Patent Application
20120091375
1. Field of the Invention
The present invention relates to an electrically operated valve which is used in an air conditioning system such as a car air conditioner or the like.
2. Description of the Conventional Art
Conventionally, in the case of an outdoor parking space or the like, in a vehicle which is parked under a burning scorching, a sun beam streams in a vehicle inside, and an in-vehicle temperature becomes considerably high. In the vehicle put under such a special environment, even if an engine of the vehicle is started and an air conditioner is operated, there is seen such a phenomenon that a high-temperature air is spouted at the beginning from an air outlet of the air conditioner, and even if the air conditioner comes to a normal operation state and a cold air is blown, a considerable time is demanded until the in-vehicle temperature is lowered to a comfortable temperature.
A flow rate control valve is provided for controlling a flow rate of a cooling medium circulating the air conditioner and there can be considered to control the flow rate control valve in such a manner that a high flow rate flows at a time of starting the engine, while taking the condition mentioned above into consideration.
The assignee of the present invention has proposed an electrically operated valve for stably operating in Japanese Patent No. 4224187 in which the electrically operated valve is downsized by shortening a whole length, a rotation of a rotor opening and closing a valve port is stabilized, and the rotor is less inclined even at a time when the rotor is regulated by a stopper.
The electrically operated valve described in Japanese Patent No. 4224187 is provided with a valve main body which regulates a passing flow rate by a valve body coming close to and away from a valve seat within a valve chamber by a valve shaft, a can which has a rotor firmly attached to the valve main body and moving the valve body close to and away from the valve seat built-in, and a stator which is outward fitted to the can and rotationally drive the rotor, a drive mechanism moving the valve body close to and away from the valve seat is a screw feeding mechanism constructed by a guide bush which extends out of the valve main body in a rotor direction so as to be fixed and in which a fixed thread portion is formed, and a valve shaft holder which supports the rotor and has a moving thread portion screwing together with the fixed thread portion of the guide bush, the valve shaft holder and an upper end portion of the rotor is fixed by swaging via a support ring, and the support ring has a groove portion in an outer periphery of a swaging fixed portion. Since the screw feeding mechanism is arranged within the rotor, a whole length of the can and an outer diameter of the valve main body become smaller so as to achieve a downsizing of the electrically operated valve. Further if the rotor is rotated by exciting and magnetizing the stator, a rotation of the rotor becomes stabilized and a swing of the rotor with respect to a rotating shaft is reduced since the screw feeding mechanism supporting and driving the rotor is arranged within the rotor.
In the electrically operated valve mentioned above, a rotation control of the rotor is initiated by setting a valve closed state to a reference position. Further, since the rotation of the motor is converted into an elevating motion of a needle on the basis of a screw action, a flow rate flowing through the valve does not come to a maximum flow rate until the needle valve rises and a leading end of the needle comes to a state of completely coming off from the valve seat. Since a long time is demanded until the needle valve completely comes off from the valve seat, a prompt behavior in response to a condition can not be achieved by the electrically operated valve mentioned above.
In an electrically operated valve, it is preferable that a high flow rate can be secured immediately at the same time of turning on a power supply. An object of the present invention is to provide an electrically operated valve starting a control from a valve closed state, in which the electrically operated valve can enlarge a flow rate in a moment of time after driving such as turning on a power supply, whereby it is possible to early lower an in-vehicle temperature, for example, by spouting a cold air from an air conditioner in a moment of time after starting an engine.
In order to achieve the object mentioned above, an electrically operated valve according to the present invention is provided,
In accordance with the present electrically operated valve, the first valve body comes into contact with the first valve seat so as to press the second valve body, and the second valve body comes into contact with the second valve seat, whereby the first valve body and the second valve body respectively come to seated states on the first valve seat and the second valve seat. Next, if the first valve body moves up together with the second valve body in a state of coming into contact with the first valve seat, and the second valve body comes away from the second valve seat, the fluid flows through an opening (a gap) produced between the second valve body and the second valve seat (or the third valve seat). If the second valve body further moves up in a state in which the first valve body comes into contact with the first valve seat, the second valve body come to a seated state on the third valve seat. If the first valve body further moves up from this state, the first valve body moves away from the first valve seat while maintaining the second valve body coming into contact with the third vale seat, and the fluid flows through an opening (a gap).
Since the electrically operated valve according to the present invention is structured as mentioned above, the second valve body seats on the second valve seat or the third valve seat in a state in which the first valve body seats on the first valve seat, whereby the electrically operated valve comes to a so-called closed state (including a case of allowing a very small flow rate flowing in the case that a means for circulating the very small flow rate is provided). Further, it is possible to make a flow rate flowing through the electrically operated valve in this state large, by widening the opening (the gap) produced between the second valve body and the second valve seat by the second valve body coming away from the second valve seat. Further, the large flow rate of flow is blocked in the state in which the second valve body seats on the third valve seat, and it is possible to make the flow rate flowing through the electrically operated valve in this state small, by thereafter narrowing the opening (the gap) produced between the first valve body and the first valve seat at a time when the first valve body moves away from the first valve seat.
As a result, if the state in which the first valve body seats on the first valve seat and the second valve body seats in the second valve seat is set to the valve closed state for starting the control, it is possible to immediately achieve a high flow rate at a time when the second valve body moves away from the second valve seat from the closed valve state.
Further, in the case that the present electrically operated valve is applied to the air conditioner for the vehicle, the second valve body comes away from the second valve seat by turning on the power supply to the electrically operated valve, thereby achieving a state in which a large flow rate of cooling medium can be circulated for a short time, and the air conditioner can early spout a large amount of cooling air.
An embodiment of an electrically operated valve according to the present invention will be described on the basis of the accompanying drawings.
Further, the valve body 23 is a generic name of a first valve body 51 and a second valve body 52 which are described in detail with regard to
The can 40 is formed as a closed-end cylindrical shape which is formed by a nonmagnetic metal such as a stainless steel or the like, is firmly attached to a collar plate 41 made of a stainless steel by the welding or the like, which is firmly attached to an upper portion of the valve main body 20, and is kept in an airtight state in its inner portion. In the valve main body 20, a fluid inflow pipe 20a in a vertical direction and a fluid outflow pipe 20b in a horizontal direction are extended out. In this case, the fluid flow direction may be inverted (the pipe 20a is used as the fluid outflow pipe, and the pipe 20b is used as the fluid inflow pipe).
The first valve body 51 of the valve body 23 constructed by a needle valve is formed in a lower end of a valve shaft 24 made of a brass. A drive mechanism moving the valve body 23 close to and away from the valve seat 22 is a screw feeding mechanism constructed by a tubular guide bush 26 which extends out in a direction of the rotor 30 from the valve main body 20 so as to be fixed and in which a fixed thread portion (a male thread portion) 25 is formed, and a valve shaft holder 32 which has a moving thread portion (a female thread portion) 31 engaging with the fixed thread portion 25 of the guide bush 26, and the thread feeding mechanism is arranged approximately in a center portion of a whole length in an axial direction within the rotor 30.
In the electrically operated valve shown in the present embodiment, a length in the axial direction and an outer diameter of the valve main body are widely reduced in comparison with the structure in which the screw feeding mechanism is positioned below the rotor such as the conventional electrically operated valve, whereby it is possible to achieve a downsizing of the electrically operated valve. The fixed thread portion 25 is constructed by a male thread in an outer periphery of the guide bush 26, and the moving thread portion 31 is constructed by a female thread in an inner periphery of the valve shaft holder 32. In this case, the guide bush 26 and the valve shaft holder 32 are both formed by a cylindrical member made of a brass.
The valve shaft holder 32 is formed as a below opened cylindrical shape which is positioned in an outer side of the guide bush 26, and is structured such that the moving thread portion 31 is formed in an inner surface thereof as mentioned above, and an upper contracted portion of the valve shaft 24 is fitted to a center of the valve shaft holder 32 so as to be connected by a push nut 33. The valve shaft 24 forming the valve body 23 in a lower end thereof is constructed by a brass, is fitted and inserted to the center of the valve shaft holder 32 so as to be movable up and down, and is energized normally downward by a compression coil spring 34 which is provided in a compressing manner within the valve shaft holder 32. A pressure equalizing hole 32a achieving a pressure equalization within the valve chamber 21 and the can 40 is formed in a side surface of the guide bush 26.
A restoring spring 35 constructed by a cylindrical compression coil spring is attached to an outer periphery of the bush nut 33 which is pressed into and fixed to an upper end of the valve shaft 24, and when a screw engagement between the fixed thread portion 25 of the guide bush 26 and the moving thread portion 31 of the valve shaft holder 32 comes off, the restoring spring 35 comes into contact with an inner surface of a top portion of the can 40 so as to energize in such a manner as to restore the screw engagement between the fixed thread portion 25 and the moving thread portion 31. The restoring spring 35 may be attached in a state of being loosely fitted to an outer periphery of the push nut 33 so as to be mounted, or may be attached in such a manner as to come into elastic contact with the outer periphery of the push nut 33.
The valve main body 20 is constructed by a metal such as a brass or the like, and a joint with the can 40 is carried out by butt welding of the can end portion to a step portion of the collar plate 41 which is firmly attached to the valve main body 20 by welding or the like. In this case, not being limited to the but welding, the end portion of the can 40 may be folded flat in an outer periphery so as to be formed as a collar portion, and the collar portion and the collar plate 41 may be fixed by a so-called put-together hands welding.
The valve shaft holder 32 and the rotor 30 are connected via a support ring 36, and the support ring 36 is constructed by a metal ring made of a brass in the present embodiment which is inserted at a time of forming the rotor 30. An upper protruding portion of the valve shaft holder 32 is fitted to an inner peripheral hole portion of the support ring 36, and the rotor 30, the support ring 36 and the valve shaft holder 32 are connected by caulking an outer periphery of the protruding portion. The valve main body 20, the valve shaft 24, the guide bush 26, the valve shaft holder 32 and the support ring 36 are all made of the brass as mentioned above by taking a recycle into consideration. Further, since each of the parts is connected by pressure insertion and caulking, it is possible to reuse for example the rotor 30 by removing the caulking between the valve shaft holder 32 and the support ring 36. In this case, it goes without saying that the other metals than the brass, for example, a stainless steel can be used. Further, it goes without saying that the other metals than the brass, for example, a stainless steel can be used only in the valve shaft 24.
A lower stopper body (a fixed stopper) 27 constructing one side of a stopper mechanism is firmly attached to the guide bush 26, and the lower stopper body 27 is constructed by a ring-like plastic, and is provided in a protruding manner in an upper portion with a plate-like lower stopper piece 27a. Further, an upper stopper body (a moving stopper) 37 constructing the other side of the stopper mechanism is firmly attached to the valve shaft holder 32, and the upper stopper body 37 is also constructed by a ring-like plastic, and is provided in a protruding manner with a plate-like upper stopper 37a toward a lower side so as to be capable of engaging with the lower stopper piece 27a mentioned above.
The lower stopper body 27 is firmly attached to a spiral groove portion 26a formed in an outer periphery of the guide bush 26 by an injection molding, and the upper stopper body 37 is firmly attached to a spiral groove portion 32b formed in an outer periphery of the valve shaft holder 32 by an injection molding. In this case, it goes without saying that the lower stopper body 27 and the upper stopper body 37 may be firmly attached by an adhesion, a pressure insertion or the like without being limited to the injection molding.
A description will be given of a motion of the electrically operated valve 10 structured as mentioned above. If the coil of the stator is excited by applying an electricity, the rotor 30 and the valve shaft holder 32 are rotated with respect to the guide bush 26 which is firmly attached to the valve main body 20, and the valve shaft holder 32 moves up and down in an axial direction thereof by the screw feeding mechanism of the fixed thread portion 25 of the guide bush 26 and the moving thread portion 31 of the valve shaft holder 32. In correspondence to an exciting direction, the valve shaft holder 32 moves, for example, downward, and the valve body 23 seats on the valve seat 22 or comes away from the valve seat 22.
At a time point when the valve body seats (at a time point when the first valve body 51 presses the second valve body 52 and the second valve body 52 seats on the second valve seat 54), the upper stopper body 37 does not come into contact with the lower stopper body 27, and the rotor 30 and the valve shaft holder 32 further rotate and move downward while the valve body 23 keeps seating. At this time, a relative downward displacement of the valve shaft holder 32 with respect to the valve shaft 24 is absorbed by that the compression coil spring 34 being compressed. Thereafter, the rotor 30 further rotates, the valve shaft holder 32 moves downward and the stopper piece 37a of the upper stopper body 37 comes into contact with the stopper piece 27a of the lower stopper body 27. The downward movement of the valve shaft holder 32 is forcibly stopped by the contact between the stopper pieces 27a and 37a, even if the current application to the stator is carried over.
Since the stopper mechanism constructed by the upper stopper body 37 and the lower stopper body 27 is arranged within a total length in the axial direction of the rotor 30, the rotor 30 and the valve shaft holder 32 is hardly ever inclined largely even in the case that the stopper mechanism functions, an actuation thereof is stabilized, and it is possible to smoothly carry out an actuation even in the case that the rotor 30 is next rotated inverse.
If the current application to the stator is carried out in an inverse direction, the rotor 30 and the valve shaft holder 32 are rotated in the inverse direction to the above with respect to the guide bush 26, the valve shaft holder 32 moves upward and the valve body 23 in the lower end of the valve shaft 24 comes away from the valve seat 22 by the screw feeding mechanism mentioned above, and the cooling medium can pass. A passing amount of the cooling medium can be regulated by changing a valve opening degree according to an amount of rotation of the rotor 30. Since the amount of rotation of the rotor 30 is regulated by an input pulse number to a pulse motor, it is possible to accurately regulate the passing amount of the cooling medium.
As mentioned above, the rotation of the rotor 30 is converted into an axial movement of the rotor 30, the valve shaft holder 32 and the valve shaft 24 by the screw feeding mechanism constructed by the fixed thread portion 25 of the guide bush 26 and the moving thread portion 31 of the valve shaft holder 32. Since the screw feeding mechanism is positioned particularly in the center portion within the rotor 30 and the support and the drive of the rotor 30 are carried within a total length of the rotor 30, the rotor 30 is hardly oscillated at a time of rotating, and it is possible to stably rotate.
A substantial part of the present embodiment of the electrically operated valve is shown as an enlarged cross sectional view in
The valve chamber 21 formed in the valve main body 20 is provided with the second valve seat 54 and the third valve seat 56 which are formed larger in diameter than the first valve seat 53. An annular corner portion 21a of the step portion of the valve chamber 21 comes to the second valve seat 54, and an outer periphery lower edge portion 52a can seat on the second valve seat 54 at a time when the ring-like second valve body 52 moves down. A ring-like valve seat body 55 is fixed to the valve chamber 21 at an above position of the second valve body 52 by a means such as a pressure insertion or the like. A center portion of the valve seat body 55 comes to a through hole 55a for constructing the ring, and the valve shaft 24 and the needle valve can be inserted via a gap with respect to the through hole 55a. An inner peripheral lower edge portion 55b of the valve seat body 55 comes to the third valve seat 56, and when the second valve body 52 moves up, an outer peripheral upper edge portion 52b thereof can seat on the inner peripheral lower edge portion 55b of the valve seat body 55.
An orifice 16 which is open to a bottom surface of the valve main body 20 is formed in the bottom portion 15 of the valve chamber 21, and a coil spring 57 is arranged in a compressed state between the bottom portion 15 and the second valve body 52, in such a manner as to prevent an interference with the orifice 16. The first valve body 51 comes into contact with (seats on) the first valve seat 53 on the second valve body 52 by pressing the second valve body 52 at a time when the first valve body 51 moves downward. In this state, the second valve body 52 moves down or up in correspondence to the upward movement or the downward movement of the first valve body 51, whereby the second valve body 52 moves close to and away from the second valve seat 54 or the third valve seat 56, and a fluid flow rate control is carried out between the first valve body 51 and the second valve body 52 (in other words, the outer peripheral portion of the closed second valve body 52) and between the second valve seat 54 and the third valve seat 56.
Further, if the first valve body 51 is pulled up from the state in which the first valve body 51 and the second valve body 52 come into contact, the second valve body 52 moves up on the basis of a snapping force of the coil spring 57, the second valve body 52 comes into contact with the third valve seat 56, and only the first valve body 51 can move up thereafter, whereby a flow rate control is carried out between the first valve body 51 and the first valve seat 53.
In this case, the through hole 52d coming to an orifice portion of the second valve body 52 is formed smaller in diameter than the second valve seat 54 and the third valve seat 56. Further, in this embodiment, the first valve seat 53 is approximately the same diameter as the orifice 16.
It is preferable that the electrically operated valve 10 stops the rotation of the stepping motor at a time of the control starting valve closed state, that is, at a time when the first valve body 51 comes into contact with and press the second valve body 52 and the second valve body 52 seats on the second valve seat 54. However, since the parts and the assembled products have dispersion, the compression coil spring 34 is put for absorbing such the dispersion, The electrically operated valve 10 is stopped after the valve closed state by ensuring that the valve closed state mentioned above is achieved before both the stoppers 27 and 37 come into contact, and thereafter continuously moving the rotor while compressing the compression coil spring 34 until both the stoppers 27 and 37 come into contact. Further, as a result of this, at a time of inversely rotating the stepping motor so as to change from the control starting valve closed state to the valve open state, both the stoppers 27 and 37 break away from the contact state with each other at first several pulses after the power supply is turned on, however, the valve closed state is maintained.
Since the first valve seat 53 is small in its valve seat aperture as is different form the second valve seat 54 and the third valve seat 56, and the needle portion is accessorily provided in the first valve body 51 at its leading end, it is possible to make a change of the opening area per unit pulse (one pulse for the stepping motor driving pulse) minute in the case that only the first valve body 51 moves up from the first valve seat 53. The fine flow rate control carried out by the conventional electrically operated valve such as the Japanese Patent No. 4224187 is carried out by the first valve body 51 in the present state.
In the electrically operated valve 10, the pulse position until reaching the maximum flow rate varies in accordance with a precision per product (or a used part). Accordingly, it is preferable to reduce a dispersion of the maximum flow rate by setting a range of the valve opening degree at which the maximum flow rate becomes flat even if the valve opening degree deviates in some degree. In other words, if the maximum flow rate characteristic indicates a steep triangular mountain characteristic without becoming flat, it is not secured that the flow rate at a time when the elevating motion of the valve stops is the maximum flow rate. It is possible to carry out the valve opening degree control aiming at the maximum flow rate by being provided with the characteristic at which the maximum flow rate becomes flat.
Long and short of it is that it is possible to absolutely secure the maximum flow rate in the region (B) even if a somewhat difference is generated between the valve opening degree assumed by the pulse number input to the stepping motor and the actual valve opening degree, by being provided with the flat maximum flow rate portion (B′) mentioned above.
In the state (C) shown in
In the embodiment mentioned above, the description is given of the embodiment in which the coil spring 57 is provided, however, in the case that the fluid flows into from the second valve seat 54 side (the fluid inflow pipe 20a side), the second valve body 52 is pressed to the third valve seat 56 side on the basis of the fluid pressure. Accordingly, in the case that the electrically operated valve 10 is used as mentioned above, the coil spring 57 can be omitted.
Further, it goes without saying that it is possible to appropriately set the bore diameters of the first valve seat 53, the second valve seat 54, the third valve seat 56 and the orifice 16 on the basis of the specification required in the electrically operated valve.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-233536 | Oct 2010 | JP | national |
