JPH036348B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a variable capacity swash plate compressor in which the inclination angle of a swash plate that is rotationally driven together with a rotating shaft is variable, and in particular, the present invention relates to a variable displacement swash plate compressor in which the inclination angle of a swash plate that is rotationally driven together with a rotating shaft is variable. This invention relates to a variable capacity swash plate compressor in which refrigerant can more easily pass through a swash plate chamber housing a swash plate as the refrigerant is changed in a direction to decrease the swash plate.

"Prior Art and Problems" A type of swash plate compressor has an inflow passage and an outflow passage that lead to different parts of the refrigerant suction passage in the swash plate chamber, and utilizes the pressure difference that occurs when the refrigerant flows to unify the refrigerant. Some refrigerants pass through the swash plate chamber to lubricate and cool the inside of the swash plate chamber with lubricating oil mixed in the refrigerant. However, in a variable displacement swash plate compressor in which the piston stroke and refrigerant discharge capacity are changed by changing the inclination angle of the swash plate, the piston stroke is made small and the piston stroke is made small, so that the piston stroke is made small and the piston stroke is made small. First, during low-load operation when the discharge capacity of refrigerant is small, the amount of refrigerant flowing into the swash plate chamber becomes smaller than the amount of rotation of the swash plate, resulting in insufficient lubrication of the swash plate. In order to increase the amount of refrigerant passing through the swash plate chamber even during low-load operation, it is conceivable to form the inflow passage and outflow passage large. This increases the proportion of refrigerant that is absorbed, which leads to overheating of the refrigerant sucked in, especially during high-load operation with a large piston stroke, resulting in the disadvantage that the volumetric efficiency (discharge capacity) of the swash plate compressor decreases.

"Means for Solving the Problems" The present invention was made against the background of the above circumstances, and its purpose is to reduce the proportion of refrigerant passing through the swash plate chamber when the stroke of the piston is small. The purpose of the present invention is to provide a variable capacity swash plate compressor that is becoming larger in size.

In order to achieve such an object, the gist of the present invention is to provide a swash plate that is attached to a rotating shaft with a variable inclination angle, a swash plate chamber that accommodates the swash plate, and a swash plate chamber that accommodates the swash plate, and a A housing in which a plurality of cylinder bores having a center on a circumference are formed, and a piston that is fitted into each of the cylinder bores and sucks and discharges refrigerant by reciprocating in a stroke corresponding to the inclination angle of the swash plate. and an adjusting member that is connected to the swash plate so as to be rotatable relative to the swash plate and is provided in the housing, and that changes the inclination angle of the swash plate by moving relative to the housing; In a variable displacement swash plate compressor of the type in which a portion of the refrigerant drawn in through an inlet passage and an outlet passage provided is passed through the swash plate chamber, the outlet passage is provided with a stroke of the piston of the adjusting member. A valve is provided that opens as the piston moves in the direction of decreasing the piston, and the smaller the stroke of the piston, the greater the proportion of refrigerant passing through the swash plate chamber.

"Operation and Effects of the Invention" By doing this, the proportion of refrigerant passing through the swash plate chamber is increased during low-load operation when the stroke of the piston is small, which reduces the volumetric efficiency during high-load operation. This allows the swash plate to maintain good lubrication during low-load operation. Furthermore, during low load operation, the volumetric efficiency of the swash plate compressor decreases as the proportion of refrigerant passing through the swash plate chamber increases, but this is not a problem during low load operation as the amount of refrigerant discharged is not required. It is.

