EP1766234A1

EP1766234A1 - Axial piston compressor, in particular a compressor for the air conditioning system of a motor vehicle

Info

Publication number: EP1766234A1
Application number: EP05749686A
Authority: EP
Inventors: Otfried Schwarzkopf
Original assignee: Valeo Compressor Europe GmbH
Current assignee: Valeo Compressor Europe GmbH
Priority date: 2004-06-16
Filing date: 2005-06-06
Publication date: 2007-03-28
Also published as: WO2005124150A1; US20110164994A1; US8230773B2; DE102004029021A1

Abstract

The invention relates to an axial piston compressor, especially a compressor for the air conditioning system of a motor vehicle, said compressor comprising a housing and a compressor unit which is arranged in said housing, is driven by a drive shaft, and is used to suction and compress a coolant. The compressor unit comprises pistons that axially move back and forth in a cylinder block, and a pivoting plate (10) (pivoting ring, oscillating plate, or swash plate) that drives the pistons and rotates with the drive shaft (104). The pivoting plate (10) and/or a pivotable part associated therewith comprises points (14, 15) with reduced material collection and/or points which are made of a material which is different from the material from which the rest of the pivoting plate (10) and/or the pivotable part thereof is made. Said points have a targeted influence of the control behaviour of the compressor such that in an area having a smaller tilting angle than the pivoting plate (10) and/or the pivotable part thereof, in particular, in the tilting angle area of between 0° to 8°, in particular 0° to 3°, essentially rectified torque is obtained in the same direction as the adjustment torque of the pivoting plate (10) such that the tilting torque of the pivoting plate (10) is increased in the above-mentioned predetermined tilting angle area (acceleration control of the compressor).

Description

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

Description

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

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

A somewhat different design of an axial piston compressor is for example in the

DE 198 39 914 AI described. The swivel plate is designed as a swash plate, a non-rotatable receiving plate which is mounted opposite the swash plate being arranged between the swash plate and the pistons.

The compressor shown in FIG. 13 is known from EP 1 172 557 A2. This has a swivel plate device with a swivel plate in the form of a swash plate 118, to which pistons 120 are articulated via sliding blocks 121. Furthermore, the swivel plate device has a support device which simultaneously transmits a torque between a drive shaft 114 and the swash plate 118 as a driver component.

A first driver component 117 fastened to the drive shaft 114 in the form of a bearing of the driver component, which is designed as a receiving bore, is arranged at a considerable distance next to the swash plate 118, and a second driver component 119, which engages in the first articulated manner, is the lateral extension of the

Swash plate 118 formed. The above-described construction of the swash plate in the form of the paired driver components 117 and 119 ensures an exposed center of gravity of the swash plate device. The center of gravity removed from the tilting axis and also the tilting joint causes an imbalance, since the engine can only be balanced for a preferably swashplate tilting angle. It should be noted that the center of gravity moves depending on the tilt angle at a considerable distance from the tilt joint, which is the center of the pivoting movement. The swash plate 118 also has a thickened hub part and, as explained above, has a relatively large moment of inertia caused by the driver components 117 and 119 with a center of gravity far away from the tilting axis, so that a sudden change in the rotational speed with a corresponding inertia becomes one Inclination adjustment of the swash plate 118 leads. Furthermore, the center of gravity essentially determines a control behavior. The control behavior is influenced in such a way that the compressor regulates strongly, ie the inertial forces of the swash plate and its center of gravity cause a deviation moment J, which in turn generates a tilting moment M _sw = J x U) ² . The tilting moment mentioned above always counteracts the deviation moment J. As a rule, in the case of compressors according to the prior art, this means a reduction in the angle of tilt, particularly in the working range at medium and large angles of tilt. In general, of course, different deviation moments act on a component, the deviation moment mentioned here being the deviation moment relevant for the tilting movement of the swash plate. This moment of variation is caused by the only degree of freedom in the system that is caused by the tilting joint.

A construction such as that described above is implemented, for example, in the series compressor 6SEU 12 C from DENSO, in which R134a is used as a refrigerant. The (relevant) deviation moment J of the swashplate causes a tilting moment M _sw around the center of the tilting movement of the swashplate, which is effective at least in the area of medium and larger swashplate tilt angles such that the tilting angle of the swashplate attempts to decrease. The inertial forces of the pistons (via their deflection) cause a tilting moment M _k tot on the swash plate, which is also effective around the center of the tilting movement of the swash plate. In contrast to the tilting moment of the swash plate M _sw , the tilting moment generated by the pistons acts in the direction of an increase in the tilt angle of the swash plate. The center of gravity of the system, which lies outside the swivel plate's tilt or pivot point, additionally supports the effect of the pistons. The effect caused by the center of gravity is generally included in the calculation of the (total) moment of deviation, where it is taken into account via a so-called Steiner component.

With regard to the mentioned compressor 6SEU 12 C from DENSO, it should be noted that the mass of a swivel plate cannot be increased arbitrarily in order to change the control behavior of a compressor. This is because, in the case of the compressors of the type described, the center of gravity of the swivel plate is generally at a clear distance from the swivel joint of the swivel plate. This construction The main reason is that in addition to a suitable guide on the drive shaft, the swivel plate must be coupled to the drive shaft or a component connected to the drive shaft via an adjusting mechanism (driver component).

