Gear pump having a bearing with a temperature adjusting medium passage

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a gear pump for carrying high viscous fluid such as molten resins.

2. Description of the Related Art

For example, the gear pump for carrying molten resins has a pair of gear rotors, that being supported rotatably the pump body through a bearing. The bearing is a slide bearing, which is of a self-lubricating type in which a part of the molten resins to be carried as bearing lubricating agent.

In the gear pump of this kind, it is important to increase the production amount (carrying amount), and methods thereof include a method for increasing the number of revolutions and a method for widening the tooth width. However, in any of these methods, the burden on the bearing increases to lead to high possibility of baking, which makes difficult to increase the production amount.

That is, when the number of revolutions is increased, the shearing speed is high, which results in high heat generation of resins and lowering bearing support ability. Further, when the tooth width is widened, the load increases, and the bearing support ability lowers.

In view of the above, in the gear pump of this kind, it is most effective for enhancing the bearing ability to lower a temperature of the molten resins as lubricant to raise the viscosity of resins.

Methods for cooling the lubricant (molten resins) include a method for cooling a rotor shaft (for example, see U.S. Pat. No. 5,292,237), a method for cooling a bearing (for example, see U.S. Pat. No. 5,924,854), or a method for cooling a bearing (for example, see Japanese Patent Application Laid-Open No. Hei 10-141247 Publication).

In the aforementioned U.S. Pat. No. 5,924,854, a bearing and a viscous seal are integrated to thereby prevent leakage of a temperature adjusting medium and that of resins.

However, this poses a problem that because of the construction in which the bearing is secured to the body, an unreasonable load is applied to the bearing.

That is, since the bearing is pressed in a different direction depending on the operating conditions such as the discharge pressure or the number of revolutions, it is preferable that the bearing be mounted in the free state with respect to the body. However, when it is secured to the body as in the prior art described previously, there occurs a problem that the unreasonable load is applied to the bearing.

Especially, in case of an arrangement in which a bearing is cooled, a clearance present between the bearing and the body is further enlarged by cooling the bearing, which makes the problem further serious.

The aforementioned integral type has a problem that manufacturing is difficult and the cost increases.

On the other hand, in the disclosure of Japanese Patent Application Laid-Open No. Hei 10-141247 Publication, the bearing is constituted separately from the viscous seal, but there is a problem that the cooling medium leaks or assembling is difficult.

That is, an inlet passage or an outlet passage of cooling medium with respect to the bearing are provided on a cover (side plate) for securing the bearing, and a seal construction between the cover and the bearing is difficult.

It is therefore an object of the present invention to provide a gear pump for carrying high viscous liquid, which keeps a bearing free, and enhances reliability relative to leakage of cooling medium or leakage of molten resins.

SUMMARY OF THE INVENTION

For achieving the aforementioned object, the present invention employs the following constitutions.

According to the present invention, there is provided a gear pump comprising: a body; a bearing; a pair of gear rotors, said gear rotors being supported on said body through said bearing; a cover for preventing said bearing from being slipped out in the axial direction of said bearing, said cover being secured to said body; a temperature adjusting medium passage formed in said bearing; an inlet pipe provided on the axial outer end of said bearing, said inlet pipe being communicated with said temperature adjusting medium passage; an outlet pipe provided on the axial outer end of said bearing, said outlet pipe being communicated with said temperature adjusting medium passage; and an intermediate plate interposed between the axial outer end of said bearing and said cover, said intermediate plate being formed with a hole for inserting said input pipe and said outlet pipe therein, wherein said cover is provided with a guide portion having said inlet pipe and said outlet pipe loosely fitted therein to guide them to outside.

The provision of the intermediate plate, as described above, enables positive prevention of the leakage of temperature adjusting medium and the leakage of material to be carried. In addition, in place of inserting the inlet pipe and the outlet pipe into the cover, constitution of inserting them into the intermediate plate may be employed to thereby facilitate assembling.

In the gear pump according to the present invention, preferably, said bearing is held on said body in a non-secured state. By such a constitution as described, unreasonable load is not applied to the bearing.

In the gear pump according to the present invention, preferably, the pump is for carrying molten resins.

In the gear pump according to the present invention, preferably, constitution is employed in which a part of the carried material to be supplied as lubricant between said bearing and said gear rotor.

