Lower housing assembly for a compressor and compressor comprising a lower housing assembly

Abstract

This invention discloses a lower housing assembly for a compressor. The compressor has a cylindrical main housing, wherein the lower housing assembly is installed at the bottom of the main housing. The lower housing assembly includes a first housing and a second housing with the same axis as the main housing. The first housing has a generally recessed shape and a first outer diameter, and is installed on the inner surface of the lower end of the main housing by an interference fit. The second housing has a generally recessed shape and a second inner diameter larger than the first outer diameter. The first housing is tightly embedded in the interior of the second housing and is fixedly connected to the second housing to form a double-layered structure. The second housing is installed on the outer side of the lower end of the main housing. A compressor is also disclosed. This invention, by employing a double-layered structure of an independent lower housing assembly, significantly shifts the first-order axial bending natural frequency of the lower housing assembly upward, avoiding resonance, reducing vibration and noise of the entire machine, and lowering the center of gravity of the entire machine, further reducing vibration and noise.

Description

Technical Field

[0001] This invention belongs to the field of compressor technology, and particularly relates to a lower housing assembly for a compressor and a compressor including the lower housing assembly. Background Technology

[0002] Generally speaking, in existing technologies, the larger the displacement of compressors such as rolling rotor compressors, the stronger the internal aerodynamic and mechanical excitation forces, which leads to a significant increase in the vibration amplitude of the lower casing area of ​​the compressor, making it the main noise radiation surface of the whole machine.

[0003] Furthermore, such as Figure 1 and 2 The schematically illustrated lower housing 1 of a conventional compressor is a single-layer stamped part with a limiting step 2. However, due to manufacturing limitations, the thickness of this single-layer stamped part is limited. Furthermore, the natural frequency of a single-layer stamped lower housing 1 with a thickness of less than 4mm is low, making it prone to resonance coupled with the excitation frequency. During resonance, the vibration amplitude in the lower housing 1 region, especially at the center of the weaker bottom surface, is significantly amplified, thereby radiating strong low-frequency noise, which is harmful to the health of workers.

[0004] In addition, the single-layer lower casing 1 is relatively lightweight, which makes the center of gravity of the compressor relatively high. Under rotational excitation, the whole machine shakes more, which further increases the vibration level of the lower casing 1 and results in greater noise.

[0005] In view of this, there is a need in the art for a new lower housing assembly for a compressor and a compressor including the lower housing assembly, to solve or at least alleviate the disadvantages of the prior art. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the present invention aims to provide a lower housing assembly for a compressor and a compressor including the lower housing assembly. By employing a double-layered stacked structure of an independent lower housing assembly, the natural frequency of the lower housing assembly can be significantly shifted upward without exceeding the single-layer stamping thickness limit, thus fundamentally avoiding resonance. This reduces vibration and noise in the entire compressor. At the same time, by installing the double-layered stacked structure at the bottom of the compressor's main housing, the mass of the compressor's bottom structure is increased, lowering the compressor's center of gravity and reducing the overall vibration transmission gain, further reducing vibration and noise.

[0007] The technical solution according to the present invention is as follows: On one hand, according to an embodiment of the present invention, a lower housing assembly for a compressor is provided, the compressor having a cylindrical main housing, wherein the lower housing assembly is mounted at the bottom of the main housing, and the lower housing assembly includes a first housing and a second housing having the same axis as the main housing, wherein... The first housing has a generally recessed shape and a first outer diameter. The first housing is installed on the inner surface of the lower end of the main housing by an interference fit. The second housing has a generally recessed shape and a second inner diameter that is larger than the first outer diameter. The first housing is tightly embedded inside the second housing, thereby being fixed together with the second housing to form a double-layered structure. The second housing is installed on the outer side of the lower end of the main housing.

[0008] Furthermore, in some embodiments, it is assumed that the inner diameter of the main housing is D_main_in, the outer diameter is D_main_out, and the first outer diameter of the first housing is D_first_out. There is an interference fit δ1 between the first outer diameter of the first housing and the inner diameter of the main housing, wherein the interference fit δ1 = D_first_out - D_main_in, and 0.01mm ≤ δ1 ≤ 0.08mm.

