JPH0696961B2 - Scroll fluid machinery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scroll fluid machine that functions as a compressor, an expander, and a vacuum pump, and more particularly, to a scroll fluid machine that faces a sliding surface of a counterpart scroll. The present invention relates to a scroll fluid machine in which a seal member is fitted into a wrap end surface via a groove having a rectangular cross section.

“Prior Art” Conventionally, as shown in FIGS. 5A and 5B, a fixed scroll 10 in which a first wrap 13 is formed in a concave space 12 surrounded by a peripheral wall 11, and the first scroll It comprises an orbiting scroll 20 having a second wrap 21 that can be fitted into the wrap 13, for example a peripheral wall 11 facing the concave space 12 of the fixed scroll 10 and a second wrap 21 located in the central region of the concave space.
The suction port 16 and the discharge port 17 are respectively provided on the sliding surface 14 (bottom surface) of the and the swirl is performed so that the contact point (or the closest contact point) between both wraps functioning as a compression chamber gradually moves toward the center. Fixed scroll 10 with fixed radius 10
By revolving around the center of the wrap 21, the gas introduced into the concave space 12 from the suction port is wrapped around the winding end end 21b (outer end) of the second wrap 13, Taken into the enclosed space 22 formed by
The orbiting scroll 20 is moved toward the center while gradually reducing its volume along with the orbital movement of the orbiting scroll 20.
A scroll-type compressor is known in which the gas in 22 is electrically connected to the discharge port 17 when the pressure in the gas is increased, and the high-pressure gas can be discharged to the outside through the discharge port 17.

In this type of compressor, a groove portion 2 having a rectangular cross section is formed in a spiral lap end surface 21a facing the sliding surface 14 of the opposite scroll 10 or 20 (the sliding surface on the orbiting scroll 20 side is not shown). The seal member 1 is fitted into the seal member 1 to improve the sealing performance of the closed space formed between the sliding surface 14 and the wrap 21 via the seal member 1, and preferably the seal member 1 is a belt-shaped self-lubricating material. There is also proposed a device in which the compressor is oil-free by forming the compressor.

And in such an oil-free compressor, FIG. 3 (a)
As shown in Fig. 5, the back pressure introduced from the high pressure side closed space P1 to the seal member bottom surface 1a side through the gap 32 between the groove side walls 2b is used to press the seal member 1 toward the sliding surface 14 side. Is configured to ensure the sealing performance.

Therefore, in order to obtain a smooth pressing force due to the back pressure, it is necessary to secure at least the space 31 between the groove bottom surface 2a and the seal member 1. However, the existence of the space 31 exists in the central region along the spiral direction of the wrap 21. High-pressure air will leak to the outer peripheral side.

In order to eliminate such a defect, as shown in FIG. 2 (g),
Provided on the seal member bottom surface 1a side facing the groove portion 2 is a scale-like projection 51 formed by cutting in a multi-step manner along the longitudinal direction, and the projection 51 blocks the conduction of the gap 31 in the spiral direction of the wrap 21, There is a technology that prevents leakage of high-pressure gas. (Japanese Patent Laid-Open No. 63-61701) "Problem to be Solved by the Invention" However, since the space between the seal member 1 and the groove portion 2 has a space 31 on the bottom surface side and a space 32 on the side wall side, the side wall side. Will be leaked.

Therefore, attempts have been made to minimize the leakage by reducing the clearance between the seal member 1 and the groove portion 2 on the side wall side. However, the seal member 1 made of a self-lubricating material is more heat-resistant than the wrap 21. Since the expansion coefficient is large, the scroll compressor that compresses gas while gradually reducing the volume of the closed space P1 from the outer peripheral side toward the central area side is more central than the outer peripheral area of the lap 21. Since the temperature of the side wall becomes higher, in other words, the temperature of the wrap 21 is different along the spiral direction, for example, if the gap 32 of the side wall surface is set in accordance with the outer peripheral side of the lap 21, the seal member 1 located on the central region side will have the groove 2 side. For example, the seal member 1 adheres to the wall surface, and as a result, the sliding resistance against the vertical movement of the tip seal is significantly increased.
Even if a back pressure is applied to the back side of, the smooth sealing performance cannot be obtained.

