Tooth surface shape optimization system

Abstract

We provide a tooth surface shape optimization system that can optimize tooth surface shape with high precision. [Solution] The tooth surface shape optimization system 1 calculates the optimized tooth surface shape of a gear. The tooth surface shape optimization system 1 includes a tooth surface shape optimization unit 14 that calculates an optimized tooth surface shape, which is the optimized tooth surface shape, by performing calculations to optimize the tooth surface shape based on constraints relating to either the tooth surface shape of the gear or the method of machining the tooth surface of the gear; a gear machining simulation unit 25 for calculating constraints that simulates the machining of the tooth surface based on the gear specifications of the gear and the method of machining the tooth surface of the gear in order to calculate the constraints; and a constraint calculation unit 28 that calculates the constraints based on the simulation results of the gear machining simulation unit 25 for calculating constraints.

Description

Technical Field

[0001] The present invention relates to a tooth surface shape optimization system.

Background Art

[0002] Conventionally, there is a tooth surface shape optimization system for efficiently designing the complex tooth surface shape of a gear or designing a tooth surface shape in which the performance of the gear and its mating gear reaches the desired performance. As such a tooth surface shape optimization system, Patent Document 1 discloses an apparatus including a configuration in which principal component analysis is performed on a plurality of tooth surface shape data to obtain a plurality of principal component shape data, and the tooth surface shape is evaluated based on the plurality of principal component shape data. Further, Patent Document 2 discloses a support apparatus for designing a tooth surface shape in which the performance of a gear and its mating gear reaches the desired performance.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the configurations disclosed in Patent Documents 1 and 2 do not take into account jig interference and errors that occur during gear machining, resulting in discrepancies between the tooth surface shape obtained during mass production of gears and the actual tooth surface shape. Therefore, there is room for improvement in optimizing the tooth surface shape with high precision. Furthermore, in tooth surface formation using generation machining methods such as gear grinding (continuous generation grinding) and skiving, bias correction occurs as an error when crowning correction is applied. Such errors are not considered in the configurations disclosed in Patent Documents 1 and 2, so there is room for improvement in optimizing the tooth surface shape with high precision. In addition, minute undulations occur on the tooth surface of gears depending on the machining method, so there is room for improvement in optimizing the tooth surface shape with high precision.

[0005] The present invention aims to provide a tooth surface shape optimization system that can optimize tooth surface shape with high precision. [Means for solving the problem]

[0006] One aspect of the present invention is, A gear tooth shape optimization system for calculating the optimized tooth surface shape, A tooth surface shape optimization unit calculates an optimized tooth surface shape, which is the optimized tooth surface shape, by performing calculations to optimize the tooth surface shape based on constraints relating to either the tooth surface shape of the gear or the method of machining the tooth surface of the gear. In order to calculate the aforementioned constraints, a gear machining simulation unit for calculating constraints simulates the machining of the tooth surface based on the gear specifications of the gear and the machining method of the tooth surface of the gear, A constraint calculation unit calculates the constraints based on the simulation results of the gear machining simulation unit for calculating the constraints, It is included in the tooth surface shape optimization system. [Effects of the Invention]

[0007] According to one embodiment of the present invention, a tooth surface shape optimization system simulates the machining of the tooth surface based on the gear specifications and the machining method of the gear tooth surface, and calculates constraints on the gear tooth surface shape and machining method based on the simulation results. Then, the tooth surface shape is optimized under these constraints. This allows for the inclusion of jig interference and errors that occur during gear machining in the optimization of the tooth surface shape, thereby excluding gear shapes, gear specifications, and tooth surface shapes that cannot be machined from the candidate solutions for optimization, and enabling high-precision optimization of the tooth surface shape. Furthermore, by optimizing the tooth surface shape under the above constraints, errors in bias correction that occur when crowning correction is applied in gear grinding and skiving processes are also taken into consideration, as well as minute undulations that occur on the tooth surface depending on the machining method, thus enabling high-precision optimization of the tooth surface shape.