The mentioned distance from the center of gravity of the swivel plate and the tilt joint of the same leads to an imbalance of the engine, in particular depending on the swivel plate tilt angle (the center of gravity moves "like a swing" below the tilt joint) and, in the worst case, leads to an up-regulating property ( so-called "center of gravity").

Future compressors should not have an exposed center of gravity in the area of the swivel plate and the unbalance due to the engine, which is caused in particular by the swivel plate, should be low or ideally zero.

In general, it is the following moments that influence the tilting of the swivel plate in the center of the tilting movement of the swivel plate. The direction of the moment is given in brackets, with (-) regulating (in the direction of the minimum stroke) and (+) regulating (in the direction of the maximum stroke).

Moment due to gas forces in the cylinder rooms (+) moment due to gas forces from the engine room (-) moment due to a return spring (-) moment due to a spring (+) - moment due to rotating masses (-); including moment due to center of gravity (e.g. swivel plate: tilting position φ center of mass): can be (+) or (-) moment due to the translationally moved masses (+)

In the event of speed fluctuations and at the same time largely constant operating conditions, only the latter two moments, namely the moment due to the rotating masses and the moment due to the translationally moving masses, influence this Control behavior. The balance of the forces and moments around the center of the tilting movement of the swivel plate is particularly important here.

In the case of compressors of a modern design, it is desirable to provide an uplifting moment in the area of small swivel plate tilt angles, while a clearly regulating torque is favored for the swivel plate at medium and larger tilt angles.

In this context, reference is made to EP 0 809 027, in which it is pointed out that it is desirable for compressors to provide constant regulation of the delivery rate. In the aforementioned publication it is proposed to design the kinematics of a compressor so that the regulating tilting moments acting on the swivel plate of the compressor clearly dominate compared to the regulating tilting moments.

It should be pointed out that the term “delivery rate” is relatively fuzzy. The delivery rate could be regarded as constant if, for example, the tilting angle of the swashplate is halved when the speed is doubled. The delivery rate would thus be geometrically constant. Of course, other parameters also have an effect the delivery rate if the tilt angle of the swivel plate changes, e.g. delivery rate, oil spill or the like.

The resetting torque of the swivel disk is used for constant control of the delivery rate at changing speeds of rotation, since the swivel disk counteracts its inclined position due to the dynamic forces on the rotating disk part. This behavior can be supported by the force of a spring, so that the delivery rate that increases with increasing rotational speed or rotational speed is at least partially compensated for by resetting the inclined or swivel position of the swivel plate.

For a better understanding, the described tilting behavior as a result of a speed fluctuation is shown in FIGS. 1 and 2. Fig. 1 shows the dependence of the engine room pressure difference related to the suction pressure over the tilt angle o or "alpha" the swashplate. The following pressures were assumed for the calculation:

High pressure 120 bar and suction pressure 35 bar.

Speeds were still calculated:

600 rpm, 1200 rpm, 2500 rpm, 5000 rpm, 8000 rpm and 11000 rpm.

However, only five of the six calculated courses can be seen in FIG. 1. This is because the curves for the speeds of 600 rpm and 1200 rpm are essentially completely one above the other (due to a lack of dynamics); Therefore, the "speed-independent delivery rate" promoted in the prior art is more of a wish that cannot be met with the measures described.

From the diagram according to FIG. 1 it can be clearly seen that there are courses which cause the swivel plate to be displaced to larger tilting angles when the speed increases. It should be mentioned that Fig. 1 is only to be regarded as an example with a simple geometry. However, the trend shown also applies to more complex geometries. The calculation was based on a swivel ring with a predetermined inner and outer diameter and a predetermined height.

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

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

Furthermore, the swivel ring preferably has a mass moment of inertia of J ₃ - J _ζ = (r _a ² 2

+ r, ² ), which is larger than 200,000 gmm ² , preferably about 400,000 - 500,000 gmm ² . The derivation of the so-called deviation moment is given below, which is decisive for the tilting of the swivel plate or a swivel ring, and in the case shown is solely responsible for the tilting of the swivel plate or swivel ring, provided that the center of gravity of the swivel plate or . of the swivel ring both in the tilt point and in the geometric center of the swivel disk or swivel ring. This is an ideal design case to be aimed for. The following generally applies to the derivation of the moment of deviation with reference to FIG. 3:

J_ _z = -J _j Cθsα ₂ cosα ₃ - J ₂ cosß ₂ cosß ₃ -J ₃ cosγ ₂ cosγ ₃ α, = 0 ß, = 90 ° directional angle of the x-axis

Yl = 90 ° with respect to the main axes of inertia ξ η -ζ

αα ₂₂ == 9900 °° ßa = ψ Direction angle of the y-axis compared to the

Jl = 90 ° + ψ main axes of inertia ξ η -ζ

α ₃ = 90 ° ßs = 90 ° - -Ψ Direction angle of the z-axis compared to the

Ϊ3 = Ψ main axes of inertia ξ η -ζ

J_ = J _η = ^ (r _a ² + r, ² + ^) = k = ^ (*. ² + *, ² )

(Note: J, «2 J ₂ goal: J_ _z should have a certain size JT r J ₃ TJ ₂ inevitably increases!)

