Integrated cylinder finishing system

A system for finishing the cylindrical interior of a workpiece on a single machine is disclosed. The workpiece is mounted to allow access to its cylindrical interior from each end. A skiving tool is advanced into and through the cylindrical interior of the workpiece from one end to machine the cylindrical interior. As the skiving tool is operating, cutting oil is introduced into the cylindrical interior of the workpiece to entrain the chips generated by the skiving tool and flush the chips out through the second end of the workpiece. The cutting oil and entrained chips are deflected at the second end of the workpiece into a collector during operation of the skiving tool. The deflector is moveable to expose the second end of the workpiece when operation of the skiving tool is completed. A honing tool is advanced into and through the cylindrical interior of the workpiece from the second end thereof after the deflector has been moved and skiving completed. The honing tool removes imperfections in the cylindrical interior of the workpiece which had resulted from use of the skiving tool.

BACKGROUND OF THE INVENTION 
The present invention relates to an integrated system for finishing the 
cylindrical interior of a workpiece such as a hydraulic cylinder. 
A hydraulic or pneumatic cylinder is typically roughly formed in a steel 
mill by drawing a steel blank over a mandrel. As the steel is drawn over 
the mandrel, particulate matter often becomes embedded in the interior 
surfaces of the cylinder, and imperfections in the mandrel form 
corresponding imperfections on the interior of the cylinder. As a result, 
the interior surfaces of the cylinder must be finished so that the 
cylinder is usable for hydraulic or pneumatic applications. 
Perhaps the most common technique for finishing the interior surface of the 
cylinder is to hone the cylinder until smooth. This technique for 
finishing the interior of the cylinder is relatively inefficient because a 
hone is primarily designed to remove relatively small amounts of material 
so that the surface becomes quite smooth. 
A relatively large amount of time and effort is required to remove the 
rather substantial imperfections initially present in the cylinder blank. 
A far more efficient technique would be to initially cut the interior of 
the cylinder to its approximate final dimensions, before smoothing the 
interior surface with a honing tool. 
A technique has recently been developed for finishing the interior surfaces 
of a cylinder on a single machine. A skiving and roller burnishing tool, 
such as those shown in U.S. Pat. Nos. 3,795,957 and 4,133,089, finishes 
the interior of the cylinder in a single step. The skiving portion of the 
tool machines the interior of the cylinder, and the roller burnishing 
portion smoothes out the imperfections of the machining. 
This latter technique has the advantage of finishing the interior of the 
cylinder in a single operation, but has been found to have certain 
drawbacks. The roller burnishing forms a surface on the interior of the 
cylinder which is actually too smooth in most applications. The slight 
cross hatching provided by a honing tool in the conventional system is 
useful to allow oil to permeate the sidewalls of the cylinder, and the 
smooth walls formed by roller burnishing cannot provide this feature. As a 
result, the oil does not reach the seals, causing them to wear 
prematurely. In addition, roller burnishing compresses the material, which 
can cause laminations subject to potential delamination. Also, the 
combined skiving and roller burnishing tool required is relatively 
expensive and subject to failure. 
SUMMARY OF THE INVENTION 
The present invention provides a system for finishing the cylindrical 
interior of a workpiece on a single machine. The workpiece is mounted to 
allow access to its cylinderical interior from each end. A skiving tool is 
advanced into and through the cylindrical interior of the workpiece from 
one end to machine the cylindrical interior. As the skiving tool is 
operating, cutting oil is introduced into the cylindrical interior of the 
workpiece to entrain the chips generated by the skiving tool and flush the 
chips out through the second end of the workpiece. The cutting oil and 
entrained chips are deflected at the second end of the workpiece into a 
collector during operation of the skiving tool. The deflector is moveable 
to expose the second end of the workpiece when operation of the skiving 
tool is completed. A finishing tool such as a honing tool is advanced into 
and through the cylindrical interior of the workpiece from the second end 
thereof after the deflector has been moved and skiving completed. The 
honing tool removes imperfections in the cylindrical interior of the 
workpiece which had resulted from use of the skiving tool. 
