JPH0819913B2 - Rotary compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary compressor, and more particularly to a rotary compressor intended to improve mechanical efficiency by reducing mechanical friction loss.

[Conventional technology]

At least a conventional cylinder, a roller rotating in the cylinder, a crank for rotating the roller, a drive device for driving a rotary shaft integrated with the crank, and a tip end contacting the roller, A rotary compressor having a vane that reciprocates in accordance with the rotation of the rotary shaft and partitions the inside of the cylinder into a suction chamber and a compression chamber, and end plates that shield both end openings of the cylinder has a cylindrical cylinder. .

The fact that the cylinder is cylindrical means that the height of the cylinder is high and not flat.

This increases the amount of gas leaking from the high pressure side to the low pressure side between the cylinder inner surface and the roller outer surface, and between the roller outer surface and the vane, resulting in poor compressor efficiency. However, since the compressor has to be rotated more than necessary, there is a problem that mechanical friction loss increases as a result.

Further, conventionally, regarding the optimum compressor component size for increasing the efficiency of a rotary compressor, see, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Laid-Open No. 119190, the ratio of the height H of the cylinder to the difference (Dc-Dr) between the inner diameter Dc of the cylinder and the outer shape Dr of the roller, that is, H / (Dc-Dr) The one set to 1.65 proximity is known.

This examines the effects of mechanical friction loss, gas leakage, and refrigerant temperature rise in the cylinder on the compressor efficiency of a rotary compressor, and limits the H / (Dc-Dr) ratio,
Under the same operating condition, H / (D
The c-Dr) ratio is experimentally found. But,
When determining the optimum compressor component size at an arbitrary theoretical displacement Vth (that is, cylinder volume), the theoretical displacement Vth is Therefore, if two of the dimensions Dc, Dr, H (or two dimension parameters related to the above dimensions) are not determined, the dimensions of the compressor component are not determined, and H / (Dc-D
r) It cannot be uniquely determined by the ratio alone. Therefore, the actual situation is that the optimum compressor component size for improving the compressor efficiency has not been clarified.

[Problems to be Solved by the Invention]

As described above, the conventional rotary compressor having a cylindrical cylinder has a problem that mechanical friction loss between the cylinder inner surface and the roller outer surface and between the roller outer surface and the vane and the amount of gas leakage are large. Further, in the one disclosed in Japanese Patent Laid-Open No. 119190/1982, the optimum compressor component size for improving the compressor efficiency has not been clarified.

The present invention has been made to solve the above-mentioned problems of the prior art, and its object is to optimize the size of compressor components to minimize mechanical friction loss and reduce the amount of gas leakage, It is intended to provide a rotary compressor capable of improving machine efficiency.

[Means for solving the problem]

In order to achieve the above-mentioned object, the structure of the rotary compressor according to the present invention includes at least a cylinder, a roller rotating in the cylinder, a crank for rotating the roller, and a rotation integrated with the crank. A drive device that drives the shaft, a vane whose tip contacts the roller and reciprocates according to the rotation of the rotating shaft to partition the inside of the cylinder into a suction chamber and a compression chamber, and an end plate that shields both end openings of the cylinder. In the rotary compressor having, the cylinder has a flat shape with a large cylinder diameter and a small cylinder height, and is formed so as to increase the thickness of the roller, and the inner surface of the cylinder and the outer surface of the roller, the outer surface of the roller and the tip of the vane are formed. Assuming that the height of the cylinder is H, the inner radius of the cylinder is Rc, and the outer radius of the roller is Rr, the ratio Rr / The values of Rc and H / Rc are set in the ranges of 0.84 to 0.92 and 0.4 to 0.8, respectively.

[Action]

 The functions of the above technical means are as follows.

The flat shape of the cylinder reduces the height of the cylinder. Gas leaks between the inner surface of the cylinder and the outer surface of the roller,
Because of the contact surface between the roller outer surface and the vane end surface, if the volumes of the compression chambers are the same, the contact surface becomes smaller and the gas leakage decreases due to the cylinder height becoming smaller.
Therefore, compressor efficiency is increased and mechanical friction loss is reduced. However, if the height of the cylinder is made extremely small, the amount of reciprocation of the vane increases and loss is incurred. Therefore, the flatness of the cylinder must be selected to be an appropriate value. In the present invention, the optimum dimensions of the compressor components have been set.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

FIG. 1 is a cross-sectional view of a rotary compressor according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II of FIG.

In the figure, 1 is a cylinder of the rotary compressor 15 (height
H, inner radius Rc, which will be described later in detail) 2 is the cylinder 1
Roller that rotates inside (outer radius Rr, details will be described later), 3
Is a crank that gives rotation to the roller 2. The crank 3 is integrated with the rotating shaft 4 and is directly connected to a motor (not shown) related to a driving device at an upper portion thereof.
Reference numeral 5 denotes a vane that partitions the inside of the cylinder 1 into a suction chamber 7 and a compression chamber 8. The tip of the vane 5 abuts on the roller 2,
It is pushed by the spring 6 and the internal pressure (discharge pressure) of the airtight container 13 outside the cylinder 1 from the rear end, and reciprocates in the vane groove 1a formed in the cylinder 1 as the rotary shaft 4 rotates. As shown in FIG. 2, on the upper and lower end surfaces of the cylinder 1, there are provided an upper end plate 9 and a lower end plate 10 which are end plates which also serve as bearings of the rotary shaft 4 and which shield both end openings of the cylinder 1. , Cylinder 1,
The upper end plate 9, the lower end plate 10, the rollers 2 and the vanes 5 constitute the suction chamber 7 and the compression chamber 8. Reference numeral 14 is a lubricating oil stored in the bottom portion of the closed container 13, and is adapted to be supplied to each sliding portion by the pumping action of the rotary shaft 4.

By the way, when considering the optimization of the component size of this type of rotary compressor, the compressor component size has the greatest influence on the gas leakage amount and the mechanical friction loss. It has also been confirmed that mechanical friction loss accounts for a major portion of the total loss. Further, in recent years, the number of revolutions of a motor has been controlled by an inverter, and the rate of mechanical friction loss has been increasing more and more due to higher speed. Therefore, it is most effective to reduce the mechanical friction loss in order to improve the compressor efficiency.
The optimization of the size of the compressor component is also aimed mainly at reducing the mechanical friction loss, and in the rotary compressor 15, the height H of the cylinder 1, the inner radius Rc of the cylinder 1 and the roller 2 relating to the size of the compressor component. So that the values of the shape parameters ζ (= Rc / Rr) and ξ (= H / Rc), which represent the relationship of the outer radius Rr of dimensionally, are in the ranges of ζ = 0.84 to 0.92 and ξ = 0.4 to 0.8, respectively. Set.

The reason why the values of the shape parameters ζ and ξ are limited in this way will be described with reference to FIGS.

Fig. 3 shows that the theoretical displacement Vth is constant (here, 12.5c
FIG. 3 is a relationship diagram between the shape parameters ζ and ξ and the dimensions of the compressor component when m ³ / rev).

In FIG. 3, the horizontal axis represents the shape parameter ζ (= Rr / Rc), the vertical axis represents the inner diameter Dc (= 2Rc) (mm) of the cylinder 1, and the cylinder 1
Height H (mm) and eccentricity a (= Rc-Rr) (mm),
Shape parameter (= for each compressor component dimension Dc, H, a
H / Rc) values of 0.8, 1.0 and 1.4 are shown by solid lines.

If the values of the shape parameters ζ and ξ are determined, this third
It can be seen from the figure that all compressor component dimensions are determined. As for the characteristic of the change of the compressor component due to the shape parameters ζ and ξ, the eccentricity a decreases as the shape parameters ζ and ξ increase. The inner diameter Dc of the cylinder 1 and the height H of the cylinder 1 increase in size as the shape parameter ξ increases, but the influences of the shape parameter ξ tend to contradict each other. Is larger as ξ is larger.

By the way, the main locations of mechanical friction loss in the cylinder 1 of the rotary compressor 15 are the following three locations shown in FIG. 4 (shown by hatching).

FIG. 4 is a transverse cross-sectional view showing main locations of mechanical friction loss of the rotary compressor.

Side surface of vane (portion A) Tip of vane (portion B) Inner circumference of roller (portion C) Here, the friction on the side surface of the vane is the pressure difference (pc-ps) between the suction chamber 7 and the compression chamber 8 in the cylinder 1. ) and the load Fs applied to the vane side by, since those caused by the reciprocating motion of the vanes 5, in order to reduce the vane side friction loss L _a is necessary to reduce the eccentricity a and the height H of the cylinder 1 I have to. Looking at the shape parameters ζ and ξ,
From FIG. 3, it is necessary to increase both ζ and ξ in order to reduce the eccentricity amount a. However, the smaller the height H of the cylinder 1 is, the smaller the height H of the cylinder 1, and the optimum shape parameter ζ, It can be seen that ξ exists.