Deviation moment J_ _z = -J ₂ cosψ sinψ + J ₃ cosψ sinψ

Regardless of Fig. 3: Torque due to the mass force of the pistons ß, = θ + 2π (i-1) ¹

Zi = R ^• ω2 tanα cosß, F _m , = m _k ^• z,

M (F = m _k ^• R ^• cosß, ^• z, n

M _kjges = m _k R ^ z, - cosß,

Moment Msw due to deviation moment M _sw = J _yz - ω ² _ msw msw h ²

Jyz - {- ^ - ( ^r * ^{+ r} >) ^"~ 7-- ( ^r a ^{+ r} . ⁺ Y)} ^{cosα smα} msw J _yz = - sin2α (3r _a ² + 3r, ² - h ² )

M _sw ≥ M _kg . respectively.

[ω ² R ^{2 •} m _k tanα ^ cos ² ß ≤ ω ² sin2α (3r _a ² + 3r, ² -h ² )], = ₁ 24

The sizes used above mean what follows:

θ angle of rotation of the shaft (whereby the above and following considerations are assumed for the sake of simplicity for θ = 0) η number of pistons R distance of the piston axis from the shaft axis ω shaft speed α tilt angle of the swivel ring / swivel plate mk mass of a piston including sliding blocks or sliding block pair 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 p density of the swivel ring

V Volume of the swivel ring ßi Angular position of the piston i zi Acceleration of the piston i Fmi Mass force of the piston i (including a pair of sliding blocks)

M (Fmi) moment due to the mass force of the piston i

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

Msw moment due to the set-up moment of the swivel ring / swash plate or due to the moment of deviation (J _yz ) J = f (p, r, h) moment of inertia

Specifically, FIG. 1 was based on the following determination of the tilting moment of the swivel or swash plate, with α being varied from 0 ° to 16 °:

Tilting moments πt determinationun bevel disk t eta 0 0.00 π n (p) 7 - beta 1 Jz 208436 R 29 [mm] beta 1 0.0 0.00 n 2500 (1 / miπ) beta 2 51.4 0.90 (Jx =) Jy 106137 alp a 16 0.28 π beta 3 102.9 1.80 mk 45 [g] beta 4 154.3 2.69 Jyz 27105 k.ges 315 [gl beta 5 205.7 3.59 beta 6 257.1 4.49 omega 262 msw 230 [g] beta 7 303 , 6 5.39 ra 37 ri 21 10 rho 7.9

29154 Fmi i R fr.eing 30 Fmi 1 25.6 R f (ra; ri) 29 Fmi 2 16.0 Fmi 3 -5.7 Fmi 4 -23.1 Fmi 5 -23.1 sin2 (alpha 0.5299 Fmi 6 -5.7 taπ (alpha) 0 , 2867 Fmi 7 16.0

M (Fmi) M (Fmi) 1 0.74 M (Fmi) 2 0.29 M (Fmi) 3 0.04 M (Fmi) 4 0.50 M (Fmi) 5 0.60 M (Fmi) 6 0.04 M (Fmi) 7 0 , 29 n 2500 [1 / miπ] alpha 16 π | k, tot 2, 60321 | bw 1.8578 |

It can be seen that the influence of the piston masses predominates and that the regulating behavior of the swashplate or swivel plate results with increasing speed.

It is therefore the case M _kg "> M _sw 2 shows a diagram for an almost identical engine, this diagram being obtained according to the following calculation scheme, α being varied from 0 ° to 16 °:

Tilting moment determination uπo Sehrios disc theta 0 0.00 [ ^* ] n (p) 7 - beta i Jz 375185 R 29 [mm] beta 1 0.0 0.00 n 2500 [1 / min] beta 2 51.4 0.90 (Jx = ) Jy 198786 alpha 16 0.28 π beta 3 102.9 1.80 mk 45 [g] beta 4 154.3 2.69 Jyz 46739 mk.ges 315 [g] beta 5 205.7 3.59 beta 6 257.1 4.49 omega 262 msw 415 [g] beta 7 308.6 5.39 ra 37 [mm] ri h rho

Fmi i R fr.eing 30 Fmi 1 25.6 R f (ra; ri) 29 Fmi 2 16.0 Fmi 3 -5.7 Fmi 4 -23.1 Fmi 5 -23.1 sin2 (alpha 0.5299 ^' Fmi 6 -5.7 tan (alpha) £ 0.28 Fmi 7 16.0

, M (Fmi) i M (Fmi) 1 0.74 M (Fmi) 2 0.29 M (Fmi) 3 0.04 M (Fmi) 4 0.60 M (Fmi) 5 0.60 M (Fmi) 6 0, 04 M (Fmi) 7 0.29 n 2500 M / mir:] alpha 16 π | Mk, tot 2, 60321 | Msw 3.2034 |

Here we have the case M _k <M _sw . This calculation scheme shows that the thickness or height of the swash plate or swash plate has been increased from 10 mm (FIG. 1) to 18 mm (FIG. 2) compared to the calculation for FIG. 1. The consequence of this is that the relevant moment of inertia J. increases comparatively to approximately twice the value. A regulating behavior of the swivel disk engine can be seen in FIG. 2. This trend is indicated by the arrow "n" in FIG. 2, where "n" means the speed of the swivel disk or drive shaft. The arrow “n” in FIG. 1 has the same meaning, of course, only the arrow is directed there in the opposite direction, as a result of which an increase in speed should be indicated.

