JP2000271844A - Grinding method for half-toroidal cvt disk traction surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding method for a halh-toroidal CVT disk in which a grinding is performed within a range of appropriate main spindle swing angle with a grinding wheel diameter formed larger than specified. SOLUTION: A holding mechanism 22 for holding a work 28 and a working mechanism 21 having a tool 26 are provided. When a grinding work is performed by a grinding machine 20 in which either of the work 28 and the tool 26 is inclinable with respect to the other, a cutting edge angle/swing angle of the tool 26 is set properly with respect to a axis of the work 28, and a diameter of the tool 26 is determined based on an interference grinding wheel diameter calculated according to the work shape or the swing angle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for grinding a traction surface of a half toroidal type CVT disk.

[0002]

2. Description of the Related Art In recent years, the traction surface of a half toroidal CVT disk used as a continuously variable transmission of an automobile has been ground by a grinding machine.

[0003] Grinding performed by this grinder is performed in a plain type cylindrical grinder or an angular grinder type, and in a plain type grinder, the swing angle θ ₁ is 90 °.
The swing angle θ ₁ is 6 in the degree and angular type grinding machines.
It is 0 degrees, and the whetstone attached to the rotation axis of the grinding machine is in the direction perpendicular to the rotation axis of this whetstone (θ ₁ = 90 degrees)
Or a predetermined angle (θ ₁ = 60 degrees).

In a grinding machine, a work to be ground is held on an XY table. The XY table has a function of an X table for sliding the work in the X direction and a function of a Y table for sliding the work in the Y direction. X
The direction is a slide direction in the radial direction of the work, and the Y direction is a slide direction in the direction of the rotation axis of the work.

The functions of the X table and the Y table are as follows.
In order to cause both to act on the upper surface of the XY table, the components required to perform the respective functions are laminated in two layers, and are respectively superimposed on the spindle on the XY table side.

As a table other than the XY table, a grinding machine having a revolving table slidable in a direction perpendicular to the cutting direction of the grindstone is used as a table for holding a work. (JP-A-11-226870).

[0007]

However, in the above-described grinding machine, there is a problem that the actual allowance does not match the apparent allowance. Further, the problem of the grinding wheel interference diameter arises. That is, as shown in FIG. 2, when the grindstone 26 is in contact with the ground surface of the workpiece 28, the apparent allowance dimension is t '(the outer allowance dimension is t'). Between the wheel and the traction surface at the time of completion.
At the time of outside contact, t = t '× cos (θ ₁ + ω1) Expression 1 Here, θ _{1 is the} main shaft swing angle (the angle between the direction along the cutting direction of the grindstone 26 and the direction parallel to the mounting surface of the workpiece 28). ) Ω1: Arcsin ((φ−pcd) / (rt)) Expression 2 holds.

Here, pcd is the radius from the center of the curved traction surface at the time of completion of the CVT disk to the center of the work 28 (diameter is PCD), φ is the outer radius of the work 28, and r is the completion of the CVT disk. Shows the radius of the traction surface at the time.

At the time of the inner hit shown in FIG. 3, t = t '× cos (π / 2−θ ₁ −ω 2) Equation 3 ω 2: Arcsin ((h 1 −h 2) / (rt)) Equation 4 holds.

Here, h1 is C from the bottom of the work 28.
The height to the center of the curved surface of the traction surface when the VT disk is completed is shown, and h2 is the height of the work 28.

From the above equation, the cutting depth t '/ t becomes a value larger than 1 in both the case of the outer hit and the inner hit, whereby the apparent allowance becomes larger than the actual allowance. There is a problem that time is long.

Further, unless the grinding wheel interference diameter is reduced as the swing angle is increased, interference with the grinding wheel at the outer peripheral portion of the disk occurs, and the work 28 is not grounded in line contact at the outer peripheral portion, but the surface of the work 28 is in contact with the surface. It is ground and its shape drops.

As a result, when the work 28 is ground, the external dimensions of the grindstone 26 are reduced accordingly. Therefore, if the usable grindstone diameter is small, the spindle on which the grindstone 26 is mounted must be rotated at a high speed in order to increase the grindstone peripheral speed. In this case, the diameter of the spindle shaft becomes thinner accordingly, and the rigidity is reduced. Therefore, if the grindstone 26 is rotated at a high speed in order to increase the processing efficiency, there is an anxiety in terms of rigidity. The same problem occurs not only when the diameter of the grindstone becomes smaller as it is used but also when the diameter of the grindstone is small in advance.

When the diameter of the grindstone is small in advance, the usable range of the grindstone 26 is small, so the frequency of replacing the grindstone 26 increases. For this reason, it takes time to replace the grinding machine, and the operation time of the grinding machine is shortened, and the productivity is not improved, which is disadvantageous in the machining cycle.

Further, when the diameter of the grindstone used is small, the number of abrasive grains on the surface of the grindstone acting on the processing decreases. For this reason, the dressing interval is shortened due to clogging of the grindstone or the like, which is disadvantageous in the processing cycle.

If the diameter of the grindstone used is smaller than a certain value, the construction of the grinding machine becomes difficult. That is, the bracket holding the spindle and the grindstone mount on which the spindle is mounted require a certain mass or size irrespective of the grindstone diameter, so that it is difficult to configure a grinding machine having only a small grindstone diameter.

The present invention has been made in view of the above circumstances, and has as its object the purpose of performing grinding within an appropriate range of the main shaft swing angle and forming a grindstone having a diameter equal to or larger than a predetermined size. An object of the present invention is to provide a method for grinding a traction surface of a half toroidal CVT disk.

