Film storage device

Abstract

In the present invention, a film bearing device rotatably supports a rotating shaft comprises an annular element having an insertion hole through which the rotating shaft is inserted, a cover film with an arcuate cross-section positioned between the inner circumferential surface of the annular element and the outer circumferential surface of the rotating shaft such that it surrounds the entire outer circumference of the rotating shaft, and a bumped film that supports the cover film from the outer circumferential side of the cover film and is supported on the inner circumferential surface of the annular element.In a cross-section perpendicular to the centerline of the cover sheet, the cover sheet contains a first region in which at least one through-hole formed across the cover sheet has an angular position of 240 degrees or more and less than 360 degrees, and a second region in which the angular position where there are no through-holes formed across the cover sheet is equal to or greater than 0 degrees and less than 240 degrees, where 0 degrees is considered to be the angular position of a virtual line extending upwards from the centerline of the cover sheet in the direction of gravity, the angular position increasing as the imaginary line rotates in the direction of rotation of the rotating shaft, with the centerline of the cover sheet serving as the center of rotation, and 360 degrees is considered to be the angular position when the imaginary line has completed a rotation.

Description

Technical field

[0001] The present disclosure relates to a foil bearing device that rotatably mounts a rotor. State of the art

[0002] A foil bearing consists of a cover foil, which provides a bearing surface for the rotor of a turbo blower or turbo compressor, and a raised foil that elastically supports the cover foil. As the rotor rotates, a fluid film (air film) forms between the bearing surface of the cover foil and the rotor, and the rotor is rotatably mounted via this air film. Because a suitable air film is automatically formed according to the rotor's rotational speed, the foil bearing is particularly effective when used on a rotor rotating at high speed.

[0003] To stably mount the rotor with the air film, it is necessary to maintain the pressure of the air film appropriately. For example, PTL 1 discloses a film bearing device that includes a valve which opens and closes a communication hole formed in a cover film according to the pressure (dynamic pressure) of an air film. List of citations from patent literature

[0004] [PTL 1] Japanese unexamined patent application publication no. 2021-046913 Summary of the invention: Technical problem

[0005] The air film contains a region (reduced pressure region) where the air film spreads towards a downstream side in one direction of rotation of the rotor. In the reduced pressure region, the pressure of the air film becomes a vacuum, and this vacuum acts as an excitation force that oscillates the rotor, which can reduce the rotor's vibration stability. PTL 1 proposes, however, that if the dynamic pressure of the air film increases outside the reduced pressure region, the valve opens to release the dynamic pressure towards an outer circumferential side of the cover film, but it does not propose a solution to the problem of generating the vacuum in the reduced pressure region.

[0006] The present disclosure was made with regard to the problems described above, and one objective of the present disclosure is to provide a foil bearing device capable of improving the vibration stability of a rotor. Solution to the problem

[0007] To achieve the above objective, a foil bearing device is provided according to the present disclosure, which rotatably supports a rotor, the foil bearing device comprising: an annular element having an insertion hole through which the rotor is inserted; a cover foil with an arcuate cross-section, arranged to surround an entire outer circumference of the rotor between an inner surface of the annular element and an outer surface of the rotor; and a bump foil, which supports the cover foil from an outer circumferential side of the cover foil and which is supported on the inner surface of the annular element, wherein, when in a cross-section perpendicular to a centerline of the cover foil an angular position of an imaginary line extending upward from the centerline of the cover foil in a direction of gravity is set to 0 degrees, the angular position increases,When the imaginary line rotates in a direction of rotation of the rotor, with the center line of the cover film serving as a center of rotation, and the angular position when the imaginary line rotates is defined as 360 degrees, the cover film comprises a first region in which the angular position at which at least one through-hole penetrating the cover film is formed lies in a range of 240 degrees or more and less than 360 degrees, and a second region in which the angular position at which no through-hole penetrating the cover film is formed lies in a range of 0 degrees or more and less than 240 degrees. Advantageous effects of the invention,

[0008] According to the foil bearing device of the present disclosure, it is possible to improve the vibration stability of the rotor. Brief description of the drawings Fig. Figure 1 is a diagram schematically showing a configuration of an electric compressor which includes a film storage device according to some embodiments. Fig. Figure 2 is a cross-sectional view that schematically shows a configuration of a film storage device according to one embodiment. Fig. 3 is a developed view of an inner surface of a cover film according to one embodiment. Fig. 4 is a diagram showing an example of a state in which a Fig. 2. The rotor shown is rotated. Fig. 5 is a graph that shows a relationship between an angular position, the Fig. 4 corresponds to, and shows the pressure of an air film. Fig. Figure 6 shows a developed view of an inner surface of a cover film according to a further embodiment. Fig. 7 is a developed view of an inner surface of a cover film according to a further embodiment. Fig. Figure 8 is a diagram that schematically shows a configuration of a cover sheet according to yet another embodiment. Description of embodiments

