JP2006175574A - Honing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sequentially and properly hone a plurality of bores different in bore diameters by using a single honing head. <P>SOLUTION: This honing method includes a first process to grind a surface of the first bore B to drive a grindstone 4 to grind and deliver while driving to rotate the honing head H having the grindstone 4 free to advance and retreat on a head peripheral surface 1a inside of the first bore B of a work W and a second process to grind a surface of the second bore B by driving the grindstone 4 to grind and deliver while rotating and driving the honing head H inside of the second bore B having an initial diameter different from the first bore B thereafter. A first starting distance between a surface of the first bore and a head end of the grindstone in starting grinding delivering drive in the first process and a second starting distance between a surface of the second bore and the head end of the grindstone in starting the grinding delivering drive in the second process are different from each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a honing method that can be used, for example, for surface finishing of a cylinder bore formed in an engine block.

  For metal workpieces with a rough bore formed using a boring machine or the like, the bore surface may be ground to achieve high-precision inner diameter and good surface roughness. . For example, in a cylinder bore formed in an engine block, the accuracy required for the inner diameter dimension is particularly severe, and honing is generally performed as a grinding finish. The honing machine used in the honing process is equipped with a cylindrical honing head that can feed a grindstone of a desired length from the peripheral surface of the head, and feeds the grindstone while rotating the honing head in the bore. The honing process is performed on the bore surface. Such a honing technique is described in, for example, Patent Document 1 and Patent Document 2 below.

Japanese Patent Laid-Open No. 3-26460 JP-A-9-85623

  The honing process for the surface of the cylinder bore is performed in an engine block production line. Specifically, honing is sequentially performed on the cylinder bores of a plurality of engine blocks flowing through the honing machine attached to the engine block manufacturing line. In the conventional honing technique, the honing head of the honing machine is designed to have an outer diameter slightly smaller than the inner diameter in accordance with the inner diameter of the cylinder bore to be ground. Therefore, when there are cylinder bores having different inner diameters among the plurality of cylinder bores to be ground, according to the conventional technique, it is necessary to prepare a plurality of honing heads whose outer diameters are designed for each inner diameter.

  When honing processing is required for a plurality of cylinder bores with different inner diameters in a single engine block production line, for example, a single honing machine is equipped with a plurality of honing heads with different outer diameters on the production line. In this honing process, it is possible to appropriately switch to a honing head having an outer diameter corresponding to the inner diameter of the bore to be machined and perform a honing process for each cylinder bore. However, in this case, the honing machine needs an ATC mechanism for switching the honing head.

  When honing is required for multiple cylinder bores with different inner diameters in a single engine block production line, or multiple honing machines with different outer diameters of honing heads are permanently installed in a single production line. For each cylinder bore, a technique of performing honing with a processing machine having a corresponding honing head with an outer diameter can be employed. However, in this case, a plurality of honing machines are required in a single engine block production line.

  The present invention has been conceived under such circumstances, and is a method by which a plurality of bores having different inner diameters can be subjected to appropriate honing using a single honing head. The purpose is to provide.

  The honing method provided by the first aspect of the present invention includes a first step and a subsequent second step. In the first step, by rotating and driving a honing head having a head peripheral surface and a grindstone capable of moving back and forth on the head peripheral surface inside the first bore of the workpiece, the grindstone is driven to be fed out by grinding. The surface of the first bore is ground. In the second step, the surface of the second bore is ground by driving the grinding wheel to feed while rotating the honing head inside the second bore having an initial diameter different from that of the first bore. In this method, when starting the grinding feed drive in the first step, the first starting distance between the surface of the first bore and the tip of the grindstone, and when starting the grinding feed drive in the second step, The second starting distance between the surface of the second bore and the tip of the grindstone is different. In the present invention, the rotational drive of the honing head means a drive for rotating a cylindrical honing head having the head peripheral surface as a side surface, ideally around the rotational symmetry axis of the cylinder. In the present invention, the grinding wheel feed-out driving means a grindstone that can be moved back and forth on the head circumferential surface until the bore has a predetermined finished inner diameter (that is, until the grinding finish of the bore surface is completed). This is a drive for adjusting the extension length of the head from the circumferential surface, and consists of a plurality of successive stages in which the feed speed, the feed length, etc. are preset for each stage.

