JP2004017255A - Gear grinding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a cycle time of grinding by automatically meshing a gear grinding tool having a plurality of spiral bars with a gear to be ground. <P>SOLUTION: A Z-phase signal Eb showing a zero position of a gear grinding tool 42 having two spiral bars is converted into a Z-phase pulse doubling signal Ed having double pulses by a pulse doubling part 109. An A-phase signal Ea showing a rate of change of rotation of the gear grinding tool 42 is counted by a second counter 116 in a time of a shaping pulse PO showing passage of each tooth of a ground gear 22 and the Z-phase pulse doubling signal Ed. At an initial teaching time, a phase of the gear grinding tool 42 is matched with that of the ground gear 22, so as to the number N1 of store a phase pulses of the second counter 116 as the number N0 of store phase pulses. A counter memory circuit 118 forms a coincidence signal ST1 when the number N1 of the phase pulses is equal to the number N0 of the store phase pulses. A rotation control part 104 synchronously or asynchronously rotates the gear 22 to be ground, based on the coincidence signal ST1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gear grinding apparatus, and in particular, when meshing a gear to be ground with a gear grinding tool having a helical strip, automatically adjusts the phase by keeping the gear to be ground and the gear grinding tool in phase. The present invention relates to a gear grinding device for meshing.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a gear grinding apparatus, a spiral streak of a gear grinding tool is synchronously rotated while meshing with a tooth groove of a gear to be ground. By moving this gear grinding tool forward and backward relative to the gear to be ground, the tooth surface of the gear to be ground can be ground with a spiral strip.
[0003]
In this type of gear grinding apparatus, when replacing the gear to be ground to be ground, the rotation of the gear grinding tool is stopped before replacing the gear to be ground, so that the rotation of the gear grinding tool is reduced, stopped, and stopped. Since re-acceleration is repeatedly performed, the cycle time of the grinding process becomes long, which is inefficient.
[0004]
Therefore, there has been proposed a technique in which the rotation of the gear to be ground is synchronized with the rotation of the gear grinding tool, and the phases of the gear to be ground and the gear grinding tool are matched to automatically engage with each other (Japanese Patent Publication No. Sho 62-38089). And Japanese Patent No. 2718850). Specifically, a phase between the timing of detecting the zero point position on the rotation of the gear grinding tool and the timing of detecting each tooth of the gear to be ground is recognized, and the timing difference is a value taught in advance. Are made to coincide with each other.
[0005]
According to these techniques, the cycle time of the grinding process can be shortened by engaging the gear grinding tool and the gear to be ground without stopping the rotation of the gear grinding tool. As a result, a large number of gears to be ground can be ground within a predetermined time, so that the production efficiency of the gear grinding processing is improved.
[0006]
[Problems to be solved by the invention]
Recently, it has been desired that the cycle time for grinding the gear to be ground (grinding time and replacement time of the gear to be ground) be further increased. For this reason, adoption of a gear grinding tool having a plurality of spiral strips has been promoted. For example, as shown in FIG. 9, if a gear grinding tool 200 having two spiral threads 202a and 202b is used, the rotation speed of the gear to be ground 204 can be doubled, and the grinding time is greatly reduced. Shortening is possible.
[0007]
However, the conventional automatic meshing technique has been developed for a gear grinding tool having one helical strip, and if applied directly to a gear grinding tool 200 having two helical strips, a problem occurs. That is, even if an attempt is made to recognize each other's phase based on the difference between the timing of detecting the zero point position on the rotation of the gear grinding tool 200 and the timing of detecting each tooth of the gear to be ground 204, one rotation of the gear grinding tool 200 is performed. In this case, each tooth of the gear to be ground 204 is detected twice, so that processing is impossible or erroneous processing is performed at the second detection.
[0008]
On the other hand, if the gear to be ground is meshed after the gear grinding tool 200 is stopped without performing automatic meshing, the cycle time becomes longer, which is against the purpose of speeding up.
[0009]
Therefore, based on the conventional automatic meshing technique, that is, a gear grinding apparatus having a plurality of spiral strips based on a gear grinding apparatus for automatically meshing with a gear to be ground using a gear grinding tool having one spiral strip. Preferably, a tool can be applied.
[0010]
The present invention has been made in view of such problems, and enables automatic reduction of a grinding cycle time by performing automatic meshing between a gear grinding tool having a plurality of spiral threads and a gear to be ground. It is an object of the present invention to provide a gear grinding device.
[0011]
[Means for Solving the Problems]
The gear grinding device according to the present invention is configured to synchronously rotate a gear grinding tool having two or more spiral streaks and a gear to be ground, and to engage the tooth to be ground while meshing the spiral streaks with the tooth grooves of the gear to be ground. In a gear grinding apparatus for grinding a gear for use, a zero point position and a rotation change amount of the gear grinding tool are detected, and a pulse generator that outputs each as a pulse, and each tooth that passes along with the rotation of the gear to be ground. A tooth tip detection sensor that detects and outputs a pulse and a pulse indicating the zero point position output by the pulse generator are input, and outputs a pulse corresponding to the number of the spiral strips in response to the input pulse. A pulse doubling unit, and a rotation change amount of the gear grinding tool between a timing at which the pulse doubling unit outputs a pulse and a timing at which a pulse value output from the tooth tip detection sensor switches. A counter that counts the indicated pulses as the number of phase pulses, and a storage unit that stores the number of phase pulses as a stored phase pulse number when the phases of the gear to be ground and the gear grinding tool match, A phase match determination unit that determines whether the number of phase pulses newly counted by the counter matches the number of stored phase pulses, and when the number of newly counted phase pulses matches the number of stored phase pulses. A rotation control unit that synchronously rotates the gear to be ground and asynchronously rotates the gear to be ground when the newly counted number of phase pulses does not match the number of stored phase pulses. And
[0012]
As described above, the pulse at the zero point detected by the pulse generator is doubled by the pulse doubling unit to the number of spiral streaks, so that the timing at which each tooth of the gear to be ground is detected and the pulse doubling unit outputs a pulse. The timings correspond one-to-one, and the phase between the gear to be ground and the gear grinding tool can be detected. Therefore, by making the phases coincide, automatic engagement between the gear grinding tool having a plurality of spiral strips and the gear to be ground becomes possible, and the cycle time of grinding can be shortened.
[0013]
In this case, the pulse doubling unit counts the pulse indicating the rotation change amount, and the count value divides the number of pulses of the rotation change amount per rotation of the gear grinding tool by the number of the spiral strips. It is preferable to output a pulse every time the value becomes an integer multiple thereof.
[0014]
With this configuration, the interval between the timing at which each tooth of the gear to be ground is detected and the timing at which the pulse doubling unit outputs a pulse is accurately defined, and phase detection can be performed more precisely. .
[0015]
Further, the pulse doubling unit may be a multiplying circuit that outputs a pulse having a frequency that is an integral multiple of the pulse frequency indicating the zero point position. Thus, the pulse doubling unit can be easily configured.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of a gear grinding device according to the present invention will be described with reference to FIGS.
[0017]
As shown in FIG. 1, the gear grinding device 10 according to the present embodiment includes a grinding section 10a that performs a grinding process, and a control section 10b that controls the operation of the grinding section 10a. The control unit 10b includes a control circuit 100 (see FIG. 4) for controlling an automatic meshing operation described later.
[0018]
In the grinding section 10a, a cutting table 14 is disposed on the upper surface of the bed 12, and the cutting table 14 moves forward and backward in the direction of the arrow X under the rotation of the cutting motor 16. The traverse table 18 provided on the upper surface of the cutting table 14 moves forward and backward in a direction perpendicular to the arrow X direction, that is, in the arrow Z direction under the rotation of the traverse motor 20.
[0019]
Further, on the traverse table 18, a gear 22 to be ground having a tooth profile formed in advance is detachably disposed, and a convex portion of the tooth of the gear 22 to be rotated is detected to detect the gear. A tooth tip detection sensor 24 composed of a proximity switch for generating a pulse is provided. The gear 22 to be ground rotates under the rotation of the work spindle motor 26, and the axis of this rotation is set to coincide with the direction of movement of the traverse table 18.
[0020]
On the other hand, a column 28 is disposed in the traveling direction of the cutting table 14 and on the bed 12, and the turning table 30 is held by the column 28. The swivel table 30 can be swiveled in the direction of arrow C by a swivel motor 31 disposed in the column 28. Further, the swivel table 30 is provided with a shift table 32, which is operated by a shift motor 34. And can be moved in the direction of arrow D.
[0021]
As schematically shown in FIG. 2, the shift table 32 is provided with a tool spindle unit 36. The tool spindle unit 36 basically includes a tool spindle motor 38, a tool shaft 41 rotated by the tool spindle motor 38, and a first pulse generator 46 for detecting the rotation of the tool shaft 41.
[0022]
The first pulse generator 46 outputs an A-phase signal Ea that generates a pulse according to the rotation change amount of the tool shaft 41, and a Z-phase signal Eb that indicates a zero point position on the rotation of the tool shaft 41.
[0023]
The gear grinding tool 42 which rotates under the action of the tool spindle motor 38 has a cylindrical shape, and is provided with two spiral threads 47a and 47b made of a grindstone for grinding the gear 22 to be ground on its peripheral edge. The spiral strips 47a and 47b move a distance equivalent to two pitches (two teeth) of the gear 22 to be ground per rotation of the tool shaft 41.
[0024]
On the other hand, a tool spindle unit 36 is mounted on the shift table 32. The shift table 32 is connected to a ball screw 35, and the ball screw 35 is rotated by a shift motor 34. Accordingly, the tool spindle unit 36 and the gear grinding tool 42 are displaced in the direction of arrow D together with the shift table 32 under the driving action of the shift motor 34.
[0025]
The cutting motor 16, the traverse motor 20, the work spindle motor 26, and the tool spindle motor 38 are stepping motors, and rotate according to the number of pulses supplied from the control unit 10b. The rotation angle per pulse is a minute angle, and precise rotation control is performed based on the number of supplied pulses.
[0026]
As shown in FIG. 3, the gear 22 to be ground is detachably supported by a pair of clamp jigs 50. The clamp jig 50 is connected to one end of an electromagnetic clutch 51 for connecting or disconnecting rotation, and the other end of the electromagnetic clutch 51 is connected to a traction drive 52 as a power transmission mechanism. The traction drive 52 is connected to one end of the work spindle motor 26 via a rotation shaft 53. At the other end of the work spindle motor 26, a second pulse generator 54 for detecting the rotation amount of the rotating shaft 53 is provided. The rotation shaft 53 is provided with an inertia damper 56 having a function of stabilizing rotation.
[0027]
As shown in FIG. 4, a control circuit 100 that controls the automatic meshing operation receives signals from the tooth tip detection sensor 24 and the first pulse generator 46, and controls the cutting motor 16, the work spindle A control signal is output to the motor 26 and the electromagnetic clutch 51.
[0028]
The control circuit 100 processes the output signals of the tooth tip detection sensor 24 and the first pulse generator 46, and determines the coincidence or non-coincidence of the phase between the gear 22 to be ground and the gear grinding tool 42. And a rotation control unit 104 that controls the rotation of the work spindle motor 26 in accordance with the coincidence signal ST1 and the non-coincidence signal ST2 output from the input signal processing unit 102. Further, the control circuit 100 controls the cutting mechanism control unit 106 for enabling or disabling the operation of the cutting motor 16 in accordance with the phase matching signal ST1, and the electromagnetic clutch 51 so that the work spindle motor 26 And a clutch control unit 108 for connecting and disconnecting the gear 22. Further, the control circuit 100 includes a pulse doubling unit 109 that increases the number of pulses of the Z-phase signal Eb output from the first pulse generator 46 to the number of spiral strips and outputs the number.
[0029]
The pulse doubling unit 109 receives the A-phase signal Ea and the Z-phase signal Eb and performs a counting process, and receives the count signal Ec and the Z-phase signal Eb output from the first counter 160. A first OR gate 162 for outputting a logical sum of the Z-phase pulse multiplication signal Ed, and a dip switch 164 for setting processing in the first counter 160.
[0030]
The first counter 160 is reset every time the Z-phase pulse doubling signal Ed rises, and thereafter counts the number of pulses of the A-phase signal Ea. Each time the count value reaches the value G set by the DIP switch 164 and its integral multiple, that is, G times, 2 × G times, 3 × G times,..., The logical value of the count signal Ec Is switched from “0” to “1” for a predetermined short time (for example, a time corresponding to one pulse of the A-phase signal Ea). The value G set by the dip switch 164 is set as a value obtained by dividing the resolution (the number of pulses per rotation) of the A-phase signal Ea by the number of teeth of the gear grinding tool 42.
[0031]
When the Z-phase signal Eb rises (logical value “1”), the first counter 160 is reset, so that the count signal Ec has the logical value “0”. On the other hand, since the Z-phase signal Eb has the logical value “1”, the first OR gate 162 outputs the Z-phase pulse doubling signal Ed as a logical sum as the logical value “1”.
[0032]
That is, while the gear grinding tool 42 makes one rotation, the Z-phase signal Eb appears once in the form of a pulse (see FIG. 5), and this pulse is doubled by the pulse doubling unit 109 to the number of spiral strips of the gear grinding tool 42. (See FIG. 5), the signal is output as the Z-phase pulse doubling signal Ed.
[0033]
In the present embodiment, since the gear grinding tool 42 has two spiral strips 47a and 47b, as shown in FIG. 5, the number of pulses included in the Z-phase pulse doubling signal Ed is equal to the number of pulses of the Z-phase signal Eb. It is twice the number. Further, when the pulses of the A-phase signal Ea are at equal intervals, that is, when the gear grinding tool 42 is rotating at a constant speed, the pulses included in the Z-phase pulse doubling signal Ed are pulses at equal intervals.
[0034]
Returning to FIG. 4, the input signal processing unit 102 includes a waveform shaping circuit 110 that outputs a shaped pulse P0 obtained by shaping the distorted pulse waveform output from the tooth tip detection sensor 24 into a square, a Z-phase pulse doubled signal Ed, and a shaped pulse. The second counter 116 counts the A-phase signal Ea based on the timing of P0 and outputs the count value as the number N1 of phase pulses, and the phase supplied based on the doubled-phase Z-phase signal Ed and the shaped pulse P0. A counter memory circuit 118 (phase coincidence determination unit) for storing the pulse number N1 as the storage phase pulse number N0 and comparing the storage phase pulse number N0 with the newly supplied phase pulse number N1. When the distortion included in the pulse waveform output from the tooth tip detection sensor 24 is small, the waveform shaping circuit 110 may be omitted.
[0035]
A teaching switch (not shown) is connected to the counter memory circuit 118. When the teaching switch is turned on, the phase pulse number N1 is stored as the storage phase pulse number N0, and the storage phase pulse is stored. An allowable width w sufficiently smaller than the number N0 is calculated. The storage phase pulse number N0 and the allowable width w are stored in the storage unit 118a. The allowable width w is a reference value for allowing a slight phase shift while the grinding gear 22 is being ground. The storage unit 118a may be provided outside the counter memory circuit 118. The allowable width w may be a predetermined constant based on a general numerical value of the number N0 of storage phase pulses.
[0036]
The counter memory circuit 118 compares the number N1 of phase pulses supplied from the second counter 116 with the number N0 of stored phase pulses when the shaped pulse P0 rises. When the number N1 of phase pulses and the number N0 of stored phase pulses match, the coincidence signal ST1 to be output is set to the logical value “1”, and the mismatch signal ST2 is set to the logical value “0”. When the number N1 of phase pulses and the number N0 of stored phase pulses do not match, the coincidence signal ST1 is set to a logical value “0”, and the mismatch signal ST2 is set to a logical value “1”.
