An accumulator has a tank and a desiccant. The tank separates refrigerant flowing to the tank into vapor-phase refrigerant and liquid-phase refrigerant, therein stores the liquid-phase refrigerant, and emits the vapor-phase refrigerant toward a suction side of a compressor. The desiccant is disposed in the tank and removing a water content from the refrigerant. Liquid-phase refrigerant included in the refrigerant flowing to the tank drops downward from a location that is located above the desiccant, and is stored in a lower portion in the tank. Vapor-phase refrigerant included in the refrigerant flowing to the tank is drawn through a suction port that is located above the desiccant to flow out of the tank. At least a part of the desiccant is exposed to vapor-phase refrigerant under a normal condition, and the desiccant is located at a location that is away from a dropping route of liquid-phase refrigerant in the tank.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C. 371 of International Application No. PCT/JP2013/004700 filed on Aug. 2, 2013 and published in Japanese as WO 2014/038127 A1 on Mar. 13, 2014. This application is based on and claims the benefit of priority from Japanese Patent Application No. 2012-197222 filed on Sep. 7, 2012. The entire disclosures of all of the above applications are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an accumulator for a refrigerant cycle.

BACKGROUND OF ART

An accumulator separates refrigerant into vapor-phase refrigerant and liquid-phase refrigerant and supplies the vapor-phase refrigerant to a compressor constituting a refrigerant cycle. The accumulator has a tank separating refrigerant that flows to the accumulator into vapor-phase refrigerant and liquid-phase refrigerant and therein storing the liquid-phase refrigerant. In the accumulator, as disclosed in Patent Documents 1 and 2, a desiccant is disposed in the tank to remove a water content from the refrigerant.

In the accumulator of Patent Document 1, the desiccant is located on a lower side in the tank, and the desiccant is entirely soaked in liquid-phase refrigerant.

In the accumulator of Patent Document 2, the desiccant is located above a highest liquid level of liquid-phase refrigerant such that the desiccant is not entirely soaked in liquid-phase refrigerant. In the accumulator, the desiccant is located at all area of the tank in cross section. The desiccant is located directly below a refrigerant inlet for vapor-liquid mixed refrigerant. Furthermore, a suction port for vapor-phase refrigerant is located above the desiccant.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: JP-2001-082814 A

Patent Document 2: JP-2009-180469 A

SUMMARY OF INVENTION

From studies conducted by inventors of the present disclosure, it was found that there is a possibility of causing an unusual noise in a startup of a compressor constituting a refrigerant cycle in a case where the desiccant is entirely soaked in liquid-phase refrigerant as described in Patent Document 1. The reason is that a sudden refrigerant boiling that begins at the desiccant is caused due to a decompression inside the tank in a startup of the compressor, and the tank vibrates since a pressure is caused in the tank due to the sudden refrigerant boiling.

On the other hand, there is no possibility of causing the above unusual noise in the startup of the compressor in a case where the desiccant is not entirely soaked in liquid-phase refrigerant as described in Patent Document 2. However, in such a case, since the desiccant is located in the dropping route of liquid-phase refrigerant flowing to the tank, liquid-phase refrigerant dropping in the tank may collide with the desiccant and bounce off. The liquid-phase refrigerant bouncing off may be drawn through the suction port for vapor-phase refrigerant, and the compressor may draw the liquid-phase refrigerant.

The present disclosure has been made in view of foregoing points, and it is an object of the present disclosure to provide an accumulator with which both of an unusual noise caused in a startup of a compressor and an inflow of liquid-phase refrigerant through a suction port for vapor-phase refrigerant, due to collision of liquid-phase refrigerant with a desiccant, can be restricted.

To achieve the above object, an accumulator of the present disclosure has a tank and a desiccant. The tank separates refrigerant flowing to the tank into vapor-phase refrigerant and liquid-phase refrigerant, therein stores the liquid-phase refrigerant, and emits the vapor-phase refrigerant toward a suction side of a compressor. The desiccant is disposed in the tank and removing a water content from the refrigerant. Liquid-phase refrigerant included in the refrigerant flowing to the tank drops downward from a location that is located above the desiccant, and is stored in a lower portion in the tank. Vapor-phase refrigerant included in the refrigerant flowing to the tank is drawn through a suction port that is located above the desiccant to flow out of the tank. At least a part of the desiccant is exposed to vapor-phase refrigerant under a normal condition, and the desiccant is located at a location that is away from a dropping route of liquid-phase refrigerant in the tank.

