JP6165464B2 - Gear grinding machine - Google Patents

Description

  The present invention relates to a gear grinding device, and more particularly, to a gear grinding device for grinding a cycloid gear using a rotating grindstone.

2. Description of the Related Art Conventionally, a gear grinding apparatus that uses a grindstone to grind a roughened gear with a grindstone to perform a finishing process has been used.
For example, Patent Document 1 discloses a gear grinding apparatus that grinds a gear by relatively rotating the screw-shaped grindstone and the gear in a state of meshing with each other. This conventional gear grinding apparatus has a bed, and a column is supported on the bed so as to be movable in the horizontal direction. A saddle is supported on the column so as to be vertically movable, and a threaded grindstone is rotatably attached to the saddle. The bed is provided with a cylindrical table so as to face the threaded grindstone. In this table, a cylindrical work processing rotary shaft is supported so as to be rotatable about a vertical rotation axis. A workpiece gear is attached to the workpiece machining shaft.

  When the gear is ground by the conventional gear grinding apparatus, the workpiece gear is rotated by rotating the workpiece machining rotary shaft to which the workpiece gear is attached. Further, the column and saddle are driven while rotating the threaded grindstone to mesh the threaded grindstone with the workpiece gear. And a to-be-processed gear is finished to a predetermined dimension by advancing a screw-shaped grindstone toward a to-be-processed gear.

JP 2011-212762 A

  The gear grinding apparatus disclosed in Patent Document 1 described above is mainly used for grinding an involute gear. In the involute gear, the tooth tip surface does not come into contact with the tooth bottom surface of the counterpart gear in a meshed state with the counterpart gear. Therefore, high machining accuracy is not required for machining the outer periphery of the involute gear.

  On the other hand, there is also a desire to use a gear grinding device for grinding cycloid gears. The cycloid gear is formed on the basis of an abduction cycloid curve, which is the trajectory of an abduction circle in which the tooth profile of the tooth tip circumscribes the base circle and rolls without slipping. It is formed on the basis of an inversion cycloid curve that is a locus of a rolling inversion circle. In this cycloid gear, the outer periphery of the gear including the top of the tooth tip comes into contact with the tooth bottom of the mating gear when meshed with the mating gear. Therefore, in order to reduce the friction and vibration between the gears, it is required to process the outer periphery of the gears with higher dimensional accuracy than before.

Mechanical thermal displacement can be considered as a factor affecting the processing accuracy of the outer periphery of the gear. For example, the bed is thermally deformed due to changes in the temperature of the surrounding environment where the gear grinding machine is installed, or the temperature of the coolant used for cooling or lubrication during grinding, and the grinding wheel and workpiece rotation are rotated. The distance between the center and the shaft changes.
Moreover, when dressing a grindstone, the grindstone temperature rises due to frictional heat between the grindstone and the dressing tool, and the grindstone expands. That is, since the diameter of the grindstone changes between immediately after dressing and when it is not, the distance between the outer peripheral surface of the grindstone and the outer peripheral surface of the gear to be processed changes.
In order to achieve the accuracy required for the outer peripheral machining of the cycloid gear, it is necessary to correct the incision amount of the grindstone with respect to the cycloid gear that is the workpiece gear in consideration of these disturbance factors.

However, the gear grinding apparatus disclosed in Patent Document 1 described above does not assume grinding of a cycloid gear. That is, the apparatus of Patent Document 1 is based on the premise of grinding an involute gear that does not require higher machining accuracy than the conventional machining of the outer circumference of the gear, and grinds the outer circumference of the cycloid gear with higher machining accuracy than before. Since this is not envisaged, no consideration is given to how to correct the cutting depth of the grindstone for the cycloid gear that is the gear to be machined in consideration of mechanical thermal displacement of the bed and deformation of the grindstone.
Therefore, the conventional apparatus cannot be applied to the grinding of the cycloid gear, and new research or the like is required.

  The present invention has been made to solve the above-described problems of the prior art, and the outer periphery of the cycloid gear can be ground with high accuracy in consideration of disturbance factors such as mechanical thermal displacement. An object is to provide a gear grinding apparatus.

To achieve the above object, the gear grinding device of the present invention is a gear grinding device that performs grinding on a cycloid gear using a rotating grindstone, and a bed installed on the floor, supported by the bed, A gear holding portion that rotatably holds the cycloid gear at a processing position of the cycloid gear, and a grindstone holding portion that is supported by the bed at a position facing the gear holding portion, holds the grindstone, and A wheel holding unit that moves toward the cycloid gear held by the gear holding unit, and a probe supported by the wheel holding unit by moving the wheel holding unit is moved from the wheel side toward the cycloid gear side. Measuring the outer diameter of the cycloid gear by contacting the outer periphery of the cycloid gear and detecting the position of the probe at the time of contact. If, based on the outer diameter of the cycloid gear and is measured by the outer diameter measuring device, characterized in that it comprises a control unit for correcting the depth of cut of the grinding wheel relative cycloidal gear.
In the present invention configured as described above, the outer diameter measuring instrument measures the outer diameter of the cycloid gear, and based on the measurement result, the control unit corrects the cutting amount of the grindstone with respect to the cycloid gear. Even if an error occurs in the outer diameter of the cycloid gear with respect to the target dimension due to a disturbance factor such as, the cutting amount of the grindstone can be corrected according to the measurement result of the outer diameter of the cycloid gear reflecting the error. . Therefore, the outer periphery of the cycloid gear can be ground with high accuracy in consideration of disturbance factors such as mechanical thermal displacement.

