Commercial vehicle four-wheel drive transmission shaft, type selection matching method thereof and storage medium

Abstract

The invention discloses a commercial vehicle four-wheel drive transmission shaft, a model selection matching method thereof and a storage medium. The method comprises the steps that basic parameters are obtained; according to the obtained basic parameters, combining with chassis arrangement, considering limit axle load transfer and taking a mass center as a zero point to establish a whole vehicle moment balance formula under different limit working conditions; according to the whole vehicle moment balance formula, the dynamic axle load of the front axle and the dynamic axle load of the rear axle under the limit axle load transfer condition of the corresponding limit working conditions are obtained, so that the maximum torque actually borne by each section of transmission shaft under the different limit working conditions is obtained; and through the obtained maximum torque value borne by each section of transmission shaft under the working conditions of full accelerator acceleration under four-wheel drive and two-wheel drive and retreating limit axle load transfer, and selecting the maximum value of the maximum torque value borne by each section of transmission shaft as the actual torque minimum value of the type selection of each section of transmission shaft, the type selection of the transmission shaft is realized. According to the method, the appropriate transmission shaft specification is selected through theoretical calculation close to reality, the cost of the whole vehicle is reduced, and the safety of the whole vehicle is improved.

Description

Technical Field

[0001] The present invention relates to the field of commercial vehicle drive technology, in particular to a commercial vehicle four-wheel drive transmission shaft, a selection and matching method thereof, and a storage medium. Background Art

[0002] During the vehicle development and design phase of existing commercial vehicles, for four-wheel drive vehicles, the maximum torque that each of the three drive shafts can withstand must be tested separately to match the appropriate drive shaft resources and avoid wasting resources or insufficient torque.

[0003] Typically, the maximum torque applied by the drive system to the drive shaft and the maximum adhesion torque provided by the ground during tire slip are measured. The minimum torque is then compared to determine the maximum torque applied to the drive shaft and the maximum adhesion torque provided by the ground. When measuring ground adhesion torque during tire slip, the product of the static axle load and the ground adhesion coefficient is generally used. Because axle load transfer occurs during vehicle acceleration and deceleration due to inertia, the front and rear axle loads in actual operating conditions may differ from those at static conditions. This can cause a discrepancy between the measured maximum torque and the actual torque, making it impossible to match the appropriate drive shaft resources. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a commercial vehicle four-wheel drive drive shaft and its selection and matching method and storage medium, that is, to select appropriate drive shaft specifications through a selection and matching method close to reality, thereby reducing the cost of the entire vehicle and improving the safety of the entire vehicle.

[0005] The present invention solves the above problems through the following technical solutions:

[0006] A method for selecting and matching a four-wheel drive transmission shaft for a commercial vehicle comprises the following steps:

[0007] Step A: Obtain basic parameters, including but not limited to vehicle mass (m), center of mass position, wheelbase (L), transmission, transfer case, and front and rear axle information;

[0008] Step B: Based on the obtained basic parameters and in combination with the chassis layout, the extreme axle load transfer is considered and the vehicle torque balance equation is established under different extreme working conditions with the center of mass as the zero point; then, based on the established vehicle torque balance equation under different extreme working conditions, the front axle dynamic axle load and the rear axle dynamic axle load under the extreme axle load transfer conditions of the corresponding extreme working conditions are obtained to obtain the maximum torque actually borne by each drive shaft under different extreme working conditions;

[0009] Step C: The maximum torque value of each transmission shaft under the obtained full throttle acceleration and reverse extreme axle load transfer conditions in four-wheel drive and two-wheel drive is compared with the maximum torque value of each transmission shaft under different extreme conditions, and the maximum value of the maximum torque value of each transmission shaft is selected as the actual minimum torque value for the selection of each transmission shaft, thereby realizing the selection of the transmission shaft.

[0010] As a further improvement of the present invention, the step B includes:

[0011] Step B100: Under the extreme axle load transfer four-wheel drive condition of full throttle acceleration, calculate the maximum torque T that the first, second, and third drive shafts actually bear. 1sq 、T 2sq 、T 3sq ;

[0012] Step B200: Under the extreme axle load transfer four-wheel drive condition of full throttle acceleration and reverse, calculate the maximum torque T that the first, second, and third drive shafts actually bear. 1sh 、T 2sh 、T 3sh ;

[0013] Step B300: Under the extreme axle load transfer two-wheel drive condition of full throttle acceleration, calculate the maximum torque T that the first and second drive shafts actually bear. 1lq 、T 2lq ;

[0014] Step B400: Under the extreme axle load transfer two-wheel drive condition of full throttle acceleration and reverse, calculate the maximum torque T that the first and second drive shafts actually bear. 1lh 、T 2lh .

