A method and device for preventing collisions of machine tool swivel spindles

Abstract

This invention discloses a method and device for preventing collisions of a machine tool swivel spindle. The method includes detecting the real-time pressure value of the collision during the spindle's upward movement; when the real-time pressure value reaches a preset critical pressure value, controlling the Z-axis motor to apply emergency braking; and / or, when the real-time pressure value does not reach the preset critical pressure value, if the working stroke of the Z-axis motor driving the swivel spindle upward reaches a second soft limit, determining whether the swivel spindle is in a non-vertical state; if so, sending an alarm prompt and simultaneously controlling the Z-axis motor to apply emergency braking. This invention, by detecting the real-time pressure value of the collision during the Z-axis upward movement and detecting whether the swivel spindle is rising vertically after the Z-axis motor's working stroke reaches the second soft limit, controls the emergency braking function of the Z-axis motor, thereby achieving spindle collision prevention and mitigating the impact of collisions when they are unavoidable.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tool technology, and in particular to a method and device for preventing collisions with the spindle of a machine tool. Background Technology

[0002] With the development of science and technology and the progress of manufacturing technology, the requirements for product quality and variety are increasing, and the proportion of medium and small batch production is increasing significantly, prompting CNC machine tools to continuously develop towards high efficiency, high quality, high flexibility and low cost; among them, the development trend of five-axis machining centers is particularly intense.

[0003] Currently, five-axis machining centers can be broadly classified into two categories: one is a swivel spindle where the AC axis and the main spindle are integrated, and the other is a single spindle paired with an AC axis cradle. Five-axis linkage CNC machine tools are high-tech, high-precision machine tools specifically designed for machining complex curved surfaces. Five-axis linkage involves the mechanical linkage of five coordinate systems, and improper use can lead to the risk of impact. An impacted spindle directly affects the spindle's machining accuracy and production cycle time, causing direct economic losses to the user. Summary of the Invention

[0004] In order to overcome the above-mentioned disadvantages of existing machine tool machining processes, such as the impact safety hazard of the swivel spindle, the direct loss of machining accuracy after impact, and the damage to the swivel spindle bearings in severe cases, resulting in economic losses due to disassembly, repair or replacement, the purpose of this invention is to provide a method and device for preventing collisions of machine tool swivel spindles.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for preventing collisions of a machine tool swivel spindle, comprising:

[0006] Detect the real-time pressure value of the impact during the upward movement of the oscillating head spindle;

[0007] When the real-time pressure value reaches the preset critical pressure value, the Z-axis motor is controlled to brake urgently; and / or, when the real-time pressure value does not reach the preset critical pressure value, if the working stroke of the Z-axis motor driving the swing head spindle to rise reaches the second soft limit, it is determined whether the swing head spindle is in a non-vertical state. If so, an alarm prompt is sent, and the Z-axis motor is controlled to brake urgently.

[0008] As a further improvement of the present invention: a first pressure detection switch is installed at the bearing of the oscillating head spindle, the first pressure detection switch is connected to the machine tool CNC system, and the machine tool CNC system is provided with a first preset critical pressure value and a second preset critical pressure value.

[0009] As a further improvement of the present invention: a second pressure detection switch is installed on the rear end of the Z-axis motor, and the second pressure detection switch is connected to the CNC system of the machine tool.

[0010] As a further improvement of the present invention: the Z-axis motor is connected to a brake device.

[0011] As a further improvement of the present invention, it also includes: an anti-collision ring installed around the spindle box.

[0012] As a further improvement of the present invention: the non-vertical state includes the state in which the A axis of the oscillating head spindle is perpendicular to the Z axis and the state in which the B axis of the oscillating head spindle is perpendicular to the Z axis.

[0013] As a further improvement of the present invention: the machine tool CNC system is provided with a first soft limit and a second soft limit, the first soft limit being used to characterize the maximum working stroke of the Z-axis motor, and the second soft limit being the anti-collision detection stroke.

[0014] As a further improvement of the present invention: when the working stroke of the Z-axis motor is detected to exceed the first soft limit, the Z-axis motor is controlled to brake urgently and an alarm is triggered.

[0015] As a further improvement of the present invention: the non-vertical state includes the state in which the A-axis or B-axis of the oscillating head spindle is not in the vertical state of the Z-axis.

