Speed reducer shell bolt hole design method, electric drive axle speed reducer and vehicle

Abstract

The invention relates to a speed reducer shell bolt hole design method, an electric drive axle speed reducer and a vehicle, and relates to the technical field of speed reducer manufacturing, and the method comprises the steps that a model of a single-circle thread layer in a thread section is established according to parameters of a bolt, and the single-circle thread layer is unfolded along the root to form a thread tooth section; carrying out stress analysis on the thread section to obtain the safe shear strength of the root section of the thread section and the safe bending strength of the root section of the thread section; and obtaining the effective thread depth of the thread section according to the tightening torque of the bolt, the safe shear strength of the root section of the thread section and the safe bending strength of the root section of the thread section. The problems that an electric drive axle speed reducer shell of an iron casting structure is large in weight and difficult to meet the lightweight requirement of an automobile, the speed reducer shell made of a lightweight material is different from the electric drive axle speed reducer shell of the iron casting structure in effective thread depth, the test speed of an exhaustion method is low, the test efficiency is reduced, and the test cost is low are solved. And the manufacturing efficiency is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of reducer manufacturing, and in particular to a reducer housing bolt hole design method, an electric drive axle reducer and a vehicle. Background Art

[0002] The electric drive axle is a key component for new energy vehicles to occupy a place in the market, and it plays a positive role in achieving the "dual carbon" goal. Compared with traditional axles, the electric drive axle adopts a main reduction structure with motor drive and multi-stage reduction gears. The structure of the electric drive axle and the high speed of the motor make the excellent lubrication of the bearing an important determinant of the reliability and service life of the electric drive axle.

[0003] In the prior art, the reducer housing of the electric drive axle is generally a cast iron structure, and the reducer housing and the bearing cover are connected by bolts. The effective thread depth on the reducer housing needs to be greater than or equal to 1.5 times the major diameter of the thread.

[0004] However, the electric drive axle reducer housing with a cast iron structure is heavy and difficult to meet the requirements of lightweight automobiles. The electric drive axle reducer housing made of lightweight materials has an effective thread depth different from that of the electric drive axle reducer housing with a cast iron structure. The exhaustive testing speed is slow, which reduces the test efficiency and thus reduces the manufacturing efficiency. Summary of the invention

[0005] The present application provides a method for designing bolt holes of a reducer housing, an electric drive axle reducer and a vehicle, which can solve the problem that the electric drive axle reducer housing with a cast iron structure in the prior art is heavy and difficult to meet the requirements of lightweight automobiles. The electric drive axle reducer housing is manufactured with lightweight materials, and the effective thread depth is different from that of the electric drive axle reducer housing with a cast iron structure. The exhaustive method is used for testing, which is slow, and there is a problem of reducing test efficiency and thus reducing manufacturing efficiency.

[0006] In a first aspect, an embodiment of the present application provides a method for designing a bolt hole of a reducer housing, which comprises the following steps:

[0007] A model of a single-turn thread layer in a thread segment is established according to the parameters of the bolt, and the single-turn thread layer is expanded along the root to form a thread segment;

[0008] Perform stress analysis on the thread segment to obtain the safe shear strength of the root section of the thread segment and the safe bending strength of the root section of the thread segment;

[0009] The effective thread depth of the thread segment is obtained based on the tightening torque of the bolt, the safe shear strength of the root section of the thread segment, and the safe bending strength of the root section of the thread segment.

[0010] In one embodiment, the stress analysis of the thread segment to obtain the safe shear strength of the root section of the thread segment and the safe bending strength of the root section of the thread segment includes:

[0011] Adjust the average pressure applied to the circumference of the thread segment mid-diameter to obtain the shear strength curve of the thread segment root section and the bending strength curve of the thread segment root section;

[0012] According to the shear strength curve of the cross section at the root of the thread tooth segment and the bending strength curve of the cross section at the root of the thread tooth segment, the safe shear strength of the cross section at the root of the thread tooth segment and the safe bending strength of the cross section at the root of the thread tooth segment are obtained.

