Patent Description:
In general vehicles, in order to provide a comfortable interior environment with less noise, noise reduction during the operation of car air conditioners, for instance, is required. There are various causes of the noise generated by the operation of car air conditioners, but the expansion valve used for refrigeration cycles is sometimes noted as a noise generation source. In this type of expansion valve, the high-pressure refrigerant emits a characteristic operation sound when the high-pressure refrigerant is decompressed by the orifice and travels to the evaporator, and particularly in cases in which the expansion valve is installed on the partition wall that separates the engine compartment from the vehicle compartment, this operation sound is easily transmitted to the inside of the vehicle, such that there is demand for noise reduction. In order to reduce such noise, various proposals have been made regarding expansion valves. <CIT> discloses an expansion valve, comprising an inlet port to which the high pressure refrigerant is sent and an outlet port, which are formed at a valve body of the expansion valve. A valve material which controls an opening of a valve hole is arranged at a valve chamber. A throttle member is fixed to the outlet port by a caulking part, rectifies the refrigerant flowing out of the side of an evaporator, and reduces the noise caused by the breakage of an air bubble. <CIT> discloses an expansion valve for a vehicle air conditioner, wherein a space-expandable rectifying plate member is installed on the downstream high-pressure refrigerant passage of a throttle passage. The space-expandable rectifying plate member includes a rectifying plate body portion and a spacer portion extending from a circumference of one side edge of the rectifying plate body portion. <CIT> discloses an expansion valve wherein a piping member is provided with a squeeze member fitted and adhered to the piping member. The squeeze member has a stepped cylindrical form which has a large diameter attaching part provided at the front end side, and a small diameter part extended in the refrigerant/coolant flow direction of the evaporator.

Patent Document <NUM> discloses an expansion valve in which a rectifier with a throttle opening is provided in the outlet passage leading toward the evaporator. According to such an expansion valve, when passing through the throttle opening, the air bubbles in the refrigerant are subdivided, thereby reducing the noise caused by the rupturing of these air bubbles.

In addition to the noise caused by the rupture of air bubbles, noise caused by turbulent flow of the refrigerant may occur, but by providing the rectifier, such noise can also be reduced. More specifically, the refrigerant throttled by the orifice of the expansion valve expands until the refrigerant reaches the outlet passage, and then the traveling direction of the refrigerant changes by approximately <NUM> degrees, which may invite the risk of turbulent flow which causes noise. Therefore, by throttling the expanded refrigerant once again with the rectifier throttle opening, it is possible to prevent the generation of turbulence and to achieve noise reduction. This is referred to as what is known as a "muffler effect".

Incidentally, in order to exhibit a sufficient muffling effect, it is desirable to enlarge the volume of the space through which the refrigerant passes from the orifice to the rectifier as much as possible. On the other hand, in car air conditioners and the like, the miniaturization of components is prioritized, and it is desirable to miniaturize the expansion valve as much as possible. However, if the expansion valve is miniaturized, the volume of the space from the orifice to the rectifier is also restricted, and there is a risk that the muffler effect cannot be sufficiently exhibited.

It is an object of the present disclosure to provide an expansion valve which is compact and can further enhance muffling performance.

The invention is defined by an expansion valve according to claim <NUM>.

In order to achieve the above object, the expansion valve according to the present invention includes a valve main body including an inlet passage configured to introduce a high-pressure refrigerant, a valve chamber configured to communicate with the inlet passage, an expansion chamber that includes an orifice configured to reduce a pressure of the refrigerant introduced into the valve chamber, and an outlet passage disposed downstream of the expansion chamber and configured to discharge the refrigerant that passes through the expansion chamber, a rectifier disposed in the valve main body and configured to partition the expansion chamber and the outlet passage, a valve member configured to open and close the orifice, and a valve member driving device configured to drive the valve member, wherein the rectifier includes a hollow convex portion projecting toward the outlet passage and a throttle hole formed at a distal end of the hollow convex portion.

According to the present invention, the hollow convex portion is cylindrical, and has an outer diameter less than an inner diameter of a pipe connected to the outlet passage.

Preferably, at least a portion of the hollow convex portion is disposed inside the pipe.

The rectifier is preferably formed by press forming a metallic plate.

According to the present disclosure, it is possible to provide an expansion valve which is compact and can further enhance muffling performance.

Referring now to the drawings, an expansion valve <NUM> according to an embodiment of the present disclosure will be described. It should be noted that in the following description of the embodiments and comparative examples, parts and members having the same functions are denoted by the same reference numerals, and redundant description of parts and members denoted by the same reference numerals is omitted.

