JP5855532B2 - Bicycle frame shape - Google Patents

Description

  The present invention includes a top tube and a down tube extending rearward from the head pipe, a seat tube connecting between rear ends of the tubes, and extending from the connecting portion between the top tube and the seat tube to a lower rear portion, The present invention relates to a bicycle frame shape including a seat stay connected to a rear end portion of a chain stay extending rearward from a connection portion between the tube and the seat tube.

  Conventionally, as a bicycle frame, a diamond frame is composed of a top tube and a down tube extending rearward from the head pipe and a seat tube connecting between the rear ends of these tubes, and adapted to the leg output of the occupant. Since rigidity is required, a frame having high rigidity is adopted. In order to obtain rigidity adapted to the top athlete, efforts have been made to increase the lateral rigidity of the vehicle body parallel to the road surface. For example, a pipe having an inverted triangular cross section that is wide in the horizontal direction is adopted as the top tube to increase the rigidity in the horizontal direction, or there is a body frame feature disclosed for a bicycle described in Patent Document 1 below. was suggested.

  The bicycle disclosed in Patent Document 1 will be described with reference to FIG. 7. A vehicle body frame 101, a top tube 101 t and a down tube 101 d extending rearward from the head pipe 101 h, respectively, and a seat tube connecting these rear ends. 101s is a diamond frame, and in a bicycle supporting a bottom bracket 107 on which a pedal crank is pivotally supported at a connecting portion between the down tube 101d and the seat tube 101s, the top tube 101t, the down tube 101d, and the seat tube 101s At least one of the tubes is composed of a tube whose overall length is a laterally flat cross section.

Japanese Patent Laid-Open No. 5-170162 (see abstracts, etc.)

  In the bicycle frame shape described in Patent Document 1 described above, as the body frame 101, a top tube 101t and a down tube 101d extending rearward from the head pipe 101h, respectively, and a seat tube 101s connecting these rear ends are provided. The diamond frame is constructed to maintain the frame characteristics with high longitudinal rigidity of the vehicle body perpendicular to the road surface, and at least one of the top tube 101t, the down tube 101d, and the seat tube 101s has a laterally flat cross section. By configuring the tube (refer to the AA, BB, CC, DD, EE, and FF cross-sectional views in FIG. 7), only by changing the cross-sectional shape of the tube, The lateral rigidity of the vehicle body parallel to the road surface without causing any significant increase in frame weight Therefore, even when a large pedaling force is applied to the pedal, as used by top athletes, it is possible to effectively prevent lateral deflection of the frame and improve the pedaling force transmission efficiency. It became.

  However, in a competition bicycle used by top athletes and the like, further improvement in frame rigidity is required during pedaling. Moreover, in such a world-level competition, a shape that takes into account rectification effects such as air resistance of the vehicle body as much as possible is required.

  Therefore, in the present invention, the problem of the conventional competition bicycle frame shape is solved, it can withstand the pedaling high pedaling force, and the high rigidity is maintained while maintaining the rectifying function, and the rigidity of the connection intersection of the frame is also ensured. An object of the present invention is to provide a bicycle frame shape that can be improved and can reduce interference with the knee during pedaling.

For this reason, the present invention provides a top tube extending rearward from the head pipe, a down tube extending rearwardly, a seat tube connecting the rear end portions of these tubes, and a rear portion from the vicinity of the connecting portion between the top tube and the seat tube. In the shape of a bicycle frame that extends to the bottom and includes a seat stay connected to the rear end of the chain stay extending rearward from the vicinity of the connection portion between the down tube and the seat tube, the cross-sectional shape of the seat stay and the chain stay is It is vertically long and has a linear tone in the extending direction, and the average value of the aspect ratio of the seat stay is greater than the average value of the aspect ratio of the chain stay, and the aspect ratio of the seat stay is larger on the seat tube side. And connecting the seat tube and the seat stay by continuous surface joining. Wherein the connection has been. Further, the present invention is characterized in that the cross-sectional shape of the top tube is configured as a vertically long inverted triangle. Further, the present invention is characterized in that a rear end portion of the down tube is wound around a bottom bracket shell disposed at a connection portion with the down tube, the seat tube, and the chain stay. Is a means for solving the problem.

