Abstract: A method and apparatus for grinding a cylindrical surface of a workpiece by a traverse movement of a grinding wheel having a relatively narrow grinding surface. To improve the cylindricity of cylindrical surface, the traverse grinding is divided into a rough traverse grinding and a finish traverse grinding. In the rough traverse grinding, a traverse girding is carried out with a large depth of cut which would causes a deterioration of the cylindricity at one end of the cylindrical surface. In the finish traverse grinding, a traverse girding is carried out with a small depth of cut to improve the cylindricity. In another embodiment, one of grinding conditions such as the traverse speed of the grinding wheel, the rotational speed of the workpiece and the peripheral speed of the grinding wheel is changed when the grinding wheel approaches an end of the cylindrical surface at which the traverse grinding ends so as to make the grinding force constant, thereby improving the cylindricity of the cylindrical surface.

Abstract: A numerical control grinding machine, in which rough grinding and finish grinding wheels are used to machine a workpiece into a predetermined shape. A sensor detects the finish grinding wheel contacting the workpiece surface when shifting from the rough grinding to finish grinding operations and determines its position. The numerical controller of the grinding machine calculates the difference between actual and theoretical sizes of the workpiece and completion of the rough grinding operation based on the finish grinding wheel position. After that, the controller compensates the rough grinding wheel position in the next machining cycle for the difference calculated by the controller.

Abstract: A numerical control apparatus for machining non-circular workpieces such as a cam and the like has been disclosed. The cam and the like are used in changing the operation from rotational to linear motion. In designing the shape of the cam and the like, lift data prescribing the relationship between the rotational and linear motions is used. The lift data is given by the position sequence on the linear motion corresponding to a number of discrete rotational angles. Also, the tolerance of the positions is given from a functional aspect. The lift data is converted into profile data prescribing the shape of the cam and the like after being smoothed within the tolerance by a regression analysis, and machining of the non-circular workpieces is effected according to the profile data.

Abstract: A numerically controlled internal grinding machine for grinding a workpiece by a rough grinding operation with a rough grinding wheel and a finish grinding operation with a finish grinding wheel. The grinding machine detects the load power of a motor which drives the finish grinding wheel in order to determine a compensation value to enable subsequent compensation due to wear of the rough grinding wheel. In the successive rough grinding operation, the relative position of the workpiece is compensated for according to the determined compensation value, so that the diameter of the workpiece after the rough grinding operation is maintained at a desired constant value regardless of the wear of the rough grinding wheel.

Abstract: A numerically controlled machine tool for machining a non-circular workpiece according to profile data. The servomotor drive unit of the machine tool includes a frequency voltage converter which outputs a velocity compensation signal proportional to the frequency of position command pulses in the servomotor drive units. A position error signal is modulated by the velocity compensation signal. The numerical controller of the machine tool can measure the position error and phase error, and can compensate for these errors. The numerical controller operates according to ideal profile data and measures the actual position change of a tool slide corresponding to the angle position change of a main spindle. Then, the numerical controller calculates the position error and phase error depending on the actual position change and ideal profile data, and produces execution profile data which are compensated for position error.

Abstract: In a numerical control grinding machine using a grinding wheel made of cubic boron nitride, a computerized numerical controller controls the infeed movement of a wheel head to effect a rough grinding and a first fine grinding on a rotating cylindrical workpiece by the grinding wheel and to halt the first fine grinding in response to a sizing signal from a sizing device which measures the diameter of the workpiece being ground. At the halt of the first fine grinding, the numerical controller advances rest jaws to press the workpiece upon the grinding wheel until another sizing signal is issued from the sizing device. Until the number of the workpieces ground after each truing operation reaches a predetermined number, the numerical controller increase the infeed rate of the grinding wheel in each of the rough and first fine grindings toward a desired infeed rate on a step-by-step basis.

Abstract: An operator's panel for a numerical controller of a grinding machine comprises a main frame of a generally box shape, which is carried on a front portion of a bed of the grinding machine for pivotal movement about a horizontal axis. A manual pulse generator for supplying the numerical controller with pulse signals is mounted in the main frame, and a manual feed handle is secured to an input shaft of the pulse generator. A mechanism is further provided for locking the main frame at such an angular position as desired by an operator of the grinding machine.

Abstract: A device for detecting the position of a wheel head of a grinding machine is provided with a housing secured to the wheel head and a support rod secured at its opposite ends to a stationary base in parallel relation with the moving direction of the wheel head. The support rod passes through the housing at a pair of holes formed on opposite end walls of the housing. A linear scale is secured to the housing within the housing, and a scanning unit is fixed on the support rod within said housing for reading scale gratings on the linear scale when the housing is moved bodily with the wheel head relative to the support rod.

Abstract: In a centerless grinding machine, a work blade for rotatably carrying a workpiece is movable by a blade feed device in a direction normal to a first line extending across the axes of grinding and regulating wheels. Present diameters of the wheels, a desired finish diameter of the workpiece and a predetermined value representing the sine of a center height angle are stored in a data memory. The center height angle is represented by the sum of angles which a second line extending across the axes of the grinding wheel and the workpiece and a third line extending across the axes of the regulating wheel and the workpiece respectively make relative to the first line when the workpiece is finished to the desired finish diameter. When each of the wheels is dressed, a data rewriting circuit replaces the diameter of each wheel being stored in the data memory with a new diameter after such dressing.

