A method for indirectly measuring the mounting precision of a pure electric vehicle suspension

Abstract

This invention relates to the field of automotive component technology, specifically to a method for indirectly measuring the mounting accuracy of a pure electric vehicle's suspension mount. The method involves measuring the X-axis change ΔX of the suspension mount before and after powertrain mounting; marking three points on the suspension mount: point A, point B, and point C. Points A and B are marked on the outer shell of the suspension mount, while point C is marked on the core of the suspension mount or on the connecting bolt between the suspension arm and the core. A virtual local coordinate system is established with point A as the origin, and the lengths of points AB, BC, AC, BC', and AC' are measured. The Y-axis change ΔY before and after powertrain mounting is calculated, ΔY = Y1 - Y2, and the Z-axis change ΔZ before and after powertrain mounting is calculated, ΔZ = Z2 - Z1. By setting three points on the suspension mount and measuring the distances between these points before and after mounting, the mounting accuracy of the circular bushing-type suspension mount is obtained through calculation of the measured data.

Description

Technical Field

[0001] This invention relates to the field of automotive parts technology, and specifically to a method for indirectly measuring the mounting accuracy of pure electric vehicle suspensions. Background Technology

[0002] In the process of automobile research and development, design and production, in order to ensure the positional accuracy of the powertrain assembly in the engine compartment, it is usually necessary to measure the powertrain mounting accuracy during powertrain assembly. This measurement is mainly to determine the amount of positional change of the powertrain before and after assembly.

[0003] The suspension mount is a major load-bearing component connecting the powertrain to the vehicle body or subframe, typically consisting of three parts: an outer shell, a rubber main spring, and a core. The outer shell and core are usually metal parts, and the outer shell and rubber main spring, as well as the core and rubber main spring, are joined together using a vulcanization process. During vehicle installation, the outer shell of the suspension mount is rigidly connected to the vehicle body or subframe via bolts, and the core is rigidly connected to the suspension arm via bolts. The suspension arm connects to the powertrain. Therefore, the powertrain and the vehicle body or subframe are isolated by the rubber main spring of the suspension mount. The suspension mount supports the weight of the powertrain, mitigates impacts, isolates vibrations, and limits displacement. Before and after the powertrain is connected to the suspension mount, the core and suspension arm of the suspension mount will undergo a certain displacement due to the deformation of the rubber main spring. Measuring this displacement change is called suspension mount accuracy measurement, or suspension mount installation accuracy measurement. In the powertrain mounting accuracy, the change in ΔZ is mainly related to the mass of the powertrain, while the changes in ΔX and ΔY are mainly related to the dimensional deviation of the suspension support, the installation deviation, and the stiffness deviation of the rubber main spring.

[0004] In the measurement of suspension mounting accuracy, if the displacement change is ≤2mm, the mounting condition is considered acceptable; if the displacement change exceeds 2mm (generally not exceeding 5mm), the mounting condition is considered unacceptable. To obtain the suspension mounting accuracy result, a measurement accuracy of ≥0.5mm is usually required; to accurately reflect the level of suspension mounting accuracy, a measurement accuracy of ≥0.2mm is required.

[0005] In practical engineering applications, tools such as rulers and vernier calipers are typically used to measure the mounting accuracy of suspension mounts. However, as pure electric vehicles increasingly adopt center-of-gravity (COG) suspension mounts, and most COG suspension mounts use circular bushing-type mount supports, it is difficult to directly measure this type of mount structure using rulers and vernier calipers in a vehicle assembly environment.

[0006] Therefore, in the existing technology, there is no method for measuring the mounting accuracy of circular bushing-type suspension supports. Summary of the Invention

[0007] The purpose of this invention is to address the deficiency in the existing technology that makes it difficult to directly measure the mounting accuracy of circular bushing-type suspension supports. This invention provides a method for indirectly measuring the mounting accuracy of pure electric vehicle suspensions. By setting three marker points on the suspension support and measuring the distance between the points before and after mounting, the mounting accuracy of the circular bushing-type suspension support is obtained by calculating the measurement data.

[0008] This invention provides a method for indirectly measuring the mounting accuracy of a pure electric vehicle's suspension, comprising the following steps:

[0009] The change in the X direction of the suspension mount before and after the powertrain is installed is measured as ΔX = X2 - X1, where X1 is the gap between the side position of the front suspension arm and the side position of the suspension mount before the powertrain is installed, and X2 is the gap between the side position of the rear suspension arm and the side position of the suspension mount after the powertrain is installed.

