WO2020049370A1

WO2020049370A1 - Press device, terminal device, estimated-ball-screw-lifespan calculation method, and program

Info

Publication number: WO2020049370A1
Application number: PCT/IB2019/052943
Authority: WO
Inventors: 岩崎安希子
Original assignee: 蛇の目ミシン工業株式会社
Priority date: 2018-09-07
Filing date: 2019-04-10
Publication date: 2020-03-12
Also published as: DE112019004468B4; KR20210021033A; JP2020041839A; CN112639429A; CN112639429B; DE112019004468T5; JP7097268B2; KR102591896B1

Abstract

This invention is for simply and highly accurately estimating the lifetime of a ball screw. A device according to this invention comprises an initial load coefficient storage unit for storing a load coefficient for a ball screw, a load value detection unit, a differential value calculation unit, an average axial-direction-load-value calculation unit, an average rotation speed calculation unit, and an estimated-ball-screw-lifespan calculation unit. The load value detection unit detects values for the axial-direction load applied to the ball screw. The differential value calculation unit calculates the amount of variation in the detected axial-direction-load values. A load coefficient adjustment unit adjusts the load coefficient for the ball screw stored by the initial load coefficient storage unit on the basis of the calculated amount of load value variation. The average axial-direction-load-value calculation unit calculates an average axial-direction-load value on the basis of the detected load values. The average rotation speed calculation unit calculates the average rotation speed of the ball screw. The estimated-ball-screw-lifespan calculation unit uses the adjusted load coefficient, the calculated average axial-direction-load value, and the calculated average rotation speed of the ball screw to calculate an estimated lifespan corresponding to how the ball screw is used.

Description

Press device, terminal device, ball screw estimated life calculation method and program

The present invention relates to a press device, a terminal device, a ball screw estimated life calculation method, and a program.

2. Description of the Related Art A press device such as an electric press that applies a load by moving a ram up and down with respect to a work is known.
In this type of press device, the rotation of the motor is converted into linear motion to operate the ram up and down. A ball screw is an important mechanical component for realizing such up and down operation of the ram.
The ball screw is subjected to an impact by the load operation, so that the ball screw is deteriorated. In order to operate with an appropriate load, it is required to estimate the life as accurately as possible.

In response to such a demand, Patent Document 1 describes a means for storing in advance the relationship between the axial load of the ball screw and the motor current value, the basic dynamic load rating of the ball screw, and the sampling interval and time. Means for recording the amount of use of the ball screw, a coefficient of variation is measured at each sampling interval, and the rated fatigue life value calculated based on the measured value is rewritable. A ball screw life monitoring device that displays the remaining life of each ball screw is disclosed (for example, see Patent Document 1).

JP-A-5-187965

Here, in Patent Document 1, the average axial load F _m applied to the ball screw, the average rotational speed N _m of the ball _screw, on the basis of the load factor f _w is determined by the kinetic state, the estimated lifetime of the ball screw Is disclosed.

However, in general, load factor f _w is greater the larger the operation of the impact on the ball screw, the more the value is large, the estimated life time is shortened.
Further, the range of possible values of load factor _{f w} is generally 1.0 to 2.0, the standard operating _conditions, f w = 1.3, in the case of driving with shock, _{f w} = 1.8.

Here, a load _factor, the life in the case of f w = 1.8, the _{computational} becomes about 38% of the life of the case of f w = 1.3, depending determine how the load coefficient _{f w} Greatly affects the length of the estimated lifetime.
In other words, in order to prevent the ball screw from breaking earlier than expected, it is conceivable to calculate the predicted life shorter by increasing the load coefficient, but in this case, there is still room for the life of the ball screw. Despite this, the ball screw is replaced, and as a result, the ball screw and the man-hour required for the replacement may be wasted.

However, Patent Document 1, the vibration and shock "fine", "small", "medium", and divided into four "large", only load coefficient f _w are defined, above the load It cannot be said that the magnitude of the influence of the coefficient _fw on the estimated lifetime is sufficiently considered.

Further, in the technique of Patent Document 1, the estimated life time of the ball screw is obtained from the magnitude of the fluctuation of the motor current, that is, the fluctuation of the torque, but the fluctuation of the torque is more accurate than the fluctuation value of the load cell load value. In general, it is difficult to verify that the shock magnitude is clearly related to the life of the ball screw, and the verification until the ball screw actually breaks is performed in various environments and operating patterns. Since it is difficult to perform until the magnitude of the load coefficient can be clearly defined, there is a problem that the method for estimating the life time of the ball screw cannot be said to be a simple and highly accurate method.

