JPS6325466A - Control mechanism of evaporator-outlet pressure in refrigeration cycle - Google Patents

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は蒸発器と圧縮機とを繋ぐ吸入管路に介在させて
吸入絞り弁を設け、冷房負荷が減少した場合においてこ
の吸入絞り弁によって蒸発器出口部分の圧力を一定圧力
以上に保持する事によって同蒸発器に対する霜付きを防
止する様に設けられる蒸発器出口圧力の制御機構に関す
る。[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a suction throttle valve interposed in the suction pipe connecting the evaporator and the compressor, and when the cooling load decreases, the suction throttle valve The present invention relates to an evaporator outlet pressure control mechanism provided to prevent frost formation on the evaporator by maintaining the pressure at the evaporator outlet above a certain pressure.

〔従来の技術〕[Conventional technology]

一般に車輌空調用の冷凍サイクルにあっては車室内の冷
房負荷が減少した場合において蒸発器と圧縮機とを繋ぐ
吸入管路において同蒸発器の出口側の圧力が低下するの
に伴い同蒸発器に霜（フロスト）が付着するという不具
合を生ずる事となる。Generally, in a refrigeration cycle for vehicle air conditioning, when the cooling load inside the vehicle decreases, the pressure on the outlet side of the evaporator decreases in the suction pipe connecting the evaporator and the compressor. This will cause problems such as frost adhering to the surface.

そして従来、この様な不具合の解決策として蒸発器と圧
縮機とを繋ぐ吸入管路に介在させて吸入絞り弁を設け、
冷房負荷が減少した場合において蒸発器より圧縮機に向
けて送り込まれる冷媒ガス（吸入ガス）のその送り量（
吸入ガス量）をコントロールする事によって、そしてこ
の様に蒸発器より圧縮機に向けて送り込まれる冷媒ガス
（吸入ガス）のその送り量（吸入ガス量）をコントロー
ルする事によって蒸発器出口部分の圧力を常時一定圧力
以上に保持する事によって同蒸発器に対する霜付きを防
止する方法が提案されている。Conventionally, as a solution to such problems, a suction throttle valve was installed in the suction pipe connecting the evaporator and compressor.
The amount of refrigerant gas (suction gas) sent from the evaporator to the compressor when the cooling load decreases (
By controlling the amount of refrigerant gas (suction gas) sent from the evaporator to the compressor, the pressure at the outlet of the evaporator can be reduced by controlling the amount of refrigerant gas (suction gas) sent from the evaporator to the compressor. A method has been proposed to prevent frost from forming on the evaporator by maintaining the pressure above a certain level at all times.

第７図はその具体的構造を表わす図面であって、蒸発器
９Ａの出口側の開口部より吸入管路］０が延設され、そ
の先端部は圧縮機２の吸入フランジに連結される。そし
て同吸入管路１０にはその任意の中間部に位置して吸入
絞り弁１１が介在させて設けられ、同吸入絞り弁１１に
は蒸発器９Ａ側の開口部と対向させてスプール弁１４が
進退自在に嵌挿される。更に詳しくは同スプール弁１４
のボトム側の一端には大気と連通ずる圧力室４１（大気
圧力室）が設けられ、且つ、同大気圧力室４１にはばね
４２が介装される一方、同スプール弁１４のヘッド側の
一端にはベローズ４３を介して吸入管路１０と連通ずる
圧力室４４（吸入圧力室）が対峙させて設けられ、面圧
力室４１．４４間に生ずる差圧の変化を介して進退作用
が得られる様に設けられる。即ち、車室内の冷房負荷が
大きい状態においては蒸発器９Ａの出口側の圧力（絞り
前吸入圧力）が高い圧力状態にある事により、吸入絞り
弁１１において上記蒸発器９Ａの出口側と連通ずる吸入
圧力室４４内の圧力（吸入絞り前吸入圧力と同一圧力）
と大気圧力室４１内の圧力（大気圧＋ばね４２の付勢圧
）との間に大きな圧力差が生じ、この圧力差を介してス
プール弁１４が吸入管路１０を大きく開く状態が得られ
、又、車室内の冷房負荷が小さい状態においては蒸発器
９Ａの出口側の圧力（絞り前吸入圧力）が低下して吸入
圧力室４４内の圧力が大気圧力室４１内の圧力を下回る
事により、スプール弁１４が吸入管路１０を狭める状態
（吸入ガス量を減らす状態）が得られる様に設けられる
。FIG. 7 is a drawing showing the specific structure of the evaporator 9A, in which a suction pipe 0 extends from an opening on the outlet side of the evaporator 9A, and its tip is connected to the suction flange of the compressor 2. The suction pipe line 10 is provided with a suction throttle valve 11 interposed at an arbitrary intermediate portion thereof, and the suction throttle valve 11 has a spool valve 14 facing the opening on the evaporator 9A side. It is inserted so that it can move forward and backward. For more details, see spool valve 14.
A pressure chamber 41 (atmospheric pressure chamber) communicating with the atmosphere is provided at one end on the bottom side of the spool valve 14 , and a spring 42 is interposed in the atmospheric pressure chamber 41 . A pressure chamber 44 (suction pressure chamber) communicating with the suction pipe line 10 via a bellows 43 is provided facing each other, and an advancing and retracting action is obtained through a change in the differential pressure generated between the surface pressure chambers 41 and 44. It is set up as follows. That is, when the cooling load in the vehicle interior is large, the pressure on the outlet side of the evaporator 9A (suction pressure before throttling) is in a high pressure state, so that the suction throttle valve 11 communicates with the outlet side of the evaporator 9A. Pressure inside the suction pressure chamber 44 (same pressure as the suction pressure before suction throttling)
A large pressure difference occurs between the pressure inside the atmospheric pressure chamber 41 (atmospheric pressure + the biasing pressure of the spring 42), and the spool valve 14 opens the suction pipe 10 widely through this pressure difference. Also, when the cooling load inside the vehicle is small, the pressure on the outlet side of the evaporator 9A (suction pressure before throttling) decreases, and the pressure in the suction pressure chamber 44 becomes lower than the pressure in the atmospheric pressure chamber 41. , the spool valve 14 is provided so as to narrow the suction pipe 10 (reduce the amount of suction gas).

