Honing method and inner cam with C-shaped cross section

1. A honing method for grinding an inner circumferential surface of a workpiece comprising an arcuately shaped inner circumferential surface with a central axis in which a discontinuous portion is provided between both ends thereof in a circumferential direction, comprising:

a fixing step comprising:

stacking a plurality of the workpieces along a stacking axis forming a stack with a first of the workpieces on an end side, a second of the workpieces on an another end side, and at least one of the workpieces stacked therebetween, and

fixing relative positions of the plurality of workpieces by fixing the first of the workpieces on the end side positioned with the central axis coincident with the stacking axis and the discontinuous portion oriented in a first direction relative to the stacking axis, fixing the second of the workpieces on the another end side positioned with the central axis coincident with the stacking axis and the discontinuous portion oriented in the first direction relative to the stacking axis, and fixing the at least one of the workpieces stacked therebetween positioned with the central axis coincident with the stacking axis and the discontinuous portion oriented in a second direction relative to the stacking axis, wherein the first direction and second direction are opposite relative to each other; and

a grinding step of simultaneously grinding the inner circumferential surfaces of the plurality of workpieces by rotating, about the stacking axis, a honing head on which a plurality of grindstones are mounted at intervals along the circumferential direction;

wherein, a machining load is applied in the grinding step to simultaneously to:

create a first force in the first of the workpieces on the end side in a primary load direction away from the discontinuous portion,

create a second force in the second of the workpieces on the another end side in the primary load direction, and

create a third force in the at least one of the workpieces stacked therebetween in a secondary load direction opposite to the primary load direction.

2. A honing method for grinding an inner circumferential surface of a workpiece comprising an arcuately shaped inner circumferential surface with a central axis in which a discontinuous portion is provided between both ends thereof in a circumferential direction, comprising:

a fixing step comprising:

stacking a plurality of the workpieces along a stacking axis forming a stack with a first group of the workpieces stacked on an end side, a second group of the workpieces stacked on an another end side, and a third group of the workpieces stacked therebetween, and

fixing relative positions of the plurality of workpieces by fixing the first group of the workpieces stacked on the end side positioned with the central axes of the first group of the workpieces coincident with the stacking axis and the discontinuous portions of the first group of the workpieces oriented in a first direction relative to the stacking axis, fixing the second group of the workpieces stacked on the another end side positioned with the central axes of the second group of the workpieces coincident with the stacking axis and the discontinuous portions of the second group of the workpieces oriented in the first direction relative to the stacking axis, and fixing the third group of the workpieces stacked the rebetween positioned with the central axes of the third group of the workpieces coincident with the stacking axis and the discontinuous portions of the third group of the workpieces oriented in a second direction relative to the stacking axis, wherein the first direction and second direction are opposite relative to each other; and

a grinding step of simultaneously grinding the inner circumferential surfaces of the plurality of workpieces by rotating, about the stacking axis, a honing head on which a plurality of grindstones are mounted at intervals along the circumferential direction;

wherein, a machining load is applied in the grinding step to simultaneously to:

create a first force in the first group of the workpieces on the end side in a primary load direction away from the discontinuous portion,

create a second force in the second group of the workpieces on the another end side in the primary load direction, and

create a third force in the third group of the workpieces stacked therebetween in a secondary load direction opposite to the primary load direction.

3. The honing method according to claim 1 , wherein the plurality of grindstones are mounted at intervals that are maximally spaced apart along the circumferential direction wherein a distance between at least two adjacently arranged grindstones is smaller than a distance between the both ends having the discontinuous portion interposed therebetween.

4. The honing method according to claim 1 , wherein the workpiece is an inner cam having a substantially C-shaped cross section in which an opening is provided between both ends in the circumferential direction.

5. The honing method according to claim 2 , wherein: in the fixing step, a total number of the plurality of the workpieces is an even number, a total number of the first group of workpieces, a total number of the second group of workpieces is equal, and a total number of the third group of workpieces is equal to a collective number of the first group of workpieces and the second group of workpieces, and

wherein the first direction and second direction differ by 180 degrees relative to each other.