Fan guard design method

Abstract

The application discloses a fan protective cover design method in the technical field of fan device manufacturing, and comprises the following steps: 1, obtaining the size of the fan protective cover outer frame and presetting the size of the center disc; 2, arranging the base rib between the center disc and the fan protective cover outer frame, and forming the concentric ring area among the center disc, the base rib and the fan protective cover outer frame; 3, arranging the radial rib in the ring area to be arranged, and arranging the first type of radial rib in the ring area close to the protective cover outer frame; the first type of radial rib satisfies that the shortest distance between any optional point on the radial rib and the adjacent radial rib in the same ring area changes by not more than 5%. The shortest distance between the radial ribs of the product manufactured according to the method changes little, the arrangement number and density of the radial rib can be reduced, and the ventilation area under the same condition can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ventilation device manufacturing, in particular to a fan protective cover design method. BACKGROUND

[0002] In the current protective cover design, the center of the protective cover is usually set at the motor shaft area of the fan system, and the edge of the protective cover is away from the motor shaft area of the fan system. According to the safety technology requirements of the protective cover, in order to prevent fingers or other objects from entering the inside of the machine through the protective cover, the following requirements are made on the protective cover grid size: the grid formed by the staggered ribs of the protective cover does not allow a cylinder with a diameter of 12.5mm to pass directly through the grid gap.

[0003] Based on the above requirements and considering the strength requirements of the protective cover, there are currently two design methods. The first method is to design a dense concentric circle rib structure with the center of the protective cover as the center, and then use the sparse ribs radiating from the center to the edge to connect and fix the dense concentric circle ribs, forming an interlaced grid pattern. The second method is to design a dense emission rib pattern with the center of the protective cover as the center, extending from the center to the edge, and then interlacing the sparse concentric circle ribs or sparse radial ribs with the dense emission ribs to form a grid pattern. In the above two design methods, there is a transition process of the protective cover grid size from the center to the edge, and the shortest distance between adjacent radial ribs changes constantly. Specifically, as the adjacent ribs radiate outward from the center, the shortest distance between them gradually increases. Therefore, the effective ventilation area of the protective cover near the center will decrease.

[0004] The Chinese invention patent with the publication number CN103900167B and the name "fan air outlet protective cover, fan and air conditioner outdoor unit" discloses an air outlet protective cover. In this application, although different warp piece groups are arranged in different weft circle groups, the shortest distance between adjacent warp pieces still changes linearly during the spreading process from the center to the outside. Therefore, the problem of the effective ventilation area of the protective cover near the center decreasing still exists, as the shortest distance between adjacent ribs gradually increases as they radiate outward from the center. SUMMARY

[0005] To overcome the problem of the effective ventilation area of the protective cover near the center decreasing in the current protective cover grid design, the present application provides a fan protective cover design method.

[0006] The technical solution adopted by the present application to solve its technical problems is:

[0007] A fan protective cover design method, comprising the following steps:

[0008] Step 1, obtaining the size of the fan protective cover outer frame, and presetting the size of the center disc;

[0009] Step 2, arranging a base rib between the center disc and the fan protective cover outer frame, and forming a plurality of concentric annular regions among the center disc, the base rib and the fan protective cover outer frame;

[0010] Step 3, arranging a radial rib in the annular region to be arranged, and arranging a first type of radial rib in a plurality of annular regions close to the protective cover outer frame, the first type of radial rib satisfying that the shortest distance between any optional point on the radial rib and the adjacent radial rib in the same annular region changes by no more than 5%.

[0011] In the method, the radial rib arranged in the outer layer, i.e. in a plurality of annular regions close to the protective cover outer frame, is a first type of radial rib, and the shortest distance between any optional point on the first type of radial rib and the adjacent radial rib in the same annular region changes by no more than 5%. Unlike the prior art, the shortest distance between the adjacent radial ribs gradually increases outward from the center disc. According to the method, the shortest distance between the radial ribs changes little, which can reduce the number and density of the arranged radial ribs, and further improve the ventilation area under the same conditions. Since the region close to the center disc is a non-main air outlet region, the plurality of annular regions close to the protective cover outer frame are preferentially implemented as described above. The non-main air outlet region close to the center disc can be implemented as described above, or can be implemented according to the prior art, such as the background art or the center disc emitting rays outward, which is not limited here.

[0012] Here, the change amplitude of the shortest distance refers to the ratio of the difference between the maximum value and the minimum value to the minimum value.

