A Constant Speed ​​Differential Transmission Ratio Combined Transmission Mechanism Based on Differential Gear Trains and Its Design Method

Abstract

This invention discloses a constant-speed differential transmission ratio combined transmission mechanism and its design method based on a differential gear train, belonging to the field of mechanical transmission technology. It includes a basic differential assembly composed of an inner central wheel, an outer central wheel, planetary gears, and a connecting rod, with the central shafts of the inner and outer central wheels serving as external input ends and the connecting rod as the output end. Pre-transmission components are connected in series with the central shafts of the inner and outer central wheels, and by limiting the transmission ratio and input of the two pre-transmission components, the basic transmission assembly achieves a constant-speed differential transmission ratio, thereby realizing constant-speed differential transmission. The combined transmission mechanism of this invention has a simple structure and is easy to set up, enabling conventional differential gear trains to achieve constant-speed differential transmission. This allows differential gear trains to be used in fields and scenarios requiring precise speed ratio transmission, achieving stable speed synthesis and output control without the introduction of complex electronic control systems, improving transmission accuracy and reliability, and possessing good practical value and application prospects.

Description

Technical Field

[0001] This invention belongs to the field of mechanical transmission technology, specifically relating to a constant speed differential transmission ratio combined transmission mechanism based on differential gear trains and its design method. Background Technology

[0002] In mechanical transmission, the most common form of transmitting motion and power between any two shafts is gear transmission. In engineering, a series of meshing gear transmission devices are often used, also known as gear train transmission.

[0003] Based on whether the geometric axes of each gear are fixed during operation, gear trains are generally classified into two basic forms: fixed-axis gear trains and planetary gear trains. However, in more complex transmissions, multiple basic gear trains are often appropriately combined into hybrid gear trains. Planetary gear trains are widely used in engineering due to their advantages such as compact structure, small size, high transmission efficiency, wide transmission ratio range, high transmission power, and strong load-bearing capacity. For planetary gear trains, when they have one degree of freedom, they are generally called planetary gear trains; when they have two degrees of freedom, they are generally called differential gear trains. Differential gear trains can achieve the synthesis and decomposition of motion and are widely used in automotive differentials, helicopter rotor systems, etc.

[0004] However, for a classic differential gear train with two center wheels as inputs and a connecting rod as the output (such as...), Figure 2 As shown in the diagram, its transmission ratio is not a constant value, but a bivariate function that varies with the speeds of the two input gear trains. This non-constant ratio characteristic makes it difficult to achieve accurate output control, limiting its application in precision transmission applications requiring precise and stable gear ratios (such as machine tools, aircraft engine accessory drives, and special vehicle speed control systems). Although an additional control system can be set up in engineering to stabilize the output, this undoubtedly increases the control cost and complexity of the system, affecting the application of differential gear train transmission mechanisms. Summary of the Invention

[0005] In view of one or more of the above-mentioned defects or improvement needs of the prior art, the present invention provides a constant speed differential transmission ratio combined transmission mechanism based on differential gear train and its design method, which can realize constant speed differential transmission of differential gear train and reduce the control cost and complexity of differential gear train transmission system.

[0006] To achieve the above objectives, one aspect of the present invention provides a constant speed differential transmission ratio combined transmission mechanism based on a differential gear train, comprising a basic differential assembly composed of an inner central wheel, an outer central wheel, planetary gears, and a connecting rod; wherein the central axes of the inner central wheel and the outer central wheel are respectively the input ends of the mechanism, and the connecting rod disposed between the inner central wheel and the planetary gears is the output end of the mechanism; further comprising:

[0007] A first front-drive assembly connected in series with the central shaft of the inner central wheel;

[0008] A second front-drive assembly is connected in series with the central shaft of the outer center wheel;

[0009] Furthermore, the two front drive units are configured to satisfy the following conditions:

[0010]

[0011]

[0012]

[0013]

[0014] in, The input speed of the first front-drive assembly; The input speed of the second front drive assembly; The transmission ratio of the first front-mounted transmission assembly is a constant. ; The transmission ratio of the second front drive assembly; The gear ratio of the basic differential component, and , The number of teeth on the inner center gear. The number of teeth on the outer center gear; The speed difference transmission ratio of the combined transmission mechanism; The input speed difference between the two front drive components; This refers to the output speed of the connecting rod.

[0015] As a further improvement of the present invention, the two front-mounted transmission components also satisfy the following conditions:

[0016] ;and

[0017] The transmission ratio between the input end of the first front transmission component and the output end of the linkage The transmission ratio between the input end of the second front drive assembly and the output end of the tie rod. Equal in size, opposite in direction, and equal to the speed difference transmission ratio Half of it.

[0018] As a further improvement of the present invention, the two front-mounted transmission components also satisfy the following conditions:

[0019] ;and

[0020] Rotation speed of the inner center wheel Rotation speed of the outer center wheel The rotational speed of the tie rod They are all equal.

[0021] As a further improvement of the present invention, both front transmission components are gear transmission mechanisms with a fixed transmission ratio.

[0022] As a further improvement of the present invention, at least one of the front transmission components is either a fixed-axis gearbox or a planetary reducer.

[0023] Another aspect of the present invention provides a design method for a constant speed difference transmission ratio combined transmission mechanism based on a differential gear train, used to construct the aforementioned constant speed difference transmission ratio combined transmission mechanism based on a differential gear train, comprising the following steps:

[0024] S1: Determine the gear ratio of the basic differential assembly. ;

[0025] S2: Determine the speed difference transmission ratio of the combined transmission mechanism. ;

[0026] S3: Calculate the transmission ratio of the two front drive components according to the following formula. , and input speed difference :

[0027] ;

[0028]

[0029]

[0030] S4: Based on the transmission ratio and Select the type and specifications of the two front-mounted transmission components, connect the first front-mounted transmission component in series on the central shaft of the inner central wheel of the basic differential component, and connect the second front-mounted transmission component in series on the central shaft of the outer central wheel of the basic differential component to obtain a constant speed differential transmission ratio combined transmission mechanism.

[0031] As a further improvement of the present invention, an output verification method for a constant speed difference transmission ratio combined transmission mechanism is also included, which includes the following process:

[0032] Select any two different sets of external input speeds as the input speeds of the two front drive components, and the input speed difference between the two sets of external input speeds is 1 / 2. ;

[0033] Calculate the output speed under the two sets of external input speeds using the following formulas:

[0034] ;

[0035] Determine whether the output speeds obtained under two sets of external input speeds are the same.

[0036] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0037] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include:

[0038] The present invention discloses a constant speed differential transmission ratio combined transmission mechanism based on a differential gear train, which includes a basic differential component composed of an inner center wheel, an outer center wheel, planetary gears, and a connecting rod. The central shafts of the inner and outer center wheels serve as external input ends, and the connecting rod serves as the output end. A front transmission component is connected in series with the central shafts of the inner and outer center wheels respectively. By limiting the transmission ratio and input of the two front transmission components, the basic transmission component has a constant speed differential transmission ratio, thereby realizing constant speed differential transmission. This simplifies the output control process of the differential gear train and improves the output control accuracy of the combined transmission mechanism.

[0039] The constant speed differential transmission ratio combined transmission mechanism based on differential gear trains in this invention has a simple structure and is easy to set up. By setting front transmission components for the inner and outer center wheels and designing the transmission ratio and input speed difference of the front transmission components, a conventional differential gear train can achieve constant speed differential transmission. This allows the differential gear train to be used in fields and scenarios requiring precise speed ratio transmission. Stable speed synthesis and output control can be achieved without the introduction of a complex electronic control system, improving transmission accuracy and reliability. It has good practical value and application prospects. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the constant speed differential transmission ratio combined transmission mechanism based on differential gear train in an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of a traditional differential gear train. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0044] In the description of this invention, it should be understood that, unless otherwise expressly specified and limited, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0045] Furthermore, unless otherwise expressly defined, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0048] Below, for reference Figure 1 This invention describes a constant speed differential transmission ratio combined transmission mechanism based on a differential gear train and its design method, according to a preferred embodiment of the present invention.

