JP2012091284A - Grinding method and multifunction grinding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding method and a multifunction grinding machine capable of reducing a cost for a finish grinding wheel by reducing a grinding volume by the finish grinding wheel as much as possible.SOLUTION: The multifunction grinding machine 1 executes a rough grinding step grinding the workpiece W supported by a supporting device 20 by the rough grinding wheel 73 so as to be leave a preset finish grinding margin, and a finish grinding step grinding the finish grinding margin of the workpiece W continuously supported by the supporting device 20 by the finish grinding wheel after the rough grinding step. The finish grinding margin is set on the basis of at least one of the thermal displacement of the multifunction grinding machine 1 and a changing amount of a grinding force caused by the rough grinding wheel. A shape with he finish grinding margin left in the workpiece W does not depend on a shape of the rough grinding wheel 73.

Description

  The present invention relates to a grinding method including a roughing process and a finishing process, and a composite grinding machine to which the grinding method is applied.

  Conventionally, in U.S. Pat. No. 5,392,566 (Patent Document 1), in a composite grinding machine equipped with a large-diameter roughing grinding wheel and a small-diameter finishing grinding wheel, a cam shape having a concave curved surface Is described.

US Pat. No. 5,392,566

  Generally, the volume that can be ground per unit time by the grinding wheel for finishing is smaller than the volume that can be ground per unit time by the grinding wheel for roughing. Therefore, it is desirable to grind as much volume as possible with a roughing grinding wheel and to reduce the grinding volume with a finishing grinding wheel as much as possible for one workpiece. Until now, however, the grinding volume of each of the roughing grinding wheel and the finishing grinding wheel has been determined by the restrictions due to the machine configuration and the production line cycle time. Therefore, the grinding volume by the finishing grinding wheel has to be increased, and the finishing grinding wheel has reached the end of its life earlier than the roughing grinding wheel. As a result, it has been usual that the cost of the grinding wheel for finishing is increased.

  The present invention has been made in view of such circumstances, and a grinding method capable of reducing the cost required for a finishing grinding wheel by reducing the grinding volume by the finishing grinding wheel as much as possible. And it aims at providing a compound grinder.

  (Claim 1) A grinding method according to the present invention comprises a supporting device for supporting a workpiece, a roughing grinding wheel that can be selectively used with respect to the supporting device, and can be used selectively. A grinding method using a composite grinding machine, comprising: a composite grinding wheel table equipped with a grinding wheel; and a control device that selectively grinds the workpiece using the roughing grinding wheel and the finishing grinding wheel In the state where the workpiece is supported by the support device, a roughing step of roughing the workpiece using the roughing grinding wheel so as to leave a set finishing allowance; After the roughing step, in a state where the workpiece is continuously supported by the support device, a finishing process step of performing a finishing process so as to remove the finishing allowance using the finishing grinding wheel. Execute the finishing allowance, the composite The rough grinding wheel is set based on at least one of the amount of thermal displacement of the machine and the amount of change in grinding resistance caused by the roughing grinding wheel, and the shape with the finishing allowance remaining in the workpiece The shape does not depend on the shape.

  (Claim 2) Further, in the present invention, a plurality of the composite grinders are arranged between one pre-process and one post-process in the production line, and each of the composite grinders is the one in the production line. The roughing step and the finishing step are sequentially performed on the workpiece conveyed from the previous step, and after the finishing step, the workpiece is discharged to the subsequent step of the production line, The composite grinding machine may be executed in parallel between the pre-process and the post-process.

  (Claim 3) In the present invention, the ground portion of the workpiece is formed in a cam shape, and the finishing allowance is a cam caused by a bending deformation amount of the workpiece or the composite grinder due to grinding resistance. It may be set based on the profile grinding error.

  (Claim 4) In the present invention, the grinding portion of the workpiece is formed in a cam shape having a concave curved surface having a curvature radius R1 on an outer peripheral surface, and the radius R2 of the roughing grinding wheel and the finishing process are performed. The grinding wheel radius R3 may be formed smaller than the radius of curvature R1 of the concave curved surface.