[0015] As a further improvement of the present invention, in step C, the specific method is:

[0016] Section 1 Actual torque T for drive shaft selection 1real ≥max{T 1sq ,T 1sh ,T 1lq ,T 1lh Section 2 Actual torque T for drive shaft selection 2real ≥max{T 2sq ,T 2sh ,T 2lq ,T 2lh Section 3 Actual torque T for drive shaft selection 3real ≥max{T 3sq ,T 3sh}.

[0017] As a further improvement of the present invention, in step B100, the specific method is:

[0018] For the four-wheel drive condition of full throttle acceleration, considering the extreme axle load transfer, the vehicle torque balance equation under this extreme condition is established with the center of mass ⊙ as the zero point:

[0019]

[0020] Where, ⊙ is the center of mass of the vehicle when fully loaded; a is the distance from the center of mass to the front axle; b is the distance from the center of mass to the rear axle; h is the height of the center of mass from the ground; L is the wheelbase of the vehicle; R is the rolling radius of the tire; F q is the dynamic load on the front axle; F h is the dynamic load on the rear axle; μ is the ground friction coefficient; g is the acceleration of gravity; m is the vehicle mass;

[0021] According to formula 1, the dynamic load on the front axle under the extreme axle load transfer condition can be obtained when the four-wheel drive is accelerating at full throttle. Rear axle dynamic load

[0022] Then, when accelerating forward at full throttle in four-wheel drive mode,

[0023] The maximum torque actually borne by the first section of the transmission shaft is

[0024] The maximum torque actually borne by the second transmission shaft is

[0025]

[0026] The maximum torque actually borne by the third transmission shaft is

[0027]

[0028] Where T is the maximum torque of the engine; i Th is the maximum speed ratio of the first gear of the transmission; i a is the speed ratio of the front and rear axles; i f is the speed ratio of the transfer case; F is the ratio of the rear output torque of the transfer case to the front output torque.

[0029] As a further improvement of the present invention, in step B200, the specific method is:

[0030] For the four-wheel drive working condition of full throttle acceleration and reverse, considering the extreme axle load transfer, the vehicle torque balance formula under this extreme working condition is established with the center of mass ⊙ as the zero point:

[0031]

[0032] According to formula 2, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating backward at full throttle. Rear axle dynamic load

[0033] Then, when accelerating backward at full throttle,

[0034] The maximum torque on the first transmission shaft is

[0035] The maximum torque on the second transmission shaft is

[0036]

[0037] The maximum torque on the third transmission shaft is

[0038]

[0039] Among them, i TR It is the reverse speed ratio of the transmission.

[0040] As a further improvement of the present invention, in step B300, the specific method is:

[0041] For the two-wheel drive condition of full throttle acceleration, considering the extreme axle load transfer, the vehicle torque balance equation under this condition is established with the center of mass ⊙ as the zero point:

[0042]

[0043] According to formula 3, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating forward at full throttle. Rear axle dynamic load

[0044] Then, when accelerating forward at full throttle,

[0045] The maximum torque on the first transmission shaft is

[0046]

[0047] The maximum torque on the second transmission shaft is

[0048]

[0049] As a further improvement of the present invention, in step B400, the specific method is:

[0050] For the two-wheel drive condition of full throttle acceleration and reverse, considering the extreme axle load transfer, the vehicle torque balance equation under this condition is established with the center of mass ⊙ as the zero point:

[0051]

[0052] According to formula 4, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating backward at full throttle.

[0053] Rear axle dynamic load

[0054] Then, when accelerating backward at full throttle,

[0055] The maximum torque on the first transmission shaft is

[0056]

[0057] The maximum torque on the second transmission shaft is

[0058]

[0059] The present invention also solves the above problems through the following technical solutions:

[0060] A commercial vehicle four-wheel drive drive shaft comprises a first drive shaft, a second drive shaft and a third drive shaft, each of which has one end connected to a transmission, wherein the other end of the first drive shaft is connected to an input end of a transfer case, the other end of the second drive shaft is connected to a rear axle, and the other end of the third drive shaft is connected to a front axle; the commercial vehicle four-wheel drive drive shaft is selected using the commercial vehicle four-wheel drive drive shaft selection and matching method described above.