[0018]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, there is provided a holding mechanism for holding a half toroidal CVT disk having a predetermined allowance, and grinding the half toroidal CVT disk. A traction surface grinding method for a half toroidal CVT disk, comprising: a machining mechanism having a tool; and performing a grinding process by using a grinding machine in which one of the half toroidal CVT disk or the tool is inclined at a desired angle with respect to the other. The cutting angle, which is the angle formed by the cutting direction of the tool with respect to the axis of the half-toroidal CVT disk, is defined as the ratio of the apparent cutting dimension to the predetermined cutting dimension. Part value and the traction With respect to the angle of the contact surface and the tool become equal value when a traction plane peripheral portion, a toroidal CVT disk traction surface grinding wherein the set in the range of 15 degrees ±.

According to the first aspect of the present invention, the cutting angle, which is the angle formed by the cutting direction of the tool with respect to the axis of the half toroidal CVT disk, is set to the traction of the cutting ratio, which is the ratio of the apparent cutting size to the predetermined cutting size. The angle when the value when the contact between the surface and the tool is on the traction surface outer peripheral side and the value when the value when the contact between the traction surface and the tool is on the inner peripheral portion of the traction surface is ± 15 degrees. By setting the range, it is possible to suppress the apparent cutting magnification to a small range without being so large. Therefore, the processing time can be reduced.

According to a second aspect of the present invention, there is provided a holding mechanism for holding a half toroidal CVT disk having a predetermined allowance, and a processing mechanism having a tool for grinding the half toroidal CVT disk. In a method for grinding a traction surface of a half toroidal CVT disk in which one of a toroidal CVT disk and a tool is ground by a grinding machine inclined at a desired angle with respect to the other, a surface perpendicular to the axis of the half toroidal CVT disk is provided. The angle difference between the swing angle, which is the angle made by the rotation axis of the tool, and the cutting angle,
A method for grinding a traction surface of a half toroidal CVT disk, wherein the traction surface is set to a range of 15 degrees or less.

According to the second aspect of the present invention, since the angle difference between the tool swing angle and the cutting angle is individually set within a range of 15 degrees or less, the tool swing angle at which the wheel interference diameter becomes large is selected. And the angle difference is 15 degrees or less, so that the load applied to the tool in the thrust direction does not increase, thereby preventing a problem that a thrust load is applied to the tool, which breaks or deteriorates machining accuracy. It becomes possible. In this case, if the cutting angle and the swing angle are set appropriately, both reduction of the cutting magnification and maximization of the tool diameter can be achieved, and the overall grinding performance of the work can be improved.

According to a third aspect of the present invention, there is provided a holding mechanism for holding a half toroidal CVT disk having a predetermined allowance, and a processing mechanism having a tool for grinding the half toroidal CVT disk. In a method for grinding a traction surface of a half toroidal CVT disk in which one of a toroidal CVT disk and a tool is ground by a grinding machine inclined at a desired angle with respect to the other, the maximum diameter of the tool is set to the traction of the half toroidal CVT disk. Interference grinding wheel diameter calculated from the dimension pcd between the center of curvature of the curved surface of the surface and the rotation center of the half toroidal CVT disk, the radius of curvature r of the traction surface, the outer diameter of the traction surface φ, and the swing angle Within the range of 0.9 to 0.5 times And, the half toroidal CVT
A traction surface of a half-toroidal CVT disk, wherein an angle difference between a swing angle, which is an angle formed by a rotation axis of the tool with respect to a plane perpendicular to an axis of the disk, and the cut angle is set within a range of 15 degrees or less. It is a grinding method.

According to the third aspect of the present invention, the interference diameter of the tool is obtained from the swing angle and the size of the work, and the interference diameter of the tool is set to 0.1 mm.
Since the diameter of the tool is set within the range of 9 to 0.5 times, the diameter of the tool actually used can be maximized within the possible range. As a result, it is possible to shorten the grinding time, and it is possible to perform an appropriate grinding process capable of improving both the grinding efficiency and the grinding accuracy.

According to a fourth aspect of the present invention, the angle difference between the swing angle, which is the angle formed by the rotation axis of the tool with respect to the plane perpendicular to the axis of the half toroidal CVT disk, and the cutting angle is within a range of 15 degrees or less. 2. The method for grinding a traction surface of a half toroidal CVT disk according to claim 1, wherein the traction surface is set.

According to the fourth aspect of the present invention, the apparent cutting magnification can be suppressed to a small range without being so large, so that the machining time can be shortened and the load applied to the tool in the thrust direction does not increase. In addition, it is possible to prevent problems such as breakage of the tool or deterioration of machining accuracy due to the addition of the thrust load to the tool.

According to a fifth aspect of the present invention, the maximum diameter of the tool is defined by the center of curvature of the curved traction surface of the half toroidal CVT disk and the half toroidal CVT.
The interference whetstone diameter 0.9 calculated from the dimension pcd with respect to the rotation center of the disk, the radius of curvature r of the traction surface, the radius φ of the outer diameter of the traction surface, and the swing angle is 0.9.
5. The method for grinding a traction surface of a half toroidal CVT disk according to claim 4, wherein the traction surface is set within a range of 2 times to 0.5 times.

According to the fifth aspect of the present invention, the apparent cutting magnification can be suppressed to a small range without being so large, so that the processing time can be shortened and the load applied to the tool in the thrust direction does not increase. In addition, it is possible to prevent problems such as breakage of the tool or deterioration of machining accuracy due to the addition of the thrust load to the tool. And
Along with the fact that the diameter of the tool actually used can be maximized within the possible range, it is possible to perform an appropriate grinding process that can improve both the grinding efficiency and the grinding accuracy.

According to a sixth aspect of the present invention, the cut angle and the swing angle are made equal, and the swing angle is set to approximately 15 to 40.
The traction surface grinding method for a half toroidal CVT disk according to any one of claims 1 to 5, wherein the traction surface is set within a range of degrees.

According to the sixth aspect of the present invention, by setting the swing angle of the tool within a range of approximately 15 degrees to 40 degrees,
The grinding wheel interference diameter of the half toroidal CVT disk can secure approximately 60% or more of the case where the swing angle is 0 degree. For this reason,
It is possible to prevent the diameter of the tool from being reduced, thereby reducing the necessity of rotating the tool at high speed. And, by securing the grinding wheel interference diameter, the number of abrasive grains on the tool surface acting on the processing can be sufficiently secured without decreasing, so that the dress frequency and replacement frequency of the tool can be reduced, which is advantageous in the processing cycle. Become. This makes it possible to increase the time ratio applied to the actual processing of the grinding processing, thereby improving the grinding ability. Further, the apparent allowance dimension can be suppressed to twice or less the actual allowance dimension, and the processing time can be shortened. Then, since the diameter of the tool is set so that the tool does not cause interference, the grinding process can be performed by removing causes of surface quality defects such as drooping of the bus shape and grinding return.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

In FIG. 7, the swing angle θ ₁ (and a cutting angle θ _2, which is set to be equal to the swing angle θ _1, which will be described in detail later) is a certain angle (θ ₁ (= θ ₂ ); 4
0 degree range) Indicates a grinding machine.

The grinding machine 20 shown in FIG. 1 has a grinding mechanism (working mechanism) 21 and a drive mechanism (holding mechanism) 22. The grinding mechanism 21 includes a cutting table 23, and the cutting table 23 is configured to interlock with a servomotor 25 as a first driving unit via a ball screw 24. The servo motor 25 is provided at a fixed part.

Therefore, when the servomotor 25 is driven to rotate, the cutting table 23 is driven in the vertical direction (hereinafter, this direction is referred to as the X direction).

A drive motor (not shown) for rotating and driving the grindstone (tool) 26 is provided inside the cutting table 23, and the driving force generated by this drive motor is applied to the grindstone 26 via the grindstone spindle 27. Provided for rotary drive. The tip of the grinding wheel spindle 27 has a grinding wheel 26
A tool holding table 27a for holding the tool is provided.

The grinding wheel 26 has a ground surface having a radius corresponding to a traction surface of a half toroidal CVT disk 28 (hereinafter referred to as a work 28) completed after the grinding process. It is formed in a shape. Therefore, before the grinding process, the work 2
8 has an allowance, the radius of the surface to be ground of the work 28 is formed smaller than the diameter of the ground surface on the outer peripheral side of the grindstone 26.

It is necessary to fix the work 28 to be ground to the cross slide 29 by chucking, and thereafter move the work 28 with the grinding. A drive mechanism 22 is provided as a device for this purpose. The drive mechanism 22 has a base 30 serving as a work spindle table, and the base 30 is provided with a turning table 31. Therefore, the inclination angle of the cross slide 29 of the swivel table 31 with respect to the base 30 can be adjusted.

A turning guide 32 for performing a regular turning operation is provided inside the turning table 31. The swivel guide 32 is formed, for example, in a groove shape, and has a function of guiding the swivel drive of the swivel table 31 and regulating the tilt angle adjustment operation of the grindstone 26 with respect to the cutting axis.

A work spindle (not shown) is provided inside the swivel table 31, and the work spindle is driven to rotate about a rotation axis.

Work 2 fixed to cross slide 29
Reference numeral 8 indicates that the rotation axis B can be appropriately rotated with respect to the cutting axis A so that the rotation axis B can be set to a predetermined angle. Have been.

The base 3 having the above-described swivel table 31
0 is connected to a servo motor 33 which is a second driving means. The servo motor 33 is capable of driving the base 30 in a direction perpendicular to the cutting axis A and in a direction parallel to the grinding wheel spindle 27 (hereinafter referred to as the Y direction).

The servo motors 25 and 33 are connected to drive circuits 40 and 41, respectively.
Are both connected to the numerical controller 42. The numerical control device 42 receives, for example, master data, which is the shape of the workpiece 28 after machining, and actual dimensions of the workpiece 28, and determines the machining amount of the workpiece 28 according to the input values.

The drive circuits 40 and 41 and the numerical controller 42 function as a position control / correction unit.

For this reason, a control command is given to the drive circuit in accordance with the machining amount of the work 28 calculated by the numerical controller 42, and the drive circuits 40 and 41 are electrically connected to the servomotors 25 and 33 in accordance with the control command. Control of the current. Thereby, the X direction of the cutting table 23 and the Y
The movement in the direction can be set to a desired position.

The numerical controller 42 is provided with a keyboard 43 for inputting numerical values, and the display CRT 44 can display positions in the X and Y directions.

A grinding method using the grinding machine 20 having the above configuration will be described below.

First, according to the equation 1 described in the above-mentioned problem to be solved by the invention, the apparent allowance dimension t 'is
It becomes larger than the actual allowance dimension t. Here, t '/ t
Is the infeed rate, the infeed rate in the case of the outside hit is the infeed rate 1, and the infeed rate in the inside hit is the infeed rate 2.
From FIGS. 2 and 3, cutting magnification 1: t ′ / t = 1 / cos (θ ₁ + ω1) Equation 5 Cutting magnification 2: t ′ / t = 1 / cos (π / 2−θ ₁ −ω2) ) ... Formula 6 In this case, as the cutting magnification 1 and the cutting magnification 2 are as close to 1 as possible, the apparent allowance dimension t 'approaches the actual allowance dimension t. Since the workpiece 26 and the workpiece 28 are in contact with each other, the greater the cutting magnification, the more time is required for grinding.

Here, the interference diameter of the grindstone 26 changes depending on the swing angle θ ₁ of the grindstone 26. The relationship between the whetstone interference diameter and θ ₁ will be described below with reference to FIGS. In addition, although the grindstone interference diameter is a diameter, the description also uses a grindstone interference radius Rw which is の of the grindstone interference diameter.

