JPH0229873B2 - SHUJIKUOKATAMOCHISHIJISHITAKAITENSHABANSHIKIATSUSHUKUKI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotating swash plate type compressor, and particularly to an improvement of this type of compressor having a structure in which the main shaft is supported in a cantilevered manner.

[Prior art]

Rotary swash plate compressors with a cantilever-supported main shaft are disclosed in U.S. Patent Nos. 3552886 and 3712759,
This method is known from publications such as No. 1671 and Japanese Unexamined Patent Publication No. 55-29040.

A typical structure of this type of compressor will be explained with reference to FIG.

In FIG. 5, a cylindrical casing 10 has a cylinder block 11 fitted and fixed at one end, and a front housing 12 fixed at the other end.
A crank chamber 13 is formed which also serves as a storage chamber for lubricating oil. A wedge-shaped rotor 14, which is a rotating swash plate disposed within the crank chamber 13, is mounted on a radial needle bearing 1 in the center of the front housing 12.
The main shaft 16 is rotatably inserted through the main shaft 16 through the shaft 5.
and is opposed to the front housing 12 via a thrust needle bearing 17.

Also arranged within the crank chamber 13 is a ring-shaped swing plate 19 that faces the inclined surface of the rotor 14 via a thrust needle bearing 18 . It is swingably received via a rotatable steel ball 21.
The swing center shaft body 20 is fitted into the center hole 22 of the cylinder block 11, and is movable in the axial direction but is prevented from rotating. It is energized towards 19. The biasing force of the spring 23 at this time can be adjusted by turning the screw body 24 screwed into the central hole 22.

The oscillating center shaft 20 also has a bevel gear 20b at its tip, and this bevel gear 20b meshes with a bevel gear 25 fixed to the oscillating plate 19, thereby preventing rotation of the oscillating plate 19. ing.

Furthermore, a plurality of cylinders 26 are formed in the cylinder block 11, and these cylinders 26
A piston 27 is slidably inserted into each of the . These pistons 27 are connected to the vicinity of the periphery of the swing plate 19 by rods 28. The connection between the rod 28 and the rocking plate 19 and the connection between the rod 28 and the piston 27 are both performed by ball and socket joints.

A cylinder head 30 is superimposed on one end of the cylinder block 11 via a gasket (not shown) and a valve plate assembly 29, and is fixed thereto by bolts 31. The cylinder head 30 has a suction chamber 32 near the outer periphery.
It has a discharge chamber 33 in the center. The valve plate assembly 29 includes a valve plate having an inlet port 34 that communicates each of the cylinders 26 with the suction chamber 32 and a discharge port 35 that communicates each of the cylinders 26 with the discharge chamber 33;
A flexible suction valve provided on the cylinder 26 side of the suction port 34 and a flexible discharge valve provided on the discharge chamber 33 side of the discharge port 35 are fixed together with a fixing bolt 36. Note that 37 is a valve holder for preventing excessive deflection of the discharge valve, and this is also integrally fixed to the valve plate assembly 29 with a fixing bolt 36.

In the above-described structure, when the main shaft 16 is rotated by an appropriate rotation drive means, the rotor 14 rotates within the crank chamber 13, and the rocking plate 19 rotates around the steel ball 21 according to the inclined surface of the rotor 14. Because it oscillates without rotating, the plurality of pistons 27 slide back and forth within the cylinder 26 at different times, and as a result, the fluid in the suction chamber 32 is sucked into the cylinder 26 through the suction port 34 and discharged. It is discharged into the discharge chamber 33 through the outlet 35. Actually, the suction port 38 provided in the cylinder head 30
Since the cooling circuit is connected between the cooling circuit and the discharge port (not shown), the refrigerant in the cooling circuit circulates while repeatedly condensing and evaporating.

Note that the biasing force of the spring 23 is the thrust bearing 1
7, rotor 14, thrust bearing 18, rocking plate 19, bevel gear 25, steel ball 21, rocking center shaft body 2
It is adjusted by the screw body 24 to ensure an appropriate axial clearance between each part, and acts to absorb axial movement of each part due to dimensional changes due to temperature changes or machining dimensional errors of each part. .

[Problems to be solved by the invention]

The rotating swash plate compressor configured as described above is, for example,
It is used as a refrigerant compressor for car coolers, and has achieved a sufficient lifespan under normal use. However, when used under harsh conditions such as long-term operation in extremely hot weather, the rolling or sliding parts may seize and a sufficiently long life cannot be guaranteed.

