CN107165829B

CN107165829B - Compression mechanism and compressor with same

Info

Publication number: CN107165829B
Application number: CN201710632136.8A
Authority: CN
Inventors: 林少坤; 陈振华
Original assignee: Guangdong Meizhi Compressor Co Ltd
Current assignee: Guangdong Meizhi Compressor Co Ltd
Priority date: 2017-07-28
Filing date: 2017-07-28
Publication date: 2020-01-17
Anticipated expiration: 2037-07-28
Also published as: CN107165829A

Abstract

The invention discloses a compression mechanism and a compressor with the same. The muffler encircles and prescribes a limit to the amortization chamber in the periphery of cylinder and muffler and the periphery wall of cylinder, and gas vent and amortization chamber intercommunication are equipped with the amortization hole on the muffler, and the amortization hole communicates with the amortization chamber, and the muffler has and dodges the mouth, and the bellying is worn to locate and dodges the mouth, and the induction port is located the amortization chamber outside. According to the compression mechanism, the silencer surrounds the periphery of the cylinder, so that the thickness of the compression mechanism in the axial direction of the cylinder can be reduced, the clearance volume of the compression mechanism is reduced, exhaust airflow can deviate from the balance block of the rotor, and the influence of the exhaust airflow on a motor heat jacket can be avoided.

Description

Compression mechanism and compressor with same

Technical Field

The invention relates to the technical field of compressors, in particular to a compression mechanism and a compressor with the same.

Background

In the related art, the exhaust passage of the compressor is passed through the cylinder oblique cut, enters the exhaust port of the bearing, and then enters the muffler at the upper end. On one hand, the clearance volume comprises a bearing exhaust port and a cylinder inclined notch, and the clearance volume is large; on the other hand, the muffler is in the upper end, has influenced the height of motor thermal jacket, and simultaneously, the exhaust outlet is just to main balancing piece, and the velocity of flow height leads to the windage big. In addition, high exhaust temperature directly passes through the air gap of the motor, and high-temperature gas influences the heat dissipation and the motor efficiency of the motor.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a compression mechanism which has the advantages of simple structure and high space utilization rate.

The invention also provides a compressor comprising the compression mechanism.

A compression mechanism according to an embodiment of the present invention includes: the cylinder is provided with a compression cavity, an air suction port and an air exhaust port, the air suction port and the air exhaust port are communicated with the compression cavity, a bulge part is arranged on the peripheral wall of the cylinder, the air suction port is arranged on the bulge part, the air exhaust port is arranged on the cylinder, and the air exhaust port is spaced from the bulge part; the silencer, the muffler encircles the periphery of cylinder just the silencer with the amortization chamber is injectd to the periphery wall of cylinder, the gas vent with amortization chamber intercommunication, be equipped with the bloop on the silencer, the bloop with amortization chamber intercommunication, the silencer has and dodges the mouth, the bellying wears to locate dodge the mouth, the induction port is located the amortization chamber outside.

According to the compression mechanism provided by the embodiment of the invention, the silencer surrounds the periphery of the cylinder, and the cylinder is directly communicated with the silencer, so that the thickness of the compression mechanism in the axial direction of the cylinder can be reduced, and an exhaust port can be prevented from being formed in a bearing, so that the clearance volume of the compression mechanism can be reduced. In addition, the muffling hole that the muffler was equipped with is kept away from the axis of cylinder, and the balancing piece of exhaust air current skew rotor to can avoid the influence of exhaust air current to the motor thermal jacket, and then can reduce the distance between compressing mechanism and the motor, the miniaturized design of the compressor of being convenient for.

According to some embodiments of the invention, the sound-deadening chamber is annular. Therefore, the silencer can be conveniently surrounded on the peripheral wall of the cylinder, airflow flows in the annular silencer, resistance is small, flowing is smooth, and noise is low.

