JPH0229870B2 - 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. 4, 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 in 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 rocking plate 19 that faces the inclined surface 14a of the rotor 14 via a thrust needle bearing 18.
The swing plate 19 is swingably received at the tip of the swing center shaft 20 via a rotatable steel ball 21 . The swing center shaft body 20 is the cylinder block 11
It is fitted into the central hole 22 of the hole 20a, and is movable in the axial direction but not rotated, and is biased toward the rocking plate 19 by a spring 23 fitted in the hole 20a. At this time, the biasing force of the spring 23 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 the oscillating plate 19 from rotating. 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 1
9. The screw body 12 is used to ensure an appropriate axial clearance between the bevel gear 25, the steel ball 21, and the swing center shaft 20, and also to prevent dimensional changes due to temperature changes and It acts to absorb the axial movement of each part due to machining dimensional errors.

[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 we investigated the cause of this seizure, we found 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. 5 is a developed view of the bearing contact surface of the main shaft 16, in which peeling had occurred in area A, and area B had become a shiny surface indicating contact with the bearing.
In other words, it has been found that the main shaft 16 does 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
Total gas pressure F ₁ based on compression by and spring 2
3 is the biasing force _F2 . The total gas pressure F ₁ is the 6th
As shown in the figure, the piston acts at a point A near the connection point with the piston rod 28 at the top dead center. 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 urging 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. .

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 not balanced by the radial resultant force (F ₃ +F ₄ ). Since there is no matching force, the rotor 14 receives a counterclockwise moment in FIG. 6 around the contact point B with the thrust bearing 17 on the top dead center side. As a result, the rotor 14 floats up from the thrust bearing 17 at the bottom dead center side opposite to the center with respect to the top dead center side. This rotor 1
4 moves toward the top dead center side and floats toward the bottom dead center side, and because of the relatively small rigidity of the rotor 14 and the main shaft 16, especially at the connection point, the main shaft 16 tilts as shown in the figure and reaches the C point of the radial bearing. This results in a biased hit at point D. At this time, the inclination of the main shaft 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 F ₃
If +F ₄ =F ₆ -F ₇ is balanced, and each dimension l ₁ to l ₄ , r ₁ , r ₂ is determined as shown in FIG. 6, the moment will also be maintained in the following balanced 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. The reaction forces F ₆ and F ₇ that act on the main shaft from the radial bearing due to this inclination θ vary depending on the total gas pressure F ₁ and increase during high-load operation, resulting in peeling under the severe conditions mentioned above. It becomes easier. 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 prevent uneven contact between the main shaft and the radial bearing that supports it even when the compressor is operated under severe conditions. It is also an object of the present invention to provide a compressor that can realize a sufficient service life.

[Means for solving problems]

The present invention rotatably supports a main shaft via a radial needle bearing in a front housing, a wedge-shaped rotating swash plate is attached to the end of the main shaft inside the crank chamber, and the rotating swash plate is connected to a thrust needle bearing on the inner surface of the front housing. A rotary swash plate type compressor in which a main shaft is cantilever-supported and the piston is reciprocated through a rocking plate which is thrust-supported through the rotary swash plate and is pressed so as to be relatively rotatable on the inclined surface of the rotary swash plate. The main shaft is attached to the rotating swash plate at a small angle θ ₁ (the axial length of the radial bearing is l,
The clearance with the main shaft is c, and θ=tan ^-1 (c/
l), the spindle is installed at an angle of θ ₁ θ), so that the main shaft is installed in the radial needle bearing so as to be supported in a state of inclination by the angle of θ. That is.

[Effect]

According to the present invention, when the compressor operates and gas pressure is applied to the rotating swash plate, the resulting rotational moment moves the rotating swash plate toward the top dead center for the same reason as described above, and also toward the top dead center. The opposite side rises with the center at the center. As a result, the central axis of the main shaft becomes parallel to the central axis of the radial needle bearing, and at the same time, due to the displacement of the main shaft with respect to the rotating swash plate, a displacement angle corresponding to the acting moment is generated based on the joint rigidity between the main shaft and the rotating swash plate, and the main shaft The outer surface of the radial needle bearing uniformly contacts the top dead center side surface of 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〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an assembly of a rotor 14 and a main shaft 16 used in carrying out the present invention, and is a sectional view showing a state before being assembled into a front housing.

Referring to the figure, the main shaft 16 is attached at an angle with respect to the rotor 14. In other words, the thrust-supported surface of the rotor 14 (this is called the thrust support surface) is ST, and the axis perpendicular to this thrust support surface ST is OR (hereinafter referred to as the central axis of the rotor).
The main shaft 16 is conventionally mounted so that its center axis O _S is parallel to the OR, but in this embodiment, as shown in the figure, the main shaft 16 is mounted from the OR to the top dead center side of the rotor (i.e., the rotor (with greater thickness) by θ ₁ .

This θ ₁ is the radial bearing (Fig. 2 and Fig. 4 1).
5) is selected such that θ ₁ ≧tan ⁻¹ (c/l), where l is the axial length and c is the clearance with the main axis. θ ₁ is
It is approximately 0.5°.

FIG. 2 is a sectional view showing the rotor and main shaft assembly shown in FIG. 1 (where θ=θ ₁ ) is assembled into a compressor. Housing 12, radial bearing 1
5. Only the thrust bearing 17 is shown, and other parts and related structures are the same as those in FIG. 4, so their illustration is omitted.

