JP3800360B2 - Processing method of involute tooth profile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an involute tooth profile processing method, and more particularly to a processing method suitable for dressing a honing grindstone with a dress grindstone.
[0002]
Conventionally, a honing machine for honing a gear in a final process of machining a gear having a plurality of involute tooth shapes has a gear support mechanism that rotatably supports the gear, and an involute tooth shape that meshes with the gear. A grindstone support mechanism that rotatably supports a honing grindstone having a plurality of internal teeth, a mechanism that reciprocally moves the grindstone support mechanism in the axial direction of the gear, a mechanism that rotationally drives the grindstone, and a gear A mechanism for turning the grindstone to adjust the axis crossing angle, and a cutting feed mechanism for cutting and feeding the grindstone in a direction in which the distance between the center of the grindstone and the gear increases. When the tooth surface of the gear is honed, the honing is performed while repeating the cutting feed and the reciprocating traverse movement in the direction of the tooth trace while rotating the grindstone and the gear in a state where the grindstone is engaged with the gear. This type of gear honing machine is described in JP-A-6-1265 and JP-A-6-320335.
[0003]
By the way, since the grindstone wears while honing a plurality of gears with one honing grindstone, every time a predetermined number (for example, 20 to 30) gears are honed, the dressing Dress the grinding wheel for honing with a grinding wheel (dress gear). In this case, a dressing grindstone is attached to the honing machine in place of the gears, and the honing grinder and the dressing grindstone are rotated in a state of meshing pressure contact, and dressing is performed while repeating the infeed and reciprocating traverse movements. To do. This type of dressing technique is described in JP-A-6-320335.
[0004]
[Problems to be solved by the invention]
In the honing grindstone, although the tooth surface is regenerated by dressing, tooth wear is unavoidable, and the tooth height decreases during many honing operations. FIG. 7 is a view showing a state where the honing grindstone 100 and the dressing grindstone 101 are engaged with each other in a state where the honing grindstone 100 is hardly worn, and FIG. 8 is a state in which the honing grindstone 100 is significantly worn. It is the figure which showed the meshing state of the honing grindstone 100 and the dressing grindstone 101 in FIG. In the conventional dressing for the honing grindstone 100, regardless of the wear state of the honing grindstone 100, as shown in FIG. 7 and FIG. A method of adjusting the distance between the centers of both the grinding stones 100 and 101 so as to dress only the cutting depth A is employed.
[0005]
However, when dressing is performed from the state of FIG. 7 and dressing is performed by the cutting amount A up to the position indicated by the chain line a, the tooth surface 100a of the honing grindstone 100 is dressed to the position of the chain line b. Further, when dressing is performed from the state of FIG. 8 and dressing is performed by the cutting amount A up to the position indicated by the chain line a, the tooth surface 100b of the honing grindstone 100 is dressed to the position of the chain line c. Then, since the dress margin C from the tooth surface 100b to the chain line c is larger by several μm than the dress margin B from the tooth surface 100a to the chain line b, it is necessary to perform useless dressing, and the time required for the dress However, there is a problem that the operating rate of the honing process is reduced and the life of the expensive dressing grindstone is reduced.
An object of the present invention is to eliminate wasteful machining in an involute tooth profile machining method in which an external gear-like member and an internal gear-like member are engaged and rotated while one gear-like member is used to machine the other gear-like member. Thus, the processing efficiency is increased, the life of one gear-shaped member is extended, and the like.
[0006]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for processing an involute tooth profile, which rotatably supports an external gear-shaped member having a plurality of external teeth of an involute tooth profile, and a plurality of internal teeth of an involute tooth profile engaged with the external teeth of the gear-shaped member. The internal gear-like member is rotatably supported, and is driven to rotate in a state where both gear-like members are engaged while the external gear-like member and the internal gear-like member are moved relative to each other in the press-contacting direction by the cutting feed means. In the involute tooth profile processing method in which the tooth of the other gear-like member is machined by one gear-like member by being rotationally driven by means, one or more in the plurality of times of machining of the same kind of plural or the same other gear-like member When the distance between the centers of the two gear-like members varies due to the wear of the other gear-like member, the cutting feed amount by the cutting feed means is set small as the center-to-center distance increases. It is characterized in that.