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

しかして上記の様な蒸発器出口圧力の制御機構にあって
は、蒸発器９Ａ出口の圧力（絞り前圧力）変化を介して
スプール弁１４を進退移動させる様に設けられているた
めに原理的に蒸発器９Ａ出口の圧力（絞り前圧力）を一
定圧力に保持する事が出来ない（例えばスプール弁１４
が全開状態から絞り方向に向けて移動し始める時の絞り
前圧力を２ｋｇ／Ｇに設定すれば、スプール弁１４が全
開状態となる時の絞り前圧力を例えば１．６ｋｇ／Ｇの
様に上記圧力よりも低い圧力に設定しなければならない
）点、そしてこの様に蒸発器９Ａ出口の圧力（絞り前圧
力）を一定圧力に保持する事が出来ない事により蒸発器
より車室内に向けて吹き出される冷風の温度を一定温度
に保持する事が出来ない点、即ち、冷風温度の変動幅が
大きくなり車室内の空調フィーリングが損われるという
不具合を生ずる点に第１の問題点を有する。However, in the control mechanism for the evaporator outlet pressure as described above, the spool valve 14 is moved forward and backward through changes in the pressure at the outlet of the evaporator 9A (pre-throttling pressure), so the principle is The pressure at the outlet of the evaporator 9A (pressure before throttling) cannot be maintained at a constant pressure (for example, when the spool valve 14
If the pre-throttling pressure when the spool valve 14 starts to move in the throttle direction from the fully open state is set to 2 kg/G, the pre-throttling pressure when the spool valve 14 becomes fully open will be set to 1.6 kg/G, for example, above. The pressure must be set to a lower value than the actual pressure), and because the pressure at the outlet of the evaporator 9A (pre-throttling pressure) cannot be maintained at a constant pressure, air is blown from the evaporator into the passenger compartment. The first problem is that the temperature of the cooled air cannot be maintained at a constant temperature, that is, the range of fluctuation in the temperature of the cooled air becomes large, resulting in a problem that the air conditioning feeling inside the vehicle is impaired.

又、上記の様な吸入絞り弁機構にあっては、圧縮機の起
動時においてスプール弁１４は全開状態にある事により
、起動と同時に１００％稼動の状態となってしまう点、
即ち、圧縮機の起動時における立ち上がりショックを緩
和する事が出来ない点に第２の問題点を有する。In addition, in the suction throttle valve mechanism as described above, the spool valve 14 is fully open when the compressor is started, so it becomes 100% operating at the same time as the start.
That is, the second problem is that the start-up shock at the time of starting the compressor cannot be alleviated.

本発明は上記の様な問題点を解決する為にその改善を試
みたものであって、蒸発器の出口側の圧力（絞り前吸入
圧力）を一定の圧力に保持した状態にて圧縮機に送り込
まれる吸入ガス量のコントロールを行なう事が出来る様
にする点にその解決すべき問題点を有する。即ち、本発
明は蒸発器の出口側の圧力（絞り前吸入圧力）に設定値
を設け、同設定値を基準としてスプールを進退移動させ
る様にする事によって同蒸発器の出口側の圧力（絞り前
吸入圧力）を常時一定圧力（設定圧力）に保持する事が
出来る様にした事を特徴とするものであって、その具体
的な手段と作用は次の通りである。The present invention is an attempt to improve the above-mentioned problems.The present invention is an attempt to improve the above-mentioned problems. The problem to be solved lies in the ability to control the amount of suction gas fed. That is, the present invention provides a set value for the pressure on the outlet side of the evaporator (suction pressure before throttling), and moves the spool forward and backward based on the set value, thereby increasing the pressure on the outlet side of the evaporator (suction pressure before throttling). It is characterized by being able to maintain the pre-suction pressure at a constant pressure (set pressure) at all times, and its specific means and effects are as follows.

〔問題点を解決するための手段〕[Means for solving problems]

蒸発器と圧縮機とを繋ぐ吸入管路に介在させて吸入絞り
弁を進退自在に設け、同吸入絞り弁を蒸発器出口の設定
圧力を基準として開閉させる様にする。即ち、 ■　蒸発器出口の圧力が設定圧力を上回る状態において
は上記吸入絞り弁を後退させて吸入管路を大きく開く開
く状態が得られる様にする。A suction throttle valve is provided in the suction pipe connecting the evaporator and the compressor so as to be able to move forward and backward, and the suction throttle valve is opened and closed based on the set pressure at the outlet of the evaporator. That is, (1) When the pressure at the evaporator outlet exceeds the set pressure, the suction throttle valve is moved back to widen the suction pipe.

■　蒸発器出口の圧力が設定圧力を下回る状態において
は吸入絞り弁を前進させて吸入管路を閉塞する状態が得
られる様にする。(2) When the pressure at the evaporator outlet is lower than the set pressure, move the suction throttle valve forward to close the suction pipe.

〔作　用〕[For production]

吸入絞り弁が蒸発器出口の設定圧力を基準として開閉す
る事により、同蒸発器出口の圧力を常時一定圧力（設定
圧力）に保持する事が出来る。By opening and closing the suction throttle valve based on the set pressure at the evaporator outlet, the pressure at the evaporator outlet can be maintained at a constant pressure (set pressure) at all times.

〔実施例〕〔Example〕

以下に本発明の具体的な実施例を例示の図面について説
明する。Specific embodiments of the present invention will be described below with reference to illustrative drawings.

