JPH0429103Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Industrial Application Field) The present invention relates to an improvement of a variable capacity swash plate type compressor that adjusts the amount of refrigerant discharged according to the pressure state of the returned refrigerant.

(Prior Art) A variable capacity swash plate type compressor as shown in Fig. 2 has been proposed as a compressor used in recent automobile air conditioners (see, for example, Japanese Patent Laid-Open No. 158382/1982). .

This variable capacity swash plate compressor 3 adjusts the amount of refrigerant discharged from the compressor 3 by changing the internal volume of the compression chamber in the cylinder 25 in accordance with the suction pressure Ps of the refrigerant returned to the compressor 3. The suction pressure Ps is kept constant.

By keeping the suction pressure Ps constant in this way, the refrigerant pressure at the outlet of the evaporator (that is, the evaporation pressure of the refrigerant in the evaporator) becomes constant to a certain extent, making it possible to avoid freezing of the evaporator during so-called low loads.

This variable displacement swash plate type compressor 3 has a drive shaft 11 in a closed casing 17, which is rotationally driven by the engine via a belt, a pulley 2, and a magnetic clutch 2a. A drive rod 11 a is provided on the drive shaft 11 to protrude in a direction perpendicular to the drive shaft 11 and rotates together with the drive shaft 11 within the crank chamber 12 .

A drive swash plate 13 is connected to the drive rod 11a via a link (not shown) so that it can tilt and swing with respect to the drive shaft 11 with the pin 11b as a fulcrum, and the rotational force of the drive shaft 11 is connected to the drive rod 11a. The power is transmitted to the drive swash plate 13 via the drive rod 11a, pin 11b, etc. A non-rotating wobble plate 16 is slidably attached to the drive swash plate 13 via a thrust bearing 14 and a radial bearing 15.

The wobble plate 16 has a shoe 19 slidably connected to a guide pin 18 fixed to a closed casing 17 in which a crank chamber 12 is formed, and is prevented from rotating by this shoe 19. On the other hand, reciprocating motion in the axial direction is permitted. A plurality of piston rods 22 are attached to the wobble plate 16 via spherical bearings 22a at equal intervals in the circumferential direction, and a piston 23 is connected to the other end of the piston rod 22 via a spherical bearing 22b.

As the drive swash plate 13 rotates, the wobble plate 16 performs a so-called swash-like motion and reciprocates in the axial direction, thereby causing the piston 23 to reciprocate linearly via the piston rod 22. The front side portion of the piston 23 of the cylinder 25 into which this piston 23 is inserted becomes a compression chamber, and the back side portion becomes the crank chamber 12.
It communicates with

The cylinder head 30 is provided with a suction port 29 and a discharge port 33, into which the return refrigerant from the evaporator flows, and this refrigerant flows into the suction port 29 formed in the valve plate 20.
The air flows into the cylinder bore 26 against the closing elastic force of the suction valve 34 that closes the air intake valve 7 .

Further, this refrigerant is passed through a communication passage 32a that communicates with the suction port 29 formed in the cylinder head 30.
It is designed to be guided to the suction side pressure chamber 32 via.

On the other hand, the discharge port 33 is a part from which compressed refrigerant is discharged, and the discharge port 33 is a part from which compressed refrigerant is discharged.
It communicates with a pipe (none of which is shown) that sends the refrigerant discharged from a discharge port 28 opened to the condenser, and further communicates with the discharge side pressure chamber 35 via a communication passage 35a.

A control valve Cv as shown in FIGS. 2 and 3 is provided between the suction side pressure chamber 32 and the discharge side pressure chamber 35, and this control valve Cv
has a first control valve 36 at the bottom and a second control valve 3 at the top.
The first control valve 36 has a bellows 37 that expands and contracts according to the internal pressure of the suction side pressure chamber 32, and a spring 38 provided in the bellows 37. The degree of opening of the valve port 40 is adjusted, and the refrigerant in the suction side pressure chamber 32 is passed through the first valve port 40 through the passage 41, the through hole 42, the passage 43, the center hole 44 of the cylinder 25, and the center passage 45 of the drive shaft 11. It is designed to lead to the crank chamber 12 through.

Further, the first control valve 36 is provided with an actuation rod 46, and this actuation rod 46 causes the second control valve 3
9 is now open. Both control valves 36 and 39 operate in conjunction with each other, and when the first control valve 36 increases the opening degree of the first valve port 40 as described above, the second control valve 36 and 39 operate in conjunction with each other. 39 operates to reduce the opening degree of the second valve port 47.

Therefore, when the heat load in the cooling cycle is small, the pressure of the return refrigerant does not reach a sufficient amount of superheat and returns at a low pressure, so that the pressure in the suction side pressure chamber 32 (the above-mentioned suction pressure Ps) becomes lower, and the bellows 37 extends upward, as shown in FIG. 3A. As a result, the first control valve 36 closes the first valve port 40, and the valve operating rod 46 closes the first valve port 40, and the valve actuating rod 46 closes the _first valve port _40.
The second control valve 39 moves upward against the repulsive force of the second control valve 39.
The second valve port 47 opens wide to push up the high-pressure refrigerant (hereinafter referred to as discharge pressure
Pd) from this second valve port 47 to the passage 48,
49 into the crank chamber 12, and the internal pressure of this crank chamber 12 (hereinafter referred to as compressor internal pressure)
Pc).

Here, the inclination angle of the wobble plate 16 is controlled by the balance of pressures applied before and after the plurality of pistons 23, and if the pressure Pc in the crank chamber 12 becomes even slightly larger than the suction pressure Ps,
The combined force of the forces applied to the back surface of the plurality of pistons 23 acts on the wobble plate 16 as a moment about the pin 11b, and acts to reduce the inclination angle of the wobble plate 16.

For this reason, the high discharge pressure Pd is
2, the pressure balance acting on the front and rear surfaces of each piston 23 changes, and the pin 11b
The moment acting on the piston on the compression side and the piston on the suction side about Only a small compression stroke can be made. This reduces the amount of refrigerant compression,
The amount of refrigerant discharged is also small, and the flow rate of refrigerant circulating within the cooling cycle is reduced, resulting in an appropriate amount of refrigerant corresponding to the low heat load. Due to this decrease in the amount of refrigerant, the suction pressure Ps of the compressor 3 gradually increases, and as a result, the suction pressure Ps is kept constant.

Furthermore, when the heat load in the cooling cycle is large, the suction pressure Ps becomes high, and as shown in FIG. , the opening degree of the second valve port 47 becomes large, and the opening degree of the second valve port 47 becomes small, so that high discharge pressure is not introduced into the crank chamber 12, and the suction pressure Ps is transferred from the suction side pressure chamber 32 → the first valve port 40 → It is introduced into the crank chamber 12 through passage 41 → through hole 42 → passage 43 → center hole 44 → center passage 45, and the compressor internal pressure Pc becomes approximately equal to the suction pressure.

Therefore, the wobble plate 16 and the drive swash plate 13 are tilted to the maximum with respect to the drive shaft 11 due to the action of the moment described above, and the reciprocating stroke of the piston 23 becomes longer.

Therefore, if compression is performed in this state, the discharged refrigerant amount will increase, the refrigerant flow rate circulating within the cooling cycle will increase, and the refrigerant flow rate will be appropriate according to the high heat load, and the suction pressure Ps of the compressor 3 will increase. It gradually decreases, and as a result, the suction pressure Ps is kept constant.

(Problem to be solved by the invention) The above-mentioned conventional bellows type control valve
In CV, the set value is determined only by the resiliency of the bellows 37 and the spring 38, so that the set value is fixed.

Therefore, when controlling this control valve Cv, if the set value is lowered, the compressor will continue full stroke operation until the suction pressure Ps drops to that value, so cool down quickly. In this case, a lower set value is advantageous.

Once a predetermined cooling condition is obtained, the initial set value can be corrected to avoid unnecessarily continuing full stroke operation of the compressor.

However, with the fixed set value type, such operation is impossible, so the desired cool-down cannot be obtained, and there is a risk that a state of insufficient cooling power will continue.

The present invention was made to solve the above-mentioned drawbacks and problems of the prior art, and aims to shorten the cool-down time by making the set value of the control valve variable.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the invention forms a crank chamber in a sealed casing, a drive shaft is provided in the crank chamber, and a drive shaft is connected to the drive shaft. A drive swash plate with a variable inclination angle is attached to the drive swash plate, and a wobble plate, a piston rod, and a piston are connected in this order to the drive swash plate, and the rotation of the drive swash plate causes a plurality of pistons to be The piston is configured to linearly reciprocate, and the valve member is operated by a telescoping member that expands and contracts depending on the balance between the suction pressure of the refrigerant returning to the sealed casing and the spring pressure, and by opening and closing the valve member. A variable capacity control valve that controls the inclination angle of the driving swash plate by appropriately selecting the suction pressure or the discharge pressure discharged from the piston and guiding it into the crank chamber and adjusting the pressure in the crank chamber. The compressor is characterized in that the valve casing of the control valve is provided with an adjustment screw portion for adjusting the spring pressure of the telescopic member, and the adjustment screw portion is configured to be operated by an actuator.

(Function) In this way, when it is desired to cool down, the actuator is operated to lower the set value of the control valve, allowing a large amount of refrigerant to flow during the cooling cycle, and the desired cooling is achieved. After the condition is reached, the initial set value is restored, allowing operation without the need to operate the compressor unnecessarily.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of essential parts showing an embodiment of the present invention, and members common to those shown in FIGS. 2 and 3 are given the same reference numerals, and their explanations will be omitted.

The control valve 60 of the variable capacity swash plate type compressor shown in FIG. The valve members (first control valve 36 and second control valve 39
) is operated, and by opening and closing this valve member, the suction pressure Ps or the discharge pressure Pd discharged from the piston 23 is appropriately selected and guided into the crank chamber 12, and the pressure inside the crank chamber 12 is increased.
The inclination angle of the drive swash plate 13 is controlled by adjusting Pc.

In particular, in this embodiment, the bellows 37 is provided within the valve casing 61 of the control valve 60, and the spring pressure of the spring member 38 provided within the bellows 37 is adjusted.
The valve casing 61 is provided with an adjustment screw portion 62, and the adjustment screw portion 62 is rotated by an actuator 63.

The adjustment screw part 62 includes a support part 65 that supports the core rod 64 in the bellows 37, a support plate 66 that supports the spring 38 and to which the lower end of the bellows 37 is attached, and a support part 66 that supports the core rod 64 in the bellows 37. It has a protruding sleeve 68 having a threaded portion 67 bored in its inner circumferential surface, and a feed screw 69 screwed into the threaded portion 67 of this sleeve 68.

A pinion 70 is integrally provided at the end of this feed screw 69, and this pinion 70 is connected to a long driving gear 72 provided on a rotating shaft 71 of a stepping motor M serving as the actuator 63.
It is meshed with.

The stepping motor M includes a temp switch section 73 that turns on when the temp lever (not shown) is set to full cool and turns off when it moves and outputs a reverse rotation signal for the stepping motor M; An air conditioner switch section 74 that is turned on during operation is connected in series, and is activated when both switch sections 73 and 74 are turned on.

Next, the effect will be explained.

For example, in the summer when the outside temperature is high and the inside of the vehicle is in a high temperature state, and it is necessary to cool the inside of the vehicle immediately, the air conditioner switch section 74 is turned on.
Suppose you set the template lever to full cool.

As a result, the compressor starts rotating and the temp switch section 73 is turned on, so that the stepping motor M rotates by a predetermined amount.

This rotation is transmitted to the rotating shaft 71, drive gear 72, pinion 70, and feed screw 69, and moves the sleeve 68 downward in the figure.

As a result, the support plate 66 is displaced downward, the set value of the spring 38 is lowered, and as is clear from the above points, the bellows 37 operates the compressor at its full stroke until the suction pressure Ps reaches a considerably low pressure. It turns out.

As a result, when you want to cool down, a large amount of refrigerant is discharged into the cooling cycle.
The interior of the vehicle will be cooled rapidly. Further, when this cool-down is completed, if the template lever is moved to a position other than the full cool position, the stepping motor M is reversed by a signal from the template switch section 73 to reverse the feed screw 69, and the spring 3
This will return the set value of 7 to its original state. This allows the compressor to continue normal operation without operating with an unnecessarily large stroke.

[Effects of the invention] As described above, according to the invention, since the set value of the control valve is made variable, rapid cooling can be performed by operating the actuator to lower the set value of the control valve, and the desired temperature can be achieved. When the air conditioner enters the cooling state, the initial set value is restored, allowing operation without the need to operate the compressor unnecessarily.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing the main parts of an embodiment of the present invention, Fig. 2 is a sectional view showing a conventional variable capacity swash plate type compressor, and Figs. 3 A and B are schematic sectional views showing the main parts of the same compressor. It is a diagram. 11... Drive shaft, 12... Crank chamber, 13...
... Drive swash plate, 16 ... Wobble plate, 17 ... Casing, 22 ... Piston rod, 23 ... Piston, 36, 39 ... Valve member, 61 ... Valve casing, 62 ... Adjustment screw part, 63 ... Actuator, Cv……control valve, Pd……
Discharge pressure, PS... Suction pressure, M... Stepping motor.

Claims (1)

[Claims for Utility Model Registration] A crank chamber 12 is formed within a sealed casing 17, a drive shaft 11 is provided within this crank chamber 12,
A drive swash plate 13 is attached to the drive shaft 11 with a variable inclination angle, and a wobble plate 16, a piston rod 22, and a piston are connected to the drive swash plate 13 in this order. A plurality of pistons 23 are configured to linearly reciprocate via the wobble plate 16 and the piston rod 22, and the sealed casing 17
The valve members 36 and 39 are operated by the telescopic member 37 that expands and contracts depending on the balance between the suction pressure Ps of the refrigerant that returns to the piston 23 and the spring pressure. The discharge pressure Pd discharged from the crank chamber 12 is appropriately selected and guided into the crank chamber 12.
By adjusting the pressure within the drive swash plate 13
In a variable capacity compressor equipped with a control valve Cv that controls the inclination angle of the control valve Cv, the control valve CV
The telescopic member 3 is attached to the valve casing 61 of the Cv.
7. A control valve for a variable capacity swash plate type compressor, characterized in that an adjusting screw portion 62 for adjusting the spring pressure of No. 7 is provided, and the adjusting screw portion 62 is configured to be actuated by an actuator 63.