JPH0357394Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The invention relates to a machine tool equipped with a spindle head, and in particular, the spindle head is slidably attached to a cross rail that straddles two columns. Concerning gate-type or gantry-type machine tools.

(Prior Art) In general, a portal type machining center or a gantry type machining center has two columns erected on both sides of a table that is slidably placed on a bed, and two columns. The spindle head is equipped with a cross rail that is arranged to straddle the table, and a saddle that is movably attached to the cross rail in a direction perpendicular to the sliding direction of the table. is attached to the saddle so as to be movable, for example in the vertical direction.

(Problem to be solved by the invention) Conventionally, the saddle was mounted so as to be freely slidable while being suspended from the guide groove provided on the front surface of the cross rail, and the spindle head was further mounted on the front side of the saddle. has been done. Therefore, the spindle position of the spindle head is placed in a cantilevered state at a considerable distance away from the cross rail, and the larger the overhang distance from the cross rail, the more the spindle position during machining. The moment due to the reaction force (cutting thrust) acts greatly on the crossrail. Further, the spindle head is generally heavy because it is equipped with a spindle drive system, and the moment due to this weight acting on the cross rail cannot be ignored.

Therefore, in conventional gate-type or gantry-type machining centers, it is necessary to increase the rigidity of the cross rail or to strengthen the saddle mounting structure. For this reason, the cross rails, columns, etc. have become large, causing the overall size and weight of the machine tool to increase.

In addition, in machining centers, the tool magazine is generally placed independently on the outside of the column, which requires space for the tool magazine and requires a safety cover to be attached to the tool magazine. It was hot. In addition, in order to transport and exchange tools between the spindle head and tool magazine,
It was necessary to install an arm for automatic tool change.

The present invention was developed with these points in mind, and is a portal-type or gantry-type machine tool that can reduce the size and weight of cross rails and columns, as well as reduce the installation space for tool magazines. The purpose is to provide.

(Means for Solving the Problems) A machine tool according to the present invention is provided with tables that are slidably placed on a bed, each of which is erected on both sides, and at least one of which has a hollow interior. two columns in which tool magazines are disposed, and a cross rail having both ends fixed to the tops of the two columns so as to straddle the table, and having a longitudinally elongated through hole in the center. , a pair of guide rails arranged parallel to each other in the longitudinal direction with the through hole in between on the upper surface of the cross rail, and the bottom surface is engaged with the pair of guide rails with vertical movement restrained. a saddle that is slidably mounted on the pair of guide rails so as to straddle the through holes, and a spindle head that is inserted into the through holes and attached to the saddle; An inner window for tool exchange is formed on the inner side of the column where the tool magazine is arranged, and this inner window communicates with the through hole of the cross rail through the cutout window at the top. There is.

According to the present invention, since the saddle is slidably mounted and supported on two guide rails arranged parallel to each other at a predetermined interval on the upper surface of the cross rail, a moment due to overhang acts on the cross rail. The crossrail and column can be made smaller and lighter without having to do so.

In addition, the tool magazine is arranged in the cavity of the column, and the inner window provided on the inner side of the column communicates with the through hole of the cross rail via the upper notch window, so the tool magazine The installation space can be reduced and safety can be improved. Furthermore, tools can be directly replaced without the need for a special tool-exchanging arm, and operation efficiency can be improved.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is an external perspective view showing an embodiment of a machine tool according to the present invention. In the figure, reference numeral 11 is a bet, and a table 12 is placed on this bet 11.
It is mounted so as to be slidable in the axial direction. table 1
A main column 13 and a sub-column 14 are installed on both sides of 2, respectively, and these columns 13, 14
A cross rail 15 is fixed to the upper end of the table 12 so as to straddle the table 12.

As shown in FIGS. 2 and 4, the cross rail 15 has a longitudinally elongated through hole 16 in the center.
is provided. As shown in FIG. 4, the cross rail 15 has a cross-sectional structure separated into left and right sides with a through hole 16 in between. A pair of guide rails 18 are arranged parallel to each other and horizontally (in the axial direction). This guide rail 1
8 has an enlarged cross-sectional shape, for example, a circular cross-sectional shape, and is fixed to the cross rail 15 with the head protruding from the upper surface 15a of the cross rail 15.

Reference numeral 21 denotes a Y-axis feed screw, which is rotatably disposed above the guide rail 18 in parallel with the guide rail 18. Reference numeral 22 denotes a Y-axis servo motor that rotationally drives this Y-axis feed screw 21.

The saddle 23 has a through hole 1 on the guide rail 18.
It is mounted so that it can slide freely in the Y-axis direction so as to straddle 6. On the bottom surface of the saddle 23, grooves 24 are formed at positions corresponding to the pair of guide rails 18, each having a cross-sectional shape whose inner part is enlarged toward the Y-axis direction. The saddle 23 is held by engaging with the portion. A feed nut (not shown) is provided in one end of the saddle 23 facing in the Y-axis direction, and the Y-axis feed screw 21 is inserted and screwed into this feed nut.
The saddle 23 is moved along the Y axis by rotationally driving the Y axis feed screw 21.

Additionally, a saddle 23 located above the through hole 16
A vertical surface 23a is formed on the side surface of the shaft 23, perpendicular to the Y-axis, and the spindle head 26 is slidably mounted on this vertical surface 23a in the Z-axis direction. This spindle head 2
6 is moved up and down in the Z-axis direction by a Z-axis servo motor 27 attached to the upper part of the saddle 23. Further, a spindle 28 is rotatably held on the spindle head 26, and this spindle 28 is rotationally driven by a spindle motor 29 attached to the spindle head 26.

The main column 13 is hollow inside, and this cavity is used to create a storage space 31 for the tool magazine 40.
is formed. The main column 13 has at least an inner window 32 for exchanging tools with the spindle 28, and an outer window 33 for manually replenishing and exchanging tools with the tool magazine 40, and a tool magazine storage space. 31.
In particular, the inner window 32 is a cutout window 32 provided at the upper end of the main column 13 in order to allow the spindle head 26 to approach the upper position of the tool magazine 40 when exchanging tools.
It has been extended to a. Note that this cutout window 32a
is provided at a position aligned with the through hole 16 of the cross rail 15.

The tool magazine 40 includes a disc-shaped holding plate 41 that is rotatably arranged around a rotating shaft 40a that is arranged parallel to the spindle 28. A plurality of tool holding notches 42 are formed on the outer circumference of this holding plate 41.
On the other hand, a tool holder H holding a tool T is inserted and held from the horizontal direction. A motor 45 for driving tool magazine indexing is connected to the rotating shaft 40a of the holding plate 41 via a gear train 44.

Next, the operation of this embodiment having such a configuration will be explained.

To move the spindle 28 to a predetermined position, the Y-axis feed screw 21 is rotated by operating the Y-axis servo motor 22, and the saddle 23 is moved along the cross rail 15 in the Y-axis direction. This is done by operating the servo motor 27 to move the spindle head 26 up and down in the Z-axis direction. In this case, the movement of the saddle 23 in the Y-axis direction is performed by sliding on a pair of guide rails 18 arranged at a predetermined interval with the center of gravity of the saddle 23 in between. The weight of the spindle head 26 attached to the guide rail 18
The moment due to overhang does not act on the cross rail 15. Furthermore, the cutting thrust acting on the spindle 28 during machining is
It is received by the enlarged cross-sectional heads of the pair of guide rails 18 through a groove 24 formed on the bottom surface of the saddle 23, and does not act on the cross rail 15 as a moment due to overhang, as in the conventional case.

Therefore, compared to conventional gate-type machine tools in which the saddle is mounted overhanging the front side of the crossrail, the moment acting on the crossrail is extremely small, making the crossrail smaller and lighter. At the same time, the structure for mounting the saddle on the cross rail can be simplified. Furthermore, since the load on the sliding portion between the saddle and the cross rail is distributed and equalized (divided into two equal parts), frictional resistance is small and movement in the Y-axis direction is extremely smooth.

Next, when exchanging the tool T with the tool magazine 40, the tool magazine 40 is indexed and rotated at a predetermined position by the motor 45, and then the spindle head 26 is moved in the Y-axis direction. spindle 28
The center of the tool holder H is aligned with the upper axis of the tool holder H in the indexed position. At this time, the spindle head 26 passes through the through hole 16 and the cutout window 32a. Subsequently, the Z-axis servo motor 27 is operated to lower the spindle head 26, and the taper shank portion of the tool holder H is gripped by the spindle 28. Next, when the saddle 23 is moved in the Y-axis direction away from the center of the tool magazine 40, the tool holder H is moved away from the holding plate 41.
The tool T is removed from the notch 42 of the tool holder H.
The tool is exchanged and moved from the tool magazine 40 side to the spindle 28 side while being gripped by the tool magazine 40 side. spindle 2
The exchange movement from the 8 side to the tool magazine 40 side can be performed by performing an operation opposite to the above operation.

Machining using tool T is performed using spindle motor 2.
This can be done by operating 9.

As described above, according to the present embodiment, the saddle 23 to which the spindle head 26 is attached is attached to a pair of saddles 23 arranged on the upper surface of the cross rail 15 with a predetermined distance between them and the center of gravity of the saddle 23 and the spindle head 26. Since it is slidably mounted on the guide rail 18 of
The weight of the saddle 23 and the spindle head 26 acts uniformly on the cross rail 15 from above, and no moment due to overhang acts on the cross rail 15. Further, the cutting thrust during machining is also received by the enlarged cross-section head of the guide rail 18, and acts uniformly upward on the cross rail 15. Therefore, compared to the conventional saddle that is attached to the crossrail in a cantilevered manner, the crossrail does not require large rigidity, and the crossrail can be made smaller and lighter.

Further, since the tool magazine 40 is built inside the column 13, space can be saved and safety is also excellent. Furthermore, the structure is simple and does not require a special arm for tool exchange when exchanging tools.

Although this embodiment shows an example in which the tool magazine is built only inside the main column 13, it can also be built inside the sub-column 14 so that tools can be exchanged from either the left or right tool magazine. . This has the effect of increasing the number of stored tools, and also allows two sets of saddles and spindle heads to be attached to the cross rail. Further, by using a conveyance chain as the tool magazine 40 and extending it from the outer window 33 of the main column 13 to the outside of the main column 13, the number of stored tools can be increased.

Further, although the cross-sectional shapes of the guide rail 18 and the groove 24 are shown as arcuate, they may also have a dovetail shape. Alternatively, horizontal flanges may be provided at both ends of the saddle 23, and both flanges may be slidably engaged in grooves provided on opposing surfaces of both guide rails 18. In addition, the guide rail 18 and the groove 24
It is also possible to insert a ball between the two to create a linear ball guide system. In this case, since the vertical movement of the saddle 23 is restricted by the ball,
There is no need to make the head of the guide rail 18 have an enlarged cross-sectional shape, and there is no need to make the groove 24 of the saddle 23 have a cross-sectional shape whose inner part is enlarged.

Furthermore, in this embodiment, a gate-type machining center in which both columns are fixed is explained.
It can also be applied to a gantry-type machining center in which slides that move in the X-axis direction are provided under both columns.

(Effects of the invention) As explained above, according to the invention, large moments due to the weight of the saddle and spindle head or cutting thrust during machining are prevented from acting on the crossrail, and the crossrail can be made smaller and smaller. Weight reduction can be achieved.

Further, by arranging the tool magazine within the cavity of the column, the space for arranging the tool magazine can be reduced and safety can be improved.

Furthermore, since the inner window provided on the inner side of the column communicates with the through hole of the cross rail through the cutout window at the top, it is possible to perform tool exchange operations directly between the spindle head and the tool magazine. It is possible to improve the operating efficiency of machine tools.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view showing an embodiment of a machine tool according to the present invention, Fig. 2 is a sectional view taken along the line of Fig. 1, Fig. 3 is a sectional view taken along the line of Fig. 2, and Fig. 4 is a sectional view taken along the line of Fig. 2. FIG. 12...Table, 13...Main column, 15...
...Cross rail, 16...Through hole, 18...Guide rail, 23...Saddle, 24...Concave groove, 26
...Spindle head, 28...Spindle.

Claims (1)

[Claims for Utility Model Registration] Tables are placed upright on both sides of a table that is slidably placed on the bed, and at least one of them has a hollow interior, and a tool magazine is disposed within this cavity. two columns; a cross rail having both ends fixed to the tops of the two columns so as to straddle the table; and a cross rail having a longitudinally elongated through hole in the center; a pair of guide rails disposed parallel to each other in the longitudinal direction with the through hole in between; by engaging the bottom surface with the pair of guide rails with vertical movement restrained; a saddle slidably mounted on a guide rail so as to straddle the through hole; and a spindle head inserted into the through hole and attached to the saddle; A machine tool characterized in that an inner window for tool exchange is formed on the inner side of the column, and the inner window communicates with the through hole of the cross rail via an upper notch window.