EP1673537B1 - Axial piston compressor, especially for the air conditioning system of a motor vehicle - Google Patents

Description

The invention relates to an axial piston compressor, in particular compressor for the air conditioning systems of a motor vehicle, with a housing and a housing arranged in the housing, driven via 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 (oblique or swivel ring or swash plate) comprises.

Such Axialkolbenverdichter is for example from the DE 197 49 727 A1 known. This comprises 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 a gaseous working fluid of the compressor is present at a certain pressure. The delivery volume and thus the capacity of the compressor are dependent on the pressure ratio between the suction side and pressure side of the piston or 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 to cause a setting up of the moment of the swashplate device in the direction of minimal stroke of the piston, whereby influence on the control behavior is taken.

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

Even with series compressors, as used in vehicles, one aims at a suitable dimensioning of the moving components (in particular mass) to the to achieve desired control behavior. The series compressor 6SEU 12 C from DENSO, for example, has an engine with the following masses that are 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 rotato risch moved 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 counter-force 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 affect 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 (zum Beispiel Schwenkscheibe: Kippposition ≠ Massenschwerpunkt): kann (+) oder (-) sein
• Moment infolge der translatorisch bewegten Massen (+)

The influencing variables which act as moments about the tilting center of a swivel disk device are in detail the following moments, wherein in each case the direction of the moments is indicated in brackets and (-) adjustable (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 (+) or (-)
• Moment due to translationally moving masses (+)

With respect to the mentioned compressor 6SEU 12 C from 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 depending on the Schwenkscheibenkippwinkel (the center of gravity moves "like a swing" below the tilting joint), and leads in the worst case to an aufzustenden property (so-called. "center of gravity").

Thus, in the prior art compressors, both prior art and actual prior art, a compromise has to be made in that a predetermined mass of the swashplate is provided to counteract the translationally moved masses. 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. Moreover, in forming a swash plate in the form of a swivel ring, the increase in the same mass is limited by the height.

To address this problem, it has already been proposed to use the pistons, i. the translationally moving masses as low as possible, i. easy to build, e.g. made of aluminum or other materials of lower specific gravity. There is also the suggestion to use hollow piston in this regard.

Furthermore, the compressor according to the EP 0 809 027 A1 directed. It is about a particular embodiment of the coupling mechanism between the drive shaft and swivel disk device. The coupling mechanism is designed for high pressure, for example, when used as a refrigerant R744. Furthermore, the last-mentioned prior art also deals with a so-called constant regulation of the flow rate. It is proposed to design the kinematics of the compressor in such a way that the decelerating tilting moments acting on the swashplate clearly dominate the overturning overturning moments. It should be noted that the term "flow rate" is relatively blurred. The delivery rate could be regarded as constant, if, for example, when doubling the speed halves the tilt angle of the swash plate. This would geometrically the flow rate constant. Of course, other parameters affect the flow rate when the tilt angle of the swash plate changes, eg. Degree of delivery, oil throw od. Like ..

For a constant control of the flow rate at varying rotational speeds, the restoring torque of the swash plate is utilized because the swash plate counteracts their inclination due to the dynamic forces on the co-rotating disc part. This behavior can be supported by the force of a spring, so that the increasing with increasing rotational speed or speed flow rate is at least partially compensated by resetting the oblique or pivotal position of the swash plate.

As already explained above, in principle such a behavior can be achieved by, for example, integrating an additional mass into the engine, the mass inertia of which acts on the swashplate via a coupling mechanism. Furthermore, it has been stated that the mass of the swash plate can not be selected arbitrarily large in compressors, such as are currently used in motor vehicles, without having to put up with other disadvantages. This applies in particular to the teaching according to the DE 198 39 914 A1 or the EPA-115 1197 , The proposed there regulation with the mass of the rotating components can lead to a control behavior by which the flow rate should be largely independent of speed. However, this is not inevitable. It can also lead to overcompensation. The design criteria are very blurred. The reason for this is that the mass of the rotating components only proportionally influences the installation torque of the swashplate, but the speed (ω) is quadratic. This means that the flow rate can only be compensated in the higher speed range (dynamics play a role here) and for exactly 2 speeds.

Furthermore, compressors are known, in particular series compressors for R134a, in which the stroke volume increases on the sole side due to the acting moments of up-regulating and regulating mass forces. By appropriate control intervention of the control valves used that may need to be compensated. Recent developments, especially for CO ₂ compressors, seek to reverse this behavior. The necessary control intervention can then be reduced or even dispensed with.

• Hochdruck 120 bar und Saugdruck 35 bar.
• Gerechnet wurde weiterhin mit Drehzahlen:
• 600 U/min, 1200 U/min, 2500 U/min, 5000 U/min, 8000 U/min und 11000 U/min.

For better understanding, the tilting behavior described as a result of a speed fluctuation in the FIGS. 2 and 3 shown. Fig. 2 shows the dependence of the engine room pressure difference relative to the suction pressure on the tilt angle α or "alpha" of the swash plate. By way of example, the following pressures were assumed for the calculation:

• High pressure 120 bar and suction pressure 35 bar.
• Calculated was still at speeds:
• 600 rpm, 1200 rpm, 2500 rpm, 5000 rpm, 8000 rpm and 11000 rpm.

To recognize are in Fig. 2 but only five of the six calculated courses. This is because the gradients for the speeds of 600 rpm and 1200 rpm are substantially completely superimposed (due to lack of dynamics); therefore is the promoted in the art "speed independent flow rate" rather a wishful imagination, which is not met with the measures outlined.

Based on the diagram according to Fig. 2 can be easily seen that arise gradients that cause an adjustment of the swashplate to larger tilt angles, as the speed increases. The calculation was based on a pivot ring with a predetermined inner and outer diameter and a predetermined height.

In addition, the piston mass is relevant, the pitch diameter on which the pistons are located, and the number of pistons.

