JP3033341B2 - Swash plate compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type compressor used for a vehicle air conditioner or the like.

[0002]

2. Description of the Related Art A conventional swash plate type compressor is disclosed in
One disclosed in Japanese Patent No. 175,783 is known. In this compressor, as shown in FIG. 3, a cylinder block 82 having a plurality of cylinder bores 81 is arranged at a central portion in a center housing 80, and a front end thereof forms a closed crank chamber 83 to form a front end. The rear end is closed by a rear housing 86 via a valve plate 85. The rear housing 86 is provided with a suction chamber 87 and a discharge chamber 88 that communicate with the cylinder bore 81. A drive shaft 89 is inserted and supported in the center shaft hole of the cylinder block 82, and a rotation support 90 is supported on the drive shaft 89 in a crank chamber 83 so as to be able to rotate synchronously. Rotary support 90
Is connected to a swash plate 93 via a hinge mechanism 91. The hinge mechanism 91 includes a long hole 91a penetrating through the rotation support body 90, and a hinge pin 9 fixed to a swing plate 93a engaged with the long hole 91a and extending from the swash plate 93.
3b. The swash plate 93 has flat surfaces 93c and 93c on the front and back as shown in FIG. 4, and a sleeve 92 is interposed between the swash plate 93 and the drive shaft 89 as shown in FIG. The sleeve 92 is provided so as to be slidable in the axial direction of the drive shaft 89, and maintains a spherical contact with the swash plate 93 on the outer peripheral surface. Thus, the swash plate 93 can be rotated synchronously with the drive shaft 89 and can be displaced at an inclination angle. The swash plate 93 has a single-headed piston 94 fitted in each cylinder bore 81.
Are moored via a pair of shoes 95, 95. Each shoe 95 is, as shown in FIG.
3c, the hemispherical portion 95b is bulged behind the flat surface 95a. As shown in FIG. 3, the hemispherical portion 95b of each shoe 95 is engaged with a spherical seat 94a, 94a formed in the neck of the piston 94. The cylinder block 82 is provided with a communication hole 96 for communicating the crank chamber 83 with the suction chamber 87. The communication hole 96 is provided with a control valve 9 for controlling the pressure in the crank chamber 83.
7 is opened and closed.

In this compressor, when the swash plate 93 rotates with the driving of the drive shaft 89, the spherical seat 94a of the piston 94
As shown in FIG. 4, each shoe 95 having a hemispherical portion 95b engaged with the flat surface 95c of the swash plate 93
Slides in an elliptical orbit according to the inclination angle of the swash plate 93. The sliding of the elliptical orbit involves relative displacement in the circumferential direction (arrow A),
This is performed by the relative displacement of the swash plate 93 in the radial direction (arrow C). Also, at this time, each shoe 95 is
And the spherical seat 94a swing in the radial direction (arrow B). In this way, only the swinging motion corresponding to the tilt angle of the swash plate 93 is converted into the reciprocating motion of each piston 94 in the cylinder bore 81. Thereby, as shown in FIG. 3, the refrigerant gas is sucked into the cylinder bore 81 from the suction chamber 87, and is discharged to the discharge chamber 88 after being compressed.

The compression capacity of the refrigerant gas discharged into the discharge chamber 88 is controlled by adjusting the pressure in the crank chamber 83 by the control valve 97. That is, if the pressure in the crank chamber 83 communicates with the suction chamber 87 by the control valve 97 opening the communication hole 96, the back pressure acting on the piston 94 decreases, and the inclination angle of the swash plate 93 increases. .
That is, the hinge pin 93b of the hinge mechanism 91 is
The position of the swash plate 93 moves to a position farther from the drive shaft 89 within a, and the sleeve 92 moves forward, and the swash plate 93 rotates in the vertical direction along the outer peripheral surface of the sleeve 92. At this time, each shoe 95
Changes the elliptical trajectory in a direction to extend its major axis by expanding the relative displacement (arrow C). Thereby, the piston 9
Stroke 4 is extended and the compression capacity is increased.

Conversely, if the pressure in the crank chamber 83 is increased by blow-by gas due to the control valve 97 closing the communication hole 96, the back pressure acting on the piston 94 is increased, and the inclination angle of the swash plate 93 is reduced. Become smaller. That is, the hinge pin 93b of the hinge mechanism 91 is inserted into the drive shaft 8 within the elongated hole 91a.
9, the sleeve 92 retreats, and the swash plate 93 rotates in the upright direction along the outer peripheral surface of the sleeve 92. At this time, each shoe 95 changes the elliptical trajectory in a direction to shorten its major axis by reducing the relative displacement (arrow C). As a result, the stroke of the piston 94 is shortened, and the compression capacity is reduced.

[0006]

However, each shoe 95 of the compressor is displaced in the radial direction of the swash plate 93 between the piston 94 and the hemispherical portion 95b and the spherical seat 94a between the pistons 94. Is restricted, but the swash plate 93 is inclined.
Since the plane 95a is only in contact with the plane 93c, the displacement in the radial direction is allowed. Therefore, each piston 94 is connected to each swash plate 9 via each shoe 95.
The compressive load acting on 3 acts as a radial force (side force) according to the inclination angle of the swash plate 93 in addition to the axial force. In particular, in this single-headed piston type compressor, the piston 94 is provided on one side of the swash plate 93, and both ends of the piston are not guided in the cylinder bore 81 unlike the double-headed piston type. The force tilts radially in the cylinder bore 81 in the cylinder bore 81 to cause a partial contact, causing uneven wear between the piston 94 and the cylinder bore 81.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a single-head piston type swash plate type compressor in which the tilting of the piston is suppressed to effectively prevent uneven wear due to one-sided contact between the piston and the cylinder bore. It is.

[0008]

SUMMARY OF THE INVENTION A swash plate type compressor according to the present invention comprises a cylinder block having a plurality of bores which support a drive shaft and are arranged in parallel around the drive shaft, and a crank which is connected to the cylinder block. A housing forming a chamber, a swash plate accommodated in the crank chamber and co-operating with a drive shaft, and a single-head type moored to the swash plate via shoes supported by a spherical seat and linearly moving in the bore. A swash plate compressor having a piston, wherein the center of the spherical seat of the piston is unevenly distributed in the centrifugal direction of the swash plate with respect to the center of the bore.

[0009]

In the swash plate type compressor, when the swash plate rotates with the driving of the drive shaft, the oscillating motion corresponding to the inclination angle of the swash plate is converted into the reciprocating motion of the piston via the shoe. At this time,
Since the shoe is allowed to be displaced in the radial direction of the swash plate between the shoe and the swash plate, the shoe tries to tilt the piston radially outward in the radial direction according to the inclination angle of the swash plate. Component force is transmitted from the swash plate to the piston via the shoe.

[0010] In the swash plate compressor of the present invention, the center of the spherical seat of the piston supporting the shoe is eccentrically located in the centrifugal direction of the swash plate with respect to the center of the bore. For this reason, the horizontal component of the force by which the swash plate presses the piston via the shoe acts on the centrifugal side of the axis of the piston reciprocating in the bore. A rotational moment acts to tilt inward in the direction. At the time of reciprocation of the piston, the rotational moment that causes the piston to tilt inward in the radial direction always opposes the component force that causes the piston to tilt outward in the radial direction. Tilt of the piston outward in the radial direction can be suppressed. For this reason, even with a single-headed piston,
One-sided contact between the piston and cylinder bore is unlikely to occur.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. This compressor, as shown in FIG.
A cylinder block 1 having a plurality of cylinder bores 1a is arranged at a central portion, a front end of the cylinder block 1a forms a closed crank chamber 2a and is closed by a front housing 2, and a rear end of the cylinder block 1 It is closed by the housing 3. The rear housing 3 is provided with a suction chamber 3a and a discharge chamber 3b communicating with the cylinder bore 1a. A drive shaft 4 is inserted and supported in the center shaft hole of the cylinder block 1. A rotary support 5 is supported on the drive shaft 4 in the crank chamber 2a so as to be able to rotate synchronously. Note that the plurality of cylinder bores 1a are
Are arranged in parallel around. A rotary drive 11 is supported on the rotary support 5 via a hinge mechanism K. In the hinge mechanism K, a mounting hole 6a is provided through a support arm 6 projecting rearward from the rotary support 5, and the mounting hole 6a
The race 8 is fixed to the
Are swingably equipped. Guide hole 9a in sphere 9
And a guide pin 10 is provided in the guide hole 9a.
Are reciprocally supported. In addition, the rotation driving body 11
A mounting hole 11a is also provided through the mounting hole 11a.
The guide pin 10 is press-fitted.

A swash plate 15 is fixed to the rear of the rotary driving body 11 by a tightening ring 16. On this swash plate 15,
A single-headed piston 19 reciprocally fitted into each cylinder bore 1a is moored via a pair of shoes 17,17. The single-headed piston 19 has a neck portion 19a and a head portion 19b extending from the neck portion 19a in the moving direction.
Are engaged. And the spherical seat 19c of the piston 19
Of the swash plate 1 with respect to the center C of the cylinder bore 1a.
In the centrifugal direction of 5 is provided to unevenly distributed only L _x (see FIG. 2).

The rotary drive 11 has a sleeve 13 interposed between the rotary drive 11 and the drive shaft 4. The sleeve 13 is slidably provided in the axial direction of the drive shaft 4 via springs 20 and 21. A sleeve pin (not shown) is provided on the outer surface of the sleeve 13 in a direction perpendicular to the axis. This sleeve pin is engaged with a mounting hole (not shown) of the rotary driving body 11. Thus, the swash plate 15 can be rotated synchronously with the drive shaft 4 via the rotary support 5 and the rotary drive 11, and can be displaced at an inclined angle via the hinge mechanism K and the sleeve 13.

Further, the rear housing 3 is provided with a control valve 22 for adjusting the pressure of the crank chamber 2a.
In this compressor, similarly to the conventional compressor, when the swash plate 15 rotates in accordance with the driving of the drive shaft 4, each piston 19 reciprocates in the cylinder bore 1a, thereby moving the cylinder bore 1a from the suction chamber 3a. The refrigerant gas is sucked into the inside, and is discharged to the discharge chamber 3b after being compressed.

Then, as shown in FIG. 1, the compression capacity of the refrigerant gas discharged into the discharge chamber 3b is controlled by adjusting the pressure in the crank chamber 2a by the control valve 22. That is, for example, when the control valve 22 connects the crank chamber 2a and the suction chamber 3a, the back pressure acting on the piston 19 decreases, and the inclination angle of the swash plate 15 increases. That is, when the sphere 9 slides with the race 8, the guide pin 10 swings forward, the rotary driving body 11 swings rightward in FIG.
The guide pin 10 slides in a direction to enter the guide hole 9a. And the swash plate 15 is the rotary driving body 1
1. Swinging backward through the sleeve 13, the inclination angle increases. For this reason, the stroke of the piston 19 is extended and the compression capacity is increased.

Conversely, if the control valve 22 closes the communication between the crank chamber 2a and the suction chamber 3a, the pressure in the crank chamber 2a is increased by the blow-by gas, and the back pressure acting on the piston 19 is increased. The inclination angle of the plate 15 becomes smaller. That is, when the sphere 9 slides with the race 8, the guide pin 10 swings rearward, the rotary driving body 11 swings leftward in FIG. 1 around the sleeve pin, and the sleeve 13 resists the spring 20. Then, the guide pin 10 slides in a direction in which the guide pin 10 comes out of the guide hole 9a. Then, the swash plate 15 swings forward through the rotary driving body 11 and the sleeve 13, and the inclination angle becomes small. For this reason, the piston 19
Is reduced, and the compression capacity is reduced.

The rotation of the swash plate 15 causes the swash plate 15 to rotate.
When the oscillating motion corresponding to the inclination angle of the swash plate 15 is converted into the reciprocating motion of the piston 19 via the shoes 17, 17, the radial displacement of the swash plate 15 between the shoe 17 and the swash plate 15 is allowed. Therefore, a radial side force corresponding to the inclination angle of the swash plate 15, that is, a component force for tilting the piston 19 radially outward is transmitted from the swash plate to the piston via the shoe.

[0018] In the compressor of this embodiment, the center O of the spherical seat 19c of the piston 19 which supports the shoe 17 are unevenly distributed in the centrifugal direction of the swash plate 15 with respect to the center C of the cylinder bore 1a by L _X. For this reason, as shown in FIG.
The horizontal component F of the force pressing the piston 19 via the shoe 17 is the piston 1 reciprocating in the cylinder bore 1a.
9 acts more distally than the axis of
A rotation moment (M = FL _× L) acting to tilt the head 19b side inward in the radial direction acts on itself. When the piston 19 reciprocates, a rotational moment for tilting the piston 19 inward in the radial direction is always generated by the piston 19.
Is opposed to the above-described component force that causes the piston 19 to tilt outward in the radial direction, so that the piston 19 can be suppressed from tilting outward in the radial direction due to the side force. For this reason, even if it is a single head type piston, it is difficult to cause a partial contact between the piston 19 and the cylinder bore 1a, and it is possible to effectively prevent uneven wear.

The amount L _X by which the center O of the spherical seat 19c is displaced in the centrifugal direction of the swash plate 15 with respect to the center C of the cylinder bore 1a is calculated as follows from a dynamic calculation of the load acting on the piston 19. Can be set to FIG.
As shown in, and F the horizontal component of the force shoe 17 presses the piston 19 as described above, the radial side force which can case is tilted and R _B of the piston 19 radially outward. Also when the piston 19 is tilted radially outward by the side force R _B, the piston 19
The reaction force from the cylinder bore acting on the cylinder bore is defined as _RA . Further, the inclination angle of the swash plate 15 is θ, the distance from the center O of the spherical seat 19c to the end face of the head 19b on the neck 19a side is L ₂ , and the axial length of the head 19b is L ₃ .

At this time, the following equation (1) is derived from the balance of the moment at the intersection A between the end face of the head 19b on the neck 19a side and the axis of the piston 19. F · L _x −Ftan θ · L ₂ + R _A · L ₃ = 0 (1) From the above equation (1), R _A = F (tan θ · L ₂ −L _x ) / L ₃ (3) Here, in the above (3), is set so that _{tanθ · L 2 -L x <0} , when the piston 19 is tilted radially outward by a side force (R _B), the piston 19 The reaction force (R _A ) from the acting cylinder bore becomes negative, and the piston 1 caused by the side force (R _B )
9 can be restrained from tilting outward in the radial direction.

[0021]

As described above in detail, in the compressor according to the present invention, the center of the spherical seat of the piston supporting the shoe is deviated in the centrifugal direction of the swash plate with respect to the center of the bore. In this manner, it is possible to effectively prevent uneven wear of the piston and the cylinder bore due to the side force received by the piston.

Therefore, when this compressor is employed in, for example, a vehicle air conditioner, excellent durability can be exhibited.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a compressor according to an embodiment.

FIG. 2 is a side view of a main part of the compressor of the embodiment.

FIG. 3 is a longitudinal sectional view of a conventional compressor.

FIG. 4 is an exploded perspective view of a main part of a conventional compressor.

[Explanation of symbols]

1: Cylinder block 2, 3: Housing
2a: Crank chamber 1a: Cylinder bore 4: Drive shaft
15 ... Swash plate 17 ... Shoe 19 ... Piston
19c ... Spherical seat

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kenji Takenaka 2-1-1 Toyota-cho, Kariya-shi, Aichi Pref. Inside Toyota Industries Corporation (56) Reference Reference JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04B 27/08

Claims (1)

(57) [Claims] 1. A cylinder block having a plurality of bores which support a drive shaft and are arranged in parallel around the drive shaft, a housing which is combined with the cylinder block to form a crank chamber, and which is housed in the crank chamber. A swash plate cooperating with a drive shaft, and a single-headed piston moored to the swash plate via a shoe supported by a spherical seat and linearly moving in the bore. Wherein the center of the spherical seat is unevenly distributed in the centrifugal direction of the swash plate with respect to the center of the bore.