[0016] Based on the same inventive concept, the present invention provides a machine tool swivel spindle anti-collision device, comprising:

[0017] The pressure detection module is used to detect the real-time pressure value of the impact during the upward movement of the oscillating head spindle;

[0018] The judgment module is used to judge whether the real-time pressure value has reached the preset critical pressure value and obtain a first judgment result. It is also used to judge whether the swing head spindle is in a non-vertical state when the first judgment result is negative and the working stroke of the Z-axis motor reaches the second soft limit and obtain a second judgment result.

[0019] The processing module is used to control the Z-axis motor to brake urgently when the first judgment result is yes; it is also used to send an alarm prompt and synchronously control the Z-axis motor to brake urgently when the second judgment result is yes.

[0020] As a further improvement of the present invention, the processing module is also used to control the Z-axis motor to brake urgently and issue an alarm when the working stroke of the Z-axis rise is detected to exceed the first soft limit.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] This invention detects the real-time pressure value experienced by the oscillating head spindle during its ascent. When the detected real-time pressure value reaches a preset critical pressure value, the Z-axis motor is controlled to brake urgently, preventing the oscillating head spindle from continuing to extend into the spindle box and avoiding a collision between the oscillating head spindle and the spindle box.

[0023] In addition, when the Z-axis motor's upward stroke triggers the second soft limit, it detects that the oscillating head spindle is not in a vertical state. It controls the Z-axis motor to brake urgently and gives an alarm prompt to prevent operator negligence or failure to adjust the state of the oscillating head spindle in time during automatic mode, which could cause the oscillating head spindle to rise in a non-vertical state, resulting in the Z-axis motor driving the oscillating head spindle to rise and extend into the spindle box, causing spindle impact damage. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating a method for preventing collisions with the spindle of a machine tool swivel head according to the present invention.

[0025] Figure 2 This is a flowchart illustrating one embodiment of a machine tool spindle anti-collision method according to the present invention.

[0026] Figure 3 This is a flowchart illustrating one embodiment of a machine tool spindle anti-collision method according to the present invention.

[0027] Figure 4 This is a flowchart illustrating one embodiment of a machine tool spindle anti-collision method according to the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0029] In order to solve the technical problems in the prior art, the present invention will now be further described in conjunction with the accompanying drawings and embodiments:

[0030] like Figures 1-4 As shown, this invention discloses a method for preventing collisions of a machine tool swivel spindle. On one hand, it detects the real-time pressure state of the swivel spindle colliding with the spindle box, and performs an emergency stop when the detected pressure value reaches a critical state. On the other hand, it sets a Z-axis rise threshold value within the machine tool's CNC system. When the Z-axis threshold value is triggered, an emergency brake is applied to prevent operator negligence or failure to adjust the swivel spindle's state in time during automatic operation, which could result in the A-axis of the swivel spindle rising perpendicular to the Z-axis or the swivel spindle rising in a non-vertical state, leading to the Z-axis motor driving the swivel spindle to rise and extend into the spindle box, causing a spindle impact. The method specifically includes:

[0031] S10: Detects the real-time pressure value of the collision during the upward movement of the oscillating head spindle;

[0032] When the real-time pressure value reaches the preset critical pressure value, it indicates that the oscillating head spindle is not in a vertical state and is extending into the spindle box. It is possible that the A-axis of the oscillating head spindle is in a vertical state with the Z-axis. At this time, the oscillating head spindle is not fully extended into the spindle box, but it also indicates that if the oscillating head spindle continues to extend, it will inevitably cause a serious impact. After the impact, the spindle accuracy will be lost. In severe cases, the bearing of the oscillating head spindle will be damaged, and disassembly, repair or replacement will bring greater economic losses. Therefore, emergency braking of the Z-axis motor can effectively prevent the oscillating head spindle from continuing to extend into the spindle box.

[0033] In the above example, the real-time pressure value includes a first real-time pressure value and a second real-time pressure value. Correspondingly, the machine tool CNC system is equipped with a first preset critical pressure value and a second critical pressure value.

[0034] In some embodiments, a first pressure detection switch is installed at the bearing of the oscillating head spindle. The first pressure detection switch is connected to the machine tool CNC system signal and transmits the detected pressure signal to the machine tool CNC system in real time.

[0035] In the above example, the first pressure detection switch detects the first real-time pressure value. The first pressure detection switch is used to detect the real-time pressure state of a collision that has occurred or is occurring when the spindle is carrying a tool. When the first real-time pressure value detected by the first pressure detection switch reaches the first preset critical pressure value, it indicates that the oscillating spindle carrying the tool has collided with the peripheral components of the spindle box at the moment of detection, including collisions between the spindle and the Y-axis beam, between the spindle and the workpiece, and between the tooling.