First, the distance from the cross section of the grindstone 26 passing through the position D to the center of the grindstone is Rc, the radius of the work 28 is φ, the distance from the center of the diameter of the work 28 to the center of the traction surface of the work 28 is pcd, and the center of the traction surface is pcd. Let a be a depth of a distance c from a: a = (r ² −c ² ) ^1/2 − (r ² − (φ−pcd) ² ) ^1/2 Equation 7 In the drawing, b, d B = a / sin (π / 2−θ ₁ ) Equation 8 d = bcos (π / 2−θ ₁ ) Equation 9

Here, in FIG. 5 (a), e = (φ ² − (pcd + c + d) ² ) ^1/2 Equation 10 Further, in FIG. 5 (b), (Rc−b) ² + e ² = Rc ² ... Expression 11 Expanding this, Rc = (b ² + e ² ) / 2b Expression 12 From this, Rc = {b ² + (φ ² − (pcd + c + d) ² )} / 2b Expression 13

[0050]

(Equation 1)

[0051] Therefore, Rw = Rc '+ r ( 1-sinθ 3) = Rc' + r (1-sin [π / 2-θ 1 -Arcsin (c / r)]) = Rc '+ r (1-cos [θ _{1 + Arcsin (c / r)} ]) ... equation 14 from this equation, the larger the swing angle theta _1, it can be said that the value of Rw is also reduced accordingly. That is, by increasing the theta _1, with depth of cut of the apparent increases, the grindstone interference diameter becomes small, the processing problem occurs.

FIG. 6 shows the relationship between the cutting magnifications 1, 2 and the grinding wheel interference diameter and the main shaft swing angle θ ₁ .

In this figure, the main shaft swing angle θ ₁ is 0
In the case of degrees, the interference diameter is exactly 100%, and the relationship is such that as the swing angle increases, the grinding wheel interference diameter decreases.

When the swing angle θ ₁ increases from 0 degrees, first, an inner hit occurs between the work 28 and the grindstone 26. In this case, the cutting magnification 2 when the inner hit occurs at −5 degrees is the maximum. Is taking the value. As θ ₁ increases from this angle, the cutting magnification 2 decreases, and θ ₁ = 15
In the case of degrees, the cutting magnification 2 becomes approximately 2, and when θ ₁ further increases, a double hit occurs at θ ₁ = 30 degrees. Note that the cutting magnification 1 becomes larger as θ ₁ becomes larger.
The value is gradually increasing.

If θ ₁ is still large after the hitting, the outside hit occurs between the work 28 and the grindstone 26, and the cutting magnification 1 increases. Then, when θ ₁ = 40 degrees, the cutting magnification 1 becomes substantially 2, and when θ ₁ becomes larger than this, the cutting magnification further increases. In this case, as θ ₁ increases, the cutting magnification 2 approaches 1 and decreases.

Here, it is preferable that both of the cutting magnifications 1 and 2 have a small value because the time required for the grinding process is short and the efficiency is improved, which is preferable. 2 is a correlation, and when one increases, the other decreases. Therefore, it is necessary to suppress the values of the cutting magnification 1 and the cutting magnification 2 within a predetermined range. Specifically, when the swing angle θ ₁ is in the range of 15 degrees to 40 degrees,
The cutting magnification 1 and the cutting magnification 2 both become values of approximately 2 or less,
This is preferable in terms of processing efficiency. When swing angle theta ₁ is other value may be any cutting magnification 1 becomes a value larger than 2, which is intended to take the processing time.

Further, as θ ₁ increases, the grindstone interference diameter decreases. As shown in FIG. 6, when θ ₁ = 15 degrees, 85% of θ ₁ = 0 degrees is obtained, and when θ ₁ = 40 degrees, θ ₁ = 0 degrees. 60% of the time. However, when θ ₁ is larger than 40 degrees, the interference diameter of the grindstone is further reduced, and a problem occurs in processing as described above.

Therefore, it is preferable to set the swing angle θ ₁ in the range of 15 to 40 degrees in view of the cutting magnifications 1 and 2 and the grinding wheel interference diameter.

Table 1 below shows the test piece No. of the half toroidal CVT disk. Table 2 shows the test piece No. 1. 1 shows a relationship between a swing angle θ _{1 of 1} and a grinding wheel interference diameter ratio and cutting magnifications 1 and 2. Similarly, Tables 3 and 4 show test piece Nos. 2 shows the relationship between the shape data 2, the swing angle θ ₁ , the grinding wheel interference diameter ratio, and the cutting magnifications 1 and 2. The angles of the traction surface in Tables 1 and 3 (and Tables 5 and 8) are defined as a straight line connecting the outer edge and the inner edge of the traction surface, and a perpendicular line rising from the intersection of this straight line and the axis of the work. (See FIG. 2).

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Table 3]

[0063]

[Table 4]

According to the grinding method using such a grinding machine 20, the inclination angle with respect to the radial direction of the grindstone 26 with respect to the axis of the work 28 is set in a range of approximately 15 degrees to 40 degrees. t 'can be suppressed to within twice the actual allowance dimension t. For this reason, since the processing distance can be suppressed short, the processing time can be reduced.

Further, since the interference diameter of the grindstone becomes approximately 60% or more when the swing angle is 0 °, the necessity of rotating the grindstone 26 at high speed is reduced.

Further, since the grinding wheel interference diameter can be ensured, it is possible to secure a predetermined amount without reducing the number of abrasive grains on the grinding wheel surface acting on the grinding process. The need to perform 26 dresses is reduced. This is advantageous in terms of the processing cycle, and the time required for replacing the grindstone 26 is reduced, so that the productivity is improved.