[0009] Furthermore, in some embodiments, the second housing may have a circumferentially extending limiting step near the inner wall of the main housing for abutting the lower end of the main housing.

[0010] Furthermore, in some embodiments, the second housing may have a second maximum inner diameter at the limiting step that is larger than the outer diameter of the main housing. Assuming the second maximum inner diameter of the second housing is D_second_in, The clearance between the second maximum inner diameter and the outer diameter of the main housing is δ2 = D_second_in - D_main_out, where 0.08mm ≤δ2≤0.40mm.

[0011] Furthermore, in some embodiments, the limiting step may have a height H_step, where 2mm ≤ H_step ≤ 8mm.

[0012] Furthermore, in some embodiments, the first housing may have a thickness t1, wherein 2.5 mm ≤ t1 ≤ 5 mm; The second shell may have a thickness t2, where 2mm≤t2≤5mm; The total thickness of the double-layer stacked structure can be T_total = t1 + t2, where 4.5mm≤T_total≤10mm.

[0013] Furthermore, in some embodiments, at the interface between the first housing and the second housing, the first housing and the second housing can be fixed together by circumferential welding, wherein... The double-layer stacked structure may have an axial bending natural frequency f_n, where f_n ≥ 1.3 × f_max, and f_max is the maximum excitation frequency within the rated operating speed range of the compressor; The axial bending natural frequency f_n is determined by the following formula:

[0014] in, t1 is the thickness of the first shell, t2 is the thickness of the second shell, λ is the boundary condition coefficient when the lower shell assembly is simplified to a circular plate, R is the equivalent radius of the lower shell assembly (in meters), E is the elastic modulus of the material (in Pa), α is the welding coefficient of the first shell, β is the welding coefficient of the second shell, and ρ is the material density (in kg / m³). 3 ν is Poisson's ratio.

[0015] For example, the maximum excitation frequency f_max can be 2 times or 4 times the fundamental frequency of the motor's electromagnetic force.

[0016] Preferably, R can be the bottom radius of the lower housing assembly.

[0017] To simplify calculations, the double-layered structure of the lower housing assembly can be simplified to a circular plate. For example, the boundary condition coefficient λ can be the fundamental frequency characteristic value when the periphery of the circular plate is fixed, λ≈3.196.

[0018] Furthermore, in some embodiments, the first housing and the second housing can be fixed together by resistance welding. However, the invention is not limited to this; other welding methods can also be used, such as submerged arc welding, TIG welding, laser welding, plasma arc welding, ultrasonic welding, etc., as long as the first housing and the second housing are firmly fixed together.

[0019] Furthermore, in some embodiments, the first housing and the second housing can be fixed together by continuous circumferential welding. In other embodiments, the first housing and the second housing can be fixed together by circumferential spot welding.

[0020] Preferably, the welding coefficient α of the first shell is 0.9~1.0, and the welding coefficient β of the second shell is 0.06~0.09.

[0021] Furthermore, in some embodiments, the axial bending natural frequency f_n can be 5 to 18% higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the rated operating range of the compressor.

[0022] Furthermore, in some embodiments, a mounting chamfer is provided at the upper end of the first housing.

[0023] On the other hand, according to one embodiment of the present invention, a compressor is provided, which includes the aforementioned lower housing assembly for the compressor.

[0024] Specifically, the compressor is a rolling rotor compressor.

