JPH07150924A - Oil separator for blow-by gas - Google Patents

Abstract

PURPOSE:To provide an oil separator for blow-by gas, having high recovery of lubricating oil. CONSTITUTION:An intake disc 50 for introducing blow-by gas to a cam shaft 3 and an outlet disc 6'0 connected to a blow-by gas passage 8 are connected to each other, and a bulkhead 11 for forming a first separating chamber 51 and a second separating chamber 52 is provided between both discs, and oil discharging ports 14, 15 are opened on the outer peripheries of the first separating chamber 51 and the second separating chamber 52, and a communication port 16 is opened on the bulkhead 11 so as to be offset to an intake port 10 and a takeout port 21.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to improvements in blow-by gas oil separators.

[0002]

2. Description of the Related Art In an engine in which blow-by gas blown from a combustion chamber into a crank chamber or a valve operating chamber on a cylinder head is recirculated to an intake system, lubricating oil must be prevented from being taken away together with the blow-by gas. .

An example of a conventional blow-by gas oil separator is shown in FIG. 6 (Japanese Patent Application Laid-Open No. 57-57).
2411 gazette).

To explain this, the camshaft 7
The rotating disk 70 is connected to the front end of the rotating disk 70.
A fixed disk 71 is provided adjacent to the fixed disk 71, and a discharge port 72 opened in the fixed disk 71 communicates with an intake pipe via a blow-by gas passage 75.

The blow-by gas passes through the gap 77 between the rotating disk 70 and the fixed disk 71 as shown by the arrow in the figure, and the discharge port 7 is formed.
In the process of flowing into 2, the lubricating oil contained in the blow-by gas is attached to the rotating disk 70, and the attached lubricating oil is scattered to the outside of the gap 77 by the centrifugal force.

[0006]

However, in such a conventional blow-by gas oil separator,
A gap 77 defined between the rotating disk 70 and the fixed disk 71.
Since its cross section extends linearly in the radial direction of rotation, it is difficult to attach the lubricating oil that flows linearly through the gap 77 to the rotating disk 70, and fine oil mist passes through the gap 77 to the discharge port 72. There is a problem that the amount of lubricating oil taken out and taken out increases.

Further, since the lubricating oil discharged to the outside of the gap 77 by the centrifugal force after adhering to the rotary disk 70 faces the blow-by gas flowing toward the center of rotation in the gap 77, the operation in which the recirculation amount of the blow-by gas increases. At the same time, there is a problem in that the lubricating oil discharged to the outside of the gap 77 is pushed back by the flow of the blow-by gas, and the carried-out amount of the lubricating oil increases.

It is an object of the present invention to provide an oil separator for blow-by gas which has a high recovery rate of lubricating oil, focusing on the above problems.

[0009]

The invention according to claim 1 is
An intake disc and an outlet disc are coupled to a rotating shaft to which the rotational force of the engine is transmitted, and a partition wall that defines a first separation chamber and a second separation chamber is provided between the intake disc and the outlet disc. (2) An oil discharge port is opened in the outer peripheral portion of the separation chamber, an intake port for introducing blow-by gas into the second separation chamber is opened in the intake disk, and blow-by gas is introduced into the second separation chamber from the first separation chamber in the partition wall. The communication port is opened, the outlet is opened in the outlet disk for introducing blow-by gas from the second separation chamber into the intake pipe of the engine, and the communication port is rotated in the radial direction or the circumferential direction with respect to the intake and the outlet. Place it offset.

According to a second aspect of the present invention, in the first aspect of the invention, the total opening area of the communication port is formed smaller than the total opening area of the inlet.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described above, the cylindrical portion defining the communication port is projected from the partition wall into the first separation chamber.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the outer peripheral end of the partition wall is folded back toward the outlet disk so as to cover the oil discharge port communicating with the second separation chamber. .

[0013]

In the invention of claim 1, the blow-by gas blown from the combustion chamber to the crank chamber through the gap between the piston and the cylinder is sucked from the oil separator to the intake pipe of the engine through the blow-by gas passage. , Returned to the combustion chamber.