According to still further embodiments of the present invention, the muffling holes are plural, and the plural muffling holes extend in a circumferential direction of the cylinder. Therefore, the efficiency of the exhaust airflow flowing out of the silencer can be improved, and the conditions that the airflow is blocked in the silencing cavity and floc flow noise is formed are avoided.

According to some examples of this invention, the muffler comprises: a first side plate surrounding a side wall of the cylinder, the first side plate being spaced apart from the cylinder; a second side plate connected between the cylinder and the first side plate; and the third side plate and the second side plate are spaced apart along the axial direction of the cylinder, the third side plate is connected between the cylinder and the first side plate, and the sound attenuation cavity is limited by the side walls of the first side plate, the second side plate, the third side plate and the cylinder. Therefore, the silencing cavity can be constructed by utilizing the side wall of the cylinder, and the structure is simple and convenient to realize.

Further, the muffling hole is formed in at least one of the second side plate and the third side plate. Therefore, the direction of the airflow flowing out of the exhaust port in the radial direction is changed after the airflow passes through the silencing cavity, and the airflow is discharged from the axis direction of the cylinder, so that the change of an exhaust channel can be increased, the airflow speed is reduced, and the airflow noise can be reduced.

Still further, the muffling hole is located at a position close to the first side plate. Therefore, the exhaust airflow deviates from the balance block of the motor rotor, so that the influence of the exhaust airflow on the motor thermal sleeve can be avoided, the exhaust airflow can not be over against the balance block of the motor rotor, the influence of the airflow formed by high-speed rotation of the rotor on the exhaust airflow can be reduced, and the wind resistance of the exhaust airflow is reduced.

According to some embodiments of the invention, an outer surface of the protrusion is sealingly connected to a periphery of the avoidance port.

According to some examples of the invention, the suction port is provided on an end surface of a free end of the boss portion. From this, can prolong the length of breathing in the passageway to can provide enough space for the connection of intake pipe on the reservoir, the setting of the sealing member of also being convenient for moreover, thereby can improve the leakproofness between intake pipe and the compression chamber.

According to still further embodiments of the invention, further comprising: the exhaust valve plate is positioned in the exhaust port; and the lift limiter is positioned at a position close to the exhaust valve plate so as to limit the stroke of the exhaust valve plate. Therefore, the air flow can be controlled to be discharged, and the situation that explosion occurs due to overhigh air pressure in the compression cavity is avoided.

A compressor according to an embodiment of the present invention includes the compression mechanism according to any one of the above.

According to the compressor provided by the embodiment of the invention, the silencer surrounds the periphery of the cylinder, and the cylinder is directly communicated with the silencer, so that the thickness of the compression mechanism in the axial direction of the cylinder can be reduced, and an exhaust port can be prevented from being formed in a bearing, so that the clearance volume of the compression mechanism can be reduced. In addition, the muffling hole that the muffler was equipped with is kept away from the axis of cylinder, and the balancing piece of exhaust air current skew rotor to can avoid the influence of exhaust air current to the motor thermal jacket, and then can reduce the distance between compressing mechanism and the motor, the miniaturized design of the compressor of being convenient for.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a partial schematic structural view of a compression mechanism according to an embodiment of the present invention;

FIG. 2 is a partial schematic structural view of a compression mechanism according to an embodiment of the present invention;

FIG. 3 is a schematic view of a partial cross-sectional configuration of a compression mechanism according to an embodiment of the present invention;

FIG. 4 is a schematic structural view of a cylinder according to an embodiment of the present invention;

FIG. 5 is a schematic structural view of a cylinder according to an embodiment of the present invention;

fig. 6 is a schematic structural view of a compressor according to an embodiment of the present invention.

Reference numerals:

the compressor (1) is provided with a compressor,

the compression mechanism (10) is provided with a compression mechanism,

cylinder 100, compression chamber 110, suction port 120, suction passage 121, discharge port 130, discharge passage 131, boss 140, recess 150, screw hole 160,

the muffler 200, the muffling chamber 210, the muffling hole 220, the escape opening 230, the first side plate 240, the second side plate 250, the third side plate 260,

an exhaust valve plate 300, a lift stopper 400, a piston 500, a slide plate 600,

housing 20, chamber 201, motor 30, crankshaft 40, upper bearing 50, lower bearing 60, reservoir 70,

an intake pipe 700.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "length", "thickness", "upper", "lower", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

A compression mechanism 10 according to an embodiment of the present invention is described below with reference to fig. 1 to 6.

As shown in fig. 1 to 6, a compression mechanism 10 according to an embodiment of the present invention includes: a cylinder 100, a muffler 200, an exhaust valve sheet 300, and a lift stopper 400.

Specifically, as shown in fig. 1 to 4, the cylinder 100 has a compression chamber 110, an intake port 120, and an exhaust port 130, and the intake port 120 and the exhaust port 130 communicate with the compression chamber 110. The cylinder 100 has a boss 140 on a peripheral wall thereof, the suction port 120 is provided in the boss 140, the discharge port 130 is provided in the cylinder 100 and the discharge port 130 is spaced apart from the boss 140. The muffler 200 surrounds the periphery of the cylinder 100, the muffler 200 defines a silencing cavity 210 with the peripheral wall of the cylinder 100, the exhaust port 130 is communicated with the silencing cavity 210, a silencing hole 220 is formed in the muffler 200, the silencing hole 220 is communicated with the silencing cavity 210, the muffler 200 is provided with a avoiding opening 230, the protruding portion 140 penetrates through the avoiding opening 230, and the suction port 120 is located outside the silencing cavity 210.

It will be appreciated that, as shown in FIGS. 1-4, cylinder 100 has a compression chamber 110, and piston 500, slide 600, etc. are positioned within compression chamber 110 for assisting crankshaft 40 in compressing gas. Alternatively, the cylinder 100 may be formed in a ring shape, and the inner circumferential wall of the cylinder 100 is formed as the compression chamber 110. A boss 140 is provided on a radial direction of the cylinder 100, a suction port 120 is provided on a circumferential wall of the boss 140, and the boss 140 has a suction passage 121, and the suction passage 121 is located between the suction port 120 and the compression chamber 110 to communicate the suction port 120 with the compression chamber 110.

As shown in fig. 1 to 3, the muffler 200 has an avoiding opening 230, the muffler 200 is sleeved on the outer circumferential wall of the cylinder 100, the boss 140 of the cylinder 100 can be embedded at the avoiding opening 230, and the inner circumferential wall of the muffler 200 and the side wall of the cylinder 100 can define the muffling chamber 210. The cylinder 100 is provided with an exhaust port 130, an exhaust passage 131 is located between the exhaust port 130 and the compression chamber 110 to communicate the compression chamber 110 with the exhaust port 130, the exhaust port 130 faces the muffling chamber 210, and the cylinder 100 is provided with the exhaust passage 131.

According to the compression mechanism 10 of the embodiment of the present invention, the muffler 200 is disposed around the outer circumferential wall of the cylinder 100, and the cylinder 100 is directly communicated with the muffler 200, so that the thickness of the compression mechanism 10 in the axial direction of the cylinder 100 can be reduced, and the exhaust port 130 can be prevented from being formed in the bearing, thereby reducing the clearance volume of the compression mechanism 10. In addition, the muffling hole 220 of the muffler 200 is far away from the axis of the cylinder 100, and the exhaust airflow deviates from the balance weight of the rotor of the motor 30, so that the influence of the exhaust airflow on the heat jacket of the motor 30 can be avoided, the distance between the compression mechanism 10 and the motor 30 can be further reduced, and the miniaturization design of the compressor 1 is facilitated.

