Tilt pad bearings

Abstract

The invention relates to a tilting pad bearing (10) having tilting pads (1, 2, 3) which can be tiltably positioned and held in a housing body by means of a frame-like spring device (8) so that, during operation of the tilting pad bearing (10), a converging bearing gap is generated between the tilting pads (1, 2, 3) and a rotor body (4) which is rotatably mounted about an axis of rotation. In order to improve the tilting pad bearing (10) functionally and / or in terms of production technology, the tilting pad bearing (10) is characterized in that rolling elements (6, 7) are provided which are arranged between the housing body (5) and the tilting pads (1, 2, 3).

Description

Technical Field

[0001] The invention relates to a tilting pad bearing having tilting pads which are tiltably positioned and held in a housing body by means of a frame-like spring device so that, during operation of the tilting pad bearing, a converging bearing gap is generated between the tilting pads and a rotor body which is rotatably mounted about an axis of rotation. Background Art

[0002] German laid-open patent application DE 10 2016 216 395 A1 discloses a tilting pad bearing comprising a sleeve, a plurality of tilting pads, and a frame in which the tilting pads are accommodated, wherein a spring element is provided between the inner side of the sleeve and the associated tilting pad, wherein the spring element is connected to the frame or is arranged as a separate component between the inner side of the sleeve and the frame. The frame has at least one retaining section for retaining the associated tilting pad in the frame, wherein each tilting pad is retained in the frame by the at least one retaining section in such a way that the tilting pad has play in the radial direction and preferably also in the circumferential direction, in order to allow the tilting pad to tilt in the circumferential direction. Summary of the Invention

[0003] The object of the present invention is to improve a tilting pad bearing in terms of function and / or production technology, wherein the tilting pad bearing has tilting pads which are positioned and held in a housing body by means of a frame-like spring device so as to be tiltable, so that during operation of the tilting pad bearing, a converging bearing gap is generated between the tilting pads and a rotor body which is rotatably mounted about an axis of rotation.

[0004] This problem is solved by rolling elements in a tilting pad bearing with tilting pads. The tilting pads are tiltably positioned and retained in a housing body by means of a frame-like spring arrangement. This creates a narrow bearing gap during operation of the tilting pad bearing between the tilting pads and a rotor body rotatably mounted about an axis of rotation. The rotor body is arranged between the housing body and the tilting pads. The rotor body is, for example, a shaft segment. In many technical fields, rapidly rotating shafts must be supported. For example, such shafts are required in turbocompressors, which are used, in particular, to compress air for supercharged internal combustion engines or fuel cell systems. Other components, such as turbine wheels, compressor wheels, or magnets for electric drives, are typically mounted on, within, or at the shaft. These components also rotate at very high speeds. The shaft can be constructed in one or more pieces. It is preferably supported by multiple bearing units, such as two radial bearings and one axial bearing. During operation, when forces and moments act on the shaft, the bearing units must be able to rotate with minimal losses. Gas-lubricated bearings are advantageously used for the support because they have very low friction at very high rotational speeds and thus only minimal bearing losses. Furthermore, oil or grease lubrication is unnecessary in gas-lubricated bearings. This is particularly advantageous in fuel cell applications, because the compressor air supplied here must be oil-free in order not to damage the fuel cell stack. The tilting pad bearing advantageously comprises at least three tilting pads. Particularly preferably, the tilting pad bearing comprises exactly three tilting pads. The tilting pad bearing claimed for protection is preferably a radial bearing. The tilting pads are positioned and held relative to one another by a spring arrangement in such a way that they can perform the tilting movement that occurs during operation of the tilting pad bearing. The tilting pads can tilt about a so-called fulcrum or pivot or tilting axis. Rolling bodies are advantageously used to enable the tilting movement of the tilting pads. The tilting pads are supported radially in a point-like or linear manner in the radial bearing by the rolling bodies. The rolling bodies are particularly advantageously standardized components for rolling bearings, such as balls, rollers, or needle rollers. These standardized rolling elements are commercially available at low cost.

[0005] A preferred embodiment of a tilting pad bearing is characterized in that the rolling elements are designed as rollers. The rollers preferably have a substantially right cylindrical configuration, with their cylinder axes arranged parallel to the axis of rotation of the rotor body. Each tilting pad is advantageously assigned at least one rolling element. The rollers enable a defined tilting movement of the tilting pad to be easily achieved during operation of the tilting pad bearing.

