JPS639785Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an orifice type hydrostatic bearing having a large moment load capacity and a large moment rigidity.

Conventional orifice-type hydrostatic bearings are either constructed by providing an orifice with a minute hole diameter at a suitable location on the bearing surface, or simply for supplying pressure fluid to the bearing surface.
Alternatively, a pressure fluid supply channel including an orifice as shown in FIG. 1 is provided.

That is, in FIG. 1, an orifice 12a that communicates with the bearing surface 11a from the outside of the bearing is provided approximately at the center in the axial direction of the bearing 1a, which is a fixed side member,
In the bearing surface, a supply groove 13a for supplying pressurized fluid from the orifice to the bearing surface extends toward both ends of the bearing, forming a substantially H-shaped supply groove, and forming a shaft that cooperates with the bearing surface. 2a is supported in the radial direction.

However, among these conventional orifice type hydrostatic bearings, the former has the problem that when a moment load is applied, the shaft and bearing surface come into contact at the end of the bearing, resulting in wear of the shaft and bearing surface, and even a seizure accident. Ta.

In the latter case, the approximately H-shaped pressure fluid supply groove formed on the bearing surface provides a higher moment load capacity than the former, but it is also possible to obtain a higher moment load capacity than the former. When a moment load is applied to the shaft, there is still the problem of contact between the shaft and the bearing surface, and a sufficient moment load capacity is not obtained.

The object of the present invention is to solve these problems of conventional orifice-type hydrostatic bearings and to obtain an orifice-type hydrostatic bearing having a high moment load capacity.

Next, the present invention will be explained with reference to the following figures. Second
The figure shows a first embodiment of the present invention, and FIG. 3 is an explanatory view comparing the first embodiment with a conventional bearing and showing its effect. In FIG. 2, approximately at the center of the bearing 1, two rows of orifices 12 are provided in each row in the circumferential direction, communicating with the outside of the bearing and opening into the bearing surface 11. The orifice has a small diameter hole in the opening 121 to the bearing surface in order to obtain a pressure fluid throttling effect, and the pressure fluid is directed toward each end of the bearing including the small diameter opening. A supply groove 13 is formed, and furthermore, a deep groove 14 is formed discontinuously along the bearing surface end 15 near the end of the bearing surface, and is deeper than the supply groove. The end of the supply groove 13 opposite to the deep groove 14 is connected to the non-groove land portion 20, and the supply grooves 13 on both sides of the land portion 20 at the center of the bearing portion face each other. Next, FIG. 3 shows the state of the pressure distribution that occurs on the bearing surface 11 when a moment load acts on the shaft 2 and the shaft center is tilted by an angle θ in the bearing configured in the first embodiment.

That is, in the figure, when a moment load acts, for example, at the left bearing surface end 15, the pressure distribution on the upper side where the clearance between the shaft and the bearing surface is large and on the lower side where the clearance is small is as shown by a solid line. As shown by the dotted line in this figure, when the pressure distribution in the case where the deep groove 14 is not provided is P ₁ and P ₂ , the pressure difference between the upper side and the lower side is (P ₁ - P ₂ ), and it is also shown by the solid line. The respective pressure distributions when the deep groove 14 is provided are P ₃ ,
When P ₄ , the pressure difference between the upper and lower sides is (P ₃ − P ₄ )
Therefore, there is a relationship of (P ₃ −P ₄ )>(P ₁ −P ₂ ).

That is, at the end of the bearing surface, the deep groove 14
By providing
Since the viscous throttling effect in the gap between the deep groove 14 and the bearing end 15 is greater than the throttling effect of the orifice, the fluid exiting the orifice is effectively introduced into the deep groove through the supply groove. As a result, a large pressure is generated in the deep groove, and conversely, on the upper side where the gap is large, the pressure fluid that existed in the deep groove is quickly discharged outside the bearing, and the pressure fluid that should be supplied from the orifice is affected by the throttling effect of the orifice. As a result, the pressure decreases.

This is the same for the right bearing end in the figure, and the restoring force that acts to correct the inclination θ is the difference between the pressure generated on the lower side and the upper side, so compared to the case where there is no deep groove, The deep groove configuration has a large restoring force, that is, a large moment load capacity and moment stiffness.

Next, FIG. 4 shows a second embodiment of the present invention, which is applied to a square thrust bearing pad, in which a suitable number of deep grooves 14 are discontinuously provided in the bearing surface 11 along the bearing end. , a pressure fluid supply groove 13 extending from the deep groove toward the center of the bearing surface;
The configuration is such that an orifice 12 is provided at a suitable location in the supply groove. And supply groove 13 is deep groove 1
The end opposite to 4 connects to the non-groove land 20, and the supply grooves 13 on both sides of the land 20 in the center of the bearing part face each other.

As explained above in the embodiments, by providing discontinuous deep grooves at the end of the bearing surface, when the axis is tilted θ compared to the case where there is no deep groove,
The difference between the pressure on the bearing surface side where the clearance is smaller and the pressure on the bearing surface side where the clearance is larger increases, increasing the restoring force to correct the inclination of the shaft center, and increasing the moment load capacity and moment rigidity. Larger bearings can be obtained.

This prevents contact between the shaft and the bearing surface even when a large moment load or an impactful moment load is applied.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing a conventional bearing, Fig. 2 is a longitudinal sectional view showing a first embodiment of the present invention, Fig. 3 is an explanatory diagram showing the operation of the first embodiment, and Fig. 4 is a longitudinal sectional view showing the present invention. FIG. 3 is a front view showing a second embodiment of the invention. Explanation of symbols, 1...Bearing, 11...Bearing surface, 1
2...Orifice, 13...Supply groove, θ...Inclination of axis, 14...Deep groove, 2...Axis, 20...
land department.

Claims (1)

[Claims for Utility Model Registration] (1) The bearing surface of a hydrostatic bearing has an appropriate number of deep grooves discontinuously drilled along the end of the bearing surface near the end of the bearing surface. It has a pressure fluid supply groove connected to the deep groove, extending toward the center of the bearing part, and shallower than the deep groove, and an orifice bored at a suitable position in the supply groove, and the supply groove is deep. An orifice type hydrostatic bearing characterized in that an end opposite to the groove is connected to a non-groove land portion, and supply grooves on both sides of the land portion in the center of the bearing portion face each other. (2) The orifice type hydrostatic bearing according to claim 1, wherein the hydrostatic bearing is a radial type. (3) The orifice type hydrostatic bearing according to claim 1, wherein the hydrostatic bearing is a thrust type.