JP7702282B2 - Gear profile design device, gear profile design method, and gear profile design program - Google Patents

Description

The present invention relates to a gear shape design device, a gear shape design method, and a gear shape design program gear shape design device.

Traditionally, various research has been conducted on the shape of gears, which are widely used as power transmission mechanisms. In designing gear shapes, efforts are currently being made to calculate optimal gear shapes using methods such as mechanical analysis by modeling equations of motion, FEM analysis using numerical analysis by the finite element method, and simulation using dedicated software to achieve high speed and high accuracy dynamic evaluation of tooth surface rigidity, either alone or in combination (for example, Non-Patent Document 1).

"Effect of Gear Machining Accuracy and Tooth Surface Modification on Meshing Rigidity of Spur Gear Teeth" by Shu-Ting Lee (Presentation Paper at the 2012 Annual Meeting of the Japan Society of Mechanical Engineers, 2012, No. 12-1)

However, the technology to automatically design the optimal gear shape based on the operator's intentions has not yet been established, and in practice gears are designed using simulations with various variable values set and repeated trial and error.

The present invention has been made in consideration of these circumstances, and aims to provide a gear shape design device, a gear shape design method, and a gear shape design program gear shape design device that can automatically design gears.

In order to solve the above problem, one aspect of the present invention includes an information acquisition unit that acquires specification information including information on the material of the gear and peripheral information on other gears that mesh with the gear when the gear is implemented, and a portion of the gear shape information, and a calculation unit that calculates at least a portion of gear shape information other than the gear shape information acquired by the information acquisition unit, which satisfies a predetermined performance index that indicates the performance of the gear, based on the specification information and shape information acquired by the information acquisition unit.

FIG. 1 is a block diagram of a gear shape design device according to an embodiment of the present invention. FIG. 1 is a flow diagram showing a series of operations performed by the gear shape design device. FIG. 2 is a block diagram of a control program for the gear shape design device.

The following describes in detail an embodiment of the present invention. In the embodiment, a detailed description is given of an example in which a gear shape design device is used to design a spur gear used in a reduction mechanism of an open-loop type six-axis robot arm. In recent years, with an increase in work processes using robot arms, there are more opportunities for humans to work in close proximity to the robot arm. In such cases, noise caused by driving the spur gear used in the robot arm, particularly noise caused by shoulder rotation with a large output or noise caused by meshing between two spur gears (for example, a spur gear on the crank side and an input gear on the motor side) in a reduction mechanism that performs shoulder rotation, is often a problem. Therefore, in the embodiment, an example is described in detail in which the noise of the spur gear is focused on and the shape of the gear that is optimal for reducing noise is calculated.

An overview of the gear shape design device is given below. The gear shape design device outputs information on the optimum gear shape that has the desired performance when an operator inputs required information on the gear shape. In other words, if the operator inputs only the shape conditions (part of the information) that the gear must satisfy at the current stage into the gear shape design device, the gear shape design device outputs the remaining information on the gear shape.

In this case, the gear manufactured based on the information output from the gear shape design device satisfies a predetermined performance index. The performance index is a numerical value indicating the performance of the gear. In addition to the noise mentioned above, the performance of the gear can include gear vibration, efficiency, transmission accuracy, etc. In order to reduce the noise when the gears are driven, it is possible to reduce the meshing stiffness fluctuation when the gears are driven and to reduce the meshing transmission error when the gears are driven. Taking this into account, the gear shape design device outputs shape information that can reduce one or both of the meshing stiffness fluctuation and the meshing transmission error below a desired value. The performance index may be a value input by the operator to the gear shape design device, or it may be determined in advance and stored in the gear shape design device.

The following describes an embodiment. FIG. 1 is a block diagram of a gear shape design device. As shown in FIG. 1, the gear shape design device 1 includes an input unit 2, an information acquisition unit 4, a calculation unit 6, an output unit 8, and a storage unit 10.

The input unit 2 is an interface for the operator to perform various operations. The input unit 2 is composed of an input device of a computer operated by the operator, and is used by the operator to input information to the gear shape design device 1. Information input to the gear shape design device 1 includes gear design information. The gear design information includes gear shape information and gear specification information.

Gear shape information includes information about the overall shape of the gear to be designed and information about the shapes of the individual teeth. Information about the overall shape of the gear includes information about the gear diameter and gear type. Tooth shape information includes information about the dimensions and shapes of the teeth. Tooth shape information includes the amount of tooth crowning and the amount of tooth profile modification.

