Pneumatic counterweight device and numerical control machine tool

Abstract

The application discloses a kind of pneumatic counterweight device and numerical control machine tool, the numerical control machine tool includes a vertical moving component, pneumatic counterweight device includes pressure regulating device, pressure sensor, gas storage tank, cylinder and fixing piece, the pressure sensor is used to obtain the gas pressure of gas storage tank;The gas storage tank is used to provide cylinder gas source;The cylinder is connected between the vertical moving component and the fixing piece by cylinder support, and the cylinder applies upward thrust to the vertical moving component;The pressure regulating device is used to adjust the gas pressure of gas storage tank according to the counterweight of vertical moving component.The application reduces the wear of shaft system movement, improves the service life of moving shaft system components, machining accuracy and the safety of numerical control machine tool production.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tools, and particularly to a pneumatic counterweight device and a CNC machine tool. Background Technology

[0002] A CNC machine tool is a modern machining equipment that precisely manipulates the movement of a machine tool through digital control commands. Using pre-programmed computer programs, it performs high-precision, high-efficiency cutting, drilling, milling, and other machining operations on workpieces made of metals, plastics, and composite materials. It is a core foundation of intelligent manufacturing and high-end equipment manufacturing.

[0003] When a machine tool moves vertically, the load difference generated by the vertical axis during upward and downward acceleration is large due to the influence of gravity. In order to meet the rigidity and stability requirements of the moving parts of the machine tool under different motion modes, the initial design stage will consider selecting motors and transmission shafts with sufficiently large loads. Existing CNC machine tools have the defects of severe wear of vertical axis movement, high maintenance costs, and impact on the machining accuracy of the machine tool. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the existing CNC machine tool, such as severe wear of vertical axis movement, high maintenance cost and impact on machine tool machining accuracy. The present invention provides a pneumatic counterweight device and CNC machine tool that can reduce the wear of axis movement, improve the service life of moving axis components, machining accuracy and production safety of CNC machine tool.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] A pneumatic counterweight device for a CNC machine tool, the CNC machine tool including a vertically moving component, characterized in that the pneumatic counterweight device includes a pressure regulating device, a pressure sensor, an air tank, a cylinder, and a fixing component.

[0007] The pressure sensor is used to obtain the gas pressure of the gas storage tank;

[0008] The air storage tank is used to provide the air source for the cylinder;

[0009] The cylinder is connected between the vertically moving component and the fixed component via a cylinder bracket, and the cylinder applies an upward thrust to the vertically moving component.

[0010] The pressure regulating device is used to adjust the air pressure of the air storage tank according to the counterweight of the vertically moving component.

[0011] Preferably, the pneumatic counterweight device further includes a muffler, a one-way valve, a control line, and a manual valve. The pressure regulating device, pressure sensor, and manual valve are all located on the control line. One end of the control line is connected to the air supply line and the other end is connected to the air storage tank. The one-way valve is provided between the air supply line and the control line. The muffler is located at the exhaust port of the cylinder.

[0012] Preferably, the thrust applied by the cylinder to the vertically moving component is 50% to 80% of the counterweight of the vertically moving component; or,

[0013] The pressure regulating device is used to replenish the gas tank when the vertical moving part moves upward, and to exhaust the gas tank when the vertical moving part moves downward.

[0014] Preferably, the vertical moving component includes a moving beam, a sliding saddle, and a lead screw assembly. The moving beam is installed to the fixed component via the lead screw assembly, the lead screw assembly is connected to a lead screw motor, the lead screw motor is fixed to the fixed component via a motor mount, the moving beam moves vertically via the lead screw assembly, the sliding saddle moves left and right on the moving beam, the cylinder is installed on the moving beam, and the cylinder rod of the cylinder is fixed to the lower bottom surface of the fixed component.

[0015] Preferably, the exhaust port is located at the top of the cylinder, the air inlet port is located at the bottom of the cylinder, the piston of the cylinder is located between the air inlet port and the exhaust port, the piston is fixed to the cylinder rod, and the outer shells of the two cylinders are respectively fixed to both sides of the moving beam.

[0016] Preferably, the pressure regulating device includes a processing module and a control valve.

[0017] The processing module is used to obtain the position of the sliding saddle on the moving beam, and adjust the air pressure in the two cylinders according to the position using a control valve. The ratio of the air pressure in the two cylinders is inversely proportional to the ratio of the distance from the sliding saddle to both ends of the moving beam.