The inventors of the present disclosure studied remedies for the unusual noise in the startup of the compressor. From the studies, the inventors found that a cause of a vibration of tank in the startup of the compressor can be restricted, and a cause of the unusual noise can be restricted, by disposing the desiccant to be partially exposed outside of liquid-phase refrigerant and located inside of the vapor-phase refrigerant, not to be entirely soaked in liquid-phase refrigerant, in the startup of the compressor. Moreover, by disposing the desiccant not to be entirely soaked in liquid-phase refrigerant, a sudden refrigerant boiling that begins at the desiccant is not caused, and the cause of the unusual noise in the startup of the compressor can be restricted.

Therefore, according to the present disclosure, since the desiccant is not soaked partially or entirely in liquid-phase refrigerant in the startup of the compressor, the cause of the unusual noise in the startup of the compressor can be restricted.

Furthermore, according to the present disclosure, since the desiccant is located at a location that is away from the dropping route of liquid-phase refrigerant in the tank, liquid-phase refrigerant dropping in the dropping route can be prevented from colliding with the desiccant, and the inflow of liquid-phase refrigerant through the suction port for vapor-phase refrigerant can be restricted.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described hereafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference number.

First Embodiment

An accumulator of the present embodiment is used in a refrigerant cycle for a vehicle air conditioner. As shown inFIG. 1, the refrigerant cycle has a compressor1, a condenser3, a decompressor4, an evaporator5, and the accumulator10.

The compressor1draws and compresses refrigerant. The compressor1is rotatively driven by an engine (not shown) through a pulley2, a belt, or the like for traveling a vehicle.

A variable capacity compressor of which refrigerant discharge performance can be adjusted based on a variation of a discharge capacity or a fixed capacity compressor of which refrigerant discharge performance is adjusted by changing an operation rate of the fixed capacity compressor due to on-off of an electromagnetic clutch may be used as the compressor1. When an electric compressor is used as the compressor1, a refrigerant discharge performance can be adjusted by adjusting a rotation speed of an electric motor.

A vapor-phase refrigerant having a high pressure that is discharged from the compressor1flows into the condenser3. The vapor-phase refrigerant is cooled and condensed by exchanging heat with outside air in the condenser3. Subsequently, a liquid-phase refrigerant condensed in the condenser3is decompressed to have a low pressure in the decompressor4and turned into a vapor-liquid mixed mist. An orifice, a fixed throttle such as a nozzle, or an appropriate variable throttle configures the decompressor4.

Refrigerant having a low pressure after being decompressed is evaporated by absorbing heat from air that is blown by an un-shown blower for air conditioning. The evaporator5is disposed in an un-shown air conditioning case, and a cool air cooled in the evaporator5is blown into a passenger compartment after a temperature of the cool air is adjusted in an un-shown heater core part, as well known. Refrigerant passing through the evaporator5is drawn by the compressor1after being separated into vapor-phase refrigerant and liquid-phase refrigerant in the accumulator10.

The accumulator10exerts a roll to separate refrigerant flowing from the evaporator5into vapor-phase refrigerant and liquid-phase refrigerant, store the liquid-phase refrigerant, and supply the vapor-phase refrigerant to be drawn by the compressor1. The accumulator10also exerts a roll to supply oil that is merged with liquid-phase refrigerant stored at a bottom side in a tank to be drawn by the compressor1.

As shown inFIG. 2, the accumulator10has a tank11a tank11separating refrigerant flowing to the tank into vapor-phase refrigerant and liquid-phase refrigerant. The tank11therein stores the liquid-phase refrigerant and emits the vapor-phase refrigerant toward a suction side of a compressor. An arrow showing an upper-lower direction inFIG. 2shows a vertical direction with the accumulator10that is under a condition of being disposed in the vehicle.

The tank11is provided with a tank body12and a header13sealing an upper end portion of the tank body12. The tank body12and the header13is made of metal, and the upper end portion of the tank body12and the header13are fixed to each other by brazing.

The tank body12has a bottomed cylindrical shape in which the upper end portion is open. The tank body12therein houses a chuting member14, a suction pipe15, and a desiccant16. A separated liquid-phase refrigerant is stored in a lower portion in the tank body12, and a lubricating oil is stored in the lower portion in the tank body12in a state of merging with the liquid-phase refrigerant.

The header13is formed in a flat tubular shape of which diameter is the same as a diameter of the tank body12. The header13has a refrigerant inlet131and a refrigerant outlet132opening in the upper-lower direction and having a circular shape. The refrigerant inlet131communicates with the evaporator5through a pipe such that refrigerant after exchanging heat in the evaporator5can flow into the tank body12. The refrigerant outlet132communicates with the compressor1through a pipe such that vapor-phase refrigerant after being separated in the tank body12can outflow toward the compressor1.

The chuting member14is a colliding member with which refrigerant introduced from the refrigerant inlet131to flow downward in a vertical direction collides. The chuting member14has a sidewall141that extends in the upper-lower direction and has a cylindrical shape and an upper wall142that seals an upper end side of the sidewall141. A lower end side of the sidewall141is open.

The chuting member14is disposed on an upper area in the tank11such that the upper wall142is visible when viewing the tank body12from the refrigerant inlet131. A portion of the upper wall142that faces the refrigerant inlet131protrudes upward, and a portion of the upper wall142that faces the refrigerant outlet132is provided with an opening. The chuting member13is made of metal and press-fitted to a bottom surface of the header13in a state that the opening provided at the upper wall142coincides with the refrigerant outlet132. An outer periphery of the upper wall142is located close to an inner wall of the tank body12.

The accumulator10of the present embodiment is a collision type accumulator in which refrigerant introduced from the refrigerant inlet131is separated into liquid-phase refrigerant and vapor-phase refrigerant after colliding with the chuting member14. That is, refrigerant colliding with the upper wall142of the chuting member14spreads in a lateral direction of the tank11, and then, the refrigerant is introduced to an outer side of the outer periphery of the chuting member14in the lateral direction of the tank11. The liquid-phase refrigerant drops from the outer side of the outer periphery of the chuting member14, flows along the inner wall of the tank body12, and is accumulated in a lower area in the tank body12. The vapor-phase refrigerant is drawn into the suction pipe15from a lower side of the chuting member14and flows out of the tank11.

According to the present embodiment, the suction pipe15is a double pipe type and has an inner pipe151and an outer pipe152. Both of the inner pipe151and the outer pipe152are made of a straight pipe and housed in the tank body12in an upright position. The inner pipe151is located in the outer pipe152such that the inner pipe151and the outer pipe152are coaxial with each other.

The inner pipe151is fixed to the bottom surface of the header13. Specifically, the inner pipe151is made of metal and press-fitted to the bottom surface of the header13in a state that an opening of an upper end portion of the inner pipe151coincides with the refrigerant outlet132.

The outer pipe152is fixed to the inner pipe151. Specifically, the outer pipe152is made of plastic, and an inner wall of the outer pipe is provided with an un-shown protruding portion (i.e., a thick portion). The outer pipe152is press-fitted by inserting the inner pipe151to an inside of the protruding portion.

The outer pipe152is in a state that an upper end opening153providing a suction port for vapor-phase refrigerant is located inside of the chuting member14, and the chuting member14and the upper wall142are a specified distance away from each other.

In the outer pipe152, a lower end portion154is sealed, and an oil return hole155is formed at a bottom of the lower end portion154. The oil return hole155draws the lubricating oil stored in the lower area in the tank body12due to vapor-phase refrigerant flowing to the inner pipe151such that the lubricating oil passes through the inner pipe151with the vapor-phase refrigerant.

A filter cap156is attached to an outside of the lower end portion154of the outer pipe152. The filter cap156is formed in a bottomed cylindrical shape, and a filter157removing a sludge or the like included in the oil is disposed on a cylindrical sidewall of the filter cap156.

A retainer158supporting the desiccant16is located close to a center of the outer pipe152in the upper-lower direction. The retainer158is made of plastic and formed integrally with the outer pipe152. As shown inFIG. 3, the retainer158is formed in a shape having beams that extend from the outer pipe152in the lateral direction of the tank. The retainer158may be provided separately from the outer pipe152.

The desiccant16removes a water content from refrigerant. As shown inFIG. 3, the desiccant16is a particle such as zeolite and used in a state of being housed in a sack161. The sack161is a desiccant case that is made of fabric such as felt, has flexibility, and works as a filter.

The sack161in which the desiccant16is housed is fixed in a manner that the sack161is tied by a fixing part162formed in a band shape such as a banding band, in a state of being wound around the suction pipe15.

In such a state, the desiccant16is located on an inner side of the outer periphery of the chuting member14in the lateral direction of the tank11and not located on an outer side of the outer periphery of the chuting member14. In other words, the desiccant16is located in an area that is directly below the chuting member14and at a location that is longer than or equal to a specified distance away from the inner wall of the tank11. The specified distance is a distance Y1between the chuting member14and the inner wall of the tank11.

The desiccant16is disposed such that an upper end of the desiccant16is located below the suction port153of the outer pipe152not to interfere the suction port153. The upper end of the desiccant16is located above a liquid level (i.e., a highest liquid level) Lmax that is a liquid level when a largest amount of liquid-phase refrigerant is stored in the tank11. That is, a part of the desiccant16is constantly is exposed to vapor-phase refrigerant.

