TWI667456B - Universal mount bicycle power meter module - Google Patents

Abstract

A universal mount for a bicycle power meter module has a base member having first and second ends and a narrow central portion that is relatively compressible in response to the applied force. A mounting nut that is internally threaded to match a hole in the first end is fixedly secured to the first end. The nut secures the first end of the base member to an externally threaded end of a bicycle shaft. The second end of the base member is constructed to be securely fastened to a rear frame portion of the bicycle by use of a mounting clip. A strain gauge sensor assembly is mounted to the central portion of the base member to produce a resistance value representative of the amount of compression within the central portion. The sensor assembly is coupled to a signal processing unit having circuitry for converting the resistance value into a bicycle hand power signal.

Description

Universal mount for bicycle power meter module

The present invention relates to a bicycle power meter for displaying the amount of power a bicycle rider spends during riding. More specifically, the present invention relates to a universal mount for a bicycle power meter module that can be mounted to any bicycle for generating an electronic signal that determines power.

Bicycle power meters are increasingly used by professional and amateur cyclists as an aid to developmental training. There are several different types of bicycle power meters available, some of which use strain gauges to measure the force that a cyclist applies to a crankset, bottom bracket or rear hub. While electronic signals representing the applied force can be effectively provided, conventional power meters using strain gauges are relatively expensive and somewhat difficult to install.

A bicycle power meter is disclosed in U.S. Patent No. 8,370,087, issued on February 5, 2013, which is assigned to the benefit of the benefit of the present disclosure. User lists are easy to install. The bicycle power meter has an end mounted on a front fork of the bicycle frame A strain gauge sensor assembly on a relatively compressible web portion. The relatively compressible web portion is adjacent the rear hub and receives the force applied by the cyclist to the crank set and transmitted to the hub through the chain and sprocket assembly. The sensor assembly has two ohmically interconnected stretch sensors, each stretch sensor having a first layer carrying a variable resistive element (the resistance of the variable resistive element follows the compressible belly The displacement of the plate portion is changed), and a second layer for supporting the first layer. The sensor assembly is coupled to two other resistors in a bridge circuit for generating a signal representative of the force applied by the cyclist. These signals are processed together with the speed signal to produce a power signal and the power signal is provided to a display. While the bicycle power meter overcomes the shortcomings of previously known bicycle power meters, its use is limited to bicycles having bicycles having relatively compressible web portions. Not all bicycle frames have this structure.

The present invention includes a universal mount for a bicycle power meter module that can be mounted to any bicycle having a rear axle and a rear frame portion with externally threaded ends. The universal mount of the bicycle power meter is relatively inexpensive and can effectively provide an electronic signal representative of the force applied by the cyclist, which can be combined with the speed signal to produce an instantaneous power measurement.

A first aspect of the invention includes a bicycle power meter module including an elongated base member having a first end with a bore and a second end that is designed to be secured to the rear axle of the bicycle Neighboring a bicycle frame portion, and a compressible central portion; a strain gauge sensor assembly mounted on the compressible central portion, the strain gauge sensor assembly having first and second extension sensors, Each of the stretching sensors includes a first layer having a variable resistance element mounted thereon and a second layer for supporting the first layer, the first and second extension sensors The variable resistive elements are ohmically interconnected to present a total resistance value representative of the strength of the cyclist; a mounting nut that is securely secured to the first end of the base member, the nut having a center a threaded perforation that mates with the bore of the first end of the base member such that the nut can be threadedly mounted to an associated externally threaded bicycle axle for positioning the base member a first end thereof is fixed to the bicycle axle; and a signal processing unit mounted on the base member and electrically coupled to the strain gauge sensor assembly for converting the total resistance value into a bicycle driver Power signal.

The compressible central portion of the base member preferably has a width that is less than the width of the first and second ends of the base member to facilitate compression of the central portion when a force is applied.

The second end of the base member is preferably secured to the bicycle frame member by a mounting clip secured to the second end of the base member, the mounting fixture having a mounting strap that is designed to secure Grab the bike frame portion firmly.

The first and second extension sensors are disposed in such a manner that each of the first layers faces each other or each of the second layers faces each other.