[0013] In one embodiment, according to the formula: b=0.65P to obtain the safe shear strength of the root section of the thread segment;

[0014] Among them, t is the safe shear strength of the root section of the thread segment, Q is the total pressure borne by the thread segment, u is the number of thread layers, πD is the root length of the thread segment, b is the root thickness of the thread segment, [t] is the allowable shear stress of the thread segment material, P is the thread pitch, and D is the major diameter of the thread segment.

[0015] In one embodiment, according to the formula: b=0.65P to obtain the safe bending strength of the root section of the thread segment;

[0016] Among them, σ b is the safety bending strength of the cross section at the root of the thread segment, Q is the total pressure borne by the thread segment, u is the number of thread layers, πD is the length of the root of the thread segment, b is the thickness of the root of the thread segment, [σ] b is the allowable bending stress of the thread segment material, l is the bending force arm, P is the thread pitch, D is the major diameter of the thread segment, and D2 is the median diameter of the thread segment.

[0017] In one embodiment, the method of obtaining the effective thread depth of the thread segment according to the tightening torque of the bolt, the safe shear strength of the root section of the thread segment, and the safe bending strength of the root section of the thread segment includes:

[0018] According to the safe shear strength of the cross section at the root of the thread tooth segment and the safe bending strength of the cross section at the root of the thread tooth segment, the safe shear strength and safe bending strength of the cross section at the root of the single-turn thread layer are obtained;

[0019] According to the tightening torque of the bolt, the safe shear strength and safe bending strength of the root section of a single-turn thread layer, the number of thread layers required to withstand the tightening torque of the bolt is obtained;

[0020] Get the effective thread depth of the thread segment based on the number of thread layers.

[0021] In one embodiment, after obtaining the effective thread depth of the thread segment, the method further includes obtaining the actual depth of the bolt hole according to the parameters of the bolt and the effective thread depth of the thread segment.

[0022] In a second aspect, the embodiment of the present application further provides an electric drive axle reducer, which includes:

[0023] The reducer housing has mounting holes at both ends of its upper side, and the set effective thread depth of the threaded section in the mounting hole is designed according to the above-mentioned reducer housing bolt hole design method;

[0024] A bearing cover is arranged on the upper side of the reducer housing. The bearing cover is provided with a connecting hole corresponding to the mounting hole. The connecting hole and the threaded section are both used to cooperate with the bolt thread. The bolt passes through the connecting hole and extends into the mounting hole to be connected with the threaded section. The bolt is used to connect the bearing cover and the reducer housing.

[0025] In one embodiment, a steel sleeve is provided in the mounting hole, the steel sleeve is cast integrally with the reducer housing, and the threaded section is provided on the inner side of the steel sleeve.

[0026] In one embodiment, the reducer housing is made of aluminum alloy.

[0027] In a third aspect, an embodiment of the present application further provides a vehicle, which includes the above-mentioned electric drive axle reducer.

[0028] The beneficial effects brought by the technical solution provided by the embodiments of the present application include:

[0029] When manufacturing the electric drive axle reducer, mounting holes are provided at both ends of the upper side of the reducer housing. The set effective thread depth of the threaded section in the mounting hole is designed according to the design method of the bolt hole of the reducer housing. The bearing cover is arranged on the upper side of the reducer housing. The bearing cover is provided with a connecting hole corresponding to the mounting hole. The connecting hole and the threaded section are both used to cooperate with the bolt thread. The bolt passes through the connecting hole and extends into the mounting hole to be connected with the threaded section. The bolt is used to connect the bearing cover and the reducer housing. When designing the effective thread depth, firstly, a model of a single-turn thread layer in the thread segment is established according to the parameters of the bolt, and the single-turn thread layer is expanded along the root to form a thread segment, and the force analysis of the thread segment is performed to obtain the safe shear strength of the root section of the thread segment and the safe bending strength of the root section of the thread segment. According to the tightening torque of the bolt, the safe shear strength of the root section of the thread segment and the safe bending strength of the root section of the thread segment, the effective thread depth of the thread segment is obtained. The acquisition speed is fast, which improves the design speed of the thread segment in the mounting hole, thereby improving the manufacturing efficiency of the reducer housing, and solves the problem that the electric drive axle reducer housing with a cast iron structure in the prior art is heavy and difficult to meet the requirements of lightweight automobiles. The electric drive axle reducer housing is manufactured with lightweight materials, and the effective thread depth is different from that of the electric drive axle reducer housing with a cast iron structure. The exhaustive test speed is slow, which reduces the test efficiency and thus reduces the manufacturing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 It is a schematic structural diagram of an electric drive axle reducer embodiment of the present invention.