[0018] Preferably, the pneumatic counterweight device includes two air tanks, each connected to a corresponding cylinder. The processing module is used to adjust the air pressure of the first air tank connected to the first cylinder using a control valve. Where W is the counterweight of the vertical moving part, L is the length of the moving beam, x is the distance from the saddle to the end of the moving beam near the first cylinder, T is the pressure area of ​​the piston, and a is the coefficient of the counterweight factor and the friction factor.

[0019] The processing module is used to adjust the air pressure of the second air tank connected to the second cylinder. .

[0020] Preferably, the processing module is used to acquire the machining program data of the CNC machine tool, and to obtain the movement parameters of the moving beam from the machining program data. The x value of the next epoch in the movement parameters is used to obtain the air pressure value of the air tank in the current epoch. The epoch interval is generated according to the air tank replenishment efficiency and the moving speed of the sliding saddle.

[0021] Preferably, the pressure regulating device includes a processing module and a control valve.

[0022] The processing module is used to obtain the position of the sliding saddle on the moving beam, and adjust the opening amount of the control valve according to the position. The ratio of the opening amounts of the two control valves is proportional to the ratio of the distances from the sliding saddle to both ends of the moving beam.

[0023] The present invention also provides a CNC machine tool, characterized in that the CNC machine tool includes the pneumatic counterweight device described above.

[0024] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0025] The positive and progressive effects of this invention are as follows:

[0026] This invention reduces wear on the shaft system, increases the service life of moving shaft components, and improves the safety of CNC machine tool production. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the pneumatic counterweight device according to Embodiment 1 of the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of the CNC machine tool according to Embodiment 1 of the present invention. Detailed Implementation

[0029] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0030] Example 1

[0031] See Figure 1 , Figure 2 This embodiment provides a CNC machine tool.

[0032] The CNC machine tool includes a vertical moving part and a pneumatic counterweight device.

[0033] The pneumatic counterweight device includes a pressure regulating device 201, a pressure sensor 202, an air tank 203, a cylinder 204, and a fixing component 104.

[0034] The pressure sensor is used to obtain the gas pressure of the gas storage tank.

[0035] The gas storage tank is used to provide the gas source for the cylinder.

[0036] The cylinder is connected between the vertical moving component and the fixed component via a cylinder bracket 107, and the cylinder applies an upward thrust to the vertical moving component.

[0037] The fixing component is a support base.

[0038] The pressure regulating device is used to adjust the air pressure of the air storage tank according to the counterweight of the vertically moving component.

[0039] The pneumatic counterweight device also includes a silencer 205, a one-way valve 206, a control pipeline 207, and a manual valve 208.

[0040] The pressure regulating device 201, pressure sensor 202, manual valve 208, and pressure gauge 209 are all located on the control pipeline.

[0041] One end of the control line is connected to the gas supply line 210 and the other end is connected to the gas storage tank.

[0042] The one-way valve is provided between the air supply line and the control line, and the muffler is located at the exhaust port of the cylinder.

[0043] The pressure regulating device is used to replenish the gas tank when the vertical moving part moves upward, and to exhaust the gas tank when the vertical moving part moves downward.

[0044] When the vertically moving part moves upward, the gas at the top of the cylinder is discharged through the quick exhaust valve, and the air tank is quickly replenished through the air source to maintain the pressure of the air tank within a certain air pressure range; when it moves downward, the gas in the cylinder is quickly discharged to the air tank, and then discharged through the pressure regulating valve connected to the air tank to maintain the pressure of the air tank within a certain air pressure range.

[0045] In other embodiments, the thrust applied by the cylinder to the vertically moving component is 50% to 80% of the counterweight of the vertically moving component.

[0046] The counterweight of the vertical moving part includes the weight of the vertical moving part itself and the weight of the workpiece assembled with the vertical moving part.

[0047] The vertical moving component includes a moving beam 101, a sliding saddle 102, and a lead screw pair 103. A sliding bolster 105 is provided inside the sliding saddle 102.

[0048] The movable beam 101 is installed with the fixing component via a lead screw pair 103. The lead screw pair 103 is connected to a lead screw motor, and the lead screw motor is fixed to the fixing component via a motor mount 106.

[0049] The moving beam moves vertically via a lead screw pair, the sliding saddle moves left and right on the moving beam, the cylinder is mounted on the moving beam, and the cylinder rod 2041 of the cylinder 204 is fixed to the lower bottom surface 1041 of the fixing member 104.

[0050] The exhaust port is located at the top of the cylinder, the air inlet port is located at the bottom of the cylinder, the piston of the cylinder is located between the air inlet port 2042 and the exhaust port, the piston is fixed to the cylinder rod, and the outer shells of the two cylinders are respectively fixed to both sides of the moving beam.

