Fuel gear pump design method based on precise flow model
By constructing an accurate flow model for the fuel gear pump, the problem of large flow calculation deviations in traditional design methods was solved, enabling accurate design under high pressure and high flow conditions and meeting the high-performance requirements of aero-engine fuel systems.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-03
AI Technical Summary
Traditional fuel gear pump design methods based on empirical formulas suffer from significant discrepancies between theoretical flow calculations and actual operating conditions when dealing with high-pressure, high-flow-rate conditions, thus affecting design accuracy.
Based on a precise flow model, the instantaneous flow equation of a fuel gear pump is constructed by analyzing the design principle of involute gears. By combining the gear meshing principle and kinematic characteristics, gear parameters are optimized to ensure the accuracy of flow calculation.
It achieves precise matching between the theoretical flow calculation value and the actual operating condition of the fuel gear pump under extreme conditions, meets the design requirements of large flow demand, and improves design accuracy.
Smart Images
Figure CN121787008A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fuel gear pump technology for aero-engines, and in particular to a fuel gear pump design method based on an accurate flow model. Background Technology
[0002] Involute gear pumps, due to their compact structure, strong anti-pollution capability, and high reliability, have become a key power component of the main fuel system of aero-engines. With the rapid development of modern aviation technology, the new generation of aero-engines places higher demands on power density and energy conversion efficiency, directly driving technological innovation in fuel gear pumps towards higher pressure, higher speed, and larger flow rates. However, traditional design methods based on empirical formulas have significant shortcomings in dealing with these extreme operating conditions. The most prominent problem is a 15%-20% deviation between theoretical flow rate calculations and actual operating conditions, which seriously affects the design accuracy of high-pressure, high-flow pumps. Against this backdrop, conducting research on the accurate derivation of the theoretical flow rate of fuel gear pumps is of significant engineering importance. By deeply analyzing the fuel supply mechanism of involute fuel gear pumps and systematically examining the influence of key factors such as tooth profile parameters and rotational speed on the theoretical flow rate, a solid theoretical foundation will be laid for the development of high-performance, high-flow fuel gear pumps. Summary of the Invention
[0003] To overcome the above technical problems, the present invention aims to provide a fuel gear pump design method based on a precise flow model. By analyzing the design principle of involute gears, starting from the characteristics of the involute, and based on the gear meshing geometry, the variation law of the area swept by the gear teeth during the operation of the gear pump is obtained. The entire meshing process is decomposed into microscales, and based on the volumetric flow rate of the oil discharged by the meshing gears in an infinitesimal time, the instantaneous flow equation is obtained. Combining the gear meshing principle, a precise flow model of the fuel gear pump is constructed. Based on this model, the parameters of each gear tooth are calculated, and the design of the fuel gear pump based on the precise flow model is completed.
[0004] The technical solution adopted in this invention is: A design method for a fuel gear pump based on an accurate flow model includes the following steps; Step 1: Calculate the involute characteristics of the gear tooth profile curve; obtain the area of the oil-containing region and its variation law when the driving and driven gears rotate; Step 2: The oil containment area is micro-divided based on the gear meshing process, and the instantaneous flow equation of the fuel gear pump is constructed by combining the gear pump geometry and kinematic characteristics. Step 3: Based on the gear meshing principle, determine the effective working range of the gear teeth, describe the oil delivery law of the gear pump during the entire meshing period based on the instantaneous flow equation, and obtain the accurate flow equation of the fuel gear pump. Step 4: Based on the accurate flow model, the gear module is calculated considering the influence of parameters such as rotational speed and number of teeth, thereby completing the design of the fuel gear pump.
