CN107906805B

CN107906805B - Expansion valve

Info

Publication number: CN107906805B
Application number: CN201711368839.0A
Authority: CN
Inventors: 金耿; 阮义兵
Original assignee: Zhejiang Zeshun Refrigeration Technology Co ltd
Current assignee: Zhejiang Zeshun Refrigeration Technology Co ltd
Priority date: 2017-12-18
Filing date: 2017-12-18
Publication date: 2023-07-28
Anticipated expiration: 2037-12-18
Also published as: CN107906805A

Abstract

The invention provides an expansion valve, and belongs to the technical field of valves. The expansion valve solves the problem of low control precision of the existing expansion valve. The expansion valve comprises a valve core I and a valve core II, wherein the valve core I is provided with a through throttling hole, the two end surfaces of the valve core are provided with plug connectors, the outer wall of each plug connector is provided with at least two cylindrical surfaces with different diameters, the at least two cylindrical surfaces are sequentially arranged along the plug connection direction according to the decreasing diameter, the part of the throttling hole, which extends inwards from the orifice to the axial length of each plug connector, is a plug connection section, the throttling hole is provided with a throttling wall, which extends inwards from the orifice, the throttling wall is in a straight cylinder shape, the length of the throttling wall is smaller than or equal to that of the plugging section, and when the plug connector is inserted into the throttling hole, at least one cylindrical surface can be opposite to the throttling wall and form a throttling channel. The expansion valve has higher flow control precision.

Description

Expansion valve

Technical Field

The invention belongs to the technical field of valves, and relates to an expansion valve.

Background

The four parts of the compressor, the condenser, the expansion valve and the evaporator form a refrigerating system together, the expansion valve is an important part in the refrigerating system and is generally arranged between the condenser and the evaporator, the expansion valve can enable gas evaporated by the evaporator to be pressurized and liquefied to high-temperature high-pressure liquid refrigerant through the compressor, the liquid refrigerant is throttled to be low-temperature low-pressure vaporous liquid refrigerant through a throttle orifice of the liquid refrigerant, then the refrigerant absorbs heat in the evaporator to achieve a refrigerating effect, the expansion valve controls valve flow through overheat change at the tail end of the evaporator, and liquid impact caused by insufficient utilization of the evaporator area due to insufficient flow and incomplete vaporization of the refrigerant due to insufficient evaporator area due to excessive flow is prevented from being sucked into the compressor.

As disclosed in chinese patent application number 201210419218.1, an expansion valve is disclosed, which comprises a housing having an inlet end and an outlet end, a straight tubular valve body having an inner cavity is fixed in the housing, an inlet and an outlet communicating the inner cavity with the housing are provided on a side wall of the valve body, a spacer for separating the inlet from the outlet is provided between the housing and the valve body, a first valve core and a second valve core which can slide along the inner cavity and are matched with each other are provided in the inner cavity, a retainer ring is fixed in the middle of the inner cavity between the first valve core and the second valve core, spring assemblies for making the first valve core and the second valve core have a tendency to move toward the retainer ring are respectively provided at two ends of the inner cavity, a damping structure capable of buffering the first valve core and the second valve core is provided between the first valve core and the second valve core, the damping structure comprises a front cylinder, a front throttling cone, a rear cylinder, a rear throttling cone, a front guide post and the second valve core are sequentially provided on a rear throttling cone, a rear cylindrical hole, a hollow groove, a front throttling cone and a front cylindrical hole are sequentially provided on the valve core, the front throttling cone and the front cylindrical hole are sequentially matched with the first valve core head, the front throttling cone, the rear throttling cone and the rear throttling cone are mutually matched with the front throttling cone, the front cone and the front throttling cone are mutually opened, the front cone and the front throttling cone are respectively, the front throttling cone and the front cone are opened, and the front cone and the front throttling cone are simultaneously, respectively, and the front throttle valve opening and the front valve opening respectively, and the two air valve opening and the two. 1. Intermediate heating and intermediate refrigeration; 2. rated heating and rated cooling; 3. maximum cooling and maximum heating; 4. cooling the ground pattern; 5. heating at high temperature; the refrigerant flow rates corresponding to the five stages are also divided into five stages, and it is apparent that the above-described expansion valve is difficult to achieve multi-stage accurate adjustment of the refrigerant flow rates.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides an expansion valve for solving the problem of low flow control precision of the existing expansion valve.

