JP2002195695A - solenoid valve - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent refrigerant from entering an evaporator on the rear side from its outlet and accumulating therein when air conditioning is performed only on the front side. SOLUTION: An electromagnetic valve 8 is provided between a rear side evaporator and an expansion valve.
The electromagnetic valve 8 is connected to the low-pressure refrigerant passage hole 11 by the electromagnetic solenoid 20 in the middle of the low-pressure refrigerant passage hole 11 for sending the refrigerant adiabatically expanded from the expansion valve to the refrigerant inlet pipe of the rear evaporator. A valve body 15 for closing / opening the valve 11;
A one-way valve 30 provided in the middle of the low-pressure refrigerant passage hole 12 for sending the refrigerant sent from the refrigerant outlet pipe of the rear evaporator to the expansion valve. When the rear evaporator is not used, the electromagnetic solenoid 20 is de-energized to close the low-pressure refrigerant passage holes 11 and 12 so that the refrigerant does not enter the rear evaporator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve, and more particularly to an electromagnetic valve for an automobile having an evaporator on each of a front side and a rear side of an automobile. The present invention relates to an electromagnetic valve interposed between an expansion valve for controlling a flow rate of a refrigerant to be sent.

[0002]

2. Description of the Related Art Some air conditioners for automobiles can separately control the temperature of a room on a front side and a rear side. In such an automotive air conditioner, an evaporator as an indoor heat exchanger is provided on each of a front side and a rear side. These evaporators are connected in parallel in the refrigeration cycle, and by adjusting the amount of refrigerant flowing through these evaporators, it is possible to adjust the temperature of the indoor air that is heat-exchanged in each evaporator.

An expansion valve adjusts the flow rate of the refrigerant sent to the evaporator. The expansion valve is generally driven by a power element that operates by sensing changes in the temperature and pressure of the low-pressure refrigerant sent from the outlet of the evaporator through heat exchange with room air, and the flow rate of the refrigerant sent to the evaporator. Is controlling.

Here, when air conditioning is performed only on the front side and air conditioning on the rear side is not performed, the refrigerant may be flown only into the evaporator on the front side so that the refrigerant does not flow into the evaporator on the rear side. . As an expansion valve having a function of stopping the flow of the refrigerant on the rear side, Japanese Patent Laid-Open No.
An expansion valve with an electromagnetic valve described in Japanese Patent No. 325659 is known.

The expansion valve with the electromagnetic valve is provided in the rear evaporator so that the low-pressure refrigerant flow path between the expansion valve and the inlet of the evaporator can be forcibly closed by the electromagnetic valve. I have to. Thus, when air conditioning on the rear side is not required, the solenoid valve closes the low-pressure refrigerant flow path so that the refrigerant does not flow into the evaporator.

[0006]

However, when air conditioning is performed only on the front side, the refrigerant does not flow into the rear side evaporator by closing the inlet of the rear side evaporator with an electromagnetic valve. If only the front side evaporator is used, the refrigerant flowing out of the outlet of the front side evaporator flows back to the outlet of the rear side evaporator and enters the rear side evaporator, and the There is a problem that the cooling power is insufficient due to a reduction in the amount of refrigerant circulating in the refrigeration cycle on the front side due to accumulation in the evaporator on the side.

The present invention has been made in view of such a point, and is provided between an expansion valve and an evaporator. When air conditioning is performed only on the front side, the outlet of the evaporator on the rear side is provided. It is an object of the present invention to provide an electromagnetic valve capable of preventing a refrigerant from entering from below.

[0008]

According to the present invention, in order to solve the above-mentioned problem, a refrigerant is interposed between an expansion valve and an evaporator to supply a refrigerant from the expansion valve to a refrigerant inlet pipe of the evaporator. A solenoid valve that closes / opens a valve element provided in a first refrigerant flow path for performing a refrigerant flow from a refrigerant outlet pipe of the evaporator to the expansion valve. An electromagnetic valve is provided, which is provided with a one-way valve provided in a refrigerant flow passage and allowing a flow of the refrigerant only in a direction from the evaporator to the expansion valve.

If such a solenoid valve is applied between the rear expansion valve and the evaporator, when air conditioning on the rear side is performed, the valve element provided in the first refrigerant flow path is fully opened. Controlled,
The one-way valve provided in the second refrigerant flow path is also opened by the supply pressure of the refrigerant sent from the evaporator, so that the refrigerant can flow from the expansion valve to the evaporator and from the evaporator to the expansion valve. When air conditioning on the rear side is not performed, the valve element provided in the first refrigerant flow path is controlled to a fully closed state, and the first refrigerant flow path to the evaporator is closed. Because the first refrigerant flow path is closed, the one-way valve provided in the second refrigerant flow path does not send out the refrigerant from the evaporator. Maintain the closed state. As a result, both the outlet and the inlet of the evaporator are closed, so that when the air conditioning on the rear side is not performed, the refrigerant does not enter the evaporator and accumulate in a liquid state. It does not occur that the amount of circulating refrigerant in the inside decreases and the cooling power becomes insufficient.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a system diagram of a vehicle air conditioner showing a refrigeration cycle to which a solenoid valve according to the present invention is applied.

The refrigeration cycle of the automotive air conditioner includes a compressor 1 for compressing a refrigerant, a condenser 2 connected to a discharge side of the compressor 1 for cooling and condensing a high-temperature and high-pressure refrigerant.
A liquid receiver 3 is connected downstream of the condenser 2 to separate gas and liquid from the condensed refrigerant and store the liquid refrigerant. The outlet side of the receiver 3 is divided into two, one is an expansion valve 4 that adiabatically expands the liquid refrigerant supplied from the receiver 3 to a low-temperature and low-pressure refrigerant, and the other is supplied from the expansion valve 4. Is connected to the suction side of the compressor 1 via a front side evaporator 5 for exchanging heat between the supplied refrigerant and room air.
It is configured to join the downstream side of the front-side evaporator 5 via the expansion valve 6 and the rear-side evaporator 7, and between the expansion valve 6 and the rear-side evaporator 7, an electromagnetic valve according to the present invention is provided. 8
Are interposed.

Here, for example, when air-conditioning is performed on the front side and the rear side at the same time, it is necessary to set the flow rate of the refrigerant to an appropriate flow rate so that the flow of the refrigerant does not compete between the front side and the rear side. Generally, when simultaneous air conditioning is performed on the front side and the rear side, the flow rate of the refrigerant is set so that air conditioning is preferentially performed on the front side.

The solenoid valve 8 according to the present invention has a function of closing a low-pressure refrigerant passage leading from the expansion valve 6 to the inlet of the rear evaporator 7 and a function of closing the low pressure refrigerant passage from the outlet of the front evaporator 5 to the outlet of the rear evaporator 7. A check function for restricting the flow of the refrigerant.

Thus, the solenoid valve 8 allows the refrigerant supplied from the expansion valve 6 to flow into the inlet of the rear evaporator 7 and to flow out of the outlet through the rear evaporator 7 when performing air conditioning on the rear side. When the rear side is not air-conditioned, the low-pressure refrigerant passage leading from the expansion valve 6 to the inlet of the rear side evaporator 7 is closed, and the rear side evaporator is closed. By closing the low-pressure refrigerant passage leading from the outlet of 7 to the expansion valve 6, the refrigerant is prevented from flowing into the rear evaporator 7 from the outlet of the front evaporator 5.

FIG. 2 is a side view showing the arrangement when the solenoid valve is attached to the rear evaporator together with the expansion valve. When connecting the solenoid valve 8 to the rear evaporator 7 together with the expansion valve 6, first, the joints of the corresponding refrigerant passages of the solenoid valve 8 and the expansion valve 6 are connected and integrated, and then the rear evaporation The refrigerant inlet pipe 71 and the refrigerant outlet pipe 72 protruding from the vessel 7 are connected to corresponding joints of the solenoid valve 8, and the high pressure refrigerant pipe and the low pressure refrigerant pipe (not shown) attached to the flange are connected to the expansion valve 6. Connect to the corresponding joint. Although not shown, a mounting plate 73 fixed across the refrigerant inlet pipe 71 and the refrigerant outlet pipe 72, a hole passing through the solenoid valve 8 and the expansion valve 6, a high-pressure refrigerant pipe and a low-pressure refrigerant pipe are fixed. A bolt is passed through the hole of the flange and the end is tightened with a nut, thereby completing the installation.