The swivel ring 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.Next, the pivot ring preferably has a moment of inertia of ${\mathrm{<figure-callout\; id="3"\; label="J"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">J</figure-callout>}}_{\mathrm{3}}\mathrm{=}{\mathrm{J}}_{\mathrm{\zeta }}\mathrm{=}\frac{m}{\mathrm{2}}$

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

$$\begin{array}{c}\begin{array}{l}\begin{array}{l}{\mathrm{\alpha }}_2\mathrm{=}\mathrm{90}°\\ {\mathrm{\beta }}_2\mathrm{=}\mathrm{\psi }\\ {\mathrm{\gamma }}_2\mathrm{=}\mathrm{90}\mathrm{°}+\mathrm{\psi }\end{array}\end{array}\mathrm{\}}\mathrm{Richtungswinkel\; der\; y}\mathrm{-}\mathrm{Achse\; gegenüber\; der\; Hauptträgheitsachsen\; \xi }\mathrm{\cdot }\mathrm{\eta }\mathrm{\cdot }\mathrm{\zeta }\end{array}$$

$$\begin{array}{c}\begin{array}{l}\begin{array}{l}{\mathrm{\alpha }}_3\mathrm{=}\mathrm{90}°\\ {\mathrm{\beta }}_3\mathrm{=}\mathrm{90}\mathrm{°}\mathrm{-}\mathrm{\psi }\\ {\mathrm{\gamma }}_3\mathrm{=}\mathrm{\psi }\end{array}\end{array}\mathrm{\}}\mathrm{Richtungswinkel\; der\; z}\mathrm{-}\mathrm{Achse\; gegenüber\; den\; Hauptträgheitsachsen\; \xi }\mathrm{\cdot }\mathrm{\eta }\mathrm{\cdot }\mathrm{\zeta }\end{array}$$

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

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

Below is the derivation of the so-called. Deviation torque is given, 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 swivel 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. 13 : $$\begin{array}{l}{\mathrm{J}}_{\mathrm{Y\; Z}}\mathrm{=}\mathrm{-}{\mathrm{<figure-callout\; id="1"\; label="J"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">J</figure-callout>}}_{\mathrm{1}}\cos {\mathrm{\alpha }}_{\mathrm{2}}\cos {\mathrm{\alpha }}_{\mathrm{3}}\mathrm{-}{\mathrm{<figure-callout\; id="2"\; label="J"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">J</figure-callout>}}_{\mathrm{2}}\cos {\mathrm{\beta }}_{\mathrm{2}}\cos {\mathrm{\beta }}_{\mathrm{3}}\mathrm{-}{\mathrm{<figure-callout\; id="3"\; label="J"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">J</figure-callout>}}_{\mathrm{3}}\cos {\mathrm{\gamma }}_{\mathrm{2}}\cos {\mathrm{\gamma }}_{\mathrm{3}}\\ \begin{array}{l}\begin{array}{l}{\mathrm{<figure-callout\; id="1"\; label="\alpha "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\alpha </figure-callout>}}_{\mathrm{1}}\mathrm{=}\mathrm{0}\\ {\mathrm{<figure-callout\; id="1"\; label="\beta "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\beta </figure-callout>}}_{\mathrm{1}}\mathrm{=}\mathrm{90}\mathrm{°}\\ {\mathrm{<figure-callout\; id="1"\; label="\gamma "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\gamma </figure-callout>}}_{\mathrm{1}}\mathrm{=}\mathrm{90}\mathrm{°}\end{array}\end{array}\mathrm{\}}\mathrm{Direction\; angle\; of\; the\; x}\mathrm{-}\mathrm{Axis\; opposite\; to\; the\; main\; axes\; of\; inertia\; \xi }\mathrm{\cdot }\mathrm{\eta }\mathrm{\cdot }\mathrm{\zeta }\end{array}$$

$$\begin{array}{c}\begin{array}{l}\begin{array}{l}{\mathrm{\alpha }}_2\mathrm{=}\mathrm{90}°\\ {\mathrm{<figure-callout\; id="2"\; label="\beta "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\beta </figure-callout>}}_2\mathrm{=}\mathrm{\psi }\\ {\mathrm{\gamma }}_2\mathrm{=}\mathrm{90}\mathrm{°}+\mathrm{\psi }\end{array}\end{array}\mathrm{\}}\mathrm{Directional\; angle\; of\; the\; y}\mathrm{-}\mathrm{Axis\; opposite\; to\; the\; main\; axes\; of\; inertia\; \xi }\mathrm{\cdot }\mathrm{\eta }\mathrm{\cdot }\mathrm{\zeta }\end{array}$$

$$\begin{array}{c}\begin{array}{l}\begin{array}{l}{\mathrm{\alpha }}_3\mathrm{=}\mathrm{90}°\\ {\mathrm{<figure-callout\; id="3"\; label="\beta "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\beta </figure-callout>}}_3\mathrm{=}\mathrm{90}\mathrm{°}\mathrm{-}\mathrm{<figure-callout\; id="3"\; label="\psi \; \gamma "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\psi \; </figure-callout>}& \\ {\mathrm{\gamma }}_{}{\mathrm{}}_3\mathrm{=}\mathrm{\psi }\end{array}\end{array}\mathrm{\}}\mathrm{Direction\; angle\; of\; z}\mathrm{-}\mathrm{Axis\; opposite\; to\; the\; main\; axes\; of\; inertia\; \xi }\mathrm{\cdot }\mathrm{\eta }\mathrm{\cdot }\mathrm{<figure-callout\; id="2"\; label="\zeta \; J"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\zeta \; </figure-callout>}& \\ \end{array}$$

$${\mathrm{J}}_{}$$$${\mathrm{}}_{\mathrm{2}}\mathrm{=}{\mathrm{J}}_{\mathrm{\eta }}\mathrm{=}\frac{\mathrm{<figure-callout\; id="4"\; label="m"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">m</figure-callout>}}{4}\left({{\mathrm{r}}_{\mathrm{a}}}^2\mathrm{+}{{\mathrm{<figure-callout\; id="2"\; label="r\; i"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">r\; </figure-callout>}}_{\mathrm{i}}}^{\mathrm{2}}+\frac{{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">H</figure-callout>}}^2}{3}\right)$$

$${\mathrm{<figure-callout\; id="3"\; label="J"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">J</figure-callout>}}_3\mathrm{=}{\mathrm{J}}_{\mathrm{\zeta }}\mathrm{=}\frac{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">m</figure-callout>}}{2}\left({{\mathrm{r}}_{\mathrm{a}}}^2\mathrm{+}{{\mathrm{<figure-callout\; id="2"\; label="r\; i"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">r\; </figure-callout>}}_{\mathrm{i}}}^{\mathrm{2}}\right)$$