In the present invention, preferably, the gear holding portion rotatably holds a master work serving as a reference for the outer diameter of the cycloid gear at the machining position, and the outer diameter measuring instrument is a master held by the gear holding portion. The outer diameter of the workpiece is measured, and the control unit calculates the difference between the outer diameter of the master workpiece and the outer diameter of the cycloid gear measured by the outer diameter measuring instrument, and based on this difference, the grinding stone is cut into the cycloid gear. Correct the amount.
In the present invention configured as described above, the control unit determines the cutting amount of the grindstone with respect to the cycloid gear based on the difference between the outer diameter of the master work and the outer diameter of the cycloid gear measured under common conditions by the outer diameter measuring instrument. Since the error of the outer diameter of the cycloid gear with respect to the target dimension is accurately reflected, the cutting amount of the grindstone can be corrected. Therefore, the outer periphery of the cycloid gear can be ground with higher accuracy.

Further, in the present invention, preferably, the gear holding portion includes a main shaft that rotates the cycloid gear at the machining position, and the outer diameter measuring device is a position of the measuring member when the measuring member is brought into contact with the outer periphery of the main shaft, The outer diameter of the cycloid gear is measured based on the position of the probe when the probe is brought into contact with the outer periphery of the cycloid gear.
In the present invention configured as described above, the position of the probe when the probe is brought into contact with the outer periphery of the spindle reflects the change in the distance between the grindstone holder and the spindle, and the probe is used as a cycloid gear. Since the outer diameter of the cycloid gear is reflected in addition to the change in the distance between the grindstone holding part and the main shaft at the position of the measuring element when contacting the outer periphery of the wheel, the outer diameter measuring part is It is possible to extract only the outer diameter of the cycloid gear without the influence of the distance change from the main shaft. Therefore, the outer diameter of the cycloid gear can be measured more accurately, and the outer periphery of the cycloid gear can be ground with higher accuracy.

Further, in the present invention, preferably, the outer diameter measuring instrument measures the outer diameter of the cycloid gear after the start of the next process after any of the plurality of processes included in the grinding of the cycloid gear, A control part correct | amends the cutting amount of the grindstone in the process after the following process based on the outer diameter of the cycloid gear measured by the outer diameter measuring device.
In the present invention configured as described above, the outer diameter measuring device measures the outer diameter of the cycloid gear that has undergone a part of the process included in the grinding process, and the control unit performs the subsequent process and the subsequent steps based on the measurement result. Since the cutting depth of the grinding wheel is corrected in the above process, even if there is an error in the outer diameter of the cycloid gear with respect to the target dimension due to disturbance factors during grinding, the outer diameter of the cycloid gear reflects the error. Depending on the result, the cutting amount of the grindstone after the next step can be corrected. Therefore, the outer periphery of the cycloid gear can be ground with high accuracy in consideration of disturbance factors such as mechanical thermal displacement.

  According to the gear grinding apparatus of the present invention, the outer periphery of the cycloid gear can be ground with high accuracy in consideration of disturbance factors such as mechanical thermal displacement.

1 is a perspective view of a gear grinding apparatus according to an embodiment of the present invention. It is a side view of the gear grinding apparatus by embodiment of this invention. It is a top view of the gear grinding apparatus by embodiment of this invention. FIG. 4A is a partially enlarged plan view of a workpiece holding unit and an outer diameter measuring device of the gear grinding apparatus according to the embodiment of the present invention, and FIG. 4A is a diagram illustrating a state in which the outer diameter measuring device does not measure the outer diameter of the workpiece. 4 (b) is a diagram showing a state in which the outer diameter measuring instrument measures the outer diameter of the workpiece. FIG. 5 is a partially enlarged side view of a work holding unit and an outer diameter measuring device of a gear grinding apparatus according to an embodiment of the present invention, and FIG. 5A is a diagram illustrating a state in which the outer diameter measuring device measures the outer diameter of a work arbor; FIG. 5B is a diagram showing a state in which the outer diameter measuring instrument measures the outer diameter of the workpiece. It is a flowchart of the master work measurement process which the gear grinding apparatus by embodiment of this invention performs. It is a flowchart of the cutting amount correction | amendment process which the gear grinding apparatus by embodiment of this invention performs.

Hereinafter, a gear grinding apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, the configuration of a gear grinding apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a gear grinding apparatus according to an embodiment of the present invention. FIG. 2 is a side view of a gear grinding apparatus according to an embodiment of the present invention. FIG. 3 is a plan view of a gear grinding apparatus according to an embodiment of the present invention.

