JPH05301136A - Guide device for machine tool - Google Patents

Abstract

PURPOSE:To improve the moving accuracy and the duration of guide sections by making stress difference small among a plural number of guide sections in a device which slidably guides a moving body along an axial line parted from the application point of force. CONSTITUTION:Paired right and left guide sections 3 and 4 are provided for the upper surface of a guide structural body 2, and a tool rest 1 is slidably guided along an axial line which is parted from the blade tip of a bite 6 acting as the application point of force. Each guide section 3 and 4 is subjected to different load in response to movement applied. Each guide section 3 and 4 is formed so that each guide section is furnished with stiffness whose magnitude is properly changed in response to applied load with the thickness of the guide section 3 close to the bite 6 thickened, and with the thickness of the guide section 4 parted from the bite 6 thinned. As a result, unbalance in stiffness for the whole of the guide sections is thereby improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide device for machine tools, and more particularly to a device for slidingly guiding a movable body such as a tool rest or a headstock along an axis away from the point of action of force. ..

[0002]

2. Description of the Related Art Generally, in a machine tool guide apparatus, it is desirable to arrange a point of action of force on a center line of a guide structure to guide a moving body in order to obtain good rigidity balance and motion accuracy. However, depending on the design conditions, the movable body may be slidably guided along the axis away from the point of action of force. In such a case, in the conventional guide device, the plurality of guide portions that support the moving body are formed to have the same size and shape as in the case where the point of action of the force is on the center line of the guide structure. For example, in a lathe as shown in FIGS. 5 and 6, a tool rest 1 as a moving body has a guide structure 2
Although it is slidably guided above, the left and right guide portions 3 and 4 are symmetrically formed with the same size and shape, even though the center line of the guide structure 2 is largely apart from the point of action of force. Was there.

[0003]

When the work 5 is cut by the cutting tool 6 in the tool rest 1, the forces acting on the cutting edge of the cutting tool 6 are, as is well known, a main component force in the Y direction and a spin force in the X direction. Although there are three components of the component force and the feed component force in the Z direction, the loads acting on the left and right guide portions 3 and 4 are different because the point of action of the force is away from the center line of the guide structure 2. Especially, in the main force component direction, the difference is the largest and becomes about 2.5 times. Here, if the guide portions 3 and 4 are formed in the same size and shape, a moment difference proportional to the load causes a stress difference of approximately 2.5 times in each of the guide portions 3 and 4.
Therefore, according to the conventional guide device, not only is it unfavorable in terms of rigidity balance, and the motion accuracy is reduced,
When the stress difference is significant, fatigue due to stress concentration shortens the life of the guide portion 3, which is a problem. Even if the left and right guide parts 3, 4 are formed in a shape on the side where a large load acts, the stress does not act evenly, and therefore, the respective guide parts 3, 4
Since there is a difference in the surface pressure at 4, it is impossible to eliminate the difference in motion accuracy.

Therefore, an object of the present invention is to reduce the stress difference between a plurality of guide portions when the movable body is slidably guided along the axis away from the point of action of force, thereby improving the accuracy of movement of the guide portions. It is to provide a guide device for a machine tool that can improve the life.

[0005]

In order to solve the above problems, the guide device of the present invention is provided with a plurality of guide portions for slidingly guiding a moving body along an axis distant from the point of action of force.
Each of the guide portions is formed so as to have rigidity according to the load that they receive.

[0006]

According to the guide device of the present invention, since the plurality of guide portions are formed so as to have rigidity according to the load, the rigidity imbalance of the entire device is improved and the stress generated in each guide portion is improved. The difference is reduced, and the motion accuracy and life are greatly improved.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment in which the present invention is embodied in a tool post of a lathe, in which 1 is a tool post and 2 is a tool post.
Is a guide structure composed of a saddle or a middle table. A pair of left and right guide parts 3 and 4 are provided on the upper surface of the guide structure 2, and the guide structure 2 extends along the axis line away from the cutting edge of the cutting tool 6, which is the point of force application. The tool post 1 is slidingly guided. Different loads act on the guide portions 3 and 4 depending on the moment, and in the illustrated example, the load in the main component force direction received by the guide portion 3 near the blade edge is 2.5 times that of the guide portion 4 far from the blade edge. .. Then, in this embodiment, the thickness of the guide portion 3 is increased, and conversely,
By reducing the wall thickness of the guide portion 4, each guide portion 3, 4
Are formed to have rigidity according to the load.

