JP7225715B2 - Gear processing method and gear processing device - Google Patents

Description

The present invention relates to a gear machining method and a gear machining apparatus.

In Patent Document 1, while rotating the workpiece and the gear cutting tool synchronously, the workpiece is cut by performing a feed operation in the axial direction of the gear cutting tool with respect to the workpiece a plurality of times, thereby cutting the gear. is disclosed. When generating a gear on a workpiece with a gear cutting tool, it is required to suppress chatter vibration while improving machining efficiency.

In Patent Document 2, while performing cutting while changing the number of rotations (rotational speed) of the spindle, the fluctuation state of the vibration frequency of the spindle is monitored, and when the fluctuation of the vibration frequency exceeds a predetermined reference value, the spindle is disclosed. Further, in Patent Document 2, when the generation of regenerative chatter vibration is detected, the rotational speed of the main shaft is gradually decreased, and when the fluctuation of the vibration frequency exceeds a predetermined reference value, the rotational speed of the main shaft is detected. The detected rotation speed is defined as a stable rotation speed (stable rotation speed).

JP 2014-155990 A Japanese Patent Application Laid-Open No. 2015-217500

When trying to apply the technology described in Patent Document 2 to the technology described in Patent Document 1, since one feed operation of the gear cutting tool is short, the rotation of the gear cutting tool is stopped when regenerative chatter occurs. Even if the number is changed, there are cases where the feeding operation ends before the fluctuation of the vibration frequency exceeds the predetermined reference value, and the stable rotation speed cannot be detected.

On the other hand, in the technique described in Patent Document 1, even if regenerative chatter occurs during one feed operation, if there is still a grinding allowance remaining in the workpiece at that time, the gear cutting tool is not properly adjusted. By performing the cutting while rotating at the rotational speed, the workpiece can finally be a non-defective product. However, if cutting is continued in a state in which the proper rotational speed of the gear cutting tool cannot be grasped and the work becomes a defective product, the work will be discarded. In this regard, there is a demand for reducing the manufacturing cost by grasping the proper rotation speed of the gear cutting tool.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gear machining method and a gear machining apparatus capable of ascertaining an appropriate rotational speed of a tool, and to provide a gear machining method and a gear machining apparatus capable of reducing manufacturing costs. do.

A first gear machining method of the present invention is a state in which the rotation axis of the gear cutting tool is inclined with respect to a line parallel to the rotation axis of the workpiece, and the gear cutting tool and the workpiece are rotated synchronously. By performing the feeding operation of the gear cutting tool in the direction of the rotation axis of the object a plurality of times, the workpiece is cut to create a gear. The gear machining method includes a vibration measurement step of measuring vibration of the gear cutting tool generated during cutting, and a frequency analysis of the vibration of the gear cutting tool measured in the vibration measurement step to determine whether chatter vibration has occurred. a chatter determination step for determining whether or not chatter vibration has occurred, and when it is determined that chatter vibration has occurred, the gear cutting is performed with a cutting depth larger than the cutting depth when chatter vibration occurs and when chatter vibration occurs. A chatter machining process in which cutting is performed while continuously accelerating or decelerating over a predetermined range including the rotation speed of the tool to generate chatter vibration, and a frequency analysis of the vibration of the gear cutting tool measured in the chatter machining process. and a detection step of detecting the rotation speed when the amount of frequency variation exceeds a predetermined amount.

A first gear machining apparatus of the present invention is a state in which the rotation axis of the gear cutting tool is inclined with respect to a line parallel to the rotation axis of the workpiece, and the gear cutting tool and the workpiece are synchronously rotated, By performing the feeding operation of the gear cutting tool in the direction of the rotation axis of the object a plurality of times, the workpiece is cut to create a gear. The gear machining apparatus includes a vibration measuring device that measures vibration of the gear cutting tool, and a control device that controls cutting. The control device performs a frequency analysis of the vibration of the gear cutting tool measured by the vibration measuring device, and a chatter determination unit that determines whether or not chatter vibration has occurred; When it is determined that it has occurred, the depth of cut is larger than the depth of cut when it is determined that chatter vibration has occurred, and a predetermined range including the rotation speed of the gear cutting tool when chatter vibration occurs A chattering machining control unit that performs cutting while continuously accelerating or decelerating over a period of time to generate chattering vibration; and a proper rotation speed detection unit that performs frequency analysis and detects the rotation speed when the amount of frequency variation exceeds a predetermined amount.

