JPS6339795B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an improvement in a reciprocating compressor equipped with a plurality of compression chambers and a plurality of discharge chambers. The invention relates to a mechanism that reduces the start-up torque and eases the starting shock at startup.

Conventional Technology Compressors for vehicle air conditioning are generally operated by receiving power from the engine, but since the compressor is directly connected to the engine at a constant rotation ratio, When the electromagnetic clutch is connected to operate the compressor, at the same time as the electromagnetic clutch is connected, refrigerant gas is discharged at the full compression capacity given to the compressor, that is, 100
% operation status is obtained. But like this 100
% operation at the same time as the engine is started, it causes an overload on various parts of the engine and power transmission mechanism, giving the driver a shock similar to temporary engine braking, which may impair the driving feeling. , this may lead to problems such as accelerated wear of the clutch.

Also, as mentioned above, by starting the compressor at 100% operation, some of the refrigerant gas remains in a liquefied state in the compression chamber or in the suction pipe leading to the compressor. It is easy to induce so-called decompression, which occurs due to liquid compression, and various malfunctions (such as abnormal noise, damage to the compressor such as broken pistons, and operational problems caused by damage to the compressor) are likely to occur due to the compression of the liquid. This may result in damage to auxiliary equipment due to the compressor not being able to operate, engine overheating, etc.).

Conventionally, as a swash plate type compressor equipped with a shock relieving mechanism at startup, a compressor as shown in Japanese Unexamined Patent Publication No. 165587/1987 has been proposed. This compressor is equipped with multiple compression chambers and discharge chambers, and among the discharge valves for the discharge port connecting the compression chambers and discharge chambers, all rear discharge valves are moved to the open position via a spring when the compressor is stopped. In addition, during operation, front-side discharge pressure is applied to the back surface of the discharge valve to maintain the discharge valve in its normal closed position.

Problems to be Solved by the Invention In the above-mentioned swash plate compressor, when starting, the discharge gas from the front discharge chamber immediately acts on the back surface of the rear discharge valve, causing the rear discharge valve to return to its normal closed position. Therefore, there is a problem that the starting torque reduction effect is small because the operation is immediately shifted to 100% operation.

In addition, since the piston reciprocates even in the cylinder on the side where compression operation is stopped, the suction valve is pushed down from the suction chamber during the suction process, and the discharged gas in the discharge chamber, which has no resistance member, exceeds the amount of suctioned gas sucked into the compression chamber. Inhale. Therefore, the supply of cold low-pressure gas flowing from the suction chamber to the compression chamber and cold oil dissolved in the gas decreases accordingly, resulting in insufficient lubrication of the cylinder on the idle side, reducing durability and causing seizure. There is a risk that an accident may occur.

Furthermore, since the variable capacity compressor described above has a structure in which the discharge valve on the rest side reciprocates between the normal closed position and the open position, it is necessary to provide a mechanism to prevent rotation of the discharge valve. This not only increases the number of parts and complicates the structure, but also requires space to move the discharge valve in the axial direction, resulting in an increase in size.

The present invention has a 0% compression operation on the rear housing side.
The problem to be solved is to reduce the switching speed of a switching valve that controls 100% compression operation to 100% compression operation and to automatically return to 0% compression operation.

Means for Solving the Problem The discharge valve is fixed to the valve plate, and the rear side discharge chamber and the swash plate chamber or the crank chamber are communicated through a bypass passage formed in the valve plate and the cylinder block, and the discharge chamber is provided with the A bypass switching valve is provided which opens and closes the bus pass passage so as to be able to come into contact with and separate from the valve plate, and the switching valve is floated to the open position via a spring when the compressor is stopped, and when the compressor is in operation. The switching valve is held in the normal closed position by applying discharge pressure to the back chamber of the bypass switching valve through the throttle passage, and the communication hole that connects the back chamber of the bypass switching valve and the suction chamber is connected to the suction chamber. It is configured to open and close using a pilot switching valve that operates by directly detecting changes in pressure.

Operation When the compressor is started while the compressor is stopped and the bypass switching valve is floated and held in the open position by the spring, the gas sucked into the compression chamber from the suction chamber passes through the discharge valve from the discharge port. It is pushed away and flows into the discharge chamber, and further flows into the swash plate chamber or crank chamber via the bus pass passage, from there it is returned to the suction chamber via the suction passage, and then sent to the compression chamber again.
Due to this unidirectional gas flow, cold low-pressure gas and cold oil dissolved in the gas are always supplied into the compression chamber, and lubrication is performed smoothly.

In addition, the discharge gas discharged from the compression chamber to the discharge chamber via the discharge port and the discharge gas sent from the front side discharge chamber to the rear side discharge chamber via the discharge passage are connected to the bypass switching valve when flowing down to the bus pass passage. The gas flow is in the same direction as the moving direction, and this gas flow applies an acting force to the bypass switching valve to draw it toward the valve plate. However, since the back chamber of the switching valve is in communication with the discharge chamber only through the throttle passage, there is a negative pressure in the back chamber, and the switching valve moves at a speed commensurate with the amount of gas sucked from the throttle passage. The pump moves slowly toward the position where the bypass passage is closed against the pressure, and gradually increases the discharge pressure in the discharge chamber, so that the shock at startup is alleviated.

Next, the electromagnetic clutch is turned off, and when the compressor stops, the pressure in the suction chamber is increased by the pressure from the cooling circuit. Due to this suction pressure change, the pilot switching valve that had been blocking the pressure guiding hole that communicates the back chamber and the suction chamber is lifted up, and in order to open the pressure guiding hole, the discharge pressure in the back chamber is directed to the suction chamber. This allows the bypass switching valve to move in the direction of opening the bypass passage.

Embodiment Hereinafter, an embodiment embodying the present invention will be described based on the drawings. First, a practical example of a swash plate compressor with three or six cylinders on one side will be explained. In the figure, both ends of opposed cylinder blocks 1 and 2 are closed by both front and rear housings 5 and 6 via valve plates 3 and 4.
These are assembled with an appropriate number of bolts 18. A swash plate chamber 7 is formed at the joint portion of the cylinder blocks 1 and 2, and the swash plate chamber 7 is inclined with respect to a drive shaft 8 passing through shaft holes 1a and 2a formed through the centers of the cylinder blocks 1 and 2. A fixed swash plate 9 is housed therein. Radial bearings 12 and 13 that support the drive shaft 8 are press-fitted into the boss portions 10 and 11 of the cylinder blocks 1 and 2 through which the drive shaft 8 passes, and between the boss portions 10 and 11 and the swash plate 9, Thrust bearings 14 and 15 are interposed. Three pairs of cylinder bores (hereinafter referred to as compression chambers 16) are bored in the cylinder blocks 1 and 2 parallel to the drive shaft 8 and at radial positions centered on the drive shaft 8, and are inserted into the compression chambers 16. The piston 17 is moored to the swash plate 9 via a bearing device consisting of balls and shoes, and the piston 17 can reciprocate within the compression chamber 16 by the rotational force of the swash plate 9. Discharge chambers 22, 23 are formed in the center of each of the front and rear housings 5, 6, and substantially annular suction chambers 20, 21 are formed on the outer periphery so as to surround the discharge chambers 22, 23. In particular, the rear suction chamber 21 is formed in an annular shape, and the rear discharge chamber 23 is formed in a cylindrical shape. Suction chamber 20,
21 communicates with the swash plate chamber 7 through suction passages 24 and 25 formed in the cylinder blocks 1 and 2, and the swash plate chamber 7 is connected to a suction flange (not shown) mounted near the mating surfaces of the cylinder blocks 1 and 2. ) is communicated with.

Further, the discharge chambers 22 and 23 are connected to openings (not shown) formed in the valve plates 3 and 4 and to the cylinder blocks 1 and 4.
The bore in 2 is connected to a communication passage 30 in a discharge flange 29 attached near the mating surface of the cylinder blocks 1 and 2 via a discharge passage (not shown) formed using one of the gaps. It's communicating.

Further, an external passage 31 of the discharge flange 29 that communicates with the cooling circuit is provided with a check valve 32 for opening and closing the passage 31.
3 and the discharge passage, etc., when the pressure is low, the external passage 31 is closed, and when the pressure is high, the passage 31 is opened.

Suction ports 34, 35 and discharge ports 36, 37 are provided through the valve plates 3, 4, through which the cylinder bore 16a communicates with the suction chambers 20, 21 and discharge chambers 22, 23, 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. Furthermore, the discharge valves 40 and 41 are provided with a valve holder 4.
The amount of deformation is regulated by 2,43,
On the front side, it is narrowly fixed between the valve plate 3 and the front housing 5, and on the rear side, it is fixed to the valve plate 4 with bolts 44. Further, a communication hole 45 coaxial with the drive shaft 8 is bored in the center of the rear side valve plate 4, and communicates between the discharge chamber 23 and the shaft hole 2a formed in the center of the cylinder block 2. That's what I do. By spacing the rear end of the drive shaft 9 a certain distance from the valve plate 4, a part of the shaft hole 2a is formed into a circular space 46. A communication passage 47 that communicates the circular space 46 with the swash plate chamber 7 is formed in at least one location between the bores of the rear cylinder block 2. A bypass passage 48 formed by the communication hole 45, the circular space 46, and the communication passage 47 allows the discharge chamber 23 and the swash plate chamber 7 to communicate with each other.
A communication hole 45 (bypass passage 48) formed in the valve plate 4 is provided in a circular recess 61 formed in a portion of the wall portion 6a forming the discharge chamber 23 of the rear housing 6 in a portion facing the communication hole 45. A bypass switching valve 52 that opens and closes is fitted so as to be movable in the axial direction. A spring 54 is interposed between the bypass switching valve 52 and a spring receiver 53 fitted into the circular space 46, so that the bypass switching valve 52 is always held floating in the open position. The spring receiver 53 has a small hole 53a that communicates the circular space 46 with the shaft hole 2a.

The wall portion 6a of the rear housing 6 has a small diameter hole that communicates between the first back chamber 51 formed between the back surface of the bypass switching valve 52 and the bottom wall of the circular recess 61 and the suction chamber 21. A pressure guiding hole 55 is provided,
This pressure guiding hole 55 is connected to the suction chamber 2 of the rear housing 6.
The pilot switching valve 5 is fitted into a circular recess 62 formed coaxially with the pressure guiding hole 55 in the outer wall portion 6b forming the pilot switching valve 5 so as to be movable in the axial direction.
It is opened and closed by 6. In the figure, reference numeral 57 denotes a second back chamber, which is formed between the back surface of the pilot switching valve 56 and the bottom wall of the circular recess 62.
A spring 58 provided inside the pilot switching valve 56 causes the front surface of the pilot switching valve 56 to always be connected to the pressure guiding hole 55.
is biased in the direction of closing.

Note that when the pilot switching valve 56 is in a state where the pressure guiding hole 55 is closed, the front outer peripheral portion of the switching valve 56 that does not close the pressure guiding hole 55 protrudes from the wall 6a of the rear housing 6. It is formed so as to be separated from the wall surface 6a by a protrusion 6c or the like.

In the figure, 59 is a throttle passage formed in the pilot switching valve 56 and communicating the suction chamber 21 and the second back chamber 58, and 60 in the figure is a throttle passage formed in the bypass switching valve 52 and connecting the discharge chamber 23 and the first back chamber. 51, and both chambers 21 and 5 communicate with each other.
Gas flows according to the pressure difference between 7, 23 and 51. Further, the passages 59 and 60 do not necessarily need to be formed in the switching valves 56 and 60, and may be formed in the rear housing, or the passages 59 and 60 may be formed in the circular recess 6.
The gaps between the switching valves 56, 52 and the switching valves 56, 52 may be used.

Next, the operation of the swash plate compressor constructed as described above will be explained.

When stopped, the bypass switching valve 52 is held floating by the spring 54 in a position where it opens the bypass passage 48, as shown in the figure, and the pilot switching valve 56
is pressed and held by a spring 58 so as to close the pressure guiding hole 55, and the check valve 32 of the discharge flange 29 closes the external passage 31.

Therefore, the internal pressures of the discharge chamber 23, the first rear chamber 51, the swash plate chamber 7, the suction chamber 21, and the second rear chamber 57 are balanced.

In this state, when the electromagnetic clutch is turned on and the compressor starts operating, the rear discharge chamber 2
3 is in communication with the swash plate chamber 7 via the bypass passage 48, so the discharge gas compressed on the front side is discharged from the discharge chamber 22 → discharge passage → communication passage 30 →
The gas is guided to the rear discharge chamber 23 and flows down to the swash plate chamber 7 through the bypass passage 48 together with the discharge gas discharged from the rear compression chamber. This gas is guided into the suction chambers 20, 21 through the suction passages 24, 25,
It flows into the compression chamber 16 again. Therefore, the front
There is no effective compression operation on either the rear side,
Dry operation (0% compression operation) occurs in the discharge chambers 22 and 23.
pressure does not increase. At this time, a unidirectional gas flow from the discharge chamber 23 to the swash plate chamber 7 is formed in the bypass passage 48, and this gas flow flows through the bypass switching valve 52.
In order to generate a force that moves the valve 52 in the same direction as the moving direction of the valve 52, that is, to the left (in the figure), the switching valve 52 tries to move to the left due to the gas flow. Since the pressure guiding hole 55 is closed and the first back chamber 51 has no communication with the outside except for the throttle passage 60, the switching valve 52
It can only move by an amount commensurate with the amount of gas supplied from the throttle passage 60 due to the differential pressure between the first back chamber 51 and the discharge chamber 23 accompanying the movement.

Therefore, the switching valve 52 gradually approaches the valve plate 4 depending on the amount of gas, and finally approaches the communication hole 45.
, and the bypass passage 48 is cut off.

Since the bypass switching valve 52 approaches the valve plate 4 at a slow moving speed, the discharge chamber 23
The pressure also gradually increases, that is, effective compression operation gradually starts, and when the bypass passage 48 is completely closed, normal compression operation (100% compression operation) begins.
becomes. Therefore, since it takes a certain amount of time to go from 0% compression operation to 100% compression operation, the startup torque at startup is small, the startup shock is relaxed, and no liquid compression occurs.

After the bypass switching valve 52 closes the bypass passage 48, the first back chamber 51 is closed by the throttle passage 60.
The pressure is also the same as the pressure in the discharge chamber 23, and the switching valve 52 is displaced to the normal closed position against the spring 54 due to the pressure difference between the circular space 46 and the discharge chamber 23, that is, pressed against the valve plate 4. Since the communication hole 45 is maintained in a closed state, a normal compression operation is started, and the check valve 32 of the discharge flange 29 is pushed up by the discharge pressure to open the external passage 31, and the compressor Operated at % capacity.

At this time, the pressure guiding hole 55 communicating with the first back chamber 51 also becomes high pressure (discharge pressure), and pressure is applied to the pilot switching valve 56, but the pressure receiving area of the switching valve 56 relative to the pressure guiding hole 55 is small, and the spring 58 Since the pressure is not large enough to overcome the biasing force, the pressure guiding hole 55 of the switching valve 56 remains closed.

Next, when the electromagnetic clutch is turned off and the compressor is stopped, the pressure in the suction chamber 21 rapidly increases due to the supply pressure from the cooling circuit and the stoppage of the flow into the compression chamber. At this time, the pressure in the second rear chamber 57 on the pilot switching valve 56 side causes a time delay in rising due to the throttling effect of the throttle passage 59, and becomes lower than the pressure in the suction chamber 21, and the pressure in the second rear chamber 57 on the pilot switching valve 56 side is lower than that in the suction chamber 21.
Since discharge pressure is applied to the front side of the valve, this pressure difference causes the switching valve 56 to move to the right (in FIG. 1) against the spring 58, and the pressure guiding hole 5
5 is opened, the high-pressure gas sealed in the first back chamber 51 leaks into the suction chamber 21, and as a result, the pressure in the suction chamber 21 further increases, and the pressure difference also increases, causing the pilot switching valve 56 to close. The pressure hole 55 is kept open.

Therefore, the pressure in the first back chamber 51 is balanced with the pressure in the suction chamber 21, and the biasing force of the spring 54 causes the bypass switching valve 52 to move to the right (in FIG. 1).
to open the communication hole 45. By opening the communication hole 45, the bypass passage 48 becomes in a communicating state, so that the gas in the discharge chambers 22 and 23 flows down to the swash plate chamber 7 through the passage 48, and the pressure in the discharge chamber drops to the swash plate chamber 7 as soon as the electromagnetic clutch is turned off. Internal pressure (suction pressure)
The pressure becomes the same as that, and compression becomes impossible.

Moreover, the pressure difference between the first back chamber 51 and the suction chamber 21 is eliminated, and the second back chamber 57 is
As the pressure inside the second rear chamber 57 approaches the pressure inside the suction chamber 21 due to the gas flowing into the valve, the pressure and the biasing force of the spring 58 move the pilot switching valve 56 to the left and open the pressure guiding hole. 55 will be closed.

Although the above embodiments have been described in detail with respect to a swash plate type compressor, it should be noted that the present invention is also fully applicable to a reciprocating type compressor.

Effects of the Invention In the present invention, the compression chamber and the discharge chamber are closed by a discharge valve, the discharge chamber and the swash plate chamber (or crank chamber) are communicated with each other through a bypass passage, and the passage is diagonally connected to the discharge chamber. A bus path switching valve that can be moved in the same direction as the gas flow leading to the plate chamber can be opened and closed, and the first back chamber formed on the back of the switching valve and the suction chamber are communicated through a pressure guiding hole, and the pressure guiding The electromagnetic clutch can be turned off by making the hole openable and closable using a pilot switching valve that operates by detecting suction pressure fluctuations.
At the same time as the compressor is stopped, a change in suction pressure in the suction chamber is detected, and the pilot switching valve immediately moves against the spring to communicate the first back chamber on the side of the bypass switching valve with the suction chamber. By reducing the back chamber pressure, the bypass switching valve can open the bypass passage, and the discharge chamber pressure becomes the same pressure as the swash plate chamber pressure (suction pressure), allowing the bypass switching valve to maintain the bypass passage open state. . Therefore, it is possible to control the first back chamber of the bypass switching valve without using expensive equipment such as an electromagnetic switching valve (using only the suction pressure existing in the compressor), and there is no possibility of erroneous switching to unloading. It can be done.

Furthermore, when starting the compressor, even if the piston enters the suction stroke and the pressure in the compression chamber becomes low, refrigerant gas is allowed to be sucked from the suction chamber, but the discharge valve prevents suction of discharge gas from the discharge chamber. At the same time, the gas flowing from the compression chamber to the discharge chamber is passed through a bypass passage →
The gas is circulated in the order of swash plate chamber → suction passage → suction chamber and returned to the compression chamber, making the gas flow a long one-way path. Therefore, the compression chamber is always supplied with cold, low-pressure gas from the suction chamber. The suction can smoothly lubricate the compression chamber and each bearing, increasing durability, and since the bypass switching valve is moved by the unidirectional gas flow described above, it is possible to smoothly lubricate the compression chamber and each bearing. Since the time until the bypass passage is closed by the bypass switching valve is long and the switching valve gradually approaches the passage, the pressure in the discharge chamber gradually increases, and the load on the engine gradually increases. Therefore, the startup shock can be made extremely small.

[Brief explanation of the drawing]

The figure is a longitudinal sectional view showing a swash plate compressor which is an embodiment of the present invention. 4... Valve plate, 7... Swash plate chamber, 20, 21... Suction chamber, 22, 23... Discharge chamber, 29... Discharge flange, 30... Communication passage, 31... External passage, 32
... Check valve, 40, 41 ... Discharge valve, 48 ... Bypass passage, 51 ... First back chamber, 54 ... Spring, 55 ... Pressure guiding hole, 56 ... Pilot switching valve, 59, 60 ...Aperture passage.

Claims (1)

[Claims] 1. In a reciprocating compressor that is equipped with a plurality of compression chambers, suction chambers, and discharge chambers, and in which the swash plate chamber or crank chamber and the suction chamber are communicated through a suction passage, the plurality of discharge chambers are communicated with each other, and one of the discharge chambers is connected to the suction passage. The chamber communicates with the swash plate chamber or the crank chamber through a bypass passage, and the discharge chamber is provided with a discharge valve fixed to the valve plate and a bypass switching valve for opening and closing the bypass passage. The switching valve is biased by a spring in the direction of opening the bypass passage, and at the time of startup, the switching valve is moved in the direction of closing the bypass passage by the unidirectional gas flow flowing through the bypass passage, and at the same time, the switching valve is biased. By applying discharge pressure to the first rear chamber of the bypass switching valve through the throttle passage, the switching valve is held in the normal closed position during operation, and furthermore, the switching valve is kept in the normal closed position by applying discharge pressure to the first rear chamber of the bypass switching valve and the suction passage. A communication path that connects the plurality of discharge chambers to each other through a pressure guiding hole, which can be opened and closed by a pilot switching valve located in the suction chamber and operated by directly detecting a change in suction pressure. A reciprocating compressor comprising a check valve that opens the passage in response to displacement of the bypass switching valve to a normal closed position in an external passage formed in a discharge flange communicating with the reciprocating compressor.