Patent Description:
<FIG> shows the structure of a typical valve needle assembly of an electronic expansion valve. The valve needle assembly of the electronic expansion valve has a screw rod <NUM>', and the screw rod <NUM>' and the valve needle <NUM>' are connected in a floating manner via a sleeve <NUM>'. A second washer <NUM>' is arranged between the valve needle <NUM>' and the sleeve <NUM>'. A compression spring <NUM>' is mounted in the sleeve <NUM>', an upper end of the compression spring <NUM>' abuts against the bushing at a lower end of the screw rod <NUM>', and a lower end face of the compression spring <NUM>' abuts against the bearing <NUM>'.

The elastic load of the spring <NUM>' passes through the bearing <NUM>' and the steel ball <NUM>', and finally acts on the valve needle <NUM>'.

For the electronic expansion valve employing the valve needle assembly, the elastic load of the spring always acts between the screw rod and the valve needle, and the friction force experienced by the valve needle during the rotation of the screw rod is relatively large.

Therefore, those skilled in the art may optimize the design of the electronic expansion valve, to reduce the friction force experienced by the valve needle during the rotation of the screw rod. <CIT> discloses an electronic expansion valve according to the preamble of claim <NUM>.

An object of the present invention is to provide an electric valve, so as to reduce the friction force experienced by the valve needle during the rotation of the screw rod.

To achieve the above object, the following technical solutions are provided. An electronic expansion valve includes a valve needle screw rod assembly, the valve needle and screw rod assembly includes a valve needle, a valve needle sleeve, a washer portion, a spring, and a screw rod assembly; wherein.

In the electronic expansion valve according to the present invention, before the spring is further compressed, the valve needle is suspended on the screw rod assembly via the valve needle sleeve, thus the valve needle is not subjected to the elastic load of the spring, which reduces the friction force experienced by the valve needle during the rotation of the screw rod.

The above drawings include the following reference numerals:.

For those skilled in the art to better understand technical solutions of the present invention, the present invention will be further described hereinafter in detail in conjunction with the drawings and specific embodiments.

Referring to <FIG>, <FIG> is a sectional view showing an electronic expansion valve according to a first embodiment of the present invention in a fully closed state; <FIG> is a partial sectional view showing the electronic expansion valve according to the first embodiment of the present application in a fully open state; <FIG> is a partial sectional view showing a valve needle sealing portion and a valve port sealing portion according to the first embodiment of the electronic expansion valve of the present application just getting into contact with each other; <FIG> is a partial sectional view showing the electronic expansion valve according to the first embodiment of the present application at a critical position before a spring is further compressed; <FIG> is a partial sectional view of the electronic expansion valve according to the first embodiment of the present application in the fully closed state; <FIG> is a sectional view of showing a valve needle and screw rod assembly in <FIG>; and <FIG> is an exploded view showing the valve needle and screw rod assembly in <FIG>.

With specific reference to <FIG>, which is a sectional view showing an electronic expansion valve according to a first embodiment of the present invention in a fully closed state, in a specific embodiment, the electronic expansion valve according to the present application includes a valve body <NUM> and a stator coil <NUM>. The valve body <NUM> includes a valve needle and screw rod assembly <NUM>, a valve seat assembly <NUM>, a nut assembly <NUM>, a rotor assembly <NUM> and a housing <NUM>. The stator coil <NUM> of the electronic expansion valve is connected to a drive controller. After being energized, the drive controller sends a pulse drive signal to the stator coil <NUM>. The stator coil <NUM> generates a periodically changing magnetic field, thereby driving the rotor assembly <NUM> of the electronic expansion valve to rotate in a forward or backward direction. The rotor assembly <NUM> is fixedly connected with a screw rod <NUM> of the valve needle and screw rod assembly <NUM>. While the rotor assembly <NUM> rotates, the screw rod <NUM> is driven to rotate synchronously. The screw rod <NUM> of the valve needle and screw rod assembly <NUM> is provided with external threads, an inner hole of a nut <NUM> of the nut assembly <NUM> is provided with internal threads, and the screw rod <NUM> is threadedly engaged with the nut <NUM>. When the rotor assembly <NUM> rotates, the screw rod <NUM> moves in an axial direction, thus driving the valve needle and screw rod assembly <NUM> to realize opening and closing of a valve port <NUM>.

The valve seat assembly <NUM> according to this embodiment includes a valve seat <NUM>, a first connecting pipe portion <NUM>, a second connecting pipe portion <NUM>, a guide seat <NUM> and a connecting seat <NUM>. The first connecting pipe portion <NUM>, the second connecting pipe portion <NUM>, the guide seat <NUM> and the connecting seat <NUM> are fixedly assembled with the valve seat <NUM>. The first connecting pipe portion <NUM> and the second connecting pipe portion <NUM> serve as an inflow or outflow channel of a fluid medium of the electronic expansion valve, and are generally used to be connected with system piping when the electronic expansion valve is mounted in a refrigeration or heating system such as an air conditioner. The valve seat <NUM> is provided with a valve port <NUM> at a position close to a center of the second connecting pipe portion <NUM>, and a valve port sealing portion <NUM> is provided on an upper edge of the valve port <NUM>.

A central inner hole position of the guide seat <NUM> of the valve seat assembly <NUM> is provided with an inner hole guiding portion <NUM> that cooperates with an outer wall of the valve needle and screw rod assembly. When the electronic expansion valve is being opened or closed, the inner hole guiding portion <NUM> provides a guiding function for the valve needle and screw rod assembly.

The nut assembly <NUM> is coaxially arranged at an upper side of the valve seat assembly <NUM>. The nut assembly <NUM> includes a nut <NUM>, a nut connecting portion <NUM>, a slip ring <NUM> and a spiral guide rail <NUM>. The nut <NUM> may be fixedly connected to the valve seat assembly <NUM> via the nut connecting portion <NUM> by welding or the like. The slip ring <NUM> and the spiral guide rail <NUM> are arranged at an upper portion of an outer periphery of the nut <NUM>. The slip ring <NUM> is able to spirally rotate along the spiral guide rail <NUM> within a limited stroke range in an up and down direction. The slip ring <NUM> and the spiral guide rail <NUM> cooperate with the rotor assembly <NUM>, to realize control of the stroke of the electronic expansion valve between a fully open state and a fully closed state.

The rotor assembly <NUM> includes a rotor magnet <NUM>, a rotor connecting portion <NUM>, and a rotor stop portion <NUM> (the rotor stop portion <NUM> and the rotor magnet <NUM> may be integrally formed, in this embodiment, they are assembled together after being separately formed). The rotor assembly <NUM> may be fixedly connected to (for example, connected by welding) the screw rod <NUM> of the valve needle and screw rod assembly <NUM> via the rotor connecting portion <NUM>, the rotor assembly <NUM> is driven by the stator coil <NUM> to drive the screw rod <NUM> to rotate synchronously. The rotor stop portion <NUM> is arranged at an inner side of the rotor assembly <NUM>. The rotor stop portion <NUM> cooperates with the slip ring <NUM> and the spiral guide rail <NUM> on the nut <NUM>, to limit the rotation of the rotor assembly <NUM> to be within a determined stroke range.

In addition, the electronic expansion valve according to this embodiment further includes a housing <NUM> with an open end, the housing <NUM> is sleeved outside the rotor assembly <NUM>, and the open end of the housing <NUM> is sealingly welded to the connecting seat <NUM> located at the upper side of the valve seat assembly <NUM>, to form a sealed accommodating cavity.

The valve needle and screw rod assembly <NUM> mainly includes a valve needle <NUM>, a valve needle sleeve <NUM>, a washer portion <NUM>, a spring <NUM> and a screw rod assembly <NUM>. Specifically, referring to <FIG> and <FIG>, where <FIG> is a sectional view of the valve needle and screw rod assembly, and <FIG> is an exploded view of the valve needle and screw rod assembly.

The valve needle <NUM> and the valve needle sleeve <NUM> may be fixedly connected by welding, etc. One end of the valve needle <NUM> includes a valve needle sealing portion <NUM>, the valve needle sealing portion <NUM> is configured to cooperate with the valve port sealing portion <NUM> to close the valve port <NUM>. The valve needle sleeve <NUM> includes a peripheral wall portion <NUM> located on its outer periphery and a fitting portion <NUM> integrally formed with the peripheral wall portion <NUM>. Of course, the peripheral wall portion <NUM> and the fitting portion <NUM> may also be fixedly connected by welding, clamping, etc. In addition, an inner diameter of the peripheral wall portion <NUM> is larger than an inner diameter of the fitting portion <NUM>. After the valve needle <NUM> and the valve needle sleeve <NUM> are fixedly connected, an accommodating cavity A is formed. That is, the accommodating cavity A is defined by the valve needle <NUM> and the valve needle sleeve <NUM>.

The washer portion <NUM> in this embodiment may employ a combination of a split retaining ring and a washer. That is, in this embodiment, the washer portion <NUM> includes both a split retaining ring and a washer. Of course, starting from the functional principle of the present application, the split retaining ring of the washer portion <NUM> in this embodiment is not limited to the C-shaped split retaining ring shown in the figures, and other shapes of split retaining rings may also be used instead. Similarly, the washer in this embodiment is not limited to the circular ring-shaped washer in the figures, and may also be replaced by other retaining rings that play the same role, for example, a split retaining ring may also be used instead.