[0061] A storage medium, comprising:

[0062] at least one processor;

[0063] at least one memory for storing a program;

[0064] When the program is executed by a processor, the processor implements the above-mentioned method for selecting and matching a four-wheel drive shaft for a commercial vehicle.

[0065] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0066] (1) The present invention provides a method for selecting and matching a four-wheel drive transmission shaft for a commercial vehicle that meets the full-load limit working condition, i.e., full throttle acceleration and deceleration, for selecting and matching transmission shafts, thereby selecting appropriate transmission shaft specifications through theoretical calculations close to reality, reducing vehicle costs, and improving vehicle safety.

[0067] (2) The present invention comprehensively considers the accurate maximum torque that the transmission shaft can withstand under various extreme working conditions, considers the axle load transfer during acceleration and deceleration under the dynamic conditions of the entire vehicle, and calculates the axle load distribution values of the front and rear axles under the extreme axle load transfer conditions. According to the maximum torque value that the transmission shaft can withstand under different conditions, the selection of the transmission shaft is facilitated. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 A schematic flow chart of a method for selecting and matching a four-wheel drive shaft for a commercial vehicle according to the present invention;

[0069] Figure 2 This is a schematic diagram of the four-wheel drive force under full throttle acceleration forward working conditions of the present invention;

[0070] Figure 3 This is a schematic diagram of the four-wheel drive force under full throttle acceleration forward working conditions of the present invention;

[0071] Figure 4 This is a schematic diagram of the two-wheel drive force under full throttle acceleration forward working condition of the present invention;

[0072] Figure 5 This is a schematic diagram of the two-wheel drive force under full throttle acceleration and reverse working conditions of the present invention.

[0073] Figure numerals: 1, first section of transmission shaft; 2, second section of transmission shaft; 3, third section of transmission shaft. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below in conjunction with the drawings in the preferred embodiments of the present application. In the drawings, the same or similar reference numerals throughout represent the same or similar parts or parts with the same or similar functions. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain the present application, and should not be understood as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0075] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0076] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to a fixed connection, an indirect connection via an intermediate medium, internal communication between two components, or an interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0077] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are orientations or positional relationships based on the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0078] In addition, the terms "comprises" and "having" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or display that comprises a series of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, product, or display.

[0079] The following will be combined Figure 1-5 , a commercial vehicle four-wheel drive shaft and its selection and matching method and storage medium involved in the embodiments of this application are described in detail. It is worth noting that the following embodiments are only used to explain this application and do not constitute a limitation of this application.

[0080] Example:

[0081] Combined with attachment Figure 1-5 As shown, a method for selecting and matching a four-wheel drive shaft for a commercial vehicle includes the following steps:

[0082] A. Obtain basic parameters, including but not limited to vehicle mass (m), center of mass, wheelbase (L), transmission, transfer case, and front and rear axles;

[0083] B. Based on the obtained basic parameters and the chassis layout, the vehicle torque balance equations are established under different extreme operating conditions, taking the center of mass as the zero point and considering the extreme axle load transfer. The front and rear axle dynamic loads under the extreme axle load transfer conditions of the corresponding extreme operating conditions are then calculated based on the established vehicle torque balance equations under different extreme operating conditions to determine the maximum torque that each drive shaft can actually withstand under different extreme operating conditions.

[0084] B100: Under the extreme axle load transfer four-wheel drive condition of full throttle acceleration, calculate the maximum torque T that the first, second, and third drive shafts actually bear. 1sq 、T 2sq 、T 3sq ;

[0085] B200: Under the extreme axle load transfer four-wheel drive condition of full throttle acceleration and reverse, calculate the maximum torque T that the first, second, and third drive shafts actually bear. 1sh 、T 2sh 、T 3sh;

[0086] B300: Under the extreme axle load transfer two-wheel drive condition of full throttle acceleration, calculate the maximum torque T that the first and second drive shafts actually bear. 1lq 、T 2lq ;

[0087] B400: Under the extreme axle load transfer two-wheel drive condition of full throttle acceleration and reverse, calculate the maximum torque T that the first and second drive shafts actually bear. 1lh 、T 2lh ;

[0088] C. By comparing the maximum torque values of each transmission shaft under the extreme axle load transfer conditions of full throttle acceleration and reverse in four-wheel drive and two-wheel drive, the maximum value of the maximum torque values of each transmission shaft under different extreme conditions is selected as the actual minimum torque value for the selection of each transmission shaft, so as to achieve the selection of the transmission shaft.

