JP2002070779A - Screw-type fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preferable screw-type fluid machine, such as a screw compressor used in a refrigerator or an air-conditioner or a pump, whereby a volumetric control of a compression chamber, which is divided with a sliding valve or the like, can be realized suitably by a simple structure and to succeed the cost reduction. SOLUTION: The screw type fluid machine is constituted so as to control a solenoid valve for selectively changing pressure supplied to a drive piston to slide and shift a slide valve to any one of high pressure and low pressure in refrigerant gas pressure or the like by a PWM controller. A simple and inexpensive volumetric control mechanism is obtained to reduce the number of the solenoid valves, piping connected to a control passage and the like by optionally controlling the volume of the screw compressor by turning on and off the solenoid valves by the PWM control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor, such as a screw compressor used in a refrigerating device or an air conditioner, which is compressed by a pair of male and female screw rotors and a slide valve disposed at a meshing portion of the rotor. The present invention relates to a screw-type fluid machine such as a screw compressor or a pump which divides a chamber and controls the capacity thereof.

[0002]

2. Description of the Related Art A screw compressor will be described as an example of a conventional screw type fluid machine with reference to FIGS. 4 is a longitudinal sectional view of a conventional screw compressor, FIG. 5 is a sectional view taken along line CC of FIG. 4, FIG. 6 and FIG.
FIG. 4 is an operation explanatory view of a capacity control mechanism.

As shown in FIGS. 4 and 5, reference numeral 11 denotes a male rotor,
Reference numeral 12 denotes a female rotor arranged in parallel with the male rotor in the same plane, and 1 denotes a meshing portion of a pair of male and female rotors 11, 12, which is slidably provided in the axial direction of the rotors 11, 12. A valve 2 is a driving piston of the slide valve 1, 3 is a piston chamber that applies a driving force to the driving piston 2, and 13 is a rotor case that houses the male rotor 11, the female rotor 12, and the like.

In the basic form of the screw compressor, a compression chamber 14 defined by a meshing portion between a male rotor 11 and a female rotor 12 and a rotor case 13 changes in volume as the male rotor 11 and the female rotor 12 rotate. It is configured to perform a compression action.

[0005] That is, the refrigerant gas is sucked from the suction port 21 and enters the suction chamber 23, and then is compressed by the rotation of the male rotor 11 and the female rotor 12 by the compression chamber 14 formed by the male rotor 11, the female rotor 12, and the rotor case 13. The high-pressure refrigerant gas is discharged to a discharge chamber 24 through a discharge port (not shown), and discharged from the discharge port 22 to the outside of the compressor.

Here, the male rotor 11, the female rotor 1
The compressed refrigerant gas sucked into the compression chamber 14 formed by the rotor case 13 and the compression chamber 14 maximizes the volume of the compression chamber 14 when the slide valve 1 is on the left side in the figure as shown in FIG. At the left end of the slide valve 1
Is compressed as it is, and is discharged from the discharge port to the discharge chamber 24, which is in the form of full load.

On the other hand, when the slide valve 1 is moving rightward in the figure as shown in FIG. 7, the volume of the compression chamber 14 is reduced by the movement of the left end of the slide valve 1 and the left end of the slide valve 1 is moved. Until the position, the compressed refrigerant gas is released to the suction side and returned, and compression is started from a position defined by the left end of the slide valve 1, and this is a form at the time of unloading.

As described above, the volume of the compression chamber 14 is arbitrarily controlled by the moving position of the slide valve 1 which slides in the axial direction of the male rotor 11 and the female rotor 12, whereby the capacity of the compressor is variable from the maximum capacity to the minimum capacity. Is controlled.

The sliding position of the slide valve 1 is controlled by controlling the pressure in a piston chamber 3 applied to a driving piston 2 directly connected to the slide valve 1.

That is, a control pressure passage 9 is connected to the piston chamber 3, and the control pressure passage 9 is connected to a high pressure side control pressure passage 7 connected to a high pressure side such as a compressor lubrication system hydraulic pressure or a refrigerant gas pressure. And a control pressure passage 8a provided with an electromagnetic valve 4 via a capillary 4a for pressure adjustment and a control pressure passage 8b provided with an electromagnetic valve 5 and connected to a low pressure side such as the refrigerant gas pressure. The side control pressure passage 10 communicates with the side control pressure passage 10 via the solenoid valve 6.