While the embodiment of the present invention has been described above, the present invention can be variously modified. This is described below.

In the above-described embodiment, during the grinding, the swing angle θ ₁ may be fixed or changed. When the swing angle θ ₁ is changed, it is necessary to perform control such as position control of the grindstone 26 and the work 28. However, if this control can be performed to set an appropriate θ ₁ , the processing time can be further reduced. be able to.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to FIG. 1 and FIGS.

In the above-described embodiment, the grinding stone 26 with respect to the axis of the work 28 such as a half toroidal CVT disk is used.
The swing angle θ ₁ (and the cut angle θ ₂ ) from about 15 degrees to 4
Although the angle is within the range of 0 degrees, the appropriate angle depends on the size of the work 28, and is related to a grinding process capable of coping with a work 28 having a preferable angle of 15 degrees or less.

FIG. 8 shows the cutting angle θ ₂ and the swing angle θ ₁ used in the following description.

In this figure, the grindstone spindle 27 fixing the grindstone 26 is connected to the cutting table 2 shown in FIG.
3 is attached to a grindstone table 50 (not shown). The grindstone table 50 is provided with a feed screw 51, and by adjusting the feed amount, the inclination angles of the grindstone 26 and the grindstone spindle 27 with respect to the grindstone table 50 can be adjusted. In addition, the grindstone 26 is
In order to make a cut into 8, a grindstone table drive motor 52 is provided. Therefore, the grinding wheel table drive motor 5
By operating No. 2, it is possible to cause the wheel table 50 to proceed in a predetermined direction (cutting direction W).

In this figure, the angle formed between the central axis P of the work 28 and the cutting direction W of the grindstone table 50 is defined as a cut angle θ _2, and is perpendicular to the central axis M of the grindstone 26 and the central axis P of the work 28. The angle formed by the vertical line S is defined as a swing angle θ ₁ .

For this reason, the cutting direction W and the central axis M
Are orthogonal, the cutting angle θ _TwoAnd swing angle θ₁Is
However, if they are not orthogonal, they must be equal.
No.

Hereinafter, description will be made using the cutting angle θ ₂ and the swing angle θ ₁ .

In the first embodiment described above, the cutting magnification 1
And the cutting rate 2 are determined by the outer hit and the inner hit, respectively. However, the fact that the cutting rate is actually minimized is that the grindstone 26 simultaneously performs the inner hit and the outer hit. Is the case.

That is, when the inner hit and the outer hit are performed simultaneously, as shown in FIG. 11, the traction surface of the work 28 and the grinding surface of the grindstone 26 are provided in an arc shape having a constant radius. As a result, the inner and outer perimeters of the cutting rate are equal.

In this case, from the first embodiment described above,
Using the cutting angle θ ₂ , cutting magnification 1: t ′ / t = 1 / cos (θ ₂ + ω1) Equation 15 Cutting magnification 2: t ′ / t = 1 / cos (π / 2−θ ₂ −) ω2)... Expression 16 where the actually applied cutting magnification is minimized when cutting is performed so that the grindstone 26 simultaneously starts contacting the outer periphery and the inner periphery of the traction surface of the work 28. FIG. 11 shows an image diagram in this case.

At this time, the cutting angle θ ₂ is determined by the cutting magnification 1
And the cutting magnification 2 become equal, and θ ₂ at that time
Is obtained, θ ₂ = (π / 2−ω1−ω2) / 2...

As described above, the cutting magnification is equal to the predetermined allowance t.
When machining at a constant cutting speed, from the viewpoint of shortening the machining time, it is possible to perform machining at this cutting angle that minimizes the cutting magnification. desirable.

In this case, from FIG. 9 and FIG. 10, when ω1 and ω2 are calculated and substituted, θ ₂ = _1/2 ＝ π / 2− (arcsin (φ−pcd) / r + arcsin (h1− h2) / r｝ ... Equation 18

When the cutting angle θ ₂ satisfies such a relationship, the cutting magnification is minimized, thereby minimizing the processing time.

Here, when grinding the traction surface of the work 28, the generatrix shape of the grindstone 26 is transferred to the traction surface of the work 28 over the entire traction surface up to the edge portion E of the work 28 shown in FIGS. Is required. Hereinafter, the contact between the grindstone 26 and the work 28 in a region other than the predetermined grinding area in the vicinity of the edge portion E is referred to as “interference”, and if the interference occurs, the bus line shape of the traction surface of the work 28 is degraded. Occurs. In the following description, the maximum diameter of the grindstone 26 that can perform the grinding without causing the grindstone 26 to interfere with the work 28 is obtained.

First, as shown in FIG. 12, in order to prevent the grindstone 26 and the work 28 from interfering with each other on the traction surface of the work 28, the edge portion F of the outermost diameter portion of the traction surface of the work 28 is required. Radiation N to tangent
It is necessary to prevent the grindstone 26 from protruding from an imaginary spherical surface Q having a radius from the intersection point O 'of the rotation axis of the workpiece 28 to the traction surface with the intersection point O' as the center. .

Here, in order to prevent the edge portion E from being interfered and ground, the traction surface is moved from the intersection point O ′ between the normal line N at the outermost point F on the traction surface and the central axis P as the center. The grindstone 26 needs to be housed so as not to protrude from the imaginary spherical surface Q whose radius is the distance to the wheel.

When the grindstone 26 is housed inside the spherical surface Q, all the remaining machining points can be housed inside the spherical surface Q, thereby causing interference between the workpiece 28 and the grindstone 26. It is possible to polish the traction surface of the work 28 without causing the traction surface to work.

The maximum diameter of the grindstone 26 that can be machined without interference is determined by the following equation.

