JP2002224926A - Method for correcting machining error caused by thermal displacement and machining error correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a machining error correction method with which the machining error caused by thermal displacement is corrected, and to provide a device for the correction, in a machine tool equipped with a tool change unit. SOLUTION: In a machine tool 1 equipped with tool change units 60 and 65, the device 10 for correcting the machining error caused by the thermal displacement is provided with coolant supplying means 71 and 72 for supplying coolant to a housing 55 holding a spindle 56, a coolant passage 73 formed in the housing 55. The device is also provided with tool warming means 11, 12 and 13 having flow passages 12 and 13 one end of which communicates with the coolant passage 73 formed in the housing 55, while the other end is connected to the coolant supplying means 71, and warming a next tool T held by a tool holding means 62 at a standby position. A spindle 56 and a current tool T mounted on a spindle 56 are cooled by the coolant supplied to the housing 55. The next tool T held by the tool holding means 62 is warmed by the coolant discharged from the housing 55. Hence, the current tool and the next tool have nearly same temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool magazine for holding a plurality of tools, a transfer means for transferring a next tool selected from the tools held in the tool magazine to a standby position for tool change, In a machine tool provided with a tool holding means for holding a next tool at a standby position, and a tool changing device including a change means for changing the next tool held by the tool holding means and a current tool mounted on a spindle. And a method and apparatus for correcting a processing error due to thermal displacement.

[0002]

2. Description of the Related Art FIGS. 6 and 7 show an example of a machine tool provided with the above-described tool changer. FIG. 6 is a front view showing the entire machine tool, and FIG. 7 is a side view in the direction of arrow I in FIG.

As shown in FIGS. 6 and 7, a machine tool 50 according to this embodiment is a so-called vertical machining center, and includes a bed 51, a column 52 standing on the bed 51, A spindle head 54 movably supported by a column 52, a table 53 mounted on a bed 51 below the spindle head 54, and the like are provided. The spindle head 54 is
The housing 55 includes a main shaft 56 rotatably supported by the housing 55 and the like.

A tool magazine 60 for storing a plurality of tools T is provided on the left side of the spindle head 54, and a tool changing mechanism 65 is provided at a lower end of the tool magazine 60. The tool magazine 60 includes a plurality of holding pots 62 that hold the tool T, a circular holding plate 61 that holds the holding pots 62 at regular intervals on an outer peripheral portion, and a cover 63 that surrounds the holding plates 61 and the holding pots 62. Etc. The holding plate 61 is configured to be rotationally driven by a transfer device (not shown). By rotating the holding plate 61 by this transfer device (not shown), the holding pot 6 held by the holding plate 61 is rotated.
2 as the lower opening 64 of the cover 63,
That is, it can be indexed to the indexing position. The transfer device (not shown) pivots the holding pot 62 indexed to the indexing position in a vertical plane, and stands by (parallel position) parallel to the main shaft 56.
The holding pot 62 thus transferred can be transferred to the indexing position again and returned to the original state.

The tool changing mechanism 65 includes a rotating shaft 67 disposed at an intermediate position between the holding pot 62 at the standby position and the main shaft 56 so as to be parallel to the main shaft 56.
And an exchange arm 6 fixed to the lower end of the rotating shaft 67.
And a drive means (not shown) for moving the rotating shaft 67 back and forth in the axial direction and rotating the rotating shaft 67 about the axis. The exchange arm 66 has tool holding portions at both ends thereof, and has been rotated by 90 ° about the rotation shaft 67 from the state shown in FIG. 6 before the tool exchange operation.

[0006] Then, the holding pot 62 holding a desired new tool (a tool used for the next processing, hereinafter referred to as a "next tool") T is transferred to a standby position by the transfer device (not shown). When the tool can be changed,
First, the rotating shaft 67 is rotated by 90 ° about its axis (this is defined as a positive direction), and the exchange arm 66 is rotated by 90 ° with the rotation, and as shown in FIG. The tool (hereinafter, referred to as “current tool”) T and the next tool T on the holding pot 62 side are respectively held by the tool holding portions at both ends of the exchange arm 66.

Next, when the rotary shaft 67 is advanced in the axial direction, the current tool T and the next tool T held by the exchange arm 66 are pulled out from the main shaft 56 and the holding pot 62, respectively. After T is extracted, the rotation shaft 67 is rotated 180 ° in the forward direction,
This is retracted in its axial direction. Thereby, the next tool T
Is attached to the main shaft 56, and the current tool T is held in the holding pot 62. Then, rotate the rotating shaft 67 in the opposite direction 9
After rotating by 0 ° to return to the original position, the holding pot 62 is transferred to the indexing position by the transfer device (not shown) and stored in the cover 63. As described above, the current tool T mounted on the main shaft 56 and the tool magazine 60
Is exchanged with the next tool T stored in.

By the way, the machine tool has a heat source in each part, and heat is transmitted from the heat source to each part of the machine body, and each part of the machine tool is thermally deformed. In particular, bearings that rotatably hold the main shaft generate heat due to the rolling of the rolling elements, and the generated heat expands the main shaft, thereby causing machining errors.

Therefore, conventionally, a spindle cooling device 70 as shown in FIG. 6 is provided to cool the spindle 56, to suppress the thermal expansion of the spindle 56, and to prevent the above-described machining error from occurring. As shown, the spindle cooling device 70 includes a cooling liquid supply device 71 for discharging a cooling liquid cooled to a predetermined temperature, a cooling liquid passage 73 formed in the housing 55, and one end of the cooling liquid passage 73. A supply pipe 72 connected to one end of a supply pipe 73 and the other end connected to a coolant supply device 71.
A recovery pipe 7 having one end connected to the other end of the coolant flow path 73 and the other end connected to the coolant supply device 71.
Consists of four. The cooling liquid supply device 71 includes a tank for storing the cooling liquid, a cooler for cooling the cooling liquid in the tank to a predetermined temperature, a pump for pressurizing and discharging the cooling liquid in the tank, and the like. Is formed in a spiral shape around the main shaft 56.

Thus, according to the spindle cooling device 70, the cooling liquid cooled to the predetermined temperature by the cooling liquid supply device 71 is supplied from the cooling liquid supply device 71 to the housing 55 through the supply pipe 72, The main shaft 56 is cooled by the coolant flowing through the coolant channel 73 formed in the housing 55, and the coolant having completed the cooling action is returned to the coolant supply device 71 via the recovery pipe 74 and collected. .

[0011]

However, even if the spindle 56 is cooled by using the above-described spindle cooling device 70, the elimination of the machining error has not been sufficient. That is, even if the temperature rise of the spindle 56 can be suppressed to some extent by the spindle cooling device 70,
It is impossible to do. Therefore, the temperature of the spindle 56 rises to some extent, and the heat is transferred to the tool T mounted on the spindle.
And the tool T thermally expands.

On the other hand, the next tool T held in the above-mentioned tool magazine 60 is substantially at the same temperature as room temperature.
6 has a temperature difference from the current tool T mounted on the same. That is, the current tool T mounted on the main shaft 56 is thermally expanded by the temperature difference from the next tool T held in the tool magazine 60. Therefore, a processing error occurs as a result of this difference in thermal expansion.

Further, the next tool T having a small thermal expansion is
, Heat is transmitted from the spindle 56 to the next tool T,
The next tool T undergoes thermal expansion during machining, and the machining accuracy deteriorates.

The present invention has been made in view of the above circumstances, and provides a method and a device for correcting a processing error which can correct a processing error caused by thermal displacement in a machine tool provided with a tool changing device. Aim.

[0015]

Means for Solving the Problems and Effects There is provided a tool magazine for holding a plurality of tools, and a tool magazine for holding a plurality of tools. Transfer means for transferring a next tool selected from the following to a standby position for tool change, tool holding means for holding the next tool at the standby position, and a next tool held by the tool holding means and mounted on the spindle. A method for correcting a machining error due to thermal displacement in a machine tool provided with a tool changing device configured to change a current tool with a current tool, wherein a coolant is supplied into a housing holding the spindle. Cooling the main spindle and the current tool mounted on the main spindle, and raising the temperature of the next tool held by the tool holding means by the coolant discharged from the housing. According to machining error correcting method according to thermal displacement to.

