Transmission device for electric power-assisted bicycle

Abstract

The utility model relates to a transmission device for an electric power-assisted bicycle, which is characterized in that a crank shaft is a hollow shaft, a splined hole is arranged at the front end inside the crank shaft, and two cycloidal gears are respectively matched with two eccentric circle parts on the crank shaft through a cycloidal gear supporting bearing in a rotating and supporting way; the output disc is in rotary support fit with the rear section of the crankshaft through a crank support bearing; the rear sections of the plurality of pins are fixedly inserted into the plurality of pin positioning holes in the output disc respectively, and the front sections of the plurality of pins are inserted into the plurality of pin matching holes in the two cycloidal gears respectively to form driving matching; the pin wheel housing is sleeved outside the two cycloidal gears and the output disc; a plurality of gear pins are uniformly embedded in the front section of the inner wall of the gear pin housing to form an annular gear pin group; the two cycloidal gears are both internally meshed with the annular pin gear group; the rear section of the inner wall of the pin wheel housing is rotationally supported and matched with the outer circle of the output disc through an output disc supporting bearing; the front end pressing plate and the rear end pressing plate are fixedly installed at the front end and the rear end of the pin wheel housing respectively. The transmission device has the advantages of being small in axial size and size and light in weight.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric power-assisted bicycles, and in particular relates to a transmission device for electric power-assisted bicycles. Background Art

[0002] In addition to being energy-saving, economical, and environmentally friendly, electric-assisted bicycles also have the labor-saving and time-saving features of motor vehicles, which meet the consumption characteristics and needs of today's Chinese consumers. They refer to mechatronic personal transportation vehicles that use batteries as auxiliary energy sources on the basis of ordinary bicycles and are equipped with drive devices, controllers, batteries, throttles, brake handles and other operating components and display instrument systems. The drive device of an electric-assisted bicycle consists of a motor and a transmission device, which is very sensitive to weight and volume, so lightweight and miniaturization of the drive device is a development trend. Due to application needs and technological advances, there are now increasingly stringent requirements on the speed ratio, volume, and weight of the drive device.

[0003] Therefore, it is of great significance to optimize the weight and volume of the drive device. Utility Model Content

[0004] The purpose of the utility model is to overcome the shortcomings of the prior art and provide a small-volume and lightweight electric-assisted bicycle transmission device.

[0005] The above-mentioned purpose of the utility model is achieved through the following technical solutions:

[0006] A transmission device for an electric power-assisted bicycle, characterized in that it comprises a pinion housing, two cycloid wheels, a crank shaft, an output disc, a pin, a pinion pin, a front end pressure plate, a rear end pressure plate, a crank support bearing, a cycloid wheel support bearing, and an output disc support bearing;

[0007] The crankshaft is a hollow shaft, and the portion of the crankshaft inner hole near the front end adopts a spline hole structure; the front section of the crankshaft is provided with two eccentric circles at an angle of 180 degrees, constituting the crank section of the crankshaft; the two cycloid wheels are respectively supported by the two eccentric circles on the crankshaft through a cycloid wheel support bearing to form a rotational support, and a plurality of pin matching holes are evenly distributed along the circumferential direction on the two cycloid wheels; the output disk is supported by the rear section of the crankshaft through the crank support bearing; a plurality of pin positioning holes are evenly distributed along the circumferential direction on the side of the output disk close to the cycloid wheel; the rear sections of the plurality of pins are respectively inserted and fixed in the plurality of pin positioning holes, and the front sections of the plurality of pins are respectively inserted into the plurality of pin matching holes on the two cycloid wheels to form a driving fit;

[0008] The pin gear housing is sleeved on the outside of the two cycloid wheels and the output disc; the front section of the inner wall of the pin gear housing is evenly inlaid with a plurality of pin gear pins to form an annular pin gear group; the two cycloid wheels are internally meshed with the annular pin gear group; the rear section of the inner wall of the pin gear housing is supported by the output disc support bearing and the outer circle of the output disc to form a rotation support fit;

[0009] The front end pressure plate and the rear end pressure plate are both annular pressure plates, which are fixedly mounted on the front end and the rear end of the pin gear housing respectively;

[0010] External threaded holes connected to the motor of the transmission device or the frame of the electric power-assisted bicycle are evenly distributed along the circumferential direction on the front pressure plate; external threaded holes connected to the output actuator of the electric power-assisted bicycle are evenly distributed along the circumferential direction at the rear end of the output disk.

[0011] Moreover, a screw through hole is provided at a position corresponding to each pin positioning hole on the output disk, and the screw through hole adopts a countersunk hole; the pin adopts a stepped pin shaft which is thick at the front and thin at the back, and a threaded hole is provided at the center of the pin; a weight reduction hole is provided at the front end of the threaded hole in the center of the pin; multiple pins are respectively plugged and matched with multiple pin positioning holes on the output disk through their respective rear sections, and the pins are fixed to the output disk through the threaded holes installed on the pins and the screws in the corresponding screw through holes on the output disk.