Next, the configuration of the solenoid valve 8 and the operation when power is not supplied will be described in detail. FIG. 3 is a side sectional view of the solenoid valve when power is not supplied. The solenoid valve 8 includes a low-pressure refrigerant passage hole 11 that sends out the low-pressure refrigerant adiabatically expanded by the expansion valve 6 to a refrigerant inlet pipe 71 of the rear evaporator 7, and a rear evaporator 7.
And a low-pressure refrigerant passage hole 12 through which the low-pressure refrigerant sent from the refrigerant outlet pipe 72 passes.

In the middle of the low-pressure refrigerant passage hole 11, a valve seat 14 having a reduced pipe diameter is formed, and a valve body 15 is disposed so as to be able to freely contact and separate from the valve seat 14 from the upstream side. Valve body 1
5 is a valve seat 14 provided by opening and closing a pilot hole 16 provided at the center thereof by an electromagnetic solenoid 20.
, And a state in which the low-pressure refrigerant passage hole 11 is opened by separating from the valve seat 14.

That is, when the electromagnetic coil 21 of the electromagnetic solenoid 20 is not energized, the pilot hole 16 is closed by a compression coil spring 24 inserted between the core 22 and the plunger 23 as shown in the figure. Have been.

As a result, the space between the valve element 15 and the plunger 23 has the same pressure as the upstream side through the leak hole 17 smaller than the pilot hole 16, whereby the valve element 15 is pressed against the valve seat 14. The low-pressure refrigerant passage hole 11 is closed. Therefore, a normally closed valve is arranged in the low-pressure refrigerant passage hole 11.

In the middle of the low-pressure refrigerant passage hole 12, there is provided a one-way valve 30 that allows only the refrigerant flow from the rear evaporator 7 to the expansion valve 6. That is, the valve seat 31 is formed in the low-pressure refrigerant passage hole 12, and the valve body 32 is arranged to be opposed to the valve seat 31 from the downstream side and urged in the closing direction by the compression coil spring 33.

The valve element 32 extends in the downstream direction.
For example, it has three legs, which are slidably inscribed on the inner wall of the low-pressure refrigerant passage hole 12 and guide the valve body 32 when the valve body 32 moves toward and away from the valve seat 31. It has become.

Therefore, as shown in the figure, when the solenoid valve is closed by de-energization and there is no refrigerant flow in the low-pressure refrigerant passage hole 12, the valve body 32 is actuated by the urging force of the compression coil spring 33. The low-pressure refrigerant passage hole 12 is always pressed against the valve seat 31 and is closed.

The above is the operation of the solenoid valve 8 when the vehicle air conditioner is stopped or when air conditioning is performed only on the front side and air conditioning on the rear side is stopped.
The operation of the solenoid valve 8 when the rear side air conditioning is also performed will be described.

FIG. 4 is a side sectional view of the solenoid valve during the energizing operation. When performing air conditioning on the rear side, the electromagnetic coil 21 of the electromagnetic solenoid 20 is energized. Thereby, the plunger 23 is sucked by the core 22 and separated from the pilot hole 16 of the valve body 15.

Here, when the high-pressure refrigerant supplied from the liquid receiver 3 is adiabatically expanded by the expansion valve 6 and enters the low-pressure refrigerant passage hole 11 of the solenoid valve 8, the supply pressure causes the valve body 15 to move through the valve body 15. Pushed in the direction away from the seat 14, the low-pressure refrigerant passage hole 11 is fully opened. Thereafter, the refrigerant that has passed through the electromagnetic valve 8 is supplied to the rear-side evaporator 7 through the refrigerant inlet pipe 71, where heat exchange with indoor air is performed and the refrigerant is evaporated.

The refrigerant evaporated by the rear evaporator 7 is sent out from the refrigerant outlet pipe 72 and enters the low-pressure refrigerant passage hole 12 of the solenoid valve 8. The supply pressure of the refrigerant that has entered the low-pressure refrigerant passage hole 12 pushes the valve body 32 of the one-way valve 30 to the downstream side, and the low-pressure refrigerant passage hole 12 is fully opened.

The refrigerant having passed through the one-way valve 30 flows through the expansion valve 6 and joins the outlet side of the front-side evaporator 5. When the refrigerant passes through the expansion valve 6, the expansion valve 6 senses the temperature and pressure of the refrigerant, the valve opening is controlled in accordance with the temperature and pressure of the refrigerant, and the refrigerant sent to the rear-side evaporator 7 Is adjusted.

In this way, switching between closing and opening the low-pressure refrigerant passage hole 11 on the inlet side of the rear evaporator 7 can be performed depending on whether or not the electromagnetic solenoid 20 is energized. The valve 30 can also automatically switch between closing and opening the low-pressure refrigerant passage hole 12 on the outlet side of the rear-side evaporator 7. Therefore, when the entrance of the rear side evaporator 7 is closed, the refrigerant flowing through the front side evaporator 5 does not enter the rear side evaporator 7, so that the refrigerant enters the rear side evaporator 7. This prevents the refrigerant from entering and accumulating in the refrigeration cycle, thereby reducing the amount of circulating refrigerant in the refrigeration cycle on the front side and causing the front side to run out of cooling power.

In the above embodiment, the one-way valve 30 is used in order to prevent the refrigerant from flowing back to the rear evaporator 7 when the air conditioning on the rear side is not performed. Instead of the directional valve 30, a constant differential pressure valve that causes a predetermined pressure loss (for example, 0.03 MPa) in the refrigerant flowing in the forward direction can be used.

By using this constant differential pressure valve, when air conditioning on the rear side is performed, the evaporation temperature of the rear evaporator 7 is higher than the evaporation temperature of the front evaporator 5 (for example, 3
° C), and the refrigerant flow does not compete between the rear side and the front side. This eliminates the need for a conventional anti-competition measure, that is, setting the superheat on the rear side larger than the superheat setting on the front side. The same can be used.

[0031]

As described above, in the present invention, a one-way valve is provided in the refrigerant flow path connected to the outlet side of the evaporator. As a result, when air conditioning is performed only on the front side, the refrigerant flowing through the refrigeration cycle is blocked by the solenoid valve at the inlet of the evaporator and the one-way valve at the outlet, so that the refrigerant may enter and accumulate in the evaporator. Disappears.

Also, by using a constant differential pressure valve as the one-way valve, the rear side evaporating temperature can be higher than the front side evaporating temperature during the rear side air conditioning.
Competition of refrigerant flow rates can be avoided.

Further, since the one-way valve is provided in the connection adapter provided with the solenoid valve, the connection with the evaporator and its piping can be performed by the same operation as the conventional expansion valve with the solenoid valve. it can.

[Brief description of the drawings]

FIG. 1 is a system diagram of a vehicle air conditioner showing a refrigeration cycle to which an electromagnetic valve according to the present invention is applied.

FIG. 2 is a side view showing an arrangement when an electromagnetic valve is attached to a rear evaporator together with an expansion valve.

FIG. 3 is a side sectional view of the solenoid valve when power is not supplied.

FIG. 4 is a side sectional view of the solenoid valve during an energizing operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 3 Liquid receiver 4 Expansion valve 5 Front-side evaporator 6 Expansion valve 7 Rear-side evaporator 8 Solenoid valve 11, 12 Low-pressure refrigerant passage hole 13 Body 14 Valve seat 15 Valve body 16 Pilot hole 17 Leak hole Reference Signs List 20 electromagnetic solenoid 21 electromagnetic coil 22 core 23 plunger 24 compression coil spring 30 one-way valve 31 valve seat 32 valve body 33 compression coil spring 71 refrigerant inlet pipe 72 refrigerant outlet pipe 73 mounting plate

Claims (2)

[Claims] 1. A valve element disposed in a first refrigerant flow path interposed between an expansion valve and an evaporator, for supplying refrigerant from the expansion valve to a refrigerant inlet pipe of the evaporator. The solenoid valve is configured to be closed / opened by a solenoid operation. The solenoid valve is provided in a second refrigerant flow path that guides the refrigerant delivered from the refrigerant outlet pipe of the evaporator to the expansion valve, and the evaporator controls the expansion valve from the evaporator. An electromagnetic valve comprising a one-way valve that allows a refrigerant flow only in a direction. 2. The solenoid valve according to claim 1, wherein the one-way valve is a constant differential pressure valve that causes a predetermined pressure loss in a forward-flowing refrigerant.