[0036] In some embodiments, a second pressure detection switch is installed on the rear end of the Z-axis motor, and the second pressure detection switch is connected to the machine tool CNC system.

[0037] In the above example, the second pressure detection switch detects the second real-time pressure value. When the oscillating head spindle is not carrying a tool, and when the first pressure detection switch does not detect a pressure change, but the oscillating head spindle carries a tool and is not in a vertical state, the second pressure detection switch is used to detect the real-time pressure value state of collision with the spindle box. When the second real-time pressure value reaches the second preset critical pressure value, it indicates that the oscillating head spindle directly collides with the spindle box, including the collision between the oscillating head spindle motor and the spindle box.

[0038] S20: When the real-time pressure value reaches the preset critical pressure value, control the Z-axis motor to brake urgently;

[0039] And / or, S210: When the real-time pressure value does not reach the preset critical pressure value, if the working stroke of the Z-axis motor driving the swing head spindle to rise reaches the second soft limit, S211: Determine whether the swing head spindle is in a non-vertical state. If so, send an alarm prompt and synchronously control the Z-axis motor to brake urgently.

[0040] It should be noted that when a pressure change is detected during the process of the Z-axis motor driving the spindle box to raise the oscillating head spindle, it does not mean that the oscillating head spindle has been seriously damaged by an impact. Only when the real-time pressure value reaches the preset critical pressure value does it indicate that the oscillating head spindle has collided. At this time, it is necessary to urgently stop the Z-axis motor from continuing to drive the oscillating head spindle to rise, in order to prevent the oscillating head spindle from being damaged more seriously.

[0041] Because the machining process of five-axis linkage CNC machine tools has various impact safety hazards, the five-axis linkage CNC machine tools currently on the market, including the five-axis structural components, have some relatively heavy spindle boxes equipped with balance cylinder devices, which are mainly used for the Z-axis motor to drive the spindle box to move quickly and to balance when it slides down.

[0042] The spindle box is used to fix the swivel head spindle and various oil pipes, air lines, etc. The Z-axis motor drives the spindle box, thereby driving the swivel head spindle to move up and down along the Z-axis.

[0043] In some implementations, a Z-axis motor with a holding brake is used to ensure the emergency braking function of the Z-axis motor.

[0044] In the above example, the Z-axis motor with a brake function prevents sudden situations such as the spindle box slipping. During the anti-collision monitoring of the oscillating spindle, when the oscillating spindle is impacted, the Z-axis motor brakes to prevent further fall.

[0045] It should be added that the design of some swivel spindles in existing five-axis CNC machine tools has to shorten the length of the spindle box due to factors such as stroke and crossbeam weight. This means that part of the swivel spindle needs to extend into the spindle box, otherwise the Z-axis machining stroke will not meet the requirements. However, this brings problems: when the A-axis is perpendicular to the Z-axis, or when the swivel spindle is not vertical and extends into the spindle box, it will inevitably cause impact to the swivel spindle. If not controlled, it will seriously damage the bearings of the swivel spindle.

[0046] In some embodiments, a bumper ring is installed around the spindle box. This bumper ring is an existing structure and will not be described in detail herein.

[0047] In the above example, on the one hand, when the oscillating head spindle is in a non-vertical state and is driven by the Z-axis motor to extend into the spindle box, the added anti-collision ring can effectively prevent the oscillating head spindle from directly colliding with the surrounding components of the spindle box, playing a certain anti-collision buffering role, and protecting the oscillating head spindle and spindle box from impact damage to the greatest extent.

[0048] On the other hand, the anti-collision ring, in conjunction with the first and second pressure detection switches, causes a change in pressure at the bearing of the swivel head spindle when the spindle comes into contact with the anti-collision ring. The machine tool CNC system compares the detected real-time pressure value with the preset critical pressure value to determine the situation and then controls the brake function of the Z-axis motor. Instead of directly detecting the pressure change caused by the direct contact between the swivel head spindle and the spindle box, the system reflects the collision situation when the swivel head spindle is not in a vertical state by the pressure change when it comes into contact with the anti-collision ring, thereby effectively preventing damage caused by the impact of the swivel head spindle.

[0049] In other words, with the combined action of the first pressure detection switch, the second pressure detection switch, and the anti-collision ring, the insertion state of the oscillating head spindle into the spindle box can be detected as follows: whether the spindle spindle is in a vertical state, or whether the A-axis of the oscillating head spindle is perpendicular to the Z-axis, or whether the A-axis and Z-axis of the oscillating head spindle are at an angle.