[0089] In step C, the specific method is:

[0090] Section 1 Actual torque T for drive shaft selection 1real ≥max{T 1sq ,T 1sh ,T 1lq ,T 1lh Section 2 Actual torque T for drive shaft selection 2real ≥max{T 2sq ,T 2sh ,T 2lq ,T 2lh Section 3 Actual torque T for drive shaft selection 3real ≥max{T 3sq ,T 3sh}.

[0091] As a preferred solution: In step B100, the specific method is:

[0092] For the four-wheel drive condition of full throttle acceleration, such as Figure 1 As shown, considering the extreme axle load transfer, the vehicle moment balance equation is established with the center of mass ⊙ as the zero point:

[0093]

[0094] Where, ⊙ is the center of mass of the vehicle when fully loaded; a is the distance from the center of mass to the front axle; b is the distance from the center of mass to the rear axle; h is the height of the center of mass from the ground; L is the wheelbase of the vehicle; R is the rolling radius of the tire; F q is the dynamic load on the front axle; F h is the dynamic load on the rear axle; μ is the ground friction coefficient; g is the acceleration of gravity; m is the vehicle mass.

[0095] According to formula 1, the dynamic load on the front axle under the extreme axle load transfer condition can be obtained when the four-wheel drive is accelerating at full throttle. Rear axle dynamic load

[0096] Then, when accelerating forward at full throttle in four-wheel drive mode,

[0097] The maximum torque actually borne by the first section of the transmission shaft is

[0098] The maximum torque actually borne by the second transmission shaft is

[0099]

[0100] The maximum torque actually borne by the third transmission shaft is

[0101]

[0102] Where T is the maximum torque of the engine; i Th is the maximum speed ratio of the first gear of the transmission; i a is the speed ratio of the front and rear axles; i f is the speed ratio of the transfer case; F is the ratio of the rear output torque of the transfer case to the front output torque.

[0103] As a preferred solution: In step B200, the specific method is:

[0104] For full throttle acceleration and reverse four-wheel drive conditions, such as Figure 2 As shown, considering the extreme axle load transfer, the vehicle moment balance equation is established with the center of mass ⊙ as the zero point:

[0105]

[0106] Where O is the center of mass of the vehicle when fully loaded; a is the distance from the center of mass to the front axle; b is the distance from the center of mass to the rear axle; h is the height of the center of mass from the ground; L is the wheelbase of the vehicle; R is the rolling radius of the tire; F q is the dynamic load on the front axle; F h is the dynamic load on the rear axle; μ is the ground friction coefficient; g is the acceleration of gravity; m is the vehicle mass.

[0107] According to formula 2, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating backward at full throttle. Rear axle dynamic load

[0108] Then, when accelerating backward at full throttle,

[0109] The maximum torque on the first transmission shaft is

[0110] The maximum torque on the second transmission shaft is

[0111]

[0112] The maximum torque on the third transmission shaft is

[0113]

[0114] Where T is the maximum torque of the engine; i TR is the reverse gear ratio of the transmission; i a is the speed ratio of the front and rear axles; i f is the speed ratio of the transfer case; F is the ratio of the rear output torque of the transfer case to the front output torque.

[0115] As a preferred solution: In step B300, the specific method is:

[0116] For full throttle acceleration and forward two-wheel drive (rear-wheel drive) conditions, such as Figure 3 As shown, considering the extreme axle load transfer, the vehicle moment balance equation is established with the center of mass ⊙ as the zero point:

[0117]

[0118] Where, ⊙ is the center of mass of the vehicle when fully loaded; a is the distance from the center of mass to the front axle; b is the distance from the center of mass to the rear axle; h is the height of the center of mass from the ground; L is the wheelbase of the vehicle; R is the rolling radius of the tire; F q is the dynamic load on the front axle; F h is the dynamic load on the rear axle; μ is the ground friction coefficient; g is the acceleration of gravity; m is the vehicle mass.

