EP1636492B1 - Axial piston compressor, particularly a compressor for the air-conditioning system of a motor vehicle - Google Patents

Description

The invention relates to an axial piston compressor, in particular a compressor for the air conditioning of a motor vehicle, comprising a housing and a housing arranged in the housing, driven by a drive shaft compressor unit for sucking and compressing a refrigerant, wherein the compressor unit in a cylinder block axially reciprocating piston and a the piston driving, rotating with the drive shaft swash plate comprises.

Such Axialkolbenverdichter is for example from the DE 197 49 727 A1 known. This includes a housing in which a plurality of axial pistons are arranged around a rotating drive shaft in a circular arrangement. The driving force is transmitted from the drive shaft via a driver on an annular pivot plate and from this in turn to the parallel to the drive shaft translationally displaceable piston. The annular swash plate is pivotally mounted on a sleeve mounted axially displaceably on the drive shaft. In the sleeve, a slot is provided through which engages the mentioned driver. Thus, the axial mobility of the sleeve on the drive shaft is limited by the dimensions of the elongated hole. An assembly takes place by a passing through the driver through the slot. Drive shaft, driver, sliding sleeve and swivel disk are arranged in a so-called. Engine room, in which gaseous working fluid of the compressor is present at a certain pressure. The delivery volume and thus the delivery rate of the compressor depend on the pressure ratio between the intake side and the delivery side of the piston or correspondingly depending on the pressures in the cylinders on the one hand and in the engine room on the other.

A slightly different type of axial piston compressor is for example in the DE 198 39 914 A1 described. The swash plate is designed as a swash plate, wherein between the swash plate and the piston mounted opposite the swash plate, rotatable receiving disc is arranged.

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

Furthermore, reference is made to the following prior art:

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

The compressors described in these publications are u.a. to take measures to prevent or reduce the imbalance of the engine during operation. Incidentally, the known constructions in common that the rotating components relative to the translationally moving parts, namely piston, piston rod, etc. are relatively large and therefore heavy built. Furthermore, the known constructions have in common that acts on the actual swash plate device an additional disc by a suitable coupling mechanism. The plurality of rotating components are intended to cause a Aufstellendes moment of the swash plate device in the direction of minimum stroke, which affects the control behavior is taken.

The mentioned embodiments are all relatively expensive, expensive, not very compact and therefore unsuitable for today by the automotive industry required compressors for air conditioning.

Even with series compressors, as they are used in motor vehicles today, one aims at a suitable dimensioning of the moving components or moving Masses to achieve a desired control behavior, to the effect that the centrifugal forces occurring when turning the swash plate sufficient to deliberately counteract the pivotal movement and thus to influence the piston stroke and thus the flow rate, in particular to reduce or limit. For example, the DENSO 6SEU12C series compressor features an engine with the following masses relevant for control behavior: component number Mass component [g] Total mass [g] piston 6 41 246 slide 12 5 60 translationally moving masses 306 g swash plate 1 391 391 guide pins 2 20 40 rotationally moving masses 431 g

The above numbers indicate that a considerable component mass is provided for parts that move in rotation. This is an attempt to produce a sufficient counterforce or a sufficient counter-torque with respect to the translationally moving masses. This basic idea lies also the DE 198 39 914 A1 based, where just the rotating mass of the swash plate or the pivotal portion of the same is dimensioned such that the centrifugal forces occurring when turning the drive pulley deliberately counteract the pivotal movement of the swash plate regulatory and thus to influence the piston stroke and thus the flow rate, namely reduce or limit or in particular to keep constant.

• Moment infolge der Gaskräfte in den Zylinderräumen (+)
• Moment infolge der Gaskräfte aus dem Triebwerksraum (-)
• Moment infolge einer Rückstellfeder (-)
• Moment infolge einer Aufstellfeder (+)
• Moment infolge rotierender Massen (-); inklusive Moment infolge Schwerpunktlage (z.B. Schwenkscheibe: Kippposition ≠ Massenschwerpunkt): kann (+) sein
• Moment infolge der translatorisch bewegten Massen (+)

In 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, the influencing variables are shown, which act as moments around the tilting center of a swashplate device , These are in detail the following moments, in brackets in each case the direction of Moments is given and (-) offsetting (in the direction of a minimum lift) and (+) upward (in the direction of the maximum lift) mean:

• Moment due to gas forces in the cylinder chambers (+)
• Moment due to the gas forces from the engine room (-)
• Moment due to a return spring (-)
• Moment due to an upright spring (+)
• Moment due to rotating masses (-); including moment due to center of gravity (eg swashplate: tilting position ≠ center of gravity): can be (+)
• Moment due to translationally moving masses (+)

With respect to the mentioned compressor 6SEU12C DENSO, which represents the typical design of a swash plate compressor, it should be noted that the mass of such a swash plate can not be increased arbitrarily in order to change the control behavior with it. This is because in the compressors of the type described the center of gravity of the swash plate usually has a significant distance from the tilting joint of the swash plate. This construction is essentially based on the fact that the swash plate must be coupled in addition to a suitable guide on the drive shaft via an adjusting mechanism with the drive shaft or a component connected to the drive shaft.

The mentioned distance from the center of gravity of the swash plate and the tilting joint thereof leads to an imbalance of the engine, in particular as a function of the swashplate tilt angle, and in the worst case leads to an uplifting property (see also "center of gravity").