[0050] Furthermore, the structure of the first pressure detection switch, the second pressure detection switch, and the anti-collision ring in this invention can also be used to detect whether the B-axis and Z-axis of the oscillating head spindle are perpendicular, or whether the B-axis and Z-axis of the oscillating head spindle are at an angle. In other words, in this invention, the non-vertical state of the oscillating head spindle includes both the A-axis not being vertical to the Z-axis and the B-axis not being vertical to the Z-axis.

[0051] The normal operation is when the oscillating head spindle is in a vertical position when it enters the spindle box. If the oscillating head spindle is not in a vertical position when it extends into the spindle box, a spindle collision event will occur.

[0052] The A-axis is the oscillating spindle rotating around the Y-axis, and the B-axis is the oscillating spindle rotating around the X-axis. For the CA-type five-axis linkage CNC machine tool, an emergency braking is achieved by setting a first pressure detection switch at the spindle bearing and installing anti-collision rings around the spindle box, thereby effectively preventing damage caused by spindle impact.

[0053] In some implementations, the working stroke of the Z-axis motor in the machine tool CNC system is pre-defined by a first soft limit and a second soft limit.

[0054] The first soft limit is mainly used to prevent the Z-axis motor from driving the spindle box to drive the oscillating head spindle to rise at high speed, which would exceed the total stroke and trigger an alarm, thereby achieving emergency braking.

[0055] In a specific example, the Z-axis motor's working stroke exceeds a first soft limit, triggering an emergency braking maneuver for the Z-axis motor. The first soft limit represents the maximum working stroke of the Z-axis motor.

[0056] The second soft limit is used to prevent the spindle from colliding with the left and right arms of the spindle box during the vertical ascent of the A-axis and Z-axis; the first soft limit is to prevent the Z-axis from overtravel.

[0057] In a specific example, when the working stroke of the Z-axis motor driving the oscillating head spindle to rise exceeds the second soft limit, an anti-collision judgment logic is performed to determine whether the oscillating head spindle is in a vertical or perpendicular state of the Z-axis, and whether the oscillating head spindle is at an angle to the Z-axis. Based on the judgment result, it is determined whether there is a collision between the oscillating head spindle and the spindle box.

[0058] To further clarify, a vertical Z-axis indicates that the direction of the central axis of the oscillating head spindle is consistent with the Z-axis direction; a perpendicular A-axis to the Z-axis indicates that the central axis of the oscillating head spindle is perpendicular to the Z-axis direction; and a non-vertical state indicates that there is an angle between the central axis of the oscillating head spindle and the Z-axis direction.

[0059] In some implementations, after the Z-axis motor is braked in an emergency, the Z-axis must not continue to rise and an alarm will be triggered. It is necessary to adjust the A-axis of the swivel head spindle to the vertical position of the Z-axis through the machine tool CNC system; otherwise, no axis can be moved.

[0060] In some implementations, after the tool is mounted on the swivel spindle, a tool setting operation and anti-collision detection are performed. The tool setting operation uses a tool setting device to set the tool and provide feedback information, while the probe detects the shape of the workpiece and provides feedback information. In manual or automatic mode, the machine tool CNC system automatically determines whether there is interference between the tool and the workpiece on the swivel spindle. If so, an alarm is triggered to indicate interference and an emergency brake is applied. The machining information is then re-edited and the tool setting operation is performed again.

[0061] Furthermore, after the tool setting operation of the machine tool CNC system is completed, the machine tool CNC system performs anti-collision detection. Specifically, when the real-time pressure value detected at the bearing of the swivel spindle reaches the preset critical pressure value, the collision situation of the swivel spindle is detected to determine whether the swivel spindle is normal. If the swivel spindle is displayed as normal, the machining information is re-edited and the tool setting operation is performed again; if the swivel spindle is displayed as abnormal, the anti-collision detection ends.

[0062] The five-axis system is equipped with a corresponding tool setter to detect tool length, radius and other related information and upload it to the CNC system. It is also equipped with a corresponding probe to detect the shape of the workpiece. By setting the origin of the spindle nose and then performing the measured tool compensation, the overall machining information is fully fed back.

[0063] Furthermore, when the real-time pressure value detected at the bearing of the oscillating head spindle does not reach the preset critical pressure value, the oscillating head spindle is detected during the Z-axis rising process. When the working stroke of the Z-axis motor reaches the second soft limit, the second anti-collision detection program is started to detect whether the oscillating head spindle is vertically extended into the spindle box. If not, it indicates that the A-axis or B-axis is perpendicular to the Z-axis or at an angle. The Z-axis motor is controlled to brake urgently, and the Z-axis alarm prompts that the A-axis or B-axis must be vertical.

[0064] The present invention also provides a machine tool swivel spindle anti-collision device, comprising:

[0065] The pressure detection module is used to detect the real-time pressure value of the impact during the upward movement of the oscillating head spindle;

[0066] The judgment module is used to judge whether the real-time pressure value has reached the preset critical pressure value and obtain a first judgment result. It is also used to judge whether the swing head spindle is in a non-vertical state when the first judgment result is negative and the working stroke of the Z-axis motor reaches the second soft limit and obtain a second judgment result.

[0067] The processing module is used to control the Z-axis motor to brake urgently when the first judgment result is yes; it is also used to send an alarm prompt and synchronously control the Z-axis motor to brake urgently when the second judgment result is yes.

[0068] In some implementations, the processing module is further configured to control the Z-axis motor to brake urgently and issue an alarm when the working stroke of the Z-axis rises exceeds the first soft limit.

[0069] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preventing collisions with a machine tool swivel spindle, characterized in that, include: The real-time pressure value of the collision during the upward process of the oscillating head spindle is detected. A first pressure detection switch is installed at the bearing of the oscillating head spindle to detect the first real-time pressure value when the tool collides with the surrounding components. A second pressure detection switch is installed at the rear end of the Z-axis motor to detect the second real-time pressure value when the oscillating head spindle collides with the spindle box. When the first real-time pressure value reaches the first preset critical pressure value or the second real-time pressure value reaches the second preset critical pressure value, control the Z-axis motor to brake urgently. And / or, If the real-time pressure value does not reach the preset critical pressure value, and the working stroke of the Z-axis motor driving the swing head spindle to rise reaches the second soft limit, it is determined whether the swing head spindle is in a non-vertical state. If so, an alarm prompt is sent, and the Z-axis motor is simultaneously controlled to brake urgently.

2. The anti-collision method for a machine tool swivel spindle according to claim 1, characterized in that, The first pressure detection switch is connected to the machine tool CNC system.

3. The anti-collision method for a machine tool swivel spindle according to claim 1, characterized in that, The second pressure detection switch is connected to the machine tool CNC system.

4. The anti-collision method for a machine tool swivel spindle according to claim 1, characterized in that, The Z-axis motor is connected to a brake device.

5. A method for preventing collisions of a machine tool swivel spindle according to claim 4, characterized in that, Also includes: Anti-collision rings are installed around the spindle box.

6. A method for preventing collisions of a machine tool swivel spindle according to claim 1, characterized in that, The non-vertical state includes the state where the A-axis of the oscillating head spindle is perpendicular to the Z-axis and the state where the B-axis of the oscillating head spindle is perpendicular to the Z-axis.

7. A method for preventing collisions of a machine tool swivel spindle according to claim 3, characterized in that, The machine tool CNC system is equipped with a first soft limit and a second soft limit. The first soft limit is used to characterize the maximum working stroke of the Z-axis motor, and the second soft limit is the anti-collision detection stroke.

8. A method for preventing collisions of a machine tool swivel spindle according to claim 6, characterized in that, When the working stroke of the Z-axis motor is detected to exceed the first soft limit, the Z-axis motor is controlled to brake urgently and an alarm is triggered.

9. A machine tool swivel spindle anti-collision device, characterized in that, include: The pressure detection module is used to detect the real-time pressure value of the collision during the upward process of the oscillating head spindle. A first pressure detection switch is installed at the bearing of the oscillating head spindle to detect the first real-time pressure value when the tool collides with the surrounding components. A second pressure detection switch is installed on the rear end of the Z-axis motor to detect the second real-time pressure value when the oscillating head spindle collides with the spindle box. The judgment module is used to determine whether the first real-time pressure value reaches the first preset critical pressure value or the second real-time pressure value reaches the second preset critical pressure value, and to obtain a first judgment result. It is also used to determine whether the swing head spindle is in a non-vertical state when the first judgment result is negative and the working stroke of the Z-axis motor reaches the second soft limit, and to obtain a second judgment result. The processing module is used to control the Z-axis motor to brake urgently when the first judgment result is yes; it is also used to send an alarm prompt and synchronously control the Z-axis motor to brake urgently when the second judgment result is yes.

10. A machine tool swivel spindle anti-collision device according to claim 9, characterized in that, The processing module is also used to control the Z-axis motor to brake urgently and issue an alarm when it detects that the working stroke of the Z-axis rise exceeds the first soft limit.

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