The signal processing unit preferably includes a bridge circuit having the first and second extension sensors connected in a first branch and a pair of fixed resistors connected in a second branch; an amplifier coupled to the bridge circuit for amplifying a signal representative of the total resistance value; and an analog-to-digital converter ) is coupled to the amplifier for converting the signal output from the amplifier into a digital signal; and a microcomputer coupled to the analog variable bit converter for receiving the digital signal and from the The speed signal of the associated bicycle speedometer converts the received signal into a power signal. In a preferred wireless embodiment, the signal processing unit further includes a transmitter coupled to the microcomputer for receiving power signals and generating equal wireless signals, and an antenna coupled to the transmitter The device is configured to broadcast the equal wireless signal to an associated receiver.

A second aspect of the invention includes a combination of a bicycle and a bicycle power meter module, the bicycle having a frame having a rear portion and a rear axle having a rear portion adjacent the frame Externally threaded end portion; the bicycle power meter module includes an elongated base member having a first end with a hole and a second end designed to be secured to a bicycle frame adjacent to the rear axle of the bicycle a portion, and a compressible central portion; a strain gauge sensor assembly mounted on the compressible central portion, the strain gauge sensor assembly having first and second extension sensors, each The extension sensor includes a first layer having a variable resistance element mounted thereon and a second layer for supporting the first layer, the first and second extension sensors The variable resistance elements are ohmically interconnected to present a total resistance value representative of the strength of the bicycle hand; a mounting nut that is securely secured to the first end of the base member, the nut having a central internal thread a perforation that mates with the aperture of the first end of the base member such that the nut can be threadedly mounted to an associated externally threaded bicycle axle for use in the base member a first end is fixed to the bicycle axle; and a signal processing unit mounted on the base member and electrically coupled to the strain gauge sensor assembly for converting the total resistance value into cyclist power Signal.

The compressible central portion of the base member preferably has a width that is less than the width of the first and second ends of the base member to facilitate compression of the central portion when a force is applied.

The second end of the base member is preferably secured to the bicycle frame member by a mounting clip secured to the second end of the base member, the mounting fixture having a mounting strap that is designed to secure Grab the bike frame portion firmly.

The first and second extension sensors are disposed in such a manner that each of the first layers faces each other or each of the second layers faces each other.

The signal processing unit preferably includes a bridge circuit having the first and second extension sensors connected in a first branch and a pair of fixed resistors connected in a second branch; an amplifier And coupled to the bridge circuit for amplifying a signal representing a total resistance value; a converter of analog-to-variable bits coupled to the amplifier for converting a signal output from the amplifier into a digital signal And a microcomputer coupled to the analog variable bit converter for receiving the digital signal and the speed signal from an associated bicycle speedometer and converting the received signal into a power signal. In a preferred wireless embodiment, the signal processing unit Further comprising a transmitter coupled to the microcomputer for receiving a power signal and generating an equal wireless signal; and an antenna coupled to the transmitter for broadcasting the equal wireless signal to a correlation Connected to the receiver.

The present invention significantly facilitates the assembly of a bicycle power meter to any bicycle having a rear axle and a rear frame portion having externally threaded ends. The bicycle power meter module can be easily secured to the components of the bicycle during manufacture. Similarly, the bicycle power meter module can be easily secured to the bicycle at any point in the distribution chain, such as at a retailer, as an additional option. The cyclist can also add the bicycle power meter module to the bicycle after purchasing the bicycle with relatively low cost and low effort.

For a fuller understanding of the nature and advantages of the invention, reference should be

10‧‧‧Bicycle Power Meter Module Assembly

11‧‧‧Pedestrian parts

12‧‧‧First end (right rear fork)

13‧‧‧second opposite end

14‧‧‧Central Part

15‧‧‧Strain gauge sensor assembly

17‧‧‧Circuit board

18‧‧‧Battery

19‧‧‧on/off switch

20‧‧‧ nuts

22‧‧‧Installation holes

23‧‧‧Installation holes

25‧‧‧Installation clip

26‧‧‧Installation holes

27‧‧‧Installation holes

28‧‧‧Threaded fasteners (shafts)

