JP2006233807A - Ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ejector capable of adjusting passage area of a nozzle throat part by a needle and reducing coaxiality of the needle and the nozzle throat part easily. <P>SOLUTION: The management items for reducing coaxiality of the needle and the throat part by pressing a guide 4 holding the needle 3 slidably into a nozzle 2 are following three items: (1) coaxiality of a hole 20 in which the guide 4 is pressed and the throat part 23 in the nozzle 2, (2) coaxiality of a large diameter circular cylindrical part 40 pressed into the nozzle 2 and a guide hole 43 for guiding the needle 3 in the guide 4, and (3) assembly coaxiality when pressing the guide 4 into the nozzle 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ejector that sucks suction fluid by an energy exchange action when jetting drive fluid from a nozzle, and more particularly to an ejector that adjusts a passage area of a nozzle throat by a needle.

Conventionally, an ejector used in a refrigeration cycle moves a needle in an axial direction using a stepping motor, thereby changing a passage area of a nozzle throat. Moreover, the guide and nozzle which hold | maintain a needle | hook slidably are fixed to the body (for example, refer patent document 1).
JP 2004-270460 A

  However, in the conventional ejector, when the axes of the needle and the nozzle throat are shifted, wear due to sliding between the nozzle and the needle occurs. If this wear becomes significant, for example, if you want to increase the high pressure by tightening the throttle (reducing the passage area of the nozzle throat), the throttle will be insufficient, and the refrigeration cycle cannot be operated with an appropriate balance. , System performance is greatly reduced.

  For these problems, measures are taken to reduce the coaxiality (axial misalignment) between the needle and the nozzle throat while improving the wear resistance by the material. Further, in order to achieve a high degree of coaxiality, a connection structure between the cylindrical portions, particularly preferably a press-fitting structure is employed for the connection between the parts. Note that high accuracy of the coaxiality means that the deviation between the two axes is small.

Here, in order to reduce the coaxiality of the needle and the nozzle throat when finally assembled,
1) The coaxiality of the hole into which the nozzle is press-fitted and the hole into which the guide is press-fitted in the body,
2) In the nozzle, the concentricity between the portion to be pressed into the body and the throat,
3) The concentricity of the portion of the guide that is press-fitted into the body and the hole that guides the needle,
4) Assembly coaxiality when the nozzle is press-fitted into the body,
5) Assembly coaxiality when the guide is press-fitted into the body,
5 items must be managed.

  As described above, there are many items to be managed in production, and there is a problem that it is difficult to reduce the coaxiality between the needle and the nozzle throat, or the cost is increased.

  An object of the present invention is to obtain an ejector that adjusts the passage area of a nozzle throat with a needle and has high accuracy in coaxiality between the needle and the nozzle throat.

  In order to achieve the above object, in the first aspect of the present invention, the cylindrical nozzle (2) in which the throat portion (23) having the smallest passage area is formed in the driving fluid passage (21) extending in the axial direction is provided. An ejector that sucks suction fluid by energy exchange when ejecting dynamic fluid from the nozzle (2), is disposed in the drive fluid passage (21), and is displaced in the axial direction to move the throat (23) The needle (3) for adjusting the passage area, the guide (4) in which the needle (3) is slidably held and the needle feed mechanism (42) is formed, and the needle is driven by the feed mechanism (42) Drive means (5, 8), and the guide (4) is fitted into the cylindrical portion of the nozzle (2).

According to this, in order to fit the guide to the nozzle, the management item to reduce the coaxiality of the needle and throat is
1) The concentricity of the hole and the throat where the guide is fitted in the nozzle,
2) The concentricity of the hole that guides the needle and the portion of the guide that is fitted to the nozzle,
3) Assembly coaxiality when fitting the guide to the nozzle,
It becomes three items.

  As described above, the management items for reducing the coaxiality between the needle and the throat can be reduced to three items from the conventional five items. Therefore, the inspection process and the like are simplified, and the cost can be reduced.