[0013] Further, the specific steps of arranging the first type of radial rib in step 3 are as follows:

[0014] Step 31, assuming that the inner circle of any annular region to be arranged with the first type of radial rib is C1, the outer circle is C2, the inner diameter is R1, the outer diameter is R2, the center is O, m radial ribs need to be arranged, and the preset shortest distance between any optional point on the radial rib and the adjacent radial rib in the same annular region is D;

[0015] Step 32, uniformly setting s first auxiliary ribs with the center O in the annular region, which are respectively I1, I2, … IS, s is a positive integer greater than or equal to 3, and s+1 auxiliary annular regions are divided, and a ray is drawn from the center O, and the center O intersects the inner circle, the first auxiliary rib and the outer circle at points A, I1… IS and B respectively;

[0016] Step 33, calculating the chord length L corresponding to the central angle of 360° / m of the circles C1, I1, I2, … IS and C2 respectively A , LI1 , L I2 , … LIS, LB;

[0017] Set angle ∠A = acos(D / L A ), ∠I1 = acos(D / L I1 ), ∠I2 = acos(D / L I2 ), … ∠IS = acos(D / L IS ), ∠B = acos(D / L B );

[0018] Step 34, from point A, draw a ray in the direction away from the center O, which forms an angle of ∠A with OB, from point I1, draw a ray in the direction away from the center O, which forms an angle of ∠I1 with OB, from point I2, draw a ray in the direction away from the center O, which forms an angle of ∠I2 with OB, … from point IS, draw a ray in the direction away from the center O, which forms an angle of ∠IS with OB, from point B, draw a ray in the direction away from the center O, which forms an angle of ∠B with OB, and all the above rays are on the same side of OB.

[0019] Step 35, in each auxiliary circular ring area, set a second auxiliary muscle with the center O, the second auxiliary muscle is located in the middle position of the auxiliary circular ring area, and each ray with the starting point on the outer circle of the auxiliary circular ring area is reversely extended to intersect with the second auxiliary muscle in the auxiliary circular ring area, and the reversely extended ray is rotated around the center O, so that the two rays with the starting point in the same auxiliary circular ring area all intersect with the second auxiliary muscle in the auxiliary circular ring area.

[0020] Step 36, connect points A, the intersection points on the second auxiliary muscle and point B in sequence with a smooth curve to form a radial muscle AB, and take the center O as the circle point, and arrange m radial muscles AB in the circular ring area.

[0021] In the method, the preset minimum distance D is slightly lower than the design standard. For example, when 12.5 mm in the safety design requirement of the protective cover is selected, the preset minimum distance D can be set to 11.9 mm, and at this time, there is a 5% floating amount relative to 12.5 mm, which avoids the influence of errors in design and manufacturing on the quality of subsequent products. The number of radial muscles in the circular ring area can be roughly calculated according to the preset minimum distance D and the inner diameter of the circular ring area. For example, m radial muscles divide the inner diameter into m circular arc segments, and the chord length corresponding to each circular arc segment is greater than or equal to D, so as to obtain the number range of radial muscles. After completing the radial muscle layout in the circular ring area, the number of radial muscles can be adjusted according to the actual demand. After completing the overall layout of the radial muscles in the fan protective cover, the number of radial muscles or the selection can be adjusted according to the overall strength of the fan protective cover.

[0022] Further, step 36 specifically includes the following steps:

[0023] Step 361, connecting point A, the intersection on the second auxiliary rib and point B in sequence with a smooth curve, and presetting the curve length L range;

[0024] Step 362, judging the relationship between the actual curve AB length and the preset curve length L, if the curve AB length falls within the preset curve length L range, executing step 363, if the curve AB length does not fall within the preset curve length L range, adjusting the position of the basic rib so that the curve AB length falls within the preset curve length range, and then executing step 363;

[0025] Step 343, taking the center O as the circle point, and arranging m radial ribs AB in the circular ring region.

[0026] In the method, the preset curve length L range is generated by the above method, and the radial rib curve length in different circular ring regions can be controlled to be basically the same by adjusting the position of the basic rib. In combination with steps 31-35, the shortest distance between the radial ribs is basically equal, at this time, the gap and the curve length between the multiple grids formed by the radial ribs and the basic rib are uniform, and the overall strength distribution is uniform. On the premise of meeting the strength requirement, the strength of the partial region of the protective cover is avoided, the weight of the protective cover can be reduced, and the cost is reduced.

[0027] Further, in step 34, at least one group of two adjacent circular ring regions is located on different sides of the ray OB in step 34.

[0028] In the method, when the radial ribs are arranged in the adjacent two circular ring regions respectively, the corresponding rays are located on different sides of OB in step 34. Corresponding to the fan protective cover, the radial ribs in the adjacent circular ring regions have different rotation directions, the radial ribs in the adjacent two regions have opposite rotation directions, and the reverse wind is formed in the actual work. The reverse wind is mixed with each other, and the noise in the operation of the fan is reduced.