[0049] like Figure 1 As shown, the combined transmission mechanism in the preferred embodiment of the present invention is designed based on a basic differential component, wherein the basic differential component is as follows: Figure 2 As shown, it includes an inner center wheel, an outer center wheel, planetary wheels, and a connecting rod H.

[0050] Specifically, the inner central gear and the planetary gears are gears with teeth on their outer circumferences, while the outer central gear is a gear ring with teeth on its inner circumference. The inner diameter of the outer central gear is equal to the sum of the outer diameters of the inner central gear and the planetary gears, so that the central axis of the inner central gear and the central axis of the outer central gear are coaxially arranged, and the planetary gears are meshed between the outer central gear and the inner central gear. Correspondingly, a connecting rod H is arranged between the inner central gear and the planetary gears, and the two ends of the connecting rod H are rotatably assembled to the central axis of the inner central gear and the central axis of the planetary gear, respectively.

[0051] Meanwhile, in the preferred embodiment, the central axes of the inner and outer central wheels of the basic differential assembly are respectively the input ends of the basic differential assembly, and the connecting rod H (the end assembled with the inner central wheel) is the output end of the basic differential assembly.

[0052] As for the basic differential component in the preferred embodiment, it belongs to a two-degree-of-freedom planetary gear system that is relatively common in the prior art. Its assembly and setting can be quickly realized based on existing mature technologies, so it will not be described in detail here.

[0053] As a core improvement in the preferred embodiment of the present invention, based on the aforementioned basic differential assembly, a front transmission assembly is further provided for the inner center wheel and the outer center wheel, which serve as input ends, namely:

[0054] A first front-drive assembly connected in series with the central shaft of the inner central wheel;

[0055] A second front-drive assembly is connected in series with the central shaft of the outer center wheel;

[0056] At the same time, the two front drive assemblies are configured to meet the following conditions:

[0057]

[0058]

[0059]

[0060] in, The input speed of the first front-drive assembly; The input speed of the second front drive assembly; The transmission ratio of the first front-mounted transmission assembly is a constant. ; The transmission ratio of the second front drive assembly; The gear ratio of the basic differential component, and , The number of teeth on the inner center gear. The number of teeth on the outer center gear; This refers to the speed difference transmission ratio of the combined transmission mechanism.

[0061] By configuring the two front-mounted transmission components as described above, the non-constant speed difference transmission ratio of a traditional differential gear train (basic differential component) can be converted into a constant value. This enables constant speed differential transmission in traditional differential gear trains. Thus, for the aforementioned differential gear trains involving two input ends, the output speed can be accurately controlled by adjusting the speed difference between the two input ends. Stable speed synthesis and output control can be achieved without the need for a complex electronic control system, thereby improving transmission accuracy and reliability.

[0062] Furthermore, the determination process for the aforementioned two front-mounted transmission components in the preferred embodiment is preferably as follows:

[0063] First, the basic differential assembly includes the inner center wheel (number of teeth). Planetary gears (number of teeth) ), outer center gear (number of teeth) ) and tie rod H. Among them, Meanwhile, define the tooth ratio of this component. Obviously, .

[0064] According to the formula for calculating the transmission ratio of a fixed-axis gear train, the speed relationship between the connecting rod H and the inner and outer central wheels satisfies:

[0065] (1)

[0066] In the formula, The output speed of the linkage H; The input speed of the inner center wheel; The input speed of the outer center wheel; The gear ratio of the basic differential component.

[0067] Meanwhile, based on the rotational speed relationship in equation (1), the transmission ratios from the inner and outer center wheels to the tie rod H in the basic differential assembly can be obtained:

[0068] (2)

[0069] In the formula, The transmission ratio from the inner center wheel to the connecting rod H; The transmission ratio from the inner center wheel to the connecting rod H is given.