In view of the above, the present invention has been made in view of the above-described problems, and provides a press device, a terminal device, a ball screw estimated life calculation method, and a program that easily and accurately estimate the life time of a ball screw. With the goal.

Mode 1: One or more embodiments of the present invention provide a load value detecting unit that detects an axial load value applied to a ball screw, and an average value based on the load value detected by the load value detecting unit. An average axial load value calculating unit that calculates an axial load value, an average rotational speed calculating unit that calculates an average rotational speed of the ball screw, a load coefficient of the ball screw, and the average axial load value calculating unit. Based on the calculated average axial load value and the average rotation speed of the ball screw calculated by the average rotation speed calculation unit, a press device that calculates an estimated life according to a use mode of the ball screw. A differential value calculation unit that calculates an amount of change in the axial load value detected by the load value detection unit; and a differential value calculation unit that calculates a change amount of the axial load value. Based on the amount of change in the load value, proposes a press apparatus characterized in that and a load coefficient adjusting unit that adjusts the weighting factor of the ball screw.

Mode 2; In one or more embodiments of the present invention, the load coefficient adjusted by the load coefficient adjustment unit is the average axial load value calculated by the average axial load value calculation unit, and the average rotation. The present invention proposes a press device that is calculated based on an average rotation speed of the ball screw calculated by a speed calculation unit and an actual life period of an arbitrary ball screw.

Mode 3: In one or more embodiments of the present invention, the load coefficient adjusted by the load coefficient adjustment unit may include the calculated estimated life and the actual life of the ball screw from which the estimated life is calculated. , A press apparatus characterized by being further adjusted based on the following.

Mode 4; In one or more embodiments of the present invention, the axial load value applied to the ball screw is a load value applied to the ball screw measured by a load cell, or the load value measured by the load cell. A press device is proposed, which is a sum of a load value applied to a ball screw and a load value generated by acceleration and deceleration of the ball screw when the ram moves up and down.

Mode 5: One or more embodiments of the present invention include a load value detection unit that detects an axial load value applied to a ball screw, and an average value based on the load value detected by the load value detection unit. An average axial load value calculating unit that calculates an axial load value, an average rotational speed calculating unit that calculates an average rotational speed of the ball screw, a load coefficient of the ball screw, and the average axial load value calculating unit. A calculating unit that calculates an estimated life according to a usage mode of the ball screw based on the calculated average axial load value and the average rotation speed of the ball screw calculated by the average rotation speed calculation unit. A differential value calculation unit that calculates an amount of change in the axial load value detected by the load value detection unit; and the differential value calculation unit. Based on the variation of the load value calculated Oite proposes a terminal device, characterized in that it and a load coefficient adjusting unit that adjusts the weighting factor of the ball screw.

Mode 6: One or more embodiments of the present invention include a load value detection unit that detects an axial load value applied to a ball screw, and an average value based on the load value detected by the load value detection unit. An average axial load value calculating unit that calculates an axial load value, an average rotational speed calculating unit that calculates an average rotational speed of the ball screw, a load coefficient of the ball screw, and the average axial load value calculating unit. A calculating section for calculating an average axial load value to be calculated, an average rotation speed of the ball screw calculated by the average rotation speed calculation section, and an estimated life according to a use mode of the ball screw; and a differential value calculation A ball screw estimated life calculation method in a terminal device including a unit and a load coefficient adjustment unit, wherein the differential value calculation unit detects the life of the ball screw by the load value detection unit. A first step of calculating the amount of change in the axial load value, and the load coefficient adjustment unit determines a load coefficient of the ball screw based on the amount of change in the load value calculated by the differential value calculation unit. And a second step of adjusting the estimated life of the ball screw.

Mode 7: One or more embodiments of the present invention provide a load value detecting unit that detects an axial load value applied to a ball screw, and an average value based on the load value detected by the load value detecting unit. An average axial load value calculating unit that calculates an axial load value, an average rotational speed calculating unit that calculates an average rotational speed of the ball screw, a load coefficient of the ball screw, and the average axial load value calculating unit. A calculating section for calculating an average axial load value to be calculated, an average rotation speed of the ball screw calculated by the average rotation speed calculation section, and an estimated life according to a use mode of the ball screw; and a differential value calculation A program for causing a computer to execute a method of calculating a life expectancy of a ball screw in a terminal device, the method comprising: A first step of calculating a change amount of the axial load value detected by the load value detecting section, and a load value calculated by the differential value calculating section by the load coefficient adjusting section. And a second step of adjusting the load coefficient of the ball screw based on the change amount of the ball screw.

