CN201201674Y - Torque force detector for electric bicycle - Google Patents

Abstract

A torque detector for an electric bicycle includes a crank shaft, a toothed disc, and a transmission gear set for transmitting a torque from the crank shaft to the toothed disc, the transmission gear set comprising: the crank shaft gear is fixed on the crank shaft, the fluted disc gear is fixed on the fluted disc, and the sensing gear is meshed between the crank shaft gear and the fluted disc gear; and a sensor is provided to measure the bearing force of the sensing gear shaft.

Description

The torsion force indicator of Electrical Bicycle

[technical field]

The utility model is a kind of torsion force indicator, refers to a kind of device of trampling torque magnitude of detecting power-assisted electric vehicle especially, can be used to control electro-motor to export suitable auxiliary power.

[background technology]

Electrical Bicycle is quite popular in recent years product, owing to take electronic driving to sail, meets environmental protection, so become walking-replacing tool best in a lot of people mind.And present Electrical Bicycle mostly adopts the mode that drives of motor bike, control the speed of a motor vehicle by manual handle, but because of controlling of Electrical Bicycle different with mode of driving and traditional bicycle, and control is flexible unlike traditional bicycle, and it is travelled when Ordinary road can be to oneself, other people all cause certain danger.So the development of Electrical Bicycle is still restricted, also be difficult to a large amount of popularizing.

For this reason, someone starts to develop the Electrical Bicycle pattern of a new generation, form so-called assistance type Electrical Bicycle, the rider still tramples by bike by the mode of standard bicycle, but this assistance type Electrical Bicycle is provided with sensing device, cooperate rider's the force situation of trampling, order about travelling of auxiliary this assistance type Electrical Bicycle of electro-motor (electrical motor).Because the mode that drives is the same with standard bicycle, flexible operation safety is adapted to present city traffic present situation.And driving of this assistance type Electrical Bicycle is extremely light, and the rider can spend less muscle power and arrive target far away, and especially under contrary wind or loading situation, the power-assisted effect that produces by motor is more obvious.

In addition, compared to the conventional electric bicycle, because the motor of assistance type Electrical Bicycle only provides power-assisted, the accumulator load electric current is little, avoids the overdischarge phenomenon, has promptly significantly prolonged the life-span of storage battery, and use cost is also comparatively cheap.

Therefore, in simple terms, power-assisted electric vehicle is to utilize the auxiliary foot-operated legpower of motor, more comfortable light driving is provided, in order to allow the rider in the operating process of travelling, it is too little not have auxiliary power, it is arduous to trample, or auxiliary power is too big, causes electric power energy consume and harm to drive safety of operation, be according under the different condition of road surfaces, adjust the outputting power of motor, so need be established the legpower sense mechanism on the path of legpower transmission, whether the strength that puts on pedal with the sensing rider increases, and alleviates rider's the application of force according to the outputting power of sensing result control motor.

And existing tool is trampled the auxiliary type battery-driven car of torsion sensing function and mainly can be divided into two kinds of patterns: a kind ofly be simple switch control, torsion surpasses or when being lower than a certain size, promptly start or close the takeoff output of motor when trampling; Another kind is to trample torque magnitude to trample torque sensing mechanism sensing, controls the outputting power of motor with torque magnitude.First kind of power of only exporting with switch control motor often can't satisfy the power-assisted demand of rider's elasticity of demand, tramples torsion sensing mechanism so good design must be used.

The existing torsion sensing mechanism some of trampling is to adopt complicated sun and planet gear to connect elastic body torque value is converted to the beat displacement, not only complex structure, part cost of manufacture and assembly cost height, and have the tired and issuable collision of beat displacement of elastomeric resilient and influence service life or higher and increase cost to the performance requriements of part material.

Another kind of existing " force testing device of electrically assisted bicycle " of trampling No. the 03108225.4th, torsion sensing mechanism such as Chinese invention patent, as shown in Figure 7, in crank unit 50, an end of crank shaft 23 can carry out the axle supporting by bearing 51 with rotating freely.Have a barrel-contoured torsion bar 53 to connect the periphery of passing this crank shaft 23, the one end is attached to spline near the outer peripheral face of this crank shaft 23 this bearing 51, the axle supporting that the other end utilizes bearing 52 can rotate freely with respect to this crank unit 50.Pedal sprocket 25 is engaged on the other one distolateral outer peripheral face of this torsion bar 53.

Near the end of this torsion bar 53 and near the lateral surface the other end, a pair of magnet ring 55 along the circumferential direction is installed, and (55a, 55b), this magnet ring 55 is by along the circumferential direction constituting with small spacing magnetization.With the position of aforementioned magnet ring 55 subtends on, configuration pair of MR sensors 501 (501a, 501b).On output signal V1, the V2 of each MR sensor 501a, 501b, if do not produce when reversing on this torsion bar 53, the more caused initial phase difference θ ref of deviation when only producing because of the manufacturing assembling.Relative therewith, when producing on torsion bar 53 when reversing, each output signal V1, V2 are last except that aforementioned initial phase difference θ ref, the torsional capacity of also further generation and torsion bar 53, are the relevant phase difference θ F of legpower.

In order to detect the phase difference θ F that represents legpower quantitatively, the output signal V1 (V2) of each MR sensor 501a (501b), need via high-pass filter, clipping amplifier and wave shaping comparator, be input among the CPU, to the delay time n of output signal V2 with respect to output signal V1, and the cycle N of output signal V1 counts, and tries to achieve phase difference θ F.

Above-mentioned prior art trample torsion sensing mechanism, though it is simple in structure, but need high-pass filter, clipping amplifier and wave shaping comparator, signal is handled, be input among the CPU again count, comparison, computing, cost of manufacture is not low, and will have abundant signal could computing to draw to trample torsion, can postpone and can't the real-time response road conditions.

Therefore, provide the torsion force indicator that a kind of cost is low, simple in structure, sensing is used for Electrical Bicycle accurately real for necessary.

[summary of the invention]

The purpose of this utility model is to provide a kind of torsion force indicator of Electrical Bicycle, and its cost is lower, simple in structure, sensing is accurate, and adopts the directly power-assisted electric vehicle override type torsion torque sensor of detecting.

For achieving the above object, the torsion force indicator of Electrical Bicycle described in the utility model includes crank shaft, fluted disc, change-gear set, so that crank shaft torsion is delivered on the fluted disc, this change-gear set comprises at least: be fixed in crankshaft gear wheel on the crank shaft, be fixed in the fluted disc gear on the fluted disc, and be engaged on the induction gear between crankshaft gear wheel and the fluted disc gear; And be provided with sensor to measure this induction gear axle supporting power.This sensor can be piezoelectric pressure indicator (Piezoelectric PressureTransducer), load gauge (Load Cell) or strain gage (Strain Gage), and installs on this induction gear axle to measure induction gear axle supporting power.

The utility model contrast prior art has the following advantages:

1. its induction gear and crank shaft and fluted disc be with gear mesh, and the rider stands on gravity on the pedal and the tension force of chain tension can not cause error in measurement;

2. the utility model only uses simple gear structure, does not need complicated planetary wheel, and measures simply, does not need complicated circuit, and productive costs is lower;

3. the utility model does not need spring, and assembling is simple, and can not cause error in measurement because of the elastic fatigue of spring;

4. be not to utilize the beat detecting in the utility model detecting use, therefore can be arranged preferable service life.

[description of drawings]

Fig. 1 is a structural perspective of the present utility model;

Fig. 2 is a structural representation of the present utility model;

Fig. 3 is the STRESS VARIATION scheme drawing of the utility model crank axle head;

Fig. 4 is the STRESS VARIATION scheme drawing of the utility model induction gear end;

Fig. 5 sets up scheme drawing for the sensor of the utility model embodiment;

Fig. 6 is the block diagram of another embodiment of the torsion force indicator of the utility model Electrical Bicycle;

Fig. 7 is the prior art constructions scheme drawing.

[specific embodiment]

Below in conjunction with accompanying drawing the utility model is described further:

As shown in Figure 1 and Figure 2, the utility model comprises crank shaft 10, fluted disc 11, change-gear set 12, so that crank shaft 10 torsion are delivered on the fluted disc 11, this change-gear set 12 comprises at least: crankshaft gear wheel 121 is fixed on the crank shaft 10, fluted disc gear 122 is fixed on the fluted disc 11, and induction gear 123 is engaged between crankshaft gear wheel 121 and the fluted disc gear 122; And be provided with sensor 13 and measure aftermentioned induction gear axle supporting power F3.

Via aforementioned structure, its announcement has the crank length L 1 of this crank shaft 10, the tooth radius R1 of this crankshaft gear wheel 121, the tooth radius R2 of this induction gear 123, the tooth radius R3 of this fluted disc gear 122, and the fluted disc radius R 4 of fluted disc 11, when the rider tramples, produce foot-operated torsion Fp and be transferred to fluted disc gear 123 by crankshaft gear wheel 121 through induction gear 123 and drive fluted discs 11 opposing chain tension T and rotate.

As shown in Figure 3, Figure 4, when the rider tramples and begins to rotate moment, its foot-operated torsion Fp produces induction gear antagonistic force F1 because of being subjected to crankshaft gear wheel 121 with induction gear 123 effects, and this induction gear 123 produces fluted disc gear antagonistic force F2 with fluted disc gear 123 same interactions.Therefore, this induction gear 123 is subjected to crankshaft gear wheel directed force F 1 and fluted disc gear antagonistic force F2, and the induction gear axle supporting power F3 of these induction gear 123 axle center generation itself, then obtains following formula (I):

$F3=F1+F2=2\mathrm{Fp}\×\frac{L1}{R1}..........\left(I\right)$

Therefore in other words, as long as can record induction gear axle supporting power F3, can derive and obtain trampling torsion Fp (pedal force).So how this sensor 13 obtains induction gear axle supporting power F3, promptly becomes the main consideration that this sensor 13 sets up.

As shown in Figure 5, be the embodiment that a preferable sensor 13 sets up, described sensor 13 can be piezoelectric pressure indicator (Piezoelectric Pressure Transducer), load gauge (Load Cell) or strain gage (Strain Gage), it mainly is to be erected at this induction gear 123 shaft core positions, can obtain induction gear axle supporting power F3, this sensor 13 puts aside that beat displacement or displacement are little of can slightly not disregarding.Have fixed end 1231 and measuring end 1232 in this induction gear 123 axle center extension, 13 of this sensors are arranged on measuring end 1232 positions, obtain this induction gear 123 and 1231 length of support L2 of fixed end by this, induction gear 123 and 1232 length of support L3 of measuring end; And the fixed end axle supporting power F4 on the induction gear fixed end 1231, the measuring end axle supporting power F5 on the induction gear measuring end 1232 obtains following formula (II) after computing:

$F3=F5\×\frac{L1+L3}{L2}..............\left(\mathrm{II}\right)$

So, as long as learn measuring end axle supporting power F5, can derive induction gear axle supporting power F3 easily, so this sensor 13 can be arranged on the measuring end 1232 of this induction gear 123, directly recording measuring end axle supporting power F5, and and then derive to trampling torsion Fp.Therefore,, can react at any time and trample torsion Fp by simple sensors 13 designs, and with external motor real-Time Compensation outputting power.

As Fig. 6 is another embodiment of the present utility model, it has change-gear set 14, it is fixing with crank shaft 10 to include crank shaft helical wheel 141, induction helical wheel 142 is meshed with crank shaft helical wheel 141 and is hubbed on the induction helical gear shaft 143 with bearing, this sensor 13 is set up on this induction helical gear shaft 143 to obtain measuring end axle supporting power F5, transmission helical wheel 144 is meshed with induction helical wheel 142 and fixed conveyor spur gear 145 rotates synchronously, aforementioned each helical wheel 141,142,144 set up with suitable bearing and axle supporting with transmission spur gear 145, and fluted disc spur gear 146 is fixed in and is meshed with above-mentioned transmission spur gear 145 on the fluted disc 11 and is hubbed on the crank shaft with bearing.Therefore, this embodiment utilizes the gear cluster variation to make crank shaft 10 coaxial with fluted disc 11, and obtains identical inducing function.

The above only is a preferable embodiment of the present utility model; protection domain of the present utility model is not limited thereto, and those of skill in the art are any to be included within the utility model protection domain based on non-material change on the technical solutions of the utility model.

Claims (5)

1. A torque detector of electric bicycle, it is characterized in that, it comprises: crankshaft; Chainring; a variable speed gear set comprising crankshaft gears, chainring gears and induction gears; and sensor; The variable speed gear set is arranged between the crankshaft and the chainring, the crankshaft gear is fixed on the crankshaft, the chainring gear is fixed on the chainring, and the induction gear meshes between the crankshaft gear and the chainring gear. And the sensor is arranged at the axis position of the induction gear. 2. The torque detector for electric bicycle according to claim 1, wherein the sensor can be a piezoelectric pressure sensor, a load gauge or a strain gauge. 3 . The torque detector for an electric bicycle as claimed in claim 1 , wherein the axis extension of the induction gear has a fixed end and a measuring end, and the sensor is arranged at the measuring end. 4 . 4. A torque detector for an electric bicycle, characterized in that it comprises: crankshaft; Chainring; a variable speed gear set comprising crankshaft helical gears, induction helical gears, transmission helical gears, transmission spur gears and chainring spur gears, and; sensor; The speed change gear set is arranged between the crankshaft and the chainring, the crankshaft helical gear is fixed to the crankshaft, the induction helical gear meshes with the crankshaft helical gear and is pivoted on the induction helical gear shaft with a bearing, and the sensor is erected On the induction helical gear shaft, the transmission helical gear meshes with the induction helical gear and fixes the transmission spur gear to rotate synchronously. The chainring spur gear is fixed on the chainring to mesh with the transmission spur gear and is pivoted on the crank with a bearing On the shaft; the aforementioned helical gears and spur gears are all erected with appropriate bearings and shaft supports. 5 . The torque detector for an electric bicycle as claimed in claim 1 , wherein the sensor is a piezoelectric pressure sensor, a load gauge or a strain gauge.

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