JPH04303196A - Variable displacement compressor - Google Patents

Abstract

PURPOSE:To obtain a variable displacement compressor which can control the compression capacity with high accuracy without any increase in size of the system and without requiring the dimensional accuracy not so high by providing a control means including an opening portion adapted to move in the substantially radial direction of the base of a cylinder to open and close an opening portion. CONSTITUTION:When a control valve 8 closes a by-path port 7, a pin 11 is pressed upward to a guide groove 12 of a control plate 10 by a guide spring 13. A closing portion of the control valve 8 forms a wedge-shaped taper portion 8A fitted to a taper groove 14 of a center plate 4, and the taper portion 8A is pressed to the taper groove 14 of the center plate 4 with the guide spring 13 by the rotation of the control plate 10. Accordingly, the control valve 8 is pressed to prevent incomplete closing also by the internal pressure applied from a compression space 20 in the condition of closing the by-path port 7, so as to enable desired correct control for closing and opening the by-path port 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement compressor, and more particularly, a cylinder rotor is eccentrically supported within a cylinder space, and one or more The present invention relates to a variable displacement compressor that forms a compression chamber, and particularly to improvements in its variable displacement mechanism.

0002

[Prior Art] In a compressor, pressure reducer, pump, supercharger, etc. of a vehicle air conditioning system, a cylinder rotor is arranged eccentrically in a cylinder space, and the cylinder rotor is eccentrically disposed in a cylinder space between the inner circumferential surface of the cylinder case of the housing and the outer circumferential surface of the rotor. 2. Description of the Related Art Compressors are known that compress a medium by forming a compression chamber.

[0003] Generally speaking, in a compressor used in a vehicle's air conditioning system, the rotor of the compressor is directly connected to the crankshaft of the engine, which undergoes extremely large changes in rotational speed, and fine adjustment of the discharge pressure is performed by adjusting the rotor's rotor. This cannot be done by controlling the rotation speed, etc.

However, in order to provide the necessary compression performance when the engine rotates at low speeds, and to prevent damage to the refrigerant pipes due to an excessive pressure rise or freezing due to a drop in the suction pressure of the evaporator when the engine rotates at high speeds, , it is necessary to suppress excessive compression in the compressor. The discharge pressure control of the compressor performed for this purpose is often performed through adjustment control of the compression capacity of the medium in the compression chamber, and compressors of this type with a variable capacity mechanism are called variable capacity compressors. It is called.

Referring to FIG. 6, Japanese Patent Application Laid-Open No. 62-261691
The conventional variable displacement compressor described in the publication will be explained. This figure shows the structure of this compressor as a sectional view taken in a direction orthogonal to the cylinder axis of the compressor. housing 30
defines a cylinder space 31, in which a cylindrical eccentric rotor 32 having a diameter smaller than that of the cylinder space 31 is disposed, and an outer circumferential surface 3 of the eccentric rotor 32 is disposed.
3 is adjacent to a portion of the inner circumferential surface 34 of the housing 30. Four vanes 35 are disposed on the eccentric rotor 32 so as to be freely retractable, and the eccentric rotor 32 rotates in the direction of the arrow while dividing the inside of the cylinder space 31 into four compression chambers by the vanes 35.

In the cylinder space 31, a suction hole (port) 36 serving as a medium inlet, a discharge hole 37 serving as a medium outlet, and a compression chamber are communicated with the suction side to release the medium to the suction side.
A plurality of (four in the figure) bypass holes 38 are provided to reduce the compression capacity of the compression chamber. The bypass hole 38 is
They are arranged at different distances from the discharge hole 37, and some or all of them can be closed. With this configuration, compression is not performed until the rotor passes through the open bypass hole, and the discharge pressure can be controlled by changing the compression capacity of the compressor by opening and closing the bypass hole 38.

The control piston 40 is actuated by the suction pressure of an evaporator (not shown) disposed on the suction side of the compressor, and is driven in a linear direction by, for example, pneumatic control or solenoid control. The opening or closing of the bypass holes 38 arranged at each position is controlled depending on the position of the control piston 40. For example, if the suction pressure of the evaporator is too low, the control piston 40 can be moved upward in the drawing. The bypass hole 38 on the side closer to the discharge hole 37 is opened. In response to this new opening of the bypass hole 38, the effective compression capacity of the compression chamber becomes smaller.

In addition to the above-mentioned types of variable displacement compressors, variable displacement compressors are also known which are similarly equipped with an eccentric rotor, but which revolve around the center of the cylinder space while preventing the rotor from rotating. In this case, instead of the vanes 35 that slide in grooves formed on the outer circumference of the rotor, a separator is used that blocks the rotation of the rotor and partitions the compression chambers. A variable capacity compressor having a revolving rotor has the advantage of having almost no sliding parts and extremely little wear.

[0009]

[Problems to be Solved by the Invention] In the variable capacity mechanism of the conventional variable capacity compressor, the medium is sent from the suction hole 36 according to the rotation of the rotor 32 in the direction of the arrow (or revolution in the case of an orbiting rotor). Inertia toward the discharge side is already given at the opening position of the bypass hole 38, and the direction of this inertia is perpendicular to the direction of the bypass hole, so the compressor operates at high speed and the inertia of the medium increases. When this happens, it is difficult for the medium to flow out effectively from the bypass hole 38, and there is a tendency that the desired amount of bypass cannot be obtained.

According to the configuration in which the amount of bypass is increased by increasing the area of the opening of the bypass hole, it is necessary to increase the diameter itself of the control piston 40 that closes the bypass hole. As a result, it is unavoidable that the compressor as a whole becomes larger, resulting in problems such as impairing the efficiency of the arrangement of the entire air conditioning equipment.

Furthermore, because of the structure in which the bypass holes are sequentially closed or opened by a control piston that moves in a linear direction, there is a problem that the shape and arrangement of the bypass holes are limited to the shape and movement direction of the control piston. Furthermore, in order to reliably close the bypass hole and accurately control the bypass amount of the medium, there is also the problem that high dimensional accuracy of the piston and piston groove is required when manufacturing the control piston section.

Separately from this, in the case of the variable capacity compressor equipped with the revolving rotor, after the outer peripheral surface of the revolving rotor passes through the open bypass hole closest to the discharge side, the effective Although compression is possible, there is no known example in which the shape of the opening in the cylinder space has been considered from the viewpoint of effectively opening and closing the opening of the bypass hole.

The present invention improves the variable capacity mechanism of a conventional variable capacity compressor, and improves the opening of the bypass hole without increasing the size of the variable capacity compressor body or the air conditioning system equipped with this compressor. By setting the shape, the medium can be effectively released from the bypass hole to the suction side even during high-speed operation of the compressor, and the bypass hole can be reliably opened or closed without requiring very high dimensional accuracy. A first object of the present invention is to provide a variable capacity compressor equipped with a variable capacity mechanism that allows highly accurate adjustment of compression capacity.

Furthermore, the present invention improves the variable displacement compressor having a revolving rotor so that the revolving rotor can effectively compress the medium according to the opening or closing of the bypass hole selected by the variable displacement mechanism, thereby improving the effectiveness of the variable displacement compressor. A second object of the present invention is to provide a variable capacity compressor having a revolving rotor with high accuracy in capacity control and effective control of discharge pressure.

[0015]

[Means for Accomplishing the Object] In order to achieve the first object, the variable displacement compressor of the present invention includes a housing that forms a cylinder space therein, a housing that is eccentrically supported within the cylinder space, and a housing that is eccentrically supported within the cylinder space, and an inner circumferential surface of the housing, a cylinder rotor forming one or more compression chambers, a suction hole that communicates between the suction space and the compression chamber, a discharge hole that communicates the discharge space and the compression chamber, and the cylinder. A variable displacement compressor comprising: a bypass hole having an opening in a cylindrical bottom portion of the space and communicating the compression chamber and the suction space; and a control means for controlling an effective bypass amount of the bypass hole, wherein the opening is The cylinder has an elongated shape that is longer in the circumferential direction than in the radial direction, and the control means includes an opening closing means that moves substantially in the radial direction of the cylindrical bottom surface to close or open the opening. It is something.

Furthermore, the second object of the present invention is that the cylinder rotor is driven to revolve around the central axis of the cylinder space, and the radially outer edge of the opening and the outer circumferential surface of the cylinder rotor are connected to each other. This is achieved by a variable capacity compressor characterized in that the cylinder rotors substantially overlap when viewed in the axial direction at one revolution position of the cylinder rotor.

