Bearing structure

Abstract

To provide a bearing structure that can improve the degrees of freedom in attitude of a bearing member and prevent vibration of a rotary shaft and damage of a bearing due to attitude fluctuation.SOLUTION: A bearing structure includes: a rotary shaft supported inside a housing 10; a bearing member 40 disposed coaxially with the rotary shaft; an elastic body 50 disposed on an outer peripheral side of the bearing member 40 and disposed coaxially with the bearing member 40; and regulation members 30a, 30b disposed in an outer periphery of the elastic body 50 and supporting the elastic body 50 toward an axial center of the bearing member 40.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a bearing structure. [Background technology]

[0002] Patent Document 1 discloses a bearing structure including a hydrodynamic bearing having a rotating shaft, foil arranged around the rotating shaft to form a bearing surface, a foil holder that holds the foil, a bearing support member arranged around the hydrodynamic bearing to support the hydrodynamic bearing, and at least one elastic body arranged between the bearing support member and the foil holder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-131135 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a bearing structure that can improve the degree of freedom in the position of a bearing member and prevent damage to the bearing due to vibration and position fluctuations of a rotating shaft. [Means for solving the problem]

[0005] The bearing structure in the present disclosure comprises a rotating shaft supported inside a housing, a bearing member arranged coaxially with the rotating shaft, an elastic body arranged on the outer periphery of the bearing member and arranged coaxially with the bearing member, and a regulating member arranged on the outer periphery of the elastic body and supporting the elastic body toward the axial center of the bearing member. Effect of the Invention

[0006] According to the present disclosure, it is possible to support the radial load applied to the bearing member by the rotating shaft, and even if the rotation axis of the rotating shaft fluctuates in the radial direction, the rotating shaft undergoes precession, etc., the bearing position and attitude can be changed in accordance with the displacement of the rotating shaft. Therefore, the radial load and damping capacity can be applied by the elastic body of the bearing member without restricting the elastic body in a specific direction, improving the degree of freedom of the bearing member's attitude and preventing bearing damage due to vibration and attitude fluctuation of the rotating shaft. [Brief description of the drawings]

[0007] [Figure 1] Schematic diagram showing an air refrigerant type air conditioner according to a first embodiment. [Diagram 2] FIG. 1 is a cross-sectional view showing details of an air refrigerant type air conditioner to which the bearing structure according to the first embodiment is applied; [Diagram 3] FIG. 1 is a side view of a bearing structure according to a first embodiment, as viewed from a rotation axis direction; [Figure 4] Cross-sectional view taken along line AA in Figure 3. [Diagram 5] FIG. 1 is a front view of a restricting member according to the first embodiment; [Figure 6] Cross-sectional view taken along line BB in FIG. [Figure 7] FIG. 11 is a side view of the bearing member and the elastic body support member as viewed from the rotation axis direction. [Figure 8] Cross-sectional view taken along line CC in FIG. [Figure 9] Enlarged view of the elastic body part in Figure 8 [Figure 10] Graph showing the relationship between the rotational frequency of a rotating shaft and the shaft end vibration amplitude in the bearing structure according to the first embodiment and in a conventional bearing structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (The knowledge and other information that formed the basis of this disclosure) At the time the inventors came up with the present disclosure, a bearing structure existed that was able to prevent the critical speed from increasing to high frequencies and assist in damping capacity under conditions where the bearing stiffness of a dynamic gas bearing applied to a rotating shaft exhibits extremely high stiffness as the rotating shaft rotates at high speeds.

[0009] However, the inventors discovered a problem with such conventional technology in that, in order to allow the dynamic gas bearing to freely change its position in the radial direction, when axial displacement or both axial and radial displacements are applied, the position of the bearing relative to the rotating shaft changes from a predetermined position and does not return to its original position. In order to solve this problem, the inventors have come up with the subject matter of the present disclosure. The present disclosure provides a bearing structure that can improve the degree of freedom in the position of a bearing member and prevent damage to the bearing due to vibration and position fluctuations of a rotating shaft.