Next, the friction at the tip of the vane is generated by the vane pressing force F _N due to the pressure difference between the inside and the outside of the cylinder 1 and the sliding speed between the vane 5 and the roller 2. The magnitude of this vane tip friction loss L _B is Is influenced by the rotation angular velocity ω _P of. on the other hand,
The roller inner circumference friction loss L _C due to the roller inner circumference friction is caused by the load F _P due to the pressure difference in the cylinder 1 being applied to the roller 2 as a load, and the angular velocity ω of the crank 3 and the rotation angular velocity ω of the roller 2 are It is affected by the relative velocity with _P (ω−ω _P ). Therefore, the relationship between the vane tip friction loss L _B and the roller inner peripheral friction loss L _C with respect to the rotation angular velocity ω _P of the roller 2 has the characteristics shown in FIG.

FIG. 5 shows the roller rotation angular velocity and vane tip friction loss,
It is a characteristic view of a roller inner circumference friction loss.

From FIG. 5, the friction losses L _B and L _{C with} respect to the roller rotation angular velocity ω _P have contradictory characteristics, and there exists ω _P such that (L _B + L _C ) is minimized. It suffices to select the dimensions of the compressor constituent parts that achieve such a roller rotation angular velocity ω _P.

The roller rotation angular velocity ω _P can be theoretically obtained from the balance of moments applied to the roller 2, and the relationship with the shape parameters ζ and ξ is as shown in FIG.

FIG. 6 is a relational diagram between the shape parameters ζ and ξ and the roller rotation angular velocity. The horizontal axis represents the shape parameter ξ and the vertical axis represents the rotation angular velocity ω _P (rad / s), and the value of the shape parameter ξ is 0.
6, 0.8, 1.0 and 1.4 are shown by solid lines.

From FIG. 6, ω _P is smaller as ζ is larger and ξ is smaller, which is advantageous for the vane tip friction loss L _B.

FIG. 7 is a diagram showing the relationship between the shape parameters ζ and ξ and the maximum load, where the horizontal axis is the shape parameter ξ and the vertical axis is the maximum load F _P max (kgf).
0.8, 1.0 and 1.4 are shown by solid lines.

From FIG. 7, the smaller the values of ζ and ξ are, the smaller the maximum load load F _P max becomes, and the roller inner peripheral friction loss L _C can be reduced. Also, since this load also acts on the bearings of the upper and lower end plates 9 and 10, it is possible to reduce the friction loss of the bearings.
The smaller ζ and ξ are, the more advantageous.

Above shape parameter zeta, friction loss L _A of xi] and the individual sliding portion, L _B, but is for explaining the relationship between L _C, the friction loss L _A, L _B, L _C and zeta, xi] The respective effects show opposite tendencies, and the total mechanical friction loss of the rotary compressor L _A + L _B + L _C
It is inferred that there are shape parameters ζ and ξ that minimize.

FIG. 8 shows the relationship between the total mechanical friction loss and the shape parameters ζ and ξ.

FIG. 8 is a relationship diagram between the shape parameters ζ and ξ and the total mechanical friction loss. The horizontal axis represents the shape parameter ξ, and the vertical axis represents the total mechanical friction loss (W). For each stage of 1500, 3000, 6000, 10000 rpm, the values of the shape parameter ξ of 0.6, 0.8, 1.0, 1.4 are shown by solid lines.

From FIG. 8, it can be seen that there are shape parameters ζ and ξ that minimize the total mechanical friction loss for various rotation speeds of the rotary compressor from the normal rotation speed to the target high-speed rotation speed. = 1500 rpm, ζ = 0.92, ξ = 0.4,
At n = 10000 rpm, ζ = 0.84 and ξ = 0.8 minimizes the total mechanical friction loss. Therefore, the optimum compressor component size considering these changes in rotational speed is the shape parameter ζ = 0.
It will be obtained by setting in the range of 84 to 0.92 and ξ = 0.4 to 0.8.

