JPH01232178A - Variable displacement swash plate type compressor - Google Patents

Abstract

PURPOSE:To avoid getting any eccentric load due to thrust force by making a contact position between a pin and tilting groove almost accord with an axis of a shaft in a large capacity state in a compressor. CONSTITUTION:A tilting groove 166 is being installed in a flat plate part 165 of a shaft 1, and a pin through hole is formed in a swash plate 10. The flat plate part 165 of the shaft 1 is arranged in a slit 105 of the swash plate 10 and then engaged with the pin through hole and the tilting groove 166 of the shaft 1 by a pin 80 and a retaining ring. A contact point between the pin 80 and the tilting groove 166 should be made into a relationship so as to be situated on an axis of the shaft 1 when discharge capacity of a compressor comes to its large capacity. With this constitution, any occurrence of moment attributable to thrust force is thus preventable at the time of compressor large capacity.

Description

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

[Problem to be solved by the invention]

The present inventors previously developed a variable capacity swash plate compressor in which the swash plate, which is rotationally driven by a shaft, decreases its inclination angle in accordance with the axial movement of the spool, thereby making the stroke of the piston variable. We proposed a structure that would That is, the swash plate is attached to the shaft so as to be tiltable and displaceable in the axial direction of the shaft, and the inclination angle and center position of the swash plate are moved in conjunction with each other.

In such a variable capacity swash plate compressor, although there is a significant increase in dead volume in one working chamber as the swash plate inclination angle changes, there is no significant increase in dead volume in the other working chamber. , the capacity can be gradually reduced.

FIG. 2 is a sectional view showing a variable capacity swash plate compressor previously proposed by the present inventors. In this example, the swash plate 10 changes its inclination angle in accordance with the displacement of the spool 30. Furthermore, since the swash plate 10 is tiltably connected to the spherical support portion 405 of the spool, the angle of inclination of the swash plate 10 can be varied in accordance with the displacement of the spool 30. Therefore, in this compressor, by controlling the pressure within the control pressure chamber 200, the position of the spool 30 is displaced, and thereby the discharge capacity of the compressor can be continuously and variably controlled.

However, when the inventors conducted an experimental study on the compressor shown in FIG. 2, it was found that problems such as flaking occurred in the thrust bearing 15 installed in the front cylinder block 5. Therefore, the present inventors further considered the stress relationship occurring in the thrust bearing 15. To this thrust ring 15
This restricts the shaft 1 from being biased toward the front side. The shaft 1 receives a compression reaction force generated on the piston 7 via the pin 80, the swash plate 10, and the shoes 18 and 19. Therefore, the thrust force generated on the shaft 1 is maximum when the compression reaction force applied to the piston 7 is maximum. This occurs when the angle of inclination (anti-10) is at its maximum and the piston 7 reciprocates within the working chamber 50° 60 at its maximum stroke.

Therefore, the present inventors further investigated the stress state in the state where this thrust load is maximum.

As a result, as shown in FIG. 3, at the maximum capacity of the compressor, the connection point A between the pin 80 and the inclined groove 166 is
It has been found that this is caused by a predetermined amount of displacement from the central axis l. That is, in the compressor previously proposed by the present inventors, in order to minimize the installation area of the inclined groove 166, the inclined groove 166 is located approximately in the center of the shaft 1.
It was set to intersect with the axis l of. In other words,
In the inclined groove shape shown in FIG. 3, when the inclined angle of the swash plate 10 is at an intermediate position, the contact point A of the pin 80 is located at
It was designed to be displaced on axis 2 of .

Therefore, when the discharge capacity of the compressor is displaced to an intermediate capacity, the direction of the thrust force received via the pin 80 will deviate from the axis l of the shaft 1, but if the discharge capacity of the compressor is large capacity. When this occurs, the direction of the thrust force received via the pin 80 will be away from the axis l of the shaft 1.

Here, the thrust force becomes particularly problematic when the discharge capacity of the compressor is large as described above.

In a state where the direction of the thrust force deviates from the axis l of the shaft 1, not only the thrust force but also a moment due to the deviation is applied to the thrust bearing 15. A large load was applied to the thrust bearing 15 due to the combination of this moment and the thrust force, and it was recognized that this load was the cause of the above-mentioned flaking.

The present invention was devised in view of the above points, and aims to better support the thrust direction load in the variable capacity swash plate compressor that the present inventors had previously proposed. purpose.

[Structure and Operation] In order to achieve the above object, in the compressor of the present invention, the engagement relationship between the inclined groove and the pin is specified so as to be in a special state. That is, the contact point between the pin and the inclined groove is such that the shaft is on the axis when the discharge capacity of the compressor becomes large.

