Title of Invention

"STEP MOUNTING STRUCTURE IN MOTORCYCLE"

Abstract

[Solving Means] A bracket 22 is mounted to a lower portion of an engine 7 of a motorcycle, and a step bar 27 is mounted through dampers 23 to the bracket 22. Steps 28 are provided on the step bar 27. Further, a side stand bracket 31 is fixed to the bracket 22, and a side stand 32 is swingably mounted to the side stand bracket 31. [Effect] The steps are mounted through other members to the engine, so that it is not necessary to change the design of an existing body frame for the purpose of mounting of the steps. Heat of the engine is dissipated from the bracket, and its temperature rapidly falls, so that the dampers are not affected by the heat. The dampers absorb vibrations of the engine to thereby weaken vibrations to be transmitted to the steps to an insensitive degree. Since the side stand bracket is fixed to the bracket, a force due to the vehicle body weight in a parking condition is not transmitted to the dampers, thereby suppressing deterioration of the dampers.

Full Text

[DETAILED DESCRIPTION OF THE INVENTION] [Technical Field to Which the Invention Pertains] The present invention relates