JP3744861B2 - Compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a compressor for a fluid that can be used for the purpose of compressing a refrigerant in an air conditioner mounted on a vehicle, for example.
[0002]
[Prior art]
Examples of conventional compressors are disclosed in Japanese Patent Laid-Open Nos. 7-19164 and 2001-234857. One such structure is illustrated in FIG. These compressors usually belong to a type called “swash plate type variable capacity compressor” or “piston type variable capacity compressor”, and the outer shells thereof are a front housing 1 and a cylinder block. 2 and the rear housing 3 are integrated by means such as a through bolt (not shown). Pistons 7 are respectively inserted into the plurality of cylinder bores 21 formed in the intermediate cylinder block 2, and reciprocating motion is forced by the common swash plate 5 through the shoes 8. The swash plate 5 is rotationally driven by a long drive shaft 4 that extends through the center of the swash plate 5 to the center of the cylinder block 2. The tip of the drive shaft 4 is supported by a bearing 64 provided in the cylinder block 2.
[0003]
In the operating state, the piston 7 reciprocates in the cylinder bore 21 by the swinging motion of the swash plate 5 that rotates together with the drive shaft 4, so that the working chamber 21 a expands and contracts, thereby forming the central portion of the rear housing 3. A large volume of discharge formed in the outer peripheral portion of the rear housing 3 through the discharge valve 11 after a fluid such as a refrigerant from the suction chamber 31 is sucked into the working chamber 21a through the suction valve 13 and compressed. It is discharged into the chamber 32. Since this compressor can change the inclination angle of the swash plate 5 steplessly, the discharge capacity can be continuously changed.
[0004]
In this type of compressor that reciprocates the piston and compresses the fluid, the suction of the fluid from the suction chamber 31 to the working chamber 21a and the discharge of the fluid compressed in the working chamber 21a to the discharge chamber 32 are performed. Since both are performed intermittently, fluid pressure fluctuations (pulsations) occur in the suction chamber 31 and the discharge chamber 32. As a result, noise such as vibration and sag may be generated, so that pressure fluctuations in the suction chamber 31 and the discharge chamber 32 are suppressed, and the flow of fluid flowing into and out of the compressor is smoothed. Therefore, conventionally, the volume of the suction chamber or the discharge chamber is designed to be as large as possible. Therefore, it is an unavoidable problem that, as a countermeasure for preventing vibration and noise, it is inevitable that the size of the entire piston-type compressor is increased by increasing the volumes of the suction chamber and the discharge chamber.
[0005]
[Problems to be solved by the invention]
The present invention responds to this problem, which can be said to be the fate of a piston compressor, by sufficiently increasing the volume of the suction chamber and the discharge chamber as much as possible to sufficiently suppress the fluid pressure fluctuation, and to reduce vibration and noise. Piston type that is much smaller than conventional compressors that have the same level of discharge capacity by introducing new means that prevent the generation of the compressor but does not increase the overall size of the compressor It aims to provide a compressor.
[0006]
[Means for Solving the Problems]
The present invention provides a compressor described in each of the claims as means for solving this problem.
[0007]
In the compressor according to claim 1, a swash plate connected to a drive shaft is provided, and a dead space of a cylinder block including a cylinder bore that receives a piston that reciprocates through the swash plate is used. A communication port for communicating at least one of the muffler chamber as at least one space formed with the suction chamber and the discharge chamber, and an inclination of the swash plate to change the discharge capacity As means for changing the angle, in order to connect the drive shaft and the swash plate, a slide comprising a plurality of pins and a plurality of guide grooves with which the pins engage with each other at a position away from the axis of the drive shaft. A link mechanism is provided. For this reason, since the suction chamber or the discharge chamber communicated with the muffler chamber is substantially in the same state as the volume of the suction chamber or the discharge chamber is increased, suction or discharge pulsation is suppressed by the large volume of the suction chamber or the discharge chamber. However, since the muffler chamber is formed by utilizing the dead space of the cylinder block, the size of the compressor does not increase by providing the muffler chamber. Furthermore, since the swash plate is connected to the drive shaft so that the inclination angle can be changed, the swash plate can operate as a swash plate type variable displacement compressor, and the discharge capacity can be changed steplessly.
[0008]
In the compressor according to claim 2, the shoe pressing plate that has the same inclination angle as that of the swash plate but is prevented from rotating is supported by the swash plate via the drive thrust bearing, and is mounted on the periphery of the shoe pressing plate. The plurality of shoes engaged with the end of the piston can be guided so that the plurality of shoe guide grooves formed in the radial direction can freely slide in the radial direction. Accordingly, the shoe does not directly frictionally engage with the swash plate, so that an efficient swash plate type variable capacity compressor can be obtained. In the case of claim 3, the shoe has a shoe main body provided with a spherical recess fitted to a spherical end portion provided on the piston, and is integrally projected from both sides of the shoe main body to engage with the shoe presser plate. The shoe is smoothly guided by the shoe pressing plate. In either case, the same effect as in the case of claim 1 can be obtained.
