JP2002081372A - Variable displacement swash plate type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable displacement swash plate type compressor capable of accurately carrying out a capacity control. SOLUTION: In the variable displacement mono-head piston swash plate type compressor in which a mono-head piston 16 is made of aluminum, a swash plate 11 is formed by an iron system material and a shoe 17 is formed by an aluminum system material. There is no fear that a seizure caused by a sliding of the mono-head piston 16 and the shoe 17 is generated by forming a coating film on a slide surface of the shoe 17 with the mono-head piston 16. Since the swash plate 11 is formed by the iron system material, a centrifugal force applied to the swash plate 11 is increased as compared with a case where the swash plate 11 is formed by the aluminum system material. The centrifugal force is resistant to a reciprocation motion inertia force caused by a weight of the mono-head piston applied to a direction increasing an inclination angle of the swash plate 11 and it is prevented that the inclination angle of the swash plate 11 is increased. Thereby, a discharge quantity of the compressor is maintained to a set capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable capacity swash plate compressor used for air conditioning of a vehicle.

[0002]

2. Description of the Related Art Conventional swash plate compressors of this type include:
For example, a configuration as disclosed in Japanese Utility Model Publication No. Sho 61-43981 is known.

In this conventional configuration, a pair of shoes are formed into a shape that forms a part of a sphere, and a piston is engaged with a peripheral edge of a swash plate via the shoes. The piston reciprocates linearly back and forth with the rotation of the swash plate. In this configuration, the swash plate and the piston are formed of an aluminum-based material, and the shoe is formed of an iron-based material.

[0004]

When the swash plate is rotated by the swash plate compressor, a centrifugal force due to its own weight and a reciprocating inertia force due to the weight of the piston act on the swash plate. In addition, a suction reaction force and a compression reaction force in the suction and compression strokes act on the swash plate. However, these two forces cancel each other out, and thus do not matter here. The centrifugal force acts on the swash plate to decrease the inclination, and the inertial force acts on the swash plate to increase the inclination. Normally, the inertial force exerts a greater effect on the swash plate, and the inclination of the swash plate increases, and the capacity of the compressor tends to increase beyond the set capacity of the compressor. In particular, in the case of a variable displacement compressor, since the discharge flow rate increases at high speed rotation, it is desirable to perform control to reduce the inclination angle of the swash plate so as to reduce the capacity. Since the inertia force of the compressor increases, the compressor may be operated with an unnecessarily large capacity.

The present invention has been made in view of the problems existing in the above prior art, and an object thereof is to form a swash plate with a material having a higher specific gravity than a piston to increase the centrifugal force acting on the swash plate. Accordingly, an object of the present invention is to provide a variable displacement swash plate type compressor capable of performing displacement control more accurately.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention is configured as follows. That is, according to the first aspect of the invention, a plurality of cylinder bores located between the crank chamber, the suction chamber, and the discharge chamber are arranged around the rotation axis, and the single-headed piston is accommodated in the cylinder bore so as to be able to reciprocate linearly. In addition, the swash plate is tiltably supported on the rotating shaft in the crank chamber, and the single-headed piston is connected to the swash plate through a pair of shoes formed in a shape forming a part of a sphere at the neck of the piston end. In a variable displacement swash plate type compressor which engages with a peripheral portion and further changes a piston stroke by controlling a pressure in a crank chamber, the single-headed piston and the shoe are each formed of an aluminum-based material, and A coating is applied to the sliding surface of the piston with the shoe or the sliding surface of the shoe with the single-headed piston, and the swash plate is attached to the single-headed piston. It is characterized by formed by a material having large specific gravity than ton and shoe.

[0007] The invention described in claim 2 is the first invention.
The swash plate is formed of an iron-based material or a copper-based material. (Operation) In the variable displacement swash plate type compressor of the present invention configured as described above,
Since the specific gravity of the swash plate is larger than the specific gravity of the single-headed piston, the effect of the centrifugal force acting on the swash plate also increases. Thereby, the centrifugal force opposes the inertial force. Therefore, an appropriate piston stroke can be obtained according to the pressure in the crank chamber.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the present invention is embodied in a variable displacement swash plate type compressor having a single piston will be described below with reference to FIG.

As shown in FIG. 1, a front housing 2 is joined to a front end of a cylinder block 1 which is a part of a housing of the entire compressor. A rear housing 3 is joined and fixed to the rear end of the cylinder block 1 via a valve plate 4. A bearing 7 is provided in the front housing 2.
A disk-shaped rotary support 8 is supported via the rotary support 8, and a rotary shaft 9 is fixed to the rotary support 8. Rotating shaft 9
Is supported by the cylinder block 1 via a bearing 23.