  (Claim 5) Further, a composite grinding machine of the present invention includes a supporting device for supporting a workpiece, a roughing grinding wheel that is arranged to be relatively movable with respect to the supporting device, and can be used selectively. In a composite grinding machine comprising a composite grinding wheel table equipped with a finishing grinding wheel, and a control device for selectively grinding the workpiece using the roughing grinding wheel and the finishing grinding wheel, The control device is set based on at least one of a thermal displacement amount of the composite grinding machine and a grinding resistance change amount caused by the roughing grinding wheel in a state where the workpiece is supported by the support device. The roughing grinding wheel is used to rough the workpiece, and the finishing grinding wheel is removed after the roughing using the finishing grinding wheel. Processing.

  (Claim 1) According to the present invention, by applying a composite grinding machine including a roughing grinding wheel and a finishing grinding wheel, it is possible to integrate the roughing process and the finishing process. Accordingly, since the workpiece is not detached from the support device between the rough machining step and the finishing machining step, the workpiece mounting phase error due to the removal is not included, so that the finishing allowance can be reduced.

  Further, according to the present invention, the finishing allowance is set based on at least one of the thermal displacement amount of the composite grinding machine and the change amount of the grinding resistance caused by the roughing grinding wheel, leaving the finishing allowance in the workpiece. The shape is not dependent on the shape of the roughing grinding wheel. Thus, the finishing allowance is set regardless of the shape of the roughing grinding wheel, and is set based on at least one of the amount of thermal displacement and the amount of change in grinding resistance caused by the roughing grinding wheel. . As a result, the finishing allowance can be reduced.

  Therefore, according to the present invention, in addition to reducing the finishing allowance by not detaching the workpiece by integrating processes, the finishing allowance is reduced by setting the finishing allowance as described above. As a result, the finishing allowance can be minimized. As a result, the life of the grinding wheel for finishing can be extended, and the cost required for the grinding wheel for finishing can be reduced.

  (Claim 2) Conventionally, in a production line, when a roughing process and a finishing process are performed on a workpiece conveyed from a previous process and discharged to a subsequent process, only a roughing grinding wheel is used. A grinding machine dedicated to the roughing process provided and a grinding machine dedicated to the finishing process provided with only a grinding wheel for finishing have been installed. Since the cycle time is determined for the production line, both the grinding time by the grinding machine dedicated to the roughing process and the grinding time by the grinding machine dedicated to the finishing process should be within the cycle time of the production line. Each processing condition is set. According to these processing conditions, there is usually a tendency for finishing by a grinding machine dedicated to the finishing process to be excessive. Therefore, the life of the grinding wheel for finishing is shortened.

  However, as in the present invention, by executing a plurality of composite grinders in parallel between the pre-process and the post-process, each composite grinder can execute a roughing process and a finishing process. it can. And in each compound grinder, since the finishing allowance can be minimized as described above, the life of the grinding wheel for finishing can be extended. Therefore, the cost required for the grinding wheel for finishing can be reduced.

  In addition, by running multiple complex grinders in parallel, the time obtained by dividing the grinding time by each complex grinder by the number of complex grinders is the roughing process and finishing process for one workpiece. It takes time to complete. Here, the grinding time by each composite grinding machine can be shortened because the workpiece is not detached from the roughing process to the finishing process. Furthermore, since the finishing allowance can be minimized, the total time of the roughing process and the finishing process can be shortened. Therefore, compared to the conventional method, the time obtained by dividing the grinding time by each compound grinder by the number of compound grinders is much larger than the conventional grinder time for the roughing process or finishing process. Can be shortened. Therefore, the cycle time of the production line can be shortened.

  (Claim 3) When the cam shape is ground, the cam profile as the machining position is represented by the rotational phase and the lift amount. Here, each component of the workpiece or the composite grinding machine is bent and deformed by the grinding resistance. And a cam profile is often set as a thing without the said bending deformation. By the way, when the grinding part of a workpiece is a cylindrical outer peripheral surface, the outer diameter after grinding becomes larger than the target grinding diameter due to the bending deformation. For this reason, spark-out or the like is performed in cylindrical grinding. However, when grinding the cam shape, it is necessary to change the position of the grinding wheel according to the rotational phase of the workpiece. For this reason, when the cam shape is ground, the bending deformation causes an error in the shape after the actual grinding with respect to the cam profile (this is referred to as a cam profile grinding error). This cam profile grinding error may occur in the cutting direction (direction of excessive cutting) rather than the cam profile. Therefore, in the present invention, the finishing allowance is determined based on the cam profile grinding error. Thereby, since the cam profile grinding error can be surely eliminated in the finishing process, the workpiece after the finishing process is not affected.

  (Claim 4) By making the radius R2 of the roughing grinding wheel smaller than the radius of curvature R1 of the cam-shaped concave curved surface, the roughing grinding wheel can grind to the final finished shape. . That is, the finishing allowance can be made zero by the roughing grinding wheel. However, in practice, grinding is not performed until the finishing allowance becomes zero by the roughing grinding wheel. And the shape which left the finishing allowance in a workpiece can be made into the shape which does not depend on the shape of the grinding wheel for roughing. That is, the finishing allowance can be made the same amount in the concave curved surface portion and the portion other than the concave curved surface. Therefore, even when a cam shape having a concave curved surface is ground, the finishing allowance can be set to a minimum without depending on the shape of the roughing grinding wheel. Further, by making the radius R3 of the finishing grinding wheel smaller than the curvature radius R1 of the cam-shaped concave curved surface, the finishing grinding wheel can surely perform grinding until reaching the final finishing shape.

  Moreover, as above-mentioned, finishing allowance can be made into the same quantity by the part of a concave curved surface, and parts other than a concave curved surface. As a result, in the finishing process, the grinding resistance by the finishing grinding wheel can be prevented from changing depending on the rotational phase of the workpiece. Thereby, the life of the grinding wheel for finishing can be prolonged, and the time of the finishing process can be shortened.

  (Claim 5) The present invention regards the invention relating to the above-described grinding method as a composite grinding machine. Thereby, there exists an effect similar to the effect by the grinding method mentioned above. Further, the other characteristics of the grinding method described above can also be applied to the invention related to the composite grinding machine. In this case, the same effect as the corresponding grinding method can be obtained.

Embodiment: Plan view of a composite grinder. Embodiment: It is the figure which looked at the grinding | polishing site | part of the to-be-processed object from the axial direction, and shows the comparison figure with the grinding wheel for roughing and the grinding wheel for finishing. Embodiment: It is the figure which looked at the grinding | polishing site | part of the workpiece from the axial direction, and is a figure which shows a cam profile and a cam profile grinding error. Embodiment: It is a block diagram of a production line. Reference Example 1: A configuration diagram of a production line. (A) About this embodiment, it is a graph which shows the machining allowance and grinding process time in each process, (b) About the reference example 1, it is a graph which shows the machining allowance and grinding process time in each process, (c) Reference example 2 It is a graph which shows the machining allowance and grinding process time in each process. It is a table | surface which shows tool cost about embodiment and the reference examples 1 and 2. FIG.

<Embodiment>
(Composition of compound grinding machine)
The grinding method and composite grinding machine of this embodiment will be described with reference to FIGS. As shown in FIG. 1, the composite grinding machine 1 will be described by taking a whetstone traverse type as an example. The composite grinding machine 1 includes a bed 10, a support device 20, a grindstone support device 60, and a control device 80.

  The bed 10 is formed in a substantially rectangular shape, for example, and is fixed on the floor. On the upper surface of the bed 10, two grinding wheel table guide rails 11 on which the grinding wheel support device 60 can slide are formed so as to extend in the left-right direction (Z-axis direction) in FIG. 1 and in parallel with each other. Has been. The bed 10 is provided with a grinding wheel support Z-axis ball screw 12 for driving the grinding wheel support device 60 in the left-right direction in FIG. 1 between the two grinding wheel support rails 11. A grinding wheel base Z-axis motor 13 for rotating the base Z-axis ball screw 12 is disposed.

  The support device 20 rotatably supports the workpiece W. In the present embodiment, the workpiece W is a camshaft, and the ground portion of the workpiece W is a cam-shaped cam outer peripheral surface. Therefore, the support device 20 supports both ends of the camshaft so as to be rotatable around the axis of the camshaft that is the workpiece W. The support device 20 includes a headstock 21 that supports one end of the camshaft and a tailstock 22 that supports the other end of the camshaft. The support device 20 is provided at a position on the upper surface of the bed 10 facing the front side of the guide rail 11 for the grindstone table, and is provided such that the axial direction of the camshaft is the Z-axis direction.

