A tool changer for a CNC machining center

Abstract

This invention relates to the field of tool changing devices, specifically to a tool changing device for a CNC machining center, comprising a tool changing platform, a rotating shaft, and two tool arms. The rotating shaft is rotatable around its own axis. Both tool arms are mounted on the rotating shaft and rotate synchronously with it. Each tool arm has a cavity containing a counterweight, a connecting block, and a spring block. A clamping block is mounted on the tool arm, defining a clamping space for holding the tool between the clamping block, the spring block, and the tool arm. During tool changing, this CNC machining center tool changing device adjusts the centrifugal force on the counterweight according to the different rotational states of the rotating shaft during tool clamping and release, thereby changing the clamping force on the tool. This avoids situations where the tool cannot be released quickly due to excessive clamping force, or where the tool falls due to insufficient clamping force, ensuring normal machining operations.

Description

Technical Field

[0001] This invention relates to the field of tool changing device technology, and more specifically to a tool changing device for CNC machining centers. Background Technology

[0002] A CNC machining center is a highly efficient automated machine tool composed of mechanical equipment and a CNC system. It typically includes a bed, column, spindle box, worktable, tool magazine, tool changer, and control system. The tool changer, as a key component, is responsible for quickly and accurately changing tools during machining to meet the needs of different processes.

[0003] In existing technologies, the tool changing process in CNC machining centers is characterized by high speed and continuous operation. While this high-speed tool changing mode greatly improves the continuity of machining, it also brings a series of problems. In particular, the clamping force of the tool arm's jaws is constant when holding the tool. However, in actual operation, if the clamping force is too large, the tool may not be able to release quickly during high-speed tool changing. When the machining center needs to change tools, this overly tight clamping will hinder the tool from smoothly disengaging from the jaws, thus affecting the speed of the entire tool changing process. This may not only prolong the machining center's downtime and reduce machining efficiency but also potentially delay production schedules. Conversely, if the clamping force is too small, the tool is prone to falling off during the tool changing process due to the high speed, inertia, and vibration. A tool falling off at an inappropriate time may damage other components inside the machining center, such as scratching the worktable or damaging the workpiece being machined. Furthermore, tool falling can damage the tool itself, increasing tool wear costs and requiring additional time to handle these unexpected situations, severely disrupting the normal operation of the machining process. Summary of the Invention

[0004] This invention provides a tool changing device for CNC machining centers to solve the problem that the clamping force of the tool jaws in existing tool arms is constant. If the clamping force is too large, the tool cannot be released quickly; if the clamping force is too small, the tool will fall off.

[0005] The present invention provides a tool changing device for a CNC machining center, which adopts the following technical solution: A tool changing device for a CNC machining center, used for changing tools on a tool magazine, includes a tool changing platform, a rotating shaft, and two tool arms; the rotating shaft is arranged on the tool changing platform along a first direction and can rotate around its own axis, the first direction being vertical; both tool arms are arranged along a second direction, both tool arms are mounted on the rotating shaft and can rotate synchronously with the rotating shaft, the second direction being horizontal; a cavity is provided on the tool arm, and a counterweight, a connecting block, and a spring block are arranged sequentially along the second direction in the cavity, and the counterweight is located on the side of the connecting block in the second direction close to the vertical central axis of the rotating shaft; both the counterweight and the connecting block can move in the cavity along the second direction; the counterweight and the connecting block are connected by a first elastic element, the first elastic element being arranged along the second direction; one end of the spring block along the second direction is connected to the connecting block, and the other end of the spring block along the second direction extends out of the tool arm; a clamping block is installed on the tool arm, and the clamping block, the spring block, and the tool arm define a clamping space for clamping the tool.

[0006] Furthermore, a slide is provided on the connecting block, and the spring block is slidably installed in the slide through the first piston. The spring block and the first piston are integrally formed, and the first piston and the slide are slidably sealed. A hydraulic chamber is defined between the first piston and the slide, and the hydraulic chamber is filled with hydraulic oil. The clamping block and the hydraulic chamber are connected by a connecting pipe, and the connecting pipe is filled with hydraulic oil.

[0007] Furthermore, a connecting channel is provided on the cutter arm, and a connecting pipe is set in the connecting channel. One end of the connecting pipe is connected to the hydraulic chamber; the clamping block is installed on the other end of the connecting pipe through a second piston, and the second piston slides and seals with the connecting pipe.