[0032] Figure 2 It is a schematic structural diagram of an electric drive axle reducer embodiment of the present invention.

[0033] Figure 3 It is a structural schematic diagram of the thread segment in an embodiment of a method for designing a bolt hole for a reducer housing of the present invention.

[0034] Figure 4 This is the tensile test result data table.

[0035] Figure 5 This is a graph of tensile test results.

[0036] In the figure: 1. reducer housing; 11. mounting hole; 2. bearing cover; 21. connecting hole; 3. bolt; 4. steel sleeve; 5. threaded segment. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0038] The embodiments of the present application provide a method for designing bolt holes of a reducer housing, an electric drive axle reducer and a vehicle, which can solve the problem that the electric drive axle reducer housing with a cast iron structure in the prior art is heavy and difficult to meet the requirements of lightweight automobiles. The electric drive axle reducer housing is manufactured with lightweight materials, and the effective thread depth is different from that of the electric drive axle reducer housing with a cast iron structure. The exhaustive method is used for testing, which is slow, and there is a problem of reducing test efficiency and thus reducing manufacturing efficiency.

[0039] like Figure 1 , Figure 2 and Figure 3 As shown, on the one hand, the present application provides a method for designing a bolt hole of a reducer housing, which comprises the following steps:

[0040] A model of a single-turn thread layer in the thread segment is established according to the parameters of the bolt 3 , and the single-turn thread layer is expanded along the root to form a thread segment 5 .

[0041] A stress analysis is performed on the thread segment 5 to obtain the safe shear strength of the root section of the thread segment 5 and the safe bending strength of the root section of the thread segment 5.

[0042] The effective thread depth of the thread segment is obtained according to the tightening torque of the bolt 3, the safe shear strength of the root section of the thread segment 5, and the safe bending strength of the root section of the thread segment 5.

[0043] When manufacturing the electric drive axle reducer, mounting holes 11 are provided at both ends of the upper side of the reducer housing 1. The set effective thread depth of the threaded section in the mounting hole 11 is designed according to the design method of the bolt hole of the reducer housing. The bearing cover 2 is arranged on the upper side of the reducer housing 1. The bearing cover 2 is provided with a connecting hole 21 corresponding to the mounting hole 11. The connecting hole 21 and the threaded section are both used for threaded cooperation with the bolt 3. The bolt 3 passes through the connecting hole 21 and extends into the mounting hole 11 to be connected with the threaded section. The bolt 3 is used to connect the bearing cover 2 and the reducer housing 1. When designing the effective thread depth, firstly, a model of a single-turn thread layer in the thread segment is established according to the parameters of the bolt 3, and the single-turn thread layer is expanded along the root to form a thread segment 5, and a force analysis is performed on the thread segment 5 to obtain the safe shear strength of the root section of the thread segment 5 and the safe bending strength of the root section of the thread segment 5. According to the tightening torque of the bolt 3, the safe shear strength of the root section of the thread segment 5, and the safe bending strength of the root section of the thread segment 5, the effective thread depth of the thread segment is obtained. The acquisition speed is fast, which improves the design speed of the thread segment inside the mounting hole 11, thereby improving the manufacturing efficiency of the reducer housing 1, and solves the problem that the electric drive axle reducer housing with a cast iron structure in the prior art is heavy and difficult to meet the requirements of lightweight automobiles. The electric drive axle reducer housing is manufactured with a lightweight material, and the effective thread depth is different from that of the electric drive axle reducer housing with a cast iron structure. The exhaustive method is slow to test, which reduces the test efficiency and thus reduces the manufacturing efficiency.

