DE102024203564A1 - Scroll compressor for a refrigerant in a vehicle air conditioning system - Google Patents

Abstract

The invention relates to a scroll compressor (2) for a refrigerant of a vehicle air conditioning system, in particular for carbon dioxide, comprising a first scroll (38) with a base plate and a spiral wall, a second scroll (32) movable relative to the first scroll (38) with a base plate (40) and with a spiral wall which engages in the spiral wall of the first scroll (38) and forms compression chambers therewith, an electric motor drive (4) which is coupled to the second scroll (32) by means of a drive shaft (22) for power transmission, and a bearing plate (8) which is arranged between the drive (4) and the second scroll (32) and which is formed in two parts from an outer part (52) and an inner part (54) which is bordered radially on the outside by the outer part (52) at least in regions, wherein the outer part (52) carries a shaft bearing (28) for the drive shaft (22), wherein the inner part (54) is connected to the second Scroll (32) is coupled, wherein the inner part (54) has an upstanding annular collar (68) with a knurled toothing (70), and wherein the inner part (54) is pressed axially into a receptacle (62) of the outer part (52) in a form-fitting and/or force-fitting manner by means of the knurled annular collar (68).

Description

The invention relates to a scroll compressor for a refrigerant in a vehicle air conditioning system, in particular for carbon dioxide. The invention further relates to a bearing plate for such a scroll compressor.

Motor vehicles are regularly equipped with air conditioning systems that use a system forming a refrigerant circuit to cool the vehicle interior. Such systems generally have a circuit containing a refrigerant. The refrigerant, for example R-744 (carbon dioxide, CO2) or R-134a (1,1,1,2-tetrafluoroethane), is heated in an evaporator and compressed by a (refrigerant) compressor. The refrigerant then releases the absorbed heat via a heat exchanger before being returned to the evaporator via a throttle.

A so-called scroll machine is often used as a refrigerant compressor to compress the refrigerant. The structure and function of such a scroll machine, used as a compressor for the refrigerant in a vehicle air conditioning system, is described, for example, in DE 10 2012 104 045 A1 The essential components of such a scroll machine are two scroll parts (scrolls) that can be moved relative to each other. The system usually also contains oil in droplet form or as a mist, which, after compression, is at least partially separated from the refrigerant (which is usually gaseous after compression). The refrigerant (possibly with oil residues) is then introduced into the air conditioning circuit, while the separated oil can usually be fed to the moving parts within the scroll machine for lubrication.

The scroll components are typically designed as a stationary, fixed scroll (fixed scroll, displacement scroll) and a movable, orbiting scroll (counter scroll, rotor scroll). Both scrolls are fundamentally similar in design and each comprise a base plate (main body, scroll disc) and a spiral-shaped wall (helical wall, scroll wall) extending axially from the base plate. When assembled, the spiral walls of the two scrolls are nested within each other, forming several compression or discharge chambers between the scroll walls, which touch each other in sections.

To drive the movable scroll, an electric motor drive is typically provided, the drive shaft of which (A-side, i.e. output side) is coupled to the movable scroll part by means of an eccentric shaft journal (also: “shaft pin”).

An orbiting movement, here and in the following, is understood in particular to mean an eccentric, circular movement path in which the movable scroll itself does not rotate about its own axis. During operation, the two scrolls are axially spaced from one another as closely as possible, whereby each orbiting movement essentially forms crescent-shaped (compression or delivery) chambers between the spiral walls. As the two scrolls move relative to one another (at least during a compression process), their volume migrates from the outside along the spiral walls toward the central axis of the respective scroll, thereby increasingly reducing (and thus compressing the medium conveyed therein).

The orbiting movement of the movable scroll is typically achieved, among other things, by an anti-rotation mechanism, which prevents the scroll from rotating on its own. This mechanism is usually connected between the movable scroll and a stationary element of the scroll machine. The anti-rotation mechanism is often formed by a number of circular, pocket-like openings ("rings") arranged on a circular path, usually in the movable scroll, and associated pins ("pins"), usually arranged in the stationary element. The pins engage in the circular openings of the movable scroll, each forming a so-called pin-ring contact. During (compressor) operation, the pins slide along the circular opening walls, preventing self-rotation. To reduce friction and improve service life, race rings (sliding rings), for example, are inserted into the openings. Due to this design, the anti-rotation mechanism is also referred to as a "pin-ring system."

