Device for replacing cutter

Abstract

The invention provides a device for replacing tools, and relates to the technical field of machining equipment, the device comprises a tool magazine, the tool magazine is of a circular disc-shaped structure, a motor is fixedly mounted in the center of the tool magazine, a mounting plate is arranged above the motor, and a spindle box is arranged at the outer edge of the tool magazine; the motor for driving the tool magazine to rotate is directly and integrally installed in the center of the tool magazine, the traditional scheme that a side motor and a transmission mechanism (such as a gear and a synchronous belt) are arranged is abandoned, and the radial size of the device is greatly reduced; meanwhile, the tool holder mechanism is ingeniously arranged at the bottom of the spindle box, the whole device forms a concentric stacked structure of motor-tool magazine-spindle box, the layout is abnormally compact, precious space is vacated for arrangement of other parts of a machine tool, and the device is particularly suitable for a five-axis machining center or a small precision machine tool with strict requirements for the space.

Description

Technical Field

[0001] This invention relates to the field of machining equipment technology, and in particular to a device for changing cutting tools. Background Technology

[0002] In automated CNC machining centers, to complete multiple machining operations on a workpiece, such as milling, drilling, boring, and tapping, different tools need to be automatically changed according to program instructions during the machining process. The automatic tool changing device is an indispensable core functional component of modern machining centers, and its performance directly affects the machine tool's machining efficiency, accuracy, and reliability.

[0003] Currently, the mainstream tool changers in the industry are mainly divided into two types: one is the robotic arm tool changer, which uses an independent robotic arm to grab and exchange tools between the tool magazine and the spindle; the other is the robotic armless tool changer, which usually uses the movement of the tool magazine or the spindle box to allow the spindle to directly exchange tools with the tools on the tool magazine.

[0004] However, existing tool changing devices generally have the following significant drawbacks:

[0005] 1) Complex structure and large space occupation: Especially for robotic tool changers, complex linkage mechanisms, cam mechanisms, or hydraulic / pneumatic systems are required to drive the robotic arm to complete a series of compound actions such as tool grabbing, tool removal, rotation, and tool insertion. This not only increases the overall size and manufacturing cost of the machine tool, but also imposes strict requirements on the relative position of the tool magazine and the spindle, limiting the miniaturization and compact design of the machine tool.

[0006] 2) Tool changing accuracy is affected by mechanical wear: Traditional devices contain a large number of moving parts and transmission links, such as gears, cams, and slides. As the usage time increases, the wear of these parts will gradually accumulate, leading to a decrease in tool changing positioning accuracy, resulting in problems such as poor centering and unstable tool clamping. In severe cases, it may cause the tool to be scratched against the spindle taper hole, or even cause tool drop accidents, affecting machining quality and equipment safety.

[0007] 3) Insufficient alignment accuracy between the tool magazine and the spindle box: In existing devices, the positioning of the tool magazine and the tool gripping action of the spindle are often controlled by two independent systems. Their synchronization and alignment accuracy depend on a complex electrical control system and high-precision sensors. Once the control system experiences signal interference or the sensor drifts, it can easily lead to the tool clamping position of the tool magazine and the tool clamping mechanism of the spindle box failing to align accurately, resulting in tool change failure.

[0008] 4) Slow response speed, affecting machining cycle time: Due to the long transmission chain and large inertia of moving parts, the operating speed of traditional tool changing devices is limited, and the tool changing process takes a long time, becoming one of the bottlenecks restricting the improvement of overall machine machining efficiency. Especially in the machining of small parts with frequent tool changes, the tool changing time accounts for a large proportion of the total machining time, and its impact on production efficiency is more prominent.

[0009] 5) Limited clamping methods and poor adaptability: Many traditional tool holder mechanisms use purely mechanical clamping methods. For tools of different specifications or materials, it is difficult to achieve a good balance between clamping force and protection of the tool surface. Furthermore, the clamping stability is insufficient for small-diameter tools or special tools.

[0010] Therefore, in order to address the above problems, there is an urgent need to develop a tool changing device that is structurally simplified, occupies little space, has high positioning accuracy, fast response speed, can effectively resist the effects of mechanical wear, and has good clamping adaptability, so as to meet the development needs of modern high-precision and high-efficiency CNC machine tools. Summary of the Invention

[0011] The purpose of this invention is to address the shortcomings of existing technologies by proposing a device for changing cutting tools. Through innovative structural design, this device aims to solve the technical problems of traditional devices, such as complex structure, large space occupation, insufficient alignment accuracy, slow response speed, and susceptibility to wear.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] A device for changing cutting tools includes a tool magazine, which is a circular disc structure. A motor is fixedly installed at the center of the tool magazine, a mounting plate is provided above the motor, and a spindle box is provided at the outer edge of the tool magazine.

[0014] Furthermore, the outer edge of the tool magazine is evenly provided with multiple tool clamping positions along the circumferential direction, and the spindle box corresponds to one of the tool clamping positions. The spindle box has a cuboid structure, and its top is connected to an external drive device.

[0015] Furthermore, a tool clamping mechanism is provided at the bottom of the spindle box. The tool clamping mechanism is a cylindrical structure with its axis parallel to the length direction of the bottom of the spindle box and coincident with the axis of the tool clamping position.

[0016] Furthermore, the tool clamping mechanism includes an axially movable drive rod, with a gripper at the front end of the drive rod and the rear end of the drive rod connected to a power unit. The drive rod and the gripper are mechanically linked through an internal linkage mechanism.

[0017] Furthermore, a guide sleeve is provided around the outer periphery of the tool clamping mechanism, the guide sleeve is fixed on the inner wall of the spindle box, and an interface is provided at the rear end of the tool clamping mechanism.

[0018] Furthermore, a support base is provided at the bottom of the tool magazine. The support base has a ring structure, and its inner diameter is adapted to the outer diameter of the tool magazine. The tool magazine is rotatably supported on the support base.

[0019] Furthermore, the mounting plate is a plate-shaped structure, with its bottom corresponding to the top of the motor, and multiple mounting holes are provided on the mounting plate.

[0020] Furthermore, at the bottom end of the spindle box, corresponding to the front end of the tool holder mechanism, there is an inwardly recessed clearance groove, the shape of which is adapted to the shape of the gripper.

[0021] Furthermore, the power unit is the main shaft, the housing of the power unit is fixedly connected to the rear end of the main shaft box, and its telescopic rod is connected to the rear end of the drive rod.

[0022] Furthermore, the gripper is cylindrical and has an adsorption structure inside. The rear end of the gripper is slidably engaged with the drive head at the front end of the drive rod.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. Extremely compact structure and high space utilization: This invention integrates the motor driving the tool magazine rotation directly into the center of the tool magazine, abandoning the traditional side-mounted motor and transmission mechanism (such as gears or synchronous belts), greatly reducing the radial dimension of the device. Simultaneously, the tool clamping mechanism is cleverly built into the bottom of the spindle box, forming a concentric stacked structure of "motor-tool magazine-spindle box," resulting in an exceptionally compact layout. This frees up valuable space for the arrangement of other machine tool components, making it particularly suitable for five-axis machining centers or small precision machine tools with stringent space requirements.

[0025] 2. Achieving "Zero-Transmission" High-Precision Direct Tool Change: By placing the tool magazine motor in the center, backlash and errors in intermediate transmission links are eliminated. The indexing and positioning accuracy of the tool magazine is directly guaranteed by the motor encoder, resulting in rapid response. The spindle box only needs to move vertically. The axis of the tool clamping mechanism is designed to coincide with the axis of the tool clamping position. Combined with the high-precision guidance of the guide sleeve, the "what you see is what you get" tool clamping action is achieved, fundamentally solving the problem of decreased positioning accuracy caused by long transmission chains and accumulated wear in traditional devices.

[0026] 3. Fully closed-loop pure mechanical feedback with strong anti-interference capability: The clamping and releasing actions of the tool holder mechanism are achieved by the spindle driving the grippers through a precision mechanical linkage structure. This process does not rely on unstable factors such as air pressure fluctuations or hydraulic oil temperature changes, ensuring constant and reliable clamping force. The spindle position feedback can interlock with the spindle's tool release and pull detection, realizing fully closed-loop mechanical status monitoring and greatly improving the safety and reliability of the tool changing process.

[0027] 4. Modular design for easy maintenance and expansion: The tool holder mechanism is installed as an independent modular unit inside the spindle box and connected to the outside via rear-end interfaces (electrical and mechanical). When changing tool types or performing maintenance, it can be quickly disassembled and reassembled, significantly reducing downtime. This modular design also facilitates the serialization and expansion of the device on different machine tool models.

