JPH09209926A - Swash plate type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swash plate type compressor excellent in its seizure avoiding property and durability. SOLUTION: A swash plate 2 connected to a shaft 1 rotatably journaled after passing a crank chamber 3, and a piston 6 in which connection parts 9, 10 connected to each other via sliding shoes 4, 5 are formed so that the swash plate 2 may make sliding motion inside, are provided and on the swash plate 2, a flat plate part 2b sandwiched between sliding shoes 4, 5 with free slidable contact with those shoes is formed and the abovementioned flat plate part 2b includes a white metal thermal sprayed film coated and impregnated with molybdenum disulfide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate compressor, and more particularly to improvement of a swash plate portion of a swash plate compressor.

[0002]

2. Description of the Related Art As a compressor for an air conditioner for an automobile, a single-head type variable capacity swash plate compressor which has a swash plate whose inclination angle is variable with respect to a shaft and which is lightweight and can rotate at high speed is becoming mainstream. is there.

This variable displacement swash plate compressor is shown in FIG.
, The swash plate 2 rotated by the shaft 1 is
It is provided in the crank chamber 3 with a variable inclination angle and is connected to the piston 6 via sliding shoes 4 and 5.

The piston 6 comprises a piston head 8 which reciprocates in the cylinder chamber 7 and connecting portions 9 and 10 which engage with the swash plate 2 and have a substantially U-shaped cross section. Two spherical concave portions 9s, 1 formed at opposite positions of
Almost hemispherical sliding shoes 4 and 5 are fitted to 0s, and the swash plate 2 is attached by these sliding shoes 4 and 5.
Both front and back flat surfaces are sandwiched.

That is, both side surfaces of the flat plate portion 2b of the swash plate 2 are
Sliding Sliding shoes 4, 5 have circular flat portions 4a, 5a in sliding contact. On the other hand, spherical concave portions 9s and 10s are formed in the connecting portion 9 of the piston, and the spherical convex portions 4b and 5b of the sliding shoes 4 and 5 are in sliding contact with each other.

Therefore, by causing the swash plate 2 to perform a so-called rasping rotary motion around the shaft 1, the piston head 8 can be linearly reciprocated in the cylinder chamber 7. Then, when the inclination angle of the swash plate 2 is changed, the stroke amount of the piston 6 is adjusted, so that the discharged refrigerant amount is changed.

On the other hand, the connecting portions 9 and 10 are farthest from the cylinder chamber side and the top dead center position (upper piston position in FIG. 4) in sliding contact with the outer edge portion of the swash plate 2 closest to the cylinder chamber side. Reciprocating linear movement is performed between the outer edge portion of the position and the bottom dead center position (the piston position on the lower side in FIG. 4) in sliding contact.

Therefore, the sliding shoes 4, 5
However, in order to maintain a good engagement state without dropping from the connecting portions 9 and 10 of the piston 6, as shown in FIG. 4, the spherical convex portions 4b and 5b of the sliding shoes 4 and 5 are provided.
Must be configured to form part of the spherical surface of the same sphere.

[0009]

However, as clearly shown in FIG. 5, when the swash plate 2 in which the piston 6 is at the top dead center position is tilted to the maximum, the spherical concave portion 10s of the connecting portion 10 and the sliding shoe 5 are separated from each other. The running allowance S and the running allowance S between the spherical recess 9s of the connecting portion 9 and the sliding shoe 4 at the bottom dead center position are extremely small.

Therefore, when lubrication is insufficient such as during a sudden start, an excessive temperature rise due to frictional heat causes seizure between the swash plate 2 and the sliding shoes 4, 5 and the sliding shoes 4, 5. 5 is pushed out in the direction of the arrow in the figure, and the spherical concave portions 9s, 1 having the smaller engagement margin S are formed.
There is a problem that the sliding shoe is caught near the end portion of the shaft 1 side of 0 s and the sliding shoe is caught or dropped.

Further, excessive frictional heat may be conducted to the piston 6 via the sliding shoes 4, 5, and additional seizure may occur between the sliding shoes 4, 5 and the piston 6. Have

On the other hand, it is possible to plate the surface of the swash plate 2 with copper having a large thermal conductivity and an excellent anti-seizure property to suppress the seizure, but it has a problem in durability due to its weak adhesion.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a swash plate type compressor excellent in seizure prevention and durability.

[0014]

The present invention for achieving the above object is constructed as follows for each claim.

According to the first aspect of the present invention, the shaft rotatably mounted through the crank chamber, the swash plate arranged in the crank chamber and connected to the shaft, and the rotation of the shaft A hinge mechanism transmitting to the swash plate;
A swash plate type compressor having a plurality of pistons axially reciprocating inside a cylinder chamber, wherein a connecting portion is formed so that the swash plate is slidable inside and is connected via a sliding shoe. The plate is formed with a flat plate portion slidably contacting and sandwiched with the sliding shoe, and the flat plate portion has a sprayed coating formed by spraying a metal having a large thermal conductivity, A lubricant is applied and impregnated on the surface of the sprayed coating.

In the invention thus specified, the film formed on the surface of the swash plate is coated and impregnated with a lubricant to improve the lubricating action, while the thermal conductivity of the metal forming the film is increased. Therefore, it is difficult to cause a local temperature rise due to frictional heat. Further, since the coating is formed by thermal spraying, the swash plate and the coating have a strong adhesive force.

According to a second aspect of the present invention, in the swash plate compressor according to the first aspect, the metal is a copper alloy. In the invention thus specified, the antifriction property can be improved.

According to a third aspect of the invention, in the swash plate compressor according to the second aspect, the copper alloy contains copper as a main component and contains tin. In the invention thus specified, the antifriction property at high load and high speed rotation can be improved.

The invention described in claim 4 is the above-mentioned claim 1-
In the swash plate compressor according to any one of 3 above, the lubricant is a solid lubricant having a layered structure. In the invention thus specified, the lubricant is easily sheared, so that the lubricating action can be improved.

According to a fifth aspect of the present invention, in the swash plate compressor according to the fourth aspect, the solid lubricant is molybdenum disulfide. In the invention specified in this way, since the coefficient of friction is low,
The lubricating action can be improved.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an embodiment of a variable capacity swash plate compressor according to the present invention, and FIG.
6 is an enlarged view of a main part of FIG. 3, and members common to the members shown in FIGS. 3 to 5 are denoted by the same reference numerals.

The embodiment of the variable displacement swash plate compressor according to the present invention is a single-headed type as shown in FIG. 1, and includes a cylinder block 21, a rear housing 20r located on the right end side of the cylinder block 21, It has a front housing 20f located on the left end side. Also,
Both housings 20r and 20f are connected by a bolt V.

At the center of the front housing 20f,
A through hole 23 for inserting the shaft 1 is formed. A radial bearing 24 that rotatably supports the shaft 1 is press-fitted into the through hole 23, and an oil seal 25 is also disposed in the vicinity. Also, the front housing 2
The space surrounded by the inner wall of 0f and facing the cylinder block 21 is the crank chamber 3, and a hinge mechanism K for transmitting the rotation of the shaft 1 to the swash plate 2 is provided.

In the hinge mechanism K, the base end is fitted to the shaft 1 and the distal end 26a has a long hole 26b. The rotary arm 26 and the rear end of the journal 2a of the swash plate 11 extend from the distal end of the rotary arm 26. 26a, and the elongated hole 26
The driven arm 29 having a hole corresponding to b and the long hole 2
6b is inserted through the pin 30.

The shaft 1 is provided with a spherical bush 28 repelled by the springs B1 and B2 so as to be slidable in the axial direction of the shaft. The spherical surface of the spherical bush 28 is opposed to the inner peripheral surface of the central hole O opened at the center of the journal portion 2 a of the swash plate 2. The journal portion 2a and the spherical bush 28 are located between the journal portion 2a and the spherical bush 28.
With a pair of pins 31 protruding along the central axis of
Since they are connected, the swash plate 2 can rotate about the pin 31 while being rotated by the shaft 1. In other words, the pin 31 is used as a fulcrum to incline, and the inclination angle (inclination angle with respect to the plane orthogonal to the axis of the shaft 1) can be adjusted.

A thrust bearing 31t is provided between the inner wall surface of the front housing 20f and the rotary arm 26.

The other end of the shaft 1 is connected to the cylinder block 2
1, is rotatably supported by a radial bearing 31r, and a thrust bearing 32 is provided on the end surface of the shaft 1.

A plurality of cylinder chambers 7 are provided in the cylinder block 21 at equal intervals in the circumferential direction, and pistons 6 are installed in the respective cylinder chambers 7. The piston 6 is provided in the cylinder block 21 and both housings 2.
It is made of an aluminum alloy similar to that of 0r and 20f, and has a coating layer (for example, made of fluororesin) formed on its surface to improve slidability when the piston reciprocates.