[0006] Another preferred embodiment of the tilting pad bearing is characterized in that the rolling elements are embodied as balls. Each tilting pad can be equipped with a plurality of balls. These balls are then advantageously arranged parallel to the axis of rotation of the rotor body. According to a preferred embodiment, each tilting pad is equipped with exactly one rolling element embodied as a ball. This also offers the advantage that the associated tilting pad can be tilted not only about an axis parallel to the axis of rotation of the rotor body (also referred to as the shaft axis), but also about an axis perpendicular thereto. This allows for compensation of undesirable, but in practice difficult to avoid, angular misalignments of the rotor body or the shaft or the housing bore of the housing body. In this embodiment, the tilting pad can advantageously be oriented relative to the axis of rotation or the shaft axis.

[0007] Another preferred embodiment of the tilting pad bearing is characterized by a cage that serves to hold the rolling elements in position between the housing body and the tilting pad. According to one embodiment, the cage serves solely to hold the rolling elements in position between the housing body and the tilting pad. This offers the advantage that the cage can be implemented relatively simply and can therefore be manufactured cost-effectively. The cage enables pre-assembly of the rolling elements. The cage comprises, for example, at least one annular body. This annular body only needs to have one through-hole for each rolling element in order to receive the rolling element. According to an embodiment, the spring device is also equipped with a corresponding through-hole. The through-hole serves, on the one hand, to position the rolling elements. Furthermore, the through-hole enables the rolling elements to be brought into contact with the rotor body and with the housing body. In another embodiment, the spring device can also be used solely to position the rolling elements. The cage can then be omitted.

[0008] Another preferred embodiment of a tilting pad bearing is characterized in that the cage has a through-hole in which the rolling elements are received with clearance, so that outside the through-hole, the rolling elements are in rolling contact not only with the housing body but also with the tilting pads. Depending on the embodiment, the spring device, or at least a portion of the spring device, is still arranged radially between the cage and the rotor body or between the cage and the housing body. The spring device is then advantageously provided with a through-hole at the corresponding position, which is coaxial with the corresponding through-hole in the cage. The cage allows the rolling elements to be stably held in a desired position between the rotor body and the housing body in a simple manner.

[0009] Another preferred embodiment of the tilting pad bearing is characterized in that the cage comprises at least one simple annular body. The annular body is configured, for example, as a circular ring with a rectangular annular cross-section. This simplifies the manufacture of the annular body. The configuration of the through-holes in the annular body advantageously substantially matches the configuration of the rolling elements. The cage can also comprise two annular bodies. Depending on the embodiment, the annular bodies can also be connected to each other via webs.

[0010] Another preferred embodiment of the tilting pad bearing is characterized in that each tilting pad is assigned a spring element to tiltably position and retain the associated tilting pad in the housing body. In this embodiment, the spring device advantageously includes exactly one spring element per tilting pad. This simplifies the manufacture of the spring device. The spring elements advantageously each include a retaining section at their circumferentially opposite ends, by means of which each spring element engages with the associated tilting pad. According to another embodiment or feature, a retaining cage, whether in a one-piece embodiment having only one annular body or in a two-piece embodiment having two annular bodies, advantageously serves to position the spring elements at least in the axial direction within the tilting pad bearing.

[0011] Another preferred embodiment of a tilting pad bearing is characterized in that the spring element engages the associated tilting pad at its circumferentially opposite ends. For this purpose, the spring element can have exactly one retaining section at each of its circumferentially opposite ends. However, the spring element can also be provided with multiple retaining sections at its opposite ends. This provides greater design freedom in the implementation of the spring device and / or cage.

[0012] Another preferred embodiment of the tilting pad bearing is characterized in that the spring element includes at least one spring leaf that is preloaded inwardly against the associated tilting pad. This spring leaf advantageously extends through a through-hole provided for this purpose in the retaining frame. Alternatively or additionally, the spring element may include an additional spring leaf that is preloaded against the housing body. The spring element with the spring leaf secures and positions the tilting pad and advantageously preloads the tilting pad by means of the spring leaf, so that when the rotor body is not rotating, the tilting pad is pressed against the rotor body on one side.

[0013] The invention also relates to a cage, a tilting pad, a spring element, a housing body and / or rolling elements for the tilting pad bearing. The aforementioned parts can be purchased separately. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Further advantages, features and details of the present invention are apparent from the following description of the drawings. In the description, various exemplary embodiments are explained in detail with reference to the drawings.

[0015] Figure 1 : A perspective view of a tilting pad bearing having three tilting pads, each of which is equipped with two spherical rolling elements;

[0016] Figure 2 : Similar to Figure 1 , wherein each tilting pad is equipped with a spherical rolling element;

[0017] Figure 3 : Similar to Figure 2, wherein each tilting pad is provided with a roller-shaped rolling element;

[0018] Figure 4 : Similar to Figure 3 1 and 2. An illustration of a housing with a cage, wherein the cage comprises only one annular body.

[0019] Figure 5 : Figure 4 A tilting pad bearing having a housing body shown in half cutaway; and

[0020] Figure 6 : A perspective view of a sheet metal strip which can be advantageously used to produce Figure 5 The rolling element cage shown is for a tilting pad bearing. Specific embodiments

[0021] exist Figures 1 to 5 The tilting pad bearing 10 is shown schematically and in a perspective view in different embodiments. Figures 1 to 5 The same reference numerals are used to identify the same or similar parts. First, the common features of the various embodiments are discussed. Then, the differences between the various embodiments are explained.

[0022] The tilting pad bearing 10 is designed as a radial bearing having three tilting pads 1, 2, 3. The rotor body 4 is mounted radially rotatably about the axis of rotation in the tilting pads 1, 2, 3. The rotor body 4 is, for example, a shaft or a shaft segment having a shaft.

[0023] The tilting pads 1, 2, 3 can be tilted by means of rolling bodies 6, 7, 20, 24, 44 about a support point or tilting axis or support point axis. Figure 1 In FIG, each tilting pad 1 to 3 is provided with two rolling bodies 6, 7, which are designed as balls. Figures 2 to 5 In the embodiment, each tilting pad 1 to 3 is assigned exactly one rolling element 20; 24; 44. The rolling element 20 is implemented as a ball. The rolling elements 24; 44 are implemented as rollers.

[0024] The tilting pads 1 to 3 are positioned and held relative to each other and relative to the rotor body 4 by means of spring means 8. Figure 5 The spring device 8 is combined with the retaining frame 9.

[0025] exist Figure 1 In FIG, the retainer 9 comprises two annular bodies 11, 12. The spring device 8 comprises three spring elements 13, 14, 15. Each spring element 13, 14, 15 is assigned exactly one tilting pad 1, 2, 3.

[0026] The spring elements 13, 14, 15 are arranged axially between the two annular bodies 11, 12. The spring elements 13, 14, 15 and the tilting pads 1, 2, 3 and the annular bodies 11, 12 are each designed identically. Furthermore, the above-mentioned single-part structure is simple in design and can therefore be manufactured cost-effectively.

[0027] The spring element 13 comprises a retaining section 16, 17 at its circumferentially opposite ends. The retaining sections 16, 17 allow the spring element 13 to engage with the associated tilting pad 1. In the axial direction, the spring element 13 is positioned between the two annular bodies 11, 12. In addition, the spring element 13 has a spring leaf 18 which bears radially outward against the housing body ( Figure 5 5) Pre-tighten.

[0028] The annular bodies 11, 12 each comprise a through-hole 19 for receiving the rolling bodies 6, 7, which are designed as balls. The balls 6 are received with play in the through-hole 19, which is designed as an elongated hole, for example.

[0029] The tilting pads 1 to 3 shown have an inner diameter and an outer diameter. Unlike what is shown, the tilting pads 1 to 3 can also take almost any shape. If the tilting pads 1 to 3 are designed as ring segments, for example, they can be produced cost-effectively by dividing a ring.

[0030] exist Figure 2 In the embodiment, each tilting pad 1 to 3 is provided with a rolling body 20 designed as a ball. The spring element 23 associated with the tilting pad 1 comprises a through hole 22 in which the ball 20 is received with clearance. The through hole 22 is designed to be circular. In addition, the spring element 23 has a spring leaf 21. Figure 2 In the embodiment, the spring leaf is pre-tightened radially inwardly against the rotor body 4 .

[0031] The cage 9 comprises two annular bodies 31 and 32. Figure 2 and Figure 3 In the embodiment shown, the annular body serves only to position the spring element 23; 27 in the axial direction. Figure 1 Compared to the ring bodies 11 and 12 in FIG. 1 , the ring bodies 31 and 32 are not provided with through holes for rolling elements ( Figure 1 19).

[0032] exist Figure 3 In FIG. 1 , a rolling element 24 designed as a roller is arranged in a through-hole 26 of a spring element 27 which is associated with the tilting pad 1 . Figure 2 In the embodiment shown, the spring blades 25 are prestressed radially inwardly against the rotor body 4. The arrangement of the spring blades 25 near the rolling elements 24 also offers the advantage that the rolling elements 24 are advantageously used for the orientation or positioning of the spring device 8 and the cage 9.

[0033] exist Figure 4 and Figure 5 In the embodiment shown, the cage 9 comprises only one annular body 45, which is arranged centrally in the axial direction with respect to the tilting pad bearing 10. In contrast to the previous embodiments, the spring element 43 is provided with two retaining sections 41, 42 at each circumferential end. By means of the retaining sections 41, 42, the spring element 43 is Figure 1 The tilting pad 1 engages on the circumferential end visible in FIG. The retaining sections 41 , 42 are arranged axially adjacent to the annular body 45 arranged between them.

[0034] Figure 5 Show Figure 4 A perspective view of the tilting pad bearing 10 with the housing body 5 shown in half section. The housing body 5 comprises a housing bore 48 in which the tilting pad bearing 10 is received. The positioning tabs 46 are angled radially outward from the spring element 43 .

[0035] The positioning lug 46 engages in a through-hole 47 provided for this purpose in the housing body 5. Adjacent to the positioning lug 46, the spring element 43 comprises a through-hole (not shown) for the rolling element 44. A corresponding through-hole is provided in an annular body 45 for the rolling element 44, which is arranged radially between the tilting pad 1 and the spring element 43.

[0036] The positioning lugs 46 serve to provide a rotational fixation in the housing bore 48 of the housing body 5. Unlike what is shown, the positioning lugs 46 can also be embedded in corresponding grooves or recesses in the housing body 5.

[0037] exist Figure 6 The annular body ( Figure 5 How can 45) be produced in a simple and cost-effective manner from a sheet metal strip 57? The sheet metal strip 57 comprises through-holes 51 to 53 and 54 to 56, which can be produced in the sheet metal strip 57 by stamping, for example. The through-holes 51 to 53 are each used to receive a rolling element ( Figure 5 44).

[0038] Through-holes 54 to 56 are used to guide through spring plates which are drawn from the spring device ( Figure 5 The spring element 8) starts and presses against the rotor body ( Figure 5 4) preloaded. The sheet metal strip 57 with through holes 51 to 56 can also be considered as a ring body ( Figure 5 45) when the unfolded piece 50 or intermediate product.

Claims

1. A tilting pad bearing (10) comprising tilting pads (1, 2, 3) which are positioned and held tiltably in a housing body (5) by means of a frame-like spring device (8) so that, during operation of the tilting pad bearing (10), a converging bearing gap is generated between the tilting pads (1, 2, 3) and a rotor body (4) which is mounted so as to be rotatable about an axis of rotation, wherein: Rolling bodies (6, 7; 20; 24; 44) are provided, which are arranged between the housing body (5) and the tilting pads (1, 2, 3), and a retaining frame (9) is provided for retaining the rolling bodies (6, 7; 20) in position between the housing body (5) and the tilting pads (1, 2, 3), characterized in that the retaining frame (9) has a through hole (19; 26; 51-52), the rolling bodies (6, 7; 20; 24; 44) being received in the through hole with clearance, so that the rolling bodies (6, 7; 20; 24; 44) have rolling contact outside the through hole (19; 26; 51-52) not only with the housing body (5) but also with the corresponding tilting pads (1, 2, 3).

2. The tilting pad bearing according to claim 1, characterized in that The rolling elements (24; 44) are embodied as rollers.

3. The tilting pad bearing according to claim 1, wherein: The rolling bodies (6, 6; 20) are embodied as balls.

4. The tilting pad bearing according to any one of claims 1 to 3, characterized in that The cage (9) comprises at least one simple annular body (11, 12; 31, 32; 45).

5. The tilting pad bearing according to any one of claims 1 to 3, characterized in that The tilting pads (1, 2, 3) are each provided with a spring element (13, 14, 15; 23; 27; 43) in order to position and hold the associated tilting pad (1, 2, 3) in the housing body (5) in a tiltable manner.

6. The tilting pad bearing according to claim 5, characterized in that The spring elements (13, 14, 15; 23; 27; 43) engage the associated tilting pads (1, 2, 3) at their circumferentially opposite ends.

7. The tilting pad bearing according to claim 5, characterized in that The spring element (23; 43) comprises at least one spring blade (21; 25) which is prestressed inwardly against the associated tilting pad (1).

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