Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-07-09
2001-02-06
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S058000, C310S06000A, C310S06000A, C310S064000
Reexamination Certificate
active
06184602
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a rectifying apparatus for an automotive AC generator.
Increasing an effective capacity in a passenger compartment is an important matter to be realized for recent automotive vehicles. Thus, it is earnestly required to reduce the space of an engine room. Automotive AC generators are one of objects to be downsized. Accordingly, an important subject is to improve the cooling performance of a rectifying apparatus for an automotive AC generator, while maintaining adequate cooling efficiency against deterioration of temperature environment in the engine room or downsizing of the automotive AC generator itself.
For example,
FIG. 11
shows a conventional automotive AC generator. According to this conventional automotive AC generator, both of positive and negative fins
101
and
102
mount rectifying elements
100
thereon. These fins
101
and
102
are arranged parallel to each other in an axial direction. A protecting cover
103
has two cooling air inlets
104
opened at predetermined portions near the rectifying elements
100
. External air is directly introduced to the rectifying elements. More specifically, the back surfaces of the fins
101
and
102
are cooled by the cooling air.
However, according to the arrangement of the above-described conventional rectifying apparatus, the cooling air is introduced toward the centers of the rectifying elements
100
but directly guided to the back surfaces of the cooling fins
101
and
102
. In other words, this arrangement is disadvantageous in that the cooling air cannot be smoothly conveyed to the element mounting surfaces of the cooling fins
101
and
102
. Furthermore, the temperature of the cooling air will be increased undesirably when it arrives the rectifying elements
100
, because the cooling air is brought into contact with warmed-up members before it reaches the downstream side. Thus, the cooling efficiency is worsened significantly.
SUMMARY OF THE INVENTION
In view of the foregoing problems encountered in the prior art, the present invention has an object to provide a rectifying apparatus which is capable of remarkably improving the cooling performance by effectively introducing the cooling air to the rectifying elements and the cooling fins.
In order to accomplish the above-described and other related objects, the present invention provides a novel and excellent rectifying apparatus for an automotive AC generator. According to the present invention, the cooling fins can maintain sufficient surface areas. The cooling air is guided to both the front and rear surfaces of each cooling fin. The external air is directly introduced to the rectifying elements from both the axial direction and the radial direction. The flow speed of the cooling air is increased by partly narrowing a cross-sectional area of a ventilation passage. Thus, the heat transferring performance can be improved. The rectifying apparatus can be effectively cooled.
According to a first aspect of the present invention, the automotive AC generator has a rectifier disposed between a frame and a protecting cover. The rectifier comprises negative rectifying elements, a larger-diameter fin of negative electric potential which mounts the negative rectifying elements, positive rectifying elements, a smaller-diameter fin of positive electric potential which mounts the positive rectifying elements. Each of the rectifying elements has a lead. The larger-diameter fin is disposed adjacent to the frame and the smaller-diameter fin is disposed adjacent to the protecting cover. The larger-diameter and smaller-diameter fins are arranged parallel to each other in an axial direction with a predetermined clearance so that their leads extend in opposite directions in a space between the larger-diameter and smaller-diameter fins. A radial-inner end of the larger-diameter fin is positioned outward than a radial center of the positive rectifying elements. A radial-outer end of the smaller-diameter fin is positioned inward than a radial center of the negative rectifying elements. The protecting cover has an axial air inlet at a position corresponding to the center of the positive rectifying elements. The axial air inlet introduces external air directly to the positive rectifying elements. A radial ventilation passage is provided between the larger-diameter fin and the frame, so as to pass the center of the negative rectifying elements. An opening, which introduces external air directly, is formed on the protecting cover, or between the frame and the protecting cover, or the larger-diameter fin and the protecting cover, at a portion corresponding to the radial-outer end of the radial ventilation passage.
In other words, the rectifier (
5
) comprises negative rectifying elements (
504
), a larger-diameter fin (
503
) of negative electric potential which mounts the negative rectifying elements, positive rectifying elements (
502
), a smaller-diameter fin (
501
) of positive electric potential which mounts the positive rectifying elements, each rectifying element has a lead, and the rectifier is disposed between the frame (
3
b
) and the protecting cover (
8
). The larger-diameter fin is disposed adjacent to the frame with a predetermined axial clearance. The smaller-diameter fin is disposed adjacent to the protecting cover with a predetermined axial clearance. The larger-diameter and smaller-diameter fins are arranged parallel to each other in an axial direction with a predetermined clearance so that their leads extend in opposite directions in a space between the larger-diameter and smaller-diameter fins. A radial-inner end of the larger-diameter fin is disposed adjacent to the positive rectifying elements, and positioned radially outward than a radial center position of the positive rectifying elements. A radial-outer end of the smaller-diameter fin is disposed adjacent to the negative rectifying elements, and positioned radially inward than a radial center position of the negative rectifying elements. The protecting cover has an axial opening (
801
) which introduces external air directly to the center of the positive rectifying elements. A radial ventilation passage (
810
) is disposed between the larger-diameter fin and the frame so as to pass the center of the negative rectifying elements. And, an opening (
802
) is formed at least at one selected from the group consisting of a portion on the protecting cover, a clearance between the frame and the protecting cover, and a clearance between the larger-diameter fin and the protecting cover, for introducing external air directly to a radial-outer end of said radial ventilation passage.
The above-described arrangement brings the following functions and effects. As the smaller-diameter fin and the larger-diameter fin are offset in both the axial and radial directions, each fin can maintain a sufficient surface area.
Furthermore, as the cooling air can pass a clearance between the element-mounting surfaces of these fins, the introduced cooling air can be guided to both surfaces of each cooling fin. Thus, the fins and the rectifying elements can be adequately cooled.
Furthermore, the larger-diameter fin and the smaller-diameter fin are arranged parallel to each other in the axial direction with a predetermined clearance so that their leads extend in opposite directions in a space between the larger-diameter fin and the smaller-diameter fin. The radial-outer end of the smaller-diameter fin is disposed radially inward than the radial center position of the negative rectifying elements. The radial-inner end of the larger-diameter fin is disposed radially outward than the radial center position of the positive rectifying elements. Thus, the leads are offset to the radially inward and outward positions. Therefore, any interference between the fins and the leads can be eliminated. An axial clearance between these parallel fins can be reduced.
Accordingly, the flow speed can be increased when the cooling air passes this clearance. The cooling air hits the cooling fins at a high spe
Ihata Koichi
Ooiwa Tooru
Shiga Tsutomu
Denso Corporation
Nguyen Tran N
Pillsbury Madison & Sutro LLP
Ramirez Nestor
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