The motor shaft is usually mounted in a bearing plate (also called a "center plate") by means of a bearing. The pins of the anti-rotation mechanism are usually fixed (especially force-locked) in the bearing plate.

Carbon dioxide as a refrigerant requires higher pressures than chemical refrigerants (e.g., R-134a), so sufficiently high strength cannot often be achieved with aluminum as the material for the scrolls. A related problem is the connecting components, which are preferably made of aluminum and therefore often exhibit different thermal expansion behavior.

From the applicant’s German application dated 16 February 2024 with the file number 10 2024 201 453.2 For example, it is known to construct the bearing shield in two parts, with an outer part housing the main bearing for the drive shaft and an inner part containing the (anti-rotation) pins. The outer part and the inner part are joined together in a rotationally fixed manner. The outer part also accommodates, for example, a radial shaft seal and joining elements for positioning in a compressor housing.

The inner part is preferably made of a material that has a virtually identical coefficient of thermal expansion to the movable scroll part, ensuring that the anti-rotation mechanism always functions reliably during operation. For example, the inner part is made of gray cast iron, while the outer part is made of aluminum.

Due to the comparatively large joining diameter and the associated thermal expansion, it is difficult to ensure a tight fit between the inner and outer parts using a conventional press fit. The tight fit at low temperatures would increase significantly due to the expansion coefficients. However, to ensure sufficient fixation at high temperatures or the operating temperature, a very high degree of over-pressing must be provided at room temperature. However, due to the high degree of over-pressing, a joining process is generally not possible at room temperature, so the outer part must be additionally heated and/or the inner part cooled. Furthermore, tight fit and surface tolerances are necessary to reduce the fluctuation of joining forces and to remain in the elastic material range at low temperatures.

The invention is based on the object of providing a particularly suitable scroll compressor, especially for use with carbon dioxide as a refrigerant. In particular, a reliable joint for a two-part bearing plate of such a scroll compressor is to be provided. The invention is further based on the object of providing a particularly suitable bearing plate for such a scroll compressor.

The object is achieved according to the invention with regard to the scroll compressor by the features of claim 1 and with regard to the bearing plate by the features of claim 9. Advantageous embodiments and further developments are the subject of the dependent claims (subclaims). The advantages and embodiments cited with regard to the scroll compressor are also transferable mutatis mutandis to the bearing plate, and vice versa.

The scroll compressor has a first and a second scroll, which, in a driven state—i.e., during (compressor) operation—are orbiting relative to one another. For example, the first scroll is designed as a stationary scroll and the second scroll as a movable or orbiting scroll. The first scroll and/or the second scroll is made, for example, from steel or cast iron. Constructing at least the second scroll, and preferably both scrolls, from steel or cast iron enables greater strength compared to scrolls typically made of aluminum and is thus advantageous for the higher pressures when carbon dioxide is used as a refrigerant (particularly compared to chemical refrigerants).

The scrolls or scroll parts each comprise a base plate (bottom plate, scroll plate) and a spiral wall (scroll spiral) extending substantially perpendicularly therefrom along an axial direction. The compression chambers, which are in particular crescent-shaped, are formed between the interlocking spiral walls of the two scrolls (scroll parts). The preferably substantially symmetrical spiral walls of the scroll parts each have a spiral angle of at least 720°, for example.

The scroll compressor also has an electric or electric motor drive, which drives the second scroll via a drive shaft (motor shaft). The drive shaft is rotatably mounted, at least in sections, in a bearing plate between the drive and the scroll parts by means of a (main) bearing. An anti-rotation mechanism is provided to convert the rotational movement of the drive shaft into the orbiting movement of the second scroll.

The anti-rotation mechanism is preferably designed as a pin-ring system in which axially projecting pins (anti-rotation pins) of the bearing plate engage in circular openings in the base plate of the second scroll.

