JP3473645B2 - Mechanical parts accuracy evaluation device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a mechanical system component accuracy evaluation apparatus, and more particularly, a computer, which obtains an influence on a behavior change due to a dimensional tolerance of a component or an assembly tolerance when analyzing the behavior of a component constituting a mechanism. The present invention relates to a mechanical system component accuracy evaluation device suitable for use in a CAD drawing creation system that creates drawings.

[0002]

2. Description of the Related Art CAD drawing systems for creating drawings using a computer are already widely known and widely used, and in particular, a designer and a computer proceed with processing interactively via a display or the like. Iku interactive CA
The D drawing creation system has become the mainstream and is widely used for designing mechanical structures (mechanisms).

On the other hand, when designing such a mechanism, a mechanism analysis for analyzing the behavior of each part constituting the mechanism is performed. Conventionally, the following method is known for this mechanism analysis. Has been. (1) In the conventional mechanism analysis of a system (play system) when there is play in the joint part, the following modeling is performed, and a complex analysis is performed while considering the modeling each time the mechanical system is given. Was there. (A) A constant contact model in which the pin and the pin hole are always in contact with each other. (B) A model that considers the collision between the pin and the pin hole. (C) A flexible kinematic pair model in which a kinematic pair with play is regarded as a 5-degree-of-freedom vibration system (in the case of 4-bar linkage).

In particular, in the above model (a), assuming that there are gaps in all the joints, as in, for example, the Japan Society of Mechanical Engineers, Vol. 43, No. 371, a link equal to the radius of this gap is used. We are using it to analyze the mechanism. Moreover, in this model, the 4-bar linkage is used as the target, however, the actual general machine is a complicated mechanical system that constitutes a plurality of closed loops, and is also applied to these in general. There is a need for a system that is capable and that can be analyzed in an easy to understand manner.

(2) On the other hand, it is already known that the mechanism of the rattling system is not analyzed but the change in the characteristic value due to the length of the link is calculated to calculate the assembly accuracy ( For example, Journal of Mechanical Design MARCH 199
1, Vol.113 / 9). However, although such an analysis method is effective in obtaining the joint motion range, it does not provide a satisfactory solution to dynamic characteristic changes.

[0006]

As described above, according to the above-mentioned conventional technique, a CAD drawing creating system for creating a drawing by using a computer, particularly, an interactive CAD drawing creating system is used for designing. While performing a mechanism analysis that analyzes the behavior of each component that makes up the existing mechanism,
There has been a strong demand for a method for evaluating the accuracy of mechanical system parts, which is capable of determining the influence on the behavior change due to the dimensional tolerance and the assembly tolerance of the mechanical parts.

However, in the above prior art (1),
It is necessary to calculate the size of the play (play) of the connection part based on the tolerance of the mechanical parts, and to model it appropriately and analyze the behavior of the mechanical system. Therefore, it is still done by the designer. It cannot be said that the level has been reached. In addition, this method requires an analysis of 5 degrees of freedom even in the case of the 4-bar linkage, which requires a very complicated analysis. In this case, a normal designer uses a CAD drawing system to draw a drawing. There is a problem that it is not suitable for use to evaluate the shape of mechanical parts while easily performing analysis in the process of creating, and execution of such complicated analysis is not practical.

Further, in the above-mentioned prior art (2), the influence of the change in the length of the link on the operating range of the link mechanism is displayed so that it can be seen at a glance. However, the operation of this link mechanism There is a problem that it is difficult to understand in order to obtain the influence on the behavior change due to the dimensional tolerance and the assembly tolerance of the mechanical parts by the method based on the range unless the operator is accustomed to the mechanical study.

That is, the above-mentioned prior arts (1) and (2) are for performing dynamic analysis of the mechanism, and the dimensional tolerance of the mechanical component when designing the mechanical component by the CAD drawing system is performed as it is. It is difficult to actually use it as a method for evaluating the accuracy of mechanical system parts, which seeks the influence on the behavior change due to the assembly tolerance. In the actual design stage, this is information that the designer wants to know as soon as possible how much the operating range of the component deviates from the ideal state due to the play or gap (hereinafter simply referred to as “backlash”) of the joint. ,
That is, in practice, it is easier for the designer to directly evaluate the design itself.