When investigating the cause of this seizure, it was discovered that the contact surface of the radial needle bearing of the main shaft 16 had peeled off, and the pieces caused damage to the rolling and sliding parts, eventually causing the clutch to slide. It was found that this resulted in seizure of parts and rolling parts.

FIG. 6 is a developed view of the bearing contact surface of the main shaft 16, in which peeling has occurred in area A and area B.
had a shiny surface indicating that it had come into contact with the bearing. In other words, it was found that the main shaft 16 did not come into uniform contact with the bearing, resulting in uneven contact.

It is thought that such a bias is due to the following causes.

The external force acting on the rotor 14 is caused by the piston 27
The total gas pressure F ₁ based on the compression by and the spring 23
The biasing force _F2 is due to The total gas pressure F ₁ acts at a point A near the connection point with the piston rod 28 of the piston at top dead center, as shown in FIG. That is, it is near the outer circumferential portion of the rotor 14 where the thickness in the axial direction is greater. This point A side of the rotor will be referred to as the top dead center side of the rotor. The biasing force F ₂ is the rotor 14
join the center of

However, since the total gas pressure F ₁ and the biasing force F ₂ both act on the inclined surface of the rotor, component forces F ₃ and F ₄ are generated in the direction toward the top dead center of the rotor, that is, in the radial direction, respectively. .

A reaction force F ₅ is generated from the thrust bearing 17 against the axial pressing force (F ₁ +F ₂ ), and the axial force is balanced, but it is balanced by the radial resultant force (F ₃ +F ₄ ). Since there is no force, the rotor 14 is pushed toward the top dead center and receives a counterclockwise moment around the contact point B with the thrust bearing 17 in FIG. As a result, the rotor 14 floats up from the thrust bearing 17 at the bottom dead center side opposite to the top dead center side with respect to the center. Due to this movement of the rotor toward the top dead center side, the lifting of the bottom dead center side, and the relatively small rigidity of the rotor and the main shaft, especially at the connection point, the main shaft 16 is inclined as shown in the figure, and the main shaft 16 is tilted to the C point of the radial bearing. There will be a biased hit at point D. The inclination of the main shaft at this time is θ, which is determined by the axial length of the radial bearing and the radial clearance. In this state,
Reaction forces F ₆ and F ₇ act on the main shaft from the radial bearing 15, and are balanced by F ₃ +F ₄ =F ₆ -F ₇ , and each dimension l ₁ ~
If l ₄ , r ₁ , and r ₂ are determined as shown in Figure 7, the moment will also be maintained in the following equilibrium state.

F ₃ l ₁ +F ₄ l ₂ +F ₆ l ₃ −F ₁ (r ₂ −r ₁ )−F ₂ r ₂ −F ₇ l ₄ = 0 In this way, the main shaft 16 has an inclination θ and is in eccentric contact with the radial bearing. It will rotate while doing so. It is thought that this causes the above-mentioned peeling. Due to this inclination θ, the reaction forces F ₆ and F ₇ exerted from the radial bearing on the main shaft vary depending on the total gas pressure F ₁ and become large during high-load operation, resulting in separation under the severe conditions mentioned above. becomes more likely to occur. Of course, this θ depends on the clearance between the radial bearing and the main shaft, but the normal clearance is about 0° to 0.04°.

Based on this knowledge, the present invention has been developed to ensure that even when operating a compressor under severe conditions, the main shaft and the radial bearing that supports it can be in uniform surface contact with the bearing without uneven contact between the main shaft and the radial bearing that supports it. It is an object of the present invention to provide a compressor that is supported by the compressor and thereby can realize a sufficient life even when used under severe conditions.

[Means for solving problems]

According to the present invention, a main shaft is rotatably supported in the front housing via a radial needle bearing, a wedge-shaped rotating swash plate is attached to the end of the crank chamber of the main shaft, and relative rotation is provided on the inclined surface of the rotating swash plate. In a rotary swash plate compressor in which a main shaft is cantilever-supported so that a piston can reciprocate through a oscillating plate that can be pressed, a contact surface of the radial needle bearing with the main shaft faces inward. As a result, a rotary swash plate compressor is obtained in which the main shaft is cantilevered and is formed as an annular conical surface slightly inclined away from the main shaft.

[Effect]

According to the present invention, when the compressor operates and gas pressure is applied to the rotating swash plate, the resulting rotational moment pushes the rotating swash plate toward the top dead center for the same reason as described above. As a result, the central axis of the main shaft becomes parallel to the top dead center side generatrix of the annular conical surface of the radial needle bearing, and due to the component force of the gas pressure on the inclined surface of the rotating swash plate, Since it is pushed toward the dead center side, the outer surface of the main shaft uniformly contacts the radial needle bearing. As a result, even under severe conditions, there is no uneven contact between the main shaft and the radial needle bearing, and the conventional peeling phenomenon is prevented.

〔Example〕

The present invention will be explained below with reference to Examples.

First, referring to FIG. 1, as described above, the wedge-shaped rotor 14 is fixed to the main shaft 16 that is rotatably inserted through the center of the front housing 12 via the radial needle bearing 15, and It faces the front housing 12 via a thrust needle bearing 17.

The inner circumferential surface of the radial needle bearing 15, that is, the contact surface with the main shaft 16, has an annular conical surface (inwardly, toward the rotor 14) that is slightly inclined away from the main shaft 16. It is formed at an inclination angle θ ₁ ). In the stopped state, the main shaft 16 abuts against the left end of the radial needle bearing 15 so that its axes are parallel to each other. At this time, as shown in the figure, there is a clearance between the main shaft 16 and the inner circumferential surface (contact surface) of the radial needle bearing 15.

Referring to FIGS. 2a and 2b, the radial needle bearing 15 includes a race 15a and a plurality of needles 15.
It is equipped with b. Race 1 as shown in Figure 2a
5a has a thick wall at one end and a thin wall at the other end, and has a tapered outer peripheral surface, that is, an annular conical surface. A plurality of needles 15b are arranged on the inner peripheral surface of the race 15a at predetermined angular intervals. As shown in FIG. 2b, the radial needle bearing 15 is press-fitted into a through hole formed in the center of the front housing 12 from the crank chamber side until it comes into contact with a stopper 15', and is assembled into the front housing. In this assembled state, the inner circumferential surface (contact surface) of the radial needle bearing 15 becomes an annular conical surface, and the end portion with the larger inner diameter of the radial needle bearing 15 faces the crank chamber.

In addition, as shown in Figure 3 a and b, race 1
The inner circumferential surface of 5a is formed into a cylindrical shape, and a plurality of needles 15b are arranged on the inner circumferential surface at predetermined angular intervals to constitute the radial needle bearing 15. on the other hand,
The central through hole of the front housing 12 is tapered so that its diameter gradually decreases from the position facing the crank chamber to the position where the stopper 15' is provided. Then, the radial needle bearing 15 described above is press-fitted into the through hole from the crank chamber side.
Since the inner peripheral surface of the through hole is formed in a tapered shape,
The inner diameter of the radial needle bearing 15 gradually becomes smaller from the crank chamber side. That is, the inner peripheral surface (contact surface) of the radial needle bearing 15 becomes an annular conical surface.

With this configuration, when the compressor operates and gas pressure is applied to the rotor 14, a force that moves the rotor 14 toward the top dead center and a rotational moment generated by the force are generated. As a result, the spindle 1
The outer surface of 6 is uniformly pressed against the radial needle bearing 15 without uneven contact. Therefore, there is no fear of peeling even under severe conditions such as long-term operation under high pressure loads.

This operating state will be explained with reference to FIG.

Similar to the conventional example, when the compressor is in operation, the rotor 1
The external forces applied to 4 are the total gas pressure F ₁ and the axial biasing force F ₂ . Due to these F ₁ and F ₂ , component forces F ₃ and F ₄ act in the direction toward the top dead center, similar to FIG. 7. As a result, the rotor 14 moves toward the top dead center (F ₃
It is pushed by the force of +F ₄ ). As a result, spindle 1
6 contacts the outer end of the radial bearing 15. Then, it rotates around this outer end contact portion M (FIGS. 1 and 4). That is, on the top dead center side, the rotor 1
4 and the main shaft 16 is displaced relative to the rotor so that the angle formed between the thrust race surface side of No. 4 and the main shaft 16 becomes larger.
Let this displacement be Φ.

On the other hand, due to the rotational moment applied to the rotor 14 by F ₃ and F ₄ , the bottom dead center side of the rotor 14 is lifted, but this lifting of the bottom dead center is limited by the axial clearance and axial biasing force described above. Therefore, if the maximum floating angle of the rotor is θ ₂ as shown in FIG. 4, the main shaft 16 is displaced from its inclination angle θ ₁ by θ ₁ −θ ₂ =Φ in the state shown in FIG. 4. It turns out. As a result, the rotor 14 and the main shaft 16
Assuming that the stiffness coefficient of the joint with the main axis 16 is k, in _Fig .
This ensures that the main shaft 16 hits the radial bearing 15 uniformly.