[0029] Further, step 36 specifically includes the following steps:

[0030] Step 36a, connecting point A, the intersection on the second auxiliary rib and point B in sequence with a smooth curve, and presetting the angle range between the straight line AB and the straight line OA;

[0031] Step 36b, judging the relationship between the actual angle between the straight line AB and the straight line OA and the preset angle range, if the angle between the straight line AB and the straight line OA falls within the preset angle range, executing step 36c, if the angle between the straight line AB and the straight line OA does not fall within the preset angle range, adjusting the number m of radial ribs and returning to step 31 until the angle between the straight line AB and the straight line OA is consistent with the preset range, and then executing step 36c;

[0032] Step 36c, taking the center O as the circle point, and arranging m radial ribs AB in the circular ring region.

[0033] In the method, the line connecting the starting point and the ending point of the radial rib is AB, and the line connecting the center and the starting point of the radial rib is OA. The number of the radial ribs in the annular region can be adjusted, and then the included angle of the straight line AB and the straight line OA can be adjusted. In the implementation, according to different fan characteristics or the preset included angle range of the actual demand of the air outlet angle, after the layout of the radial ribs in a single annular region is completed, the included angle can be adjusted by changing the number of the radial ribs.

[0034] Further, the annular region to be arranged with the radial rib in step 3 satisfies that the ratio of the outer diameter to the inner diameter is less than 2.

[0035] In the method, preferably, each annular region arranged with the radial rib satisfies that the ratio of the outer diameter to the inner diameter is less than 2. This is mainly to balance the subsequent strength test and the aforementioned angle requirement. In the specific implementation, it is reflected in the requirement for the arrangement position of the base rib in step 2.

[0036] Further, the base rib is arranged from the outer frame of the fan protective cover to the inside in step 2.

[0037] In the method, preferably, the base rib is arranged from the outer frame of the fan protective cover to the inside. The size of the protective cover frame is determined according to the fan specification, and the size of the center disc can be adjusted. In this way, there is a design margin in the innermost layer, which can simplify the design process. Specifically, if the protective cover increases the distance between the base ribs, such as the case where the length of the limit curve is consistent, the position of the base rib needs to be adjusted to meet the length requirement of the curve in the design. In the method of designing from the inside to the outside, if the outermost layer cannot meet the length requirement of the curve, since the size of the outer frame is fixed, the base rib and the radial rib that have been arranged need to be adjusted, and the aforementioned design process needs to be iterated. Therefore, it is preferred that the base rib is arranged from the outer frame of the fan protective cover to the inside.

[0038] The beneficial effects of the present application are:

[0039] 1. When the method is applied to the design of the fan protective cover, the layout mode of the protective cover rib can be optimized, and specifically, the radial rib curve is optimized, so that the shortest distance between the radial ribs in the same annular region changes little, the number and density of the radial ribs are reduced as much as possible under the premise of meeting the safety distance between the ribs, and then the maximum air outlet area in the annular region is achieved, and the overall ventilation efficiency of the protective cover is improved.

[0040] 2. In the method, on the basis that the shortest distance between the radial ribs changes little, the length of the radial rib curve is limited to be consistent, and at this time, the size of the region surrounded by the radial rib and the base rib is basically stable. Under the premise of meeting the strength requirement of the protective cover, the weight of the protective cover can be maximally reduced, and the cost can be reduced.

[0041] 3、 In the method, the angle and direction of the radial ribs can be adjusted according to the requirements in implementation, so that the balance adjustment of the high air outlet efficiency and the air outlet direction is achieved, and the adjustment flexibility is large, so as to adapt to different application occasions. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Figure a is a sub-step schematic diagram of step 3 of the fan protective cover design method of the application;

[0043] Figure 2 Figure b is a sub-step schematic diagram of step 3 of the fan protective cover design method of the application;

[0044] Figure 3 Figure c is a sub-step schematic diagram of step 3 of the fan protective cover design method of the application;

[0045] Figure 4 Figure d is a sub-step schematic diagram of step 3 of the fan protective cover design method of the application;

[0046] Figure 5 Figure a is an embodiment effect schematic diagram of the fan protective cover design method of the application;

[0047] Figure 6 Figure b is an embodiment effect schematic diagram of the fan protective cover design method of the application;

[0048] Figure 7 Figure c is an embodiment effect schematic diagram of the fan protective cover design method of the application.

[0049] In the figure, 5 is a first auxiliary rib, 6 is a second auxiliary rib, 10 is a first radial rib, 11 is a base rib, 12 is a center disc, and 13 is a protective cover outer frame. DETAILED DESCRIPTION

[0050] The application will be further described below in combination with the drawings.

[0051] In order to make the purpose, technical scheme and advantages of the application more clear and explicit, the application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the application and do not limit the application.