The present invention thus allows a complete finishing of the interior of a 
cylinder, including separate skiving and honing steps, in a single setup. 
Skiving and honing steps are performed from opposite ends of the 
workpiece. During the skiving step, the deflector controls the flow of 
cutting oil so that it does not reach the honing tool. However, the 
deflector can be moved so that the honing step can readily be performed 
after completion of the skiving step. 
It is preferred that the honing tool be supported on a hone rest during 
operation of the skiving tool. After skiving has been completed, the hone 
rest, honing tool and hone drive are moved in unison so that the honing 
tool is advanced to a position proximate the tailstock supporting the 
second end of the workpiece. The hone drive and honing tool are then 
advanced in unison to move the honing tool from the hone rest into the 
tailstock. A chain then advances the hone drive to move the honing tool 
through the cylindrical interior of the workpiece. In this fashion, honing 
can readily be accomplished after the deflector has been moved out of the 
way to expose the second end of the cylinder. 
The novel features which are characteristic of the invention, as to 
organization and method of operation, together with further objects and 
advantages thereof, will be better understood from the following 
description considered in connection with the accompanying drawings in 
which a preferred embodiment of the invention is illustrated by way of 
example. It is to be expressly understood, however, that the drawings are 
for the purpose of illustration and description only and are not intended 
as a definition of the limits of the invention. description considered in 
connection with the accompanying drawings in which a preferred embodiment 
of the invention is illustrated by way of example. It is to be expressly 
understood, however, that the drawings are for the purpose of illustration 
and description only and are not intended as a definition of the limits of 
the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The apparatus 10 of the preferred embodiment of the present invention is 
illustrated generally by way of reference to FIG. 1. A unitary machine bed 
12 is mounted on a supporting floor 14 by posts 16. All components of the 
preferred embodiment are mounted on machine bed 12. 
A workpiece 18 having a hollow cylindrical interior, typically a hydraulic 
or pneumatic cylinder blank, is mounted on machine bed 12. A headstock 20 
attaches to one end of cylinder 18, and a tailstock 22 attaches to the 
other end. Headstock 20 and tailstock 22 may include shims 24 to adapt to 
different size cylinders, as indicated in connection with the tailstock. 
For large pieces, supporting members 26 may be used to provide further 
support for the cylinder. 
A skiving drive 28 is located at one end of machine bed 12. Skiving drive 
28 includes a motor 30 having a belt output 32 connected to gear train in 
housing 34. A skiving tool shaft 36 emanates from gear housing 34, and has 
a skiving tool 38 mounted on the end of the tool shaft toward cylinder 18. 
Headstock 20 has a hollow interior allowing skiving tool 38 to enter the 
cylinder 18 through the headstock. 
A hone drive 40 is located on the end of machine bed 12 opposite from 
skiving drive 28. Hone drive 40 also includes a motor 42 having a belt 
output 44 coupled to a gear train in housing 46. A honing tool shaft 48 
emanates from gear housing 46, and supports a honing tool 50 disposed a 
short distance from tailstock 22. 
A deflector shield 52 is pivotally mounted to tailstock 22 by pin 54. 
During operation of skiving tool 38, cutting oil is introduced into the 
interior of cylinder 18 through a passage 56 in headstock 20. The cutting 
oil flows through the interior of cylinder 18 and flushes the chips formed 
by the operation of skiving tool 38 out through tailstock 22. The cutting 
oil and entrained chips are deflected by deflector shield 52 into a 
collector 58 during the skiving operation. During the honing operation, as 
will be illustrated in more detail hereinafter, shield 52 is pivoted about 
pin connection 54 so that honing tool 50 can penetrate cylinder 18. 