( Note: J ₃ ≈ 2 J ₂

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

of inertia

Independent of Figure 13 applies:

Moment due to inertia of the pistons

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

$$\mathrm{Zi}\mathrm{=}\mathrm{R}\mathrm{\cdot }{\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\omega </figure-callout>}}^{\mathrm{2}}\mathrm{tan\alpha \; cos}{\mathrm{\beta }}_{\mathrm{i}}$$

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

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

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

Moment Msw due to moment of deviation

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

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

$${\mathrm{M}}_{\mathrm{SW}}\mathrm{\ge }{\mathrm{M}}_{\mathrm{k}\mathrm{,}\mathrm{ges}}$$

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

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

$${\mathrm{J}}_{\mathrm{Y\; Z}}=\left\{\frac{\mathit{<figure-callout\; id="2"\; label="msw"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">msw</figure-callout>}}{2}\left({{\mathrm{r}}_{\mathrm{a}}}^2\mathrm{+}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}\right)-\frac{\mathit{<figure-callout\; id="4"\; label="msw"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">msw</figure-callout>}}{4}\left({{\mathrm{r}}_{\mathrm{a}}}^2\mathrm{+}{{\mathrm{<figure-callout\; id="2"\; label="r\; i"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">r\; </figure-callout>}}_{\mathrm{i}}}^{\mathrm{2}}+\frac{{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">H</figure-callout>}}^2}{3}\right)\right\}\mathrm{cos\alpha \; sin\alpha }$$

$${\mathrm{J}}_{\mathrm{Y\; Z}}=\frac{\mathit{<figure-callout\; id="24"\; label="msw"\; filenames="imgf0004.png"\; state="\{\{state\}\}">msw</figure-callout>}}{24}\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">sin</figure-callout>}\mathrm{2}\mathrm{\alpha }\left(\mathrm{3}{{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}\mathrm{3}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}-{\mathrm{H}}^{\mathrm{2}}\right)$$

$${\mathrm{M}}_{\mathrm{SW}}\mathrm{\ge }{\mathrm{M}}_{\mathrm{k}\mathrm{.}\mathrm{ges}}$$

respectively. $$\left[{\mathrm{\omega }}^{\mathrm{2}}{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">R</figure-callout>}}^{\mathrm{2}}\mathrm{\cdot }{\mathrm{m}}_{\mathrm{k}}\mathrm{tan\alpha }{\displaystyle \underset{n\mathrm{=}\mathrm{1}}{\overset{\mathrm{<figure-callout\; id="2"\; label="n\; cos"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">n\; </figure-callout>}}{\mathrm{\Sigma }}}}{\cos }^{}{}^{\mathrm{2}}\mathrm{\beta }\mathrm{=}{\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\omega </figure-callout>}}^{\mathrm{2}}\frac{\mathit{msw}}{\mathrm{24}}\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">sin</figure-callout>}\mathrm{2}\mathrm{<figure-callout\; id="3"\; label="\alpha "\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">\alpha </figure-callout>}\left(\mathrm{3}{{\mathrm{r}}_{\mathrm{a}}}^{\mathrm{2}}\mathrm{+}\mathrm{3}{{\mathrm{r}}_{\mathrm{i}}}^{\mathrm{2}}\mathrm{-}{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">H</figure-callout>}}^{\mathrm{2}}\right)\right]$$

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

ρ

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 infolge des Deviationsmoments (J_yz)

J =

f (ρ , r, h) Massenträgheitsmoment

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

ρ

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 as a result of the deviation moment (J _yz )

J =

f (ρ, r, h) mass moment of inertia

Specifically, the lay Fig. 2 following tilting moment determination of the swivel or swash plate, wherein α was varied from 0 ° to 16 °:

It can be seen that the influence of the piston mass predominates and thus results in the aufrichtende behavior of the inclined or swash plate with increasing speed.

It is thus the case M _{k, ges} > M _sw

In Fig. 3 is a diagram for a nearly identical engine specified, this diagram is based on the following calculation scheme, where also α was varied from 0 ° to 16 °:

Here is the case M _{k, ges} <M _sw .

This calculation scheme shows that compared to the calculation too Fig. 2 the thickness or height of the inclined or swashplate of 10 mm ( Fig. 2 ) to 18. mm ( Fig. 3 ) has been increased. This has the consequence that the relevant moment of inertia J _z increases to approximately twice the value. In Fig. 3 is a derating behavior of the swashplate engine to recognize. This trend is indicated by the arrow "n" in Fig. 3 , where "n" means the speed of the swash plate or drive shaft. The same meaning of course has the arrow "n" in Fig. 2 , only there is the arrow reversed, causing a Aufregeln to be displayed with increasing speed.

The FIGS. 2 and 3 reflect the state of the art. Here, the aufrichtende behavior is appropriate Fig. 2 Frequently detectable in current R134a series compressors. In more recent developments, one tries rather to convert this trend into the opposite, namely accordingly Fig. 3 ,

Starting from the cited prior art, it is an object of the present invention to provide an axial piston compressor of the type mentioned on the swash plate device speed fluctuations have a minimal influence, i. not the flow rate, but the tilt angle of the swash plate should be influenced as little as possible by the speed.

This object is achieved by the characterizing features of claim 1, wherein advantageous developments and details of the invention are described in the dependent claims. The axial piston compressor can be used in particular as a compressor in the air conditioning system of a motor vehicle. By translationally moving parts are understood, for example, axial piston, piston rod or sliding blocks, and under rotationally moving parts, for example, a swash plate, driver or the like. The moment M _{k, ges} should be due to the translationally moving masses, in particular the piston, if necessary, including sliding blocks, piston rods od. Like., Be approximately equal to the moment M _SW due to the Deviationsmoments.

The core of the present invention is therefore to match the geometry and dimensioning of the translationally moving parts on the one hand and rotationally moving parts on the other hand so that the consequent moments are always about the same size, so that the swashplate tilt angle at varying speeds substantially remains constant.

• günstiges dynamisches Verhalten: vermindertes Aufschwingen und Gegenregeln durch Ventile;
• Verminderung der Streuung der Kennlinien; dadurch kann bei der Auslegung jeder Betriebspunkt optimal berücksichtigt bzw. im Kennfeld platziert werden (besonders interessant bei CO₂-Verdichtern, da bei diesen im Vergleich zu R134a-Verdichtern neben den AC(Air Conditioning)-Betriebspunkten auch die HP(Heat-Pump)-Betriebspunkte berücksichtigt werden müssen);
• durch Überlagern eines Momentes infolge Schwerpunktlage kann man in etwa die eingestellten Verläufe der Kennlinien erhalten, diese aber gezielt verschieben.

This gives you the following advantages:

• favorable dynamic behavior: reduced swinging and counter-regulation by valves;
• Reduction of the dispersion of the characteristic curves; This means that every operating point can be optimally taken into account or placed in the characteristic map (especially interesting for CO ₂ compressors, since in comparison to R134a compressors, the HP (heat pump), in addition to the AC (air conditioning) operating points) Operating points must be taken into account);
• By superimposing a moment as a result of the center of gravity, it is possible to obtain roughly the set curves of the characteristic curves, but to shift them in a targeted manner.

According to the invention, it is therefore necessary to set the sum of the translational and rotational moments to "zero". From the above-mentioned equations for M _sw due to (moment of deviation) and M _{k, ges, it} follows that if these two moments are equalized, the speed factor "ω ² " is shortened.

Furthermore, the inventors have recognized that, however, an influence of the tilt angle of the swash plate can not be avoided. This results from the courses of tan (alpha) and sin (2alpha). The courses of these angular functions are in Fig. 1 shown. It can be deduced from this that the influence is very small with a small tilt angle, but then increases considerably with larger tilt angles. As a rule, the swash plate tilt angles are limited by a minimum value α _min and a maximum value α _max . Conceivable are limits of 0 ° on the one hand and 30 ° on the other. In practice, the minimum and maximum values are between about 0.6 ° and 18 °. Building on this is off Fig. 1 recognizable that one has to reckon with a deviation of 13% in the latter area. That is, if a balance between aufzustdenendes and abzustdenden masses would be realized for a minimum tilt angle, so must at the opposite limit of the swash plate still expect an undesirable tilting behavior (speed count due to the tilt angle).

With the present invention, the engine should be designed so that at least approximately the aforementioned undesirable behavior with respect to the speed change at different tilt angles is greatly reduced.

The Fig. 4 shows the tilting characteristic of the swashplate for an engine, for which at a tilt angle of 1 °, the mass forces / moments are constructively adjusted so that aufzustende and abregder tipping moments approximately compensate. The corresponding calculation scheme is as follows:

In the Fig. 4 Tilt characteristic shown refers to a pressure of 120 bar on the high pressure side and 35 bar on the suction side at speeds of: 600 rev / min, 1200 rev / min, 2500 rev / min, 5000 rev / min, 8000 rev / min and 11000 / min. In the above calculation scheme, the torque balance for a minimum tilt angle of 1 ° is calculated and adjusted by appropriate selection of the swashplate geometry. For all other calculations, the inner and outer diameter of the swivel disk were left unchanged, only the height of the swash plate is varied for adaptation. In the area of the pistons the mass is set constant with 45 g for all further calculations. First, to simplify the balance of the moments of Schwerikscheiben focus is directly in the tilting joint of the swash plate. The position of the pistons is approximately determined by the swash plate geometry over the relationship (r _a + r _i ) / 2. The numbers and data used are to be considered as an example only; qualitatively, however, the relationships are also representative of other assumptions. The example dealt with here refers to a compressor for CO ₂ application.

This in Fig. 4 The diagram shown shows a less satisfactory result in the control behavior at larger tilt angles. The compressor controls solely due to the tilting moments due to the translationally moving pistons on strong. Due to the above objective, this result is not exactly optimal. The compensation the tilting moments at a minimum tilt angle of α = 1 ° is demonstrated by the fact that at this tilt angle M _{k, ges is} almost equal to M _sw .

The in Fig. 5 The diagram below is based on the following calculation and results:

Fig. 5 also leaves a similar behavior as Fig. 4 detect; however, the effect of regulation was slightly reduced. The calculation was based on the calculation Fig. 4 changed the following:

As a tilt angle for setting the balance of the relevant moments to zero, a mean tilt angle of α = 8 ° has been selected.

In order to adjust the moment of inertia of the swash plate accordingly, the height of the swash plate was slightly increased, from 13.130 mm to 13.404 km.

The torque balance in the calculation scheme has a compensation of the moments at the tilt angle of 8 °. It can also be seen that the individual characteristics in the range of lower speeds are very close to each other and even have a slightly decreasing effect. The lines then have an intersection point approximately at a tilt angle α = 8 ° and are then separated again in an upright manner.

