JPH01219362A - Compressor - Google Patents

Abstract

PURPOSE:To abate the weight of a piston as a whole as well as to reduce vibration and noise in a compressor so sharply by forming a sealing part in a piston end, and making a part other than this sealing part diametrally smaller. CONSTITUTION:Reaction force being added to a swash plate 10 is decomposed into a radial component and an axial component with a piston 1000. A sealing part 1001 formed in an end of the piston 1000 is large in its diameter as compared with a central part of the piston 1000 and opposed to an inner surface of a cylinder 64 via a minute clearance. Seal length l1' at the side of a shaft 1, out of the sealing part 1001 is made larger. Consequently, in the sealing part 1001, load being added to load points A, B is abatable, so that any increase in sliding resistance of the piston 1000 is preventable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a compressor, and is effective when used as a refrigerant compressor for an automobile air conditioner, for example.

[Conventional technology and problems]

In a conventional compressor, a piston 100 as shown in FIG.
0 was used. This piston 1000 is disposed within a cylinder chamber of a swash plate compressor, and a seal portion 1001 is formed at its end to prevent refrigerant from leaking out within the working chamber.

On the other hand, in recent years, compressors have been required to further reduce vibration and noise in order to improve the driving feeling. Since the piston reciprocates within the cylinder chamber of the compressor, it is recognized that the inertial force of the piston has a large effect on the noise and vibration of the compressor. Therefore,
In order to reduce the vibration and noise of the compressor, it is desirable to reduce the weight of the piston and reduce the piston inertia.

Therefore, as shown in FIG. 3, the present inventors reduced the seal length a of the seal portion 1001 at the tip of the piston 1000 in order to reduce the weight of the entire piston. The seal length a is required to prevent the refrigerant in the compressor working chamber from leaking from the side of the piston 1000, and making the seal length a too small will affect the efficiency of the compressor. Undesirable. Therefore, the present inventors minimized the seal length a within a range that did not impair the performance of the compressor.

However, it has been found that when a piston 1000 with a minimum seal length is used as shown in FIG. 3, the power required to drive the compressor increases and the durability of the piston is also inferior.

In particular, according to the studies of the present inventors, the piston center side of the piston 1001 and the inner side of the compressor (the third
It was found that there was a large amount of wear at the piston end side of the seal portion 1001 (section B in the figure) and at the outer side of the compressor (section A in FIG. 3).

The inventors further investigated this point and found that it is due to the pressure balance applied to the piston 1000. FIG. 4 shows the pressure balance on piston 1000. This piston 1000 receives the rocking motion of the swash plate 10 via shoes 18 and 19. In FIG. 4, Fp indicates a reaction force exerted on the piston 1000 by the compressed refrigerant in the compression chamber. The reaction force R of the swash plate 10 opposing this reaction force FP is
The axial component force Rs of 0 and the radial component force Rr of the swash plate 10
It is decomposed into. Then, the axial component force Rs is the reaction force Fp
Since it is located on the same axis as , it cancels out. On the other hand, the radial component force Rr is the load Fa applied to the seal portion 1001 of the piston 1000.

' It will be supported by the cylinder block by Fb. Since the radial component force Rr is generated at the connection point between the swash plate 10 and the piston 1000, that is, at the shoe 18, the reaction forces Fa and Fb directly opposing this component force Rr are generated at the seal portion 1001 of the piston 1000. This occurs especially at the ends.

Here, since the radial component force Rr applied to the swash plate lO and the reaction forces Fa and Fb of the piston are balanced, the values of the reaction forces Fa and Fb are as follows. 1. In other words, it is recognized that it becomes a reaction force.

Therefore, as shown in FIG. 3, it is recognized that the seal portion becomes large and the reaction forces Fa and Fb become large.

[Problem to be solved by the invention]

The present invention is based on the above-mentioned research results of the present inventors, and reduces the inertia force of the entire piston, thereby reducing the vibration of the compressor.
Reduces compressor driving force while reducing noise, and
The purpose is to improve the wear resistance of the piston.

