JPH02218533A - Bias grinding for helical gear with numerically-controlled gear grinding machine - Google Patents

Abstract

PURPOSE:To grind so that a tooth profile error diagram in a facewidth direction becomes unequal by conducting curve interpolation operation by adjusting a pulse signals given to a servo motor making a rotation axis rotate swingingly and another servo motor making a sliding base reciprocate linearly. CONSTITUTION:A pulse signal is given to the first servo motor 7, driving a ground gear 1 normal and reverse rotary motion with a rotation axis (said as 'A axis') 4 as the center, and the second servo motor 9 driving the feeding screw (said as 'Z axis') making a sliding base 3 reciprocating drive respectively. And the curve interpolation operation of a circular arc is conducted instead of the linear interpolation operation making the stroke St of the Z axis and the rotation angle theta of the A axis a direct proportional relation. The tooth profile error diagram (a), obtained from the error of an shaved off area of a tooth surface to an ideal tooth surface due to the curve interpolation operation shows the addendum descent condition of an A - A part, and a diagram c shows the addendum ascent condition of an C - C part. A tooth profile error occurred in a face width direction can be corrected by the curve interpolation operation, and a tooth surface having a small deviation from the logical tooth surface can be ground.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a method for bias-grinding helical gears by synchronously operating two-axis servo motors using an NC gear grinding machine. Regarding.

(Conventional technology) Gears usually have a module M1 pressure angle PA.

It can be expressed by the helix angle HA, the number of teeth Z, etc.

Then, pitch circle radius rP (= 0.5 part MXZ/C
o5 (HA)), and draw a grinding wheel 2 rotating at high speed in the tooth groove of the gear to be ground 1 as shown in Figs. 10 and 11. −θ
The south face of the involute can be ground by moving with the relationship xrP'. However, in the case of a spur gear, the setting angle of the grindstone must be changed to PA-)PA' using the relationship rP' of J2-PA'-cos-1(xcos(PA)). In the case of helical gears, the front pressure angle PS is introduced instead of PA of the spur gear p PS' - cosJ (7'V5'7x cos(PS
)), it is necessary to change it to ps-+ps'.

Tatashi p3. jan-1(tan(PA)/cos
(HA)). Here, St: Stroke (am) θ: Swing angle (RADIAN) rp': 3039 circle radius. FIG. 10 shows the grinding start position, FIG. 11 shows the grinding end position, and FIG. 13 is a graph showing the relationship between the stroke St and the swing angle (rotation angle) θ. If the movement is performed in accordance with the above relational expression and indexing is performed at a position where there is no interference between the gear to be ground 1 and the grindstone 2, the tooth surface can be continuously ground. Mark gear grinding machine,
Karlfurt's gear grinding machines are basically based on this principle.

An outline of a conventional grinding machine will be explained with reference to FIG. 23.

1 is a gear to be ground, 11 is a slide, 12 is a rotating shaft supported by the slide 11, 13 is a rolling disk corresponding to the rolling circle of the gear to be ground 1 fixed to the rotating shaft 12, and 14 is a rolling circle. Steel belt wrapped around plate 13 and fixed at both ends, 1
5 is a link mechanism that causes the slide 11 to reciprocate. This structure realizes a directly proportional relationship between the linear reciprocating motion and the oscillating rotational motion of the gear to be ground 1 by using the O-gully disk 13, the steel belt 14, and the like.

When grinding spur gears with such a grinder,
The plane created by the rotation of the grindstone and the tooth to be ground I11
The contact line 20 is parallel to the gear axis as shown in Fig. 24, and its length is almost constant over the entire tooth surface, so there is no problem, but when grinding a helical gear with a helical angle. has the following problems:

That is, as can be seen from FIG. 25, the contact 11123 (
Since the quality of each tooth surface (simultaneous engagement line) differs from one tooth surface to another, it is difficult to obtain a grinding result that matches the theoretical value using the grinding method of the prior art. The reason for this is that the difference in the length of the contact line 23 causes a slight difference in the grinding resistance by the grindstone, resulting in minute displacement of the grindstone and the machine body. In other words, there is a tendency for the grindstone to scrape off a little more of the tooth surface portion where the grinding resistance is low.