According to the present invention, the top tube that extends rearward from the head pipe, the down tube that extends to the lower rear portion, the seat tube that connects between the rear ends of the tubes, and the top, which are constituent elements according to claim 1 In a bicycle frame shape comprising a seat stay extending from the vicinity of the connection portion between the tube and the seat tube to the lower rear portion and connected to the rear end portion of the chain stay extending rearward from the vicinity of the connection portion between the down tube and the seat tube. The seat stay and the chain stay have a vertically long cross-sectional shape and a linear tone in the extending direction, and an average value of the aspect ratio of the seat stay is greater than or equal to an average value of the aspect ratio of the chain stay , and the seat While increasing the aspect ratio of the stay on the seat tube side, the seat tube and the seat stay By connection part is connected by interview if successive, seat stay at higher average value of the aspect ratio seat stay side than the chain stay side, without reducing the rigidity, seat stay side in somewhat upright It is possible to suppress the resistance of air crossing the front and rear direction. Further, since a high moment of inertia of the cross section can be obtained, the weight can be reduced. In addition, compared to the conventional connection between the seat tube and seat stay connected discontinuously, which tends to cause a sudden change in strength, it is possible to achieve a smooth connection without reducing the rigidity of the connecting intersection. In addition, a high rectification function is also exhibited, which is advantageous when traveling at high speed. In addition, even in a seat stay having a large aspect ratio, the connecting portion between the seat tube and the seat stay is connected by continuous surface bonding.

Further, the configuration requirements of claim 2, when configured to the cross-sectional shape of the front Quito Ppuchubu the inverted triangle vertically long, while securing a certain degree of lateral stiffness, to reduce the width, at the time of pedaling Interference with the competitor's knee is reduced, and drastic pedaling is possible even during acceleration.

Furthermore, the configuration requirements of claim 3, the bottom bracket shell disposed in the connection portion between the down tube and the seat tube and chain stays, the rear end of the down tube is configured to engulf In this case, the bottom bracket shell is wound around the rear end of the down tube and can be integrally molded, and since the strength change is small and the rigidity is not lowered, a smooth connection portion without shape change is configured. The rectifying function is also high, which is advantageous when driving at high speeds.

It is a side view which shows the 1st Example of the bicycle frame shape of this invention. FIG. 2 is a perspective view from above and below. It is a figure which shows the aspect ratio of the main each part cross section of a seat stay. It is a figure which shows the aspect ratio of the principal each part cross section of a chain stay. It is each main sectional drawing in a top tube, a down tube, and a seat tube. 2 is a comparison table of secondary moments in the vertical and horizontal cross sections of the frame of the present invention and the conventional mass-produced frame. It is explanatory drawing of the frame shape of the bicycle described in patent document 1 of the prior art example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for implementing a bicycle frame shape of the invention will be described with reference to the drawings. As shown in FIG. 1, the bicycle frame shape of the present invention includes a top tube 2 extending rearward from the head pipe 1, a down tube 3 extending rearwardly, a seat tube 4 connecting between the rear ends of the tubes, A seat stay 5 that extends from the vicinity of the connection portion between the top tube 2 and the seat tube 4 to the lower rear portion and is connected to the rear end portion of the chain stay 6 that extends rearward from the vicinity of the connection portion between the down tube 3 and the seat tube 4. The cross-sectional shape of the seat stay 5 and the chain stay 6 is vertically long and has a linear tone in the extending direction, and the average aspect ratio of the seat stay 5 is the aspect ratio of the chain stay 6. with the constructed above average, to increase further the aspect ratio of the seat stay 5 at the seat tube 4 side, the sheet Wherein the connecting portion between Tochubu 4 and the seat stay 5 is connected by interview if successive.

  FIG. 1 is a side view showing a first embodiment of the bicycle frame shape of the present invention. The frame of the present invention is configured as follows. A top tube 2 extending rearward in a horizontal direction from a head pipe 1 on which a front fork stem formed at the lower part of a front fork that pivotally supports a front wheel at the lower end is omitted, and a down tube 3 extending to the rear lower part. And the diamond frame is comprised from the seat tube 4 which connects between the rear-end parts of these tubes 2 and 3. FIG. A seat post (not shown) with a saddle attached to the upper end is inserted from the top of the seat tube 4. A bottom bracket shell 7 on which a pedal crank (not shown) is pivotally supported is disposed at a connection portion between the lower end portion of the down tube 3 and the lower end portion of the seat tube 4. The bottom bracket shell 7 is made of a light metal such as aluminum.