The aim of the invention can be achieved by the following technical scheme: the expansion valve comprises a valve core I and a columnar valve core II, wherein the valve core I is provided with a through throttling hole, the expansion valve is characterized in that the two end faces of the valve core II are provided with columnar plug connectors which can be inserted into the throttling hole, the outer diameter of each plug connector is smaller than that of the valve core II, the outer wall of each plug connector is provided with at least two cylindrical surfaces with different diameters, the cylindrical surfaces are orderly arranged in a decreasing manner along the plug connection direction, the part of the throttling hole, which extends inwards from the orifice to the axial length of the plug connector, is a plug connection section, the throttling hole is provided with a throttling wall, which extends inwards from the orifice, the throttling wall is in a straight cylinder shape, the length of the throttling wall is smaller than or equal to the length of the plug connection section, the inner diameter of the throttling wall is smaller than that of other positions of the plug connection section, and when the plug connector is inserted into the throttling hole, at least one cylindrical surface can be opposite to the throttling wall and form a throttling channel.

When the throughput of the refrigerant is smaller or the refrigerant does not pass through, the valve core I is propped against the valve core II, the plug connector is completely inserted into the orifice, the refrigerant can push the valve core I or the valve core II when the refrigerant needs to pass through the expansion valve, so that the valve core II and the valve core I do relative far away movement, when the throttle wall is opposite to a cylindrical surface with larger diameter and forms a throttle channel, the passing cross section area of the throttle channel is smaller, the first-stage accurate control of the flow of the refrigerant is realized, when the cylindrical surface moves out of the orifice and is staggered with the throttle wall along with the relative movement of the valve core I and the valve core II, the flow of the refrigerant can not be controlled, the next cylindrical surface is opposite to the throttle wall to form a throttle channel, the diameter of the cylindrical surface is smaller than that of the last cylindrical surface, therefore, the passing cross section area of the throttle channel is enlarged, the second-stage accurate adjustment of the flow of the refrigerant is realized, when the valve core I and the valve core II move relatively, the cylindrical surface moves out of the throttle hole to be staggered with the throttle wall, the flow of the refrigerant is not controlled, then the next cylindrical surface and the throttle wall are opposite to form a throttle channel, the diameter of the cylindrical surface is smaller than that of the previous cylindrical surface, so that the passing sectional area of the throttle channel is enlarged again, the third-stage accurate adjustment of the flow of the refrigerant is realized, in the resetting movement process of the valve core I and the valve core II, the passing sectional area of the throttle channel is gradually reduced in three stages, the buffer effect is better, wherein the throttle channel is formed by the cylindrical surface and the straight cylindrical throttle wall relatively, the passing sectional area of the throttle channel is not changed in the process of the opposite to the throttle wall to be gradually staggered, the flow of the refrigerant is small, namely the expansion valve can realize the accurate control of the flow of at least three stages of the refrigerant, and the flow rate change is small in the flow rate control process of each stage, and the flow rate control precision is high.

In the expansion valve, the length of the throttling wall is greater than or equal to the length of any cylindrical surface. The length of the throttling wall and the cylindrical surface can determine the maximum length of the throttling channel, the increase of the length of the throttling channel can increase the resistance to the refrigerant passing, the resistance can control the flow, and meanwhile, the cylindrical surface can form the throttling channel only when the cylindrical surface is opposite to the throttling wall, so that the throttling wall is greater than or equal to the length of the cylindrical surface, and the accurate control of the cylindrical surface on the flow can be fully exerted.

In the expansion valve, three cylindrical surfaces are provided, two conical surfaces are further arranged on the outer wall of the plug connector, the two conical surfaces are positioned at one end of the plug connector, which is close to the two end surfaces of the valve core, one end of the conical surface with smaller diameter is connected with the cylindrical surface with the largest diameter, and one end with larger diameter is connected with one end of the other conical surface with smaller diameter. The conical surface and the throttling wall can form a throttling channel when being opposite, the passing sectional area of the throttling channel is smaller, namely, the throttling wall can form five-stage throttling channels with different passing sectional areas with three cylindrical surfaces and two conical surfaces, and one end with larger diameter of the conical surface faces to two end surfaces of the valve core, so that the passing sectional area of the throttling channel formed by the conical surface and the throttling wall becomes larger gradually along with the relative moving of the valve core and the valve core, thereby playing a role of buffering, namely, the larger conical surface can realize primary flow buffering, the smaller conical surface can realize secondary flow buffering, and therefore, the expansion valve can sequentially form primary flow buffering, secondary flow buffering, primary precise adjustment, secondary precise adjustment and tertiary precise adjustment in the opening process, thereby realizing five-stage flow control of refrigerant and improving control precision.

In the expansion valve, the taper of the conical surface close to the two end surfaces of the valve core is smaller than that of the other conical surface. The conical surface with smaller taper is used for controlling the flow in the initial stage of the relative moving away of the valve core I and the valve core II, so that the flow change is small, a good buffering effect is achieved, then the conical surface with larger taper is used for controlling the flow, the flow change is relatively large, the flow change can be buffered, the transition can be carried out on the adjacent cylindrical surfaces, and the accurate control of the flow is achieved.