[0010] Three markers are marked on the suspension support, namely marker point A, marker point B and marker point C. Marker point A and marker point B are marked on the outer shell of the suspension support, and marker point C is marked on the core of the suspension support or on the connecting bolt between the suspension arm and the core. A virtual local coordinate system is established with marker point A as the origin. The coordinate direction of the virtual local coordinate system is the same as that of the vehicle coordinate system.

[0011] Measure the lengths of markers AB, BC, and AC, as well as the lengths of BC' and AC'. Marker C' is the location of marker C after the powertrain is installed.

[0012] Calculate the change in the Y-axis, ΔY, before and after the powertrain is installed. Where the coordinates of marker point C in the virtual local coordinate system are (Y1, Z1), and the coordinates of marker point C' in the virtual local coordinate system are (Y2, Z2);

[0013] Calculate the Z-axis change ΔZ before and after powertrain installation. ;

[0014] Among them, the X, Y, and Z directions are the three axes of the vehicle coordinate system.

[0015] Preferably, when calculating ΔZ, the effects of ΔX, ΔZ, and the initial angle θ on Z1 and Z2 are also considered, and Z1 and Z2 are corrected to obtain corrected values ​​Z1' and Z2', respectively. This corrects the Z-axis change ΔZ before and after powertrain installation. , where the initial angle θ is the tilt angle of △ABC.

[0016] Preferably, the change in the Y direction ΔY before and after the powertrain is installed is calculated using the following formula:

[0017] ;

[0018] Where AB, AC, AC', BC, BC' are the distance measurements between marker points A, B, C, and C', and θ is the initial angle.

[0019] Preferably, the Z-axis change ΔZ before and after the powertrain is installed is calculated using the following formula:

[0020] ;

[0021] Where AB, AC, AC', BC, BC' are the distance measurements between marker points A, B, C, and C', and θ is the initial angle;

[0022] α' represents the angular change caused by △X. hour, ; hour, ;

[0023] β represents the angular change caused by ΔZ. hour, ; ;

[0024] in, ;

[0025] .

[0026] Preferably, the marker point A and marker point B are at the same height, and the marker point C is equidistant from both marker point A and marker point B.

[0027] Preferably, X1 and X2 are measured using vernier calipers.

[0028] Preferably, the lengths of the marked points AB, BC, and AC, as well as the lengths of BC' and AC', are measured using calipers and rulers.

[0029] The beneficial effects of this invention are as follows:

[0030] 1. By setting three marker points on the suspension support, setting new virtual coordinates, and measuring the distance between the points before and after mounting, the three-dimensional accurate measurement of the mounting accuracy of the circular bushing type suspension support can be achieved, solving the problem of mounting accuracy measurement for pure electric vehicles and accurately reflecting the level of mounting accuracy of the suspension support.

[0031] 2. When calculating ΔZ, the effects of ΔX, ΔZ, and the initial angle θ on Z1 and Z2 are also considered. Z1 and Z2 are corrected, resulting in corrected values ​​Z1' and Z2', respectively. This corrects the Z-axis change ΔZ before and after powertrain installation. This further improves the accuracy of indirect measurements of the mounting accuracy of pure electric vehicles. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the process of the present invention;

[0033] Figure 2 This is a schematic diagram of the vehicle assembly of the suspension support of the present invention;

[0034] Figure 3 This is a front view of the suspension support and suspension arm of the present invention;

[0035] Figure 4 This is a side view of the suspension support and suspension arm of the present invention;

[0036] Figure 5 This is a schematic diagram of the marking points during the accuracy measurement of the suspension support of the present invention;

[0037] Figure 6 A schematic diagram showing the displacement of the marked points during precision measurement of the suspension support.

[0038] Figure 7 A two-dimensional coordinate diagram showing the relationship between the mounting accuracy of the suspension support in the Y and Z directions;

[0039] Figure 8 A three-dimensional coordinate diagram illustrating the influence of a single factor—powertrain mounting accuracy △X—on the included angles of △ABC and △ABC'.

[0040] Figure 9 This is a two-dimensional coordinate diagram illustrating the influence of a single factor—powertrain mounting accuracy △X≤ 0—on the included angles of △ABC and △ABC'.

[0041] Figure 10 For single-factor powertrain assembly precision A two-dimensional coordinate diagram illustrating the influence of time on the included angle between △ABC and △ABC';

[0042] Figure 11 A three-dimensional coordinate diagram illustrating the influence of the initial position angle θ of a single-factor marker point C on the included angle between △ABC and △ABC'.

[0043] Figure 12 This is a two-dimensional coordinate diagram illustrating the influence of the initial position angle θ≤ 0 of a single-factor marker point C on the included angle between △ABC and △ABC'.

[0044] Figure 13 The initial position angle of the single-factor marker point C A two-dimensional coordinate diagram illustrating the influence of time on the included angle between △ABC and △ABC';

[0045] Figure 14 for A two-dimensional coordinate diagram illustrating the influence of a single factor—powertrain mounting accuracy △Z—on the included angles of △ABC and △ABC'.

[0046] Figure 15 for A two-dimensional coordinate diagram illustrating the influence of a single factor—powertrain mounting accuracy △Z—on the included angles of △ABC and △ABC'.

[0047] In the diagram: 1-subframe, 2-connecting bolts between the suspension mount and the subframe, 3-suspension mount housing, 4-suspension mount rubber main spring, 5-suspension mount core, 6-connecting bolts between the suspension arm and the core, 7-suspension arm, 8-connecting bolts between the suspension arm and the powertrain, 9-powertrain, 10-suspension mount, 11-mark point A, 12-mark point B, 13-mark point C, 14-mark point C', 15-side position of the suspension mount, 16-side position of the powertrain mounted on the rear suspension arm, 17-side position of the powertrain mounted on the front suspension arm. Detailed Implementation

[0048] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0049] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0050] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0051] References to "one embodiment" or "some embodiments" in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized. "A plurality" means "two or more."

[0052] This invention provides a method for indirectly measuring the mounting accuracy of a pure electric vehicle's suspension, comprising the following steps:

[0053] The change in the X direction of the suspension mount before and after the powertrain is installed is measured as ΔX = X2 - X1, where X1 is the gap between the side position of the front suspension arm and the side position of the suspension mount before the powertrain is installed, and X2 is the gap between the side position of the rear suspension arm and the side position of the suspension mount after the powertrain is installed.

[0054] Three markers are marked on the suspension support, namely marker point A, marker point B and marker point C. Marker point A and marker point B are marked on the outer shell of the suspension support, and marker point C is marked on the core of the suspension support or on the connecting bolt between the suspension arm and the core. A virtual local coordinate system is established with marker point A as the origin. The coordinate direction of the virtual local coordinate system is the same as that of the vehicle coordinate system.

[0055] Measure the lengths of markers AB, BC, and AC, as well as the lengths of BC' and AC'. Marker C' is the location of marker C after the powertrain is installed.

[0056] Calculate the change in the Y-axis, ΔY, before and after the powertrain is installed. Where the coordinates of marker point C in the virtual local coordinate system are (Y1, Z1), and the coordinates of marker point C' in the virtual local coordinate system are (Y2, Z2);

[0057] Calculate the Z-axis change ΔZ before and after powertrain installation. ;

[0058] Among them, the X, Y, and Z directions are the three axes of the vehicle coordinate system.

[0059] Example 1

[0060] This embodiment provides a preferred implementation method, as detailed below.

[0061] Figure 2 This is a schematic diagram of the vehicle assembly of the suspension mount, with the coordinate system shown representing the vehicle's coordinates. The suspension mount 10 includes a suspension mount housing 3, a suspension mount core 5, and a suspension mount rubber main spring 4. The suspension mount housing 3 and the suspension mount rubber main spring 4 are connected together via a vulcanization process, as are the suspension mount core 5 and the suspension mount rubber main spring 4 via a vulcanization process. The suspension arm 7 is connected to the suspension mount core 5 via a connecting bolt 6 between the suspension arm and the core. During vehicle assembly, the suspension arm 7 is connected to the powertrain 9 via a connecting bolt 8 between the suspension arm and the powertrain, and the suspension mount 10 is connected to the subframe 1 via a connecting bolt 2 between the suspension mount and the subframe.

[0062] Before the powertrain 9 is installed, the suspension arm 7 is connected to the suspension mount 10 and mounted on the subframe 1. The rubber main spring of the suspension mount bears almost no weight. After the powertrain is installed, the suspension arm is connected to the powertrain, and the rubber main spring 4 of the suspension mount 10 needs to bear the weight of the powertrain 9 and deforms. Since the suspension arm 7, the suspension mount core 5, and the powertrain 9 are connected by the suspension arm and powertrain connecting bolts 8, which is a rigid connection, they will move together with the powertrain 9. Therefore, the installation accuracy of the powertrain 9 can be equivalent to the positional change of the suspension arm 7, the suspension mount core 5, or the suspension arm and core connecting bolts 6.

[0063] Figure 3 , 4 The images show the front and side views of the suspension mount 10 and suspension arm 7. The change in the X-direction ΔX of the suspension mount 10 before and after the powertrain 9 is mounted can be directly obtained by measuring the distance between the side position 17 of the suspension arm and the side position 15 of the suspension mount before the powertrain is mounted. Before the powertrain 9 is mounted, the gap X1 between the side position 17 of the suspension arm and the side position 15 of the suspension mount is measured and recorded using vernier calipers; after the powertrain 9 is mounted, the gap X2 between the side position 16 of the suspension arm and the side position 15 of the suspension mount is measured and recorded using vernier calipers.

[0064] The change before and after the installation of powertrain 9 is ΔX = X2 - X1. When ΔX > 0, it means that the powertrain 9 moves towards the X+ direction after installation; when ΔX < 0, it means that the powertrain 9 moves towards the X- direction after installation.

[0065] Figure 5This diagram illustrates the marking points for measuring the accuracy of the suspension mount installation. Before installing the powertrain 9, three marking points need to be marked on the suspension mount 10: A11, B12, and C13. Marking point C13 is marked on the suspension mount core 5 or on the connecting bolt 6 between the suspension arm and the core. Marking points A11 and B12 are at the same height, and marking point C13 is equidistant from both A11 and B12, meaning that marking point C13 should ideally be directly above A11 and B12 (partial deviation is permissible). A virtual local coordinate system is established with marking point A11 as the origin, and the coordinate direction of this virtual local coordinate system is the same as that of the vehicle coordinate system. The displacements ΔY and ΔZ before and after powertrain 9 installation represent the changes in the coordinate values ​​of marking point C13 in the virtual local coordinate system plane YAZ. The lengths of AB, BC, and AC are measured and recorded using calipers and a ruler.

[0066] Figure 6 This diagram illustrates the displacement of the marker point during the accuracy measurement of the suspension support. After the powertrain 9 is installed, marker point C13 will shift due to the weight of the powertrain 9. Assuming the shifted position of marker point C13 is marker point C'14, the lengths of BC' and AC' are measured and recorded using calipers and a ruler.

[0067] Figure 7 This is a two-dimensional coordinate diagram illustrating the relationship between the mounting accuracy of the suspension support in the Y and Z directions. △Y represents the change in the Y direction before and after the installation of powertrain 9, and △Z represents the change in the Z direction before and after the installation of powertrain 9. Before the installation of powertrain 9, the coordinates of point C13 in the two-dimensional coordinate system are (Y1, Z1); the coordinates of point C'14 in the two-dimensional coordinate system are (Y2, Z2). D is the height of triangle ABC passing through point C, and D' is the height of triangle ABC' passing through point C'. Based on trigonometric relationships, we know that:

[0068] , (Formula 1)

[0069] , (Formula 2)

[0070] Inside triangle ABC, since AB, AC, and BC are all known quantities, according to the Law of Cosines:

[0071]

[0072] but:

[0073] (Formula 3)

[0074] Similarly, within △ABC', we can obtain:

[0075] (Formula 4)

[0076] When both C and C' are on the YAZ coordinate plane, according to the direction of the coordinate system:

[0077] (Formula 5)

[0078] (Formula 6)

[0079] When △Y>0, it means that after the powertrain 9 is installed, it will shift to Y+ in the vehicle coordinate system; when △Y<0, it means that after the powertrain 9 is installed, it will shift to Y- in the vehicle coordinate system.

[0080] When △Z>0, it means that after the powertrain 9 is installed, it will shift to Z+ in the vehicle coordinate system; when △Z<0, it means that after the powertrain 9 is installed, it will shift to Z- in the vehicle coordinate system.

[0081] Since factors such as the accuracy ΔX and ΔZ of the powertrain 9 and the initial angle θ will directly or indirectly have a significant impact on Z1 and Z2, the established numerical model needs to correct Z1 and Z2. Assuming that the corrected values ​​of Z1 and Z2 are Z1' and Z2' respectively, the final value of ΔZ is:

[0082] (Formula 7)

[0083] The following shows the influence of different factors on the coordinate values ​​Z1 and Z2, and the derivation of the numerical models for Z1' and Z2':

[0084] (1) The effect of △X

[0085] Figure 8 This is a three-dimensional coordinate diagram illustrating the effect of a single factor—powertrain installation accuracy △X—on the angle between △ABC and △ABC'. When the powertrain 9 is installed and only produces a change in △X, this change will affect the angle between △ABC' and the coordinate plane YAZ. α is the change in the angle caused by △X. Figure 9 , 10 This is a two-dimensional coordinate diagram illustrating the influence of a single factor—powertrain mounting accuracy ΔX—on the angle between ΔABC and ΔABC'. When ΔX ≤ 0, α is defined as negative; when ΔX > 0, α is defined as positive. Based on trigonometric relationships:

[0086]

[0087] but

[0088] (Formula 8)

[0089] Angle α directly affects the angle between △ABC' and the coordinate plane YAZ after the powertrain 9 is installed, and thus indirectly affects the change of coordinate value Z2'.

[0090] (2) Influence of initial angle θ

[0091] Figure 11 This is a three-dimensional coordinate diagram illustrating the influence of the initial position angle of marker point C on the angle between triangles ABC and ABC'. θ is the angle between △ABC and the coordinate plane YAZ, i.e., the initial angle. When the initial marker point C13 is not located within the coordinate plane YAZ, i.e., point C is not directly above the line AB, C1 is the perpendicular projection of marker point C13 onto plane YAZ. In this case, the actual height of CD on the coordinate plane YAZ is C1D. From trigonometric relationships, we know that:

[0092] (Formula 9)

[0093] Figure 12 , 13 This is a two-dimensional coordinate diagram illustrating the influence of the initial position angle of marker point C on the included angle between triangles ABC and ABC'. When point C is after line AB (i.e., C is after C1), θ is defined as a negative value; when point C is before line AB (i.e., C is before C1), θ is defined as a positive value. The initial angle θ affects both coordinate values ​​Z1' and Z2'.

[0094] When the initial angle θ≤0, a negative angle α will increase the angle between △ABC, △ABC' and the coordinate system plane YAZ, while a positive angle α will decrease the angle between △ABC, △ABC' and the coordinate system plane YAZ.

[0095] When the initial angle θ > 0, a negative angle α will decrease the angle between △ABC, △ABC' and the coordinate plane YAZ, while a positive angle α will increase the angle between △ABC, △ABC' and the coordinate plane YAZ. Therefore, we can let:

[0096] (Formula 10)

[0097] (Formula 11)

[0098] Therefore, the influence of angle α on the coordinate value Z2' can ultimately be transformed into the influence of angle α'.

[0099] (3) The influence of △Z

[0100] Figure 14 , 15This is a two-dimensional coordinate diagram illustrating the influence of a single factor—powertrain installation accuracy △Z—on the angle between △ABC and △ABC'. E is the intersection point (i.e., the perpendicular point) of CC' and the X-axis. The initial angle of △ABC is θ. When the powertrain 9 is installed and only the change in △Z occurs, this change will affect the angle between △ABC' and the coordinate plane YAZ. β is the change in angle caused by the action of △Z. According to trigonometric relationships:

[0101] (Formula 11)

[0102] (Formula 12)

[0103] Based on the influence of the above factors, a mathematical model for Z2' can be established and solved:

[0104] (Formula 13)

[0105] Finally, from (Formula 1-13), we can obtain:

[0106] (Formula 14)

[0107] (Formula 15)

[0108] in:

[0109] X1, X2 — are the measured values ​​in the X direction, known quantities;

[0110] AB, AC, AC', BC, BC' — These are known quantities representing the distance measurements between marked points A, B, and C.

[0111] θ — the initial angle, a known quantity.

[0112] α' — the angular change caused by △X. ; .

