JP2001263864A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise generated when a large quantity of refrigerant flows through a passage hole. SOLUTION: Since the first passage 43a of a two-phase refrigerant passage 43 on the low pressure side is provided with a member 60 projecting toward a second passage 43b, significant pressure variation of refrigerant immediately after passing through a throttle passage hole 48 is damped when the refrigerant flows through the projecting member 60. Noise can be reduced by passing refrigerant through a block joint after pressure variation thereof is damped thereby suppressing vibration of the block joint.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expansion valve for adjusting the flow rate of refrigerant flowing into an evaporator such that the degree of superheat of the refrigerant at the evaporator outlet of a refrigeration cycle is maintained at a set value. For improvement.

[0002]

2. Description of the Related Art An expansion valve of this type is provided with a fine throttle between a high-pressure side liquid refrigerant passage into which a high-pressure side liquid refrigerant of a refrigeration cycle flows and a low-pressure side two-phase refrigerant passage connected to an evaporator inlet. By installing a passage hole, the liquid refrigerant is decompressed and expanded in this throttle passage hole, and the opening area of the throttle passage hole is adjusted by a valve driven by a diaphragm to adjust the flow rate of the refrigerant flowing into the evaporator. Is what you do.

The low-pressure two-phase refrigerant passage has a first passage located on the throttle passage hole side and a second passage located on the downstream side of the refrigerant flow in the first passage and having a passage cross-sectional area larger than the first passage.
A connecting part (for example, a block joint or the like) connecting the low-pressure two-phase refrigerant passage and the evaporator inlet is inserted into the second passage from the downstream side of the refrigerant flow.

[0004]

However, in the above-mentioned prior art, there is a problem that high-frequency noise is generated particularly when a large amount of refrigerant flows immediately after the start of the refrigeration cycle.

The cause of this noise will be explained. When the refrigerant decompresses and expands in the throttle passage hole of the expansion valve and changes from a liquid phase to a gas-liquid two phase, bubbles are generated and grow in the liquid refrigerant, and coalescence occurs. The split causes pressure fluctuations. Pressure fluctuations also occur when the droplet flow in the gas-liquid two-phase refrigerant collides with the wall surface.

[0006] The pressure fluctuation of the refrigerant thus generated is transmitted from the throttle passage hole to the low-pressure two-phase refrigerant passage, and further vibrates a connecting part connecting the low-pressure two-phase refrigerant passage to the evaporator inlet. Thus, it was found that noise was generated from the connection parts, the evaporator, and the like.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to reduce noise generated due to a large amount of refrigerant flowing through a throttle passage hole.

[0008]

In order to achieve the above object, according to the present invention, the opening area of the throttle passage hole (48) for decompressing and expanding the high-pressure side liquid refrigerant is adjusted. And a low-pressure two-phase refrigerant passage (43) that feeds the low-pressure two-phase refrigerant that has passed through the throttle passage hole (48) to the evaporator (5). The low-pressure two-phase refrigerant passage (43) is located on the first passage (43a) located on the throttle passage hole (48) side, and is located on the downstream side of the first passage (43a) in the refrigerant flow.
a) has a second passage (43b) having a passage cross-sectional area larger than that of the first passage (43a).
It is characterized by comprising a projecting member (60) projecting toward b).

Thus, the low-pressure two-phase refrigerant that has passed through the throttle passage hole (48) passes through the first passage (43a),
After passing through the protruding member (60), the refrigerant flows through the connecting part connecting the evaporator (5) and the expansion valve. Therefore, the refrigerant having a large pressure fluctuation immediately after passing through the throttle passage hole (48) The pressure fluctuation is attenuated while flowing through the protruding member (60), and the refrigerant having the pressure fluctuation attenuated can be circulated in the connection component.

[0010] Therefore, compared with the conventional expansion valve without the protruding member (60), the refrigerant having a small pressure fluctuation can be circulated in the connecting part (5a), and the vibration of the connecting part can be suppressed to reduce the noise. Can be reduced.

