Scroll wrap with trapezoidal section and design method thereof

Abstract

The scroll wrap comprises a movable scroll wrap and a static scroll wrap which are completely identical in shape, the tooth thickness of the movable scroll wrap and the tooth thickness of the static scroll wrap are linearly decreased from the tooth root to the tooth top in the axis direction, a trapezoidal section is formed in the direction parallel to the axis, and through collaborative design of a draft angle beta and a draft regulation factor gamma, the draft angle beta and the draft regulation factor gamma are matched with each other. Inclination difference of the inner wall and the outer wall is dynamically adjusted, and interference-free meshing of the movable scroll wrap and the static scroll wrap in revolution and translation is ensured. The design method comprises the following steps: establishing a tooth root molded line based on a given initial parameter; calculating a draft angle beta; dynamically adjusting the inclination angle difference of the inner and outer walls through the gamma value; calculating a molded line equation at any axial height; and rotating the movable scroll wrap molded line by 180 degrees to obtain a static scroll wrap molded line. According to the scroll wrap with the trapezoidal cross section of the scroll compressor, the weight of the tooth crest is reduced while the strength of the tooth root is improved, the stress state of the scroll wrap is improved, and the dynamic characteristic is good; the volume utilization efficiency is optimized, the internal volume ratio is large, the number of turns is small, and the leakage line length is short.

Description

Technical Field

[0001] This invention belongs to the field of compressor engineering technology, and specifically relates to a trapezoidal cross-section scroll tooth of a scroll compressor. Background Technology

[0002] A scroll compressor is a positive displacement fluid machine. During operation, the moving scroll revolves and translates, and the moving and stationary scroll teeth mesh to form several pairs of periodically changing crescent-shaped working chambers. As the crankshaft rotates continuously, the process of gas intake, compression, and discharge is completed. Due to its simple structure, few parts, smooth operation, low noise, and high reliability, it is widely used in air conditioning, refrigeration, medical equipment, and vacuum systems. The profile of the scroll teeth directly affects the performance of the scroll compressor; therefore, the design of the scroll tooth profile is extremely critical.

[0003] When a scroll compressor requires a high compression ratio, a larger number of scroll teeth are needed, which increases the overall size of the compressor and the length of the leakage line, thus exacerbating leakage. Chinese Patent (Wang Jun, Cao Chenyan, Cui Shujie, Wei Shuhong, Yang Shuran, Zhao Feng. A Fully Meshing Variable Wall Thickness Scroll Vacuum Pump [P]. Shandong: CN107939681A, 2018-04-20.) discloses a fully meshing variable wall thickness scroll vacuum pump. Its scroll tooth profile consists of circular involutes and high-order continuous curves. Compared to a constant cross-section scroll tooth of the same size, this increases the compressor's compression ratio and reduces the length of the scroll tooth profile and leakage. However, the profile composition is complex, and the moving scroll teeth have a large tooth thickness, resulting in a large mass and high rotational inertia force, thus reducing its dynamic characteristics. Summary of the Invention

[0004] To address the issues of high compression ratio requirements, numerous wheel turns, long leakage lines, low strength of existing scroll teeth, and poor dynamic characteristics due to the large mass of moving scroll teeth, this invention proposes a trapezoidal cross-section scroll tooth and its design method. This scroll tooth employs identical moving and stationary scroll tooth structures, with their tooth thickness decreasing linearly from the tooth root to the tooth tip along the axial direction to form a continuous trapezoidal cross-section. By coordinating the draft angle β and the adjustment factor γ to control the inclination of the inner and outer walls, correct meshing can be achieved. The trapezoidal cross-section structure effectively enhances the tooth root strength and enables a lightweight design for the moving scroll, resulting in smoother operation and superior dynamic characteristics. This is of great significance for improving the efficiency and reliability of scroll machinery.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A trapezoidal cross-section vortex tooth includes: a moving vortex tooth (1) and a stationary vortex tooth (2);

[0007] The tooth thickness of the moving volute tooth (1) decreases linearly from the tooth root to the tooth tip along the axial direction, forming a continuous trapezoidal section in the cross-section parallel to the axial direction; the angle formed between the inner wall of the moving volute tooth (1) and the axial direction is the inner wall draft angle β1, the expression of which is: The angle formed between the outer wall of the moving vortex tooth (1) and the axial direction is the outer wall draft angle β2, and its expression is:

[0008] Where γ is the draft adjustment factor, γ∈[-1,1]; T1 is the wall thickness at the tip of the moving scroll tooth, T2 is the wall thickness at the root of the moving scroll tooth, and H is the height of the moving scroll tooth.