[0007]
Here, when one gear-shaped member is an external gear-shaped member and the other gear-shaped member is an internal gear-shaped member, one gear-shaped member is an internal gear-shaped member, and the other gear And the case where the shaped member is an external gear-like member. The plurality of other gear-like members of the same type are, for example, a plurality of workpieces to be machined. In this case, one gear-like member is a machining tool. The same other gear-shaped member is, for example, a honing grindstone. In this case, one gear-shaped member is a dressing grindstone.
[0008]
When a plurality of times the same kind of plural or identical other gear-like members are processed, the distance between the centers of both gear-like members varies due to the consumption of one or the other gear-like member. That is, processing is performed by adjusting the distance between the centers of both gear-like members. In this case, the cutting feed amount by the cutting feed means is set to be small in accordance with the increase in the center-to-center distance (in accordance with the progress of wear of one or the other gear-like member).
[0009]
As described with reference to FIGS. 7 and 8 in the “Problem” section, when the infeed amount is set constant even when the distance between the centers of both gear-shaped members is increased, the characteristics of the involute tooth profile are set. Therefore, as the distance between the centers of both gear-shaped members increases, the machining allowance in the tooth thickness direction increases, and wasteful machining is performed. However, in the present invention, the cutting feed amount is set to be small as the distance between the centers is increased, so that useless machining can be reduced.
[0010]
According to a second aspect of the present invention, in the first aspect of the invention, the cutting feed amount by the cutting feeding means is set so that the machining allowance in the tooth thickness direction of the other gear-like member is constant over the plurality of machining operations. It is characterized by doing. Thus, in order to set the cutting feed amount so that the machining allowance in the tooth thickness direction of the other gear-shaped member is constant over the plurality of times of machining, it is possible to perform only the minimum necessary machining, Unnecessary processing can be eliminated, and the life of one gear-like member can be extended.
[0011]
The invention of claim 3 is the invention of claim 2, wherein the internal gear-shaped member is a honing grindstone, and the external gear-shaped member is a dressing grindstone for dressing the honing grindstone. It is what. By applying the present invention to the processing of the involute tooth profile when dressing the honing processing grindstone with the dressing grindstone, the tooth length of the honing processing grindstone decreases while being repeatedly dressed. The useless dress can be eliminated, the dressing time can be shortened, the operating rate of the honing process can be increased, and the life of the expensive dressing grindstone can be extended.
[0012]
The invention according to claim 4 is the invention according to claim 2, wherein the external gear-shaped member is a honing grindstone, and the internal gear-shaped member is a dressing grindstone for dressing the honing grindstone. It is what. Compared with the case of Claim 3, since the relationship between the external teeth and the internal teeth is only reversed, the same operations and effects as those of Claim 3 are basically obtained.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment is a dressing method in which a honing machine for honing an external gear is dressed with a grindstone for dressing (dress gear). It is an example at the time of applying this invention to.
First, a numerically controlled honing machine M will be described with reference to FIGS. As shown in FIG. 1, the honing machine M includes a grindstone support housing 10, and the grindstone support housing 10 is provided with a hollow ring portion 11. A ring sprocket 12 having outward teeth is rotatably held on the inner side in the radial direction of the ring portion 11 via a grinding wheel bearing (not shown). Honing is performed on the inner side in the radial direction of the ring sprocket 12 by a grindstone presser 13. A processing grindstone 14 (hereinafter referred to as a grindstone) is fixed.
[0014]
This grindstone 14 has a plurality of involute tooth shapes as shown in FIG. 4 and rotates integrally with the ring sprocket 12. A doughnut-shaped draining plate 15 is fixed. A grindstone drive motor 16 is fixed laterally on the upper portion of the grindstone support housing 10, and a motor sprocket 18 is fixed to an output shaft 17 of the grindstone drive motor 16. The motor sprocket 18 is connected to a ring sprocket via a silent chain 19. 12, the motor sprocket 18, the silent chain 19, and the ring sprocket 12 are configured to transmit the driving force of the grindstone drive motor 16 to the grindstone 14, and the motor output shaft 17 moves in the direction of arrow A1 in FIG. As the wheel rotates, the grindstone 14 rotates in the direction of arrow A2 in FIG.