[0008] As described above, according to the above embodiment, a tooth surface shape optimization system can be provided that can optimize the tooth surface shape with high precision. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows the configuration of the tooth surface shape optimization system in Embodiment 1. [Figure 2] This is a conceptual diagram of the processing machine in Embodiment 1. [Figure 3] (a) is a conceptual diagram showing the tooth surface shape before modification, and (b) to (f) are conceptual diagrams showing the tooth surface modification elements and the tooth surface shape after modification. [Figure 4] (a) A conceptual diagram of the tooth surface shape after tooth surface modification with crowning adjustment applied, and (b) A conceptual diagram showing the error between the tooth surface shape after the tooth surface modification and the involute tooth profile. [Figure 5] This is a conceptual diagram showing the positional relationship between the tool and the workpiece in the processing machine in Embodiment 1. [Figure 6] This is a conceptual diagram showing the relationship between the center-to-center distance correction amount and the tool feed amount in Embodiment 1. [Figure 7](a) A conceptual diagram showing the relationship between the coefficient of change in intercenter distance and the bias adjustment amount, (b) A conceptual diagram showing the relationship between the coefficient of change in intercenter distance and the crowning adjustment amount, and (c) A conceptual diagram showing the relationship between the bias adjustment amount and the crowning adjustment amount. [Figure 8] This is a conceptual diagram showing the correlation between the bias correction amount and the change in tool rotation angle when bias correction is performed during gear skiving in Embodiment 1. [Figure 9] This is a first flowchart illustrating the method for determining the optimized tooth surface shape in Embodiment 1. [Figure 10] This is a second flowchart illustrating the method for determining the optimized tooth surface shape in Embodiment 1. [Figure 11] This is a conceptual diagram showing an example of tooth surface data output from the optimized tooth surface shape evaluation unit in Embodiment 1. [Modes for carrying out the invention]

[0010] (Embodiment 1) 1. Configuration of Tooth Surface Shape Optimization System 1 Embodiments of the above-described gear tooth shape optimization system will be explained with reference to Figures 1 to 11. As shown in Figure 1, the gear tooth shape optimization system 1 includes a gear design system 1a and a gear machining simulation system 1b. The two systems cooperate with each other to optimize the gear tooth shape. The form of the gear to be machined in the gear tooth shape optimization system 1 is not limited and may be an external gear or an internal gear, and may be a helical gear or a spur gear.

[0011] In the tooth surface shape optimization system 1, the processing machine for gear processing can adopt a 5-axis machining center having three linear axes and two rotational axes as drive axes for changing the relative position and orientation of the workpiece to be processed and the tool. In the present embodiment, as shown in FIG. 2, the processing machine 50 has three orthogonal linear axes (X-axis, Y-axis, Z-axis) as linear axes, and B-axis and Cw-axis as rotational axes. The B-axis is a rotational axis around the central axis RB of the rotary table 54 parallel to the Y-axis line, and the Cw-axis is a rotational axis around the central axis RW of the workpiece W. Note that the processing machine 50 has a Ct-axis which is a rotational axis around the central axis RT of the tool T, and including the Ct-axis, it becomes a 6-axis machining center.

[0012] The processing machine 50 shown in FIG. 2 includes a tool spindle 51 that supports the tool T and is rotatable about the Ct-axis, and is movable in the Y-axis direction and the Z-axis direction, respectively. Further, the processing machine 50 includes a workpiece spindle 52 that supports the workpiece W and is rotatable about the Cw-axis, and is rotatable about the B-axis, and is movable in the X-axis direction. The processing machine 50 includes a processing control unit 53 and the like for performing operation control of gear tooth processing. In the present embodiment, the case where the processing control unit 53 performs control for machining gear teeth on the workpiece W by skiving will be described. However, it can also be applied to gear grinding with a thread-shaped grinding wheel and gear cutting by hobbing. Note that it is not limited to the above configuration, and the tool spindle 51 and the workpiece spindle 52 may have a configuration that allows relative movement.

[0013] In the tooth surface shape optimization system 1 shown in FIG. 1, both the gear design system 1a and the gear processing simulation system 1b are composed of an arithmetic unit capable of executing a predetermined program and a storage unit capable of storing predetermined information. Each system will be described in detail below.

[0014] 2. Configuration of Gear Design System 1a As shown in FIG. 1, the gear design system 1a includes a basic structure determination unit 10, a case rigidity prediction unit 11, a misalignment prediction unit 12, a gear specification determination unit 13, a tooth surface shape optimization unit 14, a gear pair performance prediction and determination unit 15, and a tooth surface shape determination unit 16.

[0015] 2-1.Basic structure determination part 10 The basic structure determination unit 10 determines the overall structure of the device having the gear to be machined. The matters to be determined include the shape and size of the various parts that make up the device, and the operating conditions of the device, and in the case of automobile parts, it may also include operating conditions.

[0016] 2-2. Case stiffness prediction unit 11, misalignment prediction unit 12 The case stiffness prediction unit 11 predicts the stiffness of the case in the device determined by the basic structure determination unit 10. The misalignment prediction unit 12 predicts the arrangement of the gears in the device determined by the basic structure determination unit 10. The misalignment prediction unit 12 predicts the misalignment, which is the deviation of the central axis between gear pairs of gears to be machined.

[0017] 2-3. Gear Specifications Determination Unit 13 The gear specification determination unit 13 determines the gear specifications, which are the specifications of the gear to be machined. The gear specifications include various elements of the gear as shown in the drawing. In addition to the gear specifications, the gear specification determination unit 13 also determines the machining method for forming the tooth surface of the gear. The machining method is not limited, and depending on the shape of the gear, hobbing, gear grinding, gear skiving, etc., can be used.

