Grinding device for gear grinding wheel, grinding method for gear grinding wheel using said device, and gear grinding method using gear grinding wheel

Abstract

[Problem] To provide: a grinding device for a gear grinding wheel capable of efficiently reducing, at the stage of finishing, the periodicity of a cumulative pitch error waveform causing meshing vibration or the like when a gear meshes with another gear and rotates; a grinding method for the gear grinding wheel using said device; and a gear grinding method using the gear grinding wheel. [Solution] A grinding device 100 for a gear grinding wheel, which is for grinding a grinding wheel 94, comprises: a main shaft 10 that holds a dress gear 90 and is rotationally driven; and an auxiliary shaft 20 that is disposed parallel to the main shaft 10. The main shaft 10 has a first gear 40 and a second gear 50, and the auxiliary shaft 20 has a third gear 60 meshing with the first gear 40 and a fourth gear 70 meshing with the second gear 50. At least one of the first gear 40 to the fourth gear 70 serves as a correction gear. The correction gear has, for example, a periodic cumulative pitch error waveform having the same period as the period of a cumulative pitch error waveform of a gear to be ground by the grinding wheel 94, and the cumulative pitch error waveform is transferred to the grinding wheel 94. [Selected drawing] Fig. 1

Description

Gear grinding device for a grinding wheel, grinding method for a gear grinding wheel using the device, and grinding method for a gear using the gear grinding wheel

[0001] The present invention relates to a gear grinding wheel grinding device, a grinding method for a gear grinding wheel using the device, and a grinding method for a gear using the gear grinding wheel, and particularly to a gear grinding wheel grinding device for finishing a tooth surface, a grinding method for a gear grinding wheel using the device, and a grinding method for a gear using the gear grinding wheel.

[0002] Conventionally, gears are used in various devices such as transmission devices. After processing the material, the gear undergoes pre-processes such as a gear cutting process, heat treatment, and further a grinding process for a reference surface, and then honing, which is a finishing process using a grinding wheel, is performed to achieve precise finishing of the tooth surface. The finishing process is carried out, for example, by holding a gear as a workpiece at one end of a rotating shaft and bringing the tooth surface of the workpiece into contact with a grinding wheel, and rotating the rotating shaft by a rotation driving means.

[0003] In the pre-process of the finishing process as described above, in the process of performing various grindings on the workpiece, due to the mounting error of the workpiece on the processing equipment, there may be a state where the center hole of the gear as the workpiece is displaced from the processing center, that is, a so-called core displacement state.

[0004] Fig. 20 shows such a core displacement state. The magnitude of the displacement is shown exaggerated compared to the actual scale. The original center of the gear as the workpiece is the intersection part C1 of the line L1 indicated by the dashed-dotted line, but in the mounted state, the intersection part C2 of the line L2 indicated by the dashed line is the center. When the workpiece clamped to the processing machine in such a state is rotated and processed around the center C2, that is, processed in a core displacement state, a pitch error occurs in the tooth surface of the processed gear. This pitch error appears as a cumulative pitch error of a sine wave with periodicity during the rotation of the gear, and the waveform indicating the cumulative pitch error in the entire circumferential tooth surface area (hereinafter simply referred to as the "cumulative pitch error waveform") has periodicity.

[0005] Furthermore, gears can also experience distortion in their shape due to processes other than grinding, such as the holding method during the heat treatment process, which is a pre-finishing step. For example, if a gear is suspended and held by passing a support rod through the central hole of the workpiece, the outer circumference of the workpiece may become slightly elliptical rather than perfectly circular. Moreover, if the inner circumference of the workpiece is supported from below and the workpiece is placed horizontally, the outer circumference may sag, causing the workpiece to become curved rather than flat.

[0006] Furthermore, if multiple cavities are provided on the inner circumference of the workpiece to remove material, the outer circumference of each cavity will contract towards the center of the workpiece compared to the areas without cavities, resulting in a circular shape that is not a perfect circle but a periodically undulating circle. Such distortion of the workpiece shape manifests as a cumulative pitch error of a sine wave with n periods (where n is a natural number), such as 1 period, 2 periods, etc., around the entire circumference.

[0007] As described above, misalignment due to mounting errors of workpieces to processing equipment, and shape distortion related to the heat treatment process of the gears, ultimately remain as a periodic cumulative pitch error waveform of the gear, causing phenomena such as deterioration of meshing vibration.

[0008] Patent Document 1 discloses a technique for reducing noise when gears mesh with each other. In a gear having multiple teeth, a set of continuously arranged teeth is shown, and such a set has differences in the shape and / or pitch of adjacent teeth, and one or more such sets are repeated. With this configuration, when the gears mesh with each other and rotate, non-uniformity occurs in the time difference in which each tooth meshes in sequence, resulting in larger non-integer noise and a smaller noise gap. As a result, the meshing sound generated when gears rotate while meshing with each other is less likely to be perceived as noise by the human ear, as it was in the past.

