Cam grinding machine and cam grinding method

Patent metadata

Field	Value
Publication number	US-10322489-B2
Application number	US-201615350680-A
Country	US
Kind code	B2
Filing date	Nov 14, 2016
Priority date	Nov 20, 2015
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

A cam grinding method includes: a common base circle portion setting step of obtaining an angular range of a common surface based on first cam lift data of a first cam and second cam lift data of a second cam; a first cam grinding step of grinding the first cam; a second cam grinding step of grinding the second cam; and a common base circle portion traverse grinding step of, after the second cam grinding step, moving a grinding wheel in a traverse direction to perform spark-out of an unground part remaining at the boundary between the first and second cams.

First claim

What is claimed is:

1. A cam grinding machine that grinds a composite cam, wherein
the composite cam includes
a first cam that has a first base circle portion having a first radius and a fixed lift height from a central axis to its outer peripheral surface, and a first cam portion having a varying lift height from the central axis to its outer peripheral surface, and
a second cam that has a second base circle portion having the first radius and the fixed lift height from the central axis to its outer peripheral surface, and a second cam portion having a varying lift height from the central axis to its outer peripheral surface,
the first cam and the second cam are coaxially disposed so as to adjoin each other in an axial direction,
the first cam and the second cam have different shapes from each other, the shape of the first cam corresponding to first cam lift data and the shape of the second cam corresponding to second cam lift data, and
at least a part of the outer peripheral surface of the first base circle portion and at least a part of the outer peripheral surface of the second base circle portion are flush with each other to form a common base circle portion, the cam grinding machine comprising:

a base unit that serves as a base;
a spindle device placed over the base unit and including a workpiece rotating device that rotatably supports the composite cam about the central axis;
a grinding wheel device placed over the base unit and including a rotary grinding wheel;
a traverse moving device that can reciprocate the grinding wheel relative to the composite cam in the axial direction;
a plunge moving device that can move the grinding wheel relative to the composite cam in a direction crossing the axial direction; and
a control device that controls the workpiece rotating device, the traverse moving device, and the plunge moving device; wherein
the control device includes
a common base circle portion setting unit that obtains an angular range of the common base circle portion formed by at least the part of the outer peripheral surface of the first base circle portion and at least the part of the outer peripheral surface of the second base circle portion being flush with each other, based on the first cam lift data in which a lift with respect to a rotation angle of the first cam is set, and the second cam lift data in which a lift with respect to a rotation angle of the second cam is set,
a first cam grinding unit that controls the plunge moving device and the traverse moving device to move the grinding wheel to a position facing the outer peripheral surface of the first cam, and controls the workpiece rotating device and the plunge moving device to grind the first cam,
a second cam grinding unit that, after the grinding of the first cam, controls the plunge moving device and the traverse moving device to move the grinding wheel to a position facing the outer peripheral surface of the second cam, and controls the workpiece rotating device and the plunge moving device to grind the second cam, and
a common base circle portion traverse grinding unit that, after the grinding of the second cam, controls the traverse moving device to move the grinding wheel from a position of the second cam to a first position beyond a boundary between the first and second cams in a traverse direction in a first direction, controls the workpiece rotating device to rotate the composite cam within the angular range of the common base circle portion with respect to the grinding wheel to perform a first traverse grinding of the common base circle portion, controls the traverse moving device to move the grinding wheel from a position of the second cam to a second position beyond the boundary between the first and second cams in the traverse direction in a second direction opposite to the first direction, and controls the workpiece rotating device to rotate the composite cam within the angular range of the common base circle portion with respect to the grinding wheel to perform a second traverse grinding of the common base circle portion.

2. The cam grinding machine according to claim 1 , wherein
the grinding of the first cam using the first cam grinding unit comprises rough grinding and fine grinding, the grinding of the second cam using the second cam grinding unit comprises rough grinding, fine grinding, and spark-out, and the traverse grinding of the common base circle portion is performed after the spark-out of the second cam.

3. The cam grinding machine according to claim 2 , wherein
the common base circle portion traverse grinding unit of the control device moves the grinding wheel in the traverse direction in a range from the position of the second cam to a position of the first cam beyond the boundary between the first and second cams, and
the control device further includes
a first cam spark-out unit that, after the traverse grinding of the common base circle portion, controls the workpiece rotating device and the plunge moving device to perform spark-out of the first cam with the grinding wheel.

4. The cam grinding machine according to claim 1 , wherein
the traverse grinding in the common base circle portion traverse grinding unit is oscillation grinding in which the grinding wheel is reciprocated in the axial direction between the first and second cams.

5. A cam grinding method for grinding a composite cam, wherein
the composite cam includes
a first cam that has a first base circle portion having a first radius and a fixed lift height from a central axis to its outer peripheral surface, and a first cam portion having a varying lift height from the central axis to its outer peripheral surface, and
a second cam that has a second base circle portion having the first radius and the fixed lift height from the central axis to its outer peripheral surface, and a second cam portion having a varying lift height from the central axis to its outer peripheral surface,
the first cam and the second cam are coaxially disposed so as to adjoin each other in an axial direction,
the first cam and the second cam have different shapes, the shape of the first cam corresponding to first cam lift data and the shape of the second cam corresponding to second cam lift data, and
at least a part of the outer peripheral surface of the first base circle portion and at least a part of the outer peripheral surface of the second base circle portion are flush with each other to form a common base circle portion, the cam grinding method comprising:
a common base circle portion setting step of obtaining an angular range of the common base circle portion formed by at least the part of the outer peripheral surface of the first base circle portion and at least the part of the outer peripheral surface of the second base circle portion being flush with each other, based on the first cam lift data in which a lift with respect to a rotation angle of the first cam is set, and the second cam lift data in which a lift with respect to a rotation angle of the second cam is set;
a first cam grinding step of performing plunge grinding of the first cam with the grinding wheel based on the first cam lift data,
a second cam grinding step of, after the first cam grinding step, performing plunge grinding of the second cam with the grinding wheel based on the second cam lift data; and
a common base circle portion traverse grinding step of, after the second cam grinding step, moving the grinding wheel from a position of the second cam to a first position beyond a boundary between the first and second cams in a traverse direction in a first direction, a rotating the composite cam within the angular range of the common base circle portion with respect to the grinding wheel to perform a first traverse grinding of the common base circle portion, moving the grindi

Assignees

• Jtekt Corp

Inventors

• Mizutani Yoshihiro
• Abeta Satoshi
• Inoue Masaharu

Classifications

• F01L2305/00

  Valve arrangements comprising rollers · CPC title

• F01L2013/101

  Electromagnets · CPC title

• F01L2013/0052

  with cams provided on an axially slidable sleeve · CPC title

• F01L1/185

  Overhead end-pivot rocking arms · CPC title

• B24B19/12 Primary

  for grinding cams or camshafts · CPC title