Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
  • B24D5/14—Zonally-graded wheels; Composite wheels comprising different abrasives
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B5/00—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor
  • B24B5/18—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor involving centreless means for supporting, guiding, floating or rotating work
  • B24B5/22—Machines or devices designed for grinding surfaces of revolution on work, including those which also grind adjacent plane surfaces; Accessories therefor involving centreless means for supporting, guiding, floating or rotating work for grinding cylindrical surfaces, e.g. on bolts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
  • B24D5/02—Wheels in one piece
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
  • B24D5/06—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor with inserted abrasive blocks, e.g. segmental
  • B24D5/066—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor with inserted abrasive blocks, e.g. segmental with segments mounted axially one against the other

Definitions

• the invention relates to a method and a grinding tool for high-precision centerless grinding of wavy workpieces with high surface quality, in particular piston pins, shock absorber parts and piston rods for hydraulic or pneumatic cylinders.
• high precision ground shaft parts with high surface quality wavy parts are to be understood in the context of this invention, the surface qualities and roundness tolerances about 1 ⁇ and below.
• shock absorber parts and piston rods for printing cylinder very high demands are placed on the shape tolerance and surface quality, resulting from the demand for an extremely reliable operation in use.
• sealing elements are provided in the shaft-shaped shock absorber parts in the shock absorbers, which slide on the surfaces of these shock absorber parts and must ensure reliable sealing from the inside to the outside as well as from the outside in.
• these high quality requirements result, inter alia, from the fact that with lower surface finishes and dimensional tolerances than those specified above, the operating characteristics are deteriorated.
• FIG. 4 The basic structure of such a centerless grinding machine is shown by way of example in FIG. 4 in a side view.
• the workpiece to be ground rests on a support, which is also referred to as a ruler, and is ground between each located in engagement with this tool grinding wheel and regulating wheel. Since the grinding wheel and regulating wheel rotate in opposite directions, the larger grinding wheel, generally larger in diameter than the regulating wheel, can grind the workpiece accordingly.
• Such stable centerless grinders are known, such as by the Applicant's JUPITER series machine.
• a good surface quality - is known for example in G 89 04 986.1 from juxtaposed and axially against each other braced grinding wheels to a grinding wheel package combined grinding tool the abrasive coating is formed differently by different grits one and the same abrasive from disk to disk.
• DE 295 16 264 U1 and DE 195 33 836 B4 describe a grinding wheel in which the physical properties of the lining constituents differ in the axial direction within their abrasive coating and thus on the grinding load, which is different in the axial direction are adjusted. This is achieved in that the concentration of the grains in the axial direction is variable, preferably linearly variable, is formed. This is intended to adapt the wear behavior of the abrasive coating to the oversize of the workpiece to be abraded.
• the object of the present invention is to provide a method and a grinding tool for implementing the method for high-precision centerless grinding of shaft parts, in particular piston pin, shock absorber parts and piston rods for hydraulic or pneumatic cylinders, achieved by means of which short cycle times and low machine costs and the avoidance of the negative accuracy affecting transposition operations can be avoided.
• This object is achieved with a grinding tool with the features according to claim 1 and with a method with the features according to claim 9.
• a grinding tool for highly accurate centerless grinding of wavy workpieces is provided.
• wave-shaped workpieces such as piston pins, shock absorber parts or piston rods for hydraulic or pneumatic cylinders
• this grinding tool according to the invention has two grinding regions, a conical grinding region and a cylindrical grinding region, the latter joining axially to the conical grinding region.
• the conical grinding area is designed so that it is provided for grinding a high removal rate, which is realized with a first abrasive coating.
• the cylindrical grinding portion is formed so as to be provided for grinding a high surface finish of the workpiece and having a second abrasive coating.
• the first and the second abrasive coating differ at least with regard to their respective abrasives.
• binding and lining specification of the respective abrasive coating of the first and the second abrasive coating are different.
• the abrasive, bond and coating specification and, if appropriate, even further physical or chemical properties of the first and the second abrasive coating may be different. It is particularly preferred if CBN is used as abrasive for the first abrasive coating and diamond as abrasive for the second abrasive coating.
• Different abrasives are to be understood as meaning those which, due to their different chemical composition, have different abrading properties.
