CN114754176A - Linear motor structure - Google Patents

Abstract

The invention provides a linear motor structure, including a linear motor and an adjustment mechanism; the linear motor includes a cylinder and a piston sleeved in the cylinder; the adjustment mechanism includes a connecting pipe, a first one-way valve and an adjustment valve; One end forms a back cavity, and the second end forms a compression cavity; the back cavity is communicated with the compression cavity through a connecting pipe, and the connecting pipe is provided with a regulating valve and a first one-way valve, and the first one-way valve is used to limit the gas to the fluctuating pressure only The larger side flows. In the linear motor structure provided by the present invention, a regulating valve and a first one-way valve are arranged on the connecting pipe, so that when it is detected that the piston drifts or a pressure difference is formed between the compression cavity and the back cavity, the first one-way valve is guaranteed to be opened each time. , the gas in the back cavity and the compression cavity can only flow to the side with the smaller average pressure, which is used to balance the gas leaking to the back cavity through the gap between the piston and the cylinder, to ensure that the pressures of the back cavity and the compression cavity are consistent, and to suppress The drift of the piston makes the linear motor work efficiently and stably.

Description

A linear motor structure

technical field

The invention relates to the field of linear motors, in particular to a linear motor structure.

Background technique

A linear motor is a motor structure in which the mover and the piston are connected together to perform linear motion together in the cylinder. Compared with rotary motors, the linear motor uses a gas-lubricated seal between the piston and the cylinder, which is very suitable for oil-free applications. At the same time, due to the existence of gas lubrication between the piston and the cylinder, there is no friction between them, so the service life of the motor is very long. Especially in free-piston Stirling systems, linear motors are widely used.

During the operation of the existing linear motor, due to the inconsistency of the fluctuating pressure amplitudes between the compression chamber and the back chamber, the gas in the compression chamber will flow to the back chamber during operation, which in turn causes the motor piston to drift toward the compression chamber. Piston drift reduces the allowable stroke of the motor and reduces the electromagnetic conversion efficiency, which in turn reduces the power and efficiency of the motor.

SUMMARY OF THE INVENTION

The embodiment of the present invention provides a linear motor structure for flexibly regulating the position of the motor piston, suppressing the piston drift, and making the linear motor work efficiently and stably.

An embodiment of the present invention provides a linear motor structure, including:

A linear motor and an adjusting mechanism; the linear motor includes: a cylinder and a piston; the adjusting mechanism includes: a connecting pipe, a first one-way valve and an adjusting valve;

The piston is sleeved in the cylinder, the piston reciprocates linearly in the cylinder, the cylinder and the first end of the piston form a back cavity, and the cylinder and the second end of the piston form a back cavity a compression cavity; the back cavity is communicated with the compression cavity through the connecting pipe, and the connecting pipe is provided with the regulating valve and the first one-way valve, and the first one-way valve is used to limit all The gas in the back cavity and the compression cavity can only flow to the side where the fluctuating pressure is larger.

According to the linear motor structure of an embodiment of the present invention, the first one-way valve is used for restricting the gas in the back cavity to flow only from the back cavity to the compression cavity.

According to the linear motor structure of an embodiment of the present invention, the linear motor further comprises: a stator and a mover; the stator and the mover are coaxially arranged, and the mover is connected to the piston.

According to the linear motor structure of an embodiment of the present invention, the stator includes: an outer stator and an inner stator arranged coaxially;

A gap is provided between the inner stator and the outer stator, and the mover is provided with a magnet in the gap, so that the mover reciprocates linearly along the gap.

According to the linear motor structure of an embodiment of the present invention, the linear motor further comprises: a leaf spring; the leaf spring is installed in the back cavity, and the leaf spring is connected with the first end of the piston.

According to the linear motor structure of an embodiment of the present invention, the connecting pipe includes a plurality of branches, wherein at least one of the branches is provided with a second one-way valve, and the second one-way valve is used to restrict the back The gas in the cavity and the compression cavity can only flow to the side with less fluctuating pressure.

According to the linear motor structure of an embodiment of the present invention, the second one-way valve is used for restricting the gas in the back cavity to only flow from the compression cavity to the back cavity.

According to the linear motor structure of an embodiment of the present invention, the regulating valve is a solenoid valve, and the regulating mechanism further includes: a processor;

The processor is electrically connected to the solenoid valve to control the flow of the solenoid valve through a control signal.

According to the linear motor structure of an embodiment of the present invention, the adjustment mechanism further includes:

Displacement sensor; the displacement sensor is electrically connected with the signal receiving end of the processor, the displacement sensor is installed on the piston, and is used to obtain the displacement signal of the piston and send it to the processor to The processor is caused to increase the opening of the regulating valve when the displacement sensor detects an increase in the piston drift.

