JP2005205503A - Tool carrying device, operation speed determining method of tool carrying device and computer program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tool carrying device capable of properly setting a revolving speed when carrying a tool by revolving motion on the basis of force acting on the tool by its revolving motion. <P>SOLUTION: A control device controls a tool magazine, and estimates centrifugal force acting on the tool (Step S1 to S3), and determines a maximum revolving speed ωmax of the tool magazine on the basis of the estimated centrifugal force and limit centrifugal force Flimit set on the basis of grip force FG of the tool in a grip arm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tool conveying device including a conveying unit for conveying a tool used by a machine tool by a turning motion, an operation speed determining method of the tool conveying device, and a computer program for controlling the tool conveying device. .

Patent Document 1 discloses a technique in which a conveying speed of an apparatus that conveys a tool used by a machine tool by a turning motion is appropriately changed according to a weight moment of the tool.
JP-A-3-60941

However, since the weight moment naturally affects the acceleration, if the transport speed is determined according to the weight moment, the optimum transport speed is not always obtained even if it has a certain degree of validity. Absent.
The present invention has been made in view of the above circumstances, and an object thereof is to appropriately set a turning speed when a tool is conveyed by a turning motion based on a force acting on the tool by the turning motion. The object is to provide a tool conveying device, an operation speed determining method for the tool conveying device, and a computer program for controlling the tool conveying device.

In order to achieve the above object, a tool transporting apparatus according to claim 1, wherein a transporting unit that transports a tool holding unit that holds a tool used by a machine tool to a predetermined position by a turning motion;
Centrifugal force estimating means for estimating the centrifugal force acting on the tool conveyed by the conveying unit;
And a speed determining means for determining a turning speed of the transport unit based on the centrifugal force estimated by the centrifugal force estimating means.
That is, if the centrifugal force acting on the tool is defined, it is possible to physically determine the maximum speed at which the tool having a predetermined mass can be turned. Therefore, the swivel speed that can be operated according to the mass of the tool is determined more appropriately.

In this case, as described in claim 2, the centrifugal force estimating means estimates the centrifugal force based on the product of the mass of the tool and the revolution radius from the rotational center of the turning motion to the center of gravity of the tool. It is good to configure. That is, if the centrifugal force acting on the tool is F, the mass of the tool is m, the center of gravity revolution radius is r, and the turning speed (angular velocity) is ω, these relationships are determined by the following equations.
F = m · r · ω ²
Therefore, by calculating m × r, it is possible to appropriately estimate the centrifugal force that acts when the tool is rotated at a predetermined turning speed.

  According to a third aspect of the present invention, the speed determining unit is configured to turn the transport unit based on the centrifugal force estimated by the centrifugal force estimating unit and the holding force with which the tool holding unit holds the tool. It is preferably arranged to determine the speed. That is, if the centrifugal force is applied to the tool beyond the holding force of the tool holding part, the tool will fall off. Therefore, if configured as in claim 3, the turning speed is maximized within the range where the tool is not dropped off. Can be determined.

  Further, as described in claim 4, the speed determining means may be configured to determine the turning speed so that the turning speed is lower than a maximum turning speed structurally allowed by the transport unit. For example, setting a speed that exceeds the limit of the turning mechanism is avoided.

  Further, in the above case, as described in claim 5, when the conveying unit is applied to a rotating tool magazine including a plurality of tool holding units positioned at an equal distance from the turning center. Well, if configured in this way, the time required for tool change can be shortened by appropriately setting the maximum turning speed of the tool magazine.

  In addition, as described in claim 6, by the transport unit, any one of a plurality of tools held in a tool magazine can be swung so as to be replaced with a tip portion of a spindle of a machine tool, In addition, a tool changer disposed between the tool magazine and the spindle may be configured. With such a configuration, the time required for tool change can be set by appropriately setting the maximum turning speed of the tool changer. Can be shortened.

  According to the present invention, since the turning speed in the transfer unit is determined based on the centrifugal force acting on the tool, the transfer speed of the tool can be appropriately improved, and the processing time by the machine tool can be shortened. It becomes.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a tool changer provided with a turret magazine will be described with reference to FIGS. In addition, the structure of the tool change apparatus in a present Example is the same as that of what is disclosed by Japanese Patent Publication No. 7-80109, for example, Below, only the part which concerns on the summary of this invention is demonstrated.

