JPS6186109A - Weight compensating device for main spindle head - Google Patents

Abstract

PURPOSE:To decrease the size of a machine tool itself, by a method wherein a means, which prevents production of rolling moment on a cross rail guiding a main spindle head and a column and inclination of the cross rail, is located to the weight compensating device of the main spindle head of a portal type machine tool. CONSTITUTION:In a weight compensating device, the weight of a main spindle head 18 is supported by a pair of balance beams 22 positioned facing each other with a balance therebetween, and thereby a bending force and rolling moment are prevented from being exerted on a cross rail 16. Further, both ends of the balance beam 22 are hung by means of a chain 26, and a load 28, balanced with the weight of the main spindle head 18 and its balance beam 22, is exerted on the chain 26 from the side opposite to a column 14. Thus, rolling moment produced by dint of the weight of the main spindle head 18 is prevented from being exerted on the column 14. Further, since the moving amounts of the chain 26 lifting the both ends of the balance beam 22 are coincided with each other, even if the main spindle head 18 is located in any position in a horizontal direction, a chain support part is always held in the smale level, and the cross rail 16 is inhibited against inclination.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a weight compensation device for a spindle head in a portal machine tool. , <Conventional technology> - In a gate-shaped machine tool, the axis head moves horizontally along a cross rail that spans a pair of left and right columns.
The weight of the spindle head may deform the sliding rail or column, making it impossible to achieve the required machining accuracy, and this tendency is particularly noticeable in large machine tools where the weight of the spindle head is several tens of tons.

For this reason, for example, as shown in FIG.
The cross rail 101 is pre-processed into a shape such that one guide surface 102 of the cross rail 102 is curved backward and the other guide surface 103 is curved upward.
As shown in FIG. 6, which demonstrates the principle disclosed in Japanese Patent No. 24042, a correction beam 106 is passed through a hollow cross rail 105 to which a spindle head 104 is attached, and a plurality of hollow cross rails 105 and correction beams 106 are connected to each other. It is connected by a set of push bolts 107 and pull bolts 108, and by operating these push bolts 107 and pull bolts 108, the guide surfaces 102 and 103 of the hollow cross rail 105 can be deformed as shown in FIG. Proposed.

On the other hand, a balancing device disclosed in West German Patent Publication No. 2122204 is also known, and the principle thereof is gg7
As shown in the figure, both ends of an auxiliary beam 109 that is substantially parallel to the cross rail 101 are attached via horizontal pins 110i, and the main shaft head 104 that engages with the guide surfaces 102 and 103 of the cross rail 101 and this auxiliary beam 109 are connected to each other. A vertically movable roller 112 (by a compression spring 111) is interposed in between, and the weight of the spindle head 104 is supported by an auxiliary beam 109, so that the cross rail 101 receives only the guidance of the movement of the spindle head 104 and the reaction force during processing. That's what I do.

<Problem to be solved by the invention> However, the curved guide surface 102.10 as described above
3, the amount of curvature of the guide surfaces 102 and 103 must be gradually increased as the weight of the spindle head 104 increases. Since they are in contact with each other at a constant width, the main shaft is tilted to the left or right with respect to the vertical line near the reciprocating end of the main spindle head 104.

Processing accuracy cannot be maintained. In addition, forming such curved guide surfaces 102 and 103 with high precision is very difficult, resulting in a significant increase in manufacturing costs.

On the other hand, in the case where the auxiliary beam 109 shown in FIG. At 104, a back and forth overturning moment occurs. As a result, if the guide surfaces 102 and 103 are long, the cross rail 101 will undergo torsional deformation, and the main shaft will be tilted significantly back and forth with respect to the vertical line, reducing machining accuracy. .

Furthermore, these measures are all measures against bending of the crossrail due to the weight of the spindle head, and do not take into account the influence of the spindle head on the column or the inclination of the crossrail due to the movement of the spindle axis along the crossrail. It has not been.

In other words, since the spindle head is attached to the front part of the machine tool, this causes a tipping moment that causes the column to fall forward, causing the column to tilt forward, making it difficult to obtain good straightness during vertical movement of the cross rail. There is also.

When the spindle head is located near the end of the crossrail, there is a problem in that there is a difference in the support loads between the left and right ends of the crossrail, which causes the crossrail to tilt.

Furthermore, when moving the crossrail upward, a drive device is required to bear the entire load including the spindle head, leading to an increase in its capacity.

In this way, for large-sized machining +=m, the weight of the spindle head is significantly larger than the cutting force, and this is necessary to support the weight and move the spindle head with precision.

It is necessary to provide structures such as columns and cross rails with rigidity that is several to several tens of times higher than the original rigidity that can withstand cutting force, and the drive device for this must also have a large capacity. be done.

Therefore, the entire machine tool becomes larger and heavier, which not only increases the cost of the machine tool.

Performance such as high speed and high responsiveness also deteriorated.

<Means for Solving the Problems> The present invention solves the various problems mentioned above. This prevents the cross rail from being loaded, prevents the generation of rolling moment against the column, and prevents the cross rail from tilting.

The weight of the spindle head of portal machine tools allows for the reduction in capacity of the drive device that drives the spindle head up and down, thereby reducing the size and cost of the machine tool itself and at the same time efficiently performing high-precision machining. The purpose is to provide supplementary fR mounting.

The fi-f compensator for the spindle head according to the present invention that achieves this object has a structure in which the spindle head is suspended between a pair of columns and is supported at both ends so as to be movable up and down, and the spindle head is engaged with the intermediate portion thereof. A cross rail is formed with a guide surface that guides the movement of the spindle head in the horizontal direction; a pair of balance beams parallel to each other along the balance beams; a pair of chains each connected to both ends of the balance beams to suspend the balance beams and extending to the rear surface of the columns on the opposite side of the balance beams; The present invention is characterized by comprising means for applying a load balanced with the weights of the spindle head and the balance beam to the chain on the rear surface of the column, and a connecting means for matching the movement distances of both chains.

<Function> The weight of the spindle head is supported by a pair of balance beams facing each other across the center of gravity.

No bending force or overturning moment is applied to the crossrail due to the weight of the spindle head. In addition, both ends of the balance beam that supports the weight of the spindle head are suspended by chains, and a load that balances the weight of the spindle head and its balance beam is applied to the chain from the opposite side of the column. Due to the transfer moment does not act as well as cross rail.

The driving force required to move the spindle head up and down is extremely small.

Furthermore, the chains that suspend both ends of the balance beam have the same amount of movement, so no matter where the spindle head is in the horizontal direction, the balance beam's chain support is always kept at the same height. The crossrail does not tilt as the head moves.

<Embodiments> Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a front view of a portal machine tool embodying the present invention, and FIG. 2 is a side view thereof.

As shown in FIGS. 1 and 2, a pair of parallel left and right beds 12 facing each other with a work table 11 in between is provided. The sliding column bases 13 are respectively placed on:
Columns 14 are erected perpendicularly to each of these column spaces 13, and are integrally connected to each other by a top beam 15 at the upper end of the columns 14, forming a gate-shaped frame as a whole. Both ends of a cross rail 16 are hung between both columns 14 so as to be able to slide up and down.
This cross rail 16 has a main #1 which can slide on guide surfaces 17 formed in the left and right horizontal directions on the cross rail 16.
A head 18 is attached. The spindle head 18 includes a saddle 19 that engages with the guide surface 17 of the cross rail 16 and moves in the left-right direction, and a spindle 20-? It has a ram 21 which is housed inside and is attached to the saddle 19 so as to be vertically movable.

Further, a pair of balance beams 22 parallel to the cross rail L6 are provided before and after the spindle head 18 with the center of gravity of the spindle head 18 in between.
A saddle 19 of 8 is slidably mounted and supported by a foreground haber balance beam 22 of the main frame 18.

Both ends of the balance beam 22 are connected to supports 24 via bins 23, respectively.
are respectively attached to the left and right columns 14 so as to be vertically slidable. One end of a chain 26 is connected to each support 24 via a hydraulic cylinder 25, and the balance beam 22 is connected to the hydraulic cylinder 25. It is suspended by a chain 26 via the support 24 etc., while the chain 26 is wrapped around a sprocket 27 glazed on the top beam 15 and passed over the column 14 to the balance beam 22 and the column 14 on the opposite side. A balance weight 28 is suspended from the other end of the chain 26 and extends to the back surface.

The balance weight 28 is connected to the spindle head 18 and the balance beam 2.
The weight of the chain 26 is determined so as to apply a load to the chain 26 that is balanced with the weight of the chain 26. Further, the sprocket 27 on which the left and right chains 26 are wound is connected to the shaft 29 so that the movement distances of both chains 26 are made to be the same.

Note that instead of using the balance weight 28 as a means for applying a balance load to the chain 26, a balance cylinder 30 having one end connected to the back surface of the column 14 may be used, for example, as shown in FIG. .

Further, as shown in FIG. 4 showing a hydraulic circuit diagram, a pair of pressure adjusting cams 31 are installed on the cross rail 16, the cam surfaces of which become higher as they approach the center, while the saddle 19 of the spindle head 18 is A pair of running relief valves 32 are provided corresponding to the cams 31, and their respective ronds are in contact with the cam surface of the cam 31, and the position of the ronds changes as the spindle head 18 moves. is being adjusted. These stop valves 32 are used to control the pressure of the aforementioned hydraulic cylinders 25 through the hydraulic circuit 33, and for example, when the spindle head 18 moves to the right of the cross rail 16, Then, the left driving relief valve 32 lowers the pressure of the left hydraulic cylinder 25, and
The right-hand drive relief valve 32 acts to increase the pressure of the right-hand hydraulic sill 25. As a result.

The balance of the left hydraulic cylinder 25 (the weight burden on the arm 22 is reduced, and the rotational force of the shaft 29 is generated by the balance weight 28, and that rotational force is the tensile force of the right chain 26, which has an increased weight burden. to assist.

<Effects of the Invention> As specifically explained above with reference to the embodiments, according to the present invention, bending force and transfer moment due to the weight of the spindle head act on the cross rail that guides the spindle head. This not only prevents the occurrence of a transmission moment against the column and the inclination of the crossrail due to the movement of the spindle head, but also prevents the crossrail from tilting due to the movement of the spindle head.

The drive device that drives the spindle head up and down can be made smaller in capacity.

Therefore, it is possible to provide a portal machine tool that can efficiently perform high vitreous machining while reducing the size and cost of the machine tool itself.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention. Fig. 1 is a front view of a double-column machine tool embodying the present invention, Fig. 2 of the 7th edition is a side view thereof, Fig. 3 is a side view of another embodiment, and Fig. 4 is a side view of another embodiment.
The figure is a hydraulic circuit diagram. Also. FIG. 5, FIG. 6, and FIG. 7 are conceptual diagrams each showing the principle of a conventional verbal abuse compensation device for a spindle head. Inside the drawing. 14 is a column. 16 is Crossrail. 18 is the spindle head. 22 is a balance beam. 26 is a chain. 28 is the balance way and 29 is the shaft. 30 is a balance cylinder.

Claims (1)

[Claims] A cross rail that is spanned between a pair of columns and supported at both ends so as to be able to move up and down, and in which a guide surface is formed in the middle of which the spindle head engages and guides the movement of the spindle head in the horizontal direction. , a pair of balance beams that are located front and rear across the center of gravity of the spindle head to slidably support the spindle head and are parallel to each other along the cross rail, and are connected to both ends of the balance beams, respectively. a pair of chains for suspending the balance beam and extending to the rear surface of the column opposite to the balance beam; and means for applying a load to the chain on the rear surface of the column to balance the weight of the spindle head and the balance beam. and a connecting means for matching the moving distances of both chains.