Therefore, in the present invention, in view of the above-mentioned problems in the prior art, that is, the behavior that can be executed by a simple input / output method due to the dimensional tolerance and the assembly tolerance of the mechanical parts designed by the designer. It is an object of the present invention to provide a mechanical system component accuracy evaluation device capable of determining the influence on the.

Based on the shape data of the parts created by using the CAD drawing creation device and the size of the backlash at the fitting portion between the parts, the backlash is replaced with an equivalent link model or the like to perform a mechanism analysis to determine the backlash operating characteristics. Impact on CAD
An object of the present invention is to provide a device which is displayed by the above-mentioned parts diagram and graph, and which is capable of evaluating mechanical system assembly tolerances rich in man-machine interface.

[0012]

SUMMARY OF THE INVENTION The present invention is a mechanical part accuracy evaluation apparatus used in a CAD drawing creation system for creating a drawing using a computer.
In order to input the dimensional tolerance or the assembly tolerance of the mechanical component shape displayed in the CAD diagram in the one in which the mechanical analysis model is generated based on the CAD diagram of the mechanical system component created by the drawing creation system and the mechanical analysis is performed. Tolerance data input means, mechanism analysis model automatic generation means for automatically generating the mechanism analysis model based on the tolerance data input by the tolerance data input means, and the mechanism system based on the tolerance of the mechanical parts on the CAD diagram. Mechanism analysis execution means for analyzing changes in the behavior of parts using this mechanism analysis model,
Correlating the behavior change of the mechanical system component analyzed by the mechanical analysis executing means with time or the posture of the mechanical component,
Display means for displaying on the screen of the CAD drawing creation system display section is provided, and the mechanism analysis model automatic generation means generates a backlash equivalent link model with a gap calculated based on the input tolerance. Disclosed is a mechanical system component accuracy evaluation apparatus characterized by being configured as follows.

Furthermore, the present invention is a mechanical system component accuracy evaluation apparatus used in a CAD diagram creating system for creating a drawing by using a computer, which is a CAD diagram of a mechanical system part created by a CAD diagram creating system. In the one that performs the mechanism analysis by generating the mechanism analysis model based on
Tolerance data input means for inputting the dimensional tolerance or assembly tolerance of the mechanical part shape displayed in the CAD drawing, and a mechanical analysis model for automatically generating the mechanical analysis model from the tolerance data input by the tolerance data input means. Automatic generation means, mechanism analysis execution means for analyzing behavior changes of the mechanical system parts due to the tolerances of the mechanical parts on the CAD diagram by using this mechanical analysis model, and the mechanical analysis execution means analyzed by the mechanical analysis execution means. The behavior change of the mechanical system part is made to correspond to the time or the posture of the mechanical part, and the CA
And a display means for displaying on the screen of the D diagram creating system display unit, and the mechanism analysis model automatic generation means,
A link model is generated from the gap calculated based on the input tolerance, and the mechanism analysis execution means further performs dynamic analysis based on at least one of the external force and the moment of inertia or the mass that are further input. Disclosed is a mechanical system component accuracy evaluation device having the above-described configuration.

Furthermore, the present invention is a mechanical part accuracy evaluation apparatus used in a CAD drawing creation system for creating a drawing by using a computer, which is a CAD drawing of a mechanical part created by the CAD drawing creation system. In the one that performs the mechanism analysis by generating the mechanism analysis model based on
Tolerance data input means for inputting the dimensional tolerance or assembly tolerance of the mechanical part shape displayed in the CAD drawing, and a mechanical analysis model for automatically generating the mechanical analysis model from the tolerance data input by the tolerance data input means. Automatic generation means, mechanism analysis execution means for analyzing behavior changes of the mechanical system parts due to the tolerances of the mechanical parts on the CAD diagram by using this mechanical analysis model, and the mechanical analysis execution means analyzed by the mechanical analysis execution means. The behavior change of the mechanical system part is made to correspond to the time or the posture of the mechanical part, and the CA
And a display means for displaying on the screen of the D diagram creating system display unit, and the mechanism analysis model automatic generation means,
Disclosed is a mechanical system component accuracy evaluation device, which is configured to generate a yarn model corresponding to a gap calculated based on an input tolerance.

