JPH0621679B2 - 4-way switching valve - Google Patents

Description

The present invention relates to a four-way switching valve, and more particularly to a four-way switching valve for reversing the flow direction of a refrigerant used in a heat pump type cooling and heating device.

2. Description of the Related Art When an air conditioner is constructed using a heat pump type refrigeration cycle, cooling / heating is switched by changing the flow direction of the refrigerant. A four-way switching valve has been conventionally used to change the flow direction of the fluid, but it is preferable to use an electromagnetic four-way valve because it is easy to control and the structure is simple. However, since the electromagnetic four-way valve has a small moving distance of the valve body and an operating force is not so strong, it is suitable for switching a small flow rate of fluid, but is not necessarily suitable for a large flow rate. Therefore, the electromagnetic four-way valve is only used as a pilot valve for controlling a fluid pressure operated four-way valve suitable for switching a large flow rate of fluid.

However, such an electromagnetic pilot type fluid pressure operated valve has a drawback that it cannot operate unless there is a differential pressure in the supplied fluid, and the structure is complicated so that it cannot be instantaneously switched.
Therefore, various electric four-way switching valves have been proposed which are fast in operation and can directly switch a large flow rate regardless of the fluid pressure.

As such an electric four-way switching valve, as shown in FIG. 7, a drive motor 21 is connected to a slide valve body 23 via a reduction gear 22. This valve has a rotary shaft 25 so that the valve body 23 slides in contact with the valve seat 24.
Is provided, and a bearing seal 28 is provided at a portion where the drive shaft 26 coupled to the gear 22 and the valve body 23 penetrates the wall surface of the valve body 27. However, the four-way switching valve having such a structure needs to be manufactured particularly precisely because the seal 28 does not leak and the valve seat 24 does not leak and the valve can operate smoothly. However, it has a drawback that not only is it expensive, but the life of the seal portion is short.

Further, by replacing the electromagnetic actuator in the conventional electromagnetic four-way valve with a motor, the moving distance of the valve element is increased to directly switch the large flow rate, which is disclosed, for example, in JP-A-58-21069. There is a motorized four-way valve (Fig. 8). In this valve, a rotor 31 having a female thread in the center is screwed and coupled with a valve body drive shaft 32 having a thread on its periphery, and a fixed coil 33 provided outside the valve body is energized. By this, the rotation of the rotor 31 is converted into a linear movement of the valve body drive shaft 32 in the length direction, whereby the cap-shaped valve body 35 is slid in a state of being in contact with the valve seat 34 and The fluid port is configured to be switched. However, in this four-way valve, the bearing portion 36 of the rotor 31 becomes large and high precision is required, as well as the screw connection portion with the valve body drive shaft 32 needs high precision, which inevitably results in high price. There wasn't.

Problems to be Solved The conventional electric four-way switching valve has an advantage that it can quickly switch a large flow passage even if the fluid pressure is low. In order to reduce the leakage of fluid in the valve, it is necessary to manufacture the entire valve body drive mechanism with high accuracy, and it is also necessary to incorporate a large-sized actuator with high accuracy. There was a problem that it was not expensive.

Therefore, the present invention is capable of reversing the fluid flow direction by rapidly switching the flow path of a large flow rate irrespective of the pressure of the fluid despite its small size, and there is a fear of leakage between the valve seat and the valve body. The purpose is to economically provide a high-reliability four-way switching valve that does not have any.

[Structure of the Invention] Means for Solving the Problems A four-way switching valve for reversing the fluid flow direction capable of achieving the above object is a low-pressure fluid outflow port formed on the inner surface of a valve chamber to which high-pressure fluid is supplied. And a valve seat having two fluid inlet / outlet ports opened, a through hole formed in the valve body wall facing the outlet port, and one end exposed to the outside of the valve body so as to be immovable in the axial direction. A rotary drive shaft penetratingly provided in the through hole, a seal mechanism provided in the through hole surrounding the drive shaft, and a spring biased toward the valve seat so that an edge portion contacts the valve seat. And a bowl-shaped valve body that is slidable and selectively communicates between the outflow port and one of the inflow and outflow ports, and a valve body that is coupled to the drive shaft and holds the valve body so as to be slightly movable. It is characterized by comprising a support.

Operation In the four-way switching valve of the present invention, the bowl-shaped valve element is held by the valve element support body so as to be slightly movable so that the central portion of the back surface is pushed vertically toward the valve seat, so that it is stable. It can be positioned on the valve seat in a posture, and the drive shaft connected to the valve body support is pierced in the through hole so that it cannot move in the axial direction. It doesn't take. That is, since the contact between the valve body and the valve seat and the seal between the drive shaft and the valve body wall do not interfere with each other, it is not possible for the drive shaft seal mechanism when the drive shaft rotates. It can rotate smoothly without applying force, and even if the posture of the valve body support changes slightly, the fluid pressure in the valve chamber ensures that the valve body self-adheres to the valve seat. Does not happen,
Therefore, fluid leakage is unlikely to occur.

Embodiment 1 An example of the four-way switching valve of the present invention is shown in FIGS. Reference numeral 1 is a valve body, and 2 is a valve seat. Valve body 1 and valve seat 2
A valve chamber 3 is formed surrounded by and. In the valve seat 2, for example, a high pressure fluid inflow port D communicating with the compressor discharge side, fluid inflow / outflow ports A and B respectively communicating with the two heat exchangers, and a low pressure fluid outflow port C communicating with the compressor suction side. Is provided.

Reference numeral 4 denotes a long bowl-shaped valve element that can slide on the surface of the valve seat 2 in the valve chamber 3. The valve body 4 can be positioned so as to simultaneously cover either one of the inlet / outlet port A or B and the outlet port C, and a recess having a size large enough to serve as a flow path for a fluid flowing between these ports. Is formed. Reference numeral 5 is a support body, and 6 is a drive shaft connected to the valve body support 5. The valve body support 5 has side wall portions 5a, 5a on both sides and also has a claw portion 5b between which the valve body 4 is held so as to be slightly movable. Further, the central portion of the back surface of the valve body 4 is lightly pressed vertically toward the valve seat by the restraining spring 5c provided on the valve body support body 5 so that the valve body 4 does not separate from the valve seat 2. is there.

The drive shaft 6 is connected to the valve body support 5 and is provided so as to be perpendicular to the valve seat 2 in a through hole 1 a provided in the wall of the valve body 1 so as to face the outflow port C. ing.
A seal mechanism 7 including an inner sleeve 7a with a collar, an outer sleeve 7b with a collar, and a packing 7c is provided in the through hole 1a.
Is provided to hermetically seal between the inner surface of the through hole 1a and the outer surface of the drive shaft 6, and the drive shaft 6 cannot move in the axial direction but does not hinder its rotation. A drive lever 8 is attached to the outer end of the drive shaft 6.

The drive lever 8 may be driven by a suitable actuator, for example, a fluid pressure actuator equipped with a diaphragm, a bellows, a piston, or the like, or may be manually operated. When the drive shaft 6 is rotated in this way, the valve body support 5 only exerts a force on the valve body 4 parallel to the surface of the valve seat 2, and
The valve body 4 can smoothly slide on the surface of the valve seat 2, and is crimped to the valve seat 2 due to the pressure difference between the high pressure fluid in the valve chamber 3 and the low pressure fluid on the port C side at a predetermined switching position. Then, the flow path switching is completed.

Further, the port arrangement of the valve of this example is not necessarily as shown in FIG. 3, but may be as shown in FIG. 4, for example. In this example, the high pressure fluid inflow port opens directly to the wall surface of the valve chamber 3, and the valve seat 2'is provided with only the inflow / outflow ports A'and B'and the outflow port C ', but the valve body 4 The structure and function of the valve body support 5 are exactly the same.

FIG. 5 is an example of a valve drive system when the four-way switching valve of this example is used in a vehicle air conditioner. Reference numeral 9 is a diaphragm type actuator that operates by negative pressure in the intake line of the engine, and is controlled by a two-way solenoid valve 10. 9
a is a diaphragm, 9b is an equalizer hole, 9c is an air inlet / outlet, and its output is transmitted to the drive lever 8 by the arm 9d.

Embodiment 2 Another embodiment of the four-way switching valve of the present invention is shown in FIG. In this example, the valve body 11, the valve seat 12, the valve body 14, the valve body support 15, the drive shaft 16 and the seal mechanism 17 are exactly the same as those in the first embodiment, but a plurality of sets are provided on the back side of the valve body 11. A gear mechanism 18 composed of a reduction gear and an electric motor 19 for driving the gear mechanism 18 are attached, and a fan gear 8a provided at the end of the gear mechanism 18 transmits torque to the drive shaft 16.

The function of the four-way switching valve of this example is exactly the same as that of the valve of the first embodiment.

〔The invention's effect〕

In the four-way switching valve of the present invention, the valve element is held by the valve element support so as to be slightly movable, and the central portion of the back surface is vertically pushed by the spring toward the valve seat. Therefore, when the valve body support body rotates due to the rotation of the drive shaft, the valve body can smoothly slide on the valve seat, and the fluid pressure causes the valve body to adhere to the valve seat without difficulty, so that no leakage occurs. In addition, since the face of the valve seat and the face of the valve body and the face of the seal part where the drive shaft is in contact do not apply unreasonable force, they are less susceptible to wear and damage and may leak over a long period of time. It does not occur, and it is highly reliable because it can quickly reverse the flow direction of a large amount of fluid despite its small size. Further, it has an advantage that it has a simple structure, is easy to manufacture, and can be manufactured economically.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view showing a structure of an embodiment of a four-way switching valve of the present invention, FIG. 2 is a perspective view showing a combined state of a valve body and a valve body support body in the above example, and FIG. Is an explanatory view showing the relationship between the valve seat and the valve body in the above example, FIG. 4 is an explanatory view showing the relationship between the valve seat and the valve body in another mode, and FIG. 5 is the four way switching valve of the above example. FIG. 6 is an explanatory view of an example of a drive mode when the vehicle is used for a vehicle air conditioner, FIG. 6 is a partially cutaway sectional view showing the structure of another embodiment of the four-way switching valve of the present invention, FIG. 7 and FIG. Each of the drawings is a sectional view showing the structure of a conventional four-way switching valve. 1,11 ... Valve body, 2,12 ... Valve seat, 3,13
... Valve chamber, 4,14 ... Valve element, 5,15 ... Valve element support, 6,16 ... Drive shaft, 7,17 ... Seal mechanism, 8
...... Drive lever, 8a ...... fan gear, 9 ...... diaphragm type actuator, 10 ...... 2-way solenoid valve, 18 ...... gear mechanism, 19 ...... electric motor, A, B ...... in / out port,
C ... Outflow port, D ... High pressure fluid port, 21 ... Motor, 22 ... Reduction gear, 23 ... Valve body, 24 ... Valve seat, 25 ... Rotating shaft, 26 ... Drive shaft, 27 ... ... Valve body, 28 ... Bearing seal, 31 ... Rotor, 32 ... Valve drive shaft, 33 ... Fixed coil, 34 ... Valve seat, 3
5 ... Valve element, 36 ... Bearing section.

Claims (1)

[Claims] 1. A valve seat, which is formed on the inner surface of a valve chamber to which high-pressure fluid is supplied and has an outlet port for low-pressure fluid and two inlet and outlet ports for fluid, and a valve body wall facing the outlet port. A through hole is provided, a rotary drive shaft having one end exposed to the outside of the valve body so as to be immovable in the axial direction, and a rotary drive shaft provided inside the through hole so as to surround the drive shaft. And a bowl-shaped valve that is spring-biased toward the valve seat and has an edge contacting and sliding with the valve seat, and selectively communicating between the outflow port and the inflow / outflow port. A four-way switching valve for reversing a fluid flow direction, comprising a body and a valve body support body which is connected to the drive shaft and holds the valve body so as to be slightly movable.