The highest liquid level mentioned here is a highest liquid level under a condition that the compressor1is stopped. The highest liquid level is determined based on a sealed-in amount of refrigerant sealed in a whole of the refrigerant cycle. Although the sealed-in amount of refrigerant increases due to a size of the refrigerant cycle, a maximum sealed-in amount is about 1,000 g in practical use, and a liquid level is determined to be about 150 mm in the tank11that is used in the studies conducted by the inventors of the present disclosure. Therefore, in this case, the desiccant16is disposed such that the upper end of the desiccant16is located between the suction port153and a location of which height from a bottom surface of the tank11is 150 mm.

In the accumulator10having the above structure, refrigerant flowing out of the evaporator5flows into the tank body12through the refrigerant inlet131. Refrigerant flowing to the tank body12is separated into liquid-phase refrigerant and vapor-phase refrigerant by being guided to the inner wall of the tank body12due to the chuting member14. The separated liquid-phase refrigerant congregates in the lower area in the tank body12, and vapor-phase refrigerant flows out of the outer pipe152toward the compressor1through the inner pipe151.

When the vapor-phase refrigerant flows out of the outer pipe152and flows into the inner pipe151, the lubricating oil stored in the lower area in the tank12is drawn through the filter157and the oil return hole155and outflows with the vapor-phase refrigerant from the refrigerant outlet132toward the compressor1through the inner pipe151.

In the following portion, effects of the present embodiment will be described.

(1) In the present embodiment, the desiccant16is disposed such that a part of the desiccant16is located above the highest liquid level Lmax that is determined under the condition that the compressor1is stopped. Thus, according to the present embodiment, a cause of a vibration of the tank11in a startup of the compressor1can be restricted, and a cause of an unusual noise can be restricted, as shown in experimental results ofFIG. 4.

The experimental results ofFIG. 4are experimental results regarding the accumulator10of the present embodiment and a comparison example. The experimental results are results of measurement of the vibration of the tank11in the startup of the compressor11while varying the liquid level in the tank11under the condition that the compressor1is stopped by changing the sealed-in amount of refrigerant sealed in the refrigerant cycle. An operation condition of the refrigerant cycle is fixed. A vertical axis inFIG. 4shows the vibration of the tank. A horizontal axis inFIG. 4shows the liquid level in the tank11, and the liquid level increases as shifting rightward from L1through Lmax inFIG. 4. Lmax is the highest liquid level.

As shown inFIG. 5, in the accumulator of the comparison example, the desiccant16is located in a lower area in the tank11.

As shown inFIG. 4, in the comparison example, when the liquid level was between L1through L3, a part of the desiccant was located outside of the liquid-phase refrigerant, and the vibration was not caused. However, when the liquid level was between L4through Lmax, the desiccant was entirely soaked in liquid-phase refrigerant, and the vibration was caused.

On the other hand, according to the present embodiment, the desiccant was entirely soaked in liquid-phase refrigerant when the liquid level is at L3, a part of the desiccant was located outside of liquid-phase refrigerant when the liquid level was between L4through Lmax, and the vibration was not caused at any liquid level.

(2) In the present embodiment, the desiccant16is located at a location that is at least a specified distance away from the inner wall of the tank11. That is, the desiccant16is located at a location that is away from a dropping route along which liquid-phase refrigerant drops from the outer side of the outer periphery of the chuting member14.

Therefore, liquid-phase refrigerant dropping from the outer side of the outer periphery of the chuting member14is prevented from colliding with the desiccant16, and liquid-phase refrigerant can be prevented from being drawn through the suction port153of the outer pipe152.

(3) According to the present embodiment, the desiccant16is housed in the sack161and fixed by the fixing part162in a state that the sack161is wound around the suction pipe15.

Therefore, similar to the above comparison example, when the present disclosure is used in a conventional accumulator in which the sack161housing the desiccant16is located in the lower area in the tank11, only a location and a fixing method of the sack161are required to be changed, and a design change of components of the accumulator is unnecessary.

Furthermore, when the present disclosure is used in a conventional accumulator in which the desiccant16is housed in a container except for the sack161, a design change of components of the accumulator is unnecessary except for using the sack161.

Second Embodiment

In the present embodiment, a case for the desiccant16is changed as compared to the first embodiment, and other constitutions are the same as that of the first embodiment.

As shown inFIGS. 6 and 7, the desiccant16is filled in a case163made of plastic and fixed to the outer pipe152at a lower part that is below the suction port153.

The case163is located at a location that is at least the specified distance away from the inner wall of the tank11, similar to the first embodiment. That is, the case163is located at a location that is away from the dropping route along which refrigerant drops from the outer side of the outer periphery of the chuting member14.

As shown inFIG. 7, the case163has a cross sectional shape that occupies most part of a cross section of the tank11as being away from a nearby area of the inner wall of the tank in which liquid-phase refrigerant drops. By forming the case163in the above shape, a volume of the case can increase, and a using amount of the desiccant16can increase.

Here, in a case that a desiccant case has flexibility, the desiccant case is deformed due to a weight of the desiccant, and a bias of the desiccant causes.

Then, the case163of the present embodiment is made of plastic and relatively hard. Accordingly, the case163can be kept in a specified shape. Therefore, according to the present embodiment, since the case163is not deformed due to the weight of the desiccant16, the desiccant16filled in the case163can be prevented from being biased. A case made of a material except for plastic may be used as the case163as long as the case can be kept in a specified shape.

Moreover, as shown inFIG. 7, the case163has a press-fitting portion164formed in a shape that fits an outer peripheral surface of the suction pipe15, and the suction pipe15is fixed by being press-fitted to the press-fitting portion164. The press-fitting portion164has a C-shape corresponding to the suction pipe15in a circumference direction except for a part of the suction pipe15. The suction pipe15is press-fitted to the press-fitting portion164by pressing the press-fitting portion164against the suction pipe15in the lateral direction.

Thus, by employing a constitution in which the case163made of plastic is press-fitted to the suction pipe15, only the case163having the above shape is required to be further disposed, and other components, except for the case163, consisting the accumulator can employ conventional components. Furthermore, an assembly process of the desiccant16to the suction pipe15become easier with a manner of fixing the case163by press-fitting as compared to with a manner of fixing the case by tying the sack161.

Although the press-fitting portion164has the C-shape as described above, the press-fitting portion164may have an O-shape. In such a case, the case163is fixed to the suction pipe15by inserting the suction pipe15to the press-fitting portion164having the O-shape.

Third Embodiment

In the present embodiment, a suction pipe is changed as compared to the first embodiment. That is, in the present embodiment, a U-shaped pipe159is used as the suction pipe. The desiccant16is housed in the sack161similar to the first embodiment, and the sack161is fixed by the fixing part162in a state of being wound around the U-shaped pipe159. Thus, the present disclosure can be used in a case using the U-shaped pipe159as the suction pipe.

The case163made of plastic may be used as the case of the desiccant16similar to the second embodiment.

Other Modification

The present disclosure is not limited to the above embodiments, and the embodiments can be modified as needed within a scope of the present disclosure.

(1) In the first embodiment, the fixing part162having band like shape is wound all around the sack161in a circumference direction of the sack161in a state that the sack161housing the desiccant16is wound around the suction pipe15. However, the sack161may be fixed by another fixing part. For example, the sack161may be fixed to the suction pipe15in a manner that end portions of the sack161wound around the suction pipe15are seamed to each other or that a ring-shaped fixing part is inserted to an opening provided at an end portion of the sack161.

(2) Although the case163for the desiccant16is press-fitted to the suction pipe15in the second embodiment, the case163may be fixed by another method except for press-fitting. For example, the case163for the desiccant16are formed integrally with the outer pipe152of the suction pipe15. In this case, a cap of the case163is formed separately.

(3) The case163for the desiccant16has the shape shown inFIGS. 6 and 7in the second embodiment. However, the case163may have another shape as long as the desiccant16is located on the inner side of the outer periphery of the chuting member14in the lateral direction of the tank11.

(4) Although the chuting member14has the shape shown inFIG. 2in the above embodiments, the chuting member14may be varied to have another shape.

(5) In the above embodiments, the chuting member14may be omitted. In this case, since liquid-phase refrigerant drops from the refrigerant inlet131, the refrigerant inlet131becomes a starting position from which the liquid-phase refrigerant drops. Then, in this case, the desiccant16may be located avoiding a location that is directly below the refrigerant inlet131.

(6) In the above embodiments, a part of the desiccant16is located above the highest liquid level Lmax that is determined under the condition that the compressor1is stopped. However, a whole of the desiccant16may be located above the highest liquid level Lmax.

It should be understood that components consisting the above embodiments are not necessary except for a case that the components are explicitly mentioned to be necessary or a case that the components are considered to be explicitly necessary in principle. Furthermore, the above embodiments are not irrelevant to each other and can be combined as needed except for a case that a combination is explicitly unacceptable.