JP3072693B2 - Gear shape measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of measuring a gear shape, and more particularly to a method of measuring a gear shape for detecting a shape error of a work while relatively meshing the work and a master gear for measuring a tooth profile. is there.

[0002]

2. Description of the Related Art Gears are an important component of machines that transmit motion through successive meshing teeth. In particular, since the rotary motion with an accurate speed ratio and large power can be transmitted efficiently with an extremely small structure, small gears such as instruments and watches, gears for medium-sized automobile transmissions, and large gears It is used in a very wide range of fields, down to tens of thousands of horsepower marine turbine reduction gears.

[0003] In general, the magnitude of vibration and noise of gears is affected by the quality of processing accuracy, and therefore, improvement of processing accuracy is desired. Particularly in recent years, in the field of automobiles where livability is regarded as important, improvement in machining accuracy of gears has been demanded in order to eliminate causes of generation of vibration and noise.

The gears are formed by a machining method using a gear cutting machine,
There are forging methods, electric discharge machining methods, and the like, but forging methods (extrusion forging and sintering forging) that can be mass-produced relatively easily at low cost in consideration of productivity are employed. In the case of forging, it is important to obtain a high-precision die because the accuracy of the die for forging directly affects the accuracy of the gear. This mold can be machined regardless of the mechanical strength of the material used as the mold material, and electric discharge machining capable of high-accuracy machining is used. After the metal mold formed by the electric discharge machining has been subjected to a grinding process or a lapping process, the gear shape is measured in order to confirm whether or not the mold is processed to a desired dimensional accuracy.

[0005] Conventional gear shape measuring methods are performed by a single-tooth surface meshing test, a double-tooth surface meshing test, or the like.

The single-tooth flank meshing test measures the advance / lag (angle transmission error) of the driven gear rotation angle when a predetermined backlash is applied to a pair of gears and the driving gear is rotated at low speed. In addition, in the both-tooth flank meshing test, a change in the center distance when the master gear and the measuring gear or the measuring gears are engaged with each other with no backlash and rotated is measured. From these, the gear shape such as runout, tooth thickness, flaw, etc. of the tooth space is measured.

[0007]

However, in the conventional method for measuring the gear shape, only the maximum value error with respect to the entire meshing portion of the gear can be detected. Therefore, when the tooth mold is partially corrected as in the case of a die, it is difficult to determine whether it is a machining error of the tooth profile or a corrected shape.

In a conventional method for measuring the shape of a gear using meshing, the other gear is driven by the rotational force of one gear (generally, the drive side is a work to be measured and the driven side is The measurement is performed by using a master gear for In this case, the force acting between the work and the master gear is determined by the biasing force that urges the work in the radial direction so that the master gear detects subtle errors in the work, and the force that causes the work to rotate the master gear following rotation. This is a pressing force for pressing the master gear in the circumferential direction. The urging force is a force necessary for accurate measurement of the gear shape, but the pressing force acts as a force that inhibits a delicate displacement of the master gear. Therefore, there has been a problem that the gear shape cannot be accurately measured by the conventional measuring method.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for measuring the shape of a gear which can eliminate unnecessary external force applied to the master gear and accurately measure the shape of the gear. .

It is another object of the present invention to provide a method of measuring a gear shape which can accurately measure a gear shape of a desired portion in a tooth trace direction of a work.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, first, the present invention ideally engages a gear-shaped workpiece rotatably supported with a shaft and a master gear for measuring a tooth profile. When the meshing motion is performed along the locus, the displacement of the master gear and the workpiece with respect to the ideal meshing locus is detected by a detection unit, and the shape error between the workpiece and the master gear is measured. Is what you do.

Second, in the first aspect, the displacement between the master gear and the workpiece with respect to the ideal meshing locus is a radial displacement of the gear-shaped workpiece. Thirdly, in the first aspect, the displacement amount between the master gear and the workpiece with respect to the ideal meshing locus is a displacement amount in the rotation direction of the gear-shaped workpiece.

Fourthly, a gear-shaped workpiece rotatably supported on a shaft and a master gear for measuring a tooth profile with a thin tooth trace are engaged with an ideal meshing locus to move. When the master gear is moved in the tooth trace direction of the work, the detection unit detects the displacement amount of the workpiece and the workpiece with respect to the ideal meshing locus, and detects a shape error between the workpiece and the workpiece master gear. It is characterized by measuring.

[0014]

In the method for measuring the gear shape according to the present invention, since the master gear for measuring the tooth profile and the work are engaged with each other in an ideal meshing locus, a circumferential direction acting between the master gear and the work is used. Can be eliminated. Therefore, it is possible to accurately detect a subtle displacement of the master gear due to a change in the shape of the workpiece by the detection unit.

The master gear having a thin tooth trace is engaged with the workpiece in an ideal meshing locus with the workpiece, and the ideal mesh is moved while moving the master gear in the tooth trace direction of the workpiece. The amount of displacement between the master gear and the workpiece with respect to the locus is detected by a detection unit. Therefore, it is possible to detect the tooth trace accuracy together with the gear shape accuracy.

[0016]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view of a measuring apparatus for performing the gear shape measuring method according to the present invention. The measuring device 1 shown in FIG. 1 is an automatic jig changing device 2 having a robot arm 2a.
(A measuring jig according to a desired gear shape) supplied by the above-described method is held by a holder 5 that is linked to an indexing rotary device 4 having an indexing position determining device. The holder 5 and the indexing rotary device 4 are built in a rotary head 7 that moves up and down along the column 6. The work 8 to be measured has a plurality of claws 9a and is fixed by a rotatable chuck 9 by a rotation mechanism (not shown) such as a servomotor.
The chuck 9 is a base 1 having a built-in chuck rotating mechanism.
0, and the base 10 is held by a saddle table 11 having a drive mechanism movable in the X-axis and Y-axis directions. The upper surface of the saddle table 11 is provided with an openable / closable cover 12 surrounding the work 8, the chuck 9, the base 10, and the like in order to equalize the measurement environment and ensure the safety of the operator. Further, a centralized control processing device 13 including a measurement result display section 13a is provided above the measuring device 1, and in addition, a drive control device for driving the measuring device 1 and the like are provided.

A method of measuring the shape of the internal gear by the measuring device 1 having the above-described configuration will be described with reference to FIGS.

The feature of the present invention resides in that the gear-shaped workpiece 8 rotatably supported by the shaft and the master gear 3a for measuring the tooth profile are engaged with each other in an ideal meshing locus so that the two can be moved together. In order to eliminate unnecessary external force to be applied and to perform a meshing movement on the ideal meshing trajectory at this time, a correction control amount and a shift amount of the total shape master gear 3a and the deviation of the total shape master gear 3a which are performed on the work 8 are set as displacement amounts And the shape error between the workpiece 8 and the master gear 3a is measured.

The workpiece 8 and the master gear 3a, which are rotated by the respective drive sources, perform synchronous movements as if the planetary and pinion gears of the planetary gear mechanism and the internal gears are moving. That is, the master gear 3a having a predetermined gear shape attached to the holder 5 at the center of the machine of the measuring device 1 is used for the workpiece 8 held by the plurality of claws 9a of the chuck 9 as shown in FIG.
The inner peripheral portion rotates in the drawing the arrow L ₁ direction. At this time, the full-form master gear 3a is arranged so as to urge the work 8 with a constant urging force in the radial direction in order to detect a subtle shape error of the work 8. On the other hand, the work 8 is the saddle table 1
Rotatably attached to the base 10 held in 1,
The rotation in FIG. 3 in the arrow L ₂ direction together form-master gear 3a. At this time, feedback control is performed on the chuck 9 holding the work 8 while monitoring the work 8 to follow the rotation speed of the master gear 3a by the chuck rotation position / rotation speed detection unit 14 provided inside the base 10. It is rotationally driven by a possible work rotation servomotor 15.

Therefore, the work 8 is formed into the master gear 3a.
And is controlled by separate drive sources so as to follow the master gear 3a.
The only force acting between them is the urging force by which the master gear 3a urges the work 8 in the radial direction (urges outward in FIG. 2) in order to detect a subtle shape error of the work 8. When the workpiece 8 is processed into a shape required by the overall master gear 3a, the overall master gear 3a and the workpiece 8 are processed.
The pressing force for pressing the tooth surfaces does not work between them, and the rotation speed and rotation speed of the workpiece master 8 are not corrected and controlled. A meshing motion is performed along the meshing locus.

If the workpiece 8 is not machined into the shape required by the master gear 3a,
Has a processing error, the work 8 performs the correction control so that the rotation speed of the work 8 matches the rotation speed of the master gear 3a, and the master gear 3a during the meshing movement.
Causes a shift in the rotation axis and rotation speed of the motor. This work 8
The control unit corrects the rotation speed of the workpiece 8 and detects a slight shift amount of the master gear 3a by a detection unit to calculate a shape error between the workpiece 8 and the master gear 3a.

FIGS. 4 to 7 show an example of the structure of the displacement detector of the measuring jig 3 having the above-mentioned master gear 3a.

FIG. 4 is a longitudinal sectional view of the measuring jig 3, wherein a case 30 integrated with or joined to the measuring jig 3 and a lid 31 thereof form a space 32. An Oldham coupling 34, which is built in the space 32 and fixed to the case 30, slides in only one direction. The Oldham coupling 34 is urged by a leaf spring 35 connected in a chasen shape around the circumference so as to always return to the center direction. Further, an Oldham coupling 36 that slides only in one direction perpendicular to the Oldham coupling 34 is disposed. The Oldham coupling 36
Similarly to the Oldham coupling 34, the plate spring 37 is urged so as to always return to the center direction by a leaf spring 37 connected in a whisk around the circumference. The combination of these Oldham couplings results in an Oldham coupling that can be moved in any direction. In addition, the Oldham coupling 36 includes a master gear 3a.
Holding shaft 38 is integrally or assembled and joined,
The washer 4 is attached to the holding shaft 38 via a positioning key 39.
The master gear 3a is fixed by the 0 and the bolt 41.

As shown in FIG. 5, small displacement detecting sensors 42 and 43 utilizing electric, magnetism, light and the like are provided on the outer peripheral portions of the Oldham couplings 34 and 36, respectively. As is apparent from the figure, the minute displacement amount detection sensors 42 and 43 have slidable sensor heads 42a and 43a, and detect the displacement amount of the sensor head based on the state where the Oldham couplings 34 and 36 are not displaced. And output. In FIG.
O Oldham coupling 34 is moved in the + Y direction center from O _0
1 shows a state in which the minute displacement amount detection sensor 42 detects the state of being displaced to ₁ , and a state in which the Oldham coupling 36 moves in the −X direction and the center is displaced from O ₀ to O ₂ by the minute displacement amount detection sensor 43. This shows the detection state. In this embodiment, an example is shown in which a small displacement amount detection sensor is arranged on one side of each Oldham's joint, but more accurate measurements are provided by providing the sensors on both sides and comparing and calculating the detection amounts of both opposing sides. be able to.

FIG. 6 shows an overall master gear 3a of the measuring jig 3.
FIG. 4 is a schematic diagram showing a state in which a workpiece 8 is displaced by the shape of a work 8.

[0027] If the workpiece 8 is finished within desired machining accuracy, when the workpiece 8 and Sokatachi master gear 3a has motion meshing, form-master gear 3a is had ideal mesh around the O ₀ locus Perform a meshing motion along. But,
If the workpiece 8 is finished outside the desired machining accuracy, the Oldham coupling incorporated in the measuring jig 3 is displaced as described above, and the master gear 3a is shifted from the ideal meshing motion, Δx, A meshing motion is performed around O ₁ and O ₂ shifted by Δy. The minute displacement amount detection sensors 42 and 43 detect the deviation between the actual meshing motion and the ideal meshing motion, and can calculate the gear shape by calculating. In FIG. 6, in order to accurately detect the radial shape error of the workpiece 8, the total shape master gear 3 is used.
A convex portion 3b is formed at the tooth tip portion of a, so that the convex portion 3b completely hits the tooth bottom portion 8a of the work 8.

FIG. 7 shows the circle of the workpiece 8 by cutting off the tooth tips of the master gear 3a so that the tooth tips of the master gear 3a do not hit the bottom 8a of the workpiece 8. A circumferential shape error is accurately detected. Even when the master gear 3a is displaced in this way, the work 8 corrects its own rotation speed in accordance with the rotation speed of the master gear 3a. Unnecessary external force does not act, and the shape error due to the displacement of the master gear 3a is accurately detected. The shape error of the gear at this time is indicated by the shape error detected by the displacement of the master gear 3a and the shape error calculated by the correction control of the rotation speed of the work 8.

By properly selecting the thickness of the master gear 3a in the tooth trace direction as a whole, the gear shape of the work 8 can be measured as required. That is, if the thickness in the tooth trace direction is increased, it is not possible to detect the shape error of the details of the work 8, but it is possible to measure the overall balance of the gear shape in the use state of the gear.