As shown in fig. 1 to 4, according to an embodiment of the present invention, a groove 150 is formed on an inner sidewall of the cylinder 100, a spring plate (not shown) may be disposed in the groove 150, one end of the spring plate is fixed in the groove 150, and the other end of the spring plate is connected to the sliding vane 600, so that the sliding vane 600 may be abutted against the piston 500 in accordance with a change of a rotational position of the piston 500. In one embodiment of the present invention, screw holes 160 may be formed on both upper and lower (upper and lower as shown in fig. 1) end surfaces of the cylinder 100, and the cylinder 100 may be connected to other components of the compressor 1, such as the upper bearing 50 and the lower bearing 60, by screws or other fastening assemblies. Further, there may be a plurality of screw holes 160, and the plurality of screw holes 160 are arranged at even intervals along the circumferential direction of the cylinder 100.

In some examples of the invention, the thickness of the cylinder 100 is greater than the thickness of the muffler 200 in the thickness direction of the cylinder 100, i.e., the up-down direction as shown in fig. 1. In one embodiment of the present invention, the cylinder 100 is a low carbon steel member having high strength and smooth surface, which can reduce the resistance of the exhaust gas flow. In one example of the present invention, the muffler 200 may be attached to the cylinder 100 by welding or fastening. Optionally, the wall thickness of the muffler 200 may range from: 0.5-2mm, the aperture range of the muffling hole 220 can be: phi 1-phi 10 mm.

As shown in fig. 1-3, the sound-attenuating chamber 210 may be annular in shape, according to some embodiments of the present invention. It can be understood that the outer side wall of the muffler 200 is formed in a ring shape, so that the muffler 200 can be easily surrounded on the outer circumferential wall of the cylinder 100, and the gas flow flows in the ring-shaped muffler 200, and thus the resistance is small, the flow is smooth, and the noise is small. Further, the silencer 200 may be cut from stamped or "n" shaped thin walled steel tubing.

As shown in fig. 1 and 3, according to further embodiments of the present invention, the muffling hole 220 may be a plurality of holes, and the plurality of muffling holes 220 extend in the circumferential direction of the cylinder 100. It is understood that at least two muffling holes 220 are provided in the muffler 200, and the plurality of muffling holes 220 are spaced apart in the circumferential direction of the cylinder 100. This increases the efficiency of the exhaust gas stream exiting muffler 200, thereby avoiding the flow of gas from becoming clogged in muffler chamber 210 and causing floc flow noise.

As shown in fig. 1-3, according to some examples of this invention, the muffler 200 includes a first side plate 240, a second side plate 250, and a third side plate 260. Wherein the first side plate 240 surrounds the side wall of the cylinder 100, the first side plate 240 is spaced apart from the cylinder 100, the second side plate 250 is connected between the cylinder 100 and the first side plate 240, the third side plate 260 and the second side plate 250 are spaced apart along the axial direction of the cylinder 100, the third side plate 260 is connected between the cylinder 100 and the first side plate 240, the second side plate 250, the third side plate 260 and the side wall of the cylinder 100 define the muffling cavity 210.

It is to be understood that, as shown in fig. 1 to 3, the first side plate 240 is opposed to a side wall of the cylinder 100 and the first side plate 240 is spaced apart from the side wall of the cylinder 100 in a radial direction of the cylinder 100, and preferably, the first side plate 240 extends in a circumferential direction of the cylinder 100. The second side plate 250 and the third side plate 260 are located between the cylinder 100 and the first side plate 240, the third side plate 260 and the second side plate 250 are spaced apart along the axial direction of the cylinder 100, two ends of the second side plate 250 are respectively connected with the side wall of the cylinder 100 and the first side plate 240, two ends of the third side plate 260 are respectively connected with the side wall of the cylinder 100 and the first side plate 240, and the side walls of the first side plate 240, the second side plate 250, the third side plate 260 and the cylinder 100 jointly define the sound attenuation cavity 210. Therefore, the silencing cavity 210 can be constructed by utilizing the side wall of the cylinder 100, and the structure is simple and convenient to realize.