By the way, the effect of the pressure fluctuation of the refrigerant due to the flow through the passage is reduced as the passage cross-sectional area becomes smaller and the passage length becomes longer.

According to an experiment conducted by the present inventors, as in the second aspect of the present invention, the projecting member (60) is formed in a cylindrical shape, and the throttle passage of the low-pressure two-phase refrigerant passage (43) is formed. If the length (B) from the hole (48) to the protruding end surface of the protruding member (60) is set to be 1.5 times or more the inner diameter (A) of the protruding member (60), the refrigerant in the protruding member (60) will It has been found that pressure fluctuations are sufficiently damped.

According to the third aspect of the present invention, the projecting member (60) is connected to the expansion valve body (41a) forming the low-pressure two-phase refrigerant passage (43) by the low-pressure two-phase refrigerant passage (43).
Is injected from the downstream side of the refrigerant flow.

According to the fourth aspect of the present invention, the projecting member (60) is a rigid member (60a) having high rigidity, and a shock absorbing member having shock absorbing properties disposed on the inner surface of the rigid member (60a). (60b), the vibration force when the refrigerant having large pressure fluctuation collides with the protruding member (60) is internally attenuated by the buffer member (60b). Therefore, the pressure fluctuation of the refrigerant in the protruding member (60) can be further attenuated.

Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment)
The expansion valve of the present invention is applied to a temperature-type expansion valve of a vehicle air conditioner. FIG. 1 shows a refrigeration cycle of a vehicle air conditioner including the expansion valve. In the figure, reference numeral 1 denotes a compressor, which is driven by a vehicle engine (not shown) via an electromagnetic clutch 1a. A condenser 2 cools and condenses the gas refrigerant discharged from the compressor 1 with cooling air (outside air) blown by a fan (not shown).

Numeral 3 is a receiver for storing the liquid refrigerant condensed in the condenser 3 and discharging only the liquid refrigerant to its outlet side. Reference numeral 4 denotes a thermal expansion valve for decompressing and expanding the refrigerant from the receiver 3, and reference numeral 5 denotes an evaporator, which is accommodated in a case of an air conditioning unit (not shown) and cools and dehumidifies conditioned air blown by an air conditioning fan (not shown). Things.

The above-mentioned temperature type expansion valve 4 has a vertically elongated rectangular parallelepiped main body 41 formed of a metal such as aluminum. In the main body 41, a high-pressure side liquid refrigerant passage 42, a low-pressure side two-phase refrigerant passage 43, and a low-pressure side gas refrigerant passage 44 are formed. High-pressure side liquid refrigerant passage 42
Is connected to the outlet of the receiver 3 and a high-pressure liquid refrigerant is sent in. The low-pressure two-phase refrigerant passage 43 is connected to a refrigerant inlet (see FIG. 3) 5a of the evaporator 5, and the gas-liquid two-phase refrigerant after adiabatic expansion is sent out.

The low-pressure gas refrigerant passage 44 has one end connected to the outlet 5b (see FIG. 3) of the evaporator 5 and the other end connected to the suction side of the compressor 1. The gas refrigerant evaporated by heat exchange (heat absorption) passes.
A temperature sensing rod (heat stem) 45 made of a metal having good heat conductivity such as aluminum is arranged to penetrate the low-pressure side gas refrigerant passage 44, and a valve actuation rod 46 is provided at a lower end of the temperature sensing rod 45. A spherical valve element 47 is disposed so as to contact the lower end of the valve operating rod 46.

The high-pressure side liquid refrigerant passage 42 communicates with the low-pressure two-phase refrigerant passage 43 through a minute throttle passage hole 48 for reducing and expanding the high-pressure liquid refrigerant.
Is adjusted by a spherical valve element 47. Here, the pressure reducing mechanism of the expansion valve 4 is configured by the spherical valve element 47 and the throttle passage hole 48.

The upper end of the temperature sensing rod 45 is in contact with a diaphragm (pressure responsive member) 49.
As a result, the valve element 47 is urged in the valve opening direction (downward in FIG. 1). Here, the diaphragm 49 is a diaphragm case 5
0, and partitions the space inside the diaphragm case 50 into an upper first pressure chamber 51 and a lower second pressure chamber 52.