In the gear pump according to the present invention, constitution is employed in which said guide portion is depressed along the diametrical direction of said rotor on the intermediate plate side end of said cover.

In the gear pump according to the present invention, both end surfaces of said intermediate plate may comprise seal surfaces.

In the gear pump according to the present invention, both end surfaces of said intermediate plate may contact with said bearing and said cover through a seal member.

In the gear pump according to the present invention, said inlet pipe and said outlet pipe may be mounted on said bearing through watertight means.

In the gear pump according to the present invention, said intermediate plate may be integrated with a thrust plate provided in order to locate said bearing in an axial direction. Said thrust plate is provided separately from said bearing.

Further, in the gear pump according to the present invention, there are provided a viscous seal for preventing leakage of liquid form said gear rotor, said viscous seal being provided at an axial outer position of said bearing, and fastening means provided on said viscous seal, said fastening means raising mounting surface pressure of said intermediate plate and said cover.

Further, according to the present invention, there is provided a gear pump comprising: a body; a bearing; a pair of gear rotors, said gear rotors being supported on said body through said bearing; a cover for preventing said bearing from being slipped out in the axial direction of the bearing, said cover being secured to said body; temperature adjusting medium passage formed in said bearing; an inlet pipe provided on the axial outer end of said bearing, said inlet pipe being communicated with said temperature adjusting medium passage, at least a part of said inlet pipe being formed from a flexible member; and an outlet pipe provided on the axial outer end of said bearing, said outlet pipe being communicated with said temperature adjusting medium passage, at least a part of said outlet pipe being formed from a flexible member, wherein said cover is provided with a guide portion having said inlet pipe and said outlet pipe loosely fitted therein to guide them to outside.

By being constituted as described above, it is possible to realize a gear pump capable of preventing leakage of temperature adjusting medium and leakage of material to be carried positively, and facilitating assembling.

Further, in the gear pump according to the present invention, constitution can be employed in which the guide portion is provided in parallel with the shaft center of the gear rotor, and the diameter of the guide portion is larger than that of the inlet pipe and larger than that of the outlet pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a sectional view of a gear pump showing an embodiment of the present invention, which is a sectional view taken on line I—I of

FIG. 2

;

FIG. 2

is a side view taken from

FIG. 1

;

FIG. 3

is a circumferential developed view of a temperature adjusting medium passage;

FIG. 4

is an enlarged sectional view of a main part of an embodiment of the present invention;

FIG. 5

is a view taken on arrow A of

FIG. 4

;

FIG. 6

is an enlarged sectional view of a main part showing a further embodiment of the present invention;

FIG. 7

is an enlarged sectional view of a main part showing another embodiment of the present invention;

FIG. 8

is an enlarged sectional view of a main part showing still another embodiment of the present invention;

FIG. 9

is a sectional view of a gear pump showing a further embodiment of the present invention;

FIG. 10

is an enlarged sectional view of the main part of

FIG. 9

;

FIG. 11

is an enlarged sectional view showing a seal construction of an inlet pipe or an outlet pipe and a guide portion of a viscous seal; and

FIG. 12

is an enlarged sectional view showing a further seal construction of an inlet pipe or an outlet pipe and a guide portion of a viscous seal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention will be described hereinafter with reference to the drawings.

Shown in

FIGS. 1 and 2

is a gear pump for carrying quantitative molten resins in a mixing granulating system. The gear pump has a pump body

1

, and a pair of gear rotors

2

encased in the body

1

.

The body is formed into a block form, within which a glasses-like rotor housing hole

3

is formed, and a resin inlet

4

and an outlet

5

are formed in an axial central portion of the rotor housing hole

3

and on both sides in a diametrical direction. The pair of gear rotors

2

,

2

are rotatably housed in the rotor housing hole

3

through a bearing

6

.

The rotor

2

comprises a gear part

7

and shaft parts

8

formed on both sides of the gear part

7

. The gear part

7

of the pair of rotors

2

,

2

is always meshed, and the shaft part

8

is supported on the bearing

6

.

One end of the shaft part

8

of the rotor

2

is connected to a drive device (not shown) through a coupling

9

, the rotor

2

being rotated and driven in a direction of arrow a, and molten resins are carried from the resin inlet

4

to the outlet

5

by the gear part

7

.

The bearing

6

is fitted in the rotor housing hole

3

in a non-secured state. The bearing

6

is formed cylindrically, an inner circumferential surface thereof being a slide bearing surface, and a part of an outer circumferential surface being cut and formed to be a flat surface. The bearing

6

is housed in the glasses-like rotor housing hole

3

, in which state the flat surfaces come in contact with each other to prevent rotation thereof. It is noted that the outside diameter of the bearing

6

is about 600 mm in case of a large one.

The axial inner end of the bearing

6

can be placed in contact with the side of the gear part

7

of the rotor

2

. The axial outer end of the bearing

6

is substantially flush with the end of the body

1

.

The bearing

6

is prevented from being slipped out outward in an axial direction by a cover

11

mounted on the end of the body through an intermediate plate

10

. And, a small diameter shoulder is formed on the outer circumferential portion of the axial outer end of the bearing

6

, and a ring-like thrust plate

12

is fitted in the shoulder.

It is noted that the thrust plate

12

may be integrated with the bearing

6

.

The intermediate plate

10

is formed from a single plate, which has a pair of through-holes

13

for loosely fitting the shaft part

8

of the gear rotor

2

. The outer shape of the intermediate plate

10

has size for covering the whole end of the bearing

6

and a part of the end of the body

1

, and the thickness of the intermediate plate

10

is about 60 mm.

The cover

11

is a weight member formed from a block, whose outer shape is substantially the same as the intermediate plate

10

, and whose thickness is about 200 mm. The cover

11

is secured to the end of the body

1

through a bolt

14

.

The cover

11

is provided with a pair of seal member insert holes

15

which are concentric with the shaft center of the gear rotor

2

, and a viscous seal

16

is fitted in the hole

15

.

The viscous seal

16

is formed into a cylindrical body with a flange, whose outer circumferential surface is partly formed with a flat surface, and a pair of viscous seals

16

have flat surfaces placed in contact with each other, similar to the bearing

6

. The flange of the viscous seal

16

is secured to the cover

11

through a bolt

17

. The axial inner end of the viscous seal

16

faces to the outer end of the intermediate plate

10

. The inner circumferential surface of the viscous seal

16

and the shaft part

8

of the gear rotor

2

prevent the molten resin from flowing out by means of a labyrinth seal.

A rotor temperature adjusting device

18

is provided on the shaft center portion of the rotor

2

, and a control device (not shown) for supplying temperature adjusting medium is connected to the adjusting device

18

. Since their details are the same as those described in U.S. Pat. No. 5,292,237, reference is made thereto, and the detailed explanation thereof is omitted.

The bearing

6

is also provided with a bearing temperature adjusting device

19

, and a control device (not shown) for supplying a temperature adjusting medium is connected to the adjusting device

19

. The bearing temperature adjusting device

19

has a temperature adjusting medium passage

20

formed internally of the bearing

6

. The temperature adjusting medium passage

20

comprises an annular space

21

formed internally of the bearing

6

, and a partitioning wall

22

provided in the annular space

21

.

FIG. 3

is a circumferential developed view of the temperature adjusting medium passage

20

, and the partitioning wall

22

is provided spirally. The annular space

21

is formed with the temperature adjusting medium passage

20

comprising two spiral grooves, and a temperature adjusting medium inlet

23

is formed in the end of one of the grooves, and a temperature adjusting medium outlet

24

is formed in the end of the other.

As shown in

FIG. 4

, the bearing

6

is constituted by an inner circumferential member

6

a

and an outer circumferential member

6

b

connected integrally, and the temperature adjusting medium passage

20

is formed in a boundary of the inner circumferential member

6

a

and the outer circumferential member

6

b.

In this embodiment, an annular recess for forming the annular space

21

is formed in the outer circumferential surface of the inner circumferential member

6

a

, and the spiral partitioning wall

22

shown in

FIG. 3

is formed integrally within the annular recess. And, the outer circumferential member

6

b

is fitted in the inner circumferential member

6

a

to form an integral configuration. This integral configuration is done welding or welding after shrinkage fitting.

In the integrated state as described, the outer circumferential surface of the partitioning wall

22

is in contact with the inner circumferential surface of the outer circumferential member

6

b.

The partitioning wall

22

is formed over the inner and outer circumferential surfaces of the annular space

21

as described above whereby the partitioning wall

22

functions as a strengthening member. Accordingly, even if the annular space

21

is made larger in order to raise the cooling effect, the lowering of the bearing strength can be strengthened.

In the present invention, alternatively, the annular recess may be provided in the inner circumferential surface of the outer circumferential member

6

b

to provide the partitioning wall

22

. Further, the temperature adjusting medium passage

20

may not be limited to the double spiral groove construction, but a groove construction by way of a combination of a circumferential partitioning wall and an axial partitioning wall may be employed. Furthermore, a conventional snaking hole described in U.S. Pat. No. 5,924,854 may be employed.

The temperature adjusting medium inlet

23

and outlet

24

are constituted by a diametrical hole

25

bored from the outer circumferential surface of the bearing

6

toward the annular space

21

, and an axial hole

26

bored from the outer end surface of the bearing

6

toward the diametrical hole. The outer end of the diametrical hole

25

is sealed by a plug

27

.

An inlet pipe

28

and an outlet pipe

29

are connected to the axial outer end of the bearing

6

. Ends of the inlet pipe

28

and the outlet pipe

29

are connected to the axial hole

26

through water-tight means

30

so as to eliminate liquid leakage.

In the present embodiment, as the water-tight means

30

, welding is employed, but it is not limited to welding. The liquid leakage may be prevented by screwing, and adhesive or sealing agent.

The thrust plate

12

and the intermediate plate

10

are provided with insert holes

31

in the form of extending-through concentric with the axial hole

26

. The inlet pipe

28

or the outlet pipe

29

is inserted into the insert hole

31

in a loosely fitted manner.

As shown in

FIG. 5

, the cover

11

is provided with a guide portion

32

for loosely fitting and guiding the inlet pipe

28

and the outlet pipe

29

to outside. The guide portion

32

is constituted by U-shaped recess that is recessed in the diametrical direction of the rotor on the intermediate plate side end of the cover

11

.

At least a part of the inlet pipe

28

and the outlet pipe

29

is formed from a flexible tube to be bendable. Accordingly, the inlet pipe

28

and the outlet pipe

29

extending axially-outwardly from the end of the bearing

6

may be bended at right angle immediately after moving out of the insert hole

31

of the intermediate plate

10

and extended diametrically-outwardly along the guide portion

32

of the cover

11

.

The inlet pipe

28

and the outlet pipe

29

projected diametrically-outwardly from the outer circumferential surface of the cover

11

are connected to a control device not shown. The temperature adjusting medium supplied to the inlet pipe

28

from the control device (not shown) flows into the spiral groove-like temperature adjusting medium passage

20

from the inlet

23

to adjust the temperature of the bearing

6

, after which the medium passes from the outlet

24

to the outlet pipe

29

, and then returns to the control device (not shown).

Temperature detecting means for detecting temperature of the bearing temperature adjusting medium is provide so as to detect outlet temperature of the temperature adjusting medium within the bearing

6

. By the temperature detecting means, the temperature of the bearing temperature adjusting medium is controlled by the control device. Although not shown, the rotor temperature adjusting device

18

is also provide with temperature detecting means.

The gear pump is of the self-lubricating type in which a part of the molten resin to be carried is supplied as lubricating agent for the bearing

6

and the shaft part

8

. As the self-lubricating construction, a well-known construction (for example, those described in publications listed with respect to prior art) may be employed, details of which are therefore omitted. The viscous seal

16

is to prevent leakage of molten resins to outside used in lubricating the bearing.

As shown in

FIG. 4

, the molten resin is supplied to a first clearance

34

between the outer circumferential surface of the shaft part

8

of the rotor

2

and the inner circumferential surface of the bearing

6

and used to lubricate the bearing, and also moves into a second clearance

35

between the outer circumferential surface of the bearing

6

and the inner circumferential surface of the rotor housing hole

3

of the body

1

.

The molten resin in the first clearance

34

is prevented from leaking to outside from the shaft part

8

by the viscous seal

16

, and is prevented from leaking to the insert hole

31

of the intermediate plate

10

and to the guide portion

32

of the cover

11

by the face contact between the intermediate plate

10

and the outer end of the bearing

6

and the face contact between the intermediate plate

10

and the inner end of the cover

11

.

The resin in a portion indicated by numeral

33

is sealed by the outer end of the intermediate plate

10

and the inner end of the cover

11

, and the resin in that portion is of the construction of returning to the suction side.

Further, the molten resin in the second clearance is prevented from leaking to the insert hole

31

of the intermediate plate

10

by the face contact between the inner end of the intermediate plate

10

and the outer end of the bearing

6

(in this embodiment, the end of the thrust plate

12

).

That is, both ends of the intermediate plate

10

are constituted on the seal surface for preventing leakage of molten resin. That is, both ends of the intermediate plate

10

constitute a seal portion.

The operation of the gear pump for carrying molten resins constructed as described above will be explained hereinafter.

At the start of the gear pump, the heated medium is supplied from the control device (not shown) to the rotor temperature adjusting device

18

and the bearing temperature adjusting device

19

to preheat the rotor

2

and the bearing

6

thus preventing lubricating molten resins from cooling and solidifying. When preheating is finished and carrying molten resins is started, the temperature of the heated medium is lowered to switch to the cooling medium to cool the rotor

2

and the bearing

6

, thus suppressing heat generation of the lubricating molten resins, suppressing lowering of viscosity under the high temperature to prevent the bearing support ability from lowering.

Alternatively, a cooling medium supply source and a heated medium supply source are individually provided, and supplied medium switching valve can be used to switch media. In this case, as the cooling medium out of the temperature adjusting media, oil, water, air or the like is used, and as the heated medium, oil can be mainly used. As other heated media, water, vapor or the like can be used.

Further, with respect to the control devices for the rotor temperature adjusting device and the bearing temperature adjusting device, a single device can be used in a combined manner. And the rotor temperature and the bearing temperature are controlled individually with the single device.

The leakage of these temperature adjusting media is prevented with high reliability since the bearing

6

, and the inlet pipe

28

and the outlet pipe

29

are connected through the water-tight means

30

.

Further, the leakage of the molten resins is prevented securely since the intermediate plate

10

is provided to make both ends thereof to serve as seal surface. In this case, unless the intermediate plate

10

is provided, it is difficult to prevent leakage from the second clearance

35

to the U-shaped guide portion

32

of the cover

11

.

The provision of the intermediate plate

10

results in effect, in addition to raising the seal effect of molten resins, of facilitating assembling. That is, since the cover

11

is a weight member, it is very difficult to mount the cover on the end of the body

1

while inserting the inlet pipe

28

and the outlet pipe

29

projected from the end of the bearing

6

. However, the intermediate plate

10

is provided whereby it is possible to employ the constitution in which the inlet pipe

28

and the outlet pipe

29

need not be inserted (the U-shaped guide portion

32

), to facilitate assembling.

FIG. 6

shows another embodiment of the present invention, which is different from the embodiment described previously in that both ends themselves of the intermediate plate

10

are not made to serve as seal surfaces but the seal member is provided.

That is, O-ring fitting grooves are provided in the peripheral edges of the inlet pipe insert hole

31

and the outlet pipe insert hole

31

of the end on the bearing side of the intermediate plate

10

, and a first O-ring

36

is fitted in the groove. Further, in the end on the cover side of the intermediate plate

10

, an O-ring fitting groove concentric with the shaft center of the rotor is provided on the inner circumferential side with respect to the shaft center of the rotor of the insert hole

31

, and a second O-ring

37

as a seal member is fitted in the groove.

Alternatively, one surface of the intermediate plate

10

is made to have a seal member

36

or a seal member

37

interposed, and one surface itself on the opposite side is made to serve as seal surface. Further, alternatively, a recess is provided on the intermediate plate side of the thrust plate

12

to fit the first O-ring

36

therein, and recess is provided on the intermediate plate side of the cover

11

to mount the second O-ring

37

thereon.

In the present invention, preferably, fastening means

40

(see

FIG. 1

) for pulling the bearing

6

in the direction of the cover

11

and holding the intermediate plate

10

with the great force so as to raise face pressure is provided on the viscous seal

16

in order to raise the seal effect of the intermediate plate

10

. As the fastening means

40

, preferably, separately from the arrangement that the viscous seal mounting bolt

17

is screwed into the cover

11

, it is screwed into the bearing

6

(in the illustration, the thrust plate

12

) extending through the cover

11

and the intermediate plate

10

. By doing so, L/D (length to diameter) of the bolt

40

can be made sufficiently large, and the movement of the bearing can be secured with flexure of the bolt

40

.

Alternatively, the bolt

17

may be screwed into the intermediate plate

10

extending through the cover

11

so as to increase face pressure on the outer end side of the intermediate plate

10

. With the constitution as described, the movement of the bearing can be made more free as compared with the configuration of being screwed into the bearing

6

.

Preferably, the direction of piping of the inlet pipe

28

or the outlet pipe

29

is made to be obliquely downward instead of horizontal direction. Piping is done obliquely downward as described above whereby even if leakage of resin should occur, the resin is not returned into the gear pump along the piping but is discharged outside.

Preferably, Ag plating is applied to the inner circumferential surface of the bearing

6

. By applying plating as described, even if the peripheral speed of the rotor shaft part

8

is 0.5 m/s or more, the long service life of 10˜20 years can be achieved together with the cooling construction of the bearing

6

.

FIG. 7

shows still another embodiment of the present invention, in which a part of the inlet pipe

28

or the outlet pipe

29

is not to be a flexible tube, but an elbow

38

is used to provide a rigid pipe bended at right angle. Other constitutions are the same as those described previously.

FIG. 8

shows another embodiment of the present invention, in which the thrust plate

12

is constituted separately from the bearing

6

, and the intermediate plate

10

of the present invention is replaced by the thrust plate

12

.

In this embodiment, the inlet pipe

28

and the outlet pipe

29

are extended in an axial direction, and the guide portion

32

for loosely inserting the inlet pipe

28

and the outlet pipe

29

into the cover

11

and the flange of the viscous seal

16

is provided in parallel with the shaft center of the rotor

2

. The guide portion

32

is formed to be considerably larger than the inlet pipe

28

and the outlet pipe

29

to facilitate mounting of the cover

11

. A bite pipe joint

39

is provided between the end of the guide portion

32

of the viscous seal

16

and the inlet pipe

28

and the outlet pipe

29

to prevent leakage of liquid.

FIG. 9

shows still another embodiment of the present invention, in which shows a gear pump of the type having no intermediate plate

10

. Members common to those described in the respective embodiments described previously are designated by the same reference numerals, description of which is omitted.

FIG. 10

shows the main part of FIG.

9

. As shown, the guide portion

32

parallel with the axial direction is formed extending through the cover

1

and the flange of the viscous seal

16

. The hole of the guide portion

32

is provided concentric with the axial hole

26

, and is formed to be larger than the outside diameter of the inlet pipe

28

or the outlet pipe

29

. In the inlet pipe

28

and the outlet pipe

29

, a portion located at the guide portion

32

of the cover

11

is formed from a flexible tube.

The guide portion

32

is made larger in diameter, and a part of the pipe is made flexible whereby when the cover

11

is mounted, the inlet pipe

28

and the outlet pipe

29

are centered to the guide portion

32

to facilitate the insertion.

Between the outer end of the bearing

6

and the inner end of the cover

11

, the first O-ring

36

as seal means is provided on the peripheral edge of the guide portion

32

.

Leakage of molten resins in the first clearance

34

and the second clearance

35

to the guide portion

32

is prevented by the first O-ring

36

as the seal means.

FIG. 11

shows the details of a seal construction between the inlet pipe

28

and the outlet pipe

29

, and the end of the guide portion

32

of the viscous seal

16

, both of which are sealed by a bite pipe joint

39

.

In

FIG. 12

, an O-ring

41

is used in place of the bite pipe joint to carry out sealing.

Preferably, Ag plating is applied to the inner circumferential surface of the bearing

6

. By applying plating as described, even if the peripheral speed of the rotor shaft part

8

is 0.5 m/s or more, the long service life of 10˜20 years can be achieved together with the cooling construction of the bearing

6

.

The present invention is not limited to those shown in the aforementioned embodiments, but for example, the invention is not limited to one for carrying molten resins, and further, the guiding direction of the inlet pipe or the outlet pipe is not particularly limited. Further, as the temperature adjusting media, only the cooling medium will suffice.