[0052] Step 1, obtain the size of the fan protective cover outer frame 13, and preset the size of the center disc 12.

[0053] In this step, the size of the fan protective cover outer frame 13 is determined according to the fan specifications, and the size of the center disc 12 is preset according to the size of the shaft and the center axis of the fan blade.

[0054] Step 2, arrange the base rib 11 between the center disc 12 and the fan protective cover outer frame 13, and form a plurality of concentric circular ring areas between the center disc 12, the base rib 11 and the fan protective cover outer frame 13.

[0055] In a specific implementation, the base ribs 11 can be arranged from outside to inside, i.e. from the outer frame 13 of the fan guard to the inside, or from inside to outside, i.e. from the center disc 12 to the outside.

[0056] Since the size of the center disc 12 can be adjusted, and the size of the outer frame is often fixed according to the fan specifications. Here, it is preferred to arrange the base ribs 11 from outside to inside, i.e. from the outer frame 13 of the fan guard to the inside. When arranging the last layer of base ribs 11, there is a margin left, which can simplify the design process.

[0057] It is obvious that the base ribs 11 can be arranged at one time or sequentially. When the base ribs 11 are arranged at one time, the subsequent step 3 sequentially arranges the radial ribs in the circular ring area where the radial ribs are to be arranged, until the entire guard design is completed. When the base ribs 11 are arranged sequentially, the radial ribs are arranged accordingly, then additional base ribs 11 are added and the radial ribs are arranged accordingly, and the cycle is repeated until the entire guard design is completed.

[0058] In embodiments where the distance between the base ribs 11 needs to be adjusted in the design, it is preferred that the base ribs 11 be arranged sequentially. This avoids the redundancy of the design process caused by multiple adjustments of the position of the base ribs 11 in the design.

[0059] Step 3: Arrange the radial ribs in any circular ring area where the radial ribs are to be arranged. A type of radial rib 10 is arranged in several circular ring areas close to the outer frame 13 of the guard. The type of radial rib 10 satisfies that at any optional point on the radial rib, the shortest distance between the radial rib and the adjacent radial rib in the same circular ring area varies by no more than 5%.

[0060] Unlike the prior art, the shortest distance between adjacent radial ribs gradually increases outward from the center disc 12. According to the method, the shortest distance between the radial ribs of the product varies little, which can reduce the number and density of the radial ribs, and thus improve the ventilation area under the same conditions.

[0061] Since the area close to the center disc 12 is not a major air outlet area, the above implementation is preferred for the several annular areas close to the outer frame 13 of the guard. The non-major air outlet area close to the center disc 12 can be implemented as above, or according to the prior art, such as the background art or the center disc 12 emitting rays outward, which is not limited here.

[0062] When the radial ribs are arranged sequentially from outside to inside, the radial ribs are arranged in the circular ring area of the outer layer that has not yet been provided with radial ribs; when the radial ribs are arranged sequentially from inside to outside, the radial ribs are arranged in the circular ring area of the inner layer that has not yet been provided with radial ribs; further, if all the base ribs are arranged at one time, the radial ribs can be arranged in the circular ring area that has not yet been provided with radial ribs in any order.

[0063] As shown in Figures 1-4 , the specific steps for arranging a type of radial ribs 10 in step 3 in this embodiment are as follows:

[0064] Step 31: Set the inner circle of the circular ring region where the type of radial ribs 10 is to be arranged as C1, the outer circle as C2, the inner diameter as R1, the outer diameter as R2, the center of the circle as O, m radial ribs are to be arranged, and the shortest distance between optional points on the radial ribs and adjacent radial ribs in the same circular ring region is preset as D.

[0065] In this method, the preset shortest distance D is slightly lower than the design standard. For example, when 12.5 mm in the safety design requirement of the protective cover is selected, the preset shortest distance D can be set to 11.9 mm, which leaves a 5% floating amount relative to 12.5 mm to avoid the influence of errors in design and manufacturing on the quality of subsequent products. The number of radial ribs in the circular ring region can be roughly calculated based on the preset shortest distance D and the inner diameter of the circular ring region. For example, m radial ribs divide the inner diameter into m circular arc segments, and the chord length corresponding to each circular arc segment is greater than or equal to D, thereby obtaining the range of the number of radial ribs. After completing the radial rib arrangement in this circular ring region, the number of radial ribs can be adjusted according to the actual demand for the angle of the radial ribs. After completing the overall arrangement of the radial ribs in the fan protective cover, the number and / or size specifications of the radial ribs can be adjusted according to the overall strength of the fan protective cover.

[0066] The number of radial ribs in the circular ring region can be roughly calculated based on the preset shortest distance D and the inner diameter of the circular ring region. In existing technologies, the shortest distance between adjacent radial ribs gradually increases in the outward diverging direction from the center, so the number is roughly calculated based on the preset shortest distance D and the outer diameter of the circular ring region. Therefore, the number and density of radial ribs are lower in this method, and the effective air outlet area of the fan protective cover is larger.

[0067] Step 32: Uniformly set three first auxiliary ribs 5 with centers O in the circular ring region, which are circles I1, I2, and I3, respectively, and divide the circular ring region into four auxiliary circular ring regions. Draw a radial line from the center O, and draw a radial line from the center O to the outer circle, the inner circle, the first auxiliary rib 5, and the outer circle, which intersect at points A, I1, I2, I3, and B, respectively.

[0068] As shown in Figure 1 , three first auxiliary ribs 5 are uniformly arranged in the annular region where the type of radial ribs 10 is to be arranged. The first auxiliary rib 5 is shown by the dashed line in Figure 1 . The number of first auxiliary ribs 5 is 3 here, and the number of first auxiliary ribs 5 can be adjusted and added according to the precision in implementation.

[0069] Step 33: Calculate the chord length L A , L I1 , L I2 , LI3 , L B .

[0070] Set angle ∠A = acos(D / L A ), ∠I1 = acos(D / L I1 ), ∠I2 = acos(D / L I2 ), ∠I3 = acos(D / L I3 ), ∠B = acos(D / L B );

[0071] In the embodiment, m radial ribs are evenly arranged in the annular region, so each circle is divided into m circular arcs of the same length. Now define the chord length of the divided circular arc as L A , L I1 , L I2 , L I3 , L B .

[0072] L A = 2R1sin(360° / m),

[0073] L I1 = 2(R1+(R2-R1) / 4)sin(360° / m),

[0074] L I2 = 2(R1+2*(R2-R1) / 4)sin(360° / m),

[0075] L I3 = 2(R1+3*(R2-R1) / 4)sin(360° / m),

[0076] L B = 2R2sin(360° / m).

[0077] Step 34, from point A, draw a ray in the direction away from the center O, which forms an angle ∠A with OB; from point I1, draw a ray in the direction away from the center O, which forms an angle ∠I1 with OB; from point I3, draw a ray in the direction away from the center O, which forms an angle ∠I3 with OB; from point B, draw a ray in the direction away from the center O, which forms an angle ∠B with OB; the aforementioned rays are all on the same side of OB.

[0078] Specifically, as shown in FIG. 4, take point A as the starting point, draw a ray a in the direction away from the center O, and the angle between the ray a and the straight line OB is ∠A; Figure 1 Take point I1 as the starting point, draw a ray i1 in the direction away from the center O, and the angle between the ray i1 and the straight line OB is ∠I1;

[0079] Take point I3 as the starting point, draw a ray i3 in the direction away from the center O, and the angle between the ray i3 and the straight line OB is ∠I3;

[0080] Take I2 point as the starting point, and make a ray i2 in the direction away from the center O point. The angle between the ray i2 and the straight line OB is ∠I2;

[0081] Take I3 point as the starting point, and make a ray i3 in the direction away from the center O point. The angle between the ray i3 and the straight line OB is ∠I3;

[0082] Take B point as the starting point, and make a ray i4 in the direction away from the center O point. The angle between the ray i4 and the straight line OB is ∠B.

[0083] The above rays are all located on the same side of OB, which specifically means that the above rays are all on the left side or the right side of OA. In this embodiment, as shown in the figure, Figure 1 the above rays are all on the left side of OA.

[0084] Step 35, in each auxiliary annular region, a second auxiliary muscle 6 with the center O is arranged at the middle position of the auxiliary annular region, the ray with the starting point on the outer circle of the auxiliary annular region is reversely extended to intersect with the second auxiliary muscle 6 in the auxiliary annular region, and the reversely extended ray is rotated around the center O, so that the two rays with the starting points in the same auxiliary annular region all intersect with the second auxiliary muscle 6 in the auxiliary annular region;

[0085] As shown in the figure, Figure 2 three first auxiliary muscles 5 divide four auxiliary annular regions, and the second auxiliary muscle 6 with the center O is arranged at the middle position of the four auxiliary annular regions. The second auxiliary muscle 6 is shown by the middle point dash line. Figure 2

[0086] Now define the second auxiliary muscle 6 located between the circle C1 and the circle I1 as the circle AI1,

[0087] the second auxiliary muscle 6 located between the circle I1 and the circle I2 as the circle I1I2,

[0088] the second auxiliary muscle 6 located between the circle I2 and the circle I3 as the circle I2I3,

[0089] and the second auxiliary muscle 6 located between the circle I3 and the circle C2 as the circle I3B.

[0090] It is easy to obtain that the center of the circle AI1 is O, and the radius is R1+(R2-R1) / 8,

[0091] the center of the circle I1I2 is O, and the radius is R1+3*(R2-R1) / 8,

[0092] the center of the circle I2I3 is O, and the radius is R1+5*(R2-R1) / 8,

[0093] and the center of the circle I3B is O, and the radius is R1+7*(R2-R1) / 8. ​

[0094] To make the two rays with their starting points in the auxiliary circular region intersect on the second auxiliary muscle 6 in the auxiliary circular region, the ray with its starting point on the circle outside the auxiliary circular region is reversely extended to intersect the second auxiliary muscle 6 in the auxiliary circular region.

[0095] As shown in the figure Figure 2 , the ray i1 is reversely extended to intersect the circle AI1,

[0096] the ray i2 is reversely extended to intersect the circle I1I2,

[0097] the ray i3 is reversely extended to intersect the circle I2I3,

[0098] the ray b is reversely extended to intersect the circle I3B.

[0099] Then fix the ray a, and rotate the other rays so that in the four auxiliary circular regions, the two rays with their starting points in the auxiliary circular region intersect on the second auxiliary muscle 6 in the auxiliary circular region.

[0100] As shown in the figure Figure 3 , the reversely extended ray i1 is rotated around the center O so that the reversely extended ray i1 intersects the ray a on the circle AI1,

[0101] Then, the reversely extended ray i2 is rotated around the center O so that the reversely extended ray i2 intersects the ray i1 on the circle I1I2,

[0102] Then, the reversely extended ray i3 is rotated around the center O so that the reversely extended ray i3 intersects the ray i2 on the circle I2I3,

[0103] Then, the reversely extended ray b is rotated around the center O so that the reversely extended ray b intersects the ray i3 on the circle I3B.

[0104] It can be seen from Figure 2 and Figure 3 that in this embodiment, the ray a is fixed, and the rays i1, i2, i3 and b are rotated in turn from inside to outside to meet the above requirements. In specific implementation, it is not limited to which ray is fixed, and the above requirements can be met. Further, an optional point in the auxiliary circular region can be fixed as a point through which the subsequent curve AB passes, and the above requirements can be met by rotating the rays, which will not be specifically shown here.

[0105] Step 36, connect the points A, the intersection points on the above second auxiliary muscle 6 and the point B in turn with smooth curves to form the radial muscle AB, and take the center O as the circle point to array the m radial muscles AB into the circular region.

[0106] Take the center O as the circle point, and the annular array m radial muscle AB to the circular ring area. Thus complete the layout of the radial muscle in the circular ring area.

[0107] According to the above steps, the change of the shortest distance between adjacent radial muscles is small. According to the applicant's practice, when the number of first auxiliary muscles 5 is greater than or equal to 3, the change range of the distance between the radial muscles is less than 5%.

[0108] In specific practice, the number of first auxiliary muscles 5 in step 31 can be increased to further reduce the change range of the above distance. Obviously, the number of second auxiliary muscles 6 depends on the number of first auxiliary muscles 5, and is always one more than the number of first auxiliary muscles 5.

[0109] In some embodiments, the range of the preset curve length L is adjusted according to the curve length L and the actual generated radial muscle AB length to adjust the size of the annular area, that is, to adjust the position of the base muscle 11 in step 36.

[0110] Specifically, in the process of designing from the outside to the inside, that is, designing from the fan protection cover outer frame 13 to the inside, if the length of the curve AB generated in step 36 is greater than the preset curve length L, the position of the base muscle 11 can be adjusted in two ways. Scheme one: select the curve length L value, and confirm the new A point by cutting the curve with a length of L on the curve AB with B as the starting point. The concentric circle where the new A point is located is the adjusted arrangement position of the base muscle 11. Scheme two: expand the radius of the base muscle 11 and repeat step 3 iteration. Scheme one is simpler and more convenient, and scheme two can adjust the number of radial muscles based on the change of the radius of the base muscle 11. The two schemes differ in the generation of different radial muscle inclination angles, which are not limited here, and can be selected according to actual needs or combined with the radial muscle inclination angle in practice.

[0111] Specifically, in the process of designing from the inside to the outside, that is, designing from the center disc 12 to the outside, if the length of the curve AB generated in step 36 is greater than the preset curve length L, since the number of radial muscles arranged in the annular area is determined according to the inner diameter of the circular ring area. Therefore, when designing from the inside to the outside, the newly determined position of the base muscle 11 does not affect the number of radial muscles in the new annular area, and the new B point can be confirmed by cutting the curve with a length of L on the curve AB with A as the starting point. The concentric circle where the new B point is located is the adjusted arrangement position of the base muscle 11.

