JPS634027B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compressor whose capacity can be changed according to operating conditions, and particularly to a variable capacity compressor suitable for vehicle air conditioning.

In general, cabin cooling is performed in two ways: a cooling mode that lowers the indoor temperature, and a heat retention mode that keeps the interior at a comfortable low temperature. Therefore, large cooling capacity is not required. Conventionally, in order to meet the demand for rapid cooling, a large-capacity compressor was often mounted on the tower within the range allowed by the engine capacity. Therefore, during normal driving in thermal mode, the compression function power was excessive for the cooling load, and the compression The machine will operate at a low cooling load. As a result, the compressor is operated with low volumetric efficiency, and the clutch interposed between the engine and the compressor is turned on and off more frequently, causing severe wear and tear on the clutch.
The starting torque generated with each repeated ON/OFF operation is large and has a negative impact on driving feeling. Furthermore, the liquid compression that sometimes occurs during startup is
The discharge amount per revolution at startup is also large, which is a harsh condition for compressors that do not have sufficient discharge chamber volume, which can significantly impede the durability of the compressor and, in rare cases, cause large noise. It had drawbacks. Additionally, some luxury cars use an EPR (constant evaporative pressure) cycle in which the compressor is kept running all the time, and if it cools down too much, it is heated to the optimum temperature and then blown out. , this is becoming extremely wasteful.

An object of the present invention is to eliminate the above-mentioned conventional problems and to provide a variable capacity compressor that can switch the compressor capacity in stages according to the cooling load and that can reliably switch the compressor capacity. It is about providing.

Embodiments of the present invention will be described in detail below with reference to the drawings. First, let's talk about the first embodiment for a swash plate compressor with 5 cylinders on one side, that is, 10 cylinders.
This will be explained with reference to FIG. In the figure, the opposite ends of cylinder blocks 1 and 2 are valve plates 3,
It is closed by both front and rear housings 5, 6 with a housing 4 in between, and these are assembled with an appropriate number of bolts 7. A swash plate chamber 8 is formed at the joint portion of the cylinder blocks 1 and 2, and the swash plate chamber 8 is inclined with respect to the drive shaft 9 passing through the shaft holes 1a and 2a formed through the centers of the cylinder blocks 1 and 2. A fixed swash plate 10 is housed therein.
Radial bearings 13 and 14 that support the drive shaft 9 are press-fitted into the boss portions 11 and 12 of the cylinder blocks 1 and 2 through which the drive shaft 9 passes, and between the boss portions 11 and 12 and the swash plate 10, Thrust bearings 64 and 65 are interposed. Five pairs of cylinder bores 15 are bored in the cylinder blocks 1 and 2 in parallel with the drive shaft 9 and at radial positions centered on the drive shaft 9, and the pistons 16 fitted in these cylinder bores 15 have balls 17 and shafts. 1
The piston 1 is moored to the swash plate 10 via a bearing device consisting of 8, and the rotational force of the swash plate 10 causes the piston 1 to
6 is capable of reciprocating within the cylinder bore 15. Discharge chambers 19, 20 are formed in the center of each of the front and rear housings 5, 6, and substantially annular suction chambers 21, 22 are formed on the outer periphery so as to surround the discharge chambers 19, 20. In particular, the discharge chamber 19 on the front side is formed in an annular shape, and the discharge chamber 20 on the rear side is formed in a circular shape. Suction chamber 21,
22 communicates with a swash plate chamber 8 through suction passages 23 and 24 which also serve as through holes for the bolts 7, and the swash plate chamber 8 communicates with a suction flange 25 mounted near the mating surfaces of the cylinder blocks 1 and 2. has been done. Further, at one location between the bores in the cylinder blocks 1 and 2, a circular discharge passage 26 and 2 with a bottom extends from the contact surface with the valve plates 3 and 4 to the mating surface.
7 is bored, and one end of the discharge passages 26, 27 communicates with a discharge flange 28 mounted near the mating surfaces of the cylinder blocks 1, 2 via communication passages 29, 30, respectively, and the other end is valve plate 3,
The discharge chambers 19 and 20 are communicated with each other through communication holes 31 and 32 provided through the discharge chambers 4 . However, discharge chamber 1
The communicating portions 9 and 20 with the discharge passages 26 and 27 are appropriately bulged toward the outer periphery. Also, a communication passage 30 connecting the rear side discharge passage 27 and the discharge flange 28 is provided.
includes a closing valve 33 for opening and closing the communication passage 30.
is provided, and when the inside of the rear side discharge chamber 20 is in a low pressure state, the communication passage 30 is closed, and when the pressure is high, the communication passage 30 is opened. Note that the closing valve 33 may be configured to be always biased in the opening direction by a spring.