[0113] β — the angle change caused by ΔZ. ;

[0114]

[0115] , known quantities.

[0116] , known quantities.

[0117] Based on the mathematical model established in this invention (Formulas 14-16), the effectiveness of the mathematical model was studied when the powertrain experienced a combined limit displacement variation of ±5mm in the X, Y, and Z directions, as shown in Table 1 below. Table 1 shows that, under the combined limit conditions of suspension mounting accuracy measurement, the maximum error between the calculated values ​​ΔY and ΔZ obtained from the mathematical model in this invention and the actual values ​​ΔY and ΔZ does not exceed 3%, meaning that the calculation accuracy of the mathematical model is greater than 0.15mm, and it can accurately reflect the level of suspension support mounting accuracy.

[0118] Table 1. Differences between calculated and actual values ​​of suspension mounting accuracy from the mathematical model.

[0119]

[0120] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the specific order or hierarchy described.

[0121] In the above detailed description, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features of the single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0122] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0123] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as it is used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

[0124] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for indirectly measuring the mounting accuracy of a pure electric vehicle's suspension, characterized in that, Includes the following steps: The change in the X direction of the suspension mount (10) before and after the powertrain (9) is mounted is measured as ΔX, where ΔX = X2 - X1, X1 is the gap between the side position (17) of the front suspension arm and the side position (15) of the suspension mount, and X2 is the gap between the side position (16) of the rear suspension arm and the side position (15) of the suspension mount. Three marking points are made on the suspension support (10), namely marking point A (11), marking point B (12) and marking point C (13). Marking point A (11) and marking point B (12) are marked on the outer shell (3) of the suspension support, and marking point C (13) is marked on the core (5) of the suspension support or on the connecting bolt (6) between the suspension arm and the core. A virtual local coordinate system is established with marking point A (11) as the origin. The coordinate direction of the virtual local coordinate system is the same as that of the whole vehicle coordinate system. Measure the lengths of markers AB, BC, and AC, as well as the lengths of BC' and AC', where marker C' (14) is the position of marker C (13) after it is mounted on the powertrain (9); Calculate the Y-axis change ΔY before and after the powertrain (9) is installed. , where the coordinates of marker point C (13) in the virtual local coordinate system are (Y1, Z1), and the coordinates of marker point C' (14) in the virtual local coordinate system are (Y2, Z2); Calculate the Z-axis change ΔZ before and after the powertrain (9) is installed. ; Among them, the X, Y, and Z directions are the three axes of the vehicle coordinate system; When calculating △Z, the effects of △X, △Z, and the initial angle θ on Z1 and Z2 are also considered. Z1 and Z2 are corrected, and the corrected values ​​are Z1' and Z2', respectively. Thus, the Z-direction change △Z before and after the powertrain (9) is corrected. , where the initial angle θ is the tilt angle of △ABC.

2. The method for indirectly measuring the mounting accuracy of a pure electric vehicle suspension according to claim 1, characterized in that, The change in the Y direction ΔY before and after the powertrain (9) is installed is calculated using the following formula: ； Where AB, AC, AC', BC, BC' are the distance measurements between marker points A, B, C, and C', and θ is the initial angle.

3. The method for indirectly measuring the mounting accuracy of a pure electric vehicle suspension according to claim 1, characterized in that, The Z-axis change ΔZ before and after the powertrain (9) is installed is calculated using the following formula: ； Where AB, AC, AC', BC, BC' are the distance measurements between marker points A, B, C, and C', and θ is the initial angle; α' represents the angular change caused by △X. hour, ; hour, ; β represents the angular change caused by ΔZ. hour, ; ; in, ; 。 4. The method for indirectly measuring the mounting accuracy of a pure electric vehicle suspension according to claim 1, characterized in that: The marker point A (11) is at the same height as the marker point B (12), and the marker point C (13) is at the same distance from the marker points A (11) and B (12).

5. The method for indirectly measuring the mounting accuracy of a pure electric vehicle suspension according to claim 1, characterized in that: X1 and X2 were measured using vernier calipers.

6. The method for indirectly measuring the mounting accuracy of a pure electric vehicle suspension according to claim 1, characterized in that: The lengths of the marked points AB, BC, and AC, as well as the lengths of BC' and AC', were measured using calipers and rulers.

Images