The method for correcting a machining error is described in claim 3.
This can be suitably implemented by the device invention described in (1). That is, the invention described in claim 3 is a tool magazine for holding a plurality of tools, a transfer means for transferring a next tool selected from the tools held in the tool magazine to a standby position for tool change, A tool having tool holding means for holding the next tool at the standby position, and a tool changing device including a change means for changing the next tool held by the tool holding means and the current tool mounted on the spindle; In a machine, a device for correcting a processing error due to thermal displacement, a coolant supply means for supplying coolant to a housing holding the main shaft, a coolant flow passage formed in the housing, and one end of A tool temperature raising means for communicating with a cooling liquid flow path formed in the housing, the other end of which has a flow path connected to the cooling liquid supply means, for raising the temperature of the tool held by the tool holding means; Preparation Said housing coolant from said coolant supply means, after passing through the tool temperature increase device sequentially, is adapted to be caused to reflux into the coolant supply means, the cooling liquid supplied to said housing,
A machining error due to thermal displacement, wherein the spindle and the current tool mounted on the spindle are cooled, and the temperature of the tool held by the tool holding means is increased by a coolant discharged from a housing. Related to correction device.

According to the first and third aspects of the present invention, the cooling liquid cooled to a predetermined temperature is supplied to the housing from the cooling liquid supply means, and flows through the cooling liquid flow path formed in the housing. Thereby, the main shaft is cooled.
In other words, the coolant that has passed through the housing absorbs the heat of the spindle and rises in temperature to the spindle temperature, that is, the temperature of the current tool mounted on the spindle.

The coolant discharged from the housing passes through the tool temperature raising means, and the temperature of the next tool held by the tool holding means is raised by the coolant flowing through the tool temperature raising means. That is, since the temperature of the next tool held by the tool holding means is substantially the same as the room temperature, the temperature of the next tool is increased by the cooling liquid whose temperature has been raised to substantially the same temperature as the spindle temperature. Thus, the temperature of the next tool held by the tool holding means is raised to substantially the same temperature as that of the current tool mounted on the main shaft by the coolant passing through the tool temperature raising means. As a result, the next tool held by the tool holding means thermally expands to the same degree as the current tool mounted on the main spindle, and the next tool held by the tool holding means and the next tool mounted on the main spindle as in the prior art. It is possible to prevent the occurrence of a processing error caused by a difference in thermal expansion with the current tool.

According to a second aspect of the present invention, in the method for correcting a machining error according to the first aspect, the cooling liquid discharged from the housing is passed through the tool holding means and the tool magazine. Wherein the temperature of the next tool held by the tool holding means and the tool held by the tool magazine is increased by the coolant discharged from the housing. 4. The machining error correction device according to claim 3, wherein the tool temperature raising means has one end connected to a coolant flow path formed in the housing, and the other end connected to the coolant supply means, A tool passage that passes through the tool holding means or the vicinity thereof, and the tool magazine or the vicinity thereof, and the tool holding is performed by the coolant discharged from the housing. Tool held in the stage, and the tool held in the tool magazine consisting configured to heating.

According to the second and fourth aspects of the present invention, in addition to the tool held by the tool holding means,
The temperature of the tool held in the tool magazine is also raised by the coolant discharged from the housing. If the time during which the next tool is held by the tool holding means is short, if only the temperature of the tool held by the tool holding means is raised, the temperature of the next tool is set to the same temperature as the current tool mounted on the spindle. Although it is difficult to raise the temperature of the tool in the tool magazine, it is difficult to raise the temperature of the It is possible to make the temperature almost the same as that of the current tool mounted on the.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view showing the entire machine tool provided with the machining error correction device according to the present embodiment. As shown in the figure, the machine tool 1 of the present embodiment is an improvement of the machine tool 50 according to the conventional example shown in FIGS. 6 and 7. Therefore, the same components as those of the conventional machine tool 50 are denoted by the same reference numerals,
The detailed description is omitted.

The apparatus 10 for correcting a machining error of the present embodiment is shown in FIG.
As shown in FIG. 7, a cooling liquid supply device 71 for discharging a cooling liquid cooled to a predetermined temperature, a cooling liquid passage 73 formed in the housing 55, and a holding pot 62 at the standby position.
And a supply pipe 72 having one end connected to one end of the coolant flow path 73 and the other end connected to the coolant supply device 71, and one end connected to the coolant supply device 71. A connection pipe 12 is connected to the other end of the coolant flow path 73, the other end is connected to the heating block 11, the other end is connected to the heating block 11, and the other end is connected to the coolant supply device 71. It consists of a connected collection tube 13. The heating block 1
1, the connection pipe 12 and the recovery pipe 13 correspond to a tool temperature raising means according to claim 3, and the cooling liquid supply device 71 and the supply pipe 72 correspond to a cooling liquid supply means according to claim 3.

As shown in FIG. 2, the heating block 11 has a concave portion 11a which comes into contact with the outer peripheral surface of the holding pot 62 at the standby position, and the holding pot 62 is provided with the transfer device (not shown). ), The outer peripheral surface of the holding pot 62 and the concave portion 11a are moved when it is pivoted in a vertical plane and transferred to the standby position (replacement position). It comes into contact. FIG. 2 shows the heating block 11 shown in FIG.
FIG. 3 is a plan view as viewed from above.

FIG. 3 is a sectional view taken along the line II-I in FIG.
FIG. 3 is a cross-sectional view in the direction I. As shown in the figure, a flow path 11b through which a coolant flows is formed in the temperature raising block 11, and a supply pipe 12 is connected to one end of the flow path 11b. The collection pipe 13 is connected to the end.

Thus, according to the processing error correcting device 10, first, the cooling liquid cooled to the predetermined temperature is supplied from the cooling liquid supply device 71 to the housing 55,
The main shaft 56 is cooled by the coolant flowing through the coolant channel 73 formed in the nozzle 5. In other words, the coolant that has passed through the housing 55 absorbs the heat of the main shaft 56 and
The temperature rises to a temperature substantially equal to the temperature of the tool 6, that is, the temperature of the tool T mounted on the main shaft 56.

Next, the coolant discharged from the housing 55 is supplied to the flow path 11 of the heating block 11 through the connection pipe 12.
b, and the temperature of the next tool T held in the holding pot 62 at the standby position is increased by the coolant flowing through the flow path 11b. That is, the holding pot 6
Since the temperature of the next tool T held at 2 is substantially the same as the room temperature, the temperature of the next tool T is raised by the cooling liquid whose temperature has been raised to substantially the same temperature as the temperature of the main shaft 56. Thus, the temperature of the next tool T held in the holding pot 62 is raised to substantially the same temperature as the current tool T mounted on the main shaft 56 by the coolant flowing through the temperature raising block 11. This allows
The next tool T held in the holding pot 62 is
, The thermal expansion to the same extent as that of the current tool T mounted on the second tool T, and the occurrence of a processing error due to the difference in thermal expansion between the next tool T and the current tool T as in the related art can be prevented.

The coolant flowing through the heating block 11 is returned to the coolant supply device 71 via the recovery pipe 13 and is recovered.

As described above, one embodiment of the present invention has been described. However, specific embodiments that the present invention can take are not limited thereto. For example, in the above example, after the holding pot 62 is indexed to the indexing position, the holding pot 62 is configured to be moved to a standby position (exchange position) by turning in a vertical plane. Not limited to this, a holding pot different from the holding pot 62 constituting the tool magazine 60 is fixed and arranged at the standby position, and the next tool T is transferred from the tool magazine 60 to the holding pot at the standby position by an appropriate transfer device. It may be configured. Also, in this case,
Without providing the temperature raising block 11, the flow path 11b may be formed in the holding pot at the standby position, and the connection pipe 12 and the recovery pipe 13 may be connected to the flow path 11b.

Further, the present invention can have the embodiments shown in FIGS. As shown, this machine tool 2
0 indicates that the coolant passage 21 is formed in the holding plate 61 of the machine tool 1 according to the above-described embodiment, and that the collection pipe 1
This is a modification of the route 3. The flow path 21 includes a flow path from the center of the holding plate 61 to the periphery, a flow path formed in an arc shape along the periphery, and a flow path from the periphery to the center. A connection pipe 22 having the other end connected to the heating block 11 is connected to the flow path 21. The collection pipe 13 is connected to the flow path 21.