"Embodiment" Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

1 to 3, a pair of cylinder blocks 10F and 1 having mutually symmetrical shapes are shown.
In 0R, five cylinder bores 12F and 12R having centers on one circumference are formed at equal angular intervals, and both ends of five double-headed pistons 14 are slidably fitted into the cylinder bores 12F and 12R, respectively. ing. Each piston 14 is connected to the outer circumferential portion of a disc-shaped swash plate 18 via a pair of shoes 20 in a recess 16 formed on the inner circumferential side of the intermediate portion thereof. That is, the recess 16 is formed with a spherical recess 22 that faces each other with the swash plate 18 in between, and has a partial spherical surface 24 that engages with the recess 22 and a sliding surface 26 that slides into contact with the swash plate 18. death,
A pair of partially spherical shoes 20 whose spherical centers coincide with each other are inserted between the swash plate 18 and the piston 14. Therefore, even if the inclination angle of the swash plate 18 is changed, the pair of shoes 20 oscillate in a mutual relationship just like a single ball.
Combined distance (thickness) between shoe 20 and swash plate 18
does not change at all, and there are no gaps or twists in the connection between the piston 14 and the swash plate 18.
Therefore, the connection mechanism between the swash plate 18 and the piston 14 is extremely simple without requiring a connection mechanism such as a universal joint, and even a double-ended piston 14 can be driven without any problem, making it possible to use a swash plate compressor. The discharge capacity is not limited.

The rotating shaft 28 is located at the same distance from the centers of the cylinder bores 12F and 12R, and is rotatably supported by the cylinder block 10F and a cover body 42R, which will be described later, via bearings 30, 32, 34, and 36. The rotating shaft 28 has
A pin 38 perpendicular to the axis of rotation 28 mounts the swash plate 18 for rotation about the pin 33. Therefore, when the rotating shaft 28 is rotationally driven, the rotational motion of the swash plate 18 that rotates with it is converted into a reciprocating motion of the double-ended piston 14, and the angle of inclination of the swash plate 18 with respect to the rotating shaft 28 corresponds to Thus, the stroke of the double-ended piston 14 can be changed.

The outer end surfaces of cylinder blocks 10F and 10R are covered with lids 42F and 42R with valve plates 40F and 40R in between.
That is, the cylinder blocks 10F, 10R and the lids 42F, 42R constitute the housing of the variable displacement compressor. Lid body 42F, 42
R has suction chambers 44F, 44R and discharge chamber 46.
F, 46R is formed. Suction chamber 44F, 4
4R and the cylinder bores 12F, 12R are communicated via a suction valve (not shown), and similarly, the discharge chambers 46F, 46R are communicated with the cylinder bores 12F, 12R via discharge valves 48F, 48R. The cylinder blocks 10F, 10R are connected parallel to the rotating shaft 28 between the discharge chambers 46F and 46R, and between the suction chambers 44F and 44R.
are communicated with each other by a discharge passage 50 and a suction passage 52 formed through the outer periphery of the cylinder blocks 10F and 10R. It is communicated with the suction port 56. Note that a communication hole 60 allows communication between the swash plate chamber 58 that accommodates the swash plate 18 and the suction passage 52.
is formed in the cylinder block 10F forming a part of the outer wall of the swash plate chamber 58, and the suction chambers 44F, 44
According to the pressure difference between R and the suction passage 52 at a position communicating with the communication hole 60, the refrigerant flowing into the swash plate chamber 58 from the communication hole 60 flows into the bearings 32 and 3.
0, or through 34 and 36 etc., the suction chamber 4
It is designed to flow out to 4F or 44R.
That is, the communication hole 60 forms a refrigerant inflow passage.

At the center of the lid body 42R, there is a circular tubular projection 6 that supports one end of the rotating shaft 28 via a bearing 36.
2 protrudes toward the swash plate 18, and an adjustment member 66 is screwed into a threaded portion 64 formed on the outer peripheral surface of the protrusion 62. In addition, 67 is the protrusion 6
This is a hole that penetrates the side wall of No. 2 and communicates the inside of the projection 62 with the suction chamber 44R. The adjustment member 66 has a cylindrical shape with a larger diameter than the projection 62, and has a female thread formed on its inner peripheral surface to be screwed into the threaded portion 64.
It is adapted to be moved in the axial direction of the rotating shaft 28 by a drive motor 68 which is a rotational drive device. That is, a drive motor 68 having a worm 70 on its output shaft is provided on the outside of the lid 42R, and is rotatably supported by the lid 42R through the lid 42R, and is engaged with the worm 70 at one end. It includes a worm gear 72 and a suction chamber 44.
A transmission shaft 76 equipped with a pinion 74 is provided at the other end protruding into R, and the outer peripheral teeth formed on the outer periphery of the adjustment member 66 on the lid body 42R side are connected to the pinion 7.
4 is engaged. Therefore, when the adjusting member 66 is rotated relative to the lid 42R by being driven by the drive motor 68, the adjusting member 66 can be moved in the axial direction by the screwing action with the threaded portion 64. .