  The grinding wheel support device 60 includes a grinding wheel base traverse base 61 and a composite grinding wheel base 62. The grinding wheel base traverse base 61 is formed in a rectangular flat plate shape, and is disposed on the upper surface of the bed 10 so as to be slidable on the grinding wheel base guide rail 11 in the Z-axis direction. The wheel head traverse base 61 is connected to a nut member of the wheel head Z-axis ball screw 12 and is traversed along the wheel head guide rail 11 by driving the wheel head Z-axis motor 13. Two X-axis guide rails (not shown) on which the composite grinding wheel table 62 can slide are extended on the upper surface of the grinding wheel table traverse base 61 so as to extend in the vertical direction (X-axis direction) in FIG. Are formed parallel to each other. Furthermore, an X-axis ball screw (not shown) for driving the composite grinding wheel base 62 in the vertical direction of FIG. 1 is disposed between the X-axis guide rails on the grinding wheel base traverse base 61. An X-axis motor (not shown) that rotationally drives the ball screw is disposed.

  The composite grinding wheel head 62 includes a grinding wheel head main body 71, a grinding wheel head turning mechanism 72, a roughing grinding wheel 73, a finishing grinding wheel 74, and grinding wheel rotation motors 75 and 76. The wheel head main body 71 is slidably disposed on the X-axis guide rail in the upper surface of the wheel head traverse base 61. The grindstone head main body 71 is connected to a nut member of the X-axis ball screw, and moves along the X-axis guide rail by driving the X-axis motor. That is, the grindstone head body 71 can move relative to the camshaft supported by the support device 20 in the X-axis direction and the Z-axis direction.

  The grinding wheel head main body 71 is supported by the grinding wheel head turning mechanism 72 so as to be turnable about the Y axis (around the normal axis in FIG. 1) with respect to the grinding wheel head traverse base 61. The turning axis C of the grinding wheel head turning mechanism 72 is located near the center of the grinding wheel head traverse base 61. Further, a roughing grinding wheel 73 and a finishing grinding wheel 74 are provided on the outer peripheral side of the grinding wheel base body 71 around the turning axis C so as to be rotatable around a horizontal axis. The roughing grinding wheel 73 is formed in a disk shape having a radius R2, and is a grinding wheel suitable for roughing. The finishing grinding wheel 74 is formed in a disk shape having a radius R3 (here, the same as R2), and is a grinding wheel suitable for finishing. The finishing grinding wheel 74 is provided at a position that is symmetrical about the turning axis C with respect to the position of the roughing grinding wheel 73. That is, the roughing grinding wheel 73 and the finishing grinding wheel 74 can be selectively used. Further, the grindstone main body 71 is provided with grindstone rotating motors 75 and 76 that can rotate the roughing grindstone 73 and the finishing grindstone 74, respectively.

  The control device 80 performs NC control of the rotation of the main shaft, the X-axis position and the Z-axis position of the composite grindstone table 62, and the turning angle of the composite grindstone table 62. Further, the control device 80 rotates the grinding wheel rotating motors 75 and 76 that rotationally drive the grinding wheel 73 for roughing and the grinding wheel 74 for finishing. That is, after positioning the composite grindstone head 62 by the grindstone head turning mechanism 72 by the control device 80, the composite grindstone for the camshaft as the workpiece W is rotated while rotating any of the grindstones 73 and 74 to be ground. By controlling the X-axis position and the Z-axis position of the table 62, the cam outer peripheral surface of the camshaft that is the workpiece W is ground.

  As described above, the composite grinding machine 1 enables process integration between the roughing process by the roughing grinding wheel 73 and the finishing process by the finishing grinding wheel 74. Thereby, since the camshaft which is the workpiece W is not detached from the support device 20 between the roughing process and the finishing process, an attachment phase error of the camshaft which is the workpiece W due to the removal is included. There is no. Accordingly, the finishing allowance by the finishing grinding wheel 74 can be reduced as much as it is not necessary to consider the mounting phase error.

(Camshaft cam outer surface and grinding wheel shape)
Next, the cam outer peripheral surface of the camshaft as the workpiece W, the roughing grinding wheel 73, and the finishing grinding wheel 74 will be described with reference to FIG. The cam outer peripheral surface of the camshaft has two concave curved surfaces W1, W2 as shown by the solid line in FIG. Specifically, the cam outer peripheral surface of the camshaft has concave curved surfaces W1, W2 in the vicinity of the middle between both ends of the reference circle and the position where the lift amount is maximum. The minimum value of the radius of curvature of these concave curved surfaces W1, W2 is R1.

  Further, a shape Wa in a state where the grinding process by the roughing grinding wheel 73 is finished on the cam outer peripheral surface of the camshaft is shown by a one-dot chain line in FIG. The shape Wa indicated by the one-dot chain line is a cam profile that is ground by the grinding wheel 73 for roughing. That is, the difference between the shape Wa indicated by the one-dot chain line and the final shape W indicated by the solid line is a finishing allowance for the finishing grinding wheel 74.

