JP2009039822A - Cam-type tool changer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cam type tool changer easily carrying out centering of a camshaft and a rotating shaft of an encoder with high accuracy and shortening the axial length of a connection part between the camshaft and the rotating shaft of the encoder. <P>SOLUTION: The cam type tool changer 10 is provided with the encoder 30 connected to the camshaft 12 to detect the rotating angle of the camshaft 12, wherein the camshaft 12 is formed with a recessed fitting part 12 centering on an axis C1, and the rotating shaft 31 of the encoder 30 is formed with a protrusive fitting part 31b centering on an axis C2 and fitted in the recessed fitting part 12. Since the camshaft 12 and the rotating shaft 31 of the encoder 30 are easily centered with high accuracy, an assembly work time of the cam-type tool changer is shortened, and since the axial length of the connection part between the camshaft 12 and the rotating shaft 31 of the encoder 30 is shortened, a protective cover 40 for protecting the encoder 30 from chips and cutting oil can be provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cam type tool changer for a machine tool, and more particularly to a cam type tool changer provided with an encoder for detecting a rotation angle of a cam shaft.

  In a machining center or the like, an automatic tool changer (ATC: Automatic Tool Changer) is used to automatically change a tool, and a cam-type tool changer is also known. The cam-type tool changer has a cam shaft that is rotated by a motor, and the cam formed on the cam shaft performs a turning motion and a reciprocating linear motion of the changer arm.

FIG. 11 shows an example of a conventional cam type tool changer. As shown in FIG. 11, a connecting shaft 1 a extending in the axial direction is formed at the end of the camshaft 1. An encoder 4 for detecting the rotation angle of the camshaft 1 is attached to a housing 3 that holds a bearing 2 that rotatably supports the camshaft 1. The rotating shaft 4a of the encoder 4 is connected to the connecting shaft 1a of the cam shaft 1 through the coupling 5, and the cam shaft 1 is transmitted to the rotating shaft 4a of the encoder 4 by transmitting the movement of the cam shaft 1 in the rotating direction. The rotation angle of the shaft 1 is detected. The following Patent Document 1 is known as an example of a cam type tool changer having an encoder that detects the rotation angle of a cam shaft.
JP 2001-232532 A

  However, in the conventional cam type tool changer shown in FIG. 11, since the cam shaft 1 and the rotary shaft 4a of the encoder 4 are connected using the coupling 5, the cam shaft 1 and the rotary shaft 4a of the encoder 4 are assembled in the assembly work. There is a problem that it is necessary to perform centering with high accuracy, and it takes time for the centering work. Further, when the coupling 5 is used, the connecting portion between the cam shaft 1 and the rotary shaft 4a of the encoder 4 becomes long, so the encoder 4 protrudes from the side surface of the housing 3 by a distance L3, and the encoder 4 is cut. There arises a problem that a protective cover for protecting from dust and cutting oil cannot be provided. That is, the cam type tool changer has a limitation in the external dimensions due to the relationship with the attachment to the machine tool, and in the device using the coupling 5, the encoder 4 protrudes greatly outward. It is difficult to secure a space for providing a protective cover. Therefore, in order to secure the installation space for the protective cover, the axial length of the connecting portion of the rotating shaft 4a of the camshaft 1 and the encoder 4 is shortened, and from the side surface of the housing 3 to the outer end of the encoder 4 It is necessary to shorten the distance L3.

  Therefore, the present invention can perform centering of the cam shaft and the rotary shaft of the encoder with high accuracy and easily and reduce the axial length of the connecting portion between the cam shaft and the rotary shaft of the encoder. It is an object of the present invention to provide a cam type tool changer capable of performing the above.

  In order to achieve the above object, the invention according to claim 1 is a cam type tool changer including an encoder connected to a cam shaft and detecting a rotation angle of the cam shaft. Forming a concave fitting portion, and forming a convex fitting portion that fits with the concave fitting portion around the axis of the rotation axis of the encoder, and the concave fitting portion and the convex fitting portion The cam-type tool changer is characterized in that the encoder is coaxially disposed on the cam shaft in a state in which is fitted.

  According to the present invention, the cam shaft and the rotary shaft of the encoder can be centered with high accuracy and easily by simply fitting the concave fitting portion and the convex fitting portion. Further, since the concave fitting portion is formed on the cam shaft side, the cam shaft can be connected to the encoder without extending the cam shaft in the axial direction, and the length of the connecting portion in the axial direction is shortened.

  According to a second aspect of the present invention, in the cam type tool changer according to the first aspect, the camshaft and the rotating shaft are connected to each other, and interlocking means for rotating the rotating shaft in conjunction with the camshaft is provided. It is characterized by providing.

  According to a third aspect of the present invention, in the cam type tool changer according to the second aspect, the interlocking means includes a connection pin that connects the cam shaft and the rotation shaft outside the shaft center, and the connection The rotating shaft rotates in conjunction with the cam shaft via a pin.

  According to the first aspect of the present invention, the cam shaft and the rotary shaft of the encoder can be easily centered, so that the assembly time of the cam type tool changer can be shortened. In addition, since the axial length of the connecting portion between the camshaft and the encoder can be shortened, a space for providing a protective cover for the encoder can be secured. Can be protected from.

  According to the second aspect of the present invention, since the encoder rotates in conjunction with the cam shaft by the interlocking means, the rotation angle of the cam shaft can be reliably detected by the encoder.

  According to the invention of claim 3, since the camshaft and the rotating shaft are connected using the connecting pin, the structure of the connecting portion can be simplified compared to a fitting structure using a spline or the like, Manufacture is easy.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 to 7 show Embodiment 1 of the present invention. 2 and 3, reference numeral 10 denotes a cam type tool changer. The cam type tool changer 10 mainly includes a housing 11, a cam shaft 12, a cam 15, and a changer arm 18. The housing 11 is attached to the base 20. A cam shaft 12 is accommodated in the housing 11. The cam shaft 12 is rotatably supported by the housing 11 via bearings 24 disposed at both ends in the axial direction. A worm wheel 13 for rotating the cam shaft 12 around the axis is attached to an intermediate portion in the axial direction of the cam shaft 12. A worm gear 14 for rotating the worm wheel 13 is disposed below the cam shaft 12. The worm gear 14 is attached to the output shaft of the motor 19 fixed to the housing 11 and meshes with a part of the outer peripheral portion of the worm wheel 13. A cam 15 is attached to the cam shaft 12 adjacent to the worm wheel 13. A key groove 12 d extending in the axial direction is formed in the cam shaft 12, and a key 26 for fixing the worm wheel 13 and the cam 15 to the cam shaft 12 is attached to the key groove 12 d. Thus, the worm wheel 13 and the cam 15 are fixed at predetermined positions in the direction around the axis of the cam shaft 12 and are rotated in conjunction with the cam shaft 12.

  A shaft holding portion 16 is formed on the upper portion of the housing 11. The shaft holding portion 16 holds an output shaft 17 that can move both in the axial direction and in the direction around the axis. A changer arm 18 extending in the horizontal direction is attached to the tip of the output shaft 17. The output shaft 17 is interlocked with the cam 15, and can move in the axial direction and in the direction around the axis depending on the rotation angle of the cam 15. At both ends of the changer arm 18, a holding portion 18a and a holding portion 18b for holding a tool holder (not shown) are formed. A safety cover 22 fixed to the base 20 is disposed on the outer periphery of the changer arm 18.

  An annular encoder mounting base 23 is mounted on the housing 11. A male screw 23 a is formed on the outer peripheral portion of the encoder mounting base 23, and the male screw 23 a is screwed into the housing 11. The bearing 24 that supports the end of the camshaft 12 is positioned inside the encoder mounting base 23. The outer ring of the bearing 24 is fitted to one of the inner sides of the encoder mounting base 23 and is held in the housing 11 via the encoder mounting base 23. An oil seal 25 that is in sliding contact with the outer peripheral surface of the shaft end portion of the cam shaft 12 is attached to the other inner side of the encoder mounting base 23.

  As shown in FIGS. 6 and 7, the distal end portion 12 a of the cam shaft 12 is formed with a concave fitting portion 12 b centering on the axis C <b> 1 of the cam shaft 12. The concave fitting portion 12b is formed by cutting the tip portion 12a of the cam shaft 12 into a circular shape, and is processed with high accuracy because it is used for centering with the encoder 30 described later. As shown in FIG. 7, a fixing hole 12c extending in the axial direction from the bottom surface of the concave fitting portion 12b is formed in the distal end portion 12a. The fixing hole 12c is disposed at a position away from the axis C1, and is inscribed in the inner peripheral surface of the concave fitting portion 12b. The fixing hole 12c is for press-fitting a connecting pin 35 as an interlocking means for interlocking with the camshaft 12 and the rotary shaft 31 of the encoder 30, and has an inner diameter slightly smaller than the outer diameter of the connecting pin 35. ing. As shown in FIG. 6, the fixing hole 12c is located on an axis X2 orthogonal to the axis Y2 connecting the center of the key groove 12d and the axis C1 of the cam shaft 12. That is, the angle θ2 formed by the axis Y2 passing through the center of the key groove 12d and the axis X2 passing through the fixing hole 12c is 90 degrees. A center hole 12h for lathe machining is formed on the axis C1 of the tip 12a of the cam shaft 12.