第１図と第２図に表わす第１の実施例において、第１図
は冷凍サイクルの概略を表わす図面であって、同概略図
において１はエンジン、２は圧縮機を示す。エンジン１
と圧縮機はベルト伝導機構３及び電磁クラッチ４によっ
て連結され、同ベルト伝導機構３及び電磁クラッチ４を
介してエンジン１の回転を圧縮機２に伝達する事が可能
な如く設けられる。圧縮機２の吐出室からは吐出管路５
が延設され、同吐出管路５に沿って凝縮機６、冷媒液タ
ンク（レシーバ）７、膨張弁８、冷却ユニット９が直列
させて設けられる。冷却ユニット９は蒸発器９Ａと送風
機９Ｂより成り、同冷却ユニット９からは蒸発器９Ａの
出口より吸入管路１０が延設される。同吸入管路１０は
その先端部が圧縮機２の吸入室と連通ずる如く設けられ
、同吸入管路１０には同吸入管路１０の開口面積を調整
すべく吸入絞り弁１１が設けられる（以後吸入絞り弁＝
７− １１と蒸発器９Ａ間を繋ぐ吸入管路を［絞り前吸入管路
１０ＡＪ、吸入絞り弁１１と圧縮機２間を繋ぐ吸入管路
を「絞り後吸入管路１０Ｂ」という）。しかして同吸入
絞り弁１１において、１２は絞り前吸入管路１０Ａと対
向させて穿設するボアであって、同ボア１２は蒸発器９
Ａの出口側に開口部を存して有底円筒状に形成される。In the first embodiment shown in FIGS. 1 and 2, FIG. 1 is a diagram schematically showing a refrigeration cycle, and in the schematic diagram, 1 indicates an engine and 2 indicates a compressor. engine 1
The compressor and the compressor are connected by a belt transmission mechanism 3 and an electromagnetic clutch 4, and the rotation of the engine 1 can be transmitted to the compressor 2 via the belt transmission mechanism 3 and the electromagnetic clutch 4. A discharge pipe line 5 is connected from the discharge chamber of the compressor 2.
A condenser 6, a refrigerant liquid tank (receiver) 7, an expansion valve 8, and a cooling unit 9 are provided in series along the discharge pipe 5. The cooling unit 9 consists of an evaporator 9A and a blower 9B, and a suction pipe 10 extends from the cooling unit 9 from the outlet of the evaporator 9A. The suction pipe 10 is provided so that its tip communicates with the suction chamber of the compressor 2, and a suction throttle valve 11 is provided in the suction pipe 10 to adjust the opening area of the suction pipe 10. From now on, suction throttle valve =
The suction pipe connecting between 7-11 and the evaporator 9A is called the "pre-throttling suction pipe 10AJ," and the suction pipe connecting between the suction throttle valve 11 and the compressor 2 is called the "post-throttling suction pipe 10B." In the suction throttle valve 11, reference numeral 12 denotes a bore that is bored facing the pre-throttling suction pipe 10A, and the bore 12 is connected to the evaporator 9.
It has an opening on the exit side of A and is formed into a cylindrical shape with a bottom.

そして同ボア１２にはボトム側に圧力室１３を存してス
プール弁１４が進退自在に嵌挿される。そして又、同ス
プール弁１４のヘッド側の一端にばばね受は座１５が形
成されると共にボア１２の開口部には同ばね受は座１５
と対面させてばね受は座１６が形成される。そして上記
面ばね受は座１５．１６間にばばね１７が介装され、同
ばね１７により上記スプール弁１４は常時はボｌ〜ム側
（圧力室１３側）に向けて付勢された状態にある様に設
けられる。The bore 12 has a pressure chamber 13 on the bottom side, into which a spool valve 14 is fitted so as to be movable forward and backward. Further, a spring bearing seat 15 is formed at one end of the head side of the spool valve 14, and a spring bearing seat 15 is formed at the opening of the bore 12.
A seat 16 is formed in the spring receiver so as to face the spring receiver. A spring 17 is interposed between the seats 15 and 16 of the surface spring receiver, and the spool valve 14 is normally biased toward the volume side (pressure chamber 13 side). It is set up as shown in

一方、圧力室１３からは導圧路１８が延設されると共に
同導圧路１８は吸入圧力の導圧路１８Ａと吐出圧力の導
圧路１８Ｂに分岐され、吸入圧力の導圧路１８Ａの先端
部は圧縮機２の吸入室若しくは絞り後吸入管路１０Ｂと
、又、吐出圧力の導圧路１８Ｂの先端部は圧縮機２の吐
出室若しくは吐出管路５と夫々連通ずる如く設けられる
。そして吸入圧力の導圧路１８Ａと吐出圧力の導圧路１
８Ｂには夫々電磁弁１９Ａ、１９Ｂが取り付けられ、両
電磁弁１９Ａ、１９Ｂは予め設定された蒸発器９Ａ出口
の圧力（設定圧力）を基準として選択的に開閉する事が
出来る様に設けられる。即ち、車室内の温度、蒸発器９
Ａより吹き出される冷却風の温度、蒸発器９Ａ出口の圧
力若しくは温度等を介して蒸発器９Ａ出口の圧力（絞り
前圧力）の変化を検知し、同蒸発器９Ａ出口の圧力（絞
り前圧力）が設定圧力を上回る状態においては吸入圧力
の導圧路１８Ａ側に取り付けられる電磁弁１９Ａを開き
（吐出圧力の導圧路１８Ｂ側に取り付けられる電磁弁１
９Ｂを閉じる）、又、蒸発器９Ａ出口の圧力（絞り前圧
力）が設定圧力を下回る状態においては吐出圧力の導圧
路１８Ｂ側に取り付けられる電磁弁１９Ｂを開く（吸入
圧力の導圧路１８Ａ側に取り付けられる電磁弁１９Ａを
閉じる）−９＝ 状態が得られる様に設けられる。前記電磁弁１９Ａ、１
９Ｂの作動切換え制御は圧力と設定値との比較において
行なう如く詳述したが、蒸発器９Ａ出口の圧力、温度、
冷却風温度等の冷房負荷を検知する信号を一つ選び、そ
れに設定値を設けてその比較において切換え制御を行な
ってもよい。On the other hand, a pressure channel 18 is extended from the pressure chamber 13, and the pressure channel 18 is branched into a pressure channel 18A for suction pressure and a pressure channel 18B for discharge pressure. The distal end of the compressor 2 is provided to communicate with the suction chamber or the post-throttling suction line 10B, and the distal end of the discharge pressure guide line 18B is communicated with the discharge chamber of the compressor 2 or the discharge conduit 5, respectively. Then, a pressure guide path 18A for suction pressure and a pressure guide path 1 for discharge pressure.
Solenoid valves 19A and 19B are respectively attached to 8B, and both solenoid valves 19A and 19B are provided so that they can be selectively opened and closed based on a preset pressure (set pressure) at the outlet of the evaporator 9A. That is, the temperature inside the vehicle, the evaporator 9
Changes in the pressure at the outlet of the evaporator 9A (pressure before throttling) are detected through the temperature of the cooling air blown out from A, the pressure or temperature at the outlet of the evaporator 9A, and the pressure at the outlet of the evaporator 9A (pressure before throttling) is detected. ) exceeds the set pressure, the solenoid valve 19A installed on the suction pressure pressure path 18A side is opened (the solenoid valve 19A installed on the discharge pressure pressure path 18B side is opened).
9B), and when the pressure at the outlet of the evaporator 9A (pre-throttling pressure) is lower than the set pressure, the solenoid valve 19B installed on the discharge pressure pressure path 18B side is opened (the suction pressure pressure path 18A is closed). (Close the electromagnetic valve 19A attached to the side)-9= condition is provided. The solenoid valve 19A, 1
The operation switching control of 9B has been described in detail as being performed by comparing the pressure with a set value, but the pressure, temperature, and
It is also possible to select one signal for detecting a cooling load such as cooling air temperature, provide a set value for it, and perform switching control based on the comparison.

しかして上記実施例において車室内の冷房負荷が大きい
状態においては、蒸発器９Ａの出口において予め設定さ
れた圧力（設定圧力）よりも高い圧力が得られた状態に
ある事により、そしてこの様に蒸発器９Ａの出口が設定
圧力よりも高い圧力状態にあることが車室内の温度、蒸
発器９Ａより吹き出される冷却風の温度、同蒸発器９Ａ
出口の圧力若しくは温度等をセンサーとして検出される
事により、同検出信号を介して吸入圧力の導圧路１８Ａ
側に取り付けられる電磁弁１９Ａを開き、吐出圧力の導
圧路１８Ｂ側に取り付けられる電磁弁１９Ｂを閉じる状
態、即ち、吸入圧力を圧力室１３に送り込む状態が得ら
れる。そしてこの様に圧力室１３に対して吸入圧力が送
り込まれる事により、同圧力室１３内の圧力（吸入圧力
状態）よりも絞り前吸入管路１０Ａ側の圧力（絞り前吸
入圧力＋ばねの付勢圧）が打ち勝ってスプール弁１４を
圧力室１３方向に向けて後退させる作用、即ち、吸入管
路１０を大きく開く状態が得られる。However, in the above embodiment, when the cooling load inside the vehicle is large, a pressure higher than the preset pressure (set pressure) is obtained at the outlet of the evaporator 9A, and thus The fact that the pressure at the outlet of the evaporator 9A is higher than the set pressure indicates the temperature inside the vehicle, the temperature of the cooling air blown out from the evaporator 9A, and the temperature of the cooling air blown out from the evaporator 9A.
By detecting the outlet pressure or temperature as a sensor, the suction pressure is connected to the pressure guide path 18A via the detection signal.
A state is obtained in which the solenoid valve 19A attached to the side is opened and the solenoid valve 19B attached to the discharge pressure pressure guide path 18B is closed, that is, a state is obtained in which suction pressure is sent into the pressure chamber 13. By feeding the suction pressure into the pressure chamber 13 in this way, the pressure on the pre-throttling suction pipe 10A side (pre-throttling suction pressure + spring attachment) is lower than the pressure inside the pressure chamber 13 (suction pressure state). (pressure) overcomes the pressure and causes the spool valve 14 to retreat toward the pressure chamber 13, that is, a state in which the suction pipe 10 is wide open is obtained.

又、車室内の冷房負荷が減少して蒸発器９Ａの出口圧力
が設定圧力を下回った状態において、この設定圧力を下
回った状態が上記と同様車室内の温度、蒸発器９Ａより
吹き出される冷却風の温度、同蒸発器９Ａ出口の圧力若
しくは温度等をセンサーとして検出され、同検出信号を
介して吸入圧力の導圧路１．８Ａ側に取り付けられる電
磁弁１９Ａを閉じ、吐出圧力の導圧路１８Ｂ側に取り付
けられる電磁弁１．９Ｂを開く状態、即ち、吐出圧力を
圧力室１３に送り込む状態が得られる。そしてこの様に
圧力室１３に対して吐出圧力が送り込まれる事により、
同圧力室１３内の圧力（吐出圧力状態）が絞り前吸入管
路１．ＯＡ側の圧力（絞り前吸入圧力＋ばねの付勢圧）
に打ち勝ってスプール弁１４を絞り前吸入管路１０Ａ方
向に向けて押し出す作用、即ち、吸入管路１０の開１１
面積が狭められて吸入ガスの流量を制限する作用が得ら
れ、此により蒸発器９Ａの出口圧力が一定圧力（設定圧
力）に保持される。In addition, when the cooling load in the vehicle interior decreases and the outlet pressure of the evaporator 9A falls below the set pressure, the state in which the outlet pressure of the evaporator 9A is lower than the set pressure corresponds to the temperature in the vehicle interior and the cooling blown out from the evaporator 9A as described above. The temperature of the air, the pressure or temperature at the outlet of the evaporator 9A, etc. are detected by a sensor, and based on the detection signal, the solenoid valve 19A attached to the suction pressure pressure path 1.8A side is closed, and the discharge pressure is guided. A state in which the solenoid valve 1.9B attached to the path 18B side is opened, that is, a state in which discharge pressure is sent into the pressure chamber 13 is obtained. By feeding the discharge pressure into the pressure chamber 13 in this way,
The pressure in the pressure chamber 13 (discharge pressure state) is the same as that in the suction pipe 1 before throttling. Pressure on the OA side (suction pressure before throttling + spring biasing pressure)
The action of overcoming the
The area is narrowed to obtain the effect of restricting the flow rate of the suction gas, thereby maintaining the outlet pressure of the evaporator 9A at a constant pressure (set pressure).

第３図と第４図に表わす第２の実施例において、吸入絞
り弁１１にはボトム側にベローズ２０が伸縮自在に設け
られると共に同ベローズ２ｏを間に存して吸入圧力室２
１と大気圧力室２２が対峙させて設けられる。そして吸
入圧力室２１は吸入圧力の導圧路２３を介して絞り前吸
入管路１０Ａと連通ずる如く設けられる一方、大気圧力
室２２は通気口２４を介して大気と連通する如く設けら
れると共にばね２５が介装され、両圧力室２１，２２間
に生ずる圧力差を介して上記ベローズ２０を伸縮させる
事が出来る様に設けられる。そして又、同ベローズ２０
の先端部には吸入圧力室２１に向けて後述するボール弁
２６のプッシャー２７が突設される一方、吸入圧力室２
１側には同プッシャー２７と対面させて弁室２８が形成
され、同弁室２８には前述のボール弁２６が係留される
。更に具体的には同弁室２８には上記プッシャー２７と
対面させて狭搾口２９が開口され、同狭搾口２９を介し
て吸入圧力室２１と弁室２８は相互に連通ずる如＜鰻け
られる。そして同弁室２８には狭搾［１２９部分に弁座
３０が形成され、同弁座３０に対してボール弁２６を当
接させる事が出来る設けられる。そして又、同弁室２８
にはばね３１が介装され、同ばね３１を介して常時は弁
座３０を閉塞する方向に向けて付勢された状態にある様
に設けられる。In the second embodiment shown in FIGS. 3 and 4, a bellows 20 is extendably provided on the bottom side of the suction throttle valve 11, and a bellows 20 is provided between the suction pressure chambers 20 and 20.
1 and an atmospheric pressure chamber 22 are provided facing each other. The suction pressure chamber 21 is provided so as to communicate with the pre-throttling suction pipe 10A via a suction pressure guide path 23, while the atmospheric pressure chamber 22 is provided so as to communicate with the atmosphere via a vent 24, and a spring 25 is interposed so that the bellows 20 can be expanded and contracted through the pressure difference generated between the pressure chambers 21 and 22. And again, the same bellows 20
A pusher 27 of a ball valve 26, which will be described later, protrudes toward the suction pressure chamber 21 at the tip of the suction pressure chamber 2.
A valve chamber 28 is formed on the first side facing the pusher 27, and the aforementioned ball valve 26 is moored to the valve chamber 28. More specifically, a narrow squeeze port 29 is opened in the valve chamber 28 so as to face the pusher 27, and the suction pressure chamber 21 and the valve chamber 28 communicate with each other through the narrow squeeze port 29. I get kicked. A valve seat 30 is formed in the constricted portion 129 of the valve chamber 28, and the ball valve 26 can be brought into contact with the valve seat 30. And also, the same valve chamber 28
A spring 31 is interposed therebetween, and the valve seat 30 is normally biased in the direction of closing the valve seat 30 via the spring 31.

一方、吸入管路１０側には絞り前吸入管路１０Ａと対向
させてボア３２が穿設され、同ボア３２には吐出圧力室
３３とばね室３４を存してスプール弁３５が上記絞り前
吸入管路１０Ａに向けて進退自在に嵌挿される。そして
ばね室３４にばばね３６が介装され、同ばね３６を介し
てスプール弁３５を絞り前吸入管路１０Ａ方向に向けて
付勢する様に設けられると共にスプール弁３５には連通
路３７が穿設され、ばね室３４と絞り前吸入管路１０Ａ
間を相互に連通させる事が出来る様に設けられる。又、
図示省略しであるが吐出管路５より絞り通路が延設され
、その先端部は二叉に分岐される。そしてその一方の絞
り通路３８Ａは吐出圧力室３３に連通し、又、もう一方
の絞り通路３８Ｂは弁室２８に連通ずる如く設けられる
。On the other hand, a bore 32 is bored on the side of the suction pipe 10 facing the pre-throttling suction pipe 10A, and the bore 32 has a discharge pressure chamber 33 and a spring chamber 34, and a spool valve 35 is connected to the pre-throttling suction pipe 10A. It is inserted into the suction pipe 10A so that it can move forward and backward. A spring 36 is interposed in the spring chamber 34, and is provided to bias the spool valve 35 toward the pre-throttling suction pipe 10A through the spring 36, and the spool valve 35 has a communication passage 37. The spring chamber 34 and the pre-throttling suction pipe 10A are bored.
They are provided so that they can communicate with each other. or,
Although not shown, a throttle passage extends from the discharge pipe 5, and its tip is bifurcated into two. One throttle passage 38A communicates with the discharge pressure chamber 33, and the other throttle passage 38B communicates with the valve chamber 28.

しかして上記実施例において冷房負荷が大きい状態にお
いては、蒸発器９Ａの出口及び絞り前吸入管路１０Ａに
おいて予め設定された圧力（設定圧力）よりも高い圧力
が得られた状態にある事により、そして蒸発器９Ａの出
口及び絞り前吸入管路１０Ａは吸入圧力の導圧路２３を
介して吸入圧力室２１と連通状態にある事により、同吸
入圧力室２１内の圧力が大気圧力室２２内の圧力（大気
圧＋ばね２５の付勢圧）に打ち勝ってベローズ２０を収
縮させた状態にある。そしてこの様にベローズ２０が収
縮状態にある事によりボール弁２６はばね３１の付勢圧
を介して弁座３ｏに当接した状態、即ち、狭搾口２９を
閉塞する状態にある。However, in the above embodiment, when the cooling load is large, a pressure higher than the preset pressure (set pressure) is obtained at the outlet of the evaporator 9A and the pre-throttling suction pipe 10A, so that Since the outlet of the evaporator 9A and the pre-throttling suction pipe 10A are in communication with the suction pressure chamber 21 via the suction pressure guide path 23, the pressure in the suction pressure chamber 21 is reduced to the atmospheric pressure chamber 22. The bellows 20 is in a contracted state by overcoming the pressure (atmospheric pressure + biasing pressure of the spring 25). Since the bellows 20 is in the contracted state as described above, the ball valve 26 is in a state of contacting the valve seat 3o through the biasing pressure of the spring 31, that is, a state of closing the narrowing opening 29.

一方、吐出圧力室３３は絞り通路３８Ａを介して圧縮機
２の吐出室若しくは吐出管路５と連通状態にある事によ
り、同吐出圧力室３３に対して吐出圧力を送り込む作用
が得られる。そしてこの様に吐出圧力室３３に対して吐
出圧力が送り込まれる事により、同吐出圧力室３３内の
圧力がばね室３４内に介装するばね３６の付勢圧に打ち
勝ってスプール弁３５をばね室３４方向に後退させる状
態、即ち、吸入管路１０を大きく開く状態が得られる。On the other hand, the discharge pressure chamber 33 is in communication with the discharge chamber of the compressor 2 or the discharge conduit 5 via the throttle passage 38A, so that the effect of sending discharge pressure to the discharge pressure chamber 33 can be obtained. By feeding the discharge pressure into the discharge pressure chamber 33 in this manner, the pressure within the discharge pressure chamber 33 overcomes the biasing pressure of the spring 36 interposed in the spring chamber 34, causing the spool valve 35 to spring. A state in which the suction pipe 10 is moved back toward the chamber 34, that is, a state in which the suction pipe 10 is wide open, is obtained.

又、車室内の冷房負荷が減少して蒸発器９Ａの出口圧力
が設定圧力（大気圧子ばね２５の付勢圧）を下回った状
態において、大気圧力室２２内の圧力（＝設定圧力）が
吸入圧力室２１内の圧力に打ち勝ってベローズ２０を伸
長させる状態が得られると共に同ベローズ２０の伸長を
介してプッシャー２７がボール弁２６を押圧する状態、
即ち、ばね３１の付勢圧に打ち勝って狭搾口２９を開く
状態が得られ、此により吸入圧力室２１内の圧力（絞り
前吸入管路１０Ａ内の吸入圧力）を弁室２８、絞り通路
３８Ｂ、３８Ａの各部を経て吐出圧力室３３内に送り込
む作用（絞り通路３８Ａ、３８Ｂには吐出圧力が常時送
り込まれるのであるが、その量は極僅かであるため両絞
り通路３８Ａ、３８Ｂに対して吸入圧力を送り込む事が
出来る）が得られる。そしてこの様に吐出圧力室３３に
対して吸入圧力が送り込まれる事により、ばね室３４内
の圧力（ばね３６の付勢圧）が吐出圧力室３３内の圧力
（絞り前吸入圧力）に打ち勝ってスプール弁３５を絞り
前吸入管路１０Ａ方向に向けて押し出す作用、即ち、吸
入管路１０の開口面積が狭められて吸入ガスの流量を制
限する作用が得られ、此により蒸発器９Ａの出口圧力が
一定圧力（設定圧力）に保持される。In addition, when the cooling load in the vehicle compartment decreases and the outlet pressure of the evaporator 9A falls below the set pressure (biasing pressure of the atmospheric pressure spring 25), the pressure in the atmospheric pressure chamber 22 (= set pressure) a state in which the pressure in the suction pressure chamber 21 is overcome and the bellows 20 is extended, and the pusher 27 presses the ball valve 26 through the extension of the bellows 20;
That is, a state is obtained in which the narrow throttle opening 29 is opened by overcoming the biasing pressure of the spring 31, and as a result, the pressure in the suction pressure chamber 21 (the suction pressure in the pre-throttling suction pipe 10A) is transferred to the valve chamber 28 and the throttle passage. 38B, 38A into the discharge pressure chamber 33 (discharge pressure is always sent to the throttle passages 38A, 38B, but the amount is very small, so it is not necessary for both the throttle passages 38A, 38B suction pressure can be sent). By feeding the suction pressure into the discharge pressure chamber 33 in this way, the pressure in the spring chamber 34 (biasing pressure of the spring 36) overcomes the pressure in the discharge pressure chamber 33 (suction pressure before throttling). An effect of pushing the spool valve 35 toward the pre-throttling suction pipe 10A, that is, an effect of narrowing the opening area of the suction pipe 10 and restricting the flow rate of the suction gas, is obtained, thereby reducing the outlet pressure of the evaporator 9A. is maintained at a constant pressure (set pressure).

第５図と第６図に表わす第３の実施例において、吸入絞
り弁１１には絞り前吸入管路１０　Ａと対向させてボア
１２が穿設される。同ボア１２は第１の実施例と同様蒸
発器９Ａの出口側に開口部を存して有底円筒状に形成さ
れると共にボトム側に圧力室１３を存してスプール弁］
４が進退自在に嵌挿される。そして同スプール弁１４に
は連通路３７が穿設され、圧力室１３と絞り前吸入管路
１０Ａは相互に連通する如く設けられる。又、同スプー
ル弁１４のヘッド側の一端に形成するばね受は座１５と
、同ばね受は座１５と対面させてボア１２の開口部に形
成するばね受は座１６間にばね１７が介装され、同ばね
１７により上記スプール弁１４は常時はボトム側（圧力
室１３側）に向けて付勢された状態にある様に設けられ
る。In the third embodiment shown in FIGS. 5 and 6, a bore 12 is formed in the suction throttle valve 11 so as to face the pre-throttle suction pipe 10A. As in the first embodiment, the bore 12 is formed into a bottomed cylindrical shape with an opening on the outlet side of the evaporator 9A, and has a pressure chamber 13 on the bottom side as a spool valve]
4 is inserted and inserted so that it can move forward and backward. A communication passage 37 is bored in the spool valve 14, and the pressure chamber 13 and the pre-throttling suction pipe 10A are provided so as to communicate with each other. A spring holder formed at one end of the head side of the spool valve 14 has a seat 15, and a spring holder formed at the opening of the bore 12 facing the seat 15 has a spring 17 interposed between the seats 16. The spool valve 14 is normally biased toward the bottom side (pressure chamber 13 side) by the same spring 17.

一方、同吸入絞り弁１１のボトム側にはベローズ２０が
伸縮自在に設けられると共に同ベローズ２０を間に存し
て吸入圧力室２１と大気圧力室２２が対峙させて設けら
れる。そして吸入圧力室２１は吸入圧力の導圧路２３を
介して絞り前吸入管路１０Ａと連通ずる如く設けられる
一方、大気圧力室２２は通気口２４を介して大気と連通
ずる如く設けられると共にばね２５が介装され、両圧力
室２１．２２間に生ずる圧力差を介して上記ベローズ２
０を伸縮させる事が出来る様に設けられる。On the other hand, a bellows 20 is extendably provided on the bottom side of the suction throttle valve 11, and a suction pressure chamber 21 and an atmospheric pressure chamber 22 are provided facing each other with the bellows 20 in between. The suction pressure chamber 21 is provided so as to communicate with the pre-throttling suction pipe 10A via the suction pressure guide line 23, while the atmospheric pressure chamber 22 is provided so as to communicate with the atmosphere via the vent 24, and the spring 25 is interposed, and the bellows 2 is
It is provided so that 0 can be expanded or contracted.

又、ベローズ２０の先端部にはプッシャー２７が突設さ
れる一方、同プッシャー２７と対面させてボート３９と
弁室２８が形成され、同弁室２８にはボール弁２６が係
留される。更に具体的にはポー１フー ート３９と弁室２８は狭搾口２９を介して相互に連通ず
る如く設けられる。そして同弁室２８には狭搾口２９部
分に弁座３０が形成され、同弁座３０に対してボール弁
２６を当接させる事が出来る設けられる。又、同弁室２
８にはばね３１が介装され、同ばね３１を介して常時は
弁座３０を閉塞する方向に向けて付勢された状態にある
様に設置フられる。そして又、前記プッシャー２７の先
端部はベローズ２０の伸縮を介して弁室２８内に臨む事
が可能な如く設けられる。即ち、」１記ばね；３］の付
勢圧力に打ち勝ってボール弁２６を弁室２８内に押し戻
す事が可能如く設けられる。又、図ン１（省略しである
が吐出管路５より吐出圧力の導圧路４０が延設され、そ
の先端部は」１記弁室２８、狭搾口２９、ボート３９の
各部を経て前記圧力室１−３と連通ずる如く設けられる
。Further, a pusher 27 is protruded from the tip of the bellows 20, and a boat 39 and a valve chamber 28 are formed facing the pusher 27, and a ball valve 26 is moored to the valve chamber 28. More specifically, the port 1 foot 39 and the valve chamber 28 are provided so as to communicate with each other via the narrow opening 29. A valve seat 30 is formed in the valve chamber 28 at the narrowing opening 29, and the ball valve 26 can be brought into contact with the valve seat 30. Also, the same valve chamber 2
A spring 31 is interposed in the valve 8, and the valve seat 8 is installed so that it is normally biased in the direction of closing the valve seat 30 via the spring 31. Furthermore, the tip of the pusher 27 is provided so that it can face the inside of the valve chamber 28 through the expansion and contraction of the bellows 20. That is, the ball valve 26 is provided so as to be able to push the ball valve 26 back into the valve chamber 28 by overcoming the biasing pressure of the spring 1.3. In addition, a pressure guide line 40 for the discharge pressure is extended from the discharge pipe line 5, and the tip thereof passes through the valve chamber 28, the narrow opening 29, and the boat 39. It is provided so as to communicate with the pressure chamber 1-3.

しかして上記実施例において冷房負荷が大きい状態にお
いては、蒸発器９Ａの出口及び絞り前吸入管路１０Ａに
おいて予め設定された圧力（設定圧力）よりも高い圧力
が得られた状態にある事により、そして蒸発器９Ａの出
口及び絞り前吸入管路１０Ａは吸入圧力の導圧路２３を
介して吸入圧力室２１と連通状態にある事により、同吸
入圧力室２１内の圧力が大気圧力室２２内の圧力（＝設
定圧力）に打ち勝ってベローズ２０を収縮させた状態に
ある。そしてこの様にベローズ２０が収縮状態にある事
によりボール弁２６はばね３１の付勢圧を介して弁座３
０に当接した状態、即ち、狭搾口２９を閉塞する状態（
吐出圧力の導圧路４０を閉塞する状態）にある。そして
又、この様に狭搾口２９が閉塞された状態にある事によ
り、ボア１２においてスプール弁１４はばね１７の付勢
圧によって圧力室１３方向に向けて後退させる状態、即
ち、吸入管路１０を大きく開く状態が得られる。However, in the above embodiment, when the cooling load is large, a pressure higher than the preset pressure (set pressure) is obtained at the outlet of the evaporator 9A and the pre-throttling suction pipe 10A, so that Since the outlet of the evaporator 9A and the pre-throttling suction pipe 10A are in communication with the suction pressure chamber 21 via the suction pressure guide path 23, the pressure in the suction pressure chamber 21 is reduced to the atmospheric pressure chamber 22. The bellows 20 is in a contracted state by overcoming the pressure (=set pressure). Since the bellows 20 is in the contracted state in this way, the ball valve 26 is moved to the valve seat 3 through the biasing pressure of the spring 31.
0, that is, a state in which the narrow squeeze opening 29 is closed (
(a state in which the pressure guide path 40 for the discharge pressure is closed). Furthermore, since the narrowing opening 29 is in the closed state, the spool valve 14 in the bore 12 is in a state where it is retracted toward the pressure chamber 13 by the biasing pressure of the spring 17, that is, the suction pipe 10 is wide open.

又、車室内の冷房負荷が減少して蒸発器９Ａの出口圧力
が設定圧力を下回った状態において、大気圧力室２２内
の圧力が吸入圧力室２１内の圧力に打ち勝ってベローズ
２０を伸長させる状態が得られると共に同ベローズ２０
の伸長を介してプッシャー２７がボール弁２６を押圧す
る状態、即ち、ばね３１の付勢圧に打ち勝って狭搾口２
９を開く状態（吐出圧力の導圧路４０を開く状態）が得
られ、此により弁室２８、狭搾口２９、ボート３９の各
部を経て圧縮機２の吐出室若しくは吐出管路５内の吐出
圧力を圧力室１３内に送り込む作用が得られる。そして
この様に圧力室１３に対して吐出圧力が送り込まれる事
により、スプール弁１４がばね１７の付勢圧に打ち勝っ
てスプール弁１４を絞り前吸入管路１０Ａ方向に向けて
押し出す作用、即ち、吸入管路１０の開口面積が狭めら
れて吸入ガスの流量を制限する作用が得られ、此により
蒸発器９Ａの出口圧力が一定圧力（設定圧力）に保持さ
れる。In addition, when the cooling load in the vehicle compartment decreases and the outlet pressure of the evaporator 9A falls below the set pressure, the pressure in the atmospheric pressure chamber 22 overcomes the pressure in the suction pressure chamber 21, causing the bellows 20 to expand. is obtained and the same bellows 20
The state in which the pusher 27 presses the ball valve 26 through the extension of the
9 is opened (a state in which the pressure guide path 40 for the discharge pressure is opened), and as a result, the pressure in the discharge chamber of the compressor 2 or in the discharge pipe line 5 passes through each part of the valve chamber 28, the narrowing opening 29, and the boat 39. The effect of feeding the discharge pressure into the pressure chamber 13 can be obtained. By feeding the discharge pressure into the pressure chamber 13 in this way, the spool valve 14 overcomes the biasing pressure of the spring 17 and pushes the spool valve 14 toward the pre-throttling suction pipe 10A, that is, The opening area of the suction pipe 10 is narrowed to obtain the effect of restricting the flow rate of suction gas, thereby maintaining the outlet pressure of the evaporator 9A at a constant pressure (set pressure).

〔発明の効果〕〔Effect of the invention〕

本発明は以上の様に構成されるものであって、上記の様
に吸入絞り弁を蒸発器出口の設定圧力を基準として開閉
させる様にした事により、同蒸発器出口の圧力を常時一
定圧力（設定圧力）に保持する事が出来るに至った。そ
してこの様に蒸発器出口の圧力を常時一定圧力（設定圧
力）に保持する事が可能となった事により、蒸発器より
車室内に向けて吹き出される冷風の温度を略一定の温度
に保持する事が出来るに至り、此により車室内における
空調フィーリングを著しく向上させる事が出来るに至っ
た。The present invention is constructed as described above, and by opening and closing the suction throttle valve based on the set pressure at the outlet of the evaporator as described above, the pressure at the outlet of the evaporator is kept constant at all times. We were able to maintain the pressure at (set pressure). In this way, by making it possible to maintain the pressure at the evaporator outlet at a constant pressure (set pressure) at all times, the temperature of the cold air blown out from the evaporator into the passenger compartment is maintained at a nearly constant temperature. This has made it possible to significantly improve the feeling of air conditioning inside the vehicle.

