JP2012187682A - Grinding tool for honing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding tool which is not only with excellent discharging efficiency of grinding powder of slits without reducing the rigidity of a holder body but also with an improved cooling effect on places of a processed surface where cooling is required by achieving fine adjustments of a discharging position of coolants on the slits.SOLUTION: The grinding tool includes the columnar holder body with several slits in the peripheral direction, a tapered cone contained coaxially with the holder body, hone shoes supported by the cone and contained inside each of the several slits, and hones installed on the shoes and projected from the holder body in the radius direction. The shoes are capable of freely moving by the movement of the cone in the shaft direction. The holder body is provided with a coolant flow entrance which supplies the coolant into the holder body and several discharging grooves formed on the slits which discharge the coolant flowed into the holder body. The discharging grooves are dented in a front surface of the slits in a tool rotating direction.

Description

  The present invention relates to a honing grinding tool with improved properties.

  A grinding tool called a honing holder is used for grinding a member having a recessed oil sump groove such as a cylinder bore of an automobile internal combustion engine. In this grinding tool, a plurality of grindstones are attached to slits formed in a rotatable honing holder main body via holders (grinding shoe) that radiate from the rotation shaft, and the holder main body is rotated and reciprocated in the axial direction. The inner peripheral surface of the workpiece is ground by moving the workpiece.

  In a conventional honing holder, a technique for supplying coolant to a grinding surface is known in order to cool heat generated by friction between a grindstone and a workpiece in a roughing process and a finishing process.

  Among them, the coolant supply means is not provided separately from the honing holder, but is integrated, the supply channel is formed inside the honing holder body, the coolant is circulated, and the coolant discharge port is formed on the processing surface of the holder body And the technique of supplying to a grinding surface from here is known.

  However, since the coolant discharge port is further provided independently of the slit holding the grindstone, the problem that the rigidity of the holder main body is reduced and the coolant cannot always be appropriately supplied to the processing surface. There was a problem.

  In order to solve such a problem, a technique is known in which a coolant is discharged from a gap between the grindstone and the holder main body without using a coolant discharge port independently, so that the slit holding the grindstone and the coolant discharge port are combined. (For example, refer to Patent Documents 1 and 2).

  In the honing holder described in Patent Document 1, a coolant flow path is formed inside a tapered cone provided in the holder main body for adjusting the advancing and retreating of the grindstone in the radial direction of the rotation axis. The coolant supplied from is discharged from the gap between the slit of the holder body and the grindstone to the external machining surface via this flow path.

  Further, in the honing holder described in Patent Document 2, the coolant flow path similarly passes through the honing holder, but the coolant flow path formed of a spiral groove is formed on the inner peripheral surface of the holder main body, The coolant is supplied to the processing surface by this flow path.

  According to these techniques, since the coolant is discharged from the slit near the processing surface, the cooling effect can be improved as compared with the conventional honing holder, and there is no need to provide an independent coolant discharge port. It can suppress that the rigidity of a holder main body falls. Furthermore, the grinding powder that has entered the inside of the holder main body through the gap between the holder main body and the grindstone in the slit can be discharged to the outside.

Japanese Patent Publication No. 7-4759 Japanese Patent No. 4119067

  However, in the honing holder described in any of the above-mentioned patent documents, the coolant is merely discharged from the slit holding the grindstone, and the slit is not always appropriate for the processing surface. The fine adjustment of the discharge position was not possible, and the device for adjusting the discharge flow rate was not devised.

  The invention of the present application has been made in view of the above situation, and it is necessary to cool the processed surface as well as to reduce the grinding powder from the slit without reducing the rigidity of the honing holder body. An object of the present invention is to provide a grinding tool that improves the cooling effect on the machined surface by enabling fine adjustment of the coolant discharge position in the slit.

  The present invention relates to a cylindrical holder body having a plurality of slits in the circumferential direction, a tapered cone contained coaxially with the holder body, a grinding wheel shoe supported by the tapered cone and contained in each of the plurality of slits, and a grinding stone A grinding tool that is attached to the shoe and includes a grindstone that protrudes in the radial direction from the holder main body, and the grindstone shoe can be advanced and retracted in the radial direction by advancing and retreating in the axial direction of the taper cone. A coolant inlet for supplying coolant and a plurality of discharge grooves formed in a slit for discharging the coolant that has flowed into the holder body, and the discharge grooves are engraved on the front surface of the slit in the tool rotation direction It is characterized by being.

