CN115479139A

CN115479139A - Valve core for expansion valve and expansion valve

Info

Publication number: CN115479139A
Application number: CN202110660403.9A
Authority: CN
Inventors: 苏健; 付文华; G·科斯奈德; A·维格
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2021-06-15
Filing date: 2021-06-15
Publication date: 2022-12-16

Abstract

The invention provides a valve core for an expansion valve and the expansion valve. The spool includes: a body having a surface of revolution, the surface of revolution having an axis; a central passage through the body in a direction perpendicular to the axis; a first groove recessed from the surface of revolution into the body but not formed through the body, the first groove beginning at the surface of revolution at one end and communicating with the central passage at the other end, wherein the first groove comprises a first portion distal from the central passage and a second portion communicating the first portion and the central passage, the second portion having an increased width relative to the first portion, the width being the dimension of the first groove measured on the surface of the body in a direction parallel to the axis. The expansion valve can quickly supply required amount of refrigerant in a throttling and pressure reducing mode so as to realize required refrigeration effect as soon as possible.

Description

Valve core for expansion valve and expansion valve

Technical Field

The present invention relates to an expansion valve for controlling the flow of refrigerant into a refrigeration device, and more particularly to a valve cartridge for an expansion valve and an expansion valve including such a valve cartridge.

Background

The flow of refrigerant into the refrigeration unit has a direct influence on the operating characteristics and refrigeration effect of the refrigeration unit. Refrigeration units typically employ an expansion valve to control the flow of refrigerant into the refrigeration unit. Existing expansion valves typically include a valve body and a ball valve cartridge mounted in the valve body. As shown in fig. 1, a valve cartridge 1 of a conventional expansion valve generally includes a spherical body 3, a central passage 5 penetrating the body 3 is provided in the body 3 substantially along a diameter direction of the body 3, a first groove 7 is formed inward on the body 3 from one end of the central passage 5 on a plane of a diameter of the body 3, a second groove 9 is formed inward on the body 3 from the other end of the central passage 5 on the same plane of the diameter of the body 3, the second groove 9 extends in an opposite direction to the first groove 7, that is, the first groove 7 is formed extending from one end of the central passage 5 toward one side of the central passage 5, and the second groove 9 is formed extending from the other end of the central passage 5 toward the other side of the central passage 5. The first and

second grooves

7, 9 extend from the surface of the body 3 to the central passage 5 with increasing depth. Fig. 2 to 4 schematically show the state of the prior art valve cartridge 1 for an expansion valve in different operating conditions in the valve body 11. In fig. 2 the valve spool is rotated to a position where all central channels, the first groove 7 and the second groove 9 are completely closed, i.e. the first and second connections on the valve body of the expansion valve are covered to the maximum extent by the valve spool. In fig. 3 the spool is rotated to a position where the first and

second grooves

7, 9 are open, i.e. the first and second ports on the valve body of the expansion valve are at least partly communicating the first and second grooves. In fig. 4 the spool is rotated to a position where the central passage is fully open, i.e. the first and second connections on the valve body of the expansion valve are covered to a minimum by the spool. . The valve cartridge of fig. 2-4 is generally taken along line AA of fig. 1. The arrows in fig. 3 and 4 indicate the flow direction and the flow amount of the refrigerant. Fig. 5 schematically shows a flow rate curve of a conventional expansion valve having the valve element shown in fig. 1, wherein the abscissa indicates a rotation angle of the expansion valve, the ordinate indicates a passage area (also referred to as a flow passage area) where the expansion valve is open, and the origin indicates a position at a maximum opening degree (flow passage area) where the center passage is fully opened, and the opening degree (flow passage area) becomes smaller as the rotation angle of the valve element increases until the position where the expansion valve is fully closed (i.e., the flow passage area is zero).