Fig. 6

das Regelverhalten einer Schwenkscheibe, die erfindungsgemäß ausgelegt ist;

Fig. 7

das Regelverhalten einer Schwenkscheibe, die ebenfalls erfindungsgemäß, jedoch gegenüber Fig. 6 anders ausgelegt ist;

Fig. 8

das Regelverhalten einer Schwenkscheibe gemäß Erfindung für eine einzige Drehzahl von n = 5000 U/min unter Variation des Betriebspunktes (unterschiedlich eingestellter Hochdruck und Saugdruck);

Fig. 9

eine bevorzugte Ausführungsform eines Schwenkring-Triebwerkes für einen Axialkolbenverdichter in perspektivischer Ansicht;

Fig. 10

das Schwenkring-Triebwerk gemäß Fig. 9 im Axialschnitt Längslinie II-II in Fig. 9;

Fig. 11

das Triebwerk gemäß Fig. 9 in Explosionsdarstellung;

Fig. 12

die Einteilung des Triebwerkes gemäß Fig. 9 in vier Quadranten Q1, Q2, Q3 und Q4;

Fig. 13

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

Fig. 14a - 21

den Einfluß der Lage des Schwerpunktes der Schwenkscheibe relativ zur Kippachse, wobei die Kippachse den Nullpunkte für die Koordinaten y und z definieren.

Reference to the other figures, the invention and the object of the present invention will now be described in more detail. In detail, the figures show what follows:

Fig. 6

the control behavior of a swash plate, which is designed according to the invention;

Fig. 7

the control behavior of a swash plate, which also according to the invention, but opposite Fig. 6 is designed differently;

Fig. 8

the control behavior of a swash plate according to the invention for a single speed of n = 5000 rev / min with variation of the operating point (differently set high pressure and suction pressure);

Fig. 9

a preferred embodiment of a swivel ring engine for an axial piston in perspective view;

Fig. 10

the swivel ring engine according to Fig. 9 in axial section longitudinal line II-II in Fig. 9 ;

Fig. 11

the engine according to Fig. 9 in exploded view;

Fig. 12

the classification of the engine according to Fig. 9 in four quadrants Q1, Q2, Q3 and Q4;

Fig. 13

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

Fig. 14a - 21

the influence of the position of the center of gravity of the swash plate relative to the tilt axis, wherein the tilt axis define the zero points for the coordinates y and z.

zeigt das Regelverhalten eines Schwenkring-Triebwerkes, welches derart dimensioniert ist, dass bei einem Kippwinkel von 16° ein Momentenausgleich stattfindet, wobei der Kippwinkel von 16° gleich α_max sein soll. Die Höhe der Schwenkscheibe wurde auf 14,292 mm angepasst. Es sei an dieser Stelle darauf hingewiesen, dass natürlich auch andere Schwenkscheibenparameter für die Einstellung des Massenträgheitsmomentes herangezogen werden können. Um eine einfache Vergleichbarkeit herzustellen, wurde aber lediglich beispielhaft der Parameter "Schrägscheibenhöhe" ausgewählt. Fig. 6 and the following calculation scheme

shows the control behavior of a swivel ring engine, which is dimensioned such that at a tilt angle of 16 ° takes place a moment compensation, the tilt angle of 16 ° should be equal to α _max . The height of the swivel disc has been adjusted to 14.292 mm. It should be noted at this point that, of course, other swash plate parameters can be used for the adjustment of the mass moment of inertia. For ease of comparison, however, the parameter "swash plate height" has been selected by way of example only.

The control behavior of the swash plate according to Fig. 6 shows a particularly desired result. In the entire working range of the swash plate, ie from α _min to α _max, there is no significant aufzustenden effect of moments of moving masses; A wide dispersion of the characteristic curves is avoided by virtue of the fact that there is an intersection or convergence of the characteristic curves at maximum tilt angle, ie α _max .

The sum of the momentum of the up-regulating and regulating mass forces is approximately zero in the range between the mean and maximum tilt angle, in particular at the maximum tilt angle.

It should also be noted that the present description is based only on the result of the swash plate and the piston and possibly additional Components acting inertial forces, inertial forces and the resulting moments relate, which influence a tilting of the swash plate. In this case, an engine is used in the present case, which has only a few components. On the basis of the example on which the swivel disk, sliding blocks and pistons are based, more complex designs are of course conceivable, such as a swash plate compressor. Basically, what is said here, however, also applies to these more complex assemblies.

In addition, the instantaneous equilibrium mentioned here can be checked without the compressor having to be put into operation for this purpose. Based on the above-mentioned basic equation for torque compensation, it is obvious that the characteristic curves can be calculated from the measured geometry and the measured component masses. Possibly. must also be determined the focus of the swash plate.

The FIGS. 7 and 8 show a variant of the embodiment according to Fig. 6 , Above all, the show FIGS. 7 and 8 in that a torque compensation is also possible for a virtual tilt angle, for example a tilt angle whose magnitude is above α _max . If, for example, the working range of the swivel disk tilt angle extends from 1 ° to 16 °, the design of the engine can be carried out in such a way that the torque sum is zero at a virtual tilt angle of 22 °. Fig. 7 indicates that even in such a case, a control behavior is obtained, which comes very close to the desired goal. In Fig. 7 all characteristics coincide at the virtual tilt angle α = 22 °, namely curves for different speeds.

In Fig. 8 are the characteristics for a single speed n = 5000 rev / min, but shown different operating points, which are characterized by different ratios of high pressure and suction pressure, the high pressure between 65 bar and 120 bar, and the suction pressure between 25 bar and 50 bar , Fig. 8 indicates that, depending on the operating point, the characteristic curve is more likely to be at higher pressures in the characteristic diagram or at a somewhat lower one. In all diagrams, the characteristic curves are calculated with a spring constant with respect to the return spring (return in the direction of the minimum stroke) of 60 N / mm. Would the spring constant chosen smaller be, the characteristics would be less sloping towards greater angles of tilt. If the spring constant were to be chosen to be larger, the characteristic curves would be more declining in the direction of larger tilt angles.

Each 5000 RPM curve is representative of a set of curves at a particular operating point. If it is considered that a certain control pressure of at least 2-3 bar above the suction pressure is required, a favorable control behavior is achieved in that the characteristics have a certain, if possible in a wide range linear slope. This makes it plausible that a closely spaced "characteristic curve" is more in the desired range of the map for all operating ranges than control curves, which drift apart more strongly, as in the FIGS. 2 and 3 is shown.

