JP3803693B2 - Feed guide device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a feed guide device used for a table or the like of a machine tool or the like, and more particularly to a device that suppresses the table from being lifted and tilted by the dynamic pressure of lubricating oil generated during high-speed feed.
[0002]
[Prior art]
In this type of table feeder, a flat guide surface is formed on a base, and the table is slidably guided thereon. Lubricating oil is dripped on the guided surface of the table. The table is sent on the base by an appropriate driving device.
[0003]
[Problems to be solved by the invention]
In such a conventional apparatus, when the table S is fed on the base B at a high speed as shown in FIG. 1A, the lubricating oil O is caught at the front end in the traveling direction, and the solid line in FIG. Since the dynamic pressure is generated and the movable body S is lifted and tilted by this dynamic pressure, the frictional force and the sliding resistance increase, and a large feed power is required. As a result, non-uniformity of the sliding surface contact state of the guided surface of the movable body S and fluctuations in the feed force occur. The broken line in FIG. 1B shows the distribution of pressure acting on the guided surface S1 of the movable body S during low speed feeding.
[0004]
In order to solve this, it is conceivable to narrow the width over the entire length in the longitudinal direction of the guided surface of the movable body S, but by narrowing the width over the entire length in the longitudinal direction of the guided surface, the inclination of the table increases. Deterioration in feed and machining accuracy. The coefficient of friction also increases, and abnormalities in the feed torque acting on the motor also occur, so there is a limit to reducing the width of the table.
[0005]
[Means for solving the problems]
According to the present invention, as described in claim 1, a guide surface is formed on the base, and the movable body is slidably guided by the dynamic pressure action with lubricating oil interposed on the guide surface. a guiding device comprising of, in guiding device designed to reduce the pressure receiving area of the guide surface of the movable body in order to suppress the floating of the movable body due to occurrence of dynamic pressure caused by the entrainment of lubricating oil at high feed In order to suppress the inclination of the movable body, the feed guide device is characterized in that the pressure receiving area is reduced by narrowing the width of the center portion of the guided surface of the movable body in the feed direction at both ends.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 2, a flat guide surface 2 is formed on a base 1, and a table (movable body) 3 having a guided surface 3a slidingly engaged with the flat guide surface 2 on the lower surface is shown in the horizontal direction in the figure. It is slidably guided. A lubricating oil pipe 10 is attached to the table 3, and the pipe 10 drops, for example, lubricating oil fed from the lubricating oil supply device 9 via the flexible pipe 10 a onto the guide surface 2 from the front and rear ends of the table.
[0008]
A spindle head 6 is fixed on the table 3, and a spindle 8 rotated by a motor 7 is rotatably supported on the spindle head 6. A cutting tool T is attached to the tip of the main shaft 8. The spindle head 6 is moved forward and backward in the illustrated left-right direction integrally with the table 3 by a screw feed mechanism 12 driven by the servo motor 4. When the table 3 is a rectangular slide member, the front end in the forward direction of the guided surface 3a of the table 3 entrains lubricating oil during high-speed feeding, and the dynamic pressure generated between this and the flat guide surface 2 causes the table 3 3 floats so that the front end portion in the feed direction is inclined upward, and as a result, the contact state of the slide surface is not uniform and the required power of the motor varies.
[0009]
In this invention, it is comprised so that the pressure distribution of the lubricating oil which acts on the to-be-guided surface 3a of the lower surface of the table 3 may become substantially uniform over the full length direction of a table.
In general, considering the effect of the width of the guided surface of the table on the lift, tilt, friction force, and coefficient of friction of the table, the lift decreases as the width, that is, the pressure receiving area decreases, and the tilt decreases the width of the table. As the table length is constant, the friction force increases as the table width decreases, and the friction coefficient increases rapidly.
[0010]
Accordingly, considering the lifting of the table 3, it is desired to make the width of the table 3 narrower. However, in this case, the inclination of the table 3 increases, the friction coefficient increases rapidly, and the lubricity deteriorates. Need a width.
Therefore, in the first embodiment of the present invention, as shown in FIG. 3, the guided surface 3a of the table 3 is provided with a V-shaped notch 30 from the both side portions 3L, 3R of the table to the central portion in the longitudinal direction. Thus, the width of the central portion is narrower than both end portions in the feeding direction. Preferably, the width b of the central portion is about 80% of the total width B, and the width of the notch 30 in the table longitudinal direction is about 1/3 to 1/4 of the total length L.
[0011]
When the table 3 is fed at a high speed, lubricating oil is caught between the front end portion of the guided surface 3a of the table 3 in the traveling direction and the flat guide surface 2 of the base 1, and dynamic pressure is generated therebetween. However, by forming the guided surface 3a of the table 3 in such a shape, in this embodiment, the pressure receiving area at the central portion in the longitudinal direction of the table 3 is reduced, so that the lifting force at the central portion is increased. Is smaller than that of the conventional apparatus, and the tilt and the amount of lifting of the table are suppressed.
[0012]