  In particular, the bicycle frame shape of the present invention extends from the connecting portion between the rear end portion of the top tube 2 and the upper end portion of the seat tube 4 to the rear lower portion and from the connecting portion between the down tube 3 and the seat tube 4 to the rear. A seat stay 5 connected to the rear end portion of the chain stay 6 extending in the direction of the cross-section of the seat stay 5 and the chain stay 6 is vertically long and has a straight line in the extending direction, The average aspect ratio of the seat stay 5 is configured to be greater than or equal to the average aspect ratio of the chain stay 6. Details will be described later in FIG. In FIG. 1, the aspect ratio of the arbitrary cross section AA of the seat stay 5 and the aspect ratio of the arbitrary cross section DD of the chain stay 6 are illustrated. In addition, the range in which the average of the aspect ratio in the seat stay 5 is measured is the range of L5 from the position where the seat stay 5 and the seat tube 4 intersect to the boundary between the rear nail plate 8 and the chain stay 6 The range in which the average of the aspect ratio is measured is the range of L6 from the position where the chain stay 6 and the seat tube 4 intersect to the boundary between the rear nail plate 8 and the rear.

As shown in the perspective views of FIGS. 2A and 2B, the top tube 2, the down tube 3 and the seat tube 4 constituting the diamond frame, the bifurcated fork-like seat stays 5 and 5, and the chain stays 6 and 6 are provided. Is preferably integrally formed in a hollow from a carbon resin or the like. Each member of the rear claw plates 8 and 8 which are attached to the head pipe 1, the seat post clamp, the bottom bracket shell 7 and the connecting portion of the seat stay 5 and the chain stay 6 and support the rear wheel shaft is made of light metal such as aluminum. And bonded to a frame of carbon resin or the like. The connecting portion between the seat tube 4 and the seat stay 5 is connected by continuous surface joining, and is connected to the connecting portion between the seat tube and the seat stay such as a conventional one that is connected in a discontinuous manner that tends to cause a sudden change in strength. In comparison, there is no decrease in rigidity at the connection intersection, and a smooth strength connection is possible, and a high rectification function is also exhibited, which is advantageous during high-speed traveling.

  Further, the bottom bracket shell 7 disposed at the connection portion with the down tube 3, the seat tube 4 and the chain stay 6 is integrally formed so that the rear end portion of the down tube 3 is wound. In this way, the bottom bracket shell 7 is integrally formed in such a manner that the bottom bracket shell 7 is wound around the rear end portion of the down tube 4, so that the connection portion of the down tube 3, the seat tube 4, and the chain stay 6 is firmly secured to the bottom bracket shell 7. In addition, the pedal crank can be supported with high strength, and the change in strength is lessened and the rigidity is not lowered.Therefore, a smooth connection part without shape change is configured and the rectification function is high, which is advantageous at high speeds. Become.

  FIG. 3 is a diagram showing the vertical and horizontal proportions of the cross sections of the main parts of the seat stay. Each of the cross sections AA, BB, and CC is a cross section orthogonal to the extending direction of the seat stay 5. The top tube 2, down tube 3, seat tube 4 and chain stay 6 are also preferably hollow. An AA cross section, a BB cross section, and a CC cross section, which are arbitrary cross sections of the upper, middle, and lower portions of the bifurcated and hollow seat stay 5, are shown. In the upper AA cross section, the inner side has a slightly straight elliptical shape so as to avoid interference with the rear wheels. As exemplified by the AA cross section, the aspect ratio in this cross section is determined by H / W (H is the vertical dimension, W is the horizontal dimension). In the example shown in the figure, there is no description of the dimension example. For example, in the upper AA cross section, H is 45 mm, W is 16 mm, the aspect ratio H / W is 2.8: 1, and the lower CC cross section. In the section, H is 35 mm, W is 14 mm, and the aspect ratio H / W is 2.5: 1. The average aspect ratio of the seat stay is 2.65: 1.

  FIG. 4 is a diagram showing the vertical and horizontal proportions of the cross-section of the main parts of the chain stay. Each of the cross sections DD, EE, and FF is a cross section orthogonal to the extending direction of the chain stay 6. The DD cross section, the EE cross section, and the FF cross section, which are arbitrary cross sections of the front, middle, and rear portions of the bifurcated fork chain stay 6, are illustrated. Presents a rectangular cross section with a slightly swollen side. For example, in the front DD section, H is 48 mm and W is 17 mm, the aspect ratio H / W is 2.8: 1, and in the rear FF section, H is 32 mm and W is 16 mm. The ratio H / W is 2.0: 1. The average aspect ratio of the chain stay is 2.4: 1.

  In the present invention, it is possible to effectively withstand the high reaction force acting on the seat stay 5 side as well as the drag force from the road surface with respect to the high torque generated by the pedal depression force by the top athlete. Further, the average value of the aspect ratio H / W (in each cross section) of the seat stay 5 is configured to be equal to or greater than the average value of the aspect ratio H / W (in each cross section) of the chain stay 6. As a result, the average value of the aspect ratio is higher on the seat stay side than on the chain stay side, and the resistance of air crossing the seat stay in the front-rear direction on the seat stand side in a slightly standing state is suppressed without reducing rigidity. be able to. Further, since a high moment of inertia of the cross section can be obtained, the weight can be reduced.

  FIG. 6 is a comparison table of examples of secondary moments in vertical and horizontal cross sections in the frame of the present invention and a conventional mass-produced frame (referred to as a conventional product). S / S represents the seat stay 5, and C / S represents the chain stay 6. The numerical value in the conventional mass production frame is compared with the numerical value in the frame of the present invention. The upper and lower portions of the seat stay 5 (S / S) are the AA cross section of the upper portion, the numerical values of the lower CC cross section, and the front and rear of the chain stay 6 (C / S) are the DD cross section of the front portion. These are the numerical values in the FF cross section at the rear. The numerical values were compared for the aspect ratio of the hollow frame with the same thickness.

  As a numerical example of the table, in the AA cross section at the top of the seat stay 5 (S / S), the vertical moment of inertia Icu = 14499.0 in the example of the conventional competition bicycle frame, the moment of transverse cross section Icv = 3572.3, the longitudinal moment of inertia of the frame Icu = 485855.7, the moment of inertia of the transverse section Icv = 4795.7, and the ratio of the moment of inertia of the longitudinal section Icu to the conventional product is 3. .35 (335%), and the ratio of the moment of inertia Icv of the present invention to the conventional product is 2.1 (210%). As numerical examples corresponding to the AA cross section in FIG. 3 of the conventional product, W = 14 mm, H = 30 mm, aspect ratio = 2.1: 1, and in the CC cross section, W = 14 mm, H = 20 mm, vertical and horizontal The ratio = 1.4: 1 and the average aspect ratio of the seat stay is 1.75: 1.

  In the lower C-C cross section, the longitudinal section secondary moment Icu = 4441.6 of the conventional product, the transverse section secondary moment Icv = 2322.2, the longitudinal section secondary moment Icu = 221113.9 of the frame of the present invention, The ratio of the secondary moment of inertia Icv = 4057.1 and the moment of inertia of the longitudinal section Icu to the conventional product of 4.98 (498%), the ratio of the moment of inertia of the cross section Icv to the conventional product of the present invention. Is 1.75 (175%). An example of the average value (vertical and horizontal average) of the ratio of the secondary moment of inertia Icu to the conventional product of the frame of the present invention and the ratio of the secondary moment of inertia Icv to the conventional product of the frame of the present invention in the upper AA cross section is 272%.

  An example of the average value (vertical and horizontal average) of the ratio of the vertical moment of inertia Icu to the conventional product of the frame of the present invention in the lower CC cross section and the ratio of the transverse moment of inertia Icv to the conventional product of the present invention is It is 336%, and an example of an average value of the upper and lower cross-sectional portions (vertical average: average of vertical and horizontal averages of the AA cross section and the CC cross section) is 304%.

  In the DD cross section at the front part of the chain stay 6 (C / S), the vertical moment of inertia Icu = 817877.8 of the conventional product, the moment of inertia of the transverse cross section Icv = 14215, and the longitudinal section 2 of the frame of the present invention. The second moment Icu = 74130.0, the transverse moment of inertia Icv = 13230.6, the ratio of the moment of inertia of the longitudinal section Icu to the conventional product is 0.91 (91%), and the moment of inertia of the transverse section Icv is 0.91. The ratio of the present invention to the conventional product is 0.87 (87%). As numerical examples corresponding to the DD section of the conventional product, W = 17 mm, H = 48 mm, aspect ratio = 2.8: 1, and in the FF section, W = 16 mm, H = 25 mm, aspect ratio = 1. The average aspect ratio of the chain stay is 2.2: 1.

  In the rear FF cross section, the vertical section secondary moment Icu = 11249.8 of the conventional product, the transverse section secondary moment Icv = 4882.7, the vertical section secondary moment Icu = 22233.3 of the frame of the present invention, The ratio of the secondary moment of inertia Icv = 653.3, the moment of inertia of the vertical section Icu to the conventional product of 1.98 (198%), the ratio of the secondary moment of inertia Icv of the present invention to the conventional product Is 1.34 (134%).

  Example of the average value of the ratio of the secondary moment of inertia Icu to the conventional product of the frame of the present invention in the front DD section and the ratio of the secondary moment of inertia Icv of the present invention to the conventional product (vertical and horizontal average) Is 89%. An example of the average value (vertical and horizontal average) of the ratio of the secondary moment of inertia Icu to the conventional product of the frame of the present invention at the rear FF cross section and the ratio of the secondary moment of inertia Icv of the present invention to the conventional product is It is 166%, and the example of the average value of the front and rear cross-sectional portions (the front and rear average: the average of the vertical and horizontal averages of the DD cross section and the FF cross section) is 127%.