The flow of blow-by gas in the oil separator flows into the first separation chamber from the intake port and collides with the partition wall, and when its speed is converted to the direction of the communication port, the lubricating oil contained in the blow-by gas is The attached lubricating oil adheres to the partition wall, and as the lubricating oil rotates together with the partition wall, it is collected in the outer peripheral direction of the first separation chamber by centrifugal force and is quickly discharged from the oil discharge port into the engine.

Then, when the flow of the blow-by gas flows into the second separation chamber from the communication port and collides with the outlet disk, the velocity of which is converted in the direction of the outlet, the lubricating oil contained in the blow-by gas is The lubricating oil that adheres to the outlet disc is collected in the outer peripheral direction of the second separation chamber by the centrifugal force as it rotates with the outlet disc, and quickly from each oil discharge port to the valve operating chamber and the chain chamber. Is discharged.

In this manner, the blow-by gas flows meandering through the intake port, the communication port, and the outlet port that are arranged offset from each other, so that the partition wall and the outlet disk of the lubricating oil contained in the blow-by gas are flowed. It is possible to reduce the carry-out amount of the lubricating oil by increasing the rate of adhesion to the oil.

Due to the structure in which the lubricating oil adhering to the partition wall rotating with the engine, the outlet disk, etc. is discharged by the centrifugal force, the lubricating oil floating in the blow-by gas increases at the time of high engine rotation, and the lubricating oil in the blow-by gas is increased. The ability to separate the lubricating oil is increased and the recovery rate of the lubricating oil can be maintained.

In the invention of claim 2, the total opening area of the communication port is formed smaller than the total opening area of the inlet at a predetermined ratio, and the flow velocity of the blow-by gas passing through the communication port is blow-by through the inlet. By setting it so that it is higher than the flow velocity of gas at an appropriate ratio, a relatively large oil mist is attached to the partition wall during the process of flowing from the intake port to the second separation chamber, and a relatively small amount that does not adhere to this partition wall. By accelerating the oil mist in the process of flowing it into the second separation chamber from the communication port, it is possible to promote that the oil mist having a small mass adheres to the outlet disk, and the recovery rate of the lubricating oil can be sufficiently increased.

In the invention of claim 3, the lubricating oil contained in the blow-by gas is suppressed by the cylindrical portion projecting from the partition wall to prevent the lubricating oil flowing along the partition wall toward the oil discharge port from flowing into the communication port. It is possible to increase the ratio of the oil discharged from the oil discharge port of the first separation chamber to reduce the carry-out amount of the lubricating oil.

In the invention according to claim 4, the outer peripheral end of the partition wall folded back toward the outlet disk so as to cover the oil discharge port allows the lubricating oil dripping from the cylinder head cover or the like during low speed operation to enter the oil discharge port. This can be prevented, and the carry-out amount of lubricating oil can be reduced.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is an oil separator, 2 is a cylinder head cover, 3 is a camshaft, and 4 is a cylinder head. A valve operating chamber 18 is defined between the cylinder head 4 and the cylinder head cover 2, and a chain chamber 40 is defined between the cylinder head 4 and the chain case 17.

A cam sprocket 5 is connected to the front end of the cam shaft 3 via a semicircular key 13, a chain 6 is wound around the cam sprocket 5, and a rotational force is transmitted from a crank shaft (not shown). The camshaft 3 rotates at half the speed of the crankshaft,
An intake / exhaust valve (not shown) is opened / closed at a predetermined timing.

A connector 7 is fixedly attached to the cylinder head cover 2, and the connector 7 defines a blow-by gas passage 8 communicating with an intake pipe via a pipe (not shown). The connector 7 is arranged coaxially with the camshaft 3.

A flow control valve (PCV valve) (not shown) is provided in the middle of the blow-by gas passage 8. further,
A fresh air introduction passage (not shown) for introducing fresh air into the valve operating chamber 18 as the blow-by gas is recirculated to the intake pipe is provided.

The oil separator 1 is attached to the front end of the cam shaft 3 and functions to separate the lubricating oil contained in the blow-by gas by centrifugal force while rotating together with the cam shaft 3.

The oil separator 1 comprises three disk-shaped intake disks 50 that rotate together with the camshaft 3.
The partition 11 and the outlet disk 60 are provided.

As shown in FIG. 2, the intake disk 5
0 and the partition wall 11 have a hole 22 formed in the center thereof,
It is fastened to the front end of the camshaft 3 via a bolt 12 penetrating the hole 22.

