JP6084560B2 - Balancer device for internal combustion engine and method for manufacturing the same - Google Patents

Description

  The present invention relates to a balancer device for an internal combustion engine applied to, for example, an automobile and a manufacturing method thereof.

  As a conventional balancer device for an internal combustion engine applied to an automobile, for example, the one described in Patent Document 1 below is known. In this balancer device, a pair of balancer shafts press-fitted and fixed to a housing. However, it is configured to be rotatably supported via a known rolling bearing.

JP 2010-230129 A

  However, in the conventional balancer device for an internal combustion engine, when holding the rolling bearing, since a larger tightening allowance considering thermal expansion is required, if the housing is integrally formed as described above, There is a problem in that the burden of the press-fitting work increases and the assembly workability of the apparatus is reduced.

  On the other hand, if the housing is divided into upper and lower parts, etc., in order to secure the large tightening allowance, it is necessary to improve the axial force of the bolt that fastens the housing and the seating area of the bolt, etc. There has been a problem that the overall size of the apparatus is increased.

  The present invention has been devised in view of the actual situation of the balancer device of the conventional internal combustion engine, and is an internal combustion engine that can appropriately hold a rolling bearing without deteriorating the assembly workability of the device and increasing the size of the device. An object of the present invention is to provide a balancer apparatus.

  The present invention includes a drive-side balancer shaft that rotates based on a rotational force transmitted from a crankshaft, a driven-side balancer shaft that rotates based on a rotational force transmitted from the drive-side balancer shaft, and the two balancer shafts. A housing that is rotatably accommodated, a plurality of rolling bearings that are accommodated and fixed in the housing and that rotatably support the balancer shafts, and an outer ring of the rolling bearing that is provided in the housing and through the housing A pressing member that applies a pressing force to the housing, wherein the housing is divided into an upper housing that is disposed on the upper side in the vertical direction and a lower housing that is disposed on the lower side in the engine mounting state. The upper how except the rolling bearing housing in the axial range of the rolling bearing And the vertical gap between the opposing end faces of the lower housing is set to be larger than the vertical gap between the opposing end faces of the two housings outside the axial range of the rolling bearing. .

  The housing may be one in which the upper housing and the lower housing are integrally formed.

  According to the present invention, by providing the vertical gap, the housing can be bent and deformed by the pressing force of the pressing member. As a result, the rolling bearing in a high temperature environment can be formed without increasing the pressing force of the pressing member. The retention can be improved. As a result, it is not necessary to set a large tightening allowance in consideration of thermal expansion, and appropriate holding of the rolling bearing can be realized without deteriorating the assembly workability of the apparatus and increasing the size of the apparatus.

It is a disassembled perspective view of the balancer apparatus which concerns on this invention. It is a front view of the balancer apparatus shown in FIG. It is the arrow view seen from the A direction of FIG. It is a longitudinal cross-sectional view which follows the BB line of FIG. It is a longitudinal cross-sectional view which follows the CC line of FIG. It is a figure which shows 1st Embodiment of this invention, Comprising: It is a cross-sectional view which follows the DD line | wire of FIG. It is the arrow line view which removed the upper housing and was seen from the E direction about the balancer apparatus shown in FIG. It is a figure which shows the modification of 1st Embodiment of this invention, Comprising: It is a figure equivalent to the DD sectional view of FIG. It is a figure which shows 2nd Embodiment of this invention, Comprising: It is a figure equivalent to the DD sectional view of FIG. It is a figure which shows the modification of 2nd Embodiment of this invention, Comprising: It is a figure corresponded to the DD sectional view of FIG. It is a figure which shows 3rd Embodiment of this invention, Comprising: It is a figure equivalent to the DD sectional view of FIG. It is a figure which shows the 1st modification of 3rd Embodiment of this invention, Comprising: It is a figure equivalent to the DD sectional view of FIG. It is a figure which shows the 2nd modification of 3rd Embodiment of this invention, Comprising: It is a figure equivalent to the DD sectional view of FIG. It is a figure which shows the 3rd modification of 3rd Embodiment of this invention, Comprising: It is a figure equivalent to the DD sectional view of FIG.