[0009] A film storage device according to one embodiment of the present disclosure is described below based on the drawings. Such an embodiment illustrates one aspect of the present disclosure, does not limit this disclosure, and may be optionally modified within the scope of the technical concept of the present disclosure.

[0010] Fig. Figure 1 is a diagram schematically showing a configuration of an electric compressor 100, which includes a film storage device 1 according to some embodiments. As in Fig. As shown in Figure 1, the electric compressor 100 comprises a rotor 102, an electric motor 104 which rotates the rotor 102, an impeller 106 which compresses a fluid by rotating integrally with the rotor 102, a housing 108 which accommodates the electric motor 104 and the impeller 106, and the foil bearing device 1.

[0011] The foil bearing device 1 rotatably supports the rotor 102. The foil bearing device 1 supports the rotor 102 in a state of contact with the rotor 102 until the rotational speed of the rotor 102 reaches a lift-off speed at which the rotor 102 becomes suspended. When the rotational speed of the rotor 102 reaches the lift-off speed, the foil bearing device 1 supports the rotor 102 in a non-contact state via a fluid film (hereinafter referred to as an air film A) formed between an inner surface 5 (a bearing surface) of a cover film 4 and an outer surface 110 of the rotor 102.

[0012] The present disclosure illustrates an example case in which the foil bearing device 1 is applied to the electric compressor 100. However, a device to which the foil bearing device 1 is applied is not limited to the electric compressor 100. The foil bearing device 1 according to the present disclosure is applied to a rotary device containing the rotor 102, in particular a rotary device containing the rotor 102 that can rotate at a high speed. For example, the rotary device includes a turbocharger or a turbo blower. <folienlagervorrichtung>(Configuration)

[0013] The configuration of the film storage device 1 according to one embodiment is described. Fig. Figure 2 is a cross-sectional view schematically showing the configuration of the foil bearing device 1 according to one embodiment, and shows the foil bearing device 1 cut in a direction perpendicular to an axial direction (hereinafter referred to as an axial direction D1) of the rotor 102. As in Fig. As shown in Figure 2, the film storage device 1 contains a ring-shaped element 2, the cover film 4 and a bumped film 6.

[0014] The annular element 2 has an insertion hole 3 through which the rotor 102 is inserted. In one embodiment, the annular element 2 has a cylindrical shape, and its inner diameter is larger than the outer diameter of the rotor 102. In some embodiments, the housing 108 of the electric compressor 100 described above incorporates the annular element 2. In this case, the annular element 2 is part of the housing 108.

[0015] The cover sheet 4 has an arc shape and is arranged such that it surrounds the entire outer circumference of the rotor 102 between an inner surface 7 of the annular element 2 and the outer surface 110 of the rotor 102. The cover sheet 4 is formed, for example, by bending a flexible stainless steel metal sheet into a cylindrical shape. In the Fig. In the form shown in Figure 2, an end section 10 of the cover film 4 is bent outwards in a circumferential direction D2 (hereinafter referred to as a "circumferential direction D2") and in a radial direction D3 (hereinafter referred to as a "radial direction D3"). The cover film 4 is arranged within the annular element 2 in a state in which one end section 10 in the circumferential direction D2 is held by the annular element 2. The other end section 12 of the cover film 4 in the circumferential direction D2 is slightly separated from the one end section 10 in the circumferential direction D2. In the form shown in Figure 2, the end section 10 is bent outwards in a radial direction D3. Fig. In the form shown in Figure 2, the cover film 4 is formed from a single metal sheet, and the outflow of the air film A from locations other than a through-hole 8 (which will be described later) to the outside of the cover film 4 is eliminated. Therefore, the operation and effect, which will be described later, can be easily achieved. However, the present disclosure is not limited to this form. Although not shown in the drawings, in some embodiments the film storage device 1 includes several cover films 4 that are separated from one another and arranged continuously along the circumferential direction D2.

[0016] In the present disclosure, the circumferential direction D2 is a circumferential direction centered on a center line O1 of the cover film 4. Regarding the paper surface of Fig. 2 is defined as a direction (left direction) from the other end section 12 of the cover sheet 4 towards one end section 10 as a side in the circumferential direction D2, and a direction (right direction) from one end section 10 of the cover sheet 4 towards the other end section 12 is defined as the other side in the circumferential direction D2. The radial direction D3 is a direction perpendicular to the center line O1, and a direction approaching the center line O1 is defined as an inner side in the radial direction D3, and a direction separated from the center line O1 is defined as an outer side in the radial direction D3.

[0017] The textured foil 6 has an arc shape and is arranged so that it surrounds the entire outer circumference of the cover foil 4. The textured foil 6 is supported on the inner surface 7 of the annular element 2. The textured foil 6 is formed, for example, by bending a flexible stainless steel metal sheet into a tubular shape. In the Fig. In the form shown in Figure 2, the bumpy foil 6 extends over the entire circumferential direction D2 and is in contact with the inner surface 7 of the annular element 2. The bumpy foil 6 is configured such that it allows one end section 10 of the cover foil 4 to pass through the bumpy foil 6. Although not shown in the drawings, in some embodiments the foil storage device 1 contains several bumpy foils 6 that are separated from one another and arranged continuously along the circumferential direction D2.

[0018] The textured foil 6 contains several textured sections 14 that project towards the cover foil 4, and at least a portion of each textured section 14 rests against the cover foil 4. Each of the multiple textured sections 14 projects in a direction separated from the inner surface 7 of the annular element 2 (i.e., towards the inner side in the radial direction D3) and is curved in an arc. The tip of each of the multiple textured sections 14 rests against the cover foil 4. The multiple textured sections 14 are spaced apart along the circumferential direction D2, and the textured foil 6 has a corrugated shape. The textured foil 6 is designed to elastically support the cover foil 4.

[0019] As in Fig. As shown in Figure 2, in a cross-sectional view obtained by cutting the foil bearing device 1 in a direction perpendicular to the axial direction D1 of the rotor 102, the angular position θ of an imaginary line L extending upwards from the centerline O1 of the cover foil 4 in a gravitational direction D4 is defined as 0 degrees. The angular position θ increases when the imaginary line L rotates in the circumferential direction D2, which is the direction of rotation of the rotor 102, in the opposite direction (counterclockwise), with the centerline O1 of the cover foil 4 serving as a center of rotation, and the angular position θ when the imaginary line L completes a rotation is defined as 360 degrees. In the Fig. In the form shown in Figure 2, the other end section 12 of the cover sheet 4 is located at the angular position θ of 350 degrees or more and less than 360 degrees.

[0020] Fig. Figure 3 shows a developed view of the inner surface 5 of the cover film 4 according to one embodiment. As in Fig. As shown in Figure 3, the cover sheet 4 contains a first region R1, in which the angular position θ lies within a range of 240 degrees or more and less than 360 degrees, and a second region R2, in which the angular position θ lies within a range of 0 degrees or more and less than 240 degrees. In the first region R1, the cover sheet 4 has several through holes 8 that are formed such that they penetrate the cover sheet 4. On the other hand, in the second region R2, the through hole 8 that penetrates the cover sheet 4 is not formed in the cover sheet 4.

[0021] At the in Fig. In the form shown in Figure 3, the multiple through-holes 8 in the first region R1 comprise a first through-hole 8A (8) and a second through-hole 8B (8), which have an angular position θ that differs from the angular position θ of the first through-hole 8A. In other words, each of the first through-holes 8A and the second through-holes 8B is arranged along the circumferential direction D2. The first through-hole 8A and the second through-hole 8B overlap at least partially in the axial direction D1. The multiple through-holes 8 further comprise a third through-hole 8C (8), which is arranged on the side opposite the first through-holes 8A, with the second through-hole 8B inserted between them in the circumferential direction D2. The first through-hole 8A, the second through-hole 8B, and the third through-hole 8C each have a circular shape with the same diameter.

[0022] At the in Fig. In the form shown, the multiple through holes 8 comprise the first through hole 8A and a first through hole 8D (8) in the axial direction, arranged along the axial direction D1, in the first region R1. The first through hole 8A and the first through hole 8D in the axial direction overlap at least partially in the circumferential direction D2. The multiple through holes 8 further comprise a second through hole 8E (8) in the axial direction, arranged on the side opposite the first through holes 8A, with the first through hole 8D in the axial direction D1 inserted between them. The first through hole 8A, the first through hole 8D in the axial direction, and the second through hole 8E in the axial direction each have a circular shape with the same diameter. (Processes and effects)

[0023] The operation and effects of the foil storage device 1 according to one embodiment are described. Fig. 4 is a diagram showing an example of a state in which the in Fig. 2 Rotor 102 shown is rotated, and the rotor 102 is rotated at a speed equal to or higher than the take-off speed.

[0024] As in Fig. As shown in Figure 4, the film bearing device 1 supports the rotor 102 in a non-contact state with the rotor 102 via the air film A. The rotor 102 tends to fall due to its own weight. Furthermore, due to rotation, the rotor 102 approaches a section at an angular position θ of 180 degrees or more of the inner surface 5 of the cover film 4. That is, at the paper surface of Fig. 4. Due to rotation, rotor 102 moves to the right. For this reason, in a Fig. In the case shown in Figure 4, the air film A is thinnest at the angular position θ of 210 degrees. The air film A thins from the angular position θ of 0 degrees to the angular position θ of 210 degrees and thickens from the angular position θ of 210 degrees to the angular position θ of 360 degrees (the thickness of the air film A increases).

[0025] Fig. 5 is a graph that shows a relationship between the angular position θ, the Fig. 4 corresponds to, and shows the pressure of the air film A. In Fig. In figure 5, the horizontal axis indicates the angular position θ, and the vertical axis indicates the pressure of the air film A. The pressure of the air film A in Fig. 5 is given as a manometer pressure and becomes 0 Pa in a case where the pressure of the air film A is identical to the pressure (atmospheric pressure) around the air film A. Then a pressure of less than 0 Pa is defined as a negative pressure, and a pressure of 0 Pa or more is defined as a positive pressure. Fig. 5 is the pressure of the air film A in a case where the rotor 102 is supported by the foil bearing device 1 according to one embodiment, P1, and is indicated by a solid line. Furthermore, the pressure of the air film A in a case where the multiple through-holes 8 are not formed in the first region R1 of the cover film 4 (a comparative example), P2, is indicated by a dashed line.

[0026] As in Fig. As shown in Figure 4, when the rotor 102 rotates, in the first region R1, where the angular position θ is in a range of 240 degrees or more and less than 360 degrees, the air film A becomes thinner as the angular position θ increases, and the pressure of the air film A decreases. For this reason, as shown in Fig. Figure 5 shows that in the first area R1, the pressure of the air film A can become a vacuum. The vacuum acts as an excitation force that vibrates the rotor 102 and reduces the vibration stability of the rotor 102.

[0027] According to one embodiment, since the multiple through-holes 8 are formed in the first region R1 of the cover film 4, air flows through the multiple through-holes 8 into the air film A on an outer circumferential side of the cover film 4, even if the pressure of the air film A becomes a vacuum, and it is prevented that the pressure of the air film A becomes a vacuum. That is, as in Fig. As shown in Figure 5, this prevents the pressure of the air film A from falling below 0 Pa. Therefore, it is possible to suppress an increase in the excitation force and improve the vibration stability of the rotor 102.

[0028] However, in a case where the through-holes 8 are formed over the entire circumference of the cover film 4, the pressure of the air film A supporting the rotor 102 is reduced, the air film A becomes thinner, and there is concern that the rotor 102 may come into contact with the cover film 4. According to one embodiment, since the through-hole 8 is not formed in the second region R2 of the cover film 4, it is possible to suppress a decrease in the pressure of the air film A and to prevent contact between the rotor 102 and the cover film 4. In particular, as shown in Fig. As shown in Figure 5, the air film A in the second region R2 is often under an overpressure of 0 Pa or higher, unlike the air film A in the first region R1. Therefore, it is not necessary to allow air to flow through the through-hole 8 into the air film A in the second region R2. Rather, the through-hole 8 is not formed in the second region R2 of the cover film 4, thus preventing the air film A in the second region R2 from flowing out to the outer circumferential side of the cover film 4 via the through-hole 8. Therefore, the pressure of the air film A, which is capable of adequately supporting the rotor 102, can be ensured. Furthermore, in particular, the pressure of the air film A at the angular position θ of 210 degrees can be maintained at a high overpressure, and the rotor 102 can be stably supported.