  According to the honing method having such a configuration, a plurality of bores having different inner diameters can be appropriately subjected to honing using a single honing head.

  In the honing process, the grinding wheel of the honing head is polished for each machining (grinding) on the bore surface of the workpiece on which the bore is formed, and the tip surface of the grinding wheel has a shape corresponding to the bore surface that has been ground. Become. Specifically, the end face of the grindstone at the end of each honing process has a curvature corresponding to the curvature of the bore surface that has been ground (the curvature of the circle appearing in the bore cross section). In general, since the amount of change in the bore diameter before and after the honing process is extremely small with respect to the bore diameter, the curvature of the bore surface can be regarded as practically unchanged before and after the honing process. Therefore, when honing is sequentially performed on a plurality of bores having the same inner diameter using a single honing head, the geometrical relative relationship between the bore surface and the grindstone tip surface at the start of each machining is substantially the same. is there. Specifically, the bore surface and the grindstone tip surface at the start of machining are substantially parallel each time, for example, as shown in FIG. 7 (in FIG. 7, a part of the bore cross section and the bore surface are opposed to each other). This represents a partial cross section of the grindstone, and schematically shows the geometrical relationship between the bore surface and the grindstone tip surface (the same applies to FIGS. 8 and 9). In this case, the grinding feed drive under the same conditions is started from the same starting distance (the distance between the bore surface and the grindstone tip surface) at the start of the grinding feed drive over the plurality of honing processes. A homogeneous finish can be achieved.

  However, in multiple honing processes performed using a single honing head, when the target bore type is changed to a bore with a different inner diameter, the bore surface and the grindstone tip surface at the start of both honing processes before and after the change The relative relationships of the shapes are different.

  For example, if the target bore type is changed to the bore X2 having the bore diameter φ2 (<φ1) after honing is performed on a predetermined number of bores X1 having the bore diameter φ1, the machining of the bore X1 immediately before the change is changed. The bore surface and the front end surface of the grindstone H ′ at the start are parallel, for example, as shown in FIG. 8A, whereas the bore surface and the front end of the grindstone H ′ at the start of machining for the bore X2 immediately after the change are made. The planes are not parallel, for example, as shown in FIG. The tip surface of the grindstone H ′ shown in FIG. 8B has a significantly smaller curvature than the surface of the bore X2. When such a grindstone H ′ is driven to be fed out toward the bore surface, first, only the corners of the grindstone H ′ come into contact with the bore surface as shown in FIG.

  Further, for example, when the target bore type is changed to the bore X4 having the bore diameter φ4 (> φ3) after honing is performed on a predetermined number of bores X3 having the bore diameter φ3, the bore X3 immediately before the change is changed. The bore surface and the front end surface of the grindstone H ′ at the start of machining are parallel, for example, as shown in FIG. 9A, whereas the bore surface and the grindstone H ′ at the start of machining on the bore X4 immediately after the change. For example, as shown in FIG. The tip surface of the grindstone H ′ shown in FIG. 9B has a significantly larger curvature than the surface of the bore X4. When such a grindstone H ′ is driven to be fed out toward the bore surface, first, only the center line of the tip surface of the grindstone H ′ comes into contact with the bore surface as shown in FIG.

  In the honing process, the contact mode when the grindstone starts to contact the bore surface greatly affects the final finished state of the bore surface. Therefore, as shown in FIGS. 8 and 9, when the bore type to be machined is changed to a bore having a different inner diameter, the same grinding feed drive is started from the same starting distance in both honing operations before and after the change. As a result, it is often impossible to achieve a uniform surface finish for both the bores before and after the change. For example, when various conditions (feed distance, feed speed, etc.) and start distance included in each stage of grinding feed drive and start distance are set according to the bore type before the change, a good surface finish state for the bore immediately after the change Can often not get.

  On the other hand, according to the first aspect of the present invention, by adopting different starting distances in both honing processes before and after the change of the bore type to be processed into the bores of different inner diameters, it is possible to appropriately cope with the change. can do.

