JP2010217110A - Method for creating drive shaft assy model - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To create a CAE model for vibration analysis of a drive shaft assy in a rotating state around an axial line and attain easy and highly precise creation of the CAE model. <P>SOLUTION: The torque working in the rotational direction and break angle direction at an arbitrary position on a drive shaft 1 is modeled as the CAE model for vibration analysis of the drive shaft assy. In the torque model, spring constants and attenuation coefficient are determined, based on test results of an oscillating test with the drive shaft assy rotated around the axial line, therefore, correspond to those of the case when the drive shaft assy is rotating; consequently the CAE model as well corresponds to the case when the drive shaft assy is rotating. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive shaft assembly model creation method for creating a CAE model for vibration analysis.

  2. Description of the Related Art In recent years, at the vehicle design stage, vehicle vibration and noise generation conditions have been evaluated using finite element analysis using a CAE (Computer Aided Engineering) model of the entire vehicle. According to such a method, the number of actual machine experiments can be greatly reduced, and the design period and man-hours can be reduced. A CAE model of the entire vehicle is created by individually creating a CAE model for each component such as an engine, a transmission, and a suspension, and integrating the CAE models of these components.

  When analyzing vibration transmitted from the engine to the suspension, it is necessary to model a drive shaft that transmits engine power to the drive wheels. As is well known, a constant velocity joint is installed on the drive shaft to allow the drive wheels to move up and down by the suspension. Modeling of the drive shaft involves the entire drive shaft assembly including the constant velocity joint. There is a need to do.

  By the way, a CAE model of a conventional constant velocity joint is created so as to analyze forces acting on each component of the joint. Therefore, in order to create a CAE model, it is necessary to create the internal structure of the constant velocity joint in detail, and to define the gaps, friction, and contact between each component, and the creation is difficult and difficult. It is expensive.

  Patent Document 1 describes that a natural vibration of a mechanical structure can be obtained easily and with sufficient accuracy by modeling a bearing and a speed reducer as a 6-DOF spring element. . Therefore, by applying this, it is also conceivable to model the constant velocity joint of the drive shaft as a spring element having the same six degrees of freedom. However, in such a case, it becomes a problem how to properly define the physical property values such as the mounting position of each spring, the spring constant, and the torsional rigidity in the model, and it becomes difficult to create a highly accurate CAE model. In addition, the model must also take into account the elastic change of the drive shaft itself, and eventually the model to be created becomes complicated.

  Therefore, as disclosed in Patent Document 2, it has been proposed to model a constant velocity joint as a spring element including an elastic change of the drive shaft. In this case, the drive shaft itself can be regarded as a completely rigid body. Therefore, the model can be simplified, and the CAE model for vibration analysis of the drive shaft assembly can be created easily and with high accuracy.

  When modeling the constant velocity joint, specifically, one of the two constant velocity joints on the drive shaft on the engine side and the suspension side is connected to the translation spring in the axial direction of the drive shaft. Model with a rotary spring around the axis of the shaft, and model the other with a rotary spring around the axis. In addition, for each spring constant of the translation spring and the rotary spring used in the modeling, an excitation test using an actual drive shaft assembly is performed, and the axial direction of the entire drive shaft assembly and the shaft The spring constant in the straight direction is calculated and obtained from the calculation result and the design specification values of the drive shaft assembly.

  Incidentally, in Patent Document 2, the vibration test using the actual drive shaft assembly is performed after the rotation of the drive shaft assembly in the axial direction is made non-rotating. Specifically, with the torsional torque applied from one end of the drive shaft assembly, input vibration in the axial direction or axial direction from the same end, and measure the vibration at the other end of the drive shaft assembly. Thus, the vibration test is performed. For this reason, the created CAE model for drive shaft assembly vibration analysis corresponds to a non-rotating state with respect to the rotation of the drive shaft assembly about the axial direction.