In this specification, the direction from the valve body <NUM> to the actuation rod <NUM> is defined as the "upward direction" and the direction from the actuation rod <NUM> to the valve body <NUM> is defined as the "downward direction" on the paper surface of the drawings.

An overview of the expansion valve <NUM> in the present embodiment will be described with reference to <FIG>. <FIG> is a diagram that schematically illustrates the entire configuration of an expansion valve <NUM> according to the present embodiment together with a pipe connected to an evaporator. It should be noted that, in <FIG>, the portion corresponding to the power element <NUM> is illustrated in a side view, and the remaining portions are illustrated in a cross-sectional view. <FIG> is an enlarged view of an area AR around the orifice, where (a) is an enlarged view of the present embodiment, and (b) and (c) are enlarged views of the same portion in the comparative examples. <FIG> is a perspective view of the rectifier.

The expansion valve <NUM> comprises an aluminum valve main body <NUM> with a valve chamber VS, a valve body <NUM>, a biasing member <NUM>, an actuation rod <NUM>, and a ring spring <NUM>.

In addition to the valve chamber VS, the valve main body <NUM> includes a first flow path <NUM> and a second flow path <NUM>. The first flow path <NUM> is, for example, a supply-side flow path (also referred to as an inlet flow path), and the valve chamber VS is supplied with fluids through the supply-side flow path. The second flow path <NUM> is, for example, a discharge-side flow path (also referred to as an outlet flow path), and the fluid in the valve chamber VS is discharged out of the expansion valve through the discharge-side flow path. Connected to the second flow path <NUM> is a pipe H1 which extends to and is connected to an evaporator (not illustrated in <FIG>). On the outer periphery of the end of the pipe H1, an O-ring OR is arranged so as to abut against the inner wall of the second flow path <NUM>, thereby preventing leakage of the refrigerant.

A rectifier <NUM> is disposed near the entrance of the second flow path <NUM> of the valve main body <NUM> so as to enter the pipe H1. As illustrated in <FIG>, the rectifier <NUM> has a substantially top hat shape, and specifically, has a circular sheet portion <NUM> and a hollow cylindrically shaped hollow convex portion <NUM> integrally provided with the circular sheet portion <NUM>, and an opening (also referred to as a throttle hole) <NUM> formed at the distal end of the hollow convex portion <NUM>. It should be noted that the circular sheet portion <NUM> and the hollow convex portion <NUM> are eccentric to each other.

In the present embodiment, the rectifier <NUM> is formed by press-forming a plate material such as SUS, but the rectifier <NUM> may be formed of a resin. Alternatively, the circular sheet portion <NUM> and the hollow convex portion <NUM> may be separate bodies, which form the rectifier when joined together. The outer periphery of the circular sheet portion <NUM> is attached to the inner wall of the second flow path <NUM> by a method such as caulking or press-fitting.

In <FIG>, when the outer diameter of the hollow convex portion <NUM> is defined as D2 and the inner diameter of the pipe H1 is defined as D1, the relationship D2≦D1 is satisfied. Accordingly, as illustrated in <FIG>, the rectifier <NUM> can be assembled by causing the hollow convex portion <NUM> to enter into the interior of the pipe H1. However, in consideration of the assembly error with the pipe H1, it is more desirable to set a relationship of D2<D1 to ensure smooth assembly.

The valve body <NUM> is located in valve chamber VS. When the valve body <NUM> is seated on the valve seat <NUM> of the valve main body <NUM>, the first flow path <NUM> and the second flow path <NUM> are not in communication with each other. On the other hand, when the valve body <NUM> is separated from the valve seat <NUM>, the first flow path <NUM> and the second flow path <NUM> are in communication.

The biasing member <NUM> biases the valve body <NUM> towards the valve seat <NUM>. The biasing member <NUM> is, for example, a coiled spring.

The lower end of the actuation rod <NUM> contacts the valve body <NUM>. In addition, the actuation rod <NUM> can press the valve body <NUM> in the opening direction against the biasing force of the biasing member <NUM>. When the actuation rod <NUM> moves downwards, the valve body <NUM> is separated from the valve seat <NUM> and the expansion valve <NUM> is opened.

The space from the small diameter orifice <NUM> located downstream of the valve seat <NUM> to the opening <NUM> of the rectifier <NUM> is referred to as expansion chamber EX. That is, the rectifier <NUM> partitions the expansion chamber EX and the second flow path <NUM>. A bolt hole <NUM> used for fastening to another member is formed by interposing thin walls with respect to the expansion chamber EX.

The ring spring <NUM> is a vibration isolating member for suppressing the vibration of the actuation rod <NUM>. The ring spring <NUM> is disposed between the outer peripheral surface <NUM> of the actuation rod <NUM> and the inner peripheral surface 26a of the valve main body <NUM>. However, the ring spring <NUM> is not necessarily required.

A return flow path (also known as a return passage) <NUM> is formed in the upper portion of the valve main body <NUM>. Connected to the return flow path <NUM> is a pipe H2 that extends from the evaporator (not illustrated in <FIG>). On the outer periphery of the end of the pipe H2, an O-ring OR is arranged so as to abut against the inner wall of the return flow path <NUM>, thereby preventing leakage of the refrigerant.

Next, the effect of the present embodiment will be described via comparison with a comparative example. First, in Comparative Example <NUM> illustrated in <FIG>, the rectifier 30A is composed of only the circular sheet portion <NUM>, and the circular sheet portion <NUM> has an opening <NUM>. The opening <NUM> is made to have the same shape as the opening <NUM> of the rectifier <NUM>. In addition, the volume of the expansion chamber EX is relatively small compared to the present embodiment.

Also, in Comparative Example <NUM> as illustrated in <FIG>, using the so-called muffler effect, it is possible to reduce, to some extent, the passage noise emitted by the refrigerant after passing between the valve seat <NUM> and the valve body <NUM> and the orifice <NUM> at the time of valve opening.

On the other hand, as illustrated in Comparative Example <NUM> as illustrated in <FIG>, even if the same rectifier 30A is used, the so-called muffler effect is enhanced by increasing the volume of the expansion chamber EX, and a larger passage noise reduction effect can be expected. However, when the bolt hole <NUM> is provided in the valve main body <NUM>, for example, the volume of the expansion chamber EX is limited to avoid interference, and it is difficult to obtain a further reduction in passage noise.

Therefore, in the present embodiment, by using a rectifier <NUM> having the hollow convex portion <NUM> as illustrated in <FIG>, the volume of the expansion chamber EX including the orifice can be further enlarged, and the so-called muffler effect can be further enhanced, so that a greater passage noise reduction effect can be expected. In particular, by inserting a portion of the hollow convex portion <NUM> into the pipe H1, it is possible to suppress interference with the pipe H1, and to maintain a compact outer shape of the valve main body <NUM> while increasing the volume of the expansion chamber EX. Such effects are of particular importance in the expansion valves used for car air conditioners and the like. It should be noted that the diameter and length of the hollow convex portion <NUM>, the area and the shape of the opening <NUM>, and the like can be selected to be optimal according to the specifications of the products. In addition, the diameter of the holes of the expansion chamber EX (the diameter perpendicular to the central axes of the hollow convex portion <NUM>) is not limited to the size illustrated in <FIG>, and can be any diameter.

An application example of the expansion valve <NUM> will be described with reference to <FIG> is a schematic cross-sectional view that schematically illustrates an example in which the expansion valve <NUM> in the above-described embodiment is applied to a refrigerant circulation system <NUM>.

In the embodiment illustrated in <FIG>, the expansion valve <NUM> is fluidly connected to a compressor <NUM>, a condenser <NUM>, and an evaporator <NUM>.

In addition, the expansion valve <NUM> includes a power element <NUM> and a return flow path <NUM> in addition to the valve main body <NUM>, the valve body <NUM>, the biasing member <NUM>, the actuation rod <NUM>, the ring spring <NUM>, the first flow path <NUM> and the second flow path <NUM>. The valve body <NUM> and the valve seat <NUM> constitute a valve member, and the power element <NUM>, the biasing member <NUM> and the actuation rod <NUM> constitute a valve member driving device.

Referring to <FIG>, the refrigerant pressurized by the compressor <NUM> is liquefied by the condenser <NUM>, and sent to the expansion valve <NUM>. In addition, the refrigerant adiabatically expanded in the expansion valve <NUM> is delivered to the evaporator <NUM> through the pipe H1, and heat exchanged in the evaporator <NUM> with the air flowing around the evaporator. The refrigerant returning from the evaporator <NUM> is returned from the pipe H2 to the compressor <NUM> through the expansion valve <NUM> (more specifically, the return flow path <NUM>).

Expansion valve <NUM> is supplied with high-pressure refrigerant from the condenser <NUM>. More specifically, the high pressure refrigerant from the condenser <NUM> is supplied to the valve chamber VS via the first flow path <NUM>. In the valve chamber VS, the valve body <NUM> is disposed opposite the valve seat <NUM>. The valve body <NUM> is supported by a valve body support <NUM>, and the valve body support <NUM> is biased upwardly by the biasing member <NUM>, (for example, a coiled spring). In other words, the valve body <NUM> is biased by the biasing member <NUM> toward the valve closing direction. The biasing member <NUM> is disposed between the valve body support <NUM> and the biasing member receiving member <NUM>. In the embodiment illustrated in <FIG>, the biasing member receiving member <NUM> is a plug that is mounted on the valve main body <NUM> to seal the valve chamber VS.

When the valve body <NUM> is seated on the valve seat <NUM> (in other words, when the expansion valve <NUM> is in the closed state), the first flow path <NUM> on the upstream side of the valve chamber VS and the second flow path <NUM> on the downstream side of the valve chamber VS are not in communication with each other. On the other hand, when the valve body <NUM> is separated from the valve seat <NUM> (in other words, when the expansion valve <NUM> is in an open state), the refrigerant supplied to the valve chamber VS is delivered to the evaporator <NUM> through the second flow path <NUM>. At this time, by entering the expansion chamber EX having a large volume after passing through the orifice <NUM> and then passing through the opening <NUM> of the rectifier <NUM>, the passage noise is effectively reduced. The switching between the closed state and the open state of the expansion valve <NUM> is carried out by the actuation rod <NUM> connected to the power element <NUM>.

In the embodiment illustrated in <FIG>, the power element <NUM> is disposed at the upper end of the expansion valve <NUM>. The power element <NUM> includes an upper lid member <NUM>, a receiving member <NUM> that has an opening at its center, and a diaphragm (not illustrated in the figures) disposed between the upper lid member <NUM> and the receiving member <NUM>. The first space surrounded by the upper lid member <NUM> and the diaphragm is filled with a working gas.

The lower surface of the diaphragm is connected to the actuation rod via a diaphragm support member. Therefore, when the working gas in the first space is liquefied, the actuation rod <NUM> moves upward, and when the liquefied working gas is vaporized, the actuation rod <NUM> moves downward. In this way, the switching between the open state and the closed state of the expansion valve <NUM> is carried out.

The second space between the diaphragm and the receiving member <NUM> is in communication with the return flow path <NUM>. Therefore, the phase (gas phase, liquid phase, or the like) of the working gas in the first space changes in accordance with the temperature and pressure of the refrigerant flowing through the return flow path <NUM>, and the actuation rod <NUM> is driven. In other words, in the expansion valve <NUM> illustrated in <FIG>, the quantity of the refrigerant supplied from the expansion valve <NUM> to the evaporator <NUM> is automatically adjusted in accordance with the temperature and pressure of the refrigerant returning from the evaporator <NUM> to the expansion valve <NUM>. In the embodiment illustrated in <FIG>, the return flow path <NUM> communicates with the concave portion <NUM>, and the concave portion <NUM> is disposed below the return flow path <NUM>.

Claim 1:
An expansion valve (<NUM>) comprising:
a valve main body (<NUM>) including:
an inlet passage configured to introduce a high-pressure refrigerant,
a valve chamber (VS) configured to communicate with the inlet passage,
an expansion chamber (EX) that includes an orifice (<NUM>) configured to reduce a pressure of the refrigerant introduced into the valve chamber (VS), and
an outlet passage disposed downstream of the expansion chamber (EX) and configured to discharge the refrigerant that passes through the expansion chamber (EX);
a rectifier (<NUM>) disposed in the valve main body (<NUM>) and configured to partition the expansion chamber (EX) and the outlet passage;
a valve member configured to open and close the orifice (<NUM>); and
a valve member driving device configured to drive the valve member;
wherein the rectifier (<NUM>) has a substantially top hat shape and includes a circular sheet portion (<NUM>) and a hollow cylindrically shaped convex portion (<NUM>) projecting toward the outlet passage and integrally provided with the circular sheet portion (<NUM>), and a throttle hole (<NUM>) formed at a distal end of the hollow convex portion (<NUM>),
characterized in that the hollow convex portion (<NUM>) has an outer diameter (D2) smaller than an inner diameter (D1) of a pipe (H1) connected to the outlet passage,
the circular sheet portion (<NUM>) and the hollow convex portion (<NUM>) are eccentric to each other,
and the outer periphery of the circular sheet portion (<NUM>) is attached to the inner wall of the outlet passage by caulking or press-fitting.