[0112] At this point, since the position of the foundation ribs 11 needs to be adjusted according to the preset curve length L, the preferred foundation ribs 11 are arranged sequentially from the outer frame 13 of the fan protective cover inwards. This is mainly because the size of the outer frame 13 of the protective cover is determined according to the fan specifications, and a type of radial rib 10 is arranged in the outer ring area. The curve length of the radial ribs has certain requirements, which will affect the layout position of the foundation ribs 11. During the design process, the size of the inner foundation ribs 11 and / or the central disc 12 can still be adjusted. This implementation provides a design margin in the innermost layer and simplifies the design process.

[0113] If an inside-out design method is adopted, the outermost layer cannot meet the curve length requirement. Since the outer frame size is fixed, it is necessary to adjust the already laid-out foundation ribs 11 and radial ribs, iterating the aforementioned design process. Therefore, it is preferable to arrange the foundation ribs 11 sequentially from the outer frame 13 of the wind turbine protective cover inward.

[0114] In some embodiments, the line connecting the start and end points of the radial ribs is AB, and the line connecting the start point of the radial ribs and the center of the circle is OA. The angle range between the lines AB and OA is preset.

[0115] In step 36, while keeping the annular region unchanged, the angle between lines AB and OA can be adjusted by changing the number of radial ribs within the annular region. In practice, a preset angle range can be established based on the characteristics of different fans or the required air outlet angle. It is readily apparent that, with the annular region unchanged, the fewer the radial ribs, the smaller the angle between lines AB and OA corresponding to the generated radial ribs. The number of radial ribs can be iteratively adjusted accordingly to obtain radial ribs that conform to the preset angle range.

[0116] like Figures 5-7 The figure shown is an overall effect diagram of the implementation of the fan protective cover design method provided by the present invention.

[0117] like Figure 5 As shown, in this embodiment, the area between the outer frame 13 of the wind turbine protective cover and the central disk 12 includes four annular regions with radial ribs. Within these four annular regions, a type of radial rib 10 is arranged in the three annular regions closest to the outer frame 13. A type of radial rib satisfies the condition that, at any point on the radial rib, the minimum distance variation between adjacent radial ribs in the same annular region does not exceed 5%.

[0118] That is, in step 3 above, a type of radial rib 10 is arranged in the three annular areas near the outer frame 13 of the protective cover. There are no specific restrictions on other areas; they can be as follows: Figure 5 The arrangement shown can also be other conventional arrangements.

[0119] like Figure 5As shown, the radial ribs directly connected to the center disc 12 are not the first type of radial ribs 10, mainly because the area close to the center disc 12 is not the main air outlet area. In this area, the requirement for the air outlet area is not high, and therefore the first type of radial ribs 10 can be arranged based on aesthetics or other considerations without being limited to the arrangement.

[0120] As shown in the embodiment shown in Figure 5 As shown in the embodiment shown in Figure 6 In the embodiment shown in

[0121] As shown in the embodiment shown in Figure 6 In the embodiment shown in

[0122] That is, in the aforementioned step 3, the first type of radial ribs 10 are arranged in the five annular areas close to the outer frame 13 of the protective cover.

[0123] As is obvious, the number of annular areas in which the first type of radial ribs 10 are arranged is less than or equal to the total number of annular areas. In Figure 5 In the embodiment shown in Figure 6 In the embodiment shown in

[0124] At this time, the base ribs 11 and the radial ribs form a plurality of grids, and the width and the curve length of the grids are substantially the same. Therefore, the strength of the ribs between the grids is substantially the same, and the strength is uniformly distributed, avoiding over-strength of the ribs in some areas. Therefore, under the premise of meeting the strength requirement of the protective cover, the weight of the protective cover can be maximally reduced, and the cost can be reduced.

[0125] As shown in the embodiment shown in Figure 7 As shown in the embodiment shown in Figure 6 The main difference between the embodiment shown in

[0126] As is obvious, in the embodiment shown in Figure 6 In the embodiment shown in Figure 7 In the embodiment shown in

[0127] In the embodiment shown in Figure 6In the fan protection cover, the directions of the radial ribs in different annular regions are the same. Figure 7 In the fan protection cover, the directions of the radial ribs in the innermost layer and other layers are different. In actual use, the air directions in two adjacent regions are different, and the reverse air is mixed, so that the noise during the operation of the fan can be reduced.

[0128] Here, only the result that the rays are located on different sides of OB in different annular regions in step 34 is shown. The radial ribs with different directions are not limited to being arranged in the innermost layer. In the implementation process, adaptive adjustment can be made according to the design process.