  FIG. 3A is a perspective view showing the tool magazine (conveying unit) 1 incorporated in the tool changer. In the tool magazine 1, a plurality of grip arms 3 are radially attached to the outer periphery of a generally disk-shaped magazine base 2. As shown in FIG. 4, a U-shaped holding portion (tool holding portion) 5 is formed at the distal end portion of the grip arm 3 in order to hold the upper end side of the tool holder 4 having a tool attached to the lower end side. Support pins 6 and 6 that are urged inward by a built-in coil spring (not shown) are arranged on both sides of the inner tip of the holding portion 5. And the support pins 6 and 6 are inserted in the groove | channel (not shown) provided in the tool holder 4 side, The tool holder 4 is hold | maintained here.

  The center of the magazine base 2 is coupled to the rotation shaft of the magazine motor 27 (see FIG. 5) and is driven to rotate. As shown in FIG. Inclined 18 degrees to the elevation side with respect to the horizontal. In the following, the tool and the tool holder will be regarded as one body, and hence will be referred to as the tool 4.

  FIG. 5 is a functional block diagram showing an electrical configuration of a numerical control device (centrifugal force estimating means, speed determining means) 10 for numerically controlling a machine tool including a tool changer. The numerical control device 10 is configured around a master CPU 11 that controls the entire control and a slave CPU 12 that controls work processing and tool change.

  The master CPU 11 stores a master ROM 13 for storing a program for operating the control device itself, constants, and the like, and a workpiece machining program (numerical control program) 14, and a master for temporarily storing variables, flags, etc. during control execution. The unit RAM 15 is connected. Connected to the slave CPU 12 are a slave ROM 16 for storing a motor drive program and constants for workpiece machining, and a slave RAM 17 for temporarily storing variables, flags and the like during execution of workpiece machining control.

Connected between the master CPU 11 and the slave CPU 12 is a C (Common) RAM 18 in which commands from the master CPU 11 to the slave CPU 12 or information in the opposite direction are stored. Information is written or referred to from both the master CPU 11 and the slave CPU 12 in the CRAM 18.
The master CPU 11 also has a key for creating and inputting a machining program, a start switch for starting a series of machining processes, and a manual operation that can be performed individually for confirmation of each step of the machining program. A switch unit 19 such as a switch, a keyboard 20, and a CRT (Cathode Ray Tube) 21 for displaying and referring to a processing program are connected.

  The slave CPU 12 is connected to an X-axis motor 22, a Y-axis motor 23, and a table turning motor 24 that turns the work table, and sends a control signal to these to change the work surface of the work. Further, the slave CPU 12 is connected to a vertical movement (Z-axis) motor 25 and a main shaft motor 26, and sends control signals to them, so that a predetermined tool is applied to a workpiece whose processing surface and processing position are determined. Processing according to 4 is executed.

  Further, the slave CPU 12 sends a control signal to the magazine motor 27 and the tool change motor 28 as necessary during the machining process, and executes tool change. These workpiece machining control and tool change control executed by the slave CPU 12 are executed based on instructions from the master CPU 11.

  The master CPU 11 reads the machining program 14 input from the keyboard 20 and stored in the master unit RAM 15 for each operation, and writes the machining program 14 in the CRAM 18 if it is information relating to workpiece machining. The slave CPU 12 reads the written information and executes workpiece machining control. Further, in the master unit RAM 15, data relating to the tool magazine 1 and data relating to each tool 4 set in the tool magazine 1 are also inputted and stored by the user.

FIG. 1 is a flowchart showing a flow of processing for calculating the rotation speed of the tool magazine 1 performed by the master CPU 11. This process is a process incorporated as a part of the workpiece machining program 14. First, the master CPU 11 reads the data of the mass m and the tool length L of each tool 4 set in the tool magazine 1 from the master unit RAM 15 (step S1), and then calculates the position of the center of gravity of the tool 4 (step S1). Step S2). The calculation of the center of gravity here is performed by estimating the revolution radius r of the center of gravity from the tool length L, and an approximate expression is used for the estimation. For example, if the radius from the rotation center of the magazine base 2 to the tool holding position in the grip arm 3 is r0, the center-of-gravity revolution radius r of the tool 4 is
r = r0 + L / 2 (1)
Can be approximated by

