A new crank assembly for a sports bicycle

Abstract

The utility model relates to a new crank assembly suitable for sports bicycle, including mandrel, the centre hole is established in the middle part of mandrel, circuit module is installed with the cooperation of mounting sleeve in the centre hole, the inner wall surface of centre hole is pasted with strain gauge, strain gauge and circuit module electricity is connected, the both ends of mandrel are installed with first crank arm and second crank arm respectively, and the pedaling force of rider is converted into the rotary motion of mandrel through first crank arm and second crank arm, and the mandrel that rotates produces the torque, makes strain gauge produce deformation to gather the deformation of strain gauge through circuit module, and then obtains the power parameter of mandrel rotation process. Through setting up mandrel, mounting sleeve, strain gauge and circuit module, thereby need not using power meter, can effectively reduce the production manufacturing cost, also can obtain accurate data under the bumpy road condition.

Description

Technical Field

[0001] This utility model relates to the field of sports bicycle technology, and in particular to a novel crank assembly suitable for sports bicycles. Background Technology

[0002] As cycling has expanded from a basic mode of transportation to competitive, fitness, and leisure activities, the sports bicycle industry has developed a product matrix centered on road bikes, mountain bikes, and leisure bikes, encompassing hybrid bikes, downhill bikes, folding bikes, and other subcategories. These models, through differentiated designs, meet the diverse needs of users and drive the industry towards lightweighting and integration.

[0003] In existing technologies, the crank assembly of a cycling bicycle typically incorporates a power meter to collect real-time energy output data such as power output, cadence, and percentage of force exerted by each leg during riding, providing users with precise training guidance and performance evaluation. However, the existing architecture of the crank assembly incorporating a power meter has the following problems:

[0004] (1) In order to accommodate the installation of the power meter, the crank assembly spindle needs to be a custom stepped shaft, which increases its structural complexity and production cost.

[0005] (2) Power meters are expensive to purchase and have a complex structure. At the same time, they have high requirements for the riding environment. When faced with bumpy road conditions, the accuracy of the data they collect decreases.

[0006] (3) Existing power meters have poor waterproof performance, with a waterproof failure rate of over 12%. Utility Model Content

[0007] Therefore, it is necessary to provide a new type of crank assembly suitable for sports bicycles, addressing the problems of high production, manufacturing, and procurement costs, poor environmental adaptability, and poor waterproofing of existing crank assemblies.

[0008] The technical solution adopted in this utility model is as follows:

[0009] A novel crank assembly for sports bicycles includes a spindle with a central hole in the middle. A circuit module is installed in the central hole through a mounting sleeve. A strain gauge is attached to the inner wall of the central hole and is electrically connected to the circuit module.

[0010] The mandrel is equipped with a first crank arm and a second crank arm at its two ends, respectively. The first and second crank arms convert the rider's pedaling force into the rotational motion of the mandrel. The rotating mandrel generates torque, which causes the strain gauge to deform. The deformation of the strain gauge is collected by the circuit module, thereby obtaining the power parameters of the mandrel rotation process.

[0011] As a further improvement to the above technical solution:

[0012] The outer circumferential surfaces at both ends of the mandrel are respectively provided with a first external spline and a second external spline, wherein the number of teeth of the first external spline is greater than the number of teeth of the second external spline.

[0013] The first crank arm has a first mounting hole at its end, and a first internal spline is provided on the inner wall of the first mounting hole. The first internal spline and the first external spline are connected by a press-fit method.

[0014] A first end cap is fitted into the first mounting hole.

[0015] The end of the second crank arm is provided with a second mounting hole, and the inner wall of the second mounting hole is provided with a second internal spline. The second internal spline and the second external spline are connected by a sliding connection.

[0016] An internal thread is provided on the inner wall of one end of the central hole. The spindle is installed by engaging with the second end cap through the internal thread, thereby locking the second crank arm onto the spindle through the second end cap.

[0017] The structure of the mounting sleeve is as follows: it includes a hollow sleeve body, and a partition is provided inside the sleeve body to separate a first accommodating cavity for accommodating the battery and a second accommodating cavity for accommodating the circuit module.

[0018] The inner wall of the second accommodating cavity is provided with a limiting groove for limiting the position of the circuit module.

[0019] An I-shaped mounting pad is arranged between the strain gauge and the mandrel.

[0020] When the outer diameter of the mandrel is 24mm, the distance between the bonding position of the strain gauge and the end of the mandrel along the axial direction of the mandrel is 35mm ± 0.5mm.

[0021] When the outer diameter of the mandrel is 29mm, the distance between the bonding position of the strain gauge and the end of the mandrel along the axial direction of the mandrel is 40mm±0.5mm.