[0012] Moreover, the cycloid wheel is made of lightweight composite material.

[0013] Moreover, weight-reducing holes are evenly distributed on the output disc along the circumferential direction.

[0014] The advantages and positive effects of the utility model are:

[0015] 1. The utility model adopts a structural form in which the cycloid wheel and the output disc are respectively installed at the front and rear ends of the crank shaft, and the fixed installation of the transmission device is realized by installing the front pressure plate on the pinion housing. Compared with the existing conventional reduction transmission device, the axial size is greatly reduced and the volume is reduced.

[0016] 2. The transmission device is hollow as a whole, which is convenient for passing external cables, transmission shafts and other components, reduces the possibility of interference and facilitates installation.

[0017] 3. The components of this transmission device are made of lightweight materials and have a reasonable weight-reducing hole structure, which achieves the lightweight of the device.

[0018] 4. This transmission device adopts a cycloid reduction mechanism, which has the characteristics of large speed ratio and wide speed ratio coverage.

[0019] 5. The complexity of the transmission mechanism is reduced, which increases reliability; the weight and processing cost are greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a longitudinal sectional view of the utility model;

[0021] Figure 2 It is a three-dimensional exploded view of the utility model;

[0022] Figure 3 This is the appearance of the utility model Figure 1 ;

[0023] Figure 4 This is the appearance of the utility model Figure 2 . DETAILED DESCRIPTION

[0024] The structure of the utility model is further described below with reference to the accompanying drawings and through embodiments. It should be noted that the embodiments are descriptive rather than restrictive.

[0025] A transmission device for an electric-assisted bicycle, see Figure 1-Figure 4 The invention point is: it mainly includes a pin gear housing 2, two cycloid wheels 5, a crank shaft 7, an output disc 12, a pin 8, a pin gear pin 4, a front end pressure plate 3, a rear end pressure plate 9, a crank support bearing 13, a cycloid wheel support bearing 6, and an output disc support bearing 10.

[0026] The crankshaft adopts a hollow structure, which can effectively reduce the weight of the mechanism and can pass cables, shafts, etc. The part near the front end of the crankshaft inner hole adopts a spline hole structure, which is used to cooperate with the output shaft of the motor through spline transmission to form a driving device of the electric power-assisted bicycle. The front section outside the crankshaft is provided with two eccentric circular parts at 180 degrees, which constitute the crank part of the crankshaft. The crank part is used to cooperate with two cycloid wheels.

[0027] The two cycloid wheels are respectively supported and rotated with the two eccentric circles on the crankshaft through a cycloid wheel support bearing. Multiple pin matching holes are evenly distributed along the circumferential direction on the two cycloid wheels for slidingly matching with the pins, so as to output the rotational motion of the cycloid wheels through the output disk. The cycloid wheels are made of lightweight composite materials, such as polyetheretherketone, polyoxymethylene, etc., which greatly reduces the weight of the whole machine.

[0028] The output disc forms a rotation support with the rear section of the crankshaft through the crank support bearing. A plurality of pin positioning holes are evenly arranged along the circumferential direction on the side of the output disc close to the cycloid wheel, and a screw through hole is arranged at the position corresponding to each pin positioning hole on the output disc, and the screw through hole adopts a countersunk hole. The pin positioning holes on the output disc correspond to the pin matching holes on the two cycloid wheels one by one. The rear end of the output disc is evenly arranged along the circumferential direction with external threaded holes for connecting the output actuator. In addition, weight reduction holes are evenly arranged along the circumferential direction on the output disc to achieve a better lightweight effect of the transmission device.

[0029] The pin is used to transmit the movement of the cycloid wheel to the output disk. The pin adopts a stepped pin shaft that is thick at the front and thin at the back, and a threaded hole is set at the center of the pin. In order to reduce the gravity of the pin and achieve a better lightweight effect of the transmission device, a weight reduction hole is set at the front end of the threaded hole in the center of the pin. The multiple pins are respectively plugged into and matched with the multiple pin positioning holes on the output disk through their respective rear sections, and the pins are fixed to the output disk through the threaded holes installed on the pins and the screws 11 in the corresponding screw holes on the output disk. The front sections of the multiple pins are respectively inserted into the pin matching holes on the two cycloid wheels to form a driving match.

[0030] The pin gear housing is sleeved on the outside of the two cycloid wheels and the output disc. The front section of the inner wall of the pin gear housing is evenly inlaid with multiple pin gear pins to form an annular pin gear group; the two cycloid wheels are meshed with the annular pin gear group. The rear section of the inner wall of the pin gear housing forms a rotation support match with the outer circle of the output disc through the output disc support bearing.

