JPH0458076A - Swash plate type compressor - Google Patents

Abstract

PURPOSE:To enhance seizure resistance between each piston and each cylinder by forming each recessed section opening to the side of a valve plate at each section corresponding to a straight line which connects the center of a driving shaft to the center of, at least, each cylinder bore in the circumferential surface of a shaft hole in a cylinder block in order that a bearing is to be coupled in. CONSTITUTION:Each shaft hole 1a and 2a in which each radial bearing 9 is coupled, is formed with each recessed section 26 a part of which is opened to the side of each valve plate 3 and 4 at each section corresponding to a straight line which connects the center of a driving shaft 10 to the center of, at least, each cylinder bore 9 in its circumferential surface. This thereby does not allows any force acting onto each radial bearing 9 to be applied toward the axial center of each cylinder bore 12 at its end section, which is in a compression stroke. This thereby restrains each cylinder bore 12 from being elastically deformed, and this also allows each piston 13 to be smoothly moved within each cylinder bore 12, thereby enhancing seizure resistance between each piston 13 and each cylinder bore 12.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has a cylinder bore in which a piston that performs a compression action on the front and rear sides is accommodated in a reciprocating manner, and the piston is rotatably supported by a cylinder block. The present invention relates to a swash plate compressor that is reciprocally driven via a swash plate mounted on a drive shaft, and more particularly to a swash plate compressor with improved piston sliding properties during compressor operation.

[Prior Art] As shown in FIG. 9, this type of swash plate compressor has cylinder blocks 1. Both ends of the housing 2 are closed by front and rear housings 5 and 6 via valve plates 3 and 4, respectively, and are connected and fixed by a plurality of bolts 7.

A swash plate chamber 8 is formed at the joint portion of the cylinder blocks 1 and 2, and both cylinder blocks l are formed in the swash plate chamber 8.

A swash plate 11 is housed in shaft holes 1a and 2a extending through the center of the drive shaft 2, and is fitted onto a drive shaft 10 which is rotatably supported via a radial bearing 9. A plurality of pairs of cylinder bores 12 are provided in the cylinder blocks 1 and 2, and a drive shaft 1
0 and at radial positions centered on the drive shaft 10, and a double-headed piston 13 is slidably accommodated in each cylinder bore 12. Each piston 13 has a shoe 14
Suction chambers 15.1 formed in both housings 5 and 6 are moored to swash plate II via
6 to the compression chambers Pf and Pr via the suction valve mechanism 17.18.
The refrigerant gas is sucked into the chamber, and the compressed refrigerant gas is discharged to the discharge chamber 21, 22 via the discharge valve mechanism 19.20. The swash plate chamber 8 is communicated with a suction chamber 15.16 via a suction passage 23.24 formed in the cylinder block 1.2, and the air is introduced into the swash plate chamber 8 through a suction port 25 connected to an external cooling circuit (not shown). The refrigerant gas passes through the suction passage 23.24 and enters the suction chamber 15.16.
is being supplied to.

When the piston 13 performs a compression operation as the drive shaft 10 rotates, the pressures within the compression chambers Pf and Pr act on the piston 13 in opposite directions along its axial direction. Since one of the front and rear compression chambers Pf and Pr is in the compression stroke and the other is in the suction stroke, piston 3 is the difference between the pressure Pd in the compression chamber in the compression stroke and the pressure Ps in the compression chamber in the suction stroke. A force having a magnitude of is applied in the direction opposite to the direction of movement of the piston 13. Due to the force acting on the piston 13, the swash plate 11 receives a moment M as shown in FIG. moment M
acts. Therefore, the same moment M is applied to the drive shaft 10.
acts, and forces Bf and Br are applied from the radial bearing link 9 to the cylinder block 1.2 supporting the drive shaft 10 via the radial bearing 9.

[Problems to be Solved by the Invention] The forces Bf and Br that act on the cylinder blocks 1 and 2 via the radial bearings 9 are in the direction connecting the center of the drive shaft lO and the center of the cylinder bore 12, and Acts closer to the valve plate. Therefore,
In the state shown in FIG. 9, as shown in FIG. 10, the cylinder bore I2 of Nα3 among the front cylinder bores 12 is
Elastic deformation occurs due to the action of force Bf. On the other hand, force Br acts on the cylinder block 2 on the rear side symmetrically with the front side, but the direction is No.
1 and Nα5 toward the partition wall between the cylinder bores 12, and no deformation of the cylinder bore 12 occurs on the rear side. Assuming that the direction of rotation of the swash plate II is clockwise in FIG.
2 is Nα4, Nα5, No, l.

Elastic deformation occurs sequentially in the order of Nα2. Further, on the rear side, similar elastic deformation occurs in the cylinder bore 12 which is in the compression stroke.

