Method for mounting a plurality of brushes

A position-detecting device is formed by mounting a plate onto a base body. The plate carries a plurality of slide terminals adapted to slide on contact paths of a cooperating member. Sections of the plate which carry respective groups of the slide terminals are interconnected by narrow portions of the plate. After the plate has been mounted on the body so as to situate the slide terminals in predetermined locations, the narrow portions are served to seperate the plate sections into the separate brushes, each having a respective group of slide terminals.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an electric actuator, i.e., an actuator to 
be operated by an electric motor, and more particularly to a 
position-detecting apparatus for detecting a rotated position of the 
output shaft of an actuator for opening and closing a damper of a vehicle 
air conditioner so as to make it possible to stop the motor at a 
predetermined position by pressing an appropriate switch so as to stop the 
damper at a selected position. The present invention also relates to a 
method for fixing brushes to the position-detecting apparatuses provided 
with various kinds of electric actuators. 
2. Description of Related Art 
When a plurality of brushes are provided, for example, on a movable portion 
of a position-detecting apparatus, brushes are individually heat-caulked 
onto the flat portion of a gear mounted on an output shaft. This method is 
described hereinbelow with reference to FIGS. 16 through 24. 
As shown in FIGS. 16 through 19, a position-detecting apparatus (S) 
comprises a gear 30 and brushes 40 (40a and 40b). The gear 30 comprises an 
output shaft 32 and a disk 33 to which brushes 40 are fixed. The output 
shaft 32 and the disk 33 are integrated with each other through a boss 31. 
As shown in FIG. 18, the outer circumferential face 33a of the disk 33 
contains gear teeth teeth-shaped convexed, namely, gear teeth-shaped. 
Predetermined number of openings 34 are formed at predetermined positions 
of the disk 33. Supporting members 41 to be described later are inserted 
under pressure, or pressed into the opening 34 having a step 34a, 
respectively. The brushes 40a and 40b as shown in FIGS. 20 through 23 are 
fixed to the top surface of the disk 33 of the gear 30 by, for example, a 
heat-caulking. 
The method for fixing the brushes 40 to the disk 33 is described 
hereinbelow taking the brush shaped as shown in FIG. 20 as an example. The 
supporting members 41 as shown in FIG. 22 are mounted on the brush 40a, 
and the supporting members 41 are fixed under pressure to the openings 34 
formed at predetermined positions in the disk 33. The supporting members 
41 are mounted on the flat portion 42 and the bent portion 43 of the brush 
40a. The supporting member 41 comprises a portion 41a to be inserted under 
pressure into the opening 34 and a claw 41b which engages with a step 34a 
of the opening 34. Therefore, the supporting member 41 is prevented from 
being disengaged from the opening 34. 
However, the position-detecting apparatus constructed by the 
above-described conventional method is required to be accurate in 
dimensions of respective brushes, in arranging the respective brushes at 
predetermined positions, and in the positions and dimensions of the 
openings formed on the disk to be used as a base body. 
Further, when brushes are individually fixed to the flat portion of the 
disk of the gear by a heat-caulking, dimensions of projections formed on 
the supporting member to be heat-caulked and the dimensions of the brushes 
may differ from each other. As a result, the brushes are fixed to the flat 
portion of the disk of the gear at different angles, which causes the 
rotated position-detecting apparatus to detect the rotated position of the 
output shaft of the actuator with a low accuracy. 
In addition, the fixing of the brushes to the disc one by one leads to the 
increase of the number of manufacturing processes. 
As shown in FIG. 24, in the above-described position-detecting apparatus 
for detecting the position of the output shaft of the actuator for opening 
and closing an exhaust change-over damper, switching patterns 5a, 5b, 5c, 
5d, and 5e connected to a switch for ventilation 4a, a switch for B/L 4b, 
a switch for heating 4c, a switch for heat/defrosting 4d, and a switch for 
defrosting 4e of an exhaust selection switch 4, respectively are 
concentrically formed on a printed body. A pair of brushes is mounted on 
one of both faces of a gear mounted on an output shaft in symmetrical 
relationship with respect to the output shaft. The slide terminals of the 
brushes slide on the switching patterns 5a through 5e, respectively. 
In the above-described position-detecting apparatus, the position at which 
the actuator stops is affected in a great extent by the positions of the 
edges of the respective switching patterns, namely, by a manufacturing 
accuracy thereof. For example, if the edge position of a respective 
switching pattern is different from a predetermined value by "l", the 
angle error .theta. of the pattern edge, namely, the angle error which 
affects the stop angle of the actuator is expressed as follows: 
EQU .theta.=tan.sup.-1 l/R 
where R is the radius of the pattern. That is, as the radius R of the 
pattern becomes small, the angle error of the pattern edge increases. 
Specifically, in FIG. 24, the usage of the pattern 5a allows the actuator 
to stop with a higher accuracy than the usage of the pattern 5b. Thus, 
when the pattern 5e nearest the center of a base body is operated, the 
actuator stops with the lowest accuracy. This is a great disadvantage of 
the conventional rotated position-detecting apparatus. 
SUMMARY OF THE INVENTION 
The present invention has been made with a view to substantially solving 
the above-described disadvantages. 
It is an object of the present invention to provide a position-detecting 
apparatus in which a brush-formed plate having a plurality of brushes 
integrated with each other through narrow portions is fixed to a base 
body, and thereafter, the narrow portions are cut off. 
It is another object of the present invention to provide a method for 
fixing brushes of a position-detecting apparatus of an electric actuator, 
wherein openings formed on a base body coincide with the positions of 
narrow portions formed on a brush-formed plate. 
It is a further object of the present invention to provide a method for 
fixing brushes of a position-detecting apparatus of an electric actuator, 
wherein projections formed on the brush-fixing face of the base body are 
inserted through openings formed on the brush-mounted plate, and 
thereafter, the projections are heat-caulked. 
It is a still further object of the present invention to provide a method 
for fixing brushes of a position-detecting apparatus of an electric 
actuator, wherein a base body whose outer circumferential face contains 
gear teeth is used. 
it is a still another object of the present invention to provide a method 
for fixing brushes of a position-detecting apparatus of an electric 
actuator, wherein a base body is integrally formed of a synthetic resin. 
According to the present invention, the use of the brush-formed plate in 
which a plurality of brushes are integrated with each other eliminates the 
need for considering the accuracy of, for example, the dimensions of 
respective brushes. Further, since the brush-mounted plate fixed to the 
base body is divided by cutting off the narrow portions at predetermined 
positions, it is unnecessary to consider the accuracy of, for example, the 
positions and dimensions of respective openings through which the edges of 
the brushes are inserted. Therefore, the position-detecting apparatus can 
be easily manufactured. In addition, since the positions of the openings 
formed on the base body correspond to the positions at which narrow 
portions are formed on the brush-formed plate, resulting chips can be 
easily removed through the openings. Furthermore, since only the 
brush-formed plate is required to be fixed to the base body in 
constructing the position-detecting apparatus, an operation can be 
efficiently performed, the number of assembling processes can be reduced, 
and an automatic assembling is easy. 
Also, there is provided according to the present invention, a 
position-detecting apparatus in which the distance between concentrically 
arranged edges of respective switching patterns and the center of a base 
body are the same as the distance between the edge of the switching 
pattern arranged remote from the center of the base body and the center 
thereof so as to easily detect a position of the output shaft of an 
actuator. 
In order to achieve the object, an actuator according to the present 
invention comprising a member to be driven connected to an output shaft to 
be rotated by a motor through a sped reduction mechanism, a pair of 
brushes mounted on a gear fixed to the output shaft in a symmetrical 
relationship with respect to the output shaft, a plurality of comb-shaped 
slide terminals provided with each of the brushes, a base body so disposed 
that the respective slide terminals of a pair of the brushes slide on the 
switching patterns, a motor which is stopped by cutting off electric 
current so as to stop the member to be driven at a predetermined position 
when the slide terminals of the brushes reach the switching patterns, 
wherein except the switching pattern of common terminals disposed nearest 
the center of the base body, all of the concentrically disposed switching 
patterns are so shaped that the motor-stopping edges of the switching 
patterns are brought into contact with a slide terminal disposed on the 
most outer circumference so as to stop the motor when the slide terminals 
of the brushes are brought out of contact with the edge of the switching 
pattern disposed on the most external circumference. 
The above-described actuator is used to open or close the dampers of an air 
conditioner for use in a vehicle. According to this arrangement, the 
switching patterns are connected to switches for selecting 
damper-opening/closing positions, electric current is cut off to stop the 
motor when the slide terminals of the brushes reach the edge of a 
switching pattern connected to a switch which has been turned on, and the 
damper which is opened or closed by the motor through the output shaft is 
stopped at a predetermined position selected by the switch. Accordingly, 
the edge of each of the switching patterns is disposed at the most 
external circumference and the amount of an angle error of the edge of the 
switching pattern is small, and the damper can be stopped with a high 
accuracy, which meets the demand for a damper to stop at a very high 
accuracy, namely, at a predetermined position.

DETAILED DESCRIPTION OF THE INVENTION 
An embodiment of the present invention is described with reference to FIGS. 
1 through 15. 
An electric actuator according to the present invention, namely, an 
electric actuator for opening and closing an air conditioner for use in a 
vehicle detects a rotational or angular position of the output shaft of a 
position-detecting apparatus and stops a motor at a predetermined position 
selected by a switch so as to stop a damper at a selected position. In 
this kind of air condition for use in a vehicle, the following operations 
are performed. Dampers shown in FIG. 1 include an air refreshing damper 
(R/F) 1, air-mixing damper (A/M) 2, an exhaust change-over damper (MODE) 
3. These dampers are opened or closed by an actuator. The actuator 
transmits the rotation of a motor to an output shaft through a gear 
reduction mechanism. The dampers 1, 2, and 3 are opened or closed 
according to the amount of rotation of the output shaft. A brush 
constituting a position-detecting mechanism is mounted on a gear affixed 
to the output shaft. A base body on which switching patterns are mounted 
is arranged at a position at which the switching patterns and brushes 
contact each other. A selection switch is connected to a switching 
pattern. The brushes slide on the switching patterns in unison with the 
rotation of the output shaft. When a brush reaches the edge of a switching 
pattern connected to the selection switch which is ON, electric current is 
cut off. As a result, the motor is stopped and the dampers are stopped at 
predetermined positions by operating the selection switch. 
The relationship between the brush and the switching pattern of the rotated 
position-detecting apparatus for detecting the output shaft of an actuator 
for opening and closing an exhaust change-over damper is as follows: In 
the case of an exhaust change-over damper, as shown in FIG. 14, switching 
patterns 11 through 15 connected to a switch for ventilation 4a, a switch 
for B/L 4b, a switch for heating 4c, a switch for heat/defrosting 4d, and 
a switch for defrosting 4e of an exhaust selection switch 4 are formed 
concentrically on a printed body. As shown in FIG. 2, a pair of brushes 8 
and 9 is symmetrically mounted on one surface of a base body 7 fixed to an 
output shaft 6. Slide terminals 8a through 8e and 9a through 9e of the 
brushes slide on the switching patterns 11 through 15 respectively. 
Referring to FIG. 3, the brush-formed plate 10 on which brushes 8 and 9 are 
integrated with each other is fixed to a base body 7 constituting the 
position-detecting apparatus. Thereafter, narrow portions 10a of the 
brush-formed plate 10 are cut off to form a plurality of mutually 
insulated brushes 8 and 9. 
That is, the position-detecting apparatus is composed of the base body 7 
and a plurality of brushes 8 and 9 fixed to the base body 7 by weldments 
10b. Specifically, the narrow portions 10a are cut off. 
The use of the integrated brushes 8 and 9 which form the brush-formed plate 
10 eliminates the need for considering the accuracies of dimensions and 
positions of respective brushes when they are manufactured. The 
brush-formed plates 10 mounted on openings formed on the base body 7 are 
cut off at predetermined positions. Therefore, it is unnecessary to 
consider the accuracy of the dimensions or the positions of the brushes. 
Thus, the brushes can be more easily fixed to the brush-formed plate 10 of 
the position-detecting apparatus. 
Another embodiment of the present invention is described with reference to 
FIGS. 6 through 11. As shown in FIG. 6, four groups of brushes are used in 
this embodiment. The angle formed between three angularly spaced brushes 
is 120.degree. (brushes 102a and 102b are parallel with each other.) The 
portions of the brushes which contact with the switching patterns perform 
their functions provided that there are more than two, for example, three 
or more. It is permitted that the angles to be made by the brushes 102a 
(102b) and 102c, 102c and 102d, and 102d and 102a (102b) are different. 
The position-detecting apparatus (S) of this embodiment comprises a gear 
101 as shown in FIGS. 6 and 7 which is used as a base body and mounted on 
the movable portion of the position-detecting apparatus (S) and brushes 
102a through 102d mounted on the gear 101. 
As shown in FIGS. 8 and 9, the gear 101 which functions as the base body 
comprises a cylinder shaft 120 which is made of a thermoplastic synthetic 
resin and acts as an output shaft and a disk 130 which is also made of the 
thermoplastic synthetic resin and fixes the brushes 102 thereto. The 
cylinder 120 and the disk 130 are integrally formed with each other 
through a boss 110. The disk 130 is rotatable because it has gear teeth 
formed on the outer circumferential face thereof which engage with a gear 
and a worm (not shown). Thus, brushes 102 rotate slidably on the switching 
patterns of the rotated position-detecting apparatus (S). 
Openings 141 through 149 and projections 150 are formed at predetermined 
positions of the disk 130. 
The positions of the openings 141 through 149 formed on the disk 130 
correspond to the positions of a brush-formed plate 200 to be cut off. The 
number of the openings formed thereon also corresponds to that of the 
brush-formed plate 200 to be cut off. The brush-formed plate 200 is 
described later. Since four brushes are formed by cutting off narrow 
portions 103 in this embodiment, the openings 141 through 149 are formed 
at predetermined positions as shown by reference numerals 141 through 143, 
144 through 146, and 147 through 149. The areas of the openings shown by 
reference numerals 142 and 149 are greater than the other openings 140 
because the brush-formed plate 200 is cut off at positions in 
consideration of the dimensions of the openings 142 and 149, which is 
described later. 
Projections 150 formed on the disk 130 are inserted through openings 250 
formed on the brush-formed plate 200 which is to be described later. 
Therefore, the number and positions of the projections 150 and the 
openings 250 correspond with each other. In this embodiment, the number of 
the projections 150 and the openings is 10, respectively and the diameters 
of the openings 250 are a little greater than those of the projections 
150. 
Referring to FIGS. 10 and 11, the brush-formed plate 200 is a conductive 
metal plate having a spring-like elasticity. The brush-formed plate 200 is 
formed as one piece. Specifically, an opening 201 for inserting the 
cylinder 120 therethrough is formed in the center of the brush-formed 
plate 200 by a press, and predetermined number of portions which contact 
with switching patterns are formed thereon. That is, when the brush-formed 
plate 200 is formed, the peripheries of the opening 201 and the contact 
portions 210 through 213 are punched. In this embodiment, the angles 
between the contact portions 210 (211) and 212, 212 and 213, and 213 and 
210 (211) are 120.degree., respectively. As shown in FIG. 11, the base 
portions of the contact portions 210 through 213 are integral with fixed 
portions 220 through 223, respectively. The contact portions 210 through 
213 extend upward from the brush formed plate 200. When the brush-formed 
plate 200 is formed by the press, the openings 250 through which the 
projections 150 of the disk 130 are to be inserted are punched through the 
fixed portions 220 through 223. The number of the openings 250 is the same 
as that of the projections 150. 
As described above, the opening 201 of the brush-formed plate 200 fits over 
the boss 110, and the projections 150 are inserted through the openings 
250 of the brush-formed plate 200. Accordingly, the brushes can be fixed 
to the gear 101 at predetermined positions thereof. 
As shown in FIG. 10, cut-outs 261, 262, and 263 are formed on the 
brush-formed plate 200 so that the brushes comprising the contact portions 
210, 211, 212, and 213 and fixed-contact portion 220, 221, 222, and 223 
integrated with the contact portions 210 through 213, respectively are 
easily cut out from each other. In this embodiment, the portions 261, 262, 
263 correspond to the narrow portions 103 (refer to oblique lines in FIG. 
6) connecting the respective brushes 102a, 102b, 102c, and 102d. 
The method for assembling the rotated position-detecting apparatus (S) by 
fixing the brush-formed plate 102 having the above-described construction 
to the gear 101 so as to form the brushes 102a, 102b, 102c, and 102d is 
described hereinbelow. 
The brush-formed plate 200 is mounted on the gear 101 in the following 
manner: The output shaft 120 is inserted into the opening 201 of the 
brush-formed plate 200. The output shaft 120 is supported by the boss 110 
formed in the center of the gear 101, and the projections 150 formed on 
the gear 101 are inserted into the openings 250 of the brush-formed plate 
200. In this embodiment, since the boss 110 and the opening 201 of the 
brush-formed plate 200 are formed in the center of the gear 101 and the 
brush-formed plate 200, respectively, the brush-formed plate 200 and the 
gear 101 are firmly fixed to each other. The projections 150 of the gear 
101 are caulked by heating or ultrasonic wave so that the gear 101 and the 
brush-formed plate 200 are firmly fixed to each other. As shown in FIGS. 
6, 8, and 10, the respective fixed portions integral with the contact 
portions are fixed to the gear 101 at two positions or more in this 
embodiment when the integrated brushes 200 are separated from each other 
so that the brushes 200 are prevented from being shaken and rotated 
relative to the gear 101 acting as the base body. This method of fixing 
the brush-formed plate 200 to the gear 101 allows gaps intentionally 
provided between the projections 150 of the gear 101 and the openings 250 
of the brush-formed plate 200 to be filled with a melted synthetic resin. 
After the brush-formed plate 200 is fixed to the gear 101, the narrow 
portions 103 (refer to the oblique lines in FIG. 6) are cut off by, for 
example, a laser beam to form insulated sets of brushes comprising the 
contact portions 210, 211, 212, and 213 and the fixed portions 220, 221, 
222, and 223, respectively. Since the positions of those narrow portions 
103 of the brush-mounted plate 200 coincide with the positions of the 
openings 141 through 149 formed on the disk 130, resulting chips produced 
when the narrow portions 103 are cut off are removed through the openings 
141 through 149, which prevents the deformation of the resin of the disk 
130. 
In this embodiment, the brushes are fixed to the gear 101 by inserting the 
projections 150 of the disk 130 through the openings 250 of the 
brush-formed plate 200. In addition, projections or concaves may be formed 
on the boss 110 and concave cut-outs in which the projections are fitted 
or gables which are fitted in the concaves may be formed on the 
brush-formed plate 200. 
Another embodiment is described with reference to FIGS. 12 and 13. In this 
embodiment, brushes are mounted on a base body which is a fixed portion of 
a rotated position-detecting apparatus. 
As shown in FIGS. 12 and 13, a base body 104 and a connector 105 made of 
resins are integrated with each other. The position-detecting apparatus is 
formed by connecting the connection terminals 105a of the connectors 105 
and the base portions 107 of the brushes 106 (106a, 106b, 106c, and 106d). 
As shown in FIG. 13, a brush-formed plate 600 is divided into four brushes 
106a, 106b, 106c, and 106d having contact portions 610, 611, 612, and 613, 
respectively. Narrow portions 103 connect the brushes 106a, 106b, 106c, 
and 106d with each other. 
As shown in FIG. 12, the positions of six openings 441 through 446 formed 
on the base body 104 coincide with the positions of narrow portions 103 
when the brush-formed plate 600 is fixed to the base body 104. The 
procedure of fixing the brushes 106a, 106b, 106c, and 106d to the base 
body 104 having the above-described construction is the same as that of 
the embodiment described hereinabove. 
As apparent from the foregoing description, since the brush-formed plate 
having a plurality of brushes integrated with each other is used, it is 
unnecessary to consider accuracy of the dimensions of the respective 
brushes when they are manufactured. Further, since the positions of the 
narrow portions of the brush-formed plate coincide with the positions of 
the openings of the gear so as to divide the brush-formed plate into 
predetermined number of brushes, it is unnecessary to consider the 
accuracy of the dimensions of the openings into which the brushes are 
inserted, i.e., the brushes are easily fixed to the base body of the 
rotated position-detecting apparatus. 
Further, since the brush-formed plate fixed to the base body is divided by 
cutting off the narrow portions at predetermined positions, it is 
unnecessary to consider the accuracy of, for example, the positions and 
dimensions of respective openings through which the edges of the brushes 
are inserted, which is different from the conventional method. Therefore, 
the rotated position-detecting apparatus can be easily manufactured. In 
addition, since the positions of the openings forms on the base body 
correspond to the positions of the narrow portions formed on the 
brush-formed plate, resulting chips can be easily removed through the 
openings. Furthermore, since only the brush-formed plate is required to be 
fixed to the base body in constructing the rotated position-detecting 
apparatus, an operation can be efficiently performed, the number of 
assembling processes can be reduced, and an automatic assembling is easy. 
As shown in FIG. 5, an actuator according to the present invention 
comprises a member to be driven connected to an output shaft to be rotated 
by a motor through a speed reduction mechanism, and a pair of brushes 8 
and 9 mounted on a gear 7 fixed to the output shaft 6 in a symmetrical 
relationship with respect to the output shaft. Each brush comprises a 
plurality of comb-shaped slide terminals arranged to the slide on the 
switching patterns 11 and 12. Also provided is a motor which is stopped by 
cutting off electric current so as to stop the member to be driven at a 
predetermined position when the slide terminals of the brushes reach the 
switching patterns. Except for the switching pattern of the common 
terminals disposed nearest the center of the base body, all of the 
concentrically disposed switching patterns are so shaped that the 
motor-stopping edges of the switching patterns are brought into contact 
with a slide terminal disposed on the most outer circumference so as to 
stop the motor when the slide terminals of the brushes are brought out of 
contact with the edge of the switching pattern disposed on the most 
external circumference. 
The above-described actuator is used to open or close the dampers of an air 
conditioner for use in a vehicle. According to this arrangement, the 
switching patterns are connected to switches for selecting 
damper-opening/closing positions. Electric current is cut off to stop the 
motor when the slide terminals of the brushes reach the edge of a 
switching pattern connected to a switch which has been turned on, and the 
damper which is opened or closed by the motor through the output shaft is 
stopped at a predetermined position selected by the switch. Accordingly, 
the edge of each of the switching patterns is disposed at the most 
external circumference and the amount of an angle error of the edge of the 
switching pattern is small, and the damper can be stopped with a high 
accuracy, which meets the demand for a damper to stop with a very high 
accuracy, namely, at a predetermined position. 
Referring to FIG. 14, still another embodiment is described. Circular 
switching patterns 11, 12, 13, 14, and 15 are concentrically formed on a 
printed board 10 about a center "O" and the end portions of the respective 
switching patterns 11 through 15 project radially outwardly so that the 
edges 11a (11b), 12a, 13a, 14a, and 15a thereof are brought into contact 
with the slide terminal 8a of the brush 8 and the slide terminal 9a of the 
brush 9 relatively remotely from the output shaft 6 shown in FIG. 2. As 
shown in FIG. 14, the switching pattern 11 is connected to a switch for 
heating 4c of an exhaust change-over switch 4, the switching pattern 12 is 
connected to a switch for heating/defrosting 4d thereof, the switching 
pattern 13 is connected to a switch for B/L 4b thereof, the switching 
pattern 14 is connected to a switch for ventilation 4a thereof, and the 
switching pattern 15 is connected to a switch for defrosting 4e thereof. 
Switching patterns 16A and 16B acting as common terminals are formed 
internally from the switching patterns 14 and 15 nearest the center "O". 
The halfcircular common terminals 16A and 16B are symmetrical with each 
other with respect to a line X. Connection portion 16A-1 projects from one 
of the ends of the common terminal 16A and the connection portion 16B-1 
project from one of the ends of the common terminal 16B. Both connection 
portions 16A-1 and 16B-1 are connected to a motor 20. 
The switching pattern 11 connected to the switch for heating 4c is disposed 
in the left from a line "Y" passing through the center "O" and 
perpendicular to the line "X", and a slight gap is provided between the 
edge 11a of the switching pattern 11 and the line "Y", and a slight gap is 
also provided between the edge 11b thereof and the line "Y". When a pair 
of the brushes 8 and 9 shown in FIG. 2 is on the line "Y", none of the 
slide terminals 8a through 8e and the slide terminals 9a through 9e 
contact with the edges 11a and 11b of the switching pattern 11. One of the 
end portion of the switching pattern 12 is in the right from the line "Y" 
and the outer line of a cam 12b is disposed on the same circumference as 
the outer line of the edge 11b. The edge 12a projecting from the cam 12b 
acts as a stopping edge. Similarly, one of the end portion of the 
switching pattern 13a is in the right from the line "Y", and the outer 
line of a cam 13b is on the same circumference as the outer line of the 
edge 11a of the switching pattern 11. The edge 13a projecting from the cam 
13b acts as a stopping edge. The switching patterns 14 and 15 formed 
internally from the switching patterns 12 and 13 are symmetrical with each 
other with respect to the line "X", and cams 14b and 15b are in the right 
from the line "Y", and the outer lines of cams 14b and 15b are on the same 
circumference as the edge 11a (11b). The edges 14a and 15a projecting from 
the cams 14b and 15b, respectively act as stopping edges. 
Thus, the outer lines of the respective edges 11a (11b), 12a, 13a, 14a, and 
15a of the switching patterns 11 through 15 are on the most outer 
circumference. 
The brush 8 which slides on the switching patterns contact with none of the 
switching patterns when the brush 8 is disposed between the edge 14a of 
the switching pattern 14 and the line "X". Accordingly, electric current 
does not flow through the rotated position-detecting apparatus. As a 
result, the rotation of the brush 8 is stopped. Similarly, when the brush 
9 is disposed between the edge 15a of the switching pattern 15 and the 
line "X", no electric current flows through the rotated position-detecting 
apparatus. As a result, the rotation of the brush 9 is stopped, i.e., the 
brushes do not rotate when they are in the range "A" shown in FIG. 14. The 
slide terminal 8a disposed at the most outer circumference of the brush 8 
slides on the edge 11a and in the vicinity of the edge 11a of the 
switching pattern 11, the cams 13b (edge 13a) of the switching pattern 13 
and 14b (edge 14a) of the switching pattern 14. The slide terminal 9a 
disposed at the most outer circumference of the brush 9 slides on the edge 
11b and in the vicinity of the edge 11b) of the switching pattern 11, the 
cam 12b (edge 12a) of the switching pattern 12 and the cam 15b (edge 15a) 
of the cam 15. The slide terminal 8b slides on the switching pattern 11. 
