JP3918585B2 - Gear and honing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear honing machine.
[0002]
[Prior art]
A gear / honing machine is a device that finishes a workpiece tooth surface by sliding a tooth surface generated by rotating a grinding wheel by meshing a toothed internal grindstone and a workpiece (gear) with an axis crossing angle.
[0003]
One of the conventional gear and honing machines has a driving force only on the side of the internal grindstone, and does not have a driving force on the work. There are gear and honing machines that are polished.
[0004]
FIG. 9 is a schematic view showing a meshing portion between an internal grindstone and a workpiece in such a gear / honing machine.
[0005]
Since the gear / honing machine of the follow-up machining method has a drive source only on the internal grindstone 3 side and the workpiece 2 is configured to follow the internal grindstone 3, the driven side tooth surface 201 of the workpiece 2 is composed of the grindstone 3. Between the drive-side tooth surface 301 of the grindstone 3 and the driven-side tooth surface 201 of the work 2 by the driving force to rotate the work 2 and the friction and inertia of the work shaft (force against the wheel). A pressing force is generated and polished. For this reason, the pressing force on the opposite tooth surface 202 of the driven side tooth surface of the workpiece 2 is weak, and there is a problem that a sufficient amount of polishing cannot be obtained with the opposite tooth surface 202.
[0006]
This similarly occurs in the dressing process for polishing the teeth of the internal grindstone.
[0007]
Toothed internal whetstone dresses are dressed in the same way as during machining by engaging a dressing gear electrodeposited with diamond abrasive grains on a base metal that has a shape approximating the shape of the workpiece and meshing with the internal whetstone. However, in the dressing process, if the pressing force between the tooth surface of the grinding wheel and the tooth surface of the dressing gear (the force against the rotation) is large, not only the opposite tooth surface of the grinding wheel will not be dressed but also the shape of the dressing gear will be accurate. However, it cannot be transferred to the internal whetstone.
[0008]
For this reason, in the gear and honing machine of the swivel processing method, when grinding a workpiece, after rotating the workpiece in one rotation direction, polishing the workpiece, the tooth surface that could not be polished by rotating in the opposite direction is removed. I am going to polish.
[0009]
However, a gear as a workpiece is preferably polished by rotating in the direction in which the gear is actually used, so that polishing by one-way rotation is desired.
[0010]
In addition, when dressing an internal grinding wheel by rotating in two directions when dressing, each tooth of the internal grinding stone is dressed from both sides, so it gradually becomes thinner and the tooth thickness becomes thinner, and the life of the grinding wheel is shortened. Shorter. This also changes the BBD (Between Ball Diameter) of the grindstone. The internal whetstone is usually used in a wide BBD range by changing the amount of dislocation for each dressing, but if the whetstone thickness becomes thin, the whetstone rigidity becomes insufficient and the processing accuracy cannot be satisfied. is there.
[0011]
In order to solve such a problem, various solutions have been conventionally used.
[0012]
First of all, in the gear honing machine by swivel processing, the friction of the spindle is reduced by lowering the pushing force of the tail side spindle to the workpiece to the limit, and the distance between the drive side tooth surface of the grindstone and the driven side tooth surface of the workpiece is reduced. In this way, both the tooth surfaces of the workpiece are polished by machining in one rotation direction so that the pressing force on the surface and the pressing force on the tooth surface opposite to the driven tooth surface of the workpiece are evenly generated.
[0013]
A gear / honing machine that rotates with the internal grindstone and a work source as well as the internal grindstone, and performs polishing while controlling the internal grindstone and the work synchronously. is there.
[0014]
Such a synchronous control type gear / honing machine is an encoder in which an internal grinding wheel is driven by a high-precision gear reducer from an internal grinding wheel drive motor, and rotational position information of the grinding wheel shaft is directly connected to the grinding wheel drive motor. On the other hand, the work axis is directly driven by the servo motor, and the rotation information of the work wheel is taken from the encoder directly connected to the work axis spindle and controlled so that the rotation position of the internal grindstone and the rotation position of the work are synchronized. ing.
[0015]
By driving the internal grindstone and the workpiece with independent drive sources and synchronously controlling them so that their rotational positions coincide with each other, they are pressed between the drive-side tooth surface of the grindstone and the driven-side tooth surface of the workpiece. The force and the pressing force on the tooth surface opposite to the driven tooth surface of the workpiece are made uniform so that both tooth surfaces of the workpiece can be polished by machining in one rotation direction.
[0016]
[Problems to be solved by the invention]
However, the conventional gear honing machine has various problems.
[0017]
First of all, in the gear honing machine with follow-up machining, the pressing force of the tail spindle against the workpiece is lowered to the limit, so when the machining load changes and a load exceeding the weak pushing force of the tail spindle occurs There is a problem that the tail spindle retracts under the cutting load, the posture of the workpiece and the dress gear collapses, and the machining accuracy and the dressing accuracy are extremely deteriorated.
[0018]
On the other hand, in the synchronous control type gear honing machine, the internal grinding wheel and the workpiece are also controlled synchronously with the driving force, so that force is evenly applied to both sides of the workpiece tooth surface regardless of the direction of rotation. Therefore, in principle, both tooth surfaces can be processed in one rotation direction.
[0019]
However, although the grindstone shaft motor and the work shaft (and the work shaft motor) are configured to be electrically synchronized, the power transmission system (reduction gear portion) of the grindstone shaft has backlash due to gears. Due to the structure (backlash of several tens of μm or more), the backlash not only causes an error in the rotational position information of the grindstone, but also causes the wheel's behavior not to be controlled by the grindstone drive motor. .
[0020]
For this reason, the synchronization accuracy between the grindstone and the workpiece cannot be kept at a level of several μm or less, which is equivalent to the required tooth profile accuracy, and the processing accuracy is not improved as expected.
[0021]
In addition, the synchronous control type gear / honing machine has a problem that a phase shift between the grindstone and the work caused by a slight backlash of the grindstone shaft power transmission system creates undulations on the machined work tooth surface. . This also occurs during dressing of the grindstone, and creates undulations on the tooth surface of the dressed internal grindstone.
[0022]
Furthermore, in the synchronous control type gear / honing machine, the servo gain of the workpiece axis motor, which is the tracking side, is increased to just before the limit of oscillation of the motor in order to improve the synchronization accuracy as much as possible. In addition, the servo motor easily oscillates, and in combination with the above-mentioned factors of the grinding wheel shaft power transmission system backlash, there is a problem that fine irregularities are formed on the workpiece tooth surface, and the one that satisfies the required accuracy of the transmission gear cannot be processed. It was.
[0023]
Accordingly, the present invention is to provide a gear / honing machine capable of uniformly polishing both tooth surfaces of a workpiece by rotational machining in one direction.
[0024]
[Means for Solving the Problems]
The present invention is achieved by the following configurations.
[0025]
  (1) A workpiece in which a tooth shape is formed in advance is rotatably held, and the workpiece and the grinding stone are relatively moved while a grinding stone shaped into a shape corresponding to the tooth shape is brought into contact with the teeth of the workpiece. In a gear honing machine that rotates and polishes the workpiece, the first holding means that holds one end of a workpiece shaft to which the workpiece is attached, the other end of the workpiece shaft, and the first holding Second holding means that can be moved back and forth to sandwich the work shaft with the means, and thrust generating means for pressing the second holding means against the other end of the work shaft with a predetermined thrust. And a retraction preventing means for preventing the second holding means from retreating.The reverse preventing means includes a wedge member formed with an inclined surface in contact with a rear portion of the second holding means opposite to the side holding the other end of the work shaft in the second holding means, and the wedge member Elevating means for elevating and lowering the wedge member, and after the predetermined thrust is applied to the second holding means by the thrust generating means, the wedge member is lowered by the elevating means, and the wedge member and the A force obtained from the mass of the lifting / lowering means is applied to contact the rear part of the second holding means.Gear honing machine characterized by this.
[0026]
  (2)The force obtained from the mass of the wedge member and the lifting means when the wedge member is brought into contact with the rear part of the second holding means is larger than the upward force applied to the wedge member by the rear part of the second holding means.It is characterized by that.
[0027]
(3) The thrust generation means generates a thrust enough to rotate the workpiece so that teeth shaped on the grindstone can come into contact with both surfaces of the teeth of the workpiece with equal force. .
[0033]
【The invention's effect】
The present invention has the following effects for each claim.
[0034]
  According to the first aspect of the present invention, the work shaft is provided with thrust preventing means for preventing the second holding means from retreating separately from the thrust generating means for pressing the work shaft in the direction of the first holding means. It can be held by the generating means with a predetermined thrust. On the other hand, when the load during machining increases, the second holding means can be prevented from retreating by the retreat preventing means. For this reason, even when the load is unexpectedly increased, the second holding means does not escape (retreat) and the workpiece posture is not lost, so the change in accuracy due to individual differences in workpieces is reduced, and deterioration in machining accuracy is reduced. can do.Then, a wedge member formed with an inclined surface in contact with the rear portion of the second holding means is provided as a backward prevention means, and the wedge member is moved up and down after a predetermined thrust is applied to the second holding means by the thrust generating means. Since it is lowered by the means and brought into contact with the rear part of the second holding means, the inclined surface of the wedge member always hits the rear part of the second holding means regardless of the position of the second holding means. The means can be prevented from retreating.
[0035]
  According to the present invention as set forth in claim 2,Since the force obtained from the mass of the wedge member and the lifting / lowering means is made larger than the upward force applied to the wedge member by the rear part of the second holding means, the backward movement of the second holding means is surely prevented. can do.
[0036]
According to this invention of Claim 3, a workpiece | work rotates so that the tooth shape | molded by the grindstone can thrust the thrust which hold | suppresses a 2nd holding | maintenance means by a thrust generation means on both surfaces of the tooth | gear of a workpiece | work with equal force. Since the thrust is of a certain degree, both tooth surfaces can be evenly polished without repeating forward and reverse rotations and polishing from both directions.
[0042]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0043]
(First embodiment)
FIG. 1 is a perspective view showing an external configuration of the gear honing machine according to the first embodiment, and FIG. 2 is a schematic diagram for explaining the gear honing machine.
[0044]
The gear honing machine 1 in the first embodiment is a gear honing machine using a follow-up system.
[0045]
The gear honing machine 1 includes a head stock 11 and a tail stock 12 that hold a work shaft 20 (see FIG. 2) to which a work 2 is attached, and a grindstone base unit 13 that includes an internal grindstone 3. A workpiece 2 in which teeth are formed in advance by roughing is rotatably held by a head stock 11 and a tail stock 12, and an internal grindstone 3 in which teeth having a shape corresponding to the completion of the workpiece 2 are shaped is used as the workpiece 2. The workpiece 2 is polished by rotating while pressing, and the gear of the workpiece 2 is finished and shaped.
[0046]
As can be seen from the appearance configuration shown in FIG. 1, both the head stock 11 and the tail stock 12 are installed on a table 16 on a machine bed 15 in the gear honing machine 1.
[0047]
The gear / honing machine 1 includes a C axis that is a rotation axis of a workpiece, an S axis that is a rotation axis of the internal grindstone 3, a Z axis that is a cutting axis of the internal grindstone 3, an X axis that is a work oscillation axis, A Y axis which is a helical angle axis and a swing table axis for tilting the workpiece for crowning are provided.
[0048]
Of each axis, the S-axis motor 19 rotates the internal grindstone 3 for each axis. The Z axis generates a force by pressing the internal grindstone 3 in the direction of the workpiece 2 by a motor (not shown), and the Y axis adjusts the angle of the helical angle of the internal grindstone 3. Further, the X axis is moved by a hydraulic cylinder 17, and the workpiece is held by the hydraulic cylinder 17 with a predetermined force. The swing table axis is an axis that rotates the entire table 16 and is used for setting the crowning for the workpiece.
[0049]
The head stock 11 and the tail stock 12 incorporate a head spindle 21 and a tail spindle 22, respectively. The tips of the head spindle 21 and the tail spindle 22 are both sharp conical shapes, and the center hole of the work shaft 20 is a conical recess having an inclination of about 60 °. In this recess, the head spindle 21 The tail spindles 22 are inserted into the tips of the tail spindles 22 to hold the workpiece shaft 20.
[0050]
Both the head spindle 21 and the tail spindle 22 are rotatably supported by bearings 23 in the head stock 11 and the tail stock 12, and the work 2 is rotated along with the rotation of the internal grindstone 3. ing.
[0051]
The hydraulic cylinder 17 moves the entire tailstock 12 on the X axis. A rail 18 is provided on the table 16, and the tailstock 12 moves on the rail 18.
[0052]
On the table 16, a tail stock support portion 30 that supports the rear portion of the tail stock 12 is further provided.
[0053]
The tail stock support portion 30 includes a wedge member 32 that abuts on a slope 31 formed at the rear portion of the tail stock 12, a hydraulic cylinder 33 that raises and lowers the wedge member 32, and a column 34 that supports the hydraulic cylinder 33. The rail 34 is provided on the column 34, and the wedge member 32 moves up and down along the rail 35.
[0054]
The operation of the gear honing machine in the first embodiment configured as described above will be described.
[0055]
In polishing the workpiece 2, the workpiece 2 is attached by moving the tailstock 12 forward and backward.
[0056]
At this time, the wedge member 32 of the tail stock support 30 is retracted upward so as not to contact the rear slope 31 of the tail stock 12.
[0057]
In this state, the tail stock 12 is moved by the hydraulic cylinder 17 to hold the work 2 together with the work shaft 20.
[0058]
The pressing force (thrust) by the hydraulic cylinder 17 is a small thrust such that the workpiece 2 does not drop and the rotational friction between the head spindle 21 and the tail spindle 22 generated by the thrust of the tail stock 12 does not affect the machining accuracy. It sets so that it may become several hundred N or less.