JP-A-9-189601 JP 2009-26128 A (FIG. 2)

  As shown in Patent Document 2, by creating a CAE model for vibration analysis of a drive shaft assembly, for vibration analysis of the drive shaft assembly corresponding to a case where rotation around the axial direction of the drive shaft assembly is in a non-rotation state The CAE model can be created easily and with high accuracy. However, with respect to the drive shaft assembly, for example, the drive shaft may rotate around the axis of the drive shaft assembly in a state where the bending angle of the drive shaft with respect to the constant velocity joint is larger than “0”. The CAE model created as described above is not appropriate as the CAE model for vibration analysis of the drive shaft assembly when such movement is performed. This is because the created CAE model is created to correspond to the rotation of the drive shaft assembly around the axial direction in a non-rotating state.

  The present invention has been made in view of such circumstances, and an object of the present invention is to create a CAE model for vibration analysis of a drive shaft assembly in a state of rotating around an axis, and the CAE model. It is an object of the present invention to provide a method for creating a drive shaft model that can be easily and highly accurately created.

In the following, means for achieving the above object and its effects are described.
In order to achieve the above object, according to the first aspect of the present invention, in creating a CAE model for vibration analysis of a drive shaft assembly having constant velocity joints on the input side and output side of the drive shaft, the elasticity of the drive shaft is generated. In the drive shaft assembly model creation method in which the constant velocity joint is modeled as a spring element including changes, and the CAE model is created using the constant velocity joint model, the drive shaft assembly is rotated around an axis. In this state, an excitation test is performed to apply axial vibration and axial vibration to the input shaft of the drive shaft assembly. From the result of the test and the design specification values of the drive shaft assembly, Determine the spring constant and damping coefficient of the constant velocity joint. Arbitrary position on the shaft is the constant velocity joint on the input side of the drive shaft as the origin, and the rotation angle of the drive shaft assembly in the input rotation direction and the bending angle of the drive shaft with respect to the constant velocity joint are declination, respectively. The rotation angle and the bending angle are formulated by defining a spherical coordinate having a moving radius from the origin to an arbitrary position on the drive shaft, and an arbitrary position on the drive shaft is defined as the CAE model. The torque acting in the rotation direction of the shaft is modeled as a torque depending on the rotation angle, its angular velocity, and a spring constant and a damping coefficient for the rotation direction of the spring element, and the drive at the arbitrary position. Torque acting in the direction of the bending angle of the constant velocity joint of the shaft , The angular velocity, as well as modeled as a torque which depends on the spring constant and damping coefficient for the bending angle direction of the spring element.

  According to the above method, as the CAE model for vibration analysis of the drive shaft assembly, the torque acting in the rotation direction at an arbitrary position on the drive shaft and the torque acting in the bending angle direction at the above position are modeled. Further, in these torque models, the respective spring constants for the rotation direction and the bending angle direction of the drive shaft in the constant velocity joint modeled as a spring element, and the rotation direction and the bending angle direction of the drive shaft in the constant velocity joint. Are used. These spring constants and damping coefficients are obtained based on the results of a vibration test performed with the drive shaft assembly rotated about the axis. For this reason, the spring constant and damping coefficient used in the torque model correspond to the rotation of the drive shaft assembly, and the CAE model for vibration analysis created using the model also corresponds to the rotation of the drive shaft assembly. Will be. As described above, the CAE model for vibration analysis of the drive shaft assembly in a state of rotating around the axis can be created, and the CAE model can be created easily and with high accuracy.

  Note that the spring constant and damping coefficient of the constant velocity joint modeled as a spring element are obtained by performing a rotation order analysis on the result of the vibration test as described in claim 2, and transmitting the vibration characteristics of the entire drive shaft assembly. Can be calculated from the transmission characteristics and the design specifications of the drive shaft assembly. As a result, the spring constant and the damping coefficient can be calculated with high accuracy.

A sectional view showing the whole drive shaft assembly of this embodiment. 1 is a schematic diagram showing an embodiment of an excitation test for creating a CAE model for vibration analysis of a drive shaft assembly. (A)-(c) is a graph which shows an example of the test result in the said vibration test. The graph which shows an example of the analysis result when performing the rotation order analysis regarding the transmission load in the case of vibration based on the result of the said vibration test. (A) and (b) respectively show the transition with respect to the rotational speed change of the assembly in the equivalent rigidity of the entire drive shaft assembly obtained from the test result of the vibration test and the analysis result of the rotational order analysis, and the excitation frequency. The graph which shows transition with respect to change. Schematic showing spherical coordinates for defining an arbitrary position on the drive shaft.

Hereinafter, an embodiment in which the present invention is embodied in a model for creating a model of a drive shaft assembly for an automobile will be described with reference to FIGS.
As shown in FIG. 1, the drive shaft assembly includes a sliding tri-board type constant velocity joint 2 on the input side (left side in the figure) of the drive shaft 1 and on the output side (right side in the figure) of the drive shaft 1. A bar field type constant velocity joint 3 is provided.

  The tri-board type constant velocity joint 2 includes a shaft portion 4 that is an input shaft of the drive shaft assembly, an outer race 5 that is positioned on the same axis as the shaft portion 4 and rotates integrally with the coaxial portion 4, and the outer race 5 And a tri-board 6 that is fixed to the input side of the drive shaft 1. The tri-board 6 is provided with a total of three roller shafts 7 (only one is shown in FIG. 1) extending radially with respect to the axis of the drive shaft 1 at equal intervals in the circumferential direction of the drive shaft 1. . A roller 8 is rotatably attached to the roller shaft 7. Each of the rollers 8 is accommodated in a groove 9 formed in the outer race 5 so as to extend in the axial direction of the drive shaft 1. The tri-board type constant velocity joint 2 having the above structure allows the drive shaft 1 to move in a direction approaching and separating from the equivalent velocity joint 2 and extends on the same axis with respect to the shaft portion 4 of the constant velocity joint 2. Can be tilted so as to be bent with respect to the shaft portion 4, and can rotate integrally with the constant velocity joint 2 while performing the movement and the tilt.

  The Barfield type constant velocity joint 3 includes a shaft portion 10 that is an output shaft of the drive shaft assembly, an outer race 11 that is positioned on the same axis line of the shaft portion 10 and rotates integrally with the coaxial portion 10, and the outer race 11 And an inner race 12 fixed to the output side of the drive shaft 1. Between the inner race 12 and the outer race 11, a plurality of balls 14 (only one is shown in FIG. 2) held so as to be able to roll by a holding ring 13 are provided in the circumferential direction of the drive shaft 1. It is provided at intervals. By the bar field type constant velocity joint 3 having the above-described structure, the drive shaft 1 can be tilted so as to be bent with respect to the shaft portion 10 from the state extending on the same axis with respect to the shaft portion 10 of the equivalent speed joint 3. Further, it is possible to rotate integrally with the constant velocity joint 3 while performing the above inclination.

Next, creation of a CAE model for vibration analysis of the drive shaft assembly will be described.
In this embodiment, the constant velocity joints 2 and 3 are modeled as spring elements including the elastic change of the drive shaft 1 with the intention of creating the CAE model easily and with high accuracy. Create the CAE model. In this case, since the drive shaft 1 itself can be regarded as a completely rigid body, the model can be simplified, and the CAE model for vibration analysis of the drive shaft assembly can be created easily and with high accuracy. . In creating the CAE model, specifically, the CAE model is created including the following procedures [1] to [3].

