TWI869979B - Tool changing device for processing machine - Google Patents

Abstract

A tool changing device for a processing machine includes a tool changing arm connected to a fixed machine base, and a transmission mechanism drives the tool changing arm to swing. The transmission mechanism includes a displacement cam, a follower and a rotating shaft. The displacement cam surface has a curved groove, the follower has a protrusion embedded in the curved groove, and the follower is connected to the rotating shaft in an interlocking manner. The rotating shaft is connected to the tool changing arm. Thereby, when the displacement cam rotates, the follower is driven to translate, and the moving follower drives the rotating shaft to rotate and drives the tool changing arm to accurately swing and position between two fixed points.

Description

Tool changing device for processing machine

The present invention relates to a machining center, and in particular to a tool changing device for the machining center.

The machining center equipped with a tool magazine is known to achieve the purpose of quickly replacing machining tools through an automatic tool changing mechanism. The automatic tool changing mechanism includes a tool changing arm, which is composed of a tool arm connected to one end of a rotating shaft. When the rotating shaft is driven, the tool arm is driven to rotate to exchange tools. In addition, the entire tool changing arm of some models must be able to be controlled to move between two fixed points to adapt to different tool changing mechanisms, such as tool changing operations for vertical spindle heads or horizontal spindle heads.

A tool changing arm in a known tool changing mechanism is mounted on a rotating seat that can be turned over within a range of 90 degrees. By controlling the turning of the rotating seat, the entire tool changing arm can be driven to move between two fixed points at an angle of 0 and 90 degrees. However, the tool changing arm is heavy as a whole. In order to smoothly and steadily drive the rotating seat to turn over, a known method is to use a hydraulic cylinder that can generate a larger output power as a power source. However, using hydraulic means as a method of driving the rotating seat to turn over has the potential problem of inaccurate turning positioning of the rotating seat, and the hydraulic cylinder structure has the problem of hydraulic oil leakage and environmentally unfriendly subsequent treatment of the hydraulic oil. In addition, the use is also limited by the hydraulic oil temperature not being too high. Therefore, the existing tool changing mechanism capable of moving between two fixed points is not perfect and needs to be improved.

In view of this, the object of the present invention is to provide a tool changing device for a processing machine, which can ensure accurate flipping and positioning of the rotary seat.

In order to achieve the above-mentioned object, the present invention provides a tool changing device for a processing machine, which includes a fixed machine base, a transmission mechanism and a tool changing arm. The transmission mechanism is combined with the machine base and includes a displacement cam, a follower, a rotating shaft and a rotating seat; the displacement cam is controlled to rotate around a first axis, the surface of the displacement cam has a curved groove, the follower has a protrusion embedded in the curved groove, when the displacement cam rotates, the follower reciprocates along the first axis, the rotating shaft passes through the machine base and can rotate around a second axis, the part of the rotating shaft located on the inner side of the machine base is connected to the follower in an interlocking manner, and the part of the rotating shaft located on the outer side of the machine base is fixedly connected to the rotating seat; the tool changing arm is connected to the rotating seat and can swing between a first position and a second position.

The effect of the present invention is that the displacement cam is driven to drive the follower to translate, and the translated follower is then linked to the rotation shaft through an interlocking manner, and the rotating shaft can drive the tool changing arm to accurately pivot and position between two fixed points.

In order to explain the present invention more clearly, a preferred embodiment is given and described in detail with reference to the drawings. Referring to Figures 1 to 3, a tool changing device 100 for a processing machine of a preferred embodiment of the present invention is used to exchange a tool on the spindle of the processing machine with a tool in a tool magazine. The tool changing device 100 includes a fixed machine base 10, a tool changing arm 20 and a transmission mechanism 30, wherein the tool changing arm 20 includes a rotating shaft 21 and a knife arm 22, one end of the rotating shaft 21 is connected to the knife arm 22, and the knife arm 22 has two opposite ends and is used to clamp a knife rod (not shown), respectively, and the rotating shaft 21 can be driven to drive the knife arm 22 to perform 180-degree rotation switching.