[0018] 2-4. Tooth surface shape optimization section 14 The tooth surface shape optimization unit 14 performs optimization based on the gear parameters determined by the gear parameter determination unit 13. It sets the gear tooth surface modification amount as an explanatory function, sets a predetermined performance of the gear as an objective function, and uses the constraints calculated by the constraint calculation unit 28 (described later) as constraints. The optimization method is not limited; known optimization methods such as genetic algorithms, simulated annealing, particle optimization, and experimentally designed response surface methods can be employed. The optimized tooth surface shape based on the tooth surface modification amount optimized by the tooth surface shape optimization unit 14 is evaluated by the optimized tooth surface shape evaluation unit 34 (described later).

[0019] The calculation result of the tooth surface shape optimization unit 14 may be a Pareto solution containing multiple optimal solutions, and the optimized tooth surface shape can be arbitrarily extracted from the Pareto solution. The calculation of the optimal solution in the tooth surface shape optimization unit 14 may be performed in multiple stages. That is, in the first stage, a first Pareto solution may be derived as the first optimal solution by using a specific tooth surface modification element as the first explanatory variable, and then in the second stage, the value of the first explanatory variable in the first Pareto solution may be set to a constant, and a second Pareto solution may be derived as the second optimal solution by using other tooth surface modification elements as the second explanatory variable.

[0020] Tooth surface modification can be performed by combining known tooth surface modification elements with the tooth surface W1 shown in Figure 3(a) before modification. Examples of tooth surface modification elements include, for example, tooth trace direction inclination (helix angle modification) shown in Figure 3(b), pressure angle modification shown in Figure 3(c), tooth profile crowning (tooth profile rounding modification) shown in Figure 3(d), tooth trace crowning shown in Figure 3(e), bias modification shown in Figure 3(f), and end relief shown in Figure 3(g), one or more of these can be combined. In Figures 3(b) to (g), tooth surface W2 shows the tooth surface shape after modification by the corresponding tooth surface modification element. Although not shown, tooth surface modification elements may also include tip modification and other arbitrary shape elements.

[0021] Of the elements of tooth surface modification, pressure angle modification and tooth profile rounding modification are modifications in the tooth profile direction and represent a transfer of the tool shape. That is, they can be modified by the tooth profile of the tool T. On the other hand, tooth trace crowning, bias modification, and helix angle modification are modifications in the tooth width direction and represent a transfer of the motion trajectory of the machining center 50. That is, they can be modified by the machining control elements of the machining center 50, namely the Cw axis, B axis, X axis, and Y axis. Although pressure angle modification can be modified by machining control elements including setting conditions such as the intersection angle and offset angle (machining position) of the machining center 50, in this embodiment it is modified based on the tool specifications of the tool T.

[0022] 2-5. Gear performance prediction and determination unit 15, tooth surface shape determination unit 16 The gear performance prediction and determination unit 15 predicts the performance of a gear having an optimized tooth surface shape evaluated by the optimized tooth surface shape evaluation unit 34 (described later), and determines whether or not it meets the target performance. The tooth surface shape determination unit 16 determines the tooth surface shape of the gear to be machined to the optimized tooth surface shape determined by the gear performance prediction and determination unit 15 to meet the target performance.

[0023] 3. Gear Machining Simulation System 1b As shown in Figure 1, the gear machining simulation system 1b includes a tool specification design unit 20, a jig tool design unit 21, an interference determination unit 22, a machine tool motion calculation unit for calculating constraints 23, a tool tooth profile calculation unit for calculating constraints 24, a gear machining simulation unit for calculating constraints 25, a tooth surface shape evaluation unit for calculating constraints 26, a correlation calculation unit 27, a constraint calculation unit 28, a machine tool motion calculation unit for evaluating optimized tooth surfaces 29, a tool tooth profile calculation unit for evaluating optimized tooth surfaces 30, a gear machining simulation unit for evaluating optimized tooth surfaces 31, a jig tool motion characteristic acquisition unit 32, a machining motion characteristic acquisition unit 33, and an optimized tooth surface shape evaluation unit 34.

[0024] 3-1. Tool specification design unit 20, jig and tool design unit 21, interference determination unit 22 The tool specification design unit 20 designs the tool specifications, which are the specifications of the tool T to be installed in the machining center that performs gear machining. The tool specifications are designed by the jig tool design unit 21 based on the gear specifications and machining method determined by the gear specification determination unit 13. The tool specifications to be designed include, for example, the number of teeth of the tool T, the outer diameter of the tool T, the helix angle of the tool T, the rake angle, the side relief angle, and the front relief angle. The interference determination unit 22 then determines whether or not there is interference between the tool T designed by the tool specification design unit 20 and the workpiece W on which the tooth surface is formed. If interference is determined to exist, the gear specifications can be readjusted.

