CN114754176A - Linear motor structure - Google Patents

Abstract

The invention provides a linear motor structure, which comprises a linear motor and an adjusting mechanism, wherein the linear motor is arranged on the linear motor; the linear motor comprises a cylinder and a piston sleeved in the cylinder; the adjusting mechanism comprises a connecting pipe, a first one-way valve and an adjusting valve; the first ends of the cylinder and the piston form a back cavity, and the second ends form a compression cavity; the back cavity is communicated with the compression cavity through a connecting pipe, the connecting pipe is provided with a regulating valve and a first one-way valve, and the first one-way valve is used for limiting gas to flow only to one side with larger fluctuation pressure. According to the linear motor structure provided by the invention, the regulating valve and the first one-way valve are arranged on the connecting pipe, so that when the situation that the piston drifts or the pressure difference is formed between the compression cavity and the back cavity is detected, the gas in the back cavity and the compression cavity can only flow to one side with smaller average pressure when the first one-way valve is opened every time, the gas leaked to the back cavity through the gap between the piston and the cylinder is balanced, the pressure of the back cavity and the compression cavity is kept consistent, the drift of the piston is inhibited, and the linear motor can work efficiently and stably.

Description

Linear motor structure

Technical Field

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

Background

The linear motor is a motor structure in which a rotor is connected with a piston and moves linearly in a cylinder. Compared with a rotary motor, the linear motor adopts gas lubrication sealing between the piston and the cylinder, and is very suitable for oil-free application occasions. Meanwhile, as gas lubrication exists between the piston and the cylinder, no friction is generated between the piston and the cylinder, and the service life of the motor is very long. Linear motors have found widespread use, particularly in free piston stirling systems.

The existing linear motor can lead the gas in the compression cavity to flow to the back cavity in the operation process due to the inconsistent fluctuation pressure amplitude of the compression cavity and the back cavity, and further lead the motor piston to drift towards the compression cavity. Piston drift can cause the allowable stroke of the motor to be reduced, the electromagnetic conversion efficiency is reduced, and further the power and the efficiency of the motor are reduced.

Disclosure of Invention

The embodiment of the invention provides a linear motor structure which is used for flexibly regulating and controlling the position of a motor piston, inhibiting the piston from drifting and enabling a linear motor to 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 adjustment mechanism includes: the device comprises a connecting pipe, a first one-way valve and a regulating valve;

the piston is sleeved in the cylinder, the piston linearly reciprocates in the cylinder, the cylinder and a first end of the piston form a back cavity, and the cylinder and a second end of the piston form a compression cavity; the back cavity is communicated with the compression cavity through the connecting pipe, the adjusting valve and the first one-way valve are arranged on the connecting pipe, and the first one-way valve is used for limiting the flow of gas in the back cavity and the compression cavity only to one side with larger fluctuation pressure.

According to the linear motor structure of one embodiment of the present invention, the first check valve is used to restrict the gas in the back chamber from flowing only from the back chamber to the compression chamber.

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

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

A gap is formed between the inner stator and the outer stator, and a magnet is arranged in the gap of the rotor, so that the rotor can do linear reciprocating motion along the gap.

According to a linear motor structure of an embodiment of the present invention, the linear motor further includes: a plate spring; the leaf spring is mounted in the back cavity, the leaf spring being connected to the first end of the piston.

According to the linear motor structure of one 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 check valve for limiting the gas in the back chamber and the compression chamber to flow only to the side with smaller fluctuating pressure.

According to the linear motor structure of one embodiment of the present invention, the second check valve is used to restrict the gas in the back chamber from flowing only from the compression chamber to the back chamber.

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

the processor is electrically connected with the electromagnetic valve to control the flow of the electromagnetic valve through a control signal.

According to the linear motor structure of one embodiment of the present invention, the adjusting mechanism further includes:

A displacement sensor; the displacement sensor is electrically connected with a signal receiving end of the processor, and the displacement sensor is installed on the piston and used for acquiring a displacement signal of the piston and sending the displacement signal to the processor, so that when the displacement sensor detects that the drift of the piston is increased, the processor increases the opening degree of the regulating valve.