[0022] When the outer diameter of the mandrel is 30mm, the distance between the bonding position of the strain gauge and the end of the mandrel along the axial direction of the mandrel is 45mm ± 0.5mm.

[0023] The inner wall of the central hole is treated with sandblasting.

[0024] The circuit module includes a circuit board on which a gain amplifier and an analog-to-digital converter are soldered.

[0025] The beneficial effects of this utility model are as follows:

[0026] This utility model has a compact and reasonable structure and is easy to operate. By setting a mandrel, mounting sleeve, strain gauge and circuit module, it can obtain the power parameters of the mandrel rotation process based on the deformation of the strain gauge, so that there is no need to use a power meter. It can effectively reduce the production and manufacturing cost, reduce the requirements of the riding environment, and obtain accurate data even on bumpy roads.

[0027] This utility model also has the following advantages:

[0028] (1) By setting the first end cap and the second end cap, the center hole of the mandrel can be sealed, thereby preventing the internal circuit modules and strain gauges from getting damp, ensuring the accuracy of the results, and improving the waterproof performance of the components.

[0029] (2) By setting a second external spline with fewer teeth and a corresponding second internal spline, a quick-release fit between the second crank arm and the spindle can be achieved, which makes it convenient to assemble and replace the second crank arm.

[0030] (3) The mandrel is cylindrical in shape, which is easy to process and can reduce production and manufacturing costs.

[0031] (4) By setting a hollowed-out part on the mounting sleeve, the weight of the mounting sleeve can be effectively reduced, and the heat dissipation performance of the circuit module can be improved.

[0032] (5) By setting up mounting pads, it can be ensured that the adhesive layer used to bond the strain gauges is uniform and of appropriate thickness, thereby reducing stress transmission errors and ensuring measurement results. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of this utility model.

[0034] Figure 2 This is an exploded view of the present invention.

[0035] Figure 3 This is a top view of the mandrel in this utility model.

[0036] Figure 4 for Figure 3 A sectional view of section AA in the middle.

[0037] Figure 5 This is a schematic diagram of the structure of the mounting sleeve in this utility model. Figure 1 .

[0038] Figure 6 This is a schematic diagram of the structure of the mounting sleeve in this utility model. Figure 2 .

[0039] Wherein: 1. First crank arm; 2. Second crank arm; 3. Spindle; 4. First end cap; 5. Second end cap; 6. Mounting sleeve; 7. Mounting pad; 8. Circuit module; 9. First external spline; 10. Second external spline;

[0040] 601. Sleeve body; 602. Partition plate; 603. First receiving cavity; 604. Second receiving cavity; 605. Limiting groove; 606. Limiting step. Detailed Implementation

[0041] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0042] The structure and function of this utility model are as follows:

[0043] like Figures 1-6 As shown, a novel crank assembly for a sports bicycle includes a spindle 3 with a central hole in its middle. A circuit module 8 is mounted inside the central hole via a mounting sleeve 6. Strain gauges are attached to the inner wall of the central hole and are electrically connected to the circuit module 8. A first crank arm 1 and a second crank arm 2 are mounted at both ends of the spindle 3. The first and second crank arms 1 and 2 convert the rider's pedaling force into rotational motion of the spindle 3. The rotating spindle 3 generates torque, causing the strain gauges to deform. The circuit module 8 collects the deformation of the strain gauges, thereby obtaining the power parameters during the rotation of the spindle 3. By using the spindle 3, mounting sleeve 6, strain gauges, and circuit module 8, a power meter is unnecessary, effectively reducing manufacturing costs. Furthermore, the strain gauges and circuit module 8 have strong anti-interference capabilities, enabling accurate data acquisition even on bumpy roads.

[0044] The outer circumferential surfaces at both ends of the spindle 3 are respectively provided with a first external spline 9 and a second external spline 10, the number of teeth of the first external spline 9 being greater than the number of teeth of the second external spline 10. The spindle 3 is installed with the first crank arm 1 and the second crank arm 2 respectively through the first external spline 9 and the second external spline 10.

[0045] The first crank arm 1 has a first mounting hole at its end. A first internal spline is provided on the inner wall of the first mounting hole. The first internal spline and the first external spline 9 are connected by a press-fit method. The first internal spline and the first external spline 9 have a relatively dense number of teeth to achieve a tight fit between the first mounting hole and the outer circumferential surface of the spindle 3, thereby fixing the first crank arm 1 to the spindle 3.

[0046] A first end cap 4 is installed at the first mounting hole. The first end cap 4 is bonded to the first mounting hole with adhesive and covers the first mounting hole, thereby preventing external moisture and dust from entering the spindle 3 through the first mounting hole.