Next, the master CPU 11 calculates a centrifugal force generation condition for each tool 4 (step S3). That is, if the centrifugal force acting on the tool is F, the mass of the tool is m, the center of gravity revolution radius is r, and the turning speed is ω, these relations are determined by the following equations.
F = m · r · ω ² (2)
Therefore, by calculating the product of the mass m and the center-of-gravity revolution radius r: m × r, it is possible to appropriately estimate the centrifugal force acting when the tool is turned at a predetermined turning speed ω. Steps S1 to S3 correspond to centrifugal force estimating means. Then, among the tools, the product (m × r) max having the maximum product m × r is determined (step S4).

Subsequently, when the master CPU 11 reads the data of the grip force (holding force) FG of the tool in the grip arm 3 from the master unit RAM 15 (step S5), the master CPU 11 calculates a limit centrifugal force Flimit (step S6). The limit centrifugal force Flimit is approximately calculated by the equation (3).
Flimit = FG / sin18 ° (3)

  Here, FIG. 2A shows the lower side portion of the tool magazine 1, and FIG. 2B shows only the tool 4 whose inner axis directions coincide vertically. FIG. 2C shows the tool 4 further enlarged. In FIG. 2 (c), gravity is acting on the tool 4 held by the grip arm 3 in the vertical direction, but when the tool magazine 1 is turned, the tool 4 is inclined outward by 18 ° with respect to the vertical. Centrifugal force acts in the direction. Since a holding groove for fitting the support pin 6 is formed on the outer periphery of the tool 4, the force acting in the direction of dropping the tool 4 against the grip force of the grip arm 3 is horizontal. It becomes the force component which acts on. Therefore, the limit centrifugal force Flimit is calculated by the equation (3).

Then, the master CPU 11 calculates the maximum turning speed ωmax of the tool magazine 1 that does not exceed the limit centrifugal force Flimit by the equation (4) (step S7).
ωmax = {Flimit / (m × r) max} ^1/2 (4)
That is, the maximum turning speed ωmax is obtained by the square root of the limit centrifugal force Flimit divided by the maximum value (m × r) max of the product: m × r.

  Then, the master CPU 11 reads the turning speed ωlimit, which is the mechanical limit of the tool magazine 1, from the master unit RAM 15, and compares the magnitude relationship with the maximum turning speed ωmax (step S8). If ωmax ≦ ωlimit (“NO”), the maximum turning speed ωmax is determined as the turning speed of the tool magazine 1, and is written and stored in the master unit RAM 15 (step S9).

  Then, when the tool change of the spindle is performed in the subsequent processing of the workpiece, the slave CPU 12 holds the grip motor 3 by rotating the magazine motor 27, that is, the magazine base 2 at the maximum turning speed ωmax. Any one of the tools that have been selected is selected as an exchange target. Since the maximum turning speed ωmax determined as described above is set based on the limit centrifugal force Flimit, the tool held on the grip arm 3 is dropped even if the magazine base 2 is turned at the speed ωmax. Is definitely avoided.

  On the other hand, if ωmax> ωlimit in step S8 (“YES”), the limit turning speed ωlimit is determined as the turning speed of the tool magazine 1, and is written and stored in the master RAM 15 (step S10). That is, if the magazine base 2 is turned beyond the limit turning speed ωlimit, the mechanism may be damaged, and such a situation is avoided. Steps S7 to S10 correspond to speed determining means.

  As described above, according to the present embodiment, the control device 10 that controls the tool magazine 1 estimates the centrifugal force acting on the tool, and determines the turning speed of the tool magazine 1 based on the centrifugal force. . That is, if the centrifugal force acting on the tool 4 is defined, it is possible to physically determine the maximum speed at which the tool 4 having a predetermined mass m can be turned. Therefore, the turning speed at which the tool 4 can operate according to the mass of the tool 4 can be determined more appropriately than in the past.

  Further, the control device 10 appropriately estimates the centrifugal force acting on the tool 4 by calculating the product of the mass m of the tool 4 and the center-of-gravity revolution radius r of the tool 4 from the rotation center of the turning motion. Can do. Further, the control device 10 divides the maximum turning speed ωmax by the maximum centrifugal force Flimit set based on the gripping force FG of the tool 4 in the grip arm 3 by the maximum value (m × r) max of m × r. Since it is determined by the square root, it can be determined so that the turning speed becomes maximum within a range in which the tool 4 is not dropped from the grip arm 3.

