JPS6122152B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary compressor having vanes, and provides a highly efficient rotary compressor as a refrigerant compressor in, for example, an automobile air conditioner.

Conventionally, vane slits are formed in the rotor,
The vane is arranged so as to pass through this vane slit, and as the rotor rotates, the tip of the vane
A compressor that is in sliding contact with the inner surface of the housing has been known (Japanese Patent Application Laid-Open No. 112215/1983).

However, in this conventional compressor, the inner surface shape of the housing is a Limason curve that can be expressed as r=-dcosθ+d+R, considering the rotor center as the center of polar coordinates. Here, d represents an arbitrary constant, and R represents the rotor radius.

That is, the shape change of the inner surface of the housing of this conventional one is as shown in FIG. In this conventional compressor, the low-pressure side and the high-pressure side are separated at θ=0, that is, at the point r=R where the housing and rotor touch, and there is a line seal only at this contact point. In other words, this line seal prevents refrigerant and the like from moving from the high pressure side to the low pressure side.

However, in reality the rotor at the contact point,
The clearance between the housings is set at about 0.02 to 0.03 mm to account for thermal expansion, rotational center deviation, etc. For this reason, refrigerant and the like leak from the high-pressure side to the low-pressure side through this clearance, resulting in a decrease in volumetric efficiency. In Figure 7, the curve r=-dcosθ+d+
The curve marked R indicates this point of contact. As shown in FIG. 7, the inner surface of the housing formed by the conventional Limason curve has extremely few contact points with the rotor.

Here, the acceleration applied to the vane is obtained by determining the shape of the inner surface of the housing because the vane tip is always in contact with the inner surface of the housing.
In the conventional Limason-shaped housing as shown in FIG. 5, the vane is subjected to the acceleration shown in FIG. 6. As is clear from FIG. 6, the conventional vane had good acceleration in terms of vane acceleration. In other words, the vane acceleration was expressed by a simple function, and therefore had a very smooth trajectory. Therefore, the noise generated by the movement of the vanes can be kept small.

The present invention was devised in view of the above points, and by making the inner surface of the housing a special shape,
The purpose of the present invention is to provide a good seal at the contact surface between the inner surface of the housing and the rotor while making the movement acceleration of the vane smooth. That is, in the present invention, the acceleration applied to the vane is basically made into a sinusoidal curve, so that the acceleration applied to the vane does not vary significantly. Furthermore, the present invention allows for a larger contact surface at the portion of the inner surface of the housing that comes into contact with the rotor.

In order to achieve the above object, in the present invention, the inner surface of the housing is shaped so that the moving acceleration of the vane can be expressed by the following equation. That is, the moving acceleration of the vane r=C ₁ (cosθ−
cos3θ) However, the shape is such that _C1 is a constant and θ is the rotation angle.

An embodiment of the present invention will be described below based on the drawings. Reference numeral 1 in FIG. 1 denotes a housing having an inner surface according to the present invention, and a rotor 2 is rotatably disposed within the housing 1. The rotor 2 is provided with a rotor slit 2a passing through its center, and the vane 3 is slidably inserted into the rotor slit 2a. Further, both ends of the vane 3 are brought into sliding contact with the inner circumferential surface of the housing 1. FIG. 2 shows the inner surface shape of the housing 1 according to the present invention. Here, R represents the rotor radius, and 2d represents the maximum protrusion amount of the vane. The inner shape of this housing 1 is the vane 3 relative to the lotus slit 2a.
The relative sliding acceleration ¨r is determined as shown in the following equation.

¨r=C ₁ (cosθ-cos3θ) = _C1 (cosωt-cos3ωt) θ: Rotation angle However, θ=O is point A, C ₁ : Constant, ω: Angular velocity of rotor 2, t: Time Next, use this formula as follows: Vane 3 is integrated with respect to time t.
Find the relative speed r within the rotor slit 2a.

r=C ₁ (1/ωsinωt−1/3ωsin3ωt)+C _2Here , when θ=0, r=0, so C ₂ =0 Integrating this equation again with respect to time t, the trajectory of the tip of the vane 3, i.e. Determine the inner surface shape r of the housing 1.

r=-C ₁ (1/ω ² cosωt-1/9ω ² cos3ωt
)+C _3In this case, when θ=0, r=R, and when θ=π, R+
2d, so C ₁ =9/8dω ² and C ₃ =d+R.

Therefore, the inner shape of the housing is r=-9/8dω ² (1/ω ² cosωt-1/9ω ² c
os3ωt) +d+R=-9/8d(cosθ-1/9cos3θ)+
The sliding acceleration of the vane 3 that contacts and slides along the inner surface shape of the housing 1 is expressed as ¨r=9/8dω ² (cosθ−cos3θ).

These curves are shown in FIGS. 3 and 4.

Here, FIGS. 5 and 6 show the inner surface shape of a conventional housing having an inner surface shape formed by a Limason curve with a vector radius r, and the sliding acceleration of a vane that slides in contact with the inside of the housing. When comparing this FIG. 5 and the above-mentioned FIG. 3, the difference is not noticeable at first glance. However, when the vicinity of θ=0, that is, the vicinity of the contact point A between the inner surface of the housing 1 and the rotor 2 is enlarged as shown in FIG. 7, a large difference in the change in the vector radius r becomes apparent. That is, the compressor according to the present invention and the conventional compressor have the same size (R = 26 mm,
If we compare the range in which the clearance between the housing 1 and the outer diameter of the rotor 2 is 0.01 mm or less when d = δ mm), in a compressor with a conventional shape, the range in which this clearance is 0.01 mm or less is only 6 degrees. On the other hand, in the case of the present invention, the range is as much as 28 degrees, and it can be seen that in the case of the present example, a face seal is substantially formed between the housing 1 and the rotor 2. By configuring this face seal, leakage of refrigerant, etc. from the high pressure side to the low pressure side can be significantly reduced, and the volumetric efficiency can be improved. Also, since the rotor 2 has a rotor slit 2a open on its outer circumferential surface, the housing 1
In the case of the conventional shape in which there is a line seal between the rotor 2 and the rotor 2, when the rotor slit 2a passes through point A, even the line seal disappears, increasing the leakage of refrigerant, etc. On the other hand, in the present invention, since the seal length is guaranteed to be longer than the width of the opening surface of the rotor slit 2a, refrigerant leakage through the opening surface of the rotor slit 2a as in the conventional compressor does not occur.

Moreover, in the present invention, the acceleration ¨r of the vane 3 is C ₁
Housing 1 so that (cosθ−cos3θ)
Since the inner surface shape is determined, in addition to the sealing effect at the contact point A, a low noise effect can also be expected.
That is, the frequency component of the acceleration of the vane 3 as the rotor 2 rotates is a low frequency component determined by cos θ (cos ωt) and cos 3 θ (cos 3 ωt), that is, ω/2π and 3ω/2π, and is generally a problem as noise. Since it does not have high frequency components, it is possible to provide an excellent rotary compressor with low noise.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the compressor of the present invention, Fig. 2 is an explanatory view showing the inner surface shape of the housing of the compressor shown in Fig. 1, and Fig. 3 is an explanatory view showing the radial change of the housing shown in Fig. 2. FIG. 4 is an explanatory diagram showing the acceleration of the vane of the compressor shown in FIG. 1. FIG. 5 is an explanatory diagram showing the radial change of the housing of a conventional compressor. FIG. 7 is an explanatory diagram showing a comparison between the housing shape of the compressor shown in FIG. 1 and the housing shape of a conventional compressor. 1...housing, 2...rotor, 3...vane.

Claims (1)

[Claims] 1. A cylindrical housing, a rotor that is arranged eccentrically within the housing and rotates by receiving a driving force from the outside, and a rotor that is slidable in a rotor slit provided in the diametrical direction of the rotor. a vane disposed at the inner surface of the housing with both tips always in contact with the inner surface of the housing, and the relative acceleration r of the vane with respect to the rotor slit is ¨r=C ₁ (cos θ − cos 3 θ) where C ₁ is a constant; A rotary compressor characterized by being configured such that θ: rotation angle.