JP3125461B2 - Variable displacement compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement compressor suitable mainly for vehicle air conditioning.

[0002]

2. Description of the Related Art A conventional compressor of this type is disclosed in
The one disclosed in JP-A-16177 is known. As shown in FIG. 3, the compressor includes a crank chamber 52 formed in a housing 51, a rotor 54 connected to a drive shaft 53 in the crank chamber 52, and a hinge mechanism 55 attached to the rotor 54.
A swash plate 56 supported through the swash plate, a swing plate 57 attached with the rotation thereof being restricted along the swash plate 56,
A plurality of pistons 59 that reciprocate in the bore 58 due to the swing of the swing plate 57, a suction chamber 60 that supplies fluid into the bore 58, a discharge chamber 61 from which compressed fluid is discharged, and a crank chamber 52 A valve means 62 is provided in a bleed passage 63 connecting the suction chamber 60 and the suction chamber 60, and a valve means 62 for sensing the pressure in the suction chamber 60 and adjusting the opening degree of the bleed passage 63 is constituted as a main element. The hinge mechanism 55 for connecting the rotor 54 and the rotary swash plate 56 has a form in which an elongated hole is provided on the rotor 54 side, and a pin mounted on the rotary swash plate 56 is inserted into the elongated hole. The rotary swash plate 56 is supported by the rotor 54 so as to be tiltable within the range of the length of the long hole.

According to such a configuration, the following operation can be obtained. That is, when the opening degree of the bleed passage 63 is adjusted by the operation of the valve means 62 in accordance with the suction pressure and the crank chamber pressure is changed as needed by the blow-by gas leaking from the bore 58, the force applied to the back surface of the piston 59 At the same time, the equilibrium point of the moment acting on the rotary swash plate 56 also changes, and the tilt angles of the rotary swash plate 56 and the swinging plate 57 change.
The volume of fluid taken into 8 is controlled. That is, the suction pressure is controlled by such a capacity variable mechanism so as to be a preset value.

[0004]

According to the above-described variable capacity mechanism, as the suction pressure is reduced, the valve means 6 is increased.
2 operates to reduce the degree of opening of the bleed passage 63, and controls to increase the crank chamber pressure to reduce the capacity of the compressor. Even if the compressor 63 is completely closed and the compressor capacity is further reduced due to the further increased crankcase pressure, the lower limit is restricted to a preset minimum capacity. This is because effective compression work is not performed in an extremely small capacity range at or near zero, and the capacity return control based on the pressure difference between the suction pressure and the crank chamber pressure becomes practically impossible. Further, in recent compressors that require lubrication of each sliding portion in the machine based on oil particles mixed in the refrigerant, seizure and reduction in durability caused by insufficient refrigerant (lubrication) also have to perform lower limit control of capacity control. This can be pointed out as one of the causes.

Therefore, since the minimum capacity of the compressor is regulated as described above, the electromagnetic clutch is disconnected for reasons such as protection of the compressor and prevention of frost of the evaporator depending on the use environment of the vehicle air conditioner such as a cold region. It is necessary to stop the compressor via. In other words, the electromagnetic clutch coupled to the compressor is widely used as an essential component of the current vehicle air conditioner, but the impact of the shock at the start on the driving feeling is not limited to the electromagnetic clutch. It is also difficult to overlook the fact that the efficiency of the alternator for supplying power is unexpectedly low, and the load on the engine is correspondingly increased. In other words, if the electromagnetic clutch can be omitted, it will be easily understood that not only the contribution to the pursuit of fuel saving but also the weight reduction of the compressor will bring about an epoch-making result.

An object of the present invention is to solve the problem that the electromagnetic clutch can be omitted by protecting the compressor and suppressing supercooling.

[0007]

In order to solve the above-mentioned problems, the present invention provides a crank chamber, a drive shaft extending in the crank chamber and rotatably supported, and a rotor fixed to the drive shaft. A rotary swash plate pivotally supported by a sleeve fitted to the drive shaft and supported by the rotor via a hinge mechanism, and linked to the rotary swash plate to rotate the swash plate. A plurality of pistons that move directly in each bore based on the movement, a suction chamber that supplies fluid into the bore, a discharge chamber in which fluid compressed in the bore is discharged, and a pressure in the crank chamber. A control valve for adjusting the pressure difference between the suction chamber pressure and the crank chamber pressure by the control valve, and changing the inclination angle of the rotary swash plate to vary the intake volume of the fluid into the bore. In the variable displacement compressor described above, the compressor is connected to the drive shaft. A gear pump for pressure-feeding oil input, a push-and-retract member capable of controlling the displacement of the rotary swash plate via the sleeve by urging means that opposes the oil pressure and spring force of the gear pump, and an evaporator. Valve means for selectively controlling refueling to the urging means in response to the outlet pressure of the pushing member, forcing the rotary swash plate into the restricted capacity posture at the advanced position of the pushing member, and at the retracted position thereof. A new configuration is adopted in which the rotary swash plate is configured to allow a zero capacity attitude.

[0008]

When the compressor is at rest with the engine, the valve means is kept closed by the pressure balance in the machine, and is pushed by the urging means to which only the spring force acts unilaterally. The member advances and regulates the movement position of the sleeve, forcing the rotary swash plate to have a capacity posture equal to or larger than the regulated capacity. When the drive shaft is rotated following the start of the engine from this state, the compressor starts the compression work based on the inclination angle of the rotary swash plate simultaneously with the activation of the gear pump directly connected to the drive shaft. When the compression work is started in this way, the outlet pressure of the evaporator acting on the valve means in a form balanced with the crank chamber pressure is reduced, and the valve means is switched to the open state by the generated differential pressure. Therefore, the discharge oil from the gear pump is supplied to the urging means via the valve means, and the hydraulic pressure overcomes the opposing spring force to immerse the pushing member, and thereafter, the control according to the cooling load is performed. By operating the valve, the rotary swash plate is controlled to a freely variable range. And if the cooling load decreases to the state where cooling is unnecessary, the rotating swash plate with the sleeve is displaced to the zero-capacity posture without being hindered by the immersed pushing member, and the compression work is inevitable. Stopped.

When the compressor is practically disabled as described above, the internal pressure of the compressor is soon balanced by, for example, the extraction of high-pressure refrigerant through the bleed passage, and the valve is balanced by the balance between the crank chamber pressure and the outlet pressure of the evaporator. Since the means is switched to the original closed state, the urging means whose hydraulic pressure has been cut off, the spring force rises and urges the pushing member to advance, and the rotating swash plate returns to the regulated capacity posture via the sleeve. Force return. Thus, when the compression work of the regulated capacity is resumed, the pushing member is immediately immersed with the reversing operation of the valve means and the urging means, and the compressor is set to zero or zero as long as the cooling unnecessary state is continued. Maintaining a near-zero ultra-small capacity condition to reduce excessive cooling and power consumption while at the same time providing compressor protection with lubricating oil supply through minimal compression work. The discharge oil of the gear pump is always supplied to the shaft sealing chamber via a relief valve and an oil hole provided in the drive shaft, and is used for lubrication of the shaft seal which is particularly concerned.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the drawing, a front housing 2 is connected to a front end of a cylinder block 1 which is a main body of the compressor, and a rear housing 3 is connected to a rear end via a valve body 4. In a crank chamber 5 formed by the cylinder block 1 and the front housing 2, a drive shaft 6 interlocked with an engine (not shown) is housed. The drive shaft 6 is rotatably supported by bearings 7 and 8. . The cylinder block 1 is provided with a plurality of bores 9 arranged in parallel around the drive shaft 6, and each of the bores 9 is fitted with a piston 10.

A rotor 11 cooperating with the drive shaft 6 is fixed on the drive shaft 6 in the crank chamber 5, and a sleeve 12 having a spherical bearing surface is fitted so as to be rotatable and slidable. . An opposing spring 13 is interposed between the stepped portion of the drive shaft 6 and the sleeve 12 to urge the sleeve 12 rearward, and the sleeve 12 is fitted with the spherical bearing surface. The rotating swash plate 14 having the inner surface of the ball band is pivotally supported to be tiltable. The counter spring 13 shown in FIG.
In the most contracted state, the regulating surface 14a inclined to the lower rear surface of the rotating swash plate 14 abuts against the inner end surface of the rotor body 11, and the maximum inclination angle of the rotating swash plate 14 is regulated. The piston 9 is moored to the disk surface formed on the outer periphery of the rotary swash plate 14 via hemispherical shoes 5,5.

On the other hand, an arm 16 constituting a hinge mechanism protrudes rearward from the outer peripheral edge of the rotor 11, and the distal end of the arm 16 has a support shaft 1 perpendicular to the axis.
7 is rotatably inserted. A guide pin 1 penetrates through the support shaft 17 in the radial direction with the arm 16 interposed therebetween.
The guide pins 18 are fixed at the base ends thereof and extend therefrom.
Is slidably inserted into an articulation portion 19 formed on the front side of the rotary swash plate 14.

Reference numeral 20 denotes a control valve which is built in, for example, the rear housing 3 and adjusts an opening degree of an air supply passage 23 connecting the discharge chamber 22 and the crank chamber 5 in response to the pressure in the suction chamber 21. The control valve 20 has a bellows 20a in which a spring or a gas body of a predetermined pressure is sealed, and a valve body 20b coupled to the bellows 20a, and the bellows 20a expands and contracts against the suction chamber pressure, The opening and closing of the valve seat 23a of the air supply passage 23 is controlled via the valve body 20b. Reference numeral 24 denotes a bleed passage that constantly connects the crank chamber 5 and the suction chamber 21.

The ultra-small capacity control mechanism which is the most characteristic configuration of the present invention will be described below. That is, a gear pump (trochoid type) 30 directly connected to the end of the drive shaft 6 is housed in the rear housing 3, and the suction port of the gear pump 30 has a crankcase 5 through an oil passage 31.
The enclosed oil is introduced. The discharge port of the gear pump 30 is connected to the rear housing 3 and the valve plate 4.
The discharge port on the rear housing 3 side is provided with a relief valve 32 and an oil hole 33 provided inside the drive shaft 6.
, And a discharge port on the valve plate 4 side is described later via a pressure guide path 35 formed from the valve plate 4 to the cylinder block 1. It is connected to the valve means.

A stepped through-hole having a different diameter is formed in the rear axial center of the cylinder block 1, and a stopper 41 is press-fitted into a cylindrical shape in the large-diameter hole at the rear. The rear end of the drive shaft 6 is supported by the mounted bearing 8 described above. In front of the stopper 41, a flange portion of a pushing member 42 having a hollow shape is tightly slidably fitted to the large-diameter hole via a sealing element, and a body portion is similarly disposed at the bottom of the large-diameter hole. A working chamber 44 is formed between the lip seal 43 and the flange of the pressing member 42 through the lip seal 43. The pushing member 42 is constantly urged forward by a coil spring 45 interposed between the pushing member 42 and the outer end surface of the stopper 41. It is regulated by interference with 41a. FIG. 2 shows the advanced state of the pushing member 42, and the front end of the pushing member 42 at the time of the advance moves to the rotary swash plate 14 through the abutment with the sleeve 12 so as to have the restricted capacity (5-1).
It is adjusted so that the posture (0% returnable lower limit capacity) posture can be forced. 46 is the working chamber 44 and the crank chamber 5
A return oil orifice that communicates with

The cylinder block 1 is provided with a bottomed long hole-shaped valve chamber 51 extending along the large-diameter hole.
Has a small hole communicating with the crank chamber 5 and a mouth end extending through the valve plate 4 and the rear housing 3.
2, the valve chamber 51 is connected to the outlet of the evaporator E, and a part of the valve chamber 51 is also connected to the working chamber 44 through a through hole. The valve chamber 51 has a built-in spool valve body 53 whose both ends are supported by an equilibrium spring. When the crank chamber pressure led to the valve chamber 51 and the evaporator outlet pressure are balanced, the spool valve body 53 is provided. Is the impulse line 3
5 and the working chamber 44, while the spool valve element 53 is in a state where a pressure difference is generated between the pressure and the crank chamber pressure based on the decrease in the evaporator outlet pressure, the spool valve element 53 is connected to the pressure guiding passage 35 and the working chamber. Operate to allow communication with Thus, the spool valve body 53 for selectively controlling the oil supply to the working chamber 44 constitutes the valve means according to the present invention, and the spring force of the coil spring 45 acting against the pushing member 42. And working chamber 4
The supply oil pressure to 4 constitutes the urging means according to the present invention.

This embodiment is configured as described above.
At the stage when the compressor is stopped together with the engine, the spool valve body 53 is at the forward end and is kept closed by the pressure balance in the machine, and the spring force of the coil spring 45 acting unilaterally. As a result, the pushing member 42 advances and regulates the moving position of the sleeve 12, forcing the rotary swash plate 14 to have a capacity posture equal to or larger than the regulated capacity. When the drive shaft 6 is rotated following the start of the engine from this state, the compressor starts the compression work based on the inclination angle of the rotary swash plate 14 simultaneously with the activation of the gear pump 30 directly connected to the drive shaft 6. I do.
When the compression work is started in this manner, the outlet pressure of the evaporator E acting on the spool valve body 53 in a manner balanced with the crank chamber pressure is reduced, and the spool valve body 53 is retreated by the generated differential pressure. Is switched to the open state. Therefore,
Oil discharged from the gear pump 30 is supplied from the pressure guide passage 35 to the valve chamber 51.
The hydraulic pressure is supplied to the working chamber 44 via the hydraulic pressure, and the hydraulic pressure overcomes the opposing spring force of the coil spring 45 to retract (retract) the pushing member 42. That is, at this point, the sleeve 12
Is completely removed, and the rotation of the rotary swash plate 14 is controlled to a freely variable range by operating the control valve 20 according to the cooling load. When the cooling load is further reduced due to the vehicle environment and the state shifts to a state where cooling is unnecessary, the sleeve 12 and the rotary swash plate 14, which have been released from the restriction by the depression of the pushing member 42, control the operation of the control valve 20. On the basis of this, the displacement to the zero-capacity posture is allowed, and the compression work is necessarily stopped.

When the compressor is practically disabled, the internal pressure of the compressor is balanced as soon as the high-pressure refrigerant passes through the bleed passage 24, and the spool pressure is balanced by the balance between the crank chamber pressure and the evaporator outlet pressure. The valve body 53 is switched to the original closed state. Accordingly, the supply of oil to the working chamber 44 via the pressure guiding path 35 is shut off, and at the same time, the retained oil in the working chamber 44 flows out into the crank chamber 5 through the return oil orifice 46. Spring force urges the pushing member 42 to advance, forcing the rotary swash plate 14 to return to the regulated capacity position again via the abutting sleeve 12. Thus, when the compression work of the regulated capacity is resumed, the pushing member 42 is immediately immersed with the above-described reversal operation of the spool valve body 53 and the start of refueling to the working chamber 44. As long as it is maintained, the compressor will maintain zero or near zero capacity, minimizing excessive cooling and power consumption, while at the same time protecting the compressor by supplying lubricating oil through minimal compression work. I do. The oil discharged from the gear pump 30 is supplied to the relief valve 3 mounted on the drive shaft 6.
The oil is always supplied to the shaft sealing chamber via the oil hole 2 and the oil hole 33, and is used for lubrication of the shaft seal 34 which is particularly concerned.

[0019]

As described in detail above, the present invention realizes the ultra-small capacity operation from the regulated capacity to the zero capacity by the configuration described in the claims, so that the omission of the electromagnetic clutch is omitted. It is possible to contribute to the weight reduction of the compressor and the reduction of the engine load, and it is also possible to rationally prevent the frost of the evaporator due to the overcooling and the burning of the compressor caused by the shortage of the refrigerant (lubricating oil). .

[Brief description of the drawings]

FIG. 1 is a sectional view of a variable displacement compressor according to an embodiment of the present invention, showing a steady operation state in which a pushing member is immersed.

FIG. 2 is a cross-sectional view of the compressor, showing a state in which a pushing member has advanced.

FIG. 3 is a sectional view showing a conventional variable displacement compressor.

[Explanation of symbols]

1 is a cylinder block, 5 is a crankcase, 6 is a drive shaft,
9 is a bore, 10 is a piston, 12 is a sleeve, 14 is a rotary swash plate, 20 is a control valve, 30 is a gear pump, 35 is a pressure guiding path, 42 is a pressing member, 44 is a working chamber, 45 is a coil spring, 52 is a detection tube, 53 is a spool valve

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tomohiko Yokono 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (56) References JP-A-3-143725 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F04B 27/14

Claims (1)

(57) [Claims] A crankshaft; a drive shaft extending into the crankcase and rotatably supported; a rotor fixed to the drive shaft; and a sleeve fitted to the drive shaft. A rotary swash plate pivotally supported to be tiltable and supported by the rotor via a hinge mechanism; and a plurality of rotary swash plates linked to the rotary swash plate for linearly moving in the respective bores based on the rotational swing. A piston, a suction chamber for supplying a fluid into the bore, a discharge chamber from which the fluid compressed in the bore is discharged, and a control valve for adjusting a pressure in the crank chamber; A variable displacement compressor configured to adjust the pressure difference between the chamber pressure and the crank chamber pressure and to vary the intake volume of the fluid into the bore by changing the tilt angle of the rotary swash plate, wherein the variable displacement compressor is connected to the drive shaft. And a gear pump for pumping the enclosed oil inside the machine. An urging means that opposes pressure and spring force regulates the displacement of the rotary swash plate via the sleeve by means of urging means, and a pushing and retracting member which can move in and out, and supplies oil to the urging means in response to the outlet pressure of the evaporator. Valve means for selectively controlling the swash plate at the advanced position of the pushing member, and forcing the rotating swash plate to the zero-capacity posture at the retracted position. A variable displacement compressor characterized by the following.