[0070] According to equation (2), it can be seen that for differential gear train transmission, although the gear ratio It is a constant value, but , Both refer to the rotational speeds of the two prime movers (input terminals). , A bivariate function. Thus, if , If there is no fixed matching relationship between them, the transmission ratio will exhibit non-constant characteristics, resulting in varying output speeds. It is difficult to control accurately.

[0071] Thus, in a preferred embodiment, a front transmission assembly is provided for each of the two input ends, namely, a first front transmission assembly (transmission ratio) is provided on the inner center wheel input shaft. ) and a second front transmission assembly (transmission ratio) mounted on the outer center wheel input shaft. ).

[0072] More specifically, the gear ratio of the first front drive assembly is defined. For a constant value Based on the gear ratio of the basic differential assembly, the transmission ratio of the second front transmission assembly is adjusted. Set as ,Right now .

[0073] Given a fixed gear ratio for the basic differential assembly, and with the transmission ratios of the two front transmission assemblies fixed, the input speeds of the two front transmission assemblies and the input speeds of the inner and outer center wheels satisfy the following relationship:

[0074] (3)

[0075] In the formula, The input speed is the speed at the input end of the first front-mounted transmission component; This is the input speed at the input end of the second front drive assembly.

[0076] Combining equations (1) and (3), the output speed of the tie rod H can be expressed as:

[0077] (4)

[0078] In the formula, For the input speed difference, and .

[0079] Based on the above design, the speed difference transmission ratio of the entire combined transmission mechanism can be further defined. for:

[0080] (5)

[0081] According to equation (5), the speed difference transmission ratio of this combined transmission mechanism can be seen. By setting a constant value, the design goal of constant speed differential transmission ratio for the combined transmission mechanism based on differential gear trains is achieved.

[0082] Meanwhile, since this constant speed difference transmission ratio combined transmission mechanism still has two degrees of freedom, its two front transmission component input ends to the tie rod H output still have their own transmission ratios, which are:

[0083] (6)

[0084] According to equation (6), it can be seen that although , Still accompanied , The transmission ratios change accordingly, but by combining the aforementioned formulas (2), (3), (5), and (6), the following relationships can be observed between the relevant transmission ratios:

[0085] (7)

[0086] Meanwhile, based on the working principle and characteristics of differential gear trains, and combined with the above calculation relationships, it can be seen that the combined transmission mechanism has the following special cases:

[0087] (a) when ,Right now At this time, there is no speed difference at the input of the combined transmission mechanism. That is, the linkage does not move, and there is no speed output. Correspondingly, , , , None of these have mathematical meaning; therefore, for a combined transmission mechanism, the prerequisite for its normal output speed is that it must meet the following conditions. .

[0088] (b) When ,Right now When, its speed difference transmission ratio It is a fixed value, that is ;at this time, , Although it is not a constant value, the difference between the two is a fixed value and equal to the speed difference transmission ratio of the combined transmission mechanism. .

[0089] (c) When At that time, , Opposite in direction, equal in magnitude, and equal to the speed difference transmission ratio of the mechanism. Half of it.

[0090] (d) When ,Right now At that time, ,Right now At this point, the basic differential assembly is not performing differential operation; the components of the basic differential assembly do not move relative to each other but rotate synchronously as a whole. Correspondingly, the speed difference transmission ratio of the combined transmission mechanism remains [value missing]. The output speed of the linkage H is or .

[0091] Based on the aforementioned constant speed difference transmission ratio combined transmission mechanism, constant speed difference transmission of traditional differential gear trains can be realized, so that the output speed of the connecting rod can establish a strict linear relationship with the input speed difference of the two front transmission components. Then, by controlling only the input speed difference of the two input ends, the output control of the combined transmission mechanism can be accurately completed. Thus, the differential gear train can be used in fields that require precise speed ratio transmission. Stable speed synthesis and output control can be achieved without the introduction of a complex electronic control system, improving transmission accuracy and reliability.

[0092] It is understood that when selecting the front transmission component in the preferred embodiment, any transmission component in the prior art can be selected as needed, as long as it can meet the requirements of series assembly with the inner and outer center wheels in the basic differential component.