The balance of force and moment in this state is as follows.

This balanced state is expressed by the equations of force balance and moment balance as follows.

F ₃ +F ₄ ′=F ₆ F ₁ +F ₂ ′=F ₅ F ₅・R−F ₄ ′・l ₁ −F ₁ R′−F ₆ (l ₂ +l ₄ )=0 M _s ′=kΦ=F ₆ (l ₂ + l ₄ ) Here, l ₁ , l ₂ , l ₃ , R, R' are the dimensions shown in Fig. 4, F ₂ is the axial biasing force to give θ ₂ , and F ₄
is the radial component of F ₂ , F ₁ and F ₃ are the forces as described above, F ₅ is the drag force from the thrust bearing 17, and F ₆
is the drag force from the radial bearing 15, and M _s ' is the clockwise moment applied to the main shaft due to displacement of the main shaft by Φ (=θ ₁ -θ ₂ ) with respect to the rotor 14.

In this way, during operation of the compressor, the main shaft 16 comes into uniform contact with the radial bearing 15 without uneven contact. This prevents peeling.

Note that among the thrust race surfaces of the rotor 14,
It is preferable to attach an inclination angle corresponding to the above-mentioned θ ₂ to the top dead center side. As a result, the thrust race surface uniformly contacts the thrust bearing 17 due to the lifting of the bottom dead center side, and separation of the thrust race surface is also prevented.

〔Effect of the invention〕

As explained above, according to the present invention, the main shaft is rotatably supported in the front housing via a radial needle bearing, a wedge-shaped rotating swash plate is attached to the end of the crank chamber of the main shaft, and the rotating swash plate is inclined. In a rotary swash plate compressor in which a main shaft is cantilever-supported to cause a piston to reciprocate through a rocking plate pressed so as to be relatively rotatable on a surface, the contact surface of the radial needle bearing with the main shaft is Since it is formed as an annular conical surface that is slightly inclined to move away from the main shaft as it goes inward, gas pressure applied to the rotating swash plate during compressor operation causes the main shaft to reduce rotational moment and top dead center side. As the main shaft receives a radial force directed toward the rotating swash plate, the main shaft is displaced relative to the rotating swash plate, and due to this displacement, a moment based on the joint rigidity between the main shaft and the rotating swash plate acts, and the main shaft moves into the annular cone of the radial needle bearing. Abuts uniformly on the top dead center side generatrix of the surface without uneven contact. Therefore, the present invention has the advantage that the main shaft does not peel off even when used under severe conditions, and the service life can be extended.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention, FIGS. 2a and 2b are views showing an example of a radial needle bearing and the state in which this radial needle bearing is assembled into a front housing, and FIGS. 3a and b is a diagram showing another example of a radial needle bearing and a state in which this radial needle bearing is assembled into a front housing, and FIG. 4 is a cross-sectional view of the main parts similar to FIG. 1, showing the state of the compressor under operating conditions. , 5th
The figure is a sectional view of a conventional example of a rotary swash plate compressor in which the main shaft is supported on a cantilever; FIG. 6 is a developed view of the outer surface of the main shaft supported by the bearing after long-term use in the conventional example;
The figure is an explanatory diagram showing the force applied to the rotor and the resulting state of the rotor and main shaft in a conventional example. 12... Front housing, 13... Crank chamber, 14... Rotor (swash plate), 15... Radial needle bearing, 16... Main shaft, 17... Thrust needle bearing, 19... Rocking plate, 27... …
piston.

Claims (1)

[Claims] 1. A main shaft is rotatably supported in the front housing via a radial needle bearing, a wedge-shaped rotary swash plate is attached to the end of the crank chamber of the main shaft, and the wedge-shaped rotary swash plate is pressed so as to be relatively rotatable on the inclined surface of the rotary swash plate. In a rotary swash plate type compressor in which a main shaft is cantilever-supported to cause a piston to reciprocate through a rocking plate, as the contact surface of the radial needle bearing with the main shaft faces inward, the main shaft is moved away from the main shaft. A rotary swash plate compressor having a cantilever-supported main shaft, characterized in that it is formed as an annular conical surface that is slightly inclined away from the other.