  As shown in FIG. 2, the radius R2 of the roughing grinding wheel 73 and the radius R3 of the finishing grinding wheel 74 are formed to be smaller than the minimum value R1 of the curvature radius of the concave curved surfaces W1, W2. Therefore, the roughing grinding wheel 73 can be ground to the final finished shape W of the outer peripheral surface of the cam indicated by the solid line in FIG. In other words, the roughing grinding wheel 73 ultimately makes it possible to reduce the finishing allowance by the finishing grinding wheel 74 to zero. However, in practice, grinding is not performed until the finishing allowance becomes zero by the roughing grinding wheel 73.

  In other words, as shown by the alternate long and short dash line in FIG. 2, the shape Wa that leaves the finishing allowance on the outer peripheral surface of the cam can be a shape that does not depend on the shape of the roughing grinding wheel 73. That is, the finishing allowance can be set to the same amount for the concave curved surfaces W1, W2 and the portions other than the concave curved surfaces W1, W2. Therefore, even when the cam shape having the concave curved surfaces W1, W2 is ground, the finishing allowance can be set to the minimum without depending on the shape of the roughing grinding wheel 73.

  As described above, the radius R2 of the roughing grinding wheel 73 and the radius R3 of the finishing grinding wheel 74 are the same here. Further, by making the radius R3 of the finishing grinding wheel 74 smaller than the radius of curvature R1 of the cam-shaped concave curved surface, the finishing grinding wheel 74 can surely perform grinding until reaching the final finishing shape.

(Setting method of finishing allowance)
Next, a method for setting a finishing allowance for performing grinding with the finishing grinding wheel 74 will be described. The finishing allowance is a part that is ground by the finishing grinding wheel 74 in the finishing process, and a part that is left uncut by the roughing grinding wheel 73 in the roughing process.

  The shape that leaves the finishing allowance is a shape that does not depend on the shape of the roughing grinding wheel 73 as described above. Accordingly, the finishing allowance is set regardless of the shape of the roughing grinding wheel 73. Furthermore, as described above, by not detaching the camshaft that is the workpiece W from the support device 20, it is not necessary to consider the finishing allowance due to the mounting phase error accompanying the detachment of the workpiece W. Therefore, the finishing allowance is set regardless of the attachment phase error accompanying the detachment of the workpiece W. The finishing allowance includes (1) the amount of thermal displacement of the composite grinding machine 1, (2) the amount of change in grinding resistance caused by the roughing grinding wheel 73, and (3) the cam outer periphery of the camshaft that is the workpiece W. It is set based on the cam profile grinding error of the surface.

  When thermal displacement occurs in the composite grinding machine 1, the relative distance between the roughing grinding wheel 73 and the grinding portion of the camshaft that is the workpiece W changes. Accordingly, the amount of cutting by the roughing grinding wheel 73 varies depending on the amount of thermal displacement of the composite grinding machine 1. Therefore, the finishing allowance is set in consideration of the thermal displacement amount of the composite grinding machine 1.

  The amount of change in grinding resistance caused by the roughing grinding wheel 73 is also called the sharpness of the so-called roughing grinding wheel 73. The sharpness of the grinding wheel changes immediately after dressing of the grinding wheel and after a large amount of grinding is performed after dressing. Even in a state where the grinding conditions are not changed at all, the amount of cutting changes as the sharpness of the grinding wheel changes. And the change in the sharpness of the grinding wheel appears as a change in grinding resistance in a state where the grinding conditions are not changed at all. Accordingly, the finishing allowance is set in consideration of the amount of change in grinding resistance caused by the roughing grinding wheel 73.

  The cam profile grinding error will be described with reference to FIG. In FIG. 3, the final shape W in a state where the grinding by the finishing grinding wheel 74 is finished is indicated by a solid line, and the shape Wa1 in a state where the grinding by the roughing grinding wheel 73 is finished is indicated by a one-dot chain line. The shape Wa <b> 1 indicated by the alternate long and short dash line is a cam profile that is ground by the roughing grinding wheel 73. The cam profile is represented by the rotational phase and lift amount of the camshaft that is the workpiece W. This cam profile is a command value from the control device 80. When each component of the composite grinding machine 1 is actually driven on the basis of the command value to grind the cam outer surface of the camshaft, which is the workpiece W, there is an error with respect to the ideal cam profile. Produce. This error is referred to as a cam profile grinding error.