The transmission mechanism 30 is combined with the machine base 10 to drive the tool changing arm 20 to move between two fixed points. In the present embodiment, the transmission mechanism 30 can drive the tool changing arm 20 to flip back and forth between two fixed points at an angle of 0 degree (see FIG. 3 ) and 90 degrees (see FIG. 9 ). It must be noted that the angles of the two fixed points are not limited to 0 degree and 90 degree, and can be adjusted according to actual needs. The following describes a specific structure capable of driving the tool changing arm 20 to move between two fixed points, wherein the machine base 10 has a base 11 and a vertical wall 12 connected to the base 11. The side of the vertical wall 12 facing the tool changing arm 20 is defined as the outer side, and the opposite side is defined as the inner side. The vertical wall 12 is provided with two convex walls 13 on one side of the inner side, and a front cover 14 is detachably connected to bridge the two convex walls 13.

Please refer to FIG. 4 and FIG. 5 , the transmission mechanism 30 includes a gear shaft 31, a rotating shaft 32, an intermediate gear 33, a driven gear 34 and a rotating seat 35. The two ends of the gear shaft 31 and the rotating shaft 32 are respectively passed through the vertical wall 12 and the front cover 14 and are rotatably arranged in parallel between the two convex walls 13; the intermediate gear 33 is sleeved on the gear shaft 31, and the driven gear 34 is sleeved on the rotating shaft 32. The driven gear 34 and the rotating shaft 32 are linked by providing a key slot and installing a key (not shown). The intermediate gear 33 engages with the driven gear 34. The gear 34 has a number of teeth less than that of the driven gear 34; the rotating seat 35 is arranged on the outer side of the vertical wall 12 of the machine base 10 and is fixedly connected to a chassis 23 of the tool changing arm 20 through a plurality of bolts 24, and the rotating seat 35 has a plurality of through holes 351 and is fixedly connected to the rotating shaft 32 through a plurality of bolts 36 that respectively pass through one of the through holes 351 and lock into one end of the rotating shaft 32 that passes through the vertical wall 12. When the rotating shaft 32 rotates, it can drive the rotating seat 35 and the tool changing arm 20 to rotate together. In addition, the rotating shaft 32 is optionally provided with a baffle 37 at the portion where it passes through the vertical wall 12. The baffle 37 is located between the vertical wall 12 and the rotating seat 35 to prevent dust or debris in the working environment from accidentally falling between the rotating shaft 32 and the vertical wall 12 and hindering the smooth rotation of the rotating shaft 32.

6 and 7 , the transmission mechanism 30 further includes a transmission base 38 , a displacement cam 39 , a motor 40 , a slide block 41 , a linear rail 42 and a follower 43 . The transmission base 38 is coupled to the vertical wall 12 of the machine base 10 through a plurality of positioning pins 44. The transmission base 38 has a right end plate 381 and a left end plate 382 separated by a distance, and a front bearing 45 and a rear bearing 46 are respectively provided on the right end plate 381 and the left end plate 382; the displacement cam 39 is a cylindrical cam in this embodiment, and its two ends are respectively inserted into the front bearing 45 and the rear bearing 46, and coupled to the transmission base 38 in a rotatable manner, and a curved groove 391 is provided on the surface of the displacement cam 39; the motor 40 is connected to the left end plate 382 of the transmission base 38, and can drive the displacement cam 39 to rotate around a first axis L1.