In the expansion valve, a conical transition surface is arranged between two adjacent cylindrical surfaces, one end of the transition surface with a larger diameter is connected with the cylindrical surface with a larger diameter, and one end of the transition surface with a smaller diameter is connected with the cylindrical surface with a smaller diameter. The flow controlled by different cylindrical surfaces is different, so that the flow can jump in the transition process, and the transition surface can buffer the flow change, so that the flow is steadily increased or reduced.

In the expansion valve, the first valve core is internally provided with a stepped surface which is arranged around the orifice of the orifice, the two end surfaces of the valve core or the stepped surface of the first valve core are provided with buffer grooves which are arranged around the plug, and the buffer grooves are communicated with the orifice passage. The existing valve core I and the valve core II are not provided with buffer grooves, the step surface of the valve core I is propped against the end surface of the valve core II, at the moment that the step surface of the valve core I is separated from the end surface of the valve core II, the refrigerant acts on the whole end surface of the valve core II, namely, the acting area suddenly becomes large, so that the stress change of the valve core II is large, and further, the relative movement speed change of the valve core I and the valve core II is large, so that the flow change is large.

In the expansion valve, one end of the first valve core is provided with the buffer cavity for the insertion of the second valve core, the step surface is positioned between the buffer cavity and the orifice, the orifice is communicated with one end port of the valve body, the buffer cavity is communicated with the other end port of the valve body, the end surface of the second valve core is also provided with a plurality of liquid passing grooves in the circumferential direction, one end buffer grooves of the liquid passing grooves are communicated, and the other end of the liquid passing grooves are communicated with the buffer cavity. When the valve core I abuts against the valve core II, the liquid passing groove can still enable the buffer groove to be communicated with the buffer cavity, namely the expansion valve still allows the refrigerant with smaller flow to pass through, so that the valve core I and the valve core II cannot move relatively when the flow of the refrigerant is smaller, the opening and closing times of the valve core I and the valve core II are reduced, abrasion between the valve core I and the valve core II is reduced, and the service life is prolonged.

In the expansion valve, the length direction of the liquid passing groove is arranged along the radial direction of the two end faces of the valve core, three liquid passing grooves are formed, and the three liquid passing grooves are uniformly distributed in the circumferential direction. The liquid passing grooves are circumferentially and uniformly distributed, so that the acting force on the valve core II is uniform when a small flow of refrigerant passes through, and the valve core I and the valve core II are kept stable.

In the expansion valve, the orifice edge of the orifice hole is provided with an arc chamfer in the circumferential direction. The arc chamfer can reduce the resistance when the refrigerant flows, plays the cushioning effect, and is convenient for radially accurate control to the refrigerant.

The expansion valve comprises a valve core I and a columnar valve core II, wherein the valve core I is provided with a through orifice, the expansion valve is characterized in that the two end faces of the valve core II are provided with columnar plug connectors which can be inserted into the orifice, the outer diameter of each plug connector is smaller than that of the valve core II, the inner wall of the orifice is internally provided with at least three straight barrel surfaces with different diameters, the at least three straight barrel surfaces are orderly arranged from the orifice hole inwards according to the decreasing diameter, the outer wall of each plug connector is provided with a throttling wall which is columnar and can be opposite to the straight barrel surface at the innermost side of the orifice, the diameter of each throttling wall is smaller than that of the straight barrel surface with the smallest radial dimension, and when the plug connectors are inserted into the orifice, the throttling wall can be opposite to the straight barrel surfaces and form a throttling channel.

When the throughput of the refrigerant is smaller or the refrigerant does not pass through, the valve core I is abutted against the valve core II, the plug connector is completely inserted into the throttling hole, the refrigerant can push the valve core I or the valve core II to move relatively far away from the valve core I when the refrigerant needs to pass through the expansion valve, when the throttling wall is opposite to the straight cylinder surface with smaller diameter to form a throttling channel, the passing cross section area of the throttling channel is smaller, the first-stage accurate control of the flow rate of the refrigerant is realized, when the valve core I and the valve core II move relatively, the straight cylinder surface is staggered with the throttling wall, the flow rate of the refrigerant is not controlled, the next straight cylinder surface and the throttling wall form a throttling channel relatively, the diameter of the straight cylinder surface is larger than that of the last straight cylinder surface, so the passing cross section area of the throttling channel is larger, the second-stage accurate adjustment of the flow rate of the refrigerant is realized, when the valve core I and the valve core II continue to move relatively, the straight cylinder surface and the throttling wall are staggered, the flow of the refrigerant is not controlled, then the next straight cylinder surface and the throttling wall are opposite to form a throttling channel, the diameter of the straight cylinder surface is larger than that of the last straight cylinder surface, so that the passing sectional area of the throttling channel is enlarged again, the third-stage accurate adjustment of the flow of the refrigerant is realized, in the resetting movement process of the valve core I and the valve core II, the passing sectional area of the throttling channel is gradually reduced in three stages, the buffer effect is better, wherein the throttling channel is formed by the opposite of the straight cylinder surface and the cylindrical throttling wall, the passing sectional area of the throttling channel is not changed in the process of the opposite of the straight cylinder surface and the throttling wall to the gradual staggering, the flow change of the refrigerant is small, namely the expansion valve can realize the accurate control of the flow of at least three stages of the refrigerant, and the flow rate change is small in the flow rate control process of each stage, and the flow rate control precision is high.

