CN210396818U

CN210396818U - Air inlet and exhaust mechanical control system of piston type expansion machine

Info

Publication number: CN210396818U
Application number: CN201920612512.1U
Authority: CN
Inventors: 马一太; 王派; 李昱翰; 詹浩淼; 李梓瑄; 刘雪涛; 李敏霞
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2019-04-30
Filing date: 2019-04-30
Publication date: 2020-04-24
Anticipated expiration: 2029-04-30

Abstract

The utility model belongs to the technical field of refrigeration/heat pump, a piston expander's air intake and exhaust mechanical control system is disclosed. The mechanical control system comprises an air inlet control module and an air outlet control module; the two cams are respectively provided with a cam fixed on a crankshaft of the expansion machine, and the cams rotate along with the crankshaft to push the corresponding tappet rods to move up and down in the valve body. Each tappet drives a corresponding valve rod in the valve body to rotate around the axis of the tappet through the meshing motion of the rack and the gear; the valve rods are respectively provided with valve holes matched with the internal/external air inlet/outlet pipes in the valve body, and communicated air flow channels can be formed when the valve rods rotate to a certain direction, so that air inlet and outlet parameters are controlled. The utility model discloses an advance to exhaust machinery control system simple structure, control are accurate, be difficult for receiving the environmental disturbance, are applicable to the multi-cylinder piston expansion-compression all-in-one of each piston connecting rod sharing bent axle, have realized the good synchronization of expansion-compressor advance, exhaust process and the inflation that corresponds, each stage of compression process.

Description

Air inlet and exhaust mechanical control system of piston type expansion machine

Technical Field

The utility model belongs to the technical field of refrigeration/heat pump, concretely relates to piston expander's advance, exhaust mechanical type control system.

Background

In the development process of refrigeration technology, the updating and upgrading of refrigerants are always very important technological promotion means. Refrigerant development is also accompanied by ozone destruction and greenhouse effect problems. Environmental issues are especially acute at the fourth meeting in the montreal protocol in 1992 and at the 19 th meeting in the member country in the montreal protocol in 2007, and the call for the phase out of refrigerants with high GWP (global warming potential) and high ODP (ozone attenuation potential) is very high.

Refrigerants are also indispensable in other industrial production and daily life. These demands have led to the development of refrigerants. In recent years, fourth generation refrigerants typified by natural media and near-natural media have been rapidly developed.

The fourth generation refrigerant, such as near natural working fluids (HFOs type working fluids), has high synthesis and manufacturing costs. This means that the production process will bring high energy consumption and high emission, and the secondary greenhouse effect will come with it. And CO₂As a natural working medium, the refrigerant has many advantages, such as environmental friendliness (ODP is 0, and GWP is 1), safety, no toxicity, nonflammability, good heat transfer performance, good fluidity, large volume refrigerating capacity, compatibility with common lubricants and structural materials, low price, low maintenance cost and the like. CO 2₂Therefore, the refrigerant becomes a high-quality refrigerant working medium.

Due to CO₂If applied to a refrigeration/heat pump cycle, the system can be circulated transcritically (the suction pressure of the compressor is lower than the critical pressure, and the discharge pressure is higher than the critical pressure). However, CO₂There are also some technical barriers to heat pump systems, the most major problems being: the throttling loss is large due to the high pressure in the refrigeration system. CO 2₂The efficiency of the transcritical cycle is generally lower than that of the subcritical cycle of the common working medium (the suction pressure and the exhaust pressure of the compressor are both lower than the critical pressure). In order to reduce the throttling loss of the transcritical cycle, a device is needed to replace the throttling valve, so that the throttling efficiency of the system is improved.

The expander is a machine which obtains energy by utilizing the principle that mechanical work is output outwards when compressed gas is expanded and depressurized to reduce the temperature and pressure of the gas, and is widely applied to low-temperature devices. Among various expansion machines, the piston type expansion machine has greater development potential due to the characteristics of simple structure, good sealing performance, good reliability and the like. However, the expander has different air intake and exhaust characteristics from the compressor, and the exhaust process should be long and the air intake process should be rapid to reduce the throttling loss and prolong the expansion process. However, the air intake and exhaust processes of the expander and the operation period of the piston of the expander should be kept in close conformity, otherwise, the expansion ratio will be reduced, thereby affecting the energy saving effect of the expander. The traditional valve and the active periodic control system have the leakage problem when being closed due to structural gaps, and the electromagnetic control system is adopted, so that the electromagnetic interference caused by alternating current equipment such as a motor can be caused, and the control accuracy is influenced. Therefore, an efficient and controllable mechanical air inlet and exhaust control system is designed to ensure the consistency of the air inlet and exhaust periods of the expander and the operation period of the piston, and for CO₂The development, research and utilization of the expansion machine are of great value.