The bearing shield is constructed in two parts, consisting of an outer part and an inner part, which is at least partially radially enclosed on the outside by the outer part. The outer part has a bearing seat for the bearing supporting the drive shaft, while the inner part is coupled to the anti-rotation mechanism.

In particular, the inner part has the raised pins or anti-rotation pins.

According to the invention, the inner part has an axially upstanding annular collar for joining to the outer part. The annular collar is provided, in particular, on the outside with circumferential knurling or knurled teeth, whereby the inner part is pressed axially into a receptacle of the outer part by means of the knurled or knurled-toothed annular collar in a form-fitting and/or force-fitting manner. This results in a particularly suitable scroll compressor.

The conjunction “and/or” is to be understood here and in the following in such a way that the features linked by this conjunction can be formed both together and as alternatives to one another.

A "positive connection" or a "positive connection" between at least two interconnected parts is understood here and below in particular to mean that the interconnected parts are held together at least in one direction by a direct interlocking of the contours of the parts themselves or by an indirect interlocking via an additional connecting part. The "blocking" of mutual movement in this direction is therefore due to the shape.

A "positive connection" or a "positive connection" between at least two interconnected parts is understood here and below in particular to mean that the interconnected parts are prevented from sliding against each other due to a frictional force acting between them. If a "connecting force" causing this frictional force (this means the force that presses the parts against each other, for example, a screw force or the force of gravity itself) is missing, the positive connection cannot be maintained and can therefore be released.

The knurled teeth of the annular collar have at least a certain geometric oversize relative to the receptacle, with a contact surface of the receptacle, against which the knurled teeth rest when joined, being comparatively smooth. This creates a knurled press connection between the inner and outer parts.

The knurled press fit offers advantages over a conventional press fit. Firstly, comparatively generous fit tolerances, for example, in the range of tenths of a millimeter, are permissible, so that essentially only hundredths of a millimeter are required, as with a conventional press fit. This reduces the component quality required to manufacture the scroll compressor, especially the bearing plate.

The knurled press fit allows the outer and inner parts of the bearing shield to be joined at room temperature. In particular, no additional heating or cooling of the joining partners is required. The tight fit of the inner part in the outer part can still be ensured across the entire temperature range of the scroll compressor. This results in low investment and assembly costs for the production of the scroll compressor and bearing shield.

Furthermore, the surface quality or surface cleanliness of the joining partners has only a minor influence on the joining forces and component tightness in a knurled press fit. The requirements for surface roughness and surface cleanliness of the mating surfaces can therefore be significantly reduced, which also reduces component and logistics costs.

"Axial" or an "axial direction" is understood here and below to mean, in particular, a direction parallel (coaxial) to the axis of rotation of the electric motor drive, i.e., parallel to the drive shaft. Accordingly, "radial" or a "radial direction" is understood here and below to mean, in particular, a direction oriented perpendicular (transverse) to the axis of rotation of the drive along a radius of the scroll compressor. "Tangential" or a "tangential direction" is understood here and below to mean, in particular, a direction along the circumference of the scroll compressor or the drive (circumferential direction, azimuthal direction), i.e., a direction perpendicular to the axial direction and the radial direction.

In an advantageous embodiment, a geometric oversize of the knurling teeth with respect to a diameter of the receptacle is less than or equal to two-thirds of a pitch of the knurling teeth. The geometric oversize U of the knurling teeth is thus determined by the formula $$U\le \frac{2}{3}t$$ given, where t is the division.

The pitch is the distance between two corresponding points on adjacent knurled teeth, measured along the circumference of the collar. This distance can be measured along the arc (radian) or along the chord (chord), depending on the specific application or standard.

The knurling teeth are thus dimensioned two-thirds of the pitch larger in the radial direction than the mounting. Additional removal of material at the knurling tooth tip simplifies, for example, the setting and maintenance of defined tolerances for the tip diameter, as well as the concentricity of the joined joints.