Further, as shown in fig. 1 and 3, at least one of the second and

third side plates

250 and 260 is provided with a sound-deadening hole 220. It is understood that the second side plate 250 may be provided with the muffling hole 220, and the third side plate 260 may be provided with the muffling hole 220. Therefore, the muffling holes 220 can be disposed at the upper end and/or the lower end (upper and lower ends as shown in fig. 1) of the muffler 200, and the air flow flowing out from the radial exhaust port 130 changes direction after passing through the muffling chamber 210 and is exhausted from the axial direction of the cylinder 100, so that the variation of the exhaust channel 131 can be increased, the air flow velocity can be slowed, and the air flow noise can be reduced. Preferably, the muffling hole 220 is formed on the third side plate 260 close to the oil sump of the compressor 1, so that the high-temperature exhaust air can exchange heat with the low-temperature oil sump through heat exchange, thereby reducing the exhaust temperature, reducing the influence of exhaust on the heat dissipation of the motor 30, and improving the efficiency of the motor 30.

Further, as shown in fig. 1 and 3, the muffling hole 220 is located close to the first side plate 240. It is understood that the muffling aperture 220 is located at an edge location of the second side plate 250 and/or the third side plate 260. Therefore, the exhaust airflow deviates from the balance block of the rotor of the motor 30, so that the influence of the exhaust airflow on the heat jacket of the motor 30 can be avoided, and the exhaust airflow can not be over against the balance block of the rotor of the motor 30, so that the influence of the airflow formed by the high-speed rotation of the rotor on the exhaust airflow can be reduced, the wind resistance of the exhaust airflow is reduced, and the exhaust airflow can flow out of the compressor 1. In one embodiment of the present invention, the center axis of the muffling hole 220 is located between the stator of the motor 30 and the inner peripheral wall of the housing 20 of the compressor 1.

As shown in fig. 1-3, according to some embodiments of the invention, the outer surface of the projection 140 is sealingly connected to the perimeter of the bypass opening 230. It will be appreciated that the outer peripheral wall of the boss 140 abuts and is in close contact with the inner peripheral edge of the bypass opening 230.

As shown in fig. 1 to 4, according to some examples of the present invention, the suction port 120 is provided on an end surface of the free end of the boss 140. It should be noted that the "free end" mentioned here is an end of the boss 140 away from the central axis of the cylinder 100. Accordingly, the length of the suction passage 121 can be extended to provide a sufficient space for the connection of the intake pipe 700 to the reservoir 70, and the arrangement of the sealing member can be facilitated, so that the sealability between the intake pipe and the compression chamber 110 can be improved.

As shown in fig. 5, according to still other embodiments of the present invention, the compression mechanism 10 further includes an exhaust valve sheet 300 and a lift stopper 400, the exhaust valve sheet 300 is positioned in the exhaust port 130, and the lift stopper 400 is positioned adjacent to the exhaust valve sheet 300 to limit the stroke of the exhaust valve sheet 300. It is understood that the discharge valve plate 300 is disposed on the cylinder 100 and adapted to block or open the discharge port 130, thereby controlling the discharge of the air flow, and the lift stopper 400 is disposed on the cylinder 100 and close to the discharge valve plate 300, and the lift stopper 400 can be used to control the opening or closing state of the discharge port 130 of the discharge valve plate 300. Further, the lift stopper 400 and the cylinder 100 may be connected by a threaded fastener. In one embodiment of the present invention, the wall thickness at the cylinder 100 where the discharge valve sheet 300 is provided is 1.7mm or more.

As shown in fig. 6, the compressor 1 according to the embodiment of the present invention includes a housing 20, a motor 30, a crankshaft 40, an upper bearing 50, a lower bearing 60, and the compression mechanism 10 according to the above.

