JP3301566B2 - Reciprocating 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 compressor suitable for use in vehicle air conditioning, and more particularly to a multi-cylinder reciprocating compressor having a single-headed piston.

[0002]

2. Description of the Related Art Conventionally, as a compressor of this type, a rotating swash plate is moored to a single-headed piston via a shoe, or a swinging plate whose rotation is restricted is connected to a single-headed piston via a connecting rod. A known type of compressor is known. In these fixed displacement compressors, an intermittent operation is performed in which the clutch is turned off to prevent frost of the evaporator when the heat load is reduced, and the clutch is turned on again when the heat load is restored.

[0003]

However, when the compressor is started, the durability of components including the clutch is reduced due to a sudden increase in torque, and the driving feeling is extremely impaired due to the deceleration. Further, in the idling state of the engine, there is a possibility that the idling rotation may be destabilized due to the load fluctuation, and the engine may be stalled.

An object of the present invention is to suppress radical torque fluctuation at the time of starting a compressor, to reduce the load on the engine and to improve the driving operability.

[0005]

According to the present invention, there is provided a cylinder block having a plurality of bores, a front housing for forming a crank chamber and closing one end of the cylinder block, and an inner region. A rear housing for forming a suction chamber in the outer region and closing the other end of the cylinder block via a valve plate; and a swash plate element fixed to a drive shaft extending into the crank chamber. A reciprocating compressor including a single-headed piston that moves directly in the bore in cooperation with the swash plate element, the reciprocating compressor having at least one bore corresponding to at least one bore mounted on the valve plate. With
The main discharge valve corresponding to each bore of the remainder is combined with a retainer and comprises an unloading mechanism which is disengaging capable configured for the valve plate by opposing the urging force of the I field between the discharge pressure, the discharge A new configuration is adopted in which a check valve that prevents backflow of high-pressure refrigerant is provided at the discharge port that opens to the chamber.

[0006]

During the normal operation of the compressor, the discharge pressure causes the main discharge valve of the unload mechanism to maintain a load state close to the valve plate, and participates in the regular compression work together with the sub discharge valve. And when the compressor is stopped, the check valve prevents the refrigerant from flowing back from the high pressure circuit, while the remaining refrigerant in the discharge chamber leaks through the minute gap of the unload mechanism to the low pressure area, As the pressure inside the machine approaches an equilibrium state, the main discharge valve is separated from the valve plate by the biasing force of the spring and is displaced to the unload state. Thereafter, when the compressor is restarted, initially only the bore corresponding to the sub-discharge valve starts the compression work, gradually increasing the discharge pressure, and the urging force of the spring succumbs to the discharge pressure, so that the main discharge valve Is gradually displaced to the load state and returns to full capacity operation.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be specifically described below with reference to the drawings. In FIG. 1, a front housing 2 is connected to a front end of a cylinder block 1 which forms a part of an outer shell of the compressor, and a suction chamber 5 is formed in an outer area and a discharge chamber 6 is formed in an inner area at the rear end. The rear housing 3 is connected via a valve plate 4. A drive shaft 8 connected to a power source is inserted through a crank chamber 7 formed in the front housing 2, and the drive shaft 8 is connected to the cylinder block 1 and the front housing 2 by radial bearings 20 and 2, respectively.
It is rotatably supported via 1. A rotary swash plate 9 is fixed on a drive shaft 8 in the crank chamber 7.
A rocking plate 10 is supported on the rear surface side so as to be relatively rotatable, and a guide portion 10 a provided on an outer edge portion is engaged with a through bolt 11 to restrict rotation and penetrate the cylinder block 1. The single-headed piston 13 in the bore 12 and the swing plate 10 are connected by a connecting rod 14. Therefore, the rotational motion of the drive shaft 8 is converted into the forward and backward swing of the swing plate 10 via the rotary swash plate 9, and the single-head piston 1
3 reciprocates in the bore 12, so that the refrigerant gas sucked into the bore 12 from the suction chamber 5 through the suction valve 15 is compressed and discharged to the discharge chamber 6 through discharge valves 16a and 16b described later. Discharged.

A boss 1a projecting into the crank chamber 7 is formed in the axial center of the cylinder block 1, and the radial bearing 20 is press-fitted into a central shaft hole formed in the boss 1a. The rear end of the drive shaft 8 supported by the radial bearing 20 is supported by a thrust trace 22 and a disc spring 23 housed in a center shaft hole, and the urging force of the disc spring 23 is It is received by a thrust bearing 24 interposed between the rotating housing 9 fixed to the drive shaft 8 and the front housing 2. Reference numeral 17 denotes a bleed passage that connects the crank chamber 7 and the suction chamber 5.

Next, the most characteristic unloading mechanism of the present invention will be described. In FIGS. 1 to 3, a bottomed circular chamber 30 is bored through the valve plate 4 at the center of the cylinder block 1, and a plunger 31 inserted into the chamber 30 has four bores 12 (specifically, Specifically, the main discharge valve 16a having a lead portion corresponding to each discharge hole 18) is
It is connected with the retainer 19a. The plunger 31 is connected to the discharge pressure and the spring 3 provided in the chamber 30.
2 is slidable against the urging force of the main discharge valve 16a.
Are configured to closely adhere to the valve plate 4 . in this way,
Spring 32, plunger 31, plunge in chamber 30
Main discharge valve 16a fixed to sleeve 31 and retainer 19a, etc.
Constitutes an unloading mechanism. Your name, 33
Is a detent pin which is press-fitted into the cylinder block 1 and whose protruding portion interferes with the main discharge valve 16a and the retainer 19a to prevent its rotation. Reference numeral 34 denotes a passage connecting the bottom of the chamber 30 and the crank chamber 7. Stomata.

As is apparent from FIG. 3, the auxiliary discharge valve 16b
The retainer 19b is directly mounted on the valve plate 4, and only one of the remaining bores 12 corresponding to the auxiliary discharge valve 16b via the discharge hole 18 cannot be unloaded. Further, a check valve 35 for preventing a backflow of the high-pressure refrigerant is provided at a discharge port 6a opened to the discharge chamber 6. This embodiment is configured as described above, and the discharge pressure is applied to the plunger 31 during the normal operation of the compressor in the advancing direction (left direction in the drawing) and in the retreating direction (right direction in the drawing). The crank chamber pressure and the urging force of the spring 32 are acting toward
In this state, the discharge pressure controls the opposing pressure to advance the plunger 31, and the main discharge valve 16a is maintained in a loaded state in which the main discharge valve 16a is tightly fitted to the valve plate 4 (FIG. 1). That is, the main discharge valve 1
6a participates in the regular compression work together with the fixed auxiliary discharge valve 16b.

When the compressor is stopped due to a decrease in heat load or the like, the check valve 35 prevents the backflow of the refrigerant from the high-pressure circuit, while the remaining refrigerant in the discharge chamber 6 has a small fitting of the plunger 31. The play gap, the valve plate 4 and the main discharge valve 16a
Through the contact gap between the crank chamber 7 and the vent hole 34.
As the pressure inside the machine approaches an equilibrium state, the plunger 31 is gradually retracted by the urging force of the spring 32. That is, the main discharge valve 16a is separated from the valve plate 4 together with the retainer 19a, and is displaced to an unload state where the main discharge valve 16a is stopped by the collision wall in the discharge chamber 6 (FIG. 2).

Thereafter, when the compressor is restarted due to an increase in heat load or the like, the unloadable auxiliary discharge valve 16b and the corresponding bore 12 immediately start the compression work, but the remaining bore associated with the main discharge valve 16a. Since all 12 are in the disabled state, the starting torque of the compressor is extremely small, and the engine load is satisfactorily reduced. When the discharge pressure is gradually increased by the single bore 12 that continues the compression work, the urging force of the spring 32 yields to the discharge pressure, the plunger 31 advances, and the main discharge valve 16a is opened. Board 4
The compressor shifts to normal full-capacity operation.

In the above embodiment, the auxiliary discharge valve 16b
However, only one bore 12 cannot be unloaded, but individual or common sub-discharge valves 16b are provided in a plurality of bores 12 selected according to the number of cylinders to shift to full capacity operation at startup. May be configured to hasten
In the embodiment, when the compressor is stopped, the discharge chamber 6 is stopped.
Remaining refrigerant in the sneaks through the minute gap of the unload mechanism,
The mode in which the internal pressure is balanced by leaking to the low pressure region has been described. However, the discharge chamber 6 and the suction chamber 5 are communicated by small holes within a range where the refrigeration capacity is allowed to decrease, and the internal pressure is balanced. It can be configured to be performed more quickly.

[0014]

As described in detail above, in the compressor according to the present invention, when the compressor is started, a specific bore corresponding to the sub-discharge valve performs compression work, and the remaining bore corresponding to the main discharge valve. Are completely disabled, the startup torque is extremely small, and fatigue deterioration of the compressor and clutch due to the starting impact can be effectively prevented.

Further, since the engine load accompanying the start of the compressor is inevitably reduced, good operability can be maintained without impairing the driving feeling.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a normal operation state of a compressor according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state before starting the compressor.

FIG. 3 is a sectional view taken along the line AA of FIG. 1, showing a form of a discharge valve of the compressor.

[Explanation of symbols]

1 is a cylinder block, 2 is a front housing, 3 is a rear housing, 4 is a valve plate, 5 is a suction chamber, 6 is a discharge chamber,
6a is a discharge port, 7 is a crank chamber, 8 is a drive shaft, 12 is a bore, 13 is a single-head piston, 16a is a main discharge valve, 16b is a sub discharge valve, 18 is a discharge hole, 19a is a retainer, 30 is a chamber, 31 is a plunger, 32 is a spring, 34 is a vent, 35 is a check valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F04B 27/14 F04B 39/10

Claims (1)

(57) [Claims] 1. A cylinder block having a plurality of bores arranged side by side, a front housing forming a crank chamber and closing one end of the cylinder block, a discharge chamber in an inner area, and a suction chamber in an outer area. A rear housing for closing the other end of the cylinder block via a valve plate, a swash plate element fixed to a drive shaft extending into the crank chamber, and A reciprocating compressor having a single-headed piston that directly moves the main discharge valve having at least one bore and a corresponding sub-discharge valve mounted on the valve plate, and a main discharge valve corresponding to each of the remaining bores. coupled with the retainer, and includes an unload mechanism that is disengaging capable configured for the valve plate by opposing the urging force of the I bus and the discharge pressure, the high pressure refrigerant to the discharge port opened to the discharge chamber Prevent backflow Reciprocating compressor formed by arranging a check valve.