[Configuration and operation]

In order to achieve the above object, the present invention reduces the number of piston seals to reduce the inertia of the entire piston.

Further, in the piston of the present invention, the reaction force generated in the piston seal portion is reduced by making the seal length of the seal portion different between the piston on the center side of the compressor and the side on the outside of the compressor.

That is, in the piston according to the present invention, the seal portion is longer at the center side of the compressor and shorter at the outer side of the compressor. As a result, the reaction force generated at the piston seal portion can be reduced, and the power required to drive the compressor can be reduced. Furthermore, the increase in wear on the piston caused by the above-described low reaction force is effectively prevented.

(Example〕 An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a longitudinal sectional view of a variable displacement swash plate compressor. The aluminum alloy front housing 4, front side plate 8, suction valve 9, front cylinder block 5, rear cylinder block 6, suction valve 12, rear side plate 11, and rear housing 13 are integrally fixed by through bolts (not shown). It forms the outer shell of the compressor.

The cylinder blocks 5 and 6 each have five cylinders 64 (641 to 645) as shown in FIG.
4 are formed parallel to each other. A shaft 1 that rotates under the driving force of an automobile engine (not shown) is rotatably supported by a front housing 4 and a front cylinder block 5 via bearings 2 and 3, respectively. Further, the thrust force (force exerted in the left direction in the figure) applied to the shaft 1 is received by the front cylinder block 5 via the thrust bearing 15, and the movement of the shaft 1 in the right direction in the figure is restricted by a retaining ring. Note that the retaining ring is retained by an annular groove formed in the shaft 1.

The rear shaft 40 connects to the spool 3 via the bearing 14.
0 and is rotatably supported. The thrust force acting on the rear shaft 40 (the force acting in the right direction in the figure is generated by the thrust bearing 1
The rear shaft 40 is received by the spool 30 via the rear shaft 16, and a retaining ring prevents the rear shaft 40 from coming off the spool 30.

This retaining ring is also locked in an annular groove formed in the rear shaft 40. Spool 30 is rear cylinder block 6
and the cylindrical portion 135 of the rear housing 13 so as to be slidable in the axial direction.

A spherical part 107 is formed in the center of the swash plate 10, and a spherical support part 405 fixed to the Oti part of the rear shaft 40 is disposed on this spherical part 107. It is supported by a support section 405.

A slit 105 is formed on the side surface of the shaft 1 of the swash plate 10, and a flat plate portion 16 is formed on the end surface of the shaft 1 on the swash plate 10 side.
5 is formed. By disposing the flat plate portion 165 in surface contact with the inner wall of the slit 105, the rotational driving force applied to the shaft 1 is transmitted to the swash plate 10.

Furthermore, shoes 18 and 19 are slidably disposed on both sides of the swash plate 10. On the other hand, a piston 1000 is slidably disposed within the cylinder 64 of the front cylinder block 5 and the cylinder 64 of the rear cylinder block 6. As mentioned above, the shoes 18 and 19 are connected to the swash plate 10.
It is slidably attached to the Also shoe 1
8 and 19 are rotatably engaged with the inner surface of the piston 1000. Therefore, the rocking motion accompanying the rotation of the swash plate 10 is transmitted to the piston 1000 through the shoes 18 and 19.
is transmitted as a reciprocating motion. The shoes 18 and 19 are formed so that their outer surfaces lie on the same spherical surface when assembled on the swash plate 10.

A long groove 166 is provided in the flat plate portion 165 of the shaft 1, and a pin hole is formed in the swash plate 10. After the flat plate portion 165 of the shaft 1 is arranged in the slit 105 of the swash plate 10, it is locked in the pin passage hole and the long groove 166 of the shaft 1 by the pin 80 and the retaining ring. The inclination of the swash plate changes depending on the position of the pin 80 in this long groove 166, and as the inclination changes, the center of the swash plate (the spherical part
The position of the spherical support portion 405) of No. 7 also changes. That is, in the second working chamber 60 on the right side in FIG. 1, even if the inclination of the swash plate 10 changes and the stroke of the piston 1000 changes, the top dead center of the piston 1000 on the working chamber 60 side hardly changes and remains dead. The long grooves 166 are provided so that substantially no increase in volume occurs. On the other hand, in the working chamber 50 to the left in the figure, the tilt of the swash plate changes and the piston 100
Since the top dead center of 0 changes, the dead volume also changes.