According to the experiment on the guide device having the guided surface shape of the table 3 described above, it was possible to reduce the lift by 5%, the inclination by 5%, and the friction force by 3% as compared with the conventional device. The table dimensions used in this experiment were 800 mm long, 135 mm wide, and 70 mm high. In this experiment, the table was sent at a speed of 30 m / min.
[0013]
As a modification of the embodiment related to the guided surface 3a of the table 3, as shown in FIG. 4 (a), both ends in the feed direction are connected by the radius of curvature R, or as shown in FIG. It is also possible to adopt a shape in which up to a straight line is connected, or a shape in which only the central portion in the longitudinal direction is connected by a single arc as shown in FIG.
In each of the above-described embodiments, the present invention is achieved by changing the pressure receiving area of the guided surface 3a of the table 3. However, according to other embodiments described below, the present invention operates on a conventional table guide. The present invention can be achieved by providing means for canceling the ridge-shaped pressure distribution at one or several places in the longitudinal direction of the table.
[0014]
FIG. 5 (a) shows an example of this solution. One or several oil grooves 15 are arranged on the guided surface 3a of the table 3 perpendicular to the feed direction. More specifically, three oil grooves 15 having a width of about 10 mm and a depth of about 5 mm are equally inserted in the guided surface 3a of the table 3 having the above dimensions.
Both ends of each oil groove 15 are opened to the atmosphere. It is desirable that the number of divisions of the guided surface 3 a by the oil groove 15 is 2 to 4 according to the size of the table 3.
[0015]
With this configuration, the pressure is released to the atmosphere in the oil groove and becomes 0, so that the dynamic pressure generated on the lower surface of the table 3 can be divided as shown in FIG. In this case, a large pressure is generated at the last part in the traveling direction. Due to this pressure (reaction force F), a rotational moment is generated in the table 3, the front in the traveling direction is pressed against the guide surface 2 of the base 1, and excessive lifting and tilting of the table 3 are suppressed.
[0016]
A function similar to this can be achieved by other than the groove. For example, a plurality of holes communicating with the atmosphere in place of the grooves 15 may be formed in the direction along the grooves 15 at the positions where the grooves 15 are formed on the guided surface 3a of the table.
In the embodiment having the groove 15 described above, the lift and inclination of the table 3 decrease with an increase in the number of divisions, and the pressure distribution in the traveling direction acting on the guided surface 3a has a reaction force at the rear end portion in the traveling direction. The distribution state is effectively generated, and the inclination of the table is suppressed.
[0017]
In each of the embodiments described above, the feed guide device of the type in which the table 3 slides on the single flat guide surface 2 is mentioned. However, the present invention can be applied only to the flat guide surface of the above-described embodiment. It is not limited. For example, a type having two guide surfaces that are separated from each other in the direction perpendicular to the feed direction, both of the two guide surfaces being flat guide surfaces, or one of the two guide surfaces being V-shaped. The present invention can also be applied to a type in which the other is a flat guide surface.
[0018]
Further, each of the pair of guide surfaces spaced apart in the direction perpendicular to the feed direction is formed in a “U” shape, and guided portions on both sides of the lower surface of the movable body are guided by the “U” shape guide surfaces. The present invention is also applicable to a type of feeding guide device.
[0019]
【The invention's effect】
According to the first aspect of the present invention, in the guide device in which the guide surface is formed on the base and the movable body is slidably guided through the lubricating oil, the guided body of the movable body is provided. By making the central part of the surface narrower than both ends and making the pressure distribution in the longitudinal direction of the guided surface acting on the guided surface substantially uniform, the floating amount and inclination of the movable body can be suppressed.
[Brief description of the drawings]
FIG. 1 is a state diagram when a movable body moves in a conventional feed guide device.
FIG. 2 is a side view of a feed guide device for a machine tool to which the present invention is applied.
FIG. 3 is a bottom view showing the shape of the guided surface of the movable body according to the first embodiment of the present invention.
FIG. 4 is a bottom view showing a modified example of the guided surface in the first embodiment.
FIGS. 5A and 5B are a side view and a bottom view of a movable body according to a second embodiment of the present invention, and an explanatory view showing a behavior of the movable body during high-speed feeding and a pressure distribution acting on a guided surface.
[Explanation of symbols]
1 Base 2 Flat guide surface 3 Table (movable body)
3a Guided surfaces 3L, 3R Table both sides 6 Spindle head 9 Lubricating oil supply device 10 Pipe 15 Oil groove 30 Notch

Claims (2)

Guided surface formed on the base, a guiding device for slidably guiding the movable member is interposed lubricant on the guide surface by the dynamic pressure effect, the entrainment of the lubricating oil at high feed In the guide device in which the pressure receiving area of the guided surface of the movable body is reduced in order to suppress the floating of the movable body due to the generation of dynamic pressure due to the dynamic pressure ,
In order to suppress the inclination of the movable body , the pressure receiving area is reduced by narrowing the width of the central portion of the guided surface of the movable body in the feeding direction at both ends. 2. The feed guide device according to claim 1, wherein a V-shaped notch is formed at both sides of the movable body in the center portion in order to make the center portion of the guided surface in the feed direction narrower than both ends. A feed guide device characterized by that.

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