The upper first pressure chamber 51 is filled with a refrigerant that is substantially saturated vapor under the condition that the refrigeration cycle is operated. Accordingly, the temperature fluctuation (superheat degree fluctuation) of the refrigerant that has exited the evaporator 5, that is, the gas refrigerant that passes through the low-pressure gas refrigerant passage 44, is transmitted to the refrigerant in the first pressure chamber 51 through the temperature sensing rod 45. Accordingly, the refrigerant pressure in the first pressure chamber 51 changes.

On the other hand, the second pressure chamber 52 on the lower side in the diaphragm case 50 always communicates with the low-pressure side gas refrigerant passage 44 through a space 56 formed between the temperature sensing rod 45 and the main body 41, and 2 The inside of the pressure chamber 52 is a low pressure side gas refrigerant passage 4.
It has the same pressure as 4.

A coil spring (spring means) 53 for urging the valve body 47 in the valve closing direction is disposed in the high-pressure side liquid refrigerant passage 42, and one end of the coil spring 53 has a support base 54.
A spring force is applied to the valve body 47 through. Coil spring 5
The other end of 3 is supported by a metal plug 55, and the metal plug 55 is fixed to a screw hole of the main body 41 so as to be position-adjustable, and the mounting load of the coil spring 53 can be adjusted by adjusting the position of the metal plug 55.

With such a configuration, the valve element 47 is displaced by the balance between the pressures of the first and second pressure chambers 51 and 52 and the force of the coil spring 53, and the opening area of the throttle passage hole 48 (valve opening) Degree) is controlled to be optimal.

Next, the low-pressure side two-phase refrigerant passage 43, which is a main part of the present embodiment, will be described with reference to FIG. 2, which is a partially enlarged view of FIG.

The low pressure side 2 formed on the main body 41 of the expansion valve 4
The phase refrigerant passage 43 has a circular cross section extending in the left-right direction in FIG. 2 and has a first passage 43 a communicating with the throttle passage hole 48.
And a second passage 43b located downstream of the first passage 43a in the refrigerant flow and having a larger passage cross-sectional area than the first passage 43a.

The first passage 4 in the expansion valve body 41
An enlarged portion 41a for enlarging the passage cross-sectional area of the first passage 43a is formed at a portion forming the end of 3a, and a cylindrical projecting member 60 is press-fitted into the enlarged portion 41a from the downstream side of the refrigerant flow. Have been. Therefore, the protruding member 60 is disposed so as to protrude from the first passage 43a toward the second passage 43b.

The protruding member 60 is formed of a rigid material (eg, metal) and is disposed so as to protrude from the first passage 43a toward the second passage 43b. The projecting end surface of the projecting member 60 is formed so as to be located on the same plane as the side surface of the expansion valve 4. The inner diameter A of the protruding member 60 is formed to be the same size as the inner diameter of the first passage 43a. Further, in the low-pressure side two-phase refrigerant passage 43, the length B from the central axis position of the throttle passage hole 48 to the end face of the protruding member 60 is formed to be about 1.5 times the inner diameter A of the protruding member 60. I have.

Next, a connection structure between the expansion valve 4 and the evaporator 5 having the above structure will be described with reference to FIG.

A block joint (connecting part) 70 is provided between the expansion valve 4 and the evaporator 5 to allow the refrigerant to flow between them. In this embodiment, the block joint 70 has a rectangular parallelepiped shape formed by cutting or die-casting a metal such as aluminum, and is joined to the evaporator 5 by, for example, integral brazing. The valve 4 is fastened by fastening means such as a bolt.

Inside the block joint 70, an inlet passage 71 for allowing gas-liquid two-phase refrigerant to flow from the low-pressure two-phase refrigerant passage 43 of the expansion valve 4 to the refrigerant inlet 5a of the evaporator 5, and a refrigerant outlet of the evaporator 5 An outlet passage 72 through which the gas refrigerant flows from the portion 5b to the low-pressure gas refrigerant passage 44 of the expansion valve 4 is formed.