Therefore, if the grinding machine is set correctly, the tooth profile error diagram at the center of the tooth width 24 of the gear to be ground [section 13-B in FIG. Even if the tooth profile in that part is accurate, the A-A part in FIG. 25, which is near both ends of the face width 24,
The tooth profile error diagrams for the C-0 section are as shown in FIG. 26. This is because the contact line at the root of the tooth is short in the A-A section, so the meat at the root of the tooth is scraped off excessively.
On the other hand, in the C-0 section, the contact line at the tooth tip is short, which indicates that the meat at the tooth tip has been ground down excessively. This tendency of the grindstone to scrape off is particularly noticeable when it comes to materials that are difficult to grind.

Due to the above-mentioned problems, in the conventional technology, the second
As shown in FIG. 7, the gaps t, t2. We are trying to solve this problem by inserting an appropriate shim at t3 and mounting the rolling disk 13 intentionally eccentrically with respect to the rotating shaft 12 (the center 25 of the gear to be ground 1). This corresponds to changing the turning angle for a constant stroke.

This method is called the conventional bias grinding method, but it requires a complicated process of preparing a large number of shims with different dimensions and replacing them in appropriate combinations, so it is not possible to accurately modify the tooth profile. It's difficult for me.

(Problems to be Solved by the Invention) An object of the present invention is to obtain a bias grinding method that solves the problems of the prior art.

[Structure of the invention]

(Means for Solving the Problems) The bias grinding method of the present invention has the following configuration in order to achieve the above object.

A gear to be ground is fixed to a rotating shaft supported by a slide, and the rotating shaft is oscillated and rotated by a first servo motor through a gear mechanism, and the slide is driven by a second servo motor via a feed screw. In the method of grinding the gear to be ground by a grindstone, the gear to be ground is caused to make a linear reciprocating motion by a motor, and a proportional relationship is formed between the rotation angle and the stroke of the gear to be ground by synchronized operation of both the servo motors. Curve interpolation operation is performed by appropriately adjusting the pulse signals given to the servo motor and the second servo motor, respectively.
A combination of curve interpolation and linear interpolation is performed to grind the gear to be ground so that the tooth profile error diagram in the width direction of the gear to be ground is unequal.

Further, in the grinding method using a grindstone, a curve interpolation operation or a combination of curve interpolation and linear interpolation is performed to eliminate tooth profile errors that occur in the tooth width direction of the gear to be ground due to the linear interpolation operation.

Further, the motion relationship between the oscillating rotational motion of the gear to be ground by the first servo motor and the linear reciprocating motion of the gear to be ground by the second servo motor is a linear interpolation operation represented by an ideal straight line of St-θ. By interpolating a curve represented by a circular arc, making the circular arc convex upwardly or convex downwardly, and adjusting the radius of the circular arc, the discrepancy in the tooth profile error diagram in the face width direction can be reduced. The gear to be ground is ground to varying degrees.

(Function) A gear to be ground is fixed to a rotating shaft supported by a slide, and the rotating shaft is oscillated and rotated by a first servo motor via a gear mechanism, and the slide is rotated via a feed screw. When performing linear motion using the second servo motor, appropriate pulse signals are given to both servo motors to cause them to operate synchronously, creating a special relationship between the rotation angle of the gear to be ground and the stroke, which is different from the normal direct proportional relationship. A curve interpolation operation or a combination operation of curve interpolation and linear interpolation is performed so as to form a curved line.

By changing the shape of the curve or the combination of a curve and a straight line in the interpolation operation, the tooth profile error diagram in the face width direction of the gear to be ground becomes uneven, or the tooth profile error in the face width direction is eliminated. be able to.

