A volute mounting assembly and a design method of a volute mounting assembly

Abstract

The present application relates to a kind of volute mounting assembly and the design method of volute mounting assembly, the volute includes front cover, back cover and the ring wall of connecting two, it is characterized in that the volute mounting assembly includes: at least two mounting brackets, each mounting bracket includes at least three legs, the first end of each leg is connected with the outer wall of corresponding ring wall, the second end of each leg extends towards the direction away from ring wall and is connected with external installation base.The advantage is that: by moving the mounting piece in the thickness direction of volute to the outer wall of ring wall of volute, so as to avoid the interference of fastener and volute, so that the height of volute mounting assembly is no longer limited by the length of fastener, and thinner volute mounting assembly can be designed;And using the fixing mode of at least three legs, the installation stability of the mounting bracket can be guaranteed;In addition, based on the stress condition of the volute under the falling impact condition of range hood, the mounting bracket is designed to cope with the impact load of volute.

Description

Technical Field

[0001] This invention relates to the field of kitchen equipment technology, and in particular to a volute mounting assembly and a design method for the volute mounting assembly. Background Technology

[0002] Range hoods have become an indispensable kitchen appliance in modern homes. They operate on the principles of fluid dynamics, using a fan system installed inside to draw in cooking fumes and filtering out some grease particles with a filter. The fan system includes a volute, an impeller housed within the volute, and a motor that drives the impeller. When the impeller rotates, a negative pressure suction is generated at the center of the fan, drawing the cooking fumes from below into the system. After being accelerated by the fan, the volute collects the fumes and guides them outdoors.

[0003] In existing technologies, fan systems are typically installed inside range hoods via a volute mounting bracket. For example, Chinese utility model patent ZL201820770468.2 (authorization announcement number CN 208418862U) discloses a volute assembly for a range hood. This volute has a bracket for mounting, which protrudes away from the volute. However, this volute assembly has the following limitations: due to the relatively large mass of the volute assembly, and considering the risk of drops during transportation, the fasteners are usually quite thick and long to ensure the reliability of the range hood. Therefore, it is necessary to increase the distance between the mounting holes on the protrusion and the back plate of the volute to accommodate the fasteners. However, if the distance between the protrusion and the back plate is too large, the overall volume of the volute increases, making it unsuitable for ultra-thin range hoods. Therefore, further improvements to the existing technology are needed. Summary of the Invention

[0004] The first technical problem to be solved by the present invention is to provide a volute mounting assembly that can reduce the size in the thickness direction of the volute to adapt to ultra-thin range hoods, in contrast to the above-mentioned prior art.

[0005] The second technical problem to be solved by the present invention is to provide a design method for the above-mentioned volute mounting assembly.

[0006] The technical solution adopted by the present invention to solve the first technical problem mentioned above is: a volute mounting assembly, wherein the volute includes a front cover plate, a rear cover plate, and an annular wall connecting the two, characterized in that the volute mounting assembly includes:

[0007] At least two mounting brackets, each mounting bracket including at least three legs, the first end of each leg being connected to the outer wall of the corresponding ring wall, and the second end of each leg extending away from the ring wall and connected to the external mounting base.

[0008] To improve the stability and ease of assembly of the mounting brackets, each mounting bracket also includes a first mounting base and a second mounting base. The first end of each leg is circumferentially constrained to the first mounting base, and the second end of each leg is circumferentially constrained to the second mounting base. The second end of each leg is connected to the external mounting base through the second mounting base. The first and second mounting bases can be connected using structures such as rings or triangles.

[0009] Preferably, the volute mounting assembly further includes a mounting member corresponding to each mounting bracket, the first mounting seat being constrained on the mounting member, and the mounting member being mounted on the volute.

[0010] Since the ring wall of the volute is curved, it is inconvenient to fix. Preferably, the mounting component is a U-shaped structure with the opening of the U-shaped structure facing the ring wall, and the two opposite walls of the U-shaped structure are respectively connected to the outer wall of the front cover plate and the outer wall of the rear cover plate.

[0011] The technical solution adopted by the present invention to solve the second technical problem mentioned above is: a design method for a volute mounting assembly as described above, characterized in that it includes: performing a stress analysis on the volute mounting assembly to obtain the stress magnitude of each mounting bracket, and designing the mounting bracket according to the stress magnitude of each mounting bracket to obtain the designed mounting bracket.

[0012] Preferably, there are two mounting brackets, which are disposed substantially opposite to each other on the side wall of the annular wall.