In the expansion valve, the outer wall of the plug is circumferentially provided with a protruding throttling part, the outer circumferential wall of the throttling part is the throttling wall, and the distance from one end of the throttling wall, which is close to the two end surfaces of the valve core, to the two end surfaces of the valve core is smaller than or equal to the sum of the lengths of the straight cylinder surfaces. The throttling wall is formed by the throttling part, so that the diameter of the throttling wall is larger than that of the plug, and the throttling wall can form a throttling channel with the straight cylinder surface at the moment of relative movement of the valve core and the valve core, thereby accurately controlling the flow of the refrigerant.

In the expansion valve, a protruding throttling part is circumferentially arranged on the outer wall of the plug, the outer circumferential wall of the throttling part is the throttling wall, and one end of the throttling wall extends to the end face of the valve core II. When the first valve core is abutted against the second valve core, the throttling wall forms a throttling channel with the straight cylinder surface.

In the expansion valve, the number of the straight cylindrical surfaces is five, the distance from one end of the throttling wall, which is close to the two end surfaces of the valve core, to the two end surfaces of the valve core is equal to the sum of the lengths of the five straight cylindrical surfaces, the outer wall of the plug connector is also circumferentially provided with a conical surface, and one end of the throttling wall, which faces the two end surfaces of the valve core, is connected with one end with a larger diameter of the conical surface. Five straight cylinder surfaces respectively form five-stage flow control, so that the control precision is higher, and along with the relative separation and movement of the first valve core and the second valve core, the conical surface can enter the straight cylinder surfaces before the throttle wall is sequentially opposite to each straight cylinder wall, so that the flow is gradually changed, and the flow change is buffered.

In the expansion valve, a conical transition surface is arranged between two adjacent straight cylindrical surfaces, one end of the transition surface with a larger diameter is connected with the straight cylindrical surface with a larger diameter, and one end of the transition surface with a smaller diameter is connected with the straight cylindrical surface with a smaller diameter. The flow controlled by different straight cylinder surfaces is different, so that the flow can jump in the transition process, and the transition surface can buffer the flow change, so that the flow is steadily increased or reduced.

In the expansion valve, the first valve core is internally provided with a stepped surface arranged around the orifice of the orifice, the two end surfaces of the first valve core or the stepped surface of the first valve core are provided with buffer grooves arranged around the plug, when the orifice wall is opposite to the straight cylinder surface, a throttle channel is formed, and the buffer grooves are communicated with the throttle channel. The existing valve core I and the valve core II are not provided with buffer grooves, the step surface of the valve core I is propped against the end surface of the valve core II, at the moment that the step surface of the valve core I is separated from the end surface of the valve core II, the refrigerant acts on the whole end surface of the valve core II, namely, the acting area suddenly becomes large, so that the stress change of the valve core II is large, and further, the relative movement speed change of the valve core I and the valve core II is large, so that the flow change is large.

Compared with the prior art, the expansion valve has the following advantages:

1. the plug connector is matched with the throttling hole, so that five-stage flow control of the refrigerant can be realized, and the flow control precision is higher.

2. The throttling wall is in a straight cylinder shape, so that the passing sectional area of the throttling channel is not changed in the process of gradually staggering the throttling wall from the opposite direction of the cylindrical surface or the straight cylinder surface, the flow change of the refrigerant is small, namely the expansion valve can realize the accurate control of the flow of five stages of the refrigerant, and the flow change is small in the flow control process of each stage, and the flow control precision is high.

3. The plug connector is also provided with two conical surfaces, and when the valve core I and the valve core II are relatively far away from each other, the cross section area of a throttling channel formed by the conical surfaces and the throttling wall is gradually increased, so that a buffering effect is achieved, namely, the larger conical surface can realize primary flow buffering, and the smaller conical surface can realize secondary flow buffering.

Drawings

Fig. 1 is a structural sectional view of a two-way expansion valve.

Fig. 2 is an enlarged view of the structure at a in fig. 1.