  As shown in FIG. 1, an encoder 30 that electrically detects the rotation angle of the camshaft 12 is attached to one side of the encoder mounting base 23. The encoder 30 is composed of an absolute type encoder that detects an absolute position. In the cam type tool changer 10, in order to accurately control the operation of the changer arm 18, it is necessary to grasp the movement of the camshaft 12 with high accuracy. Therefore, the encoder 30 detects the rotation angle of the camshaft 12. Is done. The encoder 30 is fixed to the encoder mounting base 23 with a bolt 37 through a fixing bracket 36.

  The rotary shaft 31 of the encoder 30 extends toward the cam shaft 12 side. As shown in FIGS. 4 and 5, a convex fitting portion 31 b centering on the axis C <b> 2 of the rotating shaft 31 is formed at the tip portion 31 a of the rotating shaft 31. The convex fitting portion 31b has a cylindrical shape and is processed with high accuracy because it is used for centering with the cam shaft 12. The outer diameter of the convex fitting portion 31 b is formed slightly smaller than the inner diameter of the concave fitting portion 12 b of the cam shaft 12. A concave fitting portion 31c is formed at the tip portion 31a of the rotating shaft 31 and extends in the axial direction from the shaft end about the shaft center C2. The concave fitting portion 31c has a circular hole shape and is not used for fitting in the first embodiment, but is used for a fitting structure in a second embodiment to be described later. In the first embodiment, the concave fitting portion 31 c functions as a reduction hole of the rotating shaft 31.

  An engaging groove 31d extending in the axial direction from the shaft end is formed at the tip 31a of the rotating shaft 31. As shown in FIG. 5, the engaging groove 31 d is a groove penetrating between the convex fitting portion 31 b and the concave fitting portion 31 c, and the groove width is formed slightly larger than the outer diameter of the connecting pin 35. Has been. The engagement groove 31d is located on the axis line X1 orthogonal to the axis line Y1 connecting the center of the cable 32 and the axis C2 of the rotation shaft 31. That is, the angle θ1 formed by the axis X1 passing through the engagement groove 31d and the axis Y1 passing through the center of the cable 32 is 90 degrees. The position of the engagement groove 31d in FIG. 5 indicates the case where the rotation angle of the cam shaft 12 is 0 degree. Thus, in the encoder 30, the position of the engagement groove 31d (angle θ1) with respect to the axis Y1 passing through the center of the cable 32 is defined. The encoder 30 is an absolute type encoder, and the absolute This is because it is necessary to detect the position (angle). In the case of an increment type encoder, the position of the engagement groove 31d is not particularly problematic because the detection start position can be freely set by reset.

  As shown in FIG. 3, a cover 38 that extends obliquely downward from the lower portion of the shaft holding portion 16 and covers one side of the housing 11 is provided outside the housing 11. A protective cover 40 is provided between the cover 38 and the encoder 30 to cover the opposite side of the encoder 30 from the rotating shaft 31 side. Thereby, the encoder 30 is protected from cutting powder and cutting oil entering from the cover 38 side.

  Next, the installation work procedure and the operation of the encoder 30 according to the first embodiment will be described.

  As shown in FIG. 1, first, with the camshaft 12 stopped at a predetermined position, the connecting pin 35 is inserted into the fixing hole 12c of the camshaft 12, and one of the connecting pins 35 is press-fitted into the fixing hole 12c. The other of the connecting pins 35 press-fitted into the camshaft 12 protrudes from the fixing hole 12c, and is in a state of being able to engage with the rotating shaft 31 of the encoder 30. Here, since the structure in which the connecting pin 30 is press-fitted into the cam shaft 12 instead of the rotating shaft 31 of the encoder 30 is adopted, there is no need to increase the shaft diameter of the rotating shaft 31 of the encoder 30, and the encoder 30 is small-sized. Things can be used. Since the fixing hole 12c is formed at the bottom of the concave fitting portion 12b as shown in FIG. 7, there is no protrusion on the portion of the cam shaft 12 into which the connecting pin 35 is press-fitted, and the cam shaft at the time of press-fitting work. Interference between 12 and the press-fitting tool can be avoided. Thereby, the press-fitting work of the connecting pin 35 is facilitated and the cam shaft 12 can be prevented from being damaged.

