DE202024100377U1 - Mid-engine structure for electric bikes - Google Patents

Abstract

Mid-motor (100), which is used to transmit the electrical driving force and the pedaling force to a chain wheel (210) and comprises the following: a gear mechanism (130) which is housed in a housing (110) and at least one located in a ring gear (131). and a planet gear (132, 133) in engagement with it, two planet carriers (134, 135) located on opposite sides of the planet gears (132, 133) and several for locking the two opposite planet carriers (134, 135) and for passing them through the planet gears (132, 133) serving locking elements (137); an eccentric shaft (140) which has a shaft tube (141), one end of the shaft tube being provided with at least one eccentric section (142, 143) and a respective eccentric section (142, 143 ) is arranged offset relative to the shaft tube (141) and is inserted into the gear mechanism (130) and coupled to the planetary gears (132, 133); an electric drive device (120) which comprises a rotatable rotor (122) and is fixedly connected to a part of the Shaft tube (141) of the eccentric shaft (140); a crankshaft (150) which passes through the axial interior of the eccentric shaft (140) and is coupled to the eccentric section (141) of the eccentric shaft (140) via a bearing rolling element (185). ;a gap (200) which is provided between the inner wall surface of the shaft tube (141) of the eccentric shaft (140) and the outer surface of the crankshaft (150);a sprocket output shaft (160) which is connected via a first clutch (171) to the Gear mechanism (130) and coupled to the crankshaft (150) via a second clutch (172), the sprocket output shaft (160) being combined with the sprocket (210); a torque detector which is combined with a strain gauge (180a). specially shaped bearing holder (180) and coupled via a bearing to the sprocket output shaft (160), the specially shaped bearing holder (180) being attached to the housing (110);wherein the rotor (122) the eccentric shaft (140) and drives the planet gears (132, 133) to rotate and the planet gears (132, 133) in the ring gear (131) carry out an eccentric orbital movement, whereby the two planet carriers (134, 135) are driven to rotate, the driving force being transmitted via the first clutch ( 171) is transmitted to the sprocket output shaft (160), the rotation of the crankshaft (150) is transmitted to the sprocket output shaft (160) via the second clutch (172) and the torque detector for detecting the torque of the sprocket output shaft (160 ) serves.

Description

Field of invention

The present invention relates to the technical field of electric bicycles and more particularly to a mid-engine usable for electric bicycles.

State of the art

As a rule, the chainring and chain of a bicycle are driven forward by pedaling. Electric bicycles are equipped with an electric machine (motor) that serves as an auxiliary power. Just by pedaling, the power provided by the engine can be used as an auxiliary power, making riding easier and therefore less labor intensive.

Most well-known electric bicycle mid-motors use planetary gear mechanisms as reduction mechanisms. For example, a planetary gear mechanism includes a ring gear, a sun gear is installed inside the ring gear, and planetary gears are engaged with the ring gear and the sun gear. Taiwan Utility Models TWM 437304 and TWM 384160 disclose the reduction mechanisms of a mid-motor for electric bicycles, wherein the planetary gear mechanisms provided by the reduction mechanisms do not include a sun gear. In addition, these utility models do not disclose a torque sensor.

Task of the invention

It is an object of the present invention to provide a mid-motor structure for electric bicycles, through which the advantageous effects of simplifying the structure and reducing the volume and further reducing the rotation interference between the electric drive and the pedal drive can be achieved.

In order to achieve the above-mentioned objects and to achieve the advantageous effects, the present invention provides a mid-motor for transmitting the electric driving force and the pedaling force to a sprocket, comprising: a gear mechanism housed in a housing and at least one in a planet gear located on a ring gear and in engagement with it, two planet carriers located on opposite sides of the planet gears and a plurality of locking elements used to lock the two opposite planet carriers and to pass through the planet gears; an eccentric shaft having a shaft tube, one end of the shaft tube being provided with at least one eccentric portion and a respective eccentric portion being offset relative to the shaft tube and inserted into the gear mechanism and coupled to the planetary gears; an electric drive device comprising a rotatable rotor and fixedly connected to a part of the shaft tube of the eccentric shaft; a crankshaft which passes through the axial interior of the eccentric shaft and is coupled to the eccentric section of the eccentric shaft via a bearing rolling element; a gap provided between the inner wall surface of the shaft tube of the eccentric shaft and the outer surface of the crankshaft and in which no other members are accommodated; a sprocket output shaft coupled to the gear mechanism via a first clutch and to the crankshaft via a second clutch, the sprocket output shaft being combined with the chainring assembly; and a torque detector including a specially shaped bearing bracket and coupled to the sprocket output shaft via a bearing, the specially shaped bearing bracket secured to the housing; wherein the rotor drives the eccentric shaft and the planet gears to rotate and the planet gears in the ring gear perform an eccentric orbital movement, whereby the two planet carriers are driven to rotate, the driving force being transmitted to the sprocket output shaft via the first clutch, the rotation of the crankshaft over the second clutch is transmitted to the sprocket output shaft and the torque detector is used to detect the torque of the sprocket output shaft.