[0009] The asymmetric inclination of the inner and outer walls of the moving vortex tooth is achieved by γ. When γ = 0, the inner wall draft angle is equal to the outer wall draft angle, forming a symmetrical isosceles trapezoidal cross section. When γ ≠ 0, the inner wall draft angle β(1+γ) is not equal to the outer wall draft angle β(1-γ), forming an asymmetric trapezoidal cross section.

[0010] The variation law of tooth thickness T along the axial height z of the moving vortex tooth (1) is as follows:

[0011]

[0012] in, Let be the involute development angle, z be the axial height, and z∈[0,H];

[0013] The moving vortex tooth (1) and the stationary vortex tooth (2) are completely identical. After the moving vortex tooth (1) is rotated 180° relative to the center point O, it completely overlaps with the stationary vortex tooth (2).

[0014] During its revolution and translation, the moving scroll tooth (1) can achieve correct meshing with the stationary scroll tooth (2). The expression for the radius of rotation of the moving scroll tooth is:

[0015] R or =R b π-[T2-H(tanβ1+tanβ2)] / 2.

[0016] A design method for trapezoidal cross-section spiral teeth, characterized by the following steps:

[0017] 1) Establish a two-dimensional coordinate system with the center point O of the vortex tooth as the origin, and give the following constants: base circle radius R b Initial phase angle α, tooth height H of moving vortex tooth (1), tooth tip wall thickness T1 of moving vortex tooth (1), tooth root wall thickness T2 of moving vortex tooth (1), draft adjustment factor γ;

[0018] 2) Generate the basic profile at the root of the moving spiral tooth (1) (z=0), that is, the profiles of the inner and outer walls at the root of the moving spiral tooth (1):

[0019] The equation for the inner wall profile of the moving vortex tooth (1) is:

[0020]

[0021] The equation of the outer wall profile of the moving vortex tooth (1) is:

[0022]

[0023] Among them, R b The radius of the base circle; α is the involute development angle; α is the initial phase angle.

[0024] 3) Calculate the draft parameters: Based on the root end wall thickness T2, the tip wall thickness T1, the height H, and the draft adjustment factor γ of the moving scroll tooth (1), calculate the draft angles of the inner and outer walls of the moving scroll tooth (1):

[0025] The expression for the inner wall draft angle β1 of the moving vortex tooth (1) is:

[0026] The draft angle β2 of the outer wall of the moving vortex tooth (1) is expressed as follows:

[0027] Wherein, γ is the draft adjustment factor, γ∈[-1,1], and the asymmetric inclination of the inner and outer walls is achieved through γ; T1 is the wall thickness at the top of the moving volute tooth (1), T2 is the wall thickness at the root of the moving volute tooth (1), and H is the tooth height of the moving volute tooth (1).

[0028] 4) Perform draft treatment on the basic profile at the root of the moving volute tooth (1) to generate a trapezoidal cross-section volute tooth:

[0029] Combined with the draft angle parameters, the basic profile at the tooth root is drafted along the axial direction to generate the inner and outer profiles of the moving vortex tooth (1) at any axial height z.

[0030] The equation of the inner wall profile of the moving vortex tooth (1) at any axial height z is:

[0031]

[0032] The equation of the outer wall profile of the moving vortex tooth (1) at any axial height z is:

[0033]

[0034] Among them, R b The radius of the base circle; α is the involute development angle; z is the initial phase angle; β is the axial height, z∈[0,H]; γ is the draft angle; γ is the draft adjustment factor, γ∈[-1,1];

[0035] 5) Generate the profile of the stationary vortex tooth (2): Rotate the profile of the moving vortex tooth (1) 180° relative to the center point O to obtain the inner and outer profiles of the stationary vortex tooth (2):

[0036] The equation for the inner wall profile of the static vortex tooth (2) is:

[0037]

[0038] The equation for the outer wall profile of the static vortex gear (2) is:

[0039]

[0040] The beneficial effects of this invention are as follows:

[0041] ① The proposed trapezoidal cross-section vortex tooth improves the bending strength and fatigue resistance of the tooth root region. At the same time, the reduction of the tooth tip thickness reduces the inertial mass of the rotating component and improves the dynamic balance characteristics of the moving vortex tooth, thus significantly reducing its vibration and noise levels during high-speed operation.

[0042] ② The proposed trapezoidal cross-section vortex tooth effectively shortens the leakage path between adjacent compression chambers. Combined with the tight fit design between the tooth tip and the substrate, it significantly reduces the amount of gas leakage through the meshing gap, thereby improving the volumetric efficiency and sealing performance of the compression process.