[0119] According to formula 3, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating forward at full throttle. Rear axle dynamic load

[0120] Then, when accelerating forward at full throttle,

[0121] The maximum torque on the first transmission shaft is

[0122]

[0123] The maximum torque on the second transmission shaft is

[0124]

[0125] As a preferred solution: In step B400, the specific method is:

[0126] For full throttle acceleration and reverse two-wheel drive (rear-wheel drive) conditions, such as Figure 3As shown, considering the extreme axle load transfer, the vehicle moment balance equation is established with the center of mass ⊙ as the zero point:

[0127]

[0128] Where, ⊙ is the center of mass of the vehicle when fully loaded; a is the distance from the center of mass to the front axle; b is the distance from the center of mass to the rear axle; h is the height of the center of mass from the ground; L is the wheelbase of the vehicle; R is the rolling radius of the tire; F q is the dynamic load on the front axle; F h is the dynamic load on the rear axle; μ is the ground friction coefficient; g is the acceleration of gravity; m is the vehicle mass.

[0129] According to formula 4, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating backward at full throttle. Rear axle dynamic load

[0130] Then, when accelerating backward at full throttle,

[0131] The maximum torque on the first transmission shaft is

[0132]

[0133] The maximum torque on the second transmission shaft is

[0134]

[0135] Example 2:

[0136] A four-wheel drive drive shaft for a commercial vehicle comprises a first drive shaft 1, a second drive shaft 2, and a third drive shaft 3, each of which has one end connected to a transmission, wherein the other end of the first drive shaft is connected to an input end of a transfer case, the other end of the second drive shaft is connected to a rear axle, and the other end of the third drive shaft is connected to a front axle; the four-wheel drive drive shaft is selected using a commercial vehicle four-wheel drive drive shaft selection and matching method as described in Example 1.

[0137] Example 3:

[0138] A storage medium, comprising:

[0139] at least one processor;

[0140] at least one memory for storing a program;

[0141] When the program is executed by a processor, the processor implements a method for selecting and matching a four-wheel drive shaft for a commercial vehicle as described in Example 1.

[0142] The present invention comprehensively considers the accurate maximum torque that the transmission shaft can withstand under various extreme working conditions, and considers the axle load transfer during acceleration and deceleration under the dynamic conditions of the entire vehicle, and calculates the axle load distribution values of the front and rear axles under the extreme axle load transfer conditions. According to the maximum torque value that the transmission shaft can withstand under different conditions, the selection of the transmission shaft is facilitated.

[0143] Although the present invention is described herein with reference to illustrative embodiments of the present invention, the above embodiments are merely preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A method for selecting and matching a four-wheel drive shaft for a commercial vehicle, characterized in that: The following steps are involved: Step A: Obtain basic parameters, including but not limited to vehicle mass (m), center of mass position, wheelbase (L), transmission, transfer case, and front and rear axle information; Step B: Based on the obtained basic parameters and in combination with the chassis layout, the extreme axle load transfer is considered and the vehicle torque balance equation is established under different extreme working conditions with the center of mass as the zero point; then, based on the established vehicle torque balance equation under different extreme working conditions, the front axle dynamic axle load and the rear axle dynamic axle load under the extreme axle load transfer conditions of the corresponding extreme working conditions are obtained to obtain the maximum torque actually borne by each drive shaft under different extreme working conditions; Step C: The maximum torque value of each transmission shaft under the obtained full throttle acceleration and reverse extreme axle load transfer conditions in four-wheel drive and two-wheel drive is compared with the maximum torque value of each transmission shaft under different extreme conditions, and the maximum value of the maximum torque value of each transmission shaft is selected as the actual minimum torque value for the selection of each transmission shaft, thereby realizing the selection of the transmission shaft.

2. A method for selecting and matching a four-wheel drive transmission shaft for a commercial vehicle according to claim 1, characterized in that: The step B comprises: Step B100: Under the extreme axle load transfer four-wheel drive condition of full throttle acceleration, calculate the maximum torque T that the first, second, and third drive shafts actually bear. 1sq 、T 2sq 、T 3sq ; Step B200: Under the extreme axle load transfer four-wheel drive condition of full throttle acceleration and reverse, calculate the maximum torque T that the first, second, and third drive shafts actually bear. 1sh 、T 2sh 、T 3sh ; Step B300: Under the extreme axle load transfer two-wheel drive condition of full throttle acceleration, calculate the maximum torque T that the first and second drive shafts actually bear. 1lq 、T 2lq ; Step B400: Under the extreme axle load transfer two-wheel drive condition of full throttle acceleration and reverse, calculate the maximum torque T that the first and second drive shafts actually bear. 1lh 、T 2lh .