[0025] The lower housing assembly for a compressor and the compressor including the lower housing assembly according to the embodiments of this application can achieve the following beneficial effects: 1) This invention can significantly improve the equivalent stiffness of the lower housing assembly by adopting a double-layer stacked structure of an independent lower housing component without exceeding the single-layer stamping thickness limit. Its bending stiffness and in-plane stiffness are greatly improved, so that the first-order axial bending natural frequency of the lower housing assembly is offset from the resonant frequency and significantly shifted upward. This natural frequency can be higher than the main excitation frequency range of the compressor, thus avoiding resonance from the root. This reduces the vibration and noise of the compressor as a whole. At the same time, by installing the double-layer stacked structure at the bottom of the compressor main housing, the mass of the compressor bottom structure is increased, the center of gravity of the compressor is lowered, the vibration transmission gain of the whole machine is reduced, and the vibration amplitude of the lower housing assembly is significantly reduced, further reducing the vibration and noise of the compressor. 2) The present invention can precisely limit the axial depth of the main housing inserted into the second housing by providing a limiting step on the inner wall of the second housing, thereby precisely controlling the relative position of the lower housing assembly relative to the compressor main housing, including the axial position and radial position of the lower housing assembly relative to the compressor main housing, etc. 3) The present invention can fix the first and second shells of the lower shell assembly together by welding to form a whole, which makes the structural integrity of the lower shell assembly better, the vibration transmission attenuation effect improved, and the overall noise level of the machine further reduced; 4) The present invention can design the first housing and the second housing to have specific thicknesses, so that the axial bending natural frequency f_n is 5~18% higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the rated operating range of the compressor, thereby significantly reducing the vibration and noise of the compressor. Attached Figure Description

[0026] The features, advantages, and exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals indicate the same elements, wherein: Figure 1 A perspective view of a single-layer stamped lower housing in the prior art is schematically shown; Figure 2 schematically shown Figure 1 Front view and AA section view of the single-layer stamped lower shell; Figure 3A schematic diagram of a lower housing assembly for a compressor according to an embodiment of the present invention is shown in partial cross-sectional view; Figure 4 schematically shown Figure 3 Enlarged detail of the lower housing assembly.

[0027] Component Symbol List 1: Single-layer stamped lower shell; 2: Limiting step; 100: Lower housing assembly; 110: First housing; 111: Mounting chamfer; 120: Second housing; 121: Limiting step; 130: Interface; 200: Main housing; 300: Upper housing; Dispenser 400; D_main_in: Inner diameter; D_main_out: Outer diameter; D_first_out: First outer diameter; D_second_in: Second maximum inner diameter; δ1: Interference fit amount; δ2: Gap amount; H_step: Height; t1: First shell thickness; t2: Second shell thickness; T_total: Total thickness; t: Equivalent shell thickness of the lower shell assembly; f_n: Axial bending natural frequency; f_max: The maximum excitation frequency within the rated operating speed range of the compressor; R: Equivalent radius of the lower housing assembly; E: Material elastic modulus; ρ: Material density; λ: Boundary condition coefficient; ν: Poisson's ratio; α: Welding coefficient of the first shell; β: Welding coefficient of the second shell. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments according to this invention. The description of exemplary embodiments is for illustrative purposes only and is by no means a limitation on this invention or its applications or uses. Furthermore, the dimensions and proportions of the components in the figures are merely schematic and do not strictly correspond to actual products.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a reference structure" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0030] It should be noted that many of the terms used herein are relative terms. For example, the terms “upper” and “lower” are relative to each other, meaning that the upper component is located at a higher height than the lower component, and should not be construed as requiring a particular orientation or position of the structure. As a further embodiment, the terms “inner,” “outer,” “bottom,” “inward,” and “outward” are relative to the center and should not be construed as requiring a specific orientation or position of the structure.

[0031] It is emphasized here that, unless otherwise stated, the terminology used herein is consistent with the common meaning of various scientific and technical terms in this field, as well as the meaning of professional terms defined in various technical dictionaries, textbooks, etc.

[0032] For example, in this paper, the term "axial bending natural frequency f_n" can refer to the natural frequency corresponding to the bending vibration of the bottom surface of the lower shell in the plane containing its axis, wherein the axis of the lower shell is perpendicular to the bottom surface of the lower shell. In particular, in this paper, the term "axial bending natural frequency f_n" can specifically refer to "first-order axial bending natural frequency f_n".

[0033] R represents the equivalent radius of the lower shell assembly. This equivalent radius can be understood as using the radius of an ideal lower shell to represent the radius of the lower shell assembly. In this case, it can be simplified to the average of the sum of the mid-surface radii of the inner and outer lower shells. For simplified calculation, the mid-surface radius can be determined as half the sum of the inner diameter radius and wall thickness of the corresponding lower shell. In this paper, the inner lower shell can be considered the first shell, and the outer lower shell can be considered the second shell.

[0034] In this paper, the term "boundary condition coefficient" can be understood as a constant that affects the natural frequency of a component, determined by the installation and fixing method. Generally speaking, the larger the value, the stronger the constraint and the higher the natural frequency; the smaller the value, the weaker the constraint and the lower the natural frequency. In this paper, the term "boundary condition coefficient λ" can refer to the boundary condition coefficient when the lower shell assembly is simplified to a circular plate.

[0035] In existing technologies, single-layer stamped parts are fixed at the edges by interference fits and circumferential welding, resulting in relatively simple constraints and low natural frequencies. In contrast, in the double-layer stacked structure according to the present invention, the second shell not only has increased thickness, but its inner wall steps tightly abut against the main shell, and there is welding between the main shell and the second shell. This is equivalent to adding double radial support and axial constraint to the edge of the lower shell assembly. Therefore, the boundary condition coefficient of the double-layer stacked structure according to the present invention has a significant potential for improvement compared to the traditional single-layer structure under actual working conditions, with stronger constraints and larger coefficients, which further contributes to the increase of the natural frequency.

[0036] In this invention, under the condition that the lower housing assembly can be simplified to a circular plate structure, the boundary condition coefficient λ can be selected as the fundamental frequency characteristic value when the periphery of the circular plate is fixed, at which time λ≈3.196.

[0037] The term "welding coefficient," also known as "weld joint strength coefficient," refers to the ratio of the strength of a butt weld joint to the strength of the base material.

[0038] In this article, the term "maximum excitation frequency f_max within the rated operating range of the compressor" can refer to twice the exhaust pulsating excitation frequency corresponding to the highest rated rotor frequency. For example, when the exhaust pulsating excitation frequency is 120Hz, the aforementioned maximum excitation frequency f_max can be 2 × 120Hz = 240Hz.

[0039] In this document, the term "fundamental frequency" specifically refers to the lowest natural frequency of the lower housing assembly in the axial bending vibration mode. This fundamental frequency is the frequency point at which the housing structure is most sensitive to external dynamic excitation and exhibits the largest vibration response amplitude. This application, by setting a double-layered stacked structure, aims to offset and significantly enhance the lowest natural frequency of the lower housing assembly from the resonant frequency, making it higher than the main electromagnetic excitation frequency within the compressor's operating range, thereby avoiding resonance at the frequency point most prone to severe vibration.

[0040] The term "equivalent stiffness of the lower shell assembly" can be understood as using the stiffness of an ideal lower shell to equivalently represent the stiffness of a lower shell assembly.

[0041] The term "in-plane stiffness" refers to the ability of a lower housing assembly to resist deformation along the tangent of its own surface.

[0042] Please note that all ranges disclosed herein include the endpoints and can be combined independently. For example, the range “0.06~0.09” includes the endpoints 0.06 and 0.09, as well as all intermediate values.

[0043] This application addresses the problem of large vibration amplitude and easy resonance noise in the lower casing of compressors such as rolling rotor compressors. By providing a lower casing assembly with a double-layer stacked structure and installing the lower casing assembly at the bottom of the compressor's main casing, the rigidity of the casing, natural frequency, and overall center of gravity distribution are optimized, thereby controlling or reducing the vibration and radiated noise during compressor operation.

[0044] The following description, with reference to the accompanying drawings, illustrates an embodiment of the present invention, including a lower housing assembly for a compressor and a compressor comprising the lower housing assembly.

