JPH025335Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Industrial Field of Application) The present invention relates to an anti-freezing device for a flexible hose of an automobile air conditioner that uses a flexible hose for piping of a cooling circuit.

(Prior Art) As shown in FIG. 1, an air conditioner for an automobile includes an intake unit 1, a cooler unit 2,
It has a heater unit 3. The intake unit 1 has a fan 5 driven by a motor 4.
is built-in, and further provided with an inside air inlet 6 through which the circulation flow into the vehicle interior flows and an outside air intake 7 through which outside air flows. An intake door 9 is installed within the intake unit to switch and control air flowing into the intake unit 1 through the inside air inlet 6 and air flowing through the outside air intake 7. The intake door 9 moves to a position A where the inside air inlet 6 is closed, a position C where the outside air intake 7 is closed, and a position B between these positions.

The cooler unit 2 into which air from the intake unit 1 flows has a built-in evaporator 12 in which refrigerant is circulated through a refrigerant conduit 11.
Intake unit 1 inside this cooler unit 2
After the air introduced from the heater unit 3 is cooled,
flow inside.

Inside this heater unit 3 is a cooler unit 2.
A heater core 16 is installed into which engine cooling water is introduced via a conduit 15 in order to heat the air passing through it. A mixer door 17 is attached to the front surface of the heater core 16, and by setting the mixer door 17 to any position between the F position and the D position (for example, the E position), the air that has passed through the cooler unit 2 is directed away from the heater core 16. The air may be sent into the passenger compartment from the rear of the heater unit 3 without being heated at all, or all of the air may be passed through the heater core 16 and heated before being sent into the passenger compartment, or some of the air from the cooler unit 2 may be passed through the heater core 16. ,
Other air is passed through the mixture passage, avoiding the heater core, and is mixed with the other air, making air at an appropriate temperature and sending it into the passenger compartment.

The heater unit 3 includes a defrost duct 19 for blowing air along the inner surface of the windshield, a floor duct 20 for blowing air toward the passenger's feet in the passenger compartment R, and an instrument panel vent. From air outlet 10 to vehicle compartment R
A vent duct 21 for blowing air inward is provided, and a defrost duct 1 is also provided.
A room door 22 for controlling air distribution between the floor duct 9 and the floor duct 20, and a vent door 23 for controlling air distribution flowing to the vent duct 21 are provided.

The cooling circuit of such an automobile air conditioner includes a compressor 24 on the engine room ER side,
A condenser 25 and a liquid tank 26 are connected to each other via a refrigerant conduit 11, and a refrigerant expansion member 27 is provided in addition to the evaporator 12 on the inside of the vehicle compartment.

The refrigerant expansion member 27 generally includes a thermostatic automatic expansion valve and a capillary tube type, but when these are used, the following drawbacks occur.

Because the thermostatic expansion valve attempts to maintain a constant degree of superheat over a wide range of loads and variations in compressor 24 capacity, large changes in compressor 24 capacity due to changes in engine speed result in changes in the cooling cycle. This results in a pressure change in the low pressure line. Therefore, when the vehicle is running at high speed, even when the heat load is not so low, the pressure in the low pressure line decreases and the evaporator 12 freezes. To prevent this, conventional methods have been adopted, such as turning the compressor 24 on and off using a thermostat, or installing an evaporation pressure control valve at the outlet of the evaporator 12. In addition, fluctuations in the vehicle's power due to ON/OFF of the compressor 24 are unpleasant for the vehicle driver. In addition, the latter has an evaporation pressure control valve that expands and controls the vaporized refrigerant in a large passage, and pressure loss during high heat loads cannot be tolerated, so it is inevitable that it will be larger and more sophisticated. Since it is an expansion valve, the entire device is expensive.

Although capillary reach tubes have a range of capacity balancing functions and are less expensive because they do not use thermostatic automatic expansion valves, they still suffer from the problem of evaporator freezing. In other words, if the capillary is designed for high-speed driving, the chance of freezing will be relatively reduced, but the cooling capacity will be poor during low-speed driving, and if the capillary is designed for low-speed driving, the pressure in the low-pressure line will decrease during high-speed driving. This increases the chance of freezing. Therefore, even if a capillary reach tube is used, in order to completely prevent freezing accidents, the compressor 24 must be controlled by a thermostat.
It becomes necessary to turn it on and off, or to install an evaporation pressure control valve, and the choice has to be made between operational discomfort and high equipment costs. A further drawback of the capillary reach tube system is that even if the operation of the cooling system is stopped, the flow of refrigerant does not stop as long as there is a pressure difference or a temperature difference between the condenser 25 and the evaporator. For this reason,
In extremely hot regions, the sound of refrigerant passing through the capillary may be audible when the vehicle is stopped, and the flow of refrigerant due to the difference in temperature between the inside and outside air while the vehicle is parked may cause the refrigerating machine oil in the compressor to gradually leak into the evaporator, etc. They tend to collect in low-lying areas, which can cause trouble starting after long-term parking.

In addition, in the automobile air conditioner configured as described above, the compressor 24
may rotate even in cold winter weather. In such a case, no matter which one of the above-mentioned refrigerant expansion members 27 is used, freezing of the evaporator 12 or the refrigerant pipe on the low pressure side is likely to occur.

On the other hand, modern automobiles have good sound insulation inside the cabin, so occupants are sensitive to even the slightest sound. Therefore, the evaporator 12 and the compressor 24 are connected, and the compressor 24 and the condenser 25 are connected so that the vibrations of the engine E and the noise from the compressor 24 itself and the cooling circuit, especially vibration noise, are not transmitted into the passenger compartment. The refrigerant conduit is constituted by a flexible hose made of elastic material.

(Problem to be solved by the invention) In such a car air conditioner,
If the compressor 24 is operated in a cold region when the outside temperature is negative, the flexible hose may freeze and harden, and vibrations from the engine E and the compressor 24 may be transmitted through the freeze-hardened flexible hose and cause vibration noise to be transmitted into the passenger compartment. .

The present invention was developed in view of these problems, and is an antifreeze device for flexible hoses that bypasses high-temperature refrigerant when necessary to prevent the flexible hose from freezing and hardening regardless of the outside temperature. The purpose is to provide

[Structure of the invention] (Means for solving the problem) The present invention for achieving the above object has a low pressure chamber that communicates with the evaporator side and a high pressure chamber that communicates with the condenser side, which are formed in the casing. The chamber is partitioned by a partition wall, and the refrigerant expansion member is arranged such that the opening degree of a flow path opened in the partition wall is adjusted by a main valve member provided on the high pressure chamber side, and at least the compressor and the evaporator are connected to each other. In a cooling circuit for an automobile air conditioner in which a communicating refrigerant conduit is constructed of a flexible hose, a bypass passage having a smaller diameter than the flow passage is opened in the partition wall, and an auxiliary valve member for opening and closing the bypass passage is set at the low pressure. The sub-valve member is provided on the chamber side, and opens when the main valve member closes or almost closes the flow path and the pressure in the high-pressure chamber exceeds a predetermined value, and the high-temperature refrigerant corresponding to this pressure is opened. This is a device for preventing freezing of a flexible hose, characterized in that the flexible hose is biased by a spring so as to guide the flexible hose to the flexible hose.

(Function) By doing this, when the outside temperature is low, that is, when there is no need to flow a large amount of refrigerant, the high-temperature refrigerant in the high-pressure chamber is guided to the flexible hose through the bypass passage. freeze-hardening is prevented, and vibrations and noise from the compressor, etc., are prevented from propagating into the passenger compartment.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

FIG. 2 shows an example of the antifreeze device for a flexible hose according to the present invention, and the same members as those shown in FIG. 1 are given the same reference numerals.

The cooling circuit 30 includes a compressor 24, a condenser 25, a liquid tank 26, a refrigerant expansion member 27, and an evaporator 12 connected by a refrigerant conduit 11. Some of the refrigerant conduits 11 outside the vehicle interior connect the compressor 24 and the evaporator 12, and the compressor 24 and the condenser 25, and these refrigerant conduits are constituted by flexible hoses 31 and 32. This point is similar to the conventional one.