3. A method for selecting and matching a four-wheel drive transmission shaft for a commercial vehicle according to claim 2, characterized in that: In the step C, the specific method is: Section 1 Actual torque T for drive shaft selection 1real ≥max{T 1sq ,T 1sh ,T 1lq ,T 1lh Section 2 Actual torque T for drive shaft selection 2real ≥max{T 2sq ,T 2sh ,T 2lq ,T 2lh Section 3 Actual torque T for drive shaft selection 3real ≥max{T 3sq ,T 3sh }.

4. A method for selecting and matching a four-wheel drive transmission shaft for a commercial vehicle according to claim 2, characterized in that: In step B100, the specific method is: For the four-wheel drive condition of full throttle acceleration, considering the extreme axle load transfer, the vehicle torque balance equation under this extreme condition is established with the center of mass ⊙ as the zero point: Where, ⊙ is the center of mass of the vehicle when fully loaded; a is the distance from the center of mass to the front axle; b is the distance from the center of mass to the rear axle; h is the height of the center of mass from the ground; L is the wheelbase of the vehicle; R is the rolling radius of the tire; F q is the dynamic load on the front axle; F h is the dynamic load on the rear axle; μ is the ground friction coefficient; g is the acceleration of gravity; m is the vehicle mass; According to formula 1, the dynamic load on the front axle under the extreme axle load transfer condition can be obtained when the four-wheel drive is accelerating at full throttle. Rear axle dynamic load Then, when accelerating forward at full throttle in four-wheel drive mode, The maximum torque actually borne by the first section of the transmission shaft is The maximum torque actually borne by the second transmission shaft is The maximum torque actually borne by the third transmission shaft is Where T is the maximum torque of the engine; i Th is the maximum speed ratio of the first gear of the transmission; i a is the speed ratio of the front and rear axles; i f is the speed ratio of the transfer case; F is the ratio of the rear output torque of the transfer case to the front output torque.

5. The method for selecting and matching a four-wheel drive transmission shaft for a commercial vehicle according to claim 2, characterized in that: In step B200, the specific method is: For the four-wheel drive working condition of full throttle acceleration and reverse, considering the extreme axle load transfer, the vehicle torque balance formula under this extreme working condition is established with the center of mass ⊙ as the zero point: According to formula 2, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating backward at full throttle. Rear axle dynamic load Then, when accelerating backward at full throttle, The maximum torque on the first transmission shaft is The maximum torque on the second transmission shaft is The maximum torque on the third transmission shaft is Among them, i TR It is the reverse speed ratio of the transmission.

6. A method for selecting and matching a four-wheel drive transmission shaft for a commercial vehicle according to claim 2, characterized in that: In step B300, the specific method is: For the two-wheel drive condition of full throttle acceleration, considering the extreme axle load transfer, the vehicle torque balance equation under this condition is established with the center of mass ⊙ as the zero point: According to formula 3, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating forward at full throttle. Rear axle dynamic load Then, when accelerating forward at full throttle, The maximum torque on the first transmission shaft is The maximum torque on the second transmission shaft is 7. A method for selecting and matching a four-wheel drive transmission shaft for a commercial vehicle according to claim 2, characterized in that: In step B400, the specific method is: For the two-wheel drive condition of full throttle acceleration and reverse, considering the extreme axle load transfer, the vehicle torque balance equation under this condition is established with the center of mass ⊙ as the zero point: According to formula 4, the dynamic axle load of the front axle under the condition of extreme axle load transfer can be obtained when accelerating backward at full throttle. Rear axle dynamic load Then, when accelerating backward at full throttle, The maximum torque on the first transmission shaft is The maximum torque on the second transmission shaft is 8. A four-wheel drive transmission shaft for a commercial vehicle, characterized in that: The commercial vehicle four-wheel drive shaft comprises a first drive shaft, a second drive shaft and a third drive shaft, one end of each of which is connected to a transmission, wherein the other end of the first drive shaft is connected to an input end of a transfer case, the other end of the second drive shaft is connected to a rear axle, and the other end of the third drive shaft is connected to a front axle; the commercial vehicle four-wheel drive shaft is selected by a commercial vehicle four-wheel drive shaft selection and matching method as described in any one of claims 1 to 7.

9. A storage medium, characterized in that: include: at least one processor; at least one memory for storing a program; When the program is executed by a processor, the processor implements the method for selecting and matching a four-wheel drive shaft for a commercial vehicle as described in any one of claims 1 to 7.

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