[0051] In this embodiment, the machine tool ram moves back and forth along the slide saddle, and the slide saddle and ram move laterally left and right within the moving beam frame. The moving beam is driven by lead screws and motors on both sides, causing the slide saddle and ram to move vertically up and down. The lead screw motor end is fixed to the top of the base through a motor mount, and the lead screw nut is connected to the moving beam. The total mass of the vertical moving components is 1200 kg. To reduce wear on the shaft system and improve the service life of the shaft system components, balancing devices are added to both sides of the moving beam. In this embodiment, the rapid traverse speed is 60 m / min and the acceleration is 10 m / s², which belongs to high-speed, fast-response motion with a relatively small load value. The method to meet this counterweight requirement is pneumatic counterweight.

[0052] In this embodiment, the vertical axis travel is S = 725 mm;

[0053] Acceleration: a = 10 m / s²;

[0054] Rapid traverse speed: V1 = 60 m / min; Processing speed: V2 = 20 m / min;

[0055] Given conditions:

[0056] Load capacity: 1200kg;

[0057] Coefficient of friction: U=0.02;

[0058] Cutting force: Fa=1000 N;

[0059] Drive motor: Siemens 1FT7084-5AC75-1MH0;

[0060] Lead screw: 4020 (diameter 40, lead 20);

[0061] Based on the known conditions, the maximum axial load force can be calculated as follows:

[0062] F1=mg+f+ma=mg+umg+ma=1200x10+0.02x1200x10+1200x10=24240 N;

[0063] The corresponding torque value is:

[0064] T1=F1.L / 2π=24240x0.02 / 6.28=77.2 Nm;

[0065] The axial uniform load force is:

[0066] F2=mg+f+Fa=mg+umg+Fa=1200x10+0.02x1200x10+1000=13240 N;

[0067] The corresponding torque value is:

[0068] T2=F2.L / 2π=13240x0.02 / 6.28=42.2 Nm;

[0069] The motor has a rated torque of 16.9 Nm and a maximum torque of 81 N.

[0070] Rated speed 2000rpm, maximum speed 4000rpm;

[0071] Based on the motor parameters, the theoretical rated output torque of the dual motors is 16.9 x 2 = 33.8 Nm, which is less than the required value for T2. The solutions are either to increase the motor size or to add counterweight. This embodiment uses a pneumatic counterweight to reduce the motor load requirement. Specifically, a 100mm diameter cylinder is selected, whose speed and stroke perfectly meet the requirements of this embodiment. The counterweight force of the dual cylinders is:

[0072] Counterweight air source pressure: P=0.6Mpa, cylinder pressure, speed, and stroke meet the machine tool's operating requirements.

[0073] F0 = 2ps = 9420N;

[0074] The maximum axial load after counterweight is:

[0075] F11 = 24240 - 9420 = 14820 N;

[0076] The corresponding torque value is:

[0077] T11=F11.L / 2π=14820x0.02 / 6.28=47.2 Nm;

[0078] The axial uniform load force is:

[0079] F21 = 13240 - 9420 = 3820 N;

[0080] The corresponding torque value is:

[0081] T21=F21.L / 2π=3820x0.02 / 6.28=12.2 Nm;

[0082] The calculation results show that the maximum axial torque is 47.2 Nm, the theoretical single motor requirement is 23.6 Nm, the axial torque at constant speed is 12.2 Nm, and the theoretical single motor requirement is 6.1 Nm. The motor load meets the design requirements.

[0083] Speed ​​verification:

[0084] The motor has a maximum speed of 4000 rpm, a rated speed of 2000 rpm, a lead screw of 20 mm, and a direct drive speed ratio of 1.

[0085] Therefore, the maximum speed is 4000 x 20 x 0.001 = 80 m / min, and the rated speed is 2000 x 20 x 0.001 = 40 m / min. The speed meets the design requirements.

[0086] Calculations verified that the motor drive inertia ratio met the requirements.

[0087] The pressure regulating device includes a processing module and a control valve.

[0088] The processing module is used to obtain the position of the sliding saddle on the moving beam, and adjust the air pressure in the two cylinders according to the position using a control valve. The ratio of the air pressure in the two cylinders is inversely proportional to the ratio of the distance from the sliding saddle to both ends of the moving beam.

[0089] The pneumatic counterweight device includes two air tanks, each of which is connected to a corresponding cylinder.

[0090] The processing module is used to adjust the air pressure of the first air tank connected to the first cylinder using a control valve. .