  As described above, the grinding feed drive includes a plurality of stages having different feed speeds and feed lengths. Generally, the first stage feed speed is set to the highest speed, that is, the most rough cutting condition. Further, the grinding feed drive or the first stage thereof is started in a state where the grindstone is located at a position away from the bore surface by a predetermined distance (start distance), and the feed length of the first stage is determined from the drive start position. It is set to a certain length and longer than the starting distance. That is, the grindstone comes into grinding contact with the bore surface for the first time during the first stage. In the first aspect of the present invention, the amount of grinding in the first stage (grinding under the most roughing condition) is performed by appropriately changing the starting distance in the honing process according to the change of the bore type to be processed into the bores having different inner diameters Amount) can be adjusted. By adjusting the first stage grinding amount, it is possible to suppress or absorb the difference in the first grinding contact state of the grindstone with respect to the bore surface and adjust the final finished state of the bore surface. As described above, according to the first aspect of the present invention, a plurality of bores having different inner diameters can be appropriately subjected to honing processing sequentially using a single honing head.

  The honing method provided by the second aspect of the present invention includes a first operation and a subsequent second operation. In the first work, by rotating and driving a honing head having a head peripheral surface and a grindstone that can be moved back and forth on the head peripheral surface inside the first bore of the workpiece, the grindstone is driven to be fed out by grinding. A first step of grinding the surface of the first bore is sequentially performed on the plurality of first bores. In the second operation, the surface of the second bore is ground by driving the grinding wheel to feed while rotating the honing head inside the second bore having an initial diameter different from that of the first bore. The process is sequentially performed on the plurality of second bores. In this method, when starting the grinding feed drive in the first step, the first start distance between the surface of the first bore and the tip of the grindstone, and at least one second step from the beginning in the second operation The second starting distance between the surface of the second bore and the tip of the grindstone when starting the grinding feed drive is different. In addition, the third start distance and the second start distance between the surface of the second bore and the tip of the grindstone when starting the grinding feed driving in the remaining second step in the second operation are different.

  The honing method with such a configuration includes the configuration according to the first aspect described above. Therefore, the effect mentioned above regarding the said 1st side surface is show | played also by the 2nd side surface of this invention.

  In the second aspect of the present invention, preferably, the first start distance and the third start distance are the same. As described above, for the predetermined number of second bores from the beginning in the second work, the delivery drive is started from the second start distance, and the remaining second bores thereafter are different from the second start distance. 3. Feeding drive is started from the starting distance. It may be preferable to set the third start distance to be the same as the first start distance.

  FIG. 1 is a partial cross-sectional view of a honing head H that can be used to perform the honing method according to the present invention, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. The honing head H is provided in a predetermined honing machine (not shown), and includes a head body 1, a spindle 2 (partially omitted), a shoe 3, a grindstone 4, a taper cone 5, and a rod 6 ( (Some are omitted).

  The head body 1 has a peripheral surface 1a, and has a cone storage chamber 1b and a plurality of slits 1c therein. As shown in FIG. 2, the plurality of slits 1 c are opened at the circumferential surface 1 a and the cone storage chamber 1 b and are provided at equal angular intervals in the circumferential direction of the head body 1. A shoe 3 is disposed in each slit 1 c, and a grindstone 4 made of a predetermined material is fixed to an outer end portion of each shoe 3. The tapered cone 5 has a predetermined tapered surface 5 a and is accommodated in the cone accommodating chamber 1 b of the head body 1. As shown in FIG. 1, the inner end of the shoe 3 has a tapered shape parallel to the tapered surface 5 a of the tapered cone 5. The taper cone 5 is urged downward in FIG. 1 by the action of a predetermined elastic member, and each shoe 3 is inward along the radial direction of the head body 1 by the action of the predetermined elastic member. It is energized towards. Therefore, the contact state between the tapered surface 5a of the tapered cone 5 and the inner end portion of the shoe 3 is maintained.

  The spindle 2 is connected to the head main body 1 at one end side thereof, and a rod 6 is disposed therein. The other end of the spindle 2 is connected to a first cylinder (not shown) for driving the honing head H in a vertical direction in FIG. 1 and a motor (not shown) for driving the honing head H to rotate. Are connected. The first cylinder and the motor are connected to the spindle 2 so that the honing head H can be driven independently. One end of the rod 6 in the spindle 2 extends from the spindle 2 to the head body 1 and is fixed to the taper cone 5. The other end (not shown) of the rod 6 is connected to a second cylinder (not shown) disposed in the spindle 2 for translationally driving the tapered cone 5 in the vertical direction of FIG. Yes.

  The honing head H further includes sizing means (not shown) for sizing the inner diameter of the bore to be processed. The sizing means is composed of, for example, an air gauge, and is configured to eject air between the head surface (circumferential surface 1a) and the bore surface, and by measuring the back pressure of the air from the bore surface. The distance to the surface or the bore diameter can be measured. Further, the honing machine is configured so as to be able to appropriately correct the later-described operation of the grindstone 4 based on the value obtained by such a sizing means.

  Such a honing head H translates in the vertical direction in FIG. 1 when the above-described first cylinder is operated, and rotates around the rotation axis Y when the above-described motor is operated. Further, in the honing head H, when the above-described second cylinder is operated and the rod 6 is moved downward in FIG. 1, the taper cone 5 is moved downward, and accordingly, the shoe 3 is removed along the head radial direction. Move towards. As a result, the grindstone 4 is fed out from the peripheral surface 1a for a predetermined length. The feed length from the peripheral surface 1a is ideally the same for all the grindstones 4. Further, the feed length is configured to be adjusted as desired by adjusting the amount of movement of the rod 6 by the second cylinder. The honing machine includes a plurality or a single control unit (not shown) for controlling the driving (translational movement, rotation) of the honing head H and the driving (feeding out) of the grindstone 4.

  The honing method according to the present invention can be carried out, for example, on a cylinder block production line of an automobile engine using a honing machine equipped with the honing head H as described above. In the present embodiment, it is assumed that a plurality of cylinder blocks W, for example, as shown in FIG. In the present embodiment, a bore Ba having an inner diameter of φa or a bore Bb having an inner diameter of φb (<φa) is formed as the bore B in the present embodiment, and the cylinder block W is transferred on the production line and sequentially honed. It is assumed that these two types of bores Ba and Bb are mixed as the bore B of the cylinder block W attached to the cylinder block W. For example, on the production line, after a predetermined number of cylinder blocks W in which all the bores B are bores Ba, a predetermined number of cylinder blocks W in which all the bores B are bores Bb are continuously transferred. Alternatively, the cylinder block W in which all the bores B are bores Ba and the cylinder block W in which all the bores B are bores Bb are alternately transferred. Alternatively, the cylinder block W in which the bore Ba and the bore Bb are alternately formed may be continuously transferred.

  The cylinder block W that has reached the work area of the honing machine equipped with the honing head H is subjected to honing work sequentially in the work area based on the honing method according to the present invention. FIG. 4 shows a flowchart of honing for each bore B.

  In the honing process for each bore B, first, the honing head H is fed into the bore B in step S1. At this time, the grindstone 4 is in a standby state slightly extended from the peripheral surface 1a of the head body 1 or in a retracted standby state. Next, in step S2, the grindstone 4 is sent to a predetermined start position. Specifically, the grindstone 4 is rapidly fed from a position in a standby state to a position for starting grinding feed driving, and is extended from the peripheral surface 1a by a predetermined length. The speed at which the grindstone 4 is fed in this rapid feed is, for example, 1100 φμm / s (φμm represents the amount of spread in the entire diameter direction of the honing head H, and is twice the amount of transition represented by μm in one grindstone 4. Equivalent to). Next, in step S3, grinding feed driving of the grindstone 4 is started. The grinding feed drive is a drive that feeds the grindstone 4 from a predetermined start position to a position where the grinding finish of the bore surface is finished, and includes a plurality of stages. In the present embodiment, the grinding wheel 4 is subjected to a quasi-rapid feed, a first coarse feed, a second coarse feed, a first finish feed, and a second finish feed in order in the grinding feed drive to achieve a grinding finish on the bore surface. . In such grinding feed drive, the feed speed is set lower as the stage progresses. After finishing the grinding feed drive of the grindstone 4 and finishing the grinding finish, the bore B to be processed is changed, and the above-described steps S1 to S3 are repeated.

When the bore surface before processing and the front end surface of the grindstone can be oriented substantially in parallel as shown in FIG. 7 (for example, in this honing process performed sequentially over a plurality of bores B, the same type of bore B as the previous honing process) [When honing is performed on the bore B having the same inner diameter as the previous machining object)] In step S2, the grindstone 4 is rapidly fed to the standard start position P ₀ as shown in FIG. In step S3, the grindstone 4 is ground and driven as shown in FIG. 5 (a) under the standard driving conditions set at the delivery speed and delivery length as shown in FIG. 6 (FIG. 6). The conditions shown are merely examples, and other driving conditions may be adopted). The predetermined control unit included in the honing machine is configured to control the grinding feed driving based on a predetermined program in which the standard driving conditions are set in advance. Further, during grinding with the grindstone 4, the above sizing means functions to constantly measure the bore diameter or grinding amount during processing, and the measured value at the start of each stage is based on the final finished inner diameter. If the value deviates from the value assumed as, the feed length set in the feed stage is adjusted, and the grinding feed drive is corrected.

The standard drive condition and the standard start position P ₀ are the bore surface, the constituent material of the grindstone, and the surface of the finished bore surface in honing when the bore surface before machining and the grindstone tip surface are substantially parallel as shown in FIG. The conditions are ideally optimized and set in advance considering the roughness, the time required for a single honing process, and the like. Under such conditions, the grindstone 4 begins to grind the bore surface during the first semi-rapid feed stage of the grinding feed drive. That is, assuming that the separation distance between the front end surface of the grindstone 4 at the standard start position P ₀ and the surface of the bore B to be ground that has not been ground yet is the standard start distance R ₀ , the grindstone 4 in the semi-rapid feed stage The amount of grinding by corresponds to the difference between the feed length in the semi-rapid feed stage and the standard start distance _R0 .

When the bore surface and the grindstone tip surface before processing are oriented non-parallel as shown in FIG. 10A, for example (in this honing process performed sequentially over the plurality of bores B, a plurality of bores having relatively large diameters). In the case where the honing process is started for the relatively small diameter bore Bb after performing the honing process for Ba), in step S2, the grindstone 4 is moved to the start position P ₁ as shown in FIG. Or it is sent out to the starting position P ₂ as shown in FIG. In step S3, the grindstone 4 is first driven under the semi-rapid feed conditions of the first stage of the grinding feed drive.

And the distal end surface of the grinding 4 when it is in the start position P _1, yet when the distance between the surface of the bore B of the grinding subject which does not receive the grinding start distance R ₁ to, start distance R ₁ is the standard start distance R Shorter than ₀ . Therefore, when the grinding feed drive is started from the start position P ₁ , as shown in FIG. 5B, compared with the case where the grinding feed drive is started from the standard start position P ₀ , the quasi-rapid feed stage is started. The amount of grinding is large. Therefore, at the end of the semi-rapid feed stage or at the start of the first coarse feed stage, the feed length in the first coarse feed stage following the semi-rapid feed stage is based on the measured values related to the bore diameter or grinding amount obtained by the sizing means described above. Is corrected. Specifically, in the final grinding feed drive, the first coarse feed stage is completed so that the first coarse feed stage is completed at the end position of the first coarse feed stage that is assumed based on the final finished inner diameter. The feed length is shortened. After the first rough feed stage in which the feed length is corrected in this way, the subsequent stages are sequentially performed, and the bore B is ground.

On the other hand, the front end surface of the grinding wheel 4 when it is in the start position P _2, yet when the distance between the surface of the grinding target bore B not subjected to grinding start distance R ₂ to, start distance R ₂ is the standard start Longer than distance _R0 . Therefore, when the grinding feed driving is started from the start position P ₂ , the grinding amount at the quasi-rapid feed stage, as shown in FIG. 5C, than when the grinding feed driving is started from the standard start position P ₀ . There are few. Therefore, the feed length in the first rough feed stage after the semi-rapid feed stage is based on the measured values related to the bore diameter or grinding amount obtained by the sizing means at the end of the semi-rapid feed stage or at the start of the first coarse feed stage. It is corrected. Specifically, in the final grinding feed drive, the first coarse feed stage is completed so that the first coarse feed stage is completed at the end position of the first coarse feed stage that is assumed based on the final finished inner diameter. The feed length is extended. After the first rough feed stage in which the feed length is corrected in this way, the subsequent stages are sequentially performed to finish the bore B.

As described above, when the bore surface and the grindstone tip surface before processing are not parallel as shown in FIG. 10 (a), the position of the grindstone tip surface when the grinding feed driving starts is a standard start. A start position P ₁ or a start position P ₂ different from the position P ₀ is employed. The degree of correction from the standard start position P ₀ to the start positions P ₁ and P ₂ , and which of the start position P ₁ corrected forward and the start position P ₂ corrected backward is used. Ideally considering the geometrical relationship between the previous bore surface and the tip of the grinding wheel, the material of the bore surface and grinding wheel, the surface roughness of the finished bore surface, the time required for a single honing operation, etc. And preset.

When the bore surface before processing and the front end surface of the grindstone are oriented non-parallel as shown in, for example, FIG. 10B (in this honing process performed sequentially over the plurality of bores B, a plurality of bores Bb having relatively small diameters) In the case where the honing process is started for the bore Ba having a relatively large diameter after the honing process is performed), in step S2, the grindstone 4 is moved to the start position P ₃ as shown in FIG. Or it is sent out by rapid feed to the start position P ₄ as shown in FIG. In step S3, the grindstone 4 is subjected to grinding feed driving with correction for adjusting the feed length in the first coarse feed stage. Specifically, it is the same as described above with respect to the case where the bore surface and the grindstone tip surface before processing are oriented non-parallel as shown in FIG. The degree of correction from the standard start position P ₀ to the start positions P ₃ and P ₄ and which of the start position P ₃ corrected forward and the start position P ₄ corrected backward is used. Ideally considering the geometrical relationship between the previous bore surface and the tip of the grinding wheel, the material of the bore surface and grinding wheel, the surface roughness of the finished bore surface, the time required for a single honing operation, etc. And preset.

In the present invention, starting the grinding feed drive of the grindstone 4 from the start positions P ₁ and P ₃ and relatively increasing the grinding amount in the semi-rapid feed stage is the time required for a single honing process (cycle time). ) Tends to be preferable. In addition, starting the grinding feed drive of the grindstone ₄ from the start positions P ₂ and P ₄ and relatively reducing the grinding amount in the semi-rapid feed stage relatively reduces the surface roughness (for example, the value of Rz). There is a tendency to be preferable in reducing the size.

  As described above, according to the present invention, it is possible to appropriately cope with a change in the inner diameter of the bore B to be processed by changing the starting position or the starting distance at the start of grinding feed driving of the grindstone 4. . For example, the surface texture of the finished surface of the bore B can be adjusted only by changing the start distance without changing the feed speed in the first stage (quasi-rapid feed) of the grinding feed drive according to the change in the bore diameter. Become. Therefore, according to the present invention, a plurality of bores having different inner diameters can be honed appropriately and sequentially using a single honing head.

  Regarding the grinding feed drive in the present invention, a spark-out stage may be added after the second finish feed stage. In the spark-out stage, the grindstone 4 is retracted by a predetermined length at a predetermined speed. In the honing process that involves pressing the bore surface with a grindstone for a predetermined period, the workpiece on which the bore is formed may be compressed due to the pressing force. In this case, when the pressing force is released, the bore surface that has been receiving the pressing force tends to shrink and the bore diameter tends to decrease. In the spark-out stage, the grindstone 4 is gradually retracted to grind the bore surface while gradually releasing the compressed state of the bore surface.