[0009]
In the swash plate type variable capacity compressor of claim 4, the drive shaft is supported only by the front end portion of the housing via the bearing. In either case, since the drive shaft does not extend through the swash plate to the cylinder block, a large dead space is generated in the cylinder block. Therefore, a muffler chamber having a large volume can be formed using this dead space, and therefore suction or discharge pulsation can be effectively reduced.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Among the accompanying drawings, FIGS. 1 to 3 show an embodiment in which the present invention is implemented in a swash plate type piston variable displacement compressor. In FIG. 1 which shows the longitudinal cross-sectional structure of the whole compressor in the driving | running state which provides the largest discharge capacity, 1 is a front housing which is a part of outer shell of a compressor, 2 is inserted in the inside of the front housing 1, A cylinder block integrated with the rear housing 3 by a plurality of through bolts 40 is shown. In the cylinder block 2, five or six cylinder bores 21 in the lateral direction (axial direction) in FIG. 1 are formed substantially evenly around the center line. A suction chamber 31 as a space is formed in the outer peripheral portion inside the rear housing 3, and a discharge chamber 32 as a space is formed in the central portion.
[0011]
Reference numeral 4 denotes a drive shaft for receiving rotational power from an external power source, and a disk portion 41 is integrally formed so as to be orthogonal thereto. One arm 42 is provided so as to protrude substantially in the axial direction from a part of the outer periphery of the disc portion 41. In the arm 42, two guide grooves as cams, that is, an upper guide groove 43 and a lower guide groove 44 are formed in a predetermined shape at predetermined positions above and below. The drive shaft 4 is supported by the front housing 1 via radial bearings 402 and 404, and is also supported by the front housing 1 in the axial direction via a thrust bearing 403 that supports the back surface of the disc portion 41. . Note that a shaft seal device 401 is provided at these bearing portions to prevent fluid from leaking from the periphery of the drive shaft 4 to the outside.
[0012]
Reference numeral 5 denotes a swash plate, a generally disc-shaped disk portion 5a, a shaft portion 5b formed so as to protrude from the center portion thereof, and a rim protruding in an annular shape from the disk portion 5a around the shaft portion 5b. It consists of part 5c and the like. The swash plate 5 includes two arms 51 that protrude from the back surface toward the disc portion 41, and supports two pins 52 and 53 between the two arms 51. These pins 52 and 53 are inserted into the upper guide groove 43 and the lower guide groove 44 formed in the arm 42 on the drive shaft 4 side, and are slidably engaged. Thereby, the swash plate 5 can rotate with the drive shaft 4 and can be inclined with respect to the drive shaft 4.
[0013]
A shoe pressing plate 6 having an opening at the center is fitted into the shaft portion 5 b of the swash plate 5, and is rotatably coupled to the swash plate 5 by a pressing plate thrust bearing 601 and a lock nut 9. The shoe presser plate 6 is used to sandwich a shoe 8 and a drive thrust bearing 500, which will be described later, with the swash plate 5. The shaft portion 5b of the swash plate 5 is provided with a male screw portion for screwing the lock nut 9.
[0014]
The specific shape of the shoe 8 rotatably engaged with each spherical end 71 so as to constitute a ball joint together with the spherical end 71 at one end of the piston 7 in the illustrated embodiment is a perspective view. It is clear when referring to. The specific shape of the shoe presser plate 6 will be apparent with reference to FIG. 3 in addition to FIG. However, this example shows a case where the number of pistons 7 is six. The shoe presser plate 6 includes a circular recess 61 at the center, and the presser plate thrust bearing 601 can be accommodated in the recess 61. As described above, an opening 63 that fits into the shaft portion 5b of the swash plate 5 is formed at the center of the recess 61. Shoe guide grooves 62 having a constant width are formed in the periphery of the shoe presser plate 6 by the number of pistons 7.
[0015]
The shoe guide groove 62 is slidably engaged with a shoe main body 8a of a shoe 8 having a shape as shown in FIG. The shoe presser plate 6 is rotatably coupled to the swash plate 5, but the shoe main body 8 a attached to the piston 7 is engaged with the shoe guide groove 62 of the shoe presser plate 6. The rotation of the shoe presser plate 6 is prevented, and only the swinging motion is performed with the inclined rotational motion of the swash plate 5. Along with this, a slight change occurs in the distance between the shoe bodies 8a on the shoe presser plate 6 and the positions thereof. Therefore, dimensions such as the width of the shoe guide groove 62 of the shoe pressing plate 6 are set with a slight margin.
[0016]
The shoe body 8a of the shoe 8 is formed with a spherical recess 8b, and a spherical end portion 71 formed at one end of the piston 7 is fitted into the shoe body 8a, and is secured by a method such as caulking. Thus, a ball joint is formed and engaged with the shoe 8 so as to freely rotate and slide. The piston 7 to which the shoe 8 is attached is slidably inserted into the cylinder bore 21 of the cylinder block 2. Each shoe 8 is formed with a pair of shoe ridges 8c so as to protrude from the shoe body 8a. The shoe ridges 8c are pressed by the portions on both sides of the shoe guide groove 62 formed in the shoe holding plate 6. It is supposed to be.
[0017]
The lock nut 9 screwed into the male screw formed on the shaft portion 5 b of the swash plate 5 presses the shoe pressing plate 6 toward the drive thrust bearing 500 and the swash plate 5 via the pressing plate thrust bearing 601. . As a result, the shoe pressing plate 6 can simultaneously press the plurality of shoes 8 onto the drive thrust bearing 500. In this manner, the thrust bearing 500, the plurality of shoes 8, the shoe pressing plate 6, and the pressing plate thrust bearing 601 are assembled on the swash plate 5. The rim portion 5c of the swash plate 5 serves for positioning the bearing 500 with respect to the disk portion 5a. In addition, 501 and 502 shown in FIG. 1 are ring-shaped plates, and constitute a part of the drive thrust bearing 500.
[0018]
10 is a valve port plate made of a thick plate, and at least one suction port 10a and one discharge port 10b are opened so as to pass through the valve port plate at a position corresponding to each cylinder bore 21. Each suction port 10a can communicate with the working chamber 21a in the cylinder bore 21 and the suction chamber 31 formed in the outer peripheral portion in the rear housing 3. Similarly, the discharge port 10b can connect the working chamber 21a and the discharge chamber 32 formed at the center of the rear housing 3.
[0019]
The suction port 10a of the valve port plate 10 is closed from the cylinder bore 21 side by a part of the suction valve 13 made of one thin spring steel plate. Further, the discharge port 10b is closed from the discharge chamber 32 side by a part of the discharge valve 11 made of a single thin spring steel plate. The discharge valve 11 is fixed at the same time when the valve retainer 12 that protects the discharge valve 11 is screwed to the valve port plate 10 by the bolt 14 and the nut 15. Further, the valve port plate 10 and the intake valve 13 are sandwiched and fixed between the front housing 1, the cylinder block 2, and the rear housing 3 when they are integrated together.
[0020]
As described above, five cylinder bores 21 are formed in the cylinder block 2 or six cylinder bores 21 as in the example shown in FIG. 3, but a considerably large dead space is generated at the center thereof. This is because the drive shaft 4 is supported only by the front housing 1, the tip of the drive shaft 4 does not extend to the cylinder block 2, and no bearing is provided to support the tip. In the illustrated embodiment, the dead space is used to form a muffler chamber 22 as a space, and the muffler chamber 22 is discharged through one or more communication ports 23 formed by drilling the valve port plate 10. 32. Although not shown in the drawings, as another embodiment, the muffler chamber 22 communicates with the suction chamber 31, or the muffler chamber 22 is divided into two parts, one being the discharge chamber 32 and the other being the suction chamber 31. You can also communicate with
[0021]
A specific arrangement example of the communication port 23 is shown in FIGS. In any case, five cylinder bores 21 are formed in the cylinder block 2, and five pistons 7 are used. In the first arrangement example shown in FIG. 4, five communication ports 23 are formed in the crotch portion of the valve retainer 12 having a star shape. This is also the crotch portion of the discharge valve 11 of the same shape that is behind the valve presser 12. In the second arrangement example shown in FIG. 5, a single communication port 24 is perforated so as to penetrate the center of the bolt 14.
