CN103527554A - Friction-free constant-force-output air-floating device with volume compensation function - Google Patents

Abstract

The invention provides a frictionless constant force output air flotation device with volume compensation, which includes an output cylinder, a compensation cylinder, and an air storage tank; the output cylinder includes a cylinder barrel and a long piston, and the compensation cylinder includes a connecting rod piston, a compensation The cylinder and the compensation cylinder are respectively set in the air storage tank. The air storage chamber is formed between the air storage tank, the cylinder and the compensation cylinder. The air storage chamber is divided into an upper air storage chamber and a lower air storage chamber which are independent of each other. The air storage chamber, the inner cavity of the cylinder and the inner cavity of the compensation cylinder communicate with the lower air storage chamber; the long piston is set in the cylinder and there is a very small gap between the cylinder and the connecting rod piston. In the compensation cylinder; the frictionless constant force output air flotation device with volume compensation also includes a ball screw, a motor, a laser displacement sensor, and a reflector; the invention adds a compensation cylinder and an air storage tank, through volume compensation and Air pressure control can realize precise, high-speed constant force output.

Description

A Frictionless Constant Force Output Air Floatation Device with Volume Compensation

technical field

The invention relates to a constant force output device.

Background technique

According to different application environments and application requirements, there are various structures and implementation methods for constant force output. Dynamic constant force output refers to loading a constant force value on a dynamically moving target workpiece.

Hanging the target workpiece through weights is the simplest and most commonly used method of applying constant force. Since the mass of the weight is constant, the force acting on the target workpiece remains unchanged, but when the target workpiece is accelerating or decelerating, the weight The weight will generate an additional force acting on the target workpiece due to the influence of its own inertial force, and the greater the mass of the weight, the greater the effect, so this method is only suitable for low-speed or uniform-speed movement of the target workpiece. Torque motors, hydraulic cylinders, etc. are also often used in the field of constant force output. For example, the patent application number 201120495617.7 "Hydraulic device with constant force output" has announced a hydraulic device that outputs precise force values through a PLC controller, an electromagnetic proportional valve, and a pressure sensor. However, the pressure sensor in this device is installed on the hydraulic device. At the output, the pressure sensor is in motion and therefore affects the accuracy of the measured value. The air-floating frictionless cylinder is widely used in the realization of ultra-precise constant force output control and micro-pressure action control; there is no friction between the piston and the cylinder through gas lubrication, so the force acting on the piston is related to the cross-sectional area of the piston and The air pressure in the cylinder is related to the size of the air pressure in the cylinder; the patent application No. 201110072339.9 "Frictionless Cylinder with Air Bearing" discloses an air-floating frictionless cylinder. In addition, the response speed of the gas is slow, and the volume change caused by the piston movement in the cylinder will cause the air pressure transient and cause the fluctuation of the output constant force. Therefore, the air-floating frictionless cylinder is generally used to realize the action output, constant pressure The control is more difficult, and it is difficult to ensure the constant value of the output force.

Contents of the invention

Aiming at the problems in the existing constant force output device that the output force value is difficult to keep constant, the sensor measurement is not accurate enough, and the constant force output accuracy is not high, the present invention provides a frictionless constant force device with volume compensation, accurate output force value and good stability. Output air flotation device.

The technical solution adopted by the present invention to solve its technical problems is:

A frictionless constant force output air flotation device with volume compensation, comprising an output cylinder, a compensation cylinder and an air storage tank. The output cylinder includes a cylinder barrel and a long piston, and the compensation cylinder includes a connecting rod piston and a compensation cylinder.

The cylinder and the compensation tube are set in the gas storage tank respectively, and the gas storage chamber is formed between the gas storage tank, the cylinder and the compensation tube, and the gas storage cavity is divided into an upper gas storage chamber and a lower gas storage chamber which are independent Cavity, the inner cavity of the cylinder and the inner cavity of the compensation cylinder communicate with the lower air storage chamber; the long piston is set in the cylinder with a very small gap between the cylinder and the connecting rod piston is set in the compensation cylinder Inside; the frictionless constant force output air flotation device with volume compensation also includes a ball screw, a motor, a laser displacement sensor, and a reflector; the ball screw is installed outside the air storage tank, and the connecting rod piston The connecting seat is connected with the ball screw, the motor is connected with the ball screw, the reflector is installed on the long piston, and the laser displacement sensor is fixed outside the gas tank and opposite to the reflector.

The air storage tank is provided with a first air inlet and a second air inlet, the first air inlet communicates with the first air storage chamber, and the second air inlet communicates with the second air storage chamber. The first air inlet and the second air inlet are respectively connected to the proportional valve through air pipes.

The center of the long piston is provided with an air intake through hole and an air discharge through hole, the air intake through hole and the air discharge through hole are separated by a sealing plug, and the air intake through hole communicates with the lower air storage chamber.

First radial throttle holes are evenly distributed along the circumference of the long piston, the first radial throttle holes communicate with the air intake through hole, and there are at least two sets of first radial throttle holes along the axial direction ; Second radial orifices are evenly distributed along the circumference of the cylinder, and the second radial orifices communicate with the upper air storage cavity. Throttle plugs are installed in the first radial throttle hole and the second radial throttle hole.

The first pressure relief groove is provided on the long piston, and the first pressure relief groove includes a first groove on the outer cylindrical surface of the long piston, radial blind holes uniformly distributed along the circumference in the first groove, and A first axial hole that communicates with the blind hole; one end of the first axial hole communicates with the air discharge through hole through the second groove in the air discharge through hole, and the other end of the first axial hole passes through a blocking block Sealing; the first groove has at least two groups and is located on both sides of the first radial throttling hole; the first pressure relief groove and the first radial throttling hole are isolated from each other.

The cylinder is provided with a second pressure relief groove, the second pressure relief groove includes a third groove on the inner cylindrical surface of the cylinder, a second axial hole communicating with the third groove, the second The other end of the axial hole communicates with the atmosphere outside the gas storage tank; the third groove is located below the second radial orifice, and the second pressure relief groove is isolated from the second radial orifice .

The design concept of the present invention is: since the cross-sectional area of the piston is constant, as long as the pressure of the gas entering the inner cavity of the cylinder is kept constant, the output force value can be kept constant. However, the movement of the piston causes the volume of the cavity to change, and there is a certain hysteresis in the gas compensation, which causes a transient change in the air pressure and leads to fluctuations in the output force. Therefore, the present invention increases the compensation cylinder and the air storage tank, the first air storage chamber and the second air storage chamber are formed between the air storage tank, the cylinder barrel, and the compensation cylinder, and the intake chamber of the output cylinder and the intake chamber of the compensation cylinder Connected through the second air storage chamber, the displacement of the long piston in the output cylinder is measured by the laser displacement sensor, and then the corresponding displacement of the connecting rod piston in the compensation cylinder is controlled by the ball screw to ensure that the internal volume of the second air storage chamber remains unchanged. Pressure fluctuations due to long piston movements are avoided. Through volume compensation and air pressure control, precise, high-speed constant force output can be realized.

The first air storage chamber supplies air to the second radial orifice on the cylinder to ensure a stable air film between the cylinder and the long piston; the long piston is a cylinder, and the end outside the cylinder is the output end. There is a first radial orifice at one end of the cylinder, and the gas in the cylinder intake chamber forms an air film between the piston and the cylinder through the first radial orifice; two air films provide support for the piston And lubrication, simple structure and air supply method, good bearing capacity.

There are two air inlets on the air storage tank for separate air supply, and the air pressure is controlled by a proportional valve, so that the two air storage chambers do not affect each other, which improves the accuracy and stability of the constant force output.

There are pressure relief grooves near the radial orifice. The pressure relief grooves communicate with the external normal pressure. On the one hand, it prevents the high-pressure gas in the cylinder from entering the air-floating gap and affecting the air film, and plays a sealing role. A normal pressure zone is formed inside to promote the formation of gas film.

The invention has the advantages of simple structure, high precision and good stability.

Description of drawings

Figure 1 is a schematic diagram of a frictionless constant force output air flotation device with volume compensation

Figure 2 is a schematic diagram of the long piston

Figure 3 is a schematic diagram of the cylinder

Detailed ways

1 to 3 , a frictionless constant force output air flotation device with volume compensation includes an output cylinder, a compensation cylinder, and an air storage tank 8 . The output cylinder includes a cylinder barrel 4 and a long piston 2 , and the compensation cylinder includes a connecting rod piston 18 and a compensation cylinder 17 .

The cylinder 4 and the compensating tube 17 are set in the gas storage tank 8 respectively, and the gas storage chamber is formed between the gas storage tank 8, the cylinder 4 and the compensation tube 17, and the gas storage cavity is divided into an upper gas storage chamber 7 and a lower storage chamber which are independent of each other. The air cavity 9, the inner cavity of the cylinder 4 and the inner cavity of the compensation cylinder 17 communicate with the lower air storage chamber 9; the long piston 2 is set in the cylinder 4 and there is a very small gap between the cylinder and the connecting rod piston 18. In the compensation cylinder 17; a frictionless constant force output air flotation device with volume compensation also includes a ball screw 20, a motor 21, a laser displacement sensor 15, and a reflector 16; the ball screw 20 is installed outside the gas storage tank 8, The connecting rod piston 18 is connected to the ball screw 20 through the connecting seat 19, the motor 21 is connected to the ball screw 20, the reflector 16 is installed on the long piston 2, and the laser displacement sensor 15 is fixed outside the gas tank 8 and at the position of the reflector 16 relatively.

The air storage tank 8 is provided with a first air inlet 5 and a second air inlet 10, the first air inlet 5 communicates with the first air storage chamber 7, and the second air inlet 10 communicates with the second air storage chamber 9 . The first air inlet 5 and the second air inlet 10 are respectively connected to the proportional valve 6 through air pipes.

The center of the long piston 2 has an air intake through hole 24 and an air discharge through hole 3, and the air intake through hole 24 and the air discharge through hole 3 are isolated by a sealing plug 12, and the air intake through hole 24 communicates with the lower air storage chamber 9.

On the long piston 2, first radial throttle holes 11 are evenly distributed along the circumference, and the first radial throttle holes 11 communicate with the air intake through hole 24. There are two groups of first radial throttle holes 11 along the axial direction; Second radial throttling holes 14 are evenly distributed on the cylinder 4 along the circumference, and the second radial throttling holes 14 communicate with the upper air storage cavity 7 . Throttle plugs are installed in the first radial throttle hole 11 and the second radial throttle hole 14 .

The long piston 2 is provided with a first pressure relief groove, and the first pressure relief groove includes a first groove 23 on the outer cylindrical surface of the long piston 2, radial blind holes 25 uniformly distributed along the circumference in the first groove 23, and The first axial hole 26 that the radial blind hole 25 communicates; one end of the first axial hole 26 communicates with the air discharge through hole 3 through the second groove 13 in the air discharge through hole 3, and the other end of the first axial hole 26 One end is sealed by a blocking block 22; there are at least two groups of first grooves 23 located on both sides of the first radial orifice 11; the first pressure relief groove and the first radial orifice 11 are isolated from each other.

The cylinder 4 is provided with a second pressure relief groove, the second pressure relief groove includes a third groove 27 on the inner cylindrical surface of the cylinder 4, a second axial hole 28 communicating with the third groove 27, and the second shaft The other end of the hole 28 communicates with the atmosphere outside the gas storage tank 8; the third groove 27 is located below the second radial orifice 14, and the second pressure relief groove and the second radial orifice 14 are isolated from each other .

Claims (1)

1. A frictionless constant force output air flotation device with volume compensation, characterized in that: it includes an output cylinder, a compensation cylinder, and an air storage tank; the output cylinder includes a cylinder barrel and a long piston; the compensation cylinder includes a connecting rod Piston, compensation cylinder; The cylinder and the compensation tube are set in the gas storage tank respectively, and the gas storage chamber is formed between the gas storage tank, the cylinder and the compensation tube, and the gas storage cavity is divided into an upper gas storage chamber and a lower gas storage chamber which are independent Cavity, the inner cavity of the cylinder and the inner cavity of the compensation cylinder communicate with the lower air storage chamber; the long piston is set in the cylinder with a very small gap between the cylinder and the connecting rod piston is set in the compensation cylinder Inside; the frictionless constant force output air flotation device with volume compensation also includes a ball screw, a motor, a laser displacement sensor, and a reflector; the ball screw is installed outside the air storage tank, and the connecting rod piston The connecting seat is connected to the ball screw, the motor is connected to the ball screw, the reflector is installed on the long piston, and the laser displacement sensor is fixed outside the gas tank and opposite to the reflector; The air storage tank is provided with a first air inlet and a second air inlet, the first air inlet communicates with the first air storage chamber, and the second air inlet communicates with the second air storage chamber; The first air inlet and the second air inlet are respectively connected to the proportional valve through the air pipe; The center of the long piston is provided with an air intake through hole and an air discharge through hole, the air intake through hole and the air discharge through hole are separated by a sealing plug, and the air intake through hole communicates with the lower air storage chamber; First radial throttle holes are evenly distributed along the circumference of the long piston, the first radial throttle holes communicate with the air intake through hole, and there are at least two sets of first radial throttle holes along the axial direction ; Second radial orifices are evenly distributed along the circumference of the cylinder, and the second radial orifices communicate with the upper air storage cavity. Throttle plugs are installed in the first radial orifice and the second radial orifice; The first pressure relief groove is provided on the long piston, and the first pressure relief groove includes a first groove on the outer cylindrical surface of the long piston, radial blind holes uniformly distributed along the circumference in the first groove, and A first axial hole that communicates with the blind hole; one end of the first axial hole communicates with the air discharge through hole through the second groove in the air discharge through hole, and the other end of the first axial hole passes through a blocking block Sealing; the first groove has at least two groups and is located on both sides of the first radial orifice; the first pressure relief groove and the first radial orifice are isolated from each other; The cylinder is provided with a second pressure relief groove, the second pressure relief groove includes a third groove on the inner cylindrical surface of the cylinder, a second axial hole communicating with the third groove, the second The other end of the axial hole communicates with the atmosphere outside the gas storage tank; the third groove is located below the second radial orifice, and the second pressure relief groove is isolated from the second radial orifice .

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