Thus, in the compressors of the prior art; and to make a compromise in both the written and actually practiced prior art in that a predetermined mass of the swashplate is provided to counteract the translationally moved masses manufacture. On the other hand, the mass of the swash plate may not be designed too large, because then the imbalance of the engine would be excessive.

In order to address this problem, it has also been proposed to use the pistons, i. the translational masses as low as possible, i. easy to build, for example made of aluminum or other materials with a lower specific gravity. There is also the suggestion to use hollow piston in this regard.

But even with these measures, in particular a constant control of the flow rate at different speeds can not be achieved. It should be noted that the term "constant regulation" is not to be understood as an exact statement. In fact, the delivery rate would only be exactly constant if, for example, the tilting angle of the swashplate device halved when the rotational speed doubled. To be considered, however, that also other parameters act on the flow rate, such as degree of delivery or oil throw od. Like., If, for example, the tilt angle of the swash plate changes.

For a constant control of the flow rate at varying speeds, the restoring torque of the swash plate device is utilized because - as already explained - the swash plate counteracts their inclination due to the dynamic forces on the co-rotating disc part.

This behavior can be assisted by spring forces or hydraulically, pneumatically or the like, so that, as the rotational speed increases, increasing flow rate is at least partially compensated by resetting the inclination.

The case of a compensation of the up and down regulating moment can also be very interesting. Speed changes then do not intervene in the regulation. This can be worked with a simpler control algorithm.

As already stated above, such a behavior can in principle be achieved by, for example, integrating an additional mass into the engine, whose Inertia, as described, via a coupling mechanism on the swash plate device affects.

However, it has also been stated that the mass of the swash plate can not be increased arbitrarily, without other disadvantages must be taken into account. This applies in particular to the teaching according to the DE 198 39 914 A1 respectively. EP 99 953 619 (Application no.). The proposed there regulation with the mass of the rotating components can lead to a control behavior, through which the flow rate is largely independent of speed. However, this is not inevitable. It can also lead to overcompensation. The design criteria are blurred. The reason for this is that the mass of the rotating components only proportionally influences the installation torque of the swashplate.

The present invention is therefore an object of the invention to provide a compressor of the type mentioned, which optionally has a control behavior of the compensation, overcompensation, constant control for the "flow rate", with a minimum mass of pivoting rotary components, so that a Compact design of the compressor is possible.

This object is achieved by the characterizing features of claim 1, wherein preferred structural details and developments are described in the dependent claims.

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

A core idea of the invention is thus to compensate for the moment as a result of translational masses directly by the moment due to rotating masses, or to overcompensate.

The set-up torque which is to be produced on a swash plate device is a function of the rotational speed or the angular velocity ω and the mass moment of inertia J of the swivel plate device: $$\mathrm{M}\mathrm{=}\mathrm{f}\left({\mathrm{\omega }}^{\mathrm{2}}\mathrm{;}\mathrm{J}\right)$$

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": $$\mathrm{J}\mathrm{=}\mathrm{f}\left(\mathrm{m},,{\mathrm{r}}^{\mathrm{2}},,{\mathrm{H}}^2\right)$$

wobei δ = Dichte,
r = Schwenkscheibenradius, und
h = Schwenkscheibenhöhe bedeuten.Expressed more precisely, the mass moment of inertia is essentially a function of the component density distribution and also of the component geometry. The component density distribution, for example, takes account of swivel disks made of different materials, namely 2, 3 or more materials or a material with a different density distribution (metal foam, heterogeneous material): $$\mathrm{J}\mathrm{=}\mathrm{f}\left(\mathrm{\delta },,{\mathrm{r}}^{\mathrm{2}},,{\mathrm{H}}^2\right).$$

where δ = density,
r = swashplate radius, and
h = mean swashplate height.

In addition, the position of the component center of gravity must be taken into account. Preferably, a component center of gravity will lie on the drive shaft axis, in particular in the tilting point of the swivel disk device (ie in each case for each tilt angle).

It can be seen from the contexts that it is effective (exponent) to select the geometry of the swivel disk device in such a way that the desired control behavior is achieved.

It is particularly advantageous to provide a geometry of the swashplate which represents a compromise between "low component mass" and (sufficiently) "large mass moment of inertia".

In forming the swash plate as a swivel ring, this can be achieved in that both the inner diameter and the outer diameter are formed taking into account the external environmental conditions each maximum, the external environmental conditions are dictated by the size of the engine room and, for example, by the necessary sliding and Bearing surface for the sliding blocks of a joint arrangement between the swash plate or swash plate ring and piston. Also influence can be taken on the desired moment of inertia by a suitable choice of the swash plate thickness.

Fig. 1

eine Ausführungsform eines erfindungsgemäßen Schwenkscheiben-Mechanismus für einen Axialkolbenverdichter für Fahrzeug-Klimaanlagen in schematischer Perspektivansicht, wobei die Schwenkscheibe sich in einer Stellung für einen maximalen Kolben befindet;

Fig. 2

den Mechanismus gemäß Fig. 1 in schematischer Seitenansicht;

Fig. 3

den Schwenkscheiben-Mechanismus entsprechend den Fig. 1 und 2, teilweise in Seitenansicht, teilweise im Schnitt;

Fig. 4

den Schwenkscheiben-Mechanismus entsprechend Fig. 3 in Seitenansicht;

Fig. 5

den Mechanismus gemäß Fig. 1-4 in schematischer Perspektivansicht, wobei sich die Schwenkscheibe in einer Kolben-Minimalhub-Stellung befindet;

Fig. 6

den Mechanismus gemäß Fig. 5 in Seitenansicht;

Fig. 7

den Schwenkscheiben-Mechanismus gemäß den Fig. 5 und 6, teilweise in Seitenansicht, teilweise im Schnitt;

Fig. 8

den Schwenkscheiben-Mechanismus gemäß Fig. 7 in Seitenansicht;

Fig. 9

eine schematische Darstellung der Koordinaten eines Schwenkscheiben-Mechanismus zur Berechnung des Massenträgheitsmomentes; und

Fig. 10

Teil eines Compound-Schwenkringes im Querschnitt und vergrößertem Maßstab.