In such negative cases, such as in an uplifting behavior according to Fig. 2 , is clear that parts of control curves are very easy in areas below the suction pressure (which of course is not desirable, in this case, the compressor can not be set to maximum stroke). To avoid this, then softer return springs would have to be used. In particular, at high speeds, it may then happen that over the falling characteristic at low speeds an increasing characteristic is the case. Experience shows that in such cases, very unwanted rule effects. In particular, individual pressures is no longer assigned a defined tilt angle (occurrence of relative maxima and minima or no or too little slope or inflection points).

In the Fig. 9 to 12 is a preferred embodiment of an advantageous Schwenkscheiben- or swivel ring mechanism shown. This mechanism or the corresponding swivel ring engine is designated by the reference numeral 100. It comprises an adjustable in their inclination to a drive shaft 104, rotationally driven by the drive shaft, in this case annular swash plate or swivel ring 107, said swivel ring 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 rotationally arranged support member 109. This articulated connection is as Axialabstützung trained, in particular the Fig. 10 and 11 reveal. The interaction of the pivot ring 107 with the axial piston corresponds to that of the prior art according to the DE 197 49 727 A1 ,

The pivot bearing of the pivot ring 107 defines a transverse to the drive shaft 104 extending pivot axis 101. This pivot axis is further defined by two coaxially mounted on both sides of the sliding sleeve 108 bearing pin 102, 103 (see Fig. 11 ). These bearing pins 102, 103 are mounted in radial bores of the pivot ring 107. These radial holes are in Fig. 11 designated by the reference numeral 130. The sliding sleeve 108 can for this purpose on both sides additionally bearing sleeves 105, 106 (see Fig. 11 ), which bridge the annulus 119 between the sliding sleeve 108 and the pivot ring 107.

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 effected by a pivotally connected to the pivot ring 107 support arc 110. This support arc 110 is formed so that it overlaps an effective between piston and swivel joint assembly, in such a way that regardless of the inclination of the pivot ring 107, a collision between this and the support arc 110 on the one hand and a joint assembly comprising a piston foot 111 on the other hand is excluded (see Fig. 10 ). The piston associated with the piston 111 is identified by the reference numeral 118. The support member 109 is part of a rotatably connected to the drive shaft 104 disc 112th

The support surface of the arc 110 extends approximately concentric with the center of the effective between the piston 118 and pivot ring 107 hinge assembly. 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 ring, is not affected by axial support measures. This applies in particular to the dimensioning of the aforementioned joint arrangement. The joint arrangement, as in the prior art by two spherical segment-like hinge blocks 121, 122 (see Fig. 10 ) defined, between which the pivot ring 107 slidably engages. The spherical bearing surfaces of the hinge blocks 121, 122 are corresponding spherical troughs assigned to the mutually facing end faces of the piston foot 111.

Furthermore, it can be seen that serve in the illustrated embodiment, the pivot bearing of the pivot ring 107 only for torque transmission and the support member 109 only for the axial support of the piston 118 and gas force support. The torque transmission is thus decoupled from the axial support of the pivot ring 107.

Of particular interest is still the support surface on the support member 109 for the support sheet 110. This support surface is formed as a circular arc-shaped or cylindrical bearing surface 123. In order to avoid a displacement of the support line when changing the inclination of the pivot ring 107, i. a displacement out of the center of the piston 118, the support sheet 110 is slidably mounted in the radial direction relative to the pivot ring 107.

Moreover, with respect to the construction of this engine to the date of the applicant German patent application DE-A-103 35 159 directed.

According to Fig. 12 the engine described in four areas or quadrants Q1, Q2, Q3 and Q4 with respect. Drive shaft 104 and pivot ring 107 is divided. The first quadrant Q1 is bounded by the drive shaft 104 and the piston support front side, ie the piston facing side of the pivot ring 107. The remaining quadrants join the quadrant Q1 counterclockwise about the pivot axis of the pivot ring 107.

• Q1 (positive Koordinaten z und y): abregelnd
• Q3 (negative Koordinaten z und y): abregelnd
• Q2 (positive Koordinaten z und negatives y): aufregelnd
• Q4 (negative Koordinaten z und positives y): aufregelnd

In the previous examples, it has been assumed that the center of gravity of the pivot ring 107 substantially coincides with the tilt axis which extends perpendicular to the drive shaft center axis. Based on this, however, compressors according to the prior art often have centers of gravity in the region of the swashplate, in which the center of gravity of the swashplate does not coincide with the tilting axis. According to the invention, it is conceivable to deliberately schedule a so-called "offset". Here, focal points in the quadrant Q have the following effect:

• Q1 (positive coordinates z and y): offsetting
• Q3 (negative coordinates z and y): offsetting
• Q2 (positive coordinates z and negative y): up-regulating
• Q4 (negative coordinates z and positive y): pending

The coordinate z extends parallel to the drive shaft center axis or preferably extends in this. The coordinate y extends perpendicular thereto.

If no additional mass balance is provided, the center of gravity in the prior art embodiments is very often in the fourth quadrant Q4.

It is of course possible that a center of gravity arranged in any quadrant changes the shaft side with respect to the shaft center axis when the swashplate is tilted, with the result that e.g. transforms an uplifting behavior into a regulatory behavior. However, it has also been recognized that in the area of the shaft axis, of course, the centrifugal force and possibly resulting tilting moment is rather limited.

Overall, based on the already mentioned two moments M _{k, ges} and M _sw , which can be compensated for certain tilt angle, another tilting moment due to the centrifugal force is effective, which enters as a proportion in M _sw or msw, which in the moment of deviation J _yz which in turn goes into M _sw (M _SW = J _yz · ω ² ).

Hereinafter, special embodiments are described in more detail with respect to the position of the center of gravity of the swash plate:

An "offset" is provided, which acts as an adjuster. That is, the center of gravity of the swash plate is either in the second or in the fourth quadrant, ie in Q2 or Q4.

In the Fig. 14a to 19 different cases are shown.

Fig. 14a shows the control behavior for a center of gravity that coincides with the tilt axis. In Fig. 15a the center of gravity is displaced, either in the second or in the fourth quadrant with the coordinates y = 3 / z = -2 and y = -3 / z = 2, respectively. This shift in emphasis results in the formation of an additional (partial) moment, which has an upward effect. At the selected center of gravity in the tilt angle range of, for example, 1 ° to 16 °, the variation of the torque is not so great that it can be said that the higher the speed, the more the characteristic curves can be shifted to higher pressures. In principle, it is possible thereby to push the curves a little further in a narrow band. According to Fig. 1 However, for large tilt angles, there is approximately a balanced torque balance and thus little variability (about 10-16% swashplate tilt angle). In the range of smaller and medium tilt angle, but especially at small tilt angles results in a aufregelndes moment. The aufsetzende overturning moment in the low speed range can be attractive, since one endeavors to adjust the tilt angle in connection with, for example, clutchless operation in the operating condition air conditioning "off" the lowest possible power consumption. However, there are limits to minimizing the tilt angle since the compressor must always be able to build up a small pressure difference to control a larger stroke. If the tilt angle and thus the stroke is set too small, the compressor has problems to correct. In this case, the dynamics can help to set the compressor to a larger stroke. In Fig. 14b and 15b is shown comparatively the influence of the center of gravity. As an advantage it is seen that the characteristics can be shifted approximately parallel by the feature to higher pressures. It is desirable that the compressor decelerates in the higher speed range and up-regulates in the lower speed range. This is in Fig. 15a represented by the opposite arrows "n". The Fig. 14b and 15b correspond to the Fig. 14a and 15a , in each case in the range of small tilt angles and on an enlarged scale:

Due to the real gas process and the dead spaces, which can not be avoided and which are very relevant in the compression, it comes in the range of low tilt angle that results in a kind of maximum or plateau, which no clear assignment of pressure to speed allowed and often leads to control problems.

By the present invention, this influence can be reduced, i. the gradient of the characteristic curves tends to increase slightly.

In Fig. 15b the speeds are staggered from bottom to top as follows: 600rpm, 1200rpm, 2500rpm, 5000rpm, 8000rpm and 11000rpm, with the curves for 600rpm and 1200rpm almost coincide. If the speed is increased to approx. 2500 rpm with a minimum tilt angle of 600 rpm or 1200 rpm, the tilt angle increases to 2.5 °.

In the current constructions, as already mentioned, attempts are made to minimize the minimum tilt angle. Thus, e.g. the minimum tilt angle is only about 0.6 °. However, such an area can be very critical for proper startup of the compressor. An increase in the minimum tilt angle due to a speed increase already by a few 1/10 ° can therefore be very useful.

The Fig. 16 to 19 show further examples of different center of gravity positions. This leads to the following findings:

Depending on the tilt angle, the engine provides an up or down regulation behavior.

In areas, the characteristics are very close to each other or even congruent.

The curves always intersect at one point.

Based on FIGS. 20 and 21 By way of example, the case is also shown that an additionally set-up by means of a corresponding center of gravity position has a regular effect. The focus is either in the first or third quadrant. With increasing speed, the characteristics are due to such a center of gravity position shifted to smaller pressures. Such a dimensioning of the components may be attractive, in order to regulate with increasing compressor speed solely by the sum of the effective moments.

At first glance, the illustrated control characteristic has nothing to do with a compensation of inertial forces, since at no speed the tilt angle is kept constant. As a result, the compensation of the mass forces initially only relates to the compensation of the moments M _{k, ges} and M _sw in a predetermined tilt angle. In this criterion also falls the illustrated case "adjusting moment due to the center of gravity".

Based on this, the invention relates to a compensation of the moments M _{k, ges} and M _sw and an additional moment due to the center of gravity (Aufregelnd).

The advantage of the illustrated embodiments in comparison to the prior art according to eg Fig. 3 summarized again lies essentially in the fact that there is a tilt angle for which there is a moment compensation.

Thus, the speed of the engine has only a moderate, if any, influence on the individual rotational speeds associated characteristics, if the angular functions tan (α) and sin (2α) have a significant effect. This is in any case small for small "α"

Due to the center of gravity, a different behavior can also be set. Overall, however, the speed is significantly reduced.

Due to the close bundling of the characteristic curves associated with the rotational speeds at many operating points, a desired dimensioning, e.g. the return spring easier.

The Fig. 13 should serve for a better understanding of the formulas quoted above for the calculation of the tilting moments in question here. In this respect, reference is made to the corresponding formulas and the above explanation of the individual quantities.

With reference to the characteristic curves or control curves shown above, it should also be pointed out that for the characteristics of the compressor according to the invention it is of very significant importance and also recognition that the characteristic curves or control curves for different rotational speeds are approximately parallel to one another. With such a characteristic curve the conditions according to the invention are fulfilled.

Furthermore, it should be noted that the tilt angle of the swash plate or the swivel ring 107 changes at a speed increase from minimum to maximum by about 2 ° to 4 °, in particular under the condition of an approximately constant pressure in the engine room. This change means that the tilt angle is practically constant under the given conditions. Similarly, then the piston stroke is practically constant.

For spring constant of acting on the swash plate return spring is usually set optimally for a certain speed. At high speed fluctuations, this has a disadvantageous effect in conventional compressors, due to the relatively large spread of the control characteristics between minimum and maximum speed.

According to the invention, however, the control characteristics are very close to each other and run almost parallel to each other. Accordingly, an optimal spring constant for a relatively narrow characteristic bundle can be set, with the result that the spring constant for all speeds between minimum and maximum speed is set almost optimally or can be adjusted. It is about 40 to 90 N / mm, in particular about 40 to 70 N / mm.