  As shown in FIGS. 1 to 3, the gear grinding device 1 has a bed 2 installed on the floor surface. This bed 2 has a substantially rectangular parallelepiped outer shape. In the following description, the longitudinal direction on the upper surface of the bed 2 is referred to as the x-axis direction, the short direction is referred to as the y-axis direction, and the direction orthogonal to the upper surface of the bed 2 is referred to as the z-axis direction.

On the upper surface of the bed 2, there is provided a work holding portion 6 for holding a cycloid gear 4 (hereinafter referred to as “work”) which is a gear to be processed.
The work holding unit 6 has a cylindrical table 8 attached to the upper surface of the bed 2. The table 8 is arranged so that its cylindrical central axis extends along the z-axis direction.
Further, the work holding unit 6 has a cylindrical work machining rotary shaft 10 inserted through the inner periphery of the table 8. The work machining rotary shaft 10 is supported by a bearing provided on the inner periphery of the table 8, and is rotatable about an axis C1 extending in the z-axis direction.

Furthermore, the workpiece holding unit 6 is a workpiece swiveling device for moving the workpiece 4 between a workpiece exchange position for attaching the unmachined workpiece 4 to the workpiece holding unit 6 and a workpiece machining position for machining the workpiece 4. Twelve.
The work turning device 12 includes a prismatic fixing portion 14 fixed to the upper surface of the bed 2 and a prismatic rotating portion 16 rotatably supported by the fixing portion 14.
The rotating part 16 is rotatable around an axis C2 extending in the z-axis direction. A pair of tailstocks 18 are provided on the side surface of the rotating unit 16. The pair of tailstocks 18 are disposed at positions symmetrical with respect to the axis C2. Further, the tail stock 18 is supported on the side surface of the rotating portion 16 so as to be slidable in the z-axis direction.
A work arbor 20 for supporting and rotating the work 4 is attached to each tail stock 18. The work arbor 20 has a round bar shape, and extends downward from the lower end of the tailstock 18 along the z-axis direction. The work arbor 20 is supported by a bearing provided inside the tailstock 18 so as to be rotatable about the longitudinal axis C3 of the work arbor 20.
The workpiece 4 is held at the tip portion of the workpiece arbor 20. At the workpiece machining position, the axis C3 of the work arbor 20 of any tailstock 18 matches the axis C1 of the workpiece machining rotary shaft 10, and the tip portion of the workpiece arbor 20 and the tip portion of the workpiece machining rotary shaft 10 The workpiece 4 is clamped. Thus, when the work arbor 20 of one tail stock 18 is in the workpiece machining position, the work arbor 20 of the other tail stock 18 is in the workpiece replacement position. In addition, the outer peripheral surface of the tip portion of the work arbor 20 is polished and becomes a measurement reference surface that serves as a reference when measuring the outer diameter of the work 4.

A grindstone holding part 22 for holding the grindstone is provided at a position facing the work holding part 6 on the upper surface of the bed 2.
The grindstone holding unit 22 includes a prismatic column 24 provided at a position facing the work holding unit 6 on the upper surface of the bed 2. The column 24 is installed so as to be movable on the upper surface of the bed 2 along the x-axis direction.
A saddle 26 is provided on each side surface of the column 24 facing the work holding unit 6. The saddle 26 is attached to the side surface of the column 24 so as to be slidable in the z-axis direction and rotatable about an axis C4 extending in the x-axis direction.
The saddle 26 is provided with a grindstone head 28 for supporting and rotating the grindstone. The grindstone head 28 is supported on the side surface of the saddle 26 so as to be slidable along an axis C5 orthogonal to the x-axis. Further, the grindstone head 28 includes a grindstone rotating shaft 30 extending along the axis C5. The grindstone rotating shaft 30 is rotated about the axis C5 by the power of a motor provided in the grindstone head 28. A cylindrical grindstone 32 having a helical thread formed on the outer peripheral surface is detachably attached to the tip of the grindstone rotating shaft 30. In a state where the grindstone 32 is attached to the grindstone rotation shaft 30 of the grindstone head 28, the rotation axis of the grindstone 32 coincides with the axis C5.

An outer diameter measuring device 34 for measuring the outer diameter of the work 4 is provided on the upper surface of the grindstone head 28.
Furthermore, the gear grinding apparatus 1 has a control unit that controls the workpiece holding unit 6 and the grindstone holding unit 22. This control unit is electrically connected to the workpiece machining rotary shaft 10, the workpiece turning device 12, the tail stock 18, the column 24, the saddle 26, and the grindstone head 28. The grinding of the workpiece 4 by the grindstone 32 is controlled on the basis of the outer diameter of the workpiece 4 output from.

  Next, the configuration of the outer diameter measuring instrument 34 according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5.