[0091] Where W is the counterweight of the vertical moving component, L is the length of the moving beam, x is the distance from the saddle to the end of the moving beam near the first cylinder, T is the pressure area of ​​the piston, and a is the coefficient of the counterweight factor and the friction factor.

[0092] The processing module is used to adjust the air pressure of the second air tank connected to the second cylinder. .

[0093] The processing module is used to acquire the machining program data of the CNC machine tool and to obtain the movement parameters of the moving beam from the machining program data.

[0094] The gas pressure value of the gas tank in the current epoch is obtained by using the x value of the next epoch in the movement parameters. The epoch interval is generated based on the gas tank replenishment efficiency and the moving speed of the slide saddle.

[0095] Example 2

[0096] This embodiment is basically the same as Embodiment 1, except that:

[0097] The pressure regulating device includes a processing module and a control valve.

[0098] The processing module is used to obtain the position of the sliding saddle on the moving beam, and adjust the opening amount of the control valve according to the position. The ratio of the opening amounts of the two control valves is proportional to the ratio of the distances from the sliding saddle to both ends of the moving beam.

[0099] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A pneumatic counterweight device for a CNC machine tool, the CNC machine tool comprising a vertically moving component, characterized in that, The pneumatic counterweight device includes a pressure regulating device, a pressure sensor, an air tank, a cylinder, and fixing components. The pressure sensor is used to obtain the gas pressure of the gas storage tank; The air storage tank is used to provide the air source for the cylinder; The cylinder is connected between the vertically moving component and the fixed component via a cylinder bracket, and the cylinder applies an upward thrust to the vertically moving component. The pressure regulating device is used to adjust the air pressure of the air storage tank according to the counterweight of the vertically moving component; The vertical moving component includes a moving beam, a sliding saddle, and a lead screw pair. The moving beam is installed to the fixed component via the lead screw pair. The lead screw pair is connected to a lead screw motor. The lead screw motor is fixed to the fixed component via a motor mount. The moving beam moves vertically via the lead screw pair. The sliding saddle moves left and right on the moving beam. The cylinder is installed on the moving beam, and the cylinder rod of the cylinder is fixed to the bottom surface of the fixed component. The pressure regulating device includes a processing module and a control valve. The processing module is used to obtain the position of the sliding saddle on the moving beam, and adjust the air pressure in the two cylinders according to the position using a control valve. The ratio of the air pressure in the two cylinders is inversely proportional to the ratio of the distance from the sliding saddle to both ends of the moving beam. The pneumatic counterweight device includes two air tanks, each connected to a corresponding cylinder. The processing module is used to adjust the air pressure of the first air tank connected to the first cylinder using a control valve. Where W is the counterweight of the vertical moving part, L is the length of the moving beam, x is the distance from the saddle to the end of the moving beam near the first cylinder, T is the pressure area of ​​the piston, and a is the coefficient of the counterweight factor and the friction factor. The processing module is used to adjust the air pressure of the second air tank connected to the second cylinder. .

2. The pneumatic counterweight device as described in claim 1, characterized in that, The pneumatic counterweight device also includes a muffler, a one-way valve, a control pipeline, and a manual valve. The pressure regulating device, pressure sensor, and manual valve are all located on the control pipeline. One end of the control pipeline is connected to the air supply pipeline and the other end is connected to the air storage tank. The one-way valve is provided between the air supply pipeline and the control pipeline. The muffler is located at the exhaust port of the cylinder.

3. The pneumatic counterweight device as described in claim 2, characterized in that, The thrust applied by the cylinder to the vertically moving component is 50% to 80% of the counterweight of the vertically moving component; or, The pressure regulating device is used to replenish the gas tank when the vertical moving part moves upward, and to exhaust the gas tank when the vertical moving part moves downward.

4. The pneumatic counterweight device as described in claim 2, characterized in that, The exhaust port is located at the top of the cylinder, the air inlet port is located at the bottom of the cylinder, the piston of the cylinder is located between the air inlet port and the exhaust port, the piston is fixed to the cylinder rod, and the outer shells of the two cylinders are respectively fixed to both sides of the moving beam.

5. The pneumatic counterweight device as described in claim 1, characterized in that, The processing module is used to acquire the machining program data of the CNC machine tool, and to obtain the movement parameters of the moving beam from the machining program data. The x value of the next epoch in the movement parameters is used to obtain the air pressure value of the air tank in the current epoch. The epoch interval is generated according to the air tank replenishment efficiency and the moving speed of the sliding saddle.

6. A CNC machine tool, characterized in that, The CNC machine tool includes a pneumatic counterweight device as described in any one of claims 1 to 5.

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