According to the linear motor structure of an embodiment of the present invention, the adjustment mechanism further includes:

a back cavity pressure sensor, which is electrically connected to the signal receiving end of the processor, installed in the back cavity, and used for measuring the average pressure in the back cavity;

a compression chamber pressure sensor, which is electrically connected to the signal receiving end of the processor, installed in the compression chamber, and used for measuring the average pressure in the compression chamber;

The processor adjusts the opening of the regulating valve through the pressure measured by the back cavity pressure sensor and the compression cavity pressure sensor, so that the gas flows to the side with the smaller average pressure through the first one-way valve.

In the linear motor structure provided by the present invention, by setting the adjusting mechanism, the adjusting valve and the first one-way valve are arranged on the connecting pipe, so that when it is detected that the piston drifts or a pressure difference is formed between the compression chamber and the back chamber, the adjusting valve can be adjusted by adjusting the valve. , to ensure that each time the first one-way valve is opened, there is a proper flow of gas in the back cavity through the first one-way valve and the regulating valve to flow into the back cavity or the side with the smaller average pressure in the compression cavity to balance the passage between the piston and the cylinder. The gap between them leaks to the gas in the back cavity, thereby ensuring that the average pressure of the back cavity and the compression cavity is consistent, thereby suppressing the drift of the piston and making the linear motor work efficiently and stably. Moreover, when the working conditions change, the gas flow can be flexibly adjusted by adjusting the opening degree of the regulating valve to ensure that the piston does not drift under all working conditions.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a traditional moving magnet linear motor;

Figure 2 is a schematic structural diagram of a moving magnet linear motor with a centering hole;

3 is a schematic structural diagram of a linear motor structure provided by an embodiment of the present invention;

4 is a schematic structural diagram of a linear motor structure provided by another embodiment of the present invention;

5 is a schematic structural diagram of a linear motor structure provided by another embodiment of the present invention;

Reference number:

1. Compression chamber; 2. Outer stator; 3. Coil; 4. Leaf spring; 5. Back cavity; 6. Inner stator; 7. Mover; 8. Cylinder; 9. Piston; 10. Center hole; 11. connecting pipe; 12, first check valve; 13, regulating valve; 14, solenoid valve; 15, displacement signal of piston; 16, processor; 17, solenoid valve control signal; 18, second check valve.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Linear motors can be divided into moving coil type, moving iron type, moving magnet type and moving magnet type according to different driving methods. The following is an example of a moving magnet linear motor. As shown in Figure 1, it is a schematic diagram of the structure of a traditional moving magnet linear motor. The compression chamber 1 is connected to the load end. During the operation of the linear motor, the fluctuating pressures of the compression chamber 1 and the back chamber 5 are inconsistent. During the process, the gas will accumulate to one side, which will cause the piston 9 to deviate from the center position. This phenomenon is called piston drift.

The linear motor piston shown in FIG. 1 is supported and positioned by the plate spring 4 , and due to the positioning function of the plate spring 4 , the amount of drift is relatively small. However, due to the material and structural problems of the leaf spring 4, the service life of the linear motor will be affected. And in a high-power linear motor, greater stiffness is required to support the piston, and the existing leaf spring 4 is difficult to meet this requirement.

Figure 2 shows a moving magnet linear motor with a centering hole. This linear motor uses a gas spring and a gas bearing to provide the axial restoring force and radial bearing capacity of the piston 9 . During the operation of the linear motor, in order to suppress the drift of the piston 9, a structure of a centering hole 10 is added between the piston 9 and the cylinder 8. The working principle is that when the piston 9 moves to the middle position, the centering hole 10 of the piston 9 and the cylinder 8 The upper centering grooves are aligned, and the compression chamber 1 is communicated with the back chamber 5, which can balance the pressure between the compression chamber 1 and the back chamber 5, thereby achieving the purpose of centering the piston 9. However, with such a linear motor structure, since the connection moment is when the speed of the piston 9 is the fastest, in actual operation and operation, it is difficult to ensure that the pressure between the compression chamber 1 and the back chamber 5 is balanced, and the piston 9 can only drift. It has a certain mitigation effect, and at the same time, after the design, processing and assembly of the linear motor are completed, relevant changes cannot be made according to the operation work. The uncertainty leading to its return effect is very large.

The existing solutions to the piston drift problem of linear motors cannot flexibly control the piston drift, adapt to various structural sizes and working environments, and have strong uncertainties in the process from system design to implementation. The latest research shows that the drift direction of the piston in the linear motor can be predicted according to other parameters. The piston always drifts from the cavity with large fluctuation pressure to the cavity with small fluctuation pressure, which is mainly due to the fluctuation pressure. There will be a time-averaged mass flow between a large cavity and a cavity with a small fluctuation pressure, resulting in the accumulation of gas in the cavity with a small fluctuation pressure, and then the average pressure in the cavity with a small fluctuation pressure is greater than that in the cavity with a large fluctuation pressure. , push the piston to move to the place where the fluctuating pressure is high. Therefore, the direction of piston drift is from the cavity with large fluctuation pressure to the cavity with small fluctuation pressure.

Therefore, an embodiment of the present invention provides a linear motor structure. As shown in FIG. 3 , the linear motor structure includes: a linear motor and an adjustment mechanism; the linear motor includes: a cylinder 8 and a piston 9 for adjusting the linear motor through the adjustment mechanism Mid-piston drift. The regulating mechanism includes: a connecting pipe 11 , a first one-way valve 12 and a regulating valve 13 . The piston 9 is sleeved in the cylinder 8, and the piston 9 reciprocates linearly in the cylinder 8. The cylinder 8 and the first end of the piston 9 form the back cavity 5, and the second end of the cylinder 8 and the piston 9 form the compression cavity 1. The back cavity 5 communicates with the compression cavity 1 through a connecting pipe 11 , and the connecting pipe 11 is provided with a regulating valve 13 and a first one-way valve 12 . The first one-way valve 12 is used to restrict the gas in the back chamber 5 and the compression chamber 1 to flow only to the side with less fluctuating pressure.

In linear motors there is an average pressure and a fluctuating pressure added to the average pressure. The study found that on both sides of the piston, the side with higher fluctuating pressure is usually the lower average pressure. If there is no influence of other components, the piston 9 will drift from the cavity on the side with the smaller fluctuating pressure to the cavity on the side with the larger fluctuating pressure. In a linear motor, the fluctuating pressure of the compression chamber 1 is usually larger, so the piston 9 drifts toward the compression chamber 1 . Therefore, in general, the first one-way valve 12 is used to limit the gas in the back cavity to flow only from the back cavity 5 to the compression cavity 1 .

During the operation of the linear motor, the amplitude of the fluctuating pressure in the compression chamber 1 is greater than the amplitude of the fluctuating pressure in the back chamber 5, so in the gap between the piston 9 and the cylinder 8, the effect of the working fluid flow is that the gas flows from the compression chamber 1 to the The back cavity 5 causes the average pressure of the back cavity 5 to be higher than the average pressure of the compression cavity 1 , so that the piston 9 drifts toward the compression cavity 1 . Therefore, the first one-way valve in FIG. 3 is set to open when the instantaneous pressure of the back chamber 5 is greater than the instantaneous pressure of the compression chamber 1 . When it is detected that the piston 9 drifts or a pressure difference is formed between the compression chamber 1 and the back chamber 5, the regulating valve 13 is adjusted to ensure that each time the first one-way valve 12 is opened, the back chamber 5 has a proper flow of gas to pass through the first one-way The valve 12 and the regulating valve 13 flow into the compression chamber 1 to balance the gas leaking into the back chamber 5 through the gap between the piston 9 and the cylinder 8 . Thus, it is ensured that the average pressures of the back cavity 5 and the compression cavity 1 are kept consistent, thereby suppressing the drift of the piston 9 . When the working conditions change, the flow rate of the gas flowing from the back cavity 5 to the compression cavity 1 can be flexibly adjusted by adjusting the opening degree of the regulating valve 13 to ensure that the piston 9 does not drift under all working conditions.

In the linear motor structure provided by the present invention, by setting the adjusting mechanism, the adjusting valve and the first one-way valve are arranged on the connecting pipe, so that when it is detected that the piston drifts or a pressure difference is formed between the compression chamber and the back chamber, the adjusting valve can be adjusted by adjusting the valve. , to ensure that each time the first one-way valve is opened, there is a proper flow of gas in the back cavity through the first one-way valve and the regulating valve to flow into the back cavity or the side with the smaller average pressure in the compression cavity to balance the passage between the piston and the cylinder. The gap between them leaks to the gas in the back cavity, thereby ensuring that the average pressure of the back cavity and the compression cavity is consistent, thereby suppressing the drift of the piston and making the linear motor work efficiently and stably.