[0028] 5. Dual Clamping Protection for Enhanced Adaptability: The grippers feature a cylindrical design with an internal adsorption structure, providing dual protection through "mechanical clamping + vacuum adsorption." For conventional cutting tools, mechanical clamping force plays a primary role; for micro-diameter tools, brittle material tools, or tools requiring special protection, the adsorption structure provides a more flexible clamping force, preventing marks or damage. The sliding meshing structure ensures smooth power transmission and centering, further enhancing clamping reliability. Attached Figure Description

[0029] Figure 1 A schematic diagram of the overall structure of a tool changing device provided by the present invention;

[0030] Figure 2 A schematic diagram of the bottom structure of the tool magazine of a tool changing device provided by the present invention;

[0031] Figure 3 A schematic diagram of a tool magazine structure for a tool changing device provided by the present invention;

[0032] Figure 4 A schematic diagram of the spindle box structure of a tool changing device provided by the present invention;

[0033] Figure 5 A schematic diagram of a tool clamping mechanism for a tool changing device provided by the present invention;

[0034] Figure 6 This is a schematic diagram of the side planar structure of a tool clamping mechanism for a tool changing device provided by the present invention.

[0035] Legend: 1. Tool magazine; 2. Motor; 3. Mounting plate; 4. Spindle box; 5. Tool clamping mechanism; 6. Support base; 11. Tool clamping position; 31. Mounting hole; 41. Clearance groove; 51. Drive rod; 52. Clamping jaw; 53. Power unit; 54. Guide sleeve; 55. Interface. Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] To facilitate understanding of the present invention, a more comprehensive description of the invention will be provided below with reference to relevant embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be more thorough and complete.

[0038] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0040] Example 1

[0041] like Figure 1-6As shown, the present invention provides a tool changing device. Its core design concept lies in the high integration of the power source and the actuator to minimize space occupation and maximize transmission efficiency. The device mainly includes a tool magazine 1, a motor 2, a mounting plate 3, a spindle box 4, a tool clamping mechanism 5, and a support base 6. The tool magazine 1 has a circular disc structure and serves as a carrier for storing tools. The motor 2 is fixedly installed in the center of the tool magazine 1, and the mounting plate 3 is located above the motor 2. The spindle box 4 is located at the outer edge of the tool magazine 1. This layout places the power source motor in the center and the spindle box 4, which performs the tool changing action, on the outer edge, forming a symmetrical structure that rotates around the center, resulting in uniform force distribution and smooth rotation.

[0042] Example 2

[0043] like Figure 1-3 As shown, multiple tool clamping positions 11 are evenly arranged along the circumference of the outer edge of the tool magazine 1 to accommodate tools. Each tool clamping position 11 typically employs an elastic sleeve or U-groove structure to stably clamp the tool shank, ensuring that the tool will not loosen or wobble during the rotation of the tool magazine 1. The spindle box 4 corresponds to one of the tool clamping positions 11 located at the tool changing station. This position is precisely set as the tool changing point. The spindle box 4 is a vertically arranged cuboid structure with a flange with a positioning stop on its top for fixed connection to an external vertical drive device, such as a slide driven by a ball screw pair. During the tool changing process, the external drive device drives the spindle box 4 to perform precise vertical lifting and lowering movements to achieve docking and separation with the tool.

[0044] Inside the spindle box 4, at its bottom, is a horizontally mounted tool clamping mechanism 5 for performing tool gripping and releasing actions. The tool clamping mechanism 5 is a precision-machined cylindrical component, a shape that facilitates precise positioning and installation inside the spindle box 4. Its horizontal axis is designed to be parallel to the length direction of the bottom of the spindle box 4. More importantly, this axis must be strictly coincident with the axis of the tool clamping position 11 in the tool changing station. This is the geometric basis for achieving high-precision tool changing, ensuring that the tool clamping mechanism 5 can accurately align with the center of the tool when extending to grip it, avoiding skewness.

[0045] like Figure 4-6 As shown, the tool clamping mechanism 5 includes a drive rod 51 capable of high-precision axial movement within its housing. A gripper 52 for holding the tool is mounted at the front end of the drive rod 51. The rear end of the drive rod 51 is connected to a power unit 53 that provides power to it. The drive rod 51 and the gripper 52 are mechanically coupled through an internal precision linkage mechanism, converting the axial linear motion of the drive rod 51 into the clamping or releasing action of the gripper 52. This purely mechanical linkage mechanism, such as a linkage mechanism or a swashplate mechanism, has the advantages of simple structure, direct response, high transmission efficiency, and no hysteresis.