In the honing process performed sequentially over a plurality of bores B, even if the honing process is performed on the same type of bore B [bore having the same inner diameter as the previous process target] as the previous honing process, The front bore surface and the grindstone tip may not be oriented in parallel. This is because in the honing process for a few times (for example, once), the tip surface of the grindstone 4 may not be polished and deformed to a shape that matches the finished surface of the bore B. In the present invention, in such a case, even in the case where honing is performed on the same type of bore B as the previous honing in the honing processing performed sequentially over the plurality of bores B, A driving mode is adopted in which the grinding feed driving is started from the start positions P _{1 to} P ₄ . Then, after the bore surface and the grindstone tip surface before processing are in a state where they can be oriented in parallel or substantially in parallel as shown in FIG. 7, a driving mode is adopted in which grinding feed driving is started from the standard start position P ₀ . For example, the driving mode in which the grinding feed driving is started from the start position P _{1 is} adopted in several honing processes, and thereafter, the start position is sequentially approached from P ₁ to P ₀ every several honing processes. A drive mode is adopted in which the grinding feed drive is started from the standard start position P ₀ after the bore surface and the grindstone tip surface before processing become in a state where they can be oriented in parallel or substantially in parallel as shown in FIG.

  In addition, the present invention can be applied not only to honing for two types of bores B (bore Ba, Bb), but also for honing three or more types of bores sequentially.

It is a fragmentary sectional view of the honing head which can be used to implement the honing method according to the present invention. It is sectional drawing along line II-II of FIG. An example of a cylinder block having a bore to be machined is shown. The flowchart of the honing process for every bore is represented. A mode of grinding feed driving is schematically shown. An example of conditions for each delivery stage set in the standard drive program is shown. The figure shows the relative relationship in shape between the bore surface at the start of each machining and the tip of the grindstone when honing is sequentially performed on a plurality of bores having the same inner diameter using a single honing head. In the case where the type of bore to be machined is changed to a bore with a small inner diameter, it represents the geometric relative relationship between the bore surface and the grindstone tip surface at the start of both machining before and after the change. In the case where the type of bore to be machined is changed to a bore having a large inner diameter, it represents the geometrical relative relationship between the bore surface and the grindstone tip surface at the start of both machining before and after the change. An example in which the bore surface before processing and the tip of the grindstone are non-parallel is shown.

Explanation of symbols

H Honing head 1 Head body 1a Peripheral surface 1c Slit 2 Spindle 3 Shoe 4 Grinding wheel 5 Taper cone 6 Rod B, Ba, Bb Bore

Claims (3)

A honing head having a head peripheral surface and a grindstone that can be moved back and forth on the head peripheral surface is rotated and driven inside the first bore, and the grindstone is driven to be fed out by grinding to drive the surface of the first bore. A first step of grinding,
After the first step, the surface of the second bore is driven by grinding and feeding the grindstone while rotating the honing head inside the second bore having an initial diameter different from that of the first bore. A second step of grinding,
When starting the grinding feed drive in the first step, and when starting the grinding feed drive in the second step, and a first starting distance between the surface of the first bore and the tip of the grindstone. The honing method, wherein the second starting distance between the surface of the second bore and the tip of the grindstone is different. A honing head having a head peripheral surface and a grindstone that can be moved back and forth on the head peripheral surface is rotated and driven inside the first bore, and the grindstone is driven to be fed out by grinding to drive the surface of the first bore. A first step of grinding the first step for a plurality of first bores;
A second step of grinding the surface of the second bore by driving the grinding wheel to feed while rotating the honing head inside a second bore having an initial diameter different from that of the first bore. A second operation that is sequentially performed for a plurality of second bores after the first operation,
At least one second step from the beginning in the first operation and the first starting distance between the surface of the first bore and the tip of the grindstone when starting the grinding feed driving in the first step. The second starting distance between the surface of the second bore and the tip of the grindstone when starting the grinding feed drive in is different,
The third start distance between the surface of the second bore and the tip of the grindstone when starting the grinding feed drive in the remaining second step in the second operation, and the second start distance are: Different honing method.   The honing method according to claim 2, wherein the first start distance and the third start distance are the same.

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