[0009] Japanese Patent Publication No. 2023-95160

[0010] However, the technology described in Patent Document 1 concerns adjustment techniques for when completed gears are actually assembled and mesh together. In other words, while the technology in that document aims to solve the problem of noise during the rotation of the finally installed gears, it does not attempt to make any corrections to tooth shape problems that occur during the finishing process of the gears. Therefore, it does not help to solve problems based on pitch errors in the processed gears caused by misalignment or distortion during manufacturing in finishing processes such as honing of gears, and the challenge of reducing the periodic cumulative pitch error waveform of the workpiece during the above-mentioned finishing process remains.

[0011] The present invention has been made in view of the above problems, and its purpose is to provide a gear grinding device, a gear grinding method using the device, and a gear grinding method using the gear grinding device for reducing the periodicity of the cumulative pitch error waveform, which causes the generation of meshing vibrations when gears are mounted together due to the tooth shape accuracy of the gears, during the finishing stage.

[0012] To achieve the above objective, one embodiment of the present invention of a gear grinding wheel, a gear grinding wheel grinding method using the present invention, and a gear grinding wheel grinding method using the gear grinding wheel is a gear grinding wheel grinding device that rotatably holds a dress gear for grinding a grinding wheel for finishing a workpiece which is a gear, and grinds the surface of the grinding wheel by meshing the dress gear with the grinding wheel and rotating it, comprising: a main shaft to which rotational driving force is input at one end and capable of holding the dress gear at the other end; and at least one sub-shaft arranged parallel to the main shaft, wherein the main shaft has a first gear fixedly mounted near the one end and a second gear fixedly mounted near the other end, and the sub-shaft has a third gear fixedly mounted near the one end and meshing with the first gear, and a fourth gear fixedly mounted near the other end and meshing with the second gear. At least one of the first to fourth gears is a correcting gear having a cumulative pitch error waveform that causes fluctuations in the rotational movement of the dress gear held on the main shaft, and the correcting gear is characterized in that it has the same period as the period of the cumulative pitch error waveform of the gear that is being ground by the grinding wheel.

[0013] In this configuration, during the grinding stage of the grinding wheel for gear grinding by the dress gear, at least one of the first to fourth gears that transmit rotational motion between the two axes is selected as a corrective gear, and this corrective gear causes a variation in the rotational motion of the dress gear. This variation is applied by the cumulative pitch error waveform of the corrective gear, that is, a waveform showing the cumulative pitch error across the entire tooth surface. The cumulative pitch error waveform of the corrective gear is then transferred to the grinding wheel being ground by the dress gear with the added rotational variation.

[0014] In other words, the grinding wheel is given a shape that has the same period as the cumulative pitch error waveform of the gear, which is the final object to be ground. When grinding a gear using a grinding wheel with this shape, the cumulative pitch error waveforms of the gear and the grinding wheel are set to be out of phase with each other. This makes it possible to reduce the amplitude of the cumulative pitch error waveform of the gear.

[0015] According to the present invention, the gear grinding device, the gear grinding method using the device, and the gear grinding method using the gear grinding device, during the grinding stage of the gear grinding device with a dressing gear, the action of the correcting gear transfers a cumulative pitch error waveform having the same period as the cumulative pitch error waveform of the gear being processed to the grinding device. Then, when grinding the gear using the processed grinding device, the amplitude of the cumulative pitch error waveform of the gear can be reduced by adjusting the phase between the cumulative pitch error waveform of the gear and the cumulative pitch error waveform transferred to the grinding device.

[0016] This is a schematic diagram showing a gear grinding device according to an embodiment of the present invention. This is a perspective view of a dress gear used in the gear grinding device of Figure 1. This is a diagram showing the steps of a gear grinding method using the gear grinding device according to an embodiment of the present invention. This is a schematic diagram showing a gear grinding device using a gear grinding wheel according to an embodiment of the present invention. This is a diagram showing the steps of a gear grinding method using a gear grinding wheel according to an embodiment of the present invention. This is a diagram showing an example of the cumulative pitch error waveform of the workpiece in Figure 4. This is a diagram showing an example of the cumulative pitch error waveform of the corrected gear in the gear grinding device of Figure 1. This is a diagram showing an example of the cumulative pitch error waveform of the workpiece after finishing by the grinding device of Figure 4. This is a schematic diagram showing a gear grinding device according to another embodiment of the present invention. This is an enlarged explanatory diagram of the holding mechanism of the corrected gear in the gear grinding device of Figure 9. This is a waveform diagram showing another example of the cumulative pitch error waveform before finishing of a workpiece that is the target of the other embodiment. This is a waveform diagram explaining the cumulative pitch error waveform of the corrected gear included in the gear grinding device according to the other embodiment. This waveform diagram shows the cumulative pitch error waveform of a workpiece after finishing by a gear grinding device using a gear grinding wheel according to another embodiment. This waveform diagram shows another example of the cumulative pitch error waveform before finishing of another workpiece that is the target of the other embodiment. This waveform diagram explains the cumulative pitch error waveform of another modified gear equipped with a gear grinding device using a gear grinding wheel according to another embodiment. This waveform diagram shows the cumulative pitch error waveform of another workpiece after finishing by a gear grinding device using a gear grinding wheel according to another embodiment. This waveform diagram shows another example of the cumulative pitch error waveform before finishing of yet another workpiece that is the target of another embodiment. This waveform diagram explains the cumulative pitch error waveform of yet another modified gear equipped with a gear grinding device using a gear grinding wheel according to another embodiment. This waveform diagram shows the cumulative pitch error waveform of yet another workpiece after finishing by a gear grinding device using a gear grinding wheel according to another embodiment. This is an explanatory diagram of the misalignment state that occurs when a gear workpiece is mounted on the grinding device.