According to one or more embodiments of the present invention, there is an effect that the life time of a ball screw can be easily and accurately estimated.

It is a figure showing the structure of the press device concerning the embodiment of the present invention.

It is a figure showing the electric composition of the press device concerning the embodiment of the present invention.

FIG. 1 is a diagram illustrating an electrical configuration of a central processing unit according to an embodiment of the present invention.

It is a figure showing how to determine a conventional load coefficient.

It is a processing flow figure concerning an embodiment of the present invention.

<Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5.

<Press device structure>
The structure of the press device 100 according to the present embodiment will be described with reference to FIG.

As shown in FIG. 1, a press device 100 according to the present embodiment includes a press ram 1 that applies a desired pressure to a work W (a processing target) by a lifting operation, and a lifting operation (a straight line) on the ram 1. ), Which are provided in the press body 3.
In addition, a servomotor 4 such as an AC servomotor serving as a driving source is also housed in a head frame of a casing 5 connected to the press body 3. The drive of the servo motor 4 is transmitted to the ball screw 2 via a pulley and a belt.

The ram 1 is formed in a cylindrical body as shown in FIG. Specifically, a hollow portion is formed along the axial direction inside a cylindrical main body 1a formed in a cylindrical shape, and the screw shaft 2a of the ball screw 2 can be inserted into the hollow portion. Has become.
A nut 2b of the ball screw 2 is fixed to an end of the cylindrical main body 1a of the ram 1 in the axial direction.

At the tip end of the tubular main body 1a, a strain-flexing column 9 is configured to be freely attachable. Actually, the strain-flexing column 9 comes into contact with the work W and appropriately applies pressure. .
The strain column 9 is configured such that a strain gauge can be attached thereto, and the strain gauge can detect a pressure applied to the workpiece W.
In addition, a similar load is applied to the ball screw moving the ram 1 as a reaction of the load applied to the workpiece W by the strain-flexing column 9.

A cylindrical guide 6 is provided so as to wrap the outer peripheral side surface of the cylindrical main body 1a.
The cylindrical guide 6 is fixed in the casing 5, and the ram 1 can move up and down along the cylindrical guide 6.

<Electrical configuration of press device>
As shown in FIG. 2, the press device 100 according to the present embodiment includes a servo motor driver 13, an encoder 14, a circuit unit 15, a drive command pulse generation unit 16, an encoder position counter 17, a control program storage unit 21, a display unit 22, an operation unit 23, a temporary storage unit 24, an initial load coefficient storage unit 25, a load value storage unit 26, a rotation speed storage unit 27, a CPU (central processing unit) 30, It is composed of

The control program storage unit 21 stores a control program for the CPU (central processing unit) 30 to control the operation and processing of the entire press apparatus 100.
For example, in the present embodiment, a program for calculating a differential value or a calculated differential value based on time-series data of a load value stored in a load value A program for calculating an adjustment amount of the load coefficient based on an initial load coefficient stored in an initial load coefficient storage unit 25 described later, and a load value stored in a load value storage unit 26 described later. A program for calculating the average axial load value, a program for calculating the average rotational speed of the ball screw based on the rotational speed of the ball screw stored in the rotational speed storage unit 27 described below, the adjusted load coefficient described above, Based on the calculated average axial load value and the average rotation speed of the ball screw, the estimated life time of the ball screw is calculated. For storing programs and the like to be out.

The display unit 22 is, for example, a display device in which a liquid crystal panel and a touch panel are stacked and various types of information are displayed.
The display unit 22 may be provided in the press device 100, or may be another device or an independent device.
In the present embodiment, for example, information such as the calculated estimated life time of the ball screw is displayed.

The operation unit 23 includes a touch panel, a tact switch, and the like for setting operation conditions and the like.

The temporary storage unit 24 includes, for example, a RAM or the like, and stores temporary data.
In the present embodiment, the basic dynamic load rating and the like are stored.

The initial load coefficient storage unit 25 stores an arbitrary load coefficient of the ball screw.
Here, the stored initial load coefficient is used as an initial value in the processing of the load coefficient adjustment unit 32 described later.

The load value storage unit 26 stores time-series data in which the pressing position of the pressing unit detected by the circuit unit 15 as the load value detecting unit or the encoder 14 is associated with the load value at the pressing position.

The rotation speed storage unit 27 calculates, for example, a rotation speed of a ball screw having a certain relationship with the motor current from a motor current obtained from a drive command pulse generated from a drive command pulse generation unit 16 described later. The rotational speed obtained by a functional block (not shown) is stored.