Further, in the second gear machining method of the present invention, the gear cutting tool and the workpiece are synchronously rotated while the rotation axis of the gear cutting tool is inclined with respect to a line parallel to the rotation axis of the workpiece. By performing the feeding operation of the gear cutting tool in the direction of the rotation axis of the workpiece a plurality of times, the workpiece is cut to create a gear. The gear machining method includes a vibration measurement step of measuring vibration of the gear cutting tool generated during cutting, and a frequency analysis of the vibration of the gear cutting tool measured in the vibration measurement step to determine whether chatter vibration has occurred. a chatter determination step for determining whether or not chatter vibration has occurred, and when it is determined that chatter vibration has occurred, the gear cutting is performed with a cutting depth larger than the cutting depth when chatter vibration occurs and when chatter vibration occurs. A chatter machining process in which cutting is performed while continuously accelerating or decelerating over a predetermined range including the rotation speed of the tool to generate chatter vibration, and a frequency analysis of the vibration of the gear cutting tool measured in the chatter machining process. a detection step of detecting the rotation speed when the amount of frequency variation exceeds a predetermined amount; and a re-machining step of re-cutting the workpiece.

In the second gear machining apparatus of the present invention, the gear cutting tool and the workpiece are synchronously rotated in a state in which the rotation axis of the gear cutting tool is inclined with respect to a line parallel to the rotation axis of the workpiece. By performing the feeding operation of the gear cutting tool in the direction of the rotational axis of the gear cutting tool a plurality of times, the workpiece is cut and a gear is created. The gear machining apparatus includes a vibration measuring device that measures vibration of the gear cutting tool, and a control device that controls cutting. The control device performs a frequency analysis of the vibration of the gear cutting tool measured by the vibration measuring device, and a chatter determination unit that determines whether or not chatter vibration has occurred; When it is determined that the Perform cutting while accelerating or decelerating, and perform frequency analysis of the vibration of the gear cutting tool measured by the vibration measurement device during the cutting by the chatter generation machining control unit that generates chatter vibration and the chatter generation processing control unit. , a proper rotation speed detection unit for detecting a rotation speed when the amount of frequency variation exceeds a predetermined amount; a remachining control unit that rotates the gear cutting tool at the rotation speed detected by the proper rotation speed detection unit while making the cutting depth smaller than that during cutting by the part.

According to the first and second gear machining methods and the first and second gear machining apparatuses of the present invention, the chatter machining process and the chatter generation machining control unit control the cutting depth when it is determined that chatter vibration has occurred. By performing cutting with a depth of cut greater than the depth of cut, it is possible to reliably generate chatter vibration. Then, the detection process and the proper rotation speed detection unit can detect a rotation speed at which the amount of frequency fluctuation exceeds a predetermined amount in the cutting performed in one feeding operation, and the detected rotation speed is used for appropriate gear cutting. It can be derived as the rotational speed of the tool. Therefore, the first and second gear machining methods and the first and second gear machining apparatuses can grasp the proper rotational speed of the gear cutting tool by one feed operation.

In addition to this, according to the second gear machining method and the second gear machining apparatus, the remachining process and the remachining control unit perform cutting on the workpiece that has been cut by the chattering process and the chattering machining control unit. process. At this time, the remachining process and the remachining control unit reduce the depth of cut compared to that during cutting by the chatter machining process and the chatter generation machining control unit, and the gear cutting tool is rotated at the rotation speed detected by the appropriate rotation speed detection unit. Since cutting is performed while rotating, chatter vibration can be suppressed. As a result, the second gear machining method and the second gear machining apparatus can finally make the workpiece, which has been cut by the chattering process and the chattering occurrence machining control unit, a non-defective product. Therefore, the second gear machining method and the second gear machining apparatus can reduce the number of workpieces that are discarded as defective products, thereby reducing manufacturing costs.

1 is a perspective view of a gear machining apparatus according to one embodiment of the present invention; FIG. It is an enlarged view of the gear cutting tool fixed to the rotary spindle. FIG. 4 is a diagram showing the motion of the gear cutting tool and the workpiece during skiving; It is a block diagram of a control device. FIG. 5 is a diagram comparing a stability limit diagram with a graph showing the relationship between the rotational speed of the gear cutting tool and the chatter vibration frequency. 4 is a flowchart showing vibration analysis processing executed by the control device; It is a graph which shows the relationship between the rotational speed of a gear cutting tool and chatter vibration frequency when cutting is performed, accelerating the rotational speed of a gear cutting tool from SSR1 to SSR2.

Embodiments to which the gear machining method and gear machining apparatus according to the present invention are applied will be described below with reference to the drawings. First, with reference to FIGS. 1 to 3, an outline of a gear machining apparatus 1, which is an embodiment of the present invention, will be described.

(1. Outline of Gear Machining Device 1)
As shown in FIG. 1, the gear machining apparatus 1 has three mutually orthogonal rectilinear axes (X-axis, Y-axis and Z-axis) and three rotating axes (A-axis, B-axis and C-axis) as drive axes. It is a machining center with The gear machining apparatus 1 mainly includes a bed 10, a column 20, a saddle 30, a rotary main shaft 40, a table 50, a tilt table 60, a rotary table 70, a holding section 80, and a control device 100. .