[0044] In this example, the single-turn thread layer is expanded along the root to form the thread tooth segment 5, which actually simplifies the single-turn thread layer into a cantilever beam structure. For example, if the single-turn thread layer is expanded along the major diameter D, the thread tooth segment 5 can be regarded as a cantilever beam with a width of πD.

[0045] like Figure 3 As shown, in some optional embodiments, the force analysis of the thread segment 5 to obtain the safe shear strength of the root section of the thread segment 5 and the safe bending strength of the root section of the thread segment 5 includes:

[0046] Adjust the average pressure applied to the circumference of the mid-diameter of the thread tooth segment 5 to obtain a shear strength curve of the root section of the thread tooth segment 5 and a bending strength curve of the root section of the thread tooth segment 5;

[0047] According to the shear strength curve of the root section of the thread segment 5 and the bending strength curve of the root section of the thread segment 5, the safe shear strength of the root section of the thread segment 5 and the safe bending strength of the root section of the thread segment 5 are obtained.

[0048] In this embodiment, the average pressure applied to the circumference of the median diameter of the thread segment 5 is first adjusted to obtain a shear strength curve of the root section of the thread segment 5 and a bending strength curve of the root section of the thread segment 5. According to the shear strength curve of the root section of the thread segment 5 and the bending strength curve of the root section of the thread segment 5, the safe shear strength of the root section of the thread segment 5 and the safe bending strength of the root section of the thread segment 5 are obtained, thereby improving the speed of obtaining the safe shear strength of the root section of the thread segment 5 and the safe bending strength of the root section of the thread segment 5, improving the design speed of the thread segment inside the mounting hole 11, and thereby improving the manufacturing efficiency of the reducer housing 1.

[0049] like Figure 3 As shown, in some optional embodiments, according to the formula: b=0.65P to obtain the safe shear strength of the root section of thread segment 5;

[0050] Among them, t is the safe shear strength of the root section of thread segment 5, Q is the total pressure borne by the thread segment, u is the number of thread layers, πD is the root length of thread segment 5, b is the root thickness of thread segment 5, [t] is the allowable shear stress of the material of thread segment 5, P is the thread pitch, and D is the major diameter of thread segment 5.

[0051] In this embodiment, according to the formula: b=0.65P to obtain the safe shear strength of the root section of thread segment 5; wherein, t is the safe shear strength of the root section of thread segment 5, Q is the total pressure borne by the thread segment, u is the number of thread layers, πD is the root length of thread segment 5, b is the root thickness of thread segment 5, [t] is the allowable shear stress of the material of thread segment 5, P is the thread pitch, and D is the major diameter of thread segment 5. The safe shear strength of the root section of thread segment 5 can be quickly obtained.

[0052] like Figure 3 As shown, in some optional embodiments, according to the formula:

[0053] l=(DD 2 ) / 2, b=0.65P to obtain the safe bending strength of the root section of thread segment 5;

[0054] Among them, σ b is the safety bending strength of the root section of thread segment 5, Q is the total pressure borne by the thread segment, u is the number of thread layers, πD is the root length of thread segment 5, b is the root thickness of thread segment 5, [σ] b is the allowable bending stress of the material of thread segment 5, l is the bending force arm, P is the thread pitch, D is the major diameter of thread segment 5, and D2 is the middle diameter of thread segment 5.

[0055] In this embodiment, according to the formula: l=(DD 2 ) / 2, b = 0.65P to obtain the safe bending strength of the root section of thread segment 5; where σ b is the safety bending strength of the root section of thread segment 5, Q is the total pressure borne by the thread segment, u is the number of thread layers, πD is the root length of thread segment 5, b is the root thickness of thread segment 5, [σ] b is the allowable bending stress of the material of thread segment 5, l is the bending force arm, P is the thread pitch, D is the major diameter of thread segment 5, and D2 is the middle diameter of thread segment 5. The safe bending strength of the root section of thread segment 5 can be quickly obtained.

[0056] In this example, the middle diameter of the thread segment 5 refers to the diameter of the middle circumference of a single turn of the thread layer, and the major diameter of the thread segment 5 refers to the diameter of the outer circumference of a single turn of the thread layer.

[0057] like Figure 3 As shown, in some optional embodiments, the effective thread depth of the thread segment is obtained according to the tightening torque of the bolt 3, the safe shear strength of the root section of the thread segment 5, and the safe bending strength of the root section of the thread segment 5, including:

[0058] According to the safe shear strength of the root section of the thread tooth segment 5 and the safe bending strength of the root section of the thread tooth segment 5, the safe shear strength and safe bending strength of the root section of the single-turn thread layer are obtained;

[0059] According to the tightening torque of the bolt 3, the safe shear strength and safe bending strength of the root section of the single-turn thread layer, the number of thread layers required to withstand the tightening torque of the bolt 3 is obtained;

[0060] Get the effective thread depth of the thread segment based on the number of thread layers.

[0061] In this embodiment, the safe shear strength and safe bending strength of the root section of the single-turn thread layer are obtained according to the safe shear strength of the root section of the thread tooth segment 5 and the safe bending strength of the root section of the thread tooth segment 5. The number of thread layers required to withstand the tightening torque of the bolt 3 is obtained according to the safe shear strength and safe bending strength of the root section of the single-turn thread layer. The effective thread depth of the thread segment is obtained according to the number of thread layers. The acquisition speed is fast, which improves the design speed of the thread segment in the mounting hole 11, thereby improving the manufacturing efficiency of the reducer housing 1.

[0062] In some optional embodiments, after obtaining the effective thread depth of the thread segment, the method further includes obtaining the actual depth of the bolt hole according to the parameters of the bolt 3 and the effective thread depth of the thread segment.

[0063] In this embodiment, after obtaining the effective thread depth of the thread segment, the actual depth of the bolt hole is obtained according to the parameters of the bolt 3 and the effective thread depth of the thread segment, so as to quickly obtain the actual bolt hole depth.

[0064] like Figure 1 , Figure 2 and Figure 3 As shown, on the one hand, the present application also provides an electric drive axle reducer, which includes:

[0065] The reducer housing 1 has mounting holes 11 at both ends of its upper side, and the set effective thread depth of the inner thread section of the mounting hole 11 is designed according to the above-mentioned design method of the bolt hole of the reducer housing;

[0066] The bearing cover 2 is arranged on the upper side of the reducer housing 1. The bearing cover 2 is provided with a connecting hole 21 corresponding to the mounting hole 11. The connecting hole 21 and the threaded section are both used to threadably cooperate with the bolt 3. The bolt 3 passes through the connecting hole 21 and extends into the mounting hole 11 to be connected with the threaded section. The bolt 3 is used to connect the bearing cover 2 and the reducer housing 1.