Brief description of the drawings

• 1 shows a sectional view of an embodiment according to the present invention in the combined state;
• 2 shows an appearance view of the eccentric shaft of the embodiment according to the present invention;
• 3 1 shows an exploded view of the gear mechanism of the embodiment according to the present invention;
• 4 shows a schematic view of the eccentric shaft and the planetary gears of the embodiment according to the present invention in the combined state;
• 5 shows a schematic view of the planet gears and the ring gear of the embodiment according to the present invention in the engaged state.

Detailed description of the exemplary embodiment

It will be on 1 Referenced. The mid-engine 100 shown in the exemplary embodiment can be used for electric bicycles. The mid-engine 100 comprises a housing 110 consisting of a first housing part 111 and a second housing part 112 connected to it; an electric drive device 120 accommodated in the housing 110; a gear mechanism 130 accommodated in the housing 110, an eccentric shaft 140 accommodated in the housing 110 and coupled to the electric drive device 120 and the gear mechanism 130, and a crankshaft 150 accommodated in the housing 110 and guided through the axial interior of the eccentric shaft 140. The mid-engine 100 further comprises a chain wheel - Output shaft 160, which is coupled to the gear mechanism 130 via a first clutch 171 and to the crankshaft 150 via a second clutch 172, and a specially shaped bearing holder 180 firmly connected in the housing 110, the sprocket output shaft 160 passing through the axial center of the Specially shaped bearing holder 180 is carried out, the sprocket output shaft 160 is coupled to a sprocket 210 and the two ends of the crankshaft 150 are each connected to a crank 220.

Further, the specially shaped bearing bracket 180 is provided with a supporting rolling member 181 such as a bearing coupled to the sprocket output shaft 160. The specially shaped bearing holder 180 may be a disc member and a strain gauge 180a may be attached to its surface. Accordingly, the entire bracket can be used as a torque detector to detect the torque of the sprocket output shaft 160 and thus ensure the function of detecting the torque on the sprocket output shaft 160. In addition, a speed detector 190 is coupled to the crankshaft 150, which corresponds to the electric drive device 120. The speed detector 190 includes, among other things, a detection point and a disk consisting of several magnets, the disk rotating together with the crankshaft 150 and, when the magnets pass the detection point, a signal is sent to the controller, which corresponds to the transmission of a real-time cadence signal corresponds, with the cadence being used as the basis for determining the movement conditions.

In the exemplary embodiment, the first clutch 171 and the second clutch 172 are unidirectional elements, which can include, among other things, overrunning clutches or pawl clutches, whereby in the case of an overrunning clutch, the self-coupling function is achieved by the change in speed or change in the direction of rotation of the drive part and the driven part. Furthermore, in terms of configuration, bearing rolling elements 182, 183, 184, 185, 186, 187 such as bearings can be arranged in appropriate shape and number at the predetermined positions of all elements so as to couple them with the corresponding elements. For example, the bearing rolling elements 182 to 184 are arranged between the eccentric shaft 140 and the gear mechanism 130, with the bearing rolling element 185 between the eccentric shaft 140 and the crankshaft 150, the bearing rolling element 186 between the gear mechanism 130 and the sprocket output shaft 160 and the bearing rolling element 187 is arranged between the sprocket output shaft 160 and the crankshaft 150.

It will be on 2 Reference is made, which shows a view of the appearance of the eccentric shaft 140 according to the embodiment. The axial interior of the eccentric shaft 140 is a passageway through the structure. Furthermore, the eccentric shaft 140 comprises a shaft tube 141 with a predetermined length, wherein a first eccentric section 142 and a second eccentric section 143 are formed at one end of the shaft tube 141 or connected thereto and the first eccentric section 142 and the second eccentric section 143 adjoin one another and are arranged offset from one another are. In addition, both the first eccentric section 142 and the second eccentric section 143 are arranged eccentrically relative to the shaft tube 141. In addition, the first eccentric portion 142 and the second eccentric portion 143 are cylindrical and have outer diameters larger than the outer diameter of the shaft tube 141.