Bed 10 is arranged on the floor. A column 20 and an X-axis motor 21 (see FIG. 4) are provided on the upper surface of the bed 10, and the column 20 is driven by the X-axis motor 21 to be movable in the X-axis direction (horizontal direction). be provided. Further, a saddle 30 and a Y-axis motor 31 (see FIG. 4) are provided on the side surface of the column 20, and the saddle 30 is provided so as to be movable in the Y-axis direction (vertical direction) by the Y-axis motor 31. The rotary main shaft 40 is rotatable by a main shaft motor 41 (see FIG. 4) housed in the saddle 30 . A gear cutting tool 42 is fixed to the tip of the rotation main shaft 40 , and the gear cutting tool 42 rotates as the rotation main shaft 40 rotates. The configuration of the drive shaft is not limited to the configuration described above, and may be changed as appropriate depending on the object to be machined, the installation design of the gear machining apparatus, and the rigidity design.

The gear cutting tool 42 will now be described with reference to FIG. As shown in FIG. 2, the gear cutting tool 42 is a skiving cutter having a plurality of blades 42a on its outer peripheral surface, and the end face of each blade 42a constitutes a rake face having a rake angle γ. The rake face of each blade 42a may be tapered around the central axis of the gear cutting tool 42, or may be formed in a surface shape facing in a different direction for each blade 42a.

Returning to FIG. 1, the description is continued. A table 50 and a Z-axis motor 51 (see FIG. 4) are provided on the upper surface of the bed 10 . The table 50 is provided so as to be movable in the Z-axis direction (horizontal direction) by a Z-axis motor 51 . A pair of tilt table support portions 61 that support the tilt table 60 are provided on the upper surface of the table 50 . A tilt table 60 is provided between the pair of tilt table support portions 61 so as to be swingable about an A axis (horizontal direction) parallel to the X axis. The tilt table 60 is driven by a tilt motor 62 (see FIG. 4) provided in the tilt table support portion 61 to swing about the A axis.

Further, a table motor 71 (see FIG. 4) is provided on the bottom surface of the tilt table 60, and the rotary table 70 is rotatable around a B axis perpendicular to the A axis by the table motor 71. As shown in FIG. A holding part 80 for holding the workpiece W is mounted on the rotary table 70 . The control device 100 controls cutting. Note that the control device 100 will be described later in detail.

(2. Operation of gear machining apparatus 1 during cutting)
Next, the operation of the gear machining apparatus 1 during cutting will be described. The gear machining apparatus 1 creates gears on a workpiece W by skiving. As shown in FIGS. 1 and 3 , the gear machining apparatus 1 swings the tilt table 60 around the A axis so that the B axis, which is the rotation axis of the workpiece W, is shifted to the rotation axis C of the gear cutting tool 42 . be inclined with respect to the parallel lines of The angle of inclination of the rotation axis C of the gear cutting tool 42 with respect to the rotation axis (B-axis) of the workpiece W is called an intersection angle δ. Then, the gear machining apparatus 1 feeds (relatively moves) the gear cutting tool 42 in the B-axis direction while synchronously rotating the workpiece W and the gear cutting tool 42. A workpiece W is cut to create a gear.

In skiving, the rotation speed V1 of the workpiece W and the rotation speed V2 of the gear cutting tool 42 are determined based on the crossing angle δ and the cutting speed V3. The cutting speed V3 and the feed speed V4 of the gear cutting tool 42 with respect to the workpiece W are determined by the machining time (cycle time) required for gear machining, the specifications of the gear cutting tool 42, the material of the workpiece W, and the workpiece W It is set based on the torsion angle of the gear formed in the That is, the cutting speed V3 and the feed speed V4 are set to optimum speeds in consideration of the machining efficiency in gear machining, the tool life of the gear cutting tool 42, and the like.

(3. Control device 100)
Next, details of the control device 100 will be described with reference to FIG. As shown in FIG. 4, the control device 100 mainly includes a machining condition setting unit 110 that sets machining conditions for gear machining, and a drive control unit 120 that controls the driving of various motors.

The machining condition setting unit 110 mainly includes a machining program storage unit 111 , a rotation speed setting unit 112 , a feed speed setting unit 113 and a depth of cut setting unit 114 . The machining program storage unit 111 stores a machining program used when performing gear machining on one workpiece W. As shown in FIG. This machining program includes, for example, the number of feed operations (number of passes) of the gear cutting tool 42 in the direction of the rotation axis of the workpiece W, information on the cutting depth set for each feed operation, and the like.

The rotation speed setting unit 112 sets the rotation speed of the workpiece W and the gear cutting tool 42 during gear machining. The rotation speed of the gear cutting tool 42 is, for example, a stability limit speed derived based on a well-known stability limit diagram showing the relationship between the rotation speed of the gear cutting tool 42 and the limit depth of cut at which regenerative chatter occurs. set. The upper part of FIG. 5 shows a stability limit diagram created based on the natural frequency of the gear cutting tool 42, the cutting resistance, the dynamic rigidity of the machining point, etc. Based on this stability limit diagram, the tooth It is derived that the stability limit speeds of the cutting tool 42 are SS1, SS2, SS3 and SS4 in the rotation speed range shown in FIG.