Fig. 3 is a schematic partial structure of the bi-directional expansion valve in the first stage flow buffering stage.

Fig. 4 is a schematic partial structure of the bi-directional expansion valve in the second stage flow buffering stage.

Fig. 5 is a schematic partial structure of the bi-directional expansion valve in the first stage flow precise control stage.

Fig. 6 is a schematic partial structure of the bi-directional expansion valve in the second stage flow precise control stage.

Fig. 7 is a schematic partial structure of the bi-directional expansion valve in the third stage flow precise control stage.

Fig. 8 is a structural elevation view of the second spool.

Fig. 9 is a structural sectional view of a two-way expansion valve in the second embodiment.

Fig. 10 is an enlarged view of the structure at B in fig. 9.

Fig. 11 is a structural cross-sectional view of the one-way expansion valve in the third embodiment.

In the figure, 1, a valve body; 2. a valve core I; 21. an orifice; 22. a plug section; 23. a throttle passage; 24. a step surface; 25. a straight cylinder surface; 26. a buffer chamber; 3. a valve core II; 31. a plug; 311. a cylindrical surface; 312. conical surface; 313. a transition surface; 32. a throttle unit; 33. a liquid passing groove; 4. a buffer tank; 5. a throttle wall; 6. a limit column; 61. a through hole; 7. a first spring; 8. and a second spring.

Detailed Description

The following are specific embodiments of the present invention and the technical solutions of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

Embodiment one:

as shown in fig. 1, the bidirectional expansion valve comprises a tubular valve body 1, a first valve core 2 and a second valve core 3 are slidably arranged in the valve body 1, two ends in the valve body 1 are fixedly connected with a limiting post 6, through holes 61 are formed in the limiting post 6 along the axial direction, limiting steps are formed in the peripheral wall of the limiting post 6, the first valve core 2 and the second valve core 3 are located between the two limiting posts 6, a first spring 7 is arranged between the first valve core 2 and one limiting post 6, one end of the first spring 7 abuts against the first valve core 2, the other end abuts against the limiting step of the limiting post 6, a second spring 8 is arranged between the second valve core 3 and the other limiting post 6, one end of the second spring 8 abuts against the second valve core 3, and the other end abuts against the limiting step of the other limiting post 6. Referring to fig. 2, a through orifice 21 is formed on the first valve core 2 along the axial direction, the second valve core 3 is columnar, a columnar plug connector 31 is formed on the end surface of the second valve core 3, the outer diameter of the plug connector 31 is smaller than that of the second valve core 3, under the action of a first spring 7 and a second spring 8, the plug connector 31 can be inserted into the orifice 21, three cylindrical surfaces 311 with different diameters and two conical surfaces 312 are formed on the outer wall of the plug connector 31, the three cylindrical surfaces 311 are sequentially arranged according to decreasing diameters along the plug connection direction, the two conical surfaces 312 are positioned at one end of the plug connector 31 close to the end surface of the second valve core 3, one end with smaller diameter of the conical surface 312 is connected with one end with smaller diameter of the other conical surface 312, and one end with larger diameter is connected with one end with smaller diameter of the other conical surface 312. The section of the orifice 21 extending inward from the orifice is a plug section 22, the plug section 22 has the same length as the plug 31 in the axial direction, the orifice 21 has a throttle wall 5 extending inward from the orifice, the throttle wall 5 is a straight cylinder of equal diameter, and the length of the throttle wall 5 is smaller than the plug section 22 but greater than the length of any cylindrical surface 311. The cylindrical surface 311 and the conical surface 312 can oppose the throttle wall 5 and form the throttle passage 23 when the plug 31 is inserted into the throttle hole 21.

Specifically, the taper of the conical surface 312 close to the end surface of the second valve element 3 is smaller than that of the other conical surface 312, a conical transition surface 313 is arranged between two adjacent cylindrical surfaces 311, one end of the transition surface 313 with a larger diameter is connected with the cylindrical surface 311 with a larger diameter, and one end of the transition surface 313 with a smaller diameter is connected with the cylindrical surface 311 with a smaller diameter. The valve core I2 is internally provided with a step surface 24 which is arranged around the orifice of the orifice 21, the end surface of the valve core II 3 or the step surface 24 of the valve core I2 is provided with a buffer groove 4 which is arranged around the plug-in connector 31, the buffer groove 4 is communicated with the orifice channel 23, the buffer groove 4 is provided with a flat bottom surface, the width of the buffer groove 4 is larger than the distance from the outer edge of the notch of the buffer groove 4 to the outer edge of the end surface of the valve core II 3, one end of the valve core I2 is provided with a buffer cavity 26 for the insertion of the valve core II 3, the step surface 24 is positioned between the buffer cavity 26 and the orifice 21, the orifice 21 is communicated with one end port of the valve body 1, the buffer cavity 26 is communicated with the other end port of the valve body 1, and the valve body 1 is combined with the structure shown in figure 9, the end face of the valve core II 3 is also circumferentially provided with three liquid passing grooves 33, the length direction of the liquid passing grooves 33 is arranged along the radial direction of the end face of the valve core II 3, the three liquid passing grooves 33 are circumferentially and uniformly distributed, one end of each liquid passing groove 33 is communicated with the buffer groove 4, the other end of each liquid passing groove is communicated with the buffer cavity 26, when the valve core I2 abuts against the valve core II 3, the liquid passing grooves 33 can still enable the buffer groove 4 to be communicated with the buffer cavity 26, namely, the expansion valve still allows a small flow of refrigerant to pass through, so that the valve core I2 and the valve core II 3 cannot move relatively when the flow of the refrigerant is small, the opening and closing times of the valve core I2 and the valve core II 3 are reduced, abrasion among the two parts is reduced, and the service life is prolonged.