[0037]
However, since the gear 22 to be ground has heat treatment distortion in the heat treatment step, it is necessary to allow a slight phase shift. Therefore, while the grinding gear 22 is being ground, as shown in FIG. 5, if the number N1 of phase pulses is within the range of N0 ± w, the coincidence signal ST1 is held as the logical value “1”. I do.
[0038]
FIG. 5 shows a time chart of the A-phase signal Ea, the Z-phase signal Eb, the count signal Ec, the Z-phase pulse doubling signal Ed, the shaping pulse P0, and the coincidence signal ST1 while the grinding gear 22 is being ground. . In FIG. 5, a signal serving as a reference for the number N1 of phase pulses is represented as an internal signal Q. The internal signal Q is a signal having a logical value “1” while the number of pulses of the A-phase signal Ea from the rise of the Z-phase pulse doubling signal Ed (for example, time t0) is N0 ± w. When the frequency-divided signal F rises (for example, at time t1), the counter memory circuit 118 compares the number N1 of phase pulses supplied from the second counter 116 with N0 ± w. If it is within the range, the coincidence signal ST1 is set to the logical value “1”. The mismatch signal ST2 (see FIG. 4) is output as the inverse logic of the match signal ST1.
[0039]
As described above, the phase confirmation processing in the counter memory circuit 118 is executed by the shaping pulse P0. The shaping pulse P0 is given as two pulses during one rotation of the gear grinding tool 42. On the other hand, the numerical value serving as the basis for confirming the phase is the number N1 of phase pulses, and the number N1 of phase pulses is counted based on the Z-phase pulse doubling signal Ed. Since the Z-phase pulse doubling signal Ed is given as two pulses during one rotation of the gear grinding tool 42, and the interval between the pulses is an interval corresponding to the rotation amount of the gear grinding tool 42, One rise of the Z-phase pulse doubling signal Ed corresponds to one rise of the shaping pulse P0, so that accurate phase confirmation is performed.
[0040]
If the pulse doubling unit 109 is not provided, the Z-phase signal Eb is supplied to the counter memory circuit 118, and when the second shaped pulse P0 is supplied after the rising of the Z-phase signal Eb (for example, at time t2). Processing cannot be performed or erroneous processing will be performed. In the present embodiment, such a situation can be avoided by the pulse doubling section 109 doubling the pulse of the Z-phase signal Eb and supplying it to the counter memory circuit 118.
[0041]
Further, at the time of the rising of the shaping pulse P0, that is, each time the teeth of the gear to be ground 22 are detected, it is possible to confirm the coincidence of the phases, so that more accurate phase matching can be performed.
[0042]
Note that while the grinding gear 22 is being ground, the coincidence signal ST1 always has a logical value "1", but in FIG. 5, for the sake of convenience, the coincidence signal ST1 is logically at time t1. Values are shown to change.
[0043]
Referring back to FIG. 4, the rotation control unit 104 is supplied with the A-phase signal Ea of the first pulse generator 46, divides the A-phase signal Ea, and outputs divided pulses P1 and P2. And a first AND gate 122 to which the frequency division pulse P1 and the coincidence signal ST1 are input, and a second AND gate 124 to which the frequency division pulse P2 and the non-coincidence signal ST2 are input. Further, the rotation control unit 104 amplifies the second OR gate 126 to which the AND signal output from each of the first and second AND gates 122 and 124 is input, and the OR signal output from the second OR gate 126. And a first amplifier 128 for rotating the work spindle motor 26.
[0044]
The index calculation circuit 120 is provided with a constant setting section (not shown). The constant setting section includes the number of teeth of the gear grinding tool 42, the number of teeth of the gear 22 to be ground, and the traction drive. A speed reduction ratio of 52 is set. The index calculation circuit 120 calculates the synchronous rotation speed ratio α between the gear grinding tool 42 and the work spindle motor 26 based on these set values. The index calculation circuit 120 outputs a signal obtained by dividing the pulse train of the input A-phase signal Ea by the synchronous rotation speed ratio α as a divided pulse P1.
[0045]
Further, a constant δ having an absolute value smaller than the synchronous rotation speed ratio α is set in the index calculation circuit 120, and a signal obtained by dividing the pulse train of the input A-phase signal Ea by (α + δ) is divided into a divided pulse P2. Is output as
[0046]
With such a configuration of the rotation control unit 104, when the phase of the gear to be ground 22 and the phase of the gear grinding tool 42 match, the first AND gate 122 is enabled by the match signal ST1, and the frequency-divided pulse P1 is changed to the first pulse. After passing through the 1 AND gate 122, it is supplied to the work spindle motor 26 via the second OR gate 126 and the first amplifier 128. As a result, when the phase of the gear 22 to be ground and the phase of the gear grinding tool 42 coincide, the gear 22 to be ground rotates at a synchronous speed under the action of the work spindle motor 26.
[0047]
Further, when the phase of the gear 22 to be ground and the phase of the gear grinding tool 42 do not match, the second AND gate 124 is enabled by the mismatch signal ST2, the frequency-divided pulse P2 passes through the second AND gate 124, and It is supplied to the work spindle motor 26 via the OR gate 126 and the first amplifier 128. As a result, when the phases of the gear 22 to be ground and the gear grinding tool 42 do not match, the gear 22 to be ground rotates at a speed slightly different from the synchronous speed (asynchronous speed) under the action of the work spindle motor 26. When the grinding gear 22 rotates at an asynchronous speed, the phases of the grinding gear 22 and the gear grinding tool 42 eventually coincide.
[0048]
The cutting mechanism control unit 106 includes a third counter 132 and a cutting instruction circuit 134 for instructing the rotation speed of the cutting motor 16. Further, the cutting mechanism control unit 106 amplifies a third AND gate 136 to which the output signal of the third counter 132 and the pulse train P3 are input, and an AND signal output by the third AND gate 136 to perform the cutting. A second amplifier 138 for rotating the motor 16.
[0049]
The third counter 132 counts the number of oscillation pulses of the oscillation circuit 130 when the coincidence signal ST1 has the logical value “1”, and after the count value reaches K times which is a predetermined constant, the logical value “1”. , And acts as a kind of delay timer. The cut instruction circuit 134 outputs a pulse train P3 that regulates the rotation of the cut motor 16.
[0050]
When the third counter 132 outputs the logical value “1”, the third AND gate 136 becomes valid. At this time, the pulse train P3 is supplied to the cutting motor 16 via the third AND gate 136 and the second amplifier 138, and the cutting motor 16 rotates. Note that a forward / reverse rotation instruction signal (not shown) for specifying the rotation direction is supplied to the cut motor 16, and the cut motor 16 rotates in the direction specified by the forward / reverse rotation instruction signal.
[0051]
When the coincidence signal ST1 has the logical value “0”, or when the coincidence signal ST1 has the logical value “1” but the period does not reach K times of the oscillation pulse, the third counter 132 clears the count. At the same time, the output signal is set to the logical value “0”. Therefore, the pulse train P3 is cut off by the third AND gate 136.
[0052]
The oscillation pulse supplied to the third counter 132 is not limited to the one generated by the oscillation circuit 130, but may be the Z-phase signal Eb or the shaped pulse P0.
[0053]
The clutch control unit 108 includes a connection determination unit 140 that determines connection and disconnection of the electromagnetic clutch 51, and a third amplifier that amplifies an output signal of the connection determination unit 140 to control the electromagnetic clutch 51 and perform connection and disconnection. 142.
[0054]
Next, a method of performing the grinding by automatically meshing the gear to be ground 22 and the gear grinding tool 42 using the gear grinding apparatus 10 configured as described above will be described with reference to FIGS. 6 and 7.
[0055]
First, in step S1 of FIG. 6, the electromagnetic clutch 51 is turned off by the operation of the clutch control unit 108 to disconnect the work spindle motor 26 from the grinding gear 22. As a result, the grinding gear 22 can be manually turned. The tool spindle motor 38 is stopped.
[0056]
Next, in step S2, the cutting motor 16 is rotated to advance the cutting table 14 (see FIG. 1) at a low speed. When the cutting table 14 moves forward, the gear 22 to be ground is manually rotated to guide the tooth grooves of the gear 22 to be ground so that the spiral grooves 47a and 47b of the gear grinding tool 42 mesh with each other. After the tooth groove of the gear to be ground 22 and the spiral ridges 47a and 47b of the gear grinding tool 42 are securely engaged, the forward movement of the cutting table 14 is stopped.
[0057]
Next, in step S3, the tool spindle motor 38 is rotated at a low speed. The gear grinding tool 42 is rotated by the tool spindle motor 38, and the gear 22 to be ground engaged with the gear grinding tool 42 is also driven to rotate.
[0058]
At this time, the Z-phase signal Eb is shaped by the pulse doubling unit 109 into a Z-phase pulse doubling signal Ed having a doubled pulse, and is supplied to the input signal processing unit 102.
[0059]
Incidentally, the Z-phase pulse doubling signal Ed (see FIG. 5) generates two pulses per rotation of the gear grinding tool 42. On the other hand, since the gear 22 to be rotated rotates by two pitches (the number of two teeth) per rotation of the gear grinding tool 42, two shaping pulses P0 are also generated. As a result, the number of pulse generations in each of the Z-phase pulse doubling signal Ed and the shaped pulse P0 becomes the same.
[0060]
The second counter 116 clears the number of phase pulses N1 up to the previous time when the Z-phase pulse doubling signal Ed rises, starts counting the number of pulses of the A-phase signal Ea, and continues counting until the rising of the shaped pulse P0. The newly counted number N1 of phase pulses is supplied to the counter memory circuit 118 (see FIG. 4).
[0061]
Further, in step S4, teaching of phase matching is performed. Specifically, the teaching switch is turned on, and the number N1 of phase pulses is stored in the counter memory circuit 118. When recognizing that the teaching switch has been turned on, the counter memory circuit 118 stores the number of phase pulses N1 supplied immediately thereafter as the number of stored phase pulses N0 and calculates the allowable width w.
[0062]
Next, in step S5, the cutting table 14 (see FIG. 1) is moved backward. The gear 22 to be ground is separated from the gear grinding tool 42 and then stops. At this time, the counter memory circuit 118 holds the stored phase pulse number N0 and the allowable width w.