5 is a graph showing the relationship between the rotational speed of the gear cutting tool 42 and the frequency of regenerative chatter vibration. This graph shows that the frequency of regenerative chatter vibration fluctuates abruptly on the boundary of the stability limit speed.

The feed speed setting unit 113 sets a feed speed V4 during gear machining. The depth of cut setting unit 114 sets the depth of cut (depth of cut) during gear machining. In this embodiment, the gear machining apparatus 1 performs three feed operations for one workpiece W based on the machining program stored in the machining program storage unit 111 . Then, the gear machining apparatus 1 performs rough machining in the first and second feeding operations among the three feeding operations, and performs finishing machining in the third feeding operation. In the machining program, the same rotational speed and feed rate are set for rough machining and finish machining, and the depth of cut is set smaller for finish machining than for rough machining.

The drive control section 120 mainly includes a tool rotation speed control section 121 , a workpiece rotation speed control section 122 and a position control section 123 . The tool rotation speed control unit 121 drives and controls the spindle motor 41 so that the gear cutting tool 42 rotates at the rotation speed set by the rotation speed setting unit 112 . The workpiece rotation speed control unit 122 drives and controls the table motor 71 so that the workpiece W rotates at the rotation speed set by the rotation speed setting unit 112 .

The position control unit 123 drives and controls the X-axis motor 21 , the Y-axis motor 31 , the Z-axis motor 51 and the tilt motor 62 . In this embodiment, the control device 100 drives and controls the X-axis motor 21, the Y-axis motor 31, the Z-axis motor 51, and the tilt motor 62 by one position control unit 123. The Y-axis motor 31, the Z-axis motor 51 and the tilt motor 62 may be driven and controlled separately.

The position control unit 123 then positions and adjusts the angle of the gear cutting tool 42 with respect to the workpiece W so that cutting is performed with the depth of cut set by the depth of cut setting unit 114 . Further, the position control unit 123 drives and controls the Z-axis motor 51 so that the gear cutting tool 42 is fed at the feed speed set by the feed speed setting unit 113 .

The gear machining apparatus 1 further includes a vibration measuring device 90 that measures vibration of the gear cutting tool 42 generated during cutting. The vibration measuring device 90 is, for example, an acceleration sensor attached to the rotation main shaft 40 .

The control device 100 includes a chatter determination unit 130 that determines whether or not chatter vibration has occurred based on the measurement result of the vibration measuring device 90 . The chatter determination unit 130 performs frequency analysis (Fourier analysis, etc.) of the vibration of the gear cutting tool 42 measured during cutting of the workpiece W, and monitors the amplitude of the frequency band in which regenerative chatter is expected to occur. As a result, when the amplitude exceeds a predetermined threshold, chatter determination unit 130 determines that chatter vibration has occurred.

The control device 100 also includes an analysis unit 140 that derives the proper rotational speed of the gear cutting tool 42 . When chatter vibration occurs in cutting performed under the machining conditions set in the machining condition setting part 110, the analysis part 140 determines the appropriate rotation speed of the gear cutting tool 42 in the subsequent cutting. derive

The analysis unit 140 includes a chattering machining control unit 141 and an appropriate rotational speed detection unit 142 . The chattering machining control unit 141 controls the driving of various motors under machining conditions different from those set in the machining condition setting unit 110 in cutting performed during one feeding operation, thereby intentionally suppressing chattering. generate vibration. In the present embodiment, the chattering machining control unit 141 continuously accelerates the rotation speed of the gear cutting tool 42 in the cutting (rough machining) performed in the second feed operation to cut the workpiece W (hereinafter referred to as (referred to as "chatter processing").

The proper rotation speed detector 142 detects the proper rotation speed of the gear cutting tool 42 . As shown in the upper graph (stability limit diagram) of FIG. The amount of loading increases when the rotation speed of the gear cutting tool 42 is at the stable limit speeds SS1, SS2, SS3 and SS4. That is, the gear machining apparatus 1 can improve machining efficiency by setting the rotation speed of the gear cutting tool 42 to the stable limit speed.

As shown in the lower graph of FIG. 5, the chatter vibration frequency fluctuates with changes in the rotation speed of the gear cutting tool 42, and also fluctuates sharply at the stability limit speed. Focusing on this point, the proper rotation speed detection unit 142 performs frequency analysis of the vibration of the gear cutting tool 42 measured during chatter machining, and detects the rotation speed when the amount of frequency variation exceeds a predetermined amount. That is, analysis unit 140 derives the rotation speed detected by appropriate rotation speed detection unit 142 as an actual stable rotation speed, and sets the derived stable rotation speed in rotation speed setting unit 112 .

In addition, the control device 100 corrects the machining conditions set in the machining condition setting unit 110 to cut the workpiece W that has been cut when it is determined that chatter vibration has occurred. A unit 150 is provided. The machining condition correction section 150 includes a re-machining control section 151 and a division processing control section 152 .

The remachining control unit 151 performs drive control of various motors so that the workpiece W becomes a non-defective product when cutting the workpiece W that has undergone chattering. The remachining control unit 151 adjusts the rotational speed of the gear cutting tool 42 to the appropriate rotational speed when performing the third cutting (finishing) on the workpiece W that has undergone chattering machining in the second feeding operation. The stable rotation speed detected by the detection unit 142 is set. In this case, the gear machining apparatus 1 can suppress the occurrence of chatter vibration during finishing. In addition, the gear machining apparatus 1 performs finish machining on the workpiece W that has been subjected to chattering processing, with the rotation speed of the gear cutting tool 42 set at an appropriate level, so that the workpiece W is finally a non-defective product. can be cut into As a result, the gear machining apparatus 1 can reduce the number of workpieces W to be discarded as defective products, thereby reducing the overall manufacturing cost.

After determining that chatter vibration has occurred in the cutting (rough machining) performed under the machining conditions set in the machining condition setting unit 110, the divisional machining control unit 152 cuts the workpiece W that has been subjected to the cutting. It controls the driving of various motors during processing. When there is a remaining number of feed operations (when cutting allowance remains), the divisional machining control unit 152 increases the remaining number of feed operations beyond the remaining number of feed operations determined based on the machining program. , to reduce the depth of cut for each feed operation.

In this manner, the divisional machining control unit 152 performs cutting by correcting the machining conditions so that the workpiece W that has been cut when chatter vibration occurs is a non-defective product. As a result, even when chatter vibration occurs, the gear machining apparatus 1 can reduce the possibility that the workpiece cut when the chatter vibration occurs is discarded as a defective product. It is possible to reduce the overall manufacturing man-hours.
(4: vibration analysis processing)

Next, vibration analysis processing executed by the control device 100 will be described with reference to the flowchart shown in FIG. The vibration analysis process analyzes the vibration measured during cutting of the workpiece W, and determines whether or not chatter vibration has occurred. Then, the vibration analysis processing obtains an appropriate rotation speed of the gear cutting tool 42 when it is determined that chatter vibration has occurred. In the vibration analysis process, the workpiece W that has been cut when chatter vibration occurs is cut again under machining conditions such that the workpiece W is finally a non-defective product.

As shown in FIG. 6, in the vibration analysis process, the control device 100 measures vibration of the gear cutting tool 42 generated during cutting of the workpiece W (S1: vibration measurement step). The cutting performed in the process of S1 is performed under the machining conditions set in the machining condition setting unit 110, and the rotation speed and the depth of cut of the gear cutting tool 42 are unchanged throughout one feed operation. do. Then, the chatter determination unit 130 performs frequency analysis of the measured vibration of the gear cutting tool 42 to determine whether or not chatter vibration has occurred (S2: chatter determination step). Note that the process of S2 is performed each time one feed operation is completed.

In the processing of S2, if it is determined that chatter vibration has not occurred (S3: No), there is no need to change the rotation speed set in the rotation speed setting unit 112, so the control device 100 continues this processing as it is. finish. If the feed operation performed in the process of S1 is not the last feed operation (rough machining), the control device 100 performs the next feed operation, and the cutting performed in the process of S2 is the last feed operation. If it is an operation (finishing), the workpiece W is replaced and a new workpiece W is cut.

On the other hand, if it is determined in the process of S2 that chatter vibration has occurred (S3: Yes), the divided machining control unit 152 controls the workpiece being cut (the workpiece that was cut when the chatter vibration occurred). W) is cut again (S4). The process of S4 is executed when the feed operation performed in the process of S1 is not the final feed operation (rough machining). In other words, if the cutting performed in the processing of S2 is the final feed operation (finishing), the processing of S4 is omitted because there is no cutting allowance left on the workpiece W.

Next, the control device 100 replaces the workpiece W (S5), and performs chatter machining on the new replaced workpiece W (S6: chatter machining process). In the present embodiment, since chatter machining is performed during the second feed operation, cutting during the first feed operation is performed under the machining conditions set in the machining condition setting unit 110 .

After the process of S6, the analysis unit 140 performs frequency analysis of the vibration of the gear cutting tool 42 measured in the chatter machining process of S6. Then, the appropriate rotation speed detection unit 142 determines the rotation speed when the amount of frequency variation exceeds a predetermined amount, that is, the tooth rotation speed when the frequency changes suddenly and the frequency curve is divided in the lower graph of FIG. The rotation speed of the cutting tool 42 is detected (S7: detection step). Then, the proper rotational speed detection section 142 resets the detected rotational speed in the rotational speed setting section 112 as the proper rotational speed of the gear cutting tool 42 (S8).

Here, the processing from S6 to S8 will be described with a specific example. For example, as machining conditions when chatter vibration occurs, the rotation speed of the gear cutting tool 42 set in the rotation speed setting unit 112 is SS3, and the cutting depth set in the cutting depth setting unit 114 is F1. do. In this case, in the processing of S6, the chattering machining control unit 141, for example, continuously accelerates the rotation speed of the gear cutting tool 42 from SSR1 to SSR2, which is within a range of ±3% of the rotation speed SS3. Chatter machining is performed while Further, in the process of S6, the chattering machining control unit 141 performs chattering machining with the depth of cut of the gear cutting tool 42 set to F2, which is 25% larger than F1, for example.

Then, as shown in FIG. 7, in the process of S7, the proper rotation speed detection unit 142 monitors the amplitude of the frequency band in which chatter vibration is expected to occur, and detects the rotation of the gear cutting tool 42 when the frequency suddenly changes. Speed SS3' is detected. Then, the appropriate rotation speed detection unit 142 resets the detected rotation speed SS3′ in the rotation speed setting unit 112 as the appropriate rotation speed of the gear cutting tool 42 in the process of S8.

Returning to FIG. 6, the description of the vibration analysis process is continued. After the process of S8, the re-machining control unit 151 performs finish machining ( re-processing) is performed again (S9: re-processing step), and this process ends. In this way, the gear machining apparatus 1 detects the rotation speed of the gear cutting tool 42 in the detection step of S7 when performing again the cutting of the workpiece W that has undergone chattering in the re-machining step of S9. Set to rotation speed. Therefore, the gear machining apparatus 1 can finally convert the chatter-processed workpiece W into a non-defective product, and can reduce the number of workpieces W discarded as defective products.

Here, the depth of cut during chatter machining is larger than the depth of cut set in the depth of cut setting unit 114 (the depth of cut in the second feed operation determined based on the machining program). , the depth of cut in the third feed operation (finishing) is the depth of cut set in the depth of cut setting unit 114 (the depth of cut in the third feed operation determined based on the machining program) also becomes smaller. On the other hand, it is necessary to leave a certain amount or more of cutting allowance on the workpiece W after chatter machining so that the machined surface that has become defective due to regenerative chatter generated in chatter machining can be finished in good condition. There is

Regarding this point, the chatter generating machining control unit 141 sets the depth of cut in the first feed operation to the depth of cut set in the depth of cut setting unit 114 (first feed determined based on the machining program). It may be smaller than the depth of cut in operation). As a result, the gear machining apparatus 1 can leave a certain amount or more of cutting allowance for the workpiece W after chatter machining, while ensuring the depth of cut in the second feeding operation. Therefore, the gear machining apparatus 1 can improve the machined surface, which has become defective due to regenerative chatter generated in chatter machining, by finishing machining, and the workpiece W subjected to chatter machining is finally a non-defective product. be able to.

Further, in this case, the chattering machining control unit 141 may divide the finishing machining performed after the chattering machining into two times, and divide the depth of cut in each feeding operation to make it smaller. As a result, the gear machining apparatus 1 can improve the surface properties of the machined surface of the workpiece W. As shown in FIG.

In this way, the chatter generating machining control unit 141 determines the machining conditions during chatter machining based on the machining conditions when chatter vibration occurs. That is, when chatter vibration occurs in cutting performed under the machining conditions set in the machining condition setting unit 110, the chatter generation machining control unit 141 sets the depth of cut during chatter machining to the depth of cut setting unit 114. Make it larger than the depth of cut set in . As a result, the chatter generating machining control unit 141 can easily generate chatter vibration in one chatter machining performed in one feed operation.

As a result, the proper rotational speed detection unit 142 can detect a rotational speed at which the amount of frequency fluctuation exceeds a predetermined amount in the cutting performed in one feed operation, and the detected rotational speed can be used as an appropriate gear cutting tool. can be derived as the rotational speed of In this way, the gear machining apparatus 1 can detect the appropriate rotational speed (stable limit speed) of the gear cutting tool 42 in chatter machining performed in one feeding operation, so that the stable limit speed can be grasped efficiently. be able to. Then, the re-machining control unit 151 performs finish machining while the gear cutting tool 42 is set to an appropriate rotational speed, so that the workpiece W that has been cut while generating chatter vibration in the chatter machining is finished as a final workpiece W. It can be regarded as a good product. Therefore, the gear machining apparatus 1 can reduce the number of workpieces W discarded as defective products, thereby reducing the overall manufacturing cost.

Further, the chatter generating machining control unit 141 accelerates the gear cutting tool 42 within a range of ±3% of the rotation speed set in the rotation speed setting unit 112 . As a result, the gear machining apparatus 1 can reduce the amount of change in the rotation speed of the gear cutting tool 42 in chatter machining performed in one feed operation. That is, chatter vibration may be suppressed when the rotation speed change (variation) is large. On the other hand, the gear machining apparatus 1 can avoid the suppression of chatter vibration by reducing the amount of change in the rotational speed of the gear cutting tool 42 . Further, the chatter generating machining control unit 141 changes the rotation speed of the gear cutting tool 42 around the rotation speed set in the rotation speed setting unit 112, thereby making it easier to generate chatter vibration.

In this embodiment, chatter machining is performed using a workpiece W other than the workpiece W determined to have chatter vibration when cutting under the machining conditions set in the machining condition setting unit 110. . In this case, the chattering machining control unit 141 can set machining conditions during chattering machining regardless of the cutting allowance remaining in the workpiece W that has been cut when chattering vibration occurs. Therefore, the gear machining apparatus 1 can secure a sufficient cutting allowance remaining in the workpiece W after chatter machining, so that the workpiece W subjected to chatter machining can finally be a non-defective product.

On the other hand, when chatter vibration occurs in the cutting performed under the machining conditions set in the machining condition setting unit 110, the gear machining apparatus 1 cuts the workpiece W when the chatter vibration occurs. If there is a cutting allowance remaining in the workpiece W, cutting is performed again under machining conditions such that the workpiece W is finally a non-defective product. At this time, the division processing control unit 152 cuts while performing the feed operation of the gear cutting tool 42 a plurality of times while making the depth of cut smaller than when chatter vibration occurs. As a result, the gear machining apparatus 1 can suppress the chatter vibration from occurring again, so that the workpiece W that has been cut when the chatter vibration has occurred can finally be a non-defective product.

(5. Others)
As described above, the present invention has been described based on the above embodiments, but the present invention is not limited to the above embodiments, and various modifications and improvements can easily be made without departing from the scope of the present invention. can be inferred. For example, in the present embodiment, the range in which the rotation speed of the gear cutting tool 42 is changed during chatter machining is set within ±3% of the rotation speed set in the rotation speed setting unit 112. As described above, the range in which the rotation speed of the gear cutting tool 42 is changed may be changed as appropriate.

For example, in the above embodiment, the case where one workpiece W is fed three times has been described as an example, but the present invention provides a gear machining apparatus and a gear machining method that perform a plurality of feed operations. can be applied to Further, in the above embodiment, the case where chatter machining is performed during the second feed operation has been described, but chatter machining may be performed during the first feed operation. In other words, chatter machining may be performed during a feed operation other than the last feed operation among the feed operations performed a plurality of times.

In addition, in the present embodiment, chatter machining is performed by cutting the workpiece W while accelerating the rotational speed of the gear cutting tool 42, but the workpiece W is cut while reducing the rotational speed of the gear cutting tool 42. may be cut. Furthermore, in the present embodiment, chatter machining is performed by continuously changing the rotational speed of the gear cutting tool 42, but the rotational speed of the gear cutting tool 42 may be changed stepwise. For example, the gear cutting tool 42 performs cutting while repeating rotation at a constant speed and rotation with acceleration. Measure the vibration of the tool 42 . In this case, the proper rotational speed detection section 142 can make it easier to accurately detect the proper rotational speed than in the case where the rotational speed of the gear cutting tool 42 is changed continuously.

In the above-described embodiment, when chatter vibration occurs during cutting under the machining conditions set in the machining condition setting unit 110, the analysis unit 140 performs chatter machining and increases the rotational speed of the gear cutting tool 42. Although the case of resetting is described, the present invention is not limited to this. For example, the control device 100 includes a counting section that counts the number of workpieces W that have been cut after chattering, and the analysis section 140 detects when the count value of the counting section reaches a predetermined number, i.e. When the number of workpieces W that have been cut after chatter machining reaches a predetermined number, chatter machining and the rotation speed of the gear cutting tool 42 may be reset.

In this case, the analysis unit 140 can periodically reset chatter machining and the rotation speed of the gear cutting tool 42 . In other words, it is conceivable that the actual stable limit speed may change due to aged deterioration of various parts of the gear machining apparatus 1, the gear cutting tool 42, and the like. On the other hand, the gear machining apparatus 1 can prevent chatter vibration from occurring by periodically reviewing the appropriate rotation speed.

1: Gear processing device 42: Gear cutting tool 90: Vibration measuring device 100: Control device 130: Chatter determination unit 141: Occurrence machining control unit 142: Proper rotation speed detection unit 151: Re-machining control unit , S1: vibration measurement process, S2: chatter judgment process, S6: chatter machining process, S7: detection process, S9: re-machining process, O: rotation axis of gear cutting tool, W: workpiece

Claims (8)