FIG. 4 is a partially enlarged plan view of the work holding unit 6 and the outer diameter measuring device 34 of the gear grinding apparatus 1 according to the embodiment of the present invention.
As shown in FIG. 4, the outer diameter measuring instrument 34 includes a cylinder 36 fixed to the upper surface of the grindstone head 28, a piston rod 38 that moves linearly along the longitudinal direction of the cylinder 36, and a piston via a bracket 40. And a probe 42 attached to the tip of the rod 38. The cylinder 36 is arranged such that its longitudinal axis forms an angle of 55 ° with respect to the axis C5 in a plane parallel to the x-axis and the axis C5 (that is, the rotation axis of the grindstone 32).

When the outer diameter of the workpiece 4 is not measured by the outer diameter measuring instrument 34, as shown in FIG. 4A, the piston rod 38 is housed in the cylinder 36, and the tip of the measuring element 42 is placed on the workpiece 4 or the workpiece. The arbor 20 is not touched.
On the other hand, when the outer diameter of the workpiece 4 is measured by the outer diameter measuring device 34, the piston rod 38 is in a measurement state protruding from the cylinder 36, as shown in FIG. In this measurement state, by moving the column 24, the saddle 26, and the grindstone head 28, the measuring element 42 is moved toward the workpiece 4, and the tip of the measuring element 42 is measured (in FIG. 4B). Touch the workpiece 4). At this time, the positions of the column 24, the saddle 26, and the grindstone head 28 are positioned so that the central axis of the workpiece 4 is positioned on the axis C6 that passes through the tip of the measuring element 42 and is parallel to the longitudinal direction of the cylinder 36. Adjusted.
As described above, in a state where the tip of the measuring element 42 is in contact with the measurement object, the outer diameter measuring device 34 indicates a signal indicating the position of the leading end of the measuring element 42 (specifically, the measuring element 42 on the axis C6). The amount of retreat from the reference position) is output to the control unit.

FIG. 5 is a partially enlarged side view of the work holding unit 6 and the outer diameter measuring device 34 of the gear grinding apparatus 1 according to the embodiment of the present invention. FIG. 5 (a) shows the outer diameter measuring device 34 outside the work arbor 20. The figure which shows the state which measures a diameter, FIG.5 (b) is a figure which shows the state in which the outer diameter measuring device 34 measures the outer diameter of the workpiece | work 4. FIG.
Here, as shown in FIG. 5, the work 4 is sandwiched from both end faces by two disc-shaped preset jigs 44. The tip portion of the work machining rotary shaft 10 supports the preset jig 44 on the lower surface side of the workpiece 4 from below, and the tip portion of the workpiece arbor 20 holds the preset jig 44 on the upper surface side of the workpiece 4 from above. As a result, the workpiece 4 is held via the preset jig 44.

  As shown in FIG. 5, when measuring with the outer diameter measuring instrument 34, the saddle 26 is moved along the z-axis direction to measure the height position of the probe 42 (position in the z-axis direction) and the measurement. Match the height position of the target. That is, when the outer diameter of the work arbor 20 is measured by the outer diameter measuring instrument 34, as shown in FIG. 5A, the height position of the measuring element 42 and the measurement reference surface 46 on the outer periphery of the work arbor 20 are measured. Match the height position. Further, when the outer diameter of the workpiece 4 is measured by the outer diameter measuring device 34, the height position of the measuring element 42 and the height position of the workpiece 4 are matched as shown in FIG. In this way, in the state where the height position of the measuring element 42 and the height position of the measuring object coincide with each other, the tip of the measuring element 42 is brought into contact with the measuring object as shown in FIG. The position of the tip of the child 42 is detected.

Next, a basic flow of grinding performed by the gear grinding apparatus 1 according to the embodiment of the present invention will be described.
When grinding the workpiece 4 by the gear grinding apparatus 1 according to the embodiment of the present invention, first, the workpiece 4 to which the preset jig 44 is attached is fixed to the tip portion of the workpiece arbor 20 of the tail stock 18 at the workpiece replacement position. To do.
Next, the control unit raises the tail stock 18 at the workpiece replacement position, and moves the rotating unit 16 of the workpiece turning device 12 with respect to the axis C2 until the workpiece arbor 20 holding the workpiece 4 is positioned at the workpiece machining position. Rotate.
Next, the control unit lowers the tail stock 18 located at the workpiece machining position, and places the workpiece 4 held by the workpiece arbor 20 on the workpiece machining rotary shaft 10. At this time, the control unit rotates the workpiece arbor 20 and the workpiece machining rotary shaft 10 at the same machining rotation speed. As a result, the workpiece 4 is held by the workpiece machining shaft 10 and the workpiece arbor 20 via the preset jig 44 and rotates at the machining rotation speed.
Next, the control unit drives the column 24, the saddle 26, the grindstone head 28, and the main shaft to engage the workpiece 4 at the workpiece processing position while rotating the grindstone 32. The column 24 is advanced toward the workpiece 4 in the x-axis direction, and the grindstone 32 is cut into the workpiece 4 to finish the outer periphery of the workpiece 4 to a predetermined dimension. At this time, based on the outer diameter of the workpiece 4 measured by the outer diameter measuring device 34, the control unit corrects the cutting amount of the grindstone 32 with respect to the workpiece 4 input in advance as a machining condition, and corresponds to the corrected cutting amount. The column 24 is moved by the moving amount.

  Next, with reference to FIG. 6 and FIG. 7, each process performed by the gear grinding apparatus 1 according to the embodiment of the present invention regarding grinding is described.

FIG. 6 is a flowchart of a master workpiece measurement process performed by the gear grinding apparatus 1 according to the embodiment of the present invention. This master work measurement process is a process for measuring the outer diameter of the master work that serves as a reference for the outer diameter of the work 4. The master workpiece is formed with an outer diameter dimension that is a target for grinding the workpiece 4.
The master workpiece measurement process is performed when an instruction to execute the master workpiece measurement process is given in a state where the master workpiece is held by the workpiece machining rotary shaft 10 and the workpiece arbor 20 via the preset jig 44 at the workpiece machining position. Executed.

  As shown in FIG. 6, when the master workpiece measurement process is started, in step S1, the control unit rotates the workpiece arbor 20 and the workpiece machining rotary shaft 10 at the measurement rotation speed, and the master workpiece is measured. Rotate at rotation speed.

  Next, in step S2, the control unit shifts the outer diameter measuring instrument 34 to the measurement state. That is, the control unit projects the piston rod 38 of the outer diameter measuring instrument 34 from the cylinder 36 so that the measuring element 42 can perform measurement.

  Next, in step S <b> 3, the control unit drives the column 24, the saddle 26, and the grindstone head 28 to measure the outer diameter of the measurement reference surface 46 on the outer periphery of the work arbor 20. The measurement reference plane measurement coordinates (x1, y1, z1) are moved. The measurement reference surface measurement coordinates are such that when the gear grinding apparatus 1 is assembled with ideal dimensions, the tip of the measuring element 42 contacts the measurement reference surface 46 at the reference position (that is, the output of the outer diameter measuring device 34). Position coordinates are set in advance such that the value becomes 0).

Next, in step S <b> 4, the control unit obtains the outer diameter maximum value Amax and the deflection amount r of the measurement reference surface 46 on the outer periphery of the work arbor 20 using the outer diameter measuring device 34.
Specifically, the control unit rotates the work arbor 20 once in a state where the tip of the measuring element 42 is in contact with the measurement reference surface 46 in step S3, and acquires a signal indicating the tip position of the measuring element 42. The control unit acquires the maximum value of the acquired signal (that is, the amount of retreat when the measuring element 42 has retreated most from the reference position) as the outer diameter maximum value Amax of the measurement reference surface 46. Further, the control unit acquires the difference between the maximum value and the minimum value of the acquired signal as the shake amount r.

Next, in step S <b> 5, the control unit calculates an outer diameter _value A ₀ = Amax−r / 2 corresponding to the outer diameter of the measurement reference surface 46 on the outer periphery of the work arbor 20. That is, the control unit subtracts one half of the deflection amount r of the work arbor 20 from the maximum outer diameter value Amax of the measurement reference surface 46, thereby removing the outer diameter value A ₀ excluding the influence of the deflection of the work arbor 20. Is calculated.

  Next, in step S <b> 6, the control unit drives the column 24, the saddle 26, and the grindstone head 28, so that the grindstone head 28 measures the workpiece 4 and master workpiece outer coordinates (see FIG. Move to x2, y2, z2). The workpiece measurement coordinates are such that when the gear grinding device 1 and the workpiece 4 or the master workpiece are manufactured with ideal dimensions, the tip of the measuring element 42 is on the outer periphery of the workpiece 4 or the master workpiece at the reference position. Position coordinates are set in advance so that they come into contact (that is, the output value of the outer diameter measuring device 34 becomes 0).

Next, in step S <b> 7, the control unit obtains the maximum outer diameter B ₀ of the master work by using the outer diameter measuring device 34.
Specifically, the control unit rotates the work arbor 20 once in a state where the tip of the measuring element 42 is brought into contact with the outer periphery of the master work in step S <b> 6, and acquires a signal indicating the tip position of the measuring element 42. The control unit acquires the maximum value of the acquired signal (that is, the retraction amount when the measuring element 42 has retreated most from the reference position) as the outer diameter maximum value B ₀ of the master work.

Next, in step S8, the control unit calculates a workpiece outer diameter reference value C ₀ = B ₀ −A ₀ corresponding to the outer diameter of the master workpiece and stores it in the memory. The outer diameter value A ₀ of the measurement reference surface 46 reflects a change in the distance between the grindstone head 28 and the work arbor 20 due to mechanical thermal displacement of the gear grinding device 1. On the other hand, the maximum outer diameter B ₀ of the master workpiece includes the outer diameter of the master workpiece and the change in the distance between the grinding wheel head 28 and the master workpiece due to the mechanical thermal displacement of the gear grinding device 1 (that is, the grinding wheel head 28 and (Distance change with the work arbor 20) is reflected. That is, the control unit, by subtracting the outer diameter value A ₀ of the measurement reference surface 46 from the outer diameter the maximum value B ₀ of the master work, excluding the effect of the mechanical thermal displacement gear grinding apparatus 1, the outside of the master work A workpiece outer diameter reference value C ₀ reflecting only the diameter is calculated.

Next, in step S9, the control unit drives the column 24, the saddle 26, and the grindstone head 28 to return the grindstone head 28 to the origin, and the piston rod 38 of the outer diameter measuring device 34 is moved to the cylinder 36. Store inside.
After the process of step S9, the control unit ends the master work measurement process.

  FIG. 7 is a flowchart of a cutting amount correction process performed by the gear grinding apparatus 1 according to the embodiment of the present invention. In the cutting amount correction processing, after the master workpiece measurement processing is executed, the workpiece 4 is held by the workpiece machining rotary shaft 10 and the workpiece arbor 20 via the preset jig 44 at the workpiece machining position. This is executed when the start of grinding is instructed. The control unit executes the cutting amount correction process in parallel with the grinding process of the workpiece 4 or by interrupting the grinding process as necessary.

As shown in FIG. 7, when the cutting amount correction process is started, in step S <b> 11, the control unit determines whether or not the process in the grinding process is a stage for correcting the cutting amount of the grindstone 32. The control part of this embodiment determines that it is the stage which correct | amends the cutting amount of the grindstone 32, when 6 processes before final finishing are complete | finished among all 8 processes of the grinding process of the workpiece | work 4. FIG.
If the six steps before final finishing are not completed, the control unit repeats step S11 and waits until the six steps before final finishing are completed.

  If it is determined in step S11 that the process in the grinding process is a stage in which the cutting amount of the grindstone 32 is corrected, the process proceeds to step S12, and the control unit moves the workpiece arbor 20 and the workpiece machining rotary shaft 10 to the measurement rotation speed. And the work 4 is rotated at the rotational speed for measurement.

  Next, in step S13, the control unit shifts the outer diameter measuring instrument 34 to the measurement state. That is, the control unit projects the piston rod 38 of the outer diameter measuring instrument 34 from the cylinder 36 so that the measuring element 42 can perform measurement.

  Next, in step S <b> 14, the control unit drives the column 24, the saddle 26, and the grindstone head 28 to measure the outer diameter of the measurement reference surface 46 on the outer periphery of the work arbor 20. The measurement reference plane measurement coordinates (x1, y1, z1) are moved.

  Next, in step S <b> 15, the control unit uses the outer diameter measuring device 34 to obtain the outer diameter maximum value Amax and the deflection amount r of the measurement reference surface 46 on the outer periphery of the work arbor 20.

Next, in step S <b> 16, the control unit calculates an outer diameter value A ₁ = Amax−r / 2 corresponding to the outer diameter of the measurement reference surface 46 on the outer periphery of the work arbor 20.

  Next, in step S <b> 17, the control unit drives the column 24, the saddle 26, and the grindstone head 28 to move the grindstone head 28 to the workpiece measurement coordinates (x2, y2, z2).

Next, in step S <b> 18, the control unit obtains the outer diameter maximum value B ₁ of the workpiece 4 using the outer diameter measuring device 34.
Specifically, the control unit rotates the work arbor 20 once in a state where the tip of the measuring element 42 is brought into contact with the outer periphery of the master work in step S <b> 17, and acquires a signal indicating the tip position of the measuring element 42. The control unit acquires the maximum value of the acquired signal (that is, the retraction amount when the measuring element 42 has retreated most from the reference position) as the maximum outer diameter B ₁ of the workpiece 4.

Next, in step S19, the control unit has an outer diameter of the maximum value B ₁ of the work 4 acquired in step S18 is, whether less than (0.2 mm in this embodiment) allowable value measured by the outer diameter measuring device 34 Determine.
As a result, when the outer diameter maximum value B _{1 of} the workpiece 4 is not less than the allowable measurement value by the outer diameter measuring instrument 34 (is greater than or equal to the allowable measurement value), the outer diameter measuring instrument 34 determines the outer diameter maximum value B of the workpiece 4. ₁ may not be measured correctly. Therefore, the process proceeds to step S20, the control unit outputs an error indicating outside diameter maximum B ₁ of the work 4 is the allowable measurement concludes the depth of cut correction.

On the other hand, when the outer diameter maximum value B _{1 of} the workpiece 4 is less than the allowable measurement value by the outer diameter measuring device 34, the process proceeds to step S 21, and the control unit moves the workpiece outer diameter value C ₁ corresponding to the outer diameter of the workpiece 4. = B ₁ −A ₁ is calculated. A change in the distance between the grindstone head 28 and the work arbor 20 due to the mechanical thermal displacement of the gear grinding device 1 is reflected in the outer diameter value A ₁ of the measurement reference surface 46. On the other hand, the maximum outer diameter B ₁ of the workpiece 4 includes the outer diameter of the workpiece 4 during grinding and the change in the distance between the grindstone head 28 and the workpiece 4 due to the mechanical thermal displacement of the gear grinding apparatus 1 (that is, The change in the distance between the grinding wheel head 28 and the work arbor 20) is reflected. That is, the control unit, by subtracting the outer diameter value A ₁ of the measurement reference surface 46 from the outer diameter maximum B ₁ of the workpiece 4, to exclude the influence of the mechanical thermal displacement gear grinding apparatus 1, the outside of the workpiece 4 A workpiece outer diameter value C ₁ reflecting only the diameter is calculated.

Next, in step S22, the control unit calculates a correction value Δ ₁ = C ₁ −C ₀ of the cutting amount of the grindstone 32. Work outside diameter value C ₁ is to exclude the influence of the mechanical thermal displacement gear grinding apparatus 1 is a value that reflects only the outer diameter of the workpiece 4, the workpiece outer diameter reference value C ₀ is the mechanical gear grinding apparatus 1 It is a value that reflects only the outer diameter of the master work, excluding the influence of thermal displacement. That is, the outer diameter of the control unit, by subtracting the workpiece outer diameter reference value C ₀ from the work outside diameter value C _1, without being affected by the mechanical thermal displacement gear grinding apparatus 1, a master workpiece and the workpiece 4 Is calculated as a correction value Δ ₁ for the cutting amount of the grindstone 32.

Next, in step S23, the control unit, the correction value delta ₁ calculated in step S22 determines whether or not less than (0.2 mm in this embodiment) the allowable correction value.
As a result, when the correction value Δ ₁ is not less than the allowable correction value (is equal to or greater than the allowable correction value), there is a possibility that the cutting amount of the grindstone 32 cannot be corrected in the subsequent grinding process. Therefore, the process proceeds to step S24, the control unit outputs an error indicating that the correction value delta ₁ is permissible correction value or more, and terminates the depth of cut correction.

On the other hand, when the correction value Δ ₁ is less than the allowable correction value, the process proceeds to step S25, and the control unit reflects the correction value Δ ₁ in the cutting amount of the grindstone 32 in the subsequent grinding process. Specifically, the control unit corrects the cutting amount of the grindstone 32 in each step so that the total value of the cutting amounts of the grindstone 32 in the subsequent grinding process becomes the correction value Δ ₁ .

  Next, in step S26, the control unit drives the column 24, the saddle 26, and the grindstone head 28 to return the grindstone head 28 to the origin, and the piston rod 38 of the outer diameter measuring device 34 is moved to the cylinder 36. Store inside.

  Next, in step S27, the control unit resumes grinding of the workpiece 4 and ends the cutting amount correction process.

  Next, the effect by the gear grinding apparatus 1 of this embodiment mentioned above is demonstrated.

First, the outer diameter measuring instrument 34 measures the outer diameter of the workpiece 4 by bringing the probe 42 supported by the grindstone head 28 into contact with the outer periphery of the workpiece 4 and detecting the position of the probe 42 at the time of contact. Then, the control unit corrects the cutting amount of the grindstone 32 with respect to the workpiece 4 based on the outer diameter of the workpiece 4 measured by the outer diameter measuring device 34.
That is, the outer diameter measuring device 34 directly measures the outer diameter of the workpiece 4, and based on the measurement result, the control unit corrects the cutting amount of the grindstone 32 with respect to the workpiece 4, so that due to disturbance factors such as mechanical thermal displacement, Even if an error occurs in the outer diameter of the workpiece 4 with respect to the target dimension, the cutting amount of the grindstone 32 can be corrected according to the measurement result of the outer diameter of the workpiece 4 reflecting the error. Therefore, the outer periphery of the cycloid gear that is the workpiece 4 can be ground with high accuracy in consideration of disturbance factors such as mechanical thermal displacement.

In particular, the outer diameter measuring device 34 measures the outer diameter of the master workpiece held by the workpiece holding unit 6, and the control unit measures the outer diameter of the master workpiece measured by the outer diameter measuring device 34 and the outer diameter of the workpiece 4. And the cutting amount of the grindstone 32 with respect to the workpiece 4 is corrected based on this difference.
That is, the control unit corrects the cutting amount of the grindstone 32 with respect to the workpiece 4 based on the difference between the outer diameter of the master workpiece and the outer diameter of the workpiece 4 measured by the outer diameter measuring device 34 under common conditions. Therefore, the cutting depth of the grindstone 32 can be corrected by accurately reflecting the error of the outer diameter of the workpiece 4 with respect to the above. Therefore, the outer periphery of the cycloid gear that is the workpiece 4 can be ground with higher accuracy.

Further, the outer diameter measuring device 34 has a position of the measuring element 42 when the measuring element 42 is brought into contact with the outer circumference of the measurement reference surface 46 of the work arbor 20 and a position when the measuring element 42 is brought into contact with the outer circumference of the workpiece 4. Based on the position of the probe 42, the outer diameter of the workpiece 4 is measured.
That is, the position of the measuring element 42 when the measuring element 42 is brought into contact with the outer periphery of the main shaft reflects a change in the distance between the grindstone holding portion 22 and the main shaft, and the measuring element 42 is brought into contact with the outer periphery of the cycloid gear. Since the outer diameter of the cycloid gear is reflected in addition to the change in the distance between the grindstone holding portion 22 and the main shaft, the outer diameter measuring portion is connected to the grindstone holding portion 22 and the main shaft. Thus, only the outer diameter of the workpiece 4 can be extracted. Therefore, the outer diameter of the workpiece 4 can be measured more accurately, and the outer periphery of the cycloid gear that is the workpiece 4 can be ground with higher accuracy.

The outer diameter measuring device 34 measures the outer diameter of the work 4 after any one of the plurality of processes included in the grinding process of the work 4 and before the start of the next process. Based on the outer diameter of the workpiece 4 measured by the measuring instrument 34, the cutting depth of the grindstone 32 in the subsequent processes is corrected.
That is, the outer diameter measuring instrument 34 measures the outer diameter of the workpiece 4 that has undergone a part of the process included in the grinding process, and based on the result of the measurement, the control unit cuts the grinding stone 32 in the subsequent and subsequent processes. Therefore, even if an error occurs in the outer diameter of the workpiece 4 with respect to the target dimension due to a disturbance factor during grinding, the next process is performed according to the measurement result of the outer diameter of the workpiece 4 reflecting the error. The cutting amount of the grindstone 32 thereafter can be corrected. Therefore, the outer periphery of the cycloid gear that is the workpiece 4 can be ground with high accuracy in consideration of disturbance factors such as mechanical thermal displacement.

DESCRIPTION OF SYMBOLS 1 Gear grinding apparatus 2 Bed 4 Cycloid gear, workpiece 6 Work holding part 8 Table 10 Work processing rotary shaft 12 Work rotating device 14 Fixed part 16 Rotating part 18 Tailstock 20 Work arbor 22 Grinding wheel holding part 24 Column 26 Saddle 28 Grinding wheel head 30 Grinding wheel rotation shaft 32 Grinding wheel 34 Outer diameter measuring device 36 Cylinder 38 Piston rod 40 Bracket 42 Measuring element 44 Preset jig 46 Measurement reference plane

Claims (4)

In a gear grinding device that grinds a cycloid gear using a rotating grindstone,
A bed installed on the floor;
A gear holder that is supported by the bed and rotatably holds the cycloid gear at the processing position of the cycloid gear;
A grindstone holding unit supported by the bed at a position facing the gear holding unit, holding the grindstone, and moving the grindstone toward the cycloid gear held by the gear holding unit. The whetstone holding part;
By moving the grindstone holding part, the measuring element supported by the grindstone holding part is moved from the grindstone side toward the cycloid gear side and brought into contact with the outer periphery of the cycloid gear. An outer diameter measuring device for measuring the outer diameter of the cycloid gear by detecting the position;
Based on the outer diameter of the cycloid gear measured by the outer diameter measuring device, a controller that corrects the cutting amount of the grindstone with respect to the cycloid gear;
A gear grinding apparatus comprising: In a gear grinding device that grinds a cycloid gear using a rotating grindstone,
A bed installed on the floor;
A gear holder that is supported by the bed and rotatably holds the cycloid gear at the processing position of the cycloid gear;
A grindstone holding unit supported by the bed at a position facing the gear holding unit, holding the grindstone, and moving the grindstone toward the cycloid gear held by the gear holding unit. The whetstone holding part;
An outer diameter measuring instrument that measures the outer diameter of the cycloid gear by contacting the outer circumference of the cycloid gear with the measuring element supported by the grindstone holding unit and detecting the position of the measuring element at the time of the contact;
Based on the outer diameter of the cycloid gear measured by the outer diameter measuring device, a controller that corrects the cutting amount of the grindstone with respect to the cycloid gear;
With
The gear holding unit includes a main shaft that rotates the cycloid gear at the processing position,
The outer diameter measuring device is based on the position of the measuring element when the measuring element is brought into contact with the outer periphery of the main shaft and the position of the measuring element when the measuring element is brought into contact with the outer periphery of the cycloid gear. A gear grinding apparatus for measuring an outer diameter of the cycloid gear. The gear holding portion rotatably holds a master work serving as a reference for the outer diameter of the cycloid gear at the processing position,
The outer diameter measuring instrument measures the outer diameter of the master work held by the gear holding section, and the control section measures the outer diameter of the master work and the cycloid gear measured by the outer diameter measuring instrument. The gear grinding apparatus according to claim 1 or 2 , wherein a difference with an outer diameter is calculated, and a cutting amount of the grindstone with respect to the cycloid gear is corrected based on the difference. The outer diameter measuring device measures the outer diameter of the cycloid gear after the start of the next step after any of the plurality of steps included in the grinding of the cycloid gear,
The said control part correct | amends the cutting amount of the said grindstone in the process after the said next process based on the outer diameter of the said cycloid gear measured by the said outer diameter measuring device in any one of Claims 1 thru | or 3. The gear grinding apparatus as described.

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