JP2009248668A - Driving unit for electrically power assisted bicycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving unit for an electrically power assisted bicycle, easily attacheable to a conventional bicycle without modification. <P>SOLUTION: The driving unit for the electrically power assisted bicycle is attached to a frame F of the bicycle afterwards. The driving unit includes: a main gear 4 provided with a crank stopping part 4a for rotating a crank A of the bicycle Y; a gear transmission mechanism 5 for connecting the main gear 4 and a battery-operated motor 6 with a gear-reduction mechanism; and a one-way clutch 51 for allowing a driving force of the motor 6 with the gear-reduction mechanism to escape when a difference between a pedal rotating speed and a rotating speed of the motor with the gear-reduction mechanism occurs in the gear of the gear transmission mechanism 5. The driving unit also includes a control circuit 8 for executing on/off control of a switching mechanism 7 for engaging and disengaging of the gear transmission mechanism 5 and the main gear 4, based on a vehicle speed detected by a vehicle speed detecting mechanism 9 or a braking operation, and for making on/off control of the motor 6 with the gear-reduction mechanism based on the vehicle speed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power unit for an electrically assisted bicycle for making a commercially available bicycle an electrically assisted bicycle.

  2. Description of the Related Art Conventionally, various types of attaching an auxiliary power mechanism for electric assist to a bicycle are known (for example, see Patent Document 1).

However, these bicycles need to be newly incorporated with a motor and a gear that meshes with the output shaft of the motor. Therefore, it is necessary to redesign and make a major modification. There has been a demand for the development of an electrically assisted bicycle that can be retrofitted and provided at low cost.
JP 2007-91159 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a power unit for an electrically assisted bicycle in which the power unit can be easily attached without modifying a conventional bicycle.

  The present invention is a power unit for an electrically assisted bicycle that can be retrofitted to a bicycle frame, and includes a main gear provided with a crank locking portion for rotating a bicycle crank, and the main gear and a battery-type motor with a speed reducer. A gear transmission mechanism that is linked, and a one-way clutch that releases the driving force of the motor with a speed reducer when a difference occurs between the rotational speed of the pedal and the speed of the motor with the speed reducer. For a power-assisted bicycle provided with a switching mechanism for engaging / disengaging the gear transmission mechanism with the main gear based on the vehicle speed or brake operation detected by the vehicle and a control circuit for on / off controlling the motor with a speed reducer based on the vehicle speed The power unit is the invention of claim 1.

  The present invention provides a crank locking portion for rotating a crank of a bicycle by providing a crank locking portion for rotating a crank of a bicycle on a main gear to which a driving force of a battery-type motor with a reduction gear is transmitted via a gear transmission mechanism. Since it is only necessary to lock the bicycle and attach the power unit to the bicycle, there is no need to modify the bicycle drive mechanism in order to link the bicycle drive mechanism and gear transmission mechanism, and the bicycle can be provided at low cost. This bicycle can be made an electric assist bicycle easily and in a short time.

Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings.
1 is a power unit for an electrically assisted bicycle that can be retrofitted to the frame F of the bicycle, 2 is a secondary battery with a power switch for supplying power to the power unit 1, and the secondary battery 2 may be a nickel hydride battery or A lithium ion battery is used. The secondary battery 2 is detachably attached to the frame F of the bicycle, and can be removed and charged indoors when charging. Reference numeral 1a denotes a mounting bracket for mounting the power unit 1 to the frame F of the bicycle.

  Reference numeral 3 denotes a power unit case that is substantially J-shaped and separable into two parts. On the base side of the power unit case 3, there is a main gear 4, a gear transmission mechanism 5, and a motor 6 with a reduction gear that can rotate forward and backward. A switching mechanism 7 for turning on and off the gear transmission mechanism 5 with respect to the main gear 4, a control circuit 8 for controlling the switching mechanism 7 and the motor 6 with a speed reducer, and a vehicle speed detecting mechanism 9 for detecting the vehicle speed. It has been. In addition, a pedal hole 3a is formed through the center of the circular portion of the power unit case 3 for allowing the pedal P to be inserted when the power unit 1 is mounted on a bicycle.

  The main gear 4 is a ring-shaped spur gear, and a crank locking portion 4a is provided on the side surface of the spur gear. The crank locking portion 4a is composed of a pair of two pins that are implanted with a gap substantially equal to the thickness of the crank A. Further, the main gear 4 is rotatably held by supporting the outer peripheral surface of the annular portion 40 formed on the back side surface by six bearings 41 that are fixed to the power unit case 3.

  Reference numeral 42 denotes an attachment member for attaching the main gear 4 and the power unit case 3 to the bottom bracket shell S. The attachment member 42 rotatably holds the main gear 4 on the power unit case 3 on the base side, and at the same time Even if a slight deviation occurs between the central axis of the main gear 4 and the central axis of the crankshaft, the structure can absorb the deviation and rotate smoothly.

  As shown in FIGS. 4, 5, and 7, the mounting member 42 sandwiches two substantially half-moon-shaped members 42 a on which outer casings that hold the inner peripheral edge of the main gear 4 are formed, and the cylindrical portion of the bottom bracket shell S. A substantially U-shaped member 42b for locking the inner peripheral edge to the flange of the bottom bracket B, and a substantially half-moon shaped fixture 42c for fixing the screw by sandwiching the power unit case 3 between the substantially half-moon shaped member 42a and the substantially U-shaped member 42b. Therefore, a slight clearance can be provided between the outer peripheral edge of the substantially half-moon-shaped member 42a and the inner peripheral edge of the main gear 4. Therefore, even if an attachment error occurs when the power unit 1 is attached to the bicycle. The main gear 4 can be smoothly rotated.

  Reference numeral 42d denotes four cylindrical protrusions formed on one substantially half-moon-shaped member 42a, and each of the cylindrical protrusions 42d fits into each cylindrical hole 42e formed through the other substantially half-moon-shaped member 42a. Since both are integrated, the cylindrical portion of the bottom bracket shell S is firmly clamped and fixed by the substantially meniscus member 42a.

  Furthermore, since the U-shaped inner diameter of the substantially U-shaped member 42b is equal to the outer diameter of the cylindrical portion of the bottom bracket shell S, if the cylindrical portion of the bottom bracket shell S is sandwiched by the substantially U-shaped member 42b, the substantially U-shaped member 42b is attached with the bottom bracket shell S and the central axis aligned. Reference numeral 42f denotes a notch formed in one substantially U-shaped member 42b in order to prevent interference with the bottom bracket shell S.

  The gear transmission mechanism 5 connects the main gear 4 and the motor 6 with a speed reducer, and the gear transmission mechanism 5 includes a first bevel gear 50 attached to the output shaft of the motor 6 with a speed reducer, It comprises a second bevel gear 52 attached to a one-way clutch 51 that meshes with the first bevel gear 50, and a swingable sub gear mechanism 53 that meshes and disengages with the main gear 4.

  The sub-gear mechanism 53 includes a small spur gear 54, a large spur gear 55 meshing with the small spur gear 54, and a bracket 56 that fixes the small spur gear 54 and the large spur gear 55. The shaft is pivoted about a pivot, and the spur gear 55 and the main gear 4 are brought into and out of contact with each other to engage and disengage with the main gear 4.

  Further, since the rotational force of the second bevel gear 52 is transmitted to the small spur gear 54 via the one-way clutch 51, the second bevel gear is transmitted from the main gear 4 via the small spur gear 54 of the sub gear mechanism 53. When there is a difference between the rotational speed transmitted to 52 and the rotational speed transmitted from the motor 6 with speed reducer to the first bevel gear 50, the driving force of the motor 6 with speed reducer is transmitted to the pedal P and pedaling is performed. It prevents the unnatural driving force from being transmitted to the occupant's legs. This is because when the pedaling operation becomes slower than the motor 6 with a speed reducer during traveling or when the pedaling operation is stopped, the second bevel gear 52 is idled by the one-way clutch 51, so the pedal P has a speed reducer. This prevents the driving force from the motor 6 from being forcibly transmitted and inadvertently applying a load to the occupant's legs.

  The switching mechanism 7 that swings the sub gear mechanism 53 to turn on and off the main gear 4 and the gear transmission mechanism 5 includes a solenoid 70 that is controlled by a control circuit 8, and the solenoid 70 serves as a free end of the bracket 56. It is pivotally attached to the formed long hole 56a. When the brake is operated, the switching mechanism 7 turns off the solenoid 70 to move the plunger backward so that the main gear 4 and the large spur gear 55 are not engaged.

  The control circuit 8 controls the motor 6 with a speed reducer 6 and the solenoid 70 based on the brake operation and the vehicle speed to maintain the requirements of the road traffic law enforcement regulations for electrically assisted bicycles. A vehicle speed control circuit based on an input from the detection mechanism 9, a motor control circuit, a solenoid control circuit, and a calculation / determination / signal generation circuit for motor control are integrated on the same substrate. For this reason, the control circuit 8 becomes compact.

  In the power unit 1, for example, when the vehicle speed is 4 km / h to 14 km / h, the motor 6 with a speed reducer and the solenoid 70 of the switching mechanism 7 are turned on, and the bicycle is in a decelerating state at 5 km or 5 km / h or the vehicle speed is 14 km / h. If it exceeds, the motor 6 with speed reducer is turned off.

  Further, when the vehicle speed is in the automatic travel mode of 10 km / h to 13 km / h, when the vehicle speed is 10 km / h or more than 10 km / h and less than 13 km, the motor 6 with a speed reducer performs forward rotation to assist the passenger's pedaling operation. However, when the vehicle speed becomes 13 km / h or higher, the motor 6 with a speed reducer performs reverse rotation. By rotating the motor 6 with a speed reducer in a reverse direction, the second bevel gear 52 is idled by the one-way clutch 51 and disconnects from the motor 6 with a speed reducer, so that the motor 6 with a speed reducer is stopped. As described above, the bicycle can be smoothly run without being unnecessarily decelerated.

  Further, when the motor 6 with speed reducer is driven on and the pedal rowing operation is not performed, the second bevel gear 52 rotates idly by the one-way clutch 51, so that an unnatural force is not applied to the occupant on the leg.

  Further, when the vehicle speed exceeds 14 km and the motor 6 with a speed reducer is stopped, the solenoid 70 of the switching mechanism 7 is turned on so that the main gear 4 and the large spur gear 55 are engaged, and the pedaling is performed. Electric power is generated by the motor 6 so that the secondary battery 2 can be charged, and the travel distance by the power assist can be extended.

  The vehicle speed detection mechanism 9 uses the teeth of the main gear 4 as an index, and the control circuit 8 calculates the vehicle speed and detects the detected vehicle speed based on intermittently blocking the light of the photocoupler by the teeth rotated as the index. By storing the vehicle speed before detection in the memory, the control circuit 8 can detect whether the bicycle is in an acceleration state or a deceleration state.

  In such a power unit 1, the lid side of the power unit case 3 is removed from the base side and separated, the main gear 4 attached to the base side of the power unit case 3 is removed, and the power unit case on the base side is removed. 3 is inserted into the crankshaft of the bicycle through the pedal hole 3a, and the power unit case 3 is locked to the bottom bracket B as shown in FIG.

  Next, the annular portion 40 of the main gear 4 is received by the six bearings 41, and the main gear 4 is rotatably arranged in the power unit case 3 on the base side.

  The main gear 4 is mounted by the mounting member 42 by sandwiching the crank A into the crank locking portion 4a of the main gear 4 and, as shown in FIG. 4, the cylinder of the bottom bracket shell S by two substantially U-shaped members 42b. The cylindrical protrusions 42d of the substantially U-shaped member 42b are fitted into the respective cylindrical holes 42e of the other substantially U-shaped member 42b to integrate them.