According to the above construction, since the wall thicknesses of the left and right guide portions 3 and 4 increase and decrease according to the load, the rigidity imbalance of the entire apparatus can be improved. For example, as shown in FIG. 2, the left and right guide portions 3 and 4 in the conventional device shown in FIG. 7 are increased in thickness by 5 mm on the left side and reduced by 5 mm on the right side, and the same cutting force F is applied to the cutting tool 6, Byte 6
As a result of measuring the displacement of the blade edge of the
Is 18 μm and the displacement Δ1 of the device of this embodiment is 14 μm, and the rigidity of the entire device can be improved by about 20%. Therefore, according to the guide device of the present embodiment, the difference in stress generated between the guide portions 3 and 4 can be reduced, and the motion accuracy and life can be greatly improved.

FIG. 3 shows a second embodiment in which the present invention is embodied in a tool post of a lathe. Here, the guide portions for slidably supporting the tool post 1 are a pair of left and right linear motion bearings 7, 8. It is composed of. By using the high-rigidity linear motion bearing 7 for the left guide part that receives a high load and the low-rigidity linear motion bearing 8 for the right guide part that receives a low load, each guide part is It is formed to have rigidity according to the load. Therefore, also in the guide device of the second embodiment, similarly to the first embodiment, the rigidity imbalance of the entire device is improved, the stress difference generated between the linear motion bearings 7 and 8 is reduced, and the motion accuracy and the motion accuracy are improved. The life can be improved.

FIG. 4 shows a third embodiment in which the present invention is embodied as a headstock of a lathe, in which a headstock 9 is slidably supported on a guide structure 2 and gripped by a chuck 10. The work (not shown) is configured to be cut by the cutting tool 6. A pair of left and right guide parts 3 and 4 are provided on the upper surface of the guide structure 2 to increase the wall thickness of the right guide part 4 near the cutting tool 6, which is the point of force application, and increase the thickness of the left guide part far from the cutting tool 6. By reducing the wall thickness of 3, each guide part 4,
3 is formed to have rigidity according to the load.
Therefore, according to the third embodiment, the same effects as those of the first embodiment can be obtained in the headstock 9.

The present invention is not limited to the above-mentioned embodiments. For example, by increasing or decreasing the guide area or the supply pressure of the plurality of static pressure guide portions, each guide portion is provided with rigidity according to the load. To be applied to a guide device having three or more guide parts, a tailstock of a lathe, or a guide device for a moving body in various machine tools such as a grinder. The shapes and configurations of the respective parts may be appropriately modified and embodied without departing from the spirit of the present invention.

[0012]

As described above in detail, according to the present invention, a plurality of guide portions for slidingly guiding the moving body along the axis away from the point of action of force are provided with rigidity according to the load. Since it is formed in the above, it is possible to improve the rigidity imbalance of the entire device, reduce the stress difference generated in each guide part, reduce the difference in surface pressure, and greatly improve the motion accuracy and life. Play.

[Brief description of drawings]

FIG. 1 is a front view of a tool rest showing a first embodiment of a guide device of the present invention.

FIG. 2 is a schematic view illustrating the operation of the guide device in FIG.

FIG. 3 is a front view of a tool rest showing a second embodiment of the guide device according to the present invention.

FIG. 4 is a front view of a headstock showing a third embodiment of the guide device of the present invention.

FIG. 5 is a side view showing a conventional tool rest.

FIG. 6 is a front view showing a guide device for the tool rest of FIG.

FIG. 7 is a schematic view illustrating the operation of the guide device in FIG.

[Explanation of symbols]

1 ... Turret, 2 ... Guiding structure, 3, 4 ... Guiding part,
5 ... Work, 6 ... bite, 7,8 ... Linear bearing, 9
..Spindle headstocks 10..Chucks

Claims (1)

[Claims] 1. A plurality of guide portions for slidingly guiding a moving body along an axis distant from a point of action of force are provided, and each guide portion is formed to have rigidity according to a load received by the guide portion. Characteristic machine tool guide device.