JP2563686B2 - Sliding guide for machine tools - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding guide for machine tools.

[0002]

2. Description of the Related Art A typical example of this type is a bed for a surface grinder or a lathe. In order to slidably guide the sliding body, these beds have an oil groove 2 on the surface of the guide surface 1 and a plurality of oil supply holes 3 opened at the bottom of the oil groove 2, as shown in FIG. By forming and storing the lubricating oil supplied from these oil supply holes 3 in the oil groove 2, the guide surface 1
Lubricates the sliding surface between the and sliding body. The guide surface 1 is
It is generally finished by scraping, grinding, milling or the like. The reason is that the surface roughness of the guide surface 1 finished by these processing methods is suitable for storing the lubricating oil.

[0003]

Consider a case where the guide surface 1 is finished by lapping. 304c.
S. When a lubricating oil having a viscosity of t is used, the guide surface 1
The relationship between the coefficient of friction and the moving speed of the sliding body is shown in the graph of FIG. That is, the friction coefficient rapidly increases as the moving speed of the sliding body increases, and shows a large value of 0.5 at a speed of 40 mm / s. It is considered that the reason is that the increase in the moving speed causes the thickness of the oil film between the guide surface 1 and the sliding member to be reduced, which impairs the lubricating action, and rather causes a kind of cohesive state due to the physical properties of the lubricating oil.

Under the same conditions, when the guide surface 1 is finished by scraping, the relationship between the friction coefficient of the guide surface 1 and the moving speed of the sliding body is shown in the graph of FIG. That is, the static friction coefficient is 0.22, and as the moving speed of the sliding body increases, the friction coefficient temporarily decreases to 2
It shows a minimum value of 0.1 at a moving speed of 0 mm / s, and then the friction coefficient increases as the moving speed increases,
It is considered that the lubricant is in a mixed state in the moving speed range of 3 to 20 mm / s, and stick slip (adhesion slip) is more likely to occur when the feed rigidity of the sliding body is low.

Next, when the viscosity is 304 c. S. Using the lubricating oil of t, the sliding body is reciprocated with a cycle time of about 2 seconds,
The graph of FIG. 10 shows the relationship between the floating amount of the sliding body, the friction coefficient of the guiding surface 1, and the moving speed of the sliding body when the moving direction is reversed. That is, the friction coefficient tends to decrease until the moving speed of the sliding body reaches 40 mm / s, and the friction coefficient increases when the moving speed becomes higher than that. Further, since the flatness of the lapping surface is 1 μm or less, the floating amount of the sliding body with respect to the guide surface 1 when the moving direction of the sliding body is reversed is as small as 2 μm even when the moving speed is 100 mm / s. I understand.

Under the same conditions, the relationship between the floating amount of the sliding body, the friction coefficient, and the moving speed of the sliding body with respect to the guide surface 1 finished by scraping is shown in the graph of FIG. The friction coefficient has a minimum value of 0.08 when the moving speed of the sliding body is 18 mm / s, and then tends to increase linearly as the moving speed of the sliding body increases. On the other hand, the floating amount of the slide body with respect to the guide surface 1 rapidly increases as the moving speed of the slide body increases, and is 100 mm / s.
When it reaches the moving speed of, it shows a large value of 8 μm.

[0007]

[Table 1]

Here, as shown in Table 1, the types of the finishing surface of the guide surface are set to wrapping and scraping (10bearin), respectively.
g), scraper (20bearing), grinder (cup grindstone grinding), milling, etc. are classified according to the processing methods. Samples 4 as shown in FIGS. Measure the penetration rate of the lubricating oil. That is, an oil groove 2 for storing lubricating oil and an oil supply hole 3 are formed on the finishing surface 5, an optical flat is brought into contact with the finishing surface 5, and the lubricating oil is injected from the oil supply hole 3 to finish the lubricating oil. Take a picture of the state that penetrates into the surface 5 with the camera, and finish the surface 5
The ratio of the permeation area of the lubricating oil to the area of is measured. In this measurement, the viscosity was 304 c. S. FIG. 14 shows the relationship between the elapsed time after injection of the lubricating oil and the permeability of the lubricating oil, using the lubricating oil of t. According to this result, the penetration rate of the lubricating oil is the worst on the finished surface by lapping. The reason is that the flatness of the finished surface 5 is as small as several μm or less, and the roughness of the surface is small unlike the finished surface 5 by other processing methods, so that the air in the oil groove 2 is hard to escape to the atmosphere. It is thought to be due to. On the other hand, it can be seen that the penetration rate of the lubricating oil on the finished surface 5 by other processing methods is high.

