JP2004060757A - Bush for sliding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bush for sliding that hardly causes a seizure accident even in a high-speed linear movement. <P>SOLUTION: This bush for sliding has a hollow cylindrical shape, and has a meandering spiral groove continuing from the upper end to the lower end in the inner peripheral surface. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sliding bush. The sliding is performed by combining a bush with a guide post or a guide shaft. A linear guide post or a guide shaft is inserted into a hollow portion of a hollow cylindrical bush to perform a linear motion. Therefore, the inner peripheral surface of the bush and the outer surface of the guide post or the guide shaft slide in contact with each other.
[0002]
[Prior art]
3A and 3B are schematic views of a conventional sliding bush, in which FIG. 3A is a front sectional view taken along a plane passing through a central axis, and FIG. 3B is a plan view thereof. It has a hollow cylindrical shape with an inner diameter d, an outer diameter D, and a length 1, and its inner peripheral surface has no irregularities and forms a cylindrical side surface.
[0003]
As other conventional sliding bushes, there are known those in which a circular recess is formed on an inner peripheral surface to provide an oil reservoir, or a cylindrical solid lubricant or a columnar oil-containing alloy is embedded in a circular recess. ing. After the lubricating oil is injected, the guide post or the guide shaft is inserted into the hollow portion of the bush, and linearly moves while sliding on each other.
[0004]
Still another known sliding bush is one in which a circumferential or spiral oil supply groove is formed on the inner peripheral surface.
[0005]
[Problems to be solved by the invention]
However, when a conventional sliding bush is used for high-speed repetitive linear motion of 1500 to 2500 cycles per minute, oil runs out and the sliding bush and the guide post or the guide shaft are seized. This is a problem that tends to occur. In addition, if the oil runs out and the lubrication is insufficient, the friction increases, and heat is generated to thermally expand the guide post and the guide shaft, so that the friction further increases, and finally, a seizure accident easily occurs. Further, there is a problem that the lubricating oil evaporates or burns, resulting in insufficient lubrication and seizure accidents.
[0006]
Therefore, an object of the present invention is to provide a sliding bush in which seizure accidents do not easily occur even when a high-speed linear motion is performed.
[0007]
[Means for Solving the Problems]
The above object is a sliding bush according to the present invention as defined in claim 1, that is, a hollow cylindrical sliding bush, wherein a meandering spiral groove is formed on the inner peripheral surface from the upper end to the lower end. Is achieved by the sliding bush described above.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0009]
FIG. 1 is a developed view of an inner peripheral surface of a sliding bush according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a meandering spiral groove formed on the inner peripheral surface of the sliding bush according to the embodiment of the present invention.
[0010]
On the inner peripheral surface 3 of the sliding bush, meandering spiral grooves 61, 62, 63, 64, 65 are formed. As is apparent from the explanatory diagram (FIG. 2) in which the meandering spiral grooves 61, 62, 63, 64, and 65 are connected to form a single meandering spiral, the average spiral 60 obtained from the meandering spiral and the circumference 7 are formed. The angle θ is about 5 to 10 ° and is constant. Therefore, the pitch of the average helix is πdtanθ. The meandering spiral groove is a sine wave with a period λ and an amplitude a / 2 along the average spiral 60, and the groove width is a. Therefore, the valley 661 of the upper edge 66 of the meandering spiral groove 61, 62, 63, 64, 65 contacts the average spiral 60, and similarly, the peak 671 of the lower edge 67 of the meandering spiral groove 61, 62, 63, 64, 65. Is in contact with the average helix 60. In the present embodiment, 3λ = πd, and the number of meandering is three per round. The valleys and peaks of the meandering spiral groove face each other on the opposing inner peripheral surface 3 on the straight line passing through the central axis 5, and the valleys and valleys do not face each other, and the peaks do not face each other.
[0011]
And, while the groove width of the meandering spiral grooves 61, 62, 63, 64, 65 is a, the distance of the inner peripheral surface 3 remaining between the adjacent meandering spiral grooves is w, and a / w Is about 3/4. If the ratio of a / w is much larger than 3/4, the total area of the sliding surface becomes insufficient, the guide becomes insufficient, and play and wear easily occur, and the sliding position accuracy is deteriorated. On the other hand, if the ratio of a / w is significantly smaller than 3/4, the total area of the oil sump is insufficient, the lubricating effect is deteriorated, and oil shortage and seizure are likely to occur.
[0012]
Using the sliding bush of the present embodiment, first, after lubricating into the meandering spiral groove, insert the guide post or the guide shaft into the hollow portion of the sliding bush and assemble them to perform mutual sliding motion. The outside air circulates along the average spiral, but the lubricating oil is retained in the ridge at the upper edge and the valley at the lower edge of the meandering spiral groove, and can supply oil to the sliding surface for a long period of time. On the other hand, in the case of the conventional spiral groove, the lubricating oil is not retained and flows out from both outlets of the spiral groove within a short period of time, so that the lubricating oil disappears from the spiral groove. In particular, when a high-speed sliding motion is performed, the oil runs out within a very short period of time.
[0013]
【The invention's effect】
Since the sliding bush according to the present invention has a meandering spiral groove continuous from the upper end to the lower end in the central axis direction formed on the inner peripheral surface, the lubricating oil is caught by the upper edge peaks and the lower edge valleys. As a result, the lubricating oil is supplied to the sliding surface for a long period of time, so that there is an effect that the running out of oil hardly occurs even at high speed sliding operation.
[0014]
Further, in the sliding bush according to the present invention, since the average spiral passes inside the valley at the upper edge of the meandering spiral groove and passes inside the mountain at the lower edge, the outside air can easily flow and cool the sliding surface. And has the effect of suppressing a rise in temperature.
[Brief description of the drawings]
FIG. 1 is a development view of an inner peripheral surface of a sliding bush according to an embodiment of the present invention.
FIG. 2 is an explanatory view of a meandering spiral groove formed on the inner peripheral surface of the sliding bush according to the embodiment of the present invention.
3A and 3B are schematic views of a conventional sliding bush, in which FIG. 3A is a front sectional view cut along a plane passing through a central axis, and FIG. 3B is a plan view thereof.
[Explanation of symbols]
3 Inner peripheral surface 5 Center axis 60 Average helix 61 Meandering spiral groove 62 Meandering spiral groove 63 Meandering spiral groove 64 Meandering spiral groove 65 Meandering spiral groove 66 Upper edge 661 Upper valley 671 Mountain 7 circumference

Claims (5)

A sliding bush having a hollow cylindrical shape, wherein a meandering spiral groove is formed on an inner peripheral surface of the sliding bush so as to be continuous from an upper end to a lower end. A sliding bush, wherein an average spiral of the meandering spiral groove passes inside a valley at an upper edge of the meandering spiral groove and passes inside a mountain at a lower edge of the meandering spiral groove. The sliding bush according to claim 1, wherein an angle θ between the average spiral of the meandering spiral groove and the circumference of the inner peripheral surface is 5 to 10 °. The sliding bush according to any one of claims 1 to 4, wherein a ratio of a width of the meandering spiral groove to a width of the other portion is 3/4. The sliding bush according to any one of claims 1 to 4, wherein the number of meandering is an odd number per round.

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