When the throughput of the refrigerant is smaller or the refrigerant does not pass through, the stepped surface 24 of the valve core I2 abuts against the end surface of the valve core II 3, the plug 31 is completely inserted into the orifice 21, the valve core I2 or the valve core II 3 is pushed by the refrigerant when the refrigerant passes through the expansion valve, so that the valve core II 3 and the valve core I2 relatively move away, the conical surface 312 with smaller taper is combined with the throttling channel 23 formed by the throttling wall 5, and the passing sectional area of the throttling channel 23 gradually becomes larger in the moving process, thereby playing a role of buffering and realizing primary flow buffering; as shown in fig. 4, with the relative movement of the first valve core 2 and the second valve core 3, the conical surface 312 with smaller taper moves out of the orifice 21 and is staggered with the throttle wall 5, the conical surface 312 with larger taper and the throttle wall 5 form a throttle channel 23, and the passing sectional area of the throttle channel 23 gradually becomes larger in the moving process, so that the buffer effect is achieved, and the secondary flow buffer is realized; as shown in fig. 5, with the relative movement of the first valve core 2 and the second valve core 3, the conical surface 312 with larger taper moves out of the orifice 21 to be staggered with the throttle wall 5, the cylindrical surface 311 with larger diameter is opposite to the throttle wall 5 and forms a throttle channel 23, and the passing sectional area of the throttle channel 23 is not changed in the moving process, so that the flow rate of the refrigerant is changed little, thereby realizing the accurate control of the first-stage flow rate; as shown in fig. 6, as the first valve core 2 and the second valve core 3 continue to move relatively, the cylindrical surface 311 with the largest diameter moves out of the throttle hole 21 and is staggered with the throttle wall 5, while the adjacent cylindrical surface 311 with relatively smaller diameter and the throttle wall 5 form a throttle channel 23 relatively, and the passing sectional area of the throttle channel 23 is not changed in the moving process, so that the flow rate of the refrigerant is changed little, thereby realizing the accurate control of the second-stage flow rate; as shown in fig. 7, along with the continuous relative movement of the first valve core 2 and the second valve core 3, the cylindrical surface 311 with smaller diameter moves out of the throttle hole 21 and is staggered with the throttle wall 5, the cylindrical surface 311 with the smallest diameter and the throttle wall 5 form a throttle channel 23 relatively, the passing sectional area of the throttle channel 23 cannot change in the moving process, the flow rate of the refrigerant is small, and therefore the accurate control of the third-stage flow rate is realized, and in the resetting moving process of the first valve core 2 and the second valve core 3 relatively close, the passing sectional area of the throttle channel 23 gradually becomes smaller in five stages, so that the buffer effect is better.

Embodiment two:

the structure of the two-way expansion valve is basically the same as that of the first embodiment, as shown in fig. 9 and 10, the difference is that five straight cylindrical surfaces 25 with different diameters are provided on the inner wall of the orifice 21 from the orifice inwards, the five straight cylindrical surfaces 25 are sequentially arranged from the orifice inwards according to the decreasing diameter, a convex throttling part 32 is provided on the outer wall of the plug 31 in the circumferential direction, the throttling part 32 is provided with a cylindrical throttling wall 5, when the plug 31 is inserted into the orifice 21, the throttling wall 5 can be opposite to the innermost straight cylindrical surface 25 of the orifice 21, the distance from the end of the throttling wall 5 near the end face of the second valve element 3 to the end face of the second valve element 3 is equal to the sum of the lengths of the five straight cylindrical surfaces 25, the diameter of the throttling wall 5 is smaller than the diameter of the straight cylindrical surface 25 with the smallest radial dimension, a conical surface 312 is provided on the outer wall of the plug 31, one end of the throttling wall 5 facing the end face of the second valve element 3 is connected with one end with the larger diameter of the conical surface 312, a conical transition surface 313 is provided between the adjacent straight cylindrical surfaces 25, and the end of the larger diameter of the transition surface 313 is connected with the smaller diameter of the straight cylindrical surface 25. The inner wall of the throttle hole 21 is provided with five straight cylindrical surfaces 25, so that a five-stage throttle channel 23 can be formed, further five-stage flow control of the refrigerant is realized, and in the resetting movement process of the valve core I2 and the valve core II 3 which are relatively close to each other, the passing sectional area of the throttle channel 23 is gradually reduced in five stages, so that the valve has a good buffering effect.