As shown in FIG. 3 , the linear motor further includes: a stator and a mover 7 . The stator and the mover 7 are coaxially arranged, and the mover 7 is connected with the piston 9 . The stator includes: an outer stator 2 and an inner stator 6 arranged coaxially. A gap is provided between the inner stator 6 and the outer stator 2, and the mover 7 is provided with a magnet in the gap, so that the mover 7 reciprocates in a straight line along the gap. According to the operation requirements, correspondingly, the coil 3 can be installed on the outer stator 2 or the inner stator 6, or the coil 3 can be installed on the outer stator 2 and the inner stator 6 at the same time, so as to drive the mover 7 to reciprocate linearly along the gap.

In order to reduce the drift of the piston 9 , as shown in FIG. 3 , the linear motor further includes: a leaf spring 4 . The leaf spring 4 is installed in the back cavity 5 , and the leaf spring 4 is connected with the first end of the piston 9 . The center of the leaf spring 4 is provided with a connecting hole for the piston 9. During the entire process of the linear reciprocating motion of the piston 9, the leaf spring 4 gives a certain restoring force to the piston 9 according to the position of the piston 9, so that when the piston 9 drifts, the piston 9 is moved. 9 applies a force in the opposite direction of the drift, reducing the drift of the piston 9 .

For the more complex working conditions that may exist in the linear motor, for example, when the temperature of the motor compression chamber and the back chamber are different, this will bring about a more complex piston drift phenomenon. In view of this situation, a plurality of branches can be set on the connecting pipe, and a corresponding first one-way valve and a regulating valve can be set on the branch of each connecting pipe, wherein at least one first one-way valve is arranged in the direction of the back cavity .

In this embodiment, as shown in FIG. 4 , the connecting pipe 11 is divided into two branches, wherein at least one branch is provided with a second one-way valve 18 , the second one-way valve 18 and the first one-way valve 12 is installed in the opposite direction to limit the gas in the back cavity 5 and the compression cavity 1 to flow only to the side with less fluctuating pressure. In this embodiment, the fluctuating pressure of the compression chamber 1 is larger, and the second one-way valve 18 is used to limit the gas in the back chamber 5 to only flow from the compression chamber 1 to the back chamber 5 .

When it is detected that the piston 9 drifts or a pressure difference is formed between the compression chamber 1 and the back chamber 5, the regulating valve 13 is adjusted to ensure that the back chamber 5 has a proper flow of gas through the first check valve 12 each time the first one-way valve 12 is opened. The pressure valve 12 and the regulating valve 13 flow into the compression chamber 1 to balance the gas leaking into the back chamber 5 through the gap between the piston 9 and the cylinder 8 . The second one-way valve 18 controls an appropriate flow of gas to flow into the back cavity 5 every time the valve 13 is opened according to external working conditions (eg, temperature), balancing the influence of other factors. The first one-way valve 12 and the second one-way valve 18 arranged in opposite directions are used, so that under complicated working conditions, each time the corresponding first one-way valve 12 or the second one-way valve 18 is opened, the control part can be controlled. The gas flows into the compression chamber 1, and at the same time, part of the gas can also flow into the back chamber 5. Corresponding to the opening degree of the control valve 13 , the flow direction and flow rate of the gas in the connecting pipe 11 can be flexibly adjusted. Therefore, corresponding adjustments can be made to different drift conditions of the piston 9 to ensure that the piston 9 does not drift during the operation of the system.

It can be understood that, for more complicated situations, branches in the connecting pipe 11 can be further added to adapt to more complicated working conditions.

As shown in FIG. 5 , the regulating valve 13 can also be replaced with a solenoid valve 14 that can be electrically controlled. The adjustment mechanism also includes: a processor 16 . The processor 16 is electrically connected to the solenoid valve 14 to control the flow rate of the solenoid valve 14 through a control signal.

Wherein, the adjustment mechanism further includes: a displacement sensor. The displacement sensor is electrically connected to the signal receiving end of the processor 16, and the displacement sensor is installed on the piston 9 to obtain the displacement signal 15 of the piston and send it to the processor 16, so that when the displacement sensor detects that the piston 9 drifts increased , the processor increases the opening of the regulating valve 13 .

During the operation of the linear motor structure, the displacement signal 15 of the piston collected by the displacement sensor is used for detection and analysis, and the size of the drift generated by the piston is judged, and the size and time of the valve opening are calculated by the processor 16, and then The operating state of the solenoid valve 14 is controlled by the solenoid valve control signal 17 . The above process can achieve automatic control of the drift in the linear motor structure.

