WO2004111451A1

WO2004111451A1 - Axial piston compressor, particularly a compressor for the air-conditioning system of a motor vehicle

Info

Publication number: WO2004111451A1
Application number: PCT/EP2004/005106
Authority: WO
Inventors: Otfried Schwarzkopf; Ullrich Hesse; Michael Arnemann
Original assignee: Zexel Valeo Compressor Europe Gmbh
Priority date: 2003-06-17
Filing date: 2004-05-12
Publication date: 2004-12-23
Also published as: US20070137474A1; JP4640656B2; JP2006527805A; EP1636492B1; EP1636492A1

Abstract

The invention relates to an axial piston compressor, particularly a compressor for the air-conditioning system of a motor vehicle, comprising a housing and a compressor unit, which is placed inside said housing, is driven by a drive shaft (104) and which serves to draw and compress a refrigerant. The compressor unit comprises, in a cylinder block, axially reciprocating pistons and a swash plate (107), which drives the pistons and which rotates with the drive shaft. With a predetermined rotationally moved mass of the swash plate (107) on the one hand and/or with a specified translationally moved mass on the other, the average radius, which is stipulated by the geometry and/or by the density distribution, and/or the average height of the swash plate (107) or of the pivotal portion of the swash plate is/are selected in such a manner that centrifugal forces occurring as the swash plate rotates are sufficient for counteracting the pivotal motion of the swash plate (107) in a deliberately controlling manner whereby influencing the piston stroke and thus the delivery capacity, in particular, reducing or limiting it.

Description

Axial piston compressor, in particular compressor for the air conditioning system of a motor vehicle

Description

The invention relates to an axial piston compressor, in particular a compressor for the air conditioning system of a motor vehicle, with a housing and a compressor unit arranged in the housing and driven via a drive shaft for the suction and compression of a refrigerant, the compressor unit and a piston running axially back and forth in a cylinder block the piston driving, rotating with the drive shaft swivel plate.

Such an axial piston compressor is known for example from DE 197 49 727 AI. This comprises a housing in which a plurality of axial pistons are arranged in a circular arrangement around a rotating drive shaft. The drive force is transmitted from the drive shaft via a driver to an annular swivel disk and from this in turn to the pistons which are translationally displaceable parallel to the drive shaft. The annular swivel disk is pivotally mounted on an axially displaceably mounted sleeve on the drive shaft. An elongated hole is provided in the sleeve, through which the driver mentioned extends. The axial mobility of the sleeve on the drive shaft is thus limited by the dimensions of the elongated hole. Installation takes place by pushing the driver through the slot. The drive shaft, driver, sliding sleeve and swivel plate are arranged in a so-called engine room, in which gaseous working medium of the compressor is present at a certain pressure. The delivery volume and thus the delivery capacity of the compressor are dependent on the pressure ratio between the suction side and the 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.

A somewhat different type of axial piston compressor is described, for example, in DE 198 39 914 AI. The swivel plate is designed as a swash plate, a non-rotatable receiving plate which is mounted opposite the swash plate being arranged between the swash plate and the pistons.

The following prior art is also pointed out:

DE 2,524,148 US 4,815,358 US 4,836,090 US 4,077,269 US 5,105,728

The compressors described in these publications include to take measures to avoid or reduce the imbalance of the engine during operation. For the rest, the known constructions have in common that the rotating components are relatively large compared to the translationally moving parts, namely pistons, piston rods, etc. and are accordingly heavy. Furthermore, the known constructions have in common that an additional disk acts on the actual swivel disk device by means of a suitable coupling mechanism. The plurality of rotating components are intended to cause the swivel disk device to set up a moment in the direction of the minimum stroke, as a result of which the control behavior is influenced.

The above-mentioned designs are all relatively complex, expensive, not very compact and are therefore unsuitable for the compressors for air conditioning systems that are now required by the automotive industry.

Even with series compressors, such as those used today in motor vehicles, one aims at a suitable dimensioning of the moving components or moving ones Masses to achieve a desired control behavior, namely that the centrifugal forces that occur when turning the swivel plate are sufficient to consciously counteract the swivel movement and thus influence, in particular reduce or limit, the piston stroke and thus the delivery rate. The series compressor 6SEU12C from DENSO has, for example, an engine with the following masses relevant for the control behavior:

Component Number Mass Component [g] Total mass [g]

Piston 6 41 246

Sliding block 12 5 60 translationally moved 306 g masses

Swashplate 1 391 391

Guide pins 2 20 40 rotating 431 g masses

The abovementioned numbers indicate that a considerable component mass is provided for parts which move in rotation. An attempt is therefore made to produce a sufficient counterforce or a sufficient counter torque with respect to the masses moved in translation. This basic idea is also based on DE 198 39 914 AI, where the rotating mass of the swivel plate or the swivelable portion of the swivel plate is dimensioned such that the centrifugal forces occurring when the drive plate is rotated are sufficient to consciously counteract the swivel movement of the swivel plate and thus to counteract it To influence the piston stroke and thus the delivery rate, namely to reduce or limit it or, in particular, to keep it constant.

The publication by Björn Fagerli, "A theoretical comparison of the mechanical control behavior of a R744 and a R134a automotive AC compressor", published as part of the Purdue Compressor Conference 2002, shows the influencing factors that act as moments around the tilting center of a swivel plate device These are the following moments, with the direction of the Moments are given and (-) regulating (in the direction of a minimum stroke) and (+) regulating (in the direction of the maximum stroke) mean:

- moment due to the gas forces in the cylinder rooms (+) - moment due to the gas forces from the engine room (-)

- moment due to a return spring (-)

- moment due to a spring (+)

- moment due to rotating masses (-); including moment due to center of gravity (e.g. swivel plate: tilt position ≠ center of mass): can be (+)

- moment due to translatory masses (+)

With regard to the mentioned 6SEU12C compressor from DENSO, which represents the typical design of a swash plate compressor, it should be noted that the mass of such a swash plate cannot be increased arbitrarily in order to change the control behavior. This is because, in the case of the compressors of the type described, the center of gravity of the swivel plate is generally at a clear distance from the swivel joint of the swivel plate. This construction is essentially due to the fact that the swivel plate must be coupled to the drive shaft or a component connected to the drive shaft in addition to a suitable guide on the drive shaft.

The mentioned distance from the center of gravity of the swivel plate and the tilt joint of the same leads to an imbalance of the engine, in particular as a function of the swivel plate tilt angle, and in the worst case leads to an regulating property (see above “position of the center of gravity”).

Thus, in the case of the compressors according to the prior art, both according to the printed and actually practiced prior art, a compromise must be made in that a predetermined mass of the swivel plate is provided in order to counteract the translatory masses manufacture. On the other hand, the mass of the swivel plate must not be too large, since the unbalance of the engine would then be excessive.

In order to address this problem, it has also been suggested that the pistons, i.e. the translational masses as low as possible, i.e. easy to build, for example from aluminum or other materials with lower specific density. In this regard, there is also a proposal to use hollow pistons.

However, even with these measures, constant regulation of the delivery rate at different speeds cannot be achieved. It should be noted that the term "constant control" is not to be understood as an exact statement. The delivery rate would only be constant if, for example, the tilting angle of the swivel plate device was halved when the speed was doubled. However, it should be borne in mind that other parameters affect the flow rate, such as the degree of delivery or oil spill or the like, if, for example, the tilt angle of the swivel plate changes.

The resetting torque of the swivel plate device is used for constant control of the delivery rate at changing speeds, since - as already explained - the swivel plate counteracts its inclined position due to the dynamic forces on the rotating part of the disk.

This behavior can be supported by spring forces or hydraulically, pneumatically or the like, so that as the speed increases, the delivery rate which is increased is at least partially compensated for by resetting the inclined position.

The case of a compensation of the up and down torque can also be very interesting. Changes in speed then do not intervene in the control. This means that a simpler control algorithm can be used.

As already explained above, such behavior can in principle be achieved by integrating an additional mass into the engine, for example Mass inertia, as described, affects the swivel plate device via a coupling mechanism.

However, it was also shown that the mass of the swivel plate cannot be increased arbitrarily without having to accept other disadvantages. This also applies in particular to the teaching according to DE 198 39 914 AI or EP 99 953 619 (application no.). The regulation proposed there with the mass of the rotating components can lead to a regulation behavior by means of which the delivery rate is largely independent of the speed. However, this is not inevitable. Overcompensation can also occur. The design criteria are not clear. The reason for this is that the mass of the rotating components only influences the set-up torque of the swivel plate proportionally.

The present invention is therefore based on the object of providing a compressor of the type mentioned at the outset, which optionally has a control behavior

Has compensation, overcompensation, constant control for the "delivery rate", with a minimum mass of the pivotable rotary components, so that a compact design of the compressor is possible.

According to the invention, this object is achieved by the characterizing features of claim 1, preferred structural details and further developments being described in the subclaims.

According to the invention, the desired control behavior of the compressor is therefore primarily not achieved with the component mass, but instead taking into account the moment of inertia of the swivel plate arrangement, which depends on its geometry.

A core idea of the invention is therefore to compensate for the moment due to translational masses directly, or also to overcompensate for the moment due to rotating masses. The set-up torque that is to be generated on a swivel plate device is a function of the speed or the angular velocity ω and the mass moment of inertia J of the swivel plate device:

M = f (ω ² ; J)

The moment of inertia itself is essentially a function of the component mass and the component geometry, for example in the case of a disk determined by the diameter “2r” and the disk thickness or height “h”:

j = f (m, r ² , h *)

Expressed even more precisely, the moment of inertia is essentially a function of the component density distribution and also the component geometry. The component density distribution takes into account, for example, swivel plates made of different materials, namely 2, 3 or more materials or a material with different density distribution (metal foam, heterogeneous material):

where S = density, r = swivel plate radius, and h = swivel plate height.

In addition, the location of the component's center of gravity must be taken into account. A component center of gravity is preferably located on the drive shaft axis, in particular in the tilting point of the swivel disk device (that is to say then in each case for each tilting angle).

From the relationships it can be seen that it is effective (exponent) to choose the geometry of the swivel plate device in such a way that the desired control behavior is achieved. It is particularly advantageous to provide a geometry of the swivel plate which represents a compromise between "low component mass" and (sufficient) "large mass moment of inertia".

When the swivel plate is designed as a swivel ring, this can be achieved in that both the inner diameter and the outer diameter are each designed to a maximum, taking into account the external environmental conditions, the external environmental conditions being predetermined by the size of the engine compartment and, for example, by the necessary sliding and Bearing surface for the sliding blocks of a joint arrangement between the swivel plate or swivel plate ring and the piston. The desired mass moment of inertia can also be influenced by a suitable choice of the swash plate thickness.

An exemplary embodiment of a swash plate engine according to the invention is explained in more detail below with reference to the attached drawing. This shows in:

Fig. 1 shows an embodiment of a swivel plate mechanism according to the invention for an axial piston compressor for vehicle air conditioning systems in a schematic perspective view, the swivel plate in a position for a maximum

Piston is located;

FIG. 2 shows the mechanism according to FIG. 1 in a schematic side view;

3 shows the swivel plate mechanism corresponding to FIGS. 1 and 2, partly in side view, partly in section;

4 shows the swivel plate mechanism corresponding to FIG. 3 in a side view;

Fig. 5 shows the mechanism of FIGS. 1-4 in a schematic

Perspective view, wherein the swivel plate is in a piston minimum stroke position; 6 shows the mechanism according to FIG. 5 in a side view;

7 shows the swivel plate mechanism according to FIGS. 5 and 6, partly in side view, partly in section;

8 the swivel plate mechanism according to FIG. 7 in

Side view;

Fig. 9 is a schematic representation of the coordinates of a

Swivel plate mechanism for calculating the moment of inertia; and

Fig. 10 part of a compound swivel ring in cross section and enlarged scale.

1-8 schematically shows a preferred embodiment of a swivel plate mechanism 100 for an axial piston compressor for motor vehicle air conditioning systems. This swivel plate mechanism 100 comprises a swivel plate 107 which is adjustable in its inclination to a drive shaft 104, rotatably driven by the drive shaft, in the present case ring-shaped swivel plate 107, both with a slide sleeve 108 mounted axially displaceably on the drive shaft 104 and with a spaced apart from it Drive shaft 104 is pivotally connected to this rotating support element 109. This articulated connection is designed as an axial support, as can be seen particularly well in FIGS. 2-4 and 5-8. The interaction of the swivel ring 107 with an axial piston which is distributed uniformly over a circumference extending around the drive shaft 104 and which is mounted to move back and forth within a cylinder block corresponds to that according to the prior art, for example according to DE 197 49 727 A1.

The pivot bearing of the pivot ring 107 defines a pivot axis 101 extending transversely to the drive shaft 104. This pivot axis 101 is specifically defined by two bearing pins mounted on both sides of the sliding sleeve 108 on the same axis. These bearing bolts are mounted in radial bores of the swivel ring 107. For this purpose, the sliding sleeve can additionally have bearing sleeves on both sides, which bridge the annular space between the sliding sleeve 108 and the swivel ring 107. This construction also largely corresponds to the prior art according to DE 197 49 727 AI.

Of importance is the axial support of the swivel ring on the support element 109 which rotates with the drive shaft 104. This support is provided by a support arch 110 arranged on the swivel ring 107. This support arch 110 is designed such that it engages over an articulated arrangement which is effective between the piston and the swivel ring, and This is so that, regardless of the inclination of the swivel ring 107, a collision between the latter and the support arch 110 on the one hand and a bridge-like piston foot comprising the aforementioned joint arrangement on the other hand is excluded. The support element 109 is an integral part of a disk 112 which rotates with the drive shaft 104, specifically a circular segment which is raised in relation to the disk.

The support surface of the arch 110 extends approximately concentrically to the center of the joint arrangement which is effective between the piston and the swivel plate or swivel ring 107 and which comprises sliding blocks in the form of spherical segments. The axial support is therefore effective outside the aforementioned joint arrangement, with the result that the joint arrangement, which is effective between the piston and the swivel plate or swivel ring, is not impaired by axial support measures. This applies in particular to the dimensioning of the aforementioned joint arrangement.

Furthermore, it can be seen that in the embodiment shown, the swivel bearing of the swivel plate or swivel ring 107 is used only for torque transmission and the support element 109 only for axial support of the pistons or gas force support. The torque transmission is therefore decoupled from the axial support of the swivel ring 107. 1-4, the swivel ring is in an inclined position for maximum piston stroke. 5-8 show the swivel ring in a position for a minimum piston stroke.

The circles drawn in FIGS. 4 and 8 in continuation of the support surface of the support arch 110 show that the support surface of the support arch 110 describes an arc. This can be deliberately deviated from if necessary in order to compensate for a predetermined “offset” of the support of the support arch 109 from the longitudinal axis of the piston when the inclination of the swivel ring 107 changes.

The support arch 110 can either be an integral component of the swivel ring 107 or, according to FIGS. 3 and 7, be rigidly connected to the swivel ring 107 as a separate component. The last-mentioned embodiment has the advantage that the swivel ring can be ground precisely on both flat sides, with the consequence of a correspondingly high parallelism of the two opposite running surfaces for the above-mentioned sliding blocks of an articulated arrangement which is effective between the piston and the swivel ring.

If the support arch 110 is also to be used for torque transmission, it preferably extends into a corresponding trough on the side of the support element 109 facing the support arch 110. The trough is then preferably designed as a radial groove.

At this point it should be pointed out again that the embodiment of a swivel plate mechanism shown is only an example. The concept according to the invention is, for example, just as suitable for a swivel plate or swivel ring mechanism according to DE 197 49 727 AI.

The swivel ring 107 is preferably balanced in such a way that the center of gravity lies in the so-called tipping point. For this purpose, a balance weight 114 can be provided relative to the drive shaft 104 diametrically to the support arch 110, as is shown only by way of example in FIG. 3. As already explained at the outset, the geometry and / or swivel plate or swivel ring 107 or the swivel path portion thereof is selected such that the centrifugal forces which occur when the swivel ring is rotated are sufficient to consciously counteract the swivel movement of the swivel ring and thus counteract the piston stroke and thus influencing the delivery rate, in particular reducing or limiting it.

In the embodiment shown, the swivel plate is designed as a swivel ring. In addition, it may be advantageous to provide moldings, bores, projections or the like for articulation to other components of the engine or for mass balancing. In any case, the center of gravity should preferably coincide with the tipping point (tilting joint) of the swivel ring.

The outside and inside diameters of the swivel ring 107 are determined by the diameter of the sliding blocks, which are part of a joint arrangement that is effective between the piston and the swivel ring. The aforementioned diameters are chosen so that the sliding blocks lie essentially on the flat sides of the swivel ring, in such a way that they protrude only slightly beyond the outer or inner diameter of the swivel ring even when the swivel ring is extremely inclined. In any case, under the given circumstances, both the inside and outside radius of the swivel ring should be maximum, the outside diameter of course also being limited by the inside diameter of the housing, which limits the engine room.

The above-mentioned support arch 110 is negligible in terms of its mass compared to the other parts of the swivel ring. It only has to be taken into account with regard to any imbalance, e.g. by arranging counterweights with compensatory effects.

The pistons used in the engine according to the invention have a mass of about 30 g to 90 g, preferably 35 g to 50 g. For this purpose, they consist of aluminum or an aluminum alloy (with or without plastic coating) or of a plastic composite. The use of steel, Cast steel or gray cast iron for the pistons is also conceivable. The consequence is, of course, that the piston masses increase. As a compromise, a combination of steel and aluminum is worth considering. A combination of metal and plastic is also conceivable.

As a rule, the inner radius “r” of the swivel ring 107 is in the range from 12 mm to 22 mm. The outer radius “r _a ” of the swivel ring 107 is approximately 34 mm to 42 mm.

The pistons lie on a pitch circle diameter "r _m " in the range between 24 mm and 34 mm.

A geometry in the range of “n = 20 mm”, “r _m = 29 mm” and “r _a = 38 mm” is preferred, where r _{m is} calculated from the equation r _m = (r _a + r _r ) / 2 ,

The height "h" of the swivel ring 107 is in the range from 8 mm to 20 mm, preferably in the range between 14 mm to 16 mm.

The material used for the production of the swivel ring 107 should preferably have a density of greater than 7 g / cm ³ , in particular greater than 8 g / cm ³ .

The swivel ring preferably consists of at least two materials in order to achieve optimal mass inertia. Such a compound swivel ring is shown schematically in FIGS. 3 and 7, the inner ring being identified by 107i and the outer ring by 107a. The outer ring 107a is preferably made of a higher density material. In this regard, FIG. 10 shows an alternative construction which is characterized in that the outer part ring 107a made of heavy material, ie material of higher density, such as lead or the like, is located within an outer circumferential groove 113 of the inner part ring 107i. which is made of wear-resistant steel, for example. This ensures that the two flat sides of the swivel ring, on which the sliding blocks of the piston linkage slide, are wear-resistant. Furthermore steel has a lower density than lead, ie the inner part ring 107i consists of a lighter material than the outer part ring 107a.

The swivel ring 107 preferably has a mass moment of inertia J ₂ = Jη or J = m / 4 (r _a ² + n ² + h ^2/3 ), which is greater than 100,000 gmm ² . The moment of inertia is preferably greater than J = 200,000-250,000 gmm ² .

Furthermore, the swivel ring preferably has a mass moment of inertia of J ₃ = J _{ζ =} -

2

(r _a ² + n ² ), which is larger than 200,000 gmm ² , preferably about 400,000 - 500,000 gmm ² .

(Note: As a rule (disc or ring), J _{δ is} always approximately J ₃ = 2 x J _{2. However} , it primarily depends on J ₃ , although J ₂ and J ₃ are interdependent as described.)

As explained above, there are various influencing variables (moments) that affect the control behavior of the swivel plate or swivel ring. It is important to compensate for the moment due to translational masses directly or, if necessary, to overcompensate for the moment due to rotating masses.

The derivation of the so-called deviation torque is given below, which is decisive for the tilting of the swivel plate or a swivel ring, and in the case shown is solely responsible for the tilting of the swivel plate or swivel ring, provided that the center of gravity of the swivel plate or . of the swivel ring lies both in the tipping point and in the geometric center of the swivel plate or swivel ring. This is an ideal design case to be aimed for. The following generally applies to the derivation of the moment of deviation with reference to FIG. 9:

J _yz = -JιCθsα ₂ cosα ₃ - J ₂ cosß ₂ cosß ₃ -J ₃ cosγ ₂ cosγ ₃ αι = 0 ßi = 90 ° L directional angle of the x-axis γi = 90 °) with respect to the main axes of inertia ξ-η-ζ α ₂ = 90 ° ß ₂ = ψ directional angle of the y-axis compared to γ ₂ = 90 ° + ψ main axes of inertia ξ-η'ζ

Direction angle of the z-axis compared to the

Main axes of inertia ξ-η-ζ

mh = Jς = -i (r _a ² + r, ² )

(Note: J ₃ «2 J ₂ goal: J _yz should have a certain size Jyz f J ₂ inevitably increases!)

of inertia

J _yz = -J ₂ cosψ sinψ + J ₃ cosψ sinψ

For the rest, regardless of Fig. 9:

Torque due to the mass force of the pistons ß, = θ + 2π (i-1) - n

Zi = R ^• ω ² tan cosß,

F _ml = m _k 'Zj

M (F _mi ) = m _k ^■ R ^• cosßi ^■ z,

M _kιges = m _k ^■ R ∑z _\ ^• cosßi ι = l

Moment due to deviation moment Msw M _sw = J _yz ^* ω ²

, msw. , .. msw. ,,, h ² _η Jyz = {- ( ^r a ² + n ² ) - -j- ("^{" 2} + n ² + -)} cosα sinα

msw

Jyz = sin2α (3r _a ² + 3η ² - h ² ) ^~ 2 ^~ The sizes used above mean what follows:

θ angle of rotation of the shaft (whereby the above and following considerations are made for θ = 0 for the sake of simplicity) η number of pistons

R Distance between the piston axis and the shaft axis ω Shaft speed α Tilt angle of the swivel ring / swivel plate mk Mass of a piston including sliding blocks or pair of sliding blocks mk, total Mass of all pistons including sliding blocks msw Mass of the swivel ring ra External radius of the swivel ring ri Inner radius of the swivel ring h Height of the swivel ring Density of the swivel ring

V volume of the swivel ring ßi angular position of the piston i zi acceleration of the piston i

Fmi mass force of the piston i (including a pair of sliding blocks) M (Fmi) moment due to the mass force of the piston i

Mk, total moment due to the mass force of all pistons

Msw moment due to the set-up torque of the swivel ring / swash plate (deviation torque)

It is the aim of the present invention that the moment due to the moment of installation of the swivel plate or the swivel ring, i.e. the moment of deviation is greater than / equal to the moment due to the mass forces of all pistons, i.e. the following relationship applies:

M _sw > Mk, tot or

[ω ² - sin2α (3r _a ² + 3r, ² -h ² )> ω ² R ² m _k tanα ∑ cos ² ßi]

24 _{/ = 1} The aforementioned equation shows that the speed has the same influence on both terms and therefore changes in speed do not change the torque ratio. This also results from the following example in Tables 1 and 2, where:

Number of pistons: n = 7

Distance between piston axis and drive shaft longitudinal axis: R = 25 mm

Inner radius r, / outer radius r _{a of} the swivel ring: n / r _a = 15/35

Density: S = 7.9

Swivel ring height: h = 10 mm

Mass / piston: m _k = 39 assuming:

Table 1

Table 2

Table 2 shows that the respective swivel plate or ring tilt angle changes only slightly at the torque ratio. Furthermore, it follows from the above equation that tanα ≠ sin2α, and accordingly the torque ratio, in particular for small angles α, depends little on the angle α. This results in a sensible design for an average angle α: M _k , _tot = M _s or for α _max : M _k , _tot = M _sw . The swivel plate has a compensating effect.

Table 3 below shows results for the case: - Swivel plate has a compensating effect - Swivel plate has a regulating or overcompensating function

Table 3

Influence of the swash plate geometry Q = 7.9 g / mnV ra ri h Jy / mk, ges Jy / msw Jz / mk, ges Jz / msw msw / mk, ges Mk, ges Msw

35.00 15.00 10.00 337 371 659 725 0.91 1.48 1.48 compensating

37.50 17.50 10.00 436 436 856 856 1.00 1.80 1.93 compensating (~)

40.00 20.00 10.00 555 508 1091 1000 1.09 2.14 2.47 compensating (~)

ra ri h Jy / mk, tot Jy / msw Jz / mk, tot Jz / msw msw / mk, tot Mk, tot Msw

35.00 15.00 16.00 558 384 1055 725 1.45 1.48 2.29 regulating

37.50 17.50 16.00 719 449 1370 856 1.60 1.80 3.00 regulating

40.00 20.00 16.00 910 521 1745 1000 1.75 2.14 3.85 regulating

where "(~)" means something like "about" or "about".

For the moment equilibrium, only the geometrical quantities are relevant, whereby the masses of the pistons and the swivel plate naturally also have an influence. The following parameters are of relevance to the moment balance:

[m _k , _tot / msw / R ² / r _a ² / r, ² / h ² ] When the swivel plate is designed as a swivel ring, it is useful to determine the distance between the piston axis and the drive shaft axis from the relationship

R = (r _a + r,) / 2

to calculate.

For an optimal design of the swivel plate, here the swivel ring 107, one preferably refers to the quotient “moment of inertia / mass”, that is to say “J / m”. This quotient expresses the magnitude of the moment of inertia for a predetermined swivel plate or swivel ring mass. The quotient should be greater than 250 gmm ² / g. Quotients of greater than 400-500 gmm ² / g are particularly advantageous. "J" refers to each center of gravity axis (thus: J = J _x = J ₂ = J ₃ , where J ₃ »2J ₂ generally applies), the center of gravity of the rotating mass preferably being in the center of the tilting joint thereof.

Larger mass inertias are to be selected in particular if piston masses significantly larger than 40 g / piston are selected.

Above all, the construction according to the invention is intended to mechanically limit the delivery rate of an axial piston compressor when the speed is increased. The ideal case would, of course, be a constant control, the constant control being a sub-case of the mechanical limitation aimed at according to the invention caused by geometry and torque distribution.

The example below shows an advantageous design with different radii, volumes and masses for a swivel ring 107: Table 4

The above values result from the following generally valid equations for a swivel ring:

(1) m = ς V

(2) V = - / * (D ² -d ² ) 4 (3) D = 2r _a

(4) d = 2r,

(5) J = m / 4 (r _a ² + r, ² + h ^2/3 )

As explained, the design preferably refers to the quotient "J / m" in general, and preferably specifically to the ratio "J _y / m _k , _tot ", that is, to the quotient from the inertia of the swivel plate or swivel ring in the Reference to the y-axis according to FIG. 9 and the total piston masses. This quotient can be used as an alternative to the aforementioned measures or in parallel to the design of the construction and thus to achieve a desired control behavior.

It can be assumed that a ratio of rotating to translatory masses m _sw / m _k , _tot of significantly less than “1” is very disadvantageous the desired control behavior affects here. The aforementioned relationship must therefore be avoided.

With a mass ratio of m _sw / m, g _e s = 1, a minimum value for compensation of approximately 250 to 300 g mm ² / g is preferably obtained for the ratio Jy / m, _ges .

Larger values can be set depending on the desired control behavior; In particular, however, an exact compensation of changes in the swivel _plate tilt angle with a mass ratio of m _ktges = m _{sw is} of interest.

Overcompensation can also be of interest, especially when compensating for the change in delivery rate due to speed changes.

Similarly, the quotients J _z / m _k , _ges and J _z / m _{sw could also be used} for the design of the desired control behavior, since the moment of inertia J _z in relation to the z or drive shaft axis together with J _{y is} the relevant deviation torque forms. The following applies to the swivel ring geometry shown:

J ₂ «2 J _v

Since J _y2 «J _z (...) - Jy (...), and since J _yz is supposed to be large, J _{2 is} actually the more important quantity. J _y can only be used as a reference value because the above relationship J _z ∞2 J _y applies.

All features disclosed in the application documents are claimed as essential to the invention, insofar as they are new compared to the prior art, individually or in combination. Reference sign

100 swivel plate mechanism 101 swivel bearing (swivel axis)

104 drive shaft

107 swivel ring

107i inner swivel ring

107a outer swivel ring 108 sliding sleeve

109 support element (axial support)

110 support arch

112 disc

113 circumferential groove 114 counterweight

Claims

1. Axial piston compressor, in particular a compressor for the air conditioning system of a motor vehicle, with a housing and a compressor unit arranged in the housing and driven via a drive shaft (104) for the suction and compression of a refrigerant, the compressor unit in a cylinder block and axially reciprocating pistons and comprises a swivel plate (107) which drives the pistons and rotates with the drive shaft (104), since you can see that at a predetermined rotatably moved mass of the swivel plate (107) on the one hand and / or a certain translationally moved mass (for example

Piston, piston rod and / or sliding blocks), on the other hand, the mean radius determined by the geometry and / or density distribution and / or the mean height of the swivel plate (107) or the swiveling portion thereof is selected such that the rotation of the swivel plate (107) centrifugal forces that occur are sufficient to consciously counteract the pivoting movement of the pivoting disk (107) and thus to influence, in particular to reduce or limit, the piston stroke and thus the delivery rate.

2. Axial piston compressor according to claim 1, since you rch g eken nzeich n et that the swash plate is a swivel ring (107).

3. Axial piston compressor according to claim 1 or 2, d ad u rch g eke n nze n et that the quotient moment of inertia / mass "J / m" of the swash plate (107) or the swiveling portion thereof at least about 250 gmm / g , in particular greater than 400 to 500 gmm ² / g, higher values being selected if the piston masses are greater than 40 g / piston, and the moment of inertia “J” with respect to each axis being determined by the center of gravity of the swivel plate or pivotable portion of the same is calculated.

4. axial piston compressor according to claim 3, d ad u rch g eke n nzei ch net, since the swash plate or the swiveling portion thereof is made of a material with a density of at least 6-8 g / cm ³ .

5. Axial piston compressor according to one of claims 1-4, d ad u rch g eken nzei ch n et, since ss the swash plate (107) or the pivotable portion thereof from two or more different, determining the mean radius for calculating the moment of inertia Materials is produced, the different materials being separated radially and / or axially from one another, in particular in such a way that in the case of a swivel ring (167) an outer (107a) or inner partial ring made of a first material (107i), for example Higher density material, such as lead or the like, is formed within an outer (113) or inner circumferential groove of an inner (107i) or outer partial ring, which is made of harder and wear-resistant material, e.g. Steel, ceramics or the like is made.

6. Axial piston compressor according to one of claims 1-5, d ad u rch g eke n nze n et that the swash plate (107) or the pivotable portion thereof with respect to each axis of gravity, a mass moment of inertia "J" of greater than 100,000 g / mm ² , in particular greater than 200,000 to 250,000 g / mm ² .

7. axial piston compressor according to one of claims 1-6, d a d u rc h g eke nze I net, that the pistons each have a mass of about 30 g to 90 g, in particular 35 g to 50 g.

8. Axial piston compressor according to one of claims 1-7, so that the average radius and / or the average height of the swivel plate or the swiveling portion thereof are dimensioned such that the rotation of the swivel plate (107) occurring, the pivoting movement of the swashplate

(107) counteracting centrifugal forces are above the forces acting on the swashplate on the part of the pistons, which cause a more extensive swiveling movement, so that the piston stroke decreases with increasing speed to such an extent that an approximately constant delivery rate is established.

9. axial piston compressor according to one of claims 1-8, dadu rch g eken nzeich net, since ss the center of gravity of the swash plate (107) or the pivotable portion thereof in, or at least near the axis of the drive shaft (104), where in particular also the center of the tilt joint is located.

10. Axial piston compressor according to any one of claims 5-9, dadu rch g eke nze i ch net, since the radially outer parts (107a) of denser when forming the swash plate (107) or the pivotable portion thereof from a plurality of materials of different densities Material than the radially inner parts (107i).

11. Axial piston compressor according to one of claims 2-10, dad u rch geken nzeich net that when the swash plate is designed as a swivel ring (107) the inside and outside diameter within the outside conditions (for example inside diameter of the engine compartment, sufficient support for the Sliding stones of a joint arrangement effective between the piston and the swivel plate, etc.) are selected as maximum.

12. Axial piston compressor according to one of claims 5-11, dadu rch ge ken nzeich n et, that when forming the swash plate from at least two materials of different densities, the one material has a density of 6-8 g / cm ³ , while the other material has a density of more than 6-8 g / cm ³ .

13. Axial piston compressor according to one of claims 1-12, dadu rch ge ken nze net, since ss the quotient M _sw / M _{k (} g _es > 1, where M _{sw is} the moment due to the moment of _{variation of} the _{swash plate} and M _kges the moment due to the inertial forces of the translationally moved masses (pistons).

14. Axial piston compressor according to any one of claims 1-13, dad u rch ge ken nzeich net, d ass the quotient of the inertia of the swash plate with respect to the y-axis, ie an axis perpendicular to the z or drive shaft axis and total piston mass "J _y / m _k , _ge s" is at least about 250-300 g mm ² / g for the case that m _sw / m _k , ges = 1, where: m _s = mass of the swash plate (= rotating mass) m _k , g _es = mass of all pistons including sliding blocks (= translational mass)

15. Axial piston compressor according to one of claims 2-14, dad u rch geken nzei chnet that the distance "R" between the piston axis and drive shaft axis is derived from the relationship

R = (r _a + r,) / 2 results, where r _a = outer radius of the swivel ring (107), and r, = inner radius of the swivel ring (107).