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

Fig. 1

an embodiment of a swash plate mechanism according to the invention for an axial piston compressor for vehicle air conditioning systems in a schematic perspective view, wherein the swash plate is in a position for a maximum piston;

Fig. 2

according to the mechanism Fig. 1 in a schematic side view;

Fig. 3

the swash plate mechanism according to the Fig. 1 and 2 partly in side view, partly in section;

Fig. 4

the swash plate mechanism accordingly Fig. 3 in side view;

Fig. 5

according to the mechanism Fig. 1-4 in a schematic perspective view, wherein the swash plate is in a piston-minimum stroke position;

Fig. 6

according to the mechanism Fig. 5 in side view;

Fig. 7

the swash plate mechanism according to the Fig. 5 and 6 partly in side view, partly in section;

Fig. 8

the swashplate mechanism according to Fig. 7 in side view;

Fig. 9

a schematic representation of the coordinates of a swash plate mechanism for calculating the mass moment of inertia; and

Fig. 10

Part of a compound swivel ring in cross-section and enlarged scale.

In the Fig. 1-8 A preferred embodiment of a swashplate mechanism 100 for an axial piston compressor for automotive air conditioning systems is shown schematically. This swashplate mechanism 100 includes an adjustable in its inclination to a drive shaft 104, rotationally driven by the drive shaft, in the present case annular swash plate 107, which both with an axially slidably mounted on the drive shaft 104 sliding sleeve 108 and with a distance from the Drive shaft 104 is pivotally connected to this co-rotating support member 109. This articulated connection is designed as Axialabstützung, in particular the Figures 2-4 and 5 -8th very good. The interaction of the pivot ring 107 with evenly distributed over a circumferentially extending around the drive shaft 104 around arranged axial piston, which are reciprocally mounted within a cylinder block, corresponds to that of the prior art, for example according to the 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 concretely defined by two coaxially mounted on both sides of the sliding sleeve 108 bearing pin. These bearing pins are mounted radial bores of the pivot ring 107. The sliding sleeve can for this purpose on both sides additionally bearing sleeves, which bridge the annulus between the sliding sleeve 108 and the pivot ring 107. Also, this construction largely corresponds to the prior art according to the DE 197 49 727 A1 ,

Of importance is the axial support of the pivot ring on the co-rotating with the drive shaft 104 supporting element 109. This support is provided by a pivot ring 107 arranged on the support sheet 110. This support arc 110 is formed so that it engages over an effective between piston and pivot ring assembly, and Although so that regardless of the inclination of the pivot ring 107, a collision between this and the support sheet 110 on the one hand and the aforementioned joint assembly comprehensive bridge-like piston foot on the other hand is excluded. The support member 109 is an integral part of a co-rotating with the drive shaft 104 disc 112, and that a raised relative to the disc formed circular segment.

The support surface of the arc 110 extends approximately concentric with the center of the effective between the piston and swash plate or pivot ring 107 hinge assembly comprising spherical segment-shaped sliding blocks. The axial support is therefore effective outside of the aforementioned joint arrangement, with the result that the joint arrangement, which is effective between the piston and swivel disk 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 serve in the illustrated embodiment, the pivot bearing of the swash plate or the swivel ring 107 only for torque transmission and the support member 109 only for axial support of the piston or gas force support. The torque transmission is thus decoupled from the axial support of the pivot ring 107.

In the Fig. 1-4 the swivel ring is in a tilt position for maximum piston stroke. The Fig. 5-8 show the swivel ring in a position for a minimum piston stroke.

The in the Fig. 4 and 8th drawn circles in continuation of the support surface of the support arc 110 show that the support surface of the support arc 110 describes a circular arc. Of these, if necessary, deviated conscious to compensate for a predetermined "offset" of the support of the support sheet 109 of the piston longitudinal axis with change in the inclination of the pivot ring 107.

The support sheet 110 may be either integral part of the pivot ring 107 or according to the Fig. 3 and 7 be rigidly connected as a separate component with the pivot ring 107. The latter embodiment has the advantage that the pivot ring on both flat sides can be precisely grinded with the result of a correspondingly high parallelism of the two opposite treads for the above-mentioned sliding blocks effective between the piston and pivot ring hinge assembly.

If the support arch 110 is also intended to transmit torque, this preferably extends into a corresponding recess on the side of the support element 109 facing the support arch 110. The trough is then preferably designed as a radial groove.

It should be noted at this point again that the illustrated embodiment of a swash plate mechanism is only exemplary. The inventive concept is for example just as well for a Schwenkscheiben- or swivel ring mechanism according to the DE 197 49 727 A1 ,

Preferably, the pivot ring 107 is balanced, in such a way that the focus is in the so-called. Tipping point. For this purpose may be provided relative to the drive shaft 104 diametrically to the support sheet 110 is still a balance weight 114, as only exemplified in Fig. 3 is drawn.

As already stated at the outset, the average radius determined by the geometry and / or density distribution and / or the average height of the swash plate or swivel ring 107 or swiveling portion thereof is selected such that the centrifugal forces occurring when the swivel ring is rotated are sufficient counteract the pivotal movement of the pivot ring deliberately regulatory and thus to influence the piston stroke and thus the flow rate, in particular to reduce or limit.

In the illustrated embodiment, the swash plate is designed as a swivel ring. In addition, it may be advantageous to provide for a linkage to other components of the engine or for mass balancing formations, holes, protrusions od. Like. In any case, preferably the center of mass should coincide with the tilt point (tilting joint) of the pivot ring.

Outer and inner diameter of the pivot ring 107 are determined by the diameter of the sliding blocks, which are part of an effective between piston and swivel ring hinge assembly. The aforementioned diameter are chosen so that the sliding blocks rest substantially on the flat sides of the pivot ring, in such a way that they protrude only slightly beyond the outer or inner diameter of the pivot ring, even with extreme inclination of the pivot ring. In any case, under the given circumstances, both inner and outer radius of the swivel ring should be maximum, wherein the outer diameter is of course also limited by the inner diameter of the housing, which limits the engine room.

The aforementioned support arc 110 is negligible in terms of its mass compared to the other parts of the pivot ring. It only needs to be considered with regard to any imbalances, e.g. by arrangement of compensatory counterweights.

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. They consist of aluminum or an aluminum alloy (with or without plastic coating) or a plastic composite for this purpose. The use of steel, Cast steel or cast iron for the pistons is also conceivable. The consequence is of course that the piston masses get bigger. As a compromise, a combination of steel and aluminum is worth considering. Also conceivable is a combination of metal and plastic.

In general, the inner radius "r _i " of the pivot ring 107 is in the range of 12 mm to 22 mm. The outer radius "r _a " of the pivot ring 107 is about 34 mm to 42 mm.

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

Preference is given to a geometry in the range of "r _i = 20 mm", "r _m = 29 mm" and "r _a = 38 mm", where r _m from the equation r _m = (r _a + r _i ) / 2 calculated.

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

The material which is 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 .

Preferably, the pivot ring consists of at least two materials to achieve an optimal inertia. In Fig. 3 and 7 Such a compound swivel ring is shown schematically, wherein the inner ring with 107i and the outer ring is labeled 107a. The outer ring 107a is preferably made of a material of higher density. In Fig. 10 In this regard, an alternative construction is shown, which is characterized in that the outer part ring 107a of heavy material, ie, higher density material such as lead od. Like. Within an outer circumferential groove 113 of the inner part ring 107i is made, for example, made of wear-resistant steel is. This ensures that the two flat sides of the swivel ring, on which slide the sliding blocks of Kolbenanlenkung, are wear-resistant. Furthermore Steel has a lower density than lead, ie, the inner part ring 107i is made of a lighter material than the outer part ring 107a.

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

(r_a ² + r_i ²), das größer ist als 200.000 gmm², vorzugsweise etwa 400.000 - 500.000 gmm².
(Anmerkung: In der Regel (Scheibe oder Ring) ist J_δ immer ungefähr J₃ = 2 × J₂. Es kommt aber primär auf J₃ an, wobei J₂ und J₃ jedoch wie beschrieben, voneinander abhängig sind.)Next, the pivot ring preferably has a moment of inertia of ${\mathrm{J}}_{\mathrm{3}}\mathrm{=}{\mathrm{J}}_{\mathrm{\zeta }}=\frac{m}{2}$

(r _a ² + r _i ² ), which is greater than 200,000 gmm ² , preferably about 400,000 - 500,000 gmm ² .
( Note: Usually (disc or ring), J _{δ is} always approximately J ₃ = 2 × J ₂ , but J ₃ is the prime choice, but J ₂ and J ₃ are interdependent as described.)

As explained above, there are various influencing variables (moments) which intervene in the control behavior of the swash plate or swivel ring. It is important to compensate for the moment due to translational masses directly by the moment due to rotating masses or possibly overcompensate.

$${\mathrm{J}}_2\mathrm{=}{\mathrm{J}}_{\mathrm{\eta }}=\frac{m}{4}\left({{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}+\frac{h^2}{3}\right)$$

$${\mathrm{J}}_3\mathrm{=}{\mathrm{J}}_{\mathrm{\zeta }}=\frac{m}{2}\left({{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}\right)$$

(Anmerkung: J₃ ≈ 2 J₂
Ziel: J_yz soll eine bestimmte Größe haben
J_yz ↑} J₃ ↑ J₂ erhöht sich zwangsläufig!)Below is the derivation of the so-called. Deviationsomomentes specified, which is relevant for the tilting of the swash plate or a swivel ring, and in the case shown solely for the tilting of the swash plate or the swivel ring is responsible under the condition that the center of gravity of the swash plate or of the pivot ring is located both in the tilting point and in the geometric center of the swash plate or the swivel ring. This is a desirable ideal case of construction. For the derivation of the moment of deviation applies in general with reference to Fig. 9 : $${\mathrm{J}}_{\mathrm{Y\; Z}}\mathrm{=}\mathrm{-}{\mathrm{<figure-callout\; id="1"\; label="J"\; filenames="imgf0006.png"\; state="\{\{state\}\}">J</figure-callout>}}_{\mathrm{1}}{\cos }_{\mathrm{2}}{\cos }_{\mathrm{3}}\mathrm{-}{\mathrm{J}}_{\mathrm{2}}{\mathrm{cos\beta }}_{\mathrm{2}}{\mathrm{cos\beta }}_{\mathrm{3}}\mathrm{-}{\mathrm{J}}_{\mathrm{3}}{\mathrm{cos\gamma }}_{\mathrm{2}}{\mathrm{cos\gamma }}_{\mathrm{3}}$$