According to the machine tool 20, the coolant flowing out of the heating block 11 flows into the flow path 21 of the holding plate 61 via the connection pipe 22, and flows through the flow path 21. It flows out of the holding plate 61, is returned to the cooling liquid supply device 71 via the recovery pipe 13, and is recovered.

Then, the temperature of the holding plate 61 is raised by the coolant flowing through the flow path 21 of the holding plate 61, and the holding pot 62 connected to the holding plate 61 and the tool T held thereby are mounted on the main shaft 56. The temperature is raised to substantially the same temperature as the current tool T that has been set. If the time during which the next tool is held in the holding pot 62 at the standby position is short,
If only the tool held in the holding pot 62 at the standby position is heated, it is difficult to raise the temperature of this tool to the same temperature as the current tool T mounted on the main shaft 56. According to this example, since the temperature of the tool T held in the tool magazine 60 can be increased, even if the time held in the holding pot 62 at the standby position is short, the next tool T The temperature can be substantially the same as the temperature of the current tool T mounted on the main shaft 56, and more precisely, a processing error due to a difference in thermal expansion can be prevented.

[Brief description of the drawings]

FIG. 1 is a front view showing an entire machine tool provided with a machining error correction device according to an embodiment of the present invention.

FIG. 2 is a plan view of the heating block shown in FIG. 1 as viewed from above.

FIG. 3 is a sectional view taken in the direction of arrows II-II in FIG. 2;

FIG. 4 is a front view showing an entire machine tool provided with a machining error correction device according to another embodiment of the present invention.

FIG. 5 is a side view in the direction of arrow III in FIG. 4;

FIG. 6 is a front view showing an entire machine tool according to a conventional example.

FIG. 7 is a side view in the direction of arrow I in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Machine tool 10 Processing error correction apparatus 11 Heating block 12 Connection pipe 13 Recovery pipe 55 Housing 56 Main shaft 62 Holding pot 71 Coolant supply device 72 Supply pipe 73 Coolant flow path

Claims (4)

[Claims] A tool magazine for holding a plurality of tools, a transfer means for transferring a next tool selected from tools held in the tool magazine to a standby position for tool change,
A tool having tool holding means for holding the next tool at the standby position, and a tool changing device including a change means for changing the next tool held by the tool holding means and the current tool mounted on the spindle; In a machine, a method for correcting a processing error due to thermal displacement, supplying a coolant to a housing holding the spindle,
The thermal displacement characterized by cooling the spindle and the current tool mounted on the spindle, and raising the temperature of the next tool held by the tool holding means by the coolant discharged from the housing. Processing error correction method. 2. The following tool, wherein the coolant discharged from the housing is passed through the tool holding means and the tool magazine, and the next tool held by the tool holding means by the coolant discharged from the housing. 2. The method according to claim 1, wherein the temperature of the tool held in the magazine is increased. 3. A tool magazine for holding a plurality of tools, transfer means for transferring a next tool selected from tools held in the tool magazine to a standby position for tool change,
A tool having tool holding means for holding the next tool at the standby position, and a tool changing device including a change means for changing the next tool held by the tool holding means and the current tool mounted on the spindle; A machine for correcting a machining error due to thermal displacement, a coolant supply means for supplying coolant to a housing holding the main shaft, a coolant flow passage formed in the housing, A tool temperature raising means for communicating with a cooling liquid flow path formed in the housing, the other end of which has a flow path connected to the cooling liquid supply means, for raising the temperature of the tool held by the tool holding means; The cooling liquid is supplied from the cooling liquid supply means to the cooling liquid supply means after passing through the housing and the tool temperature raising means in this order. Thus, the main spindle and the current tool mounted on the main spindle are cooled, and the temperature of the tool held by the tool holding means is increased by the coolant discharged from the housing. Processing error correction device. 4. The tool temperature raising means has one end connected to a coolant flow path formed in the housing, the other end connected to the coolant supply means, and the tool holding means or the vicinity thereof. And a flow path passing through the tool magazine or in the vicinity thereof, and the temperature of the tool held by the tool holding means and the tool held by the tool magazine are raised by the coolant discharged from the housing. 4. The apparatus according to claim 3, wherein said apparatus is configured to correct a processing error caused by thermal displacement.