Honing tool and fine machining method using the honing tool

Abstract

A honing tool (100) for machining an inner face (322) of a bore (320) in a workpiece (300) with the aid of at least one honing operation comprises a tool body (110) that defines a tool axis, and an expandable cutting group (330), attached to the tool body, having a plurality of radially feedable cutting material body carriers (150) that each cover a circumferential angle range and are feedable radially with respect to the tool axis by means of a cutting group feeding system assigned to the cutting group. Each cutting material body carrier carries, on its radial outer side, a plurality of narrow cutting material bodies (140) configured as cutting material strips (140-1, 140-2, 140-3, 440-1, 440-2) that are narrow in the circumferential direction and have a width in the circumferential direction that is small compared with the axial length of the cutting material strips. The cutting material bodies are arranged at a mutual spacing from one another. An elastically resilient intermediate layer (160) is arranged in an intermediate space between a cutting material body (140) and the cutting material body carrier (150) carrying the cutting material body, said intermediate layer (160) filling the intermediate space between the cutting material body and the cutting material body carrier. A preferred field of application is the honing of cylinder surfaces in the production of cylinder blocks or cylinder liners for reciprocating piston engines.

1 . A honing tool for machining an inner face of a bore in a workpiece with the aid of at least one honing operation, in particular for honing cylinder surfaces in the production of cylinder blocks or cylinder liners for reciprocating piston engines, comprising:
 a tool body that defines a tool axis;   an expandable cutting group, attached to the tool body, having a plurality of radially feedable cutting material body carriers that each cover a circumferential angle range and are feedable radially with respect to the tool axis by means of a cutting group feeding system assigned to the cutting group, wherein   each cutting material body carrier carries, on its radial outer side, a plurality of narrow cutting material bodies configured as cutting material strips that are narrow in the circumferential direction and have a width (BS) in the circumferential direction that is small compared with the axial length (LS) of the cutting material strips, wherein the cutting material bodies are arranged at a mutual spacing from one another,   wherein   an elastically resilient intermediate layer is arranged in an intermediate space between a cutting material body and the cutting material body carrier carrying the cutting material body, said intermediate layer filling the intermediate space between the cutting material body and the cutting material body carrier.   
     
     
         2 . The honing tool as claimed in  claim 1 , wherein the intermediate layer has a layer thickness (SD) in the range from 0.1 mm to 2 mm, in particular in the range from 0.5 mm to 1.5 mm. 
     
     
         3 . The honing tool as claimed in  claim 1 , wherein a Shore hardness of the intermediate layer is in the range from 70 Shore A to 95 Shore A. 
     
     
         4 . The honing tool as claimed in  claim 1 , wherein the intermediate layer has a layer made of an elastomer, in particular of a rubber-elastic polyurethane elastomer. 
     
     
         5 . The honing tool as claimed in  claim 1 , wherein the intermediate layer has been vulcanized directly onto a contact face on the cutting material body or the outer face of the cutting material body carrier element. 
     
     
         6 . The honing tool as claimed in  claim 1 , wherein the intermediate layer has a first layer and at least one second layer connected extensively thereto, wherein the first layer is a layer made of an elastomer and the second layer is an adhesive layer connected extensively to the first layer. 
     
     
         7 . The honing tool as claimed in  claim 1 , wherein the cutting group has an axial length (LS), measured in the axial direction, that is less than an effective outside diameter (AD) of the cutting group with cutting material bodies fully retracted. 
     
     
         8 . The honing tool as claimed in  claim 7 , wherein the honing tool has at least one of the following properties:
 (i) the axial length (LS) of the cutting material bodies is less than 40% of the effective outside diameter of the cutting group;   (ii) the axial length (LS) of the cutting material bodies is in the range from 5 mm to 40 mm;   (iii) the axial length (LS) of the cutting material bodies is less than 20% of the bore length of the bore;   (iv) the axial length (LS) of the cutting material bodies is in the range from 20% to 50% of the bore diameter;   (v) an aspect ratio between the axial length (LS) and the width (BS) of the cutting material bodies is in the range from 4:1 to 20:1.   
     
     
         9 . The honing tool as claimed in  claim 1 , wherein the cutting group has at least three cutting material body carriers, which are arranged such that machining forces over the entire effective outside diameter, available by expansion, of the honing tool are able to be distributed uniformly around the circumference of the cutting group, wherein the cutting group has preferably exactly four, exactly six or exactly eight cutting material body carriers of the same or different circumferential width. 
     
     
         10 . The honing tool as claimed in  claim 1 , wherein the honing tool is designed as a honing tool with double expansion, wherein the cutting group has a first group of cutting material body carriers and a second group of cutting material body carriers that is feedable independently of the first group. 
     
     
         11 . The honing tool as claimed in  claim 10 , wherein the cutting material bodies of the first group differ from the cutting material bodies of the second group, preferably in that the cutting material bodies of the two groups have different widths and/or have been applied to the cutting material body carriers with different circumferential spacings and/or a different pitch, and/or in that the cutting material bodies of one of the groups are provided with coarser grain for rougher machining and the cutting material bodies of the other group are provided with finer grain for finer machining. 
     
     
         12 . The honing tool as claimed in  claim 10 , wherein, in the first group, the cutting material bodies are fastened directly to the associated cutting material body carrier without interposition of an elastic intermediate layer and are connected rigidly to the cutting material body carrier, and in the second group, the cutting material bodies are fastened to the associated cutting material body carrier in an individually resilient manner via an elastic intermediate layer. 
     
     
         13 . A fine machining method for machining the inner face of a bore in a workpiece, in particular for fine machining cylinder surfaces in the production of cylinder blocks or cylinder liners for reciprocating piston engines,
 wherein the fine machining method comprises at least one honing operation in which an expandable honing tool is moved up and down within the bore in order to create a reciprocating movement in the axial direction of the bore and at the same time is rotated in order to create a rotary movement superimposed on the reciprocating movement,   wherein   a honing tool having the features of at least one of the preceding claims is used in the honing operation.   
     
     
         14 . The fine machining method as claimed in  claim 13 , wherein, before the start of the honing operation, a bore shape that differs from the circular-cylindrical shape is created by fine boring and/or honing, and in that a honing operation for creating the desired surface structure on the bore inner face is carried out using the honing tool, substantially without changing the macro shape of the bore. 
     
     
         15 . The fine machining method as claimed in  claim 13 , wherein a honing tool with double expansion is used, in which a cutting group of the honing tool has a first group of cutting material body carriers and a second group of cutting material body carriers that is feedable independently of the first group, wherein in each case the cutting material body carriers of one group are radially fed and retracted jointly, wherein a prior first honing operation is carried out with the first group, this group is then retracted, the other group is radially fed, and then a following second honing operation is carried out with the cutting material bodies of the second group. 
     
     
         16 . The fine machining method as claimed in  claim 13 , wherein the first group has cutting material bodies rigidly connected to the cutting material body carriers, and the first honing operation is a contour honing operation, and in that the second group is provided with cutting material bodies that are fastened to the associated cutting material body carriers in an elastically resilient manner via an elastically resilient intermediate layer, wherein the second honing operation is a tracking honing operation.