Embodiment III:

the one-way expansion valve is basically the same as the two-way expansion valve in the first embodiment, and is different in that, as shown in fig. 11, the two-way expansion valve comprises a tubular valve body 1, a valve core I2 is slidably arranged in the valve body 1, an orifice 21 with the same structure as that in the two-way expansion valve is axially arranged on the valve core I2, a limit post 6 is fixedly connected in the valve body 1, a through hole 61 is axially arranged on the limit post 6, a limit step facing the valve core I2 is arranged on the peripheral wall of the limit post 6, a spring I7 is arranged between the valve core I2 and the limit post 6, one end of the spring I7 is abutted against the valve core I2, the other end is abutted against the limit step, a valve core II 3 is fixedly connected in the valve body 1, and a plug connector 31 with the same structure as that in the two-way expansion valve is arranged on the valve core II 3.

The specific embodiments described herein are offered by way of example only to illustrate the spirit of the invention. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions thereof without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Although the terms of the valve body 1, the spool-2, the orifice 21, etc. are used more herein, the possibility of using other terms is not excluded. These terms are used merely for convenience in describing and explaining the nature of the invention; they are to be interpreted as any additional limitation that is not inconsistent with the spirit of the present invention.

Claims

1. The expansion valve comprises a valve core I (2) and a valve core II (3) which is columnar, wherein the valve core I (2) is provided with a through orifice (21), the end face of the valve core II (3) is provided with a plug connector (31) which is columnar and can be inserted into the orifice (21), the outer diameter of the plug connector (31) is smaller than that of the valve core II (3), the outer wall of the plug connector (31) is provided with at least two cylindrical surfaces (311) with different diameters, the cylindrical surfaces (311) are sequentially arranged in a decreasing diameter along the plugging direction, the part of the orifice (21) which extends inwards from the orifice to the axial length of the plug connector (31) is a plugging section (22), the orifice (21) is provided with a throttling wall (5) which extends inwards from the orifice, the throttling wall (5) is in a straight cylinder shape, the length of the throttling wall (5) is smaller than or equal to the length of the plugging section (22), and the inner diameter of the throttling wall (5) is smaller than the inner diameter of other positions of the plugging section (22), and when the plug connector (31) is inserted into the orifice (21), the throttling wall (31) is provided with at least one cylindrical surface (311) which can form a channel (23) opposite to the throttling wall.

2. Expansion valve according to claim 1, characterized in that the length of the throttle wall (5) is greater than or equal to the length of any cylindrical surface (311).

3. Expansion valve according to claim 1 or 2, characterized in that the cylindrical surfaces (311) are three, two conical surfaces (312) are further arranged on the outer wall of the plug connector (31), the two conical surfaces (312) are positioned at one end of the plug connector (31) close to the end face of the valve core II (3), one end of the conical surface (312) with smaller diameter is connected with the cylindrical surface (311) with the largest diameter, and the other end with larger diameter is connected with the end of the other conical surface (312) with smaller diameter.

4. An expansion valve according to claim 3, wherein the taper of the conical surface (312) near the end face of the second valve element (3) is smaller than the taper of the other conical surface (312).

5. Expansion valve according to claim 1 or 2, characterized in that between adjacent cylindrical surfaces (311) there is a conical transition surface (313), the end of the transition surface (313) with the larger diameter being connected to the cylindrical surface (311) with the larger diameter, and the end of the transition surface (313) with the smaller diameter being connected to the cylindrical surface (311) with the smaller diameter.

6. Expansion valve according to claim 1 or 2, characterized in that the first valve core (2) is internally provided with a step surface (24) which is arranged around the orifice of the orifice (21), the end surface of the second valve core (3) or the step surface (24) of the first valve core (2) is provided with a buffer groove (4) which is arranged around the plug-in connector (31), and the buffer groove (4) is communicated with the orifice channel (23).