[0010] Hereinafter, the embodiments will be described in detail with reference to the drawings. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming more redundant than necessary and to facilitate understanding by those skilled in the art. It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0011] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to the drawings. [1-1-1. Configuration of air refrigerant type air conditioner] FIG. 1 is a schematic diagram showing an air refrigerant type air conditioner to which a bearing structure according to a first embodiment is applied. As shown in Fig. 1, an air refrigerant type air conditioner 1 includes a cylindrical housing 10. A rotating shaft 11 is disposed inside the housing 10 along the axial direction of the housing 10. The rotating shaft 11 is rotatably supported by bearings provided on both sides of the housing 10. A motor 12 for driving the rotating shaft 11 to rotate is disposed approximately in the center of the rotating shaft 11 .

[0012] A compressor 13 is provided at one end of the rotating shaft 11. The compressor 13 includes an impeller 20 (see FIG. 2) that is rotationally driven by the rotation of the rotating shaft 11. An expander 14 is provided at the other end of the rotating shaft 11. The expander 14 includes a wheel 21 (see FIG. 2) that is rotated by the rotation of the rotating shaft 11.

[0013] A compressed air suction port 15 is provided at the end of the housing 10 on the compressor 13 side. A compressed air discharge port 16 is provided at the side of the housing 10 on the compressor 13 side. An expanded air intake port 17 is provided on the side of the housing 10 facing the expander 14. An expanded air discharge port 18 is provided on the end of the housing 10 facing the expander 14. Then, by driving the motor 12 to rotate the rotating shaft 11, the impeller 20 of the compressor 13 and the wheel 21 of the expander 14 are rotated together. As a result, air sucked in from the compressed air suction port 15 is compressed by the rotation of the impeller 20 and discharged from the compressed air discharge port 16 as high-temperature, high-pressure air. On the other hand, air sucked in through the expansion air intake port 17 is expanded by the rotation of the wheel 21 and is discharged from the expansion air discharge port 18 as low-temperature air.

[0014] Moreover, an air flow path 19 that communicates with the inside of the housing 10 is formed on the outer periphery side of the motor 12 of the housing 10. In this embodiment, the compressed air discharge port 16 of the compressor 13 is connected to the air flow path 19. As a result, the air sent from the compressed air discharge port 16 of the compressor 13 circulates through the air flow path 19 of the housing, and then is released into the atmosphere.

[0015] [1-1-2. Bearing structure configuration] Fig. 2 is a cross-sectional view showing details of an air refrigerant type air conditioner to which the bearing structure of the present disclosure is applied. Fig. 3 is a side view of the bearing structure in the first embodiment as viewed from the rotational axis direction. Fig. 4 is a cross-sectional view taken along line AA in Fig. 3. Fig. 5 is a front view of a restricting member in the first embodiment. Fig. 6 is a cross-sectional view taken along line BB in Fig. 5. Fig. 7 is a side view of the bearing member and the elastic body support member as viewed from the rotational axis direction. Fig. 8 is a cross-sectional view taken along line CC in Fig. 7. Fig. 9 is an enlarged view of the elastic body portion in Fig. 8.

[0016] As shown in FIGS. 2 to 4, a cylindrical opening 22 for supporting the rotating shaft 11 is formed in the housing 10 on the mounting side of the wheel 21 that constitutes the expander 14. A support surface 23 perpendicular to the axial direction of the rotating shaft 11 is formed inside the opening 22 . As shown in Fig. 4, two regulating members 30a, 30b are attached to the inside of the opening 22. As shown in Fig. 5 and Fig. 6, the regulating member 30a located on the central side of the rotating shaft 11 includes a regulating portion 31a located on the inner circumferential surface of the opening 22 and an attachment portion 32a extending along the support surface 23 to the outer circumferential side. In addition, the regulating member 30b located on the end side of the rotating shaft 11 has a regulating portion 31b located on the inner surface of the opening 22 and an attachment portion 32b extending radially outward along the outer end surface of the opening 22.

[0017] The restricting member 30 a located on the central side of the rotating shaft 11 is fixed to the housing 10 by fastening the mounting portion 32 a to the support surface 23 with a bolt 33 . The restricting member 30 b located on the end side of the rotating shaft 11 is fixed to the housing 10 by fastening an attachment portion 32 a to the end face of the opening 22 with a bolt 33 . The fixing positions of each regulating member 30a, 30b using bolts 33 are provided at multiple predetermined intervals around the circumference of the regulating members 30a, 30b, and in this embodiment, eight fixing positions are provided at equal intervals around the circumference of the regulating members 30a, 30b. The restricting portions 31a of the restricting members 30a and 30b each have a restricting surface 34 formed on an inner peripheral surface thereof, the restricting surface 34 being inclined at an angle of approximately 45°.

[0018] 7 to 9, a bearing member 40 is provided on the outer periphery of the rotating shaft 11. The bearing member 40 is formed in a cylindrical shape. A bearing (not shown) such as a dynamic pressure gas bearing is provided on the inner periphery of the bearing member 40. An elastic body support member 41 is provided on the outer circumferential side of the bearing member 40. The elastic body support member 41 has a cylindrical shape and is disposed coaxially with the bearing member 40. The elastic body support member 41 includes a support surface 42 that comes into contact with the inner peripheral surface of the regulating member 30 , and a support portion 43 that protrudes outwardly in the space between each of the regulating members 30 . Elastic body support portions 44 are provided at both axial end portions of the support portion 43 at positions facing the restriction surfaces 34 of the respective restriction members 30 . The elastic body support portion 44 is formed in a concave shape having a quadrant cross-sectional shape equal to the cross-sectional diameter of the elastic body 50 .

[0019] An annular elastic body 50 made of rubber or the like is attached to the elastic body support portion 44. The elastic body 50 is supported in a state of contact with the regulating surfaces 34 of the respective regulating members 30a, 30b.

[0020] In this embodiment, as shown in FIG. 4, the restricting member 30a located on the central side of the rotating shaft 11 has its attachment portion 32a fixed to the housing 10 via a washer 60 against the support surface 23. It is possible to change the thickness dimension of the washer 60. By changing the thickness dimension of the washer 60, it is possible to change the compression allowance of the elastic body 50, which will be described later, and thus it is possible to adjust the reaction force of the elastic body 50.

[0021] For example, when the thickness dimension of the washer 60 is large, the distance between the regulating surfaces 34 of the regulating members 30a, 30b can be made wider, thereby making it possible to reduce the reaction force of the elastic body 50. On the other hand, when the thickness dimension of the washer 60 is small, the distance between the regulating surfaces 34 of the regulating members 30a, 30b can be made small, thereby making it possible to increase the reaction force of the elastic body 50. In this way, by changing the thickness dimension of the washer 60, the amount of load applied by the elastic body 50 can be changed as necessary.

[0022] [1-2. Operation] Next, the operation of this embodiment will be described. In this embodiment, when the motor is driven to rotate, the rotating shaft is supported by the bearings of the bearing member 40 and rotates at high speed. In this case, when the rotating shaft 11 rotates, the rotating shaft may move radially or precess, causing the rotating shaft 11 to vibrate.

[0023] However, in this embodiment, an elastic body 50 is disposed between the regulating members 30a, 30b and the elastic support member, and is configured so that the elastic body 50 can move along the regulating surfaces 34 of the regulating members 30a, 30b so as to be in a position where the vibrations caused by rotation are balanced when the rotating shaft 11 rotates. As a result, the position of the elastic body 50 moves in response to vibrations generated by rotation of the rotating shaft, making it possible to correct the position and attitude of the axis of the rotating shaft. In other words, when the rotating shaft 11 rotates, the elastic body 50 moves along the regulating surfaces 34 of the regulating members 30a, 30b, thereby having the function of moving the rotating shaft 11 around the axis of the rotating shaft 11, thereby making it possible to suppress vibration of the rotating shaft 11.

[0024] FIG. 10 is a graph showing the relationship between the rotational frequency of the rotating shaft and the shaft end vibration amplitude in the bearing structure according to the first embodiment and in a conventional bearing structure that does not use the restricting member 30 and the elastic body 50. In FIG. As shown in FIG. 10, when the rotating shaft was driven to rotate at a rotation speed of 1200 rps, a slight vibration amplitude was confirmed at a specific rotation frequency in the bearing structure of this embodiment using the regulating member 30 and the elastic body 50. On the other hand, in the conventional bearing structure that does not use the restricting member 30 and the elastic body 50, a high vibration amplitude was confirmed in the low and high rotational frequency ranges of the rotating shaft. This demonstrates that the bearing structure of this embodiment is effective in reducing vibrations of the rotating shaft.

[0025] [1-3. Effects, etc.] As described above, the bearing structure of this embodiment comprises a rotating shaft supported inside the housing 10, a bearing member 40 arranged coaxially with the rotating shaft, an elastic body 50 arranged on the outer periphery of the bearing member 40 and arranged coaxially with the bearing member 40, and regulating members 30a, 30b arranged on the outer periphery of the elastic body 50 and supporting the elastic body 50 toward the axial center of the bearing member 40. This makes it possible to support the radial load applied to the bearing member 40 by the rotating shaft, and even if the axis of rotation of the rotating shaft fluctuates in the radial direction or the rotating shaft undergoes precession, the bearing position and posture can be changed in accordance with the displacement of the rotating shaft. Therefore, the elastic body 50 of the bearing member 40 can apply a radial load and impart damping capacity without restricting the elastic body 50 in a specific direction, improving the degree of freedom of the posture of the bearing member 40 and making it possible to prevent bearing damage due to vibration and posture fluctuations of the rotating shaft.

[0026] In the bearing structure of this embodiment, the elastic body 50 is formed in an annular shape having a circular cross section. This makes it possible to maintain the rigidity of the elastic body 50 constant regardless of the direction from which the force acting on the bearing member 40 from the rotating shaft acts. Therefore, stable rotation can be maintained even if the attitude or position of the rotating shaft changes.

[0027] In addition, in the bearing structure of this embodiment, the bearing member 40 is provided with an elastic body support portion 44 having a quadrant cross-sectional shape equal to the cross-sectional diameter of the elastic body 50 that holds the elastic body 50 on its outer periphery, and the regulating members 30a, 30b are provided on their inner peripheries with regulating surfaces 34 that come into contact with the elastic body 50 and are inclined at a predetermined angle relative to the axial center of the rotating shaft. This allows the shaft core of the bearing member 40 to be automatically aligned during assembly, and the assembly process can be simplified by holding the bearing member 40 without restricting its behavior in one direction, thereby reducing manufacturing costs and maintaining more stable rotation of the rotating shaft.

[0028] In the bearing structure of this embodiment, the restricting member 30a is fixed to the housing 10 via a washer 60. This allows the reaction force of the elastic body 50 to be changed by changing the thickness dimension of the washer 60 to change the compression allowance of the elastic body 50. Therefore, a larger load can be applied as required.

[0029] Furthermore, in the bearing structure of this embodiment, the restricting members 30a, 30b have a plurality of mounting positions on the housing 10, and the mounting positions are arranged at predetermined intervals in the circumferential direction of the restricting members 30a, 30b. As a result, by attaching the restricting members 30a and 30b to the housing 10 at attachment positions spaced at predetermined intervals in the circumferential direction, the rigidity of the elastic body 50 can be made constant in the circumferential direction, and therefore more stable rotation of the rotating shaft can be maintained.

[0030] (Other embodiments) As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. In addition, it is also possible to combine the components described in the first embodiment to create new embodiments.