[0013] Preferably, the force magnitude of each mounting bracket is obtained as follows:

[0014] The two mounting brackets are denoted as the first mounting bracket and the second mounting bracket, respectively. The direction perpendicular to the front cover plate is the X-axis direction, and the direction parallel to the front cover plate is the Y-axis direction. The magnitudes of the forces F1 and F2 of the first mounting bracket and the second mounting bracket are obtained according to the following two formulas.

[0015] F1 + F2 = F

[0016] F1*L1=F2*L2

[0017] Where F is the impact load on the volute, the direction of F is along the X-axis and acts on the centerline of the volute, L1 is the distance between the centerline of the volute and the first mounting bracket, L2 is the distance between the centerline of the volute and the first end of all the legs of the first mounting bracket, and L3 is the distance between the centerline of the volute and the first end of all the legs of the second mounting bracket.

[0018] To simplify the calculation, the formula for F is as follows:

[0019]

[0020] Where K1 is the first empirical safety factor, E is the elastic modulus of the package, the package is used to package a range hood with a built-in volute, M is the mass of the volute, m is the mass of the range hood with the built-in volute, ▽d is the maximum distance the package is compressed during the impact, and d is the initial thickness of the package.

[0021] To simplify the stress model, all mounting brackets have the same structure and are configured such that: the first mounting base and the second mounting base are both annular, the diameter D1 of the first mounting base is smaller than the diameter D2 of the second mounting base, the distance between the first mounting base and the second mounting base is L, and each mounting bracket includes three legs, with the first end and the second end of each leg evenly distributed along the first mounting base and the second mounting base, respectively.

[0022] To cope with the stress on the volute casing under the impact of a fall from the range hood, the design method of the first mounting bracket is the same as that of the second mounting bracket. The specific process of designing the first mounting bracket according to the magnitude of the stress on it is as follows:

[0023] The bending deformation ε of each leg in the first mounting bracket is calculated according to the following formula;

[0024]

[0025] Where E is the elastic modulus of the support leg, and d is the diameter of each support leg;

[0026] Substituting the above formula for calculating ε into... In the middle, L g The length of the support leg, That is, we get:

[0027] And according to ε0 is the preset bending deformation amount, which yields...

[0028] The final design of each leg in the first mounting bracket must meet the following conditions:

[0029]

[0030] K2 is the second empirical safety factor.

[0031] Compared with the prior art, the advantages of the present invention are as follows: by moving the mounting component in the thickness direction of the volute to the outside of the volute's annular wall, a larger installation space is provided between the volute mounting assembly and the external mounting base, avoiding interference between the fasteners and the volute, and the height of the volute mounting assembly is no longer limited by the length of the fasteners, allowing for the design of a thinner volute mounting assembly; and the use of at least three support legs ensures the installation stability of the mounting bracket; furthermore, the mounting bracket is designed based on the stress conditions of the volute under the impact of a range hood falling, in order to cope with the impact load on the volute. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the volute mounting structure in an embodiment of the present invention;

[0033] Figure 2 for Figure 1 Partial structural diagram (external installation foundation omitted);

[0034] Figure 3 for Figure 2 Another perspective structural diagram;

[0035] Figure 4 This is a schematic diagram of the mounting bracket in an embodiment of the present invention. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0037] In this embodiment, the volute 1 includes a front cover plate 11, a rear cover plate 12, and an annular wall 13 connecting the two. To achieve the installation of the volute, the volute mounting assembly includes at least two mounting brackets, each mounting bracket including at least three legs 20. The first end of each leg 20 is connected to the outer wall of the corresponding annular wall 13, and the second end of each leg 20 extends away from the annular wall 13 and is connected to the external mounting base 3. In this embodiment, the external mounting base 3 is the inner cavity of the range hood, thus allowing the volute 1 to be installed inside the range hood. Figures 1-4 As shown, there are two mounting brackets in this embodiment, which are basically opposite to each other on the side wall of the annular wall 13.

[0038] To install all the legs 20, each mounting bracket also includes a first mounting base 2a, a second mounting base 2b, and a mounting member 2c. The first end of each leg 20 is circumferentially constrained to the first mounting base 2a, and the second end of each leg 20 is circumferentially constrained to the second mounting base 2b. The second end of each leg 20 is connected to the external mounting base 3 through the second mounting base 2b. The first mounting base 2a is constrained to the mounting member 2c, and the mounting member 2c is mounted on the volute 1.

