Ball bearing

Abstract

The invention relates to a ball bearing for a scroll of a scroll compressor, having an outer ring (1), an inner ring (2) and a plurality of balls (3) arranged therebetween, characterized in that the balls (3) are held in and guided in a ball bearing cage (4), wherein the ball bearing cage (4) is formed as an outer-guided plastic cage with a reinforcing structural element (6) made of metal, thus as a hybrid cage.

Description

Technical Field

[0001] This invention relates to ball bearings, particularly ball bearings for the moving scroll components of scroll compressors. The ball bearing has a ball bearing cage, which is constructed as an externally guided plastic cage. Background Technology

[0002] Ball bearings with cages sometimes need to meet the highest requirements in terms of tolerances, smooth operation, roundness, and surface quality. Ball bearing cages are used in a variety of applications, such as supporting the moving scroll components of scroll compressors.

[0003] In the prior art, ball bearing cages are made of plastics such as polyamide-imide or polyetheretherketone, or of phenolic resin with a fine mesh fabric. Alternatively, ball bearing cages are also made of steel or non-ferrous metals.

[0004] In addition to ball bearing cages with external and internal guides, riveted ball bearing cages or ball bearing cages with various internal and external profiles are also known.

[0005] As an example, EP 2 932 118B1 teaches a two-piece ball bearing cage having multiple forked portions forming retaining claws.

[0006] DE 35 10 467A1 discloses a ball bearing cage for a radial ball bearing, the ball bearing cage being constructed of an annular body made of an elastic material, the annular body having a recess for receiving balls in a snap-fit ​​manner and a guide pin for guiding the balls into the recess. A retaining ring on the guide pin restricts deformation of the annular body. This prevents the annular body from being ejected during bearing operation due to the contact forces generated between the balls and the cage.

[0007] DE 199 51 387A1 discloses a ball bearing cage made of an elastically deformable plastic material, the ball bearing cage having a spherical ball seating surface arranged in a recess. The bearing balls are seated in the recess, which adapts to changes in length by increasing the recess clearance.

[0008] In certain applications, there are specific requirements for ball bearings and ball bearing cages. Using ball bearings in the moving scroll components of a scroll compressor is one such application where there are special requirements for the ball bearings and ball bearing cages used.

[0009] Due to the rotational motion of the scroll component within the scroll compressor, the ball bearings are additionally subjected to centrifugal force. This force depends on the mass of the scroll component, its rotational radius, and its rotational speed.

[0010] In template applications of scroll compressors in the refrigerant circuits of motor vehicles, it is necessary to increase the mass flow rate of the refrigerant in the circuit to achieve adequate cooling of various components in the vehicle and the passenger compartment itself. This increased mass flow rate of the refrigerant in the circuit leads to higher loads and speeds on the scroll compressor used. Both factors also increase the centrifugal force on the ball bearings.

[0011] The ball-guided metal cages designed according to existing technology exceed their load limits, and experience shows that they fail relatively frequently.

[0012] In ball bearings, externally guided plastic cages are generally more suitable than ball-guided metal cages, but they present strength issues in the thinnest area of ​​the ball bearing cage. This thinnest area, also known as the bridging section, is where the balls need to pass. Constrained by the inner and outer rings of the ball bearing, this space is not large enough to form a properly robust plastic cage. Summary of the Invention

[0013] Technical issues

[0014] The object of this invention is to provide a ball bearing capable of withstanding the increased mechanical demands induced by centrifugal forces within the ball bearing. Therefore, this object is to improve the service life of the ball bearing through extensive material reinforcement without altering its dimensions.

[0015] Solution to the problem

[0016] This objective is achieved by means of the subject matter of claim 1 of the patent. Other improvements are described in detail in the dependent patent claims.

[0017] More specifically, the object of the present invention is achieved by a ball bearing for a scroll component of a scroll compressor, the ball bearing having an outer ring, an inner ring, and a plurality of balls disposed therebetween, wherein these balls are held in and guided within a ball bearing cage. The ball bearing cage is formed as an externally guided plastic cage with a reinforcing structure made of metal, thus serving as a hybrid cage. The term "hybrid cage" should be understood to refer to a ball bearing cage made of different materials, which are bonded together to form a hybrid cage.

[0018] The ball bearing cage is a snap-fit ​​type single-sided cage, which laterally receives the balls in a recess of the plastic cage on one side of the ball bearing. During assembly, the balls are received by the plastic cage in a snap-fit ​​action, and the suspension area of ​​the plastic cage surrounds the balls on the opposite second side of the ball bearing. A metal reinforcing structure is provided in the plastic cage, which gives the ball bearing cage its mechanical strength and resistance.

[0019] For the purposes of this invention, the reinforcing structural member should be understood to refer to an annular element made of metal that interacts with and mechanically reinforces the plastic retainer due to the connection between the metal and the plastic retainer. In particular, this enhances the mechanical load-bearing capacity related to the applied centrifugal force.