[0059]
Thus, the thrust by the small hydraulic cylinder 17 enables the workpiece 2 to polish not only the tooth surface in the rotation direction but also the tooth surface on the opposite side.
[0060]
After the positioning of the tail stock 12 by the hydraulic cylinder 17 is completed, the wedge member 32 of the tail stock support 30 is moved downward and brought into contact with the rear slope 31 of the tail stock 12.
[0061]
After the workpiece 2 is set in this way, the polishing process of the workpiece 2 is started.
[0062]
During the polishing process, the cutting force of the internal grindstone 3 is applied to the workpiece 2 in the Z-axis direction.
[0063]
The force in the Z-axis direction applied to the workpiece 2 is received by the head stock 11 and the tail stock 12. This force is a force for retracting the tail spindle 22 (the headstock 11 is fixed). In the first embodiment, the tailstock 12 is supported by the tailstock support 30 in the rear portion. Therefore, a force for retreating the tailstock 12 is received by the tailstock support portion 30 to prevent the tailstock 12 from retreating.
[0064]
By making the rear part of the tail stock 12 into a slope, the wedge member 32 can be placed on the rear slope of the tail stock 12 even when the position of the tail stock 12 changes depending on the length of the work or the chamfering amount of the center hole of the work shaft 20. It can be made to adhere to 31 without a gap.
[0065]
In addition, it is preferable that the wedge member 32 can be inserted / removed in a 90 ° direction from the moving direction of the tailstock 12.
[0066]
Here, conditions for preventing the tailstock 12 from retreating will be described. FIG. 3 is a drawing schematically showing the tail stock 12 and the wedge member 32 in order to explain conditions for preventing the tail stock 12 from retreating.
[0067]
The angles of the slopes of the tailstock rear slope 31 and the wedge member 32 are the same. The slope angle of the wedge member 32 shown in FIG. 3 is θ, the static friction force on this slope is Ff, and the force received by the tailstock 12 is F Then, the force Fs acting on the slope is Fs = Fsinθ−Ff.
[0068]
  Since the static friction force Ff = μM sin θ (where μ is a friction coefficient), the upward force Fa acting on the wedge member 32 is expressed by the following equation (1). It should be noted that the mass M means that the hydraulic cylinder 33 is free, M = the mass of the wedge member 32 + the lock of the cylinder 33.DoPart mass.
[0069]
Fa = (Fsinθ−μMsinθ) cosθ
= (F-μM) sin θ cos θ (1)
In order to prevent the tailstock 12 from retreating, it is sufficient that Fa is always smaller than the downward force Fb applied to the wedge member 32.
[0070]
  Therefore, the downward force Fb applied to the wedge member 32 causes the mass of the wedge member 32 and the lock of the cylinder 33 to be locked while the hydraulic cylinder 33 is free.DoIt can be obtained by applying the gravitational acceleration g to the mass M obtained by adding the mass of the part. That is, the downward force Fb applied to the wedge member 32 is Fb = Mg.
[0071]
Therefore, in order to prevent the tailstock 12 from moving backward, since Fa <Fb, the slope angle θ and the slope friction coefficient μ may be set so as to satisfy the following expression (3).
[0072]
(F−μM) sin θ cos θ <Mg (3)
As described above, according to the first embodiment, at the time of clamping, it is possible to freely adjust the forward / backward position of the tailstock 12 by the hydraulic cylinder 17 to clamp the workpiece 2, and at the time of workpiece clamping In this case, the force with which the tail stock 12 presses the workpiece 2 can be minimized so that the processing accuracy due to the rotational friction between the head spindle 21 and the tail spindle 22 does not deteriorate. Even if a large machining load is momentarily generated due to poor pre-machining accuracy of the workpiece 2 or the like by making contact so as to be in close contact, the tail stock support unit 30 always receives the force that the tail stock 12 tries to move backward. Processing can be continued without changing the posture of the workpiece 2
[0073]
Further, according to the first embodiment, the workpiece shaft 20 to which the dressing teeth as the workpiece are attached can be held with little friction even when dressing the internal grindstone 3, so Since the wheel teeth can be dressed with this rotation, the wear of the tooth thickness of the internal grinding wheel is reduced compared to the conventional forward and reverse bidirectional processing, and the life of the grinding wheel can be extended. The change in BBD (Between Ball Diameter) of the grindstone can be reduced.
[0074]
In the first embodiment, the slope 31 is formed at the rear portion of the tail stock 12, but the rear portion of the tail stock 12 is not necessarily such a slope, and is in contact with the wedge member 32. The tail spindle 22 can be prevented from retreating in any shape that can satisfy the condition of the above expression (3).
[0075]
(Second Embodiment)
FIG. 4 is a perspective view showing an external configuration of the gear honing machine according to the second embodiment, and FIG. 5 is a schematic diagram for explaining the gear honing machine.
[0076]
The gear and honing machine 51 in the second embodiment is a gear and honing machine that independently drives the internal grindstone 3 and the workpiece 2 (see FIG. 5).
[0077]
The gear and honing machine 51 has the same basic configuration as that of the first embodiment described above. The head stock 11 and tail stock 12 holding the work shaft 20 (see FIG. 5) to which the work 2 is attached, A grinding wheel base unit 13 including a null grinding wheel 3 is provided, and a C-axis motor 52 for rotating the workpiece 2 is further provided.
[0078]
The gear / honing machine 1 includes a C axis that is a rotation axis of a workpiece, an S axis that is a rotation axis of the internal grindstone 3, a Z axis that is a cutting axis of the internal grindstone 3, an X axis that is a work oscillation axis, A Y axis which is a helical angle axis and a swing table axis for tilting the workpiece for crowning are provided.
[0079]
Of each axis, the S-axis motor 19 rotates the internal grindstone 3 for each axis. The Z axis generates a force by pressing the internal grindstone 3 in the tooth surface direction of the workpiece by a motor (not shown), and the Y axis adjusts the angle of the helical angle of the internal grindstone 3. Further, the X axis is moved by a hydraulic cylinder 17, and the workpiece is held by the hydraulic cylinder 17 with a predetermined force. The swing table axis is an axis that rotates the entire table 16 and is used for setting the crowning for the workpiece.
[0080]
In the gear honing machine 51, the headstock 11 and the tailstock 12 are both fixed to the table 16 on the machine bed 15.
[0081]
The head stock 11 and the tail stock 12 incorporate a head spindle 21 and a tail spindle 22, respectively.
[0082]
Both the head spindle 21 and the tail spindle 22 are rotatably supported by bearings 23 in the head stock 11 and the tail stock 12.
[0083]
The rear end of the head spindle 21 is connected to a C-axis motor 52, and the work 2 held by the head spindle 21 and the tail spindle 22 together with the head stock 11 is rotated by the rotation of the C-axis motor 52.
[0084]
The rear end of the head spindle 21 and the C-axis motor 52 are directly connected by a coupling device 54, and an encoder 53 for measuring the rotational position of the head spindle 21 is attached to the rotating shaft of the C-axis motor 52. ing.
[0085]
The C-axis motor 52 is a servo motor that can arbitrarily change the torque by controlling the supplied current.
[0086]
Further, a chuck 55 is attached to the tip of the head spindle 21 on the workpiece side. The workpiece shaft 20 is sandwiched by the chuck 55 so that the workpiece 2 can be reliably rotated.
[0087]
The tip of the tail spindle 22 has a sharp conical shape, and the center hole of the workpiece shaft 20 is a conical recess having an inclination of about 60 °. The tip of the tail spindle 22 enters the recess and the workpiece shaft. One of 20 is held.
[0088]
The hydraulic cylinder 17 moves the tail spindle 22 on the X axis on the tail stock 12. The tail spindle 22 is housed in a case 24 so as to be rotatable, and the case 24 moves along a rail 25 provided on the tail stock 12.
[0089]
The S-axis motor 19 has an encoder 29 attached to its rotating shaft, and measures the rotational position of the S-axis. For the connection between the S-axis motor 19 and the internal grindstone 3, it is preferable to use a silent chain (not shown) having almost no backlash.
[0090]
The operation of the gear honing machine in the second embodiment configured as above will be described.
[0091]
Hereinafter, in the second embodiment, three control modes will be described as control modes of the S-axis motor 19 and the C-axis motor 52 that are driving sources for rotating the internal grindstone 3 and the workpiece 2.
[0092]
(First control mode)
FIG. 6 is a block diagram of a control system for explaining the first control mode.
[0093]
In the first control mode, the C-axis motor 52 is controlled to have a predetermined torque.
[0094]
For this reason, in the first control mode, as shown in FIG. 6, as the control device, a current detector 61 for detecting the current value supplied to the current control type C-axis motor 52, and a current detector A comparator 62 that compares the current value detected by 61 with the input current command value; and a current controller 62 that controls the current supplied to the C-axis motor 52 from the comparison result by the comparator 62.
[0095]
The current command value is set in advance so as to obtain an appropriate amount of polishing between the workpiece 2 and the internal grindstone 3, and a workpiece shaft spindle (head spindle & head) generated by the pressing force of the tail spindle 22. A torque that cancels out the friction (rotation resistance) of the tail spindle) is applied in the direction in which the workpiece 2 rotates.
[0096]
According to this first control mode, the gear / honing machine 51 is smoothly rotated with a small backlash by the internal grindstone 3 by a silent chain or the like, while the C-axis for rotating the workpiece 2 is used for the tail spindle 22. Since torque is applied so that the friction of the workpiece spindle caused by the pressing force is offset, the pressing force of the grindstone can be evenly applied to both tooth surfaces of the workpiece, and the grinding amount of both tooth surfaces can be evenly distributed. Can be.
[0097]
In addition, since the workpiece 2 is rotated by torque control in this way, it is possible to apply a large thrust that is not defeated by cutting as a pressing force by the tail spindle 22 for holding the workpiece, and an unexpected cutting load. Even when it increases, the tail stock does not escape (retreat) and the work posture is not lost. Therefore, a higher orthodontic force than in the past can be achieved with high accuracy in a short time.
[0098]
Furthermore, during dressing, the internal grindstone 3 can be dressed without repeating forward and reverse bidirectional processing, so there is less wear on the tooth thickness due to forward and reverse bidirectional processing. The service life can be extended and the change in BBD (Between Ball Diameter) of the grindstone can be reduced.
[0099]
Further, the force required to hold the workpiece axis by the tail stock 12 may be always held with the same large thrust without changing between the workpiece polishing and the dressing. There is no need to switch during dressing.
[0100]
In addition, in the first control mode, since it is not necessary to synchronously control the rotational positions of the S-axis motor 19 and the C-axis motor 52, the configuration of the control device can be simplified.
[0101]
(Second control mode)
FIG. 7 is a block diagram of a control system for explaining the second control mode.
[0102]
In the second control mode, the C-axis motor 52 is controlled to have a predetermined speed, and torque is also controlled so that no large torque fluctuation occurs when the speed is changed in response to the speed fluctuation. It is.
[0103]
Therefore, in the second control mode, as shown in FIG. 7, as the control device, a speed detector 65 that detects the rotation speed of the C-axis motor 52 from the output of the encoder 53, and a detection speed of the speed detector 65. Is supplied to the C-axis motor 52, a comparator 66 that compares the input speed command value and the speed correction amount, a speed controller 67 that outputs a current value so as to be a speed command based on the comparison result of the comparator 66, and Current detector 61 for detecting the current value to be detected, comparator 68 for comparing the current value detected by current detector 61 with the current value output from speed controller 67, and comparison by comparator 68 And a current controller 69 for controlling the current supplied to the C-axis motor 52 from the result.
[0104]
Here, the current controller 69 has a function of limiting the current value output as a comparison result of the comparator 68 so as not to exceed the current value when the current value exceeds a predetermined value.
[0105]
This function is referred to as torque limit. In speed control, a large torque change occurs in the C-axis motor 52 in an attempt to correct this when the speed changes greatly. The amount of contact with the tooth surface of the work 2 changes greatly, causing a temporary fluctuation in the polishing amount and a wavy defect on the tooth surface. In order to prevent this, torque should be prevented so that a large torque fluctuation does not occur. This is a limitation.
[0106]
  The speed command value is a speed at which the work 2 is rotated so that the moving speed of each tooth of the internal grindstone 3 matches the moving speed of each tooth of the work 2. Such a speed command value is obtained, for example, by determining the S-axis rotation speed from the output from the encoder 29 of the S-axis motor 19 and dividing the S-axis rotation speed by the rotation speed ratio between the S-axis motor and the internal grinding wheel. Thus, the rotation speed of the internal grindstone 3 is required.-NalThe moving speed of each tooth of the internal grindstone 3 is obtained from the number of teeth of the grindstone. Then, based on the obtained moving speed of each tooth of the internal grindstone 3 and the number of teeth of the work 2, the rotation of the work 2 is made so that the moving speed of each tooth of the work 2 matches the moving speed of each tooth of the internal grindstone 3. Find the speed.
[0107]
The speed correction amount is used to arbitrarily advance or delay the rotation speed of the work 2 with respect to the rotation speed of the internal grindstone 3. Thereby, the contact condition between the teeth of the workpiece 2 and the teeth of the internal grindstone 3 can be adjusted.
[0108]
Such adjustment of the tooth contact, for example, due to variations in the pre-processing accuracy of the work 2, there are cases where it is better to polish either tooth surface more than both surfaces evenly polished, In such a case, by correcting the speed, it is possible to adjust the polishing amount on both sides in consideration of variations in pre-processing accuracy.
[0109]
According to this second control mode, the gear / honing machine 51 is rotated smoothly with a small backlash by the internal grindstone 3 by a silent chain or the like, while the workpiece 2 has an internal movement speed of each tooth. Since it rotates so that it may correspond to the moving speed of every tooth | gear of the grindstone 3, the pressing force of the grindstone equal to both the tooth surfaces of a workpiece | work can be obtained, and the grinding amount of both tooth surfaces can be equalized.