[0017] Hereinafter, a gear grinding device 100 according to an embodiment of the present invention will be described in detail based on the drawings.

[0018] Figure 1 is a schematic diagram showing the basic configuration of a gear grinding wheel grinding device 100 according to an embodiment of the present invention. In the figure, the gear grinding wheel grinding device 100 is a device that grinds a grinding wheel 94, which is used for honing the workpiece (gear) that is the final target of processing, using a dressing gear 90 which will be described later.

[0019] The gear grinding device 100 includes a main shaft 10, which is a rotating shaft, and a secondary shaft 20, which is a rotating shaft arranged parallel to the main shaft 10. The main shaft 10 and the secondary shaft 20 are rotatably held by a bearing device (not shown). In this embodiment, the main shaft 10 is provided with a first clutch 16 at approximately the center position, and the secondary shaft 20 is provided with a second clutch 26 at approximately the center position. These clutches have the function of switching the main shaft 10 and the secondary shaft 20 between a connected state and a disconnected state at their respective clutch positions.

[0020] One end of the main spindle 10 is a rotational force input section 12 to which rotational force is transmitted. It has a first gear 40 on one side of the first clutch 16 and a second gear 50 on the other side. The other end is a dress gear holding section 14 that holds the dress gear 90. The dress gear holding section 14 holds the dress gear 90, and the dress gear 90 rotates together with the main spindle 10. The rotational force input section 12 is connected to a spindle motor 92, which is a rotational force supply means provided on one side of the main spindle 10. The first gear 40 is located between the rotational force input section 12 and the first clutch 16 and rotates together with the main spindle 10.

[0021] Here, the dress gear 90 is mounted while measuring the amount of misalignment by meshing it with a master gear (not shown), making it possible to keep the amount of misalignment of the dress gear 90 relative to the dress gear holding portion 14 below a threshold. In order to measure the amount of misalignment, for example, in the dress gear 90 of this embodiment, as shown in Figure 2, a certain percentage of the tooth width region is designated as a diamond-free electroplated region 90-2 where grinding diamonds are not electroplated, and the base metal is exposed in this region. The central region of the dress gear 90 forms a diamond-electroplated region 90-1 where diamonds are electroplated. By meshing the master gear with the tooth portion of this diamond-free electroplated region 90-2, the amount of misalignment can be measured. In this embodiment, the threshold for the amount of misalignment is, for example, 3 μm. In Figure 2, an example is shown where the diamond-free electroplated region 90-2 is provided in the regions at both ends in the tooth width direction of the tooth surface of the dress gear 90, but it may be on either the left or right side in the tooth width direction.

[0022] On the other hand, the second gear 50 is located between the dress gear holder 14 and the first clutch 16, is fixed to the main shaft 10, and rotates together with the main shaft 10. The first gear 40 and the second gear 50 are formed as external gears. The selective switching of connection and disconnection between one side and the other side of the main shaft 10 by the first clutch 16 is controlled by a control unit (not shown). The rotational force input unit 12 may be provided between the first gear 40 and the first clutch 16, or it may be a gear attached to the main shaft 10 and driven by a motor 92.

[0023] The dress gear 90 grinds the grinding wheel 94 while being held by the dress gear holding part 14. Each tooth surface of the grinding wheel 94, which is formed as an internal gear, is held so as to be rotatable with the rotation axis of the grinding wheel 94 having a predetermined axial intersection angle with respect to the main shaft 10, and can be ground by the dress gear 90, which is an external gear.

[0024] Furthermore, the number of teeth on the grinding wheel 94 is an integer multiple of the number of teeth on the dress gear 90, and in this embodiment, it is set to 3 times.

[0025] The sub-shaft 20 has a third gear 60 on one side and a fourth gear 70 on the other side, flanking a second clutch 26. The third gear 60 and the fourth gear 70 are fixed to the sub-shaft 20 and rotate together with it. The first gear 40 and the third gear 60 mesh, and the second gear 50 and the fourth gear 70 mesh. The connection and disconnection of one side of the main shaft 10 by the first clutch 16 and the connection and disconnection of one side of the sub-shaft 20 by the second clutch 26 are performed by a control unit (not shown) or manually.

[0026] The first gear 40 and the third gear 60, as well as the second gear 50 and the fourth gear 70, which mesh with each other, are all formed with the same pitch circle diameter and the same number of teeth. At least one of the first gear 40 to the fourth gear 70 is a modification gear, which will be described later. For example, in this embodiment, the third gear 60 is the modification gear.