[0067] When manufacturing the electric drive axle reducer, mounting holes 11 are provided at both ends of the upper side of the reducer housing 1. The set effective thread depth of the threaded section in the mounting hole 11 is designed according to the design method of the bolt hole of the reducer housing. The bearing cover 2 is arranged on the upper side of the reducer housing 1. The bearing cover 2 is provided with a connecting hole 21 corresponding to the mounting hole 11. The connecting hole 21 and the threaded section are both used for threaded cooperation with the bolt 3. The bolt 3 passes through the connecting hole 21 and extends into the mounting hole 11 to be connected with the threaded section. The bolt 3 is used to connect the bearing cover 2 and the reducer housing 1. When designing the effective thread depth, firstly, a model of a single-turn thread layer in the thread segment is established according to the parameters of the bolt 3, and the single-turn thread layer is expanded along the root to form a thread segment 5, and a force analysis is performed on the thread segment 5 to obtain the safe shear strength of the root section of the thread segment 5 and the safe bending strength of the root section of the thread segment 5. According to the tightening torque of the bolt 3, the safe shear strength of the root section of the thread segment 5, and the safe bending strength of the root section of the thread segment 5, the effective thread depth of the thread segment is obtained. The acquisition speed is fast, which improves the design speed of the thread segment inside the mounting hole 11, thereby improving the manufacturing efficiency of the reducer housing 1, and solves the problem that the electric drive axle reducer housing with a cast iron structure in the prior art is heavy and difficult to meet the requirements of lightweight automobiles. The electric drive axle reducer housing is manufactured with a lightweight material, and the effective thread depth is different from that of the electric drive axle reducer housing with a cast iron structure. The exhaustive method is slow to test, which reduces the test efficiency and thus reduces the manufacturing efficiency.

[0068] like Figure 2As shown, in some optional embodiments, a steel sleeve 4 is provided in the mounting hole 11 , the steel sleeve 4 is integrally cast with the reducer housing 1 , and a threaded section is provided on the inner side of the steel sleeve 4 .

[0069] In this embodiment, a steel sleeve 4 is provided in the mounting hole 11. The steel sleeve 4 is cast integrally with the reducer housing 1. A threaded section is provided on the inner side of the steel sleeve 4. The steel sleeve 4 can be prefabricated in advance. During casting, the prefabricated steel sleeve 4 can be used to cast integrally with the reducer housing 1, thereby further improving the efficiency of manufacturing the reducer housing 1.

[0070] In some optional embodiments, the reducer housing 1 is made of aluminum alloy.

[0071] In this embodiment, the reducer housing 1 is made of aluminum alloy. Aluminum alloy has low density but relatively high strength, close to or exceeding high-quality steel, good plasticity, can be processed into various profiles, and has excellent electrical conductivity, thermal conductivity and corrosion resistance.

[0072] In this example, the material of the reducer housing 1 can also be magnesium alloy, titanium alloy, engineering plastic or carbon fiber composite material. Aluminum alloy, magnesium alloy, titanium alloy, engineering plastic or carbon fiber composite material are all lightweight materials, which help to lighten the vehicle.

[0073] like Figure 1 , Figure 2 and Figure 3 As shown, on the other hand, the present application also provides a vehicle, which includes the above-mentioned electric drive axle reducer.

[0074] When manufacturing the electric drive axle reducer, mounting holes 11 are provided at both ends of the upper side of the reducer housing 1. The set effective thread depth of the threaded section in the mounting hole 11 is designed according to the design method of the bolt hole of the reducer housing. The bearing cover 2 is arranged on the upper side of the reducer housing 1. The bearing cover 2 is provided with a connecting hole 21 corresponding to the mounting hole 11. The connecting hole 21 and the threaded section are both used for threaded cooperation with the bolt 3. The bolt 3 passes through the connecting hole 21 and extends into the mounting hole 11 to be connected with the threaded section. The bolt 3 is used to connect the bearing cover 2 and the reducer housing 1. When designing the effective thread depth, firstly, a model of a single-turn thread layer in the thread segment is established according to the parameters of the bolt 3, and the single-turn thread layer is expanded along the root to form a thread segment 5, and a force analysis is performed on the thread segment 5 to obtain the safe shear strength of the root section of the thread segment 5 and the safe bending strength of the root section of the thread segment 5. According to the tightening torque of the bolt 3, the safe shear strength of the root section of the thread segment 5, and the safe bending strength of the root section of the thread segment 5, the effective thread depth of the thread segment is obtained. The acquisition speed is fast, which improves the design speed of the thread segment inside the mounting hole 11, thereby improving the manufacturing efficiency of the reducer housing 1, and solves the problem that the electric drive axle reducer housing with a cast iron structure in the prior art is heavy and difficult to meet the requirements of lightweight automobiles. The electric drive axle reducer housing is manufactured with a lightweight material, and the effective thread depth is different from that of the electric drive axle reducer housing with a cast iron structure. The exhaustive method is slow to test, which reduces the test efficiency and thus reduces the manufacturing efficiency.

[0075] like Figure 4 and Figure 5 As shown, the effective thread depth obtained by the present application can be verified by a tensile test, and after verification, it is confirmed that the effective thread depth designed by the reducer housing bolt hole design method provided by the present application meets the design requirements.

[0076] To sum up, when manufacturing the electric drive axle reducer, mounting holes 11 are provided at both ends of the upper side of the reducer housing 1. The set effective thread depth of the threaded section in the mounting hole 11 is designed according to the design method of the bolt hole of the reducer housing. The bearing cover 2 is arranged on the upper side of the reducer housing 1. The bearing cover 2 is provided with a connecting hole 21 corresponding to the mounting hole 11. The connecting hole 21 and the threaded section are both used for threaded cooperation with the bolt 3. The bolt 3 passes through the connecting hole 21 and extends into the mounting hole 11 to be connected with the threaded section. The bolt 3 is used to connect the bearing cover 2 and the reducer housing 1. When designing the effective thread depth, firstly establish a model of a single-turn thread layer in the thread segment according to the parameters of the bolt 3, and expand the single-turn thread layer along the root to form a thread segment 5, adjust the average pressure applied to the circumference of the median diameter of the thread segment 5, obtain the shear strength curve of the root section of the thread segment 5, and the bending strength curve of the root section of the thread segment 5, obtain the safe shear strength of the root section of the thread segment 5, and the safe bending strength of the root section of the thread segment 5 according to the shear strength curve of the root section of the thread segment 5, and the bending strength curve of the root section of the thread segment 5, obtain the safe shear strength of the root section of the thread segment 5, and the safe bending strength of the root section of the thread segment 5, obtain the safe shear strength and safe bending strength of the root section of the single-turn thread layer, and according to the parameters of the bolt 3 The tightening torque, the safe shear strength and the safe bending strength of the root section of a single-turn thread layer are obtained to obtain the number of thread layers required to withstand the tightening torque of the bolt 3. According to the number of thread layers, the effective thread depth of the thread segment is obtained. According to the parameters of the bolt 3 and the effective thread depth of the thread segment, the actual depth of the bolt hole is obtained. The acquisition speed is fast, which improves the design speed of the thread segment inside the mounting hole 11, thereby improving the manufacturing efficiency of the reducer housing 1, and solves the problem that the electric drive axle reducer housing with a cast iron structure in the prior art is heavy and difficult to meet the requirements of lightweight automobiles. The electric drive axle reducer housing is manufactured with lightweight materials, and the effective thread depth is different from that of the electric drive axle reducer housing with a cast iron structure. The exhaustive test speed is slow, which reduces the test efficiency and thus reduces the manufacturing efficiency.

[0077] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present 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 cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0078] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0079] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for designing bolt holes of a reducer housing, characterized in that: The following steps are involved: A model of a single-turn thread layer in a thread segment is established according to the parameters of the bolt (3), and the single-turn thread layer is expanded along the root to form a thread tooth segment (5); Performing a stress analysis on the threaded tooth segment (5) to obtain the safe shear strength of the root section of the threaded tooth segment (5) and the safe bending strength of the root section of the threaded tooth segment (5); The effective thread depth of the thread segment is obtained based on the tightening torque of the bolt (3), the safe shear strength of the root section of the thread segment (5), and the safe bending strength of the root section of the thread segment (5).