By setting the values of the shape parameters ζ and ξ in this way, the diameter Dc of the cylinder 1 is larger than that of the conventional rotary compressor that generally adopts the values of ζ = 0.8 and ξ = 1.2.
Is large and the height H of the cylinder 1 is small, resulting in a flat shape. The radius Rr of the roller 2 is also larger than in the conventional case, and if the diameter of the crank 3 is kept constant, the thickness of the roller 2 increases. Along with this, the main part of the conventional leakage loss,
Leakage amount qm of lubricating oil and refrigerant gas from the roller end surface, which had reduced compressor efficiency, into the cylinder (this leakage amount qm is
If the clearance on the roller end face is the same, it will be in inverse proportion to the roller thickness.) It is effective not only to reduce mechanical friction loss but also to reduce leakage loss, and to improve compressor efficiency. You can

The compression operation of the rotary compressor 15 configured as above will be described.

When the rotating shaft 4 is driven by the motor, the roller 2 freely engaged with the crank 3 rotates in the cylinder 1, and the suction chamber 7 and the compression chamber 8 partitioned by the vane 5 are rotated.
Changes in volume. Crank 3 is in the direction of the arrow (Fig. 1)
When rotated to, the volume of the suction chamber 7 increases and the refrigerant gas is sucked from the suction port 11, while the volume of the compression chamber 8 decreases and the refrigerant gas is compressed and discharged from the discharge port 12 into the closed container 13, A compression action is performed.

In this case, the height H of the cylinder 1 and the inner radius of the cylinder 1
Since Rc and the outer radius Rr of the roller 2 are set as described above, the mechanical friction loss is reduced as compared with the conventional case, and the compressor efficiency is improved.

According to the embodiment described above, in the rotary compressor in which the pressure inside the closed container 13 is maintained at the discharge pressure, the height of the cylinder 1 is H, the inner radius Rc of the cylinder 1 and the outer radius of the roller 2 are Rr. Then, the shape parameter ζ of the compressor component
(= Rr / Rc) and ζ ((= H / Rc) are respectively ζ = 0.84
~0.92, ξ = total mechanical friction loss by setting the range of 0.4 to 0.8 a _{(= L A + L B +} L C) to reduce the leakage amount of the gas while minimizing the compressor efficient rotary compressor There is an effect that it can be provided.

〔The invention's effect〕

As described in detail above, according to the present invention, the size of the compressor components is optimized to minimize the mechanical friction loss, reduce the amount of gas leakage, and improve the compressor efficiency. Can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rotary compressor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line II-II of FIG.
FIG. 8 is for explaining the reason for limiting the shape parameters ζ and ξ, and FIG. 3 shows the relationship between the shape parameters ζ and ξ and the dimensions of the compressor component when the theoretical displacement is constant. FIG. 4 is a cross-sectional view showing the main locations of mechanical friction loss of the rotary compressor, FIG. 5 is a characteristic diagram of roller rotation angular velocity, vane tip friction loss, and roller inner circumference friction loss. FIG. 6 is a relationship diagram between the shape parameters ζ and ξ and each speed of rotation of the roller, and FIG. 7 is a relationship diagram between the shape parameters ζ and ξ and the total mechanical friction loss. DESCRIPTION OF SYMBOLS 1 ... Cylinder, 2 ... Roller, 3 ... Crank, 4 ... Rotating shaft, 5 ... Vane, 7 ... Suction chamber, 8 ... Compression chamber, 9 ... Upper end plate, 10 ... Lower end plate, 15 ... Rotary compressor, H ... Cylinder Height, Rc… inner radius of cylinder, Rr… outer radius of roller.

Claims (1)

[Claims] 1. A cylinder, at least a roller rotating in the cylinder, a crank for rotating the roller, a drive device for driving a rotary shaft integrated with the crank, and a tip of the roller contacting the roller. In a rotary compressor having a vane that reciprocates according to the rotation of the rotating shaft to partition the inside of the cylinder into a suction chamber and a compression chamber, and an end plate that shields both end openings of the cylinder, the cylinder having a cylinder diameter of The height of the cylinder is designed to have a large flat shape with a small cylinder height, and to increase the thickness of the roller to reduce the contact surface between the cylinder inner surface and the roller outer surface and between the roller outer surface and the vane tip. Is H, the inner radius of the cylinder is Rc, and the outer radius of the roller is Rr, the values of the ratios Rr / Rc and H / Rc are 0.84 to 0.92 and 0.4 to 0.8, respectively. Rotary compressor is characterized in that so as to set.