It will open again 1 Referenced. The electric drive device 120 includes a stator 121 and a rotor 122, wherein the stator 121 is fixed in the housing 110, the rotor 122 is located in the middle of the stator 121, and after the electric drive device 120 is turned on, the rotor 122 can be driven to to rotate relative to the stator 121. Furthermore, a part of the shaft tube 141 of the eccentric shaft 140 is inserted into the rotor 122, the shaft tube 141 being suitably firmly connected to the rotor 122, whereby the rotor 122 can set the eccentric shaft 140 in rotation. Furthermore, the crankshaft 150 is guided through the axial interior of the eccentric shaft 140, with a gap 200 between the crankshaft 150 and the axial inner wall of the eccentric shaft 140, in particular between the outer surface of the crankshaft 150 and the inner wall of the shaft tube 141, and no further elements are accommodated in the gap 200.

It will be on 3 Reference is made, which shows an exploded view of the gear mechanism 130 according to the embodiment. The gear mechanism 130 includes a ring gear 131, a first planet gear 132, a second planet gear 133, a first planet carrier 134 and a second planet carrier 135, which are connected to a rolling element 138, the inner peripheral surface of the ring gear 131 being provided with internal teeth 131a, which The outer peripheral surface of the first planetary gear 132 is provided with external teeth 132a, the outer peripheral surface of the second planetary gear 133 is provided with external teeth 133a, and the first planetary gear 132 and the second planetary gear 133 face each other and are accommodated in the ring gear 131 and each through the external teeth 132a, 133a engage with the internal toothing 131a. In addition, a spacer ring 139 is arranged between the two opposing planet gears 132, 133, whereby mutual interference in the operation of the two planet gears 132, 133 is avoided. It is worth noting that in the present embodiment, the number of teeth of the internal teeth 131a is larger than the number of teeth of the external teeth 132a, 133a so that the number of teeth between them does not differ too much.

Furthermore, the first planet gear 132 and the second planet gear 133 are each provided with a plurality of through holes 132b, 133b, with a plurality of sleeves 136a and a plurality of shaft bushings 136b combined with them being accommodated in the corresponding through bores 132b, 133b and the shaft bushings 136b being accommodated in the corresponding shaft bushings 136a are. The first planet carrier 134 is for arrangement on one side (the outside) of the first planet gear 132 and the second planet carrier 135 is for arrangement on one side (the outside) of the second planet gear 133, with a plurality of locking elements 137 each through the first planet carrier 134, namely through the sleeves 136a and the shaft bushings 136b combined with them and are locked with the second planet carrier 135. In this way, the two planet carriers 134, 135 and the two planet gears 132, 133 are combined with one another in one piece by means of the corresponding locking elements 137. Furthermore, the outer diameter of a respective sleeve 136a is smaller than the inner diameter of a corresponding through hole 132b, 133b. According to the description of the combination of the above elements, the two end surfaces of a respective shaft bushing 136b may be in contact with the planet carrier 134, 135, respectively, thereby adjusting the preload of a respective rolling member (bearing) 138 located on the planet carrier 134, 135. Furthermore, there is a loose fit between a respective shaft bushing 136b and the corresponding locking element 137.

It will be on 4 Reference is made, which shows a schematic view according to the embodiment in which the eccentric shaft 140 is coupled to the first planet gear 132 and the second planet gear 133. The first planet gear 132 is attached to the first eccentric section 142 and the second planet gear 133 to the second eccentric section 143. Since the first eccentric portion 142 and the second eccentric portion 143 are offset from each other, the first planetary gear 132 and the second planetary gear 133 are eccentric relative to the shaft tube 141.

It will be on 5 Referenced. According to the description of the above embodiment, the first planetary gear 132 and the second planetary gear 133 are offset from each other, therefore, the engagement positions of the first planetary gear 132 and the second planetary gear 133 each engaged with the ring gear 131 have a phase difference. The phase difference between the two planet gears 132, 133, which are each in engagement with the ring gear 131, is preferably 180°. Furthermore, the tooth shape of the internal tooth structure of the ring gear 131 may be an involute tooth shape or a cycloid tooth shape and the tooth shape of the external tooth structure of a respective planetary gear 132, 133 may be an involute tooth shape or a cycloid tooth shape. When the planet gears 132, 133 are rotated, the sleeves 136a and the corresponding through holes 132b, 133b are in rolling contact with each other. Furthermore, the sleeves 136a and the corresponding through holes 132b, 133b are rotatable relative to one another to form a rotational fit.

It will open again 1 Referenced. The electric drive device 120 provides a torque, whereby the rotor 122 drives the eccentric shaft 140 to rotate. Since there is a gap 200 between the axial interior of the eccentric shaft 140 and the crankshaft 150 and the eccentric shaft is coupled to the bearing rolling element 185, the actuating force of the electric drive device 120 is not transmitted to the crankshaft 150. Furthermore, the two eccentric sections 142, 143 of the eccentric shaft 140 each drive the two planet gears 132, 133 so that they carry out an eccentric orbital movement in the ring gear 131, whereby the first planet carrier 134 and the second planet carrier 135 are driven, the actuating torque of the second Planet carrier 135 is transmitted via the first clutch 171 to the sprocket output shaft 160.

The crankshaft 150 is rotated by the pedaling force applied to the crank. Since there is a gap 200 between the axial interior of the eccentric shaft 140 and the crankshaft 150 and the eccentric shaft is coupled to the bearing rolling element 185, the actuating force of the crankshaft 150 is not transmitted to the eccentric shaft 140. Furthermore, the pedaling force received by the crankshaft 150 is transmitted to the sprocket output shaft 160 via the second clutch 172.

In the structural configuration of the present embodiment, in the sprocket output shaft 160, the first clutch 171 and the second clutch 172 carry the output torque of the electric drive device 120 and the crankshaft 150 alone or together. Furthermore, the desired drive effect can be achieved in the gear mechanism 30 simply by using a single planet gear 132 or 133. However, if a structure is used in which the phase difference between the two planet gears 132, 133 and the gear ring in engagement with the two is 131180 °, this ensures more stable rotation for the two planet gears 132, 133 and for the planet carriers 134, 135 , each driven by the two planet gears 132, 133, for more stable rotation. Furthermore, in the present embodiment, the two planet carriers 134, 135 are located on opposite sides of the gear mechanism 130. This configuration not only ensures that the entire gear mechanism 130 has high structural rigidity, but also ensures the effect of more balanced and stable operation, when the gear mechanism 130 is in operation.

In the present exemplary embodiment, the crankshaft 150 is guided through the axial interior of the eccentric shaft 140, with a gap 200 between the axial interior of the eccentric shaft 140 and the crankshaft 150, so that the crankshaft 150 that absorbs the pedaling force and the eccentric shaft 140 that absorbs the electrical drive force are coaxial form a combined structure and thus the effect of streamlining the structure and reducing the volume can be achieved and the number of bearing rolling elements can be reduced in order to reduce the rotation interference between the electric drive and the pedal drive. In addition, the specially shaped bearing bracket 180 and the speed detector 190 are housed in the housing 110 and coupled to the sprocket output shaft 160 and the crankshaft 150, so that the mid-engine 100 can be made smaller overall.

Reference symbol list

100

Mid-engine

110

Housing

111

first housing part

112

second housing part

120

Electric drive device

121

stator

122

rotor

130

Gear mechanism

131

ring gear

131a

Internal gearing

132

first planetary gear

132a

External gearing

132b

Through hole

133

second planetary gear

133a

External gearing

133b

Through hole

134

first planetary carrier

135

second planet carrier

136a

sleeve

136b

shaft bushing

137

Locking element

138

Rolling element

139

Spacer ring

140

eccentric shaft

141

Wave tube

142

first eccentric section

143

second eccentric section

150

crankshaft

160

Sprocket output shaft

171

first clutch

172

second clutch

180

specially shaped bearing bracket

180a

Strain gauges

181, 182, 183, 184, 185, 186, 187

bearing rolling element

190

Speed detector

200

gap

210

Sprocket

Claims (10)