Disclosure of Invention

The utility model aims at advancing in the current expander technique, the inconsistent problem of exhaust cycle and inflation process to lead to leaking and clearance loss, thereby influence system operating efficiency's problem, provide a piston expander advance, exhaust mechanical control system, with the throttle loss that reduces the expander and optimize the inflation process.

In order to achieve the purpose, the utility model adopts the following technical proposal:

a mechanical control system for air inlet and exhaust of a piston type expansion machine is used for controlling the opening and closing of an air inlet valve and an air exhaust valve of an expansion cylinder in the piston type expansion machine, wherein the expansion cylinder is connected to a crankshaft of a prime mover through a connecting rod, and the crankshaft is an output shaft of the prime mover; the mechanical control system for air intake and exhaust of the piston type expansion machine comprises a valve body embedded in a cylinder cover of the expansion cylinder; the valve body is provided with an air inlet control cavity structure and an air outlet control cavity structure which are arranged in parallel, the air inlet control cavity structure and the air outlet control cavity structure are respectively communicated with the inside of the expansion cylinder and are respectively communicated with the outside through air passages on two side walls parallel to the rotation axis of the crankshaft on the valve body; (ii) a The air inlet control mechanism is characterized by also comprising an air inlet control mechanism, wherein one end of the air inlet control mechanism is connected in the air inlet control cavity structure in a sliding manner, and the other end of the air inlet control mechanism is connected at the terminal end of the crankshaft; the exhaust control mechanism is characterized by further comprising an exhaust control mechanism, one end of the exhaust control mechanism is connected in the exhaust control cavity structure in a sliding mode, and the other end of the exhaust control mechanism is connected at the end of the crankshaft and arranged in a staggered mode with the air inlet control mechanism.

The air inlet control cavity structure comprises a deep hole-shaped outer air inlet channel which is distributed on one side wall of the valve body and communicated with the outside; an inner air inlet channel which is distributed at one end of the bottom surface of the valve body embedded in the expansion cylinder and is communicated with the outer air inlet channel; a deep-hole-shaped air inlet valve rod cavity is arranged in the valve body at a position which is perpendicular to a plane formed by the axes of the outer air inlet channel and the inner air inlet channel and orthogonally penetrates through the inner air inlet channel; a deep-hole-shaped air inlet tappet cavity is distributed on the bottom surface of the other end of the valve body, which is far away from the expansion cylinder; the air inlet tappet cavity penetrates through the air inlet valve rod cavity in a staggered manner and is provided with an air inlet tappet rack groove; the exhaust control cavity structure comprises deep-hole-shaped outer exhaust passages which are distributed on the opposite side walls of the valve body and communicated with the outside; the inner air exhaust channel is distributed at one end of the bottom surface of the valve body embedded in the expansion cylinder and is communicated with the outer air exhaust channel; a deep-hole-shaped exhaust valve rod cavity is arranged in the valve body at a position which is perpendicular to a plane formed by the axes of the outer exhaust passage and the inner exhaust passage and orthogonally penetrates through the inner exhaust passage; a deep-hole-shaped exhaust tappet cavity is distributed on the bottom surface of the other end of the valve body, which is far away from the expansion cylinder; the exhaust tappet cavity is crossed through the exhaust valve rod cavity in a staggered mode.

The air inlet control mechanism comprises an air inlet valve rod in sliding fit with the air inlet valve rod cavity; the air inlet valve rod is provided with an air inlet valve hole which is matched with the outer air inlet channel and the inner air inlet channel and is communicated with the outer air inlet channel and the inner air inlet channel, and an air inlet pipe is formed when the air inlet valve rod is communicated with the outer air inlet channel and the inner air inlet channel; an air inlet valve rod gear is arranged on the air inlet valve rod at the circumference which is staggered and orthogonal with the air inlet tappet cavity; an air inlet tappet rack vertically meshed with the air inlet valve rod gear is positioned on the air inlet tappet; the air inlet tappet is in sliding fit with the air inlet tappet cavity, and an air inlet spring is arranged between the top end of the air inlet tappet and the blind end of the air inlet tappet cavity; the upper half part is provided with the air inlet tappet rack at the part crossed with the air inlet valve rod in a staggered way, and the lower end of the air inlet tappet rack is connected with an air inlet cam arranged at the terminal end of the crankshaft through an air inlet jacking mechanism; the exhaust control mechanism comprises an exhaust valve rod in sliding fit with the exhaust valve rod cavity, and a through exhaust valve hole matched with the outer exhaust passage and the inner exhaust passage is distributed on the exhaust valve rod at an exhaust plane to form an exhaust pipe when the exhaust valve rod is communicated with the outer exhaust passage and the inner exhaust passage; an exhaust valve rod gear is arranged on the exhaust valve rod at the circumference which is staggered and orthogonal with the exhaust tappet cavity; an exhaust tappet rack vertically meshed with the exhaust valve rod gear is positioned on the exhaust tappet; exhaust tappet with exhaust tappet chamber sliding fit, the top with between the exhaust tappet chamber blind hole cecum, laid exhaust spring, first one with the crossing part of exhaust valve rod dislocation has been seted up exhaust tappet rack, the end is connected with via exhaust climbing mechanism and installs the exhaust cam of bent axle terminal department.

