JPH0615541A - Vibro-absorber for machine tool slideway used with direct-acting bearing - Google Patents

Abstract

PURPOSE:To provide a device that absorbs a fine vibration being produced when a direct-acting bearing is adopted on a slideway of a machine tool, usable for grinding and precision cutting requiring high accurateness. CONSTITUTION:An elastic body is made up of installing a lubricative resin 7 on a sliding surface of a sliding part R interposed between a slide base 1 and a mobile table 2 in the point midway between both side guide rails 4 used with a direct acting bearing 3, and any fine vibration to be produced by the direct acting bearing 3 is absorbed and controlled by applying calculated preload via the resin 7 in a downward direction, to this elastic body. With this constitution, in the case where the direct acting bearing, to which the preload is applied, is adopted to a slideway of a machine tool, it is usable for grinding and precision cutting requiring high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration absorbing device for a machine tool sliding surface using a linear motion bearing.

[0002]

2. Description of the Related Art As shown in FIG. 1, a conventional mere "flat-flat" sliding surface structure is such that a shim (adjustment plate) 10 is inserted between guide surfaces of a slide base 1a and a moving table 2a to form a sliding gap S. Since the structure is designed to operate with a clearance of several μm to several tens of μm, even if a straight line command is issued in 1 μm units by NC (numerical control), the meandering feed is within the range of “clearance amount” B
However, if the target movement in the feed direction C is not constant and the work is set on the table upper surface A and a cutting or grinding load is applied, the directionality is not fixed and 1 μ required for high precision machining.
Since it became impossible to feed a fixed amount of m to 2 μm, it affected circular arc cutting and grinding accuracy in the simultaneous biaxial control, and high accuracy such as roundness could not be obtained. 8a is a ball screw, 9
a is a servo motor.

Therefore, as a measure for improving the followability, by adopting the linear motion bearing 3a in which a preload is applied between the slide base 1a and the moving table 2a as shown in FIG. 3, the clearance of the sliding gap S in FIG. And the coefficient of friction is "V-flat"
Or, in the case of "flat-flat", it is usually 0.1 with good lubrication.
~ 0.05, but decreased to 0.03 NC
It became possible to move in the target feed direction C faithfully and accurately according to the command value of. That is, if the linear bearing can be used for the sliding surface of the machine tool, the followability is improved and the machining accuracy is improved.

Conventionally, in a grinding machine which requires high precision, a "V-flat" structure has been obliged to be adopted in order to obtain smooth sliding. However, by using a linear motion bearing, This eliminates the need for "scraping", which requires a high level of skill, leading to a reduction in manufacturing costs.

[0005]

However, a linear bearing has point contact in the case of a ball and line contact in the case of a roller, which causes minute vibrations due to its low damping capacity, which requires high precision in grinding and precision. It could not be used for turning.

Further, since the vibration generated during cutting or grinding and the vibration generated by the rotary drive portion are likely to resonate with each other, during heavy cutting or intermittent cutting, the "knocking phenomenon" damages the cutting tool, resulting in low rigidity. It has been judged. In grinding, the grindstone rotates at high speed and chatter marks are seen due to the "tapping phenomenon", and it is said that heavy grinding does not allow the desired cutting.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its gist is to provide a slide base and a moving table in the middle of both guide rails using a linear motion bearing. An elastic body is formed by providing a lubricating resin on the sliding surface of the sliding portion interposed between
Absorption of vibrations on machine tool sliding surfaces using linear bearings is characterized by absorbing and suppressing minute vibrations generated by linear bearings by applying a pre-computed downward pressure via a lubricating resin. It is a device.

Next, the present invention will be described with reference to the following embodiments with reference to FIGS.
Will be described in detail with reference to.

[0009]

[First Embodiment] First, 2 using a linear motion bearing (linear way) 3
In the middle of the guide rail 4 of the book, two L-shaped sub-slide rails 5 are fixed to the moving table 2 so as to support the moving table 2 on the upper surface of the cutting table by sandwiching the ball screw 8 and sliding base 1 A sliding part R having a structure in which two plates 6 fixed to each other are combined is provided. Therefore, an elastic body is formed by interposing a lubricating resin 7 on the sliding surface of the sliding portion R. The plate 6 is adapted to absorb and suppress the minute vibration generated by the linear motion bearing 3 by applying a calculated preload in the downward arrow direction a. Further, since a high-viscosity lubricating oil is forcibly supplied to the sliding surface of the sliding portion R to enhance the effect, rigidity is increased and high precision grinding is possible especially when the sliding table is adopted as a cutting movement table. In the figure, 9 is a servo motor. As the above-mentioned lubricating resin 7, for example, a sliding material (engineering plastic) such as trade name Turkete or Lulon is used.

[0010]

Next, the effects of the present invention will be described with reference to examples. In FIG. 6, a sliding surface (sliding surface) of the cutting table H of the CNC inner surface grinding machine (GRI-1000N2 manufactured by Taisei Machinery Co., Ltd.)
A linear motion bearing is used in the above, but the generated vibration when the vibration absorbing device of the present invention is incorporated therein and the generated vibration when the device is removed are measured positions on the cutting table H. When measured at P, the results shown in Table 1 were obtained. By the way, the maximum external (factory environment) vibration when the machine is stationary is 0.8.
There is up to μm.

[0011]

[Table 1]

From the above measurement results, adoption of the same device for the sliding portion of the inner surface grinding machine, which requires submicron processing accuracy (particularly surface roughness and straightness of tapered ground surface by simultaneous two-axis control) The utility of is fully recognized. The vibration on the cutting table affects the dynamic accuracy of the machine, but in particular, the vibration propagates to the grindstone through the grindstone spindle, and the contact of the grindstone with the work is not constant, resulting in variations in machining dimensional accuracy and a perfect circle. Every time,
Although the surface properties such as chatter marks and chatter marks are adversely affected, use of the present invention solves these problems and improves processing accuracy.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a conventional technique.

FIG. 2 is an explanatory diagram of a conventional technique.

FIG. 3 is an explanatory diagram of a conventional technique.

FIG. 4 is a front view of the device of the present invention.

FIG. 5 is a plan view of the device of the present invention.

FIG. 6 is an explanatory diagram of an example of the present invention.

[Explanation of symbols] 1 1a Slide base 2 2a Moving table 3 3a Linear motion bearing 4 Guide rail 5 Sub slide rail 6 Plate 7 Lubricating resin 8 8a Ball screw 9 9a Servo motor 10 Shim A Table top surface B Meandering feed C Purpose Feeding direction H Cutting table P Measuring position R Sliding part S Sliding gap b Arrow direction

Claims (1)

[Claims] Lubricating resin is provided on the sliding surface of the sliding part interposed between the slide base and the moving table in the middle of the guide rails on both sides using the linear motion bearing, and the elastic body is configured to face downward through the lubricating resin. A vibration absorbing device for a machine tool sliding surface using a linear motion bearing, characterized by absorbing and suppressing minute vibrations generated by the linear motion bearing by applying a preload calculated in the direction.