[0022]
Next, the operation of the piston type variable displacement compressor as the illustrated embodiment of the present invention will be described. When the drive shaft 4 is rotationally driven by an external power source such as an internal combustion engine or a motor mounted on the vehicle, the arm 42 and the upper and lower guide grooves 43 and 44, 2, The swash plate 5 connected through the two pins 52 and 53 and the two arms 51 rotates integrally with the drive shaft 4. The shoe presser plate 6 is supported by the swash plate 5 through a presser plate thrust bearing 601, and the plurality of shoes 8 engaged with the shoe guide groove 62 are respectively connected to the spherical end of the piston 7. Since it is engaged with the portion 71, it does not rotate, and only when the swash plate 5 is tilted with respect to a virtual plane orthogonal to the drive shaft 4 as shown in FIG. Oscillates with a magnitude corresponding to the inclination angle while sandwiching the drive thrust bearing 500 and the plurality of shoes 8 with the swash plate 5. As a result, the plurality of shoes 8 sandwiched between the shoe presser plate 6 and the swash plate 5 via the drive thrust bearing 500 and the plurality of pistons 7 connected thereto are respectively provided in the cylinder bores 21. Move back and forth.
[0023]
In the case of the illustrated embodiment, the swash plate 5 and the shoe presser plate 6 move when the two pins 52 and 53 move while sliding in the upper guide groove 43 and the lower guide groove 44 on the drive shaft 4 side. Since the inclination angle with respect to the drive shaft 4 changes, the strokes of all the pistons 7 change simultaneously by the same amount. As a result, the discharge capacity of the compressor changes steplessly.
[0024]
Among the working chambers 21a formed on the top surfaces of the plurality of pistons 7, those in the suction stroke expand to a low pressure, so that the fluid to be compressed in the suction chamber 31 therein, for example, the refrigerant of the air conditioner However, the suction valve 13 provided in the suction port 10a of the valve port plate 10 is pushed open to flow in. On the contrary, since the working chamber 21a formed on the top surface of the piston 7 in the pressure feed stroke is reduced, the fluid inside the chamber is compressed to a high pressure and provided in the discharge port 10b of the valve port plate 10. The discharge valve 11 is pushed open and discharged into the discharge chamber 32. In this case, the discharge capacity is approximately proportional to the stroke length of the piston 7 determined by the inclination angles of the swash plate 5 and the shoe presser plate 6.
[0025]
As described above, when the inclination angle of the swash plate 5 and the shoe presser plate 6 is changed, the discharge capacity of the compressor changes. Therefore, in order to control the discharge capacity, in the variable capacity compressor of the illustrated embodiment, all The pressure in the front housing chamber 1a, which is the back pressure of the piston 7, is changed using a pressure control valve (not shown) or the like. Usually, an intermediate pressure between the high pressure in the discharge chamber 32 and the low pressure in the suction chamber 31 is introduced from the pressure control valve into the front housing chamber 1a as a control pressure.
[0026]
If the pressure in the front housing chamber 1a, that is, the back pressure of all the pistons 7 is increased, the balance between the back pressure and the pressure in the working chamber 21a formed on the top surface of each piston 7 is lost. The average position of the plurality of pistons 7 moves toward a position close to the valve port plate 10 until a balanced state is obtained. As a result, the strokes of all the pistons 7 are simultaneously reduced, so that the discharge capacity of the compressor is continuously reduced.
[0027]
Although not shown, when the pressure in the front housing chamber 1a becomes maximum and the inclination angles of the swash plate 5 and the shoe pressing plate 6 become substantially zero, all the pistons 7 are substantially dead. At the position of the point, there is almost no reciprocating motion within the cylinder bore 21.
[0028]
On the contrary, when the pressure control valve (not shown) is operated to reduce the pressure in the front housing chamber 1a, the back pressure acting on the piston 7 is reduced, so that the strokes of all the pistons 7 are increased simultaneously. As a result, the discharge capacity of the compressor increases steplessly. In FIG. 1, the pressure in the front housing chamber 1a is minimized, the inclination angle of the swash plate 5 and the shoe presser plate 6 is increased to the maximum, and the stroke of the piston 7 and the discharge capacity of the compressor are maximized. Indicates the state.
[0029]
One feature of the illustrated embodiment is that a plurality of shoes 8 that are directly engaged with the spherical end 71 of the piston 7 are respectively connected to the swash plate 5 by a single shoe retainer plate 6 to drive thrust bearings 500. The swash plate 5 is supported with respect to the arm 42 on the drive shaft 4 side by using a double slide link mechanism comprising two guide grooves 43 and 44 and two pins 52 and 53. Thus, all the parts related to the swash plate 5 are supported only by the front housing 1 via the radial bearings 402 and 404 and the thrust bearing 403.
[0030]
Accordingly, unlike the conventional swash plate type variable capacity compressor shown in FIG. 6, it is not necessary to extend the tip of the drive shaft 4 until it reaches the cylinder block 2 and to support it by the bearing 64. , A muffler chamber 22 is formed as a space as large as possible using a dead space formed in the center of the cylinder block 2, and the muffler chamber 22 is formed by five communication ports 23 formed in the valve port plate 10. A second feature is that the discharge chamber 32 communicates with the discharge chamber 32.
[0031]
As the discharge chamber 32 and the muffler chamber 22 communicate with each other, the apparent volume of the discharge chamber 32 is remarkably increased. Therefore, the pressure fluctuation (discharge pulsation) of the compressed fluid sent out from the discharge chamber 32 to the outside is effective. It is suppressed. In the illustrated embodiment, the muffler chamber 22 communicates with the discharge chamber 32, but it goes without saying that suction pulsation is suppressed when the muffler chamber 22 communicates with the suction chamber 31 through a communication port (not shown). Further, as described above, when the muffler chamber 22 is divided into two and communicated with both the suction chamber 31 and the discharge chamber 32, both the suction pulsation and the discharge pulsation can be suppressed at the same time.
[0032]
As an additional effect of the present invention, since the drive shaft 4 is supported only by the front housing 1, the drive shaft 4 passes through the central portion of the swash plate 5, and the tip thereof is the central portion of the cylinder block 2. Compared with the case where the bearing is supported by the bearing 64, the configuration is not only simplified, but the length of the drive shaft 4 is remarkably shortened, so that the axial length of the entire compressor can be shortened. In addition, since it is possible to use a presser plate thrust bearing 601 that connects the swash plate 5 and the shoe presser plate 6 with a small diameter, the diameters of the front housing 1 and the cylinder block 2 are also increased in the radial direction. It becomes possible to make it smaller. These are useful for reducing the size and weight of the entire compressor, and simplifying the configuration, greatly contributing to a reduction in manufacturing cost.
[0033]
Although the illustrated embodiment relates to a variable capacity compressor, the present invention is not characterized in that the discharge capacity is variable, and can be applied to a fixed capacity compressor. It is clear that there is. Furthermore, the application target of the present invention is not limited to a swash plate type compressor.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional front view showing a swash plate type variable capacity compressor as a preferred embodiment of the present invention.
FIG. 2 is a perspective view showing an outer shape of a shoe and an engaging portion between pistons.
FIG. 3 is a side view illustrating a related configuration of a shoe presser plate and a shoe.
FIG. 4 is a side view showing a first arrangement example of communication ports to the muffler chamber.
FIG. 5 is a side view showing a second arrangement example of communication ports to the muffler chamber.
FIG. 6 is a longitudinal front view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Front housing 2 ... Cylinder block 3 ... Rear housing 4 ... Drive shaft 5 ... Swash plate 7 ... Piston 8 ... Shoe 10 ... Valve port plate 12 ... Valve presser 22 ... Muffler chamber 23 ... Communication port 24 ... Single communication port 31 ... Suction chamber 32 ... Discharge chamber 64 ... Bearing

Claims (4)

A drive shaft that receives rotational power from a power source;
A swash plate that rotates by being connected to the drive shaft and can be inclined with respect to the drive shaft;
A piston that reciprocates by engaging with the swash plate;
A cylinder block having a cylinder bore for receiving the piston formed parallel to the drive shaft;
A suction chamber for sucking fluid into a working chamber formed in the cylinder bore by the piston;
A discharge chamber in which fluid compressed in the working chamber is discharged;
A muffler chamber as at least one space formed using a dead space of the cylinder block;
A communication port for communicating the muffler chamber with at least one of the suction chamber and the discharge chamber;
As means for changing the inclination angle of the swash plate in order to change the discharge capacity, in order to connect the drive shaft and the swash plate, a plurality of pins at positions away from the axis of the drive shaft, A swash plate type variable capacity compressor comprising a slide link mechanism comprising a plurality of guide grooves with which the pins engage. 2. The swash plate type variable displacement compressor according to claim 1, wherein the swash plate is supported by the swash plate via a drive thrust bearing, which is a rolling bearing, and the same inclination angle as that of the swash plate is obtained, but rotation is prevented. A shoe retainer plate,
A plurality of shoes engaging with a plurality of shoe guide grooves formed in the radial direction on the periphery of the shoe presser plate and sliding in the radial direction, and engaging with an end of the piston A swash plate type variable capacity compressor.   3. The swash plate type variable displacement compressor according to claim 2, wherein the shoe includes a shoe main body having a spherical recess fitted to a spherical end provided on the piston, and the shoe main body integrally. A swash plate type variable displacement compressor characterized by comprising a pair of shoe flanges protruding to both sides and engaging with the shoe pressing plate.   The swash plate type variable capacity compressor according to any one of claims 1 to 3, wherein the drive shaft is supported only by a front end portion of the housing via a bearing. Capacity compressor.

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