In this example, as described above, the long groove 166 is formed in such a shape that even if the inclination angle of the swash plate 10 changes, the top dead center position of the piston 1000 on the working chamber 60 side does not change. Therefore, strictly speaking, the long groove 166 has a curved shape, but in actual formation, it can be approximated by a substantially straight long groove. Furthermore, in this example, the flat plate portion 165 is formed by forming the long groove 166.
The long groove 166 is arranged on the axis of the shaft l so that the shape of the shaft l does not become excessively large. Like this long groove 1
66 on the axis of the shaft 1 to reduce the size of the flat plate portion 165 is particularly effective in a swash plate type compressor in which the flat plate portion 165 is disposed inside the piston 7.

Reference numeral 21 in the figure is a shaft sealing device, which prevents refrigerant gas and lubricating oil from leaking to the outside along the shaft 1. Reference numeral 24 in the figure opens into the working chamber 50.60, and the discharge chamber 90.60.
The discharge port 24 is opened and closed by the discharge valve 22 . The discharge valve 22 has a valve holder 23
It is also fixed to the front side plate 8 and the rear side plate 11 by bolts (not shown). In the drawing, reference numeral 25 denotes a suction port that communicates the working chamber 50.60 and the suction chamber 72.74, and is opened and closed by the suction valve 9 and the suction valve 12.

Reference numeral 400 in the figure is a control valve for controlling the internal pressure of the control pressure space 200, and is controlled by a control circuit 500.

One end of the control valve 400 is connected to the rear suction space 74 by a low pressure introduction passage 97. The other end is connected to the discharge space 93 via the throttle 99 and the high pressure introduction passage 96, and is also connected to the control pressure chamber 200 via the control pressure passage 98.

When the electromagnetic valve 400 is not energized, the space 200 and the discharge space 93 are connected through the aperture 99 .

A discharge space 90 on the front side in FIG. 1 is led to a discharge port by a discharge passage formed in the cylinder block 5.
Further, the rear side discharge space 93 is led to a discharge port by a discharge passage formed in the cylinder block 6. Since the re-discharge boat is connected by external piping, the discharge space 9
0 and the pressure inside the discharge space 93 are the same pressure. The front suction space 72 is led to the suction space 70 formed in the center of the housing by a suction passage 71, and the rear suction space 74 is similarly led to the suction space 70 by a suction passage 73.

The operation of the compressor with the above configuration will be described.

When an electromagnetic clutch (not shown) is connected and driving force from the engine is transmitted to the shaft 1, the compressor is started.

When the compressor drive signal is input to the controller 500,
The controller 500 outputs an electric signal to the control valve to connect the low pressure introduction passage 97 and the signal pressure passage 98. Therefore, at startup, the pressure inside the suction chamber 74 is introduced into the control pressure chamber 200. Therefore, in this state, no pressure difference occurs before and after the spool 30.

That is, at the time of startup, no load is applied in the direction of tilting the swash plate 10 via the support portion 107.

When the shaft 1 starts rotating in this state, the rotation of the shaft 1 causes the piston 1000 to reciprocate via the swash plate 10. As the piston 1000 reciprocates, the refrigerant is sucked, compressed, and discharged within the working chamber 50, 60.

However, in this case, a force based on the pressure difference between the rear working chamber 60 and the front working chamber 50 is applied to the swash plate 10 via the piston 1000 and the shears 18 and 19. In particular, since the swash plate 10 is swingably supported by the spherical support part 405 and receives the rotational force of the shaft 1 by fitting the slit 105 and the flat plate part 165, the force applied to the piston 1000 acts as a moment in the direction of decreasing the inclination angle of the swash plate 10.