[0015]
A flange portion 20 is provided at the rear portion of the grindstone support housing 10, and the flange portion 20 is fixed to the rotation output shaft 23 of the axis crossing angle adjusting device 22 by a bolt 21. The shaft crossing angle adjusting device 22 includes a grindstone turning motor 24 that rotationally drives the rotation output shaft 23, and a workpiece (external gear) or dressing grindstone 25 for honing processing by the rotational driving force of the grindstone turning motor 24. The overall inclination angle (axis crossing angle) of the grindstone 14 and the grindstone support housing 10 is adjusted. This axis crossing angle adjusting device 22 is fixed on a table 26, and this table 26 is slidably installed in a predetermined cutting direction (arrow A3 in FIG. 1) and the opposite direction. The table 26 is provided with a cutting drive motor 27 and a ball screw mechanism (not shown). By these operations, the entire crossing angle adjusting device 22, the grindstone support housing 10 and the grindstone 14 slide in the cutting direction together with the table 26. It is configured to be driven.
[0016]
In the case of this embodiment, the workpiece to be honed by the honing machine M is a helical gear having a plurality of external teeth of an involute tooth profile. Therefore, the grindstone 14 has a plurality of involute tooth profiles that can mesh with the workpiece. The dressing grindstone 25 that has internal teeth and dresses the grindstone 14 also has a plurality of involute tooth shapes that can mesh with the grindstone 14.
[0017]
The dressing grindstone 25 is rotatably supported by a work support mechanism 30 shown in FIG. The work support mechanism 30 includes a headstock 31 and a tailstock 32 for holding a work or dressing grindstone 25 in the axial direction. The head stock 31 rotatably supports a main shaft 33, and the main shaft 33 is rotationally driven by a main shaft motor 34. A pinching portion 35 is formed at the tip of the main shaft 33 so as to be in pressure contact with one end of the workpiece or dressing grindstone 25. The tailstock 32 is disposed on the upper surface of the bed 36, and supports the tailstock shaft 37 so as to be slidable in the arrow A4 direction (work axis direction) in FIG.
[0018]
This tailstock 32 is provided with a clamping portion 38 that is in pressure contact with the other axial end of the workpiece or dressing grindstone 25 via a thrust bearing, and the clamping portion 38 and the tailstock shaft 37 are connected to each other. Driven in the direction approaching the headstock 31 by the chuck motor 39, the workpiece or dressing grindstone 25 is sandwiched, and the rotational driving force transmitted to the spindle 33 is applied to the workpiece or dress via the frictional force from the sandwiching portion 35. It is transmitted to the grindstone 25. The main shaft 33 is driven to rotate only when the teeth of the work or dressing grindstone 25 are indexed to a predetermined position when the work or dressing grindstone 25 is engaged with the grindstone 14, and after the engagement, the main shaft 33 is divided by a clutch mechanism (not shown). The connection with the motor 34 is released, and the workpiece or dressing grindstone 25 rotates with the grindstone 14 in the direction of arrow A6 in FIG.
[0019]
The headstock 31 and the tailstock 32 are fixedly provided on a table 36 independent of the table 26. The table 36 is shown in FIG. 3 by a table drive motor 40 and a ball screw mechanism (not shown). The table 36 is configured to be reciprocally traversed in the axial direction of the dressing grindstone 25 when dressing the grindstone 14 with the dressing grindstone 25. . In addition, a displacement sensor 52 for detecting that the dressing grindstone 25 is engaged with the grindstone 14 in a state without backlash is provided at the tip of the tailstock shaft 37.
[0020]
Next, a control system of the honing machine M will be described.
As shown in FIG. 5, a control unit 50 for controlling a plurality of servo motors of the honing machine M by a numerical control method is provided. An operation panel 51 is connected to the control unit 50, and a displacement sensor 52 A detection signal is input, and the control unit 50 controls the grindstone drive motor 16, the grindstone turning motor 24, the cutting drive motor 27, the spindle motor 34, the chuck motor 39, the table drive motor 40, and the like. The control unit 50 includes an input / output interface, a computer, and a drive circuit for a plurality of motors. A control program for honing various workpieces (external gears) and various grindstones 14 are stored in the computer memory. A dress control program for dressing is input and stored in advance, and this dress control program includes a cutting control subroutine unique to the present invention, which will be described later, and various data input and stored in advance.
[0021]
The cutting control will be described. For example, every time a predetermined number of 20 to 30 workpieces are honed, dressing is performed on the grindstone 14 using the dressing grindstone 25. Since the grindstone 14 is consumed while the dress is repeated, the center distance S between the grindstone 14 and the dressing grindstone 25 (the distance between the points O1 and O2 in FIG. 4) increases.
As described with reference to FIGS. 7 and 8 in the prior art section, when the cutting amount is controlled so that the cutting amount is constant regardless of the wear or wear state of the grindstone 14, the grindstone 14 is controlled. As the amount of wear and the amount of wear increase, the cutting allowance in the tooth thickness direction of the grindstone 14 increases, resulting in unnecessary dressing.