  Moreover, if the control value of the coaxiality between the needle and the throat when assembled is the same as the conventional one, it is possible to reduce the tolerance of the coaxiality of a single component, so that the cost of the component can be reduced. .

  Furthermore, if the tolerance of each coaxiality is set to be equal to the conventional one, the coaxiality between the needle and the throat when assembled is smaller than that of the conventional one, so that wear due to sliding between the nozzle and the needle is less likely to occur. . Therefore, it is not necessary to use a material with excellent wear resistance for the nozzle and needle. For example, the material of the nozzle and needle can be changed to a cheap and easy-to-process material to reduce the material cost and processing cost. it can.

  In addition, the yield can be improved by reducing the number of management items.

  As in the invention described in claim 2, in the ejector described in claim 1, the guide (4) can be press-fitted into the nozzle from the end opening opposite to the throat (23) of the nozzle.

  As in the invention described in claim 3, in the ejector described in claim 2, the guide (4) includes a cylindrical portion that is press-fitted into the nozzle, and extends from the cylindrical portion, so that the feed mechanism (42) is provided. And a protrusion having a male screw (42) formed thereon.

  As in the invention according to claim 4, in the ejector according to any one of claims 1 to 3, the nozzle (2) may be a plug nozzle whose passage area decreases toward the nozzle outlet. .

  According to a fifth aspect of the present invention, in the ejector according to any one of the first to fourth aspects, the end opening of the nozzle (2) opposite to the throat (23) is covered with a guide and a needle. In addition, the cylindrical side wall of the nozzle (2) has a communication hole (22) for introducing the driving fluid into the driving fluid passage (21).

  According to this, the driving fluid can be guided to the driving fluid passage through the communication hole.

  According to a sixth aspect of the present invention, in the ejector according to the fifth aspect, the tubular body (1) further includes a nozzle (2) and a driving fluid inlet (10) for introducing the driving fluid. ), And the drive fluid inlet (10) and the communication hole (22) communicate with each other through an annular gap formed between the body (1) and the nozzle (2).

  According to this, the driving fluid introduced into the driving fluid inlet of the body can be guided to the driving fluid passage in the nozzle through the annular gap and the communication hole.

  The invention according to claim 7 further includes a cylindrical body (1) having a drive fluid inlet (10) for accommodating the nozzle (2) therein and introducing the drive fluid, the nozzle (2), The ejector according to any one of claims 1 to 4, wherein the body (1) is integrally formed of one material.

  According to this, the number of parts can be reduced.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of the ejector according to the first embodiment, and FIG. 2 is a cross-sectional view schematically showing an enlarged main part of the ejector of FIG.

  The ejector of this embodiment is used for a refrigeration cycle. The ejector can be used, for example, as a decompression device. As shown in FIG. 1 and FIG. 2, the body 1 is made of a non-cylindrical stainless steel body, and has a driving fluid inlet 10 into which a high-pressure refrigerant flows, a suction fluid inlet 11 into which a gas-phase refrigerant flows, It has a fluid outlet 12 through which high-pressure refrigerant and gas-phase refrigerant mix and flow out. The body 1 has a function as a housing that supports a component as an ejector. A driving fluid inlet 10 and a suction fluid inlet 11 are provided on the side wall surface of the body 1 having a substantially cylindrical shape. A fluid outlet 12 is provided at one end side opening of the body 1. The other end side opening of the body 1 is provided with a member as a lid for closing the opening, and an electric motor as a driving device for driving the needle is disposed on the lid. The high-pressure refrigerant corresponds to the driving fluid of the present invention, and the gas-phase refrigerant corresponds to the suction fluid of the present invention.

  A driving fluid tube 100 that guides high-pressure refrigerant from a radiator (not shown) is connected to the driving fluid inlet 10, and a suction fluid tube 110 that guides a gas-phase refrigerant from an evaporator (not shown) is connected to the suction fluid inlet 11. It is connected. Connected to the fluid outlet 12 is a diffuser 120 that converts the velocity energy of the mixed refrigerant into pressure energy to increase the pressure of the refrigerant. The driving fluid tube 100, the suction fluid tube 110, and the diffuser 120 are brazed to the body 1.

  On one end side in the axial direction of the body 1, three cylindrical holes 13, 14, 15 having a small diameter in order from one end side are formed. A cylindrical nozzle 2 made of stainless steel is inserted into the holes 13, 14, and 15. More specifically, the nozzle 2 is press-fitted into the hole 15 having the smallest diameter among the three holes 13, 14, 15 of the body 1.

  The nozzle 2 converts the pressure energy of the inflowing high-pressure refrigerant into velocity energy, and decompresses and expands the refrigerant in an isentropic manner. The nozzle 2 includes a cylindrical hole 20 extending in the axial direction, and the hole 20. A driving fluid passage 21 that is an internal space and a communication hole 22 that communicates the driving fluid passage 21 with the driving fluid inlet 10 of the body 1 are formed. A driving fluid passage 21 extending in the axial direction in the nozzle 2 is formed with a throat portion 23 having the smallest passage area. The drive fluid inlet 10 and the communication hole 22 communicate with each other through an annular gap formed between the body 1 and the nozzle 2. The outer peripheral surface outside the throat, which is in the vicinity of the tip of the nozzle 2, is fixed to the inner wall surface in the body 1 without any gaps, and divides the body 1 into a driving fluid chamber and a suctioned fluid chamber. A driving fluid inlet 10 communicates with the driving fluid chamber, and a suction fluid inlet 11 communicates with the suctioned fluid chamber. Of the openings at both ends of the nozzle 2, the end opening opposite to the throat 23 is covered with a guide and a needle, and is defined by the body 1 and the can 7 and communicates with the driving fluid inlet 10. Is arranged.

  In the present embodiment, in order to accelerate the speed of the refrigerant ejected from the nozzle 2 to the speed of sound or more, a substantial refrigerant passage cross-sectional area is present in the throat portion 23 where the passage area is most reduced in the middle of the passage and in the throat portion 23 and thereafter. A Laval nozzle (see Fluid Engineering (The University of Tokyo Press)) with a nozzle diffuser set to gradually expand is used.

  When processing the nozzle 2 alone, the hole 20 is processed based on the throat 23, or the throat 23 is processed based on the hole 20.

  In the driving fluid passage 21 of the nozzle 2, a metal needle 3 that is displaced in the axial direction of the driving fluid passage 21 and adjusts the passage area of the throat 23 is disposed. The needle 3 heads toward the distal end side in order to change the passage area of the large-diameter cylindrical portion 30 held by the guide 4 described later, the small-diameter cylindrical portion 31 provided with the spring 130 described later, and the throat portion 23. And a conical portion 32 formed in a conical shape so that the cross-sectional area is reduced.

  The guide 4 is made of metal and has a stepped cylindrical shape. The large-diameter cylindrical portion 40 of the guide 4 is press-fitted into the hole 20 of the nozzle 2. A small diameter cylindrical portion 41 of the guide 4 protrudes from the nozzle 2, and a male screw 42 is formed on the small diameter cylindrical portion 41. A cylindrical guide hole 43 that slidably holds the needle 3 is formed at the center of the guide 4.

  When processing the guide 4 alone, the guide hole 43 is processed based on the large diameter cylindrical portion 40 or the large diameter cylindrical portion 40 is processed based on the guide hole 43.

  The guide 4 includes a cylindrical portion that is fitted and fixed to the nozzle 2 and a protruding portion that extends from the cylindrical portion and has a male screw 42 that is a feed screw mechanism as a feed mechanism of the needle 3. The guide 4 is fitted to the nozzle 2 from the end opening opposite to the throat 23 of the nozzle 2. The guide 4 can be fitted to an inner peripheral cylindrical surface as a reference surface of the nozzle 2 or an outer peripheral cylindrical surface. For example, the guide 4 can be fitted to the surface of the throat 23 to be adjusted by the needle 3 as a processing reference. Furthermore, the surface provided on the guide 4 for positioning and guiding the needle 3 can be processed with reference to the fitting surface of the guide 4 with the nozzle 2. For example, the hole 20 which is the inner peripheral cylindrical surface of the nozzle 2 can be used as the reference surface. In this case, the guide hole 43 of the guide 4 can be processed using the outer peripheral cylindrical surface of the guide 4 as a reference. Then, the outer peripheral cylindrical surface of the guide 4 can be fitted into the inner peripheral cylindrical surface of the nozzle 2 by a technique such as press fitting.

  The rotor 5 is made of a magnetic metal and has a substantially cup shape. Then, the spring 130 is disposed in the small diameter cylindrical portion 31 of the needle 3, the small diameter cylindrical portion 31 is inserted into the hole 51 in the bottom 50 of the rotor 5, and the washer 6 is welded to the portion protruding from the hole 51 in the small diameter cylindrical portion 31. is doing. As a result, the relative position between the needle 3 and the rotor 5 remains unchanged unless a forcible force for contracting or extending the spring 130 is applied. The rotor 5 and the needle 3 are connected to each other in the axial direction and the radial direction between the shoulder portion formed on the needle 3 and the rotor 5 under the biasing force of the spring 130 disposed in a contracted state. It is assumed that the relative position is slightly adjustable. The position of the needle 3 is determined by the guide 4 in the axial direction and the radial direction.

  A female screw 53 as a part of the feed mechanism of the needle 3 or a part of the drive mechanism is formed in the cylindrical portion 52 of the rotor 5, and the female screw 53 is screwed to the male screw 42 of the guide 4. Thus, when the rotor 5 is rotated, the rotor 5 and the needle 3 are moved in the axial direction.

  A cup-shaped can 7 made of non-magnetic metal that covers the rotor 5 is welded to one end of the body 1 in the axial direction.

  A coil 8 of a stepping motor is disposed on the outer peripheral side of the rotor 5 and the can 7. The coil 8 is fitted to the can 7 and is assembled to the driving fluid tube 100 or the body 1 by a clip (not shown) or the like. In this embodiment, a feed screw mechanism is adopted as the feed mechanism of the needle 3, and a male screw 42, which is a part of the screw, is formed integrally with the guide 4. As the drive mechanism for driving the needle 3 in the axial direction by the feed mechanism, a stepping motor as a rotating electric machine is employed. The rotor 5 as a part of the drive mechanism is integrally formed with a female screw 53 that is a part of the feed mechanism. The female screw 53 can be formed as a separate member from the rotor 5 and can be connected to transmit rotational force. The drive mechanism includes a rotor 5 and a coil 8.

  When a magnetic force is generated by the coil 8, the rotor 5 is rotated by an induced electromotive force. As the rotor 5 rotates, the rotor 5 and the needle 3 move in the axial direction.

Since the ejector of this embodiment press-fits the guide 4 into the nozzle 2, the management item for reducing the coaxiality between the needle 3 and the throat 23 of the nozzle 2 is
1) In the nozzle 2, the coaxiality between the hole 20 into which the guide 4 is press-fitted and the throat 23,
2) In the guide 4, the coaxiality of the large diameter cylindrical portion 40 press-fitted into the nozzle 2 and the guide hole 43 for guiding the needle 3,
3) Assembly coaxiality when the guide 4 is press-fitted into the nozzle 2,
It becomes three items.

  Thus, the management items for reducing the coaxiality between the throat portion 23 of the needle 3 and the nozzle 2 can be reduced to three items from the conventional five items. Therefore, the inspection process and the like are simplified, and the cost can be reduced.

  Moreover, if the coaxiality management value of the needle 3 and the throat 23 when assembled is equivalent to the conventional one, the coaxiality of a single component (for example, the coaxiality of the large-diameter cylindrical portion 40 and the guide hole 43 in the guide 4). Since it is possible to relax the tolerance of the parts, it is possible to reduce the cost of parts.

  Furthermore, if the tolerance of each coaxiality is set to be equal to the conventional one, the coaxiality between the needle 3 and the throat 23 when assembled is smaller than the conventional one. Less likely to occur. Therefore, the nozzle 2 and the needle 3 do not need to use a material having excellent wear resistance. For example, the material of the nozzle 2 or the needle 3 is changed to a cheap and easy-to-process material, thereby reducing the material cost and the processing cost. Can be reduced.

  In addition, the yield can be improved by reducing the number of management items.

(Second Embodiment)
A second embodiment of the present invention will be described. FIG. 3 is a cross-sectional view showing a main part of an ejector according to the second embodiment. The same or equivalent parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the first embodiment, a Laval nozzle is used as the nozzle 2, but in this embodiment, a plug nozzle is used as the nozzle 2.

  As shown in FIG. 3, the nozzle 2 of the present embodiment has a shape that does not have a divergent portion after the throat portion 23, and more specifically, a conical shape in which the passage area decreases toward the nozzle outlet. A tapered taper is formed. Further, the needle 3 protrudes from the nozzle 2.

  The ejector of this embodiment can obtain the same effects as those of the first embodiment.

(Third embodiment)
A third embodiment of the present invention will be described. FIG. 4 is a cross-sectional view showing a main part of an ejector according to the third embodiment. The same or equivalent parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the first embodiment, the body 1 and the nozzle 2 are integrated by press-fitting. However, as shown in FIG. 4, the guide 4 is press-fitted into the body 1 and the nozzle 2 that are integrally formed of one material. It may be.

  The ejector of this embodiment can obtain the same effects as those of the first embodiment. Further, by forming the body 1 and the nozzle 2 integrally, the number of parts can be reduced.

It is sectional drawing of the ejector which concerns on 1st Embodiment of this invention. It is sectional drawing which expands and shows typically the principal part of the ejector of FIG. It is sectional drawing which shows the principal part of the ejector which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the principal part of the ejector which concerns on 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Body, 2 ... Nozzle, 3 ... Needle, 4 ... Guide, 5 ... Rotor 5, 8 ... Coil (drive means), 10 ... Drive fluid inlet, 21 ... Drive fluid passage, 23 ... Throat part, 42 ... Male screw .

Claims (7)

A cylindrical nozzle (2) having a throat portion (23) with the smallest passage area formed in an axially extending drive fluid passage (21),
In an ejector that sucks suction fluid by an energy exchange action when jetting drive fluid from the nozzle (2),
A needle (3) disposed in the drive fluid passage (21) and axially displaced to adjust the passage area of the throat (23);
A guide (4) in which the needle (3) is slidably held and a feed mechanism (42) for the needle is formed;
Drive means (5, 8) for driving the needle by the feed mechanism (42),
The ejector according to claim 1, wherein the guide (4) is fitted in a cylindrical portion of the nozzle (2). The ejector according to claim 1, wherein the guide (4) is press-fitted into the nozzle from an end opening opposite to the throat (23) of the nozzle. The guide (4) includes a cylindrical portion that is press-fitted into the nozzle, and a protruding portion that extends from the cylindrical portion and has a male screw (42) as the feed mechanism (42). The ejector according to claim 2, wherein The ejector according to any one of claims 1 to 3, wherein the nozzle (2) is a plug nozzle whose passage area decreases toward the nozzle outlet. The end opening of the nozzle (2) opposite to the throat (23) is covered with the guide and the needle,
The cylindrical side wall of the nozzle (2) has a communication hole (22) for introducing a driving fluid into the driving fluid passage (21), according to any one of claims 1 to 4. Ejector. Furthermore, the nozzle (2) is accommodated therein, and a cylindrical body (1) having a driving fluid inlet (10) for introducing a driving fluid is provided, and the body (1) and the nozzle (2) The ejector according to claim 5, wherein the driving fluid inlet (10) and the communication hole (22) communicate with each other through an annular gap formed therebetween. Furthermore, the nozzle (2) is accommodated therein, and a cylindrical body (1) having a driving fluid inlet (10) for introducing a driving fluid is provided. The nozzle (2) and the body (1) are 1 The ejector according to claim 1, wherein the ejector is integrally formed of two materials.

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