Mid-engine (100), which is used to transmit the electrical driving force and the pedaling force to a chain wheel (210) and comprises the following: a gear mechanism (130) which is housed in a housing (110) and at least one planet gear (132, 133) located in a gear ring (131) and in engagement with it, two located on opposite sides of the planet gears (132, 133). Planet carrier (134, 135) and a plurality of locking elements (137) used to lock the two opposite planet carriers (134, 135) and to pass through the planet gears (132, 133); an eccentric shaft (140) which has a shaft tube (141), one end of the shaft tube being provided with at least one eccentric section (142, 143) and a respective eccentric section (142, 143) being arranged offset relative to the shaft tube (141) and in the gear mechanism (130) is inserted and coupled to the planet gears (132, 133); an electric drive device (120) comprising a rotatable rotor (122) and fixedly connected to a part of the shaft tube (141) of the eccentric shaft (140); a crankshaft (150) which passes through the axial interior of the eccentric shaft (140) and is coupled to the eccentric section (141) of the eccentric shaft (140) via a bearing rolling element (185); a gap (200) provided between the inner wall surface of the shaft tube (141) of the eccentric shaft (140) and the outer surface of the crankshaft (150); a sprocket output shaft (160) coupled to the gear mechanism (130) via a first clutch (171) and to the crankshaft (150) via a second clutch (172), the sprocket output shaft (160) being coupled to the sprocket (210) is combined; a torque detector comprising a specially shaped bearing bracket (180) combined with a strain gauge (180a) and coupled to the sprocket output shaft (160) via a bearing, the specially shaped bearing bracket (180) being secured to the housing (110); wherein the rotor (122) drives the eccentric shaft (140) and the planet gears (132, 133) to rotate and the planet gears (132, 133) in the ring gear (131) carry out an eccentric orbital movement, whereby the two planet carriers (134, 135). Rotation are driven, the driving force being transmitted to the sprocket output shaft (160) via the first clutch (171), the rotation of the crankshaft (150) being transmitted to the sprocket output shaft (160) via the second clutch (172) and the torque detector is used to detect the torque of the sprocket output shaft (160). Mid-engine after Claim 1 , in which the number of planetary gears of the gear mechanism (130) is two, the planetary gears include a first planetary gear (132) and a second planetary gear (133), the number of eccentric sections of the eccentric shaft (140) is two, the eccentric sections have a first eccentric section ( 142) and a second eccentric section (143), the first planetary gear (132) is coupled to the first eccentric section (142), the second planetary gear (133) is coupled to the second eccentric section (143), the number of teeth of the first planetary gear (132) and the second planetary gear (133) is smaller than the number of teeth of the ring gear (131) and the phase difference between the engagement positions of the first planetary gear (132) and the second planetary gear (133) which are connected to the ring gear (131) in The engagement is 180°. Mid-engine after Claim 1 , in which the first clutch (171) and the second clutch (172) are overrunning clutches. Mid-engine after Claim 1 , in which the first clutch (171) and the second clutch (172) are pawl clutches. Mid-engine after Claim 1 or 2 , in which the planet gears (132, 133) each have a plurality of through holes (132b, 133b), a combination piece in which a shaft bushing (136b) is inserted into a sleeve (136a) being arranged in a respective through hole (132b, 133b). is, the outer diameter of a respective sleeve 136a is smaller than the inner diameter of the corresponding through hole (132b, 133b) and the locking elements (137) are locked with the two planet carriers (134, 135) and through the in the corresponding through holes (132b, 133b). Planetary gears (132, 133) located shaft bushings (136b) are carried out. Mid-engine after Claim 5 , in which a respective sleeve (136a) and the corresponding shaft bushing (136b) form a rotational fit and a respective shaft bushing (136b) and the corresponding corresponding locking element (137) form a loose fit. Mid-engine after Claim 1 , in which the electric drive device (120) comprises a stator (121) attached to the housing (110), the rotor (122) being arranged in the middle of the stator (121). Mid-engine after Claim 1 , further comprising a speed detector (190) which is coupled to the crankshaft (150) and corresponds to the electric drive device (120). Mid-engine after Claim 1 , in which the ring gear (131) has an internal tooth structure and the tooth shape of the internal tooth structure is an involute tooth shape, wherein a respective planet gear (132, 133) has an external tooth structure and the tooth shape of the external tooth structure is an involute tooth shape. Mid-engine after Claim 1 , in which the ring gear (131) has an internal tooth structure and the tooth shape of the internal tooth structure is a cycloid tooth shape, wherein a respective planet gear (132, 133) has an external tooth structure and the tooth shape of the external tooth structure is a cycloid tooth shape.

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