A first separation chamber 51 is defined between the intake disk 50 and the partition wall 11, and a second separation chamber 52 is defined between the partition wall 11 and the outlet disk 60.

In the intake disk 50, blow-by gas from the valve operating chamber 18 and the chain chamber 40 is fed into the first separating chamber 5
The inlet 10 that allows the water to flow in 1 is open. The four intakes 10 are arranged so as to have a constant distance from the center of rotation of the intake disk 50 and have a constant distance from each other in the circumferential direction.

A communication port 16 for communicating the first separation chamber 51 and the second separation chamber 52 is opened in the partition wall 11. The four communication ports 16 are arranged so as to have a constant distance from the center of rotation of the partition wall 11 and to have a constant distance from each other in the circumferential direction. As shown in FIG. 2, the communication port 16 is arranged so as to be farther from the rotation center than the intake ports 10 and to have a constant space with respect to each intake port 10.

The opening diameter of the communication opening 16 is formed smaller than the opening diameter of the intake opening 10, and the total opening area of the communication opening 16 is set smaller than the total opening area of the communication opening 16 by a predetermined ratio. Thereby, the flow velocity of the blow-by gas passing through the communication port 16 is set to be higher than the flow velocity of the blow-by gas passing through the intake port 10 at an appropriate ratio.

An outlet 21 for letting out blow-by gas is opened at the center of the outlet disc 60. The opening edge of the outlet 21 faces the outer periphery of the connector 7 with a slight gap, and guides blow-by gas from the second separation chamber 52 to the blow-by gas passage 8.

The outlet disk 60 has a connector 7
Has a cylindrical portion 61 facing in parallel to the outer periphery of the connector, the seal mechanism 9 is interposed between the connector 7 and the cylindrical portion 61, and airtightness therebetween is ensured. As the seal mechanism 9, an oil seal, a labyrinth seal, a mechanical seal, or the like is used.

An oil discharge port 14 for discharging the lubricating oil from the first separation chamber 51 to the valve operating chamber 18 and the chain chamber 40 is formed between the intake disk 50 and the partition wall 11. The four oil outlets 14 are arranged along the outer peripheral edge of the partition wall 11 at regular intervals.

An oil discharge port 15 for discharging lubricating oil from the second separation chamber 52 to the valve operating chamber 18 and the chain chamber 40 is formed between the partition wall 11 and the outlet disc 60. Four
The two oil outlets 15 are arranged along the outer peripheral edge of the partition wall 11 at regular intervals.

As shown in FIG. 3, each oil discharge port 14,
Reference numeral 15 is defined by curving the intake disc 50 and the outlet disc 60, respectively, and is arranged side by side with the partition wall 11 in between. The intake disk 50, the partition wall 11, and the outlet disk 60 are formed by press molding, respectively, and the outer peripheral end portion of the outlet disk 60 is located between the oil discharge ports 14 and 15, and the outer peripheral end portions of the intake disk 50 and the partition wall 11 are aligned with each other. It is folded back so as to wrap it, and is fixed to each other by spot welding or brazing at the folded back portion.

With the above construction, the operation will be described below.

The blow-by gas blown from the combustion chamber into the crank chamber through the gap between the piston and the cylinder is introduced into the oil separator 1 through the chain chamber 40, the valve operating chamber 18, etc., and the blow-by gas passage from the oil separator 1 is introduced. It is sucked into the intake pipe through 8 and returned to the combustion chamber.

Oil mist is scattered from the crankshaft, the camshaft 3, etc. in the crank chamber, the valve operating chamber 18, etc. of the engine, and particularly when the engine is rotated at a high speed of 4000 rpm or more, the amount of oil supplied is increased and the crankshaft etc. is rotated at a high speed. As a result, the amount of lubricating oil floating in the blow-by gas increases.

As shown by the arrow in FIG. 1, the flow of the blow-by gas in the oil separator 1 flows into the first separation chamber 51 from the intake port 10 and collides with the partition wall 11, the speed of which is in the direction of the communication port 16. Is converted to. At this time, the lubricating oil contained in the blow-by gas adheres to the partition wall 11, and the adhered lubricating oil is collected in the outer peripheral direction of the first separation chamber 51 by centrifugal force as it rotates together with the partition wall 11. It is quickly discharged from the discharge port 14 into the valve operating chamber 18 and the chain chamber 40.