A swash plate support 10 having a spherical shape is supported on the rotating shaft 9 so as to be slidable in the axial direction.
The swash plate 11 is supported to be tiltable. A connecting piece 12 is fixed to the swash plate 11, and a guide pin 13 is fixed to the connecting piece 12. A support arm 8a protrudes from the rotating support 8, and a support pin 14 is rotatably supported through the support arm 8a. Guide pin 13
Is slidably fitted into the end of the support pin 14. Support pin 14 and guide pin 13 on support arm 8a
The swash plate 11 is integrally rotatable with the rotation shaft 9 by coordination with the above.

The maximum inclination angle of the swash plate 11 is regulated by the contact between the inclination regulating protrusion 8 b of the rotary support 8 and the swash plate 11.
A minimum inclination restriction ring 15 is fixed on the rotating shaft 9, and the minimum inclination of the swash plate 11 is restricted by the contact between the minimum inclination restriction ring 15 and the swash plate support 10.

A plurality of cylinder bores 1a are provided in the cylinder block 1 so as to be located between the crank chamber 2a and a suction chamber 3a and a discharge chamber 3b, which will be described later, and these are arranged around a rotation shaft 9. . A single-headed piston 16 is housed in the cylinder bore 1a. A pair of shoes 17 each having a shape that forms a part of a sphere are fitted into the neck portion 16a of the single-headed piston 16. The peripheral portion of the swash plate 11 extends between the two shoes 17. When the swash plate 11 is rotated, the rotation of the swash plate 11 is
Is converted into a reciprocating linear motion of the one-headed piston 16 through
The single-headed piston 16 moves back and forth in the cylinder bore 1a.
In this configuration, the single-headed piston 16 is formed of an aluminum-based material. The pair of shoes 17 are also formed of the same aluminum-based material as the single-headed piston 16 and
1 is made of an iron-based material. In addition, a coating is applied on the sliding surface of the shoe 17 with the single-headed piston 16 to prevent the shoe 17 from burning with the single-ended piston 16. Examples of the type of coating include nickel-boron plating and welding of a copper-based metal by plasma spraying.

In the rear housing 3, a suction chamber 3a and a discharge chamber 3b are defined. A suction port 4a and a discharge port 4b are formed on the valve plate 4. A suction valve 5a and a discharge valve 5b are provided on the valve plate 4.
Are formed. The refrigerant gas in the suction chamber 3a moves the suction valve 5a from the suction port 4a by the operation of the single-headed piston 16 to the left in the drawing, and flows into the cylinder bore 1a. The refrigerant gas flowing into the cylinder bore 1a is discharged to the discharge chamber 3b by pushing the discharge valve 5b from the discharge port 4b by the operation of the single-headed piston 16 to the right in the drawing.

The stroke of the single head piston 16 changes according to the pressure difference between the pressure in the crank chamber 2a and the suction pressure in the cylinder bore 1a. That is, the inclination angle of the swash plate 11 that affects the compression capacity changes. The pressure in the crank chamber 2a is controlled by a control valve 18 attached to the rear housing 3.

The displacement control valve 18 has a discharge pressure introduction port 1
9a, a suction pressure introduction port 19b and a control port 19c are provided. The discharge pressure introduction port 19a communicates with the discharge chamber 3b via the discharge pressure introduction passage 20. The suction pressure introduction port 19b is connected to the suction chamber 3 through the suction pressure introduction passage 21.
a, and the control port 19c communicates with the crank chamber 2a via the control passage 22. Then, the capacity control valve 18 detects the suction refrigerant gas pressure introduced from the suction pressure introduction port 19b, and supplies the control port 19 with a required amount of the high-pressure discharge refrigerant gas introduced from the discharge pressure introduction port 19a.
c, the swash plate 11 is guided to the crank chamber 2a through the control passage 22 so that the compressor can be operated with an appropriate capacity.
Is installed at an appropriate angle.

In this manner, the inclination of the swash plate 11 is determined by the maximum inclination position at which the swash plate 11 comes into contact with the inclination restricting projection 8b and the swash plate support 1.
0 is restricted between the minimum inclination position and the minimum inclination position where the ring contacts the minimum inclination restriction ring 15, and the discharge capacity is controlled within this inclination range.

Next, the operation of the variable displacement swash plate type compressor constructed as described above will be described. With the reciprocating movement of the single-headed piston 16, the refrigerant gas in the suction chamber 3a flows into the suction port 4a.
Flows into the cylinder bore 1a from the
After receiving the compression action, the discharge chamber 4
b. The reciprocating stroke of the single-headed piston 16 changes according to the tilt angle of the swash plate 11, and the tilt angle of the swash plate 11 is controlled by a displacement control valve 18.

The displacement control valve 18 controls the displacement as follows. When the cooling load is large, the suction refrigerant gas pressure increases, and the supply of the discharge refrigerant gas to the crank chamber 2a is cut off by the capacity control valve 18.
The pressure in a decreases, and the inclination angle of the swash plate 11 increases. Accordingly, the stroke of the single-headed piston 16 is increased, and a large-capacity operation is performed. On the other hand, when the cooling load is small, the suction refrigerant gas pressure decreases, and a large amount of discharge refrigerant gas is supplied to the crank chamber 2a by the capacity control valve 18. Therefore, the pressure in the crank chamber 2a increases, and the pressure of the swash plate 11 increases. The tilt decreases. Therefore, the stroke of the single-headed piston 16 is reduced, and the small-capacity operation is performed.

When the compressor is operated, the swash plate 11 is subjected to centrifugal force due to its own weight, which acts to reduce the inclination, and reciprocating inertial force, due to the weight of the piston, which acts to increase the inclination. When the swash plate is made of the same aluminum-based material as the piston as in the conventional case, the inertia force exerts a greater effect on the swash plate because the specific gravity of the swash plate is small.
As described above, the effect is particularly remarkable when the engine rotates at high speed. In other words, during high-speed rotation of the engine, during small-capacity operation in which the inclination angle of the swash plate 11 is small, the inclination angle of the swash plate increases, and the capacity becomes larger than the set capacity. Inconvenience occurs. On the other hand, in this embodiment, since the swash plate 11 is formed of an iron-based material, the specific gravity is larger than that of the single-headed piston 16, and the centrifugal force due to the weight of the swash plate 11 increases compared to the conventional one. In addition, the reciprocating inertial force due to the weight of the single head piston can be countered. Therefore, the compressor is controlled by the capacity control valve 18.
It is operated at a capacity controlled by

In this embodiment, since the swash plate 11 is formed of an iron-based material, accurate displacement control by the displacement control valve 18 is possible even at the time of high-speed rotation of the engine where the effect of inertia force is remarkable. is there. The shoe 17 is formed of the same aluminum-based material as the single-headed piston 16. However, a coating is formed on the sliding surface of the shoe 17 with the single-ended piston 16 to form a coating layer. There is no fear of burning due to sliding of the same material between the shoe 16 and the shoe 17. Further, the swash plate 11 is formed of an iron-based material, and the iron-based material is less deformed and deformed by processing than the aluminum-based material.
Has the advantage of being easy to process.

In this embodiment, since the shoe 17 is formed of an aluminum-based material, the compressor is lighter in weight than the case where the shoe 17 is formed of an iron-based material. In this embodiment, the coating may be applied to the sliding surface of the single-headed piston 16 with the shoe 17 instead of the shoe 17.

The present invention is not limited to the configuration of the above-described embodiment, but may be embodied by arbitrarily changing the configuration of each unit without departing from the spirit of the present invention. For example, the swash plate 11 may be formed of another material such as a copper-based material having a higher specific gravity than the single-headed piston 16 instead of the iron-based material.

[0023]

As described above in detail, according to the present invention, there is an excellent effect that the discharge displacement of the variable displacement swash plate type compressor can be maintained at the set displacement and displacement control can be accurately performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an entire compressor according to an embodiment of the present invention.

[Explanation of symbols]

11: swash plate, 16: single-headed piston, 17: shoe, 18
... Capacity control valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keiichi Kato 2-1-1 Toyota-cho, Kariya-shi, Aichi Pref. Inside Toyota Industries Corporation (72) Inventor Osamu Hiramatsu 2-1-1 Toyota-cho, Kariya-shi, Aichi Pref. F term in Toyota Industries Corporation (reference) 3H003 AA03 AB07 AC03 AD01 CB00 3H076 AA06 BB32 BB43 BB50 CC12 CC20 CC31 CC33 CC39 CC99

Claims (2)

[Claims] A plurality of cylinder bores located between a crank chamber, a suction chamber, and a discharge chamber are arranged around a rotation axis, and a single-headed piston is accommodated in the cylinder bore so as to be capable of reciprocating linear movement. While supporting the swash plate tiltably on the shaft, at the neck of the piston end,
A single-headed piston is engaged with the peripheral edge of the swash plate via a pair of shoes formed in a shape that forms part of a sphere, and the piston stroke is changed by controlling the pressure in the crank chamber. In the capacity swash plate compressor, the single-headed piston and the shoe are each formed of an aluminum-based material, and a coating is formed on a sliding surface of the single-headed piston with the shoe or on a sliding surface of the shoe with the single-ended piston. Wherein the swash plate is formed of a material having a higher specific gravity than the single-headed piston and the shoe. 2. The variable displacement swash plate type compressor according to claim 1, wherein the swash plate is formed of an iron-based material or a copper-based material.