1 shows the prior art. The regulating behavior according to FIG. 1 can often be determined in the case of current R134a series compressors. With more recent developments, one tries to change this trend into the opposite, namely according to Fig. 2.

In Fig. 4 the case is shown in which the regulating tilting moments due to the mass moments of inertia / deviation moments of the swivel plate or the swivel plate assembly are dimensioned such that a control behavior results in which the tilt angle of the swivel plate remains almost constant when the speed increases , or is reduced, whereby at least part of the increasing delivery rate resulting solely from the increase in speed is compensated.

4 is based on the following calculation:

n 2500 [1 / min] alpha 1 π Mk.ges 0.1585 Msw 0.1714 2500 [1 / miπ] alpha 8 ["] Mk.ges 1.2759 Msw 1.3540 n 2500 [1 / miπ] alpha 16 π Mk, tot 2.6032 Msw 2.6032 n 11000 [1 / min] alpha 1 π Mk.ges 3.0679 Msw 3.3191 n 11000 [1 / miπ] alpha 8 π Mk.ges 24.7014 Msw 26, 2141 π 11000 [1 / miπ] alpha 16 π Mk.ges 50.3983 | Msw 50.3972

FIGS. 5, 6 and 7 show the tilting moments M _sw , M _t corresponding to FIGS. 1, 2 and 4 as well as the sums of the two aforementioned moments for a speed as a function of the tilting angle of the swivel plate or the geometric stroke volume of the compressor. In FIG. 5, the regulating characteristic of the compressor can be clearly seen on the basis of the sum of the moments in the positive range, while in FIG. 6 the sum of the moments is negative for all tilt angles of the swash plate. A compressor that follows the course of the moments according to FIG. 6 has regulating characteristics. Finally, reference is made to FIG. 7, which shows a torque curve with approximately identical torque of M _{k tot} and M _sw , so that the _total torque is approximately zero for all tilt angles of the swash plate.

8 a shows the sum M _sw + M _{k gcs} for different speeds. FIG. 8a corresponds to FIGS. 1 and 5, and clearly shows the total torque that increases as the rotational speed increases.

8b shows the above-mentioned sum for the case dealt with in FIGS. 2 and 6, it being clear that an increasing regulating torque is obtained with increasing speeds. It should be noted that in the case of FIGS. 8a and 8b, the moment of variation of the swivel plate is zero at the tilt angle 0 °. This means that in this example the swashplate and tilt joint and center of gravity coincide, whereby no exposed center of gravity occurs.

The diagram in FIG. 8c shows the behavior of a compressor in which the deviation _torque and the resulting tilting moment M _sw + M _{k gcs are} not equal to zero at a _{swash plate} tilt angle of 0 °. This means that the compressor start is supported by a moment, but the following problems arise: Because M _sw + M _{k gcs is} not equal to zero at a very small tilting angle of, for example, 0 °, the amount mentioned is reflected over the whole Tilt angle range again. Accordingly, the curve is shifted approximately parallel to a curve with a starting value of M _sw + M _{k ges} equal to zero. It should also be borne in mind that in the region of larger tilt angles the upward effect is amplified by the additional tilting moment (cf. FIG. 8a). Because with modern compressors the trend towards one

Control behavior goes, which rather follows the course of Figures 2 and 6 or 4 and 7, an adjusting behavior in the region of larger tilt angles is undesirable.

The object of the present invention is to provide a compressor in which the deflection of the swash plate from a range of small tilt angles is supported in the simplest possible manner.

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

An essential aspect of the invention lies in providing reduced material accumulation on the swivel plate or a swiveling portion of the same points and / or points which consist of a material which is different from the material of which the rest of the swivel plate or swivel part is made is the same. These points have the effect of specifically influencing a control behavior of the swivel plate or the compressor, in such a way that, in particular, in a range of small tilt angles of the swivel plate or the swiveling portion thereof in a tilt angle range of 0 ° to 8 °, in particular 0 ° to 3 °, a set-up torque of the swivel plate is obtained in such a way that the tilt moment of the swivel plate in the aforementioned tilt angle range compared to a conventional swivel plate, in particular in comparison to a swivel plate according to the prior art Technology is increased and a tilt-up of the swivel plate or the swiveling portion of the same, which promotes the compressor, is favored. Such a constructive measure makes it possible to support the tilting of the swivel plate at small tilt angles when the compressor is to be regulated. In clutchless compressors, a certain minimum piston stroke, which is required in the case of compressors according to the prior art in order to provide a pressure on the high pressure side which is sufficient to regulate the compressor, can be reduced or become completely unnecessary. In the case of compressors that are not permanently subjected to speed, that is to say are connected to a drive via a clutch, such a construction makes it easier for the compressor to start up or enables it in the first place.