Gear specification information includes information on the gear material and peripheral information on other gears that mesh with the gear to be designed when the gear is implemented. When implementing a gear in combination with other gears in a reduction mechanism, it is important to take into account the method of connecting the gear to the drive shaft, the gear module, the number of teeth, and the tooth thickness in relation to the peripheral parts. Therefore, the gear specification information includes information on the method of connecting the gear to the drive shaft, the gear module, the number of teeth, and the tooth thickness. In addition, if the gear to be designed is a spur gear used in a reducer (a gear that meshes with the input gear of the reduction mechanism), the number of spur gears can be included in the gear specification information. The specification information may also include constraint information. The constraint information includes information on processing constraints and structural constraints. Processing constraints are constraints related to the manufacturing equipment for gears, and are constraints on shapes, etc. that are difficult to realize with the equipment available when manufacturing gears. Structural constraints include dimensional constraints and durability constraints. Dimensional constraints are constraints on the dimensions of the space that houses the gear. Durability constraints are constraints on the mechanical strength of the gear. Peripheral information is information about the gear that meshes with the gear being designed (sometimes simply called the "counter gear"). Peripheral information includes the number of teeth, tooth thickness, module, and shape of the counter gear.

The information acquisition unit 4 acquires the shape information and specification information input to the input unit 2 from the input unit 2 and supplies the information to the calculation unit 6. When a performance index is input to the input unit 2, the information acquisition unit 4 acquires the performance index from the input unit 2.

The calculation unit 6 calculates at least a portion of the remaining shape information (i.e., at least a portion of the shape information other than the shape information supplied from the information acquisition unit 4) based on the shape information and specification information supplied from the information acquisition unit 4. The shape information calculated by the calculation unit 6 may be only the shape information not input by the operator (i.e., only the remaining shape information), or may be information on the overall shape of a gear, such as a gear design drawing (e.g., 2D or 3D CAD drawing information) created by integrating the input shape information and the remaining shape information. The method of calculating the shape information by the calculation unit 6 will be described later.

The output unit 8 is an interface that outputs the shape information calculated by the calculation unit 6 to the operator. The output unit 8 can be an image display means such as a monitor or an image forming means such as a printer.

The storage unit 10 is composed of a storage medium that stores predetermined information. The information stored in the storage unit 10 is read by the calculation unit 6. The storage unit 10 stores a database that associates shape information, specification information, and performance indexes of previously designed gears. The database is created in advance and stored in the storage unit 10. In constructing the database, a gear designed by the gear shape design device 1 may be actually manufactured and the performance indexes measured using the manufactured gears may be collected, or a simulation may be performed with the gear designed by the gear shape design device 1 to measure the performance index. In other words, the database is constructed from feedback data of the gears designed by the gear shape design device 1. In addition to information on gears that exhibit the desired performance index, the database may also include information on gears that do not exhibit the desired performance index, that is, gears that have caused a malfunction. Furthermore, the performance indexes of gears not designed by the gear shape design device 1 may be measured or simulated and included in the database. Furthermore, an information update unit (not shown) that can acquire information from the outside may be provided so that the database can be updated sequentially.

Next, the calculation unit 6 will be described in more detail. The calculation unit 6 calculates the remaining shape information based on the shape information and specification information acquired by the information acquisition unit 4 and the database stored in the storage unit 10. At this time, the calculation unit 6 calculates shape information such that the performance index (in this example, "mesh stiffness fluctuation") is equal to or less than the desired value. The calculation unit 6 may read out the performance index or the performance index threshold value stored in advance in the storage unit 10, or may acquire the performance index or the performance index threshold value input by the operator via the input unit 2 by the information acquisition unit 4. The calculation unit 6 refers to the database stored in the storage unit 10 and extracts gears that satisfy the shape information and specification information acquired by the information acquisition unit 4 from the database. Furthermore, the calculation unit 6 extracts gears whose mesh stiffness fluctuation is equal to or less than the desired value among the extracted gears. The calculation unit 6 supplies the shape information of the extracted gears to the output unit 8 as the calculation result. At this time, the calculation unit 6 may supply only the shape information of the gear with the smallest mesh stiffness fluctuation to the output unit 8. The calculation unit 6 may also supply to the output unit 8 shape information that lists the shape information of multiple gears in order of least meshing stiffness variation.

The operation of the gear shape design device 1 will be explained below with reference to Figure 2. Figure 2 is a flow diagram showing a series of operations performed by the gear shape design device.

When the operator inputs shape information and specification information into the input unit 2, the gear shape design device 1 starts a series of processes. At this time, it is assumed that only information regarding the overall shape of the gear is input as shape information. In step S1, the gear shape design device 1 acquires the input shape information and specification information using the information acquisition unit 4. Next, in step S2, the gear shape design device 1 calculates the shape information of the gear. In this process, the calculation unit 6 refers to the database stored in the memory unit 10 and also refers to the performance index to calculate the remaining shape information (shape information other than the overall shape of the gear, i.e., tooth shape information). Next, in step S3, the gear shape design device 1 outputs the calculated shape information. This makes it possible to provide the operator with shape information that satisfies the desired performance index.

Figure 3 is a block diagram of the control program of the gear shape design device. The control program is stored in a specified storage medium, and includes instructions that operate each part of the gear shape design device when executed by the gear shape design device.

Referring to Figs. 1 and 3, the control program 20 of the gear shape design device includes an acquisition instruction unit 22 that causes the information acquisition unit 4 to acquire the shape information and specification information input to the input unit 2, a calculation instruction unit 24 that causes the calculation unit 6 to calculate the shape information, and an output instruction unit 26 that causes the output unit 8 to output the shape information. When the control program 20 is executed by the gear shape design device 1, the gear shape design device 1 calculates the shape information according to the flow shown in Fig. 2.

As described above, according to the embodiment, by inputting a portion of multiple pieces of shape information, the remaining shape information can be output. The output shape information satisfies the desired performance index. Therefore, it is not necessary to perform repeated analyses to obtain an optimal gear, or at least the number of analyses can be significantly reduced.

Next, we will explain a variation of the embodiment.

In the above-described embodiment, the calculation unit 6 may calculate manufacturing condition information related to the manufacturing conditions of the gear. The manufacturing condition information is information related to the conditions when the designed gear is actually manufactured. The manufacturing conditions include the allowable tolerance of the gear, the machining conditions of the gear, and the surface treatment conditions of the gear. The manufacturing conditions are stored in a database in the storage unit 10 together with shape information, specification information, and performance index of previously designed gears. The calculation unit 6 supplies the manufacturing condition information associated with the calculated shape information to the output unit 8 together with the shape information.

The operator may also be allowed to input manufacturing condition information into the input unit 2. In this case, the information acquisition unit 4 acquires the manufacturing conditions input into the input unit 2 and supplies them to the calculation unit 6. When extracting gears from the database, the calculation unit 6 extracts gears that satisfy the manufacturing conditions (gears with manufacturing conditions that match the input manufacturing conditions). This makes it possible to provide the operator with shape information for gears manufactured under the manufacturing conditions specified by the operator.

As another variation, the calculation unit 6 may be realized by artificial intelligence. In this case, the calculation unit 6 uses the above-mentioned database to construct a trained model. When the shape information and specification information acquired by the information acquisition unit 4 are input to the calculation unit 6, the calculation unit 6 executes the trained model to calculate shape information that satisfies the desired performance index.

When the calculation unit 6 is realized by artificial intelligence, the operator may be able to classify each piece of information contained in the shape information and specification information into a required condition (must condition) or a desired condition (want condition) when inputting the information into the input unit 2. For example, when inputting the amount of tooth crowning (shape information) and the gear material (specification information) into the input unit 2, this information is classified as a must condition, and the remaining information is classified as a want condition. In this case, the calculation unit 6 calculates a result that satisfies the must conditions and is weighted by the want conditions. This makes it possible to output shape information for gears that satisfy the performance index and at least satisfy the want conditions.

As another modified example, the calculation unit 6 may be configured to use a calculation model that calculates the gear shape information (i.e., the remaining shape information) from the must conditions. In this case, the calculation unit 6 has one or more calculation models. The calculation unit 6 selects a calculation model that satisfies the must conditions and the desired performance index, and calculates the remaining shape information by executing the selected calculation model. The want conditions may be used as weighting coefficients when executing the calculation model.

