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High Performance Centerless Grinding Machine C4520FS

Koyo Machine Industries Co., Ltd. has developed a

new-type centerless grinding machine C4520FS for

stabilizing the grinding accuracy and simplifying the

loading system. Its features are: high rigidity, fixed work

rest, and slant-type regulating wheel slide.

(developed under C21 Project of Koyo Machine Industries

Co., Ltd.)

Work center height is set at the same height of the grinding wheel center, which provides stable grinding accuracy.

The slant-type regulating wheel slide with the inclination of 6 was practically adopted first in the world. As a result, the

fluctuation of the center height angle, which has a great influence on the centerless grinding accuracy, was restrained to

minimum.

Features

As diameters of grinding wheel and regulating wheel

change, the contact point with a workpiece also changes

greatly. Subsequently, roundness would become unstable

because the center height angle fluctuates accordingly.

The center height angle (R) is kept constant even if

diameters of grinding wheel and regulating wheel changes, so

the contact point with a workpiece does not change. Therefore

the roundness accuracy can be maintained.

Conventional machine (flat type)

Grinding wheel WorkpieceRegulating wheel

Developed machine (half-slant type)

R1

R2

Grindingwheel

Workpiece Regulating wheelMaximum diameter

Maximum diameter

Minimum diameter

Minimum diameter

Maximum diameter

Maximum diameter

Minimum diameter

Minimum diameter

R(constant center heightangle)

KOYO MACHINE INDUSTRIES CO., LTD.

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7 6 Koyo Engineering Journal English Edition No.163E (2003)

Specification

Work rest is fixed so that the loading system is simplified.

The developed machine is the grinding wheel feeding type, in which the work position is kept constant when the diameter

of grinding wheel changes. No need to adjust the position of the loading system.

High rigidity

The feed screws in both slides are fixed in the center. This new system results in higher rigidity against thermal distortion.

Since feed screws are fixed at both ends of the bed,

influence on workpiece dimension caused by thermal

distortion of the bed is high.

Since feed screws are fixed in the center of the bed,

influence on workpiece dimension caused by thermal

distortion of the bed is low.

Precision/high-efficiency grinding of: inner/outer rings or

rollers of bearings, components for compressor, and outer

diameter of shafts for automotive components, etc.

Application

Conventional machine

(grinding wheel is fixed)

Developed machine

(work rest is fixed, grinding wheel feeding type)

When grinding wheel diameter is large

When grinding wheel diameter is smallWorkpiecemoves

Grinding wheel moves

When grinding wheel diameter is large

When grinding wheel diameter is small

Workpiece

A'

A

B'

B

(A'A) > (B'B)

Conventional type Center-fixed type

Thermaldistortion

Thermaldistortion

Item Grinding wheel Regulating wheel

Machining Range, mm u1~u50

Dimensions (OD W ID) u455 205 u203.2 u305 205 u177.8

Rotational speed, min1 2 500 12~230

Circumferential speed, m/s 60

Inclination, degree 5 ~ +5

Minimum feeding unit,lm 0.1 0.1

Maximum feed speed, mm/s 33 21

Drive motor, kW 7.5~22 1.5

Center height of grinding

wheel, mm980 from floor

Floor space (W D), mm 1 900 1 430

Machine weight, kg 5 000

KOYO MACHINE INDUSTRIES CO., LTD.