[0020] Therefore, the ball bearing cage is formed of a plastic cage having an area for receiving the balls, which is limited by a suspension portion facing the second side.

[0021] Advantageously, the reinforcing structural member is housed inside the plastic retainer. Therefore, the plastic material completely accommodates and surrounds the reinforcing structural member.

[0022] Alternatively, the reinforcing structure is at least partially disposed on the outside of the plastic cage and mechanically and securely connected to the ball bearing cage, such that the reinforcement of the entire ball bearing cage is achieved by the external reinforcing structure.

[0023] Preferably, the reinforcing structural member is designed as an insert in the ball bearing cage, wherein the web area of ​​the plastic cage is subjected to special mechanical reinforcement.

[0024] The web region of the ball bearing cage is the area where the material thickness is most reduced by the concave portion of the ball, i.e., the thinnest region towards the side.

[0025] Particularly advantageously, the reinforcing structural member is formed from a circumferentially shaped annular member or wire. Therefore, the annular member or wire is disposed inside or outside the ball bearing cage as a reinforcing structural member. When disposed inside or partially outside the ball bearing cage, the annular member or wire is formed by overmolding or partially overmolding the reinforcing structural member with plastic material and is securely connected to the plastic material of the ball bearing cage.

[0026] Advantageously, the reinforcing structural member is formed as a circumferentially shaped annular member with an I-shaped profile. The I-shaped profile is designed in the cross-section between the inner and outer rings of the ball bearing and is arranged in the radial direction. The I-shaped profile member forms a flattened annular member, wherein the width in the axial direction and the height in the radial direction of the annular member are aligned with respect to the ball bearing.

[0027] Alternatively, the reinforcing structural member is formed as a circumferentially shaped ring with an H-shaped profile, wherein one lateral portion of the H-shaped profile is located inside the plastic material of the ball bearing cage, and the other lateral portion is located outside the plastic material of the ball bearing cage. The lateral portions of the H-shaped profile are connected by a central web, which forms a mechanical connection between the lateral portions, and thus improves the effect of the profile by means of the overmolded and unovermolded areas.

[0028] Alternatively, the reinforcing structural member is formed as a circumferential ring with an X-shaped profile, wherein one side is successively molded with webs of two plastic materials arranged at an angle to each other, and the two sides or the entire X-shaped profile member is embedded in the plastic material of the ball bearing cage.

[0029] An advantageous alternative embodiment of the invention is that the reinforcing structural member is formed as a ring-shaped member with an L-shaped profile and a circular shape.

[0030] More preferably, the reinforcing structural member is designed as a circumferentially shaped ring with an O-shaped profile. The O-shaped profile member is also called an O-ring. These profile members can be formed as solid profile members or hollow profile members.

[0031] Furthermore, various cross-sections can be achieved for reinforcing structural components. Specifically, these shapes can be adapted to specific applications.

[0032] The plastic ball bearing cage is preferably made of polyamide-imide, polyetheretherketone, or phenolic resin with a fine mesh cotton fabric.

[0033] To achieve the required strength within the limited space available for ball bearing cages, a hybrid solution was developed based on this concept. Metal reinforcements in the bridging area around the balls absorb stress. These reinforcements can be located inside or outside the main plastic body of the ball bearing cage, as long as a strong connection between the different materials is ensured. Suitable reinforcements include inserts in the web area, circumferentially shaped rings or wires, I-shaped, L-shaped, X-shaped, or O-shaped profiles, and the web itself.

[0034] The advantageous mechanical properties resulting from hybrid ball bearing cages should be emphasized as particularly beneficial. They combine the elasticity of plastic materials with the stability of metals. Because centrifugal forces can be better absorbed, the reliability of ball bearings can be significantly improved. This allows for the delivery of larger mass flow rates in scroll compressor applications used in refrigerant circuits, offering process-related advantages.

[0035] Another advantage is that by using a ball bearing cage with reinforcing structural members made of metal, the installation space for the ball bearing can be reduced. The reinforcement of the ball bearing cage achieved through the reinforcing structural members results in increased strength, which eliminates the need for typically protruding material reinforcements and thus allows for a narrower overall size of the ball bearing. Attached Figure Description

[0036] Further details, features, and advantages of embodiments of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. In the drawings:

[0037] Figure 1 A perspective view and cross-section of a ball bearing with a hybrid ball bearing cage and an H-shaped profile are shown.

[0038] Figure 2a A detailed cross-section of a ball bearing with a double O-shaped profile as a reinforcing structural element is shown.

[0039] Figure 2b The diagram shows a reinforcing structural member that serves as an X-shaped profile.