[0045] On the one hand, according to an embodiment of this application, such as Figure 3 and 4 As shown, a lower housing assembly 100 for a compressor is provided, the compressor having a cylindrical main housing 200, wherein the lower housing assembly 100 is mounted at the bottom of the main housing 200, and the lower housing assembly 100 includes a first housing 110 and a second housing 120 having the same axis as the main housing 200, wherein... The first housing 110 has a generally recessed shape and a first outer diameter. The first housing 110 is installed on the inner surface of the lower end of the main housing 200 by an interference fit. The second housing 120 has a generally recessed shape and a second inner diameter that is larger than the first outer diameter. The first housing 110 is tightly embedded inside the second housing 120, thereby being fixed together with the second housing 120 to form a double-layered structure. The second housing 120 is installed on the outer side of the lower end of the main housing 200.

[0046] As described above, the first housing 110 and the second housing 120 may have the same axis as the cylindrical main housing 200, which may be the central axis of the cylindrical main housing 200 located in the center of the cylindrical body and perpendicular to the bottom surface of the main housing 200.

[0047] Preferably, the lower housing assembly 100 may be a centrally symmetrical structure symmetrical about the central axis.

[0048] like Figure 3 and 4 As shown, the bottom of the first housing 110 may be a generally flat, disc-shaped structure with generally trapezoidal sides, or other structures, as needed. Furthermore, a counterweight of appropriate weight may be provided on the inner side of the bottom of the first housing 110 to further lower the overall center of gravity of the compressor and counteract the imbalance of centrifugal force during rotation, thereby further reducing vibration and noise.

[0049] like Figure 3 and 4 As shown, the bottom of the second housing 120 may be a generally flat, disc-shaped structure with generally trapezoidal sides, or other structures, as needed. Furthermore, a counterweight of appropriate weight may be provided on the outer side of the bottom of the second housing 120 to further lower the overall center of gravity of the compressor and counteract the imbalance of centrifugal force during rotation, thereby further reducing vibration and noise.

[0050] Furthermore, in some embodiments, it is assumed that the inner diameter of the main housing 200 is D_main_in, the outer diameter is D_main_out, and the first outer diameter of the first housing 110 is D_first_out. There is an interference fit δ1 between the first outer diameter of the first housing 110 and the inner diameter of the main housing 200. This interference fit δ1 = D_first_out - D_main_in, where 0.01mm ≤ δ1 ≤ 0.08mm. When the interference fit δ1 is less than 0.01mm, the interference is too small, and the lower housing assembly can easily loosen; when the interference fit δ1 is greater than 0.08mm, the lower housing assembly is difficult to assemble into the cylindrical main housing of the compressor.

[0051] Furthermore, in some embodiments, the second housing 120 may have a circumferentially extending limiting step 121 near the inner wall of the main housing 200, which abuts against the lower end of the main housing 200 to limit the axial depth of the main housing 200 inserted into the second housing 120. With the aid of the limiting step, the relative position of the lower housing assembly with respect to the compressor main housing can be precisely controlled, including the axial and radial positions of the lower housing assembly relative to the compressor main housing.

[0052] Furthermore, in some embodiments, the second housing 120 may have a second maximum inner diameter at the limiting step 121 that is greater than the outer diameter of the main housing 200. Assuming the second maximum inner diameter of the second housing 120 is D_second_in, the gap between the second maximum inner diameter and the outer diameter of the main housing 200 is δ2 = D_second_in - D_main_out, where 0.08mm ≤δ2≤0.40mm.

[0053] Furthermore, in some embodiments, the aforementioned limiting step 121 may have a height H_step, where 2mm ≤ H_step ≤ 8mm. When H is less than 2mm, the limiting step 121 is too short, making it difficult to fix the main housing 200 to the second housing 120, resulting in instability and lack of effective guidance; when H is greater than 8mm, the limiting step 121 is too high, wasting material.

[0054] Furthermore, in some embodiments, the first housing 110 may have a thickness t1, wherein 2.5mm≤t1≤5mm; the second housing 120 may have a thickness t2, wherein 2mm≤t2≤5mm; the total thickness T_total of the double-layered structure may be t1 + t2, wherein 4.5mm≤T_total≤10mm.

[0055] When the thickness t1 of the first housing 110 is less than 2.5 mm, the first housing 110 is too thin, the natural frequency of the lower housing assembly is low, and it is easy to resonate with the whole compressor; when the thickness t1 of the first housing 110 is greater than 5 mm, the compressor pressing is limited or more difficult.

[0056] Furthermore, in some embodiments, at the interface 130 between the first housing 110 and the second housing 120, the first housing 110 and the second housing 120 can be fixed together by circumferential welding, wherein... The double-layer stacked structure may have an axial bending natural frequency f_n, where f_n ≥ 1.3 × f_max, and f_max is the maximum excitation frequency within the rated operating speed range of the compressor; The axial bending natural frequency f_n is determined by the following formula:

[0057] Where t1 is the thickness of the first shell, t2 is the thickness of the second shell, λ is the boundary condition coefficient when the lower shell assembly is simplified to a circular plate, R is the equivalent radius of the lower shell assembly (in meters), E is the elastic modulus of the material (in Pa), α is the welding coefficient of the first shell, β is the welding coefficient of the second shell, and ρ is the material density (in kg / m³). 3 ν is Poisson's ratio.

[0058] For example, the maximum excitation frequency f_max can be 2 times or 4 times the fundamental frequency of the motor's electromagnetic force.

[0059] Preferably, R can be the bottom radius of the lower housing assembly.

[0060] For example, the boundary condition coefficient λ can be the fundamental frequency characteristic value when the periphery of the circular plate is fixed, λ≈3.196.

[0061] Preferably, the first housing 110 and the second housing 120 can be fixed together by circumferential resistance welding. However, the present invention is not limited to this, and other welding methods can also be used, such as submerged arc welding, TIG welding and other electric arc welding, laser welding, plasma arc welding, ultrasonic welding, etc., as long as the first housing and the second housing are firmly fixed together.

[0062] Furthermore, in some embodiments, the first housing 110 and the second housing 120 can be fixed together by continuous circumferential welding. In other embodiments, the first housing 110 and the second housing 120 can be fixed together by circumferential spot welding.

[0063] Preferably, the welding coefficient α of the first shell is 0.9 to 1.0, and the welding coefficient β of the second shell is 0.06 to 0.09. For example, the welding coefficient α of the first shell can be 0.95, 0.98, etc., and the welding coefficient β of the second shell can be 0.06, 0.07, 0.08, etc.

[0064] Furthermore, in some embodiments, the axial bending natural frequency f_n can be 5 to 18% higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the rated operating range of the compressor, for example, 7%, 10%, 12%, 14%, 16%, 18%, etc.

[0065] Furthermore, in some embodiments, a mounting chamfer 111 may be provided at the upper end of the first housing 110 to facilitate the guiding of the first housing 110 into the main housing 200. For example, the mounting chamfer 111 may be a rounded corner or a beveled corner.

[0066] The following simulation experiments illustrate the comparison between the axial bending natural frequency f_n_a of the double-layer stacked structure of the present invention and the axial bending natural frequency f_n_b of the single-layer lower shell of the prior art, as well as the comparison with the maximum excitation frequency f_max within the rated operating speed range of the compressor.

[0067] Table 1 compares the axial bending natural frequency f_n_a of the double-layer stacked structure of the present invention with the axial bending natural frequency f_n_b of the single-layer lower shell in the prior art, and with the maximum excitation frequency f_max within the rated operating speed range of the compressor.

[0068]

[0069] Table 1 shows four sets of data. In Table 1, the compressor frequency can be set to 90Hz, and the maximum excitation frequency f_max within the compressor's rated operating speed range is 4500Hz. As a comparative example, when the thickness of the single-layer lower housing is 3.2mm, its axial bending natural frequency f_n_b can be 4538Hz. However, the bending natural frequency f_n_a of the corresponding double-layer stacked structure according to the embodiment of the present invention is significantly higher. For example, correspondingly, when the thickness of the first housing 110 is 3.2mm and the thickness of the second housing 120 is 3.2mm, the bending natural frequency f_n_a of the double-layer stacked structure can be 4815Hz, which is 7% higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the compressor's rated operating range. As another example, when the thickness of the first housing 110 is 3.2mm and the thickness of the second housing 120 is 4.0mm, the bending natural frequency f_n_a of the double-layer stacked structure can be 5036Hz, which is 12% higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the compressor's rated operating range. For example, when the thickness of the first housing 110 is 3.2 mm and the thickness of the second housing 120 is 4.5 mm, the bending natural frequency f_n_a of the double-layered structure can be 5127 Hz, which is higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the rated operating range of the compressor by 14%. For another example, when the thickness of the first housing 110 is 3.2 mm and the thickness of the second housing 120 is 5.0 mm, the bending natural frequency f_n_a of the double-layered structure can be 5213 Hz, which is higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the rated operating range of the compressor by 16%.

[0070] Table 2 shows some examples of the bending natural frequencies f_n_a of the double-layer stacked structure according to embodiments of the present invention.

[0071] For example, as shown in Table 2, in the double-layered structure of some embodiments of the present invention, both the first shell 110 and the second shell 120 can be made of steel, wherein the elastic modulus of the material is E=206*10^9 Pa and the material density is ρ=7850kg / mm³. 3 Poisson's ratio ν = 0.3, the welding coefficient α of the first shell 110 is 1.0, and the welding coefficient β of the second shell is 0.06~0.09. When the double-layered structure is simplified to a circular plate, λ≈3.196.

[0072] Referring to Group 1, when the thickness of the first shell is t1=2.5mm, the thickness of the second shell is t2=2mm, the total thickness of the double-layered structure is T_total = t1 + t2=4.5mm, the equivalent radius of the lower shell assembly is R=0.05m, and the welding coefficient of the second shell is β=0.06, the bending natural frequency of the double-layered structure is f_n_a=3724 Hz.

[0073] Referring to Group 3, when the thickness of the first shell is t1=3.2mm, the thickness of the second shell is t2=4.0mm, the total thickness of the double-layered structure is T_total = t1 + t2=7.2mm, the equivalent radius of the lower shell assembly is R=0.05m, and the welding coefficient of the second shell is β=0.07, the bending natural frequency of the double-layered structure is f_n_a=4946 Hz.

[0074] Referring to Group 7, when the thickness of the first shell is t1=5mm, the thickness of the second shell is t2=5mm, the total thickness of the double-layered structure is T_total = t1 + t2=10mm, the equivalent radius of the lower shell assembly is R=0.05m, and the welding coefficient of the second shell is β=0.09, the bending natural frequency of the double-layered structure is f_n_a=7746 Hz.

[0075] Table 2 shows the bending natural frequencies f_n_a of the double-layered stacked structure in the embodiments of the present invention.

[0076] On the other hand, according to one embodiment of the present invention, a compressor is provided, which includes the aforementioned lower housing assembly 100 for the compressor.

[0077] Specifically, the compressor is a rolling rotor compressor. However, the invention is not limited to this; the compressor may also include a rotary vane compressor, etc.

[0078] This invention can be applied to rolling rotor compressors, but it is not limited thereto. Figure 3 An example application of the present invention is shown.

[0079] Figure 3 The illustrated rotary compressor may include a main housing 200, an upper housing 300, a lower housing assembly 100, and a distributor 400. By employing the lower housing assembly 100, the aforementioned rotary compressor can significantly reduce vibration and noise.

[0080] In summary, this invention, by employing a double-layered structure of an independent lower housing assembly, significantly improves the equivalent stiffness of the lower housing assembly without exceeding the single-layer stamping thickness limit. Its bending stiffness and in-plane stiffness are greatly enhanced, causing the first-order axial bending natural frequency of the lower housing assembly to be offset from the resonant frequency and significantly shifted upwards. This natural frequency is higher than the compressor's main excitation frequency range, fundamentally avoiding resonance. This reduces overall compressor vibration and noise. Furthermore, by installing the double-layered structure at the bottom of the compressor's main housing, the mass of the compressor's bottom structure is increased, lowering the compressor's center of gravity and reducing overall vibration transmission gain. The vibration amplitude of the lower housing assembly is significantly reduced, further decreasing compressor vibration and noise.

[0081] Furthermore, by providing a limiting step on the inner wall of the second housing, the present invention can precisely limit the axial depth of the main housing inserted into the second housing, thereby precisely controlling the relative position of the lower housing assembly relative to the compressor main housing, including the axial and radial positions of the lower housing assembly relative to the compressor main housing.

[0082] Furthermore, the present invention can weld the first and second housings of the lower housing assembly together to form a whole, thereby improving the structural integrity of the lower housing assembly, enhancing the vibration transmission attenuation effect, and further reducing the overall noise level of the machine.

[0083] Finally, by designing the first and second housings to have specific thicknesses, the present invention makes the axial bending natural frequency f_n 5~18% higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the rated operating range of the compressor, thereby significantly reducing the vibration and noise of the compressor.

[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lower housing assembly for a compressor, the compressor having a cylindrical main housing, characterized in that, The lower housing assembly is mounted at the bottom of the main housing, and the lower housing assembly includes a first housing and a second housing having the same axis as the main housing, wherein... The first housing has a generally recessed shape and a first outer diameter. The first housing is installed on the inner surface of the lower end of the main housing by an interference fit. The second housing has a generally recessed shape and a second inner diameter that is larger than the first outer diameter. The first housing is tightly embedded inside the second housing, thereby being fixed together with the second housing to form a double-layered structure. The second housing is installed on the outer side of the lower end of the main housing.

2. The lower housing assembly as claimed in claim 1, characterized in that, Assume the inner diameter of the main housing is D_main_in, the outer diameter is D_main_out, and the first outer diameter of the first housing is D_first_out. There is an interference fit δ1 between the first outer diameter of the first housing and the inner diameter of the main housing, wherein the interference fit δ1 = D_first_out - D_main_in, and 0.01mm≤δ1≤0.08mm.

3. The lower housing assembly as described in claim 2, characterized in that, The second housing has a circumferentially extending limiting step near the inner wall of the main housing, which is used to abut the lower end of the main housing.

4. The lower housing assembly as claimed in claim 3, characterized in that, in, The second housing has a second maximum inner diameter at the limiting step that is larger than the outer diameter of the main housing. Assume that the second maximum inner diameter of the second housing is D_second_in. The clearance between the second maximum inner diameter and the outer diameter of the main housing is δ2 = D_second_in - D_main_out, where 0.08mm≤δ2≤0.40mm.

5. The lower housing assembly as claimed in claim 4, characterized in that, The limiting step has a height H_step, where 2mm ≤H_step ≤ 8mm.

6. The lower housing assembly as claimed in claim 5, characterized in that, The first shell has a thickness t1, where 2.5mm≤t1≤5mm; The second shell has a thickness t2, where 2mm≤t2≤5mm; The total thickness of the double-layered structure is T_total = t1 + t2, where 4.5mm ≤ T_total ≤ 10mm.

7. The lower housing assembly as claimed in claim 1 or 6, characterized in that, At the interface between the first housing and the second housing, the first housing and the second housing are fixed together by circumferential welding, wherein, The double-layered structure has an axial bending natural frequency f_n, where f_n ≥ 1.3 × f_max, and f_max is the maximum excitation frequency within the rated operating speed range of the compressor; The axial bending natural frequency f_n is determined by the following formula: in, t1 is the thickness of the first shell, t2 is the thickness of the second shell, λ is the boundary condition coefficient when the lower shell assembly is simplified to a circular plate, R is the equivalent radius of the lower shell assembly, E is the elastic modulus of the material, α is the welding coefficient of the first shell, β is the welding coefficient of the second shell, ρ is the material density, and ν is Poisson's ratio.

8. The lower housing assembly as claimed in claim 7, characterized in that, α＝0.9~1.0，β=0.06~0.09。 9. The lower housing assembly as claimed in claim 7, characterized in that, The axial bending natural frequency f_n is 5~18% higher than the main harmonic frequency corresponding to the maximum excitation frequency f_max within the rated operating range of the compressor.

10. A compressor, characterized in that, Includes a lower housing assembly for a compressor as described in any one of claims 1 to 9, particularly, the compressor being a rolling rotor compressor.

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