By establishing such a relationship, even when the discharge capacity of the compressor is large and the thrust force applied to the shaft is large, the direction of the thrust force can be made to coincide with the shaft axis.

Therefore, according to the compressor of the present invention, the generation of moment due to thrust force can be prevented when the compressor has a large capacity. As a result, the thrust load applied to the thrust bearing can be effectively prevented from becoming excessive.

〔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. Aluminum alloy front housing 4° front side plate 8. Suction valve9. Front cylinder block 5. Rear cylinder block 6° intake valve 12. The rear side plate 11 and the rear housing 13 form an outer shell of the compressor that is integrally fixed by through bolts 16. As shown in FIG. 4, the cylinder bronc 5.6 is provided with five cylinders 64 (641 to 645) each arranged parallel to each other.

A shaft 1, which rotates under the driving force of an automobile engine (not shown), is rotatably supported by a front housing 4 and a rear housing 13, respectively, via a bearing 3 and a hair ring 14. Further, the thrust force applied to the shaft 1 (the force acting in the left direction in the figure) is received by the front cylinder block 5 via the thrust bearing 15, thereby restricting the movement of the shaft 1 in the right direction in the figure.

The thrust force acting on the slide portion 40 (the force acting in the right direction in the figure) is received by the spool 30 via the thrust bearing 116,
The annular locking portion 17 prevents the slide portion 40 from coming off the spool 30.

Note that this locking portion 17 is formed on the outer surface of the thrust portion 4o. The spool 30 is disposed within the cylindrical portion 65 of the rear cylinder block 6 and the cylindrical portion 135 of the rear housing 13 so as to be slidable in the axial direction.

Further, a slit 105 is formed on the side surface of the shaft 1 of the swash plate 10, and a flat plate portion 165 is formed on the end surface of the shaft 1 on the 1° side of the swash plate. 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 transferred to the swash plate 10.
It is something that can be conveyed to people.

Furthermore, shoes 18 and 19 are slidably disposed on both sides of the swash plate 10. On the other hand, a piston 7 is slidably disposed within the cylinder 64 of the front cylinder block 5 and the cylinder 63 of the rear cylinder block 6. As described above, the shoes 18 and 19 are slidably attached to the swash plate 10. Furthermore, the shoes 18 and 19 are rotatably engaged with the inner surface of the piston 7. Therefore, the rocking motion accompanying the rotation of the swash plate lO is transmitted to the piston via the shoes 18 and 19 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.

The flat plate portion 165 of the shaft 1 is provided with an inclined groove 166 as shown in FIG. 5, and the swash plate 10 is provided with a pin hole. Flat plate portion 165 of shaft 1
After being placed in the slit 105 of the swash plate 10, the pin 80 and the retaining ring are used to connect the pin through hole and the inclined groove 166 of the shaft 1.
It is locked with. In addition, in this example, the pin 80 is a pin core material 80.
1 and a cylindrical sliding member 802 fitted on its surface.

The inclination of the swash plate changes depending on the position of the pin 80 within this inclined groove 166, and as the inclination changes, the position of the center of the swash plate also changes. That is, the second working chamber 6 on the right side in FIG.
0, even if the inclination of the swash plate 10 changes and the stroke of the piston 7 changes, the top dead center of the working chamber 60 of the piston 7 hardly changes, and the slope is such that the dead volume does not substantially increase. A groove 166 is provided. On the other hand, in the working chamber 50 on the left side in the figure, the tilt of the swash plate changes and the top dead center of the piston 7 changes, so the de-rad volume also changes.

In this example, as described above, the inclined groove 166 is formed in such a shape that the top dead center position of the working chamber 60 of the piston 7 does not change even if the inclination angle of the swash plate IO changes. Therefore, strictly speaking, the inclined groove 166 has a curved shape, but in actual formation, it can be approximated by a substantially straight long groove.

In the compressor previously proposed by the present inventors, the inclined grooves 1 and 66 intersect with the axis i of the shaft 1 approximately at the center thereof, as explained in FIG. 3 above. However, in the compressor of this example, the inclined groove 166 is
The shaft 1 is formed so as to be located on the axis β of the shaft 1 in a state where the displacement is changed to the maximum displacement side of the compressor. As a result, the inclined groove 166 is entirely displaced downward, as is clear from the comparison between FIGS. 3 and 5. As a result, in the compressor of this example, the volume of the flat plate portion 165 increases as a whole.

However, in the compressor of this example, the direction of the thrust force F coincides with the shaft 1 and the axis l when the thrust force F is at its maximum discharge capacity. As a result, the thrust force F is evenly distributed and supported by the thrust bearing 15. In particular, since no moment is generated due to the thrust force F, the overall load applied to the thrust ring 15 can be reduced.