[0029] As in Fig. As shown in Figure 5, the pressure of the air film A has a different order of magnitude depending on the angular position θ. According to one embodiment, the first through-hole 8A, the second through-hole 8B, and the third through-hole 8C are each arranged such that their angular position θ corresponds to the angular position, thus further improving the vibration stability of the rotor 102. The diameter of the first through-hole 8A, the second through-hole 8B, and the third through-hole 8C can differ from one another, and the first through-hole 8A, the second through-hole 8B, and the third through-hole 8C can have shapes ranging from circular to rectangular.

[0030] The pressure of the air film A can have different orders of magnitude depending on the axial direction D1. According to one embodiment, the first through-hole 8A, the first through-hole 8D in the axial direction, and the second through-hole 8E in the axial direction are each arranged such that they correspond to the order of magnitude of the pressure of the air film A in the axial direction D1, thus further improving the vibration stability of the rotor 102. The diameter of each of the first through-hole 8A, the first through-hole 8D in the axial direction, and the second through-hole 8E in the axial direction can differ from one another, and the first through-hole 8A, the first through-hole 8D in the axial direction, and the second through-hole 8E in the axial direction can have shapes other than a circle, such as a rectangular shape.

[0031] In some embodiments, the shape and position of each of the multiple through-holes 8 in the foil bearing device 1 are determined based on the weight of the rotor 102 and the rated speed of the rotor 102 (i.e., the magnitude of the vacuum). In some embodiments, the density or the number of multiple through-holes 8 in the foil bearing device 1 is determined based on the weight of the rotor 102 and the rated speed of the rotor 102.

[0032] In some embodiments, the multiple through-holes 8 are formed in a section at the angular position θ in a range of 240 degrees or more and less than 300 degrees in the first region R1 of the cover sheet 4. In this case, the through-hole 8 need not be formed in a section where the angular position θ of the cover sheet 4 lies in a range of 300 degrees or more and less than 360 degrees. According to such a configuration, in a case where the cover sheet 4 is configured to close the gap between one end section 10 and the other end section 12, the strength of each end section 10 and the other end section 12 can be maintained.

[0033] In some embodiments, the multiple through-holes 8 comprise a large-diameter hole and a small-diameter hole, the latter having a diameter smaller than that of the large-diameter hole, arranged along the axial direction D1. In a flattened view, where the inner surface 5 of the cover film 4 is unwound, the distance of the large-diameter hole to an imaginary straight line passing through the center of the cover film 4 in the axial direction D1 is shorter than that of the small-diameter hole. In the first region R1 of the air film A, the absolute value of the negative pressure on a central side in the axial direction D1 can be large. According to such a configuration, the negative pressure on the central side of the air film A can be effectively suppressed or eliminated.

[0034] In one embodiment, the multiple through-holes 8, each having a circular shape, are formed in the cover film 4. However, the present disclosure is not limited to this form. Fig. Figure 6 shows a developed view of the inner surface 5 of the cover film 4 according to a further embodiment. Fig. Figure 7 shows a developed view of the inner surface 5 of the cover film 4 according to a further embodiment. Fig. Figure 8 is a diagram that schematically shows a configuration of the cover sheet 4 according to yet another embodiment.

[0035] In another embodiment, as in Fig. Figure 6 shows a through-hole 8 formed in the cover film 4. The through-hole 8 contains a slot 20 (8) which has a cutout section 22 in the axial direction and a pair of cutout sections 24A and 24B in the rotational direction.

[0036] The axial cutout section 22 is cut out in a linear shape along the axial direction D1. Each of the pair of cutout sections 24A and 24B in the rotational direction is cut out in a linear shape from the axial cutout section 22 to one side in the circumferential direction D2, which is an upstream side in the rotational direction. The pair of cutout sections 24A and 24B in the rotational direction are arranged side by side along the axial direction D1. The pair of cutout sections 24A and 24B in the rotational direction overlap at least partially in the axial direction D1. The pair of cutout sections 24A and 24B in the rotational direction face each other. The slot 20 has a lateral U-shape that projects towards the other side in the circumferential direction D2.

[0037] At the in Fig. In the form shown in Figure 6, one end 4a on one side of the cover sheet 4 is set to a position of 0% relative to its length in the axial direction D1. This position increases from one end 4a of the cover sheet 4 to the other end 4b, and the other end 4b is defined as a position of 100% relative to its length in the axial direction D1. One end 22a of the cutout section 22 in the axial direction is located in a range of more than 0% and less than 10%, and the other end 22b is located in a range of more than 90% and less than 100%. One of the pair of cutout sections 24A in the direction of rotation is cut out from one end 22a of the cutout section 22 in the axial direction to one side in the circumferential direction D2.The other of the pair of cutout sections 24B in the direction of rotation is cut out from the other end 22b of the cutout section 22 in the axial direction to one side in the circumferential direction D2.