As shown in FIG. 8, the thickness of the master gear 3a in the form of a tooth is reduced in the direction of the tooth trace, and a measurement is made by the engagement movement of a very narrow area of the workpiece in the direction of the tooth trace, and the required requirements are determined. By successively feeding the master gear 3a of the general shape in the tooth trace direction by an arbitrary pitch that matches the precision, it is possible to detect the shape error of the details of the entire work. Therefore, it is possible to easily determine whether there is a machining error of the tooth profile or a corrected shape even when the tooth profile is partially corrected, such as a gear mold. Note that the shape of the master gear 3a as a whole is shown in FIG.
Shapes such as (a), (b) and (c) are possible,
The same effect can be obtained even if the shape is changed as required.

FIG. 9 shows another embodiment of the measuring jig 3.

An Oldham's joint 33 fixed to the case 30 inside a space 32 formed by the upper Oldham's joint part of the measuring jig 3, that is, the case 30 and its lid 31, a leaf spring 35 connected in a chasen shape, The configuration of the Oldham couplings 34, 36 and the like urged by 37 is the same as that of the measuring jig 3 shown in FIG. In this embodiment, a torsion bar 50 is provided to detect a minute displacement of the master gear 3a in the rotation direction. Lower Oldham's joints 51, 52, 53 and a lower case 54 are provided in order to suppress bending deformation of the torsion bar 50 whose rigidity has been reduced due to the provision of the torsion bar 50. The Oldham coupling 5
Like the upper Oldham couplings 34 and 36, the springs 2 and 53 are urged by leaf springs 55 and 56 connected in a whisk around the circumference so as to always return to the center. Further, the measuring jig 3 of the present embodiment is provided with a rotary encoder for detecting a minute rotational displacement of the master gear 3a. This rotary encoder is made of, for example, a semiconductor laser or the like, and a sensor head 57 having a light emitting / receiving section 57a is provided below the Oldham coupling 53, and a slit is formed in the slit for reading a movement angle between the light emitting / receiving sections 57a. 58 are arranged with a rotatable interval. The disk 58 is attached via a mount 59
When measuring the workpiece 8 with the master gear 3a while being fixed to the holding shaft 38 which rotates the master master gear 3a, in order to eliminate an error due to bending deformation, in cooperation with a retainer 60 which is separately mounted. The rotation of the holding shaft 38 is not hindered. According to the measuring jig 3, the accumulated pitch error and the adjacent pitch error can be measured by operating only the device that detects and outputs the minute displacement in the rotation direction.

FIG. 10 is a schematic diagram showing an example of a configuration for realizing the gear shape measuring method of the present invention. Measurement jig 3
(Including a minute displacement detection mechanism of a master gear (not shown)) is attached to the holder 5 and held by a rotary head unit 7 including a measuring jig rotating servomotor 71 having a rotation position / speed detection unit 70. I have. The rotary head 7 is driven vertically by a Z-direction feed mechanism. When the Z-direction feed mechanism is composed of, for example, a ball screw 72, the rotary head unit 7 fixed to the female screw portion 73 engages with the column 6 and has a rotary head driving servomotor 75 having a rotary head rotation position / speed detecting unit 74. The rotary head 7
It is driven with high precision in the direction (vertical direction in the figure). On the other hand, the work 8 is rotatably mounted on the base 10 and is held by a chuck 9 having a plurality of claws 9a. The work 8 has a chuck rotation speed detecting unit 14 and can perform feedback control while monitoring the rotation speed of the chuck 8. The rotation of the measuring jig 3 is synchronized with the rotation of the measuring jig 3 by the rotation servomotor 15 so as to rotate at a predetermined speed.

Further, the base 10 on which the chuck 9 is mounted
Are driven left and right by an X-direction feed mechanism. When the X-direction feed mechanism is composed of, for example, a ball screw 76, the base 10 fixed to the female screw portion 77 is engaged with the bed 78, and the base 10 is moved by a base driving servomotor 80 having a base rotational position / speed detecting portion 79. It is driven with high accuracy in the X direction (left and right directions in the figure). The saddle table 11 on which the base 10 is mounted is driven in the front-rear direction by a Y-direction feed mechanism. When the Y-direction feed mechanism is composed of, for example, a ball screw, the saddle table 11 fixed to the female screw portion 81 is provided with a saddle table rotation position / speed detector 82.
The saddle table 11 is driven with high accuracy in the Y direction (front-rear direction in the figure) by the saddle table driving servo motor 83 having Then, by combining the driving in the X direction and the driving in the Y direction, the position of the rotational movement of the work 8 can be freely changed.

The servo motors 15, 71, 8
0, 83, etc. are controlled by the NC controller 84 so that the related servo motors perform predetermined operations. In particular, at the time of measurement, the servo motor 71 for rotating the measuring jig that drives the master gear 3a by the NC controller 84 is used.
The work / rotation servomotor 15 which keeps the rotation speed of the work 8 precisely and performs the following operation is controlled by a position / speed control unit 85 which constantly detects the rotation position / rotation speed of the work 8 and feeds it back for comparison and control. Is controlled,
The gear shape is measured with high precision by a tooth profile error detector 86 that performs a rotation phase difference calculation and a radial displacement detection calculation of the measuring jig in conjunction with signals from the NC controller 84 and the position / speed controller 85. Further, the tooth profile error detecting section 86
The information indicating the numerical value and the position calculated in is displayed on the measurement result display section 13a.

[0036]

According to the method for measuring the gear shape according to the present invention, the master gear for measuring the tooth profile and the work are caused to mesh with each other in an ideal meshing locus, so that there is a gap between the master gear and the work. The working circumferential pressing force can be eliminated. Therefore, it is possible to accurately detect the subtle displacement of the overall master gear due to the change in the workpiece shape by the detection unit, and it is possible to perform stable measurement of the gear shape.

Further, the ideal master gear having a thin tooth trace direction is caused to mesh with a workpiece and the workpiece along an ideal mesh locus, and the ideal mesh is formed while moving the master gear in the tooth trace direction of the workpiece. The amount of displacement between the master gear and the workpiece with respect to the locus is detected by a detection unit. Therefore, it is possible to detect the tooth trace accuracy together with the gear shape accuracy, and to obtain a highly accurate gear shape.

[Brief description of the drawings]

FIG. 1 is a schematic view of a measuring device for performing a gear shape measuring method according to the present invention.

FIG. 2 is a side sectional view for explaining a positional relationship between a workpiece and an overall master gear in the gear shape measuring method according to the present invention.

FIG. 3 is an explanatory diagram for explaining a positional relationship between a workpiece and an overall master gear in the gear shape processing method according to the present invention.

FIG. 4 is a cross-sectional view of a measuring jig of the gear shape measuring method according to the present invention.

FIG. 5 is an explanatory diagram illustrating an attached state of a minute displacement amount detection sensor of a measuring jig in the gear shape measuring method according to the present invention.

FIG. 6 is an explanatory diagram for explaining a meshing state between a workpiece and a master gear of a gear shape measuring method according to the present invention.

FIG. 7 is an explanatory diagram for explaining a meshing state between a workpiece and a master gear having another shape in the method for measuring a gear shape according to the present invention.

FIG. 8 is an explanatory view showing a tooth tip shape of a master gear in a gear shape measuring method according to the present invention.

FIG. 9 is a sectional view of another measuring jig for measuring the shape of the gear according to the present invention.

FIG. 10 is an explanatory diagram illustrating a configuration for realizing a meshing motion along an ideal meshing locus in the gear shape measuring method according to the present invention.

[Explanation of symbols]

 3 Measurement jig 3a Form master gear 5 Holder 8 Work 9 Chuck 10 Base 11 Saddle table 14 Rotational position / rotation speed detector 15 Servo motor for work rotation

Claims (4)

(57) [Claims] When a gear-shaped workpiece rotatably supported by a gear and a master gear for measuring a tooth profile are meshed with an ideal meshing locus, the master gear for the ideal meshing locus is moved. A shape error between the workpiece and the master gear is measured by detecting a displacement amount of the workpiece and a workpiece by a detection unit. 2. The gear shape measuring method according to claim 1, wherein a displacement amount between the master gear and the workpiece with respect to the ideal meshing locus is a radial displacement amount of the gear-shaped workpiece. Method for measuring the gear shape. 3. The gear shape measuring method according to claim 1, wherein a displacement amount between the master gear and the workpiece with respect to the ideal meshing locus is a displacement amount in a rotation direction of the gear-shaped workpiece. Method for measuring the gear shape. 4. A gear-shaped workpiece rotatably supported by a shaft and a master gear for measuring a tooth profile with a thin tooth trace direction are caused to mesh with each other in an ideal meshing locus, and the master gear is moved by the gear. When moved in the direction of the tooth trace of the work,
A method for measuring the shape of a gear, comprising: detecting a displacement amount of a workpiece and a master gear with respect to the ideal meshing locus by a detection unit; and measuring a shape error between the workpiece and the master gear.