[0046] To ensure the absolute linearity and guiding accuracy of the reciprocating motion of the drive rod 51, a precision guide sleeve 54 is fitted around the outer periphery of the tool holder mechanism 5. This guide sleeve 54 is made of wear-resistant copper alloy or high-hardness steel, and its inner hole forms a precise sliding fit pair (e.g., H7 / g6) with the outer circle of the drive rod 51. The guide sleeve 54 is precisely fitted into the bottom inner wall of the spindle box 4 and fixed by a gland and screws, thus providing stable and reliable support and guidance for the movement of the tool holder mechanism 5. At the rear end of the tool holder mechanism 5, an interface 55 for connecting the power source and control signals is provided. This interface 55 varies depending on the selected power unit 53 and can be an electric, pneumatic, or hydraulic quick-connect coupling and electrical connector, facilitating modular disassembly and maintenance.

[0047] like Figure 2 As shown, to stably support the entire rotating tool magazine 1, an annular support base 6 is provided at the bottom of the tool magazine 1. The support base 6 is a precision annular casting or welded part with a mounting flange, the inner diameter of which is adapted to the outer diameter of the tool magazine 1. A high-precision rolling bearing, such as a crossed roller bearing, is usually installed between the two, allowing the tool magazine 1 to rotate smoothly and with low friction supported on the support base 6. The flange of the support base 6 is fixed to the worktable or machine tool base with bolts, providing a stable foundation for the entire tool changing device.

[0048] like Figure 1 As shown, the mounting plate 3 is a high-strength rectangular plate structure, with its bottom fastened to the top end face of the motor 2 by multiple high-strength bolts. The mounting plate 3 has multiple through mounting holes 31, which are used to connect the entire tool changer as a complete independent module to the machine tool bed, column, or dedicated tool magazine bracket by bolts. This design makes the installation and leveling of the device very convenient, while also enhancing the overall structural stability.

[0049] Based on Example 1, this example optimizes the cooperation structure between the tool holder mechanism 5 and the spindle box 4, as well as the specific implementation of the power unit 53.

[0050] like Figure 4-6 As shown, at the bottom of the spindle box 4, corresponding to the front end of the tool holder mechanism 5, there is an inwardly recessed clearance groove 41. The shape of the clearance groove 41 is adapted to the shape of the gripper 52. When the gripper 52 performs the action of gripping or releasing the tool, the gripper 52 may need to extend or open. The clearance groove 41 provides sufficient movement space for the gripper 52, avoiding movement interference with the bottom of the spindle box 4. This allows the spindle box 4 to be designed closer to the tool magazine 1, further shortening the distance from the spindle center to the tool magazine 1, optimizing the overall layout, and protecting the delicate gripper 52 mechanism from accidental bumps.

[0051] The power unit 53 preferably uses a highly integrated spindle with good control precision. The spindle housing is precisely positioned and fixedly connected to the rear end face of the spindle box 4 via a flange. The front end of the spindle's telescopic rod is coaxially fixedly connected to the rear end of the drive rod 51 of the tool holder mechanism 5 via a coupling or directly. The spindle has a built-in high-resolution encoder and brake, which can receive commands from the CNC system and precisely control the extension length, speed, and thrust of the telescopic rod. When gripping a tool, the CNC system issues a command, and the spindle drives the drive rod 51 to move to the designated position, so that the gripper 52 completes the gripping action. The encoder provides feedback on the actual position, achieving precise position control and status monitoring.

[0052] like Figure 5-6 As shown, the gripper 52 is cylindrical in shape, which facilitates smooth movement within the guide sleeve 54 or the clearance groove 41. Its core innovation lies in the internal adsorption structure of the gripper 52. This adsorption structure can be a gas passage and adsorption hole connected to an external vacuum system. When the gripper 52 contacts the tool shank, vacuum adsorption can be activated, forming a dual locking mechanism of "mechanical clamping + vacuum adsorption." For some small-diameter tools, brittle material tools, or tools requiring extremely high surface precision, flexible gripping can be achieved primarily through adsorption force, avoiding surface indentations or damage that may be caused by purely mechanical clamping.

[0053] Meanwhile, the rear end of the gripper 52 is connected to the drive head at the front end of the drive rod 51 by a sliding engagement. This engagement method, for example, with the drive head designed as a multi-prism or spline structure and the rear end of the gripper designed as a matching groove, allows the drive rod 51 to transmit not only axial push and pull forces but also a certain amount of torque. At the same time, it allows for a slight radial float between the two, which plays a role in automatic centering. This further ensures the perfect alignment of the gripper 52 and the tool, improving the success rate and accuracy of tool changing.

[0054] Workflow of the present invention: When using a device for changing tools, before starting automatic tool changing, the CNC system issues a command, the motor 2 drives the tool magazine 1 to rotate, and quickly and accurately delivers the target tool required for the next process to the tool changing station, so that the tool clamping position 11 where the tool is located is aligned with the tool clamping mechanism 5 below the spindle box 4.

[0055] Subsequently, the external vertical drive device is activated, driving the spindle box 4 to descend to the tool changing position, so that the tool holder mechanism 5 is aligned with the shank of the target tool.

[0056] At this time, the spindle of the power unit 53 receives the tool gripping command, its telescopic rod extends, and pushes the drive rod 51 to move precisely forward along the guide sleeve 54. The drive rod 51 drives the gripper 52 to move through the internal linkage mechanism. According to the design, it may be open or pre-positioned in a gripping state.

[0057] When the tool holder mechanism 5 is in position, the gripper 52 holds the tool shank, and at the same time the internal adsorption structure is activated to form a double lock.

[0058] After confirming that the tool has been reliably clamped, the external drive device drives the spindle box 4 to rise, vertically pulling the tool out of the tool clamping position 11 of the tool magazine 1, completing the tool gripping action. The tool release action is the reverse of the above process. The gripper 52 first releases the mechanical clamping force and then cuts off the vacuum adsorption to ensure that the tool returns to its position smoothly.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A device for changing cutting tools, comprising a tool magazine (1), characterized in that: The tool magazine (1) is a circular disc structure. A motor (2) is fixedly installed in the center of the tool magazine (1). A mounting plate (3) is provided above the motor (2). A spindle box (4) is provided at the outer edge of the tool magazine (1).

2. The device for changing cutting tools according to claim 1, characterized in that: The tool magazine (1) has multiple tool clamping positions (11) evenly arranged along the circumferential direction on its outer edge. The spindle box (4) corresponds to one of the tool clamping positions (11). The spindle box (4) is a cuboid structure, and its top is connected to an external drive device.

3. The device for changing cutting tools according to claim 1, characterized in that: The spindle box (4) is provided with a tool clamping mechanism (5) at the bottom of its interior. The tool clamping mechanism (5) is a cylindrical structure with its axis parallel to the length direction of the bottom of the spindle box (4) and coincides with the axis of the tool clamping position (11).

4. The device for changing cutting tools according to claim 3, characterized in that: The tool clamping mechanism (5) includes an axially movable drive rod (51), with a gripper (52) at the front end of the drive rod (51) and the rear end of the drive rod (51) connected to the power unit (53). The drive rod (51) and the gripper (52) are mechanically linked through an internal linkage mechanism.

5. The device for changing cutting tools according to claim 3, characterized in that: The tool clamping mechanism (5) is fitted with a guide sleeve (54) on its outer periphery. The guide sleeve (54) is fixed on the inner wall of the spindle box (4). The tool clamping mechanism (5) has an interface (55) at its rear end.

6. The device for changing cutting tools according to claim 1, characterized in that: The bottom of the tool magazine (1) is provided with a support base (6). The support base (6) is a ring structure, and its inner diameter is adapted to the outer diameter of the tool magazine (1). The tool magazine (1) is rotatably supported on the support base (6).

7. The device for changing cutting tools according to claim 1, characterized in that: The mounting plate (3) is a plate-shaped structure, and its bottom is installed corresponding to the top of the motor (2). The mounting plate (3) has multiple mounting holes (31).

8. The device for changing cutting tools according to claim 3, characterized in that: At the bottom end of the spindle box (4), at the position corresponding to the front end of the tool clamping mechanism (5), there is an inwardly recessed relief groove (41), the shape of which is adapted to the shape of the clamping claw (52).

9. The device for changing cutting tools according to claim 4, characterized in that: The power unit (53) is the main shaft. The housing of the power unit (53) is fixedly connected to the rear end of the main shaft box (4), and its telescopic rod is connected to the rear end of the drive rod (51).

10. The device for changing cutting tools according to claim 4, characterized in that: The gripper (52) is cylindrical and has an adsorption structure inside. The rear end of the gripper (52) is slidably engaged with the drive head at the front end of the drive rod (51).

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