In a preferred embodiment, the swivel plate is ring-shaped, that is to say in the form of a swivel ring. The geometry of a swivel ring is particularly well suited for the attachment of places with reduced material accumulation and / or places that are made of a different material. If a compressor has a swash plate, it is designed to be narrower than a swivel ring which has the same predetermined mass moment of inertia at a desired or required predetermined mass moment of inertia. Accordingly, the design measures described in more detail above are particularly easy to implement on a swivel ring. Furthermore, when the swivel plate is designed as a swivel ring, it can be ensured in a simple manner that the stability and / or the strength of the swivel plate due to the points of reduced material accumulation and / or the steep parts on which the swivel plate or its swiveling portion consists of one material , which differs from the rest of the swivel plate or its swiveling portion, is only insignificantly or not at all impaired by the design measures. This ensures the longevity of the compressor according to the invention, since a swivel plate designed in this way is subject to little wear. The locations of reduced material accumulation preferably include bores and additionally or alternatively grooves. These are features that are easy to implement in terms of design.

The material of the locations, which consist of a material that is different from the material from which the essential rest of the swivel plate or the swiveling portion thereof is made, in a further preferred embodiment, has a lower density than the material which consists of the essential rest of the swivel plate or the swiveling portion thereof. Preferably, the aforementioned lower density material has a density less than about 7.83 g / cm ³

(Density of steel), the choice preferably being made of a material with a density of approximately 1.5 g / cm ³ . Due to the lower density of the material of the points, which consist of a material that is different from the material from which the essential rest of the swivel plate or the swiveling portion thereof is made, on the one hand the desired control behavior is favored, while the stability of the swivel ring or the swivel plate is not reduced. A particularly easy to manufacture embodiment has points made of plastic material; the density of plastics is of the order of about 1.5 g / cm ³ .

In a further preferred embodiment, the moment of variation of the swivel plate or of the swiveling portion thereof is zero for a predetermined tilt angle in the range of small tilt angles, in particular a tilt angle in the tilt angle range from 0 ° to 8 °, in particular 0 ° to 3 °. Optionally, the deviation torque of the swashplate or the pivotable portion of the same favors a de-energization of the compressor at tilt angles that are greater than the predetermined tilt angle, while for angles smaller than the angle for which the deviation torque becomes zero, the aforementioned deviation torque regulates the Compressor supports. Such a control behavior corresponds to the requirements placed on a modern axial piston compressor, particularly when used in the air conditioning system of a motor vehicle.

The center of gravity of the swivel disk, which, as described in more detail above, has points of reduced material accumulation and / or points made of a different material are as the rest of the swivel plate, in a further preferred embodiment it does not differ noticeably from the center of gravity of a swivel plate which is single-material and / or without reduced material accumulation, that is to say solid throughout. Furthermore, the center of gravity of the swivel disk lies on a tilt axis assigned to it. This ensures that a compressor according to the invention runs smoothly.

The swivel plate is preferably made of cast iron, which enables it to be produced easily. In particular, gray cast iron (GG), spheroidal cast iron (GGG), cast steel or cast aluminum are used. In a further preferred embodiment, at least some of the points of reduced material accumulation, for example grooves, are formed as part of the casting of the swivel plate. As a result, the points of reduced material accumulation can be realized in a simple manner already when the swivel plate is manufactured. In a further preferred embodiment, at least part of the steep amount of reduced material accumulation is formed by machining. Processing (additional or alternative to casting) with machining means ensures that the swivel plate is fine-tuned. In contrast to casting, machining is an increased processing effort, but can achieve good results, especially if the required precision is high. Furthermore, as already mentioned, a combination of casting and subsequent machining is also conceivable, in particular in order to obtain the necessary fine tuning or balancing of the swivel plate.

The points of reduced material accumulation and / or the points which consist of a different material from the rest of the swivel plate or the swivelable part of the same are arranged symmetrically to one another in a further preferred embodiment. A special position occupies a point-symmetrical arrangement of the respective points with respect to the tilt joint. This constructive measure also ensures that the swivel plate runs smoothly. Unbalance and a wear-promoting run can be avoided.

Preferably, an average radius and / or an average height of the swivel disk or the swiveling portion thereof are dimensioned such that in the area of the middle and Large tilt angle, in particular in the range of tilt angles that are greater than or a predetermined tilt angle for which the deviation torque of the swivel plate becomes zero, when the swivel plate is rotated, counteracting forces that counteract the swivel movement of the swivel plate via the pistons on the swivel plate acting forces causing a more far-reaching pivot movement, so that the piston stroke decreases with increasing speed by such an amount that an approximately constant delivery rate is established. As mentioned, this constructive measure is designed in such a way that it comes into play in the range of medium and large tilt angles of the swashplate, while at the smallest and small tilt angles, i.e. in a range up to 8 °, more precisely up to the zero crossing of the deviation torque depending on Tilt angle, a tendency of the swivel plate that supports the adjustment can be observed.

The control characteristic of a compressor according to the invention thus corresponds to the requirements of a modern compressor as used in air conditioning systems of motor vehicles.

The center of gravity of the swivel disk or the swivelable portion thereof preferably lies in or at least close to the axis of the drive shaft, where in particular the center of a tilt joint or its tilt axis is also located. This in turn ensures that a compressor according to the invention runs smoothly without an imbalance occurring.