[0063]
Next, in step S6, the electromagnetic clutch 51 is turned on, and the work spindle motor 26 and the grinding gear 22 are connected.
[0064]
Further, in step S7, the tool spindle motor 38 is energized to rotate the gear grinding tool 42 at a specified speed. Further, the work spindle motor 26 is biased by the rotation control unit 104 to rotate the gear 22 to be ground via the electromagnetic clutch 51 in the connected state.
[0065]
At this time, the second counter 116 of the input signal processing unit 102 counts the number N1 of phase pulses from the rising of the doubled Z-phase pulse signal Ed to the rising of the shaped pulse P0. The number N1 of phase pulses is supplied to the counter memory circuit 118.
[0066]
As described above, in the counter memory circuit 118, when the number N1 of phase pulses matches the number N0 of stored phase pulses, the coincidence signal ST1 is set to the logical value “1” and the non-coincidence signal ST2 is set to the logical value “0”. When the number N1 of phase pulses and the number N0 of stored phase pulses do not match, the coincidence signal ST1 is set to a logical value “0”, and the mismatch signal ST2 is set to a logical value “1”. At this point, the allowable width w is not referred to.
[0067]
Generally, in the initial state, the phase of the gear 22 to be ground and the gear grinding tool 42 are relatively large, so that the number N1 of phase pulses and the number N0 of stored phase pulses do not match, and the coincidence signal ST1 has the logical value “ 0 ", and the mismatch signal ST2 has a logical value" 1 ".
[0068]
The first AND gate 122 (see FIG. 4) of the rotation control unit 104 becomes invalid because the input coincidence signal ST1 has the logical value “0”. Accordingly, the frequency division pulse P1 input to the first AND gate 122 is cut off. On the other hand, the second AND gate 124 (see FIG. 4) becomes valid because the input non-coincidence signal ST2 has the logical value "1". The frequency-divided pulse P2 input to the second AND gate 124 passes through the second AND gate 124 and the second OR gate 126, is amplified by the first amplifier 128, and is supplied to the work spindle motor 26 (see FIG. 4). The frequency-divided pulse P2 is a signal obtained by frequency-dividing the A-phase signal Ea by a value (α + δ) obtained by adding the synchronous rotation speed ratio α and the constant δ. It will rotate at a speed slightly different from the speed.
[0069]
Further, since the coincidence signal ST1 has the logical value “0”, the third counter 132 (see FIG. 4) of the cutting mechanism control unit 106 is invalid, and as a result, the cutting motor 16 is not driven and the cutting The table 14 holds the stopped state. That is, the third counter 132 exerts a kind of interlock action on the cutting mechanism.
[0070]
Further, in this step S7, a counter (not shown) for counting the number of output pulse signals of the second pulse generator 54 (see FIG. 3) in one cycle of the signal of the shaping pulse P0 is used for grinding. An erroneous attachment of the gear 22 may be detected.
[0071]
Next, in step S8 of FIG. 7, the counter memory circuit 118 sets the coincidence signal ST1 to the logical value “0” and the non-coincidence signal ST2 to the logical value “1” until the number of phase pulses N1 and the number of stored phase pulses N0 match. Output. During this time, since the gear 22 to be ground is rotating at a speed slightly different from the synchronous speed, the phases of the gear 22 to be ground and the gear grinding tool 42 eventually coincide.
[0072]
Next, in step S9, when the number N1 of phase pulses matches the number N0 of stored phase pulses, the counter memory circuit 118 inverts the coincidence signal ST1 and the non-coincidence signal ST2. That is, the coincidence signal ST1 is output as a logical value “1”, and the non-coincidence signal ST2 is output as a logical value “0”.
[0073]
The second AND gate 124 of the rotation control unit 104 becomes invalid because the input mismatch signal ST2 has the logical value “0”. Accordingly, the frequency division pulse P2 input to the second AND gate 124 is cut off. On the other hand, the first AND gate 122 is enabled because the input match signal ST1 has the logical value “1”. The frequency-divided pulse P1 input to the first AND gate 122 passes through the first AND gate 122 and the second OR gate 126, is amplified by the first amplifier 128, and is supplied to the work spindle motor 26. Since the frequency-divided pulse P1 is a signal obtained by frequency-dividing the A-phase signal Ea by the synchronous rotation speed ratio α, as a result, the grinding gear 22 rotates at the synchronous speed.
[0074]
Further, since the coincidence signal ST1 has the logical value “1”, the third counter 132 of the cutting mechanism control unit 106 is enabled, and the counting of the oscillation pulse output from the oscillation circuit 130 is started.
[0075]
Next, in step S10, the process waits until the count value of the third counter 132 of the cutting mechanism control unit 106 reaches K times. After the count value reaches K times, the third counter 132 outputs the logical value “1”, and proceeds to the next step S13. However, if the input coincidence signal ST1 becomes a logical value "0" before the count value reaches K times (step S11), the counting is stopped at that time and the count value is cleared (step S12). In this case, the process returns to step S8.
[0076]
In step S13, since the output signal of the third counter 132 has the logical value “1”, the third AND gate 136 to which the output signal is input becomes valid. Accordingly, the pulse train P3 output from the cutting instruction circuit 134 is supplied to the cutting motor 16 after being amplified by the second amplifier 138 via the third AND gate 136. Thereby, the cutting motor 16 is energized and the cutting table 14 moves forward.
[0077]
At this time, the phases of the gear 22 to be ground and the gear grinding tool 42 match, so that the spiral strips 47a and 47b of the gear grinding tool 42 automatically mesh with the tooth grooves of the gear 22 to be ground. That is, automatic meshing can be performed while the gear to be ground 22 and the gear grinding tool 42 are rotating.
[0078]
In addition, since the automatic meshing is not performed immediately after the coincidence signal ST1 becomes the logical value "1", the apparatus waits for a period until the count value of the third counter 132 reaches K times (the step S10). The automatic meshing can be performed in a state where the phases of the gear 22 and the gear grinding tool 42 match and the synchronous rotation is stable.
[0079]
Next, in step S14, the tooth surface of the gear 22 to be ground is ground by the spiral strips 47a and 47b by moving the cutting table 14 to a predetermined position. At this time, since the grinding is performed by the two spiral strips 47a and 47b, the grinding can be performed faster than in the case of the single spiral strip.
[0080]
Further, since the grinding gear 22 receives a load caused by grinding from the spiral threads 47a and 47b, the phase between the gear grinding tool 42 and the grinding gear 22 is slightly shifted. In order to allow this phase shift, the counter memory circuit 118 compares the number of phase pulses N1 with a value obtained by adding the width of the allowable width w to the number of stored phase pulses N0. That is, if the number N1 of phase pulses is within the range of N0 ± w, the coincidence signal ST1 is continuously output as the logical value “1”.
[0081]
Next, in step S15, after the grinding of the gear 22 to be ground at this point is completed, the cutting table 14 is retracted, and the electromagnetic clutch 51 is turned off. As a result, the rotation of the grinding gear 22 that has finished grinding is stopped, and the grinding gear 22 is removed from the clamp jig 50 (see FIG. 3) (step S16).
[0082]
Further, in step S17, it is determined whether or not grinding has been completed for all of the gears 22 to be ground. When the grinding of all the gears 22 to be ground is completed, the tool spindle motor 38 and the work spindle motor 26 are stopped, and the grinding process is completed.
[0083]
If there is an unground grinding gear 22, the grinding gear 22 is mounted on the clamp jig 50 (see FIG. 3) (step S18), and the process returns to step S6. In this case, since the tool spindle motor 38 keeps rotating, there is no standby time required for acceleration / deceleration, and the process can be shifted to the grinding process quickly. At this point, the stored phase pulse number N0 and the allowable width w have already been set, so that it is not necessary to perform the initial teaching process (steps S1 to S5) for phase confirmation again.
[0084]
Next, a modified example of the gear grinding device 10 according to the present embodiment will be described with reference to FIG.
[0085]
As shown in FIG. 8, the pulse doubling unit 109 in this modification includes a multiplier 180 that outputs a frequency signal of an integral multiple of the input signal frequency, a dip switch 182 that sets the multiplier of the multiplier 180, Having.
[0086]
The multiplier 180 is a circuit that obtains an integer multiple frequency by using a harmonic component of an input signal. With this function, the frequency of the input Z-phase signal Eb is determined based on the setting of the dip switch 182. , And output as a Z-phase pulse multiplied signal Ee. The setting of the dip switch 182 is set to “2” in accordance with the number of the spiral strips 47 a and 47 b of the gear grinding tool 42. Therefore, since the Z-phase pulse multiplied signal Ee is a signal having a frequency twice as high as the Z-phase signal Eb, when the gear grinding tool 42 is rotating at a constant speed, the Z-phase pulse multiplied signal Ee becomes the Z-phase pulse multiplied. The signal has the same frequency as the signal Ed (see FIG. 5).
[0087]
Actually, since the gear grinding tool 42 rotates at a constant speed, it is possible to use the Z-phase pulse multiplied signal Ee instead of the Z-phase pulse multiplied signal Ed. The automatic meshing between the gear grinding tool 42 and the gear 22 to be ground can be performed in the same manner as in the above embodiment.
[0088]
In this case, the pulse doubling unit 109 can be constituted by a simple circuit including the multiplier 180 and the dip switch 182, and further, since there is no need to refer to the A-phase signal Ea, the print signal line and the branch The number can be reduced.
[0089]
In the multiplier 180, the Z-phase signal Eb may be once frequency-divided by 2 so as to be easily shaped, and then quadrupled.
[0090]
The control circuit 100 used in the gear grinding device 10 according to the present embodiment and its modified example is a conventional technology, that is, automatic meshing with a gear to be ground using a gear grinding tool having one spiral spiral. Can be used as a base. That is, the pulse doubling unit 109 may be added to the input processing unit of the A-phase signal Ea and the Z-phase signal Eb in the control circuit. Therefore, if the gear grinding device according to the prior art is already prepared, the multi-gear grinding tool 42 can be applied in a short period of time and at low cost by modification.
[0091]
Further, the pulse doubling unit 109 may be provided outside the control circuit 100. In this case, the control circuit 100 can use the control circuit of the related art as it is.
[0092]
Further, in the method of automatically meshing the gear 22 to be ground and the gear grinding tool 42 and further grinding the gear 22 to be ground, a portion performed by an operator is basically the same as the method according to the related art. It is. Therefore, an operator operating the gear grinding device according to the related art can operate the gear grinding device 10 according to the present embodiment without requiring skill.
[0093]
In the counter memory circuit 118, each time the tooth of the gear 22 to be ground is detected, it is possible to confirm the coincidence of the phases, so that more accurate phase matching can be performed.
[0094]
Further, even when the number of spiral threads of the gear grinding tool 42 is one or three or more, the present invention can be applied by changing the value G of the dip switch 164 or the setting of the dip switch 182.
[0095]
The control circuit 100 may partially use a software function using a microcomputer or the like.
[0096]
The gear grinding device according to the present invention is not limited to the above-described embodiment, but can adopt various configurations without departing from the gist of the present invention.
[0097]
【The invention's effect】
As described above, according to the gear grinding device of the present invention, the automatic grinding of the gear grinding tool having a plurality of spiral threads and the gear to be ground is achieved, and the effect of reducing the cycle time of grinding is achieved. can do.
[0098]
Further, based on a conventional automatic meshing technique, that is, a gear grinding apparatus for automatically meshing with a gear to be ground using a gear grinding tool having one spiral thread, an A-phase signal and a Z-phase signal in a control circuit thereof are used. By adding a pulse doubling unit to the phase signal input processing unit, a plurality of gear grinding tools can be applied.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a gear grinding device according to the present embodiment.
FIG. 2 is a schematic explanatory view showing a positional relationship between a gear to be ground and a gear grinding tool.
FIG. 3 is a schematic structural explanatory view showing a connection state between a gear to be ground and a work spindle motor.
FIG. 4 is a block diagram of a control circuit that controls an automatic meshing operation.
FIG. 5 is a time chart showing the relationship among an A-phase signal, a Z-phase signal, a count signal, a Z-phase pulse doubling signal, a shaped pulse, an internal signal, and a coincidence signal.
FIG. 6 is a flowchart (part 1) illustrating a procedure of a phase teaching process and an automatic meshing operation.
FIG. 7 is a flowchart (part 2) illustrating a procedure of a phase teaching process and an automatic meshing operation.
FIG. 8 is a partially omitted block diagram according to a modified example of the control circuit that controls the automatic meshing operation.
FIG. 9 is a schematic explanatory view showing a state in which a gear to be ground is ground by a gear grinding tool having two spiral threads.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Gear grinding device 14 ... Cut table 16 ... Cut motor 18 ... Traverse table 20 ... Traverse motor 22 ... Grounding gear 24 ... Tooth tip detection sensor 26 ... Work spindle motor 42 ... Gear grinding tool 46,54 ... Pulse Generators 47a, 47b Spiral strip 51 Electromagnetic clutch 100 Control circuit 102 Input signal processing unit 104 Rotation control unit 106 Cutting mechanism control unit 108 Clutch control unit 109 Pulse doubling unit 110 Waveform shaping circuit 116 , 132, 160... Counter 118... Counter memory circuit 118 a... Storage unit 120... Index calculation circuit 122, 124, 136... AND gate 126, 162 OR gate 164, 182. Signal Eb: Z-phase signal Ec: Count signal Ed: Z-phase pulse multiplication signal Ee: Z-phase pulse multiplication signal N0: Number of stored phase pulses N1: Number of phase pulses P0: Shaped pulse w: Allowable width

Claims (3)

In a gear grinding apparatus for synchronously rotating a gear grinding tool having two or more spiral streaks and a gear to be ground, and grinding the gear to be ground while meshing the spiral streaks with the tooth grooves of the gear to be ground. ,
A pulse generator that detects a zero point position and a rotation change amount of the gear grinding tool, and outputs each as a pulse,
A tooth tip detection sensor that detects each tooth passing along with the rotation of the grinding gear and outputs the pulse as a pulse,
A pulse indicating the zero position output by the pulse generator is input, and a pulse doubling unit that outputs a pulse corresponding to the number of spiral streaks corresponding to the input pulse,
A counter that counts a pulse indicating the amount of rotation change of the gear grinding tool as the number of phase pulses between the timing at which the pulse doubling unit outputs a pulse and the timing at which the value of the pulse output from the tooth tip detection sensor switches. When,
When the phase of the gear to be ground and the phase of the gear grinding tool coincide, a storage unit that stores the number of phase pulses as the number of stored phase pulses,
A phase coincidence determining unit that determines whether the number of phase pulses newly counted by the counter matches the number of stored phase pulses, or
When the newly counted phase pulse number matches the stored phase pulse number, the grinding gear is rotated synchronously, and the newly counted phase pulse number does not match the stored phase pulse number. Sometimes a rotation control unit that asynchronously rotates the gear to be ground,
A gear grinding device comprising: The gear grinding device according to claim 1,
The pulse doubling unit counts a pulse indicating the rotation change amount, and the count value is a value obtained by dividing the number of pulses of the rotation change amount per rotation of the gear grinding tool by the number of the spiral streaks and the value. A gear grinding apparatus characterized in that a pulse is output each time an integer multiple is reached. The gear grinding device according to claim 1,
The gear grinding device according to claim 1, wherein the pulse doubling unit is a multiplier circuit that outputs a pulse having a frequency that is an integral multiple of a pulse frequency indicating the zero point position.

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