[0031] The front and rear pressure plates are both annular pressure plates, which are fixed to the front and rear ends of the pin gear housing by multiple screws evenly arranged in the circumferential direction. External threaded holes are evenly arranged in the circumferential direction on the front pressure plate, which can connect the transmission device to the motor of the transmission device or the frame of the electric power-assisted bicycle. The rear pressure plate cooperates with the shoulder in the inner hole of the pin gear housing, the shoulder on the outer circle of the output disc, and the shaft retaining ring 16 embedded in the output disc to achieve axial limitation of the output disc support bearing.

[0032] In addition to the above main technical features, an adjustment washer 15 is provided between the two crankshaft support bearings, and an elastic retaining ring 14 is installed on the rear side of the crankshaft support bearing located at the rear end, which cooperates with the shoulder on the crankshaft and the shoulder provided in the inner hole of the output disc to realize the axial limitation of the two crankshaft support bearings. The axial limitation of the two cycloid wheel support bearings refers to the limitation method of the two crankshaft support bearings, which will not be repeated here.

[0033] The working principle of the transmission device for the electric power bicycle is as follows:

[0034] The crankshaft cooperates with the cycloid wheel through the cycloid wheel support bearing as the input of the transmission, and the needle tooth pin is inserted into the needle tooth housing to cooperate with the cycloid wheel; the crankshaft drives the cycloid wheel to rotate by rotating. Since the rotation axes of the crankshaft, the needle tooth housing and the output disk coincide, the movement form of the cycloid wheel is: it makes circular motion around the above-mentioned rotation axis and rotates on itself, and the cycloid wheel is determined by meshing with the needle tooth pin; the column pin slides with the column pin matching hole on the cycloid wheel and is fastened to the output disk at the same time, and finally the movement of the cycloid wheel is output through the output disk.

[0035] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A transmission device for an electric power-assisted bicycle, characterized in that: It includes a pin gear housing, two cycloid wheels, a crank shaft, an output disc, a column pin, a pin gear pin, a front end pressure plate, a rear end pressure plate, a crank support bearing, a cycloid wheel support bearing, and an output disc support bearing; The crankshaft is a hollow shaft, and the portion of the crankshaft inner hole near the front end adopts a spline hole structure; the front section of the crankshaft is provided with two eccentric circles at an angle of 180 degrees, constituting the crank section of the crankshaft; the two cycloid wheels are respectively supported by the two eccentric circles on the crankshaft through a cycloid wheel support bearing to form a rotational support, and a plurality of pin matching holes are evenly distributed along the circumferential direction on the two cycloid wheels; the output disk is supported by the rear section of the crankshaft through the crank support bearing; a plurality of pin positioning holes are evenly distributed along the circumferential direction on the side of the output disk close to the cycloid wheel; the rear sections of the plurality of pins are respectively inserted and fixed in the plurality of pin positioning holes, and the front sections of the plurality of pins are respectively inserted into the plurality of pin matching holes on the two cycloid wheels to form a driving fit; The pin gear housing is sleeved on the outside of the two cycloid wheels and the output disc; the front section of the inner wall of the pin gear housing is evenly inlaid with a plurality of pin gear pins to form an annular pin gear group; the two cycloid wheels are internally meshed with the annular pin gear group; the rear section of the inner wall of the pin gear housing is supported by the output disc support bearing and the outer circle of the output disc to form a rotation support fit; The front end pressure plate and the rear end pressure plate are both annular pressure plates, which are fixedly mounted on the front end and the rear end of the pin gear housing respectively; External threaded holes connected to the motor of the transmission device or the frame of the electric power-assisted bicycle are evenly distributed along the circumferential direction on the front pressure plate; external threaded holes connected to the output actuator of the electric power-assisted bicycle are evenly distributed along the circumferential direction at the rear end of the output disk.

2. The transmission device for an electric power-assisted bicycle according to claim 1, characterized in that: A screw through hole is arranged at a position corresponding to each pin positioning hole on the output disk, and the screw through hole adopts a countersunk hole; the pin adopts a stepped pin shaft which is thick at the front and thin at the back, and a threaded hole is arranged at the center of the pin; a weight reduction hole is arranged at the front end of the threaded hole in the center of the pin; multiple pins are respectively inserted and matched with multiple pin positioning holes on the output disk through their respective rear sections, and the pins are fixed to the output disk through the threaded holes installed on the pins and the screws in the corresponding screw through holes on the output disk.

3. The transmission device for an electric power-assisted bicycle according to claim 1, characterized in that: The cycloid wheel is made of lightweight composite material.

4. The transmission device for an electric power-assisted bicycle according to claim 1, characterized in that: Weight-reducing holes are evenly distributed along the circumferential direction on the output disc.

Images