When the swivel plate is designed as a swivel ring, an inner and an outer diameter are preferably selected to a maximum within the outer conditions. The external conditions can be, for example, the inside diameter of the engine compartment, sufficient support for sliding blocks of a joint arrangement effective between the piston and swivel plates, or similar limiting or regulating factors. It should be noted at this point that in all of the above embodiments, the desired control behavior of the compressor is not primarily achieved with the component mass, but rather by taking into account or utilizing the moment of inertia of the swivel plate arrangement, which depends on its geometry. In the preferred embodiment now discussed, in which the radii of the swivel ring or the diameter of the swivel ring is selected to be the maximum, a geometry of the swivel plate is available which ensures a combination of low component mass and (sufficiently) large moments of inertia. The desired mass moment of inertia can also be influenced by a suitable choice of the swash plate thickness.

The swivel disk or the swiveling portion thereof preferably consists of two or more different materials which determine the mean radius for the calculation of the moment of inertia, the different materials being separated radially and / or axially from one another. This is particularly the case such that in the case of a swivel ring, an outer or inner partial ring made of a first material, e.g. a higher density material such as lead or the like. Is formed within an outer or inner circumferential groove of an inner or outer part ring, which is made of harder and wear-resistant material such as steel, ceramic or the like. In this way, on the one hand, the moment of inertia of the compressor according to the invention can be optimized and, on the other hand, the introduction of places with reduced material accumulation or places of another material can be implemented relatively easily. This is particularly the case if the outer ring is made of lead, since this is a soft, easy-to-work material. When the swivel disk or the swiveling portion of the swivel disk is formed from several different materials

The radially outer parts preferably consist of a denser material, while the radially inner parts consist of a less dense material. This constructive measure also ensures an optimal distribution of the moment of inertia of the swivel plate.

The invention is described below in terms of further advantages and features by way of example and with reference to the accompanying drawings. The drawings show in:

9a shows a “tube” of a swivel ring for a compressor according to the invention, ie an as yet unfinished swivel ring in a perspective oblique view; 9b shows the swivel ring from FIG. 9a in a sectional view;

10a shows a first embodiment of a swivel ring for a compressor according to the invention in a perspective oblique view;

10b shows the swivel ring from FIG. 10a in a sectional view;

11a shows a second embodiment of a swivel ring for a compressor according to the invention in a perspective oblique view;

11b shows the swivel ring from FIG. 11a in a sectional view; and

FIG. 12 shows the deviation torque of the swivel rings according to FIGS. 9a to 11b as a function of the tilt angle of the respective swivel ring.

For both preferred embodiments to be described in more detail below, the compressor according to the invention comprises an engine housing which is cup-shaped and has a cylinder block connected to its peripheral edge. Several, preferably five, six or seven axially reciprocating pistons are arranged within the cylinder block, the distribution of the pistons being uniform around a central axis of the housing. A drive shaft driven by a pulley extends through the bottom of the pot-shaped housing into the housing interior or into an engine compartment. The drive shaft is mounted on the one hand in the area of the bottom of the pot-shaped housing and on the other hand within the cylinder block. Inside the engine room is a swivel plate mechanism, which among other things comprises a swivel ring, by means of which the rotary movement of the drive shaft is converted into an axial movement of the pistons. In addition, intake and exhaust valves are arranged between a cylinder head and the cylinder block. The above structure is largely known from the relevant prior art.

An example of the swivel plate in the form of a swivel ring 10 on which the two preferred embodiments of the present invention are based is shown in FIGS. 9a and 9b. It is a "blank" that is not in this form in a compressor according to the invention can be found; fundamental considerations can, however, be explained in a simple manner using such a “simplified” representation. Furthermore, a comparison of the moments of variation of the swivel rings of compressors according to the invention with that of a swivel ring according to FIGS. 9a and 9b is also drawn below in order to take advantage of an embodiment according to the invention to be able to explain illustratively.

The swivel ring on which the two embodiments are based is made of cast iron and has an inside diameter 11 of 42 mm and an outside diameter 12 of 74 mm with a height 13 of 18 mm. It should be noted at this point that the dimensions mentioned above are in no way to be understood as restrictive, but merely provide an example of the dimensions of such a swivel ring. The abovementioned variables are therefore used primarily for the orientation of the reader, but not for restricting a compressor according to the invention to certain dimensions. The idea of the invention itself is of course independent of any dimensions of the compressor.

In order to obtain a moment of deviation of the swivel plate which is not equal to zero at a tilt angle of 0 ° and which is equal to zero at a predetermined tilt angle not equal to 0, in the two preferred embodiments of a compressor according to the invention, positions are reduced in the respective swivel rings Material accumulation is provided, which in the first preferred exemplary embodiment according to FIGS. 10a and 10b in the form of bores 14 or bore-like, that is to say cylindrical recesses. In the second preferred exemplary embodiment according to FIGS. 11a and 11b, the cutouts are in the form of grooves 15.

As can be seen from FIGS. 10a and 10b and 11a and 11b, the cutouts are arranged symmetrically with respect to an x-axis 16, the center of gravity of the swivel ring being formed by the cutouts in the form of bores 14 or grooves 15 compared to that in the figures 9a and 9b "Rohhng" is not changed. In each of the two preferred exemplary embodiments, the center of gravity of the swivel ring 10 lies on the x-axis 16, which at the same time represents a tilt axis assigned to the respective swivel ring 10. Due to the geometrical dimensions, in particular a relatively large height 13 of the swivel ring 10, the locations of reduced material accumulation 14 and 15 do not impair the stability or the strength of the swivel ring 10 if the respective values for this are compared with those of the blank according to FIGS. 9a and 9b compares. The cutouts according to FIGS. 10a to 11b are introduced into the tube during casting, the necessary fine tuning, which ensures that the swivel ring runs without imbalance, being ensured by machining (reworking).