[0129] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of designing a fan guard, characterized by, The method comprises the following steps: Step 1, obtaining the size of the fan protective cover outer frame (13), and presetting the size of the center disc (12); Step 2, arranging the base rib (11) between the center disc (12) and the fan protective cover outer frame (13), and forming a plurality of concentric circular ring areas among the center disc (12), the base rib (11) and the fan protective cover outer frame (13); Step 3, arranging the radial rib in the circular ring area to be arranged, and arranging a type of radial rib (10) in a plurality of circular ring areas close to the fan protective cover outer frame (13), wherein the type of radial rib (10) satisfies that the shortest distance between any optional point on the radial rib and the adjacent radial rib in the same circular ring area changes by no more than 5%; The specific steps of arranging the type of radial rib (10) in step 3 are as follows: Step 31, assuming that the inner circle of any circular ring area to be arranged with the type of radial rib (10) is C1, the outer circle is C2, the inner diameter is R1, the outer diameter is R2, the center is O, m radial ribs need to be arranged, and the distance between any optional point on the radial rib and the adjacent radial rib in the same circular ring area is preset as D; Step 32, uniformly arranging s first auxiliary ribs (5) with the center O in the circular ring area, respectively as circles I1, I2, … IS, s is a positive integer greater than or equal to 3, and s+1 auxiliary circular ring areas are divided, and a radial line is drawn from the center O, and the center O is connected to the inner circle, the first auxiliary rib (5) and the outer circle, respectively intersecting at points A, I1, I2, … IS and B; Step 33, respectively calculate the circle C1, I1, I2, … IS, C2 circle center angle is 360° / m corresponding chord length is L A、 L I1、 L I2、… L IS、 L B； Set angle ∠A = a cos (D / L A ), ∠I1 = a cos (D / L I1 ), ∠I2 = a cos (D / L I2 ), … ∠IS = a cos (D / L IS ), ∠B = a cos (D / L B ); Step 34, drawing a radial line from point A in the direction away from the center O and forming an angle A with OB, drawing a radial line from point I1 in the direction away from the center O and forming an angle I1 with OB, drawing a radial line from point I2 in the direction away from the center O and forming an angle I2 with OB, … drawing a radial line from point IS in the direction away from the center O and forming an angle IS with OB, and drawing a radial line from point B in the direction away from the center O and forming an angle B with OB, wherein the aforementioned radial lines are all located on the same side of OB; Step 35, in each auxiliary circular ring area, a second auxiliary rib (6) with the center O is arranged at the middle position of the auxiliary circular ring area, each radial line with the starting point outside the auxiliary circular ring area is reversely extended to intersect with the second auxiliary rib (6) in the auxiliary circular ring area, and the reversely extended radial line is rotated around the center O, so that the two radial lines with the starting point in the same auxiliary circular ring area all intersect with the second auxiliary rib (6) in the auxiliary circular ring area; Step 36, connecting points A, the intersection points on the second auxiliary rib (6) and point B in sequence by a smooth curve to form radial rib AB, and taking the center O as the circle point, and arranging m radial ribs AB in the circular ring area.

2. The fan guard design method of claim 1, wherein Step 36 specifically comprises the following steps: Step 361, connecting points A, the intersection points on the second auxiliary rib (6) and point B in sequence by a smooth curve, and presetting the length L of the curve. Step 362, judging the relationship between the length of the actual curve AB and the preset curve length L, if the length of the curve AB falls within the range of the preset curve length L, executing step 363, if the length of the curve AB does not fall within the range of the preset curve length L, adjusting the position of the base rib so that the length of the curve AB falls within the range of the preset curve length L, and then executing step 363; Step 363, taking the center O as the circle point, and arranging the annular array of m radial ribs AB into the circular ring area.

3. The fan guard design method of claim 1, wherein At least one group of two adjacent circular ring areas is located on different sides of OB in step 34.

4. The fan guard design method of claim 1, wherein Step 36 specifically includes the following steps: Step 36a, connecting the points A, the intersection on the second auxiliary rib (6) and the point B in sequence with a smooth curve, and presetting the angle range between the straight line AB and the straight line OA; Step 36b, judging the relationship between the angle between the straight line AB and the straight line OA and the preset angle range, if the angle between the straight line AB and the straight line OA falls within the preset angle range, executing step 36c, if the angle between the straight line AB and the straight line OA does not fall within the preset angle range, adjusting the number m of radial ribs and returning to step 31 until the angle between the straight line AB and the straight line OA is consistent with the preset range, and then executing step 36c; Step 36c, taking the center O as the circle point, and arranging the annular array of m radial ribs AB into the circular ring area.

5. The fan guard design method of claim 1, wherein The circular ring area to be arranged with the radial rib in step 3 satisfies that the ratio between the outer diameter and the inner diameter is less than 2.

6. The fan guard design method of any of claims 1-5, wherein, The base rib (11) is arranged in step 2 from the outer frame (13) of the fan protective cover inward in sequence.

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