[0093] As an example, both front drive components are preferably gear transmission mechanisms with a fixed transmission ratio.

[0094] More specifically, at least one of the front drive components is either a fixed-axis gearbox or a planetary reducer.

[0095] Furthermore, as another aspect of the present invention, a method for setting up the aforementioned constant speed differential transmission ratio combined transmission mechanism based on a basic differential component (conventional differential gear train) is also provided, which preferably includes the following process:

[0096] S1: Determine the gear ratio of the basic differential assembly. ;

[0097] Specifically, the gear ratio of the basic differential component By obtaining the number of teeth on the inner center gear of the basic differential component Number of teeth on the outer center gear and in combination with formula Calculated.

[0098] S2: Determine the speed difference transmission ratio of the combined transmission mechanism. ;

[0099] In actual design, the speed difference transmission ratio can be set according to the transmission needs of the mechanism. It is usually given in advance during the mechanism design, such as 10, 20, 30, etc.

[0100] S3: Calculate the transmission ratio of the two front drive components according to the following formula. , and input speed difference :

[0101] ;

[0102]

[0103]

[0104] S4: Based on the transmission ratio and Select the type and specifications of the two front-mounted transmission components, connect the first front-mounted transmission component in series on the central shaft of the inner central wheel of the basic differential component, and connect the second front-mounted transmission component in series on the central shaft of the outer central wheel of the basic differential component to obtain a constant speed differential transmission ratio combined transmission mechanism.

[0105] More specifically, based on the aforementioned design method, a method for verifying the output of a constant speed difference transmission ratio combined transmission mechanism is further proposed, which includes the following process:

[0106] Select any two different sets of external input speeds as the input speeds of the two front drive components, and the input speed difference between the two sets of external input speeds is calculated. ;

[0107] Calculate the output speed under the two sets of external input speeds using the following formulas:

[0108] ;

[0109] Determine whether the output speeds obtained under two sets of external input speeds are the same.

[0110] The design method described above will be illustrated below through a specific embodiment.

[0111] In this embodiment, a precision speed control system requires the achievement of a speed difference transmission ratio. The combined transmission mechanism. Meanwhile, the differential gear train in this precision speed control system includes a number of teeth. The inner center gear has 20 teeth and the number of teeth is 20. The outer center wheel is 60.

[0112] Specifically, the design process of this combined transmission mechanism is as follows:

[0113] S1: Determine the gear ratio of the basic differential assembly. ;in, .

[0114] S2: Determine the speed difference transmission ratio of the combined transmission mechanism. ;Right now, .

[0115] S3: Calculate the transmission ratio of the two front drive components. , and input speed difference :

[0116] ;

[0117] ;

[0118] .

[0119] S4: Based on the transmission ratio and Select the type and specifications of the two front drive components, where the negative sign indicates that the input and output directions are opposite.

[0120] In this embodiment, a fixed-axis gearbox with a transmission ratio of 5 (i.e., the first front transmission assembly) is connected in series on the central shaft of the inner central wheel, and a fixed-axis gearbox with a transmission ratio of -15 (i.e., the second front transmission assembly) is connected in series on the central shaft of the outer central wheel, thereby obtaining a constant speed difference transmission ratio combined transmission mechanism.

[0121] For the aforementioned combined transmission mechanism, the following verification process is performed:

[0122] Assuming the output speed of the mechanism is 30, that is, the input speed difference... ;

[0123] At this point, the two selected sets of external input speeds are respectively , ; , .

[0124] Calculate the output speed under two sets of external input speeds, respectively:

[0125]

[0126]

[0127] Obviously, when the input speed difference between the two sets of external inputs is constant, the output speed of the combined transmission mechanism remains unchanged by setting the two front transmission components, indicating that the combined transmission mechanism has a constant speed difference transmission ratio at this time.

[0128] Similarly, when the output speed of the combined transmission mechanism changes, the input speed difference between the two external inputs can be adjusted accordingly. Taking the aforementioned embodiment as an example, when the output speed changes from 30 to 20, the input speed difference only needs to be adjusted to... This can satisfy the output requirements of the combined transmission mechanism.