On the other hand, if the gap 32 on the side wall surface is set in conformity with the central area of the wrap 21, the gap 32 on the outer peripheral side becomes larger than necessary, conversely, resulting in a large amount of gas leakage flowing through the side wall surface of the groove 2. In addition to the above, the seal member 1 may be inclined as shown in FIG. 3 and abnormal wear may occur due to a change in the surface pressure.

In order to eliminate such a defect, the applicant of the present invention, for example, as shown in FIG. 2 (f), corresponds to the formation position of the multi-step projection 52 formed on the seal member bottom surface 1a side, and the seal member 1
A scroll compressor in which a similar notch projection 53 is formed on the high-pressure side wall surface of so that the leakage in the spiral direction is completely blocked was also examined (hereinafter referred to as the comparative invention). Since the leakage of the two voids 31 and 32 is completely blocked on both the bottom surface 2a side and the side wall surface 2b side, the following problems occur.

That is, the back pressure of the seal member 1, in other words, the pressing force is determined by the pressure difference between the adjacent closed spaces partitioned by the seal member 1, but in the case of a scroll compressor, it is shown in FIG. The first closed space P0 communicating with the discharge port 17 at the same pressure as the discharge pressure, and the second high pressure state second space
A closed space P1, a low pressure side closed space P2 in a compressed state, and a normal pressure closed space P3 on the outside thereof, and a number of spaces with different pressures exist, so P0 (discharge pressure) >> P1 ( High pressure)> P2 (low pressure)> P3 (normal pressure), and there is a large variation in the pressure difference between adjacent sealed spaces, so if the projections 52, 53 are completely cut off at intervals as described above. The pressing force (contact pressure) of the seal member 1 at each interval between the projections 52 and 53 greatly varies depending on the pressure difference, and as a result, the amount of wear of the seal member 1 varies at each projection interval, resulting in durability. As a result, it becomes difficult to ensure smooth sealing performance over a long period of time.

In view of the drawbacks of the prior art, the present invention prevents leaks along the spiral direction of the seal member as much as possible while ensuring smooth sealability of the seal member and improving durability, and significantly improves compression efficiency or expansion efficiency. It aims at providing the scroll fluid machine which aimed at.

"Means for Solving the Problem" The present invention provides a spiral center of the seal member 1 on two adjacent surfaces of the seal member 1 facing the bottom surface of the groove 2 and the side wall surface (generally on the high pressure side). It is similar to the comparative invention in that the protrusion members 5a and 5b which receive the pressure applied from the region side to the outer region side and are elastically pressed against the groove portion 2 side are the same as the comparative invention, but the comparison As shown in FIG. 1 (A), the protrusion formation position on the side of the bottom surface 1a of the seal member and the protrusion position formed on the (high pressure side) side wall surface are not exactly aligned with each other as in the invention. It is characterized in that it is disposed so as to be displaced in the spiral direction.

In this case, it is not necessary to form all the protruding members 5a, 5b by staggering them relative to each other, and if necessary, the plurality of protruding members 5a, 5b that have been displaced, or the sealing member 1. The projection member 5a on the other surface side on the outer peripheral side end side of 1
At least one or more protrusion members 5a 'may be provided that match the formation position of the.

Further, it is not necessary to set the arrangement intervals of the projecting members 5a and 5b at equal intervals, and it may be preferable to set the intervals so that the projection members 5a and 5b become larger successively as they progress from the central region to the outer peripheral region in the spiral direction.

[Operation] According to the technical means, as in the comparative invention, the back pressure is applied to the seal member 1 in a state in which the leakage along the spiral direction of the seal member 1 is completely blocked at intervals of the protrusions 52 and 53. Rather than applying the voltage, as shown in FIG.
Since a and 5b are arranged with the positions displaced for each adjacent surface,
The high-pressure air on the bottom surface 1a side in the central region of the seal member 1 can be leaked in a zigzag manner while alternately moving each surface along the spiral direction, and the labyrinth effect can be maintained to maintain an incompletely sealed state.

As a result, it is possible to make the leakage of the high pressure air in the central region to the outer peripheral side substantially close to zero, and since the high pressure air moves to the low pressure side at a minute speed, it becomes more spiral in the central region side. Even if there are many sealed spaces having different pressures along it, it is possible to smooth the back pressure imbalance for each interval between the protrusions 5a and 5b.

Further, the seal member 1 and the groove portion 2 of the high pressure side wall surface 1b on the side where the back pressure is applied are not in pressure contact with each other by direct surface contact as in the prior art, but elastically via the protrusion member 5b and Since the pressure contact is made substantially in line contact at predetermined intervals, the sliding resistance in the pressing direction on the sliding surface 14 side of the seal member 1 is reduced, and the seal member 1 slides with good followability. The moving surface 14 can be pressure-contacted, and the sealing performance is improved.

Further, as shown in FIG. 3 (b), the protrusion members 5a, 5b provided on the two adjacent surfaces are provided with elastic force, and
Since 5a and 5b can be freely expanded corresponding to the pressure on the high pressure side, even if the fitting accuracy of the groove portion 2 in the width direction and the depth direction is incorrect, in other words, the dimensional accuracy is rough. Even if it is set to, it is possible to absorb this and press it with high precision.

Further, the fact that the projecting members 5a, 5b can be freely expanded by the pressure receiving force means that the seal member 1 is inclined and pressure-welded even if the clearance of the groove gap 31 on the side wall surface side is formed with a margin. By doing so, abnormal wear and the like due to the change in the surface pressure can be completely prevented, and conversely, the clearance can be set with a margin in consideration of the thermal expansion of the seal member 1, so that the design flexibility and The degree of freedom in processing is greatly improved.

Further, even if the tip seal wears due to long-term operation, the elasticity of the protrusion member 5a can reduce the performance degradation and improve the life of the tip seal itself.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be exemplarily described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention only thereto, but merely illustrative examples. Nothing more than.

FIG. 1 is an embodiment showing the basic structure of the present invention, in which 21a is a wrap end surface facing the opposite scroll sliding surface 14, and a groove portion 2 having a rectangular cross section along the longitudinal center line in the spiral direction.
Is recessed. The seal member 1 fitted in the groove portion 2 is formed of a self-lubricating resin material in a band shape, and wedge-shaped notch projections are alternately formed on adjacent wall surfaces of the seal member 1 along the longitudinal direction. The notch projection is configured to be deformable in the expansion direction by receiving the pressure applied from the central region side toward the outer region side in the spiral direction.

Next, the case where the seal member 1 according to the present embodiment is mounted (a) and the case where the seal member 1 having the cut projections 52, 53 at the same cut position on the adjacent two surfaces as in the comparative invention is mounted. Referring to FIG. 4 (A) for the changes in the surface pressure in (b) and in the case where the seal member is installed without any notch (c), the rotation angle θ: 0 ° In the case of ×, the pressure difference between the enclosed spaces is P1 <
At P0 (discharge pressure) and θ: 90 °, the pressure difference is P1 ＝ P1 ′
Below (high pressure) θ: P1 = P1 'at 180 °, P1 at θ = 270 °
<P0, the surface pressure change is as shown in FIG. 4 (B). Therefore, as can be understood from FIG. 4 (B), in the comparative invention (b) in which the leakage is completely cut off at intervals of the cut projections 5a, 5b, the pressure difference between the adjacent sealed spaces P1, P2 corresponds to As a result, the surface pressure fluctuates drastically. On the other hand, in the case of (c) where there is no notch protrusion, complete leakage occurs and the surface pressure decreases. However, according to this Example (a), the surface pressure can be smoothed and maintained at a high pressure, and it can be understood that the function and effect of the present invention are smoothly achieved.