In this embodiment, when the valve needle sleeve <NUM> fixedly connected to the valve needle <NUM> and the screw rod <NUM> rotate relative to each other, rotational friction fitting surfaces mainly lie on upper and lower surfaces of the split retaining ring, or on upper and lower surfaces of the washer. In order to further reduce the frictional resistance due to the relative rotation, it is preferable to spray or plate a coating with lubrication and wear-resistant functions on the surfaces (for example, a coating containing polytetrafluoroethylene, or graphite, or molybdenum disulfide), which may increase the service life of the electronic expansion valve.

The screw rod assembly <NUM> includes a lower stop portion <NUM>, and the lower stop portion <NUM> abuts against the washer portion <NUM>. Specifically, in this embodiment, the screw rod <NUM> includes a below-spring groove portion <NUM>, and the below-spring groove portion <NUM> is formed by being recessed from a surface of the screw rod <NUM>. In this case, a lower flange portion <NUM> is formed on the screw rod assembly <NUM>. In this embodiment, the lower stop portion <NUM> is the lower flange portion <NUM>.

The washer portion <NUM> is arranged in the below-spring groove portion <NUM>, in this case, the washer portion <NUM> is limitedly connected to the below-spring groove portion <NUM>.

It should be noted that the lower flange portion <NUM> may also be formed in different ways. For example, the screw rod <NUM> is not provided with the below-spring groove portion <NUM>, and the lower flange portion <NUM> may be formed by a lower end of the screw rod <NUM> extending peripherally from the surface thereof. In this case, the lower flange portion <NUM> may still abut against the washer portion <NUM>.

In addition, the screw rod assembly <NUM> further includes an upper stop portion <NUM>, and the upper stop portion <NUM> abuts against the spring <NUM>. Specifically, in this embodiment, the screw rod assembly <NUM> includes an upper flange portion <NUM>, and the upper flange portion <NUM> extends peripherally from the surface of the screw rod <NUM>. The upper flange portion <NUM> and the screw rod <NUM> may be integrally formed, or fixedly connected by welding, etc. In this embodiment, the upper stop portion <NUM> is the upper flange portion <NUM>.

In addition, the spring <NUM> is sleeved on the screw rod <NUM>. Specifically, one end of the spring <NUM> abuts against the upper flange portion <NUM>, and another end of the spring <NUM> abuts against the washer portion <NUM>. Under the action of the spring <NUM>, the washer portion <NUM> abuts against the lower flange portion <NUM>. It should be noted that, the end of the spring <NUM> abuts against the upper flange portion <NUM> includes the case that the end of the spring <NUM> directly abuts against the upper flange portion <NUM>, and the case that the end of the spring <NUM> indirectly abuts against the upper flange portion <NUM>, for example, a retaining ring or another component is provided between the spring <NUM> and the upper flange portion <NUM>.

Since the washer portion <NUM> is limitedly connected to the below-spring groove portion <NUM>, due to the influence of the spring <NUM> on the washer portion <NUM>, the washer portion <NUM> abuts against the lower flange portion <NUM>.

In the electronic expansion valve according to this embodiment, the spring <NUM> is sleeved on the screw rod <NUM>, and an upper end of the spring <NUM> abuts against the upper stop portion <NUM>, and a lower end of the spring <NUM> abuts against the lower stop portion <NUM>. The cooperation of the spring <NUM> and the screw rod assembly <NUM> may relatively reduce the deflection of the spring <NUM>, thereby reducing wear caused by eccentricity.

In addition, the valve needle and screw rod assembly <NUM> according to this embodiment further includes a valve needle support portion <NUM>, and the valve needle support portion <NUM> abuts against the fitting portion <NUM>. Specifically, in this embodiment, the screw rod assembly <NUM> includes a bushing component <NUM>. The bushing component <NUM> includes a connecting hole portion <NUM>, a body portion <NUM>, and a suspension engagement portion <NUM>. The connecting hole portion <NUM> may have a through hole or a blind hole, and one end of the screw rod <NUM> may be fixedly connected to the connecting hole portion <NUM> by welding, interference fit, or the like.

The suspension engagement portion <NUM> extends peripherally around the body portion <NUM>, and an outer diameter of the suspension engagement portion <NUM> is larger than an outer diameter of the body portion <NUM>. In this embodiment, the valve needle support portion <NUM> is the suspension engagement portion <NUM>, and the outer diameter of the suspension engagement portion <NUM> is larger than the inner diameter of the fitting portion <NUM>.

In addition, when the valve port is fully opened or the like, a distance D1 between the suspension engagement portion <NUM> and the first retaining ring <NUM> is greater than or equal to a distance D2 between the suspension engagement portion <NUM> and an upper end of the fitting portion <NUM>.

A distance D1-D2 may be between <NUM> and <NUM>.

In this case, the valve needle <NUM> may be suspended on the suspension engagement portion <NUM> through the valve needle sleeve <NUM>. Since the valve needle <NUM> is suspended on the suspension engagement portion <NUM> via the valve needle sleeve <NUM>, the valve needle <NUM> is not subjected to the elastic load generated by the spring <NUM>.

Please specifically refer to <FIG> is a partial sectional view showing the electronic expansion valve according to the first embodiment of the present application in a fully open state. When the electronic expansion valve is in the fully open state, a stroke of the valve needle <NUM> from the valve port <NUM> is L. In this case, the valve needle and screw rod assembly <NUM> is at an uppermost end of its stroke, the spring <NUM> is in an initial compressed state, the slidable washer portion <NUM> provided on the valve needle and screw rod assembly <NUM> abuts on an upper surface of the lower flange portion <NUM>, and the valve needle <NUM> is not subjected to the elastic load generated by the spring <NUM>. The valve needle <NUM> is suspended on the suspension engagement portion <NUM> via the valve needle sleeve <NUM>. A lower surface of the washer portion <NUM> abuts against the upper surface of the lower flange portion <NUM>. In this case, there is still a certain amount of clearance D1-D2 between the lower surface of the washer portion <NUM> and an upper surface of the fitting portion <NUM>, so the valve needle is not subjected to the elastic load generated by the spring <NUM>. In this case, the valve needle <NUM> is suspended and supported by the suspension engagement portion <NUM> of the bushing component <NUM>.

In addition, as the rotor assembly <NUM> rotates, the screw rod <NUM> moves along the axial direction, and a distance between the valve needle sealing portion <NUM> of the valve needle <NUM> and the valve port sealing portion <NUM> of the valve port <NUM> also changes.

Please specifically refer to <FIG> is a partial sectional view showing the valve needle sealing portion and the valve port sealing portion according to the first embodiment of the electronic expansion valve of the present application just getting into contact with each other. The electronic expansion valve changes from the fully open state to a state that the valve needle sealing portion <NUM> just gets into contact with the valve port sealing portion 2111at this time, a downward displacement of the valve needle <NUM> is L. During this process, the spring <NUM> is always in its initial compressed state, the lower stop portion <NUM> provided on the screw rod <NUM> always abuts against the lower flange portion <NUM> of the screw rod assembly <NUM>, the valve needle <NUM> is not subjected to the elastic load generated by the compression spring <NUM> in this state, and the certain amount of clearance D1-D2 is still kept between the lower surface of the first retaining ring <NUM> and the upper surface of the fitting portion <NUM> of the valve needle sleeve <NUM>.

Please specifically refer to <FIG> is a partial sectional view showing the electronic expansion valve according to the first embodiment of the present application at a critical position before the spring is further compressed. Compared with the state in <FIG>, the screw rod <NUM> in <FIG> further performs a downward displacement amount of D1-D2. At this time, the lower surface of the washer portion <NUM> and the upper end of the fitting portion <NUM> of the valve needle sleeve <NUM> are just at a critical position of being in contact with each other, which is equivalent to that the spring <NUM> is at the critical position to be further compressed, and is also equivalent to that the valve needle <NUM> and the valve needle sleeve <NUM> are at the critical position to be subjected to the elastic load of the compression spring <NUM> that to be further compressed.

Please specifically refer to <FIG> is a partial sectional view of the electronic expansion valve according to the first embodiment of the present invention in the fully closed state. Compared with the state in <FIG>, the screw rod <NUM> in <FIG> is moved downward by a displacement amount of α, in this case, the lower surface of the washer portion <NUM> and the fitting portion <NUM> of the valve needle sleeve <NUM> tightly abut against each other, and the spring <NUM> has been further compressed; the valve needle sealing portion <NUM> of the valve needle and screw rod assembly <NUM> and the valve port sealing portion <NUM> of the valve seat assembly <NUM> are in contact with and pressed tightly against each other, the washer portion <NUM> provided on the screw rod <NUM> abuts against the upper surface of the fitting portion <NUM> of the valve needle sleeve <NUM>, and the valve needle <NUM> is subjected to the load of the elastic force generated by the spring <NUM> that is further compressed. In this case, the electronic expansion valve is in the fully closed state, the screw rod <NUM> is at a lowest position of its stroke, and the downward stroke of the screw rod <NUM> from the fully open state to the fully closed state is L+α.

Please specifically refer to <FIG> is a partial sectional view of an electronic expansion valve according to a second embodiment of the present invention in a fully open state.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function, description of the components in the first embodiment is also applicable to the second embodiment, and those of the second embodiment that differ from the first embodiment are described in detail hereinafter.

In this embodiment, the screw rod assembly <NUM> includes a lower stop portion <NUM>, and the lower stop portion <NUM> abuts against the washer portion <NUM>. Specifically, the screw rod assembly <NUM> includes a bushing component <NUM>. The bushing component <NUM> includes a connecting hole portion <NUM>, a body portion <NUM>, and a suspension engagement portion <NUM>. The connecting hole portion <NUM> may be a through hole or a blind hole. One end of the screw rod <NUM> may be fixedly connected with the connecting hole portion <NUM> by welding, interference fit, or the like.

According to the electronic expansion valve in this embodiment, the spring <NUM> is sleeved on the screw rod <NUM>, the upper end of the spring <NUM> abuts against the upper stop portion <NUM>, and the lower end of the spring <NUM> abuts against the lower stop portion <NUM>. The cooperation between the spring <NUM> and the screw rod assembly <NUM> may relatively reduce the deflection of the spring <NUM>, thereby reducing eccentric wear.

The suspension engagement portion <NUM> extends peripherally around the body portion <NUM>, and the outer diameter of the suspension engagement portion <NUM> is larger than the outer diameter of the body portion <NUM>. In this embodiment, the valve needle support portion <NUM> is the suspension engagement portion <NUM>, in this case, the outer diameter of the suspension engagement portion <NUM> is larger than the inner diameter of the fitting portion <NUM>. Therefore, the suspension engagement portion <NUM> is able to abut against the fitting portion <NUM> of the valve needle sleeve <NUM>.

In addition, unlike the first embodiment, the lower stop portion <NUM> in this embodiment is no longer the lower flange portion <NUM>. In this case, the lower stop portion <NUM> is the body portion <NUM> of the bushing component <NUM>. That is, in this embodiment, the body portion <NUM> and the washer portion <NUM> is able to abut against each other.

It is worth noting that "able" or "may" in the present application refers to a specific state, but does not mean all working states of the electronic expansion valve. For example, in this embodiment, the body portion <NUM> is able to abut against the washer portion <NUM>, which refers to a situation that that the valve port <NUM> is fully opened or the like.

Of course, in this case, the distance D1 between the suspension engagement portion <NUM> and the first retaining ring <NUM> and the distance D2 between the suspension engagement portion <NUM> and the upper end of the fitting portion <NUM> still satisfy D1≥D2.

The distance D1-D2 may be between <NUM>-<NUM>.

Please specifically refer to <FIG> is a partial sectional view showing an electronic expansion valve according to a third embodiment of the present application in a fully open state.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function, description of the components in the first embodiment is also applicable to the third embodiment, and those of the second embodiment that differ from the first embodiment are described in detail hereinafter.

In this embodiment, the screw rod assembly <NUM> includes a valve needle support portion <NUM>, and the upper surface of the valve needle support portion <NUM> may abut against the fitting portion <NUM> of the valve needle sleeve <NUM>. Specifically, the screw assembly <NUM> includes a valve needle support washer <NUM>. In addition, a valve needle support groove portion <NUM> and a valve needle support flange portion <NUM> are also provided on the screw rod <NUM>. The valve needle support groove portion <NUM> is recessed from the surface of the screw rod <NUM>. Thus, the valve needle support flange portion <NUM> located below the valve needle support groove portion <NUM> protrudes peripherally relative to the valve needle support groove portion <NUM>. The valve needle support washer <NUM> is assembled in the valve needle support groove portion <NUM>. Specifically, the valve needle support washer <NUM> and the valve needle support groove portion <NUM> are fixedly connected or limitedly connected.

It is worth noting that the valve needle support flange portion <NUM> may also be formed in other manners. For example, the screw rod <NUM> is not provided with the valve needle support groove portion <NUM>, and the valve needle support flange portion <NUM> may be formed by the lower end of the screw rod <NUM> extending peripherally around its surface. In this case, the valve needle support flange portion <NUM> is still able to abut against the valve needle support washer <NUM>.

In the electronic expansion valve according to this embodiment, the spring <NUM> is sleeved on the screw rod <NUM>, the upper end of the spring <NUM> abuts against the upper stop portion <NUM>, and the lower end of the spring <NUM> abuts against the lower stop portion <NUM>. The cooperation between the spring <NUM> and the screw rod assembly <NUM> may relatively reduce the deflection of the spring <NUM>, thereby reducing eccentric wear.