Suction ports 34, 35 and discharge ports 36, 37 are provided through the valve plates 3, 4, through which the cylinder bore 15 communicates with the suction chambers 21, 22 and discharge chambers 19, 20, respectively. Suction valves 38, 39 and discharge valves 40, 41 are provided at the suction ports 34, 35 and the discharge ports 36, 37, respectively. The amount of deformation of the discharge valves 40 and 41 is restricted by the valve holders 42 and 43, and the front side is fixed to the valve plate 3 together with the valve holder 42, but the rear side is fixed to the valve plate 3 together with the valve holder 42. Together with the valve holder 43, it can be moved between a normal closed position and an open position where the discharge port 37 is opened. That is, the rear valve holder 43 has the same shape as the discharge valve 41, that is, it is formed of an annular base 43a and a lead portion 43b extending to face each discharge port 37, and the discharge valve 41 and valve holder 43 are overlapped with each other. The presser foot 43 and a cylindrical spool 44 concentrically abutting the back surface of the valve presser 43 are integrated by a bolt 45, and the spool 44 is partitioned into the center of the rear housing 6 by a partition wall 6a. It is fitted in a circular first working chamber 46 so as to be slidable in the axial direction. Note that the three members integrated by the bolts 45 are prevented from rotating by a positioning pin 47 implanted in the partition wall 6a of the rear housing 6. Also,
The shaft hole 2a formed in the center of the rear cylinder block 2 is set so that the rear end of the drive shaft 9 enters the shaft hole to an appropriate depth, thereby forming the central part of the discharge chamber 20. A communicating circular space 48 is formed, and a cylindrical spring receiver 49 with a smaller diameter is fitted into the circular space 48 and is held by the valve plate 4. A spring 50 is housed therein, which biases the discharge valve 41 to keep it floating in the open position at all times. In addition, an appropriate number of small holes 49a are provided on the circumferential surface and bottom surface of the spring receiver 49 to communicate the cylindrical hole with the circular space 48.
A communication groove 51 is formed in the wall between the bore holes in the rear cylinder block 2 at the end surface in contact with the valve plate 4 to communicate the circular space 48 and the suction passage 24. , small hole 49
When the discharge valve 41 is held in the open position by the communication passage 52 consisting of the communication groove 51 and the communication groove 51, the discharge chamber 20 is communicated with the suction passage 24, but the discharge valve 41 is displaced to the normal closed position. This breaks that communication. Although the figure shows one communication groove 51, there may be a plurality of communication grooves 51, and it may be formed on the valve plate 4 instead of on the cylinder block 2, but in any case, it is better than the others. It is desirable that the refrigerant flow path system be connected to the suction passage 24 located far from the suction flange 25, where the pressure tends to be low.

Further, a cover 54 having a circular second working chamber 53 concentric with the first working chamber 46 on the opposite end side is fixed to the rear surface of the rear housing 6 with bolts 55. The center of the working chamber 53 communicates with the first working chamber 46 through a first pressure guiding hole 56, and the outer peripheral side communicates with the discharge chamber 20 through a plurality of relief holes 57. An annular check valve 58 for opening and closing the relief hole 57 is incorporated in the second working chamber 53, and the check valve 58 is formed in the second working chamber 53 when the relief hole 57 is opened. It is received by an annular stepped seating surface 53a, and the surface area of this stepped seating surface 53a is set smaller than the opposing surface area of the check valve 58. In addition,
The check valve 58 may be configured to always be biased in the closing direction by a spring, but the spring force in this case must be set smaller than the pressure inside the discharge chamber 20 during normal operation. A second pressure guiding hole 59 passing through the second working chamber 53 is provided in the center of the cover 54, and this second pressure guiding hole 59 is connected to the discharge flange 28 by a high pressure pipe 61 including a first electromagnetic valve 60. It is also connected to the suction flange 25 by a low pressure pipe 63 that includes a second solenoid valve 62 . The opening/closing control of the first solenoid valve 60 and the second solenoid valve 62 is performed by a pressure switch (not shown) provided in the suction system, for example, which responds to the temperature inside the vehicle to be cooled. It is also possible to replace the first and second solenoid valves 60 and 62 with a single switching valve, and the high pressure pipe 61 and the like can be installed inside the compressor components if there is space for them. Good too.