[1] In order to obtain the spring constant and damping coefficient of the constant velocity joints 2 and 3 modeled as spring elements, an excitation test using an actual drive shaft assembly is performed.
FIG. 2 schematically shows an embodiment of a vibration test using an actual drive shaft assembly. In the vibration test, the shaft portion 4 of the constant velocity joint 2 on the input side in the drive shaft assembly is connected to the motor 15, and the shaft portion 10 of the constant velocity joint 3 on the output side is connected to the motor 16. The bend angle α, which is the angle of the drive shaft 1 with respect to the shaft portion 4 of the constant velocity joint 2, is set to an initial value α 0, and the drive shaft assembly is rotated around the axis by driving the motor 15 in this state. A load torque is applied to the drive shaft assembly through driving of the motor 16. Furthermore, vibration in the axial direction (left and right direction in the figure) and vibration in the direction perpendicular to the axis (up and down direction in the figure) are applied to the input shaft of the drive shaft assembly (shaft portion 4 of the constant velocity joint 2). During this test, the rotation mode of the constant velocity joint 2 on the input side of the drive shaft assembly is measured by the tachometer 17, and vibration from the constant velocity joint 2 on the input side of the drive shaft assembly to the constant velocity joint 3 on the output side is measured. The transmission mode is measured by the 6-component force meter 18.

  An example of the result of such an excitation test is shown in FIG. (A) to (c) in the figure show changes in the number of revolutions per minute of the drive shaft assembly, changes in the excitation displacement of the constant velocity joint 2, and changes in the load acting on the constant velocity joint 2, respectively. ing. By the way, the test results shown in the figure show that the excitation direction is the axial direction, the load torque is 200 Nm, the excitation frequency is 40 Hz, and the excitation amplitude is 0.30 mm. This is when the test was conducted. Then, the spring constant and damping coefficient of the constant velocity joints 2 and 3 modeled as spring elements are obtained using the test results obtained when the above-described vibration test is performed and the design specifications of the drive shaft assembly. It is done.

  More specifically, a rotation order analysis regarding the transmission load at the time of vibration is performed based on the result of the vibration test. FIG. 4 shows an example of the analysis result in the rotation order analysis. From the analysis result of the rotational order analysis, the vibration transmission characteristics of the entire drive shaft assembly are obtained. Note that, when the vibration transmission characteristics of the entire drive shaft assembly are obtained in this way, the equivalent rigidity of the entire drive shaft assembly is used. In FIG. 5, (a) and (b) respectively show the transition of the equivalent stiffness of the entire drive shaft assembly obtained from the test result of the excitation test and the analysis result of the rotation order analysis, and the acceleration The change with respect to the change of the vibration frequency is shown. The spring constant and damping of the constant velocity joints 2 and 3 modeled as spring elements from the transmission characteristics of the vibration of the entire drive shaft assembly obtained as described above and the design specifications of the drive shaft assembly. A coefficient is determined.

  Incidentally, the spring constant K of the constant velocity joints 2 and 3 modeled as spring elements can be obtained by solving the following relational expressions (1) and (2).

上式（１）、（２）において、ドライブシャフト１の長さＬ、重量Ｍ、慣性モーメントＪ、及び入力側及び出力側の等速ジョイント２，３の片持ち剛性ｋ1 ，ｋ2 は、ドライブシャフトアッシーの設計諸元値である。等速ジョイント２，３のばね定数Ｋは、上式（１）、（２）をそのばね定数Ｋについて解くことで求めることができる。

In the above formulas (1) and (2), the length L, the weight M, the moment of inertia J of the drive shaft 1 and the cantilever k1 and k2 of the constant velocity joints 2 and 3 on the input side and the output side are as follows: It is the design specification value of Assy. The spring constant K of the constant velocity joints 2 and 3 can be obtained by solving the above equations (1) and (2) for the spring constant K.

  [2] In order to formulate the rotation angle θ in the input rotation direction of the drive shaft assembly (the rotation direction of the shaft portion 4 of the constant velocity joint 2) and the bending angle α of the drive shaft 1 with respect to the shaft portion 4 of the constant velocity joint 3 An arbitrary position on the drive shaft 1 is defined by spherical coordinates.