[0015]

According to the mechanism-system component accuracy evaluation apparatus proposed by the present invention, a designer who designs a mechanism by this system automatically generates the mechanism analysis model provided in the CAD drawing creation system by the present invention. By using the mechanism analysis model generation unit, it is possible to easily evaluate the influence of play in the joint portion of the mechanical parts to be designed. That is, according to the mechanical system component accuracy evaluation apparatus used in the system proposed by the present invention, the analysis of the mechanical system constituted by CAD drawing creation input is performed by inputting the tolerance by an operator such as a designer. It is possible to analyze changes in dynamic reaction force, etc., and it is possible to calculate changes in motion trajectory with good responsiveness. Moreover, by using such a CAD drawing system,
Based on the created part shape data and the size of the backlash at the fitting part between parts, replace the backlash with an equivalent link model and perform a mechanism analysis. Regarding the influence on the backlash operating characteristics, use the part diagram and graph on CAD. By displaying, it becomes possible to evaluate the tolerance of mechanical system assembly tolerances rich in man-machine interface.

More specifically, based on an embodiment of the present invention described in detail below, more specifically, a shape drawing (CAD drawing) displayed on the screen of a display device which is a terminal device of a CAD drawing creating system will be described. ) Above, if you input the tolerance (play) of the fitting part of any mechanical part, the play equivalent link model according to the size of the gap calculated based on this is automatically generated and this model is included. A mechanism analysis model is automatically generated and a mechanism analysis is executed. The result of this analysis is
Regarding the behavioral characteristics of the mechanical system (changes in position, velocity, acceleration, reaction force at each joint, and changes in the motion locus of mechanical parts), a comparison between when there is zero backlash and the degree of influence of the backlash at each joint It becomes possible to output using a graph showing comparison and an operation locus diagram corresponding to various variations.

[0017]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. First, FIG. 1 shows a schematic configuration of a CAD drawing creation system using a mechanical system part accuracy evaluation method according to an embodiment of the present invention. This CAD drawing creation system includes a calculation unit 11 and a CAD drawing creation. A central processing unit 10 including a unit 12, a memory device (not shown) and the like, and a central processing unit 10 connected to the central processing unit for inputting for drawing, such as a keyboard and a mouse. An interactive input / output device 20 including an input device, a display device for displaying an input drawing or a display for displaying a dialogue, and an output device such as a printer, and an external storage device 30.
It consists of

The internal configuration of the central processing unit 10 will be described in detail below.
In addition to the D diagram creation unit 12, the link mechanism analysis model generation unit 1
3 and a rattling mechanism analysis execution unit 14 including a mechanism analysis control unit 141 and a mechanism analysis execution program unit 142 therein. In addition, the external storage device 30 includes an analysis file 31 and a graphic data file 32.

When designing some mechanism using the CAD drawing creation system having the above-mentioned configuration, the designer must
A mechanical system part diagram, which is each part of the mechanism, is input using an input device such as a keyboard and a mouse of the interactive input / output device 20, and at the same time, a mechanical system part diagram is input on the display device. While displaying, each design work will be performed.

According to the present invention, so-called mechanical system component precision evaluation is performed, in which the influence on the behavior change due to the dimensional tolerance and assembly tolerance of the mechanical component when designing the mechanical component by the CAD drawing system is obtained. In this case, first, the mechanical parts diagram already input by the designer is
The CAD diagram creation unit 12 of the central processing unit 10 displays it on the interactive input / output unit 20, for example, on the display device. Here, the designer who is the operator uses the input device such as the keyboard and mouse of the interactive input / output unit 20 while displaying the C displayed on the display device.
While instructing the parts on the AD screen, the respective tolerances of the instructed parts are input. After that, for example, the size of the gap between the fitting parts is obtained by the CAD creating part 12 from the fitting tolerance of the input engaging parts. Then, in the link mechanism analysis model generation unit 13, the link model of the gap (the backlash equivalent link model) is made, and further, the link mechanism analysis modeling of the link mechanism component is automatically generated here.

Thereafter, based on the generated data and the analysis input data such as the analysis conditions already input by the interactive input / output unit 2, the rattling mechanism analysis execution unit 14 of the central processing unit 10 described above. The analysis is executed in. The rattling system mechanism analysis execution unit 14 includes a mechanism analysis control unit 141 and a mechanism analysis execution unit 142. The former mechanism analysis control unit 141 can separately store, as a method of storing analyzed data, a calculation result when the gap is 0 and a calculation result when the gap is given an arbitrary size. Thus, a data management function is provided. Also,
The mechanism analysis control unit 141 calculates the minimum value or the maximum value (variation value) from the analysis result, and further,
Processing such as sensitivity analysis is performed from these fluctuation values. Further, the latter mechanism analysis execution unit 142 includes an analysis program and executes the mechanism analysis described in detail below. In addition, the analysis result performed here is the analysis file 3 once.
The analysis result is displayed in the CAD drawing creating unit 12. That is, a desired graph or motion locus diagram is displayed on the CAD screen based on the identification flag input by the data input unit using the CAD screen.

Next, the flow chart of FIG. 2 attached heretofore shows the method for evaluating the accuracy of mechanical system parts executed in the above-described embodiment, that is, the method for obtaining the influence on the behavior change due to the dimensional and assembly tolerances of the mechanical parts. It will be explained with reference to FIG. In the description of this flow chart, a mechanism analysis model of a four-bar linkage mechanism as shown in the attached FIGS. 3 to 5 is used.

First, in step S1, while inputting the mechanical system component diagram displayed in the CAD diagram as shown in FIG. 3A, the coupling condition of the mechanical component and the fitting tolerance between the engaging components are input. . In the following description, the mechanism is a mechanism composed of a single loop, the link is indicated by the symbol "L", and the joint is indicated by the symbol "J".

Next, in step S2, the size of the gap is calculated based on the tolerance given in the above step, and the link mechanism analysis model generator (reference numeral 13 in FIG. 1) displays the size in FIG. 3 (b). The mechanism analysis model shape data as shown is generated. In the example shown in FIG. 3B, the joint J3
Only when the tolerance is given. The connected link L3 is rotated so that the length is equal to the size of the gap, and the link L5 corresponding to the gap is generated. Further, when all the joints have tolerances, the model shown in FIG. Basically, the link to be connected is rotated, but when there is a gap between the joints at both ends of the link, a quadrangle consisting of both clearance links and two equal-length links is formed. The above shows the analytical model in the case of a mechanism consisting of all rotary joints (joints that freely connect two links to rotate freely).

Next, a method for generating a clearance link in the case of a mechanism having a sliding joint (a joint that joins two links so as to slide relative to each other) will be described. FIG. 3D shows a mechanical system component including the spring SP,
This spring SP can be modeled by two links connected by a sliding joint J2, as shown in FIG. 3 (e).
When the joint J3 has a backlash, the two links are rotated about the joint J1 so that the two links are aligned with each other to form a clearance link L5.

Further, a rattling system link model generation method of a mechanism forming a plurality of closed loops will be described here.
As shown in FIG. 4A, when the joint (joint J3 in this example) for inputting backlash is included in only one loop, the same model is used according to the link modeling method for the single loop described above. You can generate the model shown on the right. However, as shown in FIG. 4B, when a play is input to a common point (here, joint J4) of a plurality of loops, there are two links for one part (see FIG. 4).
In (b), since the links L4 and L8 correspond to the part A), it is not possible to make a clearance link by itself. Therefore, the backlash equivalent link model is generated by the following method.

That is, in the mechanism system shown in FIG. 4, since the link L4 and the link L8 operate integrally, when considering the play of the joint J4, the link L4 is joined to the joint J3 in order to newly create the link L9. Rotate around. Along with this, the positions of the joint J6 and the joint J7 change. Therefore, in order to obtain this change amount, the posture analysis input data is automatically generated and the mechanism analysis is performed. As the posture analysis input data, first, joints J1 and J4 are used to change the angle. Further, since the joint 4 is loose, it is rotated once. Then, the change of each joint is obtained.

Next, in step S3, the rotatable range of the equivalent link of the backlash is calculated. FIG. 5A shows a state in which the two links L3 and L4 are coupled via the clearance link L5. Fix joint J2 and link L
It is assumed that 3, L4 and L5 move. Clearance link L
When 5 is rotated about the joint J2, the joint J4 at the end point of the link L4 is a circle 2 whose radius is the length R of the fixed link L1 'in order to establish the four-bar linkage.
A circle 202 centered on the joint J3 and having a radius of the length r of the link L4 is required to be on the circumference of 01.
However, it is necessary to have an intersection with the above-mentioned circle 201. At the limit point of the position of the joint J3, the two circles 201 and 2 are
02 will come into contact. Therefore, as shown in FIG. 5B, a circle 20 formed by rotating the clearance link L5.
The intersection of 3 and the circle 204 of radius (R-r) is the limit point, and the range from these limit points a1 to a2 is the operating range (shown by the diagonal lines).