Furthermore, since the control device 10 determines the maximum turning speed ωmax to be lower than the maximum turning speed ωlimit structurally permitted by the tool magazine 1, setting a speed exceeding the limit of the turning mechanism is avoided. The
In addition, according to the present invention, the tool magazine 1 is configured such that the tool 4 is held by the holding portion 5 at the tips of the plurality of grip arms 3 that are located at an equal distance from the turning center of the magazine base 2 and the tool 4 is turned and conveyed. By applying to the above, by appropriately setting the maximum turning speed of the tool magazine 1, it is possible to shorten the time required for tool change and improve the work efficiency.

(Second embodiment)
FIG. 6 shows a second embodiment in which the present invention is applied to a chain-type tool magazine (conveying unit) 31 in which the tool removal direction at the time of tool replacement coincides with the gravity direction (vertical direction). FIG. 3 schematically shows the configuration of 31. FIG. The tool magazine 31 is driven by a driving mechanism (not shown) disposed on the upper end side and the lower end side so that the loop of the chain 32 rotates in the vertical direction.

A plurality of holding portions (tool holding portions) 33 for holding the tool holder are arranged and fixed to the chain 32 at equal intervals, and an opening portion in which the tool holder (not shown) is attached to the holding portion 33 is formed. The chain 32 is positioned in the outer circumferential direction of the loop. The tool change is performed in a state where the holding portion 33 is positioned at the lowest point of the chain 32, and the tool holder is pulled out from the holding portion 33 in the vertical direction at the replacement position and removed. The
For the tool magazine 31 having such a configuration, when the limit centrifugal force Flimit is calculated in step S6, the calculation may be performed by adding the action of gravity to the centrifugal force acting on the tool holder as the chain 32 rotates. .

(Third embodiment)
FIG. 7 shows a third embodiment when the present invention is applied to the tool change mechanism 34 in the tool changer, and schematically shows the configuration of the tool change mechanism (conveying unit) 34. The tool change mechanism 34 is configured to rotate a turning arm 35 disposed between a tool magazine and a spindle (not shown) of the machine tool, for example, in a horizontal plane. A holding portion (tool holding portion) 36A on one end side of the swivel arm 35 holds a tool (including a holder) 37A that is used by being attached to the main shaft, and a holding portion (tool holding portion) 36B on the other end side. The tool 37B selected from the tool magazine is held for attaching to the spindle next to the tool 37A already used for machining.

  Even in the tool changing mechanism 34 having such a configuration, when the turning speed of the turning arm 35 is increased, the tool 37 held by the centrifugal force is inclined to the outside, which may hinder the tool changing. is there. Therefore, the present invention is applied, and the maximum turning speed is determined so that the inclination of the tool 37 when the turning arm 35 is turned is kept within an allowable range.

  As described above, according to the third embodiment, the present invention is a tool for replacing any one of the plurality of tools 37 held in the tool magazine by the turning arm 35 to the tip of the spindle of the machine tool. Since it is applied to the change mechanism 34, the time required for tool change can be shortened by appropriately setting the maximum turning speed of the tool changer, and the operation reliability can be improved.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following modifications or expansions are possible.
When it is assumed that there is no possibility that the maximum turning speed ωmax exceeding the mechanism limit is calculated, steps S8 and S10 may be omitted and the maximum turning speed ωmax calculated in step S7 may be always employed.

When estimating the centrifugal force acting on the tool, the center-of-gravity revolution radius r may be set to an appropriate constant value, and only the mass m of each tool may be set and estimated.
For example, the present invention may be applied to a tool magazine of a type in which tool turning is performed in a horizontal plane as disclosed in JP-A-10-263971.
Further, the present invention is not limited to those related to a machine tool, but can be applied as long as it has a mechanism for conveying a tool by a turning motion.