Specifically, as shown in fig. 6, the housing 20 is formed with a chamber 201, and the motor 30, the crankshaft 40, the upper bearing 50, the lower bearing 60, and the compression mechanism 10 are all located within the chamber 201. The motor 30 is disposed on the compressor 1, the crankshaft 40 is disposed below the compressor 1, one end of the crankshaft 40 is connected to the motor 30, the other end of the crankshaft 40 extends toward the length direction (i.e., the up-down direction shown in fig. 6) of the housing 20, the upper bearing 50, the lower bearing 60 and the compression mechanism 10 are all sleeved on the crankshaft 40, the compression mechanism 10 is disposed between the upper bearing 50 and the lower bearing 60, the crankshaft 40 passes through the compression cavity 110 of the cylinder 100, and a portion of the crankshaft 40 located in the compression cavity 110 is provided with the piston 500.

According to the compressor 1 of the embodiment of the present invention, the muffler 200 is disposed around the outer periphery of the cylinder 100, and the cylinder 100 is directly communicated with the muffler 200, so that the thickness of the compression mechanism 10 in the axial direction of the cylinder 100 can be reduced, and the exhaust port 130 can be prevented from being formed in the bearing, thereby reducing the clearance volume of the compression mechanism 10. In addition, the muffling hole 220 of the muffler 200 is far away from the axis of the cylinder 100, and the exhaust airflow deviates from the balance weight of the rotor, so that the influence of the exhaust airflow on the heat jacket of the motor 30 can be avoided, the distance between the compression mechanism 10 and the motor 30 can be further reduced, and the miniaturization design of the compressor 1 is facilitated.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A compression mechanism of a compressor, comprising:

the cylinder is provided with a compression cavity, an air suction port and an air exhaust port, the air suction port and the air exhaust port are communicated with the compression cavity, a bulge part is arranged on the peripheral wall of the cylinder, the air suction port is arranged on the bulge part, the air exhaust port is arranged on the cylinder, and the air exhaust port is spaced from the bulge part;

the silencer, the muffler encircles the periphery of cylinder just the silencer with the amortization chamber is injectd to the periphery wall of cylinder, the gas vent with amortization chamber intercommunication, be equipped with the bloop on the silencer, the bloop with amortization chamber intercommunication, the silencer has and dodges the mouth, the bellying wears to locate dodge the mouth, the induction port is located the amortization chamber outside.

2. The compression mechanism of a compressor, as set forth in claim 1, wherein said muffling chamber is annular.

3. The compressing mechanism of compressor as set forth in claim 1, wherein said muffling hole is plural, and plural said muffling holes extend in a circumferential direction of said cylinder.

4. The compression mechanism of a compressor according to claim 1, wherein said muffler includes:

a first side plate surrounding a side wall of the cylinder, the first side plate being spaced apart from the cylinder;

a second side plate connected between the cylinder and the first side plate; and

the third side plate and the second side plate are spaced apart along the axis direction of the cylinder, the third side plate is connected between the cylinder and the first side plate, and the sound attenuation cavity is limited by the side walls of the first side plate, the second side plate, the third side plate and the cylinder.

5. The compressing mechanism of compressor as set forth in claim 4, wherein said muffling hole is provided on at least one of said second side plate and said third side plate.

6. The compression mechanism of a compressor according to claim 5, wherein said muffling hole is located at a position close to said first side plate.

7. The compression mechanism of a compressor according to claim 1, wherein an outer surface of the boss portion is sealingly connected to a periphery of the avoidance port.

8. The compression mechanism of a compressor according to claim 1, wherein said suction port is provided on an end surface of a free end of said boss portion.

9. The compression mechanism of a compressor according to claim 1, further comprising:

the exhaust valve plate is positioned in the exhaust port; and

the lift limiter is positioned at a position close to the exhaust valve plate so as to limit the stroke of the exhaust valve plate.

10. A compressor characterized by comprising a compression mechanism of the compressor according to any one of claims 1 to 9.