Even with an LF/DF ratio of 0.2, high torsion transmission capacities between the outer and inner parts are achievable. The abbreviation LF stands for the joining length, i.e., the axial engagement length of the inner part with the outer part, while DF stands for the joining diameter, i.e., the radial engagement length.

In a practical development, the outer part is made of a softer material than the inner part, so that the material of the outer part flows plastically into the knurled teeth when the inner part is pressed in, thereby creating the positive and/or frictional connection. The contact surface of the receptacle is thus at least partially reshaped when the annular collar is pressed in. A "soft" or "softer" material is understood to mean, in particular, a material with a lower hardness or a lower degree of hardness. In a practical development, the hardness difference between the material of the inner part and the material of the outer part is at least 3.1:1. In other words, the inner part is made of a material that is at least 3.1 times harder than the material of the outer part.

In a suitable embodiment, the outer part is made of an aluminum material and the inner part is made of a material with the same or at least a comparable thermal expansion coefficient as steel or cast iron of the second scroll.

In addition, the outer part is made of aluminum, and the inner part is made of a material with the same or at least a comparable thermal expansion coefficient as the steel or cast iron of the second scroll. In particular, the inner part is made of steel or cast iron. This also makes the material of the inner part harder than the material of the outer part, ensuring a reliable and stable knurled press connection.

In one conceivable embodiment, the receptacle is designed as a tangentially circumferential notch on an inner edge of the outer part. The inner part and the outer part each have a central recess for the drive shaft to pass through, with the annular collar enclosing the recess of the inner part, and the receptacle being incorporated as an annular notch in the area of the front edge of the recess of the outer part facing the inner part. This creates a particularly stable and reliable knurled press connection between the parts of the bearing plate.

In a particularly suitable design, the knurling teeth are axially parallel to the press-in direction, i.e., the axial direction. This is particularly advantageous for the axial joining process. Axial-parallel knurling refers in particular to axial-parallel knurls (knurls with axial-parallel grooves) of form RAA according to DIN 82.

For joining, the knurled annular collar is pressed axially into the holder. Geometric factors influence the type of joining process, from cutting to forming with combined intermediate steps, whereby the joining type in turn influences the transmission behavior of the connection. The geometric factors include, among other things, the chamfer angle of a threading chamfer at the beginning of the knurl. The threading chamfer serves in particular to facilitate the pressing in of the knurl. Small chamfer angles on the knurl cause a (forming) process during pressing in, with larger chamfer angles causing a cutting process. Preferably, the material of the outer part is formed so that it flows plastically into the knurl serration. Therefore, a suitable design of the knurl has a threading chamfer with a chamfer angle between 5° and 10°.

The bearing plate according to the invention is intended for, and is suitable and configured for, a scroll compressor described above. The multi-part, in particular two-part, bearing plate comprises an outer part and an inner part, which is bordered radially on the outside at least in some areas by the outer part. The outer part is equipped with a bearing seat for the shaft bearing for supporting the drive shaft, and the inner part has a number of axially projecting pins as part of the anti-rotation mechanism with the second scroll.

The inner part has a raised annular collar with knurled teeth. The inner part is pressed or can be pressed axially into a receptacle of the outer part by means of the knurled annular collar, either positively and/or non-positively. This creates a particularly suitable bearing shield.

The ring collar, for example, is designed with a knurled toothing with 253 teeth, a pitch of 1 mm, and a threading chamfer with a chamfer angle between 5° and 8°. Alternatively, the Ring collars, for example, are designed with a knurled toothing with 157 teeth, a pitch of 1.6 mm, and a threading chamfer with a chamfer angle between 5° and 8°.

• 1 in perspektivischer Seitenansicht einen Scrollverdichter,
• 2 in perspektivischer Darstellung ausschnittsweise ein Antrieb des Scrollverdichters,
• 3 in perspektivischer Darstellung ausschnittsweise einen Verdichterkopf des Scrollverdichters,
• 4 in perspektivischer Darstellung ein Lagerschild des Scrollverdichters,
• 5 in perspektivischer Darstellung ein Innenteil des Lagerschilds mit Blick auf eine Verdichterkopfseite,
• 6 in perspektivischer Darstellung das Innenteil mit Blick auf eine Antriebsseite,
• 7 in perspektivischer Darstellung ein Außenteil des Lagerschilds,
• 8 in perspektivischer Schnittansicht das Lagerschild,
• 9 in perspektivischer Schnittansicht ausschnittsweise einen Fügebereich des Lagerschilds, und
• 10 in Draufsicht ausschnittsweise den Fügebereich.