The air inlet jacking mechanism and the air exhaust jacking mechanism are roller mechanisms which are respectively an air inlet roller and an air exhaust roller; the air inlet roller and the air outlet roller are respectively fixed on the air inlet tappet and the air outlet tappet through rolling bearings and are respectively contacted with the air inlet cam and the air outlet cam on rolling tangent planes.

The part of the air inlet tappet outside the valve body is sleeved in an air inlet tappet guide pipe which is fixedly arranged at the inner shell of the expansion machine and used for limiting the air inlet tappet to move up and down; and the part of the exhaust tappet outside the valve body is sleeved in an exhaust tappet guide pipe which is fixedly arranged at the inner shell of the expansion machine and used for limiting the exhaust tappet to move up and down.

The air inlet tappet and the air outlet tappet are respectively positioned on two sides of a plane formed by the central line of the expansion cylinder and the rotating shaft axis of the crankshaft in the same angle in the working plane.

The angle is less than or equal to 10 degrees.

The air inlet spring is in a natural state when the air inlet jacking mechanism is in contact with the base circle surface of the air inlet cam (2); the exhaust spring is in a natural state when the exhaust jacking mechanism is in contact with the base circle surface of the exhaust cam.

Effective rack lengths of the intake and exhaust tappet racks are at least equal to the lift of the corresponding intake and exhaust cams, respectively; the effective number of teeth of the intake tappet rack and the exhaust tappet rack is at least equal to the number of teeth rotated by the intake valve rod gear and the exhaust valve rod gear corresponding to the respective rotation of the intake valve rod and the exhaust valve rod by 90 degrees.

A plurality of air inlet lubricating oil channels which are communicated with the air inlet tappet cavity from the outside are distributed in the valve body, and at least one air inlet lubricating oil channel is communicated with the air inlet tappet cavity; and a plurality of exhaust lubricating oil channels which are communicated with the exhaust tappet cavity from the outside are distributed in the valve body, and at least one exhaust lubricating oil channel is communicated with the exhaust tappet cavity.

The same on the valve body the axis of interior intake duct interior exhaust way, for the axis symmetry of expansion cylinder, and be located same with on the perpendicular plane of crankshaft rotation axle center.

The utility model has the advantages that:

(1) the cycle of the air inlet and exhaust process is synchronous with the running cycle of the piston type expansion machine, so that the consistency of the running process of the expansion machine is improved, and the overall running efficiency of the system is improved.

(2) The valve hole structure of the valve rod is adopted, so that the problem of working medium leakage generated when the air inlet/outlet valve is closed is effectively solved.

(3) And a compact mechanical control structure is adopted, so that the interference caused by electromagnetic or mechanical vibration in the environment can be effectively avoided.

Drawings

FIG. 1 is a schematic structural front view of an air intake and exhaust mechanical control system of the present invention; FIG. 2 is a left side schematic view of FIG. 1; FIG. 3 is a schematic sectional view taken along line A-A of FIG. 1; FIG. 4 is a schematic sectional view taken along line B-B of FIG. 1; FIG. 5 is a schematic cross-sectional view taken along line C-C of FIG. 1.

FIG. 6 is a schematic diagram of the right and front views of the engagement between the intake tappet and the intake valve rod of the present invention; FIG. 7 is a schematic diagram of the right and front views of the engagement between the exhaust tappet and the exhaust valve stem of the present invention; FIG. 8 is a schematic cross-sectional view A-A of the structure of FIG. 1 with a valve cover on the valve body.

Wherein: 1-crankshaft 2-intake cam 3-intake tappet 3A-intake tappet cavity 4-intake jacking mechanism 5-intake spring 6-intake valve rod 6A-intake valve rod cavity 7-intake pipe 7A-external intake channel 7B-intake valve hole 7C-internal intake channel 8-intake tappet guide 9-intake lubricating oil hole 10-intake tappet rack 11-intake valve rod gear 12-exhaust cam 13-exhaust tappet 13A-exhaust tappet cavity 14-exhaust jacking mechanism 15-exhaust spring 16-exhaust valve rod 16A-exhaust valve rod cavity 17-exhaust pipe 17A-external exhaust air channel 17B-exhaust valve hole 17C-internal exhaust air channel 18-exhaust tappet guide 19-exhaust lubricating oil hole 20 Tappet rack 21-exhaust valve rod gear 22-valve body 23-expansion cylinder 24-prime mover 25-connecting rod