$${\mathrm{J}}_2\mathrm{=}{\mathrm{J}}_{\mathrm{\eta }}=\frac{m}{4}\left({{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}+\frac{H^2}{3}\right)$$

$${\mathrm{J}}_3\mathrm{=}{\mathrm{J}}_{\mathrm{\zeta }}=\frac{m}{2}\left({{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}\right)$$

(Note: J ₃ ≈ 2 J ₂
Goal: J _yz should have a certain size
J _yz ↑} J ₃ ↑ J ₂ inevitably increases!)

of inertia $${\mathrm{J}}_{\mathrm{Y\; Z}}\mathrm{=}\mathrm{-}{\mathrm{J}}_{\mathrm{2}}\mathrm{cos\psi \; sin\psi }\mathrm{+}{\mathrm{J}}_{\mathrm{3}}\mathrm{cos\psi \; sin\psi }$$

Otherwise, regardless of Fig. 9 :

Moment due to inertia of the pistons

$${\mathrm{\beta }}_{\mathrm{i}}\mathrm{=}\mathrm{\theta }\mathrm{+}\mathrm{2}\mathrm{\pi }\left(\mathrm{i}-1\right)\frac{1}{n}$$

$$\mathrm{Zi}\mathrm{=}\mathrm{R}\mathrm{\cdot }{\mathrm{\omega }}^{\mathrm{2}}{\mathrm{tan\alpha \; cos\beta }}_{\mathrm{i}}$$

$${\mathrm{F}}_{\mathrm{Wed.}}\mathrm{=}{\mathrm{m}}_{\mathrm{k}}\mathrm{\cdot }{\mathrm{z}}_{\mathrm{i}}$$

$$\mathrm{M}\left({\mathrm{F}}_{\mathrm{Wed.}}\right)\mathrm{=}{\mathrm{m}}_{\mathrm{k}}\mathrm{\cdot }\mathrm{R}\mathrm{\cdot }{\mathrm{cos\beta }}_{\mathrm{i}}\mathrm{\cdot }{\mathrm{z}}_{\mathrm{i}}$$

$${\mathrm{M}}_{\mathrm{k}\mathrm{.}\mathrm{ges}}={\mathrm{m}}_{\mathrm{k}}\mathrm{\cdot }\mathrm{R}{\displaystyle \underset{i=1}{\overset{n}{\Sigma }}}{z}_{\mathrm{i}}\cdot {\mathrm{cos\beta }}_{\mathrm{i}}$$

Moment due to moment of deviation Msw

$${\mathrm{M}}_{\mathrm{sw}}\mathrm{=}{\mathrm{J}}_{\mathrm{Y\; Z}}\mathrm{\cdot }{\mathrm{\omega }}^{\mathrm{2}}$$

$${\mathrm{J}}_{\mathrm{Y\; Z}}=\left\{\frac{\mathit{msw}}{2}\left({{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}\right)-\frac{\mathit{msw}}{4}\left({{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}+\frac{H^2}{3}\right)\right\}\mathrm{cos\alpha \; sin\alpha }$$

$${\mathrm{J}}_{\mathrm{Y\; Z}}=\frac{\mathit{msw}}{24}\sin 2\alpha \left(3{{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}3{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}-{\mathrm{H}}^2\right)$$

θ

Drehwinkel der Welle (wobei die vor- und nachstehenden Betrachtungen der Einfachheit halber für θ=0 angestellt werden)

η

Anzahl der Kolben

R

Abstand der Kolbenachse zur Wellenachse

ω

Wellendrehzahl

α

Kippwinkel des Schwenkringes/Schwenkscheibe

mk

Masse eines Kolbens inklusive Gleitsteine bzw. Gleitsteinpaar

mk,ges

Masse aller Kolben inklusive Gleitsteine

msw

Masse des Schwenkringes

ra

Außenradius des Schwenkringes

ri

Innenradius des Schwenkringes

h

Höhe des Schwenkringes
Dichte des Schwenkringes

V

Volumen des Schwenkringes

βi

Winkelposition des Kolbens i

zi

Beschleunigung des Kolbens i

Fmi

Massenkraft des Kolbens i (inklusive einem Gleitsteinpaar)

M(Fmi)

Moment infolge der Massenkraft des Kolbens i

Mk,ges

Moment infolge der Massenkraft aller Kolben

Msw

Moment infolge des Aufstellmomentes des Schwenkringes/Schwenkscheibe (Deviationsmoment)

The sizes used above mean something like this:

θ

Angle of rotation of the shaft (the above and following considerations are for simplicity θ = 0)

η

Number of pistons

R

Distance of the piston axis to the shaft axis

ω

Shaft speed

α

Tilt angle of the swivel ring / swashplate

mk

Mass of a piston including sliding blocks or pair of sliding blocks

mk, ges

Mass of all pistons including sliding blocks

msw

Mass of the swivel ring

ra

Outer 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

βi

Angular position of the piston i

zi

Acceleration of the piston i

Fmi

Mass force of the piston i (including a sliding block pair)

