Measuring and testing – Dynamometers – Responsive to torque
Reexamination Certificate
2000-08-28
2002-08-27
Noori, Max (Department: 2855)
Measuring and testing
Dynamometers
Responsive to torque
Reexamination Certificate
active
06439065
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a torque detecting apparatus applicable to an electromotive bicycle fitted with a motor as an auxiliary drive source for example. The torque detecting apparatus of the present invention detects torque by way of transmitting drive force via a pair of rotary bodies that cause own relative position to be varied by effect of torque, to enable detection of variation of resonant frequency corresponding to variation of relative position under non-contact condition or to enable transmission of modulated signal corresponding to variation of the relative position under non-contact condition, whereby enabling the apparatus to correctly detect actual torque based on a simple structure with high precision.
2. Description of Related Art
Any of conventional electromotive bicycles has been so arranged that drive of the drive wheel can be assisted by motor-drive force in correspondence with operation of pedals performed by user within such a scope that does not affect operating safety.
Concretely, in such a conventional electromotive bicycle, ratio between pedaling force of user and drive force of the motor is designated by assist ratio. Practically, it is so arranged that the assist ratio can remain at 1:1 within such a range in which the bicycle runs at a relatively slow speed up to 15 km/h. On the other hand, it is so arranged that the assist ratio can gradually be decreased from 1:1 to 1:0 in correspondence with actual speed within a scope from 15 km/h to 25 km/h.
Because of the above arrangement, a variety of torque detecting mechanisms have been provided for conventional electromotive bicycles to detect actual pedaling force generated by users to cause the motor to be driven based on the result of the detected pedaling force.
For example,
FIG. 29
is a lateral view showing such a torque detecting mechanism and the torque detecting device
1
which causes a planetary gear
2
to transmit pedaling force to detect actual pedaling force by way of detecting torque counter-force generated on the part of a stationary gear
3
.
In specific, as shown in a partially enlarged portion with arrow A, the torque detecting device
1
has such a structure in which the stationary gear
3
having teeth being formed along external circumference is secured to a stationary portion
4
. The stationary gear
3
is secured to the stationary portion
4
by effect of a compressed spring
5
disposed between a projected piece
3
A projecting itself inside of the stationary gear
3
and another projected piece
4
A projecting itself on the part of external circumference of the stationary portion
4
.
The planetary gear
2
is rotatably retained by an annular member
6
, where the planetary gear
2
is disposed by way of engaging own teeth with the stationary gear
3
across approximately 120 degrees of angular interval on the part of external circumference of the stationary gear
3
. In the above-cited torque detecting device
1
, a crank is connected to the annular member
6
. Motor drive force is transmitted via a further transmission mechanism which is not shown in the drawing.
In the torque detecting device
1
, a drive gear
8
is disposed by way of surrounding the planetary gear
2
. Teeth formed on the part of internal circumference of the drive gear
8
are disposed via engagement with teeth of the planetary gear
8
. In the torque detecting device
1
, the drive gear
8
is rotated by drive force transmitted to the planetary gear
2
via the crank whereby transmitting drive force further to a chain
9
being engaged along external circumference of the drive gear
8
.
When drive force is transmitted in this way, by way of resisting pressing force of the compressed spring
5
after being affected by counter force of torque, as shown via arrow B, the stationary gear
3
displaces itself in correspondence with actual magnitude of torque. In response, the torque detecting device
1
causes torque to be converted into displaced amount of the stationary gear
3
, where the torque is variable in correspondence with actual pedaling force.
The torque detecting device
1
converts the displaced amount into electrical signal via a variable resistor or the like secured to the stationary portion
4
, and then, after processing electrical signal, pedaling force of user can be assisted with motor drive force solely in such a case in which user actually operates pedals with own pedaling force.
FIG. 30
is a plan view showing another example of a conventional torque detecting device
11
, in which drive force is sequentially transmitted via a coaxially supported torque converter
13
and a drive-force transmitting rotary body
12
. The torque converter
13
transmits drive force to the drive-force-transmitting rotary body
12
via an elastic member such as a spring elongating and contracting itself to subsequently cause relative position of a pair of rotary bodies
12
and
13
to be variable in correspondence with drive force.
In the torque converter
13
, it is so arranged that projecting amount of a drive-force transmitting pin
14
can be varied by the variation of the relative position of the above two rotary bodies, and yet, as is designated by reference code C, it is so arranged that a receptive plate
15
rotatably being held by a shaft can be displaced by the drive-force transmitting pin
14
. In the torque detecting device
11
, it is so arranged that the receptive plate
15
can be energized by a spring
17
secured to a stationary body
16
, and yet, by way of expanding displaced amount of the receptive plate
15
by applying a lever
18
, the displaced amount is transmitted to another torque detecting device
19
. For example, the torque detecting device
19
comprises a variable resistor whose resistance value is variable in correspondence with the displaced amount transmitted via the lever
18
. According to the above arrangement, the torque detecting device
11
transmits any variation on the rotary bodies corresponding to actual torque to the stationary members, and then, after properly processing electrical signal transmitted from the variable resistor, the torque detecting device
11
detects drive torque.
FIGS. 31A and 31B
are a plan view and a lateral view of a still further example of the conventional torque detecting device. A torque detecting device
21
incorporates a first rotary body
22
and a second rotary body
23
which are respectively disposed via coaxial structure. The first rotary body
22
is rotated by the pedaling force of user, whereas the second rotary body
23
is engaged with a chain
24
. The first rotary body
22
and the second rotary body
23
respectively transmit drive force via an elastic member such as a spring to cause relative position to be variable in correspondence with actual pedaling force.
Further, a window
22
A and another window
23
A are individually provided for the first rotary body
22
and the second rotary body
23
so that they superpose with each other. Whenever the relative positions of the first and second rotary bodies
22
and
23
are shifted, it is so arranged that dimension of aperture formed by the windows
22
A and
23
A can be varied as well.
A light-emitting unit
26
and a light-receiving unit
27
are secured to the torque detecting device
21
so as to sandwich the aperture. By causing the light-receiving unit
27
to detect measuring light emitted from the light-emitting unit
26
, the torque detecting device
21
detects such a torque-detect signal comprising a certain duty ratio being subject to variation in correspondence with actual pedaling force generated by user, as shown in FIG.
32
.
Nevertheless, in such a conventional structure using a planetary gear as was described earlier by referring to
FIG. 29
, it is quite essential that structure in the periphery of the stationary gear be strong enough to withstand pedaling force and drive force, whereby entailing complex structure, and yet, increasing weight. Further, it also entails problem in that o
Eguchi Yasuhito
Hayashi Toshiro
Ooshima Syunji
Sato Naomasa
Tanina Shoji
Frommer William S.
Frommer & Lawrence & Haug LLP
Noori Max
Ryan Matthew K.
Sony Corporation
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