  In this invention, it is set as the preferable aspect that the sum total of the cross-sectional area of a discharge groove is smaller than the cross-sectional area of an inflow port.

  Further, in the present invention, a plurality of grinding wheels for roughing and a plurality of grinding stones for finishing are provided, and a cross-sectional area of a groove formed in a slit supported by the grinding stone for roughing, and a grinding wheel for finishing A preferred embodiment is that the cross-sectional areas of the grooves formed in the slit to be supported are different.

  In the conventional grinding tool, since the coolant is discharged from the entire slit, the coolant has been supplied to the workpiece on the upstream side in the rotational direction of the grindstone, which has not yet been ground, and wasted. . However, according to the grinding tool of the present invention, since the coolant discharge groove is engraved on the front surface in the tool rotation direction in the slit, the coolant discharge groove is always larger than the grindstone when the tool rotates. Since it is on the upstream side, there is an effect that it is possible to supply the coolant only to the processed surface of the workpiece that needs to be cooled immediately after the processing that is ground by the grindstone. Further, since the slit is provided with a groove, the rigidity of the holder body can be increased as compared with a conventional grinding tool in which a discharge hole is separately provided in the holder body.

  Also, if the sum of the cross-sectional areas of the discharge grooves is made smaller than the cross-sectional area of the inlet when flowing into the holder body, the coolant flow rate in the discharge grooves will increase, so that the abrasive powder entering the holder body can be discharged. It is possible to improve.

  Further, when the cross-sectional area of the discharge groove is different between the slit of the roughing grindstone and the slit of the finishing grindstone, the optimum coolant flow rate can be set for each target processing.

It is a perspective view which shows the grinding tool of this invention. It is a perspective view which shows the holder main body of the grinding tool of this invention. It is a perspective view which shows the outer side taper cone of the grinding tool of this invention. It is a perspective view which shows the inner side taper cone of the grinding tool of this invention. It is the sectional view on the AA line in FIG. It is sectional drawing which shows the holder main body of the grinding tool of this invention. It is sectional drawing which shows the outer side taper cone of the grinding tool of this invention, (b) is CC sectional view taken on the line of (a). It is sectional drawing which shows the inner side taper cone of the grinding tool of this invention, (b) is the DD sectional view taken on the line of (a).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Configuration of Grinding Tool FIG. 1 is a perspective view of a grinding tool H of the present invention, and FIGS. 2 to 4 are detailed enlarged views of each member (holder body, outer tapered cone, inner tapered cone), FIGS. These are cross-sectional views thereof. Further, FIG. 5 is a perspective view of the assembled state.

  The grinding tool H includes a holder main body 10 having a cylindrical head for grinding, an outer tapered cone 20 coaxially included in the holder main body 10, and an inner tapered cone included coaxially in the outer tapered cone 20. 30. A plurality of slits 11a and 11b are formed in the cylindrical portion 15 of the holder main body 10 in the circumferential direction, and a grindstone portion 40 and 41 are included in each of the slits 11a and 11b so as to slightly protrude in the radial direction. . The base end side 16 of the holder main body 10 is connected to a known rotation mechanism (not shown), and the workpiece is ground by rotating the holder main body 10 itself.

  The grindstone portion includes a rough grindstone portion 40 for rough grinding and a finish grindstone portion 41 for finishing, and the rough grindstone 40a and the finish grindstone 41a are respectively supported by the grindstone shoes 40b and 41b (hereinafter, referred to as “the grindstone”). They are distinguished only by reference numerals and may simply be abbreviated as “whetstone portions 40, 41” and “whetstones 40a, 41a”). In FIG. 2, some of the grindstone portions are shown as representatives, but actually, as indicated by the reference numerals, the grindstone portions 40 and 41 are included in all the slits 11 a and 11 b, respectively.

  When viewed in a cross section in the radial direction, as shown in FIG. 2, the grindstone portion 41 is arranged in a cross shape, and the grindstone portion 40 is arranged so as to be adjacent to both sides of the grindstone portion 41 or one of them. However, the arrangement of the rough grindstone and the finishing grindstone in the present invention is not limited to this order.

  Among these grindstones, the grindstone portion 40 has a relatively short leg grindstone shoe 40 b, and the grindstone shoe 40 b penetrates the slit 11 a of the holder main body 10, and the bottom portion is tapered by the tapered portions 22 a and 22 b of the outer tapered cone 20. The grindstone shoe engaging portion 40c is supported and engaged with the engaging portion 26 of the outer tapered cone 20 to prevent the slit 11a from falling off.

  The grindstone portion 41 has a relatively long leg grindstone shoe 41 b. The grindstone shoe 41 b penetrates the slit 11 b of the holder body 10, and further penetrates the through hole 21 of the outer tapered cone 20, and the inner tapered cone 30. The bottom portions are supported by the taper portions 31a and 31b, and the grindstone shoe engaging portion 41c engages with the engaging portion 34 of the inner tapered cone 30 to prevent the slit 11b from falling off.

  As shown in FIGS. 7A and 8A, the grindstone shoe 40b is in contact with the tapered portions 22a and 22b of the outer tapered cone 20, and the grindstone shoe 41b is a tapered portion 31a and 31b of the inner tapered cone 30. Abut. Furthermore, although the grindstone shoes 40b and 41b are free in the radial direction by fitting into the slits 11a and 11b, the movement in the axial direction is restricted.

  Therefore, when the outer tapered cone 20 and / or the inner tapered cone 30 are slid in the axial direction, the grindstone portion can be moved forward and backward in the radial direction by sliding between the tapered portion and the grindstone shoe bottom. Specifically, the grindstone portion can be moved radially outward when the taper cone is slid in the upward direction in the drawing, and radially inward when the taper cone is slid downward in the drawing. Thereby, the protrusion amount to the radial direction of a grindstone part can be adjusted.

  Further, since the holder main body 10, the outer tapered cone 20 and the inner tapered cone 30 are independent from each other, only the outer grindstone portion 40 is finished by sliding only the outer tapered cone 20, and only the inner tapered cone 30 is slid. Only the grindstone 41 can be moved independently.

  The inner peripheral surface 14 of the holder body 10 shown in FIG. 5 and the outer peripheral surface 24 of the outer tapered cone 20 shown in FIG. 9 are also the inner peripheral surface 25 of the outer tapered cone 20 and the outer peripheral surface 33 of the inner tapered cone 30 shown in FIG. The inner diameter and the outer diameter are adjusted so that a gap is formed between the two in the assembled state.

  As shown in FIG. 6, a coolant inlet 13 is formed in the flange portion of the holder body 10, and the supplied coolant passes through the holder body 10 as will be described later via the coolant inlet 13. The slits 11a and 11b containing the grindstone are discharged to the outside of the holder body 10.

  The slits 11a and 11b are formed with discharge grooves 12a and 12b, respectively, and when the coolant is discharged from the slit, the coolant is mainly discharged from the discharge grooves 12a and 12b. At this time, in the grinding tool of the present invention, as shown in FIGS. 1 and 2, the slits 12a and 12b are formed on the front surface with respect to the rotation direction B of the grinding tool indicated by an arrow on the base end side 16 of the grinding tool. It is only characterized by being engraved.

  Thus, since the discharge grooves 12a and 12b are engraved only on the front surfaces of the slits 11a and 11b, the workpiece is ground when the grinding tool rotates in the direction B to grind the workpiece. The coolant can be supplied quickly only to the processed surface of the workpiece whose temperature is rising by the frictional heat immediately after.

Operation of the Grinding Tool When the grinding tool H is used, as shown in the perspective view of FIG. The Coolant supply from a coolant supply source (not shown) is started and the grinding tool H is rotated to start grinding the workpiece. When performing rough grinding, only the outer grindstone portion 40 is slid by sliding the outer tapered cone 20, and when finishing, only the finished grindstone portion 41 is slid by sliding the inner tapered cone 30 or if necessary. Both of these are simultaneously projected by a predetermined amount to perform processing.

  The supplied coolant flows in from the coolant inflow port 13 and circulates in the holder main body 10 through distribution paths X and Y indicated by broken-line arrows in FIG. Here, the symbol X is the outer coolant circulation path, and the symbol Y is the inner coolant circulation path. However, in the right half of the figure, the circulation path X is omitted and only the circulation path Y is illustrated, and the left side of the figure. In the half, the distribution route Y is omitted and only the distribution route X is shown. However, this is for simplification of illustration, and in reality both the distribution routes X and Y are coaxial cylindrical distribution channels. The route is configured.

  The coolant that has flowed in from the coolant inlet 13 is branched into a coolant that is directed to the outer circulation path X and a coolant that is directed to the inner circulation path Y. The coolant toward the outer flow path X first passes through a cylindrical flow path formed by the difference in diameter between the inner peripheral surface 14 of the holder body 10 and the outer tapered cone 24.

Subsequently, the coolant flows to the tip side of the grinding tool H and reaches the tapered portion 22a. However, since the leg portion of the grindstone shoe 40b is in contact with the tapered portion 22a, some of the coolant hinders distribution. It is branched here, flows to the discharge groove 12a formed in the slit 11a, and is discharged to the outside (distribution path X ₁ ).

The remaining coolant passes through the groove portion 23 formed between the tapered portions 22a divided into a plurality of regions shown in FIG. 3 where the legs of the grinding wheel shoe 40b abut, and further flows to the tip side of the grinding tool H. , it is discharged from the discharge groove 12b formed in the slit 11a (distribution channels _{X 2} and _X 3).

  In FIG. 3, the through hole 21 is illustrated in addition to the groove portion 23 between the plurality of tapered portions 22 a, and here, as described above, the grindstone shoe supported by the inner tapered cone 30. Since 41b is penetrated and a distribution | circulation is prevented, a coolant distribute | circulates only on the groove part 23. FIG.

  Of the coolant that has flowed from the coolant inlet 13, the coolant that is branched from the coolant that is directed to the outer flow path X and that is directed to the inner flow path Y first passes through the hole formed in the outer tapered cone 20, and then the outer tapered cone. 20 flows into the interior. Subsequently, it passes through the cylindrical flow path formed by the difference in diameter between the inner peripheral surface 25 of the outer tapered cone 20 and the inner tapered cone outer peripheral surface 33.

Subsequently, the coolant flows to the tip side of the grinding tool H and reaches the tapered portion 31a. However, since the leg portion of the grindstone shoe 41b is in contact with the tapered portion 31a, some of the coolant hinders circulation. It is branched here, flows into the discharge groove 12b formed in the slit 11b, and is discharged to the outside (distribution path Y ₁ ).

The remaining coolant passes through the groove portion 32 formed between the tapered portions 31a divided into a plurality of regions shown in FIG. 6 where the legs of the grinding wheel shoe 41b abut, and further flows to the tip side of the grinding tool H. Then, the liquid is discharged from the discharge groove 12b formed in the slit 11b (distribution paths Y ₂ and Y ₃ ).

  As described above, the coolant discharged to the outside of the holder body 10 has a discharge groove 12a and 12b formed on the front surface in the grinding tool rotation direction B, so that Properly supplied.

  In the present invention, it is preferable that the sum of the cross-sectional areas of the discharge grooves 12 a and 12 b is smaller than the cross-sectional area of the coolant inlet 13. By setting it as such an aspect, the flow velocity in the discharge grooves 12a and 12b of the coolant flowing in from the coolant inlet 13 can be increased.

  In the present invention, it is preferable to provide a difference in cross-sectional area between the discharge groove 12a in the slit 11a in which the rough grindstone portion 40 is accommodated and the discharge groove 12b in the slit 11b in which the finish grindstone portion 41 is accommodated. .

  By adopting such an aspect, when there is a difference between the both in terms of the amount of cooling heat required on the processing surface and the physical properties of the grinding powder discharged from the slit, the effect that the discharge flow rate can be adjusted individually. Play. For example, when the heat generation of the processed surface in the rough grinding is larger than the finishing, the cross-sectional area of the discharge groove 12a in which the rough grindstone portion 40 is accommodated is made larger, and the coolant discharge amount is increased from here. The cooling effect on the rough processed surface can be improved.

  In order to increase (or decrease) the cross-sectional area of the discharge grooves 12a and 12b, it can be achieved by deeply (shallow) engraving the grooves or increasing (decreasing) the number of grooves to be engraved. it can.

In the present invention, by adjusting the cross-sectional area in the step of forming the groove 23, the distribution channel X ₁ on the base end side of the tapered portion 22a, the ratio of the coolant discharge flow rate of the flow path X ₂ and X ₃ of the distal end It can be adjusted freely, and is preferably adjusted to be uniform.

In the present invention, by adjusting the cross-sectional area in the step of forming the groove portion 32, a distribution channel Y ₁ on the base end side of the tapered portion 31a, the ratio of the coolant discharge flow rate of the distribution channel Y ₂ and Y ₃ of the distal end It can be adjusted freely, and is preferably adjusted to be uniform.

  As described above, according to the present invention, since the coolant discharge groove is engraved on the front surface in the tool rotation direction in the slit, the coolant discharge groove is always more than the grindstone when the tool rotates. Since it is also on the upstream side, there is an effect that the coolant can be supplied only to the processed surface of the workpiece that needs to be cooled immediately after being ground by the grindstone. Further, since the slit is provided with a groove, the rigidity of the holder body can be increased as compared with a conventional grinding tool in which a discharge hole is separately provided in the holder body. Also, if the sum of the cross-sectional areas of the discharge grooves is made smaller than the cross-sectional area of the inlet when flowing into the holder body, the coolant flow rate in the discharge grooves will increase, so that the abrasive powder entering the holder body can be discharged. It is possible to improve. Further, when the cross-sectional area of the discharge groove is different between the slit of the roughing grindstone and the slit of the finishing grindstone, the optimum coolant flow rate can be set for each target processing.

  Maintenance frequency can be reduced by improving the cooling effect on the machined surface of the grinding tool, improving the discharge of grinding powder from the grinding tool, and suppressing the reduction in the rigidity of the tool. Useful for grinding.

H ... grinding tool,
10 ... Holder body,
11a, 11b ... slits 12a, 12b ... discharge grooves,
13 ... Coolant inlet 14 ... Holder body inner peripheral surface,
15 ... Cylindrical part,
16 ... proximal end side,
20 ... Outer tapered cone,
21 ... through hole,
22a, 22b ... taper part,
23 ... groove,
24. Outer taper cone outer peripheral surface,
25 ... Outer taper cone inner peripheral surface,
26 ... engaging portion,
30 ... Inner taper cone,
31a, 31b ... taper part,
32 ... groove,
33 ... Inner taper cone outer peripheral surface,
34 ... engaging portion,
40: Coarse whetstone part,
40a: Coarse whetstone,
40b ... Whetstone shoe,
40c: Whetstone shoe engaging portion,
41 ... Finishing wheel part,
41a ... finishing wheel,
41b ... Whetstone shoe,
41c: Whetstone shoe engaging portion,
X, X _{1 to} X ₃ ... coolant flow path (outside),
_Y, Y 1 ~Y 3 _... coolant distribution channels (inside).

Claims (3)

A cylindrical holder body having a plurality of slits in the circumferential direction, a tapered cone contained coaxially with the holder body, a grinding wheel shoe supported by the tapered cone and contained in each of the plurality of slits, and the grinding stone A whetstone attached to the shoe and projecting radially from the holder body,
A grinding tool in which the grindstone shoe is capable of moving back and forth in the radial direction by moving back and forth in the axial direction of the taper cone,
The holder body includes a coolant inlet for supplying coolant into the holder body, and a plurality of discharge grooves formed in the slit for discharging the coolant flowing into the holder body.
The grinding tool, wherein the discharge groove is formed on a front surface of the slit in a tool rotation direction.   The grinding tool according to claim 1, wherein the sum total of the sectional areas of the discharge grooves is smaller than the sectional area of the inlet. It has a plurality of grinding wheels for roughing and a plurality of grinding stones for finishing,
The cross-sectional area of the groove formed in the slit supported by the roughing grindstone is different from the cross-sectional area of the groove formed in the slit supported by the finishing grindstone. Grinding tool as described in.

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