JPH0444894Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to a structure for preventing an increase in load on a bearing that supports a rotating shaft.

Prior Art In the bearing section of a main shaft that rotates at high speed, the bearing housing usually has high rigidity, so it cannot absorb thermal expansion in the outer circumferential direction of the bearing due to temperature rise, resulting in tightening of the bearing rolling surface and an increase in preload. Conventionally, as a method of preventing this increase in preload, a method has been adopted in which an annular groove is provided in the bearing housing in the axial direction to weaken the rigidity in the circumferential direction and absorb thermal expansion.

Problems that the invention aims to solve: When an annular groove is provided in the bearing housing, the gap in the annular groove deteriorates thermal conductivity, causing the bearing temperature to rise, causing thermal expansion of the bearing and increasing preload, repeating a vicious cycle. have.

Means for Solving the Problem A first annular groove parallel to the axis is carved in the bearing housing, the first annular groove is filled with a material having elasticity and high thermal conductivity, and the first annular groove is filled with a material having elasticity and high thermal conductivity. A second annular groove for cooling is carved on the outer periphery of the annular groove, and a cooling fluid is allowed to flow through the second annular groove, thereby making the bearing housing a low-rigidity structure with good cooling efficiency.

Embodiment An embodiment of the present invention will be described below based on the drawings (FIG. 1).

A bearing housing 2 is fitted onto the headstock 1, and a main shaft 4 is rotatably supported by a plurality of bearings 3 fitted into a center hole 2a of the bearing housing 2.
A groove 2b having heat dissipation fins is formed on the outer periphery of the cylindrical portion of the bearing housing 2, so that the cooling fluid supplied from the flow path 1a provided in the headstock passes through the groove 2b and is discharged from the flow path 1b. It's summery. Further, an annular groove 2c parallel to the axis is carved from the right side of the cylindrical portion, and the annular groove 2c is filled with a filler 5 having elasticity and high thermal conductivity. For example, silicone rubber manufactured by Shin-Etsu Silicone can be used as the filler 5. This material is prepared by adding a small amount of curing agent to the paste-like base material KE1220 and easily filling the annular groove 2c with a syringe.
After 3 days at room temperature of 25℃, the elongation rate is 47%, the hardness is HS73, and the tensile strength is 21Kg/cm ² .
Thermal conductivity 35×10 ⁴ cal/cm. sec.℃ becomes an elastic body.

The filler 5 is not limited to silicone rubber, but any elastic material with high thermal conductivity that can be filled can be used.

Function When the main shaft 4 is rotated at high speed, the temperature of the bearing 3 gradually increases. The heat of the bearing 3 is transmitted to the outer periphery of the bearing housing 2 via the filler 5 with high thermal conductivity, such as silicone rubber, filled in the annular groove 2c of the bearing housing 2, and is transferred to the outer periphery of the bearing housing 2 by the cooling fluid flowing in the cooling groove 2b. The bearing 3 is cooled and the temperature rise of the bearing 3 is suppressed. However, the temperature of the bearing 3 rises to a certain extent, and the outer diameter increases due to thermal expansion. The center hole 2a of the bearing housing 2 into which the outer ring of the bearing 3 is fitted has a thin, cantilevered, low-rigidity structure with an annular groove 2c.
Since the annular groove 2c is filled with an elastic material such as silicone rubber, it is pressed against the bearing 3 whose outer diameter has increased due to thermal expansion, and the hole diameter increases, absorbing the thermal expansion and being applied to the bearing. The existing preload will not be increased more than necessary.

Effects As detailed above, the present invention provides an annular groove parallel to the axis in the bearing housing, fills it with an elastic material with high thermal conductivity, and provides an annular cooling groove on the outer periphery of the annular groove. Since the cooling fluid is allowed to flow, the low rigidity structure of the bearing housing is maintained, and the thermal conductivity is good.The heat of the bearing is dissipated by the cooling fluid, which suppresses the temperature rise of the bearing and reduces thermal expansion. This has the effect of absorbing the pressure and preventing an increase in bearing preload.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the load increase prevention structure of the embodiment. 2... Bearing housing, 7... Lid, 2c... Annular groove, 3... Bearing, 4... Main shaft, 5... Filler,
8,9...Oil ring.

Claims (1)

[Claims for Utility Model Registration] (1) In a bearing mechanism for a rotating shaft, a first annular groove parallel to the axis is carved in the bearing housing, and the first annular groove has elasticity and thermal conductivity. A second annular groove for cooling is carved on the outer periphery of the first annular groove, and a cooling fluid is flowed through the second annular groove, thereby making the bearing housing a low-rigidity structure with high cooling efficiency. A bearing load increase prevention structure characterized by the following. (2) The bearing load increase prevention structure according to claim 1, wherein the material having elasticity and high thermal conductivity is silicone rubber.