The slider 41, the linear rail 42 and the follower 43 are disposed between the intermediate gear 33 and the displacement cam 39, wherein the slider 41 is fixedly coupled to the vertical wall 12, the linear rail 42 cooperates with the slider 41 in a sliding pair manner, and the follower 43 is fixedly connected to the linear rail 42 as a whole through a plurality of screws 47. The top surface of the follower 43 has a tooth surface 431 arranged along the first axis L1, and the tooth surface 431 is engaged with the intermediate gear 33. The bottom surface of the follower 43 has a protrusion 432, and the protrusion 432 is embedded in the curved groove 391 of the displacement cam 39. In this embodiment, the protrusion 432 is a shaft bearing including a shaft 432a and a head 432b. One end of the shaft 432a is connected to the bottom surface of the follower 43, and the other end is connected to the head 432b. The head 432b is located in the curved groove 391. When the head 432b is designed to be rotatable, the contact wear with the curved groove 391 can be reduced. When the head 432b is designed to be non-rotatable, it forms an integrated structure with the shaft 432a to enhance its own stability.

The above is a structural description of the tool changing device 100 of the preferred embodiment of the present invention, and its operation method is then described below.

Please refer to FIG. 3 and FIG. 8 , which show that the tool change arm 20 is in an upright state. Here, the tool change arm 20 in this state is defined as being in a first position P1. Please refer to FIG. 9 and FIG. 10 , when the motor 40 is started to drive the displacement cam 39, the rotating displacement cam 39 guides the protrusion 432 through its curved groove 391, and the follower 43 is constrained by the sliding pair of the slider 41 and the linear rail 42, and can only translate along the first axis L1. At the same time, the tooth surface 431 of the follower 43 engages the linkage. The intermediate gear 33 is engaged with the driven gear 34, and the rotating driven gear 34 drives the rotating shaft 32 to rotate around a second axis L2 (see FIG. 4 ), so that the rotating seat 35 and the tool changing arm 20 can be driven to turn synchronously. When the tool changing arm 20 is pivoted to a horizontal position, the tool changing arm 20 in this state is defined to be at a second position P2. On the contrary, when the displacement cam 39 is controlled to reverse, the tool changing arm 20 can be pulled back to the first position P1. It is worth mentioning that the stroke length of the curved groove 391 of the displacement cam 39 is precisely designed so that the tool changing arm 20 can be pivoted between the first position P1 and the second position P2.

In addition, the present invention may further provide a limiting means for accurately positioning the tool changing arm 20 at the first position P1 or the second position P2. Referring to FIG. 4 and FIG. 5 , the limiting means of the present embodiment includes a block 15 disposed on the outer side of the vertical wall 12 of the machine base 10, the block 15 having a resisting surface 15a, and a first resisting portion 352 and a second resisting portion 353 disposed at two different points of the rotating seat 35, respectively. When the first abutting portion 352 contacts the upper portion of the abutting surface 15a, the tool changing arm 20 is precisely positioned at the first position P1 (see FIG. 3 and FIG. 8 ), and when the second abutting portion 353 contacts the lower portion of the abutting surface 15a, the tool changing arm 20 is precisely positioned at the second position P2 (see FIG. 9 and FIG. 10 ). In other words, based on the precise design of the curved groove 391 and the setting of the block 15, the excessive deflection of the rotating seat 35 can be prevented to ensure that the tool changing arm 20 is precisely positioned at the first position P1 or the second position P2. In a specific application example, the first abutting portion 352 and the second abutting portion 353 are a kind of bolt, and by fine-tuning the depth of the bolt locked into the rotating seat 35, the first abutting portion 352 or the second abutting portion 353 can be made to contact the abutting surface 15a earlier or later, so that the tool changing arm 20 can obtain a precise positioning effect. It is also mentioned that the aforementioned embodiment is to set the abutting surface 15a on the machine base 10, and to set the first abutting portion 352 and the second abutting portion 353 on the rotating seat 35. However, depending on actual needs, the first abutting portion and the second abutting portion can also be set on the machine base, and the abutting surface can be set on the rotating seat.

In the above-mentioned embodiment, electric control is used as the power source for driving the tool changing arm 20 to swing, that is, the displacement cam 39 is directly driven by the motor 40 to rotate forward and reversely, thereby driving the follower 43 to reciprocate along the first axis L1 direction, thereby achieving the purpose of controlling the tool changing arm 20 to swing between two fixed points. This improves the existing problem of hydraulic oil leakage and subsequent environmentally unfriendly treatment of hydraulic oil when the hydraulic cylinder is used to drive the tool changing arm to move between two fixed points, and the structure of the present invention is not restricted by the use of excessively high hydraulic oil temperature.

The above-mentioned follower 43 is engaged with the driven gear 34 sleeved on the rotating shaft 32 located on the inner side of the machine base 10 to achieve the purpose of driving the tool changing arm 20 to rotate. In the above-mentioned embodiment, an intermediate gear 33 is set between the driven gear 34 and the tooth surface 431 of the follower 43. However, it should be noted that the number of intermediate gears is not limited to one, and can be increased depending on actual needs. In addition, it is not ruled out that the circumferential surface of the above-mentioned rotating shaft can be set as a tooth surface and directly engaged with the tooth surface of the follower, thereby omitting the setting of the intermediate gear.

The tool changing device of the present invention can be further provided with an angle detection module to detect the rotation angle of the displacement cam so as to control the motor to stop running in time. Referring to FIG. 1 and FIG. 6 , the angle detection module 50 is mounted on the transmission base 38 of the tool changing device 100 of the above embodiment. As shown in FIG. 7 and FIG. 11 , the angle detection module 50 includes a magnet 51, an angle sensor 52 and a controller 53. The magnet 51 is located on an end surface of the displacement cam 39 through a fixing ring 54 inserted in a side hole 392 of the displacement cam 39 and can rotate with the rotation of the displacement cam 39. The angle sensor 52 is fixed on the right end plate 381 of the transmission base 38. The angle sensor 52 has a sensing surface 52a which is separated from a sensed surface 51a of the magnet 51 by a micro-distance, wherein the micro-distance is set between 1.5 mm and 3.5 mm, and preferably 2.5 mm. The sensing surface 52a senses the rotation angle change of the magnetic field lines of the magnet 51 in a non-contact manner. When the rotation angle of the sensed magnetic field lines (equivalent to the rotation angle of the displacement cam) meets the preset value, the controller 53 receives the signal generated by the angle sensor 52 and controls the motor 40 to stop running. The preset rotation angle value corresponds to the two fixed positions of the tool changing arm 20 at an angle of 0 degree and 90 degrees, that is, when the tool changing arm 20 reaches the first position P1 or the second position P2, the motor 40 stops running to avoid excessive swinging of the tool changing arm 20.

In addition, the angle detection module can also be composed of two angle detectors and two sensing blocks, as shown in FIG12 , the two angle detectors 55 are a kind of proximity switch and are respectively connected to a fixed plate 57, the fixed plate 57 is fixed to the right end plate 381 of the transmission seat 38; the two sensing blocks 56 are a kind of signal cam and are sleeved on one end of the displacement cam 39 in a manner that can rotate synchronously with the displacement cam 39, and the two sensing blocks 56 respectively have a protruding sensed portion 56a, and each sensed portion 56a is staggered. When each angle detector 55 detects a sensed portion 56a in time, a signal corresponding to the rotation angle is generated, and the signal is also used to control the motor 40 to stop running.

In addition, the tool changing device of the present invention can be equipped with two more position detectors to detect the position of the driven member. In FIG12 , the two position detectors 58 and the two angle detectors 55 are electrically connected to a controller (not shown), and the two position detectors 58 are spaced apart and connected to a fixing plate 59, which is fixed to a front end plate 383 of the transmission seat 38, and one of the screws used to lock the driven member 43 and the rail 42 together is replaced by a screw 48 having a head, and the head constitutes a sensed portion 48a. When the displacement cam 39 rotates and one of the angle detectors 55 sends a signal corresponding to the rotation angle, one of the two position detectors 58 will detect the sensed portion 48a on the translated follower 43 and generate a confirmation signal, so that it can be confirmed that the follower 43 has moved to the correct position. On the contrary, if the angle detector 55 sends a signal corresponding to the rotation angle, but the position detector 58 does not send a corresponding confirmation signal, it means that the follower 43 has not moved to the correct position as expected. At this time, the controller will generate a warning signal as a fault reminder so that the obstacle can be eliminated in time. The above-mentioned position detector can also be used in conjunction with an angle detection module composed of a magnet and an angle sensor.

As can be seen from the above, the tool changing device 100 of the present invention can not only pivot within a preset range, but also be accurately positioned at the first position P1 or the second position P2 through the linkage relationship between the displacement cam 39, the driven member 43, the intermediate gear 33 and the driven gear 34. In addition, in order to effectively eliminate the backlash, the present invention further provides a fine adjustment means that can drive the transmission base 38 to move along the direction of the first axis L1. The fine adjustment means includes at least one adjustment rod, and the transmission base 38 and the machine base 10 are matched in a sliding manner. Based on the displacement cam 39 being combined with the transmission base 38, when the at least one adjustment rod is driven, the transmission base 38 and the displacement cam 39 can be linked to move synchronously.

Please refer to Figures 13 to 15. In one embodiment for achieving the above purpose, the machine base 10 is provided with two parallel restraining surfaces 16 on the inner surface of the vertical wall 12, and the transmission base 38 is formed with a shoulder 385 along the upper and lower edges of a rear end plate 384. The vertical wall 12 is provided with a plurality of positioning holes 12a, and the rear end plate 384 has a plurality of long slot holes 384a. When installing the transmission base 38, the shoulder 385 is matched with the restraining surface 16, and the positioning pins 44 are respectively passed through one of the long slot holes 384a and extended into the corresponding positioning holes 12a, so that the transmission base 38 can be displaced along the direction of the first axis L1 within the long axial range of the long slot hole 384a. In one embodiment, the aforementioned positioning hole 12a is a screw hole, and the aforementioned positioning pin 44 is a bolt.

In addition, the at least one adjusting rod includes a first adjusting rod 60 and a second adjusting rod 61, for example, a bolt. In the present embodiment, the first adjusting rod 60 and the second adjusting rod 61 are arranged on the same side, wherein the first adjusting rod 60 is locked into a fixing block 62 fixedly connected to the vertical wall 12, and the fixing block 62 constitutes a fixed support point when the first adjusting rod 60 rotates. Therefore, when the first adjusting rod 60 is driven forward, the first adjusting rod 60 will push the transmission seat 38 to move in a first direction D1. The second adjusting rod 61 is directly locked into a screw hole 386 of the transmission seat 38, and one end of the second adjusting rod 61 abuts against the body of the positioning pin 44. Since one end of the positioning pin 44 extends into the positioning hole 12a, when the second adjusting rod 61 is driven, the positioning pin 44 in contact with the second adjusting rod 61 constitutes a fixed support point. When the second adjusting rod 61 continues to be locked into the screw hole 386, the transmission seat 38 is pulled and displaced in a second direction D2 opposite to the first direction D1. At this point, the displacement cam 39 is moved synchronously.

In the above, the displacement cam 39 that moves synchronously with the transmission seat 38 will push the follower 43 to move through the protrusion 432, which is beneficial to eliminate the backlash and can also achieve the purpose of fine-tuning the swing direction of the entire tool change arm 20. It should be noted that in other embodiments, the first adjustment rod 60 and the second adjustment rod 61 can also be arranged on the opposite side, that is, respectively located on the outer side of the right end plate 381 and the left end plate 382; in addition, a U-shaped nut 63 can be locked on the first adjustment rod 60 and the second adjustment rod 61 respectively to ensure the positioning of the first adjustment rod 60 and the second adjustment rod 61.

The above description is only the preferred embodiment of the present invention. Any equivalent changes made by applying the present invention specification and the scope of patent application should be included in the patent scope of the present invention.

[The present invention] 100: tool changer 10: machine base 11: base 12: vertical wall 12a: positioning hole 13: convex wall 14: front cover 15: block 15a: abutment surface 16: restraint surface 20: tool changer arm 21: rotating shaft 22: tool arm 23: chassis 24: bolt 30: transmission mechanism 31: gear shaft 32: rotating shaft 33: intermediate gear 34: driven gear 35: rotating seat 351: through hole 352: first abutment portion 353: second abutment portion 36: bolt 37: baffle 38: transmission seat 381: right end plate 382: left end plate 383: front end plate 384: rear end plate 384a: slotted hole 385: shoulder 386: screw hole 39: displacement cam 391: curved groove 392: side hole 40: motor 41: slider 42: linear rail 43: follower 431: tooth surface 432: protrusion 432a: rod body 432b: head 44: positioning pin 45: front bearing 46: rear bearing 47: screw 48: screw 48a: sensed part 50: angle detection module 51: magnet 51a: sensed surface 52: Angle sensor 52a: Sensing surface 53: Controller 54: Fixing ring 55: Angle detector 56: Sensing block 56a: Sensing part 57: Fixing plate 58: Position detector 59: Fixing plate 60: First adjustment rod 61: Second adjustment rod 62: Fixing block 63: U-shaped nut L1: First axis L2: Second axis P1: First position P2: Second position

FIG1 is a three-dimensional diagram of a tool changing device for a processing machine of a preferred embodiment of the present invention; FIG2 is an exploded view of the tool changing device for the processing machine shown in FIG1; FIG3 is a front view of the tool changing device for the processing machine shown in FIG1, revealing that the tool changing arm is located in the first position; FIG4 is an exploded view of some components of the tool changing device for the processing machine shown in FIG2; FIG5 is a three-dimensional view of the combination of the components shown in FIG4 and another viewing angle; FIG6 is an exploded view of some components of the transmission mechanism in the tool changing device for the processing machine shown in FIG2; FIG7 is an exploded view of the components shown in FIG6; FIG8 is a simplified diagram of the transmission mechanism in the tool changing device for the processing machine shown in FIG3, revealing that the first abutting portion of a rotating seat contacts a block; FIG9 is similar to FIG3, revealing that the tool changing arm is located in the second position; FIG10 is similar to FIG8, revealing that the second abutment portion of the rotating seat contacts the block; FIG11 is a partial enlarged and cross-sectional view of the structure shown in FIG8, revealing the positional relationship between an angle detection module and a displacement cam; FIG12 is a three-dimensional view, revealing the positional relationship between another angle detection module and a transmission mechanism; FIG13 is a partial component exploded view of the tool changing device of the processing machine shown in FIG1; FIG14 is a cross-sectional view, revealing the assembly relationship between the transmission seat and the vertical wall; and FIG15 is a partial enlarged view of the transmission mechanism in the tool changing device of the processing machine shown in FIG3.

100: Tool changing device

10: Base

11: Base

12: Wall erection

13: Convex wall

14: Front cover

20: Tool change arm

21: Rotation axis

22: Blade Arm

23: Chassis

30: Transmission mechanism

34: Driven gear

35: Rotating seat

38: Transmission seat

39: Displacement cam

40: Motor

44: Positioning pin

50: Angle detection module

Claims (13)

A tool changing device for a processing machine comprises: a fixed machine base; a transmission mechanism, which is combined with the machine base and includes a displacement cam, a driven member, a rotating shaft and a rotating seat; wherein the displacement cam is controlled to rotate around a first axis, the surface of the displacement cam has a curved groove, the driven member has a protrusion embedded in the curved groove, when the displacement cam rotates, the driven member reciprocates along the first axis, the rotating shaft passes through the machine base and can rotate around a second axis, the part of the rotating shaft located on the inner side of the machine base is connected to the driven member in an interlocking manner, and the part of the rotating shaft located on the outer side of the machine base is fixedly connected to the rotating seat; and A tool changing arm is connected to the rotating seat and can pivot between a first position and a second position. A tool changing device for a processing machine as described in claim 1, wherein the transmission mechanism includes a driven gear, the driven gear is sleeved on the rotating shaft, the driven member has a tooth surface arranged along the first axial direction, the driven member is linked to the driven gear in an interlocking manner through its tooth surface, and the driven gear links the rotating shaft to rotate. A tool changing device for a processing machine as described in claim 2, wherein the transmission mechanism includes at least one intermediate gear, the tooth surface of the driven member engages with the intermediate gear, the at least one intermediate gear engages with the driven gear, and the number of teeth of the at least one intermediate gear is less than the number of teeth of the driven gear. A tool changing device for a processing machine as described in claim 1, wherein the transmission mechanism includes a linear rail and a slider, one of the linear rail and the slider is fixedly connected to the machine base, and the other is fixedly connected to the follower, and the linear rail and the slider cooperate in a sliding pair manner. A tool changing device for a processing machine as described in claim 1, wherein the transmission mechanism includes a transmission base, the transmission base is combined with the machine base, and the displacement cam is rotatably arranged on the transmission base; the tool changing device includes a fine-tuning means, which is used to drive the transmission base to displace along the direction of the first axis. A tool changing device for a processing machine as described in claim 5, wherein the fine-tuning means includes at least one adjusting rod, and the transmission seat and the machine base cooperate in a sliding manner, and the at least one adjusting rod is driven to rotate to link the transmission seat to move. A tool changing device for a processing machine as described in claim 6, wherein the transmission base has a plurality of long slot holes, the machine base has a plurality of positioning holes, and a plurality of positioning pins respectively pass through one of the long slot holes and extend into the corresponding positioning holes; the at least one adjusting rod includes a first adjusting rod and a second adjusting rod, wherein the first adjusting rod is driven to rotate and links the transmission base to move in a first direction, and the second adjusting rod is driven to rotate and links the transmission base to move in a second direction, and the first direction and the second direction are opposite directions. A tool changing device for a processing machine as described in claim 1, wherein the transmission mechanism includes a transmission base and a motor, the transmission base is combined with the machine base, the displacement cam is arranged on the transmission base, and the motor is combined with the transmission base and used to drive the displacement cam to rotate; the tool changing device includes an angle detection module, which is combined with the transmission base and used to detect the rotation angle of the displacement cam. A tool changing device for a processing machine as described in claim 8, wherein the angle detection module includes a magnet and an angle sensor, the magnet is arranged on one end face of the displacement cam and rotates with the rotation of the displacement cam, the angle sensor is fixed to the transmission seat, and senses the rotation angle of the magnetic field lines of the magnet in a non-contact manner and generates a signal, and the signal controls the motor to stop running. A tool changing device for a processing machine as described in claim 8, wherein the angle detection module includes two angle detectors arranged on the transmission base, and two sensed parts arranged on the displacement cam and capable of rotating synchronously with the displacement cam, each of the angle detectors detects one of the sensed parts and generates a signal, and the signal controls the motor to stop running. The tool changing device of the processing machine as described in claim 9 or 10 includes two position detectors arranged on the transmission base, and a sensed part arranged on the driven member, each of the position detectors is electrically connected to the angle detection module, and when the angle detection module sends the signal, it detects the sensed part on the driven member and generates a confirmation signal. The tool changing device of the processing machine as described in claim 1 includes a limiting means for positioning the tool changing arm at the first position or the second position. A tool changing device for a processing machine as described in claim 12, wherein the limiting means includes a stop surface provided on the machine base, and a first stop portion and a second stop portion provided on the rotating seat, wherein when the first stop portion contacts the stop surface, the tool changing arm is located at the first position, and when the second stop portion contacts the stop surface, the tool changing arm is located at the second position.

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