When not in use, honing tool 50 is supported by a hone rest 60. Hone rest 
60 is mounted on a stand 62 by means of an adjustable support 64 to 
accommodate different size honing tools. A hydraulic cylinder 66 is 
adapted to provide transverse movement of hone rest 60. 
An endless chain 68 is attached to stand 62 by a pin 70. Chain 68 traverses 
a pair of idler sprockets 71, 72 mounted to machine bed 12. In addition, 
chain 68 traverses a pair of idler sprockets 73, 74 mounted on a frame 76 
which rides on rails 77 in gear housing 46. A drive pulley 78 engages 
chain 68 and is driven by a motor (not shown) within gear housing 46. A 
hydraulic cylinder 80 couples frame 76 to gear housing 46 so that the gear 
housing can be moved transversely relative to the frame. 
The operation of the system of the present invention is illustrated by way 
of reference to the schematic views of FIGS. 2A-C in sequence. 
Referring initially to FIG. 2A, the skiving tool 38 on shaft 36 is advanced 
into the cylindrical interior of cylinder 18. Shaft 36 rotates so that 
skiving tool 38 machines the interior of cylinder 18 as it passes through 
the cylinder. The chips caused by the machining of cylinder 18 are 
entrained in cutting oil flowing through the interior of the cylinder and 
out through tailstock 22. The cutting oil and entrained chips are 
deflected downwardly by shield 52 into collector 58. 
During the skiving operation, as depicted in FIG. 2A, honing tool 50 is 
located on hone rest 60 a distance away from the remainder of tailstock 22 
so that shield 52 can be in its downward position. Hone rest 60 is 
maintained in this position by hydraulic cylinder 66, which is in its 
extended configuration. Hydraulic cylinder 80 is in its contracted 
configuration during the skiving operation. 
After the skiving operation has been completed, deflector shield 52 is 
pivoted up and out of the way about pin 54, as depicted in FIG. 2B. 
Hydraulic cylinder 66 is contracted so that hone rest 60 is moved to a 
position proximate the remainder of tailstock 22. The motor driving 
sprocket 78 does not move so that chain 68 and frame 76 serve as a rigid 
member. Hydraulic cylinder 80 remains in its contracted configuration, and 
accordingly, hone drive 40, shaft 48 and honing tool 50 move as a unit 
together with hone rest 60 so that the entire honing system is advanced 
toward tailstock 22. 
After advancement of honing tool 50 and hone rest 60 to a position 
proximate tailstock 22, hydraulic cylinder 80 is extended as depicted in 
FIG. 2C. While hydraulic cylinder 80 is being extended, the motor 
controlling drive sprocket 78 does not move, and accordingly, chain 68 and 
frame 76 again act as a rigid member. Hone drive 40 is thus advanced 
another discrete step toward workpiece 18, while hone rest 60 remains 
stationary. As a result, honing tool 50 is moved off of hone rest 60, and 
penetrates the interior of tailstock 22. 
After hone head 50 has been moved into the interior of tailstock 22, the 
motor controlling drive sprocket 78 is actuated to move the honing tool 
into the interior of cylinder 18, as illustrated by dash lines. At the 
same time, motor 42 (see FIG. 1) is actuated to rotate honing tool shaft 
48, and the honing tool is advanced through cylinder 18 with a rotary 
motion to hone the interior of the cylinder. 
The sequence of steps illustrated hereinabove completely finishes the 
interior of cylinder 18. Both skiving and honing steps are provided so 
that the interior of the cylinder has slight crosshatching which 
facilitates oil distribution when the cylinder is put into use. All of the 
necessary operations are provided in a single machine system. 
While a preferred embodiment of the present invention has been illustrated 
in detail, it is apparent that modifications and adaptations of that 
embodiment will occur to those skilled in the art. However, it is to be 
expressly understood that such modifications and adaptations are within 
the spirit and scope of the present invention, as set forth in the 
following claims.