1 is a flowchart showing a flow of processing in which a master CPU of a numerical controller calculates a rotation speed of a tool magazine according to a first embodiment when the present invention is applied to a tool changer having a turret type magazine. (A) is a figure which shows the downward side of a tool magazine, (b) is a figure which shows only the tool in which the inner-axis direction of (a) corresponds vertically, (c) further shows the tool of (b). Enlarged illustration (A) is the perspective view which takes out and shows the tool magazine incorporated in the tool change apparatus, (b) is a side view of a tool magazine Diagram showing the tip of the grip arm Functional block diagram showing the electrical configuration of the numerical controller FIG. 4 is a diagram schematically illustrating a configuration of a tool magazine according to a second embodiment when the present invention is applied to a chain type tool magazine. FIG. 4 is a diagram schematically illustrating a configuration of a tool change mechanism according to a third embodiment when the present invention is applied to a tool change mechanism.

Explanation of symbols

  In the drawings, 1 is a tool magazine (conveying section), 3 is a grip arm, 4 is a tool, 5 is a holding section (tool holding section), 10 is a numerical control device (centrifugal force estimating means, speed determining means), and 31 is a tool. A magazine (conveying unit), 33 is a holding unit (tool holding unit), 34 is a tool changing mechanism (conveying unit), 36 is a holding unit (tool holding unit), and 37 is a tool.

Claims (14)

A transport unit that transports a tool holding unit that holds a tool used by a machine tool to a predetermined position by a turning motion;
Centrifugal force estimating means for estimating the centrifugal force acting on the tool conveyed by the conveying unit;
A tool conveying apparatus comprising: a speed determining unit that determines a turning speed of the conveying unit based on a centrifugal force estimated by the centrifugal force estimating unit.   2. The tool conveying apparatus according to claim 1, wherein the centrifugal force estimating means estimates the centrifugal force based on a product of a mass of the tool and a revolution radius from a rotation center of the turning motion to the center of gravity of the tool. .   The speed determining means determines the turning speed of the transport section based on the centrifugal force estimated by the centrifugal force estimating means and the holding force with which the tool holding section holds a tool. The tool conveying apparatus of 1 or 2.   The tool conveying apparatus according to any one of claims 1 to 3, wherein the speed determining means determines the turning speed so as to be lower than a maximum turning speed structurally allowed by the transfer unit.   The tool according to any one of claims 1 to 4, wherein the conveying unit constitutes a rotary tool magazine including a plurality of tool holding units located at an equal distance from a turning center. Conveying device.   The conveying unit is capable of turning so that any one of a plurality of tools held in a tool magazine is replaced with a tip of a spindle of a machine tool, and between the tool magazine and the spindle. The tool conveying device according to any one of claims 1 to 5, wherein the tool conveying device constitutes a tool changer disposed on the machine. A tool transporting device comprising a transporting unit that transports a tool holding unit that holds a tool used by a machine tool to a predetermined position by a swiveling motion, and a method of determining a turning speed of the transporting unit,
Estimating the centrifugal force acting on the tool transported by the transport unit,
An operation speed determination method for a tool conveying device, wherein the turning speed is determined based on an estimated centrifugal force.   8. The method for determining an operation speed of a tool conveying device according to claim 7, wherein the centrifugal force is estimated based on a product of a mass of the tool and a revolution radius from a rotation center of the turning motion to the center of gravity of the tool.   9. The operation speed determination method for a tool conveying apparatus according to claim 7, wherein the turning speed is determined based on the estimated centrifugal force and the holding force with which the tool holding unit holds the tool.   The method for determining the operation speed of the tool conveying device according to any one of claims 7 to 9, wherein the turning speed is determined so as to be lower than a maximum turning speed structurally permitted by the transfer unit. A program that is executed by a computer that controls a tool conveying device that includes a conveying unit that conveys a tool holding unit that holds a tool used by a machine tool to a predetermined position by a turning motion,
Estimating the centrifugal force acting on the tool conveyed by the conveying unit;
A computer program for determining the turning speed based on the estimated centrifugal force.   The computer program according to claim 11, wherein the centrifugal force is estimated based on a product of a mass of the tool and a revolution radius from the rotation center of the turning motion to the center of gravity of the tool.   The computer program according to claim 11 or 12, wherein the turning speed is determined based on the estimated centrifugal force and the holding force by which the tool holding unit holds the tool. The computer program according to any one of claims 11 to 13, wherein the turning speed is determined so as to be lower than a maximum turning speed structurally allowed by the transport unit.

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