Further, the motion relationship between the oscillating rotational motion of the gear to be ground by the first servo motor and the linear reciprocating motion of the gear to be ground by the second servo motor is a circular interpolation operation, and the arc is convex upward or convex downward. If the radius of the circular arc is adjusted to a larger or smaller radius, the degree of discrepancy in the tooth profile error diagram in the tooth width direction changes in various ways.

Therefore, by appropriately combining various arc shapes and radii, gears with various tooth profile curves in the face width direction can be formed.

(Example) FIG. 1 shows an example of a grinding machine of an NC processing machine that performs the bias grinding method of the present invention.

1 is a gear to be ground consisting of a helical gear, 2 is a grinding wheel, 3 is a slide, and 4 is a rotating shaft (rA axis) supported by the slide 3.
], 7 is a first servo motor that drives the gear to be ground in forward and reverse rotation via a reducer 15.6, 8 is a feed screw (referred to as rZ axis J) that reciprocates the slide 3, and 9 is a feed screw. This is the second servo motor that drives 8.

In such a grinding machine, a pulse signal is applied to each of the first servo motor 7 and the second servo motor 9,
13th between the stroke St of the Z axis and the rotation angle θ of the A axis
If you move it so that it forms a direct proportional relationship as shown in the figure,
Since the lengths of the contact lines 23 of the gear to be ground 1 are different as shown in FIG. 25, the grinding resistance acting on the grindstone 2 is different, and the tendency for the meat to be scraped off is different in each part of the south face of the gear to be ground 1. As a result, the grinding result is such that tooth profile error curves 8-A, BB, and CC are drawn as shown in FIG. 26, and the tooth profile is not as accurate as the theory.

By the way, as can be seen from FIG. 25, the grinding start phases of the end A-A section, the center B section B section, and the other end C-C section are slightly shifted in the direction of the tooth width 24. As can be seen from FIG. 2, the phase shift described above can be easily calculated by 81 from the specifications of the bevel gear, given the position in the face width direction. In addition, in the figure, the lengths of A-A, B-8, and C-C indicate the phase in which each part is ground, and A
The south face is ground from the root to the tip as linear reciprocating motion and rocking rotation are performed from the -A section to the B-B section and then to the C-0 section.

Therefore, in the present invention, the Z-axis stroke St,! :
An operation in which the rotation angle θ of the A-axis is directly proportional to the rotation angle θ, that is, a linear interpolation operation is not performed, but a circular arc curve interpolation operation as shown in FIG. 3 is performed.

Now, the curve interpolation operation shown in FIG. 3 is broken down into sections A-A, B-B and C-0, respectively, and graphs a, b and C in FIG. 4 are drawn. Normally, the error of the tooth profile error curve is defined as the relative deviation from the theoretical straight line showing a directly proportional relationship in the St-θ relationship graph. and δC.

The error in the Naori-B portion can be expressed as a relatively small δB from the shape of the curve in this portion.

In each of the figures a, b, and c, the hatched area indicates that the tooth surface is shaved away from the ideal tooth surface by the curve interpolation operation as described above. If these errors are rewritten in a manner similar to Figure 26, a and b in Figure 5
A tooth profile error diagram such as and C is obtained. In the same figure, a indicates a downward state of the tooth tip of the Δ-A section, and C indicates an upward state of the tooth tip of the C-0 section.

These a, b, and c of FIG. 5 are a, b of FIG. 26.

Comparing C with C, the tooth profile error that occurs in the tooth width direction due to the difference in grinding resistance during linear interpolation operation is corrected by the above-mentioned curved interpolation operation according to the present invention, resulting in small or no deviation from the theoretical tooth surface. It can be seen that the tooth flank can be ground.