Accordingly, when the compressor is fully loaded, the solenoid valves 4 and 5 are closed and the solenoid valve 6 is opened, so that the front surface of the driving piston 2 is opened to the low-pressure side, and the rear surface of the driving piston 2 is closed. Is a communication hole 3a installed in the piston chamber 3.
Although the low pressure of the compressor acts to balance the pressure, the high pressure is applied to the end face 1a of the slide valve 1, and accordingly, the slide valve 1 moves to the left as shown in FIG.

On the other hand, when the capacity of the compressor is reduced, the solenoid valves 5 and 6 are closed and the solenoid valve 4 is opened, so that a capillary 4a is provided on the front side of the driving piston 2 through a control pressure passage 8a.
Therefore, the driving piston 2 moves rightward as shown in FIG. 7 due to the pressure difference between the front surface and the back surface of the driving piston 2, and the slide valve 1 correspondingly moves. Move to the right.

By closing the solenoid valve 4,
The slide valve 1 is held at an arbitrary position, and when stopped, the drive piston 2 is pressed to the right by a spring 30 incorporated in the front side of the drive piston 2.

At the time of reducing the capacity of the compressor,
If the opening and closing of the solenoid valves 4 and 5 are reversed from the above description, that is, the solenoid valves 4 and 6 are closed and the solenoid valve 5 is opened, the high pressure is controlled without being regulated by the capillary 4a. Since it acts directly on the driving piston 2 via the passage 8b, it is possible to cope with switching of rapid movement.

[0015]

However, in the above-mentioned conventional apparatus, a plurality of solenoid valves 4, 5, and 6, and a plurality of solenoid valves 4, 5, and 6, in order to arbitrarily control the capacity of the compressor depending on the position of the slide valve 1. , Capillary 4 for adjusting high pressure
a, and it is necessary to equip these with connecting pipes constituting the control pressure passage 8a and the control pressure passage 8b.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a suitable screw type fluid machine which solves such problems of the conventional apparatus, operates properly with a simpler structure, and achieves cost reduction. It is.

[0017]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problem. A slide valve slidable in the axial direction of a pair of male and female screw-shaped rotors is provided at a meshing portion of the male and female screw-shaped rotors. In a screw-type fluid machine for partitioning a compression chamber and slidingly moving the slide valve with a driving piston to control the capacity of the compression chamber, the slide valve is supplied to the driving piston that slides and moves. An object of the present invention is to provide a screw-type fluid machine provided with an electromagnetic valve for selectively switching pressure to either a high pressure or a low pressure in a refrigerant gas pressure or the like and a PWM control device for performing switching control of the electromagnetic valve. .

That is, according to the present invention, a PWM control device is provided with a solenoid valve for selectively switching a pressure supplied to a driving piston for slidingly moving a slide valve to a high pressure or a low pressure in a refrigerant gas pressure or the like. And the screw type fluid machine is configured to control the screw compressor volume by controlling the solenoid valve ON / OFF by PWM control. The number of solenoid valves, control pressure passage A simple and inexpensive capacity control mechanism is obtained by reducing the number of pipes and the like that are connected to the power supply.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory diagram of an operation of a capacity control mechanism corresponding to a main part of the screw type fluid machine according to the present embodiment at the time of full load, FIG. 2 is an operational explanatory diagram of an unloading operation, and FIG. 3 is related to the present embodiment. It is a control diagram of the solenoid valve for capacity control.

The construction and functions of the male rotor, the female rotor, the slide valve, and the like forming the compression chamber in the present embodiment are common to those of the above-mentioned conventional apparatus. Therefore, these common parts will not be described redundantly. The description of the conventional device will be referred to, and redundant description will be omitted as much as possible.

That is, in this embodiment, 101
Is a slide valve for capacity control, and the slide valve 1
Reference numeral 01 denotes a meshing portion between the male rotor 111 of the compressor and a female rotor (not shown), which is provided slidably in the axial direction of the male rotor 111.

102 is a piston for driving the slide valve 101, 130 is an adjusting spring for the piston 102,
103 is a piston chamber for holding the back pressure of the piston 102.

The piston 102 is governed by an operating force on the left side in the drawing due to the pressure in the piston chamber 103 applied to the back surface thereof and an operating force on the right side by the adjusting spring 130 in the drawing. To move left or right.

Reference numeral 123 denotes a control pressure passage.
One end of the solenoid valve 3 is connected to the piston chamber 103, and the other end has a solenoid valve 12 for capacity control having a connection port in three directions.
0 is connected.

Of the remaining two connection ports of the solenoid valve 120,
A control pressure passage 121 communicating with the high pressure side of the compressor lubrication system hydraulic pressure or refrigerant gas pressure is connected to one connection port,
The other connection port is connected to a control pressure passage 122 that communicates with a low pressure side such as the refrigerant gas pressure.

As shown in FIG. 3, the capacity control solenoid valve 120 is operated by receiving an external signal such as a cold water temperature of a refrigerator equipped with a screw compressor or an air temperature of an air conditioner. Holding time of OFF (the solenoid valve 120 is connected to the control pressure passage 122 communicating with the low pressure side) or ON (the solenoid valve 120 is connected to the control pressure passage 121 communicating with the high pressure side) by a capacity control calculating means (not shown) PWM (Pulse-width Modulati)
on) control is performed.

In this embodiment constructed as described above, upon receiving an external signal such as a chilled water temperature of a refrigerator equipped with a screw compressor or a blown air temperature of an air conditioner, a capacity control calculating means (not shown) is provided. Is a solenoid valve 120 for capacity control.
In response to this, a PWM control value for setting the output of the screw compressor corresponding to the external signal is output, and the PWM control for arbitrarily controlling the ON / OFF holding time of the solenoid valve 120 as shown in FIG. I do.

Here, when the solenoid valve 120 is OFF, the solenoid valve 120 is connected to the control pressure passage 12 communicating with the low pressure side.
2, a low pressure is applied to the piston chamber 103, so that the piston 102 moves rightward as shown in FIG. 2, and the slide valve 101 associated therewith moves rightward, and the screw compressor Maintain the unloaded state.

On the other hand, when the solenoid valve 120 is ON, the solenoid valve 120 is connected to the control pressure passage 121 communicating with the high pressure side.
, The piston 102 moves to the left as shown in FIG. 1 against the spring force of the adjusting spilling 130, and the slide valve 101 associated therewith is moved to the left. To maintain the full load state of the screw compressor.

The full load state shown in FIG. 1 and the unload state shown in FIG. 2 are set at both ends, and at this intermediate position, ON / OFF of the capacity control solenoid valve 120 is PWM-controlled in accordance with a predetermined setting, whereby the screw compression The capacity of the machine is arbitrarily controlled.

As described above, according to the present embodiment, the piston lubrication system 103 for supplying pressure to the piston 102 for driving the slide valve 101 is provided with the high pressure of the compressor lubrication system hydraulic pressure or the refrigerant gas pressure via the control pressure passage 121. Side,
A capacity control solenoid valve 120 communicating with the low pressure side via the control pressure passage 122 is connected by a control pressure passage 123, and the ON / OFF of the solenoid valve 120 is PWM-controlled to control the capacity of the screw compressor. The number of solenoid valves can be reduced as compared with the conventional system, and the number of piping connected to each control pressure passage is also reduced, making it simple and inexpensive. A capacity control mechanism can be provided.

Although the present invention has been described with reference to the illustrated embodiments, the present invention is not limited to such embodiments.
It goes without saying that various changes may be made to the specific structure within the scope of the present invention.

For example, in the above embodiment, one end of the control pressure passage 123 is connected to the piston 10 of the piston chamber 103.
2, the control pressure passage 12
The connection position of 3 is not limited to this position. In short, if the connection position is in harmony with the adjustment spring 130 and the slide valve 101 is slidably moved to the left and right, the connection position is opened at the front side of the piston 102. Is also good.

In the above embodiment, the control pressure of the piston 102 supplied to the piston chamber 103 is described by switching the solenoid valve 120 which is a so-called three-way valve. Solenoid valves are individually provided in the control pressure passage 122 on the low pressure side, and
By performing N / OFF PWM control, the same control as in the present embodiment can be performed.

Further, since the control pressure passages 121 and 122 are connected to the piston chamber 103 via the control pressure passage 123, the control pressure passage 123 is eliminated and the control pressure passages 12 and 122 are omitted.
1 and 122 are connected in parallel to the piston chamber 103 directly, solenoid valves are individually provided in the control pressure passages 121 and 122, and ON / OFF of each is controlled by PWM, thereby achieving the same control as in the present embodiment. Is possible.

[0036]

As described above, according to the present invention, a compression valve is partitioned by providing a slide valve slidable in the axial direction of a pair of male and female screw-shaped rotors at the meshing portion.
In a screw-type fluid machine that slides and moves the slide valve with a driving piston to control the capacity of the compression chamber, the pressure supplied to the driving piston that slides and moves the slide valve is determined by the refrigerant gas pressure or the like. A solenoid valve for selectively switching between high pressure and low pressure is provided, and a PWM control device for controlling the switching of the solenoid valve is provided to constitute a screw-type fluid machine. The screw type fluid machine is configured such that the electromagnetic valve for selectively switching the pressure supplied to the driving piston performing the sliding movement to either high pressure or low pressure in the refrigerant gas pressure or the like is controlled by the PWM control device. Thus, the capacity of the screw compressor can be arbitrarily controlled by turning on / off the solenoid valve by PWM control, and the number of solenoid valves, By reducing the piping that connects to your pressure passage, a simple one in which it was possible to obtain a suitable screw type fluid machine having an inexpensive displacement control mechanism.

[Brief description of the drawings]

FIG. 1 is an operation explanatory diagram at the time of full load of a capacity control mechanism corresponding to a main part of a screw type fluid machine according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view at the time of unloading of the capacity control mechanism shown in comparison with the time of full load in FIG. 1;

FIG. 3 is a control diagram of a solenoid valve for capacity control according to the present embodiment.

FIG. 4 is a longitudinal sectional view of a conventional screw compressor.

FIG. 5 is a sectional view taken along line CC of FIG. 4;

FIG. 6 is an operation explanatory diagram of a capacity control mechanism in the screw compressor of FIG. 4;

FIG. 7 is another operation explanatory view of the capacity control mechanism in the screw compressor of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slide valve 1a End surface 2 Drive piston 3 Piston chamber 3a Communication hole 4 Solenoid valve 4a Capillary 5 Solenoid valve 6 Solenoid valve 7 High pressure side control pressure passage 8a Control pressure passage 8b Control pressure passage 9 Control pressure passage 10 Low pressure side control pressure passage Reference Signs List 11 male rotor 12 female rotor 13 rotor case 14 compression chamber 21 suction port 22 discharge port 23 suction chamber 24 discharge chamber 30 spring 101 slide valve 102 piston 103 piston chamber 111 male rotor 120 solenoid valve 121 control pressure passage 122 control pressure passage 123 control pressure passage 130 Adjusting spring

Continued on the front page (72) Inventor Kazuya Shibata 2-1-1, Shinhama, Arai-machi, Takasago-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Takasago Machinery Works (72) Inventor Sou Sato 1-1, Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya-shi Mitsubishi Heavy Industries Nagoya Laboratory Co., Ltd. F-term (reference) 3H029 AA03 AB03 BB52 CC13 CC66

Claims (1)

[Claims] 1. A compression valve is provided at a meshing portion between a pair of male and female screw-shaped rotors, the slide valve being slidable in the axial direction of the rotor, and a compression chamber is defined, and the slide valve is slidably moved by a driving piston. In the screw-type fluid machine that performs volume control of the compression chamber, the pressure supplied to the driving piston that slides the slide valve,
A screw-type fluid machine comprising: an electromagnetic valve for selectively switching between high pressure and low pressure in a refrigerant gas pressure and the like; and a PWM control device for controlling switching of the electromagnetic valve.