[0039] In this embodiment, all mounting brackets have the same structure and are configured such that: the first mounting base 2a and the second mounting base 2b are both annular, the diameter D1 of the first mounting base 2a is smaller than the diameter D2 of the second mounting base 2b, the distance between the first mounting base 2a and the second mounting base 2b is L, and each mounting bracket includes three legs 20, the first end and the second end of each leg 20 being evenly distributed along the first mounting base 2a and the second mounting base 2b, respectively.

[0040] like Figure 4 As shown, the mounting component 2c in this embodiment is a U-shaped structure. The opening of the U-shaped structure faces the annular wall 13, and the two opposite walls of the U-shaped structure are connected to the outer walls of the front cover plate 11 and the rear cover plate 12, respectively. Since the annular wall 13 of the volute is curved, fixing it is inconvenient. Therefore, the function of this U-shaped structure is to facilitate the mounting bracket to be installed on one side of the annular wall 13 of the volute. The mounting component 2c is fixed to the outer walls of the front cover plate 11 and the rear cover plate 12 by riveting or welding, respectively. In addition, the corners of the mounting component 2c are provided with a pressing to improve its rigidity. Each support leg 20 is also usually fixed to the mounting component 2c by screw connection or welding, and is fixed to the external mounting base 3 by screws.

[0041] Since the volute mounting assembly is the load-bearing structure that fixes the entire volute to the external mounting base 3 (the inner cavity of the range hood), the rigidity and strength of the volute mounting assembly must be considered in its design, taking into account factors such as the impact of the range hood falling, the dynamic imbalance of the motor, and the weight of the volute itself.

[0042] The design method of the volute mounting assembly in this embodiment includes: performing a stress analysis on the volute mounting assembly to obtain the stress magnitude of each mounting bracket, and designing the mounting bracket according to the stress magnitude of each mounting bracket to obtain the designed mounting bracket.

[0043] The method for obtaining the force magnitude of each mounting bracket is as follows:

[0044] like Figure 3 As shown, the two mounting brackets are respectively referred to as the first mounting bracket 21 and the second mounting bracket 22. The direction perpendicular to the front cover plate 11 is the X-axis direction, and the direction parallel to the front cover plate 11 is the Y-axis direction. The magnitudes of the forces F1 on the first mounting bracket 21 and F2 on the second mounting bracket 22 are obtained according to the following two formulas.

[0045] F1 + F2 = F

[0046] F1*L1=F2*L2

[0047] Where F is the impact load on the volute, the direction of F is along the X-axis and acts on the center line of the volute, L1 is the distance between the center line of the volute and the first mounting bracket 21, L2 is the distance between the center line of the volute and the first end of all the legs of the first mounting bracket 21, and L2 is the distance between the center line of the volute and the first end of all the legs of the second mounting bracket.

[0048] The formula for calculating F above is:

[0049]

[0050] Where K1 is the first empirical safety factor, E is the elastic modulus of the packaging, the packaging is used to package a range hood with a built-in volute, M is the mass of the volute, m is the mass of the range hood with the built-in volute, ▽d is the maximum distance the packaging is compressed during the impact, and d is the initial thickness of the packaging. In this embodiment, the packaging is foam.

[0051] The method for obtaining F above is as follows:

[0052] Among the various loads on the volute, the instantaneous load caused by the impact of the range hood falling during transportation and handling is the largest.

[0053] Specifically, the magnitude of the load generated by a range hood falling can be calculated as follows:

[0054] The impact load can be estimated by considering the kinetic energy of the volute during free fall and the momentum change during the impact. First, the maximum velocity v of the volute before falling needs to be calculated, which can be obtained by considering its kinetic energy during free fall:

[0055]

[0056] Where g is the acceleration due to gravity, and h is the maximum acceptable drop height of the range hood during the design process, which depends on the testing and evaluation methods of the transport packaging by the designers. The product drop height requirement is usually related to the product quality. The greater the quality, the lower the design drop height, which is usually between 150mm and 600mm.

[0057] The impact load F can be further estimated by considering the momentum change during the impact process. The impact load F can be calculated using the following formula:

[0058] F=▽p / ▽t

[0059] Where ▽p is the change in momentum and ▽t is the impact time;

[0060] Since momentum p equals mass M multiplied by velocity v, the change in momentum ▽p can be expressed as:

[0061] ▽p=Mv-Mv0

[0062] Where v0 is the initial velocity (which is 0 in this case because the range hood starts falling from rest); therefore, it is easy to obtain:

[0063]

[0064] Finally, substituting these values ​​into the formula for the impact load F, we obtain...

[0065]

[0066] Since the volute is under load during the calculation, M is the mass of the volute, which is considered known in this embodiment;

[0067] Calculating the impact time Δt of a heavy object dropped from height h onto a hard, flat surface requires considering several factors: the mass of the object, the drop height h, the physical properties of the packaging foam (such as thickness and cushioning capacity), and the hardness of the ground. Due to the complexity of these factors, accurate calculation of the impact time usually requires detailed physical models and experimental data. However, a simplified estimation method can be used in the early stages of design.

[0068] The impact time Δt primarily depends on the compressibility and thickness of the foam. When a heavy object impacts the ground, the foam compresses and absorbs energy, thus prolonging the impact time and reducing the impact force. A simplified model can be considered as follows: assuming the foam provides a nearly constant deceleration 'a', then the impact time T can be estimated using the following formula:

[0069]

[0070] Where v is the velocity of the object when it hits the ground, and a is the deceleration.

[0071] To estimate the aforementioned deceleration 'a', we assume that the foam exhibits linear elasticity when compressed, meaning that the stress (force / area) of the foam is proportional to the strain (relative deformation), and that the foam provides an approximately constant deceleration throughout the compression process.

[0072] Use Hooke's Law to estimate the maximum compressive force Fy on the foam:

[0073] Fy=K1*E*▽d / d

[0074] K1 is the first empirical safety factor used to compensate for errors caused by the estimation method. K1 is usually taken as 2-3. The elastic modulus E of the foam is a physical quantity that measures the stiffness of the material, which depends on the type of material and is considered known in this embodiment. The ratio of maximum compression to initial thickness (▽d / d): the ratio of the maximum distance the foam is compressed during impact to the initial thickness of the foam. To avoid the foam from being destroyed, this ratio is usually not more than 10%. The specific setting value is based on experience and is considered known in this embodiment.

[0075] Calculate the deceleration a according to Newton's second law:

[0076] a=Fy / m

[0077] Where m is the mass of the range hood, which is considered known in this embodiment.

[0078] Combining the above formulas, the impact load F on the volute can be expressed as:

[0079]

[0080] like Figure 1 As shown, the volute mounting assembly fixes the volute along the Y-axis, and the volute's air outlet is fixed to the top of the range hood's inner cavity with screws. Therefore, when the volute is subjected to impact loads along the Y and Z axes, the compressive and tensile strengths of the volute mounting assembly and the top plate screws are primarily tested. Impact loads along the X-axis, however, test the bending strength of the volute mounting assembly. Based on the mechanical properties of metallic materials, it is easy to conclude that the volute mounting assembly is most prone to deformation and failure when subjected to impact loads along the X-axis. To simplify the calculation, it is assumed that the impact load on the volute in this embodiment is along the positive X-axis, with its point of application at the center of the volute.

[0081] Furthermore, the design method of the first mounting bracket 21 in this embodiment is the same as the design method of the second mounting bracket 22. The specific process of designing the first mounting bracket 21 according to the magnitude of the force it is subjected to is as follows:

[0082] The bending deformation ε of each leg 20 in the first mounting bracket 21 is calculated according to the following formula;

[0083]

[0084] Where E is the elastic modulus of the support 20, and d is the diameter of each support 20;

[0085] Substituting the above formula for calculating ε into... In the middle, L g The length of the support leg is 20. That is, we get:

[0086] And according to ε0 is the preset bending deformation amount, which yields...

[0087] The final design of each leg 20 in the first mounting bracket 21 must meet the following conditions:

[0088]

[0089] K2 is the second empirical safety factor.

[0090] In this embodiment, each support leg 20 adopts a cylindrical structure with the same diameter.

[0091] The calculation basis for the bending deformation ε of each leg 20 in the first mounting bracket 21 mentioned above is as follows:

[0092] Determine the force distribution: The force borne by each leg is (F1 / 3), because F1 is evenly distributed among the three legs;

[0093] Applying the bending formula: The amount of bending deformation can be calculated using the bending formula, which is usually expressed as:

[0094]

[0095] Where M is the bending moment; bending stiffness EI (where E is the elastic modulus and I is the moment of inertia), L g The length of the support leg is 20.

[0096] The bending moment M can be calculated based on the force borne by the support and the lever arm. In this case, the lever arm is approximately equal to the distance L between the first mounting base 2a and the second mounting base 2b. Therefore,

[0097]

[0098] The moment of inertia I depends on the cross-sectional properties of the support leg. For a cylindrical support leg with diameter d, its moment of inertia is...

[0099]

[0100] Combining the above formulas

[0101]

[0102] It is generally considered that the ratio of the bending deformation of the volute mounting assembly to that of the support leg is less than ε0 (ε0 = 5% in this embodiment), indicating that it operates within its elastic limit, i.e., ε / L. g A value ≤0.05 is considered acceptable for the strength of the volute mounting assembly; L, D1, and D2 mentioned above are all known values; and to compensate for errors caused by the estimation method, then... K2 is usually taken as 1.5 to 2.

[0103] The specification and claims of this invention use terms indicating direction, such as "front," "rear," "upper," "lower," "left," "right," "side," "top," and "bottom," to describe various exemplary structural parts and elements of the invention. However, these terms are used herein merely for ease of explanation and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in this invention can be arranged in different orientations, these terms indicating direction are for illustrative purposes only and should not be considered as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

Claims

1. A design method for a volute mounting assembly, wherein the volute (1) includes a front cover plate (11), a rear cover plate (12), and an annular wall (13) connecting the two, characterized in that... The volute mounting assembly includes: Two mounting brackets are specified as a first mounting bracket (21) and a second mounting bracket (22). Each mounting bracket also includes a first mounting base (2a) and a second mounting base (2b). All mounting brackets have the same structure and are configured such that the first mounting base (2a) and the second mounting base (2b) are both annular, and the diameter of the first mounting base (2a) is... Smaller than the diameter of the second mounting base (2b) The distance between the first mounting base (2a) and the second mounting base (2b) is Each mounting bracket includes three legs (20), the first end and the second end of each leg (20) are evenly distributed along the first mounting seat (2a) and the second mounting seat (2b) respectively; the first end of each leg (20) is circumferentially constrained on the first mounting seat (2a), the second end of each leg (20) is circumferentially constrained on the second mounting seat (2b), the first end of each leg (20) is connected to the outer wall of the corresponding ring wall (13), and the second end of each leg (20) extends in a direction away from the ring wall (13) and is connected to the external mounting base (3) through the second mounting seat (2b); the design method of the volute mounting assembly includes: performing a stress analysis on the volute mounting assembly to obtain the stress magnitude of each mounting bracket, and designing the mounting bracket according to the stress magnitude of each mounting bracket to obtain the designed mounting bracket; The design method of the first mounting bracket (21) is the same as that of the second mounting bracket (22), wherein the design method is based on the force of the first mounting bracket (21). The specific process of designing the size of the first mounting bracket (21) is as follows: The bending deformation of each leg (20) in the first mounting bracket (21) is calculated according to the following formula. ; = in, The elastic modulus of the support (20) is given by... The diameter of each leg (20); The above Substituting the calculation formula into middle, The length of the support leg (20) That is, we get: ; And according to , The preset bending deformation amount is obtained. ≥ ; The final design of each leg (20) in the first mounting bracket (21) must meet the following conditions: ≥K2* K2 is the second empirical safety factor.

2. The design method according to claim 1, characterized in that: The volute mounting assembly further includes a mounting element (2c) corresponding to each mounting bracket, the first mounting seat (2a) being constrained on the mounting element (2c), and the mounting element (2c) being mounted on the volute.

3. The design method according to claim 2, characterized in that: The mounting component (2c) is a U-shaped structure with the opening of the U-shaped structure facing the annular wall (13). The two opposite walls of the U-shaped structure are respectively connected to the outer wall of the front cover plate (11) and the outer wall of the rear cover plate (12).

4. The design method according to claim 1, characterized in that: The first mounting bracket (21) and the second mounting bracket (22) are disposed opposite to each other on the side wall of the annular wall (13).

5. The design method according to claim 4, characterized in that: The method for obtaining the force magnitude of the first mounting bracket (21) and the second mounting bracket (22) is as follows: Taking the direction perpendicular to the front cover plate (11) as the X-axis direction and the direction parallel to the front cover plate (11) as the Y-axis direction, the force on the first mounting bracket (21) is obtained according to the following two formulas. Force on the second mounting bracket (22) Size; in, Let F be the impact load on the volute, with its direction along the X-axis and acting on the centerline of the volute. The distance between the center line of the volute and the first mounting bracket (21) is... The distance between the centerline of the volute and the first end of all the legs of the first mounting bracket (21) is [distance]. The distance between the center line of the volute and the first end of all the legs of the second mounting bracket (22).

6. The design method according to claim 5, characterized in that: The formula for calculating F is: in, As the first empirical safety factor, The elastic modulus of the package is used to package a range hood with a built-in volute. For the mass of the volute, For the quality of range hoods with built-in volutes, This represents the maximum distance the package is compressed during the impact. This represents the initial thickness of the packaging.

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