As described above, the finished surface 5 by lapping
Cannot be used as the guide surface 1 because of poor lubricity. When the guide surface 1 is finished by another machining method such as scraper, grinder, milling, etc., the lubricity is good, but as shown in FIG. 11, the floating amount of the sliding body from the guide surface 1 is small. In order to do so, the moving speed of the sliding body must be limited, which is not suitable for high speed operation.

[0010]

According to the present invention, a guide surface for slidably holding a slide body is provided, the surface roughness and flatness of which are set to an accuracy equal to or higher than that by lapping.
An oil groove for storing lubricating oil is formed on the surface of the guide surface, and a plurality of narrow grooves are formed on the surface of the guide surface across the oil groove so that both ends penetrate into both sides of the guide surface and a capillary phenomenon occurs. Formed.

[0011]

Since the surface roughness and flatness of the guide surface are maintained with high accuracy, the floating amount of the slide body relative to the guide surface can be reduced even when the slide body is moved at high speed.
The film thickness of the lubricating oil between the guide surface and the sliding body to immediately after starting the sliding body can be maintained in a steady state, further, bristles
It is possible to improve the lubricating oil in the penetration rate to the guide surface by the formation of fine grooves having a width enough to capillary phenomenon, also, narrow grooves
Is a closed space, lubrication is caused by the speed change of the sliding body
If the oil film thickness partially increases and the sliding body rises,
However, multiple narrow grooves cross the oil groove and both ends are
Lubrication due to open spaces penetrating both sides of the inner surface
In a steady state, the oil film thickness does not increase locally
The film thickness can be maintained, and therefore, the guide characteristics of the sliding body can be improved and the lubricity can be improved regardless of the change in the moving speed of the sliding body.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. The same parts as those described in FIG. 7 are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 1, an oil groove 2 and a plurality of oil supply holes 3 opened at the bottom of the oil groove 2 are formed in a guide surface 1 formed by lapping. Further, a plurality of narrow grooves 6 are formed in parallel on the surface of the guide surface 1 so as to cross the oil groove 2 and both ends thereof penetrate to both sides of the guide surface 1. These narrow grooves 6 are guide surfaces 1
By irradiating the guide surface 1 with a laser beam, the guide surface 1 is formed with an inclination angle of α (60 degrees) with respect to a straight line along the longitudinal direction, and the width and the arrangement interval of the adjacent narrow grooves 6 are such that a capillary phenomenon occurs. The depth of the fine groove 6 is set to 60 μm. FIG. 3 is an explanatory view showing a part of the guide surface 1 in an enlarged manner. In the figure, 7 is a lapping finish surface. A sliding body (not shown) such as a tool rest is slidably held on such a guide surface 1.

In such a structure, the slide body is guided by the guide surface 1 and reciprocally driven. At this time, since the guide surface 1 is finished by lapping, its surface roughness and flatness are highly accurate, and the guide surface 1 is hardened by the surface hardening when the fine groove 6 is formed by laser processing.
The wear resistance of can be improved. Therefore, even if the sliding body is moved at a high speed, the floating amount of the sliding body with respect to the guide surface 1 can be reduced, whereby the lubricating oil between the guiding surface 1 and the sliding body can be immediately after starting the sliding body. The film thickness of can be maintained in a steady state. Further, by forming the fine groove 6, the penetration rate of the lubricating oil into the guide surface 1 can be improved. Therefore, the guide characteristics of the sliding body can be improved and the lubricity can be improved regardless of the change in the moving speed of the sliding body.

Incidentally, 304c. S. FIG. 4 shows the relationship between the floating amount of the slide body with respect to the guide surface 1, the friction coefficient of the guide surface 1, and the moving speed of the slide body when lubricating oil having a viscosity of t is poured into the oil groove 2. As understood from FIG. 4, even if the moving speed of the sliding body changes, the floating amount of the sliding body with respect to the guide surface 1 is small. Even when the moving speed reaches 100 mm / s, the floating amount of the sliding body is as small as 1.7 μm, and the friction coefficient of the guide surface 1 is also as small as 0.38.