The sliding shoes 4, 5 connecting the piston 6 and the swash plate 2 are flat surfaces 4a, 5a which are finished so as to slide on the flat plate portion 2b of the swash plate 2.
And spherical convex surfaces 4b and 5b which are fitted in concave and convex with the spherical concave portions 9s and 10s of the connecting portions 9 and 10, so that only the swash plate 2 converts the slewing rotational movement into the reciprocating linear movement of the piston. ing. The spherical concave portions 9s and 10s are processed so as to form one spherical surface, whereby the swash plate 2 is formed.
It is connected so that there is no play regardless of the inclination angle of.

At one end surface of the cylinder chamber 7, a suction port 35 for sucking the refrigerant, a discharge port 36 for discharging the refrigerant, and a suction port for controlling the flow of the refrigerant to the suction port 35 and the discharge port 36. A valve plate 39 including valve forming plates 37 and 38 in which a plurality of valves and discharge valves are formed is provided.

The return refrigerant from the evaporator is used as the suction chamber 4
0 through the suction port 35, and flows into the cylinder chamber 7 in the suction process against the elastic closing force of the suction valve formed in the valve forming plate 37 on the left side of the valve plate 37 in the figure. It is supposed to do. On the other hand, the refrigerant compressed by the piston is discharged through the discharge port 36 against the elastic closing force of the discharge valve formed on the valve forming plate 38 on the right side of the valve plate 37 in the drawing, and the discharge chamber is discharged. 41.

Further, in the rear housing 20r, a control valve Cv for adjusting the pressure state in the crank chamber 3 and adjusting the inclination angle of the swash plate 2 is installed. This control valve Cv changes the angle of the swash plate 2 by adjusting the pressure in the crank chamber 3 according to the suction pressure of the returning refrigerant, adjusts the amount of refrigerant discharged from the compressor, and sucks in the compressor. The pressure is controlled to be constant.

Therefore, the swash plate 2 receives a reaction force due to refrigerant compression from the piston 6 in the compression stroke, and a moment M1 acts around the hinge mechanism K. This moment M1 is generated by the piston 6 located farther from the pin 30 of the swash plate 2.
Is larger, it acts clockwise in FIG. Further, the moment M2 acts counterclockwise due to the elastic force of the spring B1. The crank chamber 3 and the suction chamber 4
The moment M3 generated by the pressure difference of 0 is
Since the pressure of 0 and the pressure of the crank chamber 3 are almost equal, they can be ignored.

On the other hand, the moment M2 due to the elastic force of the spring B1 is set to be less than the moment M1 due to the reaction force due to the compression of the refrigerant, so that the swash plate 2 acts clockwise around the hinge mechanism K. Depending on the moment
The inclination angle becomes large. As a result, the pin 3 of the hinge mechanism K is
0 contacts the upper end of the long hole 26b, and the stroke of the piston 6 increases. Therefore, the amount of discharged refrigerant increases,
The refrigerant flow rate circulating in the cooling cycle also increases, an appropriate refrigerant flow rate according to the heat load is discharged, the suction pressure of the compressor gradually decreases, and the suction pressure is finally maintained at a constant value.

Next, the structure of the swash plate 2 will be described.

The swash plate 2 is constructed by forming a cast iron journal portion 2a and a steel plate portion 2b made of steel having a high Young's modulus separately, and connecting both by a screw portion N. That is, the flat plate portion 2b of the swash plate 2 is made of a material having a high Young's modulus that can withstand a large compression reaction force, that is, a material having high mechanical strength such as tensile strength and bending rigidity, specifically, carbon steel, The material of the journal portion 2a, which is made of steel such as alloy steel, and which is relatively unloaded, is made of cast iron.

Further, as shown in FIG. 2, the flat plate portion 2 which is slidably contacted with and sandwiched by the sliding shoes 4, 5.
A sprayed coating L1 is formed on b. This film L1
The sprayed metal forming the is composed of a copper alloy having a good antifriction property and a high thermal conductivity. This copper alloy is an alloy containing 80% or more of copper as a main component and containing tin from the viewpoint of bearing performance under high load and high speed rotation.
For example, it is possible to use a white metal system containing zinc and tin. Further, since the coating film is formed by thermal spraying, the swash plate and the coating film have a strong adhesive force, unlike plating, and thus have excellent durability.

Further, a lubricating thin film L2 made of a thin film in which a solid lubricant is dispersed is formed on the sprayed coating L1 to improve the lubricating action. This solid lubricant is made of a substance having a layered structure that is excellent in lubricity and is easily sheared. For example, graphite can be used, but molybdenum disulfide is used because of its friction coefficient. In addition, the lubricating thin film L2 is
For example, after dispersing the solid lubricant in a solvent and applying it directly,
For example, it is possible to form by spraying and impregnating the surface of the sprayed coating with a solid lubricant by naturally drying or firing to remove the solvent.

Next, the operation of the compressor will be described.

An electromagnetic clutch (not shown) is turned on, and the shaft 1 is rotated by an engine (neither is shown) via a belt and a pulley. Along with this, the rotating arm 2
6 rotates to cause the swash plate 2 to rotate via the hinge mechanism K. At this time, if the swash plate 2 is inclined with respect to the shaft 1, the swash plate 2 pivots in a rasping motion, causing the piston 6 to reciprocate and being sucked into the cylinder chamber 7 from the suction port 35. The refrigerant is compressed and discharged into the discharge port 3
6 is discharged into the discharge chamber 41.

Since the sliding shoes 4 and 5 only slide on the flat plate portion 2a of the swash plate 2 even if the swash plate 2 rotates, no rotational force is transmitted to the piston 6. Further, when the heat load in the cooling cycle is higher than the preset temperature, the suction pressure of the refrigerant is high, but the control valve Cv acts to introduce a relatively high suction pressure into the crank chamber 14. Therefore, the internal pressure becomes substantially equal to the suction pressure.

Therefore, the piston 6 in the suction process
Has almost no pressure difference between the front and the rear, and can smoothly retreat in the cylinder chamber 7, increasing the stroke. Further, if compression is performed in this state, the amount of discharged refrigerant increases, the flow rate of the refrigerant circulating in the cooling cycle also increases, and the proper refrigerant flow rate according to the heat load is again discharged, so the compressor is discharged. Suction pressure gradually decreases,
Finally, the suction pressure is kept constant.

On the other hand, when the heat load in the cooling cycle becomes small or the refrigerant becomes excessive due to the high-speed rotation of the compressor, the pressure of the return refrigerant cannot return a sufficient amount of superheat and returns at a low pressure. And the pressure in the suction chamber 40 becomes low. In this case, the high pressure refrigerant compressed by the piston 6 and guided to the discharge port 36 is introduced into the crank chamber 3 by the action of the control valve Cv, so that the internal pressure of the crank chamber 3 is increased.

Therefore, a difference occurs in the moment of the force applied to the piston 6, and at a certain point, the sum of the moment M2 due to the repulsive force of the spring B1 and the moment M3 caused by the pressure difference between the crank chamber 3 and the suction chamber 40. , A moment that acts counterclockwise about the hinge mechanism K is generated in excess of the moment M1 due to the reaction force due to the refrigerant compression, and the inclination angle of the swash plate 2 is reduced. As a result, the stroke of the piston 6 becomes smaller and the amount of discharged refrigerant decreases, so that the suction, compression and discharge of the refrigerant are slid by the swash plate 2 inclined with respect to the shaft 1 and the cylinder chamber 7 as described above. This is done by making sliding contact with the piston 6 whose movement direction is regulated via the sliding shoes 4 and 5, and converting the slewing rotational movement of the swash plate 2 into the reciprocating movement of the piston 6.

In this case, even if the lubrication is insufficient, since the spray coating L1 and the lubricating thin film L2 are formed on the swash plate 2, there is a gap between the swash plate 2 and the sliding shoes 4, 5. No seizure will occur. Therefore, even when the piston 6 is at the top dead center position or the bottom dead center position, the sliding shoes 4 and 5 do not run near the ends of the spherical concave portions 9s and 10s on the shaft 1 side, let alone the sliding shoe. It is possible to prevent the situation where the shoes 4 and 5 are bitten and locked, and the sliding shoes 4 and 5 fall off.

Further, the lubricant present in the recesses on the surface of the sprayed coating L1 or the holes formed inside the coating is swash plate 2
Since it is not peeled and removed by sliding contact between the sliding shoes 4 and 5, the lubricating effect can be kept constant for a long period of time, and the durability is excellent.

The present invention is not limited to the above-described embodiments, but can be variously modified within the scope of the claims.

