Method for lapping valve seats using a single point cutting tool
First Claim
1. A method for lapping a valve seat of a plurality of pre-existing valve seats with corresponding valve guides in an engine cylinder head utilizing a spindle assembly in a machining apparatus, the spindle assembly having a spindle adapted for rotation around a vertical axis, the method comprising:
- providing a carriage head at a lower portion of the spindle assembly, the carriage head having a carriage head control mechanism for effecting radial feed of the carriage head relative to the vertical axis;
attaching a universal cutting tool to the carriage head, the universal cutting tool having a single cutting point;
attaching a pilot at the lower portion of the spindle assembly so that the pilot is centered on the vertical axis, wherein the pilot is adapted to fit within a valve guide;
centering the spindle assembly with respect to the valve seat by inserting the pilot into the valve guide corresponding to the valve seat;
providing lapping parameters for a desired valve seat profile to a system controller, the desired valve seat profile comprising a plurality of segments, each segment having a segment length and at least one segment angle;
in the system controller, using the segment length and at least one segment angle for each of the plurality of segments to calculate each of a carriage head feed rate of the carriage head and a vertical feed rate and rotational speed of the spindle for lapping each segment of the valve seat profile using the lapping parameters; and
separately for each segment of the desired valve seat profile, generating control signals in the system controller for controlling the vertical feed rate and the rotational speed of the spindle and controlling the carriage head feed rate independent of the vertical feed rate and the rotational speed.
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Accused Products
Abstract
The cutting tool for machining valve seats comprises a driving system, a spindle assembly, and a system controller. The driving system provides rotational movement and vertical movement for the spindle assembly which is controlled by the system controller. The spindle assembly further comprises a spherical sheath providing capability to align a spindle to any valve seat orientation, the spindle for rotating a universal cutting blade, a machining head attachable to the spindle, a tool holder carriage for holding the universal cutting blade, and a pinion feed driving assembly or set of connecting rods for controlling the cutting radius of the universal cutting blade. The pinion feed driving assembly is driven by a servo motor which moves the spindle vertically and independent from the vertical movement of the spindle assembly and the rotational movement of the spindle. The system controller includes memory and programming for controlling the operation of the universal cutting blade. An operator can input the parameters that define the geometry of the valve seat profile. These parameters are used by the system controller to determine the rotational speed, the vertical feed of the machine spindle, and the inward or outward feed of the universal cutting tool.
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Citations
22 Claims
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1. A method for lapping a valve seat of a plurality of pre-existing valve seats with corresponding valve guides in an engine cylinder head utilizing a spindle assembly in a machining apparatus, the spindle assembly having a spindle adapted for rotation around a vertical axis, the method comprising:
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providing a carriage head at a lower portion of the spindle assembly, the carriage head having a carriage head control mechanism for effecting radial feed of the carriage head relative to the vertical axis;
attaching a universal cutting tool to the carriage head, the universal cutting tool having a single cutting point;
attaching a pilot at the lower portion of the spindle assembly so that the pilot is centered on the vertical axis, wherein the pilot is adapted to fit within a valve guide;
centering the spindle assembly with respect to the valve seat by inserting the pilot into the valve guide corresponding to the valve seat;
providing lapping parameters for a desired valve seat profile to a system controller, the desired valve seat profile comprising a plurality of segments, each segment having a segment length and at least one segment angle;
in the system controller, using the segment length and at least one segment angle for each of the plurality of segments to calculate each of a carriage head feed rate of the carriage head and a vertical feed rate and rotational speed of the spindle for lapping each segment of the valve seat profile using the lapping parameters; and
separately for each segment of the desired valve seat profile, generating control signals in the system controller for controlling the vertical feed rate and the rotational speed of the spindle and controlling the carriage head feed rate independent of the vertical feed rate and the rotational speed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for lapping a valve seat in an engine cylinder head comprising:
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determining a target valve seat profile, the target valve seat profile comprising a plurality of segments, each segment having a segment length and a segment angle;
providing a machine head having a spindle assembly adapted for rotation around a vertical axis and a carriage disposed at a lower portion of the spindle assembly at an inclination angle relative to a horizontal plane perpendicular to the vertical axis, the carriage adapted for radial movement relative to the vertical axis;
attaching a cutting tip to the carriage, the cutting tip having a single cutting point;
centering the vertical axis within the valve seat;
in a system controller, calculating a radial feed rate of the carriage and a vertical feed rate, a vertical displacement and a rotational speed of the spindle for creating each segment of the plurality of segments;
for each segment, generating control signals comprising a carriage control signal for moving the carriage at the calculated radial feed rate and a spindle control signal for moving the spindle assembly at the calculated vertical feed rate and the calculated rotational speed for the calculated vertical displacement; and
lapping the plurality of segments one segment at a time to produce the target valve seat profile. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification