JP3445950B2 - Transformer box side plate and press mold equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side plate of a transformer box.
And a press molding die device for this side plate.

[0002]

2. Description of the Related Art An insulating oil is filled in a container box of a transformer that houses electric equipment such as an iron core and a coil in order to cool heat generated by the electric equipment during operation. In order to enhance the heat dissipation effect, a large number of fin structure heat dissipation plates are provided on the side plate of the container box so as to maximize the contact area with the outside air.

Regarding this side plate, Japanese Patent Publication No. 62-418.
It is disclosed as a product molded by this apparatus in the "press molding die apparatus" of Japanese Patent No. 10, and the side plate is assembled to form a container.

That is, the side plate is made of a plate-shaped steel plate material .
Bending the steel plate material into a substantially U shape to form a space inside
A large number of the heat radiating plate portions are provided in parallel, and both end portions of each heat radiating plate portion are crushed into a narrowed portion.

Therefore, the insulating oil filled in the container and heated by the heat generated by the electric device enters into the inner spaces of the large number of fins of the fin structure and is cooled, thereby suppressing internal overheating. In this respect, the above invention was extremely effective.

[0006]

However, in the above configuration,
Insulating oil stayed in the container and was not sufficiently circulated to the internal space of the heat dissipation plate, resulting in dissatisfaction with insufficient cooling effect.

From the viewpoint of product cost, it is desirable that the container be as small as possible and the amount of insulating oil to be filled be the minimum. On the other hand, if the container is small and the amount of insulating oil is small, it will overheat. There is an easy problem.

The present invention was developed in order to solve the above-mentioned conventional problems and dissatisfactions. The side plate is provided so that the insulating oil filled in the container can circulate sufficiently to achieve efficient cooling. It is an object of the present invention to construct and to make it possible to press-mold this side plate very easily.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a transformer container obtained by press-molding a flat steel plate material.
The side plate of the box, which is made of the above steel plate material and bent into a substantially U shape.
A large number of heat sinks that are bent to form spaces inside are arranged in parallel.
Provided , crushing both ends of each heat radiating plate portion to form a first throttle part, and forming a base end portion along the length direction of the heat radiating plate portion at both end portions for communicating with a space. It is characterized in that the second narrowed portion is formed by crushing in a form.

Therefore, the insulating oil heated in the container box causes convection inside due to the heat, passes through the internal space from the through holes in the upper part of each radiator plate, and returns to the center of the container box from the through holes in the lower part. The circulation is repeated, and a certain degree of cooling is performed when passing through the internal space of each heat radiating plate portion, so that the cooling of the insulating oil is achieved as a whole.

In this case, if the inside of the first throttle portion closing both sides of the heat radiating plate portion is inclined toward the inner side in the projecting direction of the heat radiating plate portion, the insulating oil that has penetrated from the through hole in the upper part Would be able to smoothly flow into the interior space and circulate.

Next, the mold device for press-molding the side plate of the transformer box is a flat plate-shaped core metal having a cutout window opened in the lower portion along the length direction and fixed upright in the center of the bed. A die, a pair of cam drivers arranged to face each other along the longitudinal side centering on the core die and having an inclined cam surface descending toward the core die, and supporting a flat steel plate material from below. Guided by the inclined cam surface of the cam driver, slides down and comes into contact with a pair of material support plates that are in close proximity to the upper surface of the steel plate material, sandwiches the material support plate from above and below, and descends while being guided by the inclined cam surface of the cam driver. A pair of upper molds that are in close proximity to each other, and a deep groove having a length substantially equal to the length of the core mold is formed on at least one opposing surface of the pair of upper molds, and a shallow groove is formed on both sides of the deep groove. Install the formed mold plate In addition, in the lower surface of the deep groove, in the approaching posture of the pair of upper molds, a protruding strip that fits into the cutout window of the core mold together with a part of the steel plate material is projected along the length direction. .

Therefore, when the pair of material support plates holding the steel plate material from above and below and the pair of upper molds are guided by the inclined cam surfaces of the cam driver and slid down, the steel plate material is placed on the upper end of the core mold. It abuts and is forced to be bent by further descending.

Further, since the pair of upper molds also slide in the direction in which they approach each other by the inclined cam surfaces of the cam driver simultaneously with this descending operation, the steel plate material is pressed against both surfaces of the core mold, In addition, both ends are narrowed down and crimped by the molding die plate formed by the deep groove and the shallow groove provided on the facing surface of the upper die, and the projection at the base end is fitted into the notch window of the core die. It becomes the form to be narrowed down and crimped.

In this manner, the flat plate-shaped steel plate material is bent at a right angle and is also inverted and bent, and a space corresponding to the thickness of the core die is formed to form a heat dissipation plate portion, which is composed of a deep groove and a shallow groove. The formed die plate crushes both ends of the heat dissipation plate to form the first narrowed part, and the protrusions are fitted into the cutout windows of the core mold. The second narrowed portion is formed by crushing the base end portion along the direction in the form of through holes at both end portions.

In this case, if the both ends of the square plate-shaped core die are cut off obliquely, the first throttle portion is formed inside the heat dissipation plate portion when the first throttle portion is formed. It can be configured to be inclined toward.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, FIG. 1 shows a container box 1 of a transformer according to the present invention, in which electric equipment such as an iron core and a coil is housed and filled with a cooling insulating oil ( In order to enhance the heat radiation effect, a large number of fin-shaped heat radiation plate portions 3 are provided on the side plate 2 of the container box 1 so as to maximize the contact area with the outside air.

The side plate 2 is made of a flat plate steel material 2 ' ,
Steel plate material 2'is bent into a substantially U-shape and has a space inside
A large number of heat radiating plate portions 3 having 3'is provided in parallel, and both ends of each heat radiating plate portion 3 are crushed to form the first narrowed portion 4, and the heat radiating plate portions 3 are arranged along the length direction. The base end portion is crushed in a form in which the through holes 5 communicating with the space 3 ′ are formed at both end portions to form the second narrowed portion 6 (see FIGS. 2 and 3).

The first narrowed portion 4 is surface-bonded by crushing both ends of the steel sheet material 2'member which is inverted and bent into a substantially U-shape, and both ends are welded to form a shield 7 portion to form insulating oil. Is designed not to leak, and the first throttle part 4
The inner side of the is a slanted portion 4 ′ that is directed inward in the protruding direction of the heat dissipation plate 3.

Therefore, when the side plate 2 is assembled as a part of the container box 1 with the longitudinal sides of the heat radiating plate portions 3 in the vertical posture and is used as a transformer, the insulating oil heated inside will pass through the upper part of the insulating oil. It intrudes through the hole 5 and is guided by the upper inclined portion 4 ′ to flow into the space 3 ′, is cooled to some extent in this space 3 ′ of the heat dissipation plate portion 3, and is further guided to the lower inclined portion 4 ′. The circulation is performed from the lower through hole 5 back into the container box 1 to prevent the transformer from overheating during operation (see FIG. 3).

Next, FIG. 4 and subsequent figures show a press-molding die device for the above-mentioned side plate 2. First, in the center of the bed 10 of the crank press molding machine, a square plate-shaped core die 11 is formed.
Is fixed upright. The core mold 11 has a configuration in which both ends are cut off obliquely to provide a cutout portion 12, and a cutout window 13 is opened in the lower portion along the length direction. The length, height, and wall thickness of the core die 11 are determined according to the length, the protruding height, and the width of the space of the heat dissipation plate portion 3 of the side plate 2 to be molded.

The core mold 11 is fitted on the bed 10 between a pair of sandwiching plates 14 which are vertically erected and fixed at a predetermined interval corresponding to the thickness of the core mold 11, and via a fixture 15. It will be fixed detachably. Therefore, core mold 1
A large number of 1 are prepared according to the size and form of the side plate 2 and the heat radiating plate portion 3, and are appropriately replaced depending on the situation.

On the bed 10, the core mold 11 described above is provided.
A pair of cam drivers 16 are erected and fixed so as to be opposed to the longitudinal surface of the cam driver 16, and the surfaces of the cam drivers 16 that are opposed to each other descend in the direction of the core mold 11 at an angle of 45 degrees. The cam surface 17 is inclined.

In the illustrated embodiment, the cam driver 16 is in the form of a right-angled triangle having a cam surface 17 as a hypotenuse, and is arranged so as to face each other with three core molds 11 interposed therebetween.
However, the central cam driver 16a can be fixed at a predetermined position by moving it laterally (direction of arrow A) according to the width size of the side plate 2.

Further, on the bed 10, a thick plate elevating plate 18 is mounted by being supported from below by an air cushion rod 19 protruding from the bed 10, and the elevating movement of the rod 19 maintains a horizontal posture. Move up and down (direction of arrow B).

In this case, the core mold 1 of the lifting plate 18
Since the window hole 18a is opened in the portion corresponding to 1 and the portion corresponding to the cam driver 16 is cut out,
There is no hindrance to the lifting movement of the lifting plate 18.

Then, on the upper surface of the elevating plate 18,
A pair of material support plates 20 facing each other across the longitudinal surface of the core mold 11 protruding from the window hole 18a are placed, and the pair of material support plates 20 are mutually connected by air cylinders 21 at both ends thereof. Are linked to.

Further, a part of the lower surface of each of the pair of material support plates 20 is an inclined surface 20a having an angle of 45 degrees which is in contact with the cam surface 17 of the cam driver 16, and the air cylinder 21 is free. When the raising / lowering plate 18 is lowered, the pair of material support plates 20 merely placed on the raising / lowering plate 18 also lowers, but at the same time, they are guided by the cam surface 17 and come close to each other. The opposing surfaces of the material support plate 20 are in surface contact with the lower portion of the core mold 11 located therebetween (see, for example, FIG. 8).

The air cylinder 21 is used for the lift plate 1.
When the pair of material support plates 20 are raised by raising 8 and the pair of material support plates 20 are raised, they are operated so as to separate them from each other (direction of arrow C).

Next, the ram 22 of the crank press molding machine
On the lower surface (not shown in FIG. 4), a pair of upper molds 23 are connected to each other by an air cylinder 24 and assembled so as to be able to approach and separate from each other. That is, a part of the lower surface of each of the upper molds 23 is an inclined surface 23a having an angle of 45 degrees which comes into contact with the cam surface 17 of the cam driver 16 described above, and thus the ram 22 is freed with the air cylinder 24 free. And the upper die 23 also descends, and at the same time, they are guided by the cam surface 17 and approach each other.
Can be operated to separate from each other (direction of arrow D).

The facing surfaces 25 of the pair of upper molds 23 are in a so-called mold-closed state due to the above-mentioned downward approach, and are in contact with each other. The imaginary straight line formed by the facing surfaces in contact with each other is , Located directly above the longitudinal centerline of the core mold 11.

Of the pair of upper molds 23 described above, one upper mold 26 has a thick and wide mere block shape, and a part of the lower surface is cut as described above to form the inclined surface 23.
However, the upper mold 27 on the other side has a structure in which a plurality of guide blocks 27b (three in the illustrated embodiment) are continuously provided on the back surface of the square member 27a (the surface opposite to the facing surface 25 described above). The lower surface of the guide block 27b is cut off to form an inclined surface 23a.

Of the three guide blocks 27b, the central guide block 27c can be moved and fixed in the arrow E direction in correspondence with the above-described moving and fixing of the central cam driver 16a in the arrow A direction. , So that they face each other vertically.

Next, a cutout groove 28 is provided in the lower end portion of at least one of the facing surfaces 25 of the pair of upper molds 23, and in this cutout groove 28, the molding die surface of the heat dissipation plate portion 3 of the side plate 2 is formed. A molding die plate 29, which becomes the above, is detachably fitted via a fixture 30.

In the illustrated embodiment, the notch groove 28 and the mold plate 29 are provided on the respective facing surfaces 25, and each mold plate 29 here has a length substantially equal to the length of the core mold 11, A deep groove 29a having a depth width obtained by adding half the thickness of the core die 11 to the thickness of the steel plate material 2 ', and this deep groove 2
9a and a shallow groove 29b which is continuous with both sides of the steel plate material 2'and has a depth width corresponding to the thickness of the steel plate material 2 '. Further, a continuous portion of the shallow groove 29b and the deep groove 29a is formed in the cutout 12 of the core mold 11. Corresponding to the inclination, the inclined portion 29c is inclined upward toward the inside (see FIGS. 4, 9, 10 and the like).

Therefore, in the state where the pair of upper molds 23 are closed and one of the facing surfaces 25 is brought into surface contact with each other, the molding space formed by the pair of molding plate 29 is the core mold 1.
1, a pair of deep grooves 29a having a width substantially equal to the length of 1 and having a depth width obtained by adding the thickness of the core mold 11 to the thickness of two sheets of steel material 2 ', and two sheets of steel material 2' The pair of shallow grooves 29b having a depth width corresponding to the wall thickness is continuous with the pair of inclined portions 29c.

On the lower surface of the deep groove 29a of the one molding die plate 29, a protruding strip 31 is provided so as to project along the lengthwise direction corresponding to the cutout window 13 of the core die 11. The protrusions 31 are fitted into the cutout windows 13 of the core mold 11 when the pair of upper molds 23 are closed and the respective facing surfaces 25 are brought into surface contact with each other (see FIGS. 9, 10 and 11). ).

As described above, in the illustrated embodiment, the notch groove 28 and the molding die plate 29 are provided in the facing surfaces 25 of the pair of upper molds 23, but one facing surface 2
5 may be a flat surface, and the notch groove 28 or the molding die plate 29 having a predetermined depth may be provided only on the other facing surface 25. However, in this case, the standing position of the core mold 11 is not immediately below the face-to-face contact position of each facing surface 25 that is closed, but the other facing surface 2 is not.
It will be closer to 5.

Further, the protrusions 31 fitted into the cutout windows 13 of the core mold 11 are provided with the deep grooves 29 of one molding die plate 29.
The protrusion width is not limited to a, and it may be provided in a pair so as to face the deep groove 29a of the other molding die plate 29 as well, but in this case, each protrusion width is half. become.

Further, since the side plates 2 to be molded have various sizes, the molding plate 29 also has various sizes as the core mold 11 has various sizes as described above, and therefore the above-described molding plates 29 have various sizes. As described above, the mold plate 29 is detachable via the fixture 30.

In the press-molding die device having the above-described structure, the press-molding operation of the side plate 2 as a product is as follows.

First, the flat plate-shaped steel plate material 2'has a length and width required for the side plate 2 which is a product, and has a predetermined length and height according to the set width of the side plate 2. The core die 11 and the molding plate 29 having the above are selectively set, and the positions of the central cam driver 16a and the central guide block 27c are moved in the arrow A direction and the arrow E direction for adjustment and fixation. .

FIGS. 4 and 5 show the mold opening state in which the above-mentioned selective adjustment is performed. In this mold open state, the upper mold 23 is lifted by the rise of the ram 22, and both upper molds 23 are separated by the air cylinder 24, and a predetermined space is provided between the respective facing surfaces 25. The inclined surface 23a of the lower surface of the upper mold 23 is located above the cam surface 17 of the cam driver 16 and is opposed thereto.

On the other hand, when the air cushion rod 19 is in the ascending / advancing position, the ascending / descending plate 18 is moved up and down.
The pair of material supporting plates 20 mounted on the board 8 also rises, and the opposing surfaces of the pair of material supporting plates 20 are made equal to the above-described opening distance of the opposing surfaces 25 of the upper mold 23 by the operation of the air cylinder 21. Open to the extent.

Further, the inclined surface 20a formed on a part of the lower surface of the material support plate 20 is in contact with the cam surface 17 of the cam driver 16, and in this posture, the upper surface of the material support plate 20 has the upper surface of the core mold 11. It is at the same height level as the top edge (see Figure 5).

A locking groove 32 is formed in the lower surface of the square member 27a of the other upper die 27. Therefore, in FIG. 5, a steel plate material 2 ′ (omitted in FIG. 4) inserted and arranged between the upper die 23 and the material support plate 20 from the direction G (the direction from left to right in FIG. 5) viewed from the arrow. Is the material support plate 2
0 is mounted on the upper surface, and several heat dissipation plate portions 3 are already press-molded in part, and by shifting the heat dissipation plate portion 3 in the G direction by a predetermined pitch, the heat dissipation plate portion 3 immediately after molding is directly below the locking groove 32. To position.

In this state, when the ram 22 is lowered with a predetermined pressure (direction of arrow F), the upper die 23 is pushed down to sandwich the steel plate material 2 ′ against the upper surface of the material support plate 20. , The lower surface of the steel plate material 2'is the core mold 1
It contacts the upper end of 1 (see FIG. 6). Further, the heat radiating plate portion 3 immediately after molding has the above-described locking groove 32 of the upper die 23 that descends.
Insert and lock.

Then, the upper die 23 continues to descend due to the continuous pressing force applied to the ram 22, and the material support plate 20 pushed by the upper die 23 descends together with the elevating plate 18, so that the elevating plate 18 moves. The point of contact with the bed 10 is the descent limit. The lowering of the lifting plate 18 is due to the pressing force of the ram 22.
Since 8 is supported by the air cushion rod 19, it is buffered and is lowered gently.

The steel plate material 2'which is sandwiched between the upper die 23 and the material supporting plate 20 and descends is the core die 11
It is bent by further descending from the state of abutting on the upper end (see FIG. 7).

In this case, since the air cylinder 21 and the air cylinder 24 are in a free state, the inclined surfaces 20a of the pair of material support plates 20 are in contact with the cam surface 17 of the cam driver 16 at the same time as the above descent. Guided and slid, the respective facing surfaces approach each other in the descending limit and come into contact with the core mold 11. At the same time, the upper mold 23 slides while its inclined surface 23a is in contact with the cam surface 17 of the cam driver 16 so as to be guided and slides.
The molding die plates 29 of the respective facing surfaces 25 sandwich the bent steel plate material 2 ′ with the core die 11 as a core material (see FIGS. 8, 10, and 11).

That is, a part of the steel plate material 2 ′ is part of the upper die 23.
By descending, the core mold 11 is bent at a right angle with the core material and is inverted and bent into a substantially U-shape, and the core mold 11 is used as a spacer, that is, this core mold 11 part is used as a space 3 '.
The heat dissipation plate portion 3 is formed.

As described above, since the facing surfaces 25 of the pair of upper molds 23 approach each other at the same time and the pair of mold plates 29 are closed, the first and second molds 29 are closed. Second throttle portions 6 are respectively formed at the base end portions of the one throttle portion 4 and the heat dissipation plate portion 3 along the length direction.

The mold plate 29, as described above,
A deep groove 29a and a shallow groove 29b each having a predetermined depth width are provided with an inclined portion 29c.
Since the core metal mold 11 serves as a core material, the steel plate material 2 ′ is bent in a reverse direction and protrudes from both sides of the core metal mold 11 by closing the mold plate 29 having the core metal mold 11 as a core material.
The portion is molded while forming the inclined portion 4 ′ on the inner side as the first narrowed portion 4.

At the same time, the protruding strips 31 projecting from the deep grooves 29a of the one molding die plate 29 are fitted into the cutout windows 13 of the core die 11 together with a part of the steel plate material 2 '. In the portion, the steel sheet material 2 ′ portions facing each other are crushed and face-to-face with each other to form the second narrowed portion 6. Since the side end of the core mold 11 and the cutout window 13 are not crushed, the through hole 5 is left and formed in this portion.

In the series of operations described above, the upper die 23
Is not a vertical movement, but is a gradual form in which it is guided by the cam driver 16 and descends with an inclination of 45 degrees. The material support plate 20 that receives the pressing force of the upper mold 23 also passes through the air cushion rod 19. Since it is similarly inclined and lowered while being held by the lifting plate 18, all of the steel plate material 2 ′ is not subjected to excessive force during pressing,
The steel plate material 2'is bent very smoothly and is drawn.

[0056]

Therefore, the side of the transformer box according to the present invention
According to the plate , the heated insulating oil is circulated in the container to reliably cool the container. Therefore, the container can be downsized, and the insulating oil can be minimized while preventing overheating.

Further, according to the apparatus of the present invention, the first throttle portion, the inner inclined portion, the second throttle portion, and the single complete heat radiation plate portion having the through hole are formed into a series of Since press molding can be performed with one operation, and since it is a simultaneous process, there is no distortion or cracking on the side plate or deformation due to unreasonable force. It has many excellent effects such as being able to press-form with high accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view of a transformer box according to the present invention.

FIG. 2 is a partial cross-sectional perspective view of a side plate.

FIG. 3 is a cross-sectional view of only a heat dissipation plate portion of a side plate assembled as a container.

FIG. 4 is a perspective view of an apparatus according to the present invention.

FIG. 5 is a cross-sectional view of a mold open state.

FIG. 6 is a sectional view immediately before a pressing operation.

FIG. 7 is a cross-sectional view during a pressing operation.

FIG. 8 is a cross-sectional view when the pressing operation is completed.

FIG. 9 is a plan sectional view of the upper mold when the mold is opened.

FIG. 10 is a plan sectional view of the upper mold in a mold closed state.

FIG. 11 is an enlarged cross-sectional view of a main part when the pressing operation is completed.

[Explanation of reference numerals] 1; container box, 2; side plate, 2 '; steel plate material, 3; heat sink part,
3 '; space, 4; first throttle portion, 4'; inclined portion, 5; through hole, 6; second throttle portion, 7; shield, 10; bed,
11; core mold, 12; notch, 13; notch window, 14;
Holding plate, 15; Fixing device, 16; Cam driver, 16a;
Central cam driver, 17; cam surface, 18; lift plate, 18a; window hole, 19; air cushion rod, 2
0; material support plate, 20a; inclined surface, 21; air cylinder, 22; ram, 23; upper mold, 23a; inclined surface,
24; Air cylinder, 25; Opposing surface, 26; One upper mold, 27; Other upper mold, 27a; Square bar, 27b; Guide block, 27c; Central guide block, 28; Notch groove, 29; Mold Plate, 29a; Deep groove, 29b; Shallow groove, 29c; Inclined portion, 30; Fixing tool, 31; Protrusion, 3
2; locking groove.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A 52-143543 (JP, A) JP-A 61-42436 (JP, A) JP-A 59-125227 (JP, A) JP-A 61- 259839 (JP, A) Actual development Sho 58-118716 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B21D 53/02-53/08 B21D 13/02

Claims (4)

(57) [Claims] 1. A flat steel plate material (2 ') is press-formed.
The side plate of the transformer container box, which is the steel plate material (2 ′)
Is bent into a substantially U shape to form a space (3 ') inside
A large number of heat radiating plate portions (3) are provided in parallel, and both ends of each heat radiating plate portion (3) are crushed to form the first narrowed portion (4), and the length of the heat radiating plate portion (3) is also formed. A second end portion (6) is formed by crushing a base end portion along the direction in a form in which a through hole (5) communicating with the space (3 ′) is formed at both end portions. Side plate of transformer box. 2. The inner side of the first throttle portion (4) is inclined toward the inner side in the protruding direction of the heat dissipation plate portion (3).
The side plate of the transformer box described in. 3. A press molding die apparatus for a side plate (2) of a transformer box (1) according to claim 1 or 2, wherein a cutout window (13) is opened at a lower portion along the length direction. And a flat plate-shaped core mold (11) that is erected and fixed at the center of the bed (10), and is disposed so as to face the core mold (11) along the longitudinal side, and the core mold ( 11) A pair of cam drivers (1) having inclined cam surfaces (17) descending toward
6), and a pair of material support plates (20) that support the flat plate-shaped steel plate material (2 ′) from below and that are guided by the inclined cam surface (17) of the cam driver (16) and are brought into sliding downward proximity. A pair of upper surfaces that come into contact with the upper surface of the steel plate material (2 '), sandwich it from above and below together with the material support plate (20), and are guided by the inclined cam surface (17) of the cam driver (16) to descend and slide close thereto. A mold (23), and a deep groove (29a) having a length substantially equal to the length of the core mold (11) on at least one opposing surface (25) of the pair of upper molds (23). And a forming die plate (29) in which shallow grooves (29b) are continuously formed on both sides of the deep groove (29a), and a pair of upper molds (23) are approached to the lower surface of the deep groove (29a). , The core mold together with a part of the steel plate material (2 ') Press molding die apparatus being characterized in that projecting fitted projecting strip (31) along the length direction of the notch window (13) of 11). 4. The press-molding die device according to claim 3, wherein both ends of the square plate-shaped core die (11) are obliquely cut.