[0017]

[Operation] The opening of the bypass hole has an elongated shape elongated in the circumferential direction, and the control means has an opening closing means that opens or closes the opening by moving approximately in the radial direction of the bottom surface of the cylinder. Because the part has an elongated shape that is long in the circumferential direction,
The medium given circumferential inertia by the rotor can more easily pass through the bypass port and escape to the suction side than other bypass hole shapes with the same area, and can also close the bypass hole. Alternatively, even if the amount of radial movement of the opening closing means to open is small, it is possible to control an opening with a large area, and the closing or opening of the opening can be quickly controlled.

[0018] Furthermore, in a variable capacity compressor equipped with a revolving rotor, the radially outer edge of the opening and a part of the outer circumferential surface of the revolving rotor are axially located at one revolution position of the revolving rotor. Due to the configuration having a radial inclination that overlaps, when the outer circumference of the revolving rotor passes through the opening of the bypass hole that is open, the outer circumferential surface of the rotor rapidly moves to the radially outer edge position of the opening of the bypass hole. Since this opening can be closed at any time, the compression operation of the rotor is effectively and efficiently performed under the control of the variable displacement control mechanism, and the effective discharge pressure is accurately controlled.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in more detail with reference to the drawings. 1 and 2 are cross-sectional views, respectively, in a direction perpendicular to the axis and in an axial direction of a variable capacity compressor having a revolving rotor according to an embodiment of the present invention. In FIG. 2, the cylinder case 9, the inner steel plate 15, the front steel plate 16, and the rear steel plate 17, which constitute the housing as a whole, partition two cylinder spaces 18, and between both cylinder spaces 18 there is a center plate. 4 is placed. A discharge space 20 is provided on the outside of the cylinder case 9 and the center plate 4 in the circumferential direction, and communicates with both cylinder spaces 18 via the discharge hole 6 and the discharge valve 19 attached thereto.
will be arranged.

Crankshaft 1 directly connected to the engine
are the front boss 21 and rear plate 22 of this compressor.
One cylinder rotor (eccentric rotor) 3 is supported in the cylinder space 18 via a bearing 2 at each eccentric portion 1A thereof so as to be relatively rotatable. Both rotors 3 revolve within each cylinder space 18 with a phase difference of 180 degrees. A control plate 10 is provided between each rotor 3 and the inner steel plate 15 to control the bypass amount of the medium.

In FIG. 1, the rotor 3 has its outer peripheral surface 3A.
A part of the cylinder is in contact with the inner circumferential surface 9A of the cylinder case 9 and can revolve clockwise in the figure. The separator 21 consists of a cylindrical portion 21A and a plate portion 21B.
is slightly rotatably supported by the case 9,
The plate part 21B is inserted into the circumferential groove 3B of the rotor 3 to prevent the rotor 3 from rotating, and also to prevent the cylinder space 1 from rotating.
8 is divided into compression chambers 18A and 18B.

The compression chamber 18B on the right side of the figure is in a state before the medium is sucked from the suction hole 5, and the compression chamber 18B on the left side of the figure
B has already finished sucking the medium through the suction hole 5 and is in the compression stroke (assuming the bypass port 7 is closed). The cylindrical bottom of the cylinder space 18 is provided with an opening for one bypass port 7 at a position close to the discharge hole 6 and at a position slightly distant from the discharge hole 6 in the circumferential direction.
The opening has the shape shown in the same figure, that is, an elongated shape that is longer in the circumferential direction than in the radial direction, and its radially inner and outer edges extend in the direction of rotor movement caused by the revolution of the rotor 3. It has a radial slope that decreases the distance from the center of the cylinder space.

FIG. 3 is a cross-sectional view in a direction perpendicular to the axis, which is different from FIG. 1 and shows the closing and opening of the bypass port. Figures (A), (B), and (C) show states in which the bypass port 7 is fully closed, partially opened, and fully opened, respectively. A control piston 24 that can slide within a piston groove 23 indicated by a broken line is controlled, for example, by the suction pressure of an evaporator at the front stage of this compressor, and a groove 24 formed in the middle thereof
Guide the pin 25 of the control plate 10 through A. For this reason, the rotational position of the control plate 10 is controlled by the movement of the control piston 24 in the longitudinal direction via the pin 25.

The control plate 10 has guide grooves 12 formed at its inner periphery at different distances from the center of the cylinder in the circumferential direction, and is further provided with a guide spring 13 at a position facing the guide grooves 12. . The guide groove 12 and the guide spring 13 hold the guide pin 11 of the control valve 8 that closes the bypass port 7 therebetween, and with this configuration, the control plate 10 converts its rotational movement into a linear movement. , each control valve 8 is guided in a direction substantially orthogonal to the longitudinal direction of the opening of the respective bypass port 7.

FIG. 3(A) similarly shows a state in which both bypass ports are closed according to the linear position of the control piston 24 and the corresponding rotational position of the control plate.
The figure (B) shows a state in which one side is open, and the figure (C) shows a state in which both sides are open. By making the opening of the bypass port 7 shorter in the radial direction and longer in the circumferential direction,
Closing and opening of the opening by the control valve 8 is carried out very quickly, so that spatial volume control of the compression chamber by the control valve is carried out quickly in response to a change in the control pressure from the evaporator, for example.

[0026] The bypass port must ensure the selection of compression or non-compression by the rotor by quickly closing or opening as described above. For example, if the opening control of the bypass port is not quick enough, excessive compression will cause problems due to overcooling of the refrigerant, and if the bypass port is not reliably closed, unnecessary compression will occur and the medium will escape into the suction space, resulting in energy loss. arise.

The edge of the opening of the bypass port 7 has the above-mentioned radial inclination, and in particular, the radially outer edge is such that when the revolving rotor passes through this opening, the outer peripheral surface of the revolving rotor is inclined. It has a shape and position that partially overlaps when viewed in the axial direction. With this configuration, when the revolving rotor passes through the opening of the bypass port that is open, the opening is quickly closed by the revolving rotor, and therefore, the side closest to the discharge valve that is opened by the control valve 8 The revolving rotor 3 can rapidly close the opening of the bypass port 7, and according to the spatial compression chamber capacity control by the control valve, the effective compression chamber capacity adjustment by the rotor is performed, and the desired amount of control is achieved. can easily obtain a discharge pressure of

FIG. 4 is a partial view showing how the opening of the bypass port of the control valve 8 is closed.
-IV arrow view. In the figure, the control valve is shown with the bypass port 7 closed, and the pin 11 is connected to the guide groove 1 of the control plate 10 by the guide spring 13.
It is pressed upward in the figure. The closing portion of the control valve has a wedge-shaped tapered portion 8A that fits into the tapered groove 14 of the center plate 4, and the tapered portion 8A is fitted into the tapered groove 14 of the center plate by the guide spring 13 as the control plate 10 rotates. Being forced. Therefore, when the bypass port 7 is closed, the control valve 8 is prevented from being pushed by the internal pressure applied from the compression chamber 20 and incompletely closed, and the desired closing and opening of the bypass port 7 is achieved. Accurate control becomes possible.

FIG. 5 shows the control piston 2 in each figure of FIG.
FIG. 4 is a block diagram illustrating the control method of FIG. The evaporator suction pressure is controlled by the control piston 2.
It is led to the suction pressure chamber 25 of No. 4, and also to the pressure chamber 27 on the left side of the bellows 26A of the pressure regulator 26 in the drawing. When the compressor performs excessive compression and the suction pressure of the evaporator falls below a predetermined value, the bellows 26 expands to the left in the figure, and as a result, the ball 28 moves to the left in the figure against the spring 44, causing the ball valve to open. is opened, the pressure in the pressure chamber 29 to which the discharge pressure is guided is reduced by the action of the orifice 41, and at the same time, the pressure in the control chamber 42 of the control piston 24 is reduced, so the control piston 24 follows the spring 43 and moves to the left in the figure. move in the direction.

When the control piston 24 moves as described above as the suction pressure decreases, the control plate 10 rotates as shown in FIGS. The ones closest to each other open sequentially, reducing the effective compression capacity of the compression chamber and preventing excessive compression. In addition to this, the control piston can be controlled by a solenoid, which is driven in a linear direction. In this embodiment, this linear movement is first converted into rotational movement of the control plate, and then this rotation is directional movement is converted into linear movement of the control valve via the guide groove.

Regarding the above configuration, when compared with a configuration in which the bypass hole is opened or closed directly by the control piston, firstly, dimensional accuracy between the piston and the piston groove in the piston part is not required, and secondly, the bypass hole is Even if the area of the opening of the bypass hole is increased, there is no need to increase the diameter of the control piston, and the compressor does not become large. Thirdly, the shape of the bypass hole is not limited by the shape of the control piston, so This has the advantage that an elongated shape can be adopted and, fourthly, the degree of freedom regarding the position of the control piston is significantly increased.

By arranging the position and shape of the opening of the bypass hole as described above, it is easy to bypass the medium during high-speed operation of the compressor, and the opening and closing of the bypass port can be reliably controlled by the control valve. , the opening closes rapidly when the rotor outer circumference passes the radially outer edge of this bypass port, so the opening has a large open area until just before the rotor closes the opening with the outer circumference. The media can be quickly released to the suction side without being compressed, and after reaching the position where the media is compressed, the opening can be quickly closed to ensure that the media is compressed and sent out from the discharge hole. , energy efficiency is not impaired by unnecessary compression, and responsiveness is good.

Note that the mechanism for operating the control valve is as follows:
The drive member is not limited to a drive member consisting of a control piston and a control plate, but any drive member that opens and closes the opening of the bypass hole by moving in the radial direction is sufficient, and it is not necessarily necessary to employ a control piston or the like.

[0034]

[Effects of the Invention] As explained above, in the present invention,
The opening of the bypass hole has an elongated shape that is longer in the circumferential direction than in the radial direction, and the opening is controlled by an opening closing means that moves approximately in the radial direction on the cylindrical bottom surface of the cylinder space. The medium given inertia in the circumferential direction, which is the longitudinal direction of the section, can escape to the suction side more easily than other bypass holes with the same area, and the bypass hole can be closed or opened. Even if the amount of radial movement of the opening closing means is small, a large amount of bypass can be controlled, the closing or opening of the opening can be controlled accurately and precisely, and the discharge pressure can be controlled with high precision. We were able to provide a variable capacity compressor.

[0035] Furthermore, in a variable capacity compressor equipped with a revolving rotor, the radially outer edge of the opening and a part of the outer circumferential surface of the revolving rotor are axially located at one revolution position of the revolving rotor. Due to the overlapping configuration, when the outer circumference of the revolving rotor passes through the open opening of the bypass hole, the outer circumferential surface of the rotor rapidly closes this opening at the radially outer edge position of the opening of the bypass hole. Because you can
It has been possible to provide a variable displacement compressor having a revolving rotor in which the compression operation of the rotor is effectively and efficiently performed according to the control by the variable displacement control mechanism, and the discharge pressure can be controlled with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a sectional view taken in a direction orthogonal to an axis, showing the structure of a variable displacement compressor according to an embodiment of the present invention.

FIG. 2 is an axial cross-sectional view of the variable displacement compressor of FIG. 1;

[Fig. 3] A cross-sectional view taken in a direction perpendicular to the axis of the compressor showing the closing and opening of the bypass port. Indicates the condition.

FIG. 4 shows the state of closing of the opening of the bypass port, and is a view taken along the line IV-IV in FIG. 3(A).

FIG. 5 is a block diagram illustrating control of the control piston.

FIG. 6 is a cross-sectional view in a direction orthogonal to the axis showing the structure of a conventional variable displacement compressor.

[Explanation of symbols]

1 Crankshaft 3 Cylinder rotor 5 Suction hole 6 Discharge hole 7 Bypass hole (bypass port) 8
Control valve 9 Cylinder case 10 Control plate 11 Guide piston 12 Guide groove 13 Guide spring 24 Control piston 20 Casing 25 Cylinder space

Claims (2)

[Claims] 1. A housing forming a cylinder space therein, a cylinder rotor eccentrically supported within the cylinder space and forming one or more compression chambers between an outer circumferential surface and an inner circumferential surface of the housing, and a suction chamber. a suction hole that communicates between the space and the compression chamber; a discharge hole that communicates between the discharge space and the compression chamber;
A variable displacement compressor comprising: a bypass hole having an opening in the cylindrical bottom surface of the cylinder space and communicating the compression chamber and the suction space; and a control means for controlling an effective bypass amount of the bypass hole. The cylinder has an elongated shape that is longer in the circumferential direction than in the radial direction, and the control means includes an opening closing means that moves substantially in the radial direction of the cylindrical bottom surface to close or open the opening. Variable capacity compressor. 2. The cylinder rotor is driven to revolve around a central axis of the cylinder space, and a radially outer edge of the opening and a part of the outer circumferential surface of the cylinder rotor The variable displacement compressor according to claim 1, wherein the variable displacement compressors substantially overlap each other when viewed in the axial direction at one revolution position.