M (Fmi)

Moment due to the mass force of the piston i

Mk, ges

Moment due to the mass force of all pistons

msw

Moment due to the installation torque of the swivel ring / swashplate (deviation moment)

bzw. $$\left[{\mathrm{\omega }}^2\frac{\mathit{msw}}{24}\sin 2\alpha \left(3{{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}3{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}-{\mathrm{h}}^2\right)\ge {\mathrm{\omega }}^{\mathrm{2}}{\mathrm{R}}^{\mathrm{2}}{\mathrm{m}}_{\mathrm{k}}\mathrm{tan\alpha }{\displaystyle \sum _{i=1}^n}{\cos }^2\mathrm{\beta i}\right]$$

It is in the context of the present invention goal that the moment due to the Aufstellmomentes the swash plate or the swivel ring, ie the moment of deviation is greater than / equal to the moment due to the inertial forces of all pistons, ie the following relationship applies: $${\mathrm{M}}_{\mathrm{sw}}\mathrm{\ge }\mathrm{mk}\mathrm{.}\mathrm{ges}$$

respectively. $$\left[{\mathrm{\omega }}^2\frac{\mathit{msw}}{24}\sin 2\alpha \left(3{{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}3{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}-{\mathrm{H}}^2\right)\ge {\mathrm{\omega }}^{\mathrm{2}}{\mathrm{R}}^{\mathrm{2}}{\mathrm{m}}_{\mathrm{k}}\mathrm{tan\alpha }{\displaystyle \underset{i=1}{\overset{n}{\Sigma }}}{\cos }^2\mathrm{\beta i}\right]$$

• Kolbenzahl: n = 7
• Abstand Kolbenachse zur Antriebswellen-Längsachse: R = 25 mm
• Innenradius r_i/Außenradius r_a des Schwenkringes: r_i / r_a = 15/35
• Dichte: δ = 7, 9
• Schwenkringhöhe: h = 10 mm
• Masse/Kolben: m_k = 39

vorausgesetzt wird: Tabelle 1 Einfluss der Drehzahl auf die Kippmomente n Mk,ges Msw alpha [1/min] [Nm] [Nm] [°] 800 0,11 0,11 10 1500 0,37 0,37 10 3000 1,48 1,48 10 5000 4,12 4,12 10 8000 10,56 10,55 10 11000 19,98 19,95 10 Tabelle 2 Einfluss des Kippwinkels auf die Kippmomente alpha Mk,ges Msw n [°] [Nm] [Nm] [1/min] 0 0,00 0,00 3000 3 0,44 0,45 3000 6 0,88 0,90 3000 10 1,48 1,48 3000 14 2,10 2,04 3000 18 2,74 2,55 3000 The above equation shows that the speed has a similar influence on both terms and therefore does not change speed changes on the torque ratio. This is also evident from the following example in Tables 1 and 2, wherein:

• Piston number: n = 7
• Distance between piston axis and drive shaft longitudinal axis: R = 25 mm
• Inner radius r _i / outer radius r _{a of} the swivel ring: r _i / r _a = 15/35
• Density: δ = 7, 9
• Swing ring height: h = 10 mm
• Mass / piston: m _k = 39

is assumed: Table 1 Influence of the speed on the tilting moments n Mk, ges msw alpha [1 / min] [Nm] [Nm] [°] 800 0.11 0.11 10 1500 0.37 0.37 10 3000 1.48 1.48 10 5000 4.12 4.12 10 8000 10.56 10.55 10 11000 19.98 19,95 10 Influence of the tilt angle on the tilting moments alpha Mk, ges msw n [°] [Nm] [Nm] [1 / min] 0 0.00 0.00 3000 3 0.44 0.45 3000 6 0.88 0.90 3000 10 1.48 1.48 3000 14 2.10 2.04 3000 18 2.74 2.55 3000

Table 2 shows that the respective swash plate or ring tilt angle changes only slightly at the torque ratio. Furthermore, it follows from the above equation that tanα ≠ sin2α, and that accordingly the torque ratio, in particular for small angles α, depends little on the angle α. This results in a meaningful design for a mean angle α: _{Mk, ges} = _Msw , or for _αmax : _{Mk, ges} = _Msw . The swash plate acts compensating.

• Schwenkscheibe wirkt kompensierend
• Schwenkscheibe wirkt abregelnd bzw. überkompensierend

Table 3 below shows results for the case:

• Swivel disk compensates
• Pivoting disc has a decreasing or overcompensating effect

Consequently, essentially only the geometric variables are relevant for the moment equilibrium, whereby, of course, the masses of the pistons and the swash plate also have an influence. Specifically, the following quantities are of relevance to the moment equilibrium: $$\left[{\mathrm{m}}_{\mathrm{k}\mathrm{.}\mathrm{ges}}\mathrm{/}\mathrm{msw}\mathrm{/}{\mathrm{R}}^{\mathrm{2}}\mathrm{/}{{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{/}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}\mathrm{/}{\mathrm{H}}^{\mathrm{2}}\right]$$

zu berechnen.When forming the swash plate as a pivot ring, it is expedient, the distance between the piston axis and drive shaft axis from the relationship $$\mathrm{R}\mathrm{=}\left({\mathrm{r}}_{\mathrm{a}}\mathrm{+}{\mathrm{r}}_{\mathrm{i}}\right)\mathrm{/}\mathrm{2}$$

to calculate.

For an optimal design of the swash plate, here the swivel ring 107 is preferably based on the quotient "moment of inertia / mass", ie "J / m". This quotient expresses the magnitude of the mass moment of inertia at a predetermined swashplate or swivel ring mass. The quotient should be greater than 250 gmm ² / g. Ratios of greater than 400-500 gmm ² / g are particularly advantageous. "J" refers to each axis of gravity (ie: J = J ₁ = J ₂ = J ₃ , with J ₃ ≈ 2J _{2 as a} rule), the center of gravity of the rotating mass preferably being in the center of the tilting joint.

Greater mass inertias are to be selected in particular if piston masses are chosen to be significantly greater than 40 g / piston.

With the construction according to the invention, in particular a mechanical reduction of the flow rate of an axial piston compressor should be achieved with an increase in speed. The ideal case would of course be a constant control, wherein the constant control is a sub-case of the inventively aimed by mechanical and torque distribution caused mechanical Abregelung.

The following example shows an advantageous design for different radii, volumes and masses for a pivot ring 107: Table 4 Inside radius r _i [mm] Outer radius r _a [mm] Height H [mm] Density ζ [g / cm ³ ] Volume V [mm ³ ] Mass m [g] Mass inertia J [g mm ² ] Quotient J / m [g mm ² / g] 15.0 35.0 10.0 7.9 31416 248 92036 371 17.5 37.5 10.0 7.9 34558 273 119155 437 20.0 40.0 10.0 7.9 37699 298 151393 508 15.0 35.0 16.0 7.9 50265 397 152419 384 17.5 37.5 16.0 7.9 55292 437 196327 449 20.0 40.0 16.0 7.9 60319 477 248424 521

$$\mathrm{V}=\frac{\mathit{\pi }}{4}\cdot h\left({\mathrm{D}}^{\mathrm{2}}\mathrm{-}{\mathrm{d}}^{\mathrm{2}}\right)$$

$$\mathrm{D}\mathrm{=}\mathrm{2}{\mathrm{r}}_{\mathrm{a}}$$

$$\mathrm{d}\mathrm{=}\mathrm{2}{\mathrm{r}}_{\mathrm{i}}$$

$$\mathrm{J}\mathrm{=}\mathrm{m}\mathrm{/}\mathrm{4}\left({{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}\mathrm{+}{\mathrm{h}}^{\mathrm{2}}\mathrm{/}\mathrm{3}\right)$$

The above values result from the following general equations for a swivel ring: $$\mathrm{m}\mathrm{=}\mathrm{\varsigma V}$$

$$\mathrm{V}=\frac{\mathit{\pi }}{4}\cdot H\left({\mathrm{D}}^{\mathrm{2}}\mathrm{-}{\mathrm{d}}^{\mathrm{2}}\right)$$

$$\mathrm{D}\mathrm{=}\mathrm{2}{\mathrm{r}}_{\mathrm{a}}$$

$$\mathrm{d}\mathrm{=}\mathrm{2}{\mathrm{r}}_{\mathrm{i}}$$

$$\mathrm{J}\mathrm{=}\mathrm{m}\mathrm{/}\mathrm{4}\left({{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}\mathrm{+}{\mathrm{H}}^{\mathrm{2}}\mathrm{/}\mathrm{3}\right)$$

As stated above, the design is preferably based on the quotient "J / m" in general, and preferably specifically on the ratio "J _y / m _{k, ges} ", ie on the quotient of mass inertia of the swashplate or swivel ring in FIG Referring to the y-axis according to Fig. 9 and the entire 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, ges} of significantly smaller than "1" is very disadvantageous the goal here rule behavior. The above ratio must therefore be avoided.

At a mass ratio of m _sw / m _{k, ges} = 1 results preferably for the ratio J _y / m _{k, ges} a minimum value for compensation of about 250 ... 300 g mm ² / g.

Larger values can be set depending on the desired control behavior; In particular, however, is an exact compensation of changes in the swashplate tilt angle at a mass ratio of m _{k, ges} = m _sw of interest.

Overcompensation may also be of interest, particularly in compensating for the change in flow rate due to speed changes.

Similarly, the quotients J _z / m _{k, ges} and J _z / m _{sw could be used} for the design for the desired control behavior, since the moment of inertia J _z with respect to the z- or drive shaft axis together with J _y the relevant Deviationmoment forms. In this case, the relationship applies for the illustrated swivel ring geometry: $${\mathrm{J}}_{\mathrm{z}}\mathrm{\approx }\mathrm{2}{\mathrm{J}}_{\mathrm{y}}\mathrm{,}$$

Since J _yz ≈ J _z (...) - J _y (...), and since J _{yz should be} large, J _{z is} actually the more important size. J _y can be used as a reference only because the above relation J _z ≈ 2 J _y holds.

All disclosed in the application documents features are claimed as essential to the invention, as far as they are new individually or in combination over the prior art.

reference numeral

100

Swivel-disk mechanism

101

Swivel bearing (swivel axis)

104

drive shaft

107

swivel

107i

inner swivel ring

107a

outer swivel ring

108

sliding sleeve

109

Support element (axial support)

110

supporting arch

112

disc

113

circumferential groove

114

counterweight

Claims (15)

1. Axial piston compressor, especially a compressor for the air-conditioning system of a motor vehicle, having a housing and, for drawing in and compressing a coolant, a compressor unit arranged in the housing and driven by means of a drive shaft (104), the compressor unit comprising pistons moving axially back and forth in a cylinder block and comprising a swash plate (107) which drives the pistons and rotates together with the drive shaft (104),
   characterised in that
   for a predetermined mass of the swash plate (107) moved in rotation on the one hand and/or a particular mass moved in translation (for example, pistons, piston rod and/or sliding blocks) on the other hand, the mean radius governed by the geometry and/or by the density distribution and/or the mean height of the swash plate (107) or of the pivotal portion thereof is/are so selected that the centrifugal forces occurring on rotation of the swash plate (107) are sufficient to counteract the pivotal movement of the swash plate (107) to provide deliberate regulation and thereby to influence, especially to reduce or to limit, the piston stroke and, consequently, the quantity delivered.
2. Axial piston compressor according to claim 1,
   characterised in that
   the swash plate is a swash ring (107).
3. Axial piston compressor according to claim 1 or 2,
   characterised in that
   the quotient moment of inertia/mass "J/m" of the swash plate (107) or of the pivotal part thereof is at least about 250 gmm²/g, especially greater than 400 to 500 gmm²/g, higher values being selected when the piston masses are greater than 40 g/piston, and the moment of inertia "J" being calculated in relation to each axis through the centre of gravity of the swash plate or of the pivotal part thereof.
4. Axial piston compressor according to claim 3,
   characterised in that
   the swash plate or the pivotal part thereof is made from a material having a density of at least 6 - 8 g/cm³.
5. Axial piston compressor according to one of claims 1 - 4,
   characterised in that
   the swash plate (107) or the pivotal part thereof is made from two or more disparate materials governing the mean radius for the calculation of the mass moment of inertia, the disparate materials being separated from one another radially and/or axially, especially so that in the case of a swash ring (167) an outer (107a) or inner partial ring is made from a first material (107i), for example a material of relatively high density, such as lead or the like, inside an outer (113) or inner circumferential groove of an inner (107i) or outer partial ring, which is made from relatively hard and wear-resistant material such as, for example, steel, ceramic material or the like.
6. Axial piston compressor according to one of claims 1 - 5,
   characterised in that
   the swash plate (107) or the pivotal part thereof has, in relation to each centre of gravity axis, a mass moment of inertia "J" greater than 100,000 g/mm², especially greater than 200,000 to 250,000 g/mm².
7. Axial piston compressor according to one of claims 1 - 6,
   characterised in that
   the pistons each have a mass of about 30 g to 90 g, especially 35 g to 50 g.
8. Axial piston compressor according to one of claims 1 - 7,
   characterised in that
   the mean radius and/or the mean height of the swash plate or of the pivotal part thereof is/are so dimensioned that the centrifugal forces occurring on rotation of the swash plate (107), which forces counteract the pivotal movement of the swash plate (107), are greater than the forces acting on the swash plate from the pistons, which forces cause further extending pivotal movement, so that with increasing speed of rotation the piston stroke is reduced by an amount such that an approximately constant delivered quantity is established.
9. Axial piston compressor according to one of claims 1 - 8,
   characterised in that
   the centre of gravity of the swash plate (107) or of the pivotal part thereof is located in or at least close to the axis of the drive shaft (104), where especially also the centre of the tilt-providing articulation is located.
10. Axial piston compressor according to one of claims 5 - 9,
    characterised in that,
    when the swash plate (107) or the pivotal part thereof is made from a plurality of materials of different densities, the radially outer parts (107a) consist of denser material than the radially inner parts (107i).
11. Axial piston compressor according to one of claims 2 - 10,
    characterised in that,
    when the swash plate is in the form of a swash ring (107), the inner and outer diameters are each selected maximally within the external conditions (for example, inner diameter of the drive mechanism space, sufficient support for the sliding blocks of an articulated arrangement effective between the pistons and swash plate, etc.).
12. Axial piston compressor according to one of claims 5 - 11,
    characterised in that,
    when the swash plate is made from at least two materials of different densities, one material has a density of 6 - 8 g/cm³, whereas the other material has a density greater than 6-8 g/cm³.
13. Axial piston compressor according to one of claims 1 - 12,
    characterised in that
    the quotient M_sw/M_k,ges is ≥ 1, M_sw being the moment due to the moment of deviation of the swash plate and M_k,ges being the moment due to the mass forces of the masses moved in translation (pistons).
14. Axial piston compressor according to one of claims 1 - 13,
    characterised in that
    the quotient of the mass inertia of the swash plate in relation to the y axis, that is to say an axis perpendicular to the z or drive shaft axis, and the total piston mass "J_y/m_k,ges" is at least about 250 - 300 g mm²/g for the case where m_sw/m_k,ges = 1, wherein:

    m_sw = mass of the swash plate (= rotating mass)

    m_k,ges = mass of all pistons, including sliding blocks (= translational mass).
15. Axial piston compressor according to one of claims 2 - 14,
    characterised in that
    the distance "R" between the piston axis and drive shaft axis results from the relation $$\mathrm{R}\mathrm{=}\left({\mathrm{r}}_{\mathrm{a}}\mathrm{+}{\mathrm{r}}_{\mathrm{i}}\right)\mathrm{/}\mathrm{2}$$

    

    
    wherein
    r_a = outer radius of the swash ring (107), and
    r_i = inner radius of the swash ring (107).

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