Reference numeral 21 in the figure is a shaft sealing device, which prevents refrigerant gas and lubricating oil from leaking to the outside through 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 500 in the figure is a control valve for controlling the internal pressure of the control pressure space 200, and one side of the control valve 500 is connected to the suction pressure space 69 at the rear end of the shaft l by a low pressure introduction passage 97. The other end is connected to the control pressure chamber 200 via a control pressure passage 98 and communicates with the discharge chamber 93 via a high pressure introduction passage 96 and a throttle 99.

A discharge space 90 on the front side in FIG. 1 is led to a discharge port by a discharge passage (not shown) formed in the cylinder block 5, and a discharge space 93 on the rear side is led to a discharge port by a discharge passage formed in the cylinder block 6. being led to the port. Since both discharge ports are connected by external piping, the internal pressures of the discharge space 90 and the discharge space 93 are the same pressure. In addition, the intake space 72 on the front side is led to the intake space 70 formed in the center of the housing by the intake passage 71.
Similarly, the rear suction space 74 is also guided to the suction space 70 by the 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.

Since no pressure difference occurs inside the compressor at startup, no pressure difference occurs before and after the spool 30 in this state. That is, at the time of startup, the slide portion 4
No load is applied in the direction of tilting the swash plate 10 through 0.

When the shaft 1 starts rotating in this state, the rotation of the shaft 1 causes the piston 7 to reciprocate via the swash plate IO. As the piston 7 moves back and forth, 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 7 and the shoes 18, 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 7 acts as a moment in the direction of decreasing the inclination angle of the swash plate 10.

For example, when the transmission pin 80 is located on the axis X in FIG. 4, the piston disposed in the first cylinder space 641 does not generate a moment that changes the inclination angle with respect to the swash plate 10. However, a rotational moment is generated from the pistons 7 disposed in the second to fifth cylinder spaces 642, 643, 644, and 645 in a direction that reduces the inclination angle of the swash plate 10. This rotational moment will be received by the moment generated around the pin 80. Further, the rotational moment generated by the piston 7 applies a pressing force to the spherical support portion 405.

In other words, when there is no differential pressure across the spool 30,
The slide portion 40 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, since the swash plate 10 is regulated by the transmission pin 80 in the inclined groove 166 of the shaft 1, the swash plate 10 reduces the inclination and applies force to the center of the swash plate 10 in the left direction in the figure. Move the center position of the plate 10 to the right. The force acting on the slide portion 40 in the right direction in the figure is transmitted to the spool 30 via the thrust bearing 116, and the spool 30 moves until it hits the bottom of the rear housing 13. This state is the state in which the discharge capacity of the compressor is at its minimum.

The refrigerant gas sucked through the suction port 710 (connected to the evaporator of the refrigeration cycle) enters the suction space 70 in the center, then passes through the suction passage 73 and enters the suction chamber 74 on the rear side. Thereafter, during the suction stroke of the piston 7, the air is sucked into the working chamber 60 from the suction port 25 via the suction valve 12. The sucked refrigerant gas is compressed in the compression stroke,
Once compressed to a predetermined pressure, the discharge valve 22 is pushed through the discharge port 24 and the discharge chamber 93 is discharged. 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 compression ratio is smaller than that of the second working chamber 60 on the rear side, and the pressure of the refrigerant gas in the first working chamber 50 is lower than that in the discharge space 90. The pressure is lower than the pressure (from which the discharge pressure of the second working chamber 60 on the rear side is led), and the action of sucking and discharging refrigerant gas in the first working chamber 50 on the front side is not performed.

When the compressor is started, the compression stage discharge capacity becomes the minimum capacity as described above. However, in this state where the suction pressure is equal to the discharge pressure, the absolute pressure of the refrigerant pressure in the suction pressure chamber 74 is also higher than the set pressure. Therefore, the pressure introduced into the pressure chamber 501 by the low pressure introduction passage 97 is higher than the set pressure of the control valve 500, and as a result, the control valve 500 communicates the high pressure introduction passage 96 and the control pressure passage 98.

Similarly, it is known that even after the compressor is activated, the pressure inside the suction chamber 74 of the compressor increases when the capacity required by the refrigeration cycle is high. This is due to superheating in the evaporator of the refrigeration cycle, and if the pressure of the refrigerant sucked into the compressor increases in this way, the control pressure chamber 200 will flow through the high pressure introduction passage 96 as in the case of startup described above. It is electrically connected to the discharge chamber 93. Therefore, the high pressure within the discharge chamber 93 is gradually introduced into the control pressure chamber 200 via the throttle 99. As a result, the pressure within the control pressure chamber 200 gradually increases.

Therefore, a force acting on the spool 30 in the left direction in FIG. 1 (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 slide portion 40 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 inclined groove 166 of the shaft 1 and the transmission pin 80, the swash plate lO moves its center of rotation to the left in the figure and increases its inclination. Furthermore, a control pressure chamber 200
As the internal pressure increases, the spool 30
5) moves to the left in the figure until it hits 11 (rear side play) to achieve the maximum capacity state. In this state, refrigerant gas sucked through the suction port 710 enters the central suction space 70, passes through the suction passages 71 and 73, and flows into the suction chambers 72 and 74, respectively. In the suction stroke, the air 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 7, and flows from the discharge port 24 through the discharge valve 22 into the discharge space. 90 and 93, passes through a discharge passage, is discharged from a discharge port, and joins at an external pipe. In this state, both the working chambers 50 and 60 perform the action of sucking in and discharging refrigerant gas.

Thereafter, when the compressor discharge capacity required from the refrigeration cycle decreases, the pressure of the refrigerant sucked into the compressor decreases accordingly. This is due to a decrease in superheat in the evaporator of the refrigeration cycle, an increase in the amount of throttling of the expansion valve of the refrigeration cycle, etc.

In this state, the signal pressure passage 98 and the low pressure introduction passage 97 are electrically connected. As a result, the pressure within the control pressure chamber 200 is released to the suction pressure space 69 side. As a result, the pressure difference occurring before and after the spool 30 is reduced, and the spool is displaced to the right in FIG. 1 due to the same pressure state as described at the time of startup described above.

That is, in the compressor of this example, the spool 30 is continuously displaced in accordance with the pressure of the refrigerant sucked into the compressor, and thereby the discharge capacity of the compressor is also continuously changed.

In this way, in the compressor of this example, the discharge capacity of the compressor can be continuously varied and controlled from the minimum customer base to the maximum capacity according to the control of the control valve 500. Moreover, in the compressor of this example, since the position of the inclined groove 166 is displaced downward in the figure, thrust force is applied on the axis of the shaft l at maximum capacity. As a result, eccentric load is effectively prevented from being applied to the shaft 1 when the thrust force is at its maximum. Therefore, in the compressor of this example, the support balance of the thrust load F becomes appropriate, and the vibration resistance and durability of the compressor can be improved.

In the compressor of the present invention, the thrust load is supported by the thrust hair rings 15 and 116, but at the same time, the thrust load is transmitted to the shaft 1 via the pin 80. Like the thrust hair rings 15 and 116, they are made of a hard and wear-resistant metal material. In this example, it is made of carbon steel whose surface hardness has been increased by heat treatment such as carburizing.

〔Effect of the invention〕

As explained above, in the compressor of the present invention, the eccentric load caused by the thrust force is well avoided even when the thrust force generated inside the compressor is large, so the durability of the compressor is greatly improved. It has the excellent effect of improving

[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 sectional view showing a compressor '4'r6 previously proposed by the present inventors, and Fig. 3 is a sectional view showing an embodiment of the compressor of the present invention. FIG. 4 is a sectional view showing the cylinder block of the compressor shown in FIG. 1, and FIG. 5 is a front view showing the inclined groove shape of the compressor shown in FIG. 1. 1...shaft, 7...piston, 10...&H
H, 30... Spool, 40... Slide part, 80
···pin. 105...Slit part, 165...Flat plate part, 166
...Slanted groove. Representative Patent Attorney Takashi Okabe (Figure 3 1e+) Figure 5

Claims (1)

[Claims] (1) A cylinder block having a cylinder chamber inside; a shaft rotatably supported within the cylinder block and having a flat plate portion in a part thereof; and a slit into which the flat plate portion of the shaft is fitted;
a swash plate that is swingably connected to the shaft through engagement between the slit and the flat plate portion and rotates integrally with the shaft; and a swash plate that is slidably disposed within the cylinder chamber and that controls the swing movement of the swash plate. a piston that reciprocates within the cylinder chamber in response to the piston; a working chamber that is formed at each end of the piston between the inner surface of the cylinder chamber and that sucks, compresses, and discharges fluid; A support part that swingably supports the swash plate, and a spool that displaces the support part in the axial direction of the shaft, and the flat plate part has an inclined groove formed in each of the slit parts. A pin through hole is formed, and the swash plate is swingably connected to the shaft by the pin inserted into the pin through hole and the inclined groove, and the contact position between the pin and the inclined groove is determined. . A variable capacity swash plate compressor, characterized in that the compressor is substantially aligned with the axis of the shaft when the compressor is in a large capacity state.