In this case, the valve needle support portion <NUM> is the valve needle support washer <NUM>, and the upper surface of the valve needle support washer <NUM> may abut against the fitting portion <NUM> of the valve needle sleeve <NUM>. When the valve port <NUM> is opened or the like, the valve needle <NUM> is able to be supported by the valve needle support washer <NUM> via the valve needle sleeve <NUM> fixedly connected to the valve needle <NUM>.

The difference from the first embodiment is that, the valve needle support portion <NUM> in this embodiment is no longer the suspension engagement portion <NUM>, in this case, the valve needle support portion <NUM> is the valve needle support washer <NUM>. That is, in this embodiment, the fitting portion <NUM> and the valve needle support washer <NUM> may abut against each other.

It is worth noting that the "able" or "may" in the present application refers to a specific state, but does not mean all states of the electronic expansion valve. For example, in this embodiment, the fitting portion <NUM> and the valve needle support washer <NUM> may abut against each other, which refers to the situation that the valve port <NUM> is fully opened or the like.

Of course, in this case, the distance D1 between the valve needle support washer <NUM> and the first retaining ring <NUM> and the distance D2 between the valve needle support washer <NUM> and the upper end of the fitting portion <NUM> still satisfy D1≥D2.

In order to further reduce a rotational frictional resistance of the fitting portion <NUM> relative to the screw rod <NUM>, a coating with lubricating and wear-resisting functions (for example, a coating containing polytetrafluoroethylene, graphite or molybdenum disulfide) may be sprayed or plated on the surface of the valve needle support washer <NUM>, so as to prolong the service life of the electronic expansion valve.

Please specifically refer to <FIG> is a partial sectional view showing an electronic expansion valve according to a fourth embodiment of the present invention in a fully open state.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function, description of the components in the first embodiment is also applicable to the fourth embodiment, and those of the fourth embodiment that differ from the first embodiment are described in detail hereinafter.

In this embodiment, the screw rod assembly <NUM> includes an upper stop portion <NUM>, and the upper stop portion <NUM> abuts against the spring <NUM>. Specifically, in this embodiment, the screw rod assembly <NUM> is equipped with an upper retaining ring <NUM>. In addition, the screw rod <NUM> is provided with an above-spring annular groove <NUM>. The above-spring annular groove <NUM> is recessed from the surface of the screw rod <NUM>, and the upper retaining ring <NUM> is assembled in the above-spring annular groove <NUM>. Specifically, the upper retaining ring <NUM> is fixedly connected or limitedly connected with the above-spring annular groove <NUM>, that is, it is clamped in the above-spring annular groove <NUM> for position limiting.

The difference from the first embodiment is that, the upper stop portion <NUM> in this embodiment is no longer the upper flange portion <NUM>, in this case, the upper stop portion <NUM> is the upper retaining ring <NUM>. That is, in this embodiment, the upper retaining ring <NUM> abuts against the spring <NUM>.

In this case, the spring <NUM> is sleeved on the shaft of the screw rod <NUM>, and the upper end of the spring <NUM> abuts against the lower end surface of the upper retaining ring <NUM>. It is worth noting that the present application does not limit the number of retaining rings of the upper retaining ring <NUM>. Specifically, the upper retaining ring <NUM> which is arranged in the above-spring annular groove <NUM> of the screw rod <NUM> may be formed by a split retaining ring, and one or more retaining rings may be further provided at a lower side of the split retaining ring.

Of course, in this case, the distance between the suspension engagement portion <NUM> and the lower flange portion <NUM> is D1, the distance between the suspension engagement portion <NUM> and the upper end of the fitting portion <NUM> is D2, which still satisfy D1≥D2.

In this embodiment, when relative rotation between the valve needle <NUM> and the screw rod <NUM> occurs, a rotational friction surface may be between the upper end of the spring <NUM> and the upper retaining ring <NUM>. In order to further reduce the frictional resistance of the relative rotation, a coating with lubricating and wear-resisting functions may be sprayed or plated on the surface of the upper retaining ring <NUM> (for example, a coating containing polytetrafluoroethylene, or graphite, or molybdenum disulfide), so as to increase the service life of the electronic expansion valve.

Please specifically refer to <FIG> is a partial sectional view showing an electronic expansion valve according to a fifth embodiment of the present invention in a fully open state.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function, the description of the components in the first embodiment is also applicable to the fifth embodiment, and those of the fifth embodiment that differ from the first embodiment are described in detail hereinafter.

The difference from the first embodiment is that in this embodiment, the number of the washer portion <NUM> is one. This embodiment illustrates that in the present application, the number of washers in the washer portion <NUM> is not limited.

Of course, in this case, the distance between the suspension engagement portion <NUM> and the washer portion <NUM> is D1, the distance between the suspension engagement portion <NUM> and the upper end of the fitting portion <NUM> is D2, which still satisfy D1≥D2.

Please specifically refer to <FIG> is a partial sectional view showing an electronic expansion valve according to a sixth embodiment of the present invention in a fully open state.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function, the description of the components in the first embodiment is also applicable to the sixth embodiment, and those of the sixth embodiment that differ from the first embodiment are described in detail hereinafter.

In this embodiment, a bushing washer <NUM> is further provided between the bushing component <NUM> and the valve needle sleeve <NUM>. When the valve needle <NUM> is not subjected to the elastic load generated by the spring <NUM>, the valve needle <NUM> and the valve needle sleeve <NUM> are suspended on the suspension engagement portion <NUM> of the bushing component <NUM> via the bushing washer <NUM>.

In this case, the valve needle support portion <NUM> is a bushing washer <NUM>, and the upper surface of the bushing washer <NUM> and the lower surface of the fitting portion <NUM> of the valve needle sleeve <NUM> may abut against each other.

In the electronic expansion valve according to this embodiment, the spring <NUM> is sleeved on the screw rod <NUM>, and the upper end of the spring <NUM> abuts against the upper stop portion <NUM>, and the lower end of the spring <NUM> abuts against the lower stop portion <NUM>. The cooperation between the spring <NUM> and the screw rod assembly <NUM> may relatively reduce the deflection of the spring <NUM>, thereby reducing eccentric wear.

This embodiment illustrates that: in the present application, the upper end of the suspension engagement portion <NUM> may abut against the fitting portion <NUM> of the valve needle sleeve <NUM>, which is not limited to direct abutment, but also includes indirect abutment between the two.

Of course, in this case, the distance between the bushing washer <NUM> and the washer portion <NUM> is D1, the distance between the bushing washer <NUM> and the upper end of the fitting portion <NUM> is D2, which still satisfy D1≥D2.

In order to further reduce the rotational friction resistance between the fitting portion <NUM> of the valve needle sleeve <NUM> and the screw rod <NUM>, preferably, a coating with lubricating and wear-resisting functions (for example, a coating containing polytetrafluoroethylene, graphite or molybdenum disulfide) may be sprayed or plated on the surface of the bushing washer <NUM>, so as to prolong the service life of the electronic expansion valve.

Please specifically refer to <FIG> is a partial sectional view showing an electronic expansion valve according to a seventh embodiment of the present invention in a fully open state.

It should be noted that the main object of the present application is to improve the valve needle and screw rod assembly <NUM> of the electronic expansion valve. For other parts of the electronic expansion valve such as the magnetic rotor assembly, the valve needle and screw rod assembly, the nut assembly, the stop device, etc., general technology may be used, and other electronic expansion valve structures that can achieve the same function may also be used.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function, the description of the components in the first embodiment is also applicable to the seventh embodiment, and those of the seventh embodiment that differ from the first embodiment are described in detail hereinafter.

For example, in this embodiment, the structure of the valve seat assembly <NUM> is slightly different. The valve seat assembly includes the valve seat <NUM>, the first connecting pipe portion <NUM>, the second connecting pipe portion <NUM>, and the guide seat <NUM> which are fixedly assembled. The nut assembly <NUM> in this embodiment is fixedly connected to the upper side of the valve seat assembly <NUM> (specifically connected to the upper side of the valve seat <NUM>) through the nut connecting portion <NUM>, preferably is fixedly connected by welding.

In this embodiment, the guide seat <NUM> cooperates with the valve needle and screw rod assembly <NUM>, and the guide seat <NUM> has a guiding function for the valve needle and screw rod assembly <NUM>.

Referring to <FIG> is a partial sectional view showing an electronic expansion valve according to an eighth embodiment of the present invention in a fully open state.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function, the description of the components in the first embodiment is also applicable to the eighth embodiment, and those of the eighth embodiment differ from the first embodiment are described in detail hereinafter.

In this embodiment, the valve seat assembly <NUM> includes the valve seat <NUM>, the first connecting pipe portion <NUM> and the second connecting pipe portion <NUM> which are fixedly assembled. A central inner hole position of the valve seat <NUM> of the valve seat assembly <NUM> is provided with an inner hole guide portion <NUM> that cooperates with the valve needle and screw rod assembly <NUM>. When the electronic expansion valve is being opened or closed, the inner hole guide portion <NUM> of the valve seat <NUM> provides a guiding function for the valve needle and screw rod assembly <NUM>. Specifically, the inner hole guide portion <NUM> of the valve seat <NUM> cooperates with the outer edge of the valve needle <NUM> and/or the peripheral wall portion <NUM> of the valve needle sleeve <NUM>, to provide guidance for the valve needle and screw rod assembly <NUM>.