  Here, the workpiece W or each component of the composite grinding machine 1 is bent and deformed by the grinding resistance. And the cam profile is set as a thing without the said bending deformation. By the way, when the grinding site | part of the to-be-processed object W is a cylindrical outer peripheral surface, the outer diameter after grinding will become a diameter larger than a target grinding diameter by the said bending deformation. For this reason, spark-out or the like is performed in cylindrical grinding.

  However, when grinding the cam outer peripheral surface of the camshaft, it is necessary to change the position of the roughing grinding wheel 73 in the X direction according to the rotational phase of the camshaft. Therefore, when grinding the outer peripheral surface of the cam, the bending deformation causes the shape Wa2 after actual grinding to cause a cam profile grinding error with respect to the cam profile Wa1. This cam profile grinding error may occur in the cutting direction (direction of excessive cutting) than the cam profile Wa1. Therefore, the finishing allowance is set in consideration of the cam profile grinding error. In FIG. 3, the shape Wa2 after actual grinding is shown only in part, and the part not shown in the figure means that it is the same as the cam profile Wa1.

  As explained above, in addition to reducing the finishing allowance by not detaching the camshaft that is the workpiece W due to process integration, the finishing allowance can be set regardless of the shape of the roughing grinding wheel 73, The finishing allowance can be minimized by combining the reduction of the finishing allowance by setting the finishing allowance as described above. As a result, the life of the grinding wheel for finishing can be extended, and the cost required for the grinding wheel for finishing can be reduced.

(Grinding system in production line)
Next, the grinding system in the production line in this embodiment will be described with reference to FIG. The production line is a line for producing a camshaft that is the workpiece W. Only the part where the composite grinding machine 1 is arranged in the production line will be described. This part is called a grinding system.

  The production line of the camshaft that is the workpiece W is a composite grinding that performs the above-described grinding process (roughing process and finishing process) of the cam outer peripheral surface between one pre-process 110 and one post-process 120. Two boards 1 are arranged. That is, the grinding system in the present embodiment is configured by two composite grinding machines 1. Here, the reason why the pre-process 110 and the post-process 120 are set to one is that the camshafts, which are the workpieces W, one by one from the pre-process 110 are transferred to the grinding process, and one post-process is performed from the grinding process. This is to specify the case of discharging to step 120.

  The plurality of composite grinding machines 1, 1 are executed in parallel between the pre-process 110 and the post-process 120. Each composite grinding machine 1 performs the same grinding process. Specifically, each composite grinding machine 1 sequentially performs a roughing process and a finishing process on the camshaft that is the workpiece W conveyed from the previous process 110 of the production line, and after the finishing process The camshaft that is the workpiece W is discharged to the post-process 120 of the production line.

  That is, when one first workpiece W is conveyed from the previous process 110, one composite grinding machine 1 performs a roughing process and a finishing process and discharges it to the subsequent process 120. When the next workpiece W is conveyed from the pre-process 110, the other composite grinding machine 1 performs the roughing process and the finishing process and discharges it to the post-process 120. Thereafter, processing is performed alternately. By doing in this way, the cost required for the finishing grinding wheel 74 can be reduced, and the cycle time of the production line can be shortened. Details of this point will be described later.

<Reference Example 1>
The grinding method and grinding machine of Reference Example 1 will be described with reference to FIG. The grinding machine in Reference Example 1 is such that the composite grinding wheel base 62 is a grinding wheel base having a single grinding wheel with respect to the composite grinding machine 1 in the present embodiment. That is, the grinding machine of this embodiment has one grinding wheel.

  And, as shown in FIG. 5, the grinding system in the production line in Reference Example 1 includes a first grinding machine 130 having a roughing grinding wheel 73 between the pre-process 110 and the post-process 120, for finishing. A second grinding machine 140 provided with a grinding wheel 74 is arranged in order. The first grinding machine 130 performs only the roughing process by the roughing grinding wheel 73. On the other hand, the second grinding machine 140 performs only the finishing process using the finishing grinding wheel 74. As described in the present embodiment, the radius of the roughing grinding wheel 73 is R2, the radius of the finishing grinding wheel 74 is R3 (= R2), and the camshaft is the workpiece W. Are formed smaller than the minimum value R1 of the radius of curvature of the concave curved surfaces W1, W2 on the outer peripheral surface of the cam. In this case, the cycle time of the production line becomes longer than in the present embodiment. However, the cycle time of the production line can be shortened as compared with the case where the radius of the grinding wheel for roughing is larger than the minimum value R1 of the curvature radius of the concave curved surfaces W1, W2.