[0008] Furthermore, an air passage is provided on the connecting block, and the slide and the air passage are arranged sequentially and interconnected in the second direction. The air passage is located on the side of the slide near the first elastic member in the second direction, and in the second direction, the air passage passes through the end of the connecting block near the first elastic member.

[0009] Furthermore, a second elastic element is provided between the second piston and the connecting pipe, and the second elastic element is arranged along the second direction.

[0010] Furthermore, a limit block is fixedly installed inside the cavity, and the counterweight block abuts against the limit block in the initial state.

[0011] Furthermore, a mounting plate is provided on the tool changing platform. The mounting plate is fixedly connected to the rotating shaft. Both tool arms are rotatably mounted on the mounting plate around a third direction, which is horizontal and perpendicular to the second direction. An active space is defined between the lower surface of the tool arm and the mounting plate. A third elastic element is provided in the active space. The third elastic element is arranged along the first direction, and its two ends along the first direction are fixedly connected to the tool arm and the mounting plate, respectively.

[0012] Furthermore, each cutter arm is rotatably connected to the mounting plate via a pin, which is set along a third direction.

[0013] Furthermore, an outer edge plate is provided on the rotating shaft, which is arranged around the first direction on the rotating shaft and simultaneously abuts against the upper surfaces of the two cutter arms.

[0014] Furthermore, an installation channel is provided on the cutter arm, which is arranged along the second direction and communicates with the cavity. The spring block passes through the installation channel and extends out of the cutter arm.

[0015] The beneficial effects of this invention are as follows: A tool changing device for a CNC machining center, by creating a cavity in the tool arm and placing a counterweight and a connecting block within the cavity, allows the counterweight to be subjected to outward centrifugal force during tool changing due to the centrifugal force of rotation. This outward movement of the counterweight compresses the first elastic element, which in turn applies an additional force to the connecting block, thereby increasing the force of the spring block connected to the connecting block. When the tool is clamped within the clamping space defined by the clamping block, the spring block, and the tool arm, this force acts directly on the tool. As the rotating shaft rotates around its own axis, the force on the tool increases, making the tool clamped more secure and preventing tool drop during rotational tool changing. When the tool needs to be separated from the tool arm, the rotating shaft stops rotating. At this time, the counterweight is no longer subjected to centrifugal force, and the counterweight and the first elastic element return to their original positions. This relatively reduces the force on the connecting block and the spring block, preventing the tool from being unloaded smoothly due to excessive clamping force. During tool changing, the centrifugal force on the counterweight varies depending on the rotation state of the rotating shaft when clamping and releasing the tool. This changes the clamping force on the tool, minimizing the possibility of the tool failing to release quickly due to excessive clamping force or falling due to insufficient clamping force, thus ensuring normal machining operations. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of a tool changing device for a CNC machining center according to the present invention;

[0018] Figure 2 This is a top view of the overall structure of an embodiment of a tool changing device for a CNC machining center according to the present invention;

[0019] Figure 3This is a schematic diagram of a tool arm according to an embodiment of a tool changing device for a CNC machining center of the present invention;

[0020] Figure 4 This is a front view of the tool arm of an embodiment of a tool changing device for a CNC machining center according to the present invention;

[0021] Figure 5 for Figure 4 Sectional view at point AA along the middle;

[0022] Figure 6 for Figure 5 Enlarged view of point B in the middle;

[0023] Figure 7 for Figure 5 Enlarged view of point C in the middle;

[0024] Figure 8 This is a partial sectional view of the overall structure of an embodiment of a tool changing device for a CNC machining center according to the present invention;

[0025] Figure 9 for Figure 8 Enlarged view of point D in the middle.

[0026] In the diagram: 100, tool magazine; 200, tool changing platform; 300, rotating shaft; 310, outer edge plate; 400, tool arm; 410, cavity; 420, counterweight; 430, connecting block; 431, slide rail; 432, air passage; 440, spring block; 441, locking block; 442, first piston; 443, hydraulic chamber; 450, first elastic element; 460, clamping block; 461, second piston; 462, second elastic element; 470, connecting pipe; 480, limiting block; 500, mounting plate; 510, moving space; 520, third elastic element; 530, pin. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] An embodiment of the tool changing device for a CNC machining center according to the present invention, such as... Figures 1 to 9 As shown.

[0029] A tool changing device for a CNC machining center, used for changing tools on a tool magazine 100, includes a tool changing platform 200, a rotary axis 300, and two tool arms 400. The rotary axis 300 is arranged on the tool changing platform 200 along a first direction and is capable of rotating about its own axis; the first direction is vertical. Both tool arms 400 are arranged along a second direction, both mounted on the rotary axis 300, and are capable of rotating synchronously with the rotary axis 300; the second direction is horizontal. The two tool arms 400 are symmetrically arranged about the central axis of the rotary axis 300 in the first direction and are on the same horizontal plane.

[0030] The cutter arm 400 has a cavity 410. Within the cavity 410, a counterweight 420, a connecting block 430, and a spring block 440 are sequentially arranged along a second direction. The counterweight 420 is located on the side of the connecting block 430 along the second direction, closer to the vertical central axis of the rotation shaft 300. Both the counterweight 420 and the connecting block 430 are movable within the cavity 410 along the second direction. The counterweight 420 and the connecting block 430 are connected by a first elastic element 450, which is a spring and is arranged along the second direction. One end of the spring block 440 along the second direction is connected to the connecting block 430, and the other end of the spring block 440 extends out of the cutter arm 400. A clamping block 460 is mounted on the cutter arm 400. The clamping block 460, the spring block 440, and the cutter arm 400 define a clamping space for clamping the cutting tool.

[0031] Specifically, a motor is installed on the tool changing platform 200, and the rotating shaft 300 is mounted on the output shaft of the motor, so that the rotating shaft 300 can rotate around its own axis.

[0032] In this embodiment, a cavity 410 is formed on the cutter arm 400, and a counterweight 420 and a connecting block 430 are arranged within the cavity 410. When a cutter needs to be changed, the rotating shaft 300 is driven to rotate around its own axis. The rotation of the rotating shaft 300 will drive the two cutter arms 400 to rotate. Due to the centrifugal force of rotation, the counterweight 420 will be subjected to an outward centrifugal force, moving outward and compressing the first elastic element 450. The side closer to the vertical central axis of the rotating shaft 300 along the second direction is called the inner side, and the side farther away from the vertical central axis of the rotating shaft 300 is called the outer side. The deformation of the first elastic element 450 will increase the force on the connecting block 430, and the outward movement of the counterweight 420 only compresses the first elastic element 450, while the connecting block 430 remains relatively stationary. That is, the outward movement of the counterweight 420 compresses the first elastic element 450 and applies an additional force to the connecting block 430 through the first elastic element 450, thereby increasing the force of the elastic block 440 connected to the connecting block 430. When the tool is clamped within the clamping space defined by the clamping block 460, the spring block 440, and the tool arm 400, the force acts directly on the tool. As the rotating shaft 300 rotates around its own axis, the force on the tool increases, making the tool clamped more secure and preventing tool drop during rotational tool changing. When it is necessary to separate the tool from the tool arm 400, the rotating shaft 300 stops rotating. At this time, the counterweight 420 is no longer subjected to centrifugal force, and the counterweight 420 and the first elastic element 450 will return to their original positions. This reduces the force on the connecting block 430 and the spring block 440, preventing the tool from being unable to be released smoothly due to excessive clamping force. In other words, during tool changing, the centrifugal force on the counterweight 420 varies depending on the rotation state of the rotating shaft 300 during clamping and releasing, thus changing the clamping force on the tool. This minimizes the possibility of the tool being unable to be released quickly due to excessive clamping force, or falling due to insufficient clamping force, ensuring normal machining operations. It should be noted that the clamping block 460 is made of lightweight material, and the centrifugal force it experiences is negligible.

[0033] In this embodiment, the blade arm 400 is provided with an installation channel, which is arranged along the second direction and communicates with the cavity 410. The spring block 440 passes through the installation channel and extends out of the blade arm 400.

[0034] Furthermore, a locking block 441 is provided on the spring block 440 around the second direction. The locking block 441 is located inside the cavity 410. A boss is provided on the mounting channel around the second direction. The boss is located on the side of the locking block 441 away from the connecting block 430 in the second direction. When the tool is clamped in the clamping space, the locking block 441 does not abut against the boss.

[0035] By setting a locking block 441 to restrict the spring block 440 from exiting the cavity 410, and by ensuring that the locking block 441 does not abut against the boss when the tool is clamped in the clamping space, the force on the spring block 440 can be directly transmitted to the tool.