[0005] Step one specifically involves: The driving and driven gears of the aviation fuel gear pump are involute gears; 1) Property 1: The area formed by the involute, the tangent line from any point on the involute to the base circle, and the arc between the starting point of the involute and the resulting point of tangency is equal to the area defined by the formula... The calculated value; by Indicates the base circle radius. The starting point of the involute, The endpoint of the involute. For any point on the involute, For the reason Draw a tangent line to the base circle at the corresponding point of tangency, and calculate... , The distance between the points is , for The corresponding vector radius, For the reason If we draw a tangent line to the base circle at the corresponding point of tangency, then we have: (1) Therefore there is and Then we have: (2) In a right triangle In the middle, by the Pythagorean theorem, we get: (3) Record the area of the shaded area for Its calculation can be performed using the following equation: (4) Combining equations (2), (3), and (4), we have: (5) According to geometric relationships, the area... equal to area With area difference, From involute, radius ,radius and tangents Enveloped; The area described in Feature 1 corresponds to the area in the diagram. , recorded as It can be expressed as area. With sector area The difference is that , And because of the area , , Therefore, it is possible ,again Therefore, we can conclude that: (6) That is, the area formed by the involute, the tangent line from any point on the involute to the base circle, and the arc between the starting point of the involute and the resulting point of tangency is equal to... ; In the above formula, The radius of the base circle, for Corresponding angle, for Corresponding angle, for Corresponding angle, for Corresponding angle, This is the distance from the point of meshing to the center of the gear; The area formed by the two involutes, the base circle arcs corresponding to the origins of these two involutes, and the arcs concentric with the base circle is denoted as . Draw radii from the endpoints of the arcs concentric with the base circle toward the center of the base circle, intersecting the base circle at two points, forming a base circle arc. The area enclosed by the outer arc, the two radii, and the base circle arc is denoted as . ; , ,remember , , If there is such a thing, then there is such a thing. , According to geometric relationships, since and The corresponding angles are the same, all of them are Therefore, In summary: (7) In the above formula, The radius of the top circle is 1. The radius of the base circle, for Corresponding angle; Step two specifically involves: In an infinitesimal time Internal, instantaneous flow rate of gear pump The tooth profiles of the meshing gears in contact within an infinitesimal time The calculation is based on the volume of oil squeezed out from the inside; Take gear teeth The time of point contact is the initial instant. ,Should Points and nodes The distance between them is Let the distance from a point on the meshing line to the node be defined, with positive values to the right of the node and negative values to the left. Then we have: At this point, the tooth profile of the driving gear is at the right vertex of the driving gear tooth tip. Contact point with gear teeth and the intersection of the tooth profile of the driving gear and the base circle of the driven gear. The curves formed ,by This indicates that the tooth profile of the driven gear is located at the left vertex of the tooth tip. Contact point with gear teeth and the intersection of the driven gear tooth profile and the base circle of the driving gear. The curves formed ,by express; When the gear pump rotates at an infinitesimal angle Then, the tooth profile of the driving gear is located at the right vertex of the driving gear tooth tip. Contact point with gear teeth and the intersection of the tooth profile of the driving gear and the base circle of the driven gear. The curves formed The tooth profile of the driven gear is located at the left vertex of the tooth tip. Contact point with gear teeth and the intersection of the driven gear tooth profile and the base circle of the driving gear. The curve formed = Their meshing occurs Point, this point and The distance between points is ,exist The volume of oil squeezed out by the meshing of the gear teeth within a certain time is equal to the curve. and curve The area of the shadow between the teeth multiplied by the tooth width : (8) But area It can be considered as area and The difference, based on the above derivation process of the involute, is: (9) against Its area is equal to its area and area The difference, and the area and area It is made by tangent and Base circle arc and And in involute of an angle and in involute of an angle What constitutes, in order to The calculation formula, after discarding the infinite decimal term, is transformed as follows: (10) Substituting equations (9) and (10) into equation (8), we get: (11) Similarly, area Area can also be used and area The difference is obtained from the above. and The calculation process yields the following results: (12) horn and The relationship is derived as follows: According to geometric relationships, the length of the meshing line is: (13) From this we can obtain Therefore , will corner and Relational substitution The calculation formula may include: (14) Combining equation (12) and equation (14), we can obtain: (15) The result , Add and substitute After simplifying the calculation formula, we have: (16) And because of the pitch circle radius Therefore ,again Then there may be Solving for ; Substituting the value obtained above into equation (16), we get: (17) In equation (17) by Instead, by This allows us to obtain the instantaneous flow equation: (18) Step three specifically involves: Integrate equation (18); If the oil pump is not equipped with any unloading device, connect the sealed chamber to the suction line, and use... Let AC represent the length of the working portion of the meshing line, thus the integral limit of equation (18) is: ,in Let be the pitch. Therefore, integrating equation (18) yields: (19)
[0006] And because of the overlap ratio and Then, by changing equation (19), we get: (20) in .
[0007] To calculate the theoretical flow rate of the entire fuel gear pump, the number of teeth must be taken into account. and rotational speed Then multiply equation (20) by and We can obtain: (twenty one) Equation (21) is the general equation for the accurate flow rate of an involute gear pump; For a gear pump with a tooth profile where the addendum is equal to the module m (i.e., the addendum coefficient is 1), its , , At this point, equation (21) can be transformed into: (twenty two) Equations (21) and (22) above can be simplified to: (twenty three)
[0008] (twenty four) Step four specifically involves: Given the actual flow rate of the fuel gear pump At that time, according to the theoretical flow rate Compared with actual traffic Relationship , For the efficiency of the fuel gear pump and equation (24), take... We can obtain: (25) Tooth tip linear velocity The unit is ,again Then there may be ,Will Substituting the expression into equation (25), we get: (26) For fuel gear pumps, the number of teeth The range of variation is Therefore, the ratio In The value varies within a certain range, and its average value is taken as 0.84. The value is 0.85, therefore: (27) The gear is designed to be filled with oil, and the circumferential speed of the gear is... Within the range, the formula for calculating the modulus is: (28) The beneficial effects of this invention are: This invention addresses the high flow rate requirements of fuel gear pumps and leverages the geometric characteristics of involute tooth profiles. It calculates the swept area of the tooth profile using coordinate transformation and integration methods. The shape of the involute is determined by the base circle radius and pressure angle. As the gear rotates, the contact point between the tooth surface and the meshing line dynamically changes, forming the boundary of the oil containment area. This process requires precise analysis of the tooth root transition curve and meshing point trajectory to determine the physical range within which the oil is sealed, transported, and released. To achieve accurate flow rate calculation, the oil containment area needs to be decomposed into minute units. A dynamic coordinate system is established by combining the gear pair's rotational speed and center distance to describe the instantaneous changes in the inter-tooth volume, ensuring the accuracy of flow rate prediction. Based on the gear meshing principle, the effective working range of the teeth is determined, and the gear pump's oil delivery pattern during the entire meshing period is described based on the instantaneous flow rate equation, thus yielding the accurate flow rate equation for the fuel gear pump. Gear parameter optimization is performed based on an accurate flow model. While meeting the rated flow requirements, key parameters such as gear module, number of teeth, and tooth width are rationally selected by comprehensively considering tooth root bending strength and contact fatigue life. This effectively solves the problem of large deviations between theoretical flow calculations and actual operating conditions in fuel gear pumps under extreme conditions, providing an effective solution for designing fuel gear pumps to meet high flow requirements. Attached image description: Figure 1 This is a flowchart of the technology of the present invention.
[0009] Figure 2 This is a schematic diagram of the involute characteristic 1 of the present invention.
[0010] Figure 3 This is a schematic diagram of the involute characteristic 2 of the present invention.
[0011] Figure 4 This is a schematic diagram illustrating the theoretical flow rate derivation of this invention.
[0012] Figure 5 This is a three-dimensional model of the fuel gear pump of the present invention. Detailed Implementation
[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0014] like Figure 1 As shown, the first part: derives the characteristics of the involute curve, providing a theoretical basis for determining the oil containment area and calculating the area swept by the tooth profile.
[0015] The driving and driven gears of aviation fuel gear pumps are generally involute gears, and the study of involute characteristics is the basis for constructing accurate flow models.
[0016] 1) Property 1: The area formed by the involute, the tangent line from any point on the involute to the base circle, and the arc between the starting point of the involute and the resulting point of tangency is equal to the area defined by the formula... The calculated value.
[0017] As shown in Figure 2, with Indicates the base circle radius. The starting point of the involute, The endpoint of the involute. For any point on the involute, For the reason Draw a tangent line to the base circle at the corresponding point of tangency, and calculate... , The distance between the points is , for The corresponding vector radius, For the reason Draw a tangent line to the base circle at the corresponding point of tangency. Then we have: (1) Therefore there is and Then we have: (2) In a right triangle In the middle, by the Pythagorean theorem, we get: (3) Record the shaded area in Figure 2. for Its calculation can be performed using the following equation: (4) Combining equations (2), (2), and (4), we have: (5) According to the geometric relationships in Figure 2, the area... equal to area With area difference, From involute, radius ,radius and tangents Enveloped. The area described in characteristic 1 corresponds to the area in the diagram. , recorded as It can be expressed as area. With sector area The difference is that , And because of the area , , Therefore, it is possible ,again Therefore, we can conclude that: (6) That is, the area formed by the involute, the tangent line from any point on the involute to the base circle, and the arc between the starting point of the involute and the resulting point of tangency is equal to... .
[0018] In the above formula, The radius of the base circle, for Corresponding angle, for Corresponding angle, for Corresponding angle, for Corresponding angle, This is the distance from the point of meshing to the center of the gear.
[0019] The area formed by the two involutes, the base circle arcs corresponding to the origins of these two involutes, and the arcs concentric with the base circle is denoted as . Draw radii from the endpoints of the arcs concentric with the base circle toward the center of the base circle, intersecting the base circle at two points, forming a base circle arc. The area enclosed by the outer arc, the two radii, and the base circle arc is denoted as . .
[0020] As shown in Figure 3 , ,remember , , If there is such a thing, then there is such a thing. , However, according to geometric relationships, since and The corresponding angles are the same, all of them are Therefore, In summary: (7) In the above formula, The radius of the top circle is 1. The radius of the base circle, for Corresponding angle.
[0021] Part Two: Constructing the instantaneous flow equation of the fuel gear pump to describe the instantaneous variation of the inter-gear fuel supply law; In an infinitesimal time Internal, instantaneous flow rate of gear pump The tooth profiles of the meshing gears can be used in an infinitesimal time. The calculation is based on the volume of oil squeezed out from inside.
[0022] As shown in Figure 4, take the gear teeth at... The time of point contact is the initial instant. ,Should Points and nodes The distance between them is (We put the one on the right of the node) (Set to positive). At this time, the tooth profile position of the driving gear is... ,by This indicates that the tooth profile of the driven gear is... ,by express.
[0023] When the gear pump rotates at an infinitesimal angle Afterwards, the tooth profile position of the driving gear is... The tooth profile of the driven gear is as follows: At the same time, their meshing occurs Point, this point and The distance between points is .exist The volume of oil squeezed out by the meshing of the gear teeth within a certain time is equal to the curve. and curve The area of the shadow between the teeth multiplied by the tooth width : (8) But area It can be considered as area and The difference, based on the above derivation process of the involute, is: (9) against Its area is equal to its area and area The difference, and the area and area It is made by tangent and Base circle arc and And in involute of an angle and in involute of an angle What constitutes, in order to The calculation formula, after discarding the infinite decimal term, is transformed as follows: (10) Substituting equations (9) and (10) into equation (8), we get: (11) Similarly, area Area can also be used and area The difference is obtained from the above. and The calculation process yields the following results: (12) horn and The relationship is derived as follows: From the geometric relationship in Figure 4, the length of the meshing line is: (13) From this we can obtain Therefore . (The corner) and Relational substitution The calculation formula may include: (14) Combining equation (12) and equation (14), we can obtain: (15) The result , Add and substitute After simplifying the calculation formula, we have: (16) And because of the pitch circle radius Therefore ,again Then there may be Solving for .
[0024] Substituting the value obtained above into equation (16), we get: (17) In equation (17) by Instead, by This allows us to obtain the instantaneous flow equation: (18) Part Three: Constructing the precise flow equation for the fuel gear pump to describe the fuel delivery pattern of the gear pump throughout the entire meshing period.
[0025] Based on the derivation of the instantaneous flow equation above, in order to calculate the flow rate of a pair of gear teeth during the entire meshing process, equation (18) must be integrated.
[0026] As shown in Figure 4, if the oil pump is not equipped with any unloading device and the enclosed cavity is connected to the suction line, the following effect will occur: during the meshing of a pair of gear teeth from point B to point C, the liquid will flow backwards towards the suction line. In this case, the effective operation of the gears occurs during the meshing period from point A to point B, that is, from the start of its meshing to the start of the meshing of the next pair of gear teeth. Let AC represent the length of the working portion of the meshing line, thus the integral limit of equation (18) is: ,in Let be the pitch. Therefore, integrating equation (18) yields: (19) And because of the overlap ratio and Then, by changing equation (19), we get: (20) in .
[0027] To calculate the theoretical flow rate of the entire fuel gear pump, the number of teeth must be taken into account. and rotational speed Then multiply equation (20) by and We can obtain: (twenty one) Equation (21) is the general equation for the accurate flow rate of an involute gear pump.
[0028] For a gear pump with a tooth profile where the addendum is equal to the module m (i.e., the addendum coefficient is 1), its , , At this point, equation (21) can be transformed into: (twenty two) Furthermore, considering that the commonly used range of tooth counts for fuel gear pumps is... ,but The average value is close to 1.2, so the above equations (21) and (22) can be simplified as follows: (twenty three) (twenty four) Part Four: Based on the accurate flow model, the gear module was calculated to determine the key tooth profile parameters, laying the foundation for the subsequent design of the fuel gear pump.
[0029] Given the actual flow rate of the fuel gear pump At that time, according to the theoretical flow rate Compared with actual traffic Relationship , For the efficiency of the fuel gear pump and equation (24), take... We can obtain: (25) Tooth tip linear velocity The unit is ,again Then there may be ,Will Substituting the expression into equation (25), we get: (26) For fuel gear pumps, the number of teeth The range of variation is Therefore, the ratio In The value varies within a certain range, and its average value is taken as 0.84. The value is 0.85, thus we get: (27) The gear is designed to be filled with oil, and the circumferential speed of the gear is... Within the range, the formula for calculating the modulus is: (28) Part 5: Examples The advantages of this invention can be further illustrated by the following design examples. Design Specifications The given design parameters are shown in Table 1. The physical properties of the selected oil are shown in Table 2.
[0030] Table 1 Design Requirements for Gear Pumps
[0031] Table 2 Oil physical properties
[0032] Design Results As shown in Table 1 Therefore, according to equation (28), we can obtain: (29) Take the modulus The remaining gear pump parameters were determined based on other design parameters, and the results are shown in Table 3. Table 3 Gear Parameters
[0033] Based on the above gear parameter calculation results, a 3D model of the fuel gear pump was created in UG as shown in Figure 5.
Claims
1. A design method for a fuel gear pump based on a precise flow model, characterized in that, Includes the following steps; Step 1: Calculate the involute characteristics of the gear tooth profile curve; obtain the area of the oil-containing region and its variation law when the driving and driven gears rotate; Step 2: The oil containment area is micro-divided based on the gear meshing process, and the instantaneous flow equation of the fuel gear pump is constructed by combining the gear pump geometry and kinematic characteristics. Step 3: Based on the gear meshing principle, determine the effective working range of the gear teeth, describe the oil delivery law of the gear pump during the entire meshing period based on the instantaneous flow equation, and obtain the accurate flow equation of the fuel gear pump. Step 4: Based on the accurate flow model, calculate the gear module considering the influence of parameters such as rotational speed and number of teeth, and complete the design of the fuel gear pump.
2. The fuel gear pump design method based on a precise flow model according to claim 1, characterized in that, Step one specifically involves: The driving and driven gears of the aviation fuel gear pump are involute gears; 1) Property 1: The area formed by the involute, the tangent line from any point on the involute to the base circle, and the arc between the starting point of the involute and the resulting point of tangency is equal to the area defined by the formula... The calculated value; by Indicates the base circle radius. The starting point of the involute, The endpoint of the involute. For any point on the involute, For the reason Draw a tangent line to the base circle at the corresponding point of tangency, and calculate... , The distance between the points is , for The corresponding vector radius, For the reason If we draw a tangent line to the base circle at the corresponding point of tangency, then we have: (1) Therefore there is and Then we have: (2) In a right triangle In the middle, by the Pythagorean theorem, we get: (3) Record the area of the shaded area for Its calculation can be performed using the following equation: (4) Combining equations (2), (3), and (4), we have: (5) According to geometric relationships, the area... equal to area With area difference, From involute, radius ,radius and tangents Enveloped; The area described in Feature 1 corresponds to the area in the diagram. , recorded as It is expressed as area With sector area The difference is that , ,area , , Therefore, ,again Therefore, we can conclude that: (6) In the above formula The shaded area in the figure ; The area in the figure , composed of involute, radius ,radius and tangents Enveloped; The area in the figure ; The area in the figure ; The area in the figure ; That is, the area formed by the involute, the tangent line from any point on the involute to the base circle, and the arc between the starting point of the involute and the resulting point of tangency is equal to... ; In the above formula, The radius of the base circle, for Corresponding angle, for Corresponding angle, for Corresponding angle, for Corresponding angle, This is the distance from the point of meshing to the center of the gear; The area formed by the two involutes, the base circle arcs corresponding to the origins of these two involutes, and the arcs concentric with the base circle is denoted as . Draw radii from the endpoints of the arcs concentric with the base circle toward the center of the base circle, intersecting the base circle at two points, forming a base circle arc. The area enclosed by the outer arc, the two radii, and the base circle arc is denoted as . ; , ,remember , , If there is such a thing, then there is such a thing. , According to geometric relationships, since and The corresponding angles are the same, all of them are Therefore, In summary: (7) In the above formula, The radius of the top circle is 1. The radius of the base circle, for Corresponding angle; In the above formula The area in the figure ; The area in the figure ; The area in the figure ; The area in the figure ; The area in the figure .
3. The fuel gear pump design method based on a precise flow model according to claim 1, characterized in that, Step two specifically involves: In an infinitesimal time Internal, instantaneous flow rate of gear pump The tooth profiles of the meshing gears in contact within an infinitesimal time The calculation is based on the volume of oil squeezed out from the inside; Take gear teeth The time of point contact is the initial instant. ,Should Points and nodes The distance between them is Let the distance from a point on the meshing line to the node be defined, with positive values to the right of the node and negative values to the left. Then we have: At this point, the tooth profile of the driving gear is at the right vertex of the driving gear tooth tip. Contact point with gear teeth and the intersection of the tooth profile of the driving gear and the base circle of the driven gear. The curve formed ,by This indicates that the tooth profile of the driven gear is located at the left vertex of the tooth tip. Contact point with gear teeth and the intersection of the driven gear tooth profile and the base circle of the driving gear. The curve formed ,by express; When the gear pump rotates at an infinitesimal angle Afterwards, the tooth profile of the driving gear is located at the right vertex of the driving gear tooth tip. Contact point with gear teeth and the intersection of the tooth profile of the driving gear and the base circle of the driven gear. The curve formed The tooth profile of the driven gear is located at the left vertex of the tooth tip. Contact point with gear teeth and the intersection of the driven gear tooth profile and the base circle of the driving gear. The curve formed Their meshing occurs Point, this point and The distance between points is ,exist The volume of oil squeezed out by the meshing of the gear teeth within a certain time is equal to the curve. and curve The area of the shadow between the teeth multiplied by the tooth width : (8) area It is the area and The difference, based on the above derivation process of the involute, is: (9) against Its area is equal to its area and area The difference, and the area and area It is the tangent and Base circle arc and And in involute of an angle and in involute of an angle What constitutes, in order to The calculation formula, after discarding the infinite decimal term, is transformed as follows: (10) Substituting equations (9) and (10) into equation (8), we get: (11) Similarly, area Area can also be used and area The difference is obtained from the above. and The calculation process yields the following results: (12) horn and The relationship is derived as follows: According to geometric relationships, the length of the line of engagement is: (13) From this we can obtain Therefore , will corner and Relational substitution The calculation formula may include: (14) Combining equation (12) and equation (14), we can obtain: (15) The result , Add and substitute After simplifying the calculation formula, we have: (16) And because of the pitch circle radius Therefore ,again Then there may be Solving for ; Substituting the value obtained above into equation (16), we get: (17) In equation (17) by Instead, by This allows us to obtain the instantaneous flow equation: (18)。 4. The fuel gear pump design method based on a precise flow model according to claim 1, characterized in that, Step three specifically involves: Integrate equation (18); If the oil pump is not equipped with any unloading device, connect the sealed chamber to the suction line, and use... Let AC represent the length of the working portion of the meshing line, thus the integral limit of equation (18) is: ,in Let be the pitch. Therefore, integrating equation (18) yields: (19) And because of the overlap ratio and Then, by changing equation (19), we get: (20) in ; Multiply equation (20) by and We can obtain: (21) Equation (21) is the general equation for the accurate flow rate of an involute gear pump; For a gear pump with a tooth profile where the addendum is equal to the module m (i.e., the addendum coefficient is 1), its , , At this point, equation (21) transforms into: (22) The above equations (21) and (22) can be simplified to: (23) (24)。 5. The fuel gear pump design method based on a precise flow model according to claim 1, characterized in that, Step four specifically involves: Given the actual flow rate of the fuel gear pump At that time, according to the theoretical flow rate Compared with actual traffic Relationship , For the efficiency of the fuel gear pump and equation (24), take... We can obtain: (25) Tooth tip linear velocity The unit is ,again Then there is ,Will Substituting the expression into equation (25), we get: (26) For fuel gear pumps, number of teeth The range of variation is Therefore, the ratio In The value varies within a certain range, and the average value is taken as 0.
84. The value is 0.85, therefore: (27) The gear is designed to be filled with oil, and the circumferential speed of the gear is... Within the range, the formula for calculating the modulus is: (28)。