[0027] The corrective gear, the third gear 60, is formed such that its cumulative pitch error waveform has a predetermined periodicity.

[0028] The gear grinding device 100 transmits rotational motion via a correcting gear, thereby varying the rotational motion of the dressing gear 90 held on the main shaft, and grinding the grinding wheel 94. Note that the correcting gear is not limited to one; multiple gears can be used as correcting gears. Furthermore, multiple correcting gears can be prepared and installed for selectable use.

[0029] The operation and function of the gear grinding device 100, which is the basic configuration of the present invention as shown in Figure 1, will be described below.

[0030] First, the present invention operates with both the first clutch 16 and the second clutch 26 engaged. Therefore, in the embodiment of the present invention, it is permissible to use a continuous, integrated shaft as the main shaft 10 and sub-shaft 20, without the first clutch 16 and the second clutch 26.

[0031] In this embodiment, the third gear 60 is a correcting gear, and its cumulative pitch error waveform has periodicity as described above. The number of periods is the same as the number of periods of the cumulative pitch error waveform of the workpiece that is ultimately ground by the grinding wheel 94, and this cumulative pitch error waveform can be transferred to it.

[0032] In other words, in this embodiment, the rotational movement of the dress gear 90 held on the main shaft 10 is affected by the influence of the third gear 60, which has a periodic cumulative pitch error waveform. Since the amount of misalignment of the dress gear 90 is set to be below a threshold, a cumulative pitch error waveform having the same period as the cumulative pitch error waveform of the correcting gear is transferred to the grinding wheel 94.

[0033] The following describes, using a flowchart, how to grind a gear grinding wheel 94 using the gear grinding device 100 shown in Figure 1 above.

[0034] As shown in Figure 3, in the dress gear mounting process of step 1, the dress gear 90 is attached to the dress gear holding portion 14 of the main shaft 10.

[0035] Next, in the clutch switching process of step 2, the clutch switching operation is performed, and only the first clutch 16 is engaged. Then, in the misalignment adjustment process of step 3, the dress gear 94 is rotated only by the transmission path shown as A in Figure 1, the dress gear 94 is engaged with the master gear (not shown), the amount of misalignment between the dress gear 90 and the main shaft 14 is measured, and this amount of misalignment is adjusted to be below a threshold.

[0036] Next, in the correction gear selection process of step 4, a correction gear is selected. This is done by selecting an appropriate gear from a pre-prepared set of gears with different cumulative pitch error waveforms when mounted on the shaft. For example, multiple correction gears with cumulative pitch error waveforms of varying amplitudes are prepared, and the one most suitable for reducing the amplitude corresponding to the cumulative pitch error waveform of the workpiece to be ground is selected.

[0037] Then, in the clutch switching process of step 5, the clutches are switched so that the first clutch 16 is disconnected and only the second clutch 26 is connected. As a result, only the transmission path shown as B in Figure 1 is formed. As described above, the function of the present invention can be achieved even if machining is performed with both the first and second clutches 16 and 26 connected, but by using only the above transmission path B, the rotational movement of the spindle 10 itself can be excluded, and the operation of the corrective gear can be made more precise.

[0038] In this state, the grinding wheel 94 is ground by the rotation of the dress gear 90 as part of the grinding process in step 6. By performing this grinding process, only the cumulative pitch error waveform of the corrected gear is transferred to the grinding wheel 94. In the final step, step 7, the dress gear removal process, the dress gear 90 is removed from the device.

[0039] This completes the transfer of the cumulative pitch error waveform to the grinding wheel for a predetermined number of cycles, i.e., the same number of cycles as the cumulative pitch error waveform of the gear that is the final object to be machined.

[0040] Next, the grinding of gears using the gear grinding wheel modified as described above will be explained. Figure 4 shows a schematic configuration diagram of the gear grinding device 110 using a gear grinding wheel in this embodiment. A gear 98 is attached in place of the dress gear 90 to the dress gear holding part 14 of the main shaft 10 of the gear grinding device 100 described above. Figure 5 shows a flowchart of the gear grinding method of the gear grinding device 110 using a gear grinding wheel.

[0041] In the workpiece mounting process of step 1, the gear 98 is attached to the dress gear holding part 14 of the main spindle 10.

[0042] In the clutch switching step of Step 2, the first clutch 16 is engaged, the second clutch 26 is disengaged, and the gear 98 is rotated only through the transmission path indicated by A in FIG. 4. In the cumulative pitch error measurement step of the next Step 3, the operator measures the cumulative pitch error waveform of the gear 98. The measurement is performed by rotating the gear 98 with the first clutch 16 engaged and the second clutch 26 disengaged and meshing with a master gear (not shown). The runout of the tooth groove is detected by the master gear, and from this, calculations of numerical values corresponding to the pitch error and the cumulative pitch error waveform are performed, and the cumulative pitch error waveform of the gear 98 can be obtained. A control unit (not shown) of the gear grinding device 110 using a gear grinding wheel calculates the pitch error amount of each tooth surface, the gear rotation angle position, the pitch period, etc. based on this measurement. Gears with a cumulative pitch error greater than a predetermined value are excluded as defective products.

[0043] In the phase alignment step of Step 4, the rotational angle positions of the gear 98 and the grinding wheel 94 are adjusted so that the phases of the cumulative pitch error waveform of the corrected grinding wheel 94 and the cumulative pitch error waveform of the gear 98 held on the main shaft 10 are shifted by approximately 1 / 2 cycle.

[0044] In the grinding step of Step 5, the grinding wheel 94 is rotated to grind the gear 98. The grinding wheel 94 has a cumulative pitch error waveform with the same number of cycles as the cumulative pitch error waveform of the gear 98, and the phase of the cumulative pitch error waveform of the corrected gear transferred to the grinding wheel 94 in Step 4 and the cumulative pitch error waveform of the gear 98 held on the main shaft 10 is set to be shifted by approximately 1 / 2 cycle. Therefore, when the gear 98 is ground using the grinding wheel 94 in this state, the amplitude of the cumulative pitch error waveform of the gear 98 is reduced, and the noise and vibration during the operation of the gear 98 are alleviated.

[0045] In the workpiece removal step of Step 6, the operator removes the gear 98. After that, when continuing to perform the grinding operation of another gear 98, a new gear 98 is attached, and Steps 2 to 4 described above are repeated. Thus, continuous grinding of all the gears 98 is performed.

[0046] Next, an explanation will be given as to how the cumulative pitch error waveform of the gear 98, which is the workpiece, is improved by the gear grinding method using the gear grinding wheel described above in the gear grinding apparatus 110.

[0047] As is well known, the cumulative pitch error amount of the gear 98 is measured by attaching the gear 98 to the spindle 10 and meshing it with a master gear (not shown). For example, when an attachment error due to core misalignment occurs in the pre-processing stage of the gear 98, as shown in FIG. 6, the cumulative pitch error waveform is a sine wave with one cycle per rotation. In the example shown in FIG. 6, the maximum value of the amplitude a of the cumulative pitch error waveform of the gear 98 is, for example, about 40 μm.

[0048] FIG. 7 shows an example of the cumulative pitch error waveform of the third gear 60, which is a modified gear, transferred to the grinding wheel 94. Here, the gear used has the same number of cycles per rotation of the cumulative pitch error waveform as that of the gear 98. In the present embodiment, the waveform has an amplitude slightly smaller than the amplitude of the cumulative pitch error waveform of the gear 98 described above.

[0049] And importantly, the cumulative pitch error waveform of the third gear 60 transferred to the grinding wheel 94 is set such that the phase is shifted by 1 / 2 with respect to the cumulative pitch error waveform of the gear 98 by the phase alignment in step 4 of FIG. 5 above. That is, the cumulative pitch error waveforms of the grinding wheel 94 and the third gear 60 have the same number of cycles, and by shifting the cycle by 1 / 2, the starting point of the peak of the cumulative pitch error waveform of the gear 98 and the starting point of the valley of the third gear 60 transferred to the grinding wheel 94 are aligned.

[0050] FIG. 8 shows the cumulative pitch error waveform of the gear 98 after grinding with the grinding wheel 94 having the waveform shown in FIG. 7 for the gear 98 having the cumulative pitch error waveform shown in FIG. 6. The cumulative pitch error waveform of the modified gear 98 has a sine wave waveform as shown in the figure, but its amplitude is small. By this modification, the periodicity of the cumulative pitch error waveform of the gear 98 is weakened, and the occurrence of vibrations during meshing when the finished gear is used is reduced.

[0051] Next, a gear grinding device 102 according to another embodiment of the present invention will be described. Figure 9 shows a gear grinding device 102 according to another embodiment. In this device, a gear holding mechanism 86 is provided that holds a plurality of third gears so that they can be selectively meshed with the first gear 40.

[0052] Figure 10 is an enlarged explanatory diagram of a gear holding mechanism 86 that holds the third gears 60, 62, and 64 provided on the sub-shaft 20. The gear holding mechanism 86 holds the three third gears 60, 62, and 64 and has a mechanism that allows the gear that meshes with the first gear 40 to be selected by sliding from among these three corrective gears. The third gears 60, 62, and 64 rotate together with the mounting portion of the sub-shaft 20 on one side of the sub-shaft 20, and are all formed with the same pitch circle diameter and the same number of teeth, but their cumulative pitch error waveforms are different, and by sliding, it is possible to mesh any one of them with the corresponding first gear 40. For example, the three third gears 60, 62, and 64 are each prepared with different cumulative pitch error waveform amplitudes and periods.

[0053] Furthermore, the third gears 60, 62, and 64 are fitted onto the key 82 provided on the sub-shaft 20, and are held securely on the sub-shaft 20 without any play, and are also held so as to be slidable along the key 82 on the sub-shaft 20.

[0054] A serration 84 is provided around the entire circumference of the sub-shaft 20 at a position opposite the first gear 40. The third gears 60, 62, and 64 can be fitted into the serration 84 by sliding, and in the fitted state, the rotational phase of the third gear can be detected via an encoder (not shown) provided on the motor 92. In this way, the gear holding mechanism 86 is composed of the sub-shaft 20, key 82, and serration 84.

[0055] The gear grinding device 102 can select the optimal gear from among the third gears 60, 62, and 64 to reduce the amplitude of the cumulative pitch error waveform of the workpiece 90, and mesh it with the first gear 40.

[0056] Furthermore, the gear holding mechanism that allows each of the multiple corrective gears to be selectively meshed on the sub-shaft 20 is sufficient as long as it is a mechanism that allows the multiple corrective gears to be replaced by some means and mounted on the sub-shaft 20 in a state where they mesh with the first gear 40. In other words, it is not limited to the sliding mechanism described above, and various mechanisms can be adopted, and the operator of the grinding device may also replace and install them manually.

[0057] In this embodiment, the third gear 60 is a corrective gear having a cumulative pitch error waveform of a 2-period sine wave. The third gear 62 is a corrective gear having a cumulative pitch error waveform that is not a regular 6-period sine wave, but a waveform that periodically repeats peaks and valleys. The third gear 64 is a corrective gear having a cumulative pitch error waveform that is a composite waveform, with a large 1-period waveform combined with a random waveform that contains irregular amplitudes. The operation and function of the gear grinding device 102 equipped with the three third gears 60, 62, and 64 configured as described above will be explained below.

[0058] First, Figure 11 shows the cumulative pitch error waveform of gear 98 detected based on the cumulative pitch error measured in step 3 above. As shown in the figure, gear 98 has two peaks, L1 and L2, and two valleys, M1 and M2, per rotation, and has a two-period sine wave. This two-period cumulative pitch error waveform is caused by distortion of gear 98 itself. In Figure 11, the actual magnitude of the amplitude a of the cumulative pitch error waveform of gear 98 is, for example, about 40 μm. Here, using the gear holding mechanism 86 shown in Figure 10 above, a third gear 60 having a waveform that matches the cumulative pitch error waveform of gear 98 is selected and meshed with the first gear 40.

[0059] Figure 12 shows the cumulative pitch error waveform of the third gear 60. As shown in the figure, the number of periods per revolution is the same as the sine wave of the cumulative pitch error waveform of gear 98. In this embodiment, the maximum value of the amplitude a of the cumulative pitch is approximately 20 μm. This cumulative pitch error waveform is transferred to the grinding wheel 94 by the gear grinding device 102. The cumulative pitch error waveforms of gear 98 and the third gear 60 are set with a phase shift of 1 / 2 by the phase alignment in step 4 of Figure 5. That is, the starting point of the peak of the cumulative pitch error waveform of gear 98 and the starting point of the trough of the cumulative pitch error waveform transferred to the grinding wheel 94 are aligned.

[0060] Figure 13 shows the cumulative pitch error waveform applied to the gear 98 when the grinding process of step 5 in Figure 5 is performed in this state. As shown in the figure, the amplitude of the two-period sine wave is approximately halved. In this way, the periodicity of the gear 98 is weakened, and the gear 98 finished in this manner exhibits low vibration when meshing with other gears in the mounted environment.

[0061] Next, Figure 14 shows the cumulative pitch error waveform of the other gear 98 measured in step 3 of Figure 5.

[0062] As shown in the figure, the cumulative pitch error waveform of gear 98 is a sine wave with six periods, consisting of six peaks (L1 to L6) and six troughs (M1 to M6), due to causes related to the heat treatment process, etc. This is caused, for example, by distortion that occurs during the manufacturing of gear 98 itself. In the figure, the actual magnitude of the amplitude a of the cumulative pitch error waveform of gear 98 is, for example, about 40 μm. Here, using the gear holding mechanism 86 shown in Figure 10, a third gear 62 having a waveform that matches the cumulative pitch error waveform of gear 98 is selected and meshed with the first gear 40.

[0063] Figure 15 shows the cumulative pitch error waveform of the selected third gear 62. As shown in the figure, it has the same 6 periods as the sine wave of the cumulative pitch error waveform of gear 98, and in this embodiment, the maximum amplitude of the cumulative pitch is about 20 μm. This cumulative pitch error waveform is transferred to the grinding wheel 94 by the gear grinding device 102. Then, the phase of these cumulative pitch error waveforms transferred to gear 98 and grinding wheel 94 is shifted by 1 / 2 through the phase alignment in step 5 above. That is, the starting point of the peak of the cumulative pitch error waveform of gear 98 and the starting point of the trough of the cumulative pitch error waveform transferred to grinding wheel 94 are aligned.

[0064] Figure 16 shows the cumulative pitch error waveform applied to the gear 98 when the cutting process of step 7 is performed in this state. As shown in the figure, the approximate sine wave with 6 periods has an amplitude of almost half. In this way, the periodicity of the gear 98 is weakened, and the gear 98 finished in this way will have low vibration when meshing with other gears when mounted.

[0065] Next, Figure 17 shows the cumulative pitch error waveform of yet another gear 98 measured in step 3 of Figure 5.

[0066] As shown in the figure, the gear 98 has a cumulative pitch error waveform, which is a sine wave with one period, depending on the state of misalignment that occurs when the gear 98 is mounted to the device. In the figure, the actual magnitude of the amplitude a of the cumulative pitch error waveform of the gear 98 is, for example, about 40 μm. Here, using the gear holding mechanism 86 shown in Figure 10, the third gear 64 having a waveform that matches the cumulative pitch error waveform of the gear 98 is selected and meshed with the first gear 40.

[0067] Figure 18 shows the cumulative pitch error waveform of the selected third gear 64. As shown in the figure, the cumulative pitch error waveform is a composite waveform that combines a large, one-period, out-of-phase fundamental waveform with a random waveform containing irregular amplitudes. This cumulative pitch error waveform is transferred to the grinding wheel 94 by the gear grinding device 102. Then, the phase of these cumulative pitch error waveforms transferred to the gear 98 and the grinding wheel 94 is set to be approximately shifted by 1 / 2 through the phase alignment process in step 5 of Figure 5.

[0068] Figure 19 shows the cumulative pitch error waveform applied to the gear 98 when the cutting process of step 7 is performed in this state. As shown in the figure, the cumulative pitch error waveform of the gear 98 is not only weakened in amplitude due to the composite wave of random waveforms, but also becomes a turbulent waveform with many dips and ridges. In this way, the periodicity of the gear 98 is further weakened, and the gear 98 finished in this way exhibits low vibration when meshing with other gears in the mounted state.

[0069] In the gear grinding method using the gear grinding wheel of this embodiment, a gear 98 is attached to the other end of the main shaft 10, the second clutch 26 is released, and only the first clutch 16 is engaged. The main shaft 10 is then rotated, and the gear 98 is ground by the grinding wheel 94 which has been ground by the dressing gear 90. The cumulative pitch error waveform of the gear 98 and the cumulative pitch error waveform of the corrected gear transferred to the grinding wheel 94 are shifted in phase by approximately 1 / 2 during the grinding of the gear 98 by the grinding wheel 94. As a result, the amplitude of the cumulative pitch error waveform of the gear 98 is reduced, and noise and vibration during the operation of the gear 98 are mitigated.

[0070] According to the gear grinding device 100 of this embodiment, during the grinding stage of the grinding wheel 94 for gear grinding by the dress gear 90, at least one of the first to fourth gears can be selected as a corrective gear, and this corrective gear can cause a variation in the rotational movement of the dress gear 90. That is, this variation means that a cumulative pitch error waveform with the same period number as the cumulative pitch error waveform of the workpiece (gear) that is the final target of processing is transferred from the corrective gear. Then, the cumulative pitch error waveform of the corrective gear is transferred to the grinding wheel 94 that is ground by the rotational movement of the corrected dress gear 90. This means that the grinding wheel 94 is given a form that can mitigate the amplitude of the cumulative pitch error waveform of the gear that is being ground.

[0071] Furthermore, the cumulative pitch error waveform of the corrected gear is a waveform that combines both a sine wave and a non-periodic waveform in which the pitch is formed unevenly. Therefore, the above waveform is transferred to the grinding wheel 94, and the gear 98 that is ground by this grinding wheel 94 has a reduced amplitude of the cumulative pitch error waveform and its periodicity can be more effectively broken. For example, a waveform that is a smooth sine curve due to misalignment becomes a distorted waveform with a small amplitude. As a result, the periodicity of the cumulative pitch error waveform of the gear 98 is reduced.

[0072] Furthermore, the correction gears are prepared with multiple gears having different cumulative pitch error waveforms, and the correction gears are interchangeable. This allows for the selection of the optimal correction gear according to the cumulative pitch error waveform present in gear 98, thereby improving the efficiency of the grinding wheel 94 dressing operation.

[0073] Furthermore, the main shaft 10 is fixedly mounted between the first gear 40 and the second gear 60 and has a first clutch 16 that can be switched between connecting and disconnecting the first gear 40 side and the second gear 50 side. The sub-shaft 20 is fixedly mounted between the third gear 60 and the fourth gear 70 and has a second clutch 26 that can be switched between connecting and disconnecting the third gear 60 side and the fourth gear 70 side. As a result, by engaging only the second clutch 26, it becomes possible to transfer the cumulative pitch error waveform of the corrected gear to the grinding wheel 94.

[0074] Furthermore, before grinding the surface of the gear 98, the second clutch 26 can be released, leaving only the first clutch 16 engaged, and the spindle 10 can be rotated to detect the amount of misalignment when the dress gear 90 is installed. This allows for adjustment to minimize the amount of misalignment, eliminating the transfer of unnecessary cumulative pitch errors to the grinding wheel 94 due to the misalignment of the dress gear 90.

[0075] According to the gear grinding method using a grinding wheel 94 ground by the gear grinding devices 100 and 102 of this embodiment, the rotational angle position of the gear 98 and the grinding wheel 94 is adjusted so that the phase between the cumulative pitch error waveform of the corrected gear transferred to the grinding wheel 94 and the cumulative pitch error waveform of the gear 98 held on the main shaft 10 is shifted by approximately 1 / 2 period. By grinding the gear 98 with this grinding wheel 94, the amplitude of the cumulative pitch error waveform of the gear 98 can be reduced.

[0076] Furthermore, by sequentially holding the gears 98 in the holding part 14 of the main spindle 10 without having to grind the grinding wheel 94 again, multiple workpieces 98 can be ground sequentially and efficiently.

[0077] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. For example, although the gear grinding device 100 for gear grinding wheels has a third gear 60 as the correcting gear, it is also permissible to use the first gear 40, the fourth gear 70, and the second gear 50 as correcting gears. Furthermore, there may be more than one correcting gear. That is, any multiple gears of the first gear 40, the third gear 60, the fourth gear 70, and the second gear 50 may each be correcting gears having a cumulative pitch error waveform for correction. In that case, the cumulative pitch error waveforms of the multiple correcting gears are combined and transmitted to the dressing gear 90 as a rotational force.

[0078] 10 Main shaft 12 Rotational force input section 14 Dress gear holding section 16 First clutch 20 Sub-shaft 26 Second clutch 40 First gear 50 Second gear 60 Third gear 62, 64 Additional third gear 70 Fourth gear 82 Key 84 Serration 86 Gear holding mechanism 90 Dress gear 92 Motor 94 Grinding wheel 98 Gear 100 Grinding device for gear grinding wheel according to embodiment 102 Grinding device for gear grinding wheel according to other embodiment 110 Grinding device for gear using gear grinding wheel according to embodiment

Claims

1. A grinding apparatus for gear grinding wheels that rotatably holds a dressing gear for grinding a grinding wheel for finishing a workpiece which is a gear, and grinds the surface of the grinding wheel by meshing the dressing gear with the grinding wheel and rotating it, comprising: a main shaft to which rotational driving force is input at one end and capable of holding the dressing gear at the other end; and at least one sub-shaft arranged parallel to the main shaft, wherein the main shaft has a first gear fixedly mounted near the one end and a second gear fixedly mounted near the other end, and the sub-shaft has a third gear fixedly mounted near the one end and meshing with the first gear, and a fourth gear fixedly mounted near the other end and meshing with the second gear, and at least one of the first to fourth gears is a correcting gear having a cumulative pitch error waveform that causes fluctuations in the rotational movement of the dressing gear held on the main shaft. The gear grinding device is characterized in that the corrected gear has the same period as the period of the cumulative pitch error waveform of the gear that is to be ground by the grinding wheel.

2. The gear grinding device according to claim 1, characterized in that the cumulative pitch error waveform of the corrected gear is a waveform obtained by combining both a sine wave and a non-periodic waveform in which the pitch is formed unevenly.

3. The gear grinding device according to claim 1 or 2, characterized in that a plurality of gears are prepared as the correcting gears, the main shaft and / or sub-shaft are provided with a gear holding mechanism that allows the plurality of correcting gears to be selectively meshed on the shafts, and the plurality of correcting gears are installed so that each has a different cumulative pitch error waveform.

4. A method for grinding a gear wheel using the gear wheel grinding apparatus described in claim 1, wherein the main shaft of the gear wheel grinding apparatus has a first clutch between the first gear and the second gear that switches one end of the main shaft from a connected state to a disconnected state, the sub-shaft has a second latch between the third gear and the fourth gear that switches one end of the sub-shaft from a connected state to a disconnected state, the connection of the first clutch is released and the rotational driving force is transmitted to the main shaft with only the second clutch connected, and the rotational force is transmitted in the order of the first gear, the third gear, the fourth gear, and the second gear to rotate the dress gear and grind the surface of the grinding wheel.

5. The method for grinding a gear grinding wheel according to claim 4, characterized in that, before performing the grinding process on the grinding wheel, the connection of the second clutch is released, leaving only the first clutch connected, and the amount of misalignment when the dress gear is installed is measured by rotating the main shaft, thereby enabling the correction of the misalignment when the dress gear is installed.

6. The method for grinding a gear grinding wheel according to claim 4, wherein a plurality of correcting gears are installed, each having a different cumulative pitch error waveform, and the main shaft and / or sub-shaft are provided with a gear holding mechanism that allows the plurality of correcting gears to be selectively meshed on the shafts, and the correcting gear is selected according to the cumulative pitch error of the workpiece to be ground.

7. A method for grinding a gear using a gear grinding wheel, wherein the grinding wheel is ground using a gear grinding apparatus described in claim 1, the method being characterized by: setting a grinding wheel on which the cumulative pitch error waveform of the corrected gear has been transferred to a predetermined position; attaching a workpiece which is a gear in place of the dress gear to the other end of the main spindle; adjusting the rotational angle position of the workpiece and the grinding wheel so that the phase of the cumulative pitch error waveform of the corrected gear transferred to the grinding wheel and the cumulative pitch error waveform of the workpiece held on the main spindle are shifted by approximately 1 / 2 period; and rotating the main spindle to grind the workpiece with the ground grinding wheel.

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