The points of reduced material accumulation in the form of the bores 14 or grooves 15 are provided such that, depending on the embodiment (see also the diagram in FIG. 12, which will be explained in more detail below), at a tilt angle of approximately 1 ° to approximately 2 ° the deviation moment of the swivel ring, which results in a corresponding tilting moment of the swivel ring 10, has a zero crossing. For smaller tilt angles, the aforementioned deviation moment favors tilting of the swivel ring 10 in a direction that adjusts the compressor, while for tilt angles greater than approximately 1 ° to approximately 2 °, the deviation moment favors a regulating tendency of a compressor according to the invention. At this point it should be noted that the regulating tendency in particular can be reinforced if necessary by attaching additional weights or else by a multi-material design of a swivel ring 10 of a compressor according to the invention. In this case, it is particularly advisable that the different materials are separated radially and / or axially from one another, in particular in such a way that an outer or inner partial ring is made of a first material, preferably of a higher density material such as lead or the like. is formed within an outer or inner circumferential groove of an inner or outer partial ring, which is made of harder and wear-resistant material such as steel or ceramic or the like. The radially outer part is preferably made of denser material than the radially inner part.

Of course, it is also conceivable that the recesses in the form of bores or grooves and of course also recesses of any other shape are filled with a material, preferably of lower density, in order to achieve the desired control behavior, and thus locations which are made of a material which is different from that Is material from which the substantial rest of the swivel ring is formed. This The measure serves to maintain the stability of the swivel ring, such an alternative also being of interest, in particular for swash plates in the form of swash plates, since it is precisely with swash plates that recesses which are too large cannot be made without impairing the stability of the swash plate. Furthermore, in the areas of reduced material accumulation, other measures such as struts or the like that maintain the rigidity or strength of the swivel disk or swivel ring 10 are also conceivable.

It should also be noted at this point that the inside and outside diameters are limited within the outside conditions, in the present case by the inside diameter of the engine room, but are selected to be the maximum in each case. The center of gravity of the swivel ring 10 lies within the tolerances on the axis of the drive shaft, which at the same time represents the center of a tilting joint (not shown) or the associated tilting axis, which is identical to the x-axis 16.

Due to the symmetrical distribution of the recesses with respect to the tilt axis, a deviation torque is generated which is not equal to zero at a tilt angle of 0 °. Reference is made here in particular to the position of the respective cutouts, which are provided closer to the upper edge of the swivel ring 10 on one side of the tilt axis and closer to the lower edge of the swivel ring 10 on the other side of the tilt axis. The same applies to recesses in the form of grooves 15, as shown in FIGS. 11a and 11b. From Fig. 11b it can also be seen that the grooves in the present preferred embodiment extend over an angle of 135 ° and have a depth of 18 mm. The values mentioned above are also only to be regarded as illustrative and serve to orient the reader. Of course, they have no significant influence on the basic ideas of the invention.

Finally, the courses of the deviation moments J _yz responsible for the tilting movement of the swivel ring 10 are plotted against the tilt angle α of the swivel ring 10. In this figure, there is a curve 17, which represents the behavior of a swivel ring 10 with grooves 15, and a curve 18, which represents the behavior of a swivel ring 10 with bores 14, in addition to a comparison curve 19, which shows the behavior of a swivel ring without recesses, i.e. one Swivel rings according to Figures 9a and 9b, represented, plotted. As can be seen from the diagrams, the swivel ring without cutouts has a deviation torque over the entire tilting range, which favors a regulating behavior of the swivel ring, while the two swivel rings 10 provided with cutouts show a deviation torque which is in the range of a tilting angle of approximately 1 ° has a zero crossing up to about 2 °. An regulating behavior of the compressor is induced for smaller angles, while a regulating behavior is induced for larger tilt angles of the swivel ring 10. This meets the requirements of a modern compressor. It should be noted that the course of the deviation torque is almost linear as a function of the tilt angle of the swivel ring 10, which ensures an ideal control behavior of a compressor according to the invention.

Although the invention is described on the basis of exemplary embodiments with a fixed combination of features, it also includes the conceivable further advantageous combinations of these features, as are specified in particular, but not exhaustively, by the subclaims. All of the features disclosed in the application documents are claimed to be essential to the invention insofar as they are new compared to the prior art, individually or in combination. B e z u g s z e i c h e n l i s t e