[0038] According to the in Fig. In the form shown in Figure 6, the laterally U-shaped slot 20 is formed so that, when the pressure of the air film A becomes a vacuum, a suction section 4c of the cover film 4, which is surrounded by the slot 20, can be drawn towards the rotor 102 and the thickness of the air film A can be made essentially uniform (a parallel gap can be formed). Therefore, a decrease in the pressure of the air film A due to the air film A spreading thicker when the angular position θ increases is suppressed, and it can be prevented that the pressure of the air film A becomes a vacuum.

[0039] According to the in Fig. In the form shown in Figure 6, one end 22a of the slot 20 is located in a range of more than 0% and less than 10%, and the other end 22b is located in a range of more than 90% and less than 100%. Therefore, it can be ensured that the suction sections 4c of the cover film 4 extend in the axial direction D1, and it is possible to prevent the pressure of the air film A from becoming a negative pressure over its entire length or most of its axial direction D1.

[0040] At the in Fig. In the form shown in Figure 6, the slot 20 has a lateral U-shape. However, the present disclosure is not limited to this form. The slot 20 can have any configuration as long as the suction section 4c is formed. For example, one of the pair of cutout sections 24A is cut out in the rotational direction between one end 22a and the other end 22b of the cutout section 22 in the axial direction towards one side in the circumferential direction D2.

[0041] In yet another embodiment, as described in Fig. Figure 7 shows the through hole 8 as an elongated hole 30 (8) with a rectangular shape extending along the axial direction D1. The elongated hole 30 has one end 30a located in a region of more than 0% and less than 10% of the length in the axial direction D1 of the cover sheet 4 described above, and the other end 30b located in a region of more than 90% and less than 100%. As shown in Fig. As shown in Figure 8, the elongated hole 30 and a tip 15 of the hump section 14 overlap in the circumferential direction D2 (the direction of rotation of the rotor 102). The tip 15 of the hump section 14 overlaps with a center 31 of the elongated hole 30 in the circumferential direction D2. The length of the elongated hole 30 in the circumferential direction D2 is less than the length of the hump section 14 in the circumferential direction D2.

[0042] According to the in Fig. 7 and Fig. In the form shown in Figure 8, even if the pressure of the air film A becomes a vacuum, air is allowed to flow through the elongated hole 30 into the air film A, which is under vacuum, thus preventing the pressure of the air film A from becoming a vacuum. Furthermore, if the pressure of the air film A becomes higher than a gauge pressure, the elongated hole 30 is blocked by the hump section 14, so that the outflow of the air film A is suppressed. For this reason, the pressure of the air film A, which is greater than the gauge pressure, can be ensured.

[0043] According to the in Fig. In the form shown in Figure 7, the elongated hole 30 has one end 30a, which is located in a region of more than 0% and less than 10%, and the other end 30b, which is located in a region of more than 90% and less than 100%. Therefore, it is possible to prevent the pressure of the air film A from becoming a negative pressure over its entire length or most of its axial direction D1.

[0044] In each of the embodiments described above, a case was described in which only the multiple circular through-holes 8A to 8E (which are shown in Fig. 3 (shape shown), the laterally U-shaped slot 20 (which is in Fig. 6 (as shown) or the elongated hole 30 is formed in the cover film 4. In some embodiments, at least two of the circular through-hole 8A, the slot 20 and the elongated hole 30 are formed in the cover film 4.

[0045] The contents described for each of the embodiments described above are understood, for example, as follows. [1] A foil bearing device (1) according to the present disclosure is a foil bearing device which rotatably supports a rotor (102), the foil bearing device comprising: a ring-shaped element (2) having an insertion hole (3) through which the rotor is inserted; a cover sheet (4) with an arc-shaped cross-section, arranged to surround an entire outer circumference of the rotor between an inner surface (7) of the annular element and an outer surface (110) of the rotor; and a bumped foil (6) which supports the cover foil from an outer circumferential side of the cover foil and which is supported on the inner surface of the ring-shaped element, wherein, in a cross-sectional view along a direction perpendicular to an axial direction (D1) of the rotor, an angular position (θ) of an imaginary line (L) extending upwards from a centerline (O1) of the cover sheet in a gravity direction (D4) is set to 0 degrees, the angular position increases when the imaginary line rotates in a direction of rotation of the rotor, the centerline of the cover sheet serving as a center of rotation, and the angular position when the imaginary line rotates is defined as 360 degrees, the cover sheet comprises a first area (R1) in which the angular position at which at least one through hole (8) penetrating the cover sheet is formed is in a range of 240 degrees or more and less than 360 degrees, and a second area (R2) in which the angular position at which a through hole penetrating the cover sheet is not formed is in a range of 0 degrees or more and less than 240 degrees.

[0046] As the rotor rotates, in the first region where the angular position is between 240 degrees and 360 degrees, the gap between the cover sheet and the rotor widens as the angular position increases. This can cause the pressure of the fluid film (air film) formed between the cover sheet and the rotor to drop, resulting in a vacuum. This vacuum acts as an excitation force, causing the rotor to oscillate and reducing its vibration stability. However, according to the configuration described above [1], because the through-hole is located in the first region of the cover sheet, even if the fluid film pressure becomes a vacuum, the fluid (air) on the outer circumferential side of the cover sheet flows through the through-hole into the fluid film, preventing the fluid film pressure from becoming a vacuum.Therefore, it is possible to suppress an increase in the excitation force and improve the vibration stability of the rotor.

[0047] However, in a case where through-holes are formed around the entire circumference of the cover film, the pressure of the fluid film supporting the rotor decreases, the fluid film becomes thinner, and there is a possibility that the rotor will come into contact with the cover film. According to the configuration above [1], since a through-hole is not formed in the second region of the cover film, it is possible to suppress a decrease in the pressure of the fluid film and thus prevent contact between the rotor and the cover film. In particular, the fluid film in the second region is often under positive pressure, unlike the fluid film in the first region. Therefore, it is not necessary to allow the fluid to flow through a through-hole into the fluid film in the second region.Rather, no through-hole is formed in the second area of ​​the cover film, thus preventing the fluid film from flowing out through a through-hole to the outer circumference of the cover film. Therefore, the pressure of the fluid film, which is capable of properly supporting the rotor, can be ensured.

[0048] [2] In some embodiments, the configuration described in [1] above includes, the at least one through hole several through holes (8A, 8D, 8E) which are arranged along an axial direction of the rotor in the first area.

[0049] The pressure of the fluid film can vary depending on the axial direction. According to the configuration shown above [2], the multiple through-holes are arranged to correspond to the order of magnitude of the pressure in the axial direction of the fluid film, thus further improving the vibration stability of the rotor.

[0050] [3] In some embodiments, the configuration described in [1] or [2] above includes, the at least one through hole a first through hole (8A) and a second through hole (8B) with an angular position that differs from an angular position of the first through hole in the first area.

[0051] The pressure of the fluid film has a magnitude that varies depending on the angular position. According to the configuration above [3], the first through-hole and the second through-hole are arranged to correspond to the angular positions, and thus the vibration stability of the rotor can be further improved.

[0052] [4] In some embodiments, the configuration described in one of the above [1] to [3] includes, the at least one through-hole a slot (20) which has a cutout section (22) in the axial direction, which is cut out along an axial direction of the rotor, and a pair of cutout sections (24A, 24B) in the direction of rotation, which are cut out from the cutout section in the axial direction to an upstream side in the direction of rotation and are aligned along the axial direction.

[0053] According to the configuration above [4], when the fluid film pressure becomes a vacuum, the section of the cover film surrounded by the slot is drawn towards the rotor, and the size of the gap between the section of the cover film and the rotor can be made uniform or substantially uniform. Therefore, it is possible to suppress a decrease in fluid film pressure due to the gap increasing as the angular position increases, and to prevent the fluid film pressure from becoming a vacuum.

[0054] [5] In some embodiments, in the configuration described in [4] above, if one end (4a) of the cover film is defined in the axial direction as a position of 0% with respect to a length of the cover film in the axial direction, the position increases from one end of the cover film to the other end (4b) and the other end is defined as a position of 100% with respect to the length of the cover film in the axial direction, the section cut out in the axial direction one end (22a) which is in a range of more than 0% and less than 10%, and the other end (22b) which is in a range of more than 90% and less than 100%, One of the pair of cutout sections (24A) in the direction of rotation is cut out from one end of the cutout section in the axial direction towards the upstream side in the direction of rotation, and The other of the pair of cutout sections (24B) in the direction of rotation is cut out from the other end of the cutout section in the axial direction towards the upstream side in the direction of rotation.