An embodiment of the invention is explained in more detail below with reference to a drawing. In the drawings:

• 1 in perspective side view a scroll compressor,
• 2 in perspective view, a section of a drive of the scroll compressor,
• 3 in perspective view, a section of a compressor head of the scroll compressor,
• 4 in perspective view a bearing plate of the scroll compressor,
• 5 in perspective view an inner part of the bearing plate with a view of a compressor head side,
• 6 in perspective view of the inner part with a view of a drive side,
• 7 in perspective view an outer part of the bearing shield,
• 8 in perspective sectional view of the bearing plate,
• 9 in perspective sectional view, a section of a joining area of the bearing shield, and
• 10 A section of the joining area in top view.

Corresponding parts and sizes are always provided with the same reference symbols in all figures.

The 1 The scroll compressor 2 shown is preferably designed as a refrigerant drive, preferably as a refrigerant compressor. The scroll compressor 2 is installed, for example, in a refrigerant circuit (not shown in detail) of an air conditioning system of a motor vehicle. The scroll compressor 2 is designed, in particular, as a _CO2 compressor, i.e., as a compressor for carbon dioxide as a refrigerant.

The scroll compressor 2, in particular an electric or electromotive one, has an electric (electromotive) drive 4 and a compressor head 6 coupled thereto. The scroll compressor 2 is also referred to below as compressor 2 for short.

The drive 4 on the one hand and the compressor head 6 on the other hand are, for example, modular in design, so that, for example, a drive 4 can be coupled to different compressor heads 6. A transition area formed between the modules 4 and 6 has a mechanical interface in the form of a bearing plate 8. The bearing plate 8 is also referred to below as the center plate of the scroll compressor 2. The compressor head 6 is connected to the drive 4 via the bearing plate 8. As shown, for example, in the illustration of the 1 As can be seen, the bearing plate 8 can, for example, form a housing or an outer wall of the scroll compressor 2 in sections.

The drive 4 has a pot-shaped drive housing with two housing sections 10a and 10b, which are separated from each other in a fluid-tight manner by a monolithically integrated housing partition (bulkhead) within the drive housing (not shown in detail). The drive housing is preferably manufactured as a die-cast part from an aluminum material.

The compressor head-side housing section is designed as a motor housing 10a for accommodating an electric motor 12 ( 2 ). The motor housing 10a is closed on the one hand by the (housing) intermediate wall and on the other hand by the bearing plate 8. The housing section opposite the intermediate wall is designed as an electronics housing 10b, in which a power electronics unit (motor electronics) is accommodated, not shown in detail, which controls and/or regulates the operation of the electric motor 12 - and thus of the scroll compressor 2.

The electronics housing 10b is closed with a housing cover (electronics cover) 14 toward a front side of the drive 4 facing away from the compressor head 6. When the housing cover 14 is open, the power electronics is mounted in an electronics compartment formed by the electronics housing 10b and is still easily accessible for maintenance or repair purposes when the housing cover 14 is removed.

The drive housing has a (suction gas) inlet 16 or suction port (inlet) for connection to the refrigerant circuit of the air conditioning system, approximately at the level of the electric motor 12. The refrigerant (suction gas), in particular _CO2 , flows into the drive housing, in particular into the motor housing 10a, via the inlet 16. From the motor housing 10a, the fluid flows through the bearing plate 8 to the compressor head 6. The refrigerant is then compressed by the compressor head 6 and exits the refrigerant circuit of the air conditioning system at a bottom-side (refrigerant) outlet 18 (outlet) of the compressor head 6.