[0129] The constant speed differential transmission ratio combined transmission mechanism based on differential gear trains in this invention has a simple structure and is easy to set up. By setting front transmission components for the inner and outer center wheels and designing the transmission ratio and input speed difference of the front transmission components, a conventional differential gear train can achieve constant speed differential transmission. This allows the differential gear train to be used in fields and scenarios requiring precise speed ratio transmission. Stable speed synthesis and output control can be achieved without the introduction of a complex electronic control system, improving transmission accuracy and reliability. It has good practical value and application prospects.

[0130] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A constant speed differential transmission ratio combined transmission mechanism based on a differential gear train, comprising a basic differential assembly composed of an inner center gear, an outer center gear, planetary gears, and a connecting rod; wherein, The central axes of the inner and outer central wheels are respectively the input ends of the mechanism, and the connecting rod between the inner central wheel and the planetary gears is the output end of the mechanism; characterized in that, Also includes: A first front-drive assembly connected in series with the central shaft of the inner central wheel; A second front-drive assembly is connected in series with the central shaft of the outer center wheel; Furthermore, the two front drive units are configured to satisfy the following conditions: in, The input speed of the first front-drive assembly; The input speed of the second front drive assembly; The transmission ratio of the first front-mounted transmission assembly is a constant. ; The transmission ratio of the second front drive assembly; The gear ratio of the basic differential component, and , The number of teeth on the inner center gear. The number of teeth on the outer center gear; The speed difference transmission ratio of the combined transmission mechanism; The input speed difference between the two front drive components; This refers to the output speed of the connecting rod.

2. The constant speed differential transmission ratio combined transmission mechanism based on differential gear train according to claim 1, characterized in that, The two front drivetrain components also meet the following conditions: ;and The transmission ratio between the input end of the first front transmission component and the output end of the linkage The transmission ratio between the input end of the second front drive assembly and the output end of the tie rod. Equal in size, opposite in direction, and equal to the speed difference transmission ratio Half of it.

3. The constant speed differential transmission ratio combined transmission mechanism based on differential gear train according to claim 1, characterized in that, The two front drivetrain components also meet the following conditions: ;and Rotation speed of the inner center wheel Rotation speed of the outer center wheel The rotational speed of the tie rod They are all equal.

4. The constant speed differential transmission ratio combined transmission mechanism based on a differential gear train according to any one of claims 1 to 3, characterized in that, Both front-mounted transmission components are gear transmission mechanisms with a fixed transmission ratio.

5. The constant speed differential transmission ratio combined transmission mechanism based on differential gear train according to claim 4, characterized in that, At least one of the front transmission components is either a fixed-axis gearbox or a planetary reducer.

6. A design method for a constant speed difference transmission ratio combined transmission mechanism based on a differential gear train, used to construct a constant speed difference transmission ratio combined transmission mechanism based on a differential gear train as described in any one of claims 1 to 5, characterized in that, The process includes the following: S1: Determine the gear ratio of the basic differential assembly. ; S2: Determine the speed difference transmission ratio of the combined transmission mechanism. ; S3: Calculate the transmission ratio of the two front drive components according to the following formula. , and input speed difference : ； S4: Based on the transmission ratio and Select the type and specifications of the two front-mounted transmission components, connect the first front-mounted transmission component in series on the central shaft of the inner central wheel of the basic differential component, and connect the second front-mounted transmission component in series on the central shaft of the outer central wheel of the basic differential component to obtain a constant speed differential transmission ratio combined transmission mechanism.

7. The design method of the constant speed difference transmission ratio combined transmission mechanism based on differential gear train according to claim 6, characterized in that, It also includes an output verification method for a constant speed difference transmission ratio combined transmission mechanism, which includes the following process: Select any two different sets of external input speeds as the input speeds of the two front drive components, and the input speed difference between the two sets of external input speeds is 1 / 2. ; Calculate the output speed under the two sets of external input speeds using the following formulas: ； Determine whether the output speeds obtained under two sets of external input speeds are the same.

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