• the grinding tool with its conical and cylindrical grinding area is intended to move the workpiece past a stationary grinding tool.
• a wave-shaped workpiece is ground in a continuous process. This means that the workpiece is finish ground when once again covering the movement path which corresponds to the grinding tool width.
• Finished grinding in this context means that the wave-shaped workpiece is finished with the highest accuracy in terms of dimensional accuracy, dimensional stability and surface quality.
• the preferred embodiment of the second abrasive coating with the abrasive diamond surprisingly brings the effect of the most accurate surface finish, and indeed on a wavy workpiece even from usually normal steel. For grinding normal Steel is, according to the knowledge of one of ordinary skill in the art, unsuitable for an abrasive diamond.
• the grinding tool is ground using the tool according to the invention in a continuous process or in centerless grinding
• the grinding tool is preferably made up of at least two partial grinding wheels, of which the first part grinding wheel forms the conical grinding area and the second part grinding wheel forms the cylindrical grinding area, wherein both partial grinding wheels are preferably braced with each other so that they without formation of a grinding gap, ie gapless, contiguous.
• braced is to be understood as being almost adjacent to one another
• these are braced with their basic bodies on the grinding spindle in such a way that their main bodies touch, but the abrasive linings in the braced condition of the partial grinding wheels A small distance of, for example, about 0.2 to 0.3 mm to each other .This is necessary so that no lateral stresses are introduced into the abrasive layers in the clamped state.
• An essential advantage of such a grinding tool according to the invention is that for the production of the wave-shaped workpiece in maximum accuracy reduced cycle times and thus a significant cost savings and in total an improvement in cost-effectiveness, which is particularly important in large quantities by means of the grinding tool according to the invention workpieces of importance is.
• the conical grinding region of the grinding tool is designed for high machining performance, while the second, cylindrical grinding region is preferably designed so that either only a very small Schleifabtrag or no significant Schleifabtrag is realized, but only a Feinstschleifen or even a surface smoothing by polishing in the sense a so-called Ausfunkreaes takes place.
• the grinding tool is designed as a grinding wheel package, in which the individual, the grinding tool constituting partial grinding wheels together or against each other are mutually braced and in which the conical grinding area is formed by at least two first part grinding wheels.
• the advantage that the conical grinding region is constructed by at least two first partial grinding wheels is that on the one hand both first partial grinding wheels can have a different taper angle and on the other hand can be produced and assembled better.
• the grinding tool in one piece, so that the first and the second abrasive coating are arranged on the base body axially adjacent to each other so that no gap is present, but both abrasive coatings directly adjoin one another without a gap present and without a step formed is.
• a method of high accuracy centerless grinding for a wavy workpiece in particular piston pins, shock absorber parts or piston rods for hydraulic or pneumatic cylinders.
• a single grinding tool having a conical grinding area with a
• the first abrasive is CBN and grinds the gauge with a high chip volume per unit time and the second abrasive is diamond and is used to that at most a very small, in any case significantly lower cutting volume is ground than that which is ground with the CBN grinding area.
• the diamond grinding area for achieving a very precise surface quality can also be used with preference for the fact that the machining volume to be ground in the manner of superfishing is very low or even approaches zero, for example in the sense of sparking off, so that only smoothing, Polishing is performed.
• Superfinishing is to be understood in the context of this invention, a Feinstschleifen.
• Figure 1 the basic arrangement of grinding wheel, regulating wheel and grinding wavy workpiece for centerless grinding according to the invention
• Figure 2 the arrangement of a regulating wheel with inclined axis to achieve a feed movement for the wavy workpiece in Centerless grinding with a grinding tool according to the invention
• Figure 3A a grinding wheel with a conical and a cylindrical grinding area for centerless grinding in the run-through method according to the invention
• FIG. 3B shows a grinding wheel according to FIG. 3A, but with two conical grinding regions of different cone angle according to the invention
• FIG. 4 is a schematic representation of a centerless grinding arrangement in side view according to the prior art.
• FIG. 5 shows a grinding tool according to the invention for carrying out a grinding method according to the invention.
• FIG. 1 shows the basic structure of a grinding machine for a continuous centerless grinding with a grinding tool 1 according to the invention.