The section indicated with thin lines on the left in the flow curve in fig. 5 corresponds to the interval in which the expansion valve is switched on by means of the central channel or a part of the central channel. The section indicated by a bold line on the right in the flow curve in fig. 5 corresponds to the interval in which the expansion valve is switched on by means of the groove or a part of the groove. Since the central passage 5 is cylindrical with a large diameter and the first and

second grooves

7, 9 have a relatively small and substantially constant width, the flow passage area of the expansion valve changes sharply non-linearly when the expansion valve is switched on by means of the central passage or a part of the central passage, and slowly approximately linearly when the expansion valve is switched on by means of the grooves or a part of the grooves. This means that the amount of refrigerant entering the refrigeration device through the expansion valve also changes sharply non-linearly (approximately parabolic) when the expansion valve is switched on by means of the central channel or a part of the central channel, and slowly approximately linearly when the expansion valve is switched on by means of the groove or a part of the groove.

Under certain working conditions, a relatively large amount of refrigerant is required to be throttled and depressurized by an expansion valve and then boiled so as to achieve the required refrigeration effect as soon as possible. However, a slow change in the amount of refrigerant entering the refrigeration apparatus in the expansion region of the existing expansion valve, such as a slow increase, cannot meet the requirements of actual conditions, resulting in failure to achieve the desired refrigeration effect in time.

Accordingly, there is a need for an improvement of existing valve spools for expansion valves.

Disclosure of Invention

It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art by providing a valve cartridge for an expansion valve that, in addition to providing an approximately linear slow change in the amount of refrigerant flowing through the expansion valve in the expansion region, also provides a relatively rapid change in the amount of refrigerant flowing through the expansion valve in the expansion region.

According to an aspect of the present invention, there is provided a valve cartridge for an expansion valve, comprising:

a body having a surface of revolution, the surface of revolution having an axis;

a central passage through the body in a direction perpendicular to the axis;

a first groove recessed into the body from the surface of revolution but not formed through the body, the first groove starting at the surface of revolution at one end and communicating with the central passage at the other end,

wherein the first groove comprises a first portion distal from the central passage and a second portion communicating the first portion and the central passage, the second portion having an increased width relative to the first portion, the width being a dimension of the first groove measured on the surface of the body in a direction parallel to the axis.

Preferably, a second groove is formed on the body inwardly recessed from the other end of the central passage on the plane without penetrating the body, the second groove having the same structure as the first groove but being symmetrically formed in the opposite direction.

Preferably, the surface of revolution comprises a cylindrical or spherical surface.

Preferably, the circumferential extension of the second portion in said plane is at least one quarter of the circumferential extension of the first portion.

Preferably, the second portion has a substantially constant width at different circumferential positions.

Preferably, the second portion is defined by two parallel flat side walls and an arc-shaped bottom wall between the flat side walls, the first portion forming a shape of a spiral involute such that a depth of the first portion, which is a dimension of the first groove measured from a surface of the spool to the bottom wall in a radial direction of the spool, gradually deepens toward the central passage and is recessed from the bottom wall of the second portion and extends toward the central passage.

Preferably, the second portion has a gradually increasing width from the first portion towards the central passage.

Preferably, the second portion is a portion of a cylindrical passage overlapping the first portion and the central passage, the second portion being formed obliquely with respect to the central passage.

According to another aspect of the present invention, there is provided an expansion valve, wherein the expansion valve comprises:

a valve body having a first port and a second port;

the valve core is rotatably arranged in the valve cavity of the valve body, the first interface and the second interface are respectively communicated with the valve cavity, the valve core is the valve core, and the revolution surface of the valve core is in sliding sealing contact with the valve body; and

a shaft coupled to the spool, the shaft capable of being driven to rotate the spool about an axis of the spool between a first position in which the first and second ports are maximally covered by the surface of revolution, an intermediate region in which the first and second ports at least partially communicate with the first slot, and a second position in which the first and second ports are minimally covered by the surface of revolution.

Preferably, in the first position, the first port and the second port are disconnected from communication, so that the expansion valve is closed.

According to the valve core for an expansion valve of the present invention, since the first groove includes the first portion away from the central passage and the second portion communicating the first portion and the central passage, the second portion has an increased width with respect to the first portion, a required amount of refrigerant can be rapidly supplied in a throttling and depressurizing manner as needed to achieve a desired cooling effect as quickly as possible.

Drawings

Fig. 1 schematically shows a side view of a prior art valve spool for an expansion valve;

fig. 2 shows in a simplified cross-sectional view a state of the art valve spool for an expansion valve mounted in place in a valve body, in which both the central passage and the groove of the valve spool are completely closed;

fig. 3 shows, in a simplified cross-sectional view, another state of a prior art valve spool for an expansion valve mounted in place in a valve body, wherein the groove of the valve spool is open;

fig. 4 shows in a simplified cross-sectional view a state of the art valve spool for an expansion valve mounted in place in a valve body, in which the central passage of the valve spool is fully opened;

FIG. 5 schematically illustrates a flow curve for a prior art expansion valve having the valve cartridge of FIG. 1;

fig. 6 shows in a simplified schematic view the main structure of an expansion valve according to the invention;

fig. 7 schematically shows in a perspective view a valve spool for an expansion valve according to a first embodiment of the present invention;

fig. 8 schematically shows in a perspective view a valve spool for an expansion valve according to a second embodiment of the present invention;

fig. 9 schematically shows, in a perspective view, a valve spool for an expansion valve according to a third embodiment of the present invention; and

fig. 10 schematically shows a flow curve of an expansion valve having a valve cartridge according to the present invention.

Detailed Description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but it should be understood that the drawings are only for purposes of illustrating the invention and are not to be construed as limiting the invention.

Fig. 6 shows in a simplified schematic view the main structure of an expansion valve according to the invention. As shown in fig. 6, the expansion valve 20 according to the present invention includes a valve body 21, a valve chamber 23 formed in the valve body 21, a valve spool 25 disposed in the valve chamber 23, and a first port 27 and a second port 29 formed in the valve body 21 on both sides of the valve chamber 23. The valve spool 25 is held in the valve chamber 23 of the valve body 21 by the valve cover 31. The rotary shaft 33 is connected to the top end of the spool 25 through the bonnet 31. A sealing member 35 is further provided in the valve chamber 23 and between the valve body 21 and the valve spool 25 to prevent leakage of the refrigerant. The rotation shaft 33 may be rotated by a motor (not shown) through a transmission (not shown) to drive the valve core 25 to rotate, such that the expansion valve is completely closed, the groove is opened to communicate with the first port 27 and the second port 29, or the central passage is opened to communicate with the first port 27 and the second port 29.

Fig. 7 schematically shows a valve spool for an expansion valve according to a first embodiment of the present invention in a perspective view. As shown in fig. 7, the valve spool 25 for an expansion valve according to the first embodiment of the present invention generally includes a generally spherical body 37. Although body 37 may be a standard sphere, it is preferred that the bottom and top ends of body 37 be truncated to form an approximate sphere. A protrusion 39 is formed at the tip of the body 37, and an elongated groove 41 is provided in the protrusion 39. The flat extension 43 at the end of the shaft 33 is insertable into the elongated slot 41 in the body 37 to rotate the valve spool 25 about its axis OO'. A central passage 45 is provided through the body 37 in the body 37 generally in a direction perpendicular to the axis OO'. The central passage 45 is preferably disposed along a diameter of the body. A first groove 47 is formed on the body 37 recessed inwardly from one end of the central passage 45 on a plane perpendicular to the axis OO' of the spool 25 and passing through the central axis of the central passage 45 without penetrating the body, the first groove 47 being a groove having one end starting from the outer surface of the body 37 and the other end opening into the central passage 45. It should be understood that it is also possible for the first groove 47 to be formed on a plane perpendicular to the axis OO' of the spool 25 and parallel to the central axis of the central passage 45. Of course, it is also contemplated that the first groove 47 is not formed on a plane perpendicular to the axis OO' of the spool 25 and passing through or parallel to the central axis of the central passage 45. Alternatively, a second groove (not visible in fig. 7) is formed inwardly on the body 37 from the other end of the central passage 45 on a plane perpendicular to the vertical central axis of the body 37, the second groove being formed in the opposite direction to the first groove, i.e., the first groove 47 is formed extending from the end visible from the central passage 45 in fig. 7 toward the right side of the central passage 45, and the second groove is formed extending from the other end not visible from the central passage 45 toward the left side of the central passage 45. Preferably, the first groove 47 is formed symmetrically to the second groove.

Since the second groove is formed symmetrically to the first groove 47 and has the identical structure, the first groove 47 is described below with reference to fig. 7, and the description of the second groove is omitted. According to the invention, the first slot 47 comprises a first portion 47a remote from the central passage 45 and a second portion 47b communicating the first portion 47a with the central passage 45, the first portion 47a being a groove recessed towards the inside of the body 37 but not penetrating the body 37, having a substantially constant width a substantially smaller than the diameter of the central passage 45. The second portion 47b is also a recess recessed inwardly of the body 37, having a width b that is substantially constant and greater than the width a of the first portion 47 a. The width of the second portion 47b should be selected such that the expansion valve is switched on by the second portion 47b of the first tank and the second portion of the second tank to ensure that the refrigerant can be throttled down to boil. Although the second portion 47b may be formed to have a circular arc-shaped inner wall, the groove-shaped second portion 47b may be formed with two parallel flat side walls 47c for the convenience of processing, and thus the second portion 47b is defined by the two parallel flat side walls 47c and the circular arc-shaped bottom wall 47d therebetween. It will be appreciated that it is also possible that the bottom wall 47d between two opposite flat side walls 47c forms a flat bottom wall. In fig. 7, the bottom wall 47d of the first portion 47a is formed in the shape of a spiral involute such that the depth of the first portion 47a of the first groove gradually deepens toward the central passage 45. And thus also from the bottom wall 47d of the second portion 47b and extends to the central passage 45. In the present application, the width of the first groove refers to a dimension of the first groove measured on the surface of the body in a direction substantially parallel to the axis OO' of the spool 25. In the present application, the depth of the first groove refers to the size of the first groove measured from the surface to the bottom wall of the spool 25 in the radial direction of the spool.

Fig. 8 schematically shows a valve spool for an expansion valve according to a second embodiment of the present invention in a perspective view. The valve spool 25 for an expansion valve according to the second embodiment of the present invention shown in fig. 8 is substantially the same as the valve spool 25 for an expansion valve according to the first embodiment of the present invention shown in fig. 7, except for the second portion 47b of the first groove 47. For the sake of brevity, the description of the same portions of the valve spool 25 for an expansion valve according to the second embodiment of the present invention shown in fig. 8 as those of the valve spool 25 for an expansion valve according to the first embodiment of the present invention shown in fig. 7 will be omitted. As shown in fig. 8, in the valve spool 25 for an expansion valve according to the second embodiment of the present invention, the second portion 47b that communicates the first portion 47a with the central passage 45 is also a groove that is recessed inward of the body 37, but the second portion 47b has a gradually increasing width b from the first portion 47a toward the central passage 45 and the width b is greater than the width a of the first portion 47a, and thus the second portion 47b appears to be approximately trumpet-shaped. The width of the second portion 47b should also be selected such that the expansion valve is switched on by the second portion 47b of the first tank and the second portion of the second tank to ensure that the refrigerant can be throttled down to boil. Although the second portion 47b may be formed to have a circular-arc-shaped inner wall, the groove-shaped second portion 47b may be formed with two inclined flat sidewalls 47c for the convenience of processing, and thus, the second portion 47b is defined by the two inclined flat sidewalls 47c and the bottom wall 47d therebetween. It should be understood that the bottom wall 47d between the two inclined flat side walls 47c may be an arc-shaped bottom wall, but is preferably formed as a flat bottom wall for ease of processing. The groove-shaped second portion 47b may gradually increase in depth from the first portion 47a toward the central passage 45.

Fig. 9 schematically shows a valve spool for an expansion valve according to a third embodiment of the present invention in a perspective view. The valve spool 25 for an expansion valve according to the third embodiment of the present invention shown in fig. 9 is substantially the same as the valve spool 25 for an expansion valve according to the first embodiment of the present invention shown in fig. 7, except for the second portion 47b of the first groove 47. For the sake of brevity, the description of the same portions of the valve spool 25 for an expansion valve according to the third embodiment of the present invention shown in fig. 9 as those of the valve spool 25 for an expansion valve according to the first embodiment of the present invention shown in fig. 7 will be omitted. As shown in fig. 9, in the valve spool 25 for an expansion valve according to the third embodiment of the present invention, the second portion 47b communicating the first portion 47a with the center passage 45 includes a part of a cylindrical passage overlapping the first portion 47a and the center passage 45. The use of cylindrical channels facilitates machining. Preferably, the second portion 47b, which is a portion of the cylindrical passage, is formed obliquely with respect to the central passage 45. The diameter of the second portion 47b, which is part of the cylindrical passage, should be chosen such that the expansion valve ensures that the refrigerant can be throttled down to boil when switched on by the second portion 47b of the first groove and the second portion of the second groove.

In order to ensure that the second portion 47b of the first groove effects a variation in the flow rate of refrigerant, the circumferential extension of the second portion 47b in a plane perpendicular to the axis OO' of the spool 25 and passing through the central axis of the central passage 45 is at least a quarter of the circumferential extension of the first portion 47a, preferably at least a third of the circumferential extension of the first portion 47a, and more preferably a half of the circumferential extension of the first portion 47 a.

Although the present invention has been described in the above preferred embodiment by way of example with a valve cartridge having a generally spherical body, it will be understood by those skilled in the art that the body of the valve cartridge is not limited to a spherical shape, and other bodies having surfaces of revolution, such as a cylinder or cone, are also possible, provided that the body of the valve cartridge is capable of making sliding sealing contact with the valve body.

Fig. 10 schematically shows a flow curve of an expansion valve having a valve cartridge of the present invention as shown in fig. 7, 8 or 9. Although the specific parameters of the central passage, the first portion and the second portion of the groove of the spool shown in fig. 7, 8 or 9 may be different and the flow curves of the expansion valve using the three different spools shown in fig. 7, 8 or 9 may be slightly different according to different usage requirements of the expansion valve, the overall trend of the flow curves of the expansion valve using the three different spools shown in fig. 7, 8 or 9 is substantially the same. The abscissa of fig. 10 represents the rotation angle of the expansion valve, and the ordinate represents the passage area (also referred to as flow passage area (mm)) of the expansion valve opening ² ) The origin point represents a position at which the center passage is fully opened at the maximum opening degree (flow passage area), and the opening degree (flow passage area) becomes smaller as the rotation angle of the spool increases, up to a position at which the expansion valve is fully closed (i.e., the flow passage area is zero). The section indicated by a thin line on the left in the flow curve in fig. 10 corresponds to the region in which the expansion valve is mainly switched on by means of the central channel. The two segments indicated by bold lines on the right in the flow curve in fig. 10 correspond to the expansionThe valve is mainly connected by means of the first and/or second tank, wherein the left one of the two sections corresponds to the interval in which the expansion valve is mainly connected by means of the second part of the first and/or second tank, and the right one of the two sections corresponds to the interval in which the expansion valve is mainly connected by means of the first part of the first and/or second tank. It can be seen that both the flow curve of the expansion valve being mainly switched on by means of the second portion of the first and/or second groove and the flow curve of the expansion valve being mainly switched on by means of the first portion of the first and/or second groove are approximately linear, but the flow curve of the expansion valve being mainly switched on by means of the second portion of the first and/or second groove has a steeper slope with respect to the flow curve of the expansion valve being mainly switched on by means of the first portion of the first and/or second groove. This means that the flow passage area of the expansion valve changes rapidly approximately linearly when the expansion valve is mainly switched on by means of the second part of the first and/or second groove, whereas the flow passage area of the expansion valve changes slowly approximately linearly when the expansion valve is mainly switched on by means of the first part of the first and/or second groove. Thus, the amount of refrigerant entering the cooling device through the expansion valve changes rapidly approximately linearly when the expansion valve is switched on primarily by means of the second portion of the first and/or second groove, whereas the amount of refrigerant entering the cooling device through the expansion valve changes slowly approximately linearly when the expansion valve is switched on primarily by means of the first portion of the first and/or second groove.

Although the above preferred embodiment describes three different forms of the second portion of the groove, it should be understood that the second portion of the groove is not limited to the above three forms, and any form of the second portion having an increased width with respect to the first portion of the groove and capable of boiling refrigerant flowing through the expansion valve by throttling decompression when the expansion valve is turned on may be used.

In this way, under certain conditions when a relatively large amount of refrigerant is required to boil after being throttled and depressurized by the expansion valve, the expansion valve according to the present invention may be controlled to be switched on through the second portion of the groove to rapidly supply a required amount of refrigerant to achieve a desired cooling effect as quickly as possible.

The valve cartridge according to the invention does not require much modification with respect to the design of existing valve cartridges and is particularly easy to machine. The valve cartridge according to the invention can be manufactured, for example, by processes such as disc milling, finger milling, etching or 3D printing. When the valve core is manufactured by a process such as disc milling, finger milling or etching, only one additional machining step for forming the second portion of the groove is required compared to the machining step of the existing expansion valve. Furthermore, it is easy to machine the second part of the tank from one machining direction.

While the invention has been described in detail in connection with the preferred embodiments thereof, it is to be understood that such detail is solely for that purpose and that no limitation of the invention is thereby intended. The scope of the invention is determined by the claims.

Claims

1. A valve cartridge for an expansion valve, comprising:

a body (37) having a surface of revolution having an axis (OO');

a central passage (45) through the body (37) in a direction perpendicular to the axis (OO');

a first groove (47) recessed from the surface of revolution into the body (37) but not formed through the body, the first groove (47) starting at one end from the surface of revolution and communicating at the other end with the central passage (45),

wherein the first groove (47) comprises a first portion (47 a) remote from the central passage (45) and a second portion (47 b) communicating the first portion (47 a) and the central passage (45), the second portion (47 b) having an increased width with respect to the first portion (47 a), the width being the dimension of the first groove measured on the surface of the body along a direction parallel to the axis (OO').

2. The valve spool for an expansion valve according to claim 1, wherein a second groove is formed on the body (37) inwardly recessed from the other end of the central passage (45) on the plane without penetrating the body, the second groove having the same structure as the first groove but being symmetrically formed in the opposite direction.

3. The valve cartridge for an expansion valve of claim 1, wherein the surface of revolution comprises a cylindrical surface or a spherical surface.

4. A valve spool for an expansion valve according to claim 1, wherein the circumferential extension of the second portion (47 b) in said plane is at least a quarter of the circumferential extension of the first portion (47 a).

5. A valve cartridge for an expansion valve according to any of claims 1-4, wherein the second portion (47 b) has a substantially constant width at different circumferential positions.

6. The valve spool for an expansion valve according to claim 5, wherein the second portion (47 b) is defined by two parallel flat side walls (47 c) and an arc-shaped bottom wall (47 d) between the flat side walls (47 c), and the first portion (47 a) forms a shape of a spiral involute such that a depth of the first portion (47 a) which is a dimension of the first groove measured from a spool surface to a bottom wall in a radial direction of the valve spool (25) gradually deepens toward the central passage (45) and is recessed from the bottom wall (47 d) of the second portion (47 b) and extends to the central passage (45).

7. A valve cartridge for an expansion valve according to any of claims 1 to 4, wherein the second portion (47 b) has a gradually increasing width from the first portion (47 a) towards the central passage (45).

8. A valve cartridge for an expansion valve according to any one of claims 1 to 4, wherein the second portion (47 b) is a portion of a cylindrical passage overlapping the first portion (47 a) and the central passage (45), the second portion (47 b) being formed obliquely with respect to the central passage (45).

9. An expansion valve, wherein the expansion valve comprises:

a valve body (21) having a first port (27) and a second port (29);

a valve core (25) rotatably arranged in a valve cavity (23) of the valve body (21), wherein the first interface (27) and the second interface (29) are respectively communicated with the valve cavity (23), the valve core (25) is the valve core according to any one of claims 1 to 8, and the revolution surface of the valve core (25) is in sliding sealing contact with the valve body (21); and

a shaft connected to the spool (25), the shaft being drivable to bring the spool (25) to rotate about its axis between a first position in which the first port (27) and the second port (29) are covered to a maximum extent by the surface of revolution, an intermediate region in which the first port (27) and the second port (29) communicate at least partially with the first groove, and a second position in which the first port (27) and the second port (29) are covered to a minimum extent by the surface of revolution.

10. An expansion valve according to claim 9, wherein in the first position the first port (27) and the second port (29) are disconnected from communication such that the expansion valve is closed.