This embodiment is configured as described above,
The effect will be explained below. When stopped, the rear discharge valve 41 is moved by the spring 50 as shown in FIG.
The closing valve 33 closes the communication passage 30, the first solenoid valve 60 is opened, the second solenoid valve 62 is closed, and the check valve 58 is opened. The hole 57 is held in an open position (sometimes it may be in a closed position).

When the compressor is driven in such a state, the front side starts operating normally and immediately enters compression, but on the rear side, since the discharge port 37 is open, each cylinder bore 15 and the discharge room 20
The gas only flows freely (reciprocating flow) between the discharge chamber 20 and the suction passage 24.
Since these are short-circuited by the communication passage 52, the compressor does not substantially perform a compression action and operates idly. Therefore, since operation is started with 50% capacity at startup, the start-up torque is small and the degree of liquid compression is halved. In addition, the closing valve 3
3 is always biased in the opening direction by a spring, the front side discharge chamber 1 is opened at startup.
9 also communicates with the suction passage 24 and the entire space of the compressor is short-circuited. Immediately after startup, operation is performed at 0% compression capacity, and after that, the closing valve 33 is closed due to the large discharge flow rate of the communication passage 30, so that the front side pressure is As a result, the front side enters normal operation with a slight delay after the compressor is started, and the compressor is operated at 50% capacity. Therefore, when such a configuration is adopted, it is more advantageous to further reduce the start-up torque and prevent liquid compression than when no spring is used.

During normal operation on the front side, the discharge pressure acts on the second working chamber 53 from the high pressure pipe 61 through the second pressure guiding hole 59, and as the pressure in the chamber 53 increases (through the relief hole 57, the discharge pressure When the check valve 58 is pressed against the back surface of the rear housing 6 (by the gas flow flowing to the spool 20) and the discharge pressure acts on the back surface of the spool 44 in the first working chamber 46 through the first pressure guiding hole 56 (at this time The first solenoid valve 60 remains open and the second solenoid valve 62 remains closed.
0 to the normal closing position, in other words, it is pressed against the valve plate 4 and closes each discharge port 37 and communication passage 52 of the cylinder bore 15, so a normal compression action is started on the rear side as well, and the closing valve is pressed against the valve plate 4. 33 is pushed up by the rear discharge pressure to open the communication passage 30, thus operating the compressor at 100% capacity (see Figure 2).

Next, to explain steady operation, when the cooling load is large, that is, when the cooling load is large, the rear side is also operated normally and operates at 100% capacity as described above. In this case, there is no problem in the operation of the compressor whether the check valve 58 is in the open or closed position, but in reality the pressure on the discharge chamber 20 side is slightly higher than the pressure on the discharge flange 28 side. This is thought to be liberating from the high cost. However, when the cooling load becomes small, that is, when the interior of the vehicle is cooled and the suction pressure decreases accordingly, the pressure switch is turned on, the first solenoid valve 60 is closed, and the second solenoid valve 62 is opened. Therefore, the inside of the second working chamber 53 becomes suction pressure, and low suction pressure acts on the back of the spool 44 inside the working chamber 46. On the other hand, as the pressure inside the second working chamber 53 decreases, a back check occurs. valve 58 is opened (or opened as described above);
The gas in the discharge chamber 20 flows out from the relief hole 57 to the second working chamber 53, and the pressure in the discharge chamber 20 decreases, and the closing valve 33 closes the communication passage 30 accordingly.
Therefore, not only the inside of the first working chamber 46 but also the discharge chamber 2
As a result of the suction pressure acting on the back surface of the spool 44 and the back surface of the discharge valve 41, the rear discharge valve 41 is lifted off the valve plate 4 by the spring 50, and the discharge port 37 is lifted up from the valve plate 4 by the spring 50. When the engine is opened, the rear side is stopped and the compressor is switched to 50% operation as in the case of startup described above.

Therefore, when the compressor is operating at 100%, the pressure in the suction passage 24 is slightly lower than that in the shaft hole 2a due to the rapid gas flow, and therefore the pressure in the suction flange 24 is slightly lower than that in the shaft hole 2a.
A part of the suction gas that has flowed into the swash plate chamber 8 from the rear thrust bearing 65 passes through the shaft hole 2a, the radial bearing 14, the circular space 48, and the communication groove 51 to the suction passage 24. This lubricates both the rear radial and thrust bearings 14, 65. In addition, at 50% operation, the rear discharge valve 41 is in the open position and the pressure inside the discharge chamber 20 is slightly higher than that of each space in the suction system. Hole 2a, swash plate chamber 8
This generates a gas flow to lubricate both the rear radial and thrust bearings 14, 65. Note that during this 50% operation, part of the gas flows out from the discharge chamber 20 to the second working chamber 53, but when the check valve 58 is configured to close with a spring as described above, this gas flow is blocked. The lubrication effect can also be enhanced.

Next, a second embodiment in which the present invention is applied to a crank type compressor will be described with reference to FIGS. 6 to 9. This embodiment shows a reciprocating two-cylinder cylinder, in which a housing 68 (or top head) is attached to the upper end of a cylinder block 67 (or crank case) having a cylinder bore 66 via a valve plate 69, and a piston 70 is moved up and down within the cylinder bore 66 by rotation of the crankshaft 71. The housing 68 has front and rear discharge chambers 72, 73 and both discharge chambers 72, 73.
Each discharge chamber 72, 73 is defined by a suction chamber 74 arranged to surround the valve plate 69.
are in communication with the cylinder bore 66 through an inlet 77, respectively. The front side discharge valve 78 is integrated with a spool 82 that is slidably fitted into a circular first working chamber 81 formed by a valve holder 79 and a partition wall 80, and a bolt 83. The discharge valve 78 is biased by a spring 85 housed in a bottomed circular space 84 formed in the valve plate 69 so as to always maintain the discharge port 75 in the open position. Further, on the front side upper surface of the housing 68, there is a circular second working chamber which communicates with the first working chamber 81 through the first pressure guiding hole 86 and with the front side discharge chamber 72 through the relief hole 87. A cover 89 with 88 is fixed with bolts 90,
The opening and closing of the relief hole 87 is controlled by a check valve 91 provided in the second working chamber 88, and the first solenoid valve 93 of the high pressure pipe 92 and the low pressure Based on the opening/closing control of the pipe 94 with the second electromagnetic valve 95, the spool 82 passes through the second pressure guiding hole 106.
The position of the discharge valve 78 is switched by applying discharge pressure or suction pressure to the back surface of the discharge valve 78 . The valve plate 69 has the circular space 84 and the suction chamber 7.
A communication passage 96 communicating with 4 is provided through the
When the discharge valve 78 is floating in the open position, the discharge chamber 72 is short-circuited to the suction chamber 74. Further, the rear discharge valve 97 is fixed in a closed position together with a valve holder 98.

On the other hand, the cylinder block 67 has an auxiliary discharge chamber 99.
The sub-discharge chamber 99 communicates with the front and rear discharge chambers 72 and 73 through the communication holes 101 and 102, and the sub-suction chamber 100 communicates with the intake chamber through the communication hole 103. It communicates with the chamber 74. A closing valve 104 that closes the communication hole 101 of the front side discharge chamber 72 is attached to the sub-discharge chamber 99 side with a bolt 105, and the closing valve 104 closes the communication hole 101 of the discharge chamber 72 on the front side when the front side is operated normally. It is released by the discharge pressure of .

The second embodiment is configured as described above,
Therefore, as in the embodiment described above, when the compressor is started, normal operation on the front side is performed later than on the rear side, and the compressor operates at 50% (the state shown in Fig. 6) and 100% operation (the state shown in Fig. 7). ), and during steady operation, the operation is switched between 50% operation and 100% operation depending on the size of the cooling load.
When switching from operation to 50% operation, the operating pressure not only on the spool 82 but also on the discharge valve 78 through the relief hole 87 can be actively reduced from the discharge pressure to the suction pressure, as in the previous embodiment. It will definitely be done. Further, according to this embodiment, since the check valve 91 always returns to the closed position due to its own weight when the compressor is stopped, gas does not flow out from the discharge chamber 72 through the relief hole 87 when the compressor is started. Prevented and no waste.

In addition, in both the first and second embodiments, 50
% operation, that is, when the discharge valves 41, 78 float to the open position, in addition to freeing the gas flow between the cylinder bores 15, 66 and the discharge chambers 20, 72, the discharge chambers 20, 72 are placed in the suction system space. However, the communication passage between the discharge chambers 20 and 72 and the suction system space is connected to the discharge chambers 20 and 72 during 50% operation.
Although this is effective in alleviating pressure fluctuations in the interior of 72 or preventing high pressure, it can be omitted if such a phenomenon does not occur.

As described in detail above, the present invention is capable of displacing some of the discharge valves for the discharge port connecting the cylinder bore, which is the compression chamber, and the discharge chamber in a compressor, between an open position and a normal closed position. Therefore, according to the present invention, the capacity of the compressor can be changed in stages according to the cooling load, resulting in efficient operation with less waste, and the ability to turn the clutch ON and OFF during low-load operation. This reduces the frequency of this, which helps extend its life, and also reduces startup torque and prevents liquid compression during startup.

Furthermore, in the present invention, the discharge valve is opened and closed by selectively applying discharge pressure or suction pressure to the back surface of the spool that is integrated with the discharge valve, which is always biased in the opening direction by a spring. ,
In this case, especially in the present invention, when the working pressure on the spool is switched from the discharge pressure to the suction pressure, the suction pressure is simultaneously applied to the discharge chamber, so that even if the discharge pressure remains applied to the discharge valve, This solves the problem of the discharge valve not operating under certain conditions, and ensures that the opening operation of the discharge valve, that is, the switching of the compression function, is performed reliably.

Furthermore, in the present invention, when the acting pressure on the back of the spool is switched to the discharge pressure, the discharge pressure is applied to the back of the check valve of the relief hole connecting the discharge chamber and the second working chamber, thereby causing gas to flow out from the discharge chamber. Since the seal can be sealed, no special sealing structure is required, which is advantageous in simplifying the structure.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIGS. 1 and 2 are longitudinal cross-sectional views showing the swash plate compressor of the first embodiment, FIG. 3 is a cross-sectional view taken along the line -- in FIG. 1, and FIG. A partial longitudinal sectional view showing the gas flow part of the discharge system,
FIG. 5 is a sectional view taken along the line -- in FIG. 1, FIGS. 6 and 7 are longitudinal sectional views showing the crank type compressor of the second embodiment, FIG. 8 is a sectional view taken along the line -- in FIG. 8. 1, 2, 67... cylinder block, 5, 6,
68... Housing, 15, 64... Cylinder bore, 19, 20, 72, 73... Discharge chamber, 21,
22, 74... Suction chamber, 23, 24... Suction passage, 25... Suction flange, 26, 27... Discharge passage, 28... Discharge flange, 33, 104...
Closing valve, 36, 37, 75, 76...Discharge port, 4
0,41,78,97...discharge valve, 44,82...
... Spool, 46, 81 ... First working chamber, 50,
85... Spring, 53, 88... Second working chamber, 56, 86... First pressure guiding hole, 57, 87...
Relief hole, 58, 91...check valve.

Claims (1)

[Claims] 1. In a multi-cylinder compressor with multiple compression chambers, some of the discharge valves for the discharge port connecting the compression chamber of the cylinder block and the discharge chamber of the housing are always kept in the open position by springs. The housing has a first working chamber into which a spool integrally provided on the back surface of the discharge valve is slidably fitted, and a first working chamber on the back side of the first working chamber. A second working chamber is formed which communicates with the working chamber and the discharge chamber through holes, and communicates with the discharge system and suction system in the refrigeration circuit through a conduit including a switching valve, and controls the discharge pressure in the refrigeration circuit. The discharge valve is moved to the normal closed position by acting on the back surface of the spool through the second working chamber and the first working chamber, and a hole is formed in the second working chamber to communicate with the discharge chamber. From the room,
A check valve is provided to allow flow into the second working chamber and prevent flow in the opposite direction, and a check valve is provided in a passage connecting the discharge chamber and the discharge flange side to prevent displacement of the discharge valve to the normal closed position. A variable capacity compressor, characterized in that it is provided with a closing valve that correspondingly opens the passage.