  As described above, in the embodiment, the average value example 304% of the upper and lower portions in the seat stay 5 is configured to be larger than the average value example 127% in the front and rear portions of the chain stay 6. Therefore, if the rigidity is the same as that of the conventional product, it is possible to suppress the resistance of air crossing on the seat stay side in a slightly standing state without reducing the rigidity. Further, since a high moment of inertia of the cross section can be obtained, the air resistance is small, which is advantageous as a competition equipment, and the weight can be reduced.

  FIG. 5 is a main cross-sectional view of the top tube, down tube, and seat tube. As understood from the GG cross-sectional view, in the present invention, the cross-sectional shape of the top tube 2 is configured as a vertically long inverted triangle. This configuration ensures a certain level of lateral stiffness, reduces the lateral width, ensures vertical stiffness and lateral stiffness during pedaling, and reduces interference with the competitor's knees. For example, it is possible to perform drastic pedaling. As can be understood from the HH cross-sectional view, the down tube 3 is configured in an elliptical shape with a sharp rear edge on the rear side, which is advantageous for a competition in which the rectifying function is enhanced and the vehicle runs at high speed. As can be understood from the II cross-sectional view, the seat tube 4 also has a swelled triangular cross section with a slightly acute angle on the front side, and has a high rectifying function.

  The embodiments of the present invention have been described above, but within the scope of the present invention, the ratio of the length of each frame in the frame comprising the head pipe, the top tube, the down tube, the seat tube, the seat stay and the chain stay. Shapes, materials (preferably carbon resin, but may be titanium or aluminum) and cross-sectional shapes (non-objective elliptical shapes, bulging rectangles, etc., as in the examples) are preferred hollow shapes having the same thickness However, the thickness may not be the same), the ratio of the average aspect ratio of the seat stay and the chain stay (the average value should be larger on the seat stay side than the chain stay side), the seat tube and the seat stay Consecutive surface joining form with the connecting part of the seat (Side tube side and seat stay side are almost flush with each other The continuous form is optimal, but it may not be flush as long as it does not affect the rectifying function), the top tube has an inverted triangular cross-sectional shape, the down tube and seat tube, and the connection to the chain stay Winding form of the rear end of the down tube relative to the bottom bracket shell to be installed (The rear end of the down tube may be wound in a form in which the bottom bracket shell is attached to the front end of the chain stay, or the bottom bracket shell is used as the down tube. The head end of the chain stay may be joined to the rear end of the down tube although it is wound around the rear end, and the head pipe of the different material (light metal, etc.) for each frame (shaft support of the front fork) Cylinder), seat post insertion cylinder mounted in the seat tube, bottom bra It can be adopted as appropriate for Ttosheru and rear nail plate like attached form or the like. In addition, the specifications described in the examples are merely examples in all respects and should not be interpreted in a limited manner.

  The bicycle frame shape of the present invention is preferably applied to a competition bicycle used by a top athlete participating in the Olympics or the like, but can also be adopted for a bicycle for an amateur athlete.

1 Head pipe 2 Top tube (T / T)
3 Down tube (D / T)
4 Seat tube (S / T)
5 Seat stay (S / S)
6 Chain stay (C / S)
7 Bottom bracket shell (B / B)
8 Rear nail plate

Claims (3)

A top tube extending rearward from the head pipe, a down tube extending rearwardly, a seat tube connecting between the rear ends of the tubes, and extending from the vicinity of the connecting portion between the top tube and the seat tube to the rear lower portion, In a bicycle frame shape comprising a seat stay connected to the rear end portion of the chain stay extending rearward from the vicinity of the connection portion between the down tube and the seat tube, the cross-sectional shape of the seat stay and the chain stay is a vertically long shape, and A linear tone in the extending direction, the average value of the aspect ratio of the seat stay is configured to be equal to or greater than the average value of the aspect ratio of the chain stay, and the aspect ratio of the seat stay is increased on the seat tube side, and the seat tube Patent that the connection portion of the seat stay is connected by interview if contiguous with Bicycle frame shape to be. The bicycle frame shape according to claim 1, wherein the cross-sectional shape of the top tube is a vertically long inverted triangle. The bicycle according to claim 1 or 2 , wherein a rear end portion of the down tube is wound around a bottom bracket shell disposed at a connection portion with the down tube, the seat tube, and the chain stay. Frame shape.

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