Note that Fig. 5 shows that the tooth profile error diagram becomes slightly concave, but this is because the shape of the effective grinding surface of the grinding wheel 2 is slightly concave as shown in Fig. 6. shape 10
This can be easily solved by forming

In the description of the above embodiment, linear interpolation is converted into circular interpolation by I! However, by replacing this with a curve interpolation other than a circular arc or a combination of linear interpolation and curve interpolation, the tooth profiles of the A-A section, B-8WJ and C-0 section were intentionally made to be different. This tooth profile can be used as the tooth profile of a shaving cutter to transfer it to the tooth surface of a gear to be ground using the plunge cutting method, or other gears that mesh under various loads. To ensure that the tooth surfaces of the gears used for each gear are adapted to the loading conditions and exhibit high performance (in the tooth width direction, etc.), the tooth profile error diagram is made to be unequal in the tooth width direction. It can also be ground.

In addition, in the above embodiment, the center of the arc of circular interpolation is St-
Although it is taken above the ideal straight line of θ, it can also be taken below as shown in FIG.

Furthermore, in Fig. 7, the origin is 01, the end point of linear interpolation is Pl, and the pixel points are connected by a circular arc, but the position selection of the two points is not limited to this, and can be done as shown in Fig. 8. The origin 01 is set at (this means that the starting point of the stroke St is set at a negative position with respect to the rotation angle θ)
, curve interpolation operation can also be performed. In this way, the shapes of the errors in the A-A section, B-B section, and C-0 section can be changed as shown in Figure 9 a, b, and c, so the resulting gear The tooth flanks can be given a shape different from the embodiments described above.

Next, the bias grinding method of the present invention will be explained based on a block diagram, grinding data, etc. The specifications of the helical gear to be machined are as follows.

Module M5 Pressure angle PA 20° helix angle HA 15° right helix tooth
Number 2 36 teeth Width
B 30 tooth tip circle radius r, 9
8.5 Bidge circle radius rp93.175 mtai circle radius r, 87.190 Figure 14 shows how the first servo motor (driving the A-axis) and the second servo motor (driving the Z-axis) are driven by the method of the present invention. FIG. 15 is a block diagram for inputting predetermined pulses to each of the input terminals (FIG. 15), and FIG. 15 shows a calculation flow performed by a computer.

The rotary encoder attached to the A-axis drive servo motor of the NC gear grinding machine manufactured by our company generates 12,000 pulses per revolution,
The speed reduction mechanism is designed so that the pulse corresponds to a rotation angle of 1 second at the final stage. In addition, the rotary encoder attached to the servo motor of the two-axis drive generates 10,000 pulses per rotation, and the drive system in the middle is designed so that one pulse corresponds to 0.2μ of the movement of the Z@slide. has been done.

First, the basic specifications of the workpiece are input and IFL calculations are performed. Next, enter the DK (outer diameter), DP' (rolling circle), and Crt (minimum diameter required for grinding) to determine the required stroke lfi3tmax of the Z axis and the required rotation angle θ■aX of the A axis.
Perform the gI calculation. Since S t lax and θlaX have different symmetries, in order to simplify the 1st calculation, all 4 bias calculations are pulsed after converting to the number of pulses based on the design fixed value mentioned above! ll! Let's do it according to standards. By adding various quantities related to the grinding conditions (number of grinding times, depth of cut, feed rate, etc.) to this, an NC program is automatically created and transferred to the NC system.

When you confirm that the setting of the grindstone, workpiece, etc. is complete and press the start button, the NC device interprets the NC program and distributes each movement into pulses and sends them to the hex/Z-axis servo drivers. Therefore, it is impossible to perform synchronized operation of both axes based on rationality.

Next, grinding data when the bias grinding method according to the present invention is applied to 5KD11, which is a relatively soft material, will be explained.

This is an experimental example of grinding a right-handed gear as shown in Fig. 16. In this case, the grinding was performed from ■-■ section (A-A section) to ■-■ section (B-B section), then ■- Grinding progresses to part (C-C). Type 1 is when the center of the arc of circular interpolation is above the ideal line of St-θ,
Type 2 is a case where the center of the groove is below the ideal straight line of St-θ.

FIG. 17 shows the case where 3 was ground along the ideal straight line of 10. Soft material 5KD has small tooth profile error.
11 was used, and if a hard material is used, the resistance of the gear to be ground against the grindstone increases, and the tooth profile error also increases.

Figures 18 to 21 show experimental examples in which grinding was performed using Type 1 or Type 2, in which the stroke St of the reciprocating linear motion was 0.2 microns per pulse, and the rotation angle θ of the oscillating rotation motion was Each pulse is 1 second, and the number of pulses represents the total number of pulses from the start of grinding to the completion of grinding on one side of one tooth.

The bias machining radius R is also expressed by the number of pulses. The figure is horizontal @
(tooth width) is drawn at 5x magnification, and K1 (error) is drawn at 1000x magnification.

Comparing Fig. 19 and Fig. 21 of type 1, it is clear that the tooth profile 24 difference line diagram changes by adjusting the dimension of the bias machining radius R, and the dimension of this R is selected to be an appropriate size. By performing the grinding process, St-θ
It is possible to correct tooth profile errors that would occur by performing grinding using the ideal straight line, and to grind to an ideal tooth profile.

In addition, Type 2 in Figures 18 and 20 are also similar to Type 1.
Similarly, the tooth profile error changes depending on the dimensions of the bias machining half scale R. By selecting the dimension of this R to an appropriate size and performing the grinding process, it is possible to variously change the uneven ω of the tooth profile error diagram in the face width direction of the gear to be ground, and the required error can be adjusted. It is possible to obtain a grinding gear according to its intended use.

FIG. 22 shows details of a specific processing example of type 1.

Figures 17 to 21 are data from a qualitative experiment of "bias grinding" given an appropriate 1 ma.
FIG. 22 shows an example of processing with a specific bias applied. The center of R is set at the upper part of the ideal straight line of St-〇 (equivalent to type 1), and the end part is machined with a target value of 14μ of tooth tip descent. There are still some parts left uncut, but the 16th
The part corresponding to 1-1 in the figure is about 10μ down the tooth tip in the tooth profile error diagram L1-1 in Figure 22, and the part corresponding to 3--3 in Figure 16 is the tooth profile error diagram in Figure 22 and 1-9. It is. This is about 10μ
This corresponds to the tip of the tooth rising.

〔Effect of the invention〕

A gear to be ground is fixed to a rotating shaft supported by a slide, and the rotating shaft is oscillated and rotated by a first servo motor through a gear mechanism, and the slide is driven by a second servo motor via a feed screw. When grinding the gear to be ground with a grindstone by causing a linear reciprocating motion by a motor and forming a proportional relationship between the rotation angle and the stroke of the gear to be ground by synchronized operation of the two shafts, By applying appropriate pulse signals to the first servo motor and the second servo motor to perform curved interpolation operation, or by performing a combined operation of curved interpolation and linear interpolation, the teeth of the gear to be ground are adjusted. It is possible to form a tooth profile such that the tooth profile error diagram in the width direction is uneven.

In addition, by appropriately selecting the shape of the curve or the combination of a curve and a straight line in the interpolation operation, the tooth profile error in the tooth width direction of the gear to be ground caused by the linear interpolation operation can be eliminated, and the tooth 1t of the ideal tooth profile can be achieved. can be obtained.

Further, the relationship Wt between the oscillating rotational motion of the gear to be ground by the first servo motor and the linear reciprocating motion of the gear to be ground by the second servo motor is set to circular interpolation operation, and the arc is convex upward or convex downward. By adjusting the radius of the circular arc to be large or small, the degree of discrepancy in the tooth profile error diagram in the tooth width direction changes in various ways, so by appropriately combining these shapes and radii, Gears with various tooth profile curves in the width direction can be obtained depending on the purpose of use.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an overview of the Hasuba@@ grinding machine used in the grinding method of the present invention, Fig. 2 (2) 0 is an explanatory diagram regarding the method of the present invention, and Fig. 3 An explanatory diagram of circular interpolation operation, which is an example of the method, Fig. 4 @ (c)
is an explanatory diagram showing an exploded view of FIG. 3, FIG. One embodiment of the grindstone used in the method, FIG. 7 is an explanatory diagram of circular interpolation operation which is another embodiment of the method of the present invention, and FIG. 8 is yet another embodiment of the method of the present invention. Explanatory diagram for circular interpolation operation, No. 9
Figure (2) U (C) is an explanatory diagram showing an exploded view of Figure 8;
Figures 10 to 12 are explanatory diagrams of the method of grinding involute gears, with Figure 10 being the grinding start position, Figure 11 being the grinding end position, and Figure 12 being the position where indexing to the next tooth is possible. , Fig. 13 is an explanatory diagram of the linear interpolation operation used in the conventional grinding method for helical gears, Fig. 14 is a block diagram of the gear grinding machine operation used in the method of the present invention, and Fig. 15 is a computer-based calculation. Fig. 16 is a gear specification and explanatory diagram for understanding experimental examples using grinding data, and Fig. 17 is an experimental example of a tooth profile error diagram when a helical gear is ground by linear interpolation operation. , Figures 18 to 2
Figure 2 shows an experimental example of the tooth profile error ta diagram when a helical gear is ground by curve interpolation operation using the method of the present invention, and Figure 23 shows an example of a conventional gear grinding machine used for grinding a helical gear. A schematic perspective view, Fig. 24 is an explanatory diagram of the spur gear grinding method, Fig. 2
Figure 5 @(c) is an explanatory diagram of the grinding method for helical gears, No. 26
The figure is a tooth profile error diagram of a helical gear ground by the conventional technique, and FIG. 27 is an explanatory diagram of the conventional grinding method. 1. Gear to be ground, 2. Grinding wheel, 3. Slide, 4. Rotating shaft, 5.6. Worm type reduction mechanism, 7. First servo motor, 8. Feed screw, 9 ...Second servo motor. →θ O! 10 → 0 R=0 (direct proportional ze9 plus two) R= 64499536zf full-type 2R=644
9'? ! x36/iLsu';Z ia°1R==,9
Kuku 2646.3ha”) L7X-Type 2Xfαη ZeR=9 Kuku 2646 (3/Zurusu type! 1su L4 effect ≧) C-C Order δm Order 2′) Crime

Claims (3)

[Claims] (1) Fix the gear to be ground to the rotating shaft supported by the slide,
The rotary shaft is caused to swing and rotate by a first servo motor via a gear mechanism, and the slide is caused to move linearly and reciprocally by a second servo motor via a feed screw, and both servo motors are operated in synchronization. In the method of grinding the gear to be ground with a grindstone by forming a proportional relationship between the rotation angle and the stroke of the gear to be ground, the pulse signals respectively given to the first servo motor and the second servo motor are By making appropriate adjustments, a curve interpolation operation or a combined operation of curve interpolation and linear interpolation is performed, and the gear to be ground is ground so that the tooth profile error diagram in the face width direction is unequal. Bias grinding method for helical gears using an NC gear grinder. (2) The bias according to claim 1, wherein a curve interpolation operation or a combination of curve interpolation and linear interpolation operation is performed to eliminate tooth profile errors that occur in the face width direction of the gear to be ground due to the linear interpolation operation. Grinding method. (3) The motion relationship between the oscillating rotational motion of the gear to be ground by the first servo motor and the linear reciprocating motion of the gear to be ground by the second servo motor is defined as linear interpolation operation expressed by the ideal straight line of St-θ. By performing curve interpolation operation represented by a circular arc, making the circular arc convex upward or convex downward, and adjusting the radius of the circular arc, the tooth profile error line in the tooth width direction can be adjusted. 3. The bias grinding method according to claim 1, wherein the gear to be ground is ground to vary the degree of disparity in the drawings depending on the purpose of use.