At the ends of the two passages 71 and 72 on the expansion valve 4 side, there are formed a cylindrical inlet insertion connection 73 and an outlet insertion connection 74 projecting toward the expansion valve 4 side, respectively. The inlet insertion connection 73 is connected to the second passage 4 of the expansion valve 4.
3b, and the outlet insertion connection portion 74 is inserted into the low-pressure side gas refrigerant passage 44. Therefore, the inlet insertion connection 7
3 and the projecting member 60 of the expansion valve 4 is located inside, and the inner peripheral surface of the inlet insertion connection portion 73 and the projecting member 6
A gap CL is formed between the outer peripheral surface of the first member and the outer peripheral surface of the first member.

The outer peripheral surfaces of both insertion connecting portions 73 are
Ring-shaped grooves 73a, 74a are respectively formed, and seal members (for example, elastic materials such as O-rings) 75, 76 are fitted into the grooves 73a, 74a, so that the space between the block joint 70 and the expansion valve 4 is provided. Is sealed to prevent leakage of the refrigerant.

A pipe connecting portion 80 is fastened to a surface of the expansion valve 4 opposite to the block joint 70 by fastening means such as bolts. Inside the pipe connection portion 80, an inlet passage 81 through which liquid refrigerant flows from the outlet of the receiver 3 to the high-pressure liquid refrigerant passage 42 of the expansion valve 4, and a low-pressure gas refrigerant passage 44 of the expansion valve 4 from the compressor 1. An outlet passage 82 for allowing the gas refrigerant to flow out is formed on the suction side.

An inlet insertion connection 83 and an outlet insertion connection 84 similar to those of the block joint 70 are formed in these two passages 81 and 82, respectively.
6 seals the space between the pipe connection portion 80 and the expansion valve 4.

Next, the operation of the above configuration will be described.
Now, the compressor 1 operates in the refrigeration cycle of FIG.
When the refrigerant is circulated in the cycle, the filled gas in the first pressure chamber 51 of the expansion valve 4 is supplied to the passage 4 via the temperature sensing rod 45.
Since the superheated gas refrigerant temperature at the evaporator outlet in 4 is conducted, the pressure in the first pressure chamber 51 becomes a pressure corresponding to the superheated gas refrigerant temperature in the passage 44, while the pressure in the first pressure chamber 52 becomes The refrigerant pressure in the passage 44 is obtained.

Accordingly, the valve body 47 is displaced by the balance between the pressure difference between the two chambers 51 and 52 and the mounting load of the spring 53 for pressing the valve body 47 upward. Then, the opening degree of the throttle passage hole 48 is adjusted by the displacement of the valve body 47, and the refrigerant flow rate is automatically adjusted. The superheat degree of the gas refrigerant at the outlet of the evaporator is maintained at a predetermined value by the adjusting operation of the refrigerant flow rate.

By the way, when the refrigerant decompressed and expanded in the throttle passage hole 48 of the expansion valve 4 changes from the liquid phase to the gas-liquid two phase,
Bubbles are generated, grown, coalesced, and split in the liquid refrigerant, causing pressure fluctuations. Further, pressure fluctuations are also generated by the collision of the droplet flow in the gas-liquid two-phase refrigerant with the wall surface of the expansion valve body 41. Then, the thus generated pressure fluctuation causes the block joint 70 to vibrate.

On the other hand, according to the configuration of the present embodiment,
The low-pressure side two-phase refrigerant that has passed through the throttle passage hole 48 flows through the block joint 70 after passing through the projecting member 60, so that the refrigerant having a large pressure fluctuation immediately after passing through the throttle passage hole 48. The pressure fluctuation is attenuated while flowing through the protruding member 60, and the refrigerant having the pressure fluctuation attenuated can flow through the block joint 70. Therefore, as compared with the conventional expansion valve in which the projecting member 60 is not provided, the block joint 70 due to the pressure fluctuation of the refrigerant
Vibration can be suppressed, and noise can be reduced.

Since the gap CL is formed between the projecting member 60 and the block joint 70, the vibration of the projecting member 60 due to the pressure fluctuation of the refrigerant can be prevented from being directly transmitted to the block joint 70. The vibration of the block joint 70 can be further suppressed.

In the protruding member 60, the gas-liquid two-phase refrigerant contains a plurality of droplets in the gas phase, so that the pressure fluctuation propagating in the gas phase collides with and disperses the droplets.
It attenuates its own pressure fluctuations. The effect of attenuating such pressure fluctuations increases as the cross-sectional area of the passage through which the gas-liquid two-phase refrigerant flows decreases and as the length of the passage through which the gas-liquid two-phase refrigerant flows increases.

Therefore, in the present embodiment, the inner diameter A of the protruding member 60 is formed to be the same size as the inner diameter of the first passage 43a. The first having a smaller passage cross-sectional area than the second passage 43b
Length B of the passage flowing through the passage 43a and the protruding member 60
, The damping effect of the pressure fluctuation as described above can be enhanced.

FIG. 4 shows the change in the noise level with respect to the change in the refrigerant mass flow rate at the start of the refrigeration cycle.
Indicates the characteristics of a conventional expansion valve having no protruding member 60. The noise was measured at a location approximately 10 cm away from the approximate center of the evaporator 5. The noise level is
It is a decibel noise measurement value measured on the basis of 2 kHz to 6.3 kHz OA.

In the case of the product of the present invention, it can be seen that the noise level at the start of the refrigeration cycle can be reduced as compared with the conventional product.

(Second Embodiment) In the first embodiment, the projecting member 60 is formed only of a rigid material (eg, metal). In the present embodiment, as shown in FIG. A cylindrical rigid member 60a formed of a rigid material (eg, metal) and a cushioning member 60b formed of a cylindrical material on the inner surface of the rigid member 60a with a shock absorbing material (eg, rubber). It consists of. When the cushioning member 60b is made of rubber, the cushioning member 60b may be fixed to the rigid member 60a by means such as printing.

As a result, the exciting force when the refrigerant having a large pressure fluctuation collides with the protruding member 60 is internally attenuated by the buffer member 60b. Therefore, the pressure fluctuation of the refrigerant in the protruding member 60 can be further attenuated, and the effect of suppressing the vibration of the block joint 70 and reducing the noise can be increased.

Although the cushioning member 60b is made of rubber in this embodiment, the cushioning member 60b is made of rubber.
Even if a resin or a metallic material (for example, aluminum) is used, the fluctuation of the refrigerant pressure can be internally attenuated by the buffer member 60 and the noise can be reduced. Therefore, the material of the buffer member 60b is not limited to the elastic body,
A material that can attenuate fluctuations in refrigerant pressure inside 0b can be used.

(Third Embodiment) In the first embodiment, the expansion valve 4 and the evaporator 5 are arranged close to each other.
Although a block joint is used as the connecting part 70 connecting between the evaporator 5 and the evaporator 5, in the present embodiment, the expansion valve 4 is used.
This is an example in which the present invention is applied to a case where the present invention is applied when the evaporator 5 and the evaporator 5 are not arranged close to each other. As shown in FIG.
The expansion valve 4 and the evaporator 5 are connected by pipes 77 and 78 using a pipe connection member.

(Fourth Embodiment) In the first embodiment, an inlet insertion connection portion 73 and an outlet insertion connection portion 74 are formed in the block joint 70, and these insertion connection portions 73 and 74 are connected to the second passage of the expansion valve 4. 43b and low-pressure side gas refrigerant passage 44
Has been inserted.

On the other hand, in the present embodiment, as shown in FIG.
The flange 79 is attached to the expansion valve 4 with bolts 79.
a) and the like.

(Other Embodiments) In the first and second embodiments, the projecting member 60 is formed separately from the main body 41 of the expansion valve 4 and press-fitted into the main body 41. Alternatively, it may be formed integrally with the main body 41 of the expansion valve 4. For example, an integral molding method by forging, cutting, or the like may be used.

In the first embodiment, the projecting end surface of the projecting member 60 is formed so as to be located on the same plane as the side surface of the expansion valve 4, but the present invention is limited to such a positional relationship. Instead, the protruding end surface of the protruding member 60 may be protruded from the side surface of the expansion valve 4 toward the evaporator 5 or may be in a positional relationship such that it does not protrude to the side surface of the expansion valve 4.

In the first and second embodiments, the evaporator 5
The main body 4 of the expansion valve 4 serves as a member for transmitting the temperature fluctuation (superheat degree fluctuation) of the outlet side gas refrigerant to the refrigerant in the first pressure chamber 51.
Although the temperature sensing rod 45 disposed inside 1 is used, the temperature sensing rod 45 is eliminated, and the temperature of the outlet side gas refrigerant of the evaporator 5 is changed by a temperature sensing cylinder arranged outside the main body 41 of the expansion valve 4. The present invention can be applied to a configuration in which the fluctuation (superheat degree fluctuation) is transmitted to the refrigerant in the first pressure chamber 51.

[Brief description of the drawings]

FIG. 1 is a refrigeration cycle diagram including an expansion valve according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a protruding member of FIG.

FIG. 3 is a sectional view showing a connection structure between an expansion valve and an evaporator in FIG. 1;

FIG. 4 is an explanatory diagram of an effect of the present invention.

FIG. 5 is a cross-sectional view of a main part of an expansion valve according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing a connection structure between an expansion valve and an evaporator according to a third embodiment of the present invention.

FIG. 7 is a sectional view of a main part of an expansion valve showing a fourth embodiment of the present invention.

[Explanation of Symbols] 4 ... Expansion valve, 5 ... Evaporator, 43 ... Low pressure side two-phase refrigerant passage,
43a: first passage, 43b: second passage, 47: valve body, 4
8: throttle passage hole, 60: projecting member, 60a: rigid member,
60b: buffer member, 70: block joint.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masanori Yasuda 14 Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Prefecture Inside the Japan Automobile Parts Research Institute (72) Inventor Noriaki Ando 14-Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Prefecture Inside the Japan Automobile Parts Research Institute (72) Inventor Fujio Nomura 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside Denso Corporation (72) Inventor Teruyuki Hotta 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside Denso (72) Inventor Hiroshi Hayashi 7-17-24 Todoroki, Setagaya-ku, Tokyo F-term in Fujikoki Co., Ltd. F-term (reference) 3H057 AA04 BB45 CC06 DD05 EE01 FB05 HH07 HH18 3H066 AA01 BA32 EA11 EA31

Claims (4)

[Claims] 1. A throttle passage hole (48) for reducing and expanding a high-pressure side liquid refrigerant, a valve body (47) displaced so as to adjust an opening area of the throttle passage hole (48), and the throttle passage hole. And a low-pressure two-phase refrigerant passage (43) for feeding the low-pressure two-phase refrigerant that has passed through (48) to the inlet (5a) of the evaporator (5). ) Are a first passage (43a) located on the throttle passage hole (48) side and a first passage (43) located on the refrigerant flow downstream side of the first passage (43a).
a) having a second passage (43b) having a larger passage cross-sectional area than that of the first passage (43b).
An expansion valve, characterized in that it is provided with a protruding member (60) that protrudes toward the front. 2. The projecting member (60) has a cylindrical shape and has a length from the throttle passage hole (48) to the projecting end face of the projecting member (60) in the low-pressure side two-phase refrigerant passage (43). The expansion valve according to claim 1, wherein the length (B) is at least 1.5 times the inner diameter (A) of the projecting member (60). 3. The protruding member (60) is connected to the low pressure side 2
Expansion valve body (41a) forming phase refrigerant passage (43)
3. The expansion valve according to claim 1, wherein the expansion valve is press-fitted from a downstream side of the refrigerant flow in the low-pressure two-phase refrigerant passage. 4. The projecting member (60) is formed of a rigid member (60a) having high rigidity and a shock absorbing cushioning member (60b) disposed on an inner surface of the rigid member (60a). 4. The method according to claim 1, wherein
The expansion valve according to any one of the above.