For example, in the above-described embodiment, the variable displacement swash plate type compressor has been described as an example, but the contents of the present application are applicable not only to the variable displacement type compressor but also to the fixed displacement swash plate type compressor. Of course, it can be applied. The piston can also be applied to a so-called double-headed piston having heads on both axial sides of the connecting portion with the swash plate.

Further, in the above-mentioned embodiment, the concave portion 83 formed on the inner peripheral surface of the front housing 20f is
A circular arc concave surface 83a centering on a different central axis is formed so as to face each detent portion 82 of each piston 6, and the circular arc concave surface 83a is formed on the front housing 20f.
It is also possible to form all or part of the inner surface of the cylinder formed over the entire circumference along the inner peripheral surface of, and make the central axis coincide with the central axis of the shaft 1.

Furthermore, in the above-described embodiment, the solid lubricant has been described as an example, but it is needless to say that the lubricant can be applied according to the sliding condition, and the solid lubricant is added to the lubricant. It is also possible to use it. Also,
It is also possible to incorporate a suitable resin as a binder in a solvent in which the solid lubricant is dispersed, and fix it on the surface of the thermal spray coating.

[0052]

As described above, according to the present invention, the following effects can be obtained by the configurations described in the respective claims.

In the structure described in claim 1, the coating formed on the surface of the swash plate is coated and impregnated with a lubricant to improve the lubrication action, while the thermal conductivity of the metal forming the coating is improved. The seizure prevention property can be improved because it is made large to make it difficult to cause a local temperature rise due to frictional heat. Further, since the thermal spray coating having a strong adhesive force is formed with the swash plate, the durability is excellent.

According to the second aspect of the present invention, since the copper alloy having good antifriction property and high thermal conductivity is used as the metal for thermal spraying, the seizure prevention property can be improved.

According to a third aspect of the present invention, an alloy containing copper as a main component and containing tin as a metal for thermal spraying, which has a good antifriction property under high load and high speed rotation and a large thermal conductivity, is used as a metal for thermal spraying. Therefore, the seizure prevention property can be further improved.

According to the fourth aspect of the present invention, the solid lubricant having a layered structure that is easily sheared is applied to the surface of the thermal spray coating to impregnate it to improve the lubrication action. Therefore, the anti-seizure property is further improved. be able to.

According to the fifth aspect of the present invention, the surface of the thermal spray coating is impregnated with molybdenum disulfide, which is a solid lubricant having a layered structure having a low friction coefficient and being easily sheared, to improve the lubricating action. Therefore, the anti-seizure property can be further improved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a variable capacity swash plate compressor according to the present invention.

FIG. 2 is an enlarged explanatory view of a main part of FIG.

FIG. 3 is a schematic cross-sectional view of a conventional variable displacement swash plate compressor.

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is an enlarged explanatory view of a main part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Shaft, 2 ... Swash plate, 2a ... Journal part 2b ... Flat plate part, 3 ... Crank chamber, 4,5 ... Sliding shoe, 4a, 5b ... Circular plane part, 6 ... Piston, 7 ... Cylinder chamber, 9,10 ... Connecting portion, 9s, 10s ... Spherical concave portion, L1 ... Spray coating, L2 ... Lubricating thin film.

Claims (5)

[Claims] 1. A shaft (1) rotatably mounted through a crank chamber (3) and a swash plate (2) arranged in the crank chamber (3) and connected to the shaft (1). ,
A hinge mechanism (K) for transmitting the rotation of the shaft (1) to the swash plate (2) and a sliding mechanism (4, 5) so that the swash plate (2) can slide inside. Cylinder chamber (7) in which the connected portion (9, 10) is formed
A swash plate compressor having a plurality of pistons (6) axially reciprocating in the inside of the swash plate (2),
5) A flat plate portion (2b) slidably contacting and sandwiched is formed, and the flat plate portion (2b) has a sprayed coating (L1) formed by spraying a metal having high thermal conductivity. A swash plate compressor in which the surface of the sprayed coating (L1) is coated and impregnated with a lubricant. 2. The swash plate compressor according to claim 1, wherein the metal is a copper alloy. 3. The swash plate compressor according to claim 2, wherein the copper alloy contains copper as a main component and contains tin. 4. The lubricant according to claim 1, wherein the lubricant is a solid lubricant having a layered structure.
The swash plate compressor according to item. 5. The swash plate compressor according to claim 4, wherein the solid lubricant is molybdenum disulfide.