  FIG. 6 shows spherical coordinates for defining the arbitrary position. In this spherical coordinate, the end of the shaft portion 4 of the constant velocity joint 3 on the drive shaft 1 side is the origin, and the rotation angle θ in the rotation direction of the shaft portion 4 and the bending angle α with respect to the coaxial portion 4 of the drive shaft 1 are defined. Each of them is a declination, and the moving radius is from the origin to any position on the drive shaft 1. Then, by defining an arbitrary position on the drive shaft 1 by the spherical coordinates, the rotation angle θ and the bending angle α can be formulated as shown in the following equations (3) and (4). it can.

また、回転角θ及び折れ角αを上記のように定式化することにより、回転角θの角速度ｄθ／ｄｔ及び折れ角αの角速度ｄα／ｄｔを以下の式（５）、（６）に示されるように定式化することができる。

Further, by formulating the rotation angle θ and the bending angle α as described above, the angular velocity dθ / dt of the rotation angle θ and the angular velocity dα / dt of the bending angle α are expressed by the following equations (5) and (6). Can be formulated.

［３］ドライブシャフトアッシーの振動解析用のＣＡＥモデルとして、ドライブシャフト１上の任意の位置に作用するトルクをモデル化する。

[3] A torque acting on an arbitrary position on the drive shaft 1 is modeled as a CAE model for vibration analysis of the drive shaft assembly.

  Specifically, the torque Tθ acting in the rotation direction of the shaft 1 at an arbitrary position on the drive shaft 1 is converted into the rotation angle θ, the angular velocity dθ / dt, and the constant velocity joints 2 and 3 modeled as spring elements. Modeled as a torque depending on the spring constant kθ and the damping coefficient cθ in the rotation direction. Further, the torque Tα acting in the bending angle direction of the drive shaft 1 at the arbitrary position is defined by the bending angle α, the angular velocity dα / dt, and the bending angle of the constant velocity joints 2 and 3 modeled as spring elements. Modeled as a torque that depends on the spring constant kα and damping coefficient cα in the direction. The torques Tθ and Tα thus modeled are expressed by the following equations (7) and (8), respectively.

なお、上述した［１］〜［３］の手順も含めて作成された上記ＣＡＥモデルを用いてドライブシャフトアッシーの振動解析を行うことにより、ドライブシャフトアッシーにおける入力側から軸方向や軸直方向への振動が入力される際に同ドライブシャフトアッシーの出力側に作用する荷重を定式化することが可能になる。このように、ドライブシャフトアッシーの出力側に作用する荷重としては、出力側の等速ジョイント３に対し軸直方向（軸部１０の軸線方向）に作用する軸直方向荷重Ｆthや、同等速ジョイント３に対しドライブシャフト１の折れ方向に作用する折れ方向荷重Ｆbeがあげられる。これら軸直方向荷重Ｆth及び折れ方向荷重Ｆbeは、上記ＣＡＥモデルを用いた振動解析により、例えば以下の（９）、（１０）に示されるように定式化される。

In addition, by performing vibration analysis of the drive shaft assembly using the CAE model created including the above-described steps [1] to [3], the drive shaft assembly moves from the input side to the axial direction or the axial direction. It is possible to formulate a load that acts on the output side of the drive shaft assembly when the vibration of is input. As described above, the load acting on the output side of the drive shaft assembly includes the axial straight direction load Fth acting on the output side constant velocity joint 3 in the axial direction (the axial direction of the shaft portion 10), and the equivalent speed joint. 3, a folding direction load Fbe acting in the folding direction of the drive shaft 1 is given. The axial straight direction load Fth and the bending direction load Fbe are formulated by, for example, the following (9) and (10) by vibration analysis using the CAE model.

以上詳述した本実施形態によれば、以下に示す効果が得られるようになる。

According to the embodiment described in detail above, the following effects can be obtained.

  (1) As a CAE model for vibration analysis of the drive shaft assembly, torque acting in the rotational direction at an arbitrary position on the drive shaft 1 and torque acting in the bending angle direction at the above position are modeled. Further, in these torque models, the spring constants kθ and kα in the rotational direction and the bending angle direction of the drive shaft 1 in the constant velocity joints 2 and 3 modeled as spring elements, and the constant velocity joints 2 and 3, respectively. Damping coefficients cθ and cα with respect to the rotation direction and the bending angle direction of the drive shaft 1 are used. The spring constants kθ and kα and the damping coefficients cθ and cα are obtained based on the test results of the vibration test performed with the drive shaft assembly rotated around the axis. For this reason, the spring constants kθ and kα and the damping coefficients cθ and cα used in the torque model correspond to the rotation of the drive shaft assembly, and the CAE model created using the model also rotates the drive shaft assembly. It will correspond to time. As described above, the CAE model for vibration analysis of the drive shaft assembly in a state of rotating around the axis can be created, and the CAE model can be created easily and with high accuracy.

  (2) The spring constants kθ and kα and the damping coefficients cθ and cα of the constant velocity joints 2 and 3 modeled as spring elements are obtained by performing a rotation order analysis on the result of the excitation test and determining the vibration of the entire drive shaft assembly. The transfer characteristic can be obtained and calculated from the transfer characteristic and the design specification value of the drive shaft assembly. As a result, the spring constants kθ and kα and the damping coefficients cθ and cα can be calculated with high accuracy.

  DESCRIPTION OF SYMBOLS 1 ... Drive shaft, 2 ... Constant velocity joint, 3 ... Constant velocity joint, 4 ... Shaft part, 5 ... Outer race, 6 ... Tri-board, 7 ... Roller shaft, 8 ... Roller, 9 ... Groove, 10 ... Shaft part, 11 ... outer race, 12 ... inner race, 13 ... retaining ring, 14 ... ball, 15 ... motor, 16 ... motor, 17 ... tachometer, 18 ... 6-component force meter.

Claims (2)

In creating a CAE model for vibration analysis of a drive shaft assembly having constant velocity joints on the input side and output side of the drive shaft, the constant velocity joint is modeled as a spring element including the elastic change of the drive shaft, In the drive shaft assembly model creation method for creating the CAE model using the constant velocity joint model,
An excitation test for applying axial vibration and axial vibration to the input shaft of the drive shaft assembly in a state where the drive shaft assembly is rotated around the axis is performed. Obtain the spring constant and damping coefficient of the constant velocity joint as the spring element from the design specification values,
Arbitrary positions on the drive shaft are based on the constant velocity joint on the input side of the drive shaft as the origin, and the rotation angle of the drive shaft assembly in the input rotation direction and the bending angle of the drive shaft with respect to the constant velocity joint are offset. And defining the rotation angle and the bending angle by defining a spherical coordinate having a radius from the origin to an arbitrary position on the drive shaft,
As the CAE model, the torque acting in the rotation direction of the shaft at an arbitrary position on the drive shaft is the torque depending on the rotation angle, the angular velocity thereof, and the spring constant and the damping coefficient of the spring element in the rotation direction. And the torque acting in the bending angle direction of the drive shaft with respect to the constant velocity joint at the arbitrary position as the bending angle, the angular velocity thereof, and the spring constant and damping in the bending angle direction of the spring element. A drive shaft assembly model creation method characterized by being modeled as a torque dependent coefficient. When the vibration test is performed, a rotational order analysis is performed on the result of the test to obtain a vibration transmission characteristic of the entire drive shaft assembly, and the spring is determined from the transmission characteristic and a design specification value of the drive shaft assembly. The drive shaft assembly model creation method according to claim 1, wherein a spring constant and a damping coefficient of a constant velocity joint as an element are obtained.

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