そして又、本発明にあっては圧縮機の起動時において吸
入絞り弁を閉塞状態とする事が出来る事により、起動時
における立ち上がりショックを効果的に緩和させる事が
出来るに至った。Furthermore, according to the present invention, since the suction throttle valve can be closed when the compressor is started, it has become possible to effectively alleviate the start-up shock at the time of starting the compressor.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図と第２図は第１の実施例を表わす図面であって、
第１図は冷房負荷が大きい状態を表わす冷凍サイクルの
概略図、第２図は冷房負荷が小さい状態を表わす同冷凍
サイクルの概略図である。 第３図と第４図は第２の実施例を表わす図面であって、
第３図は冷房負荷が大きい状態を表わす冷凍サイクルの
概略図、第４図は冷房負荷が小さい状態を表わす同冷凍
サイクルの概略図である。第５図と第６図は第３の実施
例を表わす図面であって、第５図は冷房負荷が大きい状
態を表わす冷凍＝２１− サイクルの概略図、第６図は冷房負荷が小さい状態を表
わす同冷凍サイクルの概略図である。第７図は従来構造
を表わす図面であって、同じく冷凍サイクルの概略図で
ある。 １・・・エンジン、２・・・圧縮機、３・・・ベルト伝
導機構、４・・・電磁クラッチ、５・・・吐出管路、６
・・・凝縮機、７・・・冷媒液タンク（レシーバ）、８
・・・膨張弁、９・・・冷却ユニット、９Ａ・・・蒸発
器、９Ｂ・・・送風機、１０・・・吸入管路、ＩＯＡ・
・・絞り前吸入管路、ＩＯＢ・・・絞り後吸入管路、１
１・・・吸入絞り弁、１２・・・ボア、１３・・・圧力
室、１４・・・スプール弁、１５・・・ばね受は座、１
６・・・ばね受は座、１７・・・ばね、１８・・・導圧
路、１８Ａ・・・吸入圧力の導圧路、１８Ｂ・・・吐出
圧力の導圧路、１９Ａ、１９Ｂ・・・電磁弁、２０・・
・ベローズ、２１・・・吸入圧力室、２２・・・大気圧
力室、２３・・・吸入圧力の導圧路、２４・・・通気口
、２５・・・ばね、２６・・・ボール弁、２７・・・プ
ッシャー、２８・・・弁室、２９・・・狭搾口、３ｏ・
・・弁座、３１・・・ばね、３２・・・ボア、３３・・
・吐出圧力室、３４・・・ばね室、３５・・・スプール
弁、３６・・・ばね、３７・・・連通路。 ３８Ａ、３８Ｂ・・・絞り通路、３９・・・ボート４０
・・・吐出圧力の導圧路。FIG. 1 and FIG. 2 are drawings showing a first embodiment,
FIG. 1 is a schematic diagram of a refrigeration cycle showing a state where the cooling load is large, and FIG. 2 is a schematic diagram of the same refrigeration cycle showing a state where the cooling load is small. 3 and 4 are drawings showing the second embodiment,
FIG. 3 is a schematic diagram of the refrigeration cycle showing a state where the cooling load is large, and FIG. 4 is a schematic diagram of the same refrigeration cycle showing a state where the cooling load is small. Figures 5 and 6 are drawings showing the third embodiment, in which Figure 5 is a schematic diagram of a 21-cycle refrigeration cycle that shows a state where the cooling load is large, and Figure 6 shows a state where the cooling load is small. FIG. 2 is a schematic diagram of the refrigeration cycle shown in FIG. FIG. 7 is a diagram showing a conventional structure, and is also a schematic diagram of a refrigeration cycle. DESCRIPTION OF SYMBOLS 1... Engine, 2... Compressor, 3... Belt transmission mechanism, 4... Electromagnetic clutch, 5... Discharge pipe, 6
...Condenser, 7...Refrigerant liquid tank (receiver), 8
...Expansion valve, 9...Cooling unit, 9A...Evaporator, 9B...Blower, 10...Suction pipe, IOA・
... Suction pipe before throttling, IOB... Suction pipe after throttling, 1
1... Suction throttle valve, 12... Bore, 13... Pressure chamber, 14... Spool valve, 15... Spring bearing seat, 1
6... Spring bearing is seat, 17... Spring, 18... Pressure guiding path, 18A... Pressure guiding path for suction pressure, 18B... Pressure guiding path for discharge pressure, 19A, 19B...・Solenoid valve, 20...
・Bellows, 21... Suction pressure chamber, 22... Atmospheric pressure chamber, 23... Pressure guide path for suction pressure, 24... Ventilation port, 25... Spring, 26... Ball valve, 27... Pusher, 28... Valve chamber, 29... Narrow squeeze mouth, 3o.
...Valve seat, 31...Spring, 32...Bore, 33...
-Discharge pressure chamber, 34...spring chamber, 35...spool valve, 36...spring, 37...communication passage. 38A, 38B... Throttle passage, 39... Boat 40
...Pressure path for discharge pressure.

Claims (1)

【特許請求の範囲】[Claims] （１）　蒸発器と圧縮機とを繋ぐ吸入管路に介在させて
吸入絞り弁を進退自在に設け、蒸発器出口の圧力が設定
圧力を上回る状態においては上記吸入絞り弁を後退させ
て吸入管路を大きく開くと共に蒸発器出口の圧力が設定
圧力を下回る状態においては吸入絞り弁を前進させて吸
入管路を閉塞する様に設けて成る冷凍サイクルにおける
蒸発器出口圧力の制御機構。(1) A suction throttle valve is provided in the suction pipe connecting the evaporator and the compressor so that it can move forward and backward, and when the pressure at the evaporator outlet exceeds the set pressure, the suction throttle valve is moved back and the suction pipe is closed. A control mechanism for the evaporator outlet pressure in a refrigeration cycle, which is configured to widen the evaporator outlet and move a suction throttle valve forward to close the suction pipe when the pressure at the evaporator outlet is lower than a set pressure.