[0043] ③ The proposed trapezoidal cross-section vortex tooth reduces the number of compression cycles and simplifies the gas compression path, reduces friction loss and energy waste, improves the internal volume ratio, and significantly improves the overall energy efficiency ratio. Attached Figure Description

[0044] Figure 1 This is a three-dimensional structural diagram of a trapezoidal cross-section vortex tooth.

[0045] Figure 2 This is a schematic diagram of a three-dimensional cross-section of a trapezoidal vortex tooth.

[0046] Figure 3 This is a two-dimensional schematic diagram of a trapezoidal cross-section spiral tooth.

[0047] Figure 4 The diagram shows the moving vortex tooth (1) and the stationary vortex tooth (2) at the center of revolution.

[0048] Figure 5 Figure 1 shows the moving vortex gear.

[0049] Figure 6 Figure 2 shows the static vortex spiral gear.

[0050] Figure 7 , 8 Figures 9 and 10 show the meshing process of the moving vortex tooth (1) and the stationary vortex tooth (2).

[0051] Figure 11 , 12 Figures 1 and 13 are two-dimensional cross-sectional views of the moving vortex tooth (1) and the stationary vortex tooth (2) at different heights along the axial direction.

[0052] In the diagram: 1—moving vortex tooth; 2—stationary vortex tooth. Detailed Implementation

[0053] The invention will now be further described with reference to the accompanying drawings.

[0054] like Figure 1 The figure shows a three-dimensional structure diagram of a trapezoidal cross-section vortex tooth, including a moving vortex tooth (1) and a stationary vortex tooth (2). The moving vortex tooth (1) and the stationary vortex tooth (2) are completely identical. The moving vortex tooth (1) rotates 180° relative to the center point O and then completely overlaps with the stationary vortex tooth (2).

[0055] like Figure 2 As shown, this is a schematic diagram of a three-dimensional cross-section of a trapezoidal vortex tooth. The tooth thickness of the moving vortex tooth (1) and the stationary vortex tooth (2) decreases linearly from the tooth root to the tooth tip along the axial direction, forming a continuous trapezoidal cross-section in the cross-section parallel to the axial direction.

[0056] like Figure 3 The figure shows a two-dimensional schematic diagram of a trapezoidal cross-section vortex tooth. The angle formed between the inner wall of the moving vortex tooth (1) and the axial direction is the inner wall draft angle β1, and its expression is: The angle formed between the outer wall of the moving vortex tooth (1) and the axial direction is the outer wall draft angle β2, and its expression is:

[0057] Where γ is the draft adjustment factor, γ∈[-1,1]; T1 is the wall thickness at the tip of the moving scroll tooth, T2 is the wall thickness at the root of the moving scroll tooth, and H is the height of the moving scroll tooth.

[0058] The asymmetric inclination of the inner and outer walls of the moving vortex tooth is achieved by γ. When γ = 0, the inner wall draft angle is equal to the outer wall draft angle, forming a symmetrical isosceles trapezoidal cross section. When γ ≠ 0, the inner wall draft angle β(1+γ) is not equal to the outer wall draft angle β(1-γ), forming an asymmetric trapezoidal cross section.

[0059] like Figure 4 As shown, the diagram shows the moving vortex tooth (1) and the stationary vortex tooth (2) at the center of revolution. The moving vortex tooth (1) and the stationary vortex tooth (2) are completely identical. After the moving vortex tooth (1) rotates 180° relative to the center point O, it completely coincides with the stationary vortex tooth (2).

[0060] like Figure 5 The figure shown is a diagram of the moving vortex tooth (1). The equation of the inner wall profile of the moving vortex tooth (1) at any axial height z is:

[0061]

[0062] The equation of the outer wall profile of the moving vortex tooth (1) at any axial height z is:

[0063]

[0064] Among them, R b The radius of the base circle; α is the involute development angle; z is the initial phase angle; β is the axial height, z∈[0,H]; γ is the draft angle; γ is the draft adjustment factor, γ∈[-1,1].

[0065] like Figure 6 The figure shown is of the static vortex tooth (2). The equation of the inner wall profile of the static vortex tooth (2) is:

[0066]

[0067] The equation for the outer wall profile of the static vortex gear (2) is:

[0068]

[0069] like Figure 7 , 8 As shown in Figures 9 and 10, the meshing process of the moving vortex tooth (1) and the stationary vortex tooth (2) is shown. During the working process of the revolution and translation, the moving vortex tooth (1) can achieve correct meshing with the stationary vortex tooth (2), that is, the inner wall and outer wall of the moving vortex tooth (1) can achieve correct meshing with the outer wall and inner wall of the stationary vortex tooth (2), respectively. Figure 7 , 8 9 and 10 represent the crankshaft rotation angles of 0°, 90°, 180°, and 270° respectively during the meshing process of the moving scroll tooth (1) and the stationary scroll tooth (2). The expression for the rotation radius of the moving scroll tooth is:

[0070] R or =R b π-[T2-H(tanβ1+tanβ2)] / 2.

[0071] like Figure 11 , 12 As shown in Figure 13, these are two-dimensional cross-sectional views of the moving vortex tooth (1) and the stationary vortex tooth (2) at different heights along the axial direction. The variation law of the tooth thickness of the moving vortex tooth (1) and the stationary vortex tooth (2) along the axial height z is as follows:

[0072]

[0073] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A trapezoidal cross-section spiral tooth, comprising: The moving vortex tooth (1) and the stationary vortex tooth (2) are characterized by: The tooth thickness of the moving vortex tooth (1) decreases linearly from the tooth root to the tooth tip along the axial direction, forming a continuous trapezoidal cross section in the section parallel to the axial direction. The angle formed between the inner wall of the moving vortex tooth (1) and the axial direction is the inner wall draft angle β1, and its expression is: The angle formed between the outer wall of the moving vortex tooth (1) and the axial direction is the outer wall draft angle β2, and its expression is: Where γ is the draft adjustment factor, γ∈[-1,1]; T1 is the wall thickness at the tip of the moving scroll tooth, T2 is the wall thickness at the root of the moving scroll tooth, and H is the height of the moving scroll tooth. The variation law of tooth thickness T along the axial height z of the moving vortex tooth (1) is as follows: in, Let be the involute development angle, z be the axial height, and z∈[0,H]; The moving vortex tooth (1) and the stationary vortex tooth (2) are completely identical. The moving vortex tooth (1) rotates 180° relative to the center point O and then completely overlaps with the stationary vortex tooth (2). During the working process of revolution and translation, the moving vortex tooth (1) can achieve correct meshing with the stationary vortex tooth (2).

2. The design method of a trapezoidal cross-section vortex tooth as described in claim 1, characterized in that: Includes the following steps: 1) Establish a two-dimensional coordinate system with the center point O of the vortex tooth as the origin, and give the following constants: base circle radius R b Initial phase angle α, tooth height H of moving vortex tooth (1), tooth tip wall thickness T1 of moving vortex tooth (1), tooth root wall thickness T2 of moving vortex tooth (1), draft adjustment factor γ; 2) Generate the basic profile at the root of the moving spiral tooth (1) (z=0), that is, the profiles of the inner and outer walls at the root of the moving spiral tooth (1): The equation for the inner wall profile of the moving vortex tooth (1) is: The equation of the outer wall profile of the moving vortex tooth (1) is: Among them, R b The radius of the base circle; α is the involute development angle; α is the initial phase angle. 3) Calculate the draft parameters: Based on the root end wall thickness T2, the tip wall thickness T1, the height H, and the draft adjustment factor γ of the moving scroll tooth (1), calculate the draft angles of the inner and outer walls of the moving scroll tooth (1): The expression for the inner wall draft angle β1 of the moving vortex tooth (1) is: The draft angle β2 of the outer wall of the moving vortex tooth (1) is expressed as follows: Where γ is the draft adjustment factor, γ∈[-1,1]; T1 is the wall thickness at the tip of the moving volute tooth (1), T2 is the wall thickness at the root of the moving volute tooth (1), and H is the tooth height of the moving volute tooth (1). 4) Perform draft treatment on the basic profile at the root of the moving volute tooth (1) to generate a trapezoidal cross-section volute tooth: Combined with the draft angle parameters, the basic profile at the tooth root is drafted along the axial direction to generate the inner and outer profiles of the moving vortex tooth (1) at any axial height z. The equation of the inner wall profile of the moving vortex tooth (1) at any axial height z is: The equation of the outer wall profile of the moving vortex tooth (1) at any axial height z is: Among them, R b The radius of the base circle; α is the involute development angle; z is the initial phase angle; β is the axial height, z∈[0,H]; γ is the draft angle; γ is the draft adjustment factor, γ∈[-1,1]; 5) Generate the profile of the stationary vortex tooth (2): Rotate the profile of the moving vortex tooth (1) 180° relative to the center point O to obtain the inner and outer profiles of the stationary vortex tooth (2): The equation for the inner wall profile of the static vortex tooth (2) is: The equation for the outer wall profile of the stationary vortex gear (2) is:

3. A scroll compressor, characterized in that: Using a trapezoidal cross-section vortex tooth as described in claim 1.

4. A vortex expander, characterized in that: Using a trapezoidal cross-section vortex tooth as described in claim 1.

5. A vortex vacuum pump, characterized in that: Using a trapezoidal cross-section vortex tooth as described in claim 1.

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