The circuit unit 15 as a detection unit for detecting a load amplifies a signal corresponding to a change in resistance of a strain gauge attached to the strain-giving column 9 and converts an analog signal into a digital signal by A / D conversion processing. (Central processing unit) 30.

The drive command pulse generator 16 generates a desired drive command pulse based on a command from a CPU (central processing unit) 30 and generates the drive command pulse via the CPU (central processing unit) 30. The signal is output to the servo motor driver 13.
Then, by driving the servo motor 4 under the control of the servo motor driver 13, the ram sliding mechanism 11 slides the ram 1 up and down.

The encoder 14 serving as a detecting unit for detecting the position is for detecting the rotation angle of the servomotor 4 and is used for detecting the position of the ram 1.
The information of the encoder 14 gives position information to the servo motor driver 13 for performing feedback control.
Further, the position information of the encoder 14 can be read by a CPU (Central Processing Unit) 30 via an encoder position counter 29, whereby the movement amount of the ram 1 is detected.

The CPU (central processing unit) 30 controls the operation of the entire press device 100 according to a control program stored in the control program storage unit 21. In the present embodiment, particularly, processing for estimating the life time of the ball screw is mainly performed.

<Electrical configuration of central processing unit>
As shown in FIG. 3, the central processing unit 30 according to the present embodiment includes a differential value calculation unit 31, a load coefficient adjustment unit 32, an average axial load value calculation unit 33, and an average rotation speed calculation unit 34. , A ball screw estimated life calculation unit 35.

Based on the axial load value applied to the ball screw stored in the load value storage unit 26, the differential value calculation unit 31 calculates the amount of change in the axial load value.
Here, the variation of the load value of the axial, the change amount per unit time of the load values of the axial, the load value f _m is less, as shown in Equation 1, measured by the load cell is calculated by the value of the sum of the load values f _m2 caused by acceleration and deceleration of the ball screw when the load force value f _m1 and the press ram according to the ball screw to move up and down.
Also, considering the load value due to acceleration / deceleration, in a realistic use situation (when extremely large acceleration does not continue to be applied), compared to the force f _m1 applied to the ball screw at the time of pressurization, the acceleration is applied to the ball screw. Such a load _fm2 is so small as to be negligible, but if no load is applied, the calculation result is _fm2 ≒ 0, resulting in a calculation result that the life is not infinite if no load is applied.

The greater the change in the differential value, which is the amount of change in the axial load value per unit time, the larger the instantaneous increase in the load is. Can be considered.
Here, the differential value d is a variation of the load value f _m according to the ball screw [N / S] is a unit of time is taken as t [S], the slope of the linear regression line shown in the equation (2) below It can be obtained by the formula.

In the above description, the calculation of the amount of change in the differential value per unit time has been exemplified. However, the position of the ram at the time when the i-th sampling is performed is defined as p _i [mm], and the unit is expressed by the following Expression 3. The change amount of the differential value per distance may be obtained.

The load coefficient adjustment unit 32 adjusts an arbitrary load coefficient of the ball screw stored in the initial load coefficient storage unit 25 based on the amount of change in the load value calculated by the differential value calculation unit 31.
Here, the arbitrary load coefficient is an average axial load value calculated by an average axial load value calculation unit 33 described later, an average rotation speed of the ball screw calculated by the average rotation speed calculation unit 34, and an arbitrary rotation coefficient. Based on the life time of the ball screw, the estimated life calculation unit 35 calculates the life of the ball screw.
Note that the load coefficient f _w, conventionally, as shown in FIG. 4, the vibration or shock, "fine", "small", "medium", divided into four "large", and a width And the load coefficient _fw was determined.
However, for example, the life of the ball screw when the load coefficient _fw is _fw = 1.8 is about 38% of the life of the ball screw when _fw = 1.3, so that the life of the ball screw becomes longer. In estimation, the effect is large.
Further, quantitative measurement technique has not been established with regard serves as an index for determining the load factor f _w "vibration / shock."
Therefore, in the present embodiment, in order to solve the above-described conventional problem, the differential value calculation unit 31 calculates the load coefficient adjustment unit 32 based on the ball screw initial load coefficient stored in the initial load coefficient storage unit 25. based on the amount of change in load value, using a load factor f _w adjusted for the initial weighting factors to estimate the life expectancy of the ball screw.

The average axial load value calculation unit 33 calculates the average axial load value based on the load values stored in the load value storage unit 26 that stores the load values detected by the circuit unit 15 as the load value detection unit. I do.

The average rotation speed calculator 34 calculates the average rotation speed of the ball screw.
The ball screw estimated life calculation unit 35 calculates the load coefficient adjusted by the load coefficient adjustment unit 32, the average axial load value calculated by the average axial load value calculation unit 33, and the average rotation speed calculation unit 34. Based on the average rotation speed of the ball screw, an estimated life corresponding to the usage mode of the ball screw is calculated.
Specifically, the basic dynamic load rating C [N], the load coefficient _{f w,} the average axial load value _F m [N], the average rotational speed of the ball screw and _N m ^{[min -1],} The life rotation speed L [rev] is obtained by the equation shown in Equation 4, and the estimated life time L _h [h] is obtained by the equation shown in Equation 5. Note that the average axial load value F _m [N] is obtained from Equation 6 where the rotational speed of the ball screw sampled at a constant interval at the same timing as f _mi and the sampling number is 1 and n _mi are obtained by Equation 6, and the average rotational speed is N _m [min ⁻¹ ] is obtained by Expression 7.
The obtained estimated life time is displayed on the display unit 22.
Note that the number 4, the number 5, f _w is the basic dynamic load rating C [N] and the load factor is a constant, of which, C [N] the basic dynamic load rating is used in the press apparatus 100 It depends on the type of ball screw used, and is a numerical value published by a ball screw manufacturer in a catalog or the like.
Further, the average axial load value F _m [N] and the average rotation speed N _m [min ⁻¹ ] of the ball screw are variables, and the operating environment (workpiece) of the press device 100 during sampling (simultaneously with differential sampling). (The difference in the load and the speed due to the individual difference of W).

<Processing of press machine>
In the present embodiment performs estimation life calculation of the ball screw using a load factor f _w multiple patterns simultaneously, the load coefficient f _w in fact estimated life calculation nearest ball screw and timing in broken ball screw, when the The following describes a process of making the press device 100 learn the differential value of the above, and thereby highly accurately predicting the life of the ball screw that further matches the user's unique use environment.
Specifically, when the ball screw is not corrupted is replaced, it is determined the user has determined that the optimal replacement time, the best lifetime learning close load factor f _w.
Also, if you replace the broken got a ball screw, the most life is near, and life than broken timing to learn the load coefficient f _w becomes shorter.
In the following, a case where the learning is performed in two processes of a first stage and a second stage will be described with reference to FIGS. 5 and 6.

<First stage learning process>
The first-stage learning process in the press device according to the present embodiment will be described with reference to FIG. In the first step, performing processing for the purpose of determining the approximate load factor f _w.

First, it is confirmed that the ball screw is replaced or the press is in the initial state (step S101). After replacement of the ball screw is performed in step S101 (or the initial state of the press), then the average axial load F _m and the average rotational speed N _m and a predetermined assumed value of the ball screw (for example, press the design of the device 100, the average rotational speed of the average axial load _{F m} and a ball screw is assumed as _{N m),} between a load factor _{f w} from 1.0 to 2.0, in increments of 0.1 The estimated life of the ball screw is calculated by the estimated life calculation unit 35 using the above equations (4) and (5) (step S102).

Next, the average axial load value F _m [N] calculated by the average axial load value calculation unit 33 and the average rotation speed N _m [min ⁻¹ ] of the ball screw are sampled (Step S103), and the differential value is calculated. The differential value d [N / S] calculated by the calculator 31 is sampled (step S104).

In step S103, the estimated life of the ball screw is calculated using the sampled average axial load value F _m [N], the average rotation speed N _m [min ⁻¹ ] of the ball screw, and the above equations (4) and (5). The calculation unit 35 recalculates the estimated life of the ball screw (step S105).

Thereafter, the user determines whether the ball screw is actually broken (step S106). If it is determined in step S106 that the ball screw is broken by the user ("YES" in step S106), the calculated estimated life time is the longest among the calculated estimated life times shorter than the actual life time. learns the load factor f _w corresponding to the time as a true value (step S108), in step S104, and calculates the time average value of the sampled differential value d (step S110), and ends the learning processing in the first stage .

On the other hand, if it is determined in step S106 that the ball screw is not broken by the user ("NO" in step S106), the ball screw is not broken but has deteriorated and needs to be replaced. The user determines whether or not it is not necessary (step S107). If the user determines that the ball screw need not be replaced ("NO" in step S107), the process returns to step S103.

When the user determines in step S107 that the ball screw needs to be replaced (“YES” in step S107), the time when the determination is made is regarded as the actual life time, and the actual life time of the ball screw is determined. learning closest load factor _{f w} as a true value (step S109), in step S104, and calculates the time average value of the sampled differential value d (step S110), and ends the learning processing in the first stage.

<Learning process of second stage>
With reference to FIG. 6, a description will be given of a second-stage learning process in the press device according to the present embodiment.
In the second stage, the load coefficient f _w learned in the first stage as the initial value, is increased accuracy finely adjusted more load coefficient f _w therefrom.

First, the user determines whether or not the environment of the ball screw has changed significantly (for example, the work W has been changed to a completely different one, etc.) as compared with the time of the first-stage learning process (step S201).
At this time, if the user determines that the environment of the ball screw has changed significantly ("YES" in step S201), the second stage is terminated and learning is restarted from the first stage.

On the other hand, when the user determines that the environment of the ball screw has not changed significantly (“NO” in step S201), the user replaces the ball screw (step S202), and at regular time intervals, the average axial direction is changed. A time average value of the load value, the average rotation speed of the ball screw, and the differential value d is obtained (step S203).
The replacement of the ball screw is performed by using a ball screw whose specifications and the like do not differ before and after the replacement.

Next, the CPU (central processing unit) 30 compares the time average value of the differential value d acquired in step S203 with the time average value of the differential value d acquired in step S110 of the first stage (step S204). ).

As a result of the comparison, the CPU (central processing unit) 30 determines that the time average of the differential value d obtained in step S203 is larger than the time average of the differential value d obtained in step S110 of the first stage. case ( "YES" in step S204), it is determined to have been subjected to high operating shock than in the first stage, by changing the load factor f _w to a value smaller than the previous load coefficient f _w (Step S206), the process proceeds to Step S207.
In the step S206, for example, to reduce by 0.1 intervals than the previous load factor _{f w} Load Factor _{f w.}

On the other hand, as a result of the comparison, the CPU (central processing unit) 30 determines that the time average value of the differential value d obtained in step S203 is smaller than the time average value of the differential value d obtained in step S110 of the first stage. If it is determined that the ( "NO" in step S204), it is determined to have been subjected to less operating shock than in the first stage, a load factor f _w to a value greater than the previous load coefficient f _w After the change (step S205), the process proceeds to step S207.
In the step S205, for example, increased at 0.1 intervals than the previous load factor _{f w} Load Factor _{f w.}

Calculating CPU (central processing unit) 30, in step S207, to operate the ball screw life expectancy calculator 35, in step S205 or step S206, using a load factor _{f w} was changed, the estimated life time of the ball screw (Step S207).

In step S208, the user determines whether or not the ball screw has been damaged earlier than the estimated life time of the ball screw calculated in step S207, and the ball screw is sooner than the estimated life time of the ball screw calculated in step S207. If it is determined that damaged the ( "YES" in step S208), CPU (central processing unit) 30, by changing the load factor _{f w} to a value greater than the previous load coefficient _{f w} (step S210) The process returns to step S202.
In the step S210, for example, increased at 0.1 intervals than the previous load factor _{f w} Load Factor _{f w.}

On the other hand, when the user determines that the ball screw is not damaged earlier than the estimated life time of the ball screw calculated in step S207 (“NO” in step S208), the ball screw is completely damaged. However, it is determined whether or not replacement is necessary due to severe deterioration (step S209). If the user determines that replacement of the ball screw is necessary (“YES” in step S209), CPU (central processing unit) 30, by changing the load factor _{f w} to a value greater than the previous load coefficient _{f w} (step S210), the process returns to step S202.

Further, when the user determines that the ball screw need not be replaced (“NO” in step S209), the CPU (central processing unit) 30 transmits the ball screw before the ball screw needs to be replaced. It is determined whether or not the estimated life time has been reached (step S211).

If the CPU (central processing unit) 30 determines that the estimated life time of the ball screw has not been reached before the ball screw needs to be replaced (“NO” in step S211), the CPU 30 executes the processing. It returns to step S203.

On the other hand, when the CPU (central processing unit) 30 determines that the estimated life time of the ball screw has been reached before the ball screw needs to be replaced (“YES” in step S211), the CPU ( central processing unit) 30 changes the weighting factor _{f w} to a value smaller than the previous load coefficient _{f w} (step S212), the process returns to step S203.
In the step S211, for example, to reduce by 0.1 intervals than the previous load factor _{f w} Load Factor _{f w.}

As described above, the press device 100 according to the present embodiment includes an initial load coefficient storage unit 25 that stores an arbitrary load coefficient of a ball screw, and a load value that detects an axial load value applied to the ball screw. The detection unit (circuit unit 15) and the load value detection unit (circuit unit 15) calculate the amount of change in the detected load value in the axial direction, and the differential value calculation unit 31 calculates the difference. A load coefficient adjustment unit 32 that adjusts an arbitrary load coefficient of the ball screw stored in the initial load coefficient storage unit 25 based on the change amount of the load value, and a load detected by the load value detection unit (the circuit unit 15). An average axial load value calculating unit 33 for calculating an average axial load value based on the value, an average rotational speed calculating unit 34 for calculating an average rotational speed of the ball screw, and a load coefficient adjusting unit. 2, the average axial load value calculated by the average axial load value calculation unit 33, and the average rotation speed of the ball screw calculated by the average rotation speed calculation unit 34, A ball screw estimated life calculation unit 35 for calculating the estimated life according to the usage mode of the ball screw.
That is, the press device according to the present embodiment uses the load coefficient adjustment unit 32 to determine the load coefficient that has the greatest effect on the accuracy of the estimated ball screw life time calculated by the estimated ball screw life calculation unit 35 in the differential value calculation unit 31. The estimated life time of the ball screw is calculated using a value obtained by adjusting an arbitrary load coefficient of the ball screw stored in the initial load coefficient storage unit 25 based on the calculated amount of change in the load value.
From this, it becomes possible to more accurately adjust the load coefficient stored in advance using the differential value (the amount of change in the load value). Specifically, the load coefficient is increased or decreased by comparing a differential value in a certain usage method with a differential value in another usage method. According to this method, when the use of the ball screw changes, it is possible to obtain the load coefficient according to the use mode. Further, the estimated life of the ball screw according to the use mode can be calculated from the load coefficient.
Therefore, the life time of the ball screw can be easily and accurately estimated.

In addition, the press device 100 according to the present embodiment calculates the average axial load value calculated by the average axial load value calculation unit 33 and the average of the ball screw calculated by the average rotation speed calculation unit 34. It is calculated based on the rotation speed and the life time of an arbitrary ball screw.
From this, it is possible to determine a rough load coefficient by actually using an arbitrary ball screw up to the life and comparing the life expected from the axial load value and the rotation speed with the actual life. Becomes
Using the load coefficient obtained by this method, the estimated life when a ball screw having the same type and size as those used up to that time is used in a similar usage method is roughly determined.
Therefore, the life time of the ball screw can be easily and accurately estimated.

Further, in the press device 100 according to the present embodiment, the axial load value applied to the ball screw is determined by comparing the load value applied to the ball screw measured by the load cell, or the load value applied to the ball screw measured by the load cell to the press value. And the load value generated by the acceleration and deceleration of the ball screw when the ram moves up and down.
Therefore, the value of the axial load applied to the ball screw is the load value applied to the ball screw measured by the load cell, or the load value applied to the ball screw measured by the load cell and the ball screw when the press ram moves up and down. Regarding any of the sum values with the load value caused by the acceleration and deceleration of the ball screw by comparing the differential value in one use method with the differential value in another use method, and increasing or decreasing the load coefficient, Even when the usage changes, it is possible to obtain a load coefficient according to the usage mode.
Therefore, the life time of the ball screw can be easily and accurately estimated.

Note that the processing of the press device 100 is recorded on a computer system or a computer-readable recording medium, and the program recorded on the recording medium is read and executed by the press device 100, thereby realizing the press device 100 of the present invention. can do. Here, the computer system or the computer includes an OS and hardware such as peripheral devices.

{"Computer system or computer" also includes a homepage providing environment (or display environment) if a WWW (World Wide Web) system is used. Further, the above program may be transmitted from a computer system or computer storing this program in a storage device or the like to another computer system or computer via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting a program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.

The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the computer system or the program already recorded on the computer, and what is called a difference file (difference program) may be sufficient.

As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes a design and the like without departing from the gist of the present invention.
For example, in the present embodiment, an example has been described in which the function of estimating the life of the ball screw is included as a part of the function of the press device 100. However, the present invention is not limited to this. May be provided separately from the press device 100.
Further, the server on the cloud may have the function of estimating the life of the ball screw.

Further, in the above-described embodiment, the example has been described in which the life estimation of the ball screw is mainly performed only by the unique press device 100. However, for example, the learning data can be obtained by using a plurality of the same press devices 100 at the same time. May be shared.
In this case, since a large amount of learning data can be obtained from a plurality of the same press devices 100, the learning time can be reduced.

1; Ram 1a; Cylindrical body 2; Ball screw 2a; Screw shaft 2b; Nut body 3; Press body 4; Servo motor 5; Casing 6; Cylindrical guide 9; Motor driver 14; Encoder 15; Circuit 16; Drive command pulse generator 17; Encoder position counter 21; Control program storage 22; Display 23; Operation 24; Temporary storage 25; Initial load coefficient storage 26; Value storage unit 27; rotation speed storage unit 30; CPU (Central Processing Unit)
31; differential value output unit 32; load coefficient adjustment unit 33; average axial load value calculation unit 34; average rotation speed calculation unit 35; ball screw estimated life calculation unit 100; press device W;

Claims

A load value detection unit that detects an axial load value applied to the ball screw, and an average axial load value calculation unit that calculates an average axial load value based on the load value detected by the load value detection unit, An average rotation speed calculation unit that calculates an average rotation speed of the ball screw, a load coefficient of the ball screw, an average axial load value calculated by the average axial load value calculation unit, and the average rotation speed. A press device that calculates an estimated life time according to a use mode of the ball screw, based on the average rotation speed of the ball screw calculated by a calculation unit,
A differential value calculation unit that calculates a change amount of the axial load value detected by the load value detection unit,
A load coefficient adjustment unit that adjusts a load coefficient of the ball screw based on a change amount of a load value calculated in the differential value calculation unit;
A press device comprising:
The load coefficient adjusted by the load coefficient adjustment unit is:
The average axial load value calculated by the average axial load value calculation unit, the average rotation speed of the ball screw calculated by the average rotation speed calculation unit, and the actual life time of any ball screw. The press apparatus according to claim 1, wherein the press apparatus is calculated based on the information.
The load coefficient adjusted in the load coefficient adjustment unit is:
The press apparatus according to claim 1, wherein adjustment is further made based on the calculated estimated life time and an actual life time of the ball screw for which the estimated life time is calculated.
The axial load value applied to the ball screw is:
The value of the load applied to the ball screw measured by the load cell, or the sum of the load value applied to the ball screw measured by the load cell and the load generated by acceleration / deceleration of the ball screw when the ram moves up and down. The press device according to any one of claims 1 to 3, wherein
A load value detection unit that detects an axial load value applied to the ball screw, and an average axial load value calculation unit that calculates an average axial load value based on the load value detected by the load value detection unit. An average rotation speed calculation unit that calculates an average rotation speed of the ball screw, a load coefficient of the ball screw, an average axial load value calculated by the average axial load value calculation unit, and the average rotation speed calculation A terminal device, comprising: a calculating unit configured to calculate an estimated life time according to a usage mode of the ball screw, based on the average rotation speed of the ball screw calculated in the unit,
A differential value calculation unit that calculates a change amount of the axial load value detected by the load value detection unit,
A load coefficient adjustment unit that adjusts a load coefficient of the ball screw based on a change amount of a load value calculated in the differential value calculation unit;
A terminal device comprising:
A load value detection unit that detects an axial load value applied to the ball screw, and an average axial load value calculation unit that calculates an average axial load value based on the load value detected by the load value detection unit. An average rotation speed calculation unit that calculates an average rotation speed of the ball screw, a load coefficient of the ball screw, an average axial load value calculated by the average axial load value calculation unit, and the average rotation speed calculation Based on the average rotation speed of the ball screw calculated in the section, based on a calculation unit that calculates an estimated life time according to the usage mode of the ball screw, a differential value calculation unit, and a load coefficient adjustment unit, A ball screw estimated life calculation method in a terminal device including:
A first step in which the differential value calculation unit calculates a change amount of the axial load value detected by the load value detection unit;
A second step of adjusting the load coefficient of the ball screw based on the amount of change in the load value calculated by the differential value calculation unit,
A ball screw estimated life calculation method characterized by comprising:
A load value detection unit that detects an axial load value applied to the ball screw, and an average axial load value calculation unit that calculates an average axial load value based on the load value detected by the load value detection unit. An average rotation speed calculation unit that calculates an average rotation speed of the ball screw, a load coefficient of the ball screw, an average axial load value calculated by the average axial load value calculation unit, and the average rotation speed calculation Based on the average rotation speed of the ball screw calculated in the section, based on a calculation unit that calculates an estimated life time according to the usage mode of the ball screw, a differential value calculation unit, and a load coefficient adjustment unit, A program for causing a computer to execute a ball screw estimated life calculation method in a terminal device including:
A first step in which the differential value calculation unit calculates a change amount of the axial load value detected by the load value detection unit;
A second step of adjusting the load coefficient of the ball screw based on the amount of change in the load value calculated by the differential value calculation unit,
A program for causing a computer to execute.