[0036] In another possible embodiment, the connecting block 430 has a slide rail 431, and the spring block 440 is slidably mounted in the slide rail 431 via the first piston 442. The spring block 440 and the first piston 442 are integrally formed, and the first piston 442 and the slide rail 431 are slidably sealed. A hydraulic chamber 443 is defined between the first piston 442 and the slide rail 431. The hydraulic chamber 443 is filled with hydraulic oil, and the clamping block 460 is connected to the hydraulic chamber 443 via a connecting pipe 470, which is also filled with hydraulic oil.

[0037] Specifically, a connecting channel is provided on the cutter arm 400, and a connecting pipe 470 is disposed within the connecting channel, with one end of the connecting pipe 470 communicating with the hydraulic chamber 443. A clamping block 460 is mounted on the other end of the connecting pipe 470 via a second piston 461, and the second piston 461 and the connecting pipe 470 are in a sliding seal. The clamping block 460 and the second piston 461 are integrally formed.

[0038] Specifically, the connecting block 430 is provided with an air passage 432. The slide 431 and the air passage 432 are arranged sequentially and connected to each other in the second direction. The air passage 432 is located on the side of the slide 431 in the second direction that is close to the first elastic member 450. In the second direction, the air passage 432 passes through the end of the connecting block 430 that is close to the first elastic member 450, so that the first piston 442 can slide in the slide 431.

[0039] Furthermore, a second elastic element 462 is provided between the second piston 461 and the connecting pipe 470. The second elastic element 462 is arranged along a second direction and is a spring. By providing the second elastic element 462, the clamping block 460 can be reset.

[0040] In this embodiment, by setting a first piston 442 and a second piston 461, before clamping the tool, the rotating shaft 300 rotates around its own axis, causing the counterweight 420 to move outward under the action of centrifugal force, and compressing the first elastic element 450, increasing the elastic force on the connecting block 430. At this time, the hydraulic oil in the hydraulic chamber 443 and the hydraulic oil in the connecting pipe 470 are kept in balance. The connecting block 430 and the spring block 440 can be regarded as a whole. Therefore, the elastic force of the first elastic element 450 is directly applied to the spring block 440 through the connecting block 430, and further applied to the tool. After the tool is clamped in the clamping space, the force on the tool is increased, making the tool clamped more firmly.

[0041] Furthermore, after the tool is clamped into the clamping space, the clamping block 460 will be compressed, compressing the second elastic element 462. This causes the hydraulic oil in the connecting pipe 470 to flow into the hydraulic chamber 443, giving the spring block 440 a tendency to move inward and the connecting block 430 a tendency to move outward. Since both the connecting block 430 and the spring block 440 have an outward tendency under the centrifugal force generated by the rotation of the rotating shaft 300, the connecting block 430 will move more outward than the spring block 440. It is easy to move outward, so the connecting block 430 will move outward and drive the counterweight block 420 to move outward through the first elastic element 450. As a result, when the rotating shaft 300 drives the tool arm 400 to rotate, the centrifugal force on the counterweight block 420 will be further increased, the deformation of the first elastic element 450 will be further increased, and the force on the spring block 440 will be further increased through the connecting block 430, thereby improving the clamping force of the spring block 440 on the tool and preventing the tool from falling off when clamping the tool.

[0042] Alternatively, in another possible embodiment, the connecting block 430 is fixedly connected to the spring block 440, and the clamping block 460 is fixedly connected to the blade arm 400, so that the force of the first elastic element 450 on the connecting block 430 can be directly applied to the spring block 440.

[0043] In another possible embodiment, a limiting block 480 is fixedly disposed within the cavity 410, and in the initial state, the counterweight 420 abuts against the limiting block 480. The limiting block 480 restricts the counterweight 420 from moving inward.

[0044] In another possible embodiment, the tool changing platform 200 is provided with a mounting plate 500, which is fixedly connected to the rotating shaft 300. Both tool arms 400 are rotatably mounted on the mounting plate 500 about a third direction, which is horizontal and perpendicular to the second direction. A movable space 510 is defined between the lower surface of the tool arm 400 and the mounting plate 500. A third elastic element 520, which is a spring, is provided within the movable space 510 and is arranged along a first direction. The two ends of the third elastic element 520 along the first direction are fixedly connected to the tool arm 400 and the mounting plate 500, respectively.

[0045] Specifically, each cutter arm 400 is rotatably connected to the mounting plate 500 via a pin 530. The pin 530 is set along a third direction, which is the axial direction of the pin 530. The cutter arm 400 can rotate around the axis of the pin 530.