Therefore, in the present invention, as shown in FIG. 6, the cutting distance α when the grindstone 14 is new and the center distance S is S0 is set to α0, and the center distance S increases due to wear and wear of the grindstone 14. Accordingly, the cutting amount α is set linearly so that the cutting allowance in the thickness direction of the involute teeth of the grindstone 14 is constant (for example, 15 μm). Then, with the inter-center distance S as a parameter, the cutting amount α is set to be α = −K (S−S0) + α0. Then, when the center distance S increases by ΔS from S0 due to wear or wear of the grindstone 14, it is assumed that the grindstone 14 is at the end of its life.
[0022]
The proportional constants K, S0, α0, and ΔS are obtained by experiments and theoretical calculations in advance for various types and sizes of the grindstone 14 and the dressing grindstone 25 and stored in a computer. For example, in the case of a grindstone 14 and a dressing grindstone 25 of a certain size, a target cutting amount 15 μm, S0 = 100 mm, ΔS = 10 mm, α0 = 50-60 μm, α1 = 30-40 μm, which is a cutting allowance in the tooth thickness direction Value. However, the values of α0, α1, and ΔS exemplified above can be applied to all types of grindstones 14 in common. However, ΔS decreases as the size of the grindstone 14 decreases. Here, the cutting amount of 15 μm is achieved by making a cutting of 2 μm for each traverse end and traversing as many times as necessary. It should be noted that although the accuracy of the cutting depth α can be ensured with sufficient accuracy even if it is set linearly, it can also be set to a characteristic of a quadratic curve.
[0023]
Next, a processing method for dressing the grindstone 14 using the dressing grindstone 25 by the honing machine M will be described.
When the grindstone 14 is dressed with the same dressing grindstone 25 every time a predetermined number of workpieces are honed, each dressing is performed as follows.
First, in the preparation stage, the grindstone 14 and the dressing grindstone 25 are set in the honing machine M in a state where the axes coincide with each other, the crossing angle is adjusted by the crossing angle adjusting device 22, and then the cutting drive is performed. The grindstone 14 is engaged with the dressing grindstone 25 through the movement of the table 26 driven by the motor 27, and then the dressing grindstone 25 is not backlashed to the grindstone 14 through the driving of the spindle motor 34 and the cutting drive motor 27. Engage with the state. At this time, when the tip of the tooth of the dressing grindstone 25 comes into contact with the bottom surface of the tooth groove of the grindstone 14, the detection signal of the displacement sensor 52 becomes equal to or greater than a predetermined value. Let
[0024]
The control unit 50 includes data on specifications of the grindstone 14 and the dressing grindstone 25, distance between centers S0 when the grindstone 14 is new, data on the proportional constants K, S0, α0, ΔS, α = −K ( An arithmetic expression of S−S0) + α0 is stored in advance. Then, the computer S of the control unit 50 calculates the distance S between the centers of the grindstone 14 and the dressing grindstone 25 from the driving amount of the cutting drive motor 27 after the point when the axes of the grindstone 14 and the dressing grindstone 25 are matched. By applying this center-to-center distance S to the arithmetic expression, the cutting depth α in the current dress is obtained.
[0025]
Here, the obtained cut amount α is distributed and given to a plurality of traverses. The traverse is an operation of reciprocating the table 36 by a predetermined stroke in the axial direction of the dressing grindstone 25 by the table driving motor 40. The traverse of the small dressing grindstone 25 having a diameter of about 5 cm as in the present embodiment. In some cases, for example, dressing through 12 traverses. Assuming that the divided cut amount Δα is given to each traverse end of the 12-time traverse, Δα = α / 24 from 12 × 2 × Δα = α.
[0026]
In this manner, the dressing of this time for the grindstone 14 is started after the division cutting amount Δα is obtained. The dressing process itself is the same as the normal dressing process. The grindstone drive motor 16 is driven to rotate the grindstone 14, the dressing grindstone 25 is driven to rotate, and the table drive motor 40 traverses the table 36. Dress up. Then, at each traverse end, the cutting drive motor 27 is driven for cutting by the divided cutting amount Δα, and the dressing is completed for a predetermined time.