When the piston 13 moves through the elastically deformed portion of the cylinder bore 12, the piston 13 moves to expand the deformed portion of the cylinder bore 12.
The friction between the circumferential surface of cylinder 3 and the cylinder bore 13 becomes large, and seizure is likely to occur between the two. Furthermore, in order to reduce the weight of compressors in recent years, the housing, cylinder block, piston, etc. are made of aluminum alloy, and in order to prevent seizure of the piston 13 and cylinder bore 12 due to adhesion of similar metals, the surface of the piston 13 is coated with fluorine. Some are coated with resin. In this case, the piston 13
When the cylinder moves through the elastically deformed portion of the cylinder bore 12, there is a problem that the coating peels off, reducing sealing performance and making seizure more likely.

The present invention has been made in view of the above problems, and includes:
The purpose is to provide a swash plate compressor that can suppress the elastic deformation of the cylinder bore during the compression stroke, improve the slidability of the piston, and improve the seizure resistance between the piston and the cylinder bore.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a cylinder block having front and rear housings joined to both front and rear ends thereof, a swash plate chamber, and a cylinder block that faces the front and rear sides of the swash plate chamber. A cylinder bore is formed, and a piston that performs a compression action on the front and rear sides is reciprocatably accommodated in the cylinder bore, and the piston is mounted on a drive shaft that is rotatably supported by a cylinder block. In a swash plate type compressor that reciprocates via a swash plate, connecting at least the center of the cylinder bore and the center of the drive shaft on the circumferential surface of a shaft hole formed in the cylinder block for fitting a bearing that supports the drive shaft. A recess with one end opening toward the valve plate was formed in a portion corresponding to the straight line.

[Operation] When the piston reciprocates within the cylinder bore and compresses the refrigerant gas due to the operation of the compressor, a moment is generated in the swash plate whose rotation center is an axis that passes through the center of oscillation of the swash plate and is orthogonal to the drive shaft. is added. This moment also acts on the drive shaft, and a force based on this moment acts via the radial bearing in a straight line connecting the center of the cylinder bore in the compression stroke and the center of the drive shaft. The shaft hole into which the radial bearing is fitted has a recess formed on its peripheral surface (corresponding to the straight line connecting the center of the cylinder bore and the center of the drive shaft) with one end opening toward the valve plate. Therefore, the force acting on the radial bearing does not act toward the axis at the end of the cylinder bore during the compression stroke.

Therefore, elastic deformation of the cylinder bore is suppressed, the movement of the piston within the cylinder bore becomes smooth, and the seizure resistance between the piston and the cylinder bore is improved.

[Example 1] A first example embodying the present invention will be described below with reference to FIGS. 1 to 6. The compressor of this embodiment is basically the same as the conventional device shown in FIG. 9, and the same parts are given the same reference numerals and detailed explanation will be omitted.

As shown in Figures 1 and 2, on the circumferential surfaces of the shaft holes 1a and 2a formed in both cylinder blocks 1. A long annular recess 26 is formed with one end opening toward the valve plates 3 and 4. That is, both radial bearings 9 are in contact with the circumferential wall of the cylinder bore 12 on the inner side of the open end of the cylinder bore 12.

Next, the operation of the compressor configured as described above will be explained.

Now, when the swash plate 11 is rotated by the rotation of the drive shaft 10, each piston 13 is reciprocated in the left-right direction in FIG. 1 within the cylinder bore I2, and refrigerant gas is sucked, compressed, and discharged. During the compression operation of the piston 13, a moment M shown in FIG. 1 acts on the swash plate 11, and the moment M
Based on this, a force Bf is applied from the radial bearing 9 supporting the drive shaft 10 to the front cylinder block 1 toward the center of the cylinder bore 12 during the transition from the compression stroke to the discharge stroke, and the rear cylinder block 2 A force BR in the opposite direction to the force Bf acts on the force Bf.

A shaft hole 1a into which a radial bearing 9 is fitted.

2a has an annular recess 26 that opens toward the valve plates 3 and 4, so a force Bf acts on the cylinder blocks 1 and 2 from the radial bearing 9.

Br acts on the cylinder blocks 1 and 2 at a portion inside the opening end of the cylinder bore 12 near the valve plates 3 and 4.

The action of the force Bf on the cylinder bore 12 can be approximated when a load is applied to the cylinder on its generatrix. As shown in FIGS. 3 and 4, when a point load BL acts on the generatrix of the cylinder 27, the amount of deformation H of the cylinder 27 is
As shown in the figure, the closer the point load BL is to the end surface of the cylinder 27, the larger the point load BL becomes. That is, when a load of the same magnitude is applied, the amount of deformation is reduced by setting the load application position to a position away from the end of the cylinder 27.

In a conventional swash plate compressor, the radial bearing 9 that supports the drive shaft 10 is fitted into the cylinder block 1 on the end face side of the cylinder bore 12 near the valve plate 3. The force Bf that acts on the cylinder block l acts on the cylinder bore 12 near its end face, and the amount of deformation of the cylinder bore 12 increases. On the other hand, in this embodiment, as described above, the force Bf acts on the cylinder block l only on the inner side of the open end of the cylinder bore 12, so that the amount of deformation of the cylinder bore 12 is reduced as shown in FIG. In addition, the end surfaces of the cylinder blocks 1 and 2 are pressed against the valve plates 3 and 4, and when force Bf acts on the end surface of the cylinder bore 12, the force Bf overcomes the pressing force and deforms from the end surface side. When Bf acts at a position away from the end face, this pressure contact force prevents deformation of the end face side of the cylinder bore 12, and the amount of deformation becomes smaller. In addition, it is desirable that the depth of the recess 26 in this embodiment is 1/3 or more of the length of the bearing 9.

[Example 2] Next, a second embodiment will be explained according to FIGS. 7 and 8.

In this embodiment, a recess 26 formed on the circumferential surface of each shaft hole 1a
The shape is different from that of the previous embodiment. Note that since the front side and the rear side have the same configuration, only the front side will be explained. As shown in FIG. 7, the recesses 26 are cut in the same number of layers as the cylinder bore 12, and the center of the shaft hole 1a and the cylinder bore 1
The shaft hole 1a is located at a position corresponding to the straight line connecting the center of 2.
It is formed longer than the length of the radial bearing 9 along the longitudinal direction.

In the configuration of this embodiment, the moment M acting on the swash plate 11
The force Bf acting on the radial bearing 9 based on
The force Bf1. does not act toward the center of the cylinder bore 12 in the compression stroke, but instead acts toward the partition wall between the cylinder bore 12 on both sides of the cylinder bore 12 in the compression stroke, as shown in FIG. It acts as Br3. Therefore, the elastic deformation of the cylinder bore 12 is more suppressed than in the embodiment described above, in which the force Bf acting on the radial bear 1 tongue 9 acts toward the center of the cylinder bore 12 in the compression stroke. In this embodiment, the width of the recess 26 is preferably 1/4 or more of the diameter of the shaft hole 1a, and the depth of the recess 26 is preferably 1/2 or more of the length of the bearing 9.

Note that the present invention is not limited to the above-described embodiments, and for example, the suction chambers 15 and 16 are placed outside the discharge chambers 20 and 21.
It is also possible to adopt a compressor number having a structure in which the compressor is arranged inside, or to apply it to a variable capacity swash plate type compressor.

[Effects of the Invention] As detailed above, according to the present invention, deformation of the cylinder bore due to the force acting on the cylinder block via the radial bearing based on the moment acting on the swash plate during compression operation is suppressed. The piston slides smoothly inside the cylinder bore, improving the seizure resistance of the piston and cylinder bore. Furthermore, when the piston and cylinder block are made of aluminum alloy to reduce weight and the peripheral surface of the piston is coated with fluororesin, peeling of the coating layer is prevented and sealing performance is ensured over a long period of time.

[Brief explanation of drawings]

1 to 6 show a first embodiment embodying the present invention, in which FIG. 1 is a longitudinal sectional view of the compressor, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. Figure 3 is a schematic perspective view showing a state in which a point load is applied to the cylinder, and Figure 4 is a sectional view showing a deformed state.
Figure 5 is a diagram showing the relationship between the load acting position and the amount of deformation, Figure 6 is a schematic diagram showing the deformation state of the cylinder bore, and Figures 7 and 8
The drawings show the second embodiment, in which Fig. 7 is a schematic diagram corresponding to Fig. 2, Fig. 8 is a sectional view of main parts, Fig. 9 is a sectional view of the conventional device, and Fig. 1O is a schematic diagram corresponding to Fig. 2. A schematic diagram showing the state of the front side cylinder bore in the state shown in Fig. 9, and Fig. 11 is a schematic diagram showing the state of the front cylinder bore in the state shown in Fig. 9.
FIG. 3 is a schematic diagram showing the state of the rear cylinder bore in the state shown in the figure. Cylinder blocks 1, 2, shaft holes 1a, 2a, valve plates 3, 4, front housing 5, rear housing 6
, swash plate chamber 8, radial bearing 9, drive shaft 10, swash plate 11. Cylinder bore 12, piston 13, recess 26, force Bf, Br, moment M1 compression chamber Pf, Pr.

Claims (1)

[Claims] 1. A swash plate chamber and cylinder bores located opposite the front and rear sides of the swash plate chamber are formed in the cylinder block to which front and rear housings are joined at both front and rear ends, and compression is applied to the front and rear sides within the cylinder bore. In a swash plate compressor that reciprocally accommodates a piston for reciprocating and drives the piston reciprocally via a swash plate installed on a drive shaft rotatably supported by a cylinder block, a bearing that supports the drive shaft A swash plate compressor in which a recess that opens toward the valve plate is formed at least in a portion of the peripheral surface of the shaft hole formed in the cylinder block that corresponds to a straight line connecting the center of the cylinder bore and the center of the drive shaft. .