2. A method for designing bolt holes of a reducer housing as claimed in claim 1, characterized in that: The stress analysis of the threaded tooth segment (5) to obtain the safe shear strength of the root section of the threaded tooth segment (5) and the safe bending strength of the root section of the threaded tooth segment (5) includes: Adjusting the average pressure applied to the circumference of the mid-diameter of the threaded tooth segment (5) to obtain a shear strength curve of the root section of the threaded tooth segment (5) and a bending strength curve of the root section of the threaded tooth segment (5); According to the shear strength curve of the root section of the thread tooth segment (5) and the bending strength curve of the root section of the thread tooth segment (5), the safe shear strength of the root section of the thread tooth segment (5) and the safe bending strength of the root section of the thread tooth segment (5) are obtained.

3. A method for designing bolt holes of a reducer housing as claimed in claim 2, characterized in that: According to the formula: b=0.65P to obtain the safe shear strength of the root section of the thread segment (5); Wherein, t is the safety shear strength of the root section of the thread segment (5), Q is the total pressure borne by the thread segment, u is the number of thread layers, πD is the root length of the thread segment (5), b is the root thickness of the thread segment (5), [t] is the allowable shear stress of the material of the thread segment (5), P is the thread pitch, and D is the major diameter of the thread segment (5).

4. A method for designing bolt holes of a reducer housing as claimed in claim 2, characterized in that: According to the formula: l=(DD 2 ) / 2, b=0.65P to obtain the safe bending strength of the root section of the thread segment (5); Among them, σ b is the safety bending strength of the root section of the thread segment (5), Q is the total pressure borne by the thread segment, u is the number of thread layers, πD is the root length of the thread segment (5), b is the root thickness of the thread segment (5), [σ] b is the allowable bending stress of the material of the thread segment (5), l is the bending force arm, P is the thread pitch, D is the major diameter of the thread segment (5), and D2 is the median diameter of the thread segment (5).

5. A method for designing bolt holes of a reducer housing as claimed in claim 1, characterized in that: The method of obtaining the effective thread depth of the thread segment according to the tightening torque of the bolt (3), the safe shear strength of the root section of the thread segment (5), and the safe bending strength of the root section of the thread segment (5) comprises: According to the safe shear strength of the root section of the thread tooth segment (5) and the safe bending strength of the root section of the thread tooth segment (5), the safe shear strength and safe bending strength of the root section of the single-turn thread layer are obtained; According to the tightening torque of the bolt (3), the safe shear strength and the safe bending strength of the root section of a single-turn thread layer, the number of thread layers required to withstand the tightening torque of the bolt (3) is obtained; Get the effective thread depth of the thread segment based on the number of thread layers.

6. A method for designing bolt holes of a reducer housing as claimed in claim 1, characterized in that: After obtaining the effective thread depth of the threaded segment, the method further includes obtaining the actual depth of the bolt hole according to the parameters of the bolt (3) and the effective thread depth of the threaded segment.

7. An electric drive axle reducer, characterized in that: include: The reducer housing (1) has mounting holes (11) at both ends of its upper side, and the internal thread section of the mounting hole (11) has a set effective thread depth. Designed according to a method for designing bolt holes of a reducer housing according to any one of claims 1 to 6; A bearing cover (2) is arranged on the upper side of the reducer housing (1); a connecting hole (21) corresponding to the mounting hole (11) is provided on the bearing cover (2); the connecting hole (21) and the threaded section are both used for threaded cooperation with a bolt (3); the bolt (3) passes through the connecting hole (21) and extends into the mounting hole (11) to be connected with the threaded section; the bolt (3) is used to connect the bearing cover (2) and the reducer housing (1).

8. The electric drive axle reducer according to claim 7, characterized in that: A steel sleeve (4) is arranged in the mounting hole (11); the steel sleeve (4) is cast integrally with the reducer housing (1); and the threaded section is arranged on the inner side of the steel sleeve (4).

9. The electric drive axle reducer according to claim 7, characterized in that: The reducer housing (1) is made of aluminum alloy.

10. A vehicle, characterized in that: It comprises an electric drive axle reducer as described in any one of claims 7 to 9.

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