[0031] (Additional Note) The above description of the embodiments discloses the following techniques. (Technology 1) A bearing structure comprising: a rotating shaft supported inside a housing; a bearing member arranged coaxially with the rotating shaft; an elastic body arranged on the outer periphery of the bearing member and arranged coaxially with the bearing member; and a regulating member arranged on the outer periphery of the elastic body and supporting the elastic body toward the axial center of the bearing member. With this configuration, the radial load applied to the bearing member by the rotating shaft can be supported, and even if the axis of rotation of the rotating shaft fluctuates in the radial direction, the rotating shaft undergoes precession, etc., the bearing position and attitude can be changed in accordance with the displacement of the rotating shaft. Therefore, the radial load and damping capacity can be applied by the elastic body of the bearing member without restricting the elastic body in a specific direction, improving the degree of freedom of the bearing member's attitude and preventing bearing damage due to vibration and attitude fluctuations of the rotating shaft.

[0032] (Technical 2) The bearing structure according to Technical 1, wherein the elastic body is formed in an annular shape having a circular cross section. With this configuration, the rigidity of the elastic body can be kept constant regardless of the direction from which the force applied to the bearing member by the rotating shaft acts, so stable rotation can be maintained even if the attitude or position of the rotating shaft changes.

[0033] (Technology 3) The bearing member has an elastic body support part having a quadrant cross-sectional shape equal to the cross-sectional diameter of the elastic body that holds the elastic body on its outer periphery, and the regulating member has an inner periphery with a regulating surface that contacts the elastic body and is inclined at a predetermined angle with respect to the axis of the rotating shaft. With this configuration, the shaft core of the bearing member is automatically aligned during assembly, and the bearing member is held without being restricted in its behavior in one direction, simplifying the assembly process, thereby reducing manufacturing costs and maintaining more stable rotation of the rotating shaft.

[0034] (Technical 4) The bearing structure according to any one of Technical 1 to Technical 3, wherein the regulating member is fixed between the casing and the regulating member via a washer. With this configuration, the reaction force of the elastic body can be changed by changing the thickness dimension of the washer to change the compression allowance of the elastic body, so that a larger load can be applied as required.

[0035] (Technology 5) The bearing structure according to any one of Technology 1 to Technology 4, wherein the regulating member has a plurality of mounting positions on the housing, and the mounting positions are arranged at predetermined intervals in the circumferential direction of the regulating member. With this configuration, by attaching the restricting members to the housing at attachment positions spaced at predetermined intervals in the circumferential direction, the rigidity of the elastic body can be made constant in the circumferential direction, thereby maintaining more stable rotation of the rotating shaft. [Industrial Applicability]

[0036] INDUSTRIAL APPLICABILITY The present disclosure can be suitably used as a bearing structure that improves the degree of freedom of the posture of a bearing member and can prevent bearing damage due to vibration and posture fluctuations of a rotating shaft. [Explanation of symbols]

[0037] 1. Air refrigerant type air conditioner 10. Chassis 11 Rotating shaft 12 Motor 13 Compressor 14 Expander 20 Impeller 21 Wheels 22 Aperture 23 Support surface 30 Regulatory Materials 31 Regulatory Department 32 Mounting part 33 Volts 34 Regulatory aspects 40 Bearing material 41 Elastic support member 42 Support surface 43 Support part 44 Elastic support part 50 Elastic Body 60 Washer

Claims

1. a rotating shaft supported within the housing; a bearing member arranged coaxially on the rotating shaft; an elastic body that is arranged on an outer circumferential side of the bearing member and is arranged coaxially with the bearing member; a restricting member that is disposed on an outer periphery of the elastic body and supports the elastic body toward the axial center of the bearing member, Bearing structure.

2. The elastic body is formed in a circular ring shape having a circular cross-sectional shape. The bearing structure according to claim 1.

3. the bearing member includes an elastic body support portion having a quadrant cross-sectional shape equal to a cross-sectional diameter of the elastic body that holds the elastic body on an outer periphery thereof, The inner periphery of the regulating member is provided with a regulating surface that is in contact with the elastic body and is inclined at a predetermined angle with respect to the axis of the rotating shaft. The bearing structure according to claim 2.

4. The restricting member is fixed to the housing via a washer. The bearing structure according to claim 1.

5. the restricting member has a plurality of attachment positions on the housing, The mounting positions are arranged at predetermined intervals in the circumferential direction of the regulating member. The bearing structure according to claim 1.

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