In addition, in the present invention, it is not necessary to form all the notch protrusions 5a and 5b by staggering them as shown in the embodiment (FIG. 2 (a)). When the applied pressure is larger than that on the side wall surface, FIG. 2 (b)
As shown in Fig. 5, the side wall surface side notch protrusions 5b may be formed in each of a plurality of intervals of the protrusions 5a at the bottom face side, and it is not necessary to set the arrangement intervals of the notch protrusions 5a and 5b at equal intervals. In order to balance the surface pressures of the high pressure central region side and the low pressure outer peripheral side, as shown in FIG. 2 (c), the intervals of the protrusions 5a, 5b are changed from the spiral direction central region to the outer peripheral region. You may set so that it may become large geometrically in order.

Further, it is not necessary to completely shift all the protrusions 5a, 5b from each other, and as shown in FIG. 2 (d), at least the (outer periphery) end side of the seal member 1 is prevented from leaking to the open space side. In order to do so, it is also possible to form the notch protrusion 5a ′ in conformity with the formation position of the notch protrusion 5b on the other surface side,
Also, as shown in FIG. 2 (e), for each group of the plurality of position-shifted notch protrusions 5a, 5b corresponding to one revolution of the seal member 1, a notch protrusion 5c matching the notch protrusion 5b on the other surface side is provided. By providing it, the leakage prevention effect can be further improved without reducing the effect of the present invention, and thereby the compression efficiency can be improved.

[Advantages of the Invention] As described above, according to the present invention, leakage of the seal member along the spiral direction is prevented as much as possible while ensuring smooth sealability of the seal member fitted to the wrap end face and improving durability. However, it is possible to provide a scroll fluid machine with a significantly improved compression efficiency or expansion efficiency. It is possible to provide an oil-free scroll compressor having various effects such as the above and having excellent durability for the first time in the present invention, and its practical value is extremely large.

Further, although the compressor has been described in detail in the above embodiment, the invention is not limited to this and can be applied to an expander and a vacuum pump.

[Brief description of drawings]

FIG. 1 is a perspective view showing a basic structure of the present invention. FIG. 1A shows a seal member, and FIG. 1B shows a wrap end face shape in which the seal member is fitted. FIG. 2 shows each embodiment (a) to (e) of the present invention.
FIG. 3A is a development view showing the protrusion forming positions on the side wall surface and the bottom surface of the seal member in the prior art (g) and the studied invention (f), and FIG. 3 (a) shows the pressure contact state on the sliding surface side of the present invention and the prior art. FIG. 4 is an operation diagram showing the same, and FIG. 6B is an operation diagram showing a pressure receiving state of the protrusion according to the present invention. 4 (A) and (B) are action diagrams showing the state of surface pressure change of the prior art, the present embodiment and the comparative invention at each rotation angle position of the scroll, and the present invention is applied to FIGS. 5 (A) and (B). Shows a scroll compressor.

Claims (4)

[Claims] 1. A seal member is inserted into a groove portion having a rectangular cross section on an end surface of a spiral lap facing a sliding surface of a mating scroll, and the seal member is interposed between the sliding surface and the lap. In a scroll type fluid machine for sealing a surrounding space to be formed, in the two adjacent surfaces of a seal member facing a bottom surface and a side wall surface of the groove portion, applied from the central area side in the spiral direction of the seal member toward the outer peripheral side. Is provided with a protrusion member that is elastically pressed against the groove portion side by receiving the pressure applied to the groove portion, and at least the protrusion member formed on one surface side of the seal member in the spiral direction with respect to the protrusion member formed on the other surface side. Scroll fluid machine characterized by being displaced along the line 2. The formation position of the projection member on the other surface side is matched with each of the plurality of projection member groups displaced from the projection member on the other surface side or on the outer peripheral side end side of the seal member. The scroll fluid machine according to claim 1, wherein at least one or more protruding members are provided. 3. The scroll fluid machine according to claim 1), wherein the interval between the projecting members is set so as to gradually increase from the central region toward the outer peripheral region in the spiral direction. 4. The seal member is formed of a belt-shaped self-lubricating material, and wedge-shaped notches are alternately formed in adjacent wall surfaces of the self-lubricating material along a longitudinal direction, and the notches are formed from the central region side in the spiral direction. The scroll fluid machine according to claim 1, wherein the scroll fluid machine is configured to be deformable in a spreading direction by receiving a pressure applied toward the outer region side.