[0110]
In addition, since the workpiece 2 is rotated by speed control, it becomes possible to apply a large thrust not to be defeated by the pressing force by the tail spindle 22 for holding the workpiece, which is higher than the conventional orthodontic force. It can be achieved with high accuracy in a short time.
[0111]
Furthermore, also in the second control mode, as in the first embodiment, it is possible to apply a large thrust without losing the cutting force to the pressing force by the tail spindle 22 for holding the workpiece. Even when the cutting load is increased, the tail stock does not retreat and the posture of the workpiece does not collapse, and a higher orthodontic force than before can be achieved with high accuracy in a short time. Further, it is not necessary to switch the thrust by the tailstock 12 during workpiece polishing and dressing.
[0112]
Furthermore, in the second control mode, it is not necessary to synchronously control the rotational positions of the S-axis motor 19 and the C-axis motor 52.
[0113]
(Third control mode)
FIG. 8 is a block diagram of a control system for explaining the third control mode.
[0114]
In the third control mode, the position of the C-axis motor 52 is controlled with respect to the S-axis motor, and the torque is greatly changed when the speed is changed in response to the speed fluctuation. The torque is also controlled so as not to occur.
[0115]
Therefore, in the third control mode, as shown in FIG. 8, as the control device, a gain adjuster 71 for adjusting the degree of the position FB signal that is the output from the encoder 53 of the C-axis motor 52, A comparator 72 that compares the output from the gain adjuster 71 with the position command value and the position correction value, a position controller 73 that outputs a speed command so as to be a position command based on the comparison result of the comparator 72, and a C-axis motor A speed detector 65 that detects the rotational speed of the encoder 52 from the output of the encoder 53, a comparator 66 that compares the detected speed of the speed detector 65 and the speed command value output from the position controller 73, and a comparison of the comparator 66 A speed controller 67 that outputs a current value as a speed command based on the result, a current detector 61 for detecting a current value supplied to the C-axis motor 52, and an electric current detected by the current detector 61 It comprises a comparator 68 for comparing the current value output from the value and the speed controller 67, a current controller 69 for controlling the current supplied from the comparison result by the comparator 68 to the C-axis motor 52.
[0116]
Here, the current controller 69 has a function to limit the torque, as in the second embodiment.
[0117]
For the position command value, the amount of movement of the internal grindstone is obtained from the position signal obtained from the encoder output of the S-axis motor 19 driving the internal grindstone 3, and the workpiece 2 is rotated by the same amount of movement. This is a value for instructing a position to be used.
[0118]
The gain adjuster 71 adjusts the synchronization accuracy. Here, the synchronization accuracy with respect to the position command value is lowered. Conventionally, when synchronously controlling the rotational position of the workpiece 2 with respect to the internal grindstone 3, the synchronization accuracy of about several μm is reduced to about several tens of μm by the gain adjuster 71.
[0119]
The specific synchronization accuracy is preferably adjusted to, for example, about 1/10 of the workpiece processing accuracy, more preferably in the range of about 50 μm to 100 μm.
[0120]
As a result, even when the rotational position of the workpiece 2 is shifted relative to the internal grindstone 3, relatively slow alignment control is performed, so that a sudden position change does not occur, and undulations on the workpiece wavefront are prevented. can do.
[0121]
As such a gain adjuster 71, specifically, for example, when a pulse encoder is used as the encoder 53, the number of pulses (which may be a pulse frequency) is usually amplified to increase the synchronization accuracy. However, here, the number of detected pulses is reduced by dividing by a predetermined number, and the current position of the workpiece 2 is set to the position of the internal grindstone obtained from the encoder output of the S-axis motor 19 as described above. Thus, an error of about several tens of μm is created.
[0122]
In addition, when a pulse encoder is used as the encoder 53, instead of the gain adjuster, the encoder 53 having a resolution itself lower than the resolution of the encoder 29 attached to the S-axis is used. The accuracy can also be reduced.
[0123]
The position correction amount is for arbitrarily shifting the rotational position of the workpiece 2 with respect to the rotational position of the internal grindstone 3. Thereby, the contact condition between the teeth of the workpiece 2 and the teeth of the internal grindstone 3 can be adjusted.
[0124]
Such adjustment of the tooth contact, for example, due to variations in the pre-processing accuracy of the work 2, there are cases where it is better to polish either tooth surface more than both surfaces evenly polished, In such a case, by correcting the speed, it is possible to adjust the polishing amount on both sides in consideration of variations in pre-processing accuracy.
[0125]
According to this third control mode, the gear / honing machine 51 is rotated smoothly with a small backlash by a silent chain or the like, while the workpiece 2 is sweetened with respect to the internal grindstone 3. By controlling the position, the phenomenon that the motor vibrates for the synchronous control as in the prior art can be suppressed, and a very smooth rotation control can be performed, and the occurrence of waviness on the tooth surface can be suppressed. Further, by controlling the offset of the friction of the workpiece rotating shaft and the pressing force on both tooth surfaces by speed control and torque limitation, it is possible to obtain a uniform polishing amount.