Subsequently, the flow of the blow-by gas in the oil separator 1 is changed to the communication port 16 as shown by the arrow in FIG.
Flows into the second separation chamber 52 from the outlet disk 6
0, and its speed is converted in the direction of the outlet 21. At this time, the lubricating oil contained in the blow-by gas adheres to the outlet disk 60, and the adhered lubricating oil is collected in the outer peripheral direction of the second separation chamber 52 by the centrifugal force as it rotates with the outlet disk 60, From each oil discharge port 15 to the valve operating chamber 18 and the chain chamber 40
It is promptly discharged.

In this way, the blow-by gas meanders through the intake port 10, the communication port 16, and the extraction port 21 arranged offset from each other, thereby partitioning the lubricating oil contained in the blow-by gas. 11, it is possible to increase the ratio of adhering to the outlet disc 60 and the like, and reduce the carry-out amount of the lubricating oil.

Since the oil separator 1 rotates together with the camshaft 3 and discharges the lubricating oil adhering to the partition wall 11, the outlet disc 60, etc. by centrifugal force, a large amount of lubricating oil floats in the blow-by gas at high engine speed. Accordingly, the ability to separate the lubricating oil in the blow-by gas increases, and it is possible to sufficiently suppress the lubricating oil from being taken out to the intake pipe together with the blow-by gas.

The total opening area of the communication port 16 is formed smaller than the total opening area of the intake port 10 by a predetermined ratio, and the communication port 16 is formed.
Since the flow velocity of the blow-by gas passing through the inlet 10 is set to be higher than the flow velocity of the blow-by gas passing through the inlet 10 at a proper ratio, a relatively large oil mist is generated in the process of flowing from the inlet 10 into the second separation chamber 52. By adhering to the partition wall 11 and accelerating the small oil mist that has not adhered to the partition wall 11 from the communication port 16 into the second separation chamber 52, the oil mist having a small mass adheres to the outlet disk 60. And the recovery rate of the lubricating oil can be sufficiently increased.

Due to the structure in which the oil separator 1 is provided at the front end of the camshaft 3, the crankshaft and the camshaft 3 are
The path through which the oil mist scattered from is sucked into the oil separator 1 is lengthened, and the lubricating oil contained in the blow-by gas introduced into the oil separator 1 is reduced, so that the recovery rate of the lubricating oil can be increased.

Next, another embodiment shown in FIGS. 4 and 5 will be described. 1 to 3 are designated by the same reference numerals.

The oil separator 31 is attached to the front end of the idler gear 33, and functions to separate the lubricating oil contained in the blow-by gas by centrifugal force while rotating together with the idler gear 33.

The idler gear 33 is a gear 34 to which the rotational force from the crankshaft is transmitted via the chain 35.
And a gear 41 for transmitting a rotational force to the camshaft via the chain 36, and a cylindrical boss portion 30 connecting the gears 34, 41.

Bolt 39 fastened to cylinder head 4
The support shaft 38 is fitted to the bearing shaft 37, the bearing 37 is fitted to the support shaft 38, and the boss portion 30 of the idler gear 33 is rotatably fitted to the bearing 37.

The oil separator 31 comprises three disk-shaped intake disks 5 which rotate together with the idler gear 33.
0, a partition wall 45, and an outlet disk 60, and the intake disk 50 and the partition wall 45 are fixed to the front end of the boss portion 38 of the idler gear 33 by welding or brazing so as to rotate integrally with the idler gear 33.

A first separation chamber 51 is defined between the intake disk 50 and the partition wall 45, and a second separation chamber 52 is defined between the partition wall 45 and the outlet disk 60.

The intake disc 50 has a chain chamber 4
An inlet 10 for allowing blow-by gas to flow into the first separation chamber 51 from 0 is open. The four intakes 10 are arranged so as to have a constant distance from the center of rotation of the intake disk 50 and have a constant distance from each other in the circumferential direction.

A communication port 16 is formed in the partition wall 45 to connect the first separation chamber 51 and the second separation chamber 52. The four communication ports 16 are arranged so as to have a constant distance from the center of rotation of the partition wall 45 and have a constant distance from each other in the circumferential direction.

The partition wall 45 is a cylindrical portion 4 which defines each communication port 16.
Have 7. Each cylindrical portion 47 projects into the first separation chamber 51 in a cylindrical shape and is arranged parallel to the rotation axis.

The opening diameter of the communication opening 16 is formed smaller than the opening diameter of the intake opening 10, and the total opening area of the communication opening 16 is set smaller than the total opening area of the communication opening 16 by a predetermined ratio.

An outlet 21 through which blow-by gas flows is opened at the center of the outlet disc 60. The opening edge of the outlet 21 faces the outer periphery of the connector 7 with a slight gap, and guides blow-by gas from the second separation chamber 52 to the blow-by gas passage 8.

An oil discharge port 14 for discharging the lubricating oil from the first separation chamber 51 to the chain chamber 40 is formed between the intake disk 50 and the partition wall 45. 4 oil outlets 1
4 are arranged along the outer peripheral edge of the partition wall 45 so as to have a constant distance from each other.

An oil discharge port 15 for discharging the lubricating oil from the second separation chamber 52 to the chain chamber 40 is formed between the partition wall 45 and the outlet disc 60. The four oil outlets 15 are arranged along the outer peripheral edge of the partition wall 45 so as to be spaced apart from each other.

The oil discharge ports 14 and 15 are defined by bending the intake disk 50 and the outlet disk 60, respectively, and are arranged side by side with the partition wall 45 interposed therebetween.

The outer peripheral end portion 46 of the partition wall 45 is folded back over the entire circumference toward the outlet disc 60 side so as to cover each oil discharge port 15.

The intake disc 50, the partition wall 31, and the outlet disc 60 are formed by press molding, and are fixed to each other by spot welding or brazing at the outer peripheral portion located between the oil discharge ports 14 and 15.

With the above construction, the operation will be described below.

The oil separator 31 rotates together with the idler gear 33 at the same speed as the crankshaft.

The flow of blow-by gas in the oil separator 31 flows into the first separation chamber 51 from the intake port 10 and collides with the partition wall 45 as shown by the arrow in FIG. Is converted to. At this time, the lubricating oil contained in the blow-by gas adheres to the partition wall 45, and the adhered lubricating oil is collected in the outer peripheral direction of the first separation chamber 51 by the centrifugal force as it rotates together with the partition wall 45. It is quickly discharged from the discharge port 14 into the valve operating chamber 18 and the chain chamber 40.

Since the cylinder portion 47 that defines each communication port 16 projects from the partition wall 45, the lubricating oil flowing toward the oil discharge port 14 along the partition wall 11 by the cylinder portion 47 allows the communication port 1 to flow.
It is suppressed that the gas flows into No. 6. As a result, the proportion of the lubricating oil contained in the blow-by gas that is discharged from the oil discharge port 14 of the first separation chamber 51 can be increased, and the carry-out amount of the lubricating oil can be reduced.

Subsequently, the flow of the blow-by gas in the oil separator 31 is as shown by the arrow in FIG.
6 flows into the second separation chamber 52 and collides with the outlet disc 60, and the velocity thereof is converted toward the outlet 21. At this time, the lubricating oil contained in the blow-by gas adheres to the outlet disk 60, and the adhered lubricating oil is collected in the outer peripheral direction of the second separation chamber 52 by the centrifugal force as it rotates with the outlet disk 60, From each oil discharge port 15 to the valve operating chamber 18 and the chain chamber 40
It is promptly discharged.

Since the outer peripheral end 46 of the partition wall 45 is folded back toward the outlet disk 60 so as to cover each oil discharge port 15, the lubricating oil dripping from the cylinder head cover or the like during low speed operation is released by the outer peripheral end 46. Intrusion into the outlet 15 is prevented, and the carry-out amount of the lubricating oil can be reduced.

The outer peripheral end of the partition wall 45 may be partially folded back so as to cover each oil discharge port 15.

[0070]

As described above, in the blow-by gas oil separator according to the invention of claim 1, the intake disk and the outlet disk are coupled to the rotary shaft to which the rotational force of the engine is transmitted, and the intake disk and the outlet disk are connected. A partition that defines the first separation chamber and the second separation chamber is provided between the first separation chamber and the second separation chamber, and an oil outlet is opened in the outer periphery of the first separation chamber and the second separation chamber. An inlet is introduced, a partition is provided with a communication port for introducing blow-by gas from the first separation chamber into the second separation chamber, and an outlet disc is provided with blow-by gas from the second separation chamber for introduction into the intake pipe of the engine. Since the outlet is opened and the communication port is arranged offset from the inlet and outlet in the radial direction of rotation or the circumferential direction of rotation, By flowing the gas in a meandering manner through the inlet, communication port, and outlet, the lubricating oil contained in the blow-by gas is encouraged to adhere to the partition wall, outlet disk, etc., and adheres to the partition wall, outlet disk, etc. rotating with the engine. By discharging the lubricating oil by centrifugal force, the recovery rate of the lubricating oil can be maintained even when the engine is rotating at a high speed where the lubricating oil floating in the blow-by gas is large.

According to the second aspect of the present invention, since the total opening area of the communication port is formed smaller than the total opening area of the inlet at a predetermined ratio, a relatively small oil mist that does not adhere to the partition wall is discharged from the communication port to the second By accelerating in the process of flowing into the separation chamber, oil mist with a small mass is promoted to adhere to the outlet disk, and the recovery rate of lubricating oil can be increased.

According to the third aspect of the present invention, the cylindrical portion defining the communication port is projected from the partition wall into the first separation chamber. Therefore, the lubricating oil flowing toward the oil discharge port along the partition wall by the cylindrical portion is communicated with the communication port. It is possible to suppress the inflow of the oil into the oil and increase the recovery rate of the lubricating oil.

According to the fourth aspect of the invention, since the outer peripheral end of the partition wall is folded back toward the outlet disk so as to cover the oil discharge port communicating with the second separation chamber, the outer peripheral end part of the partition wall allows the cylinder head cover or the like to operate at low speed. It is possible to prevent the lubricating oil dripping from entering the oil discharge port, and to improve the recovery rate of the lubricating oil.

[Brief description of drawings]

FIG. 1 is a sectional view of an engine showing an embodiment of the present invention.

FIG. 2 is a front view of the oil separator.

FIG. 3 is a plan view of the oil separator.

FIG. 4 is a sectional view of an engine showing another embodiment.

FIG. 5 is a front view of the oil separator.

FIG. 6 is a sectional view of an engine showing a conventional example.

[Explanation of symbols]

 1 Oil Separator 3 Cam Shaft 8 Blow-by Gas Passage 9 Sealing Mechanism 10 Inlet 11 Partition 14 Oil Outlet 15 Oil Outlet 16 Communication Port 17 Chain Chamber 18 Valve Room 21 Outlet 31 Oil Separator 33 Idler Gear 45 Partition 46 Perimeter End portion 47 Cylindrical portion 50 Intake disc 51 First separation chamber 52 Second separation chamber 60 Outlet disc

Claims (4)

[Claims] Claim: What is claimed is: 1. An intake disc and an outlet disc are coupled to a rotary shaft to which a rotational force of an engine is transmitted, and a partition wall defining a first separation chamber and a second separation chamber is provided between the intake disc and the outlet disc. An oil discharge port is opened in the outer periphery of the first separation chamber and the second separation chamber, an intake port for introducing blow-by gas into the second separation chamber is opened in the intake disc, and a second blow-by gas from the first separation chamber is opened in the partition wall. A communication port for introducing into the separation chamber is opened, an outlet for introducing blow-by gas from the second separation chamber into the intake pipe of the engine is opened for the outlet disk, and the communication port is rotated in the radial direction with respect to the inlet and the outlet. Alternatively, the blow-by gas oil separator is arranged offset in the circumferential direction of rotation. 2. The blow-by gas oil separator according to claim 1, wherein the total opening area of the communication port is smaller than the total opening area of the inlet. 3. The blow-by gas oil separator according to claim 1, wherein a cylindrical portion defining a communication port is projected from the partition wall into the first separation chamber. 4. The blow-by according to any one of claims 1 to 3, wherein the outer peripheral end of the partition wall is folded back toward the outlet disk so as to cover the oil discharge port communicating with the second separation chamber. Gas oil separator.