10 swivel ring

11 inner diameter

12 outer diameter 13 height

14 hole

15 groove

16 X axis

17 Deviation moment depending on the tilt angle with recesses in the form of grooves 15

18 moment of variation depending on the tilting angle in the form of bores 14

19 Deviation torque depending on the tilt angle without recesses

Claims

claims

1. An axial piston compressor, in particular a compressor for the air conditioning system of a motor vehicle, with a housing and a compressor unit arranged in the housing and driven by a drive shaft for the suction and compression of a refrigerant, the compressor unit in a cylinder block, axially reciprocating pistons and a piston driving swivel plate (10) rotating with the drive shaft (swivel ring; swashplate or swashplate), characterized in that the swivel plate (10) or a swivelable portion of the same points (14, 15) associated therewith reduced material accumulation and / or Points which consist of a material which is different from the material from which the essential rest of the swivel plate (10) or its swiveling portion is made, these points having a targeted influence on a control behavior of the swivel plate (10), such that that in a range of small tilt angles of the swivel ibe (10) or the pivotable portion thereof, in particular in a tilt angle range from 0 ° to 8 °, in particular 0 ° to 3 °, an installation torque of the swivel plate (10) is obtained such that the tilting moment of the swivel plate (10) in relation to a swashplate without the aforementioned points is increased in the aforementioned tilt angle range (accelerated upward adjustment of the compressor).

2. Compressor according to claim 1, characterized in that the swash plate is annular, i.e. is designed as a swivel ring (10).

3. Compressor according to claim 1 or 2, characterized in that the locations of reduced material accumulations comprise bores (14) and / or grooves (15).

4. Compressor according to one of the preceding claims, characterized in that the material of the locations, which consist of a material which is different from the material from which the substantial rest of the swivel plate or the swiveling portion thereof consists, has a lower density than the material from which the substantial rest of the swivel plate or the swivelable portion thereof is made.

5. Compressor according to one of the preceding claims, in particular claim 4, characterized in that the material of the locations which consist of a material which is different from the material from which the essential remainder of the swivel plate or the swiveling portion thereof consists, has a density that is less than about 7.83 g / cm ³ , preferably about 1.5 g / cm ³ .

6. Compressor according to one of the preceding claims, characterized in that the deviation moment of the swash plate (10) or the pivotable portion thereof for a predetermined tilt angle in the range of small tilt angles, in particular a tilt angle in the tilt angle range from 0 ° to 8 °, in particular 0 ° to 3 °, is zero.

7. A compressor according to claim 6, characterized in that in the case of tilting angles which are greater than the predetermined tilting angle, the deviation torque of the swivel plate or the pivotable portion thereof is effective to reduce the tilting angle, while for tilting angles which are smaller than the predetermined tilting angle it is effective to increase the tilting angle.

8. Compressor according to one of the preceding claims, characterized in that the center of gravity of the swivel plate (10) or the swiveling portion thereof, which or which reduces the points of material accumulation and / or the points from one of the rest of the swivel plate (10) or has the pivotable part of the same different material, largely does not differ from the center of gravity of a swivel plate which is made of single material and / or without reduced material accumulation, the center of gravity of the swivel plate (10) or the swivelable part of the same on a tilt axis assigned to it 16) Lies.

9. Compressor according to one of the preceding claims, characterized in that the swivel plate (10) consists of cast iron, in particular gray cast iron (GG), spheroidal cast iron (GGG), cast steel or cast aluminum.

10. Compressor according to claim 9, characterized in that at least some of the points (14, 15) of reduced material accumulation are cast, i.e. are formed as part of the casting of the swivel plate (10).

11. Compressor according to one of the preceding claims, characterized in that at least some of the points (14, 15) of reduced material accumulation is formed by machining and / or a necessary fine-tuning or balancing of the swash plate (10) or the swiveling portion thereof are achieved by machining.

12. Compressor according to one of the preceding claims, characterized in that the points (14, 15) of reduced material accumulation and / or the points which consist of a material different from the rest of the swivel plate are symmetrical to one another, in particular point symmetrical with respect to the tilting joint, are arranged.

13. Compressor according to one of the preceding claims, characterized in that an average radius and / or an average height of the swivel plate (10) or the pivotable portion thereof are dimensioned such that at medium and large tilt angles, in particular at tilt angles greater than 8 ° , especially with tilt angles greater than 3 °, when the swivel plate (10) rotates, counteracting the swivel movement (increase in the swivel angle) of the swivel plate (10) by means of forces acting on the swivel plate (10) on the part of the pistons which cause a more extensive swivel movement, so that the piston stroke decreases with increasing speed to such an extent that an approximately constant delivery rate is established.

14. Compressor according to one of the preceding claims, characterized in that the center of gravity of the swivel plate (10) or the swiveling portion of the same is in, or at least close to, the axis of the drive shaft, where in particular the center of an associated tilt joint or its Tilt axis (16) is located.

15. Compressor according to one of the preceding claims, characterized in that when the swivel plate (10) is designed as a swivel ring, an inner (11) and outer diameter (12) are each selected to a maximum within the external conditions.

16. Compressor according to one of the preceding claims, characterized in that the swivel plate (10) or the swiveling portion thereof is made of two or more different materials which determine an average radius for calculating the moment of inertia, the different materials being radial and / or are axially separated from one another, in particular in such a way that, in the case of a swivel ring (10), an outer or inner partial ring made of a first material, for example a material of higher density, such as lead or the like, within an outer or inner circumferential groove of an inner or outer Partial ring is formed, which is made of harder and wear-resistant material such as steel, ceramic or the like.

17. Compressor according to one of the preceding claims, in particular according to claim 16, characterized in that the radially outer parts consist of denser material than the radially inner parts when the swivel plate (10) or the swivelable portion thereof is formed from a plurality of materials of different densities.