[0025] 3-2. Processing machine motion calculation unit 23 for constraint calculation The machine motion calculation unit 23 for calculating constraint conditions calculates the motion of the machine 50 when machining the tooth surface, based on the gear specifications and machining method, when the interference determination unit 22 determines that there is no interference between the tool T designed by the tool specification design unit 20 and the workpiece W, in order to calculate the constraint conditions described later. The motion of the machine 50 calculated by the machine motion calculation unit 23 for calculating constraint conditions includes, for example, changes in the distance between the centers of the tool T and the workpiece W, changes in the workpiece rotation angle, and changes in the intersection angle.

[0026] 3-3. Tool tooth profile calculation unit 24 for calculating constraint conditions The constraint calculation tool tooth profile calculation unit 24 calculates the tooth profile of the tool T provided in the machining center 50 based on the gear specifications of the gear, the machining method, and the motion of the machining center 50 calculated by the constraint calculation machine motion calculation unit 23, in order to calculate the constraint conditions described later.

[0027] 3-4. Gear machining simulation unit 25 for calculating constraints In order to calculate the constraints described later, the machining of the tooth surface by a machining center 50 equipped with a tool T having a tooth profile calculated by the constraint calculation tool tooth profile calculation unit 24 is simulated.

[0028] 3-5. Tooth surface shape evaluation unit 26 for calculating constraint conditions In order to calculate the constraints described later, the tooth surface shape is evaluated based on the simulation results of the gear machining simulation unit 25 for calculating constraints. The tooth surface shape is evaluated by calculating the amount of each tooth surface modification shown in Figures 3(b) to (g).

[0029] 3-6. Correlation calculation unit 27, constraint calculation unit 28 The correlation calculation unit 27 calculates the correlation between the change in machine motion calculated by the machine motion calculation unit 23 for calculating constraint conditions and the amount of modification determined by the tooth surface shape evaluation unit 26 for calculating constraint conditions. The constraint condition calculation unit 28 calculates the constraint conditions for optimization by the tooth surface shape optimization unit 14 described above from the correlation calculated by the correlation calculation unit 27. In this embodiment, for example, the relationship between the amount of tooth crowning modification shown in Figure 3(d) and the amount of bias modification shown in Figure 3(f), the relationship between the amount of end relief modification shown in Figure 3(g) and the amount of bias modification shown in Figure 3(f), and the maximum amount of modification depending on the machining method can be calculated as constraint conditions.

[0030] Here, the relationship between bias correction and crowning correction in gear skiving is described in detail below. First, in gear grinding using a screw-shaped grinding wheel as the tool T, when crowning correction is performed as tooth surface correction, the formed tooth surface shape has the relationship shown in Figure 3(b) when comparing the error with respect to the involute tooth profile between cross-section A at one side of the tooth trace direction, cross-section C at the other side, and cross-section B at the position between the two, as shown in Figure 3(a). That is, the error in the tooth profile direction is symmetrical between cross-section A at one side of the tooth trace direction and cross-section C at the other side, indicating that bias correction has occurred.

[0031] Furthermore, when crowning is performed as a tooth surface modification, as shown in Figure 5, the distance between the central axis Wa and the central axis Ta is corrected so that the trajectory Tb of the central axis Ta of the tool T, which is made of a screw-shaped grinding wheel, traces an arc with respect to the central axis Wa of the workpiece W during machining. Here, as shown in Figure 6, the relationship between the amount of correction (amount of correction for the distance between centers) y and the feed amount x of the tool T in the axial direction X of the workpiece has the following relationship (1).

[0032] y=ηx 2 …(1)

[0033] Furthermore, the relationship between the center-to-center distance change coefficient η and the bias adjustment amount in equation (1) above is shown in Figure 7(a). Also, the relationship between the center-to-center distance change coefficient η and the crowning adjustment amount is shown in Figure 7(b). From these, it was derived that the bias adjustment amount and the crowning adjustment amount have a linear relationship as shown in Figure 7(c). Therefore, when the bias adjustment amount is denoted as BS and the crowning adjustment amount as CR, the following relationship equation (2) holds true as the correspondence between the two.

[0034] CR = α × BS …(2) (α is a coefficient)

[0035] Therefore, in optimizing the tooth surface modification amount, by setting the constraint that the crowning modification amount and the bias modification amount satisfy the above relationship, the bias modification amount when a crowning modification amount is applied can be made to match the so-called natural bias. This allows for the design of tooth surface modification amounts according to the processing method for mass production, and enables highly accurate performance prediction.

[0036] Furthermore, when bias correction is performed during gear skiving, the relationship between the bias correction amount and the change in tool rotation angle is, for example, as shown in Figure 8. In order for gear skiving to be possible, the change in the intersection angle must be smaller than the sum of the lateral relief angles of the left and right tooth faces. Therefore, in the example shown in Figure 8, by setting constraints that regulate the bias correction amount so that the change in tool rotation angle is within a predetermined range, it is possible to ensure that gear skiving is possible.

[0037] Furthermore, in gear grinding, bias correction requires changing the cross-sectional shape of the grinding wheel according to its axial position. Therefore, the limit is the point where the width of the tip of the grinding wheel's teeth can be secured and the cross-section of the grinding wheel is established. By setting constraints so that the amount of bias correction that can be processed with that grinding wheel is the upper limit, it is possible to ensure that the width of the tooth tip is secured and that hobbing and gear grinding are possible. The same applies to hobbing.

[0038] 3-7. Machine motion calculation unit 29 for optimized tooth surface evaluation The optimized tooth surface evaluation machine motion calculation unit 29 calculates the motion of the machine when the tooth surface is machined by the machine 50, based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and conditions for machining the gear tooth surface, and the dynamic characteristics of the machine 50, in order to evaluate the optimized tooth surface shape calculated by the tooth surface shape optimization unit 14 described above.

[0039] 3-8. Tool tooth profile calculation unit 30 for optimized tooth surface evaluation The optimized tooth surface evaluation tool tooth profile calculation unit 30 calculates the tooth profile of the tool T provided in the machining center 50 based on the gear specifications of a gear having an optimized tooth surface shape, the machining method and conditions for machining the gear tooth surface, and the calculation results of the optimized tooth surface evaluation machining center motion calculation unit. Here, the machining conditions include, for example, the cycle time in gear machining, whether it is single-tooth surface machining or double-tooth surface machining, and whether bias correction machining is required. In the case of double-tooth surface machining, one tooth surface is formed to an optimized tooth surface shape, while the other tooth surface is formed as is.

[0040] 3-9. Gear machining simulation unit 31 for optimized tooth surface evaluation, The gear machining simulation unit 31 for evaluating optimized tooth surface shapes simulates the machining of the tooth surface by the machining machine 50 based on the gear specifications of a gear having an optimized tooth surface shape, the machining method and conditions for machining the gear tooth surface, and the dynamic characteristics of the machining machine 50, in order to evaluate the optimized tooth surface shape. The dynamic characteristics of the machining machine 50 are acquired by the jig tool dynamic characteristics acquisition unit 32 and the machining machine dynamic characteristics acquisition unit 33.

[0041] 3-10. Optimized tooth surface shape evaluation unit 34 The optimized tooth surface shape evaluation unit 34 evaluates the optimized tooth surface shape based on the simulation results of the gear machining simulation unit 31 for optimized tooth surface evaluation. The optimized tooth surface shape evaluation unit 34 then outputs tooth surface data of the optimized tooth surface shape.

[0042] 4. Method for determining the optimal tooth surface shape Next, the method for determining the optimized tooth surface shape using the tooth surface shape optimization system 1 of this embodiment will be explained with reference to Figures 9 and 10. First, in step S1 of Figure 9, the basic structure determination unit 10 of the gear design system 1a determines the basic structure of the apparatus including the gear to be machined. Then, in step S2, the case rigidity of the apparatus including the gear to be machined is predicted. In step S3, the misalignment prediction unit 12 predicts the misalignment in the gear pair including the gear to be machined. After that, in step S4, the gear specification determination unit 13 determines the gear specifications and machining method for the gear to be machined.

[0043] Then, the process proceeds to step S5, where the tool specification design unit 20 in the gear machining simulation system 1b designs the tool specifications based on the gear specifications and machining method. In step S6, the jig tool design unit 21 designs the tool T and jig to be used in the gear machining simulation. In step S7, the interference determination unit 22 determines whether or not there is interference between the tool T and the workpiece W. If it is determined that there is interference between the tool T and the workpiece W, the process proceeds to Yes in step S7 and returns to step S4.

[0044] On the other hand, if it is determined in step S7 that there is no interference between the tool T and the workpiece W, the process proceeds to step S7 No. Then, in step S8, the machine motion calculation unit 23 for calculating constraints calculates the motion of the machine 50 in order to calculate the constraints. The process then proceeds to step S9, where the tool tooth profile calculation unit 24 for calculating constraints calculates the tool tooth profile in order to calculate the constraints.

[0045] Subsequently, in step S10, the gear machining simulation unit 25 for calculating constraints performs a gear machining simulation to calculate the constraints. Then, in step S11, the tooth surface shape evaluation unit 26 for calculating constraints evaluates the tooth surface shape based on the results of the gear machining simulation.

[0046] Next, in step S12, the correlation calculation unit 27 calculates the correlation between the motion of the machining center 50 and the amount of tooth surface modification, based on the evaluation results from the tooth surface shape evaluation unit 26 for calculating constraint conditions. Then, in step S13, the constraint conditions for optimizing the tooth surface shape are calculated based on the correlation calculated by the correlation calculation unit 27, and the process proceeds to symbol A.

[0047] Then, proceeding from reference numeral A in Figure 10 to step S14, the tooth surface shape optimization unit 14 in the gear design system 1a optimizes the tooth surface shape. Subsequently, in step S15, the optimized tooth surface evaluation machine motion calculation unit 29 in the gear machining simulation system 1b calculates the motion of the machine 50 when machining the tooth surface, based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and conditions of the gear tooth surface, and the dynamic characteristics of the machine 50, in order to evaluate the optimized tooth surface shape.

[0048] Furthermore, in step S16, the optimized tooth surface evaluation tool tooth profile calculation unit 30 calculates the tooth profile of the tool T provided in the machining center 50 based on the gear specifications of the gear having an optimized tooth surface shape, the machining method and conditions for the gear tooth surface, and the calculation results of the optimized tooth surface evaluation machining center motion calculation unit 29.

[0049] Subsequently, in step S17, the gear machining simulation unit 31 for evaluating the optimized tooth surface shape simulates the machining of the tooth surface by the machining machine 50 based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and conditions for the gear tooth surface, and the dynamic characteristics of the machining machine 50 acquired by the jig tool dynamic characteristics acquisition unit 32 and the machining machine dynamic characteristics acquisition unit 33, in order to evaluate the optimized tooth surface shape.

[0050] Then, in step S18, the optimized tooth surface shape evaluation unit 34 evaluates the optimized tooth surface shape based on the simulation results of the gear machining simulation unit 31 for optimized tooth surface evaluation. The optimized tooth surface shape evaluation unit 34 then outputs tooth surface data of the optimized tooth surface shape. For example, it outputs the tooth surface data shown in Figure 11.

[0051] Subsequently, in step S19, the gear performance prediction and determination unit 15 in the gear design system 1a predicts the performance of the gear having the optimized tooth surface shape based on the tooth surface data output from the optimized tooth surface shape evaluation unit 34, and in step S20, the gear performance prediction and determination unit 15 determines whether or not the target performance is met.

[0052] If it is determined in step S20 that the target performance is not met, proceed to step S20 No., then proceed from symbol B to step S14 to perform optimization again, and then carry out the subsequent steps. Note that the second optimization may involve selecting another optimal solution from the group of optimal solutions obtained in the previous optimization. If step S14 has already been performed again, proceed from symbol C to step S4 shown in Figure 9 instead of symbol B, determine the gear specifications again, and then carry out the subsequent steps. If step S4 has already been performed again, proceed from symbol D to step S1 shown in Figure 9 instead of symbol C, and then carry out the subsequent steps.

[0053] On the other hand, if it is determined in step S20 that the target performance is met, the process proceeds to Yes in step S20, and in step S21, the tooth surface shape determination unit 16 determines the tooth surface shape of the gear to be machined. This completes the process.

[0054] 5. Effects of the Tooth Surface Shape Optimization System 1 of Embodiment 1 According to the tooth surface shape optimization system 1 of Embodiment 1, the machining of the tooth surface is simulated based on the gear specifications and the machining method of the gear tooth surface, and constraints on the gear tooth surface shape and machining method are calculated based on the simulation results. Then, the tooth surface shape is optimized under these constraints. This makes it possible to exclude shapes that cannot be machined from the optimization solution. Furthermore, by optimizing the tooth surface shape under the above constraints, in gear grinding and skiving processes, the bias correction error that occurs when crowning correction is applied is also taken into consideration, as well as minute undulations that occur on the tooth surface depending on the machining method. As a result, the accuracy of predicting the performance of the gear pair is improved, and optimization can be performed with high precision.

[0055] Furthermore, in this embodiment, the gear machining simulation unit 25 for calculating constraints includes a tool specification design unit 20 that designs the specifications of a tool T provided in a machining center 50 for machining the gear tooth surface based on the gear specifications and the tooth surface machining method, and an interference determination unit 22 that determines whether or not there is interference between the tool T having the tool specifications designed by the tool specification design unit 20 and the gear. The gear machining simulation unit 25 for calculating constraints simulates the machining of the tooth surface when the interference determination unit 22 determines that there is no interference. This allows the simulation of the machining of the tooth surface to be performed in a state where the tool T and the gear do not interfere with each other, thereby improving the accuracy of the simulation of tooth surface machining for calculating constraints.

[0056] Furthermore, in this embodiment, in order to calculate the constraint conditions, the system includes a constraint condition calculation machine motion calculation unit 23 that calculates the motion of the machine 50 when the machine 50 processes the tooth surface based on the gear specifications and the tooth surface processing method, and a constraint condition calculation tool tooth profile calculation unit 24 that calculates the tooth profile of the tool T provided in the machine 50 based on the gear specifications, the tooth surface processing method, and the calculation results of the constraint condition calculation machine motion calculation unit 23. The constraint condition calculation gear processing simulation unit 25 then simulates the processing of the tooth surface by the machine 50 equipped with the tool T having the tooth profile calculated by the constraint condition calculation tool tooth profile calculation unit 24. This improves the accuracy of the tooth surface processing simulation for calculating the constraint conditions.

[0057] Furthermore, in this embodiment, the constraint condition calculation unit 28 includes a tooth surface shape evaluation unit 26 for calculating constraint conditions that calculates the amount of tooth surface modification by evaluating the tooth surface shape based on the simulation results of the gear machining simulation unit 25 for calculating constraint conditions, and a correlation calculation unit 27 that calculates the correlation between the amount of change in the motion of the machining center 50 calculated by the machining center motion calculation unit 23 for calculating constraint conditions and the amount of modification determined by the tooth surface shape evaluation unit 26 for calculating constraint conditions. The constraint condition calculation unit 28 calculates constraint conditions based on the calculation results of the correlation calculation unit 27. As a result, constraint conditions are set regarding the amount of tooth surface shape modification in the optimization of the tooth surface shape, thereby improving the accuracy of the optimized tooth surface shape.

[0058] Furthermore, in this embodiment, in order to evaluate the optimized tooth surface shape, the gear machining simulation unit 31 for evaluating the optimized tooth surface shape is included, which simulates the machining of the tooth surface by the machining machine 50 based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and conditions of the gear tooth surface, and the dynamic characteristics of the machining machine 50. This makes it possible to improve the accuracy of the optimized tooth surface shape.

[0059] Furthermore, in this embodiment, in order to evaluate the optimized tooth surface shape, the system includes: an optimized tooth surface evaluation machine motion calculation unit 29 that calculates the motion of the machine 50 when the tooth surface is machined by the machine 50 based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and conditions for machining the gear tooth surface, and the dynamic characteristics of the machine 50; and an optimized tooth surface evaluation tool tooth profile calculation unit 30 that calculates the tooth profile of the tool T provided in the machine 50 based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and conditions for machining the gear tooth surface, and the calculation results of the optimized tooth surface evaluation machine motion calculation unit 29. In addition, the optimized tooth surface evaluation gear machining simulation unit 31 simulates the machining of the tooth surface by the machine 50 equipped with the tool T having the tooth profile calculated by the optimized tooth surface evaluation tool tooth profile calculation unit 30. This makes it possible to improve the accuracy of the optimized tooth surface shape.

[0060] Furthermore, this embodiment includes a gear pair performance prediction and determination unit 15 that predicts the performance of a gear pair including a gear having the tooth surface shape from the simulation results of the gear machining simulation unit 31 for optimized tooth surface evaluation, and determines whether or not it meets the target performance. This makes it possible to optimize the tooth surface shape to meet the target performance.

[0061] Furthermore, in this embodiment, the gear performance prediction and determination unit 15 determines the optimal tooth surface shape again in the tooth surface shape optimization unit 14 based on the determination result. This improves the accuracy of tooth surface shape optimization.

[0062] Furthermore, in this embodiment, the gear specifications are changed based on the determination result of the gear performance prediction and determination unit 15. This improves the accuracy of the optimization of the tooth surface shape.

[0063] Furthermore, in this embodiment, the machining conditions are changed based on the determination result of the gear performance prediction and determination unit. This improves the accuracy of the tooth surface shape optimization.

[0064] As described above, this embodiment provides a tooth surface shape optimization system 1 that can optimize tooth surface shape with high precision. [Explanation of Symbols]

[0065] 1. Tooth surface shape optimization system 1a Gear design system 1b Gear Machining Simulation System 10 Basic structure determination part 11 Case rigidity prediction section 12. Misalignment prediction unit 13 Gear Specifications Determination Unit 14 Tooth surface shape optimization section 15 Gear performance prediction and determination unit 16 Tooth surface shape determination section 20 Tool specification design department 21. Jig and Tool Design Department 22 Interference detection unit 23 Processing machine motion calculation unit for constraint condition calculation 24 Tool tooth profile calculation unit for calculating constraints 25 Gear Machining Simulation Unit for Calculating Constraint Conditions 26 Tooth surface shape evaluation unit for calculating constraints 27 Correlation Calculation Unit 28 Constraint condition calculation section 29. Machine motion calculation unit for optimized tooth surface evaluation 30 Tool tooth profile calculation unit for optimized tooth surface evaluation 31 Gear Machining Simulation Unit for Optimized Tooth Surface Evaluation 32. Jig and tool movement characteristic acquisition unit 33 Machining motion characteristics acquisition section 34 Optimized tooth surface shape evaluation unit 50 Processing machine

Claims

1. A gear tooth shape optimization system for calculating the optimized tooth surface shape, A tooth surface shape optimization unit calculates an optimized tooth surface shape, which is the optimized tooth surface shape, by performing calculations to optimize the tooth surface shape based on constraints relating to either the tooth surface shape of the gear or the method of machining the tooth surface of the gear. In order to calculate the aforementioned constraints, a gear machining simulation unit for calculating constraints simulates the machining of the tooth surface based on the gear specifications of the gear and the machining method of the tooth surface of the gear, A constraint calculation unit calculates the constraints based on the simulation results of the gear machining simulation unit for calculating the constraints, A tooth surface shape optimization system, including the above.

2. A tool specification design unit that designs the specifications of a tool to be installed in a machining center that processes the tooth surface of the gear, based on the gear specifications of the gear and the method for machining the tooth surface of the gear, It includes an interference determination unit that determines whether or not there is interference between a tool having tool specifications designed by the tool specification design unit and the gear, The gear machining simulation unit for calculating constraint conditions simulates the machining of the tooth surface when the interference determination unit determines that there is no interference, in the tooth surface shape optimization system according to claim 1.

3. To calculate the aforementioned constraints, a constraint condition calculation machine motion calculation unit calculates the motion of the machine when the machine processes the tooth surface based on the gear specifications of the gear and the method of machining the tooth surface, The system includes a constraint condition calculation tool tooth profile calculation unit that calculates the tooth profile of a tool provided in the machine based on the gear specifications of the gear, the machining method of the gear tooth surface, and the calculation results of the constraint condition calculation machine motion calculation unit. The gear machining simulation unit for calculating constraint conditions simulates the machining of the tooth surface by the machining machine equipped with the tool having the tooth profile calculated by the tool tooth profile calculation unit for calculating constraint conditions, according to claim 2.

4. A gear machining simulation unit for calculating constraints evaluates the tooth surface shape based on the simulation results of the gear machining simulation unit for calculating constraints, and calculates the amount of modification to the tooth surface. It includes a correlation calculation unit that calculates the correlation between the amount of change in the motion of the machine calculated by the machine motion calculation unit for calculating constraint conditions and the amount of modification determined by the tooth surface shape evaluation unit for calculating constraint conditions, The tooth surface shape optimization system according to claim 3, wherein the constraint condition calculation unit calculates the constraint conditions based on the calculation results of the correlation calculation unit.

5. A gear tooth surface shape optimization system according to any one of claims 1 to 4, comprising an optimized tooth surface evaluation gear machining simulation unit that simulates the machining of the tooth surface by a machining machine based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and conditions for machining the tooth surface of the gear, and the dynamic characteristics of the machining machine that machines the tooth surface of the gear, in order to evaluate the optimized tooth surface shape.

6. In order to evaluate the optimized tooth surface shape, an optimized tooth surface evaluation machine motion calculation unit calculates the motion of the machine when the tooth surface is machined by the machine, based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and machining conditions of the gear tooth surface, and the dynamic characteristics of the machine. The system includes an optimized tooth surface evaluation tool tooth profile calculation unit that calculates the tooth profile of a tool provided in the machine based on the gear specifications of the gear having the optimized tooth surface shape, the machining method and conditions for the gear tooth surface, and the calculation results of the optimized tooth surface evaluation machine motion calculation unit. The gear surface shape optimization system according to claim 5, wherein the gear surface machining simulation unit for optimized tooth surface evaluation simulates the machining of the tooth surface by the machining machine equipped with the tool having the tooth profile calculated by the tool tooth profile calculation unit for optimized tooth surface evaluation.

7. The gear tooth shape optimization system according to claim 5, further comprising a gear pair performance prediction and determination unit that predicts the performance of a gear pair including the gear having the gear tooth shape in the simulation results of the gear machining simulation unit for optimized tooth surface evaluation, and determines whether or not it satisfies the target performance.

8. The tooth surface shape optimization system according to claim 7, wherein the tooth surface shape optimization unit recalculates the optimized tooth surface shape based on the determination result of the gear performance prediction determination unit.

9. The tooth surface shape optimization system according to claim 7, wherein the gear specifications of the gear are changed based on the determination result of the gear performance prediction determination unit.

10. The tooth surface shape optimization system according to claim 7, wherein the machining conditions are changed based on the determination result of the gear performance prediction determination unit.

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