[0040] Figure 2c This shows a reinforcing structural member that serves as an I-shaped profile. Detailed Implementation

[0041] Figure 1 A three-dimensional cross-sectional view of a ball bearing is shown. The ball bearing consists of basic elements of an outer ring (1) and an inner ring (2) and balls (3) disposed between them. The balls (3) are held in their positions by a ball bearing cage (4), and additionally, a suspension part (5) for fixing the components to each other is shown, and a reinforcing structure (6) as part of the ball bearing cage (4) is shown.

[0042] According to Figure 1 In this embodiment, the reinforcing structural member (6) has an H-shaped profile. The H-shaped profile has two parallel lateral sides or legs connected to each other by a central web. The shape of the letter H is shown in cross-section and is positioned accordingly between the outer ring (1) and the inner ring (2). One lateral side is incorporated into and fully received by the plastic matrix of the ball bearing cage (4), while the other lateral side of the H-shaped profile is constructed on the outside of the plastic cage, which, according to Figure 1The diagram shows a wider annular portion. Due to the thinner material, the ball bearing cage (4) with its plastic retainer component is more susceptible to mechanical strain in the area where the balls are positioned. The reinforcing structure (6) stabilizes these areas subjected to specific mechanical strain by forming a hybrid ball bearing cage. Therefore, in the scroll compressor used, it is possible to achieve a higher speed with a correspondingly higher centrifugal force and thus a higher mass flow rate without changing the dimensions of the ball bearing or the ball bearing cage (4).

[0043] According to Figure 1 In an exemplary embodiment, a single-sided ball bearing cage (4) is shown. A cross-section through the upper portion of the ball bearing shows the area outside the ball (3). The plastic cage of the ball bearing cage (4) is shaded in opposite directions to the cross-section through the reinforcing member (6). The area of ​​the suspension portion (5) of the plastic cage encloses the ball (3) toward the open right side of the ball bearing and accordingly holds and guides it.

[0044] The lower section of the ball bearing shows a cross-section in the web region of the ball bearing cage (4). The balls (3) are shown in full cross-section. In this location, the web region has the minimum material thickness of the plastic material. In these regions, the reinforcing structural members (6) made of metal result in a significant increase in the strength and load capacity of the ball bearing cage (4), and thus an improvement in the overall ball bearing.

[0045] Figure 2a , Figure 2b , Figure 2c A portion of a ball bearing is shown, with particular focus on the design of the reinforcing structure (6) inside the ball bearing cage (4).

[0046] Figure 2a , Figure 2b and Figure 2c All embodiments show the basic components of a ball bearing having an outer ring (1), an inner ring (2), and balls (3) disposed between them. The difference between the various embodiments lies in the design of the reinforcing structural member (6).

[0047] Figure 2a Two O-ring profiles are shown, which are solid profiles in the form of wire loops and are joined in a ring-like manner in the ball bearing cage (4). The O-rings of the reinforcing structure (6) are completely surrounded by the plastic material of the ball bearing cage (4).

[0048] Figure 2bThe special design features of the reinforcing structure (6) in the form of an X-shaped profile inside the ball bearing cage (4) are shown. In cross-section, the X-shaped profile is positioned between the outer ring (1) and the inner ring (2) and is completely surrounded by the plastic matrix of the plastic cage. This design provides exceptional torsional stiffness.

[0049] Figure 2c An I-shaped profile is shown as a reinforcing structural member (6), which is completely received by the plastic matrix of the plastic ball bearing cage (4). The I-shaped profile shown is also completely surrounded by the plastic matrix of the plastic cage.

[0050] List of reference numerals

[0051] 1 Outer ring

[0052] 2 Inner Circle

[0053] 3 ball bearings

[0054] 4 ball bearing cage

[0055] 5 Suspension Part

[0056] 6 Reinforced structural components

Claims

1. A ball bearing for a scroll of a scroll compressor, the ball bearing having an outer ring (1), an inner ring (2) and a plurality of balls (3) disposed between the outer ring (1) and the inner ring (2), characterized in that, The ball (3) is held in and guided in the ball bearing cage (4), wherein the ball bearing cage (4) is formed as a plastic cage with an external guide of a reinforcing member (6) made of metal, thus serving as a hybrid cage, the reinforcing member (6) being formed as a circumferentially shaped annular member with an H-shaped profile and having two parallel lateral sides connected to each other by a central web, one lateral side being located inside the plastic cage and the other lateral side being located outside the plastic cage.

2. The ball bearing of claim 1, wherein, The reinforcing member (6) is designed as an insert in the plastic cage of the ball bearing cage (4) for reinforcing the web area.

3. The ball bearing according to claim 1 or 2, characterized in that, The ball bearing cage (4) is formed of polyamide-imide.

4. The ball bearing according to claim 1 or 2, characterized in that, The ball bearing cage (4) is formed of polyetheretherketone.

5. The ball bearing according to claim 1 or 2, characterized in that, The ball bearing cage (4) is formed of phenolic resin with a fine mesh cotton fabric.

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