A cylindrical slider 78 is attached to the rotating shaft 28 so as to be movable in the axial direction of the rotating shaft 28, rotates together with the rotating shaft 28, engages with the adjusting member 66, and moves in the axial direction together with the adjusting member 66. is provided.

That is, as shown in FIG. 4, the slider 78 has a projection 80 that projects inwardly parallel to the axis
is provided on its inner peripheral surface, and the protrusion 80 forms a guide groove 8 provided in the axial direction on the outer peripheral surface of the rotating shaft 28.
2, allowing for movement in the direction of the tree. The flange member 84 formed on the adjustment member 66 side of the slider 78 is connected to the swash plate 1 of the adjustment member 66.
The slider 78 and the adjusting member 66 are engaged with an annular groove 86 formed on the inner circumferential surface of the 8-side via a pair of bearings 88, so that the slider 78 and the adjusting member 66 are relatively rotatably connected.

A pair of opposing brackets 90 are protruded from the swash plate 18 side of the slider 78, and one end of a link 92, which is a connecting member, is attached to the bracket 90 by a pin 9.
4, and the other end of the link 92 is pivotally connected by a pin 96 at an intermediate position between the center and the outer circumference of the swash plate 18. Therefore, the inclination angle of the swash plate 18 is changed according to the amount of movement of the adjustment member 66 in the axial direction, and the link 92 and the slider 7
8, the adjusting member 66, the screw portion 64, the drive motor 68, and the like constitute a swash plate inclination angle adjusting device.

According to such a swash plate inclination angle adjusting device, compared to a conventional device in which a piston or diaphragm operated by a refrigerant is provided with a mechanism for changing the inclination angle of the swash plate 18, the piston or diaphragm is operated by a refrigerant. This eliminates the need for parts such as a cylinder or diaphragm chamber with a large diameter for the swash plate compressor.
This has the advantage that the reduction in refrigerant discharge capacity can be completely eliminated.

The outer periphery of the adjustment member 66 is connected to the cylinder block 1.
It is hermetically fitted into a through hole 98 formed in the center of the 0R, and a groove 100 of a certain length communicating with the swash plate chamber 58 is formed parallel to the axis on the inner peripheral surface of the through hole 98. , an annular groove 102 is formed on the outer peripheral surface of the adjusting member 66, and a connection between the annular groove 102 and the suction chamber 4 is provided.
A groove 104 parallel to the axis that communicates with 4R is formed. The groove 100 and the annular groove 102 close when the adjusting member 66 is moved so that the angle of inclination of the swash plate with respect to the axis of rotation is minimized, in other words, the stroke of the double-ended piston 14 is maximized. When the angle of inclination increases and the stroke of the double-headed piston 14 begins to decrease, communication is established. Therefore, the groove 100, the annular groove 102, and the groove 104 form one outflow passage through which the refrigerant flows out from the swash plate chamber 58 to the suction chamber 44R, and the tip of the groove 100 and the annular groove 102 A valve is formed that opens the outflow passage as it moves toward the swash plate 18 side.

The cylinder blocks 10F, 10R and the lids 42F, 42R are fastened to each other by five bolts 106 passing through them.

In order to control the swash plate inclination angle of the variable capacity swash plate compressor configured as described above, a pressure sensor 110, which is a refrigerant state sensor, is provided on the lid body 42R, and the pressure in the suction chamber 44R increases. A cooling state signal SR that increases as the temperature increases is supplied to the control circuit 112, and a drive signal SD determined based on the cooling state signal SR is supplied from the control circuit 112 to the drive motor 68.

The control circuit 112 is configured as shown in FIG. 5, for example, and includes an adjustment resistor 113, and a setting circuit 114 that outputs a predetermined constant target signal ST by operating the adjustment resistor 113. A differential amplifier 116 that amplifies the difference between the target signal ST and the cooling state signal SR based on the signal and outputs a drive signal SD, and a swash plate for connecting the swash plate compressor to the engine, such as a clutch excitation voltage. As the compressor start signal SS disappears, the pressure sensor 110
It has a switching circuit 118 such as a relay that sets the output terminal of the switch to a negative power supply potential. Setting circuit 11
4 is set in advance so that a constant target signal ST corresponding to the refrigerant pressure in the suction chamber 44R in an ideal cooling state in the cooling system to which the swash plate compressor is applied is output. The differential amplifier 116 subtracts the cooling state signal from the setting signal ST, and when the difference is zero, it does not output the drive signal SD, but when the difference is negative, the stroke of the double-ended piston 14 increases. When the difference is positive, a drive signal SD is output that rotates the drive motor 68 in a direction in which the stroke of the double-ended piston 14 decreases. That is, the differential amplifier 116 receives the input signals ST and
The inclination angle of the swash plate 18 is controlled so that the difference between SR becomes zero. The drive motor 68 is constituted by a servo motor or the like that rotates forward or reverse depending on the sign of the drive signal SD, and stops when the drive signal SD is zero. Further, the switching circuit 118 is inserted in series with a pull-down resistor 120 between one power source and the output terminal of the pressure sensor 110, and is configured to open at the same time as the start signal SS is generated and close at the same time when the start signal SS disappears. The cooling status signal is output when the swash plate compressor finishes operating.
By forcibly reducing SR, the swash plate 18
The drive motor 68 is operated so that the inclination angle is the angle that minimizes the stroke of the double-ended piston 14, and the load on the rotating shaft 28 is always reduced when the swash plate compressor starts operating.

As described above, the swash plate inclination angle control device is configured by the pressure sensor 110, the control circuit 112, and the above-mentioned swash plate inclination angle adjustment device, so that the piston or diaphragm operated by the pressure of the refrigerant is tilted. Compared to conventional control devices that adjust the angle of inclination of the plate, there is no need for a large-diameter cylinder or diaphragm chamber to operate the piston or diaphragm, so the compressor becomes smaller and
It becomes possible to use a double-headed piston, and the problem of the refrigerant discharge capacity being halved can be resolved. Moreover, since the inclination angle of the swash plate 18 is controlled so that the cooling state signal SS representing the cooling state coincides with a predetermined constant target signal ST, it is possible to Variations in the control device caused by variations in parts are eliminated, and even if there are variations, adjustments for each product, which were extremely difficult, can be electrically made very easily.

The operation of the present invention will be explained below.

When the actuation signal SS is not generated, the rotating shaft 28 of the swash plate compressor is not rotationally driven, and the switching circuit 118 is closed. At this time, the cooling state signal input to the differential amplifier 116
Since SR is made small in the same way as the - power supply potential, the cooling state signal SR becomes much lower than the target signal ST, and a drive signal SD that reduces the stroke of the double-ended piston 14 is output from the differential amplifier 116 to the drive motor 68. . Therefore, the drive motor 68 rotationally drives the adjusting member 66 to move it toward the swash plate 18, so that the angle of inclination of the swash plate 18 is increased to approximately a right angle. FIG. 1 shows this situation.

Next, when the actuation signal SS is generated and the clutch etc. are connected, the swash plate 18 is driven to rotate together with the rotating shaft 28. At this time of startup, the inclination angle of the swash plate 18 is set to a substantially right angle and the stroke of the double-ended piston 14 is almost zero, so the rotational load on the rotating shaft 28 is the smallest, and for example, when the engine is rotating at low speed, the swash plate 18 Even when the compressor is connected, there is almost no rotational shock, and the life of the clutch friction plate is extended. Furthermore, the lubricating oil accumulated in the lower part of the swash plate chamber 58 is splashed off as the swash plate 18 rotates before the double-headed piston 14 reciprocates, so that each part is wetted before the swash plate 18 is operated under load. This is convenient for lubrication.

On the other hand, when the switching circuit 118 is opened at the same time as the activation signal SS is generated, the suction chamber 44 is normally opened.
Since the refrigerant pressure in R is high, the target signal ST is much lower than the cooling state signal SR, and the double-ended piston 14
The drive signal SD that maximizes the stroke of differential amplifier 1
16 to a drive motor 68. Therefore, the drive motor 68 rotationally drives the adjustment member 66 to move it toward the lid 42R, so that the swash plate 1
8 relative to the rotation axis 28 is reduced at a predetermined operating speed, and the adjusting member 66 is driven until the double-ended piston 14 reaches its maximum stroke. Therefore, the amount of refrigerant compressed and discharged by the double-ended piston 14 is maximized, and the cooling system (not shown) connected to the discharge port 54 and the suction port 56 is rapidly cooled. FIG. 3 shows this state.

Here, since the pair of shoes 20 inserted between the double-headed piston 14 and the swash plate 18 with the swash plate 18 sandwiched therebetween are formed so that their spherical centers coincide with each other, the swash plate 18 Regardless of changes in the inclination angle of
There are no gaps or twists between them.
Further, by moving the adjustment member 66 toward the lid body 42R, the groove 100 forming the outflow passage and the annular groove 102 and the groove 104 are closed, so that the communication hole 60 is closed.
The refrigerant that enters the swash plate chamber 58 and flows through the bearings 32 and 30 or the bearings 88, 3
4, 36 and the hole 67 to the suction chamber 44F or 44R.
The ratio of refrigerant passing through the swash plate chamber 58 to the refrigerant flowing into F and 44R is reduced. For this reason,
During high-load operation with a large stroke of the double-ended piston 14, the proportion of refrigerant from the high-temperature swash plate chamber 58 is suppressed, preventing the refrigerant in the suction chambers 44F and 44R from overheating, and increasing the volumetric efficiency (discharge capacity) of the swash plate compressor. ) is prevented from decreasing. In addition, during such high-load operation, the suction chambers 44F, 44R and the communication hole 60
Since the pressure difference between the opening of the swash plate chamber 58 and the suction passage 52 is large, the absolute amount of refrigerant passing through the swash plate chamber 58 is increased to an amount sufficient for lubrication.

Next, for example, when the temperature of the passenger compartment cooled by a cooling system (not shown) decreases and the cooling state becomes sufficient, the refrigerant pressure in the suction chambers 44F and 44R decreases, and the cooling state signal SR reaches the target level. Below the signal ST. Therefore, a drive signal SD corresponding to the difference between the signals SR and ST is supplied to the drive motor 68, and the drive motor 68 drives the adjustment member 66 so that the drive signal SD becomes zero. Therefore, the stroke of the double-headed piston 14 is shortened, in other words, the amount of refrigerant discharged is adjusted to be small. In this way, swash plate 1
8 is continuously controlled so that a necessary and sufficient refrigerant discharge amount can be obtained according to the cooling load. Therefore, when the required refrigerant discharge amount is small (light load), the refrigerant is unnecessarily compressed and discharged as the engine rotates, putting an unnecessary load on the engine and worsening the fuel consumption rate of the vehicle. There is no. Furthermore, if the compressor is filled with liquid refrigerant at startup, by starting the piston stroke from approximately zero, liquid compression can be prevented and liquid can be gradually expelled. This not only prevents booting but also
It also prevents damage to each part.

In the above operation, the refrigerant pressure in the suction chambers 44F and 44R further decreases, resulting in a low-load operation, and as the adjustment member 66 is moved toward the swash plate 18, the gap between the groove 100, the annular groove 102, and the groove 104 increases. Since the grooves 100 and 10 are communicated with each other, the grooves 100 and 10
2,104, the refrigerant in the swash plate chamber 58 flows into the suction chamber 44R, and the proportion of the refrigerant passing through the swash plate chamber 58 increases. In other words, the proportion of refrigerant passing through the swash plate chamber 58 increases as the load becomes lower, so that sufficient lubrication of the swash plate 18 etc. can be obtained even during low load high speed rotation when lubrication tends to be insufficient. be. At this time, the proportion of refrigerant passing through the swash plate chamber 58 increases and the volumetric efficiency of the swash plate compressor decreases, but this does not pose a problem since a large amount of refrigerant is not originally required during such low-load operation. .

Although the drawings showing one embodiment of the present invention have been described above, the present invention is applicable to other aspects as well.

For example, in the embodiment described above, when the swash plate 1
8 has the maximum inclination angle (approximately perpendicular to the rotation axis 28)
As shown in FIG. 1, the stroke of the double-headed piston 14 is approximately zero;
If the top clearance T of 4 exceeds 3 to 6 mm, the refrigerant gas will only be repeatedly compressed and re-expanded and will not be discharged.
3, when the swash plate 18 is not rotating, the stroke of the double-ended piston 14 is set so that the top clearance T is 3 to 6 mm or more, in other words, the stroke is shorter than the stroke in which the refrigerant is effectively compressed. The angle of inclination may also be adjusted. Even in such a case, the rotational load on the rotating shaft 28 is reduced compared to when the load is high, which has the effect of improving the fuel consumption rate of the engine and eliminating shock when the swash plate compressor starts operating. In addition, the inclination angle of the swash plate 18 and the adjustment member 66 are improved compared to the previous embodiment.
Also, since the moving distance of the slider 78 is reduced, there is an advantage that the axial shape of the swash plate compressor becomes smaller.

The cooling state sensor may be not only the pressure sensor 110 but also a temperature sensor disposed in the suction passage 52 or the passenger compartment to detect the temperature of the suction refrigerant or the temperature of the passenger compartment. There isn't.

The control circuit 112 is controlled by the input cooling state signal.
It may be configured with a simple amplifier that outputs a drive signal SD with a magnitude proportional to the magnitude of SR, and may be provided with an actuator that drives the adjustment member 66 with an operation amount proportional to the magnitude of the drive signal SD. .

In the embodiment described above, the grooves 100 and 104 forming the outflow passage are opened and closed according to the axial movement of the adjustment member 66, but they may also be configured to be opened and closed according to the relative rotation of the adjustment member 66. good. In such a case, since the amount of movement of the adjusting member 66 with respect to a change in the inclination angle of the swash plate 18 is large, there is an advantage that the amount of refrigerant flowing out can be easily controlled. Also, groove 1
Of course, 00 may be formed in the adjustment member 66 and the groove 104 may be formed in the inner peripheral surface of the through hole 98 of the cylinder block 10R.

Further, in the above-described embodiment, when the angle of inclination of the swash plate 18 with respect to the rotation axis increases and the stroke of the double-ended piston 14 begins to become smaller, the groove 100 and the annular groove 102 communicate with each other. Even if the angle of inclination of the plate is the minimum, it may be possible to provide a slight communication, and as the angle of inclination increases, the flow area increases.

Furthermore, in the embodiment described above, the double-ended piston 1
4 is used, but a single-headed piston with only one end slidably fitted into the cylinder bore may be used.

The above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken from the side in FIG. 1. FIG. 3 is a diagram illustrating the operation of the embodiment of FIG. 1. 4 is a perspective view showing the slider of the embodiment shown in FIG. 1. FIG. FIG. 5 is a circuit diagram showing the electrical configuration of a control device applied to the embodiment of FIG. 1. {10F, 10R: cylinder block, 42
F, 42R: Lid} (housing), 12F, 12
R: cylinder bore, 14: double-ended piston (piston), 18: swash plate, 58: swash plate chamber, 60: communication hole (inflow passage), 66: adjustment member, {100, 10
4: groove, 102: annular groove} (outflow passage), {10
0: groove, 102: annular groove} (valve).

Claims (1)

[Scope of Claims] 1. A swash plate attached to a rotating shaft with a variable inclination angle, a swash plate chamber housing the swash plate, and a plurality of cylinder bores having centers on the same circumference around the rotating shaft. a housing formed with a piston, a piston that is fitted into each of the cylinder bores and sucks in and discharges refrigerant by reciprocating in a stroke corresponding to the inclination angle of the swash plate, and a piston that is rotatable relative to the swash plate. an adjusting member connected to the housing and changing the inclination angle of the swash plate by moving relative to the housing;
In a variable displacement swash plate compressor of a type in which a portion of the refrigerant is passed through the swash plate chamber through an inflow passage and an outflow passage provided in the swash plate chamber, a direction in which the stroke of the piston of the adjustment member is decreased. A valve whose flow cross-sectional area is increased by movement of the piston is provided in the outflow passage, and the smaller the stroke of the piston, the larger the proportion of the refrigerant passing through the swash plate chamber. Capacitive swash plate compressor.