[0126]
Further, in the third control mode, although the rotation position is synchronously controlled, the tooth alignment can be automated.
[0127]
These not only polish the workpiece but also press the vibration of the motor during dressing, and can suppress the occurrence of irregularities and undulations on the tooth surface of the internal grindstone.
[0128]
Also in the third control mode, as in the first embodiment, it is possible to apply a large thrust without losing the cutting force to the pressing force by the tail spindle 22 for holding the workpiece. Even when the cutting load is increased, the tail stock does not retreat and the posture of the workpiece does not collapse, and a higher orthodontic force than before can be achieved with high accuracy in a short time. Further, it is not necessary to switch the thrust by the tailstock 12 during workpiece polishing and dressing.
[0129]
In the second embodiment, the signal of the encoder attached to the S-axis motor is used to obtain the rotational speed and rotational position of the internal grindstone. Instead, the internal grindstone is used. You may make it detect the rotational speed and rotational position of an internal grindstone directly by attaching an encoder to itself.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an external configuration of a gear honing machine according to a first embodiment to which the present invention is applied.
FIG. 2 is a schematic view for explaining the gear honing machine.
FIG. 3 is a drawing schematically showing a tail stock and a wedge portion of the gear honing machine.
FIG. 4 is a perspective view showing an external configuration of a gear honing machine according to a second embodiment to which the present invention is applied.
FIG. 5 is a schematic view for explaining the gear honing machine.
FIG. 6 is a block diagram of a control system for explaining a first control mode for controlling a gear and honing machine in a second embodiment.
FIG. 7 is a block diagram of a control system for explaining a second control mode for controlling the gear and honing machine in the second embodiment.
FIG. 8 is a block diagram of a control system for explaining a third control mode for controlling the gear and honing machine in the second embodiment.
FIG. 9 is a schematic view showing a meshing portion between an internal grindstone and a workpiece.
[Explanation of symbols]
1, 51 ... Gear honing machine
2 ... Work
3 ... Internal whetstone
11 ... Headstock
12 ... Tailstock
13 ... Whetstone head unit
15 ... Machine bed
16 ... Table
17 ... Hydraulic cylinder
18 ... Rail
19 ... S-axis motor
20 ... Work axis
21 ... Head spindle
22 ... Tail spindle
23 ... Bearing
24 ... Case
25 ... Rail
29 ... Encoder
30 ... Tailstock support
31 ... Tail stock rear slope
32 ... Wedge member
33 ... Hydraulic cylinder
34 ... post
35 ... Rail
52 ... C-axis motor
53 ... Encoder
54 ... Coupling device
55 ... Chuck
61 ... Current detector
62 ... Comparator
62 ... Current controller
65 ... Speed detector
66, 68, 72 ... comparator
67 ... Speed controller
69 ... Current controller
71 ... Gain adjuster
73 ... Position controller

Claims (3)

A workpiece in which a tooth profile is formed in advance is rotatably held, and the workpiece and the grinding wheel are rotated relative to each other while a grinding stone shaped in a shape corresponding to the tooth profile is brought into contact with the teeth of the workpiece. In the gear honing machine that polishes the workpiece,
First holding means for holding one end of a work shaft to which the work is attached;
Second holding means that holds the other end of the work shaft and is movable in a reciprocating manner to sandwich the work shaft with the first holding means;
Thrust generating means for pressing the second holding means against the other end of the work shaft with a predetermined thrust;
Retreat prevention means for preventing retraction of the second holding means;
I have a,
The retreat prevention means is
A wedge member formed with an inclined surface in contact with the rear of the second holding means opposite to the side holding the other end of the work shaft in the second holding means;
Elevating means for elevating and lowering the wedge member, and the wedge member is lowered by the elevating means after a predetermined thrust is applied to the second holding means by the thrust generating means, and the wedge is lowered. A gear honing machine characterized in that a force obtained from a mass applied to the member and the wedge member of the elevating means is applied to contact the rear part of the second holding means . The force obtained from the mass applied to the wedge member and the wedge member of the elevating means when the wedge member is brought into contact with the rear portion of the second holding means,
2. The gear honing machine according to claim 1 , wherein an upward force applied to the wedge member by the rear portion of the second holding means is larger . The thrust generating means includes
3. The gear according to claim 1, wherein a thrust is generated to the extent that the workpiece rotates so that the teeth shaped on the grindstone can come into contact with both surfaces of the teeth of the workpiece with an equal force. Honing machine.

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