  Next, the encoder 30 is pushed toward the camshaft 12 in a state where the rotary shaft 31 is disposed so as to face the shaft end of the camshaft 12. The inner diameter of the concave fitting portion 12b of the cam shaft 12 is set to be slightly larger than the outer diameter of the convex fitting portion 31b of the encoder 30, and has a so-called gap fitting structure. By projecting toward the shaft 12, the convex fitting part 31b smoothly enters the concave fitting part 12b. That is, when the convex fitting portion 31b and the concave fitting portion 12b are fitted, a minute gap exists in the fitting portion, so that the concave fitting portion 12b and the convex fitting are formed with a small force. The fitting with the part 31b is performed.

  In a state where the mounting surface of the encoder 30 is in contact with the encoder mounting base 23 by pressing the encoder 30 toward the camshaft 12, the connecting pin 35 enters the engaging groove 31d. When the connecting pin 35 enters the engaging groove 31d, the cam shaft 12 and the rotary shaft 31 of the encoder 30 are connected to each other around the shaft center via the connecting pin 35, and the rotary shaft 31 of the encoder 30 is connected to the cam shaft 12. It will rotate in conjunction with. When the connection between the cam shaft 12 and the rotary shaft 31 is completed, the bolt 37 is tightened, and the encoder 30 is fixed to the encoder mounting base 23 via the support fitting 36. In this state, as shown in FIG. 1, since the shaft center C2 of the encoder 30 is coaxially disposed with respect to the shaft center C1 of the camshaft 12, there is no runout and the encoder 30 is smoothly moved by the camshaft 12. Can be rotated. Further, since the cam shaft 12 and the encoder 31 are connected by the connecting pin 35, the structure of the connecting portion can be simplified as compared with the fitting structure using the spline, and the manufacturing of the connecting portion is facilitated.

  As described above, the fitting of the concave fitting portion 12b and the convex fitting portion 31b automatically centers the rotating shaft 31 of the encoder 30 with respect to the camshaft 12, so that the centering operation is facilitated. The assembly time of the cam type tool changer 10 can be shortened. Further, since the cam shaft 12 is formed with the concave fitting portion 12b, the cam shaft 12 can be connected to the encoder 30 without extending in the axial direction, and therefore, from the side surface of the housing 11 to the outer end of the encoder 30. This distance L1 is shorter than the distance L3 in the conventional apparatus of FIG. Therefore, as shown in FIG. 3, a space for providing the protective cover 40 of the encoder 30 can be secured, and the encoder 30 can be protected from cutting powder and cutting oil.

(Embodiment 2)
8 to 10 show a second embodiment of the present invention. The second embodiment is different from the first embodiment only in the fitting structure of the camshaft and the encoder, and the other configurations are the same as those in the first embodiment. Therefore, the same reference numerals as those in the first embodiment are given to the corresponding parts. Therefore, the description of the corresponding part is omitted. In the second embodiment, only the shape of the end of the cam shaft 12 is different from the first embodiment, and the same encoder 30 as that of the first embodiment is used.

  9 and 10, a convex fitting portion 12 f centering on the axis C <b> 1 of the cam shaft 12 is formed at the distal end portion 12 e of the cam shaft 12. The convex fitting portion 12 f is formed by cutting the tip end portion 12 e of the cam shaft 12 into a cylindrical shape, and is processed with high accuracy because it is used for centering with the encoder 30. The cam shaft 12 is formed with a fixing hole 12i extending in the axial direction from the base portion of the convex fitting portion 12f. The fixing hole 12i has an inner diameter slightly smaller than the outer diameter of the connecting pin 35, and one of the connecting pins 35 can be press-fitted. The convex fitting part 12f is formed with a cut part 12g partly cut in the axial direction. The fixing hole 12 i is formed at a position adjacent to the cut portion 12 g in the cam shaft 12. The fixing hole 12i is located on the axis line X4 orthogonal to the axis line X4 connecting the center of the keyway 12d and the axis C1 of the cam shaft 12. That is, the angle θ4 formed by the axis Y4 passing through the key groove 12d and the axis X4 passing through the fixing hole 12i is 90 degrees.

  Next, an installation work procedure of the encoder 30 and its operation in Embodiment 2 of the present invention will be described.

  As shown in FIG. 8, with the cam shaft 12 stopped at a predetermined position, the connecting pin 35 is inserted into the fixing hole 12i of the cam shaft 12, and the connecting pin 35 is press-fitted into the fixing hole 12i. When the press-fitting of the connecting pin 35 is completed, the encoder 30 is pushed out toward the cam shaft 12 in a state where the rotary shaft 31 is disposed so as to face the shaft end of the cam shaft 12. Since the outer diameter of the convex fitting portion 12f of the cam shaft 12 is set to be slightly smaller than the inner diameter of the concave fitting portion 31c of the encoder 30, the convex shape is obtained by pushing the encoder 30 to the cam shaft 12 side. The shape fitting portion 12f smoothly enters the concave fitting portion 31c. That is, when the convex fitting portion 12f and the concave fitting portion 31c are fitted, there is a minute gap in the fitting portion, so that the convex fitting portion 12f and the concave fitting are formed with a small force. The fitting with the part 31c is performed.