• the workpiece 16 rests on a guide ruler, not shown here, and is conveyed through the grinding gap between the grinding tool 1 and the regulating wheel 15 during grinding.
• the grinding tool 1 has - as well as the regulating wheel - two grinding areas 3, 4 and rotates about its axis of rotation 2.
• the grinding tool 1 and the regulating wheel 15 rotate in opposite directions and promote during grinding the workpiece 16 in a continuous process through the grinding gap between the grinding tool 1 and regulating wheel 15 according to the indicated arrow through.
• the workpiece 16 is likewise set in rotation by the engagement of grinding tool 1 and regulating wheel 15.
• the respective grinding portions 3 of the grinding tool 1 and 15a of the regulating wheel 15 are tapered, and the grinding portion 4 of the grinding tool 1 and the grinding portion 15b of the regulating wheel 15 are cylindrical or nearly cylindrical.
• the regulating wheel 15 is preferably designed as a one-piece regulating wheel (corundum grinding wheel with rubber binding). It is dressable in shape, preferably with a diamond fleece.
• FIG. 2 shows a view of a regulating wheel 15 from the direction of the grinding tool 1 (without its representation) with a regulating wheel 15 pivoted into the centerless loop for grinding. Otherwise, the basic construction corresponds to that explained in FIG.
• the inclination of the regulating wheel 15 causes a conveyance of the workpiece 16 through the (not shown) grinding gap between the grinding tool 1 and regulating wheel 15th
• FIG. 3A the principal grinding wheel contour with the grinding wheel region 3 with a conically contoured contour (abrasive coating 13) and the grinding wheel region 4 with a cylindrically aligned contour (abrasive coating 14) are shown in exaggerated cone angle.
• FIG. 3B shows a grinding tool 1 as a grinding wheel package, which is composed of three partial grinding wheels 5, 6, 9.
• the cone angles ⁇ , ⁇ of the partial grinding wheels 5, 6 are shown in an exaggerated representation.
• Trained as a grinding wheel package grinding tool 1 has two grinding areas 3a, 3b, which are tapered and each have a different cone angle ⁇ and ß.
• the conical contour with the grinding areas 3a, 3b forms the grinding wheel inlet, and the cylindrical contour with the grinding area 4 forms the part of the grinding tool 1 with which the surface quality of the wave-shaped workpiece is achieved.
• the width of the respective partial grinding wheels 5, 6, 9 can be chosen differently depending on the purpose. For the individual partial grinding wheels 5, 6, the grain size can also be different in order to achieve optimum adaptation to the respective grinding tasks.
• the grain concentration in the abrasive coating of the respective partial grinding wheels 5, 6 vary, preferably linearly increasing or decreasing in the axial direction.
• the cone angles .alpha. And .beta. Can also be varied depending on the allowance and thus the cutting volume to be ground as a function of, for example, the material properties. Irrespective of whether the grinding tool 1 consists of a single basic carrier or is composed of a plurality of individual partial grinding wheels to form a grinding wheel package, NEN the respective widths of the grinding areas 3a, 3b, 4 are adapted by the dressing of the grinding tool 1 to the technological requirements.
• ⁇ is greater than ß, so that during grinding, the first 5 of the two first part grinding wheels 5, 6 removes a larger Zerspanvolumen than the second 6 of the first two part grinding wheels 5, 6th
• Figure 4 shows a schematic representation of a continuous centerless grinding in a side view of such a grinding machine.
• a grinding gap is defined, in which the workpiece 16 to be ground is supported on a guide or support ruler 17 during grinding.
• X1 and X2 show the infeed directions for the grinding spindle X1 and the control spindle X2. This basic structure is known and is used for continuous centerless grinding machines in this form.
• FIG. 5 shows a grinding tool 1 according to the invention.
• This grinding tool 1 has an inlet region, which is tapered and, in the present exemplary embodiment, is formed from four individual partial grinding wheels 5, 6, 7, 8.
• the conical grinding area accordingly consists of four grinding areas 3a, 3b, 3c, 3d and represents the workpiece (not shown here) the inlet area, wherein all four partial grinding wheels 5, 6, 7, 8 have the same cone angle.