[0046] Furthermore, an outer edge plate 310 is provided on the rotating shaft 300. The outer edge plate 310 is arranged on the rotating shaft 300 around the first direction and simultaneously abuts against the upper surfaces of the two cutter arms 400.

[0047] In this embodiment, by setting up a mounting plate 500, when the rotating shaft 300 rotates, the mounting plate 500 drives the two tool arms 400 to rotate. During tool changing, when the tool disengages from the tool arm 400, the tool arm 400 is allowed to swing downward within the movable space 510, compressing the third elastic element 520 and providing the tool arm 400 with a downward swing margin. This setting is because in the prior art, when the tool on the spindle of a CNC machining center is released, the tool arm 400 will swing downward due to the presence of the tool tip. Therefore, allowing the tool arm 400 to swing downward within the movable space 510 can prevent the tool arm 400 from bending and deforming under the influence of the tip. Furthermore, the tool arm 400 can automatically reset under the action of the third elastic element 520. The outer edge plate 310 can limit the upward swing of the tool arm 400, thus limiting the tool arm 400.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tool changing device for a CNC machining center, used for changing tools in a tool magazine, characterized in that: The device includes a tool changing platform, a rotating shaft, and two tool arms. The rotating shaft is positioned on the tool changing platform along a first direction and can rotate around its own axis; the first direction is vertical. Both tool arms are positioned along a second direction, mounted on the rotating shaft, and can rotate synchronously with the rotating shaft; the second direction is horizontal. A cavity is formed on each tool arm, within which a counterweight, a connecting block, and a spring block are sequentially arranged along the second direction. The counterweight is located on the side of the connecting block along the second direction, closer to the vertical center axis of the rotating shaft. Both the counterweight and the connecting block can move within the cavity along the second direction. The counterweight and the connecting block are connected by a first elastic element, which is positioned along the second direction. One end of the spring block along the second direction is connected to the connecting block, and the other end of the spring block extends out of the tool arm. A clamping block is mounted on the tool arm. The clamping block, the spring block, and the tool arm are connected... The clamping block is designed to define a clamping space for holding the cutting tool. A slide rail is provided on the connecting block, and a spring block is slidably installed within the slide rail via a first piston. The spring block and the first piston are integrally formed, and the first piston and the slide rail are slidably sealed. A hydraulic chamber is defined between the first piston and the slide rail, and the hydraulic chamber is filled with hydraulic oil. The clamping block and the hydraulic chamber are connected by a connecting pipe, which is also filled with hydraulic oil. A connecting channel is provided on the cutting arm, and a connecting pipe is located within the connecting channel. One end of the connecting pipe communicates with the hydraulic chamber. The clamping block is installed at the other end of the connecting pipe via a second piston, and the second piston and the connecting pipe are slidably sealed. An air passage is provided on the connecting block. The slide rail and the air passage are sequentially arranged and interconnected in the second direction. The air passage is located on the side of the slide rail closer to the first elastic element in the second direction, and in the second direction, the air passage passes through the end of the connecting block closest to the first elastic element.

2. The tool changer for a CNC machining center according to claim 1, characterized in that: A second elastic element is provided between the second piston and the connecting pipe, and the second elastic element is arranged along the second direction.

3. The tool changing device for a CNC machining center according to claim 1, characterized in that: A limit block is fixedly installed inside the cavity, and the counterweight block abuts against the limit block in the initial state.

4. The tool changing device for a CNC machining center according to claim 1, characterized in that: The tool changing platform is equipped with a mounting plate, which is fixedly connected to the rotating shaft. Both tool arms are rotatably mounted on the mounting plate around a third direction, which is horizontal and perpendicular to the second direction. The lower surface of the tool arm and the mounting plate define an active space. A third elastic element is provided in the active space. The third elastic element is arranged along the first direction, and its two ends along the first direction are fixedly connected to the tool arm and the mounting plate, respectively.

5. A tool changer for a CNC machining center according to claim 4, characterized in that: Each cutter arm is rotatably connected to the mounting plate via a pin, which is set along a third direction.

6. A tool changer for a CNC machining center according to claim 5, characterized in that: An outer edge plate is provided on the rotating shaft. The outer edge plate is arranged on the rotating shaft around a first direction and simultaneously abuts against the upper surfaces of the two cutter arms.

7. A tool changer for a CNC machining center according to claim 1, characterized in that: An installation channel is provided on the cutter arm. The installation channel is set along the second direction and communicates with the cavity. The spring block passes through the installation channel and extends out of the cutter arm.

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