According to the linear motor structure of one embodiment of the present invention, the adjusting mechanism further includes:

the back cavity pressure sensor is electrically connected with the signal receiving end of the processor, is arranged in the back cavity and is used for measuring the average pressure in the back cavity;

the compression cavity pressure sensor is electrically connected with the signal receiving end of the processor, is arranged in the compression cavity and is used for measuring the average pressure in the compression cavity;

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

According to the linear motor structure provided by the invention, the adjusting mechanism is arranged, and the adjusting valve and the first one-way valve are arranged on the connecting pipe, so that when the situation that the piston drifts or the pressure difference is formed between the compression cavity and the back cavity is detected, the adjusting valve can be adjusted to ensure that gas with proper flow in the back cavity flows into the back cavity or the side with smaller average pressure in the compression cavity through the first one-way valve and the adjusting valve when the first one-way valve is opened every time, so that the gas leaked to the back cavity through the gap between the piston and the cylinder is balanced, and the average pressure of the back cavity and the compression cavity is kept consistent, thereby inhibiting the drift of the piston and enabling the linear motor to work efficiently and stably. When the working condition changes, the opening of the regulating valve can be adjusted, the gas flow can be flexibly adjusted, and the piston does not drift in all working conditions.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural view of a conventional moving magnet type linear motor;

FIG. 2 is a schematic structural diagram of a moving magnet type linear motor with a centering hole;

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

fig. 4 is a schematic structural diagram of a linear motor structure according to another embodiment of the present invention;

fig. 5 is a schematic structural diagram of a linear motor structure according to another embodiment of the present invention;

reference numerals:

1. a compression chamber; 2. an outer stator; 3. a coil; 4. a plate spring; 5. a back cavity; 6. an inner stator; 7. a mover; 8. a cylinder; 9. a piston; 10. returning to the middle hole; 11. a connecting pipe; 12. a first check valve; 13. adjusting a valve; 14. an electromagnetic valve; 15. a displacement signal of the piston; 16. a processor; 17. a solenoid valve control signal; 18. a second one-way valve.

Detailed Description

In order to make the objects, 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 drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The linear motor can be divided into a moving coil type, a moving iron type, a moving magnet type and a moving magnet type according to different driving modes. The moving magnet type linear motor will be described below as an example. As shown in fig. 1, which is a schematic structural diagram of a conventional moving magnet type linear motor, a compression chamber 1 is connected to a load end, and in the operation process of the linear motor, the fluctuating pressures of the compression chamber 1 and a back chamber 5 are inconsistent, so that in the operation process of the linear motor, gas can be accumulated to one side, and further, the piston 9 deviates from the center position, which is called piston drift.

The linear motor piston shown in fig. 1 is supported and positioned by the plate spring 4, and the amount of drift generated is relatively small due to the positioning effect of the plate spring 4. However, due to the material and structure of the plate spring 4, the service life of the linear motor is affected. And in a high-power linear motor, a greater stiffness is required to support the piston, which is difficult to satisfy by the existing plate spring 4.

Fig. 2 shows a moving magnet linear motor with a return hole, which uses gas springs and gas bearings to provide axial and radial restoring forces for the piston 9. In the operation process of the linear motor, in order to inhibit the drift of the piston 9, a centering hole 10 structure is added between the piston 9 and the air cylinder 8, the working principle of the structure is that when the piston 9 moves to a middle position, the centering hole 10 of the piston 9 is aligned with a centering groove on the air cylinder 8, the compression cavity 1 is communicated with the back cavity 5, the pressure between the compression cavity 1 and the back cavity 5 can be balanced, and the purpose of centering the piston 9 is further achieved. However, in the structure of the linear motor, since the connection time is when the speed of the piston 9 is the fastest, in actual operation and running, it is difficult to ensure that the pressure between the compression cavity 1 and the back cavity 5 is balanced, and only a certain relieving effect on the drift of the piston 9 can be achieved, and meanwhile, after the design, processing and assembly of the linear motor are completed, relevant changes cannot be performed according to running work. Leading to a very large uncertainty in its outcome.

The existing solution for the problem of piston drift of the linear motor cannot flexibly regulate and control the piston drift, is suitable for various structural sizes and working environments, and has strong uncertainty 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, and the piston always drifts from a cavity with large fluctuation pressure to a cavity with small fluctuation pressure, wherein the reason is mainly that gas is accumulated in the cavity with small fluctuation pressure due to the fact that mass flow is uniform from the cavity with large fluctuation pressure to the cavity with small fluctuation pressure, and then the average pressure in the cavity with small fluctuation pressure is larger than the cavity with large fluctuation pressure, so that the piston is pushed to move to the place with large fluctuation pressure. The direction of piston drift is from the chamber with high fluctuating pressure to the chamber with low fluctuating pressure.

Accordingly, 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 adjusting mechanism; the linear motor includes: and the cylinder 8 and the piston 9 are used for adjusting the piston drift in the linear motor through the adjusting mechanism. The adjustment mechanism includes: a connecting pipe 11, a first check valve 12 and a regulating valve 13. The piston 9 is sleeved in the cylinder 8, the piston 9 linearly reciprocates in the cylinder 8, the first ends of the cylinder 8 and the piston 9 form a back cavity 5, and the second ends of the cylinder 8 and the piston 9 form a compression cavity 1. The back cavity 5 is communicated with the compression cavity 1 through a connecting pipe 11, and a regulating valve 13 and a first one-way valve 12 are arranged on the connecting pipe 11. The first check valve 12 serves to restrict the gas in the back chamber 5 and the compression chamber 1 from flowing only to the side where the fluctuating pressure is small.

There is an average pressure in the linear motor and a fluctuating pressure added to the average pressure. It has been found that the side of the piston where the fluctuating pressure is greater is typically at a lower average pressure. The piston 9 drifts from the chamber with a small fluctuation pressure to the chamber with a large fluctuation pressure without the influence of other components. In linear motors, the piston 9 drifts toward the compression chamber 1 because the pressure fluctuation of the compression chamber 1 is generally larger. Thus, the first one-way valve 12 is normally used to restrict the flow of gas in the back chamber from the back chamber 5 to the compression chamber 1 only.

In the operation process of the linear motor, the fluctuation pressure amplitude of the compression cavity 1 is larger than the fluctuation pressure amplitude of the back cavity 5, so in a gap between the piston 9 and the cylinder 8, the flowing effect of the working medium is that gas flows from the compression cavity 1 to the back cavity 5, and further the average pressure of the back cavity 5 is higher than the average pressure of the compression cavity 1, so that the piston 9 drifts towards the compression cavity 1. Thus, the first check 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 the piston 9 is detected to drift or the pressure difference between the compression chamber 1 and the back chamber 5 is detected, the regulating valve 13 is regulated to ensure that the back chamber 5 has a proper flow of gas flowing into the compression chamber 1 through the first check valve 12 and the regulating valve 13 every time the first check valve 12 is opened, so as to balance the gas leaking to the back chamber 5 through the gap between the piston 9 and the cylinder 8. Thereby ensuring that the average pressure in the back chamber 5 and the compression chamber 1 remains the same and thereby inhibiting drift of the piston 9. When the working condition changes, the flow of gas flowing from the back cavity 5 to the compression cavity 1 can be flexibly adjusted by adjusting the opening of the adjusting valve 13, and the piston 9 is ensured not to drift in all working conditions.

According to the linear motor structure provided by the invention, the adjusting mechanism is arranged, and the adjusting valve and the first one-way valve are arranged on the connecting pipe, so that when the situation that the piston drifts or the pressure difference is formed between the compression cavity and the back cavity is detected, the adjusting valve can be adjusted to ensure that gas with proper flow in the back cavity flows into the back cavity or the side with smaller average pressure in the compression cavity through the first one-way valve and the adjusting valve when the first one-way valve is opened every time, so that the gas leaked to the back cavity through the gap between the piston and the cylinder is balanced, and the average pressure of the back cavity and the compression cavity is kept consistent, thereby inhibiting the drift of the piston and enabling the linear motor to work efficiently and stably.

As shown in fig. 3, the linear motor further includes: a stator and a mover 7. The stator and the rotor 7 are coaxially arranged, and the rotor 7 is connected with the piston 9. Wherein, the stator includes: an outer stator 2 and an inner stator 6 arranged coaxially. A gap is arranged between the inner stator 6 and the outer stator 2, and a magnet is arranged in the gap of the rotor 7 so as to make the rotor 7 do linear reciprocating motion along the gap. According to the operation requirement, 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 do linear reciprocating motion 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. A leaf spring 4 is mounted in the back chamber 5, the leaf spring 4 being connected to a first end of a piston 9. The center of the plate spring 4 is provided with a connecting hole of the piston 9, and the plate spring 4 gives a certain restoring force to the piston 9 according to the position of the piston 9 in the whole process of the linear reciprocating motion of the piston 9, so that when the piston 9 drifts, a force opposite to the drifting direction is applied to the piston 9, and the drifting of the piston 9 is reduced.

More complex operating conditions for linear motors may exist, such as when the motor compression and back cavities are at different temperatures, which may lead to more complex piston drift. For this case, the connecting pipe may be provided with a plurality of branches, and each branch of the connecting pipe may be provided with a corresponding first check valve and regulating valve, wherein at least one first check valve is arranged in a 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 check valve 18, and the second check valve 18 is installed in the direction opposite to the first check valve 12, so as to limit the gas in the back chamber 5 and the compression chamber 1 to flow only to the side with smaller fluctuating pressure. In this embodiment, the compression chamber 1 has a greater fluctuating pressure, and the second check valve 18 serves to restrict the flow of gas in the back chamber 5 from the compression chamber 1 to the back chamber 5 only.

When the piston 9 is detected to drift or the pressure difference between the compression chamber 1 and the back chamber 5 is detected, the regulating valve 13 is regulated to ensure that the back chamber 5 has a proper flow of gas flowing into the compression chamber 1 through the first check valve 12 and the regulating valve 13 when the first check valve 12 is opened each time, so as to balance the gas leaking to the back chamber 5 through the gap between the piston 9 and the cylinder 8. The second non-return valve 18 controls the flow of gas into the back chamber 5 at a suitable rate each time it is opened, according to the external operating conditions (for example temperature), balancing the effects due to other factors. The first check valve 12 and the second check valve 18 which are arranged in opposite directions are adopted, so that under complex working conditions, when the corresponding first check valve 12 or the corresponding second check valve 18 is opened each time, partial gas can be controlled to flow into the compression cavity 1, and meanwhile, partial gas can also flow into the back cavity 5. The flow direction and the flow rate of the gas in the connecting pipe 11 can be flexibly adjusted by correspondingly controlling the opening of the regulating valve 13. Therefore, different drifting conditions of the piston 9 can be adjusted correspondingly, so that the piston 9 is ensured not to drift in the operation process of the system.

It will be appreciated that for more complex situations, further branches in the connecting tube 11 may be added to accommodate more complex operating conditions.

As shown in fig. 5, the control valve 13 can also be replaced by an electrically controllable solenoid valve 14. The adjustment mechanism further 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 the control signal.

Wherein, adjustment mechanism still includes: and a displacement sensor. The displacement sensor is electrically connected with a signal receiving end of the processor 16, is installed on the piston 9, and is used for acquiring a displacement signal 15 of the piston and sending the displacement signal to the processor 16, so that when the displacement sensor detects that the drift of the piston 9 is increased, the processor increases the opening degree of the regulating valve 13.