In the embodiment, the design information is classified into shape information and specification information, and the shape information and specification information are further classified into more detailed information. However, the method of classifying the shape information and specification information is not limited to the example of the embodiment, and the classification method may be changed according to the needs of the design site, so long as it is possible to calculate design information that has not been determined at the stage of using the gear shape design device.

In terms of hardware, each block can be realized by electronic elements and mechanical parts, such as a computer's CPU, and in terms of software, by computer programs, but here we depict functional blocks that are realized by the cooperation of these. Therefore, those skilled in the art will understand that these functional blocks can be realized in various ways by combining hardware and software.

In addition, any combination of the above components, or mutual substitution of the components or expressions of the present invention among methods, devices, programs, temporary or non-temporary storage media on which programs are recorded, systems, etc. are also valid aspects of the present invention.

1 Gear shape design device; 2 Input unit; 4 Information acquisition unit; 6 Calculation unit; 8 Output unit; 10 Storage unit; 20 Control program; 22 Acquisition instruction unit; 24 Calculation instruction unit; 26 Output instruction unit

Claims (8)

an information acquisition unit that acquires specification information including information about a material of a gear for a speed reducer and peripheral information about other gears that mesh with the gear when the gear is installed, a part of multiple pieces of shape information about the gear , and a performance index that indicates the performance of the gear ;
a storage unit in which a database is stored in which the shape information of the gear previously designed, the specification information, and a performance index indicating the performance of the gear are associated with each other;
a calculation unit that refers to the database, extracts gears that satisfy the specification information and the shape information of some of the gears acquired by the information acquisition unit and have a performance index that is a predetermined value or less , and outputs, as a calculation result , at least a part of shape information of the extracted gears other than the shape information of the gears acquired by the information acquisition unit,
the gear is a spur gear,
the specification information includes information regarding the number of the spur gears,
The performance index is at least one of meshing transmission error and meshing stiffness variation . the information acquisition unit acquires constraint information relating to at least one of a structural constraint of a gear and a manufacturing constraint of the gear;
The gear shape design device according to claim 1 , wherein the calculation unit calculates the remaining of the plurality of pieces of shape information by taking into account the constraint information. The gear shape design device according to claim 1 , further comprising an output unit that outputs the shape information obtained by the calculation unit. The gear shape design device according to claim 1 , wherein the calculation unit calculates manufacturing condition information relating to manufacturing conditions of the gear. 5. The gear shape design device according to claim 1, wherein the specification information includes at least one of information on a method of coupling the gear with a drive shaft, information on a number of teeth of the gear, information on a module of the gear, and information on a thickness of the teeth. 6. The gear profile design device according to claim 1 , wherein the shape information includes at least one of an amount of crowning of the gear teeth and an amount of tooth profile modification of the gear teeth. acquiring specification information including information on the material of a gear for a speed reducer and peripheral information on other gears that mesh with the gear when the gear is mounted, a portion of shape information of the gear , and a performance index that indicates the performance of the gear ;
referring to a database in a storage unit in which the database storing the shape information of previously designed gears, the specification information, and a performance index indicating the performance of the gears is stored, extracting gears that satisfy the specification information and shape information of some of the acquired gears and have a performance index equal to or less than a predetermined value , and outputting, as a calculation result , at least a part of shape information of the extracted gears other than the acquired shape information of the gears ,
the gear is a spur gear,
the specification information includes information regarding the number of the spur gears,
wherein the performance index is at least one of meshing transmission error and meshing stiffness variation . A control program for a gear shape design device including an information acquisition unit, a storage unit, and a calculation unit,
Computer,
an acquisition instruction unit that causes the information acquisition unit to acquire specification information including information on the material of the gear, which is a spur gear for a reducer, and peripheral information on other gears that mesh with the gear when the gear is installed, the specification information including information on the number of the spur gears, a part of multiple pieces of shape information of the gear , and a performance index that indicates the performance of the gear, the performance index being at least one of a meshing transmission error and a meshing stiffness variation ; and
a calculation instruction unit which refers to the database in the storage unit in which a database correlating the shape information of the gears designed in the past, the specification information, and a performance index indicating the performance of the gears is stored, extracts gears that satisfy the specification information and the shape information of some of the gears acquired by the information acquisition unit and have the performance index equal to or less than a predetermined value , and outputs as a calculation result at least a part of the shape information of the extracted gears other than the shape information of the gears acquired by the information acquisition unit ;
A control program that functions as a

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