Abstract: A regulating wheel dressing system in a centerless grinder, having a dressing tool for dressing a regulating wheel, which dressing tool is adapted to be feed-controlled in a direction parallel to the axis of rotation of the regulating wheel and also in a crossing direction by a feed control means, which in turn is controlled biaxially simultaneously by a control means. Coordinate values of plural points on a rotated hyperboloid of one sheet of revolution to be formed on the regulating wheel are calculated and the dressing tool is feed-controlled for coordinate interpolation between the plural points with those coordinate values as target points. The regulating wheel can be dressed to the rotated hyperboloid of one sheet of revolution in high accuracy independently of changes of its diameter and even where it is stepped for supporting a stepped work.

Abstract: A truing apparatus includes a truing tool supported on a tool support movable radially and axially of a grinding wheel having a rounded corner and drivable by a feed drive unit coupled to the tool support to move along a predetermined path for truing the rounded corner of the grinding wheel. At least one contact member for contacting outer peripheral and end surfaces of the grinding wheel is mounted on the tool support, and a sensor is also mounted on the tool support for detecting a contact between the contact member and the grinding wheel. A feed control system controls the feed drive unit for moving the truing tool along the predetermined path. The feed control system controls the feed drive unit so that the contact member will move radially and axially of the grinding wheel until the sensor is actuated immediately after one truing process and immediately before a next truing process.

Abstract: An apparatus for truing a grinding wheel includes a stylus movable in response to movement of a truer in synchronism therewith, and a template disposed in confronting relation to the stylus with a gap left therebetween. The truer is controlled in its motion by servomotors driven in response to a command issued from a numerical control unit. When the truer is caused by the numerical control unit to move out of control for some reasons, the stylus is brought into engagement with the template, thereby protecting the truer and a grinding wheel being trued thereby against damage which would otherwise result from such uncontrolled movement of the truer. When the truer is to be advanced for truing infeed against the grinding wheel, the stylus is disconnected by a clutch device from the truer, and only the truer is moved in the forward direction while maintaining a proper gap between the stylus and the template.

Abstract: A cam grinding machine for grinding a cam in accordance with the profile of a master cam (6). The machine is equipped with an apparatus for substantially compensating lift error of the cam due to grinding wheel wear, said apparatus being provided with a planetary gear mechanism (30) so as to change a large diameter roller (22) contacting the master cam (6) into a small diameter roller (23) when the grinding wheel diameter is reduced.

Abstract: Wear on the dressing tool is derived from an amount of movement that a grinding wheel is advanced until issuance of a signal from a sizing device for correcting data on the radius of the grinding wheel. The data on the radius of the grinding wheel is thus indicative of an actual radius of the grinding wheel regardless of a variation in the grinding wheel radius due to the wear of a dressing tool. Accordingly, the grinding surface of the grinding wheel can be exactly positioned at a grinding start position after the grinding wheel has been returned to its original position upon power supply failure, emergency machine shutdown or the like, so that any unwanted interference between the grinding wheel and a workpiece can be avoided.

Abstract: A workpiece rotational speed controller having a pulse counter responsive to a pulse signal generated from a pulse generator for indicating the actual angular position of a cam shaft during grinding on a cam grinding machine and a comparator for comparing a count value of the counter with any one of set values which are set in a plurality of digital switches to designate respective speed change positions. A region detection counter is further provided, which counts any coincidence signal from the comparator so as to enable a command voltage generator to apply to a servomotor for cam shaft drive a command voltage that changes step by step in correspondence to the region detection counter output. This counter output is also applied to a gate circuit, which is thus enabled to selectively apply the set values of the digital switches to the comparator.

Abstract: An apparatus for truing and dressing a grinding wheel made of cubic boron nitride is provided. A support head supporting a truing wheel and another support head supporting a dressing roll are separately and independently arranged on a wheel support of a grinding machine. The truing wheel is rotated in the same direction as is the grinding wheel so as to true the grinding wheel in an up-cut manner, and the dressing roll is rotated in a direction opposite to that of the grinding wheel so as to dress the grinding wheel in a down-cut manner. The dressing roll is fed toward the grinding wheel to be ground thereby and then returned a predetermined amount away from the grinding wheel prior to a truing operation.

Abstract: A grinding machine, having a wheel carrier with a rotatable cubic boron nitride grinding wheel mounted on a bed. The wheel carrier is slidable with respect to a work support device and a truing device, which are selectively opposed to the grinding wheel through movement of a traverse table. Feed and feed control devices are provided to feed the wheel carrier from a transient original position to an advanced position in a grinding operation. A detecting device is further provided to detect an absolute original position of the wheel carrier. The feed control device is arranged such that, whenever a truing instruction is supplied, the wheel carrier is retracted to the absoluted original position and then, is advanced therefrom to a truing position incremented by a predetermined truing infeed amount from the advanced position.

Abstract: A fluid bearing for rotatably supporting a rotary shaft comprising a hydrodynamic bearing formed on a loaded side. A hydrostatic bearing is formed in axially juxtaposed relationship with the hydrodynamic bearing. An annular partition groove is formed between the hydrodynamic and hydrostatic bearings for supplying pressurized fluid from the hydrostatic bearing to the hydrodynamic bearing.

Abstract: A high rigidity fluid bearing adapted to rotatably support a rotary shaft on a stationary base and a method for manufacturing the same. The fluid bearing is provided with a bearing bushing which includes a plurality of fluid pockets spaced apart in the circumferential direction, a land portion surrounding the fluid pockets, throttles connected respectively to the fluid pockets, and a raised land formed in each of the fluid pockets. On the bearing bushing, a deformable portion is formed around the raised land. The bearing bushing is urged and fixed to an arbor inserted therein and having a diameter smaller than that of the bore thereof at one end of each raised land so as to form a wedge-shape clearance between the raised land and the arbor. The outer periphery of the bearing bushing fixed to the arbor is machined to a true or proper circle. After removed from the arbor, the bearing bushing is fitted to the stationary base.