Detailed Description

For further understanding the contents, features and effects of the present invention, the following embodiments will explain the technical solution of the present invention in detail:

an air inlet and exhaust mechanical control system of a piston type expansion machine is used for controlling the opening and closing of an air inlet valve and an exhaust valve of an expansion cylinder 23 in the piston type expansion machine, the expansion cylinder 23 is connected to a crankshaft 1 of a prime mover 24 through a connecting rod 25, and the crankshaft 1 is an output shaft of the prime mover 24; the mechanical control system for air intake and exhaust of the piston type expansion engine comprises a valve body 22 embedded in a cylinder cover of an expansion cylinder 23; the valve body 22 is provided with an air inlet control cavity structure and an air outlet control cavity structure which are arranged in parallel, are respectively communicated with the inside of the expansion cylinder 23 and are respectively communicated with the outside through air passages on two side walls which are parallel to the rotation axis of the crankshaft 1 on the valve body 22; (ii) a The air inlet control mechanism is characterized by also comprising an air inlet control mechanism, wherein one end of the air inlet control mechanism is connected in the air inlet control cavity structure in a sliding manner, and the other end of the air inlet control mechanism is connected at the terminal end of the crankshaft 1; the exhaust control mechanism is connected with the end of the crankshaft 1 at one end and is arranged in a staggered manner with the air inlet control mechanism;

the air inlet control cavity structure comprises a deep hole-shaped outer air inlet channel 7A which is distributed on one side wall of the valve body 22 and communicated with the outside; an inner air inlet channel 7C which is arranged at one end of the bottom surface of the valve body 22 embedded in the expansion cylinder 23 and is communicated with the outer air inlet channel 7A; a deep-hole-shaped air inlet valve rod cavity 6A is arranged in the valve body 22, is perpendicular to a plane formed by the axes of the outer air inlet channel 7A and the inner air inlet channel 7C, and orthogonally penetrates through the inner air inlet channel 7C; a deep-hole-shaped air inlet tappet cavity 3A is distributed on the bottom surface of the other end of the valve body 22 away from the expansion cylinder 23; the air inlet tappet cavity 3A penetrates through the air inlet valve stem cavity 6A in a staggered manner and is provided with an air inlet tappet rack groove; the exhaust control cavity structure comprises outer exhaust passages 17A which are arranged on the opposite side walls of the valve body 22 and are in a deep hole shape and communicated with the outside; an inner air exhaust duct 17C which is arranged at one end of the bottom surface of the valve body 22 embedded in the expansion cylinder 23 and is communicated with the outer air exhaust duct 17A; a deep-hole-shaped exhaust valve rod cavity 16A is arranged in the valve body 22, is vertical to the exhaust plane and passes through the axis of the inner exhaust passage 17C; a deep-hole-shaped exhaust tappet cavity 13A is distributed on the bottom surface of the other end of the valve body 22 away from the expansion cylinder 23; the exhaust tappet cavity 13A is offset through the exhaust valve stem cavity 16A and is slotted with an exhaust tappet rack slot.

The air inlet control mechanism comprises an air inlet valve rod 6 in sliding fit with an air inlet valve rod cavity 6A; the air inlet valve rod 6 is provided with a through air inlet valve hole 7B matched with the outer air inlet channel 7A and the inner air inlet channel 7C at the air inlet plane, and an air inlet pipe 7 is formed when the air inlet valve rod is communicated with the air inlet channel 7A and the inner air inlet channel 7C; an air inlet valve rod gear 11 is arranged on the air inlet valve rod 6 at the circumference which is staggered and orthogonal with the air inlet tappet cavity 3A; an air inlet tappet rack 10 vertically meshed with the air inlet valve rod gear 11 is positioned on the air inlet tappet 3; the air inlet tappet 3 is in sliding fit with the air inlet tappet cavity 3A, and an air inlet spring 5 is arranged between the top end of the air inlet tappet 3A and the blind hole blind end of the air inlet tappet cavity 3A; the upper half part and the air inlet valve rod 6 are crossed in a staggered way, an air inlet tappet rack 10 is arranged, and the lower end of the air inlet tappet rack is connected with an air inlet cam 2 arranged at the terminal end of the crankshaft 1 through an air inlet jacking mechanism 4; the exhaust control mechanism comprises an exhaust valve rod 16 in sliding fit with an exhaust valve rod cavity 16A, and an exhaust valve hole 17B which is matched with the outer exhaust passage 17A and the inner exhaust passage 17C and is communicated with the exhaust valve rod 16 is distributed on an exhaust plane to form an exhaust pipe 17; an exhaust valve rod gear 21 is arranged on the exhaust valve rod 16 at the circumference which is staggered and orthogonal with the exhaust tappet cavity 13A; an exhaust tappet rack 20 vertically meshed with an exhaust valve rod gear 21 is positioned on the exhaust tappet 13; exhaust tappet 13 and exhaust tappet chamber 13A sliding fit, the top with between the exhaust tappet chamber 13A blind hole cecum, laid exhaust spring 15, the crossing part of upper half and exhaust valve rod 16 dislocation has seted up exhaust tappet rack 20, and the end is connected with the exhaust cam 12 of installing in bent axle 1 terminal end department via exhaust climbing mechanism 14.