Please specifically refer to <FIG> is a partial sectional view showing an electronic expansion valve according to a ninth embodiment of the present invention in a fully open state.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function, the description of the components in the first embodiment is also applicable to the ninth embodiment, and those of the ninth embodiment that differ from the first embodiment are described in detail hereinafter.

In this embodiment, the valve seat assembly <NUM> includes the valve seat <NUM>, the first connecting pipe portion <NUM>, the second connecting pipe portion <NUM>, and the connecting seat <NUM> which are fixedly assembled. The first connecting pipe portion <NUM> is fixedly connected to the connecting seat <NUM>, and the second connecting pipe portion <NUM> is fixedly connected to the valve seat <NUM>. The inner hole guide portion <NUM> in this embodiment is provided on an inner hole wall, located at an upper side of the valve port <NUM>, of the valve seat <NUM>. The inner hole guide portion <NUM> of the valve seat assembly <NUM> provides a guiding function for the valve needle and screw rod assembly <NUM>. When the electronic expansion valve is being opened and closed, the valve needle and screw rod assembly <NUM> cooperates with the inner hole guide portion 10b of the valve seat assembly, to realize the guiding function for the valve needle portion. Specifically, the inner hole guide portion <NUM> of the valve seat <NUM> cooperates with the outer edge of the valve needle <NUM> and/or the peripheral wall portion <NUM> of the valve needle sleeve <NUM>, to provide guidance for the valve needle and screw rod assembly <NUM>.

Please specifically refer to <FIG> is a schematic view showing the structure of a valve needle and screw rod assembly.

In the valve needle and screw rod assembly <NUM>, the structures of the valve needle <NUM> and the valve needle sleeve <NUM> are changed. The valve needle includes a step portion <NUM>, the peripheral wall portion <NUM> of the valve needle sleeve <NUM> is sleeved on the side surface of the step portion <NUM> and abuts against the step surface of the step portion <NUM>, and the fitting portion <NUM> is an annular protrusion extending inwardly from the inner wall of the peripheral wall portion <NUM>. In addition, compared with the above embodiment, the suspension engagement portion <NUM> is located at an upper end of the bushing component <NUM>, which makes it easier for the suspension engagement portion <NUM> to fit with the fitting portion <NUM> formed as above. In this case, the valve needle <NUM> and the valve needle sleeve <NUM> may be fixedly connected by welding, crimping connection, or the like. In this case, the distance between the suspension engagement portion <NUM> and the washer portion <NUM> of the spring is D1, the distance between the suspension engagement portion <NUM> and the upper end of the fitting portion <NUM> is D2, which still satisfy D1≥D2.

It should be noted that the orientation terms such as up, down, left, right in the embodiments are all based on the drawings of the description, which are introduced for the convenience of illustration; the ordinal numerals such as "first" and "second" in the names of the components are also introduced for the convenience of illustration, which do not intend to make any restriction on any order of the components.

Claim 1:
An electronic expansion valve, comprising a valve needle and screw rod assembly (<NUM>), the valve needle and screw rod assembly (<NUM>) comprising a valve needle (<NUM>), a valve needle sleeve (<NUM>), a washer portion (<NUM>), a spring (<NUM>) and a screw rod assembly (<NUM>); wherein
the valve needle (<NUM>) is fixedly connected to the valve needle sleeve (<NUM>), the valve needle sleeve (<NUM>) comprises a peripheral wall portion (<NUM>) and a fitting portion (<NUM>), and an inner diameter of the fitting portion (<NUM>) is smaller than an inner diameter of the peripheral wall portion (<NUM>);
the screw rod assembly (<NUM>) comprises a lower stop portion (<NUM>), a valve needle support portion (<NUM>) and an upper stop portion (<NUM>), and the lower stop portion (<NUM>) is configured to abut against the washer portion (<NUM>), characterised in that
the valve needle support portion (<NUM>) is configured to abut against the fitting portion (<NUM>) of the valve needle sleeve (<NUM>);
the upper stop portion (<NUM>) is configured to abut against the spring (<NUM>); and
in a case that the lower stop portion (<NUM>) abuts against the washer portion (<NUM>), a distance between the valve needle support portion (<NUM>) and the washer portion (<NUM>) is D1, a distance between the valve needle support portion (<NUM>) and an upper end of the fitting portion (<NUM>) is D2, and D1≥D2.