  Subsequently, the inner peripheral edge of the main gear 4 is pressed by the outer flanges of the two approximately half-moon shaped members 42a, and the inner flange of the approximately half-moon shaped member 42a is pressed by the inner flanges of the fixing tools 42c. And the substantially U-shaped member 42a is screwed by sandwiching the bottom bracket B, and the power unit case 3 is fixed to the bottom bracket shell S.

  Next, the power unit case 3 is fixed to the bicycle frame F by the mounting bracket 1a, and the lid-side power unit case 3 is attached to the base side. Further, the secondary battery 2 is attached to the bicycle frame F and electrically connected to the power unit 1.

  When the power-assisted bicycle is completed in this way, the power switch provided in the secondary battery 2 is turned on, and the bicycle is started by driving the pedal P on the bicycle. When the vehicle speed detection mechanism 9 detects that the vehicle speed has reached 4 km / h, the control circuit 8 outputs an operation signal for the motor 6 with a speed reducer and turns on the solenoid 70 of the switching mechanism 7 to turn on the main gear 4. And the large spur gear 55 are engaged with each other.

  When a braking operation is performed during traveling or when the vehicle speed is reduced to 5 km / h or less in a deceleration state, the control circuit 8 outputs an operation signal for turning off the motor 6 with a speed reducer. When the vehicle speed exceeds 14 km / h, the control circuit 8 outputs an off signal to the motor 6 with speed reducer. If pedaling is performed when the motor 6 with a reduction gear is stopped, regenerative power is generated and the secondary battery 2 is charged.

  Further, when the vehicle travels automatically at a speed of 10 to 13 km / h, the solenoid 70 is turned on and the motor 6 with a speed reducer rotates in the forward direction to assist pedaling. However, when the vehicle speed exceeds 13 km / h, the control circuit 8 is equipped with a speed reducer. A reverse rotation signal is output to the motor 6. Since the driving force from the first bevel gear 50 is not transmitted to the second bevel gear 52 attached to the one-way clutch 51 by the reverse rotation of the motor 6 with a speed reducer, the pedal P is driven by the drive of the motor 6 with a speed reducer. Power is not transmitted.

It is a partially cutaway front view showing an embodiment of the present invention. It is a partially notched front view which similarly shows a state differently. It is a partially cutaway rear view. It is an expanded sectional view which shows the attachment state of a main gear. It is a partially cutaway front view showing a vehicle speed detection mechanism. It is a partially notched top view which shows a gear transmission mechanism. It is a partially notched top view which shows the 1st bevel gear and the 2nd bevel gear attached to the one-way clutch. It is a perspective view which decomposes | disassembles and shows an attachment member. It is a front view which shows the bicycle which attached the power unit and the secondary battery.

Explanation of symbols

1 Power unit
1a Mounting bracket 2 Secondary battery 3 Power unit case
3a Pedal hole 4 Main gear
4a Crank locking part 5 Gear transmission mechanism 6 Motor with reduction gear 7 Switching mechanism 8 Control circuit 9 Vehicle speed detection mechanism
40 Annulus
41 Bearing
42 Mounting member
42a Almost half-moon shaped member
42b Substantially U-shaped member
42c fixture
50 1st bevel gear
51 one-way clutch
52 Second bevel gear
53 Sub gear mechanism
54 Small spur gear
55 spur gear
56 Bracket
56a oblong hole
70 Solenoid A Crank B Bottom bracket F Frame P Pedal S Bottom bracket shell

Claims (1)

  A power unit for an electrically assisted bicycle that can be retrofitted to a bicycle frame, and a gear transmission that connects a main gear provided with a crank locking portion for rotating a bicycle crank and the battery geared motor with a reduction gear. And a one-way clutch that releases the driving force of the motor with a reduction gear when there is a difference between the rotation speed of the pedal and the rotation speed of the motor with a reduction gear in the gear transmission mechanism, and is detected by the vehicle speed detection mechanism An electrically assisted bicycle comprising a switching mechanism that engages / disengages between a gear transmission mechanism and a main gear based on vehicle speed or brake operation, and a control circuit that controls on / off of a motor with a speed reducer based on vehicle speed Power unit.

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