KR101602941B1 - Machining method of Roller Gear Cam using 5-Axis CNC Machine - Google Patents

Abstract

The present invention relates to a method for processing a roller gear cam using a five-axis computer numerical control (CNC) machine, and more specifically, to a method for processing a roller gear cam using a five-axis CNC machine comprising: an angle diagram definition step; a rough cutting step; and a fine cutting step. In the angle diagram definition step, data is extracted to form an angle between slanted surfaces on both sides of a thread (24) of a drum cam (20) to be bigger than the angle between rollers (12) of a follower (10). Moreover, in the fine cutting step, data is extracted to allow the width of a groove (22) of the drum cam (20) to be increased in a curved section of the groove (22) of the drum cam (20), compared with a linear section. Accordingly, controlling the inter-axial distance between the follower and the cam to reduce the backlash formed between the rollers of the follower and the cam is unnecessary such that the roller cam gear can be easily installed. Furthermore, the position of the follower can be stably maintained in the linear section of the groove of the cam, and stress concentrated on one of the rollers of the follower or a clearance generated on other roller can be prevented.

Description

Technical Field [0001] The present invention relates to a 5-axis CNC machine,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of machining a roller gear cam using a 5-axis CNC machining machine, and more particularly, to a 5-axis CNC machining machine, To a method of processing a roller gear cam using a CNC machining machine.

A gear or a belt is used to transmit the continuous rotation movement, but when it is necessary to transmit the movement while adjusting the angle and the angular speed according to an arbitrary rotation angle, a roller gear cam provided with a rotary type follower, Is commonly used.

The roller gear cam provided with the rotation type follower cam and the cam is provided with a plurality of rollers in the circumferential direction of the follower, and two rollers of the follower roller are simultaneously brought into contact with the inclined face of the cam with the groove, And is rotated in the direction of the groove.

These roller gear cams have almost no backlash and are excellent in durability due to rolling contact. Therefore, they are mainly used where precision drive is required, such as an index table and an automatic tool changer (ATC). However, in the case of index tables used in machine tools due to high precision of division, most roller gear cams are used, but the production of index tables is difficult due to the lack of 5-axis CNC machining technology.

In order to properly process the roller gear cam by using the 5-axis CNC machining machine, the mechanical characteristics of the roller gear cam and the structural characteristics of the CNC machining machine should be reflected in the modeling for performing the machining operation. (Computer Aided Manufacturing) does not provide this function.

Therefore, in order to process the roller gear cam, it is required to develop a dedicated program that can reflect the mechanical characteristics of the roller gear cam and the structural characteristics of the 5-axis CNC machining machine. For this reason, However, the shape of the tool is made to fit the machining width and machined by the full machining. This is due to the failure to precisely implement the tool path for the angle of rotation of the index table in the 5-axis machining.

On the other hand, a 5-axis CNC machining machine requires three position coordinates and two rotation coordinates for routing. In other words, unlike a 3-axis CNC machining machine, the 5-axis CNC machining machine rotates and tilts two axes except for the X, Y, and Z axes (position coordinates). Here, the two axes to be rotated and tilted are selected from a total of three axes, and are classified into three types according to which axes are rotated / tilted.

Figs. 1 to 3 are conceptual diagrams showing the types of 5-axis CNC machining machines. As shown in Figs. 1 to 3, an AC-type 5-axis CNC machining process that rotates about a C- (Fig. 1), an AB-type 5-axis CNC machining machine (Fig. 3) that rotates around an A axis vertically installed on the upper part of the horizontally installed B axis, horizontally installed Type 5-axis CNC machining machine (Fig. 2) having a B-axis in which the main shaft is tilted. Accordingly, even when cutting a workpiece using a 5-axis CNC machining machine, the current machining position of the tool for finishing varies depending on which type of 5-axis CNC machining machine is used.

Therefore, in order to accurately determine the tool path of a 5-axis CNC machining tool, machining data must be generated to match the spindle type of the 5-axis CNC machining tool.

In order to calculate the tool path of an accurate 5-axis CNC machining machine, the Applicant has been able to derive an angle diagram according to the main axis type of a 5-axis CNC machining machine as in Patent Documents 1 and 2, I have received a patent on the method.

However, conventionally, in order to eliminate the backlash between the roller and the cam of the follow-up roller, as shown in the figure, the distance between the follower roller and the cam is adjusted to closely contact the roller and the cam, have.

In addition, there is no problem in the straight section where the rollers are symmetrical to each other, but there is a problem that noise occurs in the curved section. That is, in the case of the curved section, one roller is brought into close contact with the cam, while the other roller may be formed with a gap between the cam and the cam, thereby generating noise.

KR 10-1200171 B1 (June 12, 2012) KR 10-1199037 B1 (Nov. 7, 2012)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a five-axis CNC machine for increasing the width of a mountain formed between running grooves during processing of a roller gear cam, And a method of processing a roller gear cam using a processing machine.

In order to solve the above problems, a method of machining a roller gear cam using a five-axis CNC machining machine according to the present invention is a method of machining a roller gear using a five-axis CNC machining machine including an angle line definition step, In the method of machining a cam, in the step of defining the angle line, data is extracted so that the angle of inclination of the both sides of the drum cam in the straight section of the groove of the drum cam is larger than the angle of the roller of the follower roller .

In order to solve the above problems, a method of machining a roller gear cam using a 5-axis CNC machining machine according to the present invention is a 5-axis CNC machining machine comprising an angle line defining step, a roughing machining defining step and a finishing machining defining step In the method of processing a roller gear cam, the finishing process definition step is characterized in that data is extracted so that the width of the groove of the drum cam in the curve section of the groove of the drum cam is increased relative to the straight section.

In the method of processing a roller gear cam using a 5-axis CNC machining machine according to the present invention, it is not necessary to adjust the distance between the follower and the cam to reduce the backlash generated between the roller and the cam of the follower roller, Be easy

Further, in the method of machining a roller gear cam using a 5-axis CNC machining machine according to the present invention, the position of the follower can be stably maintained in the straight section of the groove of the cam, It is possible to prevent the stress from concentrating on any one of them and to cause a gap on the other.

1 to 3 are conceptual diagrams showing kinds of a 5-axis CNC machining machine
4 is a front view showing the roller gear cam according to the present invention.
Fig. 5 is a view showing a cam curve showing the amount of displacement of the rotational angle of the follower according to the rotational angle of the drum cam
Fig. 6 is a front view
7 is a view showing a cam curve showing the amount of displacement of the rotational angle of the follower according to the rotational angle of the drum cam,
8 shows a cam curve
9 is a conceptual view showing a machined drum cam
Figs. 10 and 11 are conceptual diagrams showing a machining process of a 5-axis CNC machining tool

Hereinafter, a method of machining a roller gear cam using a 5-axis CNC machining machine according to the present invention will be described in detail with reference to the accompanying drawings.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of machining a roller gear cam using a 5-axis CNC machining machine, FIG. 6 is a front view of the follower, FIG. 7 is a cam curve showing the amount of displacement of the rotational angle of the follower according to the rotational angle of the drum cam by roller position, FIG. FIG. 9 is a conceptual diagram showing a machined drum cam, and FIGS. 10 and 11 are conceptual diagrams showing a machining process of a 5-axis CNC machining machine.

A method of machining a roller gear cam using a 5-axis CNC machining machine according to the present invention comprises an angle line definition step, a roughing machining definition step and a finishing machining definition step.

Before explaining the method of processing the roller gear cam using the 5-axis CNC machining machine according to the present invention, the roller gear cam 100 will be briefly described.

As shown in FIG. 4, the roller gear cam 100 includes a follower 10 on which a plurality of rollers 12 are installed along a side surface thereof; And a drum cam 20 having a groove 22 into which the roller 12 is inserted and a peak 24 formed between the groove 22.