[0047] The end of the second crank arm 2 is provided with a second mounting hole, and the inner wall of the second mounting hole is provided with a second internal spline. The second internal spline and the second external spline 10 are connected by a sliding connection. By setting the second external spline 10 with fewer teeth and the corresponding second internal spline, the quick-release engagement between the second crank arm 2 and the spindle 3 can be realized, thereby facilitating the assembly and replacement of the second crank arm 2.

[0048] An internal thread is provided on the inner wall of one end of the center hole. The spindle 3 is installed by engaging with the second end cover 5 through the internal thread, thereby locking the second crank arm 2 onto the spindle 3 through the second end cover 5. A protrusion is provided in the middle of the second end cover 5. An external thread is provided on the outer circumference of the protrusion. The protrusion passes through the second mounting hole and extends into the center hole. The connection between the protrusion and the center hole is made by thread. After installation, the second end cover 5 can cover the second mounting hole, thereby covering the center hole and preventing external moisture and dust from entering the spindle 3 through the first mounting hole.

[0049] By setting the first end cap 4 and the second end cap 5, the center hole of the mandrel 3 can be sealed, thereby preventing the internal circuit module 8 and strain gauge from getting damp, ensuring the accuracy of the results, and improving the waterproof performance of the component.

[0050] like Figures 5-6 As shown, the structure of the mounting sleeve 6 is as follows: it includes a hollow sleeve body 601, and a partition 602 is provided inside the sleeve body 601, thereby dividing the sleeve body 601 into a first accommodating cavity 603 for accommodating the battery and a second accommodating cavity 604 for accommodating the circuit module 8; a limiting groove 605 is provided on the inner wall surface of the second accommodating cavity 604 to limit the circuit module 8. The limiting groove 605 is used to limit the circuit board of the circuit module 8, and the battery is used to power the circuit module 8.

[0051] In this invention, the mounting sleeve 6 is also provided with an outwardly protruding limiting step 606, which can cooperate with the limiting groove 605 to support and limit the circuit board, effectively improving the installation stability of the circuit board.

[0052] An I-shaped mounting plate 7 is arranged between the strain gauge and the mandrel 3. By setting the mounting plate 7, it is possible to ensure that the adhesive layer used to attach the strain gauge is uniform and of appropriate thickness, thereby reducing stress transmission errors and ensuring measurement results.

[0053] When the outer diameter of mandrel 3 is 24mm, the distance between the bonding position of the strain gauge and the end of mandrel 3 along the axial direction is 35mm ± 0.5mm; when the outer diameter of mandrel 3 is 29mm, the distance between the bonding position of the strain gauge and the end of mandrel 3 along the axial direction is 40mm ± 0.5mm; and when the outer diameter of mandrel 3 is 30mm, the distance between the bonding position of the strain gauge and the end of mandrel 3 along the axial direction is 45mm ± 0.5mm. By rationally arranging the bonding positions of the strain gauges, the strain-to-voltage conversion efficiency can be improved. At the same time, stress concentration areas and vibration nodes can be avoided, noise can be reduced, and the reliability and accuracy of the results can be improved.

[0054] The inner wall of the central hole is sandblasted to improve its surface roughness, thereby improving its adhesion to the mounting pad 7.

[0055] Circuit module 8 includes a circuit board on which a gain amplifier and an analog-to-digital converter are soldered. The gain amplifier amplifies the voltage signal input from the strain gauge, and the analog-to-digital converter converts the analog voltage signal into a digital voltage signal. Based on the ANT+ or BLE protocol, the digital voltage signal is transmitted to the central control system of the sports bicycle. The central control system performs calculations to obtain the power parameters of the spindle 3 during rotation.

[0056] In addition, circuit module 8 is also equipped with a filter to remove interference signals.

[0057] The working process of this utility model is as follows:

[0058] When in use, pedals are installed on the first crank arm 1 and the second crank arm 2, and a sprocket drive assembly is installed between the outer circumference of the spindle 3 and the wheel.

[0059] The rider pedals, which causes the first crank arm 1 and the second crank arm 2 to rotate, thereby causing the spindle 3 to rotate, which in turn drives the wheel to rotate through the chain drive assembly, thus enabling riding.

[0060] During the rider's ride, the rotating spindle 3 generates torque, causing the strain gauge to deform. The deformation of the strain gauge is collected by the circuit module 8, and the deformation signal is processed and transmitted to the central control system. The central control system performs calculations to obtain the power parameters of the spindle 3 rotation process.

[0061] Based on the crank assembly of this utility model, the power parameters that can be obtained include: the power of the first crank arm 1 (P_left), the power of the second crank arm 2 (P_right), and the total power P_total.

[0062] The calculation formulas for the above three power parameters based on the torque τ generated by the spindle 3 during rotation are as follows:

[0063] The power of the first crank arm 1 (P_left) = torque × angular velocity of the first crank arm 1 (ω_left)

[0064] The power (P_right) of the second crank arm 2 = torque × angular velocity (ω_right) of the second crank arm 2

[0065] Total power P_total = P_left + P_right

[0066] The torque τ generated by the spindle 3 during rotation, and the deformation ε generated by the strain gauge, are derived from the following formula:

[0067]

[0068] In the above formula, E represents the elastic modulus of the mandrel 3.

[0069] d represents the diameter of mandrel 3;

[0070] ε represents the strain of the strain gauge;

[0071] ν represents the Poisson's ratio of mandrel 3;

[0072] R represents the radius of the strain gauge attachment location;

[0073] K represents the calibration coefficient, which is a constant. In this invention, it is taken as 0.98-1.02.

[0074] The above description is an explanation of the present utility model and not a limitation thereof. The scope of the present utility model is defined by the claims. Within the protection scope of the present utility model, any form of modification may be made.

Claims

1. A novel crank assembly suitable for sports bicycles, characterized in that: Includes a mandrel (3), with a central hole in the middle of the mandrel (3), and a circuit module (8) is installed in the central hole through a mounting sleeve (6). A strain gauge is attached to the inner wall of the central hole, and the strain gauge is electrically connected to the circuit module (8). The mandrel (3) is equipped with a first crank arm (1) and a second crank arm (2) at its two ends respectively. The pedaling force of the rider is converted into the rotational motion of the mandrel (3) through the first crank arm (1) and the second crank arm (2). The rotating mandrel (3) generates torque, which causes the strain gauge to deform. The deformation of the strain gauge is collected by the circuit module (8), and then the power parameters of the rotation process of the mandrel (3) are obtained.

2. A novel crank assembly for a sports bicycle as described in claim 1, characterized in that: The outer circumferential surfaces at both ends of the mandrel (3) are respectively provided with a first external spline (9) and a second external spline (10), wherein the number of teeth of the first external spline (9) is greater than the number of teeth of the second external spline (10).

3. A novel crank assembly for a sports bicycle as described in claim 2, characterized in that: The first crank arm (1) has a first mounting hole at its end, and a first internal spline is provided on the inner wall of the first mounting hole. The first internal spline and the first external spline (9) are connected by a press-fit method.

4. A novel crank assembly for a sports bicycle as described in claim 3, characterized in that: A first end cap (4) is fitted into the first mounting hole.

5. A novel crank assembly for a sports bicycle as described in claim 2, characterized in that: The end of the second crank arm (2) is provided with a second mounting hole, and the inner wall of the second mounting hole is provided with a second internal spline. The second internal spline and the second external spline (10) are connected by a sliding connection. An internal thread is provided on the inner wall of one end of the central hole. The spindle (3) is installed by engaging with the second end cover (5) through the internal thread, thereby locking the second crank arm (2) onto the spindle (3) through the second end cover (5).

6. A novel crank assembly for a sports bicycle as described in claim 1, characterized in that: The structure of the mounting sleeve (6) is as follows: it includes a hollow sleeve body (601), and a partition (602) is provided inside the sleeve body (601), thereby dividing the sleeve body (601) into a first accommodating cavity (603) for accommodating the battery and a second accommodating cavity (604) for accommodating the circuit module (8). The inner wall of the second accommodating cavity (604) is provided with a limiting groove (605) for limiting the circuit module (8).

7. A novel crank assembly for a sports bicycle as described in claim 1, characterized in that: An I-shaped mounting pad (7) is arranged between the strain gauge and the mandrel (3).

8. A novel crank assembly for a sports bicycle as described in claim 1, characterized in that: When the outer diameter of the mandrel (3) is 24mm, the distance between the bonding position of the strain gauge and the end of the mandrel (3) along the axial direction of the mandrel (3) is 35mm ± 0.5mm. When the outer diameter of the mandrel (3) is 29mm, the distance between the bonding position of the strain gauge and the end of the mandrel (3) along the axial direction of the mandrel (3) is 40mm ± 0.5mm. When the outer diameter of the mandrel (3) is 30mm, the distance between the bonding position of the strain gauge and the end of the mandrel (3) along the axial direction of the mandrel (3) is 45mm ± 0.5mm.

9. A novel crank assembly for a sports bicycle as described in claim 1, characterized in that: The inner wall of the central hole is treated with sandblasting.

10. A novel crank assembly for a sports bicycle as described in claim 1, characterized in that: The circuit module (8) includes a circuit board on which a gain amplifier and an analog-to-digital converter are soldered.

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