Cam groove, machining apparatus for the same, and machining method for the same.

Abstract

Cam groove machining is performed using general-purpose machining equipment. [Solution] A workpiece 100, which is a roller gear cam that rotates around a rotation axis XR, has a cam groove formed on its oval surface 110. The cam groove is machined by a ball end mill 200 that rotates around a rotation axis XB. The tip of the ball end mill 200 is a hemispherical surface 210, and the hemispherical surface 210 contacts the oval surface 110. Therefore, even if contact is made from a direction other than the normal direction of the oval surface 110, contact is made at a single point. The normal direction of the oval surface 110 at the contact position CP is FR, and the contact direction of the ball end mill 200 is FB. The opposite direction of FR and FB do not coincide, but since contact occurs at position CP of the hemispherical surface 210 of the ball end mill 200, the cam groove can be machined well.

Description

Technical Field

[0001] The present invention relates to a cam groove, its processing apparatus, and its processing method, and more particularly, to an improvement in cam groove processing technology suitable for processing a cam groove on a curved surface such as a drum shape.

Background Art

[0002] As a conventional cam groove processing apparatus, for example, there is a "ribbed drum cam generation processing apparatus" described in Patent Document 1 below. This is for the purpose of generating and processing a ribbed drum cam having a shape that cannot be processed by a general-purpose machine. While rotating an end mill by a milling unit, the drum-shaped processing surface of the material is processed. The end mill rotates by following the apparatus along a template showing the shape of the cam groove to be processed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above-described background art, the end mill is controlled to follow the shape of the template and is driven to rotate, and it is necessary to prepare a template corresponding to the processing shape. In addition, the mechanism for driving the rotation is complicated, and it would be convenient if various-shaped cam grooves could be formed using a general-purpose processing apparatus.

[0005] The present invention has been made in view of such a point, and its object is to perform cam groove processing using a general-purpose processing apparatus. Another object is to easily change the depth and width of the cam groove.

Means for Solving the Problems

[0006] The present invention is characterized by using a ball end mill to machine a cam groove and moving the ball end mill parallel to its axis of rotation to machine the cam groove. In one of the main embodiments, the depth or width of the cam groove is adjusted by moving the ball end mill back and forth in the direction of the axis of rotation of the rotation drive. This back and forth movement of the ball end mill is also applicable when machining the cam groove by rotating the ball end mill.

[0007] By using a ball end mill, machining can be performed from directions different from the normal direction of the drum-shaped surface, for example. Furthermore, by moving the ball end mill back and forth in the direction of the rotation axis to adjust the groove depth and groove width, a retaining portion can be formed in the cam groove, making pre-pressure control easy. The aforementioned and other objectives, features, and advantages of the present invention will become clear from the following detailed description and accompanying drawings. [Effects of the Invention]

[0008] According to the present invention, since the cam groove is machined and formed on the workpiece surface using a ball end mill, it is only necessary to move the ball end mill in parallel, making it possible to use general-purpose machining equipment. Furthermore, the depth and width of the cam groove can be easily adjusted by moving the ball end mill forward and backward. [Brief explanation of the drawing]

[0009] [Figure 1] The main parts of Embodiment 1 of the present invention are shown. [Figure 2] (A) shows the processing in Example 1, and (B) shows the processing in Example 3. [Figure 3] An example of machining a cam groove according to the above embodiment is shown. [Figure 4] The main parts of Embodiment 2 of the present invention are shown. [Figure 5] An example of machining a cam groove according to the above embodiment 2 is shown. [Modes for carrying out the invention]

[0010] The best mode for carrying out the present invention will be described in detail below based on examples. [Examples]

[0011] Figure 1 shows the main cross-section of an embodiment in which the present invention is applied to the machining of cam grooves in roller gear cams used in ATCs (Automatic Tool Changers) and automatic transfer equipment. Figure (A) shows the state before machining, and (B) shows a magnified view of the state during machining. In these figures, the workpiece 100, which is a roller gear cam that rotates around the rotation axis XR, has cam grooves formed on its oval surface 110. In this embodiment, the cam grooves are machined by a ball end mill 200 that rotates around the rotation axis XB. As shown in Figure (B), the tip portion of the ball end mill 200 is a hemispherical surface 210, and the hemispherical surface 210 contacts the oval surface 110. Therefore, even if contact is made from a direction other than the normal direction of the oval surface 110, contact is made at a single point. In the illustrated example, the normal direction of the oval surface 110 at the contact position CP is FR, and the contact direction of the ball end mill 200 is FB. Although the reverse direction of FR and FB do not coincide, contact occurs at position CP of the hemispherical surface 210 of the ball end mill 200, allowing for good machining of the cam groove.