Referring to FIG. 2, the main shaft 16 is inserted into the radial bearing 15 of the front housing 12, and the biasing force of the spring 23 is adjusted by adjusting the adjustment screw 24 shown in FIG.
4 thrust race surface 141 is the thrust bearing 17
I will try to meet them face-to-face. At this time, the central axis O _S of the main shaft 16 is inclined from the central axis O _B of the radial needle bearing 15 by an angle θ (=θ ₁ ).

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 4 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. 6. As a result, the rotor 14 moves toward the top dead center (F ₃ +
F ₄ ) is pushed by force. As a result, the main shaft 16 is connected to the outer end contact portion M of the radial bearing 15 (Figs. 2 and 3).
Rotate around the image). That is, the main shaft is displaced relative to the rotor 14 so that the attachment angle θ ₁ of the main shaft to the rotor 14 becomes smaller.

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 side is limited by the axial clearance and axial biasing force described above.
Therefore, we now set the maximum uplift angle of the rotor to the third
Assuming θ ₂ as shown in the figure, the main axis 16 is the third
In the state shown in the figure, the rotor is displaced from the angle θ ₁ by θ ₁ −θ ₂ =φ. As a result, rotor 1
4 and the main shaft 16 is k, then M _S =kΦ, a clockwise moment in FIG. Various wins are guaranteed.

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 ) where l ₁ , l ₂ , l ₃ , R, and R' are the dimensions shown in Fig. 3, and F ₂ is the axial biasing force to give θ ₂ ;
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,
F ₆ is the drag force from the radial bearing 15, and M _S ′ is the installation inclination angle of the main shaft to the rotor 14 from θ ₁ to Φ (= θ ₁ − θ ₂ )
This is the clockwise moment that is applied to the main axis due to the displacement.

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 it is preferable that the thrust race surface 141 of the rotor 14 has an inclination angle corresponding to the above-mentioned θ ₂ on 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.

Furthermore, when the floating angle θ ₂ on the bottom dead center side is larger than θ, the mounting angles θ ₁ and θ ₁ > of the main shaft 16 on the rotor 14
It is preferable to set θ ₂ so that even in the state shown in FIG. 2 in which the main shaft and rotor are assembled into the compressor, a moment due to the rigidity of M=k(θ ₁ −θ) is applied to the main shaft. This ensures that during compressor operation, the rotor's θ ₂
Even if there is such lifting, a moment due to rigidity M=k(θ ₁ −θ ₂ ) acts on the main shaft, and the main shaft contacts the radial needle bearing uniformly without uneven contact.

〔Effect of the invention〕

As described above, according to the present invention, the main shaft is rotatably supported in the front housing via the radial needle bearing, and the wedge-shaped rotating swash plate is attached to the end of the main shaft in the crank chamber. A main shaft is thrust-supported on the inner surface of the front housing via a thrust needle bearing, and a main shaft is cantilevered to reciprocate a piston via a rocking plate pressed so as to be relatively rotatable on the inclined surface of the rotating swash plate. In a rotating swash plate type compressor, the main shaft is attached to the rotating swash plate at a small angle θ ₁ toward the top dead center of the piston with respect to its thrust support surface (provided that the axial length of the radial bearing is l, the main shaft When the _clearance ^between the
The main shaft is supported by the radial needle bearing at an angle of θ (selected as θ), so that the gas pressure applied to the rotating swash plate during compressor operation causes the rotating swash plate to Both the main shaft and the rotary swash plate are subjected to a rotational moment that lifts the bottom dead center side of the rotating swash plate. At the same time, a radial force directed toward the top dead center side acts on the rotating swash plate as a component of gas pressure, so a moment based on the rigidity coefficient of the joint between the main shaft and the swash plate acts on the main shaft. become. As a result, the main shaft is uniformly pressed against the top dead center side surface of the radial needle bearing. Therefore, the rotary swash plate compressor of the present invention has the advantage that the main shaft does not peel off even when used under severe conditions, and its life can be extended.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an assembly of a main shaft and rotor according to the present invention, FIG. 2 is a sectional view of essential parts in an embodiment of the present invention, and FIG. Figure 4 is a cross-sectional view of a conventional example of a rotary swash plate compressor in which the main shaft is cantilever-supported, and Figure 5 is a cross-sectional view of the main parts similar to Figure 2. FIG. 6 is an explanatory diagram showing the force applied to the rotor and the resulting state of the rotor and the 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, 14a...Tapered surface of thrust race, ST...Thrust support surface.

Claims (1)

[Claims] 1. 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 main shaft inside the crank chamber, and the rotating swash plate is thrust onto the inner surface of the front housing via a thrust needle bearing. In a rotary swash plate type compressor, a rotary swash plate type compressor has a cantilever-supported main shaft for reciprocating a piston via a rocking plate which is supported and pressed so as to be relatively rotatable on an inclined surface of the rotary swash plate. The rotating swash plate has a small angle θ ₁ (the axial length of the radial bearing is l, the clearance with the main shaft is c, and θ = tan ^-1 ( c/l), the spindle is installed at an angle of θ ₁ θ), so that the main shaft is installed in the radial needle bearing in such a way that it is supported in an inclined state by the angle of θ. A rotating swash plate compressor with a cantilevered main shaft.