As shown in FIG. 12, first, assuming that the angle between the normal line of the outermost peripheral portion of the traction surface of the work 28 and the rotation axis of the work 28 is ω3, ω3 = arcsin ｛(φ-pcd) / r ｝ ... Equation 19 Therefore, the radius Rc of the portion of the grinding wheel 26 where the outermost peripheral portion of the traction surface of the work 28 is processed is determined by the swing angle θ.
With _{1, Rc = (φ / sinω3} ) · sin (π / 2-ω3 -θ 1) ... the formula 20.

Further, the maximum radius Rw of the grindstone 26 is given by: Rw = Rc + r {1−sin (π / 2−ω3−θ ₁ )} (21)

If the dimension (pcd, r, outer diameter) of the work 28 and the swing angle θ ₁ of the grindstone 26 are determined from the formula of the maximum radius Rw of the grindstone 26, the grindstone 26 capable of processing the work 28 is determined. It is possible to determine the maximum radius. That is, such a grindstone 26 becomes the grindstone 26 that can grind the traction surface of the work 28 most efficiently.

As described above, when the swing angle of the grindstone 26 is set so that the grindstone 26 hits the workpiece 28 and the outer diameter of the grindstone 26 is set based on the above-described Rw, the most efficient operation is achieved. The work 28 can be ground well.

Table 5 below shows the test pieces No. 3 and the test piece No. 3 is shown in Table 6. Cutting angle with respect to 4 and cutting magnification 1 and cutting magnification 2 at the cutting angle
Table 7 shows the results calculated by the above-described formulas of the swing angle and the grindstone interference diameter at the swing angle. FIG. 13 shows this graph.

[0093]

[Table 5]

[0094]

[Table 6]

[0095]

[Table 7]

From Table 6, the test piece No. Work 2 of 3
In No. 8, when the cutting angle is 31.6 degrees, both the cutting magnification 1 and the cutting magnification 2 are 1.46. If the cut angle takes a value other than the cut angle, either the cut magnification 1 or the cut magnification 2 will be a larger value. Therefore, the cutting magnification 1 and the cutting magnification 2
In both cases, when the value of 1.46 is taken, the cutting magnification becomes minimum.

Further, from the results in Table 6, the cutting angle was set to 3
If it is set in the range of 16.6 degrees to 46.6 degrees, which is 1.6 degrees ± 15 degrees, the cutting magnification can be suppressed to 2.12 or less. According to Table 7, if the swing angle is set to 31.6 degrees, which is the same as the cutting angle at which the cutting magnification is minimized, the grinding wheel interference diameter at that time is 424.1 mm.

However, when the outer diameter of the grindstone 26 takes this value, the grindstone 26 and the traction surface of the work 28 come into contact with each other, so that the grinding water does not enter the polished surface at the time of machining, and the polished portion is formed by friction. There is a problem of burning.

For this reason, the grindstone 2 actually used for polishing is used.
6 needs to have a diameter smaller than 381.7 mm which is 0.9 times as large as that. Note that the grindstone 26 having the standard size has a diameter of 355 mm.

Here, when the swing angle is set to 25 degrees, the grindstone interference diameter at this angle is 464 mm, and the grindstone 26 actually used for polishing is 0.9 times as large as 4 times.
It is necessary to use one having a diameter smaller than 17.6 mm.
5 mm.

Considering the grinding efficiency and the grinding accuracy, 355
It is considered that a grindstone diameter of 405 mm is more advantageous than a grindstone diameter of mm. Also, the cut angle is set to 25
When set to degrees, the cutting magnification is 1.68, which is 1.4 when the above-mentioned cutting angle is 31.6 degrees.
6, which is 115% of the cutting magnification.

However, in view of the grinding efficiency and the like, it is considered that the case with the swing angle of 25 degrees is the best overall grinding ability, and therefore the case with the swing angle of 25 degrees is the optimum value for the total grinding ability. It is considered to be.

Table 8 below shows the test piece No. 4 and the test piece No. 4 is shown in Table 9. 4, a cutting angle and a cutting magnification 1 and a cutting magnification 2 at the cutting angle.
Table 10 shows the results of the swing angle and the wheel interference diameter at the swing angle calculated by the above equation. FIG. 14 shows this graph.

[0104]

[Table 8]

[0105]

[Table 9]

[0106]

[Table 10]

According to Table 9, the test piece No. Work 2 of 4
In No. 8, when the cutting angle is 22.6 degrees, both the cutting magnification 1 and the cutting magnification 2 are 2.11, and the cutting magnification is the minimum value. According to Table 10, the swing angle is 22.6.
The grindstone interference diameter at the time is 216.8 mm, and the grindstone 26 actually used for polishing is 0.9 times that of the grindstone 26.
It is necessary to use a grindstone 26 having a diameter smaller than 5.1 mm. In this case, the grindstone 26 of the standard size is 180 m
m, so that the grindstone 26 of this standard size can be used in practice.

On the other hand, if the swing angle is set to 0 degree, the interference diameter of the grindstone at that time is 291.1 mm, and the grindstone 26 actually used for polishing is 0.9 times as large as 262.
It is necessary to use one smaller than 0 mm. In the case of the grindstone 26 having the standard dimensions, the diameter is 255 mm, and the diameter of the actual grindstone 26 uses this dimension. Therefore, when the swing angle is set to 0 degree, 1 when the swing angle is 22.6 degrees.
A grindstone 26 having a diameter of 41.7% can be used.

However, if the cut angle is set to 0 degree, which is the same as the swing angle, the cut magnification becomes 10, and the apparent allowance t 'becomes extremely large, resulting in a problem that processing time is required.

Therefore, the cutting angle and the swing angle are set to 1
If the angle is set to 5 degrees, the cutting magnification 2 becomes 2.82 times. 4 can be kept at 134% of 2.11 which is the minimum value of the cutting magnification.

When the cutting angle θ ₂ is different from the swing angle θ ₁ , the working surface of the grindstone 26 does not become symmetric,
The grinding force acting on the grindstone 26 and the work 28 acts not only in the radial direction of the grindstone 26 but also in the axial direction of the rotating shaft of the grindstone. Here, since the thrust rigidity in the axial direction of the grindstone 26 is weaker than the radial rigidity, it is not desirable that the grinding force acts in the axial direction. Therefore, it becomes better difference cutting angle theta ₂ and swing angle theta ₁ is less desirable.

Here, if the difference between the cutting angle θ ₂ and the swing angle θ ₁ is 15 degrees or more, the axial force component of the grinding force becomes too large, so that the difference between the two is within 15 degrees. Has become desirable.

That is, if | θ ₁ −θ ₂ | ≦ 15 °, the thrust load generated on the grindstone 26 can be reduced.

The test piece No. No. 3 and test piece no. 4
From the results in, the cutting angle θ _TwoThe cutting depth is the smallest
Angle within a range of ± 15 degrees, and the swing angle
Grinding stone diameter with the angle difference of cutting angle within 15 degrees
Within the range of 0.9 to 0.5 times the wheel interference diameter
For example, appropriate grinding that balances grinding efficiency and grinding accuracy is performed.
It becomes possible.

According to the method for grinding the traction surface of a half toroidal CVT disk, the cutting angle θ _{2 formed} by the cutting direction W of the grindstone 26 with respect to the axis of the work 28 is determined by changing the apparent cutting dimension to the predetermined cutting dimension. By setting the angle so that the cut-in magnification, which is the ratio, is within the range of ± 15 degrees, the apparent cut-in magnification can be suppressed to a small range without being so large.

In addition to this, a swing angle θ ₁ , which is an angle between the rotation surface direction of the grindstone 26 and the axis of the work 28, and
Since the angle difference from the cutting angle θ ₂ is set within the range of 15 degrees or less, the load applied to the grinding wheel 26 in the thrust direction does not increase, and therefore, the thrust load is applied to the grinding stone 26 and this breaks. Problems can be prevented beforehand.

Further, since the cutting angle θ ₂ is set within a range of ± 15 degrees with respect to the angle at which the cutting magnification becomes minimum,
If the cutting magnification is within this range, the cutting magnification does not need to be so large from the minimum value. In this case, by setting an appropriate cutting angle θ ₂ , the cutting magnification is reduced and the grinding wheel 2 is reduced.
6 can be maximized.

As a result, the grinding ability of the work 28 can be made totally excellent, and the grinding time can be shortened.

Also, in order to prevent the grinding stone 26 from causing interference,
Since the diameter of the grindstone 26 is set, it is possible to perform a grinding process by removing a cause of surface quality defects such as a drooping shape and a grinding return.

Further, the interference diameter of the grindstone of the grindstone 26 is obtained from the swing angle θ ₁ , and the diameter of the grindstone 26 is set within a range of 0.9 to 0.5 times the interference diameter of the grindstone 26, so that it is actually used. The diameter of the grindstone 26 can be maximized within a possible range. Thereby, the grinding time can be reduced.

Further, by combining these plural elements, it is possible to increase the peripheral speed of the grindstone without increasing the number of revolutions of the grindstone, thereby providing a grinding method capable of grinding with high rigidity and high efficiency. In addition, a grinder that satisfies these conditions can be a highly rigid and highly efficient grinder.

Therefore, it is possible to shorten the processing cycle time.

Further, since the usable range of the grindstone 26 can be sufficiently ensured, the frequency of dressing and replacement of the grindstone 26 can be reduced. As a result, the time ratio devoted to actual processing of grinding can be increased,
Therefore, it is possible to improve the grinding ability.

Although the second embodiment of the present invention has been described above, the present invention can be variously modified. This is described below.

In the above embodiment, the cutting angle θ ₂ is set to ± 1 with respect to the angle at which the cutting magnification becomes minimum in the grinding process.
Set within 5 degrees range of (1), cut the angle difference between the angle theta ₂ and swing angle theta ₁ to the range of 15 degrees or less (2), 0 interference diameter of the grindstone 26 that is calculated from the swing angle. The diameter of the grindstone 26 is set so as to be 9 to 0.5 times (3),
Although the grinding process is performed, a configuration that performs the grinding process that satisfies at least one of the conditions (1) to (3) may be employed.

In addition, various modifications can be made without departing from the scope of the present invention.

[0127]

As described above, according to the present invention,
The cutting angle of the tool with respect to the axis of the half toroidal CVT disk, the value when the contact between the traction surface and the tool of the cutting ratio, which is the ratio of the apparent allowance size to the predetermined allowance size, is on the traction surface outer peripheral side, When the contact between the traction surface and the tool is on the inner peripheral side of the traction surface, the angle becomes ±
Setting the angle difference between the swing angle and the cutting angle to a range of 15 degrees or less,
Furthermore, by setting the diameter within the range of 0.9 to 0.5 times the diameter of the interference grindstone calculated from the workpiece shape and the swing angle, the grinding can be performed within the appropriate range of the spindle swing angle. Thus, the apparent allowance dimension can be suppressed to twice or less the actual allowance dimension, and the processing time can be reduced. Further, since the diameter of the tool can be formed to a predetermined size or more, the necessity of rotating the tool at high speed is reduced, and the usable range of the tool can be sufficiently secured, and the frequency of tool replacement is reduced. This is advantageous in the processing cycle.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of a grinding machine according to an embodiment of the present invention.

FIG. 2 is a view showing a state in which a grinding stone and a half toroidal CVT disk according to the embodiment have an outside contact; FIG. 2A shows a case where a grinding stone and a half toroidal CVT disk have an outside contact; Image, (b) is an enlarged view of the outer contact portion between the grindstone and the half toroidal CVT disk.

FIG. 3 is a view showing a state in which the grindstone and the half toroidal CVT disk hit the inside according to the embodiment; FIG. 3A shows a case where the grindstone and the half toroidal CVT disk hit the inside; Image, (b) is an enlarged view of the inner contact portion between the grindstone and the half toroidal CVT disk.

4A and 4B are diagrams showing a dimensional relationship between a grindstone and a work passing through a position c according to the embodiment, and FIG. 4A shows a case where the grindstone and a half toroidal CVT disk are in contact at a position c. (B) is an enlarged view near a position c.

FIG. 5 is a diagram showing a dimensional relationship between a grindstone passing through a position c and a workpiece according to the embodiment, and FIG. 5A is a diagram showing a dimensional relationship near a position c in a plan view of the grindstone;
(B) is a figure which shows the contact state in the position c of a grindstone.

FIG. 6 is a view showing the relationship between θ ₁ and cutting magnifications 1 and 2 and a grinding wheel interference diameter according to the embodiment.

FIG. 7 is a side view showing a configuration of a grinding machine showing one embodiment of the present invention.

8 shows a cutting angle theta ₂ and swing angle theta ₁ relationship in the case of the second grinding a workpiece with grinding wheel according to an embodiment of the present invention.

FIG. 9 is a diagram showing a state in which the grindstone and the work according to the embodiment are in contact with the outside.

FIG. 10 is a view showing a state in which the grindstone and the work according to the embodiment hit inside.

FIG. 11 is a view showing a state in which the grindstone and the work according to the embodiment are in contact with each other.

FIG. 12 is a diagram showing an interference relationship between a grindstone and a work according to the embodiment.

FIG. 13 shows a test piece No. according to the embodiment. 3 is a graph showing a relationship between a cutting angle and a cutting magnification and a swing angle and a grinding wheel interference diameter in No. 3;

FIG. 14 shows test piece Nos. According to the embodiment. 4 is a graph showing a relationship between a cutting angle and a cutting magnification and a swing angle and a grinding wheel interference diameter in FIG.

[Explanation of symbols]

 Reference Signs List 20 grinding machine 21 grinding mechanism 22 drive mechanism 23 cutting table 26 grinding wheel 27 grinding wheel spindle 28 work

Claims (6)

[Claims] 1. A half toroidal C having a predetermined allowance
A holding mechanism for holding the VT disk, and a processing mechanism provided with a tool for grinding the half toroidal CVT disk, wherein one of the half toroidal CVT disk and the tool is inclined at a desired angle with respect to the other. In the method for grinding a traction surface of a half toroidal CVT disk for performing a grinding process by using a grinding machine, a cutting angle, which is an angle formed by a cutting direction of a tool with respect to an axis of the half toroidal CVT disk,
The value of the cutting ratio, which is the ratio of the apparent allowance dimension to the predetermined allowance dimension, when the contact between the traction surface and the tool is on the outer peripheral side of the traction surface, and the contact between the traction surface and the tool is the inner circumference of the traction surface. A method for grinding a traction surface of a half toroidal CVT disk, wherein the angle is set within a range of ± 15 degrees with respect to an angle at which the value is equal to the part side. 2. Half toroidal C having a predetermined allowance
A holding mechanism for holding the VT disk, and a processing mechanism provided with a tool for grinding the half toroidal CVT disk, wherein one of the half toroidal CVT disk and the tool is inclined at a desired angle with respect to the other. A traction surface grinding method for a half-toroidal CVT disk, wherein grinding is performed by a grinding machine, wherein an angle between a swing angle, which is an angle formed by a rotation axis of a tool with respect to a plane perpendicular to an axis of the half-toroidal CVT disk, and the cutting angle. A method for grinding a traction surface of a half toroidal CVT disk, wherein the difference is set within a range of 15 degrees or less. 3. Half toroidal C having a predetermined allowance
A holding mechanism for holding the VT disk, and a processing mechanism provided with a tool for grinding the half toroidal CVT disk, wherein one of the half toroidal CVT disk and the tool is inclined at a desired angle with respect to the other. In the method for grinding a traction surface of a half toroidal CVT disk, which performs a grinding process by using a grinding machine, the maximum diameter of the tool is set between the center of curvature of the curved surface of the traction surface of the half toroidal CVT disk and the rotation center of the half toroidal CVT disk. Dimensions pc
d, and the radius of curvature r of the traction surface, the diameter φ of the outer peripheral radius of the traction surface, and set within the range of 0.9 to 0.5 times the interference grindstone diameter calculated from the swing angle, and A half toroidal CVT disk, wherein an angle difference between a swing angle, which is an angle formed by a rotation axis of the tool with respect to a plane perpendicular to an axis of the half toroidal CVT disk, and the cutting angle is set within a range of 15 degrees or less. Traction surface grinding method. 4. The method according to claim 1, wherein a difference between a swing angle, which is an angle formed by a rotation axis of the tool with respect to a plane perpendicular to an axis of the half toroidal CVT disk, and the cutting angle is set within a range of 15 degrees or less. The method for grinding a traction surface of a half toroidal CVT disk according to claim 1. 5. The maximum diameter of the tool is defined as a dimension pcd between a center of curvature of a curved surface of a traction surface of the half toroidal CVT disk and a rotation center of the half toroidal CVT disk, a radius of curvature r of the traction surface,
5. The half toroidal CVT disk according to claim 4, wherein the diameter is set within a range of 0.9 to 0.5 times the interference grinding wheel diameter calculated from the radius dimension φ of the outer peripheral diameter of the traction surface and the swing angle. Traction surface grinding method. 6. The half according to claim 1, wherein the cut angle and the swing angle are made equal, and the swing angle is set in a range of about 15 to 40 degrees. A traction surface grinding method for toroidal CVT discs.