29‧‧‧ Frame part

31‧‧‧Installation belt

40‧‧‧ stretching sensor

42‧‧‧ first floor

43‧‧‧Variable resistance components

44‧‧‧ second base

40a‧‧‧ stretching sensor

40b‧‧‧ stretching sensor

42a‧‧‧ first floor

42b‧‧‧ first floor

44a‧‧‧ second floor

44b‧‧‧ second floor

50‧‧‧Strain gauge sensor assembly

52‧‧‧Fixed resistor

54‧‧‧Fixed resistance

55‧‧‧Amplifier

56‧‧‧ analog variable bit converter

58‧‧‧Microcomputer

60‧‧‧Multi-function display

64‧‧‧ Receiver

62‧‧‧transmitters

63‧‧‧Antenna

36‧‧‧Sprocket teeth

35‧‧‧Drive chain

1 is a plan view of a preferred embodiment of a bicycle power meter module incorporating the present invention; and FIG. 2 is a partial plan view of the sprocket side of the bicycle, showing the bicycle of FIG. 1 mounted on the positioning Power meter module; FIG. 3 is an enlarged cross-sectional view taken along line 3-3 of FIG. 2, illustrating the fixed nut, frame and module base assembly; FIG. 4 is along the FIG. Amplified profile taken by line 4-4 Figure, which illustrates a mounting clip assembled to the bicycle frame; Figure 5 is a block diagram of a bicycle power meter module using a single strain gauge sensor assembly constructed as a wired unit; Figure 6 is a bicycle A block diagram of a power meter module using a single strain gauge sensor assembly constructed as a wireless unit; Figure 7 is a schematic illustration of a single strain gauge sensor illustrating the sensor in three different positions 8 is a schematic view of a first embodiment of a two-element strain sensor assembly; FIG. 9 is a schematic view of a second embodiment of a two-element strain sensor assembly; and FIG. 10 is a diagram illustrating cyclist power related to a crankset angle A schematic diagram of the change in position.

Turning now to the drawings, Figure 1 is a plan view of a first embodiment of a bicycle power meter module incorporating the present invention. As seen in the figures, a bicycle power meter module assembly, generally designated 10, includes an elongated base member 11 having a first end portion 12, a second opposite end portion 13, and a central portion. Portion 14, which preferably has a narrower width than ends 12, 13. The elongated base member 11 is formed of a relatively compressible thin metal (e.g., stainless steel) having a thickness of 1.0 mm to allow the length to be contracted or extended in response to the force applied to the end portion 12.

A strain gauge assembly 15 is secured to the central portion 14 The upper surface, which will be described more fully below with reference to Figures 7-9. The strain gauge assembly 15 has a pair of ohmic conductors that are electrically connected to an input terminal of a signal processing unit that is attached to a circuit board 17, which will be described below with reference to Figure 5 (wired version) and Figure 6 (wireless version). For a more complete description, the circuit board 17 is bonded to the upper surface of the end portion 13 of the base member 11. The signal processing unit is powered by a small battery 18 that is removably secured to the circuit board 17 (as shown) or directly to the upper surface of the end portion 13 of the base member 11. Power from the battery 18 to the signal processing unit is controlled by a manually operated on/off switch 19.

An internally threaded nut 20 is secured to the upper surface of the first end portion 12 of the base member 11, and a nut is used to secure the bicycle's power meter module 10 to one end of the bicycle's rear axle. The nut 20 can be secured by a variety of techniques, such as welding, brazing, or bonding with a strong adhesive. It is important that the fixed process is that the nut 20 must be firmly fixed to the base member 11 such that relative movement between the nut 20 and the base member 11 is prevented. In other words, when the end portion of the bicycle axle on which the nut 20 is screwed is deflected due to the force applied by the bicycle chain, the deflection must be transmitted to the base member 11 via the nut 20. The strain gauge assembly 15 senses the amount of deflection.

The second opposite end portion 13 of the base member 11 is provided with a pair of mounting holes 22, 23. A mounting clip (preferably a car hose clamp), generally designated 25, is provided with a pair of mating mounting holes 26, 27 such that the end portion 13 can be shown in Figures 2 and 4. the way It is fixed to the mounting clip 25.