7. The expansion valve according to claim 6, wherein one end of the first valve element (2) is provided with a buffer cavity (26) for inserting the second valve element (3), the step surface (24) is located between the buffer cavity (26) and the orifice (21), the orifice (21) is communicated with one end port of the valve body (1), the buffer cavity (26) is communicated with the other end port of the valve body (1), the end surface of the second valve element (3) is also circumferentially provided with a plurality of liquid passing grooves (33), one end of each liquid passing groove (33) is communicated with the buffer groove (4), and the other end of each liquid passing groove is communicated with the buffer cavity (26).

8. The expansion valve according to claim 7, wherein the length direction of the liquid passing groove (33) is arranged along the radial direction of the end face of the valve core II (3), three liquid passing grooves (33) are arranged, and the three liquid passing grooves (33) are uniformly distributed in the circumferential direction.

9. Expansion valve according to claim 1 or 2, characterized in that the orifice rim of the orifice (21) is provided with an arc-shaped chamfer in the circumferential direction.

10. An expansion valve comprises a valve core I (2) and a valve core II (3), wherein the valve core I (2) is provided with a through orifice (21), the end face of the valve core II (3) is provided with a columnar plug (31) which can be inserted into the orifice (21), the outer diameter of the plug (31) is smaller than that of the valve core II (3), the inner wall of the orifice (21) is internally provided with at least three straight cylinder surfaces (25) with different diameters, the at least three straight cylinder surfaces (25) are sequentially arranged from the orifice of the orifice (21) inwards according to the decreasing diameter, the outer wall of the plug (31) is provided with a cylindrical throttling wall (5) which can be opposite to the straight cylinder surface (25) at the innermost side of the orifice (21), the diameter of the throttling wall (5) is smaller than that of the straight cylinder surface (25) with the smallest radial dimension, and when the plug (31) is inserted into the orifice (21), the throttling wall (5) can be opposite to the straight cylinder surfaces (25) and form a throttling channel (23).

11. Expansion valve according to claim 10, wherein the plug (31) has a protruding throttling part (32) circumferentially on the outer wall, the outer peripheral wall of the throttling part (32) is the throttling wall (5), and the distance from the end of the throttling wall (5) close to the end face of the second valve element (3) is smaller than or equal to the sum of the lengths of the straight cylindrical surfaces (25).

12. Expansion valve according to claim 10, characterized in that the plug (31) has a protruding throttle (32) in the circumferential direction on the outer wall, the outer circumferential wall of the throttle (32) being the throttle wall (5), one end of the throttle wall (5) extending to the end face of the second valve element (3).

13. The expansion valve according to claim 11, wherein the number of the straight cylindrical surfaces (25) is five, the distance from one end of the throttling wall (5) close to the end face of the valve core II (3) is equal to the sum of the lengths of the five straight cylindrical surfaces (25), the outer wall of the plug connector (31) is also circumferentially provided with a conical surface (312), and one end of the throttling wall (5) facing the end face of the valve core II (3) is connected with one end with a larger diameter of the conical surface (312).

14. Expansion valve according to claim 10 or 11 or 12, characterized in that between adjacent straight cylindrical surfaces (25) there is a conical transition surface (313), the end of the transition surface (313) with the larger diameter being connected to the straight cylindrical surface (25) with the larger diameter, and the end of the transition surface (313) with the smaller diameter being connected to the straight cylindrical surface (25) with the smaller diameter.

15. Expansion valve according to claim 10 or 11 or 12, characterized in that the first valve element (2) is internally provided with a step surface (24) which is arranged around the orifice of the orifice (21), the end surface of the second valve element (3) or the step surface (24) of the first valve element (2) is provided with a buffer groove (4) which is arranged around the plug-in connector (31), when the throttling wall (5) is opposite to the straight cylinder surface (25), a throttling channel (23) is formed, and the buffer groove (4) is communicated with the throttling channel (23).

16. The expansion valve according to claim 15, wherein one end of the first valve element (2) is provided with a buffer cavity (26) for inserting the second valve element (3), the step surface (24) is located between the buffer cavity (26) and the orifice (21), the orifice (21) is communicated with one end port of the valve body (1), the buffer cavity (26) is communicated with the other end port of the valve body (1), the end surface of the second valve element (3) is also circumferentially provided with a plurality of liquid passing grooves (33), one end of each liquid passing groove (33) is communicated with the buffer groove (4), and the other end of each liquid passing groove is communicated with the buffer cavity (26).

17. Expansion valve according to claim 16, characterized in that the length direction of the liquid passing groove (33) is arranged along the radial direction of the end face of the valve core II (3), three liquid passing grooves (33) are arranged, and the three liquid passing grooves (33) are uniformly distributed in the circumferential direction.

18. Expansion valve according to claim 10 or 11 or 12, characterized in that the orifice rim of the orifice (21) is provided with an arc-shaped chamfer in the circumferential direction.