[0012] The ball end mill 200 is driven to rotate around the rotation axis XB by the rotation mechanism 250, can move forward and backward in the direction of the rotation axis XB by the forward / backward mechanism 260, and can move parallel to the direction F2A, which is perpendicular to the direction of the rotation axis XB, by the parallel movement mechanism 270. Depending on the shape of the machined surface of the workpiece 100 and the shape of the cam groove to be machined, the forward / backward mechanism 260 may not be necessary. Alternatively, the workpiece 100 may be moved forward and backward or parallel to the ball end mill 200.

[0013] Figure 2(A) shows the process of sequentially machining the cam groove 120 with a ball end mill 200. The ball end mill 200 moves parallel to the direction F2A, which is perpendicular to the direction of its rotation axis XB. As a result, the contact position CP of the hemispherical surface 210 with respect to the drum-shaped surface 110 changes, but the machining is performed well. Figure 2(B) will be discussed later.

[0014] Figure 3(A) shows a specific example of ball table arc interpolation machining, in which a cam groove is machined on the drum-shaped surface 110 of a workpiece 100 using a ball end mill 200. First, a relief cut 122 is applied to the drum-shaped surface 110, and then the cam groove 120 is formed with the ball end mill 200. Since grinding cannot be done at the tip of the ball end mill 200, a relief cut 122 is applied to this part. Then, by performing cam groove machining with the ball end mill 200 while rotating the workpiece 100, a cam groove 120 can be formed, for example, as shown in Figure 3(B) when the drum-shaped surface 110 is unfolded. In the figure, A is continuous on the drum-shaped surface 110. A magnified view of a part of the cam groove 120 is shown in Figure 5(A), which will be described later.

[0015] The workpiece 100 on which the cam groove 120 is formed in this manner can be applied, for example, to a worm gear 310 and a worm wheel 320 of a cam mechanism 300 as shown in Figure (C) (see Japanese Patent Publication No. 2008-133957), where the balls 322 on the circumferential surface of the worm wheel 320 fit into the cam groove 312 of the worm gear 310. The cam mechanism 400 in Figure (D) is an example where the position of the balls 422 of the worm wheel 420 relative to the worm gear 410 is different, with the balls 422 being provided on the side surface of the worm wheel 420. Therefore, on the side surface of the worm wheel 420, the balls 422 fit into the cam groove 412 of the worm gear 410.

[0016] As described above, according to this embodiment, since the cam groove is machined and formed on the drum-shaped surface 110 of the workpiece 100 using a ball end mill 200, it is only necessary to move the ball end mill 200 in a direction perpendicular to the rotation axis, making it possible to use a general-purpose machining tool.

Embodiment

[0017] Next, referring to FIGS. 4 and 5, Embodiment 2 of the present invention will be described. In this embodiment, the depth of the cam groove 120 on the drum surface 110 of the workpiece 100 is adjusted by moving or sliding the ball end mill 200 in the direction of the rotation axis XB. FIG. 4 shows the state during cam groove machining. At the position of the ball end mill 200 in FIG. 4(A), the cam groove 120A has a central depth DA (excluding the relief machining) from the drum surface 110 and a groove width of RA. On the other hand, as shown in FIG. 4(B), when the ball end mill 200 is moved in the direction of arrow F4B for machining, the depth of the cam groove 120B becomes shallower like DB and the groove width becomes narrower like RB. That is, DA>DB and RA>RB.

[0018] Thus, by advancing and retreating the ball end mill 200 in the direction of the rotation axis, the depth and width of the cam groove 120 can be adjusted. For example, in the example of the cam groove 120 in FIG. 5(A), the portion of the cam groove 120P and the cam groove 120Q continuous thereto (see 120PQ in FIG. 3(B)) has a shallower cam groove depth and a narrower cam groove width as shown in FIG. 5(B) compared to the portions of the other cam grooves 120.

[0019] Normally, the cam groove 120 is machined so that the machining depth and machining width are constant, but the depth is machined shallower and the width is machined narrower during the stop (the range of 120PQ in FIG. 3(B)). By doing so, as shown in FIGS. 3(C) and (D), when the balls 322 and 422 move in the normal cam groove 120, the balls 322 and 422 move lightly, but as they get closer to the stop, the balls 322 and 422 are pushed by the cam groove 120PQ and the applied pressure starts to be applied. Since the applied pressure is applied only during the stop, the backlash during the stop can be eliminated and the rigidity can be improved.

[0020] Thus, according to this embodiment, by advancing and retreating the ball end mill 200 in the axial direction of rotation, the depth and groove width of the cam groove 120 can be easily adjusted as required. Thereby, the following effects can be obtained. a, Pressure application management can be easily performed using a ball cam. Usually, since the same pressure is applied to the same cam groove in the same manner, skill is required. b, Processing is simplified in dimension management. c, Assembly is simplified. d, Backlash during stopping can be eliminated. e, The rigidity during stopping can be increased. f, Since the pressure is applied only during stopping, accuracy, rigidity, and backlash are stabilized. g, Adjustment during assembly becomes dimension management, so it is simplified. In particular, adjustment processing for shallowing the cam groove 120 at the stop point of the cam can be easily performed. The distance within the stop range and the groove depth can be arbitrarily set, and pressure application management can be easily performed using a ball cam.

Example

[0021] Next, referring also to Fig. 2(B), Example 3 of the present invention will be described. In the above-described example, the ball end mill 200 is moved parallel to the axial direction of rotation, but in this example, when the ball end mill 900 is swiveled as shown in Fig. 2(B), the movement in the advancing and retreating direction of Example 2 described above is performed. In this example, the machining direction of the hemispherical surface 910 of the ball end mill 900 coincides with the normal direction of the drum-shaped surface 110, and a swivel mechanism is provided instead of the parallel movement mechanism 270 shown in Fig. 1, and thereby the ball end mill 900 is swiveled along the drum-shaped surface 110 in the direction of arrow F2B to perform machining of the cam groove 920. Also in this example, by advancing and retreating the ball end mill 900 in the direction of the axis of rotation, the same effects as those in the examples of Figs. 4 and 5 described above can be obtained. <00001​​​(1) The shapes and dimensions of each part shown in the above embodiment, in particular the shape of the cam groove, are examples and can be modified in design to perform similar functions. (2) In the above embodiment, the ball end mills 200 and 900 were moved relative to the workpiece 100, but the movement of the two is relative, and the workpiece 100 may be moved relative to the ball end mills 200 and 900. (3) The present invention is preferably applied to machined surfaces of various shapes, although a drum-shaped machined surface of the cam groove is a preferred example. (4) The present invention is applicable to the machining of cam grooves used in various machine tools, such as machining centers, CNC (computer numerical control) machines, milling machines, lathes, and laser cutting machines. [Industrial applicability]

[0023] According to the present invention, since the cam groove is machined and formed on the workpiece surface using a ball end mill, it is only necessary to move the ball end mill in parallel, making it possible to use general-purpose machining equipment. Furthermore, the depth and width of the cam groove can be easily adjusted by moving the ball end mill forward and backward, making it suitable for various types of cam groove machining. [Explanation of Symbols]

[0024] 100: Workpiece 110: Tympanic surface 120, 120A, 120B, 120P, 120Q: Cam groove 122: Relief processing 200: Ball end mill 210: Hemisphere 250: Rotation mechanism 260:Advance / retreat mechanism 270: Translation mechanism 300, 400: Cam mechanism 310,410: Worm gear 312,412: Cam groove 320,420: Worm wheel 322,422: Ball 900: Ball end mill 910: Hemisphere 920: Cam groove

Claims

1. A cam groove machining apparatus for machining a cam groove on the machined surface of a workpiece, A rotating mechanism that drives a ball end mill to rotate. A parallel movement mechanism moves the ball end mill parallel to the axis of rotation in the rotation mechanism. It is equipped with, A cam groove machining apparatus characterized by machining the cam groove using the ball end mill.

2. The ball end mill is equipped with a reciprocating mechanism that moves it back and forth in the direction of the rotational axis of the rotation drive, The cam groove machining apparatus according to claim 1, characterized in that the depth or width of the cam groove is adjusted by moving the ball end mill forward and backward in the direction of the rotation axis using this forward and backward mechanism.

3. A cam groove machining apparatus for machining a cam groove on the machined surface of a workpiece, A rotating mechanism that drives a ball end mill to rotate. A reciprocating mechanism that moves the ball end mill back and forth in the direction of the rotational axis of the rotation drive, A pivoting mechanism for rotating the rotation axis of the ball end mill, It is equipped with, A cam groove machining apparatus characterized in that, when machining the cam groove with the ball end mill, the depth or width of the cam groove is adjusted by moving the ball end mill back and forth in the rotational axis direction using the advancement and retraction mechanism.

4. The cam groove machining apparatus according to claim 1 or 3, characterized in that the machined surface is a drum-shaped surface.

5. A cam groove machining method, comprising machining a cam groove using a cam groove machining apparatus according to claim 1 or 3, Before machining the aforementioned cam groove, relief machining is performed along the machining area of ​​the cam groove. Next, a method for machining a cam groove, characterized by machining the cam groove using the ball end mill.

6. A cam groove characterized by being formed by a cam groove machining apparatus according to claim 1 or 3.

7. A cam groove formed by a cam groove machining apparatus according to claim 2 or 3, A cam groove characterized by having a retaining portion with adjustable depth or groove width.

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