2 is a partial plan view, as seen from the rear sprocket of the bicycle, showing the bicycle power meter module 10 of FIG. 1 mounted in position. Referring to this figure and Figures 3 and 4, the mounting clip 25 is first secured to the opposite end 13 of the base member 11 by passing the threaded fastener 28 through the holes 22, 23, 26, 27. Next, the module 10 is screwed to the end of the shaft 28 in the manner shown in FIG. 2 until the base member 11 is firmly fixed to the positioning (where the opposite end is 13 is aligned with the portion 29 of the bicycle frame and attached to the sprocket end of a threaded shaft 28. Next, the mounting strap 31 of the mounting clip 25 is wound around the frame portion 29 and the mounting strap 31 is fastened to the periphery of the frame portion 29 until the opposite end portion 13 is firmly fixed to The frame portion 29 is affixed to the opposite end portion 13 of the base member 11 to the frame portion 29 of the bicycle frame. This completes the mechanical mounting of the bicycle power meter module 10.

In use, when a cyclist applies force to the pedal attached to the crankset, the drive chain 35 (Fig. 2) is subjected to a force transmitted through the sprocket teeth 36 to the axle 28, causing the axle 28 Skewed in the horizontal direction. This deflection of the shaft 28 is transmitted through the base member 11 to the strain gauge assembly 15, causing a change in the signal output from the strain gauge assembly 15. The output signal is processed in a manner described below to produce a power level signal that can be displayed to the cyclist.

Figure 7 illustrates a simple extension sensor 40 having an ohmic resistance that changes with the linear longitudinal displacement of the sensor body. The characteristics of the measured quantity. The stretch sensor 40 has a first layer 42 having a thin variable resistance element 43 mounted thereon and a second base layer 44 that carries the first layer and provides additional mechanical strength to the sensor 40. The resistance value of the sensor 40 depends on the longitudinal displacement of the sensor body. As shown in FIG. 7, when the sensor 40 is displaced in one direction in a first direction (the deflection is shown in the figure), the value of the resistor is increased (R+r), where R is The resistance value of the sensor 40 when it is stationary and r is the additional resistance value due to the displacement in the first direction. Similarly, when the sensor 40 is displaced in the opposite direction, the value of the resistance decreases (R-r).

Figure 8 illustrates the type of strain gauge sensor assembly 15 included in the power meter configuration shown in Figures 1 and 2. As shown in this figure, the sensor assembly 15 includes two double layer extension sensors 40a, 40b having a first layer 42a, 42b and a second layer 44a, 44b. The stretch sensors 40a, 40b are arranged in a relative relationship of the first layers 42a, 42b in a relationship of (R + r), (R - r). When the force applied to the shaft 28 of the right rear fork 12 is displaced by the sensor assembly 15, the total resistance of each stretch sensor will change equally in the opposite direction.

FIG. 9 illustrates another type of strain gauge sensor assembly 50 included in the power meter configuration shown in FIGS. 1 and 2. As seen in this figure, the sensor assembly 50 includes two double layer extension sensors 40a, 40b having a first layer 42a, 42b and a second layer 44a, 44b. The stretching sensors 40a, 40b are arranged in a relative relationship of the second layers 44a, 44b in a relationship of (R - r), (R + r). When the force applied to the shaft 28 of the right rear fork 12 is displaced by the sensor assembly 50, each of the stretch sensors The total resistance will change equally in the opposite direction.

Figure 5 is a block diagram of a bicycle power meter unit using a single strain gauge sensor assembly constructed to form a wired unit. As seen in this figure, the stretch sensors 40a, 40b including the strain gauge sensor assembly 15 or 50 are coupled to a pair of fixed resistors 52, 54 in a conventional Wheatstone bridge circuit configuration. The upper node of the bridge is connected to the source provided by the battery 18 to the potential Vc. The lower node of the bridge is connected to the circuit ground. The node on the right is connected to one end of the fixed resistors 52, 54 and serves as an output terminal of the bridge circuit. The second end of the fixed resistor 52 is connected to one end of the extension sensor 40a and is connected to the supply voltage Vc. The second end of the fixed resistor 54 is coupled to one end of the stretch sensor 40b and to the ground of the circuit. The other ends of the stretch sensors 40a, 40b are connected together and serve as another output terminal of the bridge circuit.

The output terminals of the bridge circuits are coupled to the input terminals of an amplifier 55 at which the bridge signals are amplified. Amplifier 55 is preferably a MAX4197 type unit available from MAXIM Corporation. The amplified signal output from amplifier 55 is coupled to an input of analog variable bit converter 56, which converts the amplified analog signal into equal digital signals. The digital signal output from the analog variable bit converter 56 is coupled to the input port of a microcomputer 58. The analog-to-digital converter 56 and microcomputer 58 are preferably combined into a PIC 10F202 unit available from Microchip. A speed signal from a bicycle speedometer (not shown) is also coupled to the microcomputer 58. Microcomputer 58 processes the power and speed signals using known algorithms to provide power size signals. High power The small signal is coupled to a multi-function display 60 that displays the current power value in a bicycle readable form. In the embodiment of Figure 5, the units are coupled together by ohmic connection wires.

6 is a block diagram of a bicycle power meter unit constructed using a single strain gauge sensor assembly that forms a wireless unit. In this figure, elements corresponding to the same elements in the system of Fig. 5 are denoted by the same reference numerals. In the system of Figure 6, the processed power signal is coupled to an input of a r.f. transmitter 62 on circuit board 17. Transmitter 62 is preferably of the type nRF24AP2 ANT+ module available from Nordisk Semiconductor, Norway. Transmitter 62 transmits a power signal through an antenna 63 (Fig. 1) to a receiver 64 adjacent to the multifunction display 60, which provides the signals to the multifunction display 60.

In both the wired and wireless versions of the bicycle power meter unit, the strain gauge assembly 15, 50, amplifier 55, A/D converter 56, microcomputer 58, and transmitter 62 are all mounted on the circuit board 17; Display 60 and receiver 64 are then mounted at a location convenient for the cyclist to view the display, typically somewhere on the faucet handle of the bicycle.

In use, when the cyclist applies power to the bicycle pedal, the magnitude of the force is monitored by the bridge circuit and converted into a visually viewable power display signal for viewing by the cyclist. Figure 10 is a schematic diagram showing the power of the cyclist as a function of the angular position of the crankset. At position (a), the pedal is substantially horizontal and the cyclist is applying maximum force with the front pedal. At position (b), the pedal is substantially vertical and self The driver is applying the least amount of power. At position (c), the pedal is again substantially horizontal and the cyclist is applying maximum force with the front pedal; at position (d), the pedal is again substantially vertical and the cyclist is applying minimal force.

It will now be apparent that bicycle power meter modules made in accordance with the teachings of the present invention provide advantages over conventional bicycle power meters that use strain gauges in terms of cost and ease of installation. More specifically, the bicycle power meter module 10 is relatively easy to mount to any end having a threaded rear axle (on which the nut 20 can be threaded) and a rear frame portion (mounting strap 31 of the mounting clip 25) On a bicycle that can be attached to it). This installation can be done at the bicycle factory or elsewhere in the transaction chain (eg, by a retailer or user-cyclist). In addition, the bicycle power meter module manufactured in accordance with the teachings of the present invention can be constructed in a wired or wireless mode, which provides great flexibility in the mounting process.

Although the present invention has been described with reference to the specific embodiments thereof, many modifications, alternative structures and equivalents may be made without departing from the spirit of the invention. For example, while certain circuit components have been disclosed, other equivalent units can be used as needed. Therefore, the above description should not be taken as limiting the invention, and the scope of the invention is defined by the scope of the appended claims.

Claims (14)

A bicycle power meter module includes: an elongated base member having a first end with a hole and a second end designed to be secured to a bicycle frame portion adjacent to the rear axle of the bicycle, and a a compressible central portion; a strain gauge sensor assembly mounted on the compressible central portion, the strain gauge sensor assembly having first and second extension sensors, each extension sensor A first layer having a variable resistance element mounted thereon and a second layer for supporting the first layer, the variable resistance element of the first and second extension sensors being Omically interconnected to present a total resistance value representative of the strength of the cyclist; a mounting nut that is securely secured to the first end of the base member, the nut having a threaded perforation in the center Matching the bore such that the nut can be threadedly mounted to an associated externally threaded bicycle axle for securing the base member to the bicycle axle at a first end thereof; a signal processing unit mounted on the base member It is electrically coupled to the strain gage sensor assembly, as well as for the total resistance value of the power signal into the cyclist bicycle speed signal from the bicycle speed even an associated meter. The bicycle power meter module of claim 1, wherein the compressible central portion of the base member has a width that is smaller than a width of the first and second ends of the base member to facilitate the central portion. Compression when force is applied. The bicycle power meter module of claim 1, further comprising a mounting clip fixed to the second end of the base member, the mounting fixture having a mounting strap designed to firmly grasp the Bicycle frame section. The bicycle power meter module of claim 1, wherein the first and second extension sensors are disposed in such a manner that each of the first layers faces each other. The bicycle power meter module of claim 1, wherein the first and second extension sensors are disposed in such a manner that each of the second layers faces each other. The bicycle power meter module of claim 1, wherein the signal processing unit comprises a bridge circuit having the first and second extension sensors and a pair of connections connected in a first branch a fixed resistor in a second branch; an amplifier coupled to the bridge circuit for amplifying a signal representative of the total resistance value; an analog-to-digital converter Coupled to the amplifier for converting a signal output from the amplifier into a digital signal; and a microcomputer coupled to the analog variable bit converter for receiving the digital signal and from an associated The speed signal of the bicycle speedometer converts the received signal into a power signal. The bicycle power meter module of claim 6, further comprising a transmitter coupled to the microcomputer for receiving a power signal and generating an equal wireless signal; and an antenna coupled to the antenna A transmitter for broadcasting the equal wireless signal to an associated receiver. A bicycle comprising: a frame having a rear portion and a rear axle having an externally threaded end adjacent the rear portion of the frame; a bicycle power meter module including an elongated base member having a first end having a hole, a second end secured to the rear portion of the frame, and a compressible central portion; a strain gauge sensor assembly mounted to the compressible central portion The strain gauge sensor assembly has first and second extension sensors, each extension sensor including a first layer having a variable resistance element mounted thereon and a support a second layer of the first layer, the variable resistance elements of the first and second extension sensors are ohmically interconnected to present a total resistance value representative of the strength of the cyclist; a mounting nut that is firmly secured Securely secured to the first end of the base member, the nut having a threaded perforation in the center that mates with the bore, the nut being threadably mounted to the end of the externally threaded axle Reinforcing the base member to the bicycle axle end at its first end; a signal processing unit mounted on the base member and electrically coupled to the strain gauge sensor assembly for converting the total resistance value and the bicycle speed signal from an associated bicycle speedometer into a bicycle Hand power signal. The bicycle of claim 8 wherein the compressible central portion of the base member has a width that is less than a width of the first and second ends of the base member to facilitate application of the central portion. Time compression. The bicycle of claim 8 further comprising a mounting clip fixed to the second end of the base member, the mounting fixture having an installation The belt is designed to firmly grasp the rear of the bicycle frame. A bicycle according to claim 8 wherein the first and second extension sensors are disposed in such a manner that each of the first layers faces each other. A bicycle according to claim 8 wherein the first and second extension sensors are disposed in such a manner that each of the second layers faces each other. The bicycle of claim 8 wherein the signal processing unit further comprises a bridge circuit having the first and second extension sensors connected in a first branch and a pair connected a fixed resistor in the two branches; an amplifier coupled to the bridge circuit for amplifying a signal representative of the total resistance value; and an analog-to-digital converter coupled to the amplifier for The signal output of the amplifier is converted into a digital signal; and a microcomputer coupled to the analog variable bit converter for receiving the digital signal and the speed signal from an associated bicycle speedometer and receiving the signal The signal is converted into a power signal. The bicycle of claim 13 further comprising a transmitter coupled to the microcomputer for receiving a power signal and generating an equal wireless signal; and an antenna coupled to the transmitter for use The equal wireless signal is broadcast to an associated receiver.