<Reference Example 2>
In order to consider the tool cost and the production line cycle time in the present embodiment, as a reference example 2, a case where a composite grinding machine described in US Pat. No. 5,392,566 is applied is taken as an example. I will give you. The production line in Reference Example 2 has the same configuration as the production line shown in FIG. 4 described in this embodiment, and the above-described composite grinding machine 1 is replaced with the composite grinding machine described in the publication. In the composite grinding machine as Reference Example 2, the radius of the grinding wheel for roughing in the roughing process is the minimum value R1 of the radius of curvature of the concave curved surfaces W1 and W2 on the cam outer peripheral surface of the camshaft that is the workpiece W. The radius of the grinding wheel for finishing in the finishing process is made smaller than the minimum value R1 of the radius of curvature.

<Comparison between this embodiment and Reference Examples 1 and 2>
Regarding this embodiment and Reference Examples 1 and 2, the cycle time and tool cost of the production line will be examined. For each of the present embodiment and Reference Examples 1 and 2, FIGS. 6A to 6C show the machining allowance and grinding time of the roughing process, and the finishing allowance and grinding time of the finishing process. . Here, the grinding time of each step in the present embodiment and the reference example 2 is a time obtained by dividing the grinding time by the respective complex grinders by two, which is the number of complex grinders. This is the time required for the roughing process and the finishing process for the object W. On the other hand, since each process in Reference Example 1 is performed by a separate grinding machine, the grinding time of each process is the grinding time itself of the corresponding process.

  When this embodiment is compared with Reference Example 1, as can be seen from FIGS. 6 (a) and 6 (b), this embodiment has more machining allowance for the roughing process, and the grinding time for the roughing process becomes longer. The finishing allowance for the finishing process is small, and the grinding time for the finishing process is shortened. Comparing the two, compared to the first embodiment, the present embodiment performs grinding as much as possible with the roughing grinding wheel 73, and the finishing allowance with the finishing grinding wheel 74 can be reduced as much as possible. I understand.

  In Reference Example 1, since the first grinding machine 130 in the roughing process and the second grinding machine 140 in the finishing process are separate, the grinding time by the first grinding machine 130 and the second grinding machine The machining conditions are set so that the grinding time by 140 is substantially the same. Due to this processing condition, finishing by the second grinding machine 140 dedicated to the finishing process is excessive as compared with the present embodiment.

  Further, comparing Reference Example 1 and Reference Example 2, as can be seen from FIGS. 6B and 6C, the reference example 1 has more machining allowance for the roughing process, and the grinding time of the roughing process is longer. It becomes longer, the finishing allowance of the finishing process is small, and the grinding time of the finishing process is shortened. When both are compared, the reference example 1 can be ground as much as possible with the roughing grinding wheel 73 and the finishing allowance with the finishing grinding wheel 74 can be reduced as much as possible in comparison with the reference example 2. I understand. This is considered to be because the roughing grinding wheel 73 can grind a larger amount by making the radius R2 of the roughing grinding wheel 73 smaller than the minimum value R1 of the curvature radius of the cam outer peripheral surface of the camshaft. .

  Next, the tool cost will be examined with reference to FIG. FIG. 7 shows tool costs for this embodiment and Reference Examples 1 and 2. Here, the “cost unit price ratio” in FIG. 7 is a cost ratio per grinding allowance φ1 mm between the roughing grinding wheel 73 and the finishing grinding wheel 74. The cost unit ratio of the roughing grinding wheel 73 and the finishing grinding wheel 74 is the number of workpieces W that can be ground per grinding wheel, the price of one grinding wheel, and one workpiece W. If the price of the grinding wheel and the workpiece W are calculated from the respective machining allowances, it will be about 1: 8 (= cost unit price of roughing grinding wheel 73: cost unit price of finishing grinding wheel 74). .

  As described in the second row from the bottom of FIG. 7, the cost ratio of the finishing grinding wheel 74 in the present embodiment can be greatly reduced as compared with the reference example 1, and compared with the reference example 2. It turns out that it can reduce very significantly. On the other hand, the cost ratio of the roughing grinding wheel 73 in the present embodiment is increased compared to the reference examples 1 and 2, but is very small compared to the difference in the cost ratio of the finishing grinding wheel 74. . Therefore, when viewed as the total cost ratio, the total cost ratio of the present embodiment can be significantly reduced compared to the total cost ratio of Reference Example 1, and is extremely large compared to the total cost ratio of Reference Example 2. It can be seen that it can be reduced.

<Others>
In the said embodiment, it was set as the structure which fixed the workpiece W supported by the support apparatus 20 with respect to the bed 10 by making the composite grinding machine 1 into a whetstone traverse type, and the grindstone support apparatus 60 traverse-feeding. In addition, the present invention is similarly applied to a configuration in which a table on which the support device 20 of the composite grinding machine 1 is placed is traverse-feeded and the composite grinding wheel base 62 is moved only in the X-axis direction with respect to the bed 10. it can.
Moreover, in the said embodiment, the workpiece W was demonstrated as the cam shaft and the grinding site | part was demonstrated as the cam outer peripheral surface. In addition, the present invention can also be applied to a grinding portion of the workpiece W on a cylindrical outer peripheral surface, for example, a crank journal of a crankshaft.

DESCRIPTION OF SYMBOLS 1: Compound grinder, 10: Bed, 11: Grinding wheel guide rail 12: Grinding wheel Z-axis ball screw, 13: Grinding wheel Z-axis motor 20: Support device, 21: Spindle head, 22: Tailstock 60: Whetstone support device, 61: Whetstone traverse base, 62: Compound whetstone base 71: Whetstone head main body, 72: Whetstone head turning mechanism, 73: Whetstone for rough machining 74: Whetstone for finishing, 75, 76: Whetstone rotation motor, 80: Control device W: Workpiece (camshaft), W1, W2: Concave curved surface

Claims (5)

A support device for supporting the workpiece;
A composite grinding wheel table including a roughing grinding wheel and a finishing grinding wheel that are arranged to be movable relative to the support device and can be selectively used;
A control device for grinding the workpiece by selectively using the roughing grinding wheel and the finishing grinding wheel;
In a grinding method using a composite grinding machine comprising:
A roughing step of roughing the workpiece using the roughing grinding wheel so as to leave a set finishing allowance in a state where the workpiece is supported by the support device;
After the roughing step, in a state where the workpiece is continuously supported by the support device, a finishing step for performing a finishing process so as to remove the finishing allowance using the finishing grinding wheel,
Run
The finishing allowance is set based on at least one of the amount of thermal displacement of the composite grinding machine and the amount of change in grinding resistance caused by the roughing grinding wheel,
A grinding method using a composite grinding machine in which a shape in which the finishing allowance is left in the workpiece is a shape that does not depend on the shape of the roughing grinding wheel. In claim 1,
In the production line, a plurality of the composite grinding machines are arranged between one pre-process and one post-process,
Each of the composite grinders sequentially performs the roughing process and the finishing process on the workpiece conveyed from the previous process of the manufacturing line, and the workpiece after the finishing process. Discharged to the subsequent process of the production line,
A grinding method using a composite grinding machine, wherein the plurality of composite grinding machines are executed in parallel between the pre-process and the post-process. In claim 1 or 2,
The grinding part of the workpiece is formed in a cam shape,
The finishing allowance is a grinding method using a composite grinder that is set based on a cam profile grinding error caused by a bending deformation amount of the workpiece or the composite grinder due to grinding resistance. In claim 3,
The grinding portion of the workpiece is formed in a cam shape having a concave curved surface with a radius of curvature R1 on the outer peripheral surface,
A grinding method using a composite grinding machine in which a radius R2 of the roughing grinding wheel and a radius R3 of the finishing grinding wheel are smaller than a curvature radius R1 of the concave curved surface. A support device for supporting the workpiece;
A composite grinding wheel table including a roughing grinding wheel and a finishing grinding wheel that are arranged to be movable relative to the support device and can be selectively used;
A control device for grinding the workpiece by selectively using the roughing grinding wheel and the finishing grinding wheel;
In a composite grinding machine comprising:
The controller is
In a state where the workpiece is supported by the support device, a finishing allowance set based on at least one of a thermal displacement amount of the composite grinding machine and a grinding resistance change amount caused by the roughing grinding wheel is left. The roughing is performed on the workpiece using the roughing grinding wheel,
A composite grinding machine that performs finishing processing so as to remove the finishing allowance using the finishing grinding wheel after the roughing.

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