[0027]
As described above, when the grindstone 14 is dressed a plurality of times, the center-to-center distance S increases according to the wear and wear of the grindstone 14, but the cutting allowance in the thickness direction of the involute teeth of the grindstone 14 in each dressing. Since the cutting amount α is decreased in accordance with the increase in the center-to-center distance S, the tooth surface of the involute tooth of the grindstone 14 is dressed by a certain minimum amount in each dressing. It is possible to eliminate unnecessary dresses and to shorten the dressing time, to greatly increase the efficiency of multiple times of dresses, and to suppress the wear of the expensive dressing grindstone 25 and extend its life. It is possible to increase the productivity of the honing process.
[0028]
In the above embodiment, the case where the honing grindstone 14 is dressed with the dressing grindstone 25 is described as an example, but the gear-shaped member having a plurality of involute tooth-shaped inner teeth is a gear-shaped member having a plurality of involute tooth-shaped outer teeth. The present invention can be similarly applied to shaving with a shaving cutter as a member, and a honing grindstone having a plurality of involute tooth external teeth is formed into a gear shape having a plurality of involute tooth internal teeth. The present invention can be similarly applied to dressing with a dressing grindstone as a member, and a shaving cutter which is a gear-like member having a plurality of involute tooth-shaped external teeth is a gear-like member having a plurality of involute tooth-shaped inner teeth. The present invention can be similarly applied to shaving.
[0029]
【The invention's effect】
According to the first aspect of the present invention, as described above, the involute is set by reducing the infeed amount by the infeed means in accordance with the increase in the center-to-center distance between one gear-like member and the other gear-like member. It is possible to reduce useless processing in processing the tooth profile.
According to the invention of claim 2, in addition to the same effect as that of claim 1, the cutting feed amount is set so that the machining allowance in the tooth thickness direction of the other gear-like member is constant over the plurality of times of machining. Since it is set, only the minimum necessary processing can be performed, wasteful processing can be eliminated, and the life of one gear-shaped member can be extended.
[0030]
According to the invention of claim 3, in addition to the same effect as that of claim 2, the dressing time can be shortened by eliminating unnecessary dresses, the operating rate of honing can be increased, and an expensive dress grindstone can be obtained. Life can be extended.
According to the invention of claim 4, in addition to the same effect as that of claim 2, the dressing time can be shortened by eliminating unnecessary dresses, the operating rate of honing can be increased, and an expensive dressing grindstone can be obtained. Life can be extended.
[Brief description of the drawings]
FIG. 1 is a front view of a main part of a honing machine according to an embodiment of the present invention.
FIG. 2 is a side view of the honing machine.
FIG. 3 is a side view of a workpiece support mechanism of the honing machine.
FIG. 4 is a cross-sectional view of a main part of a honing grindstone and a dress grindstone.
FIG. 5 is a block diagram of a control system of the honing machine.
FIG. 6 is a characteristic diagram of a cutting feed amount.
FIG. 7 is a cross-sectional view of a main part of a honing grindstone and a main part of a dressing grindstone according to the prior art.
FIG. 8 is a cross-sectional view of a main part of a honing grindstone and a main part of a dressing grindstone according to the prior art.
[Explanation of symbols]
M Honing Machine 14 Honing Wheel 16 Grinding Wheel Drive Motor 22 Axis Crossing Angle Adjustment Device 25 Dressing Wheel 30 Work Support Device

Claims (4)

An external gear-like member having a plurality of involute teeth is rotatably supported, and an internal gear-like member having a plurality of involute teeth is rotatably supported. One of the gear-like members is driven to rotate by the rotary drive means while the gear-like members are engaged with each other while the external gear-like member and the internal gear-like member are moved relative to each other in the pressure-contacting direction by the cutting feed means. In the involute tooth profile processing method for processing the teeth of the other gear-shaped member,
The center-to-center distance when the center-to-center distance of both gear-like members fluctuates due to wear of one or the other gear-like member in a plurality of operations on the same or other same gear-like member. The involute tooth profile machining method is characterized in that the cutting feed amount by the cutting feed means is set to a small value in accordance with the increase in. 2. The involute tooth profile according to claim 1, wherein a cutting feed amount by the cutting feed means is set so that a machining allowance in a tooth thickness direction of the other gear-shaped member is constant over the plurality of machining operations. Processing method. 3. The involute tooth profile processing method according to claim 2, wherein the internal gear-shaped member is a honing grindstone, and the external gear-shaped member is a dress grindstone for dressing the honing grindstone. 3. The involute tooth profile processing method according to claim 2, wherein the external gear-shaped member is a honing grindstone, and the internal gear-shaped member is a dress grindstone for dressing the honing grindstone.

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