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

Furthermore, the pressure difference between the back chamber 5 and the compression chamber 1 can be used to control the flow. A back cavity pressure sensor and a compression cavity pressure sensor are additionally arranged in the adjusting 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 a signal receiving end of the processor 16, and the compression chamber pressure sensor is installed in the compression chamber 1 and is used for measuring an average pressure in the compression chamber 1. The processor 16 adjusts the opening degree of the solenoid valve 14 by the pressures measured by the back chamber pressure sensor and the compression chamber pressure sensor, so that the gas flows to the side with the smaller average pressure through the first check valve 12.

In summary, in the linear motor structure provided by the invention, the adjusting mechanism is arranged, and the adjusting valve and the first check valve are arranged on the connecting pipe, so that when the situation that the piston drifts or the pressure difference is formed between the compression cavity and the back cavity is detected, the adjusting valve can be adjusted to ensure that gas with proper flow rate flows into the back cavity or the side with lower pressure in the compression cavity through the first check valve and the adjusting valve when the first check valve is opened every time, so as to balance the gas leaked to the back cavity through the gap between the piston and the cylinder, and further ensure that the average pressure of the back cavity and the compression cavity is kept consistent, thereby inhibiting the drift of the piston and enabling the linear motor to work efficiently and stably. When the working condition changes, the opening of the regulating valve can be adjusted, the gas flow can be flexibly adjusted, and the piston does not drift in all working conditions.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A linear motor structure, comprising:

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

the piston is sleeved in the cylinder, the piston linearly reciprocates in the cylinder, the cylinder and a first end of the piston form a back cavity, and the cylinder and a second end of the piston form a compression cavity; the back cavity is communicated with the compression cavity through the connecting pipe, the adjusting valve and the first one-way valve are arranged on the connecting pipe, and the first one-way valve is used for limiting the flow of gas in the back cavity and the compression cavity only to one side with larger fluctuation pressure.

2. A linear motor structure in accordance with claim 1, wherein said first check valve is adapted to restrict gas in said back chamber to flow only from said back chamber to said compression chamber.

3. A linear motor structure in accordance with claim 1, the linear motor further comprising: a stator and a mover; the stator and the rotor are coaxially arranged, and the rotor is connected with the piston.

4. A linear motor structure in accordance with claim 3, characterized in that the stator comprises: the outer stator and the inner stator are coaxially arranged;

a gap is formed between the inner stator and the outer stator, and a magnet is arranged in the gap of the rotor, so that the rotor can do linear reciprocating motion along the gap.

5. The linear motor structure of claim 1, further comprising: a plate spring; the leaf spring is mounted in the back cavity, the leaf spring being connected to the first end of the piston.

6. The linear motor structure according to any one of claims 1 to 5, wherein the connection pipe includes a plurality of branches, and at least one of the branches includes a second check valve for restricting gas in the back chamber and the compression chamber to flow only to a side where fluctuation pressure is small.

7. A linear motor structure according to claim 6, characterised in that the second one-way valve is adapted to restrict gas in the back chamber to flow only from the compression chamber to the back chamber.

8. A linear motor structure in accordance with claim 1, wherein said regulating valve is a solenoid valve, said regulating mechanism further comprising: a processor;

the processor is electrically connected with the electromagnetic valve to control the flow of the electromagnetic valve through a control signal.

9. The linear motor structure of claim 8, wherein the adjustment mechanism further comprises:

a displacement sensor; the displacement sensor is electrically connected with a signal receiving end of the processor, and the displacement sensor is installed on the piston and used for acquiring a displacement signal of the piston and sending the displacement signal to the processor, so that when the displacement sensor detects that the piston drift is increased, the processor increases the opening degree of the regulating valve.

10. The linear motor structure of claim 8, wherein the adjustment mechanism further comprises:

the back cavity pressure sensor is electrically connected with the signal receiving end of the processor, is arranged in the back cavity and is used for measuring the average pressure in the back cavity;

The compression cavity pressure sensor is electrically connected with the signal receiving end of the processor, is arranged in the compression cavity and is used for measuring the average pressure in the compression cavity;

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

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