  The convex fitting portion 12f is formed around the axis C1 of the cam shaft 12, and the concave fitting portion 31c is formed around the axis C2 of the rotating shaft 31 of the encoder 30, so that the convex shape By the fitting of the fitting portion 12f and the concave fitting portion 31c, the shaft center C1 and the shaft center C2 are located on the same line. When the encoder 30 is pressed against the camshaft 12 and the attachment surface of the encoder 30 is in contact with the encoder attachment base 23, the connecting pin 35 enters the engagement groove 31d. When the connecting pin 35 enters the engaging groove 31d, the cam shaft 12 and the rotary shaft 31 of the encoder 30 are connected to each other around the shaft center via the connecting pin 35, and the rotary shaft 31 of the encoder 30 is connected to the cam shaft 12. It will rotate in conjunction with. In this state, the distance L2 from the side surface of the housing 11 to the outer end of the encoder 30 is shorter than the distance L3 of the conventional device in FIG.

  Thus, by forming both the convex fitting part 31b and the concave fitting part 31c in the rotating shaft 31 of the encoder 30, the encoder 30 can be connected to either of the camshafts 12 of the first and second embodiments ( It is possible to use the encoder 30 as well, and the encoder 30 can be shared.

  As described above, the embodiments of the present invention have been described in detail, but the specific configuration is not limited to these embodiments, and even if there is a design change or the like without departing from the gist of the present invention, It is included in this invention. In each of the above embodiments, the connecting pin 35 is used as the interlocking means for interlocking the camshaft 12 and the rotating shaft 31 of the encoder 30. For example, the cross-sectional shapes of the convex fitting portion and the concave fitting portion are D-shaped. A fitting structure (a fitting structure with a convex fitting part having a D-shaped cross-sectional shape by cutting off a part of the outer periphery of a shaft having a circular cross-section and a concave fitting part having a D-shaped cross-sectional shape), A configuration using a fitting structure such as a spline as the interlocking unit may be used. In addition, the encoder 30 means an encoder having a function of electrically detecting the rotation angle of the camshaft 12 and may be of any kind.

It is sectional drawing which shows the connection state of the cam shaft and encoder in the cam type tool change apparatus concerning Embodiment 1 of this invention. It is a front view of the cam type tool change apparatus of FIG. It is a side view (partial sectional view) of the cam type tool changer of FIG. It is a front view (partial sectional view) of an encoder in the cam type tool changer of FIG. It is a top view of the encoder of FIG. It is a front view of the camshaft end part in the cam type tool changer of FIG. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which shows the connection state of the cam shaft and encoder in the cam type tool change apparatus concerning Embodiment 2 of this invention. It is a front view of the camshaft end part in the cam type tool changer of FIG. It is sectional drawing which follows the BB line of FIG. It is sectional drawing which shows the connection state of the cam shaft and encoder in the conventional cam type tool change apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cam type tool changer 12 Cam shaft 12b Concave fitting part 12c Fixing hole 12d Key groove 12f Convex fitting part 12i Fixing hole 15 Cam 18 Changer arm 23 Base for encoder attachment 30 Encoder 31b Convex fitting part 31c Concave fitting Joint portion 31d Engaging groove 35 Connecting pin C1 Shaft center of cam shaft C2 Shaft center of encoder

Claims (3)

  In a cam type tool changer having an encoder connected to a cam shaft and detecting a rotation angle of the cam shaft, a concave fitting portion having an axis center is formed on the cam shaft, and a shaft is disposed on the rotation shaft of the encoder. A convex fitting portion is formed to fit with the concave fitting portion around the center, and the encoder is coaxially connected to the cam shaft in a state where the concave fitting portion and the convex fitting portion are fitted. A cam type tool changer characterized by being arranged.   The cam type tool changer according to claim 1, further comprising interlocking means for connecting the cam shaft and the rotation shaft to rotate the rotation shaft in conjunction with the cam shaft.   The interlocking means is provided with a connecting pin that connects the cam shaft and the rotating shaft outside the shaft center, and the rotating shaft rotates in conjunction with the cam shaft via the connecting pin. The cam type tool changer according to claim 2.

Images