The air inlet jacking mechanism 4 and the air outlet jacking mechanism 14 are roller mechanisms which are respectively an air inlet roller and an air outlet roller; the intake roller and the exhaust roller are fixed to the intake tappet 3 and the exhaust tappet 13 through rolling bearings, respectively, and are in contact with the intake cam 2 and the exhaust cam 12 in rolling tangent planes, respectively.

The part of the air inlet tappet 3 outside the valve body 22 is sleeved in an air inlet tappet guide pipe 8 which is fixedly arranged at an inner shell of the expansion machine and used for limiting the air inlet tappet 3 to move up and down; the part of the exhaust tappet 13 outside the valve body 22 is sleeved in an exhaust tappet guide 18 which is fixedly arranged at the inner shell of the expansion machine and used for limiting the upward and downward movement of the exhaust tappet 13.

Intake lifter 3 and exhaust lifter 13 are located on both sides of a plane formed by the center line of expansion cylinder 23 and the rotation axis of crankshaft 1 at the same angle in their respective working planes.

The angle is less than or equal to 10 degrees.

The air inlet spring 5 is in a natural state when the air inlet jacking mechanism 4 is in contact with the base circular surface of the air inlet cam 2; the exhaust spring 15 is in a natural state when the exhaust lift mechanism 14 is in contact with the base circular surface of the exhaust cam 12.

The effective rack lengths of the intake and

exhaust tappet racks

10, 20 are at least equal to the lift of the corresponding intake and

exhaust cams

2, 12, respectively; the effective number of teeth of intake tappet rack 10 and exhaust tappet rack 20 is at least equal to the number of teeth rotated by intake valve stem gear 11 and exhaust valve stem gear 21 corresponding to the respective rotations of intake valve stem 6 and exhaust valve stem 16 by 90 °.

A plurality of air inlet lubricating oil channels 9 leading to the air inlet tappet cavity 6A from the outside are distributed in the valve body 22, and at least one air inlet lubricating oil channel 9 leads to the air inlet tappet cavity 3A; several exhaust lubricating oil channels 19 leading from outside to the exhaust tappet cavity 16A are arranged in the valve body 22, and at least one exhaust lubricating oil channel 19 leading to the exhaust tappet cavity 13A.

The axes of the inner air inlet channel 7C and the inner air exhaust channel 17C on the same valve body 22 are symmetrical relative to the axis of the expansion cylinder 23 and are positioned on the same plane vertical to the rotating axis of the crankshaft 1.

The following detailed description of specific embodiments will be made with reference to the accompanying drawings 1 to 8:

a piston type expansion machine, the crankshaft 1 of which is driven by a prime mover 24 (in this example, an electric motor); a valve body 22 is fixed on the top cover of the expansion cylinder; the outer side of a crankshaft 1 of the expansion machine is extended and is additionally provided with an air inlet cam 2 and an exhaust cam 12; the valve body 22 is provided with an air inlet tappet cavity 3A and an air outlet tappet cavity 13A, and is respectively provided with a partially inserted air inlet tappet 3 and an air outlet tappet 13; the air inlet tappet 3 and the air outlet tappet 13 are respectively contacted with the air inlet cam 2 and the air outlet cam 12 through an air inlet jacking mechanism 4 and an air outlet jacking mechanism 14 (in the example, rollers connected through rolling bearings are selected); the movement of the air inlet tappet 3 and the air outlet tappet 13 is restricted by respectively adopting an air inlet tappet guide pipe 8 and an air outlet tappet guide pipe 18 which are fixed on the expander body; an air inlet valve rod cavity 6A and an air outlet valve rod cavity 16A which are respectively vertical to the air inlet tappet cavity 3A and the air outlet tappet cavity 13A in a staggered manner and are partially communicated are arranged in the valve body 22, and an air inlet valve rod 6 and an air outlet valve rod 16 are respectively arranged in the air inlet tappet cavity and the air outlet tappet cavity; intake tappet 3, intake tappet rack 10 and exhaust tappet rack 20 on exhaust tappet 13, respectively engage with intake valve rod gear 11 and exhaust valve rod gear 21 fixed on intake valve rod 6 and exhaust valve rod 16. The parts above the air inlet tappet 3 and the air outlet tappet 13 are respectively connected to the tops of an air inlet tappet cavity 3A and an air outlet tappet cavity 13A through an air inlet spring 5 and an air outlet spring 15, and the

springs

5 and 15 both adopt compression springs; the intake valve rod 6 and the exhaust valve rod 16 are constrained in the intake valve rod chamber 6A and the exhaust valve rod chamber 16A and can only rotate around the axes thereof.

When the intake cam 2 rotates along with the crankshaft 1 to an intake angle, namely the intake cam 2 is at a high position, the intake tappet 3 is pushed by the intake jacking mechanism 4 to rise to the high position, the intake spring 5 is compressed at the moment, and the intake tappet rack 10 pushes the intake valve rod gear 11 to roll the intake valve rod 6 to a specific angle, and the intake valve hole 7B rotates to be communicated with the matched outer intake channel 7A and the inner intake channel 7C, so that the intake pipe 7 communicating the inside and the outside of the expansion cylinder 23 is formed, and the intake process is started. When the air inlet cam 2 rotates along with the crankshaft 1 to a non-air inlet angle, namely the air inlet cam 2 is at a low position, the air inlet spring 5 recovers from a compression state, so that the air inlet tappet 3 is pushed to return to the low position, the air inlet valve rod 6 rolls to an original angle, the air inlet valve hole 7B rotates to an angle which is not communicated with the matched outer air inlet channel 7A and the matched inner air inlet channel 7C, the air inlet pipe 7 which is communicated with the inside and the outside of the expansion cylinder 23 is cut off, and the air inlet process is closed. The exhaust process and the intake process are the same.

Good meshing performance is needed among the intake tappet 3, the intake tappet rack 10 and the exhaust tappet rack 20 of the exhaust tappet 13 and the corresponding intake valve rod gear 11 and the exhaust valve rod gear 21, so that the intake valve rod 6 and the exhaust valve rod 16 can rotate along with the intake cam 2 and the exhaust cam 12 to accurately steer. The effective tooth lengths of the air inlet tappet rack 10 and the air outlet tappet rack 20 are respectively not less than the lift ranges of the corresponding air inlet cam 2 and the air outlet cam 12, so that a certain allowance is reserved for the stability of a meshing system; the numbers of teeth of the intake tappet rack 10 and the exhaust tappet rack 20 corresponding to the lifts of the intake cam 2 and the exhaust cam 12 should be equal to the numbers of rotating teeth corresponding to the respective rotation of 90 degrees of the intake valve rod gear 11 and the exhaust valve rod gear 21, so that the intake valve hole 7B and the exhaust valve hole 17B can rotate quickly, the opening and closing processes of the intake valve and the exhaust valve are more accurate and sensitive, the leakage phenomenon possibly occurring when the valve is closed is reduced, and the influence of the motion deviation of the system after mechanical vibration on the stability of the system is weakened. Accordingly, the parameters of tappet intake tappet rack 10, exhaust tappet rack 20, and intake valve stem gear 11, exhaust valve stem gear 21, as well as the radii of intake valve stem 6, exhaust valve stem 16, require precise calculations in actual design applications.

Because the working medium pressure is large before expansion, the air inlet process needs to be relatively quick to prevent the working medium from entering too much high-pressure working medium to cause the working medium to be incapable of being fully expanded, and therefore the angle of the lift range part of the air inlet cam 2 is smaller than the angle occupied by the base circle part of the air inlet cam. Because the pressure of the expanded working medium is small, the exhaust process needs to be realized passively, so that the angle of the lift part of the exhaust cam 12 is obviously longer than that of the lift part of the intake cam 2 and occupies about half of the total angle of the cams. Meanwhile, the volume of the expanded working medium is increased, a larger space is needed for quick outflow, and the diameter of each part of the exhaust pipe 17 is larger than that of the air inlet pipe 7 to reduce exhaust resistance and avoid extra throttling loss.

The operation frequency of the expander crankshaft 1 is usually very high, so that the intake valve rod 6 and the exhaust valve rod 16 are required to operate quickly, cannot be locked due to oil shortage during movement, and have high sealing performance. High precision of engagement and sealing between the intake tappet 3, the exhaust tappet 13 and the intake valve stem 6, the exhaust valve stem 16, and the valve body 22 is required, and the friction surfaces of the shafts, bores, racks, and gears are supplemented with lubricating oil. The lower parts of the intake tappet 3 and the exhaust tappet 13 are matched with the intake cam 2 and the exhaust cam 12 through rollers (an intake jacking mechanism 4 and an exhaust jacking mechanism 14), and good lubrication is also required. The valve body 22 has at least two lubricating oil passages (an air inlet lubricating oil passage 9 and an air outlet lubricating oil passage 19) which respectively provide lubricating oil for the air inlet tappet 3 and the air outlet tappet 13, and the lubricating oil flows along the air inlet tappet 3 and the air outlet tappet 13 and can provide lubricating and sealing effects for the air inlet valve rod 6, the air outlet valve rod 16, tappet rollers (an air inlet jacking mechanism 4 and an air outlet jacking mechanism 14) and other parts.

Alternatively, the valve body 22 may be designed as a split structure formed by connecting the valve body 22 and the valve cover 25, as shown in fig. 8. In this case, the valve cover 25 is fixed to the valve body 22 in the direction opposite to the direction of the expansion cylinder 23, the intake tappet cavity 3A and the exhaust tappet cavity 13A in the valve body 22 are designed as through holes, the intake spring 5 and the exhaust spring 15 are placed into the intake tappet cavity 3A and the exhaust tappet cavity 13A before the valve cover 25 is fixedly mounted, and other structural designs and connections are consistent with the technical scheme without the valve cover 25. This arrangement will make the parts of the apparatus easier to manufacture and easy to troubleshoot, but may increase the risk of leakage of the high pressure gas working fluid.

The above description is of the preferred embodiments of the present invention, but the present invention is not limited to the above-described embodiments. The preferred embodiments described above are illustrative only and not limiting. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto and changes may be made without departing from the scope of the invention in its broader aspects. All of which fall within the scope of the present invention.

Claims

1. An air inlet and exhaust mechanical control system of a piston type expansion machine is used for controlling the opening and closing of an air inlet valve and an exhaust valve of an expansion cylinder (23) in the piston type expansion machine, the expansion cylinder (23) is connected to a crankshaft (1) of an external prime mover (24) through a connecting rod (25), and the crankshaft (1) is an output shaft of the prime mover (24);

the method is characterized in that:

comprises a valve body (22) embedded in a cylinder cover of the expansion cylinder (23); the valve body (22) is provided with an air inlet control cavity structure and an air outlet control cavity structure which are arranged in parallel, are respectively communicated with the inside of the expansion cylinder (23), and are respectively communicated with the outside through air passages on two side walls which are parallel to the rotation axis of the crankshaft (1) on the valve body (22);

the air inlet control mechanism is characterized by also comprising an air inlet control mechanism, wherein one end of the air inlet control mechanism is movably connected into the air inlet control cavity structure, and the other end of the air inlet control mechanism is contacted with the air inlet cam (2); the air inlet cam (2) is arranged near the terminal of the crankshaft (1);

the exhaust control mechanism is characterized by also comprising an exhaust control mechanism, one end of the exhaust control mechanism is movably connected in the exhaust control cavity structure, and the other end of the exhaust control mechanism is contacted with an exhaust cam (12); the exhaust cam (12) is connected to the vicinity of the terminal of the crankshaft (1) and is arranged in a staggered manner with the intake cam (2).

2. The mechanical control system for the intake and exhaust of the piston expander as claimed in claim 1,

the method is characterized in that:

the air inlet control cavity structure comprises a deep hole-shaped outer air inlet channel (7A) which is arranged on one side wall of the valve body (22) and communicated with the outside, and an inner air inlet channel (7C) which is arranged at one end of the bottom surface of the valve body (22) embedded into the expansion cylinder (23) and vertically communicated with the outer air inlet channel (7A); a deep-hole-shaped air inlet valve rod cavity (6A) is arranged in the valve body (22) at a position which is perpendicular to a plane formed by the axes of the outer air inlet channel (7A) and the inner air inlet channel (7C) and orthogonally penetrates through the inner air inlet channel (7C); a deep-hole-shaped air inlet tappet cavity (3A) is formed in the bottom surface of the other end, far away from the expansion cylinder (23), of the valve body (22), and the air inlet tappet cavity (3A) penetrates through the air inlet valve rod cavity (6A) in a staggered mode;

the exhaust control cavity structure comprises a deep hole-shaped outer exhaust air passage (17A) which is arranged on the side wall of the valve body (22) opposite to the outer air inlet channel (7A) and communicated with the outside, and an inner exhaust air passage (17C) which is arranged at one end of the bottom surface of the valve body (22) embedded in the expansion cylinder (23) and vertically communicated with the outer exhaust air passage (17A); a deep-hole-shaped exhaust valve rod cavity (16A) is arranged in the valve body (22) at a position which is perpendicular to a plane formed by the axes of the outer exhaust passage (17A) and the inner exhaust passage (17C) and orthogonally penetrates through the inner exhaust passage (17C); a deep-hole-shaped exhaust tappet cavity (13A) is distributed on the bottom surface of the other end, far away from the expansion cylinder (23), of the valve body (22); the exhaust tappet cavity (13A) penetrates through the exhaust valve rod cavity (16A) in a staggered mode.

3. The mechanical control system for the intake and exhaust of the piston expander as claimed in claim 2,

the method is characterized in that:

the air inlet control mechanism comprises an air inlet valve rod (6) which is in rotary fit with the air inlet valve rod cavity (6A); the air inlet valve rod (6) is provided with an air inlet valve hole (7B) which is matched with the outer air inlet channel (7A) and the inner air inlet channel (7C) and is communicated with the outer air inlet channel and the inner air inlet channel, and an air inlet air path is formed when the air inlet valve rod and the inner air inlet channel are communicated; an air inlet valve rod gear (11) is arranged on the air inlet valve rod (6) at the circumference which is staggered and orthogonal with the air inlet tappet cavity (3A); the air inlet tappet (3) is in sliding fit with the air inlet tappet cavity (3A), an air inlet spring (5) is arranged between the top end of the air inlet tappet (3A) and the top of the air inlet tappet cavity, an air inlet tappet rack (10) meshed with the air inlet valve rod gear (11) is arranged at the staggered and intersected part of the upper half part and the air inlet valve rod (6), and the lower end of the air inlet tappet rack is in contact with the air inlet cam (2) through an air inlet jacking mechanism (4);

the exhaust control mechanism comprises an exhaust valve rod (16) in sliding fit with the exhaust valve rod cavity (16A), and an exhaust valve hole (17B) which is matched with the outer exhaust passage (17A) and the inner exhaust passage (17C) and is communicated with the outer exhaust passage (17A) and the inner exhaust passage (17C) is distributed on the exhaust valve rod (16) at an exhaust plane to form an exhaust gas path; an exhaust valve rod gear (21) is arranged on the exhaust valve rod (16) at the periphery which is staggered and orthogonal with the exhaust tappet cavity (13A); exhaust tappet chamber (13A) with exhaust tappet chamber (13A) sliding fit, at the top with exhaust spring (15) have been laid between exhaust tappet chamber (13A) top, first half with the crossing part of exhaust valve pole (16) dislocation seted up with exhaust valve pole gear (21) engaged with exhaust tappet rack (20) contact via exhaust climbing mechanism (14) in the lower extreme and reach exhaust cam (12).

4. The mechanical control system for the intake and exhaust of the piston expander according to claim 3, wherein: the air inlet jacking mechanism (4) and the air exhaust jacking mechanism (14) are roller mechanisms and are correspondingly an air inlet roller and an air exhaust roller; the air inlet roller and the air outlet roller are fixed on the air inlet tappet (3) and the air outlet tappet (13) through corresponding rolling bearings and are in contact with the corresponding air inlet cam (2) and the corresponding air outlet cam (12) on rolling tangent planes.

5. The mechanical control system for the intake and exhaust of the piston expander according to claim 3, wherein: the part of the air inlet tappet (3) outside the valve body (22) is sleeved in an air inlet tappet guide pipe (8) which is fixedly arranged at the inner shell of the expansion machine and used for limiting the air inlet tappet (3) to move up and down; the part of the exhaust tappet (13) outside the valve body (22) is sleeved in an exhaust tappet guide pipe (18) which is fixedly arranged at the inner shell of the expansion machine and used for limiting the exhaust tappet (13) to move up and down.

6. The mechanical control system for the intake and exhaust of the piston expander according to claim 3, wherein: the intake tappet (3) and the exhaust tappet (13) are respectively positioned on two sides of a plane formed by the central line of the connecting rod (25) and the rotating shaft central line of the crankshaft (1) at the same angle in respective working planes.

7. The mechanical control system for the intake and exhaust of the piston expander according to claim 6, wherein: the angle is less than or equal to 10 degrees.

8. The mechanical control system for the intake and exhaust of the piston expander according to claim 3, wherein: the air inlet spring (5) is in a natural state when the air inlet jacking mechanism (4) is in contact with the base circle surface of the air inlet cam (2); the exhaust spring (15) is in a natural state when the exhaust jacking mechanism (14) is in contact with the base circle surface of the exhaust cam (12).

9. The mechanical control system for the intake and exhaust of the piston expander according to claim 3, wherein: the effective rack lengths of the air inlet tappet rack (10) and the air outlet tappet rack (20) are respectively at least equal to the corresponding lift ranges of the air inlet cam (2) and the air outlet cam (12), and the effective tooth number is at least equal to the tooth number of the air inlet valve rod gear (11) and the air outlet valve rod gear (21) which are respectively corresponding to the air inlet valve rod (6) and the air outlet valve rod (16) rotating by 90 degrees.

10. The mechanical control system for the intake and exhaust of the piston expander as claimed in claim 9, wherein: a plurality of air inlet lubricating oil channels (9) leading to the air inlet tappet cavity (6A) from the outside are distributed in the valve body (22), and at least one air inlet lubricating oil channel (9) leads to the air inlet tappet cavity (3A); a plurality of exhaust lubricating oil channels (19) leading to the exhaust tappet cavity (16A) from the outside are distributed in the valve body (22), and at least one exhaust lubricating oil channel (19) leads to the exhaust tappet cavity (13A).

11. The mechanical control system for the intake and exhaust of the piston expander as claimed in claim 9, wherein the axes of the internal intake duct (7C) and the internal exhaust duct (17C) on the same valve body (22) are symmetrical with respect to the axis of the expansion cylinder (23) and are located on the same plane perpendicular to the rotation axis of the crankshaft (1).