JP2586433B2 - Rotary compressor - Google Patents

Description

The present invention relates to a compressor, and is effective when used as, for example, a refrigerant compressor for an automobile air conditioner.

[Conventional technology and its problems]

Conventionally, a compressor having a wave plate, a piston and a roller has been known as this type of compressor (for example, Japanese Patent Application Laid-Open No. Sho 57-11418).

However, the above-mentioned publication does not limit the number of pistons at all, and does not mention at all the combination of the number of uneven cycles of the wave plate and the number of pistons, the technical reason thereof, and the like.

The present inventors have conducted various studies on this type of compressor. As a result, it has been found that the vibration caused by the inertial force of the piston is large, and when mounted on an automobile, the compressor causes vibration and noise as a source. Was. Regarding this point, the contents of the study conducted by the present inventors will be described below.

In this type of compressor is considered to be due to the inertia force of the movable portion as a vibration source, in this case there is a centrifugal force and inertial force of the piston of the wave plate, and inertia couple M _wg as shown in FIG. 4 A shaft axial force _Fp is generated, causing the compressor to vibrate periodically. In the drawing, reference numeral 400 denotes the center of the inertial couple.

In general, a sinusoidal curve is used for the shape of the wave plate in order to make the velocity, acceleration and jerk of the piston a smooth curve. Now, the shape of the wave plate , The minute portion Δγ · Δ shown in FIG. 5 to FIG.
Weight of θ: ΔW is And the centrifugal force of this minute portion: ΔF is Is represented by

Here, the inertial couple around the absolute coordinate y-axis shown in FIGS. 5 to 7 will be considered. Assuming that the clockwise direction in FIG. 6 is positive, the inertial couple due to the centrifugal force of the minute part: ΔM
_wy And the inertial couple around the y-axis due to the centrifugal force of the entire wave plate: M _wy is Where the integral term is Therefore, M _wy = 0, which indicates that the centrifugal force of the (n2) wave plate having a plurality of uneven cycles is balanced irrespective of the number of uneven cycles, and no inertial couple is generated.

In other words, the inertia balance of this type of compressor is determined only by the reciprocation of the piston.

Therefore, the inertial force of the piston will be described below. Now, consider a two-concave cycle / three piston compressor as shown in FIG.

Piston displacement: Z (θ) as described above Then, the piston acceleration: a (θ) becomes a (θ) = − 2S _p ω ² sin (2θ + α), and the piston inertia force: F _ii is It is represented by

Usually, in this type of compressor, a plurality of pistons are arranged at equal angles in order to suppress torque fluctuation and pressure pulsation.
In this case, the interval is 2π / 3. Therefore, the synthetic inertia couple around the y-axis due to the inertial forces of the three pistons: M _py R: The distance from the Z axis (the center axis of the shaft) to the center of gravity of the piston. This resultant moment causes the compressor to vibrate.

[Problems to be solved by the invention]

The present invention has been devised in view of the above points, and by limiting the number of pistons with respect to the number of uneven cycles of the wave plate, it is possible to inertia balance the completion force of the movable parts of the compressor, and as a result, It is another object of the present invention to reduce vibration caused by compressor operation.

〔Constitution〕

In order to achieve the above object, in the present invention Is a non-integer, Is other than an integer, and The relationship between the number of concave and convex cycles of the wave plate and the number of pistons is determined so that also is not an integer.

〔Example〕

FIG. 1 shows an embodiment of the compressor of the present invention. 300 in the figure
Is a shaft, which is rotatably supported by the housing 301. Reference numeral 302 denotes a front housing, on which a magnet clutch (not shown) is mounted, and the rotational force of an automobile driving engine is transmitted to the shaft 300 via the magnet clutch. An oil seal 303 is interposed between the front housing 302 and the shaft 300, and prevents oil and the like inside the housing from flowing out along the shaft 300 to the outside.

A plurality of cylinder portions 304 are formed in the housing 301 (shown in FIG. 2).
05 is slidably disposed. And piston 305
Receives the displacement of the wave plate 100 via the roller 200 as a cam follower, and reciprocates in the cylinder 304. The space formed by the cylinder portion 304 and the end of the piston 305 serves as a pressure chamber 306, and the pressure chamber 306 changes in volume according to the displacement of the piston 305.

End plates 307 and 308 cover both ends of the housing 301. A front housing 302 is provided outside one end plate 307, and a rear housing 309 is provided outside the other end plate 308. A suction chamber 310 and a discharge chamber 311 are formed in the front housing 302 and the rear housing 309. The two chambers 310, 311 communicate with the pressure chamber 306 via suction holes and discharge holes formed in the end plates 307, 308. doing.

Therefore, based on the increase in the volume of the pressure chamber 306, the refrigerant is sucked into the pressure chamber 306 from the evaporator side (not shown) of the refrigerant cycle via the suction chamber 310 and the suction hole. Next, based on the decrease in the volume of the pressure chamber 306, the refrigerant is compressed in the pressure chamber 306, and the refrigerant whose pressure has been increased to a predetermined value is discharged.
To the condenser side (not shown) of the refrigeration cycle.

In the compressor of the present embodiment, the inertial force of the movable portion during the operation of the compressor is balanced, so that the vibration accompanying the compressor operation can be reduced. In addition, torque fluctuation and pressure pulsation are also reduced at the same time.

The above-mentioned means have been found by the present inventors after examining the relationship between the combination of the number of cycles of the concavo-convex cycle of the wave plate and the number of pistons and the inertia balance.

As described above, the centrifugal force F _c of the wave plate 100 (fourth
The characteristic of this type of compressor is that the balance is performed by the wave plate itself regardless of the number of concave and convex cycles. Therefore, attention is paid to the inertia force of the piston 305. Now, assuming that the number of uneven cycles of the wave plate 100 is n, the piston displacement: Z (θ), the piston acceleration: a (θ), and the piston inertia force: F _ii (θ) can be expressed by the following equations.

Therefore, inertia couple around the y-axis due to the piston 305 inertia force:
M _pyi Becomes

Here, assuming that the m pistons 305 are arranged at an equal distance (R) from the center axis of the shaft 300 and at equal angular [2π / m] intervals, a synthetic inertial couple around the y-axis: M _py Is Is represented by Focusing on the numerator of the fractional term in the above equation, sin
(N + 1) π, sin (n−1) π, and n is 0 because both are natural numbers of 2 or more. That is, the denominator of this fraction term, Is zero and becomes indefinite, indicating that the synthetic inertia couple: M _py is 0, that is, it is perfectly balanced.

In other words, in order to balance the combined inertial couple due to the piston 305 inertial force, To make sure that both do not become 0, It can be seen that the number of pistons (m) should be selected with respect to the number (n) of uneven cycles of the wave plate 100 so that both are not integers.

Next, the shaft axial force will be described. As described above, the piston inertia force: F _ii (θ) is And the synthetic inertial force for m pistons: F _p Is transformed. Again, focusing on the numerator of the fractional term as described above, it is sinnπ, and n is a natural number of 2 or more.
Becomes This is also a fractional term Of these, as long as n / m is not an integer, the resultant force in the shaft axial direction: _Fp becomes 0, and the balance is complete.

That is, the piston inertia force in the axial direction of the shaft combined force F _p a in order to balance n / m is the number of irregularities cycles of the wave plate so as to not an integer to (n), it is selected the number of pistons (m) Good.

In other words, the number of pistons is Is satisfied at the same time, the inertial couple and the axial axial inertial force can be balanced, and the vibration of the compressor can be extremely reduced.

With this combination, the relationship shown in Table 1 is obtained.

By the way, the combination of the number of uneven cycles of the wave plate and the number of pistons is closely related to the compression timing of each piston. That is, depending on the combination, the compression timings of the plurality of pistons are synchronized, and the characteristics of low torque fluctuation and low pressure pulsation due to the plurality of pistons (multi-cylinder), which are advantages of this type of compressor, are diminished.

Therefore, in the compressor of this example, the number of pistons 305 is further limited. That is, in order to constitute a compression chamber around the piston in this type of compressor, one piston compressor timing by a shaft rotation angle interval: theta _n is n: Wave plate unevenness cycle number. Further, the shaft rotation angle interval: θm of the compression timing of adjacent pistons is m: Number of pistons, that is, when θ _n and θ _m are in a multiple relationship, the compression timings of the plurality of pistons are synchronized.

That is, the number of pistons is limited to the number shown in Table 1 with respect to the number of wave plate concavo-convex cycles, and a common divisor is provided between the numerical value of {2 × (number of concavo-convex cycles)} and (number of pistons). By limiting the number to no, the vibration of the compressor can be reduced without diminishing the advantages of the multi-cylinder. This combination is shown in Table 2.

Based on the relationship described above, the wave plate 100 according to the present example has a waveform shape having two concavo-convex cycles as shown in a developed view of FIG. On the other hand, piston 305
Are arranged at equal distances from the center axis of the shaft 300 and at equal angular intervals. For that reason, Respectively Are not integers. In addition, (number of uneven cycles ×
2) There is no common divisor between 4 and (number of pistons) 5. When the combined inertia couple: M _py and the shaft axial direction combined force: F _p are actually calculated for this combination, both become 0,
It is possible to completely balance the inertial force of the movable part that causes the compressor to vibrate.

Even if the wave plate is not a perfect sine wave, it is needless to say that a great effect on vibration reduction can be obtained by limiting the number of pistons of the present invention.

〔The invention's effect〕

The compressor of the present invention having the above-described configuration has an excellent effect that vibration based on the inertial force of the piston is greatly reduced, and generation of abnormal noise and the like is suppressed.

[Brief description of the drawings]

1 is a cross-sectional view showing one embodiment of the compressor of the present invention. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, FIG. 3 is a development view showing a wave plate shown in FIG. FIG. 4 is a sectional view for explaining the inertia force of the movable part of the compressor, FIG. 5 is a view showing a method of calculating the centrifugal force of the wave plate, and FIG. 6 is VI-VI in FIG.
FIG. 7 is a vertical sectional view taken along the arrow, FIG. 7 is a sectional view taken along the line VII-VII of FIG.
FIG. 8 is a front view showing an end surface of a cylinder portion of a compressor having a combination of two uneven cycles, three pistons and two examined by the present inventors. 100… Wave plate, 200… Roller, 300… Shaft, 301… Housing, 304… Cylinder, 305…
piston.

Claims (3)

(57) [Claims] A housing having a cylinder portion therein;
A shaft rotatably supported by the housing;
A wave plate that rotates integrally with the shaft, a piston that reciprocates in the cylinder portion, and a cam follower that is interposed between the piston and the wave plate and that transmits a bending change of the wave plate to the piston. Between the number of uneven cycles of the wave plate and the number of uneven cycles of the wave plate (number of uneven cycles + 1) / (number of pistons) ≠ integer and (number of uneven cycles) / (number of pistons) ≠ integer and (number of uneven cycles-1) / (Number of pistons) ≠ integer A rotary compressor characterized in that the number is limited to the number that satisfies the relationship: 2. The number of pistons according to claim 1, wherein the number of pistons is limited to a number having no common divisor between the number of irregularities of the wave plate and twice the number of cycles. Rotary compressor. 3. The rotary compressor according to claim 1, wherein said cam follower is a roller.