FIG. 5 is a graph showing the relationship between the friction coefficient of the guide surface 1 and the moving speed of the sliding body when the viscosity of the lubricant oil supplied to the guide surface 1 is changed. 82c. S. t or 17c. S. By making t small, it is possible to make the friction coefficient substantially equal to the friction coefficient of the guide surface formed by scraping.

FIG. 6 is a graph showing a comparison of the permeability of the lubricating oil between the finished surface of the guide surface 1 having the narrow groove 6 in the present invention, the conventional lapping surface, and the conventional scraping surface. The axis is the permeability of the lubricating oil, and the horizontal axis is the viscosity of the lubricating oil. Each measured value is a value 30 seconds after the lubricating oil was added. This measurement is performed by the same method as the conventional method. As can be seen from FIG. 6, it can be seen that the permeability of the lubricating oil on the guide surface 1 of the present invention is the highest.

Since the narrow groove 6 is inclined with respect to the sliding direction of the sliding body, the sliding resistance is reduced as compared with the case where the narrow groove 6 is orthogonal to the sliding direction of the sliding body. Can be made smaller.

[0018]

According to the present invention, the surface roughness and the flatness are set to the accuracy equal to or higher than that of the lapping process, and the guide surface for slidably holding the sliding body is provided, and the surface of the guide surface is lubricated. An oil groove is formed to store oil, and both ends of the guide surface cross the oil groove and both ends penetrate to both sides of the guide surface.
Since a plurality of narrow grooves with a width that causes the capillary phenomenon are formed, the surface roughness and flatness of the guide surface are maintained with high accuracy, so that even if the slide body is moved at a high speed, it is possible to reduce the floating amount, thereby, the film thickness of the lubricating oil between the guide surface and the sliding body to immediately after starting the sliding body can be maintained in a steady state, further, the capillary
Phenomenon can be improved lubricant penetration into the guide surface by the formation of fine grooves having a width enough to occur, also, small grooves closed
If there is a space, the lubricating oil
The film thickness is partially increased and the sliding body rises.
However, there are multiple thin grooves that cross the oil groove and both ends are guide surfaces.
Since there is an open space that penetrates both sides of the
Membrane in steady state without partial increase in thickness
The thickness can be maintained, and therefore, the guide characteristics of the sliding body can be improved and the lubricity can be improved regardless of changes in the moving speed of the sliding body.

[Brief description of drawings]

FIG. 1 is a plan view showing a guide surface according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional side view showing a cross-sectional shape of a narrow groove formed on the guide surface.

FIG. 3 is an explanatory view showing an enlarged part of the surface of the guide surface.

FIG. 4 is a graph showing the relationship between the friction coefficient of the guide surface, the floating amount of the slide body with respect to the guide surface, and the moving speed of the slide body.

FIG. 5 is a graph showing the relationship between the viscosity of the lubricating oil, the friction coefficient of the guide surface, and the moving speed of the sliding body.

FIG. 6 is a graph showing a comparison of the permeability of lubricating oil between a conventional example and the present invention.

FIG. 7 is a plan view showing a conventional guide surface.

FIG. 8 is a graph showing the relationship between the friction coefficient of the guide surface formed by the lapping process and the moving speed of the sliding body.

FIG. 9 is a graph showing the relationship between the friction coefficient of the guide surface formed by scraping and the moving speed of the sliding body.

FIG. 10 is a graph showing a relationship between a friction coefficient of a guide surface formed by the lapping process, a floating amount of the slide body with respect to the guide surface, and a moving speed of the slide body.

FIG. 11 is a graph showing a relationship between a friction coefficient of a guide surface formed by scraping, a floating amount of the slide body with respect to the guide surface, and a moving speed of the slide body.

FIG. 12 is a plan view of a sample for measuring the permeability of the lubricating oil.

FIG. 13 is a vertical sectional side view of the sample.

FIG. 14 is a graph showing the relationship between the passage of time after lubricating oil is injected and the permeability of the lubricating oil.

[Explanation of symbols]

 1 Guide surface 2 Oil groove 6 Fine groove

Claims (1)

(57) [Claims] 1. A guide surface for holding a sliding body slidably, the surface roughness and flatness of which are determined with an accuracy equal to or higher than that of lapping, and an oil for collecting lubricating oil on the surface of the guide surface. a groove, capillarity penetration on both sides of both ends across the oil groove on the surface of the guide surface the guide surface
A slide guide of a machine tool, characterized in that a plurality of narrow grooves having a width that causes the occurrence of the above are formed.