Bearing structure

Abstract

The utility model relates to a bearing structure, its characterized in that, including: a shaft, the inner race of the outer periphery of the sleeve set in the shaft, the plurality of rolling body of the outer periphery side of the inner race is provided, and the bearing component of the outer race of the rolling body is supported in the outer periphery side, and the casing of the bearing component is housed, wherein, the inner periphery surface of the inner race and the outer periphery surface of the shaft form the sliding surface that allows relative sliding, and at least one of the inner periphery surface of the inner race or the outer periphery surface of the shaft forms the plurality of grooves along the axial extension, through the groove, and cooling medium can flow into the sliding surface.

Description

Technical Field

[0001] This utility model relates to a bearing structure. Background Technology

[0002] Traditional bearings used to support rotating shafts widely employ a rolling bearing structure with an inner ring, outer ring, and rolling elements. These bearings achieve smooth rotation by using lubricating oil or grease to reduce friction between the rolling elements and the inner and outer rings. However, in extremely low-temperature environments, particularly liquid nitrogen (approximately -196°C) or liquid hydrogen (approximately -253°C), conventional lubricants freeze, leading to loss of lubrication. Furthermore, at extremely low temperatures, the different thermal contraction rates of the components cause changes in the clearance between the inner ring, outer ring, and rolling elements, potentially causing the rolling elements to solidify and hinder rotation. This results in increased friction, and the generated heat can cause the cooling medium to vaporize, leading to energy loss and reduced safety. To address these issues, a bearing structure capable of stable operation even at extremely low temperatures is urgently needed. Utility Model Content

[0003] The purpose of this invention is to provide a bearing structure that can smoothly maintain shaft rotation and effectively cool frictional heat even in extremely low temperature environments where lubricants cannot be used.

[0004] The first technical solution is a bearing structure comprising: a shaft; an inner ring sleeved on the outer periphery of the shaft; a plurality of rolling elements disposed on the outer periphery of the inner ring; and a bearing component supporting the rolling elements on the outer periphery of the outer ring; and a housing housing the bearing component; wherein a sliding surface is formed between the inner peripheral surface of the inner ring and the outer peripheral surface of the shaft, allowing relative sliding; and at least one of the inner peripheral surface of the inner ring or the outer peripheral surface of the shaft forms a plurality of axially extending grooves; through the grooves, a cooling medium can flow into the sliding surface. Attached Figure Description

[0005] Figure 1 This is a schematic cross-sectional view of the bearing structure cut along the axial direction.

[0006] Figure 2 It is a schematic partial cross-sectional view of a shaft and bearing component cut along a direction perpendicular to the axial direction. Detailed Implementation

[0007] The following will combine Figure 1 and Figure 2 This article describes one embodiment of the present invention in detail.

[0008] Figure 1 This invention relates to one embodiment of the bearing structure 10, and schematically shows a cross-sectional view taken along the axial direction X. Figure 2 for Figure 1 The bearing structure shown is a partial cross-sectional view cut along the X-axis perpendicular to the axial direction.

[0009] The bearing structure 10 includes a housing 12 and a shaft 14 that can be rotatably supported relative to the housing 12. The housing 12 is made of a material that maintains high rigidity and dimensional stability at extremely low temperatures, such as stainless steel or a cryogenic metal alloy, and has an internal accommodating space C. This accommodating space C can be filled with a cooling medium such as liquid nitrogen (approximately -196°C) or liquid hydrogen (approximately -253°C), and the bearing component 20 is housed in this space.

[0010] The bearing component 20 has a rolling bearing structure, consisting of an inner ring 22, an outer ring 26, and a plurality of rolling elements 24 disposed between them. The inner ring 22 is a cylindrical component fitted around the outer periphery of the shaft 14. The outer ring 26 is a cylindrical component disposed around the outer periphery of the inner ring 22 and fixed to the inner periphery of the housing 12. The outer circumferential surface of the inner ring 22 and the inner circumferential surface of the outer ring 26 respectively form arc-shaped rolling surfaces, and the plurality of rolling elements 24 are disposed between these rolling surfaces. The rolling elements 24 are, for example, made of ceramic balls or low-temperature resistant metal balls, and are arranged at circumferential intervals. The bearing component 20 with the above structure functions as a rolling bearing in a normal temperature environment.

[0011] A sliding surface that allows relative sliding is formed between the inner circumferential surface of the inner ring 22 and the outer circumferential surface of the shaft 14 in an extremely low temperature environment. At room temperature or above a set threshold temperature (e.g., about -100°C), the inner ring 22 is tightly fitted onto the shaft 14, and in a fixed state, the rotation of the rolling element 24 smoothly supports the rotation of the shaft 14.

[0012] When the cooling medium fills the containment space C and the temperature is below a set threshold temperature, a tiny gap is formed between the shaft 14 and the inner ring 22 due to the difference in thermal shrinkage rates of the materials. This allows for relative sliding between the inner ring 22 and the shaft 14. Even if the rolling element 24 is fixed at low temperatures, it will not hinder the rotation of the shaft 14. Therefore, the bearing structure 10 can function as a sliding bearing structure, thereby achieving a failure protection function in extremely low temperature environments.

[0013] like Figure 2 As shown, the inner circumferential surface of the inner ring 22 has multiple grooves 30 extending along the axial direction X. These grooves 30 are spaced apart circumferentially, serving as flow paths for guiding the cooling medium in the receiving space C to the sliding surface. This allows the cooling medium to flow into the gap between the inner ring 22 and the shaft 14 and flow along the friction surface, efficiently removing frictional heat.

[0014] The groove 30 can be formed not only on the inner circumferential surface of the inner ring 22, but also on the outer circumferential surface of the shaft 14. Regardless of the configuration, it can serve as a flow path for the cooling medium, reducing heat generation caused by friction. Furthermore, the cross-sectional shape of the groove 30 can be any shape, such as semi-circular, V-shaped, or rectangular, but it is preferable to adopt a shape that facilitates the flow of low-viscosity cooling media such as liquid hydrogen.

[0015] The working principle of bearing structure 10 is explained below.

[0016] In the bearing structure 10 of this invention, under normal temperature or above-threshold temperature conditions, the inner ring 22 is fixed to the shaft 14, and the rolling element 24 rotates to achieve the function of a conventional rolling bearing. However, in extremely low temperature environments below the threshold temperature, a gap is created between the inner ring 22 and the shaft 14. Even if the rolling element 24 is fixed, rotation can be maintained through relative sliding between the inner ring 22 and the shaft 14. That is, the bearing structure 10 automatically switches to a sliding bearing structure at extremely low temperatures.

[0017] Furthermore, the cooling medium flows in through the groove 30, which can quickly cool the frictional heat generated on the sliding surface, thereby suppressing the temperature rise of the friction surface and reducing the vaporization loss (boiling loss) of cooling media such as liquid hydrogen or liquid nitrogen. Therefore, even in extremely low temperature and unlubricated environments, stable rotational performance can be maintained, improving the reliability and durability of the entire bearing structure 10.

[0018] The bearing structure 10, constructed from the above structure, can perform the following functions.

[0019] It can prevent bearings from becoming stuck due to thermal shrinkage in extremely low temperatures, and can maintain shaft rotation as a sliding bearing even if the rotation of the rolling elements is obstructed.

[0020] The cooling medium flows in through the groove 30, which can efficiently cool the frictional heat and suppress the vaporization loss of the cooling medium.

[0021] Even in extremely low-temperature, unlubricated environments where lubricating oil or grease cannot be used, it ensures stable rotational performance and improves the reliability of devices using cooling media such as liquid hydrogen.

[0022] Therefore, the bearing structure 10 of this invention is extremely useful in mechanical devices operating under extremely low temperature conditions, especially in pumps, compressors, or liquid hydrogen fuel systems that handle liquid hydrogen or liquid nitrogen.

[0023] All documents, patent applications and technical standards mentioned in this specification are deemed to be incorporated herein by reference as if they were described in detail separately.

Claims

1. A bearing structure, characterized in that, include: A shaft; An inner ring fitted around the outer circumference of the shaft; A plurality of rolling elements disposed on the outer periphery of the inner ring, and a bearing component of the outer ring supporting the rolling elements on the outer periphery; And the housing that houses the bearing components; Wherein, a sliding surface that allows relative sliding is formed between the inner circumferential surface of the inner ring and the outer circumferential surface of the shaft; Furthermore, at least one of the inner circumferential surface of the inner ring or the outer circumferential surface of the shaft is formed with a plurality of grooves extending along the axial direction. Cooling medium can flow into the sliding surface through the groove.

Images