A method of obtaining a torsional break torque for a propeller shaft, a design method, a manufacturing method

Abstract

The present application belongs to the field of aero-engine, and particularly relates to a method for obtaining a torsional rupture torque of a transmission shaft, a design method and a manufacturing method. b W is a tensile strength limit of the transmission shaft material, t W is a torsional section modulus of the transmission shaft, R1 is an inner radius of the transmission shaft, and R2 is an outer radius of the transmission shaft. The method for obtaining the torsional rupture torque of the transmission shaft can not only obtain an accurate torsional rupture torque of the transmission shaft, but also has the advantages of simple method and high efficiency.

Description

Technical Field

[0001] This invention belongs to the field of aero-engines, and specifically relates to a method, design method, and manufacturing method for obtaining the breaking torque of a drive shaft. Background Technology

[0002] With the development of aero-engine structural design technology, drive shaft structural design is pursuing light weight, high reliability and high safety.

[0003] The maximum torque required for the drive shaft to operate without damaging it must be greater than the maximum torque during operation. Therefore, it is very important to obtain the breaking torque in advance for the use, design and manufacturing of drive shafts.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] In order to obtain accurate torsional torque of drive shaft for the design, manufacture and use of drive shaft, this invention proposes a method, design method and manufacturing method for obtaining torsional torque of drive shaft. The method of this invention can not only obtain accurate torsional torque of drive shaft, but also has the advantages of simplicity and high efficiency.

[0006] This invention includes the following technical solutions:

[0007] The first aspect of this invention provides a method for obtaining the breaking torque of a drive shaft, wherein the breaking torque is obtained by the following formula:

[0008] Where: σ b W is the tensile strength limit of the drive shaft material. t R1 is the torsional section modulus of the drive shaft, R2 is the inner radius of the drive shaft, and R2 is the outer radius of the drive shaft.

[0009] Furthermore, the W t It is obtained through the following formula:

[0010] Furthermore, the σ b The method of obtaining it is: to use a tensile testing machine to sample and test the machining blanks generated during the manufacturing process of the drive shaft.

[0011] A second aspect of the present invention provides a method for designing a drive shaft, comprising the following steps:

[0012] A: Determine the breaking torque of the drive shaft;

[0013] B: Utilize the breaking torque from step A, and according to the formula The functional relationship between R1 and R2 is calculated.

[0014] C: Determine the values ​​of R1 and R2 based on the operating environment of the drive shaft and the aforementioned functional relationship;

[0015] Where: σ b W is the tensile strength limit of the drive shaft material. t R1 is the torsional section modulus of the drive shaft, R2 is the inner radius of the drive shaft, and R2 is the outer radius of the drive shaft.

[0016]

[0017] A third aspect of the present invention provides a method for manufacturing a drive shaft, comprising the following steps:

[0018] A: Determine the breaking torque of the drive shaft;

[0019] B: Utilize the breaking torque from step A, and according to the formula The functional relationship between R1 and R2 is calculated.

[0020] C: Determine the values ​​of R1 and R2 based on the operating environment of the drive shaft and the aforementioned functional relationship;

[0021] D: Manufacture the drive shaft based on the obtained values ​​of R1 and R2;

[0022] Where: σ b W is the tensile strength limit of the drive shaft material. t R1 is the torsional section modulus of the drive shaft, R2 is the inner radius of the drive shaft, and R2 is the outer radius of the drive shaft.

[0023]

[0024] Furthermore, when the drive shaft is used as an outer shaft, the value of R1 is first determined based on the fact that R1 is greater than the outer radius of the inner shaft, and finally the value of R2 is calculated based on the functional relationship.

[0025] Furthermore, when the drive shaft is used as an inner shaft, the value of R2 is first determined based on the fact that R2 is less than the inner radius of the outer shaft, and finally the value of R1 is calculated based on the functional relationship.

[0026] Furthermore, when the drive shaft is used in an environment with only one drive shaft, the values ​​of R1 and R2 are determined according to the functional relationship.

[0027] By adopting the above technical solution, the present invention has the following advantages:

[0028] 1. The method for obtaining the torsional torque of a drive shaft according to the present invention can not only obtain accurate torsional torque of the drive shaft, but also has the advantages of being simple and highly efficient.

[0029] 2. The transmission shaft designed by the design method of the transmission shaft has the advantages of light weight, high reliability and high safety.

[0030] 3. The transmission shaft manufactured by the manufacturing method of the transmission shaft has the advantages of light weight, high reliability and high safety.

