JP2009026128A - Method for creating model of drive shaft assy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for creating a model of a drive shaft assy, which can easily and highly accurately create a CAE model for vibration analysis. <P>SOLUTION: Input side and output side constant velocity joints 11, 12 are modeled as spring elements (a translation spring 13 and rotational springs 14, 15) including also an elastic change of a drive shaft 10 to create the CAE model for vibration analysis of the drive shaft assy which is applied to a vehicle. Consequently, the drive shaft 10 can be simplified by regarding it as a complete rigid body and the CAE model for vibration analysis can be easily and highly accurately created. <P>COPYRIGHT: (C)2009,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.
JP-A-9-189601

  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.

  The present invention has been made in view of such a situation, and the problem to be solved is to provide a drive shaft assembly model creation method capable of easily and accurately creating a CAE model for vibration analysis. There is to do.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is a method of creating a CAE model for vibration analysis of a drive shaft assembly having a constant velocity joint, wherein the constant velocity joint is modeled as a spring element including an elastic change of the drive shaft. The gist is to make it.

  In the above configuration, the constant velocity joint is modeled by defining it as a spring element including the elastic change of the drive shaft. In this case, the drive shaft itself can be regarded as a complete 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.

  It is to be noted that the drive shaft assembly is most simply modeled as described in claim 2 in which one of the two constant velocity joints installed on the drive shaft assembly is connected to a translation spring in the axial direction of the drive shaft. Modeling can be performed with a rotary spring around the axial direction of the drive shaft, and the other can be modeled with a rotary spring around the axial direction of the drive shaft.

  Further, the spring constant of the spring element in the model can be easily calculated from the result of the vibration test using the actual drive shaft assembly. For example, when modeling in the aspect of claim 2, as described in claim 4, an excitation test using an actual drive shaft assembly is performed to determine the axial direction of the entire drive shaft assembly, Then, the spring constant in the axial direction can be calculated, and the spring constants of the translation spring and the rotary spring can be easily obtained from the result and the design specification values of the drive shaft assembly. In addition, as described in claim 5, by using the length, weight and moment of inertia of the drive shaft and the cantilever rigidity of the two constant velocity joints as design specification values of the drive shaft assembly, the spring The constant can be calculated with high accuracy.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment embodying a method for creating a drive shaft assembly model according to the present invention will be described in detail with reference to FIGS. In this embodiment, the constant velocity joint is modeled as a spring element including the elastic change of the drive shaft, and the model is simplified, so that the CAE model for vibration analysis can be created easily and with high accuracy. I have to.

  FIG. 1 shows a CAE model for vibration analysis of a drive shaft assembly created by the model creation method of this embodiment. The drive shaft assembly that is the object of modeling here has an input-side constant velocity joint 11 at the engine-side end of the drive shaft 10 and an output-side constant-velocity joint 12 at the suspension-side end. It has an installed configuration. As shown in the figure, in this model, the input side constant velocity joint 11 installed at the engine side end of the drive shaft 10 is connected to the axial translational spring 13 of the drive shaft 10 and the axis of the drive shaft 10. It is regarded as a rotating spring 14 around the direction. The constant velocity joint 12 on the output side installed at the suspension side end of the drive shaft 10 is regarded as a rotation spring 15 around the axis of the drive shaft 10. Further, in this model, the elastic change of the drive shaft 10 itself is considered to be included in each of the spring elements (translation spring 13 and rotation springs 14 and 15). That is, in this model, the drive shaft 10 is regarded as a complete rigid body.

  Now, in order to use such a CAE model for vibration analysis, it is necessary to obtain the spring constant of each spring element. In the model creation method of this embodiment, those spring constants are calculated based on the result of the vibration test using the actual machine of the drive shaft assembly. More specifically, a vibration test is performed to calculate the spring constant K * in the axial direction and the axial direction of the drive shaft assembly. From the calculation results and design specification values of the drive shaft assembly, The spring constant is calculated.

  FIG. 2 shows an embodiment of the vibration test using an actual drive shaft assembly. This vibration test is performed while applying a twisting torque from the engine side end of the drive shaft assembly in a state where the shaft bending angle at each of the constant velocity joints 11 and 12 is set to a predetermined test angle θ. Then, the vibration in the axial direction or the axial direction is input from the engine side end (vibration unit) of the drive shaft assembly, and the vibration transmission mode at the suspension side end (response unit) of the drive shaft assembly is divided into 6 minutes. An excitation test is performed by measuring with the force meter 20.

  FIG. 3 shows an example of measurement results of vibration transfer characteristics in such an excitation test. In the figure, the relationship between the spring constant K * of the drive shaft assembly and the torque in each of the axial direction and the direction perpendicular to the axis determined by the vibration test is shown. The spring constant of the translation spring 13 in the above model can be obtained from the relationship between the spring constant K * of the drive shaft assembly in the axial direction and the torque.