The slide terminal 8c slides on the switching pattern 13. The slide 
terminal 8d slides on the switching pattern 14. The slide terminal 9b 
slides on the switching pattern 11. The slide terminal 9c slides on the 
switching pattern 12. The slide terminal 9d slides on the switching 
pattern 15. The slide terminal 8e disposed nearest the output shaft 6 
slides on the common terminal 16A. The slide terminal 9e nearest the 
output shaft 6 slides on the common terminal 16B. 
The circuit connecting the common terminal 16A and the motor 20 and the 
circuit connecting the common terminal 16B and the motor 20 are provided 
with a resistor R.sub.1 and a capacitor C.sub.1, and a resistor R.sub.2 
and a capacitor C.sub.2, respectively so as to prevent a chattering. The 
circuits are also provided with resistors R.sub.3 and R.sub.4, 
respectively so that resistances are generated during a discharge. 
The operation of the position-detecting apparatus is described hereinbelow. 
When the switch for defrosting 4e of the exhaust change-over switch 4 is 
turned on, some of the slide terminals 9a through 9d of the brush 9 slide 
on the switching pattern 15. Accordingly, electric current flows through 
the motor 20, so that the motor 20 is rotated. At this time, only the 
slide terminal 9d contacts with the switching pattern 15 before the brush 
9 reaches the cam 15b of the switching pattern 15. When the brush 9 has 
reached the cam 15b and the edge 15a, the slide terminals 9a through 9d 
contact with the cam 15b. When the brush 9 reaches the edge 15a, only the 
slide terminal 9a contacts with the edge 15a. Thereafter, the slide 
terminal 9a is brought out of contact with the edge 15a. As a result, the 
motor 20 is stopped because electric current does not flow therethrough 
and at the same time, the output shaft 6 to be driven by the motor 20 is 
stopped, which causes the brushes 8 and 9 to stop. When the other switches 
are turned on, operations similar to the above occur, i.e., when the slide 
terminals 8a of the brush 8 or the slide terminal 9a of the brush 9 
remotest from the output shaft 6 is brought out of contact with the edges 
of the switching patterns 11 through 15, electric current does not flow 
through the motor 20. As a result, the motor 20 is stopped, which causes 
the damper (not shown) to stop at a predetermined position in association 
with the stop of the motor 20. 
As described above, since the stopping edges of the switching patterns 11 
through 15 are so shaped that they contact with the slide terminal 
disposed remotely from the center, the position at which the output shaft 
of the actuator has stopped can be reliably detected. Accordingly, the 
motor can be stopped with a high accuracy. 
The configurations of the switching patterns 11 through 15 are not limited 
to those described in the embodiment as shown in FIG. 14. As shown in FIG. 
15, in order to prevent switching patterns from overlapping with each 
other, a switching pattern 21 provided on the back surface of the printed 
board may be connected to a switching pattern 12" provided on the front 
surface thereof. The use of the switching pattern 21 may be replaced with 
a jumper line such as a lead wire. It is necessary, however, that the 
stopping edge of each of the switching patterns is disposed at a position 
at which the stopping edge contacts with a slide terminal disposed on the 
most outer circumference. 
As apparent from the foregoing description, in the rotated 
position-detecting apparatus according to the present invention, since the 
stopping edge of each of the concentrically arranged switching patterns 
which contacts with a brush is disposed on the most outer circumference of 
the base body, the position at which the output shaft of the actuator has 
stopped can be reliably detected. Accordingly, the motor can be stopped 
with a high accuracy and the rotated position-detecting apparatus can be 
preferably used for the damper-opening/closing apparatus of an air 
conditioner for use in a vehicle.