[0031] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the application. The objects and other advantages of the application can be realized and attained by the structure particularly pointed out in the written description and claims hereof. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0033] Figure 1 The structure schematic diagram of the transmission shaft in the embodiment of the present application;

[0034] Figure 2 The stress-strain curve of the material GH4169 at different temperatures in the embodiment of the present application;

[0035] In the drawings: 10-transmission shaft, 110-transmission shaft outer radius, 120-transmission shaft inner radius. DETAILED DESCRIPTION

[0036] The following description provides many different embodiments, or examples, for implementing different features of the application. Specific examples are described in the following to describe elements and arrangements of the application, which are only used to express the application, and are only examples, not to limit the application.

[0037] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0038] The existing transmission shaft 10 torsional breaking torque calculation method is mainly material mechanics damage stress calculation method, and the method is as follows:

[0039]

[0040] It is believed that under monotonically increasing torque load, when the Von-Mises equivalent stress calculated by the torque and the torsional section modulus of the drive shaft 10 reaches the stress at which a smooth tensile specimen fails, the drive shaft 10 will fail and will no longer be able to withstand the continued increase in torque load.

[0041] The existing evaluation criterion for predicting the torsional moment of the drive shaft 10 is: using the material mechanics failure stress calculation method, when the Von-Mises equivalent stress on the structural surface reaches the stress at which a smooth tensile specimen fails, the drive shaft 10 will experience torsional failure and will no longer have load-bearing capacity. However, in reality, according to typical stress-strain curves of materials, when the stress on the drive shaft 10 exceeds the yield stress, the relationship between stress and strain is no longer linear, and the stress gradient in the radial direction will decrease (i.e., Figure 2 As shown in the curve, the load-bearing capacity of the drive shaft 10 would actually be greater; therefore, the accuracy of the torsional torque obtained by the above method is low.

[0042] Figure 2 The curve in the figure represents the stress-strain curve of material GH4169. The initial section of the curve has a large slope, indicating that under low torque, the stress difference is greater due to the large difference in deformation between the inside and outside of the shaft. The slope of the latter part of the curve is smaller and tends to be flat, indicating that under high torque, although the deformation difference between the inside and outside of the shaft is large, the stress difference is not significant. Of course, the specific material is not limited to GH4169. GH4169 is just an example. Other materials used to manufacture drive shafts, such as 40CrNiMoA, 40CrNi2Si2MoVA, etc., also conform to this principle. Figure 2 The curve shows a regular pattern of change.

[0043] This invention considers that when the stress on the drive shaft 10 reaches the plastic stage, and the overall cross-sectional load-bearing capacity reaches the stress required for the failure of a smooth tensile specimen, the drive shaft 10 will fracture. The formula for calculating the average stress of the cross-section is as follows:

[0044]

[0045] Based on the condition that the average stress at section 10 of the transmission shaft reaches the stress required for the failure of a smooth tensile specimen under torsional moment, the formula for calculating torsional moment can be derived:

[0046]

[0047] Example 1

[0048] This embodiment provides a method for obtaining the torsional moment of a drive shaft, wherein the torsional moment is obtained by the following formula:

[0049] Where: σ bW is the tensile strength limit of the material of drive shaft 10. t R1 is the torsional section modulus of drive shaft 10, R2 is the inner radius of drive shaft 120, and R2 is the outer radius of drive shaft 110.

[0050] σ b The unit is P a W t The unit is m 3 The unit of R1 is meters, the unit of R2 is meters, and T 扭断 The unit is Nm. It should be noted that the formula for calculating the breaking torque is only a numerical calculation.

[0051] The torsional moment obtained by the method of this invention has high accuracy, providing a more precise numerical reference in the design, manufacturing, and use of transmissions. Compared with the methods described above, this invention considers the plastic effect, more realistically simulating the constitutive relationship of the transmission shaft 10 under high stress levels, and effectively improving the accuracy of the torsional moment of the transmission shaft 10.

[0052] Furthermore, the W t It is obtained through the following formula:

[0053] Of course, for others who obtain W t The manner in which this method is used should also be within the scope of protection of this invention.

[0054] Furthermore, the σ b The method of obtaining the sample is as follows: The sample is obtained by sampling and testing the machined blank produced during the manufacturing process of the drive shaft 10 using a tensile testing machine. Testing by sampling the blank has the advantage of high precision, and the blank is generally larger than the drive shaft 10, making sampling and testing feasible. The tensile testing machine and the specific testing process are known to those skilled in the art, and will not be described in detail here.

[0055] Example 2

[0056] This embodiment provides a drive shaft design method, including the method for obtaining the torsional moment of the drive shaft as described in Embodiment 1. The design method includes the following steps:

[0057] A: Determine the breaking torque of the drive shaft 10; this breaking torque is determined by the specific application environment of the drive shaft 10 and the maximum torque it needs to withstand, that is, the breaking torque is greater than the maximum torque that the drive shaft 10 needs to withstand when it is working.

[0058] B: Utilize the breaking torque from step A, and according to the formula The functional relationship between R1 and R2 is calculated.

[0059] C: determining the values of R1 and R2 according to the function relationship and the use environment of the transmission shaft 10;

[0060] wherein: σ b W is the tensile strength limit of the transmission shaft 10 material, W t R1 is the inner radius of the transmission shaft 10, R2 is the outer radius of the transmission shaft 10,

[0061]

[0062] The transmission shaft 10 used in the aero-engine includes single shaft and double shaft. The following provides specific manufacturing methods of several single shafts and double shafts. Of course, the manufacturing method of the transmission shaft 10 of the present application can also be applied to the manufacturing of transmission shafts 10 in other fields.

[0063] Further, when the transmission shaft 10 is the outer shaft (i.e. the manufacturing of the outer shaft of the double shaft transmission shaft), the double shaft needs one transmission shaft 10 to be arranged inside another transmission shaft 10, the transmission shaft 10 inside is the inner shaft, and the transmission shaft 10 outside is the outer shaft. Both of the transmission shafts 10 need to rotate and do not affect each other. According to the function relationship, the value of R1 is determined first, and then the value of R2 is calculated. The outer radius of the inner shaft is a constant, i.e. the inner shaft has been designed or manufactured. Based on this, the transmission shaft 10 can meet the minimum requirement that it will not be twisted off at the maximum torque, and has the advantages of light weight, high reliability and high safety.

[0064] Further, when the transmission shaft 10 is the inner shaft (i.e. the manufacturing of the inner shaft of the double shaft transmission shaft), according to the function relationship, the value of R2 is determined first, and then the value of R1 is calculated. The inner radius of the outer shaft is a constant, i.e. the inner shaft has been designed or manufactured. The transmission shaft 10 can meet the minimum requirement that it will not be twisted off at the maximum torque, and has the advantages of light weight, high reliability and high safety.

[0065] Further, when there is only one transmission shaft 10 (i.e. the manufacturing of the single shaft transmission shaft), after obtaining the function relationship of R1 and R2, the values of R1 and R2 need to be determined respectively. Since the single shaft does not need to arrange another transmission shaft 10 in the middle or outside of the transmission shaft 10, it can be designed as a solid transmission shaft 10, i.e. R1 = 0, and the corresponding value of R2 can be obtained. The transmission shaft 10 can meet the minimum requirement that it will not be twisted off at the maximum torque, and has the advantages of light weight, high reliability and high safety.

[0066] Example 3

[0067] The embodiment provides a transmission shaft manufacturing method, including a method for obtaining a torsional rupture torque of the transmission shaft, and the manufacturing method comprises the following steps:

[0068] A: determining the torsional rupture torque of the transmission shaft 10; the torsional rupture torque is determined by an environment in which the transmission shaft 10 is specifically applied and a maximum torque to be borne, that is, the torsional rupture torque is greater than a maximum torque to be borne by the finally obtained transmission shaft 10 when the transmission shaft 10 works;

[0069] B: using the torsional rupture torque in step A and according to a formula to calculate a function relationship formula of R1 and R2;

[0070] C: determining the values of R1 and R2 according to the function relationship formula and the use environment of the transmission shaft 10;

[0071] D: manufacturing the transmission shaft 10 according to the obtained values of R1 and R2;

[0072] Wherein: sigma b is a tensile strength limit of the transmission shaft 10, W t is a torsional section modulus of the transmission shaft 10, R1 is an inner radius 120 of the transmission shaft, and R2 is an outer radius 110 of the transmission shaft,

[0073] The transmission shaft manufactured by the transmission shaft manufacturing method has the advantages of light weight, high reliability and high safety.

[0074] The transmission shaft 10 used in an aero-engine includes a single shaft and a double shaft, and specific manufacturing methods of several single shafts and double shafts are provided below. Of course, the transmission shaft 10 manufacturing method of the present application can also be applied to the manufacturing of transmission shafts 10 in other fields.

[0075] Further, when the transmission shaft 10 is an outer shaft (that is, the manufacturing of an outer shaft of a double shaft transmission shaft), the double shaft is required to be arranged in another transmission shaft 10, the transmission shaft 10 located inside is an inner shaft, the transmission shaft 10 located outside is an outer shaft, both the transmission shafts 10 need to rotate and do not affect each other; the value of R1 is determined first according to that R1 is greater than the outer radius of the inner shaft, and finally the value of R2 is calculated according to the function relationship formula. The outer radius of the inner shaft is a constant, that is, the inner shaft has been designed or manufactured. The transmission shaft 10 can be the smallest on the basis of not being twisted off at the maximum torque, and has the advantages of light weight, high reliability and high safety.

[0076] Further, when the transmission shaft 10 is an inner shaft (i.e. manufacturing of an inner shaft of a double shaft transmission shaft), the value of R2 is determined according to the function relationship of R2 < the inner radius of the outer shaft, and then the value of R1 is calculated according to the function relationship. The inner radius of the outer shaft is a constant, i.e. the inner shaft has been designed or manufactured. The transmission shaft 10 can meet the minimum requirement of not being broken under the maximum torque, and has the advantages of light weight, high reliability and high safety.

[0077] Of course, the inner shaft and the outer shaft in the above method can also be designed and manufactured according to the method of the present application, but finally four variables need to be determined at the same time, and the calculation is relatively more complex, but it can be realized by those skilled in the art.

[0078] Further, when there is only one transmission shaft 10 (i.e. manufacturing of a single shaft transmission shaft), after obtaining the function relationship of R1 and R2, the values of R1 and R2 need to be determined respectively. Since the single shaft does not need to set another transmission shaft 10 in the middle or outside of the transmission shaft 10, the transmission shaft 10 can be designed as a solid transmission shaft 10, i.e. R1 = 0, and the corresponding value of R2 can be obtained. At this time, the transmission shaft 10 can meet the minimum requirement of not being broken under the maximum torque, and has the advantages of light weight, high reliability and high safety.

[0079] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of obtaining a torque to break a propeller shaft, characterized in that, The torsional break torque is obtained by the following formula: ; wherein: is the tensile strength limit of the material of the propeller shaft, is the torsional section modulus of the propeller shaft, is the inner radius of the propeller shaft, is the outer radius of the propeller shaft; in units of , in units of , in units of , in units of , in units of .

2. A method of obtaining a torsional break torque for a propeller shaft as claimed in claim 1, characterised in that, The is obtained by the following equation: .

3. The method of claim 1, wherein, The The way to obtain is: with tensile testing machine to the transmission shaft manufacturing process generated by sampling test processing blank.

4. A method of designing a propeller shaft, characterized by Comprising the steps of: A: determining the torsional break torque of the propeller shaft; B: Using the torsional moment of step A, and according to the formula the function relationship of and is calculated C: determining the value of the function relationship according to the use environment of the transmission shaft and the function relationship and the value of the function relationship. wherein: is the tensile strength limit of the material of the propeller shaft, is the torsion section modulus of the propeller shaft, is the inner radius of the propeller shaft, is the outer radius of the propeller shaft, .

5. A method of manufacturing a propeller shaft, characterized by Comprising the steps of: A: determining the torsional break torque of the propeller shaft; B: Using the torsional moment of step A, and according to the formula the function relationship of and is calculated C: determining the value of the function relationship according to the use environment of the transmission shaft and the function relationship and the value of the function relationship D: manufacture the propeller shaft according to the values obtained and values. wherein: is the tensile strength limit of the material of the propeller shaft, is the torsion section modulus of the propeller shaft, is the inner radius of the propeller shaft, is the outer radius of the propeller shaft, .

6. A method of manufacturing a propeller shaft according to claim 5, wherein, The use environment of the transmission shaft is that the transmission shaft is an outer shaft, according to The outer radius of the shaft is greater than the inner shaft The value of the outer radius of the shaft is greater than the inner shaft The value of the outer radius of the shaft is greater than the inner shaft 7. A method of manufacturing a propeller shaft according to claim 5, wherein The use environment of the transmission shaft is that the transmission shaft is an inner shaft, according to The inner radius of the shaft smaller than the outer shaft is determined first The value of the function relationship formula is calculated finally .

8. A method of manufacturing a propeller shaft according to claim 5, wherein, The use environment of the transmission shaft is only one transmission shaft, and the value of the function relationship is determined according to the function relationship and .

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