Note that "a" in the figure is a pressure equalizing pipe communicating with the outlet side of the evaporator 12.

Of these two flexible hoses 31 and 32, the one that connects the compressor 24 and condenser 25 has a high temperature refrigerant flowing inside it even when the compressor 24 is operating, so even if the outside temperature is below 0°C. Does not freeze harden. Therefore, the antifreeze device 33 may be provided on the flexible hose 31 side that connects the compressor 24 and the evaporator 12.

Freeze prevention device 33 for this flexible hose
As shown in FIG. 3, this refrigerant expansion member 27 is an improved version of the refrigerant expansion member 27. The refrigerant expansion member 27 has a high pressure chamber 38 in the casing 34 that communicates with the condenser 25 side, and a high pressure chamber 38 that communicates with the evaporator 12 side. It has a low-pressure chamber 39 with a low pressure chamber 39 and a partition wall A that partitions both chambers 38 and 39, and a flow path 40 is opened in this partition wall A, and the opening degree of the flow path 40 is set on the high-pressure chamber side. A main valve member 35 is provided for adjustment.
Please note that this partition wall A is made of casing 3 due to production reasons.
4 is press-fitted and fixed.

Further, in the vicinity of the flow path 40, this flow path 40
A bypass passage 36 having a smaller diameter is provided, and an auxiliary valve member 37 is attached to the low pressure chamber side of this bypass passage 36.

The main valve member 35 is pressed upward by a pressing member 42 which is resiliently repelled by a spring 41, and its valve stem 43 is inserted into and extends within the low pressure chamber 39, and its upper end is applied to a diaphragm 44 by the resilient force of the spring 41. are in contact with each other. A temperature-sensitive medium 46 is sealed in the closed space formed by the diaphragm 44 and the lid 45, and a conduit 47 attached to the lid 45 comes into contact with the outlet pipe of the evaporator 12 to detect the temperature of the refrigerant. I try to do that. That is, the pressure of the temperature-sensitive medium 46 is determined in accordance with this refrigerant temperature, and the diaphragm 44 is operated to open and close the main valve member 35 via the valve rod 43, thereby controlling the amount of refrigerant flowing into the evaporator 12. There is.

On the other hand, the sub-valve member 37 has a valve stem 48,
This valve stem 48 is slidably attached to a support rod 49 whose one end is fixed to the valve stem 43. A coil spring 50 is interposed between the support rod 49 and the auxiliary valve member 37.
When the main valve member 35 is closed or close to closed and the pressure of the refrigerant in the high pressure chamber 38 exceeds a predetermined value, it is opened against the spring pressure of the coil spring 50. That is, as the main valve member 35 closes, the bypass passage 3
A force represented by the product of the cross-sectional area of 6 and the pressure inside the high pressure chamber 38 acts, and the spring force of the coil spring 50 is set to oppose this force.

For example, in a car air conditioner during normal cooling operation, the pressure in the high pressure chamber 38 is:
It is about 10 to 15 kg/cm ² , and the main valve member 35 is open. At this time, the sub-valve member 37 is closed against the pressure of the high-pressure chamber 38 due to the elastic force of the spring 50.

When the outside air reaches, for example, about 0°C, the pressure in the high pressure chamber 38 during operation becomes 10 kg/cm ² G or less, so the main valve member 35 is almost closed or close to it, and conversely, the auxiliary valve member 35 is closed or close to it. 36, the valve load is reduced by the expansion of the spring 50, and the valve opens against the pressure in the high pressure chamber 38.

Therefore, in order not to interfere with normal driving,
The diameter of the bypass passage 36 of this sub-valve member 37 is
Considering that the diameter of the main valve member 35 is about 2 to 3 mm, it is desirable to set it to about 0.5 to 1 mm.
The pressure in the high pressure chamber when the sub valve member 37 is opened is 10 kg/
cm ² G or less, for example, 5 kg/cm ² G, the elastic force of the spring 50 may be 0.1 to 0.2 kg.