The outlet 18 is formed on the bottom of a pot-shaped compressor housing 20 of the compressor head 6. When connected, the inlet 16 forms the low-pressure or suction side, and the outlet 18 forms the high-pressure or pump side, of the scroll compressor 2.

"Axial" or an "axial direction A" is understood here and below to mean, in particular, a direction parallel (coaxial) to the axis of rotation of the electric motor 12, i.e., along the longitudinal direction of the scroll compressor 2. Accordingly, "radial" or a "radial direction" is understood here and below to mean, in particular, a direction oriented perpendicular (transversely) to the axis of rotation of the electric motor 12 along a radius of the electric motor 12. "Tangential" or a "tangential direction" is understood here and below to mean, in particular, a direction along the circumference of the electric motor 12 (circumferential direction, azimuthal direction), i.e., a direction perpendicular to the axial direction and the radial direction.

The 2 shows a view of the A-side of the drive housing with the bearing plate 8 removed. The particularly brushless electric motor 12 comprises a rotor 24 which is non-rotatably coupled to a drive shaft (motor shaft) 22 and which is rotatably arranged within a wound stator 26. The motor shaft 22 is rotatably or rotatably mounted by means of two shaft bearings 28. One shaft bearing is arranged in a bearing seat which is formed on the housing base or on the intermediate wall of the drive housing. The other shaft bearing 28, which is in 2 can be seen is in a 7 and 8 visible bearing seat 30 of the bearing plate 8.

As in connection with 3 As can be seen comparatively clearly, the scroll compressor 2 or the compressor head 6 has a movable scroll (scroll part) 32 arranged in the compressor housing 20. This is coupled to the motor shaft 22 of the electric motor 12 by means of a counterweight (not shown in detail) as a swing link or eccentric via two joining pins or shaft journals 34, 36. The shaft journal 34 is designed as a so-called eccentric pin and the shaft journal 36 as a so-called limiter pin.

The scroll compressor 2 or the compressor head 6 also has a rigid, fixed scroll (scroll part) 38, which is fixed to the housing in the compressor housing 20. The two scrolls (scroll parts) 32, 38 mesh with each other via helical or spiral-shaped spiral walls (scroll walls, scroll spirals) not shown in detail, which protrude axially from a respective base plate 40, whereby only the base plate 40 of the scroll 32 is shown in the figures. The scroll 38 also has a circumferential boundary wall 42 forming the outer circumference. The scrolls 32, 38 are made, for example, of steel or cast iron.

In the assembled state, a bearing 44 is placed on a section of the balance weight. 3 The bearing 44 shown is seated in the assembled state in a bearing seat 46 formed on the rear of the base plate 40.

Arranged around the bearing seat 46 are six bead-like, circular recesses 48 of the base plate 40, into which, in the assembled state, an (anti-rotation pin) extension of the bearing plate 8 engages. The extensions and recesses 48 interact as pin-ring contacts during compressor operation. To reduce friction, a sliding ring 50 is inserted into each of the recesses 48. During compressor operation, the circular recess walls with the sliding rings 50 roll against the extensions, thereby converting the rotational movement of the drive shaft 22 into an eccentric, orbiting scrolling movement of the movable scroll 32 relative to the stationary scroll 38.

The bearing plate 8 with the extensions not shown in detail and the base plate 40 with the recesses 48 together form an anti-rotation mechanism of the scroll compressor 2, which preferably also includes the shaft journals 34, 36, the counterweight and the bearing 44.

The following is based on the 4 to 10 The structure of the bearing plate 8 is explained in more detail. The bearing plate 8 is designed as a two-part assembly with a first central plate 52 and a second central plate 54. The central plate 52 is designed as an approximately pot-shaped outer part and is also referred to as such below. The outer part radially surrounds the approximately annular central plate 54, which is also referred to as the inner part 54 below.

The 7 The outer part 52, shown individually, has a central recess 56 for the drive shaft 22 on its pot base, with the bearing seat 30 for the shaft bearing 28 being formed around the recess 56. On an end face facing the compressor head 6, the outer part 52 has an approximately gear-ring-shaped receptacle 58 for the inner part 54. At a bottom of the receptacle 58, six axial bores 60, for example threaded bores, arranged tangentially and distributed around the circumference, are introduced for fastening, in particular for screw fastening, the inner part 54.