Finally it should be noted that at the outset calculating the mass moments of inertia, in particular the Deviationsmoments preferably also a so-called Steiner component (y _s · z _s · m) should be taken into account under the consideration of the moment of deviation is as follows.: $${\mathrm{J}}_{\stackrel{\mathrm{~}}{\mathrm{Y\; Z}}}\mathrm{=}{\mathrm{J}}_{\mathrm{Y\; Z}}\mathrm{+}{\mathrm{y}}_{\mathrm{s}}\mathrm{\cdot }{\mathrm{z}}_{\mathrm{s}}\mathrm{\cdot }\mathrm{m}$$

For small tilt angles of the swash plate, eg a swivel ring, the proportion J _{yz is} smaller than the Steiner proportion y _s · z _s · m. The proportion J _YZ always regulates the compressor, while the proportion y _s · z _s · m always corrects (set by the position in the quadrant Q2, Q4 according to FIG Fig. 12 ).

From the above considerations, it follows that the moment of deviation has two opposing influence components, i. both an up and down.

• y_s · z_s · m > J_YZ (aufregelnd), und für
• α> α_G umgekehrt (d.h. abregelnd).

The corresponding proportions are effective after exceeding a limit tilt angle α _G , where for α <α _G :

• y _s · z _s · m> J _YZ (aufregelnd), and for
• α> α _G reversed (ie, offsetting).

Claims (13)

1. Axial piston compressor, 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 in a cylinder block at least one piston (118) which moves axially back and forth as a part moved in translation and at least one tilt plate which drives the pistons and rotates together with the drive shaft (104) as a part moved in rotation,
   characterised in that
   the geometry and dimensioning of all parts moved in translation, on the one hand, and all parts moved in rotation, on the other hand, are such that, for any desired tilt angles (α) of the tilt plate (107), the moment M_k,ges due to the masses moved in translation is approximately equal to the moment M_SW due to the moment of deviation, the speed-of-rotation-dependent characteristic curves of the drive mechanism chamber pressure difference (p), relative to the suction pressure, set against the tilt angle (α) of the tilt plate (107) either intersecting at one point or converging at one point.
2. Compressor according to claim 1,
   characterised in that
   the tilt angle (α) lies between a predetermined minimum tilt angle (α_min) and a predetermined maximum tilt angle (α_max).
3. Compressor according to claim 1 or 2,
   characterised in that
   the balancing of moments M_k,ges = M_sw is set for a predetermined tilt angle (α), especially for the following tilt angles: $$\mathrm{\alpha }\mathrm{=}\left({\mathrm{\alpha }}_{\max }\mathrm{-}{\mathrm{\alpha }}_{\min }\right)\mathrm{/}\mathrm{2}\mathrm{,}$$

   

   or $$\mathrm{\alpha }\mathrm{=}{\mathrm{\alpha }}_{\max },$$

   

   or even a predetermined virtual tilt angle $$\mathrm{\alpha }>{\mathrm{\alpha }}_{\max }\mathrm{.}$$

   
4. Compressor according to one of claims 1 to 3,
   characterised in that
   the centre of gravity of the tilt plate (107) is located on the tilt axis (x) thereof.
5. Compressor according to one of claims 1 to 3,
   characterised in that,
   given division of the space surrounding the drive shaft and the tilt plate into four quadrants (Q1, Q2, Q3, Q4), the centre of gravity of the tilt plate (107) is offset either into a first, front quadrant (Q1) delimited by the drive shaft (104) and the front face of the tilt plate (107) including the piston support and facing the pistons, or into a second, front quadrant (Q2) located on the side opposite the first quadrant (Q1) relative to the drive shaft (104), or into a third, rear quadrant (Q3) arranged relative to the tilt plate (107) at the height of the second quadrant (Q2) behind the tilt plate (107), that is to say on that side of the tilt plate (107) which is remote from the pistons, or into a fourth, rear quadrant (Q4) arranged relative to the tilt plate (107) at the height of the first quadrant (Q1) behind the tilt plate (107), that is to say on that side of the tilt plate (107) which is remote from the pistons.
6. Compressor according to one of claims 1 to 5,
   characterised in that
   it is down-regulatable in the relatively high speed of rotation range and up-regulatable in the relatively low speed of rotation range (Figs. 15a, 16, 17, 18).
7. Compressor according to claim 5 or 6,
   characterised in that
   the location of the centre of gravity moves, with a change in the tilt angle of the tilt plate (107), from an up-regulating quadrant (Q2, Q4) into a down-regulating quadrant (Q1, Q3) or vice-versa.
8. Compressor according to one of claims 1 to 7,
   characterised in that
   the piston stroke and/or the tilt angle of the tilt plate (107) is substantially constant in the case of changes in the speed of rotation.
9. Compressor according to one of the preceding claims,
   characterised in that
   the point of intersection of the characteristic curves separates the up-regulating from the down-regulating speed of rotation range.
10. Compressor according to one of claims 1 to 9,
    characterised in that
    the characteristic curves for different speeds of rotation run approximately parallel to one another.
11. Compressor according to one of claims 1 to 10,
    characterised in that
    the tilt angle (α) of the tilt plate changes by about 2° to 4° in the event of an increase in the speed of rotation from minimum to maximum, especially under the condition of an approximately constant pressure in the drive mechanism chamber.
12. Compressor according to one of claims 1 to 11,
    characterised in that
    the spring constant of the restoring spring (117) acting on the tilt plate is between about 40 and 90 N/mm, especially about 40 to 70 N/mm, the selected spring constant having been optimised for a group of regulation characteristic curves.
13. Compressor according to one of claims 1 to 12,
    characterised in that
    the moment of deviation, taking into account a so-called Steiner component, includes both an up-regulating and a down-regulating term, those terms predominating, in each case, after a threshold tilt angle (α_G) of the tilt plate (107) has been exceeded, especially, in the case of
    α < α_G in up-regulating manner, and
    α > α_G in down-regulating manner.

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