For example, when the pin 80 is located on the axis X in FIG. 5, the piston disposed in the first cylinder space 641 does not generate a moment that changes the tilt angle with respect to the swash plate 10. However, a rotational moment is generated from the pistons 1000 disposed in the second to fifth cylinder spaces 642, 643, 644, 645 in a direction that reduces the inclination angle of the swash plate 10. This rotational moment is
It will be received by the moment generated around the pin 80. Further, the rotational moment generated by the piston 1000 applies a pressing force to the spherical support portion 405.

That is, when the control valve introduces suction pressure into the control pressure chamber 200, the spherical support portion 405 and the spool 30 are displaced to the right in the figure. As a result, the swash plate 10 reduces its angle of inclination. However, the swash plate 10 is connected to the long groove 166 of the shaft 1.
Since the swash plate 10 is regulated by the pin 80, the inclination of the swash plate 10 is reduced and the ball portion 405 at the center of the swash plate 10 is regulated by the pin 80.
The rear shaft 40 is applied to the rear shaft 40 via the spherical support part 405, which applies force to the right in the figure and moves the spherical part 405 to the right.
The force acting in the right direction in the figure is transmitted to the spool 30 via the thrust bearing 16, and the spool 30 is connected to the rear housing 1.
Move until you hit the bottom of 3. In this state, the discharge capacity of the compressor is at its minimum.

The refrigerant gas sucked from a suction boat (not shown) (connected to the evaporator of the refrigeration cycle) enters the central suction space 70, then passes through suction passages 71 and 73.
Enter the front and rear suction chambers 72 and 74. after that,
During the suction stroke of the piston 1000, air is sucked into the working chamber 50, 60 from the suction port 25 via the suction valve 12.

The sucked refrigerant gas is compressed in a compression stroke, and when compressed to a predetermined pressure, the discharge valve 22 is pushed open through the discharge port 24 and discharged into the discharge chamber 90.93. The high-pressure refrigerant gas passes through the discharge passage and is discharged from the discharge port to a condenser (not shown) of the refrigeration cycle.

At this time, since the first working chamber 50 on the front side has a large dead volume, the pressure of the refrigerant gas in the first working chamber 50 is reduced by the pressure inside the discharge space 90 (the discharge pressure in the second working chamber 60 on the rear side is derived). ), and the suction and discharge of refrigerant gas in the front-side first working chamber 50 is not performed.

When starting the compressor, the compressor discharge capacity is set to the minimum capacity as described above. However, when the compressor capacity required by the refrigeration cycle is high, the control valve 400 shuts off the control pressure passage 98 and the low pressure introduction passage 97. Here, in this example, the control pressure chamber 200 communicates with a high pressure introduction passage 96 via a throttle 99. Therefore, in the state where the connection with the low pressure introduction passage 97 is cut off, the control pressure chamber 2
00, the influence of the discharge pressure received from the high pressure introduction passage 96 becomes large. Therefore, the pressure within the control pressure chamber 200 increases.

Therefore, the force acting on the spool 30 in the left direction in FIG. 1 due to the pressure difference (due to the pressure difference between the control pressure chamber 200 and the suction space 74) gradually increases as the compressor rotates. When this force overcomes the force pushing the spherical support portion 405 to the right in the figure, the spool 30 gradually begins to move to the left in the figure. Then, due to the action of the long groove 166 of the shaft 1 and the pin 80, the swash plate 10 increases its inclination while moving its center of rotation (spherical support portion 405) to the left in the figure. As the pressure inside the control pressure chamber 200 further increases, the spool 30 moves to the left in the figure until its shoulder 305 hits the rear side plate 11, achieving the maximum capacity state. This is the state shown in FIG. In the state shown in Fig. 1, refrigerant gas sucked from a suction port (not shown) enters the central suction space 70, passes through suction passages 71 and 73, and flows into suction chambers 72 and 74, respectively.
In the suction stroke, it enters the working chambers 50 and 60 from the suction port 25 through the suction valves 9 and 12, respectively, and is then compressed with the displacement of the piston 1000, and flows from the discharge port 24 through the discharge valve 22 into the discharge spaces 90 and 60, respectively. Enter 93,
It passes through a discharge passage, is discharged from a discharge boat, and joins with external piping. In this state, both the working chamber 50 and the working chamber 60 perform the action of sucking in and discharging refrigerant gas.