Further, in step S4, a mechanism analysis is executed based on the above. That is, the maximum value and the minimum value of the position / reaction force of each joint portion due to the gaps of all joint portions are calculated, and the sensitivity of the size of the gap of each joint portion to the position / reaction force of each joint portion is analyzed. In the case of trajectory analysis, the maximum or minimum value of each performance value is obtained while changing the link operable range of all rattles at fixed intervals in a posture in which the angle of the driving point is arbitrarily changed. Next, in step S5, the analysis result is written in a file. At this time,
At the same time, analysis is performed when the backlash is 0, and this is also written (output) to the file.

In step S6, a graph display (relationship between rotation angle and position), an example of which is shown in FIG. 6 (a), for example, by the input identification flag using the above analysis result.
Is displayed on the display device of the interactive input / output unit 20 of the CAD drawing system (comparison display). On the other hand, in step S7, using the above analysis results, the input identification flag is used to display a motion locus corresponding to time as shown in an example in FIG. 6B. In this trajectory display, a so-called management unit is provided so that the trajectory can be input to the analysis result file in correspondence with the variation state, and thereby a desired trajectory can be displayed by the identification flag (so-called trajectory display selection function). . This is because, if the operator aims to check the interference of parts, by selecting the maximum value in the direction in which the part exists and displaying the locus, for example, when there is a part that is likely to interfere in the y direction, By designating the graphic 103 displaying the “maximum value in the y direction” from the selection buttons on the display screen as shown in 7, the link posture in which the coordinate value in the y direction of each joint becomes maximum in each posture. The loci are displayed side by side. Further, here, in order to check the interference between the parts in more detail, it is necessary to examine the contour lines of the parts. Therefore, it is possible to provide an input means for making it possible to select a part to be checked in advance before analysis, or a point or a line element on the part.

On the other hand, based on the above analysis results, it is possible to further display a graph about the influence of the size of the gap of an arbitrary joint on various performance values (position, velocity, acceleration, reaction force, etc.). You can also do it. In this case, the data table on the vertical axis of the graph has a format capable of storing a plurality of data so that the sensitivity coefficients of the sizes of the gaps of the joints can be compared. Also, the maximum value and the minimum value of these data are obtained and the scale of the vertical axis is created.
Through the above processing, the operator, for example, the designer of the mechanical component, easily determines the size of the tolerance of the design mechanism on the CAD diagram while checking various factors such as interference and strength of members. It becomes possible to do.

Next, another embodiment of the present invention will be described with reference to the attached FIG. In addition, in the other embodiment, it is possible to perform dynamic analysis of the mechanism to be designed, as compared with the embodiment in which the mechanism analysis described above is performed. That is, it is a process according to a modeling method for generating a virtual link for a gap in the play.

The operation of the other embodiment will be described with reference to the flow chart shown in FIG. 8 attached. First, in step S11, the mechanical system parts diagram displayed on the CAD drawing is designated, as in the above embodiment. Meanwhile, the coupling condition of the mechanical parts and the fitting tolerance between the engaging parts are input. Next, in step S12, the size of the gap is calculated based on the tolerance given in the above step, and the link mechanism analysis model generation unit (reference numeral 13 in FIG. 1) analyzes the link mechanism as described above. Model shape data is generated, and further, in step S13, a backlash equivalent link model is created.

Then, in step S14, an external force, a moment of inertia, a mass and the like for dynamic analysis are input. At this time, the rotation angle of the play can be calculated by solving the equation of motion in the case of dynamic analysis. However, if the operating range of the backlash equivalent link is exceeded, the solution will diverge, so in this case as well, it is necessary to calculate the rotatable range of the backlash equivalent link as in step 15. Then step 16
In step 17, the dynamic characteristic analysis of the mechanical system to be designed based on the created model and the position / reaction force of each connecting portion are obtained, and in step 17, the analysis result is written to a file, which is the same as in the above-mentioned embodiment. .

It is also possible to provide a calculation means for performing a calculation while checking the operating range at each time step and, if the operating range is exceeded, fixing the movement of the backlash. Furthermore, the display method of the analysis result is
Similar to the above embodiment, for example, the procedure shown in the flowchart of FIG. 2 is followed.

Next, still another embodiment of the present invention will be described with reference to the attached FIGS. 9 to 14. In this further embodiment, as another modeling method different from the above, the portion corresponding to the backlash is replaced with a thread-shaped model having a constant length and free from bending deformation. In this model, however, the method using the coordinate transformation matrix based on the fact that the links form a closed loop cannot be used. Therefore, the equation of motion is calculated independently for each link. It should be noted that the reaction force between the links works only when the yarn is pulled, and this is because, as will be described later, internal forces act on each other when the shaft is in contact with the bearing surface.

Another embodiment using such a thread-like model will be described. As described above, one of the purposes for obtaining the influence of the size of the gap is to know the change in the operating range of the parts. is there. In the case of still another embodiment using this thread-shaped model, it is possible to obtain simply without resorting to the complicated analysis as in the above-mentioned embodiment, which may improve the operability.

First, the principle of this thread model is shown in FIG.
A description will be given using (a) and (b). When tensile force 901 is applied to the point D of the mechanism shown in FIG. 9A in the direction of the arrow, the link and the rattling equivalent model are aligned in a straight line because the portion corresponding to the gap is the thread. Therefore, as shown in FIG. 9B, the position of the point D can be calculated as the apex of a triangle whose both sides are line segments obtained by adding the length of the gap to one side or both sides of the link. In this case, since the thread model is included in the joint between the links, the conventional mechanism analysis method cannot be used. For this reason, for example, the direction of force is input interactively based on the model in the figure. Thus, it is possible to obtain the maximum displacement of any joint.

Further, as shown in FIG. 10A, when one component 1001 has three or more joints (in this case, the joints J3, J7, and J4), a force is exerted by the thread connected to the component. The position of these joints is calculated by finding the balanced position. As shown in FIG. 10B, a plurality of external forces 1002, 1003, 1004.
In addition, when the respective action points are different (points E, F, and G), the link and the thread are not always aligned with each other. In this case, the force balance is calculated and the position of the link and the yarn is calculated.

The calculation procedure based on this thread model is shown in FIG.
It will be described based on the flowchart shown in FIG. The method of displaying the analysis result follows the procedure in the embodiment shown in FIG. 2, as in the other embodiment of the dynamic analysis. First, in step S21, similar to the above embodiment,
While instructing the mechanical system component diagram displayed on the CAD diagram, the coupling condition of the mechanical component and the fitting tolerance between the engaging components are input. Next, in step S22, the size of the gap is calculated based on the tolerance given in the above step, and the link mechanism analysis model generation unit (reference numeral 13 in FIG. 1) analyzes the link mechanism as described above. Generate model shape data,
Further, in step S23, a yarn model is generated, and in step 24, the magnitude of force and the point of action are input.

The feature of this other embodiment is that the direction of the force is input in the above step 24.
In this case, there is a limitation that the yarn does not stretch. This represents the condition for the shaft 120 to be in the bearing hole 121 of the bearing as shown in FIG.
The distance between the center c1 of the bearing hole 121 and the center c2 of the shaft 120 when the shaft 120 contacts the wall of the bearing hole 121 (that is, the limit at which the shaft 120 can move) corresponds to the yarn length. Further, in the model of FIG. 3 described above, the state where the shaft and the bearing are always in contact with each other is simulated, but in the case of this yarn model, it is possible to consider the case where the yarn loosens. That is, the state in which the shaft 120 floats in the bearing hole 121 is also included in this thread model.

Regarding the input of the size of the gap, not only the tolerance as the gap between the coupling portions but also
It may be a gap generated by friction during operation. In such a case, the gap does not always decrease uniformly due to friction, and therefore, as shown in FIG. 12A, the gap c is located at the position (in this case, it extends in the longitudinal direction at the center of the bearing hole 121). It is also possible to give as a function of the angle θ) from the reference line. Further, as shown in FIG. 12B, the bearing hole 121 has an elongated shape, and the shaft 120 has the bearing hole 1
When rotating and sliding within 21, it is also possible to represent the clearance c as a function of the position x in the sliding direction.

Furthermore, the wear function may be predicted from the operating state of the mechanism. Therefore, for example, as shown in FIG.
The depth of wear can be expressed by the angle α of the contact range where the shaft 130 contacts the bearing hole 131 and the number of collisions n. Alternatively, as shown in FIG. 14, the reaction force RF at the contact range (angle β) and the contact point between the shaft 140 and the bearing hole 141.
It is also possible to display the calculation result such as "" on the bearing.

[0044]

As is apparent from the above detailed description, according to the mechanical system component accuracy evaluation method and apparatus of the present invention and the CAD drawing creation system using the same, the design for designing mechanical system components is performed. The influence of the size of the gap due to the assembly tolerance of the joint portion of the mechanical component being designed or the manufacturing tolerance of the joint component on the behavior of the mechanical system is investigated by a person in charge of the design on the CAD diagram during the design process. You can easily check by just entering the manufacturing tolerance. for that reason,
Even a designer or operator who is unfamiliar with modeling to generate a mechanism analysis model for a gap can easily automatically generate and analyze a mechanism analysis model for a gap, which enables safe and reliable design work. become.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a CAD drawing creation system using an apparatus for executing a mechanical system component accuracy evaluation method according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure for executing a mechanical system component accuracy evaluation method of the CAD drawing creation system.

FIG. 3 is an explanatory diagram for explaining the principle of backlash equivalent link modeling adopted in the mechanical system component accuracy evaluation method.

FIG. 4 is a diagram showing an example of backlash equivalent link modeling in a link mechanism including a plurality of closed loops based on the backlash equivalent link modeling.

FIG. 5 is an explanatory diagram illustrating a principle for calculating an operation range of a backlash equivalent link model of the link mechanism including the plurality of closed loops.

FIG. 6 is a diagram illustrating an example of output of a result of evaluation of an influence of a gap in a link mechanism, which is a trajectory display and a graph display.

FIG. 7 is a diagram showing an example of a selection button for selecting a screen display range of a selected component when displaying the above trajectory map.

FIG. 8 is a flowchart showing a processing procedure for executing a mechanical system component accuracy evaluation method according to another embodiment of the present invention.

FIG. 9 is a principle explanatory diagram showing an example of a calculation model and a direction of an external force applied to the calculation model when a thread-like model is applied to a gap between mechanical system parts.

FIG. 10 is a diagram showing an example of a case in which the above-described calculation model based on the thread-like model is applied to a mechanical system component constituted by a plurality of loops.

FIG. 11 is a flowchart showing a processing procedure for executing a mechanical system component accuracy evaluation method according to still another embodiment of the present invention.

FIG. 12 is a conceptual diagram showing a relative positional relationship between the thread-shaped model and a shaft and a bearing hole in an actual link mechanism.

FIG. 13 is a conceptual diagram for inputting a function of a clearance due to wear contact between a shaft and a bearing hole of the link mechanism.

FIG. 14 is a conceptual diagram that outputs and displays a contact range between a shaft of the link mechanism and a bearing hole and a reaction force at each contact.

[Explanation of symbols]

10 Central processing unit 11 Operation part 12 CAD drawing department 13 Link mechanism analysis model generator 14 Rattling system mechanism analysis execution unit 141 Mechanism analysis control unit 142 Backlash Mechanism Analysis Execution Unit 20 Interactive input / output unit 30 external storage 31 Analysis file 32 graphic data files

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Iki Utsumi Ikigami, Haruoka-cho, Owariasahi-shi, Aichi Prefecture Ichigami, Office Systems Division, Office Systems Division, Hitachi, Ltd. (72) Mitsuru Kobayashi 1 Ikegami-cho, Haruoka-cho, Owariasahi, Aichi Prefecture Address, Hitachi, Ltd. Office Systems Division, Application Systems Division (72) Inventor, Yutaka Kako 1 Ikegami, Haruoka-cho, Owariasahi-shi, Aichi Prefecture Office Systems Division, Applications Systems Division (56) References Hiroshi Ozawa et al. Automatic generation of analytical model in mechanism analysis using CAD diagram, The Japan Society of Mechanical Engineers, Mechanics and Measurement Control Proceedings, Japan, The Japan Society of Mechanical Engineers, June 30, 1994, vol. A, p121-124, total number 940-26I Masamitsu Mochizuki et al. Knowledge expression language for cross analysis and its programming method, Journal of Information Processing Society of Japan, Japan, Information Processing Society of Japan, September 15, 1994 , Vol. 35, No. 9, p1922-1935 Philip Robinson, New movement in US design analysis tools: Human motion simulation and cross analysis are also possible, Nikkei CG, Japan, Nikkei BP, 1990 1 1st, 40th, p155-163, Takahashi et al., Kinetic analysis of contact parts by dynamics simulation, Journal of Japan Society for Precision Engineering, Japan, Japan Society for Precision Engineering, April 5, 1994, 712 (vol) .60 no.4), p530-534 (58) Fields investigated (Int.Cl. ⁷ , DB name) G06F 17/50

Claims (3)

(57) [Claims] 1. A mechanical system component accuracy evaluation device used in a CAD diagram creating system for creating a drawing using a computer, wherein the mechanism is based on a CAD diagram of the mechanical system part created by the CAD diagram creating system. In a system for generating an analysis model and performing a mechanism analysis, a tolerance data input means for inputting a dimensional tolerance or an assembly tolerance of a mechanical part shape displayed in the CAD diagram, and a tolerance input by the tolerance data input means. Mechanism analysis model automatic generation means for automatically generating the mechanism analysis model based on data, and mechanism analysis execution for analyzing the behavior change of the mechanism system component due to the tolerance of the mechanism component on the CAD diagram using the mechanism analysis model. Means and a change in the behavior of the mechanical system component analyzed by the mechanical analysis executing means with respect to time or the posture of the mechanical component. And a display unit for displaying the CAD diagram creation system on the screen of the CAD drawing creation system, and the mechanism analysis model automatic generation unit includes a backlash equivalent link model with a gap calculated based on the input tolerance. A mechanical system component accuracy evaluation device characterized in that it is configured to generate. 2. A mechanical part accuracy evaluation device used in a CAD drawing creation system for creating a drawing using a computer, wherein the mechanism is based on a CAD drawing of the mechanical part created by the CAD drawing creation system. In a system for generating an analysis model and performing a mechanism analysis, a tolerance data input means for inputting a dimensional tolerance or an assembly tolerance of a mechanical part shape displayed in the CAD diagram, and a tolerance input by the tolerance data input means. Mechanism analysis model automatic generation means for automatically generating the mechanism analysis model based on data, and mechanism analysis execution for analyzing the behavior change of the mechanism system component due to the tolerance of the mechanism component on the CAD diagram using the mechanism analysis model. Means and a change in the behavior of the mechanical system component analyzed by the mechanical analysis executing means with respect to time or the posture of the mechanical component. And a display unit for displaying the CAD diagram creation system on the screen of the CAD drawing creation system, and the mechanism analysis model automatic generation unit generates a link model with a gap calculated based on the input tolerance.
Furthermore, the mechanism analysis execution means is configured to perform a dynamic analysis based on at least one of the external force and the moment of inertia or the mass that is further input, and a mechanical system component accuracy evaluation device characterized in that. 3. A mechanical system component accuracy evaluation device used in a CAD diagram creation system for creating a drawing using a computer, wherein the mechanism is based on a CAD diagram of the mechanical system part created by the CAD diagram creation system. In a system for generating an analysis model and performing a mechanism analysis, a tolerance data input means for inputting a dimensional tolerance or an assembly tolerance of a mechanical part shape displayed in the CAD diagram, and a tolerance input by the tolerance data input means. Mechanism analysis model automatic generation means for automatically generating the mechanism analysis model based on data, and mechanism analysis execution for analyzing the behavior change of the mechanism system component due to the tolerance of the mechanism component on the CAD diagram using the mechanism analysis model. Means and a change in the behavior of the mechanical system component analyzed by the mechanical analysis executing means with respect to time or the posture of the mechanical component. And a display means for displaying on the screen of the CAD drawing creation system display section, and the mechanism analysis model automatic generation means generates a thread model corresponding to the gap calculated based on the input tolerance. A mechanical system component accuracy evaluation apparatus characterized by being configured as follows.