• the four partial grinding wheels 5, 6, 7, 8 all have the same abrasive coating 13, which has ceramic bonded CBN as abrasive.
• the specification of the grinding lining of the respective partial grinding wheel can already be selected differently.
• the specifications of the respective abrasive coating such as its grain size, concentration, concentration distribution, bond, etc., as well as the respective cone angle can be different.
• the first part grinding wheel or the plurality of first part grinding wheels generally has a larger cone angle than the subsequent part grinding wheels. The smaller the cone angle of a partial grinding wheel, the lower the cutting volume to be ground by this partial grinding wheel.
• the grinding tool according to the invention to set the grinding wheel specifications optimally to the result to be ground.
• the first two partial grinding wheels can preferably be designed for very high machining performance, the two following partial machining
• grinding wheels with a smaller cone angle have a lower cutting performance but are already designed for better dimensional accuracy and surface quality.
• the difference in diameter of the conically-trued partial grinding wheels has at least the diameter-related grinding allowance of the workpiece.
• the conicity of the partial grinding wheels can be dressed by means of a diamond wheel and, depending on the application, can be easily changed by means of a CNC-controlled dressing program stored in a grinding machine provided with the grinding tool according to the invention.
• an abrasive an abrasive with a synthetic resin bond can be provided for the part-grinding wheels with conical contour instead of ceramically bonded CBN.
• the partial grinding wheels 9, 10 shown in FIG. 5 have a cylindrical shape. They are dressed in such a cylindrical shape and therefore have a constant or nearly constant diameter.
• the surface on the wave-shaped workpiece which is not shown in Figure 5 for the sake of simplicity, feinstgeschlichtet or subjected to superfinishing, with the two grinding areas 4a, 4b.
• the grain size or the concentration of the diamond grains may be formed varying depending on the respective grinding task, z. B. in the axial direction linearly increasing or decreasing.
• the partial grinding wheels 9, 10 are diamond grinding wheels with a ceramic bond or a synthetic resin bond.
• the structure described in Figure 5 it is possible, for example, to dress the entire grinding wheel package.
• the superfinishing or Feinstschleifen exporting part-grinding wheels 9, 10 in the grinding tool 1, which is characterized by the part-grinding wheels 5, 6, 7, 8 significantly for the material removal of the allowance on the workpiece it is possible to complete the To save the process of superfinishing on another machine or another station on a machine.
• the grinding tool according to the invention are diamond grinding wheels with a ceramic bond or a synthetic resin bond.
• the arrow shown in Figure 5 below shows the conveying direction of the workpiece relative to the grinding tool. 1
• the diamond part grinding wheels 9, 10 preceded by CBN part grinding wheels, which - as already mentioned - mainly machine the material of the oversize of the workpiece, and it becomes the dimensional and dimensional accuracy at least roughly produced.
• the diamond part grinding wheels 9, 10 are responsible for the dimensional and shape accuracy and for the production of the required high surface quality, as it were, for the final grinding Grinding Spindle 1 1
• a number of grinding wheels with different physical properties are clamped together by means of a clamping flange 1 2.
• highly accurate dimensional and dimensional stability as well as surface finish can be achieved
• the ability to cut large volumes and at the same time achieve a high surface quality offers the possibility of large-scale technical applications with the highest quality requirements.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Grinding Of Cylindrical And Plane Surfaces (AREA)

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• 2013
  • 2013-02-15 DE DE102013202509.2A patent/DE102013202509A1/de not_active Withdrawn
• 2014
  • 2014-02-10 JP JP2015557393A patent/JP2016510265A/ja not_active Withdrawn
  • 2014-02-10 KR KR1020157024343A patent/KR20150118982A/ko not_active Application Discontinuation
  • 2014-02-10 EP EP14713768.1A patent/EP2956271A1/de not_active Withdrawn
  • 2014-02-10 CN CN201480008729.1A patent/CN105121091A/zh active Pending
  • 2014-02-10 WO PCT/EP2014/052567 patent/WO2014124907A1/de active Application Filing
  • 2014-02-10 US US14/764,428 patent/US9486895B2/en not_active Expired - Fee Related
  • 2014-02-10 RU RU2015139134A patent/RU2015139134A/ru unknown

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