In addition, the pressure difference between the back chamber 5 and the compression chamber 1 can also be used to control the flow. A back cavity pressure sensor and a compression cavity pressure sensor are added to the adjustment mechanism. The back cavity pressure sensor is electrically connected to the signal receiving end of the processor 16 , and the back cavity pressure sensor is installed in the back cavity 5 for measuring the average pressure in the back cavity 5 . The compression chamber pressure sensor is electrically connected to the signal receiving end of the processor 16 , and the compression chamber pressure sensor is installed in the compression chamber 1 to measure the average pressure in the compression chamber 1 . The processor 16 adjusts the opening of the solenoid valve 14 through the pressure measured by the back cavity pressure sensor and the compression cavity pressure sensor, so that the gas flows to the side with the lower average pressure through the first one-way valve 12 .

To sum up, in the linear motor structure provided by the present invention, by setting the regulating mechanism, the regulating valve and the first one-way valve are arranged on the connecting pipe, so that when it is detected that the piston drifts or a pressure difference is formed between the compression chamber and the back chamber, The regulating valve can be adjusted to ensure that each time the first one-way valve is opened, there is a proper flow of gas in the back cavity through the first one-way valve and the regulating valve to flow into the back cavity or the side with the lower pressure in the compression cavity, so as to balance the passage of gas. The gap between the piston and the cylinder leaks to the gas in the back cavity, thereby ensuring that the average pressure of the back cavity and the compression cavity is consistent, thereby suppressing the drift of the piston and making the linear motor work efficiently and stably. Moreover, when the working conditions change, the gas flow can be flexibly adjusted by adjusting the opening degree of the regulating valve to ensure that the piston does not drift under all working conditions.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. a linear motor structure, is characterized in that, comprises: A linear motor and an adjusting mechanism; the linear motor includes: a cylinder and a piston; the adjusting mechanism includes: a connecting pipe, a first one-way valve and an adjusting valve; The piston is sleeved in the cylinder, the piston reciprocates linearly in the cylinder, the cylinder and the first end of the piston form a back cavity, and the cylinder and the second end of the piston form a back cavity a compression cavity; the back cavity is communicated with the compression cavity through the connecting pipe, and the connecting pipe is provided with the regulating valve and the first one-way valve, and the first one-way valve is used to limit all The gas in the back cavity and the compression cavity can only flow to the side where the fluctuating pressure is larger. 2 . The linear motor structure according to claim 1 , wherein the first one-way valve is used for restricting the gas in the back cavity to flow only from the back cavity to the compression cavity. 3 . 3 . The linear motor structure according to claim 1 , wherein the linear motor further comprises: a stator and a mover; the stator and the mover are arranged coaxially, and the mover is connected to the piston. 4 . . 4. The linear motor structure according to claim 3, wherein the stator comprises: an outer stator and an inner stator arranged coaxially; A gap is provided between the inner stator and the outer stator, and the mover is provided with a magnet in the gap, so that the mover reciprocates linearly along the gap. 5 . The linear motor structure according to claim 1 , wherein the linear motor further comprises: a leaf spring; the leaf spring is installed in the back cavity, and the first contact between the leaf spring and the piston is 5 . end connection. 6 . The linear motor structure according to claim 1 , wherein the connecting pipe comprises a plurality of branches, wherein at least one of the branches is provided with a second one-way valve, so the The second one-way valve is used for restricting the gas in the back cavity and the compression cavity to flow only to the side with less fluctuating pressure. 7 . The linear motor structure according to claim 6 , wherein the second one-way valve is used for restricting the gas in the back cavity to only flow from the compression cavity to the back cavity. 8 . 8. The linear motor structure according to claim 1, wherein the regulating valve is a solenoid valve, and the regulating mechanism further comprises: a processor; The processor is electrically connected to the solenoid valve to control the flow of the solenoid valve through a control signal. 9. The linear motor structure according to claim 8, wherein the adjustment mechanism further comprises: Displacement sensor; the displacement sensor is electrically connected with the signal receiving end of the processor, the displacement sensor is installed on the piston, and is used to obtain the displacement signal of the piston and send it to the processor to The processor is caused to increase the opening of the regulating valve when the displacement sensor detects an increase in the piston drift. 10. The linear motor structure according to claim 8, wherein the adjustment mechanism further comprises: a back cavity pressure sensor, which is electrically connected to the signal receiving end of the processor, installed in the back cavity, and used for measuring the average pressure in the back cavity; a compression chamber pressure sensor, which is electrically connected to the signal receiving end of the processor, installed in the compression chamber, and used for measuring the average pressure in the compression chamber; The processor adjusts the opening of the regulating valve through the pressure measured by the back cavity pressure sensor and the compression cavity pressure sensor, so that the gas flows to the side with the smaller average pressure through the first one-way valve.

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