reached. The cone 123 is designed so that it fits into the Annulus 124 between sliding sleeve 108 and annular swivel disk 107 hineinerstreckt. This allows the compressor to be built with regard to its overall length reduce additionally.

In the embodiment according to FIG. 9, the support element 109 is a at the free end L-shaped power transmission element 114 arranged at the free end of the shorter leg 125, which extends obliquely radially outwards. The longer one Leg 126 extends approximately parallel to the drive shaft 104 and is axially on one supported with the drive shaft 104 rotatably connected support plate 127. The Support disk 127 is in turn around the drive shaft 104 extending needle bearing 128 supported on the housing 102.

This construction has the advantage that there is a reveal in the drive shaft 104 can be avoided for the pin-like power transmission element 114. Accordingly, the diameter of the drive shaft 104 can be greatly reduced become.

Fig. 9 also makes it clear that the so-called gas force support can alternatively also from the outside instead of engaging inside the swashplate, in which case the Piston rotation lock not on the inside of the engine housing 102, but instead would be shifted inwards to the drive shaft.

All features disclosed in the registration documents are considered as claimed according to the invention insofar as they are used individually or in combination the state of the art are new.

reference numeral

100

compressor

101

cylinder block

102

casing

103

Machine Room

104

drive shaft

105

Swivel-disk mechanism, our

106

piston

107

Swivel disc (ring-shaped)

108

sliding sleeve

109

support element

110

joint arrangement

111

slide

112

slide

113

Helical compression spring

114

Power transmission element (pin-like)

115

Long hole

116

articulation

117

key arrangement

118

bearing bolt

119

radial pin

120

transverse axis

121

Ring heel or stop

122

Center of the support element

123

cone

124

annulus

125

leg

126

leg

127

support disc

128

needle roller bearings

Claims (7)

Axial piston compressors (100), in particular CO ₂ compressors for motor vehicle air conditioning systems, with an inclination to a drive shaft (104) that can be rotated by the drive shaft (104), in particular an annular swivel disk (107), this being both with a on the Drive shaft (104) is axially displaceably mounted as a sliding sleeve (108) and at least one at a distance from the drive shaft (104) rotatably arranged with this support element (109), the pistons (106) each having a joint arrangement (110), on which the swivel disk (107) is in sliding engagement,
characterized in that
the articulated connection (116) between the drive shaft (104) and the swivel plate (107) serves essentially only for torque transmission and the support element (109) serves essentially only as an axial support for the pistons (106) or gas force support. Compressor according to claim 1,
characterized in that
the support element (109) is spherical, cylindrical or barrel-shaped and is connected to the drive shaft (104) via a force-transmitting element (114) in particular. Compressor according to claim 1 or 2,
characterized in that
in the case of an annular swivel disk (107), the force transmission element (114) is a bolt which projects obliquely from the drive shaft (104), so that
at an average inclination position of the swivel plate (107) the pin axis is directed radially to the swivel plate (107). Compressor according to claim 1 or 2,
characterized in that
the support element (109) is arranged at the free end of an L-shaped force transmission element (114), one leg (126) of which extends approximately parallel to the drive shaft (104) and axially on a support disc (127) connected to the drive shaft (104) in a rotationally fixed manner or the like. Radial projection is supported. Compressor according to one of claims 1 to 4,
characterized in that
the swivel disk (107) has an elongated hole (115) defining an engagement space for the support element (109), the longitudinal axis of the bore extending radially and the longer cross-sectional axis extending in the circumferential direction. Compressor according to one of claims 1 to 5,
characterized in that
the center point (122) of the support element (109) lies on a circular line which either covers the circular line on which the centers of the piston-joint arrangements (110) lie or extends radially slightly outside of the latter circular line. Compressor according to one of claims 1 to 6,
characterized in that
two support elements (109) are provided, and these each serve for support in the axially opposite direction.

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