Hereinafter, an embodiment in which a balancer device for an internal combustion engine according to the present invention is applied to an automobile engine will be described with reference to the drawings.
[First Embodiment]
1 to 7 show a first embodiment of a balancer device for an internal combustion engine according to the present invention. This balancer device 1 is divided and formed in a substantially halved shape as shown in FIGS. The upper housing 11 and the lower housing 12 that constitute one housing 10 by being fastened by eight bolts 18 in this embodiment, and a drive-side balancer that is rotatably supported between the housings 11 and 12. A drive shaft 13 as a shaft and a driven shaft 14 as a driven side balancer shaft, an axial middle portion of the drive shaft 13 and an axial direction one end portion of the driven shaft 14, and inclined teeth 15 a formed on the respective outer peripheral portions. , 16a mesh with each other, and the drive gear 15 and the driven gear 16 that rotate in reverse to each other, and both the housings 11, 1 Is housed and fixed between the needle bearings 17 are a plurality of rolling bearings which bearing rotatably the shafts 13 and 14, and is mainly comprised.

  The balancer device is bolted to a ladder frame (not shown) attached to the lower part of the engine (cylinder block) via a plurality of attachment portions 11a, 12a provided in both the housings 11, 12. It is housed and arranged inside an oil pan (not shown) that is attached and fixed to the ladder frame in a form that fits outside.

  The drive shaft 13 includes first to third bearing portions 21 to 21 having first to third journal portions 13a to 13c provided between the housings 11 and 12, respectively, provided at both axial ends and intermediate portions thereof. By being supported by each of the needle bearings 17 arranged and fixed at 23, the housing 10 is rotatably supported. The drive shaft 13 is provided with first and second balance weights 13d and 13e having a substantially semicircular cross section so as to sandwich the first journal portion 13a from the axial direction. Here, since the needle bearing 17 having a smaller diameter than the first balance weight 13d is fitted to the first journal portion 13a from the outside in the axial direction, the first balance weight 13d is the same as the drive shaft 13. It is configured separately and is fastened by a bolt 19 after the needle bearing 17 is fitted to the first journal portion 13a.

  On the other hand, the driven shaft 14 is formed to be short so that the axial length is about 2/3 that of the drive shaft 13, and the first and second journal portions 14a and 14b provided at both ends in the axial direction are formed as described above. By being supported by the needle bearings 17 arranged and fixed to the fourth and fifth bearing portions 24 and 25 configured between the housings 11 and 12, the housing 10 is rotatably supported. The driven shaft 14 is also provided with first and second balance weights 14d and 14e having the same mass as the drive shaft 13 so as to sandwich the first journal portion 14a from the axial direction, similarly to the drive shaft 13. The driven shaft 14 reversely rotates with respect to the drive shaft 13 based on the driving force input to the drive shaft 13 from the crankshaft (not shown), thereby exhibiting a vibration damping action that cancels the secondary vibration of the engine. Will be.

  In the upper housing 11 and the lower housing 12, as shown in FIGS. 1 and 7, opposite side surfaces of the first to third bearing portions 21 to 23 and the fourth and fifth bearing portions 24 and 25 are provided. It is comprised as the substantially 1st-3rd connection surfaces 31-33 of flat shape. Of the first to third connection surfaces 31 to 33, the first and second connection surfaces 31 and 32 are a pair of outer connection surfaces 31a connected to the outer peripheral edges of the openings of the housings 11 and 12, respectively. , 32a and inner connecting surfaces 31b, 32b provided between the first and fourth bearing portions 21, 24 and between the second and fifth bearing portions 22, 25, and a third connecting surface 33 is provided. The outer connecting surface 33c alone is used.

  Here, as for the said 1st-3rd connection surfaces 31-33, each said outer connection surface 31a-33a and the 1st-3rd connection surfaces 34-36 connected with this are set to the same height position. While these are formed so that the same plane can be configured, the inner connecting surfaces 31b and 32b are formed in a concave shape so as to be lower than the outer connecting surfaces 31a to 33a. That is, from this configuration, the housings 11 and 12 are joined so that the outer connecting surfaces 31a to 33a and the first to third connecting surfaces 34 to 36 are in close contact with each other, and the inner connecting surfaces are also connected. A predetermined vertical gap (hereinafter simply referred to as “gap”) 40 is formed between 31b and 32b. The inner connecting surfaces 31b and 32b are not only separated from each other until after the assembly of the apparatus, but when the housings 11 and 12 are fastened by the bolts 18, the housings 11 and 12 are predetermined. It is good also as a structure which closely_contact | adheres mutually when the deformation amount of this is reached, and the deformation | transformation beyond it is controlled.

  The first through third connection surfaces 31 to 33 of the lower housing 12 are respectively formed with bolt insertion holes 12b through which the bolts 18 are inserted, and the first to third connection of the upper housing 11. In the surfaces 31 to 33, female screw holes 11b into which the bolts 18 inserted into the lower housing 12 are screwed are formed. Thus, by arranging the female screw hole 11b and the bolt insertion hole 12b within the range of the connection surfaces 31 to 33, the fastening force of the bolts 18 can be directly and directly applied to the connection surfaces 31 to 33. It can be effectively applied.

  In addition, on the joint surface of the lower housing 12, lubricating oil introduced from an oil pan (not shown) through an inlet 26 formed in the second outer connecting surface 32a is provided in the first to fifth bearing portions 21 to 25. Are provided so as to connect the first to third bearing portions 21 to 23 and the fourth to fifth bearing portions 24 to 25, respectively. The lubricating oil supply groove 27 is provided only on the joint surface that does not constitute the gap 40, that is, only on the outer connecting surfaces 31a to 33a and the second and third connecting surfaces 35 and 36 connected thereto. The inner connecting surfaces 31b and 32b constituting the gap 40 are not provided. This avoids outflow of lubricating oil through the gap 40 and ensures proper lubrication of the needle bearings 17.

  The needle bearing 17 has a slightly larger outer diameter than the bearings 21 to 25, and is held and fixed in a sandwiched state by the housings 11 and 12 based on a tightening margin in the bearings 21 to 25. Yes. Particularly, when the initial tightening allowance is 0 or less, the two housings 11 and 12 are elastically deformed based on the fastening force of the bolts 18 so as to be in close contact with the bearing portions 21 to 25. Further, the outer peripheral surface of the needle bearing 17 is provided with a communication groove 17a communicating with the lubricating oil supply groove 27 and a communication hole 17b communicating the communication groove 17a with the inside of the bearing. The needle bearings 17 are lubricated through the grooves 17a and the communication holes 17b, and the lubricating oil supply grooves 27 can communicate with each other.

  Hereinafter, the manufacturing method (assembly method) of the balancer device 1 will be described with reference to FIGS.

  First, the drive shaft 13 and the driven shaft 14 are assembled. That is, after the needle bearings 17 are inserted into the journal portions 13a to 13c and 14a to 14b of the shaft bodies of the shafts 13 and 14, respectively, the first balance weights 13d are respectively attached to the rear end portions of the shaft bodies. , 14d are screwed by the bolts 19, and the drive gear 15 and the driven gear 16 are fitted and fixed to the front end portions of the shaft bodies.

  Subsequently, the drive shaft 13 and the driven shaft 14 that have been assembled are accommodated in the housing 10. That is, the needle bearings 17 assembled to the shafts 13 and 14 are sandwiched by the bearings 21 to 25 of the upper housing 11 and the lower housing 12 so that the shafts 13 and 14 are held in the housings 11. , 12 (corresponding to the first step according to the present invention).

  And the assembly of the balancer device 1 is completed by fastening the housings 11 and 12 accommodating and holding the shafts 13 and 14 with the bolts 18. That is, the bolts 18 are inserted from the lower housing 12 side into the housings 11 and 12 in which the shafts 13 and 14 are accommodated and held, and screwed into the female screw holes 11b of the upper housing 11 ( Equivalent to the second step according to the present invention).

  By such fastening, a fastening force by the bolts 18 is applied to the needle bearings 17 through the bearing portions 21 to 25 of the housings 11 and 12. That is, the housing 10 (both housings 11 and 12) bends and deforms based on the fastening force of the bolts 18, and the bending deformation is provided inside the housing 10 (between the joint surfaces of the housings 11 and 12). By spilling over the formed gap 40, the pressing force by the housings 11 and 12 based on the bending deformation is transmitted to the needle bearings 17.

  As described above, according to the balancer device 1 according to the present embodiment, the gaps 40 are provided between the joint surfaces of the housings 11 and 12. In addition to the fastening force by the bolt 18, a pressing force based on the bending deformation of the housings 11 and 12 generated based on the fastening force of the bolts 18 can be applied. Therefore, the holding performance of the needle bearings 17 in a high temperature environment can be improved without increasing the cost and the fastening force of the bolts 18. As a result, it is not necessary to set a large tightening allowance in consideration of thermal expansion, and it is possible to realize appropriate holding of the needle bearings 17 without deteriorating the assembly workability of the apparatus and increasing the size of the apparatus. it can.

  In particular, in the present embodiment, the gap 40 is provided between the inner connecting surfaces 31b and 32b and fastened via the outer connecting surfaces 31a to 33a, that is, fastened at a relatively outer position. Since this is done, the fastening force of each bolt 18 is effectively utilized, and the housings 11 and 12 can be effectively fastened. As a result, the fastening with a relatively small number of bolts 18 is possible, and the number of the bolts 18 can be reduced, the assembly workability can be improved by the reduction, and the seating performance of the bolts 18 can be improved. The

  Furthermore, since the bolts 18 are configured to penetrate the gaps 40, the fastening force of the bolts 18 can be used more effectively, and the housings 11 and 12 can be easily bent. , 12 is used to improve the holding performance of the needle bearings 17 based on the larger deflection deformation.

  In the present embodiment, since the housing 10 is divided into the upper housing 11 and the lower housing 12, the needle bearings 17 are connected to the shafts 13 as an integrated structure. Compared with the case of press-fitting together with the needle bearings 17, 14, the complicated press-fitting work of the needle bearings 17 can be avoided, the assembly workability of the apparatus can be facilitated, the restrictions on the assembly work of the apparatus are reduced, The layout can be improved.

  In addition, in adopting such a divided structure, in the present embodiment, the bolts 18 that fasten the housings 11 and 12 also function as pressing members that apply a pressing force to the needle bearings 17. It has become. That is, since the existing bolts 18 used for fastening the housings 11 and 12 can be effectively used for holding the needle bearings 17, it is not necessary to separately provide the pressing member, and the structure of the apparatus is simplified. It is also used for improvement of assembly and assembly.

As described above, in the first embodiment described above, the configuration in which the gap 40 is disposed on each of the inner coupling surfaces 31b and 32b has been described as an example. However, the present invention is not limited to such an inner arrangement structure. As shown in FIG. 8, it is also possible to arrange the gap 40 on each of the outer connecting surfaces 31a to 33a. In the case of adopting such an arrangement structure, the fastening force of each bolt 18 is more effectively utilized, and the housings 11 and 12 are easily bent. As a result, the housings 11 and 12 are more flexibly deformed. This is used to improve the holding performance of the needle bearings 17 based on the above. In other words, in the case of such an arrangement structure, it is possible to reduce the fastening force of the bolts 18 necessary for obtaining a certain holding property of the needle bearings 17, thereby reducing the size of the bolts 18. The size of the apparatus can be reduced by reducing the size of the connecting surfaces 31 to 33, and the layout of the apparatus can be improved.
[Second Embodiment]
FIG. 9 shows a second embodiment of a balancer device for an internal combustion engine according to the present invention, in which the configuration of the housing 10 according to the first embodiment is changed. In this embodiment as well, the basic configuration of the balancer device 1 is the same as that of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals and will be described in detail. Is omitted.

  That is, in this embodiment, unlike the first embodiment in which the housing 10 is divided into an upper housing 11 and a lower housing 12, the housing 10 is integrally formed and corresponds to the upper housing 11. The upper portion 10a and the portion corresponding to the lower housing 12 are configured as a lower portion 10b. More specifically, the upper part 10a is configured above the axis of each needle bearing 17 (see the dashed line in FIG. 9), and the lower part 10b is configured below the axis of each needle bearing 17. is there.

  In the housing 10, a gap 40 similar to that of the first embodiment is provided at a substantially central position of the boundary between the upper part 10 a and the lower part 10 b so as to penetrate the gap 40. The bolt 20 inserted through the bolt insertion hole 10c formed penetrating below the gap 40 is screwed into the female screw hole 10d formed above the gap 40.

  Thus, even when the housing 10 is integrally formed, by providing the gap 40 inside the housing 10, the housing 10 is deformed by the fastening force of the bolts 20, and based on the deformation. Thus, a pressing force by the housing 10 is applied to each needle bearing 17, and substantially the same function and effect as in the first embodiment can be achieved.

  In particular, in the present embodiment, since the housing 10 is integrally formed, the connecting operation of the housing 10 becomes unnecessary, so that the number of man-hours for assembling the apparatus can be reduced and the cost of the apparatus can be reduced.

  In the present embodiment, the gap 40 is provided at the center of the housing 10 corresponding to the inner connecting surfaces 31b and 32b. However, the gap 40 is the same as in the first embodiment. For example, as shown in FIG. 10, it is also possible to provide at the inner and outer positions of the housing 10 corresponding to the outer connecting surfaces 31a to 33a. In such a configuration, the housing 10 is bent and deformed by the fastening force of the mounting bolt 30 for mounting the balancer device 1 to the ladder frame (not shown), and a pressing force is applied to each needle bearing 17. Can do.

That is, in such a configuration, the same operational effects as those described in the first embodiment can be obtained, such as more effective use of the fastening force of each bolt 18 and improvement of the holding performance of each needle bearing 17. . In the case of this configuration, the housing 10 can be bent and deformed by the mounting bolts 30, so that the bolts 20 need not be provided separately, and the number of assembly steps and costs can be reduced by reducing the number of parts of the apparatus. There is also a merit that can be achieved.
[Third Embodiment]
FIG. 11 shows a third embodiment of a balancer device for an internal combustion engine according to the present invention, in which the configuration of the housing 10 according to the first embodiment is changed. In this embodiment as well, the basic configuration of the balancer device 1 is the same as that of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals and will be described in detail. Is omitted.

  That is, in the present embodiment, an intermediate member 41 having a larger elastic modulus than the housing 10 such as a resin material is inserted into the gap 40 formed between the joint surfaces of the upper housing 11 and the lower housing 12, The gap 40 is almost filled with the intermediate member 41.

  Due to such a configuration, in the present embodiment as well, both the housings 11 and 12 are bent and deformed with the fastening of the housings 11 and 12 by the respective bolts 18. As a result, the two housings 11 and 12 are based on the bending deformation. A pressing force is applied to each of the needle bearings 17, and the same effect as the first embodiment can be achieved.

  In particular, in the present embodiment, as a result of the intermediate member 41 being compressed based on the bending deformation of the two housings 11 and 12 at the time of fastening, the intermediate member 41 comes into elastic contact with both the housings 11 and 12. Therefore, it is possible to improve the joining property of the housings 11 and 12.

  Furthermore, in the case of this embodiment, since the intermediate member 41 is inserted, the spring constant of the entire housing 10 can be increased. As a result, both the housings 11, 12 can be promoted, and the axial width and thickness of each of the bearing portions 21 to 25 can be reduced. Thereby, each said bearing parts 21-25 can be reduced in size by the said reduction | decrease, and it also serves for size reduction of an apparatus.

  In the present embodiment, as described above, the housing 10 is divided, and the gap 40 is provided between the inner connection surfaces 31b and 32b. The housing 10 may have an integral structure as shown in FIGS. The gap 40 can also be provided at positions corresponding to the outer connecting surfaces 31a to 33a shown in FIG. 12 and the outer connecting surfaces 31a to 33a shown in FIG. Needless to say, the same effects as those described in the embodiments can be obtained.

  The present invention is not limited to the configuration of each of the above embodiments. For example, the present invention is not limited to the specific configuration of the housing 10 and the shafts 13 and 14 that are not directly related to the features of the present invention. Needless to say, the specific shape, quantity, size, and the like of the gap 40, which is a feature of the above, can be freely changed according to the specifications of the internal combustion engine to be applied as long as the above-described effects can be obtained.

  In addition, in the said 1st, 3rd embodiment, although the said each bolt 18 illustrated the structure which penetrates the said clearance gap 40, about the arrangement | positioning of each said bolt 18, the said housing 10 (both housings 11 and 12). As long as it can be flexibly deformed, it may be set outside the region where the gap 40 is formed.

  In the first and third embodiments, the bolts 18 and the like are used to connect the housings 11 and 12, but the present invention is not limited to the bolts 18 and the like. , 12 can be replaced as long as they can be connected while being bent.

DESCRIPTION OF SYMBOLS 1 ... Balancer apparatus 10 ... Housing 11 ... Upper housing 12 ... Lower housing 13 ... Drive shaft (drive side balancer shaft)
14 ... Driven shaft (driven balancer shaft)
17 ... Needle bearing (rolling bearing)
18 ... bolt (pressing member)
40: Clearance (Vertical clearance)

Claims (8)

A drive-side balancer shaft that rotates based on the rotational force transmitted from the crankshaft;
A driven-side balancer shaft that rotates based on a rotational force transmitted from the drive-side balancer shaft;
A housing that rotatably accommodates both the balancer shafts;
A plurality of rolling bearings housed and fixed in the housing and rotatably bearing the balancer shafts;
A pressing member that is provided in the housing and applies a pressing force to the outer ring of the rolling bearing through the housing;
With
The housing is divided into an upper housing disposed on the upper side in the vertical direction and a lower housing disposed on the lower side in the engine mounting state,
The vertical gap between the opposing end surfaces of the upper housing and the lower housing excluding the rolling bearing housing in the axial range of the rolling bearing is between the opposing end surfaces of the two housings outside the axial range of the rolling bearing. A balancer device for an internal combustion engine, wherein the balancer device is set so as to be larger than the vertical clearance of the internal combustion engine. The balancer device for an internal combustion engine according to claim 1,
The vertical gap between the opposing end surfaces of the upper housing and the lower housing is set so that the inner side is larger than the horizontal outer side of each rolling bearing adjacent to the width direction of the housing. A balancer device for an internal combustion engine. The balancer device for an internal combustion engine according to claim 2,
The balancer device for an internal combustion engine, wherein the pressing member is disposed at a location where a vertical gap between the two housings is set large. The balancer device for an internal combustion engine according to claim 3,
The balancer device for an internal combustion engine, wherein the pressing member is constituted by a bolt that fastens the upper housing and the lower housing. The balancer device for an internal combustion engine according to claim 4,
The balancer device for an internal combustion engine, wherein the housing has an oil supply path for supplying oil to a housing portion of the rolling bearing. The balancer device for an internal combustion engine according to claim 1,
The vertical gap between the opposing end surfaces of the upper housing and the lower housing is set so that the outer side is larger than the inner side in the horizontal direction of the rolling bearings adjacent in the width direction of the housing. A balancer device for an internal combustion engine. A drive-side balancer shaft that rotates based on the rotational force transmitted from the crankshaft;
A driven-side balancer shaft that rotates based on a rotational force transmitted from the drive-side balancer shaft;
A housing that rotatably accommodates both the balancer shafts;
A rolling bearing which is housed and fixed in the housing and rotatably supports the balancer shafts;
A pressing member that is provided in the housing and applies a pressing force to the outer ring of the rolling bearing through the housing;
With
The housing is integrally configured with an upper part above the axis of the rolling bearing as an upper part and a lower part as a lower part,
A portion between the upper portion and the lower portion in the axial range of the rolling bearing and excluding the accommodating portion of the rolling bearing has a larger vertical clearance than a portion outside the axial range of the rolling bearing. A balancer device for an internal combustion engine, characterized by being formed. A drive-side balancer shaft that rotates based on the rotational force transmitted from the crankshaft;
A driven-side balancer shaft that rotates based on a rotational force transmitted from the drive-side balancer shaft;
A housing that rotatably accommodates both the balancer shafts;
A plurality of rolling bearings housed and fixed in the housing and rotatably bearing the balancer shafts;
A pressing member that is provided in the housing and applies a pressing force to the outer ring of the rolling bearing through the housing;
With
The housing is divided into an upper housing disposed on the upper side in the vertical direction and a lower housing disposed on the lower side in the engine mounting state,
The vertical gap between the opposing end surfaces of the upper housing and the lower housing excluding the rolling bearing housing in the axial region of the rolling bearing is between the opposing end surfaces of the two housings outside the axial region of the rolling bearing. A balancer device manufacturing method for an internal combustion engine set to be larger than the vertical clearance of
A first step of accommodating the drive-side balancer shaft and the driven-side balancer shaft into the housing;
A method of manufacturing a balancer device for an internal combustion engine, comprising: a second step of attaching the pressing member between the upper housing and the lower housing.

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