In this way, in the compressor of this example, the inclination angle of the swash plate 10 is variably controlled by the force applied to the spool 30 and the reaction force R of the piston 1000 received via the swash plate 10.

As shown in FIG.
is decomposed into an axial component force Rs. Therefore, the piston 1000 of this example has a seal portion 100 as shown in FIG.
1 is formed at the end of the piston. The seal portion has a larger diameter than the center of the piston 1000, and can face the inner surface of the cylinder 64 with a small gap therebetween. In other words, the piston of this example has the seal portion 100
Except for 1, the other parts have a small diameter, and the piston is 1000 mm.
This allows for a significant reduction in overall weight. The sealing portion 1001 is configured such that its sealing length llo is longer at the surface of one example of the shaft of the piston 1000.

In this example, the seal length on the shaft 1 side is 2. ” is 1
It is about 5am. On the other hand, the seal length on the opposite side! ,” is shorter.

In this example, this seal length! ,” is 1OIII1
It is about 1. Note that the seal length 21'' at this minimum portion is the minimum and sufficient length necessary for the seal portion 10010 to function.

In this example, as described above, the seal length of the surface of the seal portion 1001 on the shaft l side! , ゛ are increased, the load Fa applied to the load points A and B of the seal portion 1001
, Fb can be reduced. Therefore, an increase in the sliding resistance of the piston 1000 can be prevented, and the power required to drive the piston can be small.

In the above example, a variable displacement type compressor in which the angle of inclination of the swash plate 10 changes is shown as a compressor, but the piston of this example can also be used in a compressor in which the angle of inclination of the swash plate 10 is fixed. This is effective.

〔Effect of the invention〕

As explained above, in the compressor of the present invention, the weight of the entire piston is reduced by forming a seal portion at the end of the piston and making the portion other than the seal portion small in diameter. This has the excellent effect of reducing the inertial force of the piston and significantly reducing the vibration and noise of the compressor.

Moreover, in the piston of the present invention, the seal length of the seal portion is different between the compressor center side and the outer side of the piston, so even though the weight of the piston is reduced as described above, Therefore, the reaction force applied to the piston does not increase.

As a result, the sliding resistance of the piston can be suppressed to a small value, and the power required to drive the piston can be reduced, which is an excellent effect.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the compressor of the present invention, Fig. 2 is a front view showing a piston used in a conventional compressor, and Fig. 3 is a front view showing a piston studied by the present inventors. Figure 4 is an explanatory diagram showing the pressure applied to the piston shown in Figure 3,
FIG. 5 is a sectional view of the compressor shown in FIG. 1 taken along the line ■-V, and FIG. 6 is a front view showing a piston used in the compressor shown in FIG. 1. 1...Shaft, 10...Swash plate, 18.19...
Shoe, 1000... Piston, 1001... Seal portion. Representative Patent Attorney Takashi Okabe Figure 2/ Figure 3 Figure 5

Claims (2)

[Claims] (1) a cylinder block having a cylinder chamber therein; a shaft rotatably supported within the cylinder block; a swash plate that rotates integrally with the shaft; a swash plate slidably disposed within the cylinder chamber; a piston that reciprocates within the cylinder chamber in response to the rocking motion of the swash plate; the piston has a seal portion at its end that directly faces the cylinder chamber through a small gap; A compressor characterized in that the seal length on the shaft side is longer than the seal length on the opposite side from the shaft. (2) A piston that is slidably disposed in a cylinder chamber of a compressor, the end of the piston bulging out compared to the center side of the piston, and sliding directly with the cylinder chamber through a small clearance. A moving seal surface is formed, and the seal length of this seal surface is such that the seal length of the piston on the inside of the compressor is longer than the seal length of the piston on the outside of the compressor. A piston for a compressor characterized by: