JPH0693967A - Variable capacity type compressor - Google Patents

Abstract

PURPOSE:To eliminate an electromagnetic clutch by protecting a compressor and suppressing the occurrence of supercooling. CONSTITUTION:A variable volume type compressor comprises a gear pump 30 coupled to a drive shaft 6 and causing the forced feed of seal oil in a machine, a retractable press member 42 regulating displacement of a rotary swash plate 14 through a sleeve by an energizing means by means of which the oil pressure of the gear pump 30 is opposed to a spring force, and a valve means to selectively control feed oil to the energizing means in answer to the outlet pressure of a vaporizer E. The rotary swash plate 14 is forced into a regulation volume posture in the protrusion position of the press member 42. Since the rotary swash plate 14 is allowed to take a zero capacity posture in a retraction position, an electromagnetic clutch can be eliminated, the weight of a compressor is reduced, and an engine load is retrieved.

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 Japanese Patent Laid-Open No.
The one disclosed in Japanese Patent Publication No. 16177 is known. As shown in FIG. 3, the compressor has 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 for the rotor 54.
A rotary swash plate 56 supported through the rotary swash plate 56, and a swing plate 57 attached along the rotary swash plate 56 in a state in which rotation is restricted,
A plurality of pistons 59 that reciprocate in the bore 58 by the swing of the swing plate 57, a suction chamber 60 that supplies fluid into the bore 58, a discharge chamber 61 that discharges the compressed fluid, and a crank chamber 52. Is provided in a bleed passage 63 that connects the suction chamber 60 with the suction chamber 60, and mainly includes a valve means 62 that senses the pressure in the suction chamber 60 and adjusts the opening degree of the bleed passage 63. The hinge mechanism 55 for connecting the rotor 54 and the rotary swash plate 56 is provided with a long hole on the rotor 54 side, and the pin portion mounted on the rotary swash plate 56 side is inserted into the long hole. The rotary swash plate 56 is supported by the rotor 54 so that the rotary swash plate 56 can be tilted within the range of the length of the long hole.

According to this structure, the following effects can be obtained. That is, when the opening degree of the extraction passage 63 is adjusted by the operation of the valve means 62 according to the suction pressure and the crank chamber pressure is changed at any time 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 oscillating plate 57 change, which changes the piston stroke and the bore 5.
The volume of fluid taken up by 8 is controlled. That is, the suction pressure is controlled to be a preset value by such a variable volume mechanism.

[0004]

Now, according to the variable volume mechanism as described above, the valve means 6 is operated as the suction pressure is lowered.
2 operates so as to reduce the opening degree of the extraction passage 63 and controls to increase the crank chamber pressure so as to reduce the capacity of the compressor, but the valve means 62 causes the extraction passage to decrease due to a further decrease in heat load. Even when 63 is completely closed and the compressor capacity is further reduced due to the crank chamber pressure that is further increased accordingly, the lower limit is regulated to the preset minimum capacity. This is because effective compression work is not performed in zero or an extremely small capacity range close to zero, and capacity return control based on the differential pressure between the suction pressure and the crank chamber pressure is virtually impossible. In addition, in recent compressors that require the lubrication of each sliding part in the machine to the mixed oil particles in the refrigerant, even if seizure or deterioration of durability caused by insufficient refrigerant (lubrication), the lower limit of capacity control must be restricted. It can be pointed out as one of the causes.

Therefore, since the minimum capacity of the compressor is regulated in this way, the electromagnetic clutch is disconnected depending on the environment in which the vehicle air conditioner is used, such as in a cold region, for the purpose of protecting the compressor and preventing frost on the evaporator. It is necessary to stop the compressor via. In other words, the electromagnetic clutch connected to the compressor is widely put into practical use as an indispensable constituent element of the current vehicle air-conditioning system, but the electromagnetic clutch is not only affected by the shock at the start, but also the driving feeling. It is also a problem that cannot be overlooked that the efficiency of the alternator that supplies power is surprisingly low, and the load on the engine is increasing accordingly. In other words, if it is possible to omit the electromagnetic clutch, it will be easy to understand that it will not only contribute to the pursuit of fuel efficiency, but will also bring about an epoch-making result in weight reduction of the compressor.

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

[0007]

In order to solve the above 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 so as to be tiltable and supported by the rotor through a hinge mechanism; A plurality of pistons that directly move in each bore based on movement, a suction chamber that supplies fluid into the bore, a discharge chamber that discharges fluid compressed in the bore, and a pressure in the crank chamber. And a control valve for adjusting, which is configured to adjust the differential pressure between the suction chamber pressure and the crank chamber pressure by the control valve and change the inclination angle of the rotating swash plate to change the intake volume of the fluid into the bore. In the variable displacement type compressor, which is connected to the drive shaft, A gear pump for sending oil under pressure, a push-pull member capable of retracting and restraining the displacement of the rotary swash plate via the sleeve by a biasing means that opposes the oil pressure and spring force of the gear pump, and an evaporator. Valve means for selectively controlling the oil supply to the urging means in response to the outlet pressure of the urging means, forcing the rotating swash plate to have a restricted capacity posture at the advancing position of the pushing member, and at the retracted position thereof. The rotating swash plate has a new configuration that allows zero capacity posture.

[0008]

When the compressor is stopped together with the engine, the valve means maintains the closed state due to the pressure balance inside the machine, and it is unidirectionally pushed by the biasing means acting only by the spring force. The member advances and regulates the moving position of the sleeve, forcing the rotating swash plate to have a capacity posture that is greater than or equal to the regulation capacity. When the drive shaft is rotated following the start of the engine from this state, the compressor also starts the compression work based on the inclination angle of the rotary swash plate at the same time as the gear pump directly connected to the drive shaft is activated. When the compression work is started in this way, the outlet pressure of the evaporator, which has been acting on the valve means in a form that balances with the crank chamber pressure, is reduced, and the generated differential pressure switches the valve means to the open state. Therefore, the oil discharged from the gear pump is supplied to the urging means via the valve means, and this oil pressure overcomes the opposing spring force to immerse the pushing member, so that the control according to the cooling load is performed thereafter. By operating the valve, the rotary swash plate is controlled within a variable range. If the cooling load decreases to a state where cooling is unnecessary, the rotary swash plate together with the sleeve is displaced to the zero capacity posture without being obstructed by the pushing member that is immersed, and the compression work is inevitable. Be stopped.

When the compressor is practically disabled as described above, the internal pressure of the machine is soon balanced due to the discharge of the high-pressure refrigerant through the extraction 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 biasing means, which has been cut off the hydraulic pressure, causes the spring force to rise and urges the pushing member to advance, and the rotary swash plate is again returned to the restricted capacity posture via the sleeve. Force a return. Thus, when the compression work of the regulated capacity is resumed, the pushing member is immediately retracted with the above-described reversing operation of the valve means and the biasing means, so that the compressor is zero or as long as the cooling-free state is continued. It maintains an ultra-small capacity near zero, suppresses excessive cooling and power consumption, and at the same time protects the compressor by supplying lubricating oil through a minimum amount of compression work. The oil discharged from the gear pump is constantly sent to the shaft sealing chamber via a relief valve and an oil hole built in the drive shaft, and is used for lubrication of a particularly concerned shaft seal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying 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 a compressor, and a rear housing 3 is connected to a rear end thereof via a valve body 4. A crankshaft 5 formed by the cylinder block 1 and the front housing 2 accommodates a drive shaft 6 which is linked to an engine (not shown), and the drive shaft 6 is rotatably supported by bearings 7 and 8. . A plurality of bores 9 are formed in the cylinder block 1 so as to surround the drive shaft 6 and are arranged in parallel with each other. Pistons 10 are fitted into the bores 9, respectively.

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 rotatably and slidably fitted. . A counter spring 13 is interposed between the step portion of the drive shaft 6 and the sleeve 12 to bias the sleeve 12 in the rear direction, and the sleeve 12 is fitted onto the spherical bearing surface. A rotating swash plate 14 having an inner surface of a spherical zone is tiltably supported. The counter spring 13 shown in FIG.
In the most contracted state, the regulating surface 14a inclined to the lower rear surface of the rotary swash plate 14 abuts the inner end surface of the rotor body 11, and the maximum inclination angle of the rotary swash plate 14 is regulated. The piston 9 is moored to the disk surface formed on the outer peripheral portion of the rotary swash plate 14 through hemispherical shoes 5 and 5.

On the other hand, an arm 16 which constitutes a hinge mechanism is projected rearward at the outer peripheral edge of the rotor 11, and the tip of this arm 16 has a spindle 1 perpendicular to the axis.
7 is rotatably inserted. A guide pin 1 that penetrates the support shaft 17 in the radial direction with the arm 16 interposed therebetween.
Both guide pins 18 in which the base ends of 8 and 18 are fixed and extend
The front end portion of is slidably inserted into a joint portion 19 formed on the front surface side of the rotary swash plate 14.

Reference numeral 20 denotes a control valve which is built in the rear housing 3 and which adjusts the opening degree of the 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 enclosing a spring or a gas body having a predetermined pressure, and a valve body 20b connected to the bellows 20a. By expanding and contracting the bellows 20a against the suction chamber pressure, The valve seat 23a of the air supply passage 23 is controlled to be opened / closed via the valve body 20b. Reference numeral 24 is a bleed passage that always 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 (trochoidal type) 30 directly connected to the end of the drive shaft 6 is housed in the rear housing 3, and the intake port of the gear pump 30 is connected to the crank chamber 5 via an oil passage 31.
The enclosed oil inside is introduced. Further, the discharge port of the gear pump 30 has a rear housing 3 side and a valve plate 4 side.
And a discharge port on the rear housing 3 side is provided in the drive shaft 6 with a relief valve 32 and an oil hole 33.
To the shaft-sealing chamber provided with the shaft seal 34, while the discharge port on the valve plate 4 side will be described later via a pressure guiding passage 35 formed from the valve plate 4 to the cylinder block 1. It is tied to the valve means.

A stepped hole having a different diameter is bored in the rear axial center of the cylinder block 1, and a cylindrical stopper 41 is press-fitted into the rear large-diameter hole, and the stopper 41 is fitted into the stopper 41. 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 hollow pushing member 42 is slidably fitted in the large diameter hole through a sealing element, and similarly, the body portion is also arranged at the bottom of the large diameter hole. The small diameter hole is tightly fitted through the lip seal 43, and a working chamber 44 is formed between the lip seal 43 and the flange portion of the pushing member 42. 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, and the limit of its moving in and out is the engaging portion protruding from the lip seal 43 and the stopper 41. It is regulated by the interference with 41a. FIG. 2 shows the advancing state of the pushing member 42, and the front end of the pushing member 42 at the time of advancing advances the regulation capacity (5 to 1
It has been adjusted to force a 0% returnable lower limit capacity posture. Incidentally, 46 is the working chamber 44 and the crank chamber 5
It is a return oil orifice that communicates with.

The cylinder block 1 is provided with a bottomed elongated hole-shaped valve chamber 51 extending along the large diameter hole.
The bottom portion of the detection conduit 5 communicates with the crank chamber 5 through a small hole, and the mouth end of the detection conduit 5 extends through the valve plate 4 and the rear housing 3.
The valve chamber 51 is connected to the outlet of the evaporator E by 2 and a part of the valve chamber 51 is also communicated with the working chamber 44 through a through hole. A spool valve body 53, whose both ends are supported by balance springs, is built in the valve chamber 51, and in a state where the crank chamber pressure guided to the valve chamber 51 and the evaporator outlet pressure are balanced, the spool valve body 53 is provided. Is the above pressure guiding path 3
5 and the working chamber 44 are cut off from each other, and on the other hand, when the pressure difference between the crank chamber pressure and the crank chamber pressure is generated due to the decrease in the evaporator outlet pressure, the spool valve element 53 causes the pressure guiding path 35 and the working chamber Operates to allow communication with. In this way, the spool valve body 53 that selectively controls the oil supply to the working chamber 44 constitutes the valve means referred to in the present invention, and the spring force of the coil spring 45 that acts on the pushing member 42 in opposition. And working chamber 4
The oil pressure supplied to No. 4 constitutes the urging means in the present invention.

This embodiment is constructed as described above,
At the stage when the compressor is stopped together with the engine, the spool valve element 53 is in the forward end and is kept closed due to the pressure balance inside the machine, and the spring force of the coil spring 45 acting unilaterally is maintained. 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 volume posture that is equal to or larger than the regulation volume. When the drive shaft 6 is rotated following the start of the engine from this state, the compressor also starts compression work based on the inclination angle of the rotary swash plate 14 at the same time as the gear pump 30 directly connected to the drive shaft 6 is activated. To do.
When the compression work is started in this way, the outlet pressure of the evaporator E that has been acting on the spool valve body 53 in a form that balances with the crank chamber pressure is reduced, and the spool valve body 53 moves backward due to the generated differential pressure. Switch to open state. Therefore,
The oil discharged from the gear pump 30 passes from the pressure guiding passage 35 to the valve chamber 51.
Is supplied to the working chamber 44 via this, and this hydraulic pressure overcomes the spring force of the coil spring 45 which opposes, and the pushing member 42 is sunk (stored). That is, at this point, the sleeve 12
Since the movement restriction to the small capacity side has been completely removed, the rotary swash plate 14 is controlled in a freely variable range by the operation of the control valve 20 according to the cooling load. When the cooling load further decreases due to the vehicle environment and the cooling is not required, the sleeve 12 and the rotary swash plate 14, which are released from the regulation due to the depression of the pushing member 42, control the operation of the control valve 20. Based on this, the displacement to the zero volume posture is allowed, and the compression work is inevitably stopped.

When the compressor is practically disabled in this way, the internal pressure of the compressor is soon balanced due to the discharge of the high-pressure refrigerant through the extraction passage 24, and the spool 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. Therefore, the oil supply to the working chamber 44 via the pressure guiding path 35 is cut off, and at the same time, the accumulated oil in the working chamber 44 flows out into the crank chamber 5 via the return oil orifice 46. The spring force urges the pushing member 42 to advance, and forces the rotating swash plate 14 to return to the restricted volume posture again via the abutting sleeve 12. When the compression work of the regulated capacity is resumed in this way, the pushing member 42 is immediately retracted with the reversing operation of the spool valve body 53 and the start of refueling to the working chamber 44, so that the state of cooling non-1 is As long as it is continued, the compressor keeps an ultra-small capacity state at or near zero to suppress excessive cooling and power consumption, and at the same time protect the compressor by supplying lubricating oil through a minimum amount of compression work. To do. The oil discharged from the gear pump 30 is supplied to the relief valve 3 installed in the drive shaft 6.
2 is constantly fed to the shaft-sealing chamber via the oil hole 33 and the oil hole 33, and is used for lubrication of a particularly concerned shaft seal 34.

[0019]

As described above in detail, the present invention realizes the ultra-small capacity operation from the regulated capacity to the zero capacity by the structure described in the claims, so that the electromagnetic clutch can be omitted. As a result, the compressor can be made lighter and the engine load can be reduced, and it is possible to rationally prevent the compressor from burning due to frost on the evaporator due to overcooling and a shortage of refrigerant (lubricating oil). .

[Brief description of 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 retracted.

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

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

[Explanation of symbols]

1 is a cylinder block, 5 is a crank chamber, 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 guide path, 42 is a pushing member, 44 is a working chamber, 45 is a coil spring, 52 is a detection tube, 53 is a spool valve body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomohiko Yokono 2-chome, Toyota-cho, Kariya city, Aichi Stock company Toyota Industries Corp.

Claims (1)

[Claims] 1. A crank chamber, a drive shaft extending in the crank chamber and rotatably supported, a rotor fixed to the drive shaft, and a sleeve fitted to the drive shaft. A rotary swash plate which is pivotally supported in a tiltable manner and is supported by the rotor through a hinge mechanism, and a plurality of rotary swash plates which are linked to the rotary swash plate and linearly move in the respective bores based on the rotation and swing thereof. The piston includes a suction chamber that supplies fluid into the bore, a discharge chamber that discharges the fluid compressed in the bore, and a control valve that adjusts the pressure in the crank chamber. A variable displacement compressor configured to adjust the differential pressure between the chamber pressure and the crank chamber pressure and change the inclination angle of the rotary swash plate to change the intake volume of the fluid into the bore. And a gear pump that pumps the enclosed oil in the machine by pressure. A biasing means that opposes pressure and spring force controls the displacement of the rotating swash plate through the sleeve by means of a retractable push-pull member, and oil is supplied to the biasing means in response to the outlet pressure of the evaporator. And a valve means for selectively controlling, and is configured to force the rotary swash plate to have a restricted volume posture at the advancing position of the pushing member and to allow the rotary swash plate to have a zero volume posture at the retracted position. Variable capacity compressor characterized by.