JP2012106292A - Apparatus and method for feeding coolant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for feeding a coolant, which eliminates the need of installment of a pressure detector in a coolant route path, enables early detection of such failures as a clogging with a coolant and wear of a pump and can feed a coolant effectively, and to provide a method for feeding a coolant.SOLUTION: The apparatus 20 for feeding a coolant includes: a pump 23 that is communicated with a feeding hole 17a at a base end of a blade tool 17 via a main shaft 15 and feeds a coolant to the blade tool 17; a motor 22 for driving the pump 23; and a controller 21 for controlling the rotation number of the motor 22. The controller 21 stores preset rotation numbers Ra-Rd of the motor 22, which is preliminary determined according to a sectional area of the feeding hole 17a corresponding to kinds a-d of the blade tool 17. The controller 21 controls the rotation number of the motor 22 between the preset rotation numbers Ra-Rd according to the kinds a-d of the blade tool 17.

Description

  The present invention relates to a coolant supply apparatus and a coolant supply method, and more particularly, to a technique for improving the supply efficiency of coolant to a machine tool.

  Conventionally, in a machining machine tool, a so-called center-through coolant that supplies cutting fluid as coolant to the tip of the tool through a supply hole formed through the axial center of the tool disposed on the spindle The technique regarding is known (for example, refer patent document 1).

  Also, a technology for adjusting the coolant flow rate in a machining machine tool by arranging a pressure detector in the coolant path and controlling the pump drive based on the coolant pressure detected by the pressure detector is known. (For example, see Patent Document 2).

JP 2003-334738 A JP-A 61-109645

However, according to the configuration in which the pressure detector is arranged in the coolant path as in Patent Document 2, there is a problem that the arrangement cost of the pressure detector increases.
Further, when the coolant flow rate changes due to coolant clogging or leakage in the middle of the path, the motor rotation speed is automatically adjusted to continue processing. For this reason, there is a possibility that the clogging or leakage of the coolant is not detected as an abnormality at an early stage and the machining is continued without normalizing the coolant supply.
Furthermore, even if the supply capacity of the pump itself is reduced due to wear, etc., an abnormality cannot be detected, so the pump abnormality can be detected early by simply increasing the pump speed to compensate for the shortage of the coolant supply amount. There was a problem that it could not be discovered.

On the other hand, there is also known a technique in which a part of the coolant is discharged from the relief valve and the remaining coolant is supplied from the blade edge in order to keep the pressure constant while keeping the rotation speed of the pump constant.
Originally, in the center through coolant, the coolant is supplied through a supply hole formed through the axial center of the tool. Therefore, the required coolant flow rate and pressure are determined by the hole diameter of the supply hole. That is, it is desirable to control the flow rate and pressure of the coolant according to the hole diameter of the supply hole in the tool.
However, in the above method, there is a lot of waste when supplying the coolant, and there is a problem that the deterioration of the pump is likely to progress because it is used in a state where the rotational speed of the pump is constantly increased.

  In view of the above, the present invention eliminates the need for a pressure detector in the coolant path, makes it possible to detect abnormalities such as coolant clogging and pump wear at an early stage, and effectively supplies coolant. It is possible to provide a coolant supply device and a coolant supply method that can be performed.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, the feed hole formed through the axial center portion of the tool, which is disposed in a machine tool including a single tool selected from a plurality of types of tools as a main shaft, A coolant supply device for supplying coolant to a tip portion of a tool, the pump being in communication with a supply hole at the base end portion of the tool via the main shaft, and supplying coolant to the tool; A motor for driving the pump; and a controller for controlling the number of rotations of the motor; the controller having a motor predetermined according to a cross-sectional area of a supply hole corresponding to the type of the tool The set rotation speed is stored, and the controller controls the rotation speed of the motor to the set rotation speed in accordance with the type of the tool.

  According to a second aspect of the present invention, the controller stores in advance a set rotational speed of the motor that drives the pump so that a coolant flowing through the supply hole of the tool has a predetermined pressure. is there.

  According to a third aspect of the present invention, when the type of the tool does not store the set rotational speed of the motor, the controller controls the rotational speed of the motor to the maximum rotational speed of the pump. Is.

  According to a fourth aspect of the present invention, the supply hole formed through the shaft center portion of the tool and the spindle disposed in a machine tool having a spindle selected from a plurality of types of tools on the spindle. In the coolant supply apparatus, comprising: a pump which is communicated at a base end portion of a tool and supplies coolant to the tool; a motor which drives the pump; and a controller which controls the rotation speed of the motor. A coolant supply method for supplying coolant to the tip of the tool via the controller, wherein the controller sets a predetermined rotational speed of the motor, which is predetermined according to a cross-sectional area of the supply hole corresponding to the type of the tool. The controller controls the number of rotations of the motor to the set number of rotations according to the type of the tool.

  According to a fifth aspect of the present invention, the controller predetermines and stores a set rotational speed of the motor for driving the pump so that the coolant flowing through the supply hole of the tool has a predetermined pressure.

  According to a sixth aspect of the present invention, the controller controls the rotational speed of the motor to the maximum rotational speed of the pump when the type of tool does not store the rotational speed of the motor. .

  As effects of the present invention, the following effects can be obtained.

  According to the present invention, in the coolant supply with the center through coolant, it is not necessary to arrange the pressure detector in the coolant path, and it becomes possible to detect abnormalities such as clogging of the coolant and pump wear at an early stage, and the coolant. Can be supplied effectively.

Schematic which showed the machine tool by which the coolant supply apparatus which concerns on one Embodiment of this invention was arrange | positioned. (A) is the figure which showed the relationship between the cross-sectional area of the supply hole in a blade, and the flow volume of a coolant, (b) was the figure which showed the relationship between the flow volume of a coolant, and the rotation speed of a pump. The figure which showed the various data in each blade. The flowchart which shows a coolant supply method.

Next, embodiments of the invention will be described.
It should be noted that the technical scope of the present invention is not limited to the following examples, but broadly covers the entire scope of the technical idea that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings. It extends.

[Coolant supply device 20]
First, an outline of a coolant supply device 20 according to an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the coolant supply device 20 is disposed in a machine tool 10 such as a uniaxial NC facility or a multi-axis machining facility. The machine tool 10 includes a cutting tool 17 that is a tool such as a drill, a reamer, or a tap at the tip of the spindle 15.
The coolant supply device 20 is connected to the main shaft 15 and the coolant tank 13 through a supply pipe 19a and a supply pipe 19b, respectively. The coolant tank 13 stores the coolant that has been supplied to the blade 17 and recovered through a recovery path (not shown) so that it can be supplied again.

  And the coolant supply apparatus 20 supplies cutting fluid as coolant to the front-end | tip part of the blade 17 through the supply hole 17a formed by penetrating the axial center part of the blade 17 (what is called a center through coolant). Here, as the blade 17, a single blade 17 selected from a plurality of types of blades 17 by an ATC (Automatic Tool Changer) or the like is provided on the spindle 15.

  The coolant supply device 20 is connected to the supply hole 17 a at the base end portion of the blade 17 through the main shaft 15, and is connected to the pump 23 to drive the pump 23 by being connected to the pump 23. And a controller 21 that is connected to the motor 22 and controls the rotation speed of the motor 22. The controller 21 includes a PLC (programmable controller) and storage means (not shown), and controls the rotational speed of the motor 22 based on the set rotational speed stored in the storage means, as will be described later.

  The types of combinations of the controller 21 and the motor 22 that can be used in the present embodiment include an NC servo amplifier and a servo motor, an IPM inverter and an IPM motor, an inverter and an induction motor, and the like.

  Moreover, the pump 23 in this embodiment can adjust a flow volume by controlling the rotation speed of the motor 22, For example, positive displacement pumps, such as a gear pump, are used. Conventionally, in the cutting tool 17 that has been used at a discharge pressure of 1 MPa, the flow rate at the maximum hole diameter of the center through hole (supply hole 17a) is about 20 L / min, so the pump 23 is about 20 L / min at 1 MPa. It is desirable to have supply capability.

  In the machine tool 10 configured as described above, the coolant is supplied to the cutting tool 17 by the coolant supply device 20 when machining with the cutting tool 17 is performed. Specifically, the controller 21 that receives the instruction signal from the control device (not shown) controls the rotation speed of the motor 22 to the set rotation speed, and the motor 22 drives the pump 23 at the controlled set rotation speed. The pump 23 sucks the coolant from the coolant tank 13 through the supply pipe 19a as shown by an arrow F1 in FIG. 1, and supplies the coolant to the main shaft 15 through the supply pipe 19b as shown by the arrow F2. Then, the coolant is supplied to the distal end portion of the cutting tool 17 by flowing the coolant from the main shaft 15 into the supply hole 17a. In the present embodiment, a coolant pressure switch (not shown) is disposed on the coolant path, and if the coolant pressure reaches an upper limit (lower limit) during driving of the machine tool 10, a pressure upper limit (lower limit) signal is output. Is output to detect a pressure abnormality.

Thus, when supplying coolant to the blade 17, the diameter of the supply hole 17 a and the size of the cross-sectional area (mm ² ) are determined by the type (model) of the blade 17. As shown in FIG. 2A, the flow rate (L / min) of the coolant flowing through the supply hole 17a corresponds to the cross-sectional area of the supply hole 17a so that the inside of the supply hole 17a has a predetermined pressure. Determined. When the required coolant flow rate is determined, it is desirable that the rotational speed (rpm) of the pump 23 is determined in accordance with the required coolant flow rate as shown in FIG. That is, when the type of the blade 17 is determined, an appropriate rotation speed of the pump 23 driven by the motor 22 can be determined in advance according to the type of the blade 17.

In the present embodiment, as shown in FIGS. 2 and 3, the set rotational speed R of the motor 22 is determined in advance according to the cross-sectional area S of the supply hole 17 a corresponding to the type of the blade 17.
Specifically, as shown in FIG. 3, the hole diameters of the supply holes 17a in the types a to d of the respective cutting tools 17 are defined as Da to Dd. The cross-sectional areas Sa to Sd of the supply hole 17a are determined by the hole diameters Da to Dd of the supply hole 17a. Accordingly, as shown in FIG. 2 (a), the present applicant performs the flow rate of the coolant flowing through the supply hole 17a in each of the cross-sectional areas Sa to Sd so that the inside of the supply hole 17a becomes a predetermined pressure. It is determined as Fa to Fd based on the experimental results. Further, as shown in FIG. 2B, the set rotational speeds of the pumps 23 corresponding to the respective coolant flow rates Fa to Fd are determined as Ra to Rd based on the experimental results. That is, the set rotational speed of the pump 23 is determined in advance so that the coolant flowing through the supply hole 17a of the blade 17 has a predetermined pressure.

  In this manner, the set rotational speeds Ra to Rd of the motor 22 are determined in advance according to the cross-sectional areas Sa to Sd of the supply holes 17a corresponding to the types a to d of the cutting tool 17. Further, the storage means of the controller 21 stores the set rotational speeds Ra to Rd of the motor 22 corresponding to the types a to d of the blade 17 as shown in FIG.

  In the coolant supply device 20 configured as described above, the controller 21 controls the rotational speed of the motor 22 to the set rotational speeds Ra to Rd according to the types a to d of the blade 17. Hereinafter, a method of controlling the rotation speed of the motor 22 by the coolant supply device 20 will be specifically described with reference to FIG.

First, as shown in step S10 in FIG. 4, whether or not the cutting tool 17 selected from a plurality of types of cutting tools 17 by ATC or the like and currently mounted on the spindle 15 corresponds to the center through coolant (the supply hole 17a is provided). Whether or not it is formed).
In step S10, when it is determined that the cutting tool 17 does not correspond to the center through coolant, the process proceeds to step S30, the pump 23 is stopped, the machining is performed, and the process proceeds to step S40. In other words, the controller 21 stores the set rotational speed of the motor 22 as 0 when the cross-sectional area of the supply hole 17a corresponding to the type of the blade 17 is 0.

On the other hand, when it is determined in step S10 that the cutting tool 17 is compatible with the center through coolant, the process proceeds to step S21, and it is determined whether or not the cutting tool 17 attached to the main shaft 15 is of type a.
If it is determined in step S21 that the cutting tool 17 attached to the spindle 15 is of the type a, the process proceeds to step S31, the rotation speed of the motor 22 is controlled to the set rotation speed Ra, and the process proceeds to step S40.
In step S21, when it is determined that the cutting tool 17 mounted on the main shaft 15 is not of the type a, the process proceeds to step S22, and it is determined whether or not the cutting tool 17 mounted on the main shaft 15 is of the type b.

  Thereafter, as in the case of the blade a, in steps S22, S23, and S24, when it is determined that the blade 17 is of the types b, c, and d, the process proceeds to steps S32, S33, and S34, respectively, and the rotational speed of the motor 22 is set. Control is made to set rotational speeds Rb, Rc, and Rd, and the process proceeds to step S40.

  If it is determined in step S24 that the cutting tool 17 attached to the main shaft 15 is not of the type d, the process proceeds to step S35, and the rotational speed of the motor 22 is controlled to the maximum rotational speed of the pump 23. That is, the controller 21 controls the rotational speed of the motor 22 to the maximum rotational speed of the pump 23 when the type of the blade 17 does not store the set rotational speed of the corresponding motor 22, and the step The process proceeds to S40. Thus, even if the type of the blade 17 is not stored in the controller 21, the machine tool 10 can perform processing.

In step S40, it is determined whether or not the processing is completed. If it is determined in step S40 that the machining has not been completed, the process returns to step S10 and the machining is continued. At this time, if the amount of coolant supplied from the pump 23 exceeds the flow rate of the supply hole 17a in the blade 17, a part of the coolant is discharged from a relief valve (not shown) disposed on the path, and the coolant tank It is set as the structure returned to 13.
If it is determined in step S40 that the machining has been completed, the pump 23 is stopped to finish the machining.

In the coolant supply device 20 according to the present embodiment, the configuration as described above eliminates the need to arrange a pressure detector in the coolant path. In other words, since the coolant flow rate is adjusted in accordance with the type of the blade 17 (hole diameter of the supply hole 17a), it is necessary to detect the coolant pressure with the pressure detector in order to control the driving of the pump 23. There is no. Thereby, the arrangement cost of the pressure detector can be eliminated, and the coolant flow rate and pressure can be appropriately controlled in accordance with the diameter of the supply hole 17a in the blade 17.
In addition, the rotational speed of the pump 23 can always be maintained in an appropriate state by setting the rotational speed of the pump 23 in advance so that the coolant flowing through the supply hole 17a of the blade 17 has a predetermined pressure. Therefore, waste in supplying the coolant can be eliminated, and deterioration of the pump 23 can be made difficult to proceed.

Also, when the flow rate changes due to coolant clogging or leakage in the middle of the path, a pressure upper limit (lower limit) signal is output by a pressure switch installed on the coolant path to detect pressure abnormality It is configured as possible. For this reason, clogging or leakage of the coolant can be detected at an early stage as an abnormality, and the machining is not continued without normalizing the coolant supply.
Furthermore, when the supply capacity of the pump itself is reduced due to wear or the like, the coolant supply pressure decreases, so that it can be detected early as well, and it is possible to detect and respond to pump abnormalities at an early stage. is there.

  As described above, in the coolant supply device 20 according to the present embodiment, it is not necessary to dispose the pressure detector in the coolant path, and it becomes possible to detect abnormalities such as clogging of the coolant and wear of the pump 23 at an early stage. At the same time, the coolant can be supplied effectively.

10 Machine Tool 15 Spindle 17 Cutting Tool (Tool)
17a Supply hole 20 Coolant supply device 21 Controller 22 Motor 23 Pump

Claims (6)

Coolant is supplied to the tip of the tool through a supply hole formed through a shaft center of the tool, which is disposed in a machine tool including a single tool selected from a plurality of types of tools on the spindle. A coolant supply device for
A pump in communication with a supply hole at the base end of the tool via the main shaft to supply coolant to the tool;
A motor for driving the pump;
A controller for controlling the rotational speed of the motor,
The controller stores a preset rotational speed of the motor, which is predetermined according to the cross-sectional area of the supply hole corresponding to the type of the tool,
The controller controls the rotation speed of the motor to the set rotation speed according to the type of the tool.
A coolant supply device characterized by the above. In the controller, the set rotational speed of the motor for driving the pump is determined and stored in advance so that the coolant flowing through the supply hole of the tool has a predetermined pressure.
The coolant supply device according to claim 1, wherein: When the type of the tool does not store the set rotation speed of the motor, the controller controls the rotation speed of the motor to the maximum rotation speed of the pump.
The coolant supply device according to claim 1 or 2, wherein Arranged on a machine tool equipped with a spindle with one tool selected from multiple types of tools,
A pump that communicates with a supply hole formed through the axial center of the tool at the base end of the tool via the main shaft and supplies coolant to the tool; and a motor that drives the pump; A coolant supply device comprising: a controller for controlling the rotational speed of the motor;
A coolant supply method for supplying a coolant to the tip of the tool through the supply hole,
The controller stores a preset rotational speed of the motor, which is predetermined according to a cross-sectional area of the supply hole corresponding to the type of the tool,
The controller controls the rotation speed of the motor to the set rotation speed according to the type of the tool.
The coolant supply method characterized by the above-mentioned. The controller predetermines and stores a set rotational speed of the motor that drives the pump so that a coolant flowing through the supply hole of the tool has a predetermined pressure.
The coolant supply method according to claim 4, wherein: The controller controls the rotational speed of the motor to the maximum rotational speed of the pump when the type of tool does not store the rotational speed of the motor.
The coolant supply method according to claim 4 or 5, wherein the coolant is supplied.

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