JPH0233477A - Variable-displacement swash plate type compressor - Google Patents

Abstract

PURPOSE:To facilitate assembling by setting the pressure receiving area of a slide control body so that the pressure in a control pressure chamber applied to the slide control body and the pressure applied to the slide control body from the opposite side to the control pressure chamber are balanced at the time of the maximum displacement. CONSTITUTION:The pressure receiving area of a slide control body 34 is set so that the pressure in a control pressure chamber 23a applied to the slide control body 34, i.e., the control pressure equal to the discharge pressure, and the pressure applied from the opposite side to the control pressure chamber are balanced when the ratio Ps/Pd between the intake pressure Ps and the discharge pressure Pd is the maximum compression ratio generated in a refrigerant circuit, e.g., at the maximum displacement when Ps/Pd=3/31. No stopper is required to restrict the position of the slide control body 34 to set the swash plate inclination angle at the time of the maximum displacement to the preset value, thus no alignment of the stroke and top clearance is required at the time of assembling. The time and labor required for assembling can be sharply reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable displacement swash plate compressor equipped with a double-ended piston.

[Prior Art] A variable displacement compressor that combines the cooling efficiency of a double-headed piston type pressure fim is disclosed in Japanese Patent Laid-Open No. 162782/1982. In this compressor, the swash plate is supported so that it can rotate integrally with the rotating shaft and swing back and forth, and the inclination of this swash plate is controlled based on suction pressure information that reflects the cooling load. ing. However, since the center of oscillation of the swash plate is set at a fixed position on the rotation axis, the compression stroke and E dead center of the double-headed piston fluctuate depending on the swash plate inclination angle in both the front and rear compression chambers. The plate inclination angle is 0 11! II
Substantial compression and discharge cannot be performed in the compression action area on the small volume side close to .

A variable capacity compressor that improved this drawback was developed in Japanese Patent Application Laid-Open No. 63-14.
It is disclosed in Japanese Patent No. 7977. In this compressor, the center of swing of the swash plate is set at a radial position of the rotating shaft corresponding to the cylinder bore of the cylinder block that accommodates the double-headed piston, and the center of rotation of the swash plate is variable. Therefore, the top dead center of the compression stroke in the cylinder bore on one side of the double-headed piston is defined at a fixed position, and substantial compression and discharge are performed even in the compression action area on the small capacity side where the swash plate inclination angle is close to the military system.

The swash plate inclination is determined by the swash plate rocking force due to the pressure in both the front and rear cylinder bores via the sliding control body and the swash plate that change the volume of the control pressure chamber connected to the discharge pressure region or the suction pressure region and the pressure in the control pressure chamber. The sliding control body is slidably supported on the rotating shaft.

The force exerted on the rotating shaft by the swash plate, which oscillates due to this pressure opposition, is received by the guide hole on the rotating shaft side via the guide pin on the swash plate side, and the swash plate is stopped by the guide relationship between the guide pin and the guide hole. The tilt angle is controlled.

[Problems to be Solved by the Invention] In the conventional device described above, in order to prevent an excessive load from being applied to the thrust bearing that carries the thrust load at maximum capacity, the sliding control body is brought into contact with a stopper. regulated the location of

However, when regulating the position of the sliding control body at maximum capacity by abutting it against a stopper, assembly is sometimes done by bringing the sliding control body into contact with the stopper in order to adjust the stroke and top clearance. There is a problem in that it is necessary to shave the surface, which takes a lot of effort and time.

In addition, with the conventional pressure unit, it is not possible to monotonically increase the control pressure at the maximum capacity side, and in this region it is necessary to use a correction spring to correct the direction in which the control pressure is raised. The structure in which a correction spring is interposed between the rotating shaft and the sliding control body complicates the R shrine.

Also, if the ratio between the discharge pressure and the suction pressure, that is, the compression ratio is low, the spring force of the correction spring is increased to reduce the control pressure.・
, baldness needs to be corrected. In this way, when using a correction spring to raise the control pressure on the large capacity side, the start time of the capacity change from 1100% to the low capacity side is delayed, that is, the pressure in the control pressure chamber There is a problem in that the movement of the sliding control body does not start in synchronization with the decrease in pressure even though the pressure decreases, and a region insensitive to the control pressure appears.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to eliminate the need to sometimes adjust the stroke and top clearance during assembly, and eliminate the dead area on the maximum capacity side to control sliding. It is an object of the present invention to provide a variable capacity heavy type swash plate type compressor which improves the followability of the body and improves the capacity controllability.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a control pressure chamber for capacity control that can be switched to a pressure equivalent to the discharge pressure or suction pressure, and also provides a control pressure chamber for capacity control that can be switched to a pressure equivalent to the discharge pressure or suction pressure. A sliding control body is supported on the rotating shaft so as to be slidable in the axial direction of the rotating shaft, and the sliding control body is shaped like an ellipse so that suction pressure acts on the surface opposite to the control pressure chamber, and prevents tilting caused by compression of the refrigerant gas. The plate rocking force and the pressure in the control pressure chamber are opposed to each other via the swash plate and the sliding control body, and a guide pin is installed on the swash plate side that is swung by this opposition, and a guide pin is installed on the rotating shaft side. A guide hole having a guiding relationship with the guide pin described in mf is provided, and the swash plate inclination angle is increased as a guide curve that defines the shape of the large volume side of the guide hole with the displacement position of the guide pin in the axial direction of the rotating shaft as a variable. A monotonically increasing and downwardly convex curve is adopted for the displacement of the guide pin, and the pressure in the control pressure chamber applied to the sliding control body and the activity of the control body at the maximum capacity at the maximum compression ratio that occurs in the refrigerant circuit are The pressure receiving area of the sliding control body was set so that the pressure applied from the side opposite to the control pressure chamber was balanced.

[The swash plate inclination angle varies depending on the pressure difference between the swash plate rocking force due to the pressure difference in the front cylinder bore and the rear cylinder bore and the pressure in the control pressure chamber.The swash plate acting force on the zero rotation axis is The receiver is fixed in the guide hole on the rotating shaft side via the guide pin on the swash plate side, and the swash plate inclination angle is also controlled by the guide relationship between the guide hole and the guide pin. The guide pin is displaced along the guide curve, but on the high-capacity side, the guide curve is a curve that monotonically increases and is convex downward in the direction of increasing the swash plate inclination angle. The pressure increases monotonically with respect to the displacement of the guide pin in the direction of increasing swash plate inclination I\. In addition, the pressure in the control pressure chamber that is applied to the sliding control body at maximum capacity (at 100% capacity), that is, the discharge pressure, is balanced with the pressure that is applied to the active control body from the side opposite to the control pressure chamber, so the position of the active control body is held at a predetermined position even without a stopper that restricts displacement of the sliding control body in the direction of the rotation axis. This holds true even when the compression ratio is changed, except in the case of low compression ratios, and even in the case of low compression ratios, the required control pressure at maximum capacity is below the discharge pressure and takes a value close to the discharge pressure. , there is no problem in control even if there is no stopper, and since there is no correction spring that corrects raising the control pressure on the maximum capacity side, there is no problem with sliding against changes in control pressure when lowering the capacity from the maximum capacity. The followability of the dynamic control body is improved, there is no dead area, and controllability is improved.

[Example] An example embodying the present invention will be described below with reference to the drawings.

As shown in Fig. 1.2, a front housing 2 and a rear housing 3 are fixedly connected to both the front and rear end surfaces of the cylinder block 1, and a rotating shaft 4 is connected to the front housing 2 and the cylinder block 1 at the front shaft portion. It is rotatably supported via 4a. On the inner end side of the front shaft section 4a, a rear shaft section 4b is provided with a bearing plate 5 and a connecting body 6.
Guide holes 6a, 7a are formed in the connecting body 6.7, and a thrust bearing 8 is interposed between the plate 5 and the inner end of the cylinder block 1. equipped.

A guide bushing 9 is slidably fitted into the rear shaft portion 4b, and shaft pins 10 (only one shown) are provided protruding from both left and right sides of the base end of the guide bushing 9. A swash plate 11 is rotatably supported. A bridge lla is formed on the front surface of the swash plate 11, and a guide pin 12 is fitted in the middle of the bridge so as to protrude to both sides.
3 is installed. Bridge lla connects both connectors 6.
7, and both rotors 13 are connected to the connecting body 6.7.
As a result, the swash plate 11 rotates together with the rotating shaft 4 within the slant 4'l chamber 14.

The rotating shaft 4, the swash plate 11, and the guide bush 9 are connected to each other through a guiding relationship between the guide pin 12 and the guide holes 6a, 7a, and a rotatable relationship between the swash plate 11 and the guide bush 9, which is slidable back and forth. ing. As a result, the swash plate 11 can swing as the guide bush 9 slides, and the center C of this swing is set on the periphery side of the swash plate 11. A double-headed piston 15 is accommodated in a plurality of front cylinder bores 1a and rear cylinder bores 1b that are formed correspondingly on the rotation locus of the swash plate 11.
These plural double-headed pistons 15 and swash plate 11 are connected to the shoe 1.
6.17, and the double-headed piston 15 reciprocates back and forth as the swash plate 11 rotates.

Between the cylinder block 1 and both the front and rear housings 2.3, there is a partition plate 18.19 and a valve formation plate 20.2.
1 is interposed, and a suction chamber 22.23 and a discharge chamber 24.25 are defined in both the front and rear housings 2.3. The refrigerant gas in the suction pipe 26 forming the external refrigerant gas circuit flows through the inlet 27 as the double-ended piston 15 reciprocates.
It enters the inclined root chamber 14 from the front side, passes through the front side suction passage 28, the rear side suction passage 29, the front side suction chamber 22, the rear side suction chamber 23, the suction boats 18a and 19a opened and closed by the suction valves 20a and 21a, and then the front side. It is sucked into the compression chamber Pf and the rear side compression chamber Pr and is subjected to a compression action. And both compression chambers Pf.

Refrigerant gas discharged from Pr to both ridge chambers 24.25 via discharge boats 18b and 19b opened and closed by discharge valves 30.31 is discharged from outlet 33 via discharge passage 32.

The swing center C of the swash plate 11 is set on the peripheral edge of the swash plate 11, and is also set around the rear cylinder bore 1bW, so that the top dead center of the compression stroke of the double-headed piston 15 in the front compression chamber Pf is Although it varies depending on the inclination angle of the swash plate 11, the compression stroke - top dead center of the double-headed piston 15 in the rear side compression chamber Pr is defined at the fixed position shown in FIG.

Therefore, in the front side compression chamber Pf, when the swash plate inclination is small, compression and engraving without substantial suction and discharge are performed, but in the rear side compression chamber Pr, where the top dead center of the compression stroke is constant. Regardless of the inclination angle of the swash plate 11, a substantial compression action accompanied by suction and discharge is performed.

A sliding control body 34 having a cylindrical shape with a bottom and having a flange portion 34a at the rear end is fitted into the rear suction chamber 23 so as to be slidable in the front and rear direction. The control pressure chamber 23a is partitioned into a control pressure chamber 23a. The sliding control body 34 has its cylindrical portion 34b supported by the guide bush 9 via a thrust bearing 35 and a radial bearing 36 so as to be relatively rotatable. As a result, the pressure in the control pressure chamber 23a is transmitted through the sliding control body 34, the guide bush 9, and the swash plate 11 to the swash plate rocking force generated by the pressure in the front side compression chamber Pf and the pressure in the rear side compression chamber Pr. to counter.

The sliding control body 34 controls the compression ratio, that is, the suction pressure Ps and the discharge pressure Ps.
The ratio Ps/Pd of d is equal to the maximum compression ratio occurring in the refrigerant circuit, for example, the pressure in the control pressure chamber 23a that is applied to the sliding control body 34 at the maximum capacity at Ps/Pd=3/31, that is, the discharge pressure. The pressure receiving area of the sliding control body 34 is set so that the control pressure and the pressure applied to the sliding control body 34 from the side opposite to the control pressure chamber are balanced.

The control pressure chamber 23a, the rear side discharge chamber 25 carrying the discharge pressure head, the swash plate chamber 14 in the suction pressure region, and the suction pipe 26 are connected to a control valve mechanism (not shown), and the front and rear displacement of the sliding control body 34 is controlled by fluctuations in the suction pressure within the suction line 26.

That is, by opening and closing a valve in the capacity control valve mechanism based on the suction pressure in the suction pipe line 26, the control pressure chamber 23a is controlled to be switched to a high pressure equivalent to the discharge pressure or a low pressure equivalent to the suction pressure, and the swash plate 1
1 is swingably arranged between a maximum tilt position shown in FIG. 1 and a minimum tilt position (not shown).

The swash plate 11 swings through the guide hole 6a on the rotating shaft 4 side.

7a and the rotor 13 on the side of the swash plate 11, the guide hole 6a is guided through the metal engraving and provides this guiding effect.

7 a is oblique to the axis 1 of the rotating shaft 4 .

The displacement curve of the guide bin 12, that is, the guide hole 6a.

As shown in FIG. 3, the guide curve S of 7a is calculated using the displacement position X of the guide bin 12 in the axial direction as a variable.
o has an inflection point S0, and on the large capacity side x0≦X≦x1, the slope α of the tangent to the guide curve S is a positive monotonically increasing curve that increases as the variable X increases, that is, in the direction of increasing swash plate inclination. A monotonically increasing and downwardly convex curve is used for the displacement of the guide bin 12, and when 0≦X≦x0, the guide curve S
A circular arc is used in which the slope α of the tangent line is a negative monotonically increasing slope that decreases as the variable X increases. The displacement position X of the guide bin 12 is not shown by a solid line in FIG. 3, but the position of the shaft bin 10 is
That is, this corresponds to the case where the swash plate inclination angle β is maximum, and the discharge capacity is maximum. The displacement position x=O of the guide bin 12 is indicated by a chain line on the right side of FIG. 3, and corresponds to the position of the shaft pin 1O, that is, the case where the swash plate inclination angle β is the minimum, and the discharge capacity is the minimum.

Next, we will explain the operation of the compressor configured as described above.0 When the electromagnetic clutch (not shown) is connected and the rotational driving force of the engine is transmitted to the rotating shaft 4, the swash plate 11 is integrated with the rotating shaft 4. Rotate to . Since the swash plate 11 is inclined with respect to the rotating shaft 4, the rotation of the swash plate 11 is accompanied by rocking. The rocking of the swash plate 11 causes the shoes 16 and 17 to
is transmitted to the double-ended piston 15 via the double-ended piston 1.
5 performs reciprocating motion within the cylinder bores 1a, lb.

The discharge capacity of the compressor is variably controlled by changing the inclination angle of the swash plate 11. FIG. 1 shows a state in which the tilt angle of the swash plate 11 is at its maximum, and in this state, the discharge capacity of the compressor is at its maximum.

At this time, the control pressure in the control pressure chamber 23a is applied to the back side of the sliding control body 34, and the front side compression chamber P is applied to the front side.
The swash plate rocking force generated by the pressure in f and the pressure in the rear pressure chamber Pr is added to the suction pressure. The pressure receiving area of the sliding control body 34 is set so that when the discharge pressure is applied as the control pressure at the maximum capacity, the pressure receiving area of the sliding control body 34 is set so that both are balanced.
is moved into position and held there.

In other words, there is no need for a stopper to restrict the position of the sliding control body 34 at maximum capacity, so there is no need to sometimes adjust the stroke and top clearance when assembling the compressor, reducing the time and labor required for assembly. will be significantly reduced.

When the maximum compression ratio that occurs in the circuit, that is, the suction pressure Ps and the discharge pressure Pd, is expressed in units of < kgf /dlabs, the ratio is Ps/Pd = 3/31 and the balance Pc at 100% capacity (required control A diagram showing the relationship between the balance Pc and the capacity ratio when the pressure receiving area of the activity control body 34 is set so that the pressure) is equal to the discharge pressure Pd is shown in FIG. 4(f).The balance Pc is the capacity ratio. It monotonically decreases from 100% as the capacity ratio decreases. For the active control body 34 having this pressure-receiving area, the value of the compression ratio P s / P d is varied, and the relationship between the balance Pc and the capacity ratio for each compression ratio is obtained by simulation. The results are shown in Fig. 4(a). ) to (e), the value of P s / P d is 3/26.

In the case of large values such as 3/21 and 3/16, the balance Pc at 100% capacity is equal to the discharge pressure Pd, as in the case of 3/31.
Even when the compression ratio is comparatively small, such as 3/11.3/8, the balance Pc at 100% capacity is below the discharge pressure and takes a value close to the discharge pressure. That is, at the maximum capacity at a certain compression ratio on the high compression ratio side, the sliding control body 311
By setting the pressure receiving area of the sliding control body 34 so that the pressure inside the control pressure chamber 23a applied to the control pressure chamber 23a and the pressure applied to the sliding control body 34 from the side opposite to the control pressure chamber are balanced, almost all compression ratios can be adjusted. The balance Pc at maximum capacity becomes equal to the discharge pressure at that time. Therefore, a stopper for regulating the position of the activity control body 34 is not required.

Moreover, as shown in FIGS. 4(a) to (f), the balance Pc monotonically increases with the increase in capacity ratio at each compression ratio, and the control pressure by the correction spring in the maximum customer volume side region Since the pressure is not pulled up, there is no insensitive area to changes in control pressure, and the movement of the active control body 34, that is, the change in capacity, can be performed with good followability in response to changes in control pressure.

Note that the present invention is not limited to the above embodiments,
For example, when the compressor starts operating from a stopped state with the swash plate inclination at the minimum side, a return spring 37 is installed in the control pressure chamber 23a to eliminate the inconvenience that the swash plate 11 is difficult to move to the maximum inclination side. This spring, which may be interposed, does not raise the control pressure on the maximum capacity side, so that the capacity change from the maximum capacity to the small capacity side is performed smoothly in the same way as in the previous embodiment.

[Effects of the Invention] As detailed above, according to the present invention, the activation is performed so that the pressure in the control pressure chamber applied to the active control body at maximum capacity is balanced with the pressure applied to the sliding control body from the side opposite to the control pressure chamber. Since the pressure-receiving area of the control body is set, there is no need for a stopper to regulate the position of the sliding control body so that the swash plate inclination angle at maximum capacity is a predetermined value. Since there is no need to adjust the clearance, the time and labor required for assembly are significantly reduced. In addition, at maximum capacity, the active control body is held in a predetermined position only by pressure balance, so when the control pressure is changed to change the capacity, the sliding control body follows the change in control pressure and smoothly moves. This has the excellent effect of improving controllability by eliminating areas insensitive to control pressure.

[Brief explanation of the drawing]

1 to 4 show an embodiment embodying the present invention, in which FIG. 1 is a line sectional view of the compressor, FIG. 2 is a sectional view taken along line A-A in FIG. The figure is a diagram for explaining the guide hole and the guide curve, and FIGS. 4(a) to 4(f) show the relationship between balance Pc (required control pressure) and capacity ratio when the compression ratio is changed. FIG. 5 is a partial sectional view of a modified example. Cylinder block 1, rotating shaft 4, guide hole 6a. 7a, swash plate 11, guide bin 12, double-ended piston 15,
Control pressure chamber 23a, sliding control body 34, guide music &lS. Patent applicant: Toyota Automobile Co., Ltd.! 111m Manufacturing Representative Patent Attorney On 1) Hiroshi Yoshihiro i11. Ratio (%) Capacity ratio (%) Capacity ratio (%) Capacity ratio (%) Capacity ratio (%) Figure 4 (f) Group O0 Capacity ratio (%)

Claims (1)

[Claims] 1. A rotary shaft is rotatably housed and supported in a cylinder block that reciprocably accommodates a double-headed piston, and a swash plate for reciprocating the double-headed piston is mounted on the rotary shaft and is not relatively rotatable and moves back and forth around its periphery. It is supported so as to be swingable, and its swing center position is set near the rear cylinder bore, and the reciprocating movement area of the double-headed piston is set in the rotation area of the swing center due to the rotation of the rotating shaft, and the swing center position is set near the rear cylinder bore. In a swash plate compressor with the top dead center of the compression stroke at a fixed position, a control pressure chamber for capacity control that can be switched to a pressure equivalent to discharge pressure or suction pressure is provided, and a sliding mechanism that changes the volume of the control pressure chamber is provided. A control body is supported on the rotating shaft so as to be slidable in the axial direction thereof, and suction pressure is applied to a surface of the sliding control body opposite to the control pressure chamber, and the swash plate rocking force generated by refrigerant gas compression and The pressure in the control pressure chamber is opposed to the pressure in the control pressure chamber via the swash plate and the sliding control body, and a guide pin is attached to the swash plate side that is swung by this opposition, and
A guide hole having a guide relationship with the guide pin is provided on the rotating shaft side, and a swash plate is formed as a guide curve that defines the shape of the large capacity side of the guide hole with the displacement position of the guide pin in the axial direction of the rotating shaft as a variable. A downwardly convex curve that increases monotonically with respect to the displacement of the guide pin in the direction of increasing inclination angle is adopted, and the pressure in the control pressure chamber applied to the sliding control body and the sliding pressure are applied to the sliding control body at the maximum capacity at the maximum compression ratio that occurs in the refrigerant circuit. A variable capacity swash plate compressor in which the pressure receiving area of the sliding control body is set so that the pressure applied to the sliding control body from the side opposite to the control pressure chamber is balanced.