In addition, in the figure, "51" is an E-ring, and "52" is an O-ring.
The ring ``53'' is a presser foot, and ``54'' is a ring that holds the presser foot fixedly.

Next, the effect will be explained.

Assume that an air conditioner for an automobile is operated in winter when the outside temperature is 0° C. or lower.

At the beginning of this startup, the flexible hoses 31, 3
No. 2 does not freeze harden much, but as the operation continues for a long time, freeze hardening gradually starts.

When the outside temperature is low enough to cause freeze-hardening (for example, 0° C.), there is not much need for cooling capacity, so the refrigerant in the high-pressure chamber 8 is guided to the low-pressure chamber 39 through the bypass passage 36. There is no problem. In other words, when the outside temperature is low, there is no need to flow a large amount of refrigerant, so the main valve member 35 closes.
At that time, the sub-valve member 37 opens, and the high-temperature refrigerant enters the low-pressure chamber 39 through the bypass passage 36 and flows into the flexible hose 31 via the evaporator 12 etc., heating the flexible hose 31. , which will prevent freeze-hardening.

On the other hand, when the automotive air conditioner performs normal cooling operation, since the outside temperature is high, the main valve member 3
5 is opened to allow a large amount of refrigerant to flow. This causes the valve stem 43 to move downward, so this valve stem 4
The support rod 49 of the sub-valve member 37 attached to the valve member 3 also moves downward, the elastic force of the coil spring 50 becomes even stronger, and the bypass passage 36 is reliably closed.

Therefore, even if this sub-valve member 37 is provided, there is no risk of interfering with normal cooling operation. In particular, the pressing force of the coil spring 50 fluctuates somewhat because the support rod 49 moves up and down as the main valve member 35 and valve rod 43 move up and down. There is no problem because the pressing force decreases when the air conditioner is not in use) and increases when the air conditioner is lowered (when cooling is required).

[Effects of the invention] As described above, according to the invention, even when the compressor is driven when the outside temperature is low and there is a risk that the flexible hose on the low pressure side may freeze and harden,
Since the high-temperature refrigerant flows from the high-pressure side to the low-pressure side of the cooling circuit, freezing and solidification of the flexible hose can be prevented, and vibration noise from the engine and compressor will not be transmitted into the passenger compartment.

Moreover, when this high-temperature refrigerant returns to the compressor, the compressor sucks in the high-pressure refrigerant, which reduces the power load, resulting in so-called energy savings.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of an air conditioner for an automobile, FIG. 2 is a schematic explanatory diagram showing an embodiment of the present invention, and FIG. 3 is a sectional view showing a main part of the embodiment. 12...Evaporator, 24...Compressor, 27...Cooling expansion member, 31...Flexible hose, 33...Flexible hose antifreeze device, 35...Main valve member, 36...Bypass passage, 37...Sub-valve Member, 38... High pressure chamber, 39...
...Low pressure chamber, 40...Flow path, 43...Valve stem, 44...
...Diaphragm, 47...Detection conduit, 48...Valve rod, 49...Support rod, 50...Spring, A...Partition wall.

Claims (1)

[Scope of utility model registration request] A low pressure chamber 39 communicating with the evaporator 12 side and a high pressure chamber 38 communicating with the condenser 25 side are formed in the casing 34, and these chambers are partitioned by a partition wall A, and a flow path 40 opened in the partition wall A is opened. The main valve member 35 provided on the high pressure chamber 38 side
In the cooling circuit of an air conditioner for an automobile, the refrigerant expansion member 27 is adjusted by the partition wall A, and the refrigerant conduit 11 communicating with at least the compressor 24 and the evaporator 12 is formed of a flexible hose. A small-diameter bypass passage 34 is opened by the flow path 40, and a sub-valve member 37 for opening and closing this bypass passage 36 is provided on the low-pressure chamber 39 side. When the flow path 40 is closed or almost closed and the pressure in the high pressure chamber 38 exceeds a predetermined value, the valve opens and is biased by a spring 50 so as to guide a high temperature refrigerant corresponding to this pressure to the flexible hose. A flexible hose antifreeze device featuring: