JPH0960919A - Switch box arrangement structure for air conditioner - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To improve the size of an entire switch box while accommodating a required number of electric parts by improving the switch box. A switch box (14) housed in an air conditioner casing is formed of a resin box-shaped one side surface of which is open. A partition plate 23 for partitioning the inside of the air conditioner casing into an air circulation space A and a switch box installation space B is provided.
The switch box 14 is inserted from below into the switch box installation space A, and the opening is closed by the partition plate 23 with the switch box 14 being installed at a predetermined position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch box provided in an air conditioner such as a ceiling-embedded type air conditioner, and more particularly to a measure for downsizing the switch box.

[0002]

2. Description of the Related Art Conventionally, for example, an actual Kaihei 5-59118 is used.
As disclosed in Japanese Patent Laid-Open Publication No. JP-A-2004-242242, a ceiling-embedded air conditioner includes a main body casing installed in a space above the ceiling,
A decorative panel that is installed on the ceiling surface and that has a suction port and a blowout port that communicate with the internal space of the main body casing, and a blower is disposed in the central portion inside the main body casing, and an air blower downstream of the blower. A heat exchanger is arranged on the side. Then, by driving the blower, the indoor air sucked into the main body casing from the suction port of the decorative panel is blown out from the blower toward the heat exchanger, and the temperature is adjusted when passing through the heat exchanger. Then, it is supplied to the indoor space from the outlet of the decorative panel.

In addition, a switch box accommodating electric parts for controlling each device is provided inside the main body casing of this type of air conditioner. In addition, as a disclosure of the disposition state of this switch box, it is disclosed in Japanese Utility Model Laid-Open No. 5-59.
There is a 125 publication. In this publication, FIG. 16 and FIG.
As shown in FIG. 3, the switch box (a) is L-shaped. In other words, the box body made of sheet metal formed in L shape
A transformer (c), a capacitor (d), a terminal block (e), etc. are attached to (b), and the lower side of the lid is made of sheet metal and is formed into an L shape.
By covering with (f), the inside of the switch box (a) is formed into a substantially sealed space. And electrical parts
For maintenance of (c, d, e), etc., switch box
(a) The whole is pulled down and the lid (f) is removed from the box body (b) to perform maintenance of the electric parts (c, d, e). In addition, (g) in FIG. 16 is a heat exchanger,
(h) is a drain pump.

[0004]

However, in the structure of the above publication, since the switch box is made of sheet metal, it is not possible to secure a large degree of freedom in the arrangement position of the electric parts. However, there was a limit to making the switch box compact as a whole.

The present invention has been made in view of this point, and an object of the present invention is to improve the switch box so that the switch box as a whole can be made compact while allowing the required number of electric components to be accommodated therein.

[0006]

In order to achieve the above-mentioned object, the present invention comprises a switch box made of a resin molded product, and the open part of the switch box is mounted on an air conditioner casing at the same time. The inside of the switch box was closed to form a substantially sealed space.

More specifically, the invention according to claim 1 is, as shown in FIGS. 5 and 6, a switch box housed in an internal space of an air conditioner casing (2, 6) and provided with electric parts therein.
It is based on the arrangement structure of (14). Then, the switch box (14) is provided with a box body (15) consisting of a box body of a resin integrally molded product with only a part of the side surface opened, and the air conditioner casing (2, 6) is provided with the box body. A configuration is provided in which a closing member (23) for closing the open portion of the box body (15) is provided in a state where the (15) is accommodated in a predetermined arrangement position.

As described above, since the box body (15) is made of a resin integrally-molded box body, the switch box itself can have a complicated shape. Therefore, the box body (15) It is possible to freely form a large number of locations where electric parts can be arranged inside the box
(15) It is possible to accommodate a large number of electric components inside and to reduce the size thereof.

According to a second aspect of the invention, there is provided a switch box arrangement structure for an air conditioner according to the first aspect,
The closing member is a partition plate (23) that partitions the internal space of the air conditioner casing (2, 6) into an air circulation space (A) and a switch box installation space (B) that houses the box body (15). The partition plate (23) is provided with guide means (23e) for guiding the insertion of the box body (15) into the switch box installation space (B).

With this structure, the air conditioner casing (2, 2) is attached to the closing member (23) for closing the open portion of the box body (15).
A function of partitioning the internal space of 6) into the air circulation space (A) and the switch box installation space (B) can be provided.
The number of parts can be reduced by providing both functions to one member.

According to a third aspect of the present invention, in the switch box arrangement structure of the air conditioner according to the first or second aspect, the wall surface (17a) facing the indoor side of the box body (15).
Is a mounting portion to which a part of the electric component (26) is attached, and the side edge of the mounting portion (17a) covers the part of the electric component (26) from the indoor side and is between the mounting portion (17a). A lid (25) that forms an electric component disposition space (C) is rotatably supported by the box body (15), and the lid (25) is a part of the electrical component (26). A holding means (25c) for holding the above in a state of being covered is provided.

With this structure, the holding state of the holding means (25c) is released during maintenance of the electric component (26) mounted on the mounting portion (17a) of the box body (15), and the lid body is released.
This can be done by rotating the (25) inward of the box body (15). In other words, maintenance of the electric component (26) can be performed without removing the switch box from the air conditioner casing.

The invention according to claim 4 is the above-mentioned claim 1, 2
Alternatively, in the switch box arranging structure of the air conditioner according to 3, the one end is connected to a part of the electric component (21) housed inside the box body (15), and the other end is connected to the box body ( The outer surface (16c) that penetrates one wall part (16) of the 15)
A metal heat radiating plate (22) is provided along the outer surface (16c) so as to be in close contact with the outer surface (16c).

With this configuration, the heat generated by the electric component (21) is radiated to the outside of the box body (15) by the heat radiating plate (22), and heat damage to the electric components inside the box body (15) is avoided. The heat sink (22) also has a function of closely contacting the outer surface (16c) of the one wall portion (16) of the box body (15) and preventing the deformation of the one wall portion (16). By box body
(15) Overall rigidity is secured.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a ceiling-embedded air conditioner (1) according to the present embodiment, FIG. 2 is a bottom view thereof (a view as seen from the indoor side when installed on the ceiling surface), and FIG. FIG. 3 is an enlarged view of a cross section taken along line III-III in FIG. 2.
As shown in FIG. 3, the air conditioner (1) has a ceiling
The main casing (2), which is inserted into the opening (H) formed in (R) and opens downward, is installed in the space above the ceiling (S). The main casing (2) includes a top plate (2a) and side plates (2b) extending downward from the outer edge of the top plate (2a). Further, a blower (3) having an air outlet (3a) that opens upward is disposed in the center of the main body casing (2). This blower (3) consists of a sirocco fan in which a fan rotor (not shown) is housed in a resin fan casing (3b), and blows air upward from the air outlet (3a) as the fan rotor rotates. . Also this blower
In contrast to (3), heat exchangers (4, 4 ') are arranged on both the left and right sides of FIG. 3 (both sides in the width direction of the air conditioner). This heat exchanger (4, 4 ') is connected to the outdoor unit via a refrigerant pipe (12) (see FIG. 1), and functions as an evaporator during cooling operation and as a condenser during heating operation, and the blower (3 The heat is exchanged with the air blown from the air conditioner to adjust the temperature of the air. Further, a drain pan (5) is arranged below the heat exchanger (4), and the condensed water generated in the heat exchanger (4) during the cooling operation is collected as a drain to the drain pipe (13). It is designed to be discharged.

A decorative panel (6) is attached to the lower end of the body casing (2). This Makeup Panel (6)
Has an opening (6a) formed in the center thereof.
A cover panel smaller than the opening (6a) in the center of a)
(7) is provided, and on both outer sides of the cover panel (7),
Air inlets (6b, 6b) for introducing indoor air into the main casing (2) are formed. In other words, the air inlets (6b, 6b) are the same as those shown in FIGS. 1 and 2.
The air conditioner (1) is provided at two locations, and each extends in the longitudinal direction of the air conditioner (1) (left-right direction in FIG. 2). Also,
As shown in FIG. 3, the cover panel (7) is provided with hook portions (7a, 7a) whose both side edges are curved. The hook portions (7a, 7a) are attached to the decorative panel (6). It is integrally assembled to the decorative panel (6) in a state where it is locked by the locking pins (6c, 6c) extending in the horizontal direction and prevented from falling. In addition, the air inlet (6
An air filter (8) is provided at a position facing b, 6b) to prevent dust from entering the body casing (2).

Further, air outlets (6d, 6d) are formed at both side edges (both side edges in the vertical direction in FIG. 2) of the decorative panel (6). The air outlets (6d, 6d) are parallel to the outer member (9) forming the outer edge of the decorative panel (6) and the inner position at a predetermined distance from the outer member (9). It is formed between the extending inner member (10).
Then, the conditioned air generated in the heat exchanger (4) is supplied to the indoor space by the air outlets (6d, 6d). In this way, the air inlet (6
b), air filter (8), blower (3), heat exchanger (4,4 '),
An air flow passage (A) is formed across the air outlet (6d).

At the center of each air outlet (6d, 6d), there is a horizontal blade (6) capable of changing the direction of the conditioned air blown from the air outlets (6d, 6d) into the indoor space. 11) is rotatably arranged. The horizontal blade (11) is a long plate made of resin, and support pins (not shown) project from both sides in the longitudinal direction of the plate, and the support pins are rotatably attached to the decorative panel (6). It is supported, and is rotated about the support pin by driving a motor (not shown).

Next, the structure of the switch box (14), which is a feature of this embodiment, and the arrangement structure thereof will be described.
FIG. 5 shows a state in which the cover panel (7) of the air conditioner (1) is removed. The switch box (14) is arranged in the vicinity of the left end in FIG. 5 (in FIG. 5, only the lower surface of the switch box (14) faces downward). In addition, FIG. 6 is a view of the peripheral portion of the arrangement portion of the switch box (14) as viewed from above. In this way, the switch box (14) is housed in the switch box installation space (B) formed by bending a part of the drain pan (5) outward.

The structure of the switch box (14) will be described below. The switch box (14) is composed of a box-shaped box body (15) formed of a resin such as polystyrene or polypropylene, and a box lid (25) rotatably provided below the box body (15). ing. FIG.
Is a front view of the box body (15), and FIG. 7 is VII- in FIG.
FIG. 8 is a sectional view taken along line VII, and FIG. 8 is VIII-VIII in FIG.
4 is a sectional view taken along line IX-IX in FIG. 4, FIG. 10 is a view taken along arrow X in FIG. 4, FIG. 11 is a view taken along arrow XI in FIG. 4, and FIG. The XII arrow views at are shown respectively. As shown in each of these figures, the main box body (15) includes an upper plate portion (16), a lower plate portion (17), a pair of left and right side plate portions (18, 19) and each of these plate portions (16, 17, A box body that is integrally formed with a mounting plate portion (20) for mounting electrical parts that is erected on (18, 19), so that only one side (front side in the vertical direction of the paper in FIG. 4) is open. Is formed by. Further, on the inner surface of the mounting plate portion (20), there are screw holes (20a, 20a, ...) For mounting electric components such as transformers, capacitors, and printed circuit boards (not shown), and engaging members for locking the harness. Stops (20b, 20b, ...) Are formed at a plurality of locations (in FIG. 7, the arrangement state of the printed circuit board P is shown by imaginary lines). And the internal space (15a) of this box body (15)
In the figure, the light electric component is arranged on the right side and the strong electric component is arranged on the left side. In particular, the screw hole (20a ') formed in the vicinity of the corner on the upper left side in FIG. 4 is for mounting the power transistor (21).

As a feature of the mounting structure of the power transistor (21), the upper plate portion (16) of the box body (15) is shown in FIG.
As shown in 0, one end is formed with a slit (16a) that opens to the box opening side (upper side in FIG. 10),
The power transistor (21) is supported by a heat dissipation plate (22) that passes through the slit (16a) and extends to the outside of the upper plate portion (16). As shown in FIGS. 4 and 6 (shown in phantom in FIG. 4), the heat dissipation plate (22) is in contact with the power transistor (21) and one end (the right end in FIG. 4) faces the slit (16a). Contact part (22a), a relatively short extension (22b) extending from one end of this contact part (22a) to the outside of the upper plate part (16) through the slit (16a), and this extension part The power transistor (21) is provided with a heat dissipation part (22c) extending from the outer end of (22b) to the right side of FIG. 4 along the outer surface (16c) of the upper plate part (16).
The heat generated by the heat is radiated from the heat radiating portion (22c) through the contact portion (22a) and the extension portion (22b). This allows
It is designed to prevent other electric parts from being adversely affected by the abnormal temperature rise in the internal space (15a) of the box. Also, the heat dissipation part (22c) of this heat dissipation plate (22) is the upper plate part.
Since it is in close contact with the outer surface (16c) of (16), this upper plate (16)
The deformation of the box body (15) is prevented, and thereby the rigidity of the entire box body (15) is ensured to be high.

Next, the assembling structure of the box body (15) to the body casing (2) will be described. Each side plate (18, 19) of the box body (15) has an outwardly extending flange.
(18a, 18b, 19a, 19b) are formed, and at the lower end of the flange (18b, 19b) located on the lower side, as shown in FIG. 8, FIG. 10 and FIG. Stop (18c, 19c)
Is formed by bending, and U-shaped locking holes (18d, 19d), one of which is open, are formed in the locking pieces (18c, 19c).

On the other hand, as shown in FIG. 6, the box body (1
5) Space where the air conditioner is located in the center of the space (B) (right side in Fig. 6)
A partition plate (23) is arranged in the partition. This partition (23)
A plate member for partitioning the inside of the main casing (2) into the air flow passage (A) and the switch box installation space (B).
Further, the partition plate (23) is a partition plate main body (23a) that closes the open part of the box main body (15) in the assembled state.
And a mounting flange portion (23b) bent from the upper end of the partition plate body portion (23a) to the air conditioner center side with a small dimension,
It is bent to the outside of the air conditioner at both sides in the horizontal direction of the partition plate main body (23a), and with the box main body (15) assembled, the locking pieces (18c, 19c) abut and have a U-shape. Locking hole (1
8d, 19d) box support (23d) with bolt holes (23c) facing each other, and the flanges (18a, 18b,
19a, 19b) and a guide portion (23e) as guide means for contacting the outer edge of the box body (15) and guiding the vertical movement of the box body (15) in the space (B). And this partition (2
3), the flange (23b) is the top plate (2) of the main casing (2).
It is screwed to a), and with the locking pieces (18c, 19c) of the box body (15) in contact with the lower surface of the box support (23d), the locking holes (18d, 19d) and bolt holes. The box body (15) is supported by screwing screws from below over (23c). That is, the box body (15) is supported by the body casing (2) via the partition plate (23).

Further, as shown in FIGS. 4 and 10, the upper plate portion (16) of the box body (15) has an extension portion (16b) extending downward from the edge of the box opening side with a small size. Has been drooped, and the top plate corresponding to this extension (16b)
A support plate (not shown) extending downward from (2a) is provided, and the extension part (16b) can be locked to the support plate. In other words, when performing maintenance on the electrical components housed in the internal space (15a), the box body (1
By pulling down 5) and engaging the extension portion (16b) with the support plate, the box body (15) can be brought into a suspended state, and the maintainability is improved.

As shown by phantom lines in FIG. 11, a plurality of terminal blocks (26, 26) are arranged on the outside of the lower plate part (17) of the main box body (15) through mounting plates (not shown). It is set up.

Further, at the box opening side end of the lower plate portion (17) of the box body (15), a lid supporting piece (2
4) is bent and formed. Locking holes (24a, 24a) for locking the box lid (25) are formed at two positions on the left and right sides of the lid support piece (24). As shown in FIGS. 13 and 14, the box lid (25) has locking portions (25a, 25a) that are locked to the locking holes (24a, 24a) at one side edge thereof to form a hinge mechanism, As shown in FIG. 5, it is formed at the center of the side edge opposite to the one side edge where the locking portions (25a, 25a) are formed, and the main casing side (specifically, the drain pan (5) A locking projection (25c) as a holding means is integrally formed with a locking hole (25b) that is detachably locked to the lower surface. This locking protrusion
As a structure for attaching and detaching the drain pan (5) by the (25c), a protrusion (not shown) which can engage the edge of the engaging hole (25b) is formed on the lower surface of the drain pan (5). It can be attached and detached by the unlocking operation.

With such a structure, as shown in phantom in FIG. 12, the box lid (25) is locked in the box body (15) in the horizontal direction, that is, the box body. When rotated so that it is parallel to the lower plate part (17) of (15), the lower plate part of this box lid (25) and box body (15)
A small gap (C) is formed between (17).
That is, the lower side of the terminal blocks (26, 26) arranged on the lower plate portion (17) of the box body (15) is covered with the box lid (25).

Next, the air conditioner configured as described above
The operation of (1) will be described. During this air conditioning operation, the room air sucked into the main casing (2) from the air suction port (6b) along with the drive of the blower (3) has its dust removed by the air filter (8) and then blower. After passing through (3), it is passed to the heat exchanger (4, 4 '). And this heat exchanger
At (4,4 '), heat is exchanged with the refrigerant to adjust temperature (cooling in cooling operation, heating in heating operation)
After that, the air is blown from the air outlet (6d) into the indoor space to perform air conditioning of the indoor space.

Next, the maintenance work of the box body (15) will be described. First, when performing maintenance or wiring change of the terminal block (26), as shown in FIG.
With the cover panel (7) removed from the air conditioner (1), hold the locking protrusion (25c) of the box lid (25) and rotate it downward to move the box lid (7). The lower part (17a) of the lower plate part (17) of the box body (15) faces the room by rotating the box body (15) about the hinge portion with respect to the box body (15). This allows the box body (15)
Maintenance work of the terminal block (26) or wiring change work can be carried out without pulling down, and the workability is good.

During maintenance of the electric parts housed in the box internal space (15a), the box body (1
The screw fastening 5) to the partition plate (23) is removed, and the entire switch box (14) is moved downward. This move
The outer edge of each of the flanges (18a, 18b, 19a, 19b) of the box body (15) comes into contact with the guide portion (23e) of the partition plate (23), and is lowered while being guided thereby. And
After this descent, the extension part (16b) formed on the upper plate part (16) is locked to the support plate extending from the top plate (2a), so that the box body (15) is suspended and a predetermined amount is obtained. Perform maintenance work.

As described above, in this embodiment, since the box body (15) is made of resin, it is possible to make it into a complicated shape as compared with the conventional one made of sheet metal. Therefore, since it is possible to form freely and a large number of places where the electric components can be arranged inside the box body (15), it is possible to accommodate a large number of electric components while making the box body (15) small. With the downsizing of the box body (15), the overall size of the air conditioner can be reduced.

Further, the partition plate (23) has a function of closing the open portion of the box body (15), and the inner space of the body casing (2) is an air circulation space (A) and a switch box installation space.
Since it also has the function of partitioning into (B), it is possible to reduce the cost associated with the reduction in the number of parts.

The switch box according to the present embodiment
In (14), an adapter P plate for optional equipment can be attached. This adapter P plate is supported by the P plate mounting plate (28) shown in FIG. 15, and as shown by the phantom line in FIG. 7, this P plate mounting plate (28) is the open side edge of the box body (15). It is constructed so as to span the upper plate portion (16) and the lower plate portion (17) in the vicinity thereof. That is, when the P-plate mounting plate (28) is attached to the box body (15), the P-plates are arranged in a two-layer structure as shown by phantom lines in FIG. It is possible to arrange the electric components while using them.

In this embodiment, the case where the present invention is applied to the ceiling-embedded air conditioner has been described.
The present invention is not limited to this, and is applicable to various air conditioners such as a ceiling hanging type and a wall hanging type.

[0035]

As described above, according to the present invention, the following effects can be obtained. According to the first aspect of the present invention, the switch box is provided with a box main body made of a resin integrally-molded box whose only one side surface is open, and the box main body is housed at a predetermined position. Since the open portion is closed by the closing member in this state, the switch box itself can have a complicated shape, and a large number of places where electrical parts can be arranged are formed inside the box body freely. As a result, the box body can be made compact, and the air conditioner as a whole can be made compact. In addition, since the inside of the box body is made into a substantially sealed state by the closing member, the adverse effect on the electric parts due to the intrusion of dust into the inside of the box body is avoided.

According to the second aspect of the present invention, the closing member has a function of closing the open portion of the box body and a function of partitioning the internal space of the air conditioner casing into the air circulation space and the switch box installation space. Because I had them together,
The cost can be reduced by reducing the number of parts.

According to the third aspect of the present invention, a lid for covering the electric parts mounted on the mounting portion facing the indoor side of the box main body from the indoor side is provided rotatably with respect to the box main body. Since the state in which the parts are covered can be held by the holding means, maintenance of the electric parts can be performed only by releasing the holding state of the holding means and rotating the lid body inwardly with respect to the box body, and the switch box Since it is not necessary to take out the air conditioner from the air conditioner casing, good workability can be obtained.

According to the fourth aspect of the present invention, the heat radiation plate connected to the electric component has a function of radiating the heat from the electric component to the outside of the box body and a function of preventing deformation of one wall of the box body. Therefore, it is possible to avoid the heat damage to the electric parts inside the box body and to secure the rigidity of the box body by one member.

[Brief description of drawings]

FIG. 1 is a perspective view of a ceiling-embedded air conditioner according to an embodiment of the present invention.

FIG. 2 is a view of the air conditioner viewed from the indoor side.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a front view of a switch box.

FIG. 5 is a perspective view of the air conditioner with a cover panel removed.

FIG. 6 is a plan view showing the periphery of a switch box housing portion.

FIG. 7 is a sectional view taken along line VII-VII of FIG.

8 is a sectional view taken along line VIII-VIII of FIG.

9 is a sectional view taken along line IX-IX in FIG.

10 is a view on arrow X in FIG. 4. FIG.

FIG. 11 is a view on arrow XI of FIG. 4.

FIG. 12 is a view on arrow XII in FIG.

FIG. 13 is a diagram showing a surface of a box lid.

FIG. 14 (a) shows the back surface of the box lid, and (b) shows (a).
FIG.

FIG. 15 is a diagram showing an adapter P-plate mounting plate.

FIG. 16 is a diagram showing a position of a switch box in a conventional example.

FIG. 17 is an exploded perspective view of a switch box in a conventional example.

[Explanation of symbols]

 (1) Ceiling embedded air conditioner (2) Main body casing (6) Decorative panel (14) Switch box (15) Box body (16) Upper plate part (16c) Outer surface (17) Lower plate part (17a) Lower surface (Mounting part) (21) Power transistor (22) Heat sink (23) Partition plate (closure member) (23e) Guide part (guide means) (25) Box lid (cover) (25c) Locking protrusion (holding means) ) (26) Terminal block (A) Air flow passage (B) Switch box installation space (C) Electrical component installation space

Claims (4)

[Claims] 1. A switch box (14) housed in an internal space of an air conditioner casing (2, 6) and equipped with electric parts therein.
In the arrangement structure of (1), the switch box (14) includes a box body (15) made of a resin integrally-molded box whose only one side surface is open, and the switch box (14) is provided in the air conditioner casing (2, 6). Is a state in which the box body (15) is housed in a predetermined arrangement position.
A switch box arrangement structure for an air conditioner, characterized in that a closing member (23) for closing the open portion of (5) is provided. 2. The partition member for partitioning the inner space of the air conditioner casing (2, 6) into an air circulation space (A) and a switch box installation space (B) for housing the box body (15). A plate (23), characterized in that the partition plate (23) is provided with guide means (23e) for guiding the insertion of the box body (15) into the switch box installation space (B). The switch box arrangement structure for an air conditioner according to claim 1. 3. The wall surface of the box body (15) facing the indoor side
The part (17a) is a mounting part for mounting a part of the electric part (26), and the part of the electric part (26) is mounted on the side edge of the part (17a) so as to cover the part from the indoor side. A lid (25) forming an electric component disposition space (C) with the portion (17a) is provided rotatably supported with respect to the box body (15). 3. A switch box arrangement structure for an air conditioner according to claim 1 or 2, further comprising: a holding means (25c) for holding the () in a state of covering a part of the electric component (26). 4. One end of the box body (15) is connected to a part of an electric component (21) housed inside the box body (15), and the other end of the box body (15) has a wall (16). Through its outer surface (16
The switch box arrangement for an air conditioner according to claim 1, 2 or 3, characterized in that a metal heat dissipation plate (22) extending along c) so as to be in close contact with the outer surface (16c) is provided. Construction structure.