With the rotation axis of the gear cutting tool inclined with respect to a line parallel to the rotation axis of the workpiece, the gear cutting tool and the workpiece are rotated synchronously, and the gear cutting tool is rotated in the direction of the rotation axis of the workpiece. A gear machining method for cutting the workpiece and creating a gear by performing the feeding operation of a plurality of times,
a vibration measurement step of measuring the vibration of the gear cutting tool that occurs during cutting;
a chatter determination step of performing frequency analysis of the vibration of the gear cutting tool measured in the vibration measurement step and determining whether or not chatter vibration has occurred;
When it is determined that chatter vibration has occurred, the depth of cut is larger than the depth of cut when chatter vibration occurs, and over a predetermined range including the rotational speed of the gear cutting tool when chatter vibration occurs a chattering process of performing cutting while continuously accelerating or decelerating to generate chattering;
a detection step of performing frequency analysis of the vibration of the gear cutting tool measured in the chatter machining step, and detecting the rotation speed when the amount of frequency variation exceeds a predetermined amount;
A gear machining method comprising: With the rotation axis of the gear cutting tool inclined with respect to a line parallel to the rotation axis of the workpiece, the gear cutting tool and the workpiece are rotated synchronously, and the gear cutting tool is rotated in the direction of the rotation axis of the workpiece. A gear machining method for cutting the workpiece and creating a gear by performing the feeding operation of a plurality of times,
a vibration measurement step of measuring the vibration of the gear cutting tool that occurs during cutting;
a chatter determination step of performing frequency analysis of the vibration of the gear cutting tool measured in the vibration measurement step and determining whether or not chatter vibration has occurred;
When it is determined that chatter vibration has occurred, the depth of cut is larger than the depth of cut when chatter vibration occurs, and over a predetermined range including the rotational speed of the gear cutting tool when chatter vibration occurs a chattering process of performing cutting while continuously accelerating or decelerating to generate chattering;
a detection step of performing frequency analysis of the vibration of the gear cutting tool measured in the chatter machining step, and detecting the rotation speed when the amount of frequency variation exceeds a predetermined amount;
a re-machining step of re-cutting the workpiece cut in the chatter machining step at the rotation speed of the gear cutting tool detected in the detecting step;
A gear machining method comprising: The predetermined range in the chatter machining step is based on the rotation speed of the gear cutting tool set during cutting when it is determined in the chatter determination step that chatter vibration has occurred. The gear machining method according to claim 1 or 2, wherein the range is from -3% to +3% of the rotational speed . The gear machining method according to any one of claims 1 to 3, wherein the chatter machining step is performed using the workpiece that has undergone cutting when it is determined that chatter vibration has occurred. The chatter machining step is performed using the workpiece different from the workpiece that was cut when it was determined that chatter vibration occurred,
In the gear cutting method, the gear cutting tool is fed a plurality of times while reducing the depth of cut compared to when chatter vibration occurs on the workpiece that has been cut when chatter vibration occurs. 4. The gear machining method according to any one of claims 1 to 3, wherein cutting is performed while performing cutting to create a gear on the workpiece. The gear machining according to any one of claims 1 to 5, wherein the chattering process is executed when the number of workpieces cut after the last chattering process is executed reaches a predetermined number. Method. With the rotation axis of the gear cutting tool inclined with respect to a line parallel to the rotation axis of the workpiece, the gear cutting tool and the workpiece are rotated synchronously, and the gear cutting tool is rotated in the direction of the rotation axis of the workpiece. A gear machining device that cuts the workpiece and creates a gear by performing the feeding operation of a plurality of times,
The gear processing device is
a vibration measuring device for measuring vibration of the gear cutting tool;
a control device for controlling cutting;
with
The control device is
a chatter determination unit that performs frequency analysis of the vibration of the gear cutting tool measured by the vibration measuring device and determines whether or not chatter vibration has occurred;
Rotational speed of the gear cutting tool when the chatter vibration is determined by the chatter determination unit to be greater than the depth of cut when the chatter vibration occurs and when the chatter vibration occurs A chatter generation processing control unit that performs cutting while continuously accelerating or decelerating over a predetermined range to generate chatter vibration;
Frequency analysis of the vibration of the gear cutting tool measured by the vibration measurement device during cutting by the chatter generation processing control unit, and appropriate rotation speed detection for detecting the rotation speed when the amount of frequency fluctuation exceeds a predetermined amount. Department and
A gear machining device. With the rotation axis of the gear cutting tool inclined with respect to a line parallel to the rotation axis of the workpiece, the gear cutting tool and the workpiece are rotated synchronously, and the gear cutting tool is rotated in the direction of the rotation axis of the workpiece. A gear machining device that cuts the workpiece and creates a gear by performing the feeding operation of a plurality of times,
The gear processing device is
a vibration measuring device for measuring vibration of the gear cutting tool;
a control device for controlling cutting;
with
The control device is
a chatter determination unit that performs frequency analysis of the vibration of the gear cutting tool measured by the vibration measuring device and determines whether or not chatter vibration has occurred;
Rotational speed of the gear cutting tool when the chatter vibration is determined by the chatter determination unit to be greater than the depth of cut when the chatter vibration occurs and when the chatter vibration occurs A chatter generation processing control unit that performs cutting while continuously accelerating or decelerating over a predetermined range to generate chatter vibration;
Frequency analysis of the vibration of the gear cutting tool measured by the vibration measurement device during cutting by the chatter generation processing control unit, and detection of a proper rotation speed for detecting the rotation speed when the amount of frequency fluctuation exceeds a predetermined amount. Department and
Rotation detected by the proper rotation speed detection unit while making the depth of cut smaller than that during cutting by the chatter generation processing control unit for cutting the workpiece that has been cut by the chatter generation processing control unit. a remachining control unit that performs while rotating the gear cutting tool at a speed;
A gear machining device.

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