On the radially inner side, the receptacle 58 has an axial offset. The offset is introduced as a circumferential, annular notch in the inner wall of the outer part 52. The notch forms a receptacle 62.

The outer part 52 is made, for example, of aluminum or an aluminum material, wherein an outer wall 64 of the outer part 52, for example, forms at least a portion of a housing section of the scroll compressor 2. In the assembled state, the outer part 52 is fixedly joined to the motor housing 10a on the one hand and to the compressor housing 20 on the other.

In the assembled state, the inner part 54 is a housing wall fixedly mounted in the outer part 52, which is arranged between the bearing seat 30 and the base plate 40. The annular inner part 54 has, for example, seven radially projecting screw tabs 65, which engage tangentially in the gear-ring-like receptacle 58 of the outer part 52 and are arranged axially aligned with the bores 60. In the assembled or joined state, the screw tabs 65 and the bores 60 are each penetrated by a fastening screw.

The inner part 54 is preferably designed as a one-piece, i.e., single-piece or monolithic, component. The central ring opening of the inner part 54 has six radially inwardly projecting and tangentially evenly distributed retaining tabs 66, each retaining tab 66 having an axial through-opening (not further identified by reference numerals) into which the axially projecting extensions (pins) for the pin-ring anti-rotation mechanism can be pressed or are pressed. The extensions can also be integrally formed onto the retaining tabs 66, for example, by cold forming, in particular by deep drawing.

In the assembled state, the end faces of the inner part 54 and the base plate 40 preferably lie substantially directly against one another. In other words, preferably no additional wear plate is provided between the inner part 54 and the base plate 40. The inner part 54 preferably acts as a sliding element for the base plate 40.

Preferably, the inner part 54 is made of the same material as the scroll 32. The inner part 54 is made, for example, of cast iron or steel, in particular of a cold-rolled steel sheet.

The inner part 54 has an axially upstanding annular collar 68 on a rear side facing away from the base plate 40, which encloses the central annular opening of the inner part 54. The annular collar 68 is provided radially on the outside with a circumferential knurling or knurling toothing 70. The knurling toothing 70 is designed as a knurling of form RAA according to DIN 82, axially parallel to the axial direction A, so that the grooves of the knurling run parallel to the axial direction.

As particularly in the 8 to 10 As can be seen, the annular collar 68 is pressed axially, in particular radially and tangentially, in a form-fitting and force-fitting manner into the receptacle 62 of the outer part 52. A knurled press connection is formed between the essentially smooth inner wall of the receptacle 62 and the knurled toothing 70.

The knurled toothing 70 has a pitch not specified in more detail, wherein the knurled annular collar 68 has a geometric oversize compared to the inner diameter of the receptacle 62, which is less than or equal to two-thirds of the pitch.

The hardness difference between the material of the inner part 54 and the material of the outer part 52 is at least 3.1:1. Furthermore, the edge collar has a threading chamfer, not further identified by reference numerals, with a chamfer angle between 5° and 10°, in particular between 5° and 8°.

When the inner part 54 is pressed axially into the outer part 52 or the knurled annular collar 68 into the receptacle 62, the difference in hardness of the materials and the small chamfer angle at least partially cause a deformation of the receptacle 62, which flows plastically into the knurled toothing 70 and thus realizes the positive and/or non-positive connection, in particular in the tangential and radial directions ( 10 ).

The ring collar, for example, is designed with a knurled toothing with 253 teeth, a pitch of 1 mm, and a threading bevel with a bevel angle between 5° and 8°. Alternatively, the ring collar is designed with a knurled toothing with 157 teeth, a pitch of 1.6 mm, and a threading bevel with a bevel angle between 5° and 8°.

The claimed invention is not limited to the embodiments described above. Rather, other variants of the invention can also be derived therefrom by a person skilled in the art within the scope of the disclosed claims, without departing from the subject matter of the claimed invention. In particular, all individual features described in connection with the various embodiments are also applicable to other way without departing from the subject matter of the claimed invention.

List of reference symbols

2

Scroll compressor

4

drive

6

Compressor head

8

bearing plate

10a

Housing part area, engine housing

10b

Housing part area

12

electric motor

14

Housing cover

16

inlet

18

Outlet

20

Compressor housing

22

drive shaft

24

rotor

26

stator

28

Shaft bearings

30

warehouse location

32

Scroll

34

Shaft journal, eccentric pin

36

Shaft journal, limiter pin

38

Scroll

40

Base plate

42

boundary wall

44

warehouse

46

warehouse location

48

Deepening

50

sliding ring

52

Central plate, outer part

54

Central plate, inner part

56

recess

58

Recording

60

drilling

62

Recording

64

exterior wall

65

screw tabs

66

Retaining tabs

68

Ring collar

70

Knurled serration

A

axial direction

QUOTES CONTAINED IN THE DESCRIPTION

This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10 2012 104 045 A1 [0003]
• DE 10 2024 201 453.2 [0010]

Claims (9)

Scroll compressor (2) for a refrigerant of a vehicle air conditioning system, in particular for carbon dioxide, comprising - a first scroll (38) with a base plate and a spiral wall, - a second scroll (32) movable relative to the first scroll (38) and having a base plate (40) and a spiral wall which engages in the spiral wall of the first scroll (38) and forms compression chambers therewith, - an electric motor drive (4) which is coupled to the second scroll (32) by means of a drive shaft (22) for power transmission, and - a bearing plate (8) which is arranged between the drive (4) and the second scroll (32) and which is formed in two parts from an outer part (52) and an inner part (54) which is bordered radially on the outside at least in regions by the outer part (52), - wherein the outer part (52) carries a shaft bearing (28) for the drive shaft (22), - wherein the inner part (54) has an anti-rotation mechanism is coupled to the second scroll (32), - wherein the inner part (54) has an upstanding annular collar (68) with a knurled toothing (70), and - wherein the inner part (54) is pressed axially into a receptacle (62) of the outer part (52) by means of the knurled annular collar (68) in a form-fitting and/or force-fitting manner. Scroll compressor (2) after Claim 1 , characterized in that a geometric oversize of the knurled toothing (70) is less than or equal to two-thirds of a pitch of the knurled toothing (70). Scroll compressor (2) after Claim 1 or 2 , characterized in that the outer part (52) is made of a softer material than the inner part (54), so that the material of the outer part (52) flows plastically into the knurled toothing (70) when the inner part (54) is pressed in. Scroll compressor (2) after Claim 3 , characterized in that a hardness difference between the material of the inner part (54) and the material of the outer part (52) is at least 3.1:1. Scroll compressor (2) according to one of the Claims 1 until 4 , characterized in that the outer part (52) is made of an aluminum material and the inner part (54) is made of a steel or cast iron. Scroll compressor (2) according to one of the Claims 1 until 5 , characterized in that the receptacle (62) is designed as a tangentially circumferential notch on an inner edge of the outer part (52). Scroll compressor (2) according to one of the Claims 1 until 6 , characterized in that the knurled teeth (7) are designed axially parallel to the axial pressing direction. Scroll compressor (2) according to one of the Claims 1 until 7 , characterized in that the knurled toothing (70) has a threading chamfer with a chamfer angle between 5° and 10°. End shield (8) for a scroll compressor (2) according to one of the Claims 1 until 8 , comprising an outer part (52) and an inner part (54) which is bordered radially on the outside at least in regions by the outer part (52), - wherein the outer part (52) has a bearing seat (30) for the shaft bearing (28), - wherein the inner part (54) has a number of axially upstanding pins as part of the anti-rotation mechanism, - wherein the inner part (54) has an upstanding annular collar (68) with knurled teeth (70), and - wherein the inner part (54) is or can be pressed axially into a receptacle (62) of the outer part (52) by means of the knurled annular collar (68) in a form-fitting and/or force-fitting manner.