  On the other hand, the spring constant K of the rotary springs 14 and 15 in the above model 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１０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１１，１２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。回転ばね１４，１５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 10 and the cantilever k1 and k2 of the constant velocity joints 11 and 12 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 rotary springs 14 and 15 can be obtained by solving the above equations (1) and (2) for the spring constant K.

  As described above, the CAE model for vibration analysis of the drive shaft assembly in which the input-side and output-side constant velocity joints 11 and 12 are modeled as spring elements including the translation spring 13 and the rotary springs 14 and 15 can be created. The CAE model created in this way is used for evaluation of the state of occurrence of vibration and noise of the vehicle together with the CAE model of other vehicle components such as the engine and the suspension.

  In the present embodiment described above, the input-side and output-side constant velocity joints 11 and 12 are modeled as spring elements including the elastic change of the drive shaft 10 to create a CAE model for vibration analysis of the drive shaft assembly. ing. More specifically, the constant velocity joint 11 on the input side is modeled by a translation spring 13 in the axial direction of the drive shaft 10 and a rotary spring 14 around the axial direction of the drive shaft 10. The constant velocity joint 12 on the output side is modeled by the rotary spring 15. Then, a vibration test using an actual machine is performed to calculate the spring constant K * in the axial direction and the axial direction of the entire drive shaft assembly, and the result and the drive shaft 10 which is a design specification value of the drive shaft assembly. The spring constants of the translation spring 13 and the rotary springs 14 and 15 are obtained from the length L, the weight M, the moment of inertia J, and the cantilever k1 and k2 of the constant velocity joints 11 and 12 on the input side and the output side. I am doing so. In this case, the drive shaft 10 itself can be regarded as a completely rigid body, and the model is simplified. Therefore, according to the drive shaft assembly model creation method of the present embodiment, the vibration analysis CAE model can be created easily and with high accuracy.

In addition, the said embodiment can also be changed and implemented as follows.
In the above embodiment, the input side constant velocity joint 11 is modeled as a translation spring 13 and a rotation spring 14, and the output side constant velocity joint 12 is modeled as a rotation spring 15. It is also possible to create a model so that the translation spring element is provided on the constant velocity joint 12 side on the output side. That is, the input side constant velocity joint 11 can be modeled as a rotation spring, and the output side constant velocity joint 12 can be modeled as a translation spring and a rotation spring 15. A model may be created so that both the input side and output side constant velocity joints 11 and 12 have translation spring elements.

  The calculation of the spring constant of each spring element in the CAE model may be performed in a mode other than that shown in the above embodiment. For example, if there is an appropriate relational expression other than the above expressions (1) and (2), the spring constant of each spring element may be calculated using the relational expression. In any case, if the constant velocity joints 11 and 12 are modeled as spring elements including the elastic change of the drive shaft 10 to create a CAE model for vibration analysis of the drive shaft assembly, the drive shaft 10 is regarded as a completely rigid body. Therefore, it becomes possible to simplify the vibration analysis CAE model with high accuracy.

The schematic diagram showing the composition of the CAE model for vibration analysis of the drive shaft assembly created by the model creation method about one embodiment of the present invention. The schematic diagram which shows the aspect of the vibration test performed in order to calculate the spring constant of the spring element about the CAE model produced in the embodiment. The graph which shows an example of the measurement result of the transmission characteristic of the drive shaft assembly by the same vibration test.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Drive shaft, 11 ... Input side constant velocity joint, 12 ... Output side constant velocity joint, 13 ... Translational spring (input side constant velocity joint), 14 ... Rotation spring (input side constant velocity joint), 15 ... rotary spring (constant joint on the output side), 20 ... 6 component force meter.

Claims (5)

A method of creating a CAE model for vibration analysis of a drive shaft assembly having a constant velocity joint,
A method for creating a model of a drive shaft assembly, wherein the constant velocity joint is modeled as a spring element including an elastic change of the drive shaft. One of the two front and rear constant velocity joints installed on the drive shaft is modeled by a translation spring in the axial direction of the drive shaft and a rotary spring around the axis of the drive shaft, and the other is modeled on the shaft. The method for creating a model of a drive shaft assembly according to claim 1, wherein modeling is performed with a rotary spring around a straight direction. The method for creating a drive shaft assembly model according to claim 1 or 2, wherein a spring constant of the spring element is calculated from a result of an excitation test using an actual drive shaft assembly. Perform an excitation test using the actual drive shaft assembly to calculate the axial direction of the entire drive shaft assembly and the spring constant in the direction perpendicular to the axis, and the calculation results and design specification values of the drive shaft assembly The drive shaft assembly model creation method according to claim 2, wherein each spring constant of the translation spring and the rotary spring is obtained from the model. The drive shaft assembly model creation method according to claim 4, wherein the design specification value includes a length, a weight, and a moment of inertia of the drive shaft and a cantilever rigidity of the two constant velocity joints.

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