When the drum cam 20 is rotated, the roller 12 of the follower 10 is kept stationary or moved according to the shape of the groove 22 of the drum cam 20 so that the follower 10 is stopped or moved . Specifically, when the groove 22 of the drum cam 20 is parallel to the circumferential direction of the drum cam 20 (hereinafter referred to as a "straight line section"), even if the drum cam 20 rotates, When the groove 22 of the drum cam 20 is formed so as not to be parallel to the circumferential direction of the drum cam 20 (hereinafter, referred to as a 'curved section'), The roller 12 is moved along the groove 22 and the follower 10 is rotated.

In order to generate the design and machining program of the roller gear cam 100, geometrical conditions such as the installation relationship of the follower 10 and the drum cam 20 are required. Specifically, the diameter and the width of the drum cam 20, The distance between the center of the drum cam 20 and the center of the follower 10, the diameter of the roller 12, the angle between the rollers 12, the distance between the end of the roller 12 and the center of the follower 10 Do.

The relationship between the rotation angle of the follower 10 and the drum cam 20 is as shown in FIG. 5, and the smooth connection between the straight line section and the curve section must be smoothly formed for smooth movement of the roller 12.

The construction steps of the method of processing the roller gear cam using the 5-axis CNC machining machine according to the present invention will be described below.

(1) Definition step of angle line

In order to form the groove 22 of the drum cam 20 using the 5-axis CNC machining machine, it is necessary to firstly draw an angle with respect to the rotation angle of the drum cam 20 and the follower 10. In general, the angle line is a combination of straight lines. The step of defining the angle line is a step of converting an angle line composed of a combination of straight lines into a curve. Specifically, the groove 22 of the drum cam 20 is curved The point of time that changes into a section is converted into a sine curve and defined. There are various methods of defining sinusoidal curves. For example, a mathematical expression for converting a sinusoidal curve into a sinusoidal curve is disclosed in Patent Document 1 and Patent Document 2.

Since the present invention aims to increase the width of the groove 22 of the drum cam 20, a data extraction method for the purpose will be described below in the step of defining the angle line.

It is necessary to first extract data relating to the rotation and tilting in order to widen the width of the groove 22 of the drum cam 20 so that the rotation angle of the drum cam 20 and the rotation angle of the follower 10 ) The change is divided into smiles and displayed as data 1 below.

[Data 1]

(? ₁ ,? ₁ ), (? ₂ ,? ₂ ), (? ₃ ,? ₃ ) ... (? _n ,? _n )

As shown in FIG. 6, six rollers 12 of the follower 10 are provided and the angle is 60 degrees. Therefore, each roller 12 (the rollers 12 in the vertical or horizontal symmetry relationship with the reference roller 12 ) Of the drum cam 20 and the rotation angle? Of the follower 10 are divided by a minute to display data 2 as shown below.

[Data 2]

(? ₁ ,? ₁ + 120?), (? ₂ ,? ₂ + 120? (? _n ,? _n + 120)

(? ₁ ,? ₁ + 60?), (? ₂ ,? ₂ + 60? (? _n ,? _n + 60)

(? ₁ ,? ₁ ), (? ₂ ,? ₂ ), (? ₃ ,? ₃ ) ... (? _n ,? _n )

(? ₁ ,? ₁ -60), (? ₂ ,? ₂ -60) ... (? _n ,? _n -60)

(? ₁ ,? ₁ -120), (? ₂ ,? ₂ -120) ... (? _n ,? _n -120)

The relationship of the rotational angle of the follower 10 with respect to the position of each roller 12 in accordance with the rotational angle of the drum cam 20 is expressed in the range of the contact angle of the maximum roller 12 with respect to the width of the drum cam 20 The present invention designates the range in which the drum cam 20 can contact the roller 12 as 110 DEG as an embodiment. Therefore, when the groove 22 formed in the drum cam 20 is displayed as shown in FIG. 7, if a section exceeding 110 degrees is deleted with reference to one line, it is displayed as shown in FIG. And each line is numbered to facilitate classification.

If the information of ① to ④ curve is displayed like data 2, it is same as the data 3 below. For reference, each curve corresponds to the shape of the groove 22 to be formed in the drum cam 20. Corresponding to each curve, the first curve corresponds to the path in which the first roller 12a is moved, and the second curve corresponds to 2 The curve 3 corresponds to the path along which the third roller 12c is moved and the curve 4 corresponds to the path along which the fourth roller 12d moves.

[Data 3]

① Curve: (θ ₁ , Ψ ₁ ), (θ ₂ , Ψ ₂ ), (θ ₃ , Ψ ₃ ) ... (? _n ,? _n )

② Curve: (θ ₁ , Ψ ₁ + 60 °), (θ ₂ , Ψ ₂ + 60 °), ... (? _n ,? _{n +} 60)

③ Curve: (θ ₁ , Ψ ₁ + 120 °), (θ ₂ , Ψ ₂ + 120 °), ... (? _n ,? _n + 120)

④ Curve: (θ ₁ , Ψ ₁ + 180 °), (θ ₂ , Ψ ₂ + 180 °), ... (? _n ,? _n + 180)

At this time, the present invention can minimize backlash between the crests 24 of the drum cam 20 and the rollers 12 of the follower 10 by adjusting the interval for each curve. More specifically, conventionally, the rotation angle of the follower 10 and the drum cam 20 with respect to the interval of the groove 22 to be processed by applying the roller angle of 60 degrees with the roller 12 is used as the data 3 The present invention is applied as Data 4 by applying the roller 12 at an angle of 60 DEG or more.

[Data 4]

① Curve: (θ ₁ , Ψ ₁ ), (θ ₂ , Ψ ₂ ), (θ ₃ , Ψ ₃ ), ... , (? _n ,? _n )

2) Curve: (? ₁ ,? ₁ + 60? +?), (? ₂ ,? ₂ + 60? +?), ... , (? _n ,? _n + 60 ° +?)

③ Curve: (θ ₁ , Ψ ₁ + 120 ° + 2α), (θ ₂ , Ψ ₂ + 120 ° + 2α), ... , (? _n ,? _n + 120 ° + 2?),

④ Curve: (θ ₁ , Ψ ₁ + 180 ° + 3α), (θ ₂ , Ψ ₂ + 180 ° + 3α), ... , (? _n ,? _n + 180 ° + 3?) (?> 0)

In the case of the curve that is adjacent to the m-th curve from the first curve, it can be generalized as Data 5. Is the angle between adjacent rollers 12.

[Data 5]

m second _{curve: (θ 1, Ψ 1 +} Φm + αm), (θ 2, Ψ 2 + Φm + αm), ... , (? _n ,? _n +? _m +? m)

As a result, data on the rotation angle of the follower 10 and the rotation angle of the drum cam 20 are input as data of the 5-axis CNC machining machine. For example, in the case of an AC-type 5-axis CNC machining machine, The rotation angle of the reverse rotation (10) is inputted to the A-axis tilting value and the rotation angle of the drum cam (20) is inputted to the C-axis rotation value.

9, the inclined surfaces on both sides of the ridge 24 of the drum cam 20 are gentler than those of the conventional art. The size of the angle formed by the extension lines of the two slopes becomes larger than 60 °. As a result, the drum cam 20 thus processed is pressed against the rollers 12 when the rollers 12 of the follower rollers 10 are brought into contact with the rollers 12 on both sides of the rollers 24, Backlash is not formed. For example, when the angle of the roller 12 is 60 °, the value of α is preferably 0.01. The value of α is set within a range not exceeding 0.1% with respect to an angle of 60 ° of the roller 12.

(2) Roughing definition step

The rough machining definition step is a step for extracting data for roughing machining the groove 22 of the drum cam 20 in a primary way. The roughing definition step is generally defined as an angle line definition step; And reflecting the structural characteristics of the processing machine. Specific details related to this are disclosed in Patent Document 1. The rotation angle relationship data of the drum cam 20 and the follower 10 during the angle line definition step of the roughing process defining step are obtained by rotating the rotation of the follower 10 and the drum cam 20 defined in the angle line definition step of the present invention, Each relationship data can be applied as it is.

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As shown in FIG. 8, from the start point ⓢ to the end point ① of the curves ① through ④, the rotation angle of the drum cam 20 and the rotation angle of the follower 10 from the start point to the end point for an arbitrary curve i If the relationship is displayed, data 6 can be displayed.

[Data 6]

_{(θ 1i, Ψ 1i + Φi} + αi), (θ 2i, Ψ 2i + Φi + αi), (θ 3i, Ψ 3i + Φi + αi), ... , (? _ni ,? _ni +? i +? i)

When the positional point of the groove 22 of the drum cam 20 is represented by data by applying a mechanical relationship to the data 6, data 7 can be displayed. For reference, the equations for obtaining X, Y, and Z are described in Patent Document 1.

[Data 7]

_{(x 1i, x 1i, z} 1i, ε 1i, θ 1i), (x 2i, x 2i, z 2i, ε 2i, θ 2i), ... , (x _ni , x _ni , z _ni ,? _ni ,? _ni )

The groove 22 of the drum cam 20 is rotated in the direction of the axis of the drum cam 20 by reflecting the mechanical condition of the roller 12 moving along the curve of the groove 22 of the drum cam 20 and the mechanical condition of the 5- To the curves of the center points of the co-axes of the 5-axis machine for machining the curves. At this time θ ε _1i and _1i of the formula 6-type AC- case of 5-axis machine is converted to C _1i and A _1i, the angle of the roller (12) θ _1i and _1i ε days when x, y, z is 5 - When the coplanar angle of the axis machine is changed (substantially the rotation of the index table), it must be changed by rotation transformation, and the principle related to this is described in Patent Document 1. Therefore, Expression 6 is expressed as data 8 as the center position data of the tool tip of the 5-axis machining tool.

[Data 8]

(X _1i , Y _1i , Z _1i , A _1i , C _1i ), (X _2i , Y _2i , Z _2i , A _2i , C _2i ), ... , (X _ni , Y _ni , Z _ni , A _ni , C _ni )

Next, there is a functionally unnecessary area for machining the roller gear cam. If an unnecessary area is determined, only the Y-axis can be shifted by the cutting width from the data along the cam curve and machined several times.

(2) Finishing process definition step

The finishing processing defining step is a step of extracting data for finishing to be performed after the roughing processing for primarily machining the center of the groove 22 of the drum cam 20 so as to clearly define the shape of the groove 22 in the curved section It is important to extract the data for formation. The finishing process definition step is generally defined as an angle line definition step; And reflecting the structural characteristics of the processing machine. Details related to this are described in Patent Document 2. The rotation angle relationship data of the drum cam 20 and the follower 10 during the angle line definition step of the finishing process definition step are the rotation angle of the drum cam 20 and the follower 10 defined in the angle line definition step of the present invention, Each relationship data can be applied as it is.

Further, the present invention can be applied to a data extraction method for increasing the width of the groove 22 of the drum cam 20 in the curve section in the step of reflecting the structural characteristics of the processing machine during the finishing process definition step. In the following, a data extraction method for the above purpose will be described in the finishing processing definition step.

All the data can be displayed in the data cluster by micro element according to the procedure, and the offset direction is changed according to the processing direction. If the finishing of the curve 22 of the groove 22 of the drum cam 20 is a downward cutting, the respective machining directions are determined, and in the case of the left side with respect to the machining advancing direction, the positive direction is offset in the minus direction. The offset amount corresponds to 1/2 of the difference between the width of the groove 22 of the drum cam 20 and the diameter of the tool. When this is formulated, the data cluster of the i-th left curve and the right curve is expressed as data 9 below.

[Data 9]

Left _{curve: (X 1i + δN x,} Y 1i + δN y, Z 1i, A 1i, C 1i), ... X _ni +? N _x , Y _ni +? N _y , Z _ni , A _ni , C _ni )

Right curves: (X _{1i -} δN _x , Y _{1i -} δN _y , Z _1i , A _1i , C _1i ), ... , (X _{ni -?} N _x , Y _{ni -?} N _y , Z _ni , A _ni , C _ni )

In data 9, N _x And N _y are an X component and a Y component of a normal unit vector at an arbitrary position of a curve formed by the groove 22 of the drum cam 20 and 隆 is a groove width of the drum cam and a tool diameter, / 2, so that the production of the roller gear cam can be completed by 5-axis machining.

The present invention can increase the width of the groove 22 of the drum cam 20 in the curve section by adjusting the value of C in the data 9. [ That is, in the case of an AC-type 5-axis CNC machining machine, the degree of inclination of the groove 22 of the drum cam 20 is determined in the curve section as the A axis is tilted while the C axis is rotated. For example, when the left side L is machined on the basis of the advancing direction (arrow) of the tool M, when the groove 22 is inclined to the left as shown in Fig. 10, the value of C is increased in the offset direction . On the other hand, when the right side R is machined on the basis of the advancing direction (arrow) of the tool M, the value C is decreased in the offset direction when tilted to the right as shown in FIG.

Meanwhile, since the present embodiment is based on an AC-type 5-axis CNC machining machine, if the BC-type 5-axis CNC machining machine is increased or decreased in the same manner, The value of A may be increased or decreased.

As described above, according to the present invention, the inclination angles of both sides of the mountain 24 can be gently formed in the straight section and the curved section of the groove 22 of the drum cam 20, so that the width of the groove 22 is widened, Backlash can be removed between the roller (12) and the mountain (24) of the roller (10).

10: Middle 12: Roller
12a: No. 1 roller 12b: No. 2 roller
12c: No. 3 roller 12d: No. 4 roller
20: drum cam 22: groove
24: Mount 100: Roller gear cam

Claims (4)

A method of machining a roller gear cam using a 5-axis CNC machining machine comprising an angle line definition step, a roughing machining definition step and a finishing machining definition step,
The step of defining the angle line is performed such that data is extracted so that the angle of the inclined surfaces on both sides of the ridge 24 of the drum cam 20 is formed larger than the angle of the roller 12 of the follower 10, Method of machining roller gear cam using machine.
The method according to claim 1,
The rotation angle? Of the drum cam 20 and the rotation angle? Of the follower 10 are defined by the following data 1 with respect to one groove 22 of the drum cam 20,
The rotation angle? Of the drum cam 20 and the rotation angle? Of the follower 10 are defined as data 4 below with reference to another groove 22 adjacent to the groove 22 A method of machining a roller gear cam using a 5-axis CNC machining machine.
[Data 1]
(? ₁ ,? ₁ ), (? ₂ ,? ₂ ), (? ₃ ,? ₃ ) ... (? _n ,? _n )
[Data 4]
(? ₁ ,? ₁ + 60? +?), (? ₂ ,? ₂ + 60? +?), ... (? _n ,? _n + 60 ° +?) (?> 0)
Where a is a micro angle.
A method of machining a roller gear cam using a 5-axis CNC machining machine comprising an angle line definition step, a roughing machining definition step and a finishing machining definition step,
Wherein the finishing processing is performed so that the width of the groove (22) of the drum cam (20) in the curve section of the groove (22) of the drum cam (20) Method of machining roller gear cam using machine.
The method of claim 3,
Wherein the machining position data of the 5-axis CNC machining machine is defined by the following data 9, and the C value of the data 9 is increased or decreased.
[Data 9]
(X _1i +? N _x , Y _1i +? N _y , Z _1i , A _1i , C _1i ), ... X _ni +? N _x , Y _ni +? N _y , Z _ni , A _ni , C _ni )
(X _{1i -?} N _x , Y _{1i -?} N _y , Z _1i , A _1i , C _1i ), ... , (X _{ni -?} N _x , Y _{ni -?} N _y , Z _ni , A _ni , C _ni )
Where N _x and N _y are the X component and the Y component of the normal unit vector at any position of the curve made up of the groove 22 of the drum cam 20, Tool diameter) / 2.

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