[0055] According to the configuration of the above [5] it is possible to prevent the pressure of the fluid film from becoming a vacuum over its entire length or most of its axial direction.

[0056] [6] In some embodiments, the configuration described in one of the above [1] to [5] includes, the bumped foil has a bumped section (14) that projects towards the cover foil, and the at least one through hole and one tip (15) of the hump section overlap in the direction of rotation of the rotor.

[0057] According to the configuration above [6], even if the fluid film pressure becomes a vacuum, the fluid (air) is allowed to flow through the through-hole into the vacuum-operated fluid film, thus preventing the fluid film pressure from becoming a vacuum. Furthermore, if the fluid film pressure becomes higher than a gauge pressure, the through-hole is blocked by the hump section, and the pressure of the fluid film, which is higher than the gauge pressure, is maintained. Reference symbol list 1 film storage device 2 ring-shaped element 3 insertion holes 4 Cover film 4a one end of cover film 4b other end of cover film 5 Inner surface of cover film 6 bump foil 7 Inner surface of ring-shaped element 8 through holes 8A first through hole 8B second through hole 14 Humer section 15 top 20 slots 22 Section in axial direction 22a one end of cutout section in axial direction 22b other end of cutout section in axial direction 24A one of a pair of cutout sections in the direction of rotation 24B the other of a pair of cutout sections in the direction of rotation 30 slotted holes 100 electric compressor 102 Rotor 104 Electric motor 106 wheel 108 cases 110 Outer surface area of ​​rotor A film of air D1 Axial direction D2 circumferential direction D3 Radial direction D4 Direction of gravity L imaginary line O1 Center line R1 first area R2 second area QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2021-046913

[0004] < / folienlagervorrichtung>

Claims

[1] A foil bearing device that rotatably supports a rotor, the foil bearing device comprising: a ring-shaped element that has an insertion hole through which the rotor is inserted; a cover film with an arc-shaped cross-section, arranged to encircle the entire outer circumference of the rotor between an inner surface of the annular element and an outer surface of the rotor; and a bumpy foil that supports the cover foil from an outer circumferential side of the cover foil and is supported on the inner circumferential surface of the ring-shaped element, wherein, in a cross-section perpendicular to an axis of the rotor, an angular position of an imaginary line extending upwards from a centerline of the cover sheet in a direction of gravity is set to 0 degrees, the angular position increases when the imaginary line rotates in a direction of rotation of the rotor, the centerline of the cover sheet serving as a center of rotation, and the angular position when the imaginary line makes a rotation is defined as 360 degrees, The cover film contains a first area in which the angular position at which at least one through-hole penetrating the cover film is formed lies in a range of 240 degrees or more and less than 360 degrees, and a second area in which the angular position at which a through-hole penetrating the cover film is not formed lies in a range of 0 degrees or more and less than 240 degrees. [2] Foil bearing device according to claim 1, wherein the at least one through hole comprises several through holes arranged along an axial direction of the rotor in the first region. [3] Film storage device according to claim 1 or 2, wherein the at least one through-hole comprises a first through-hole and a second through-hole with an angular position that differs from an angular position of the first through-hole in the first region. [4] Foil bearing device according to claim 1 or 2, wherein the at least one through hole includes a slot comprising a cutout section in the axial direction, which is cut out along an axial direction of the rotor, and a pair of cutout sections in the direction of rotation, which are cut out from the cutout section in the axial direction to an upstream side in the direction of rotation and are aligned along the axial direction. [5] Film storage device according to claim 4, where, if one end of the cover film is defined in the axial direction as a position of 0% with respect to a length of the cover film in the axial direction, the position increases from one end of the cover film to the other end, and the other end is defined as a position of 100% with respect to the length of the cover film in the axial direction, The section cutout has one end in the axial direction that lies in a range of more than 0% and less than 10%, and the other end that lies in a range of more than 90% and less than 100%. one of the pair of cutout sections is cut out in the direction of rotation from one end of the cutout section in the axial direction towards the upstream side in the direction of rotation, and the other of the pair of cutout sections is cut out in the direction of rotation from the other end of the cutout section in the axial direction towards the upstream side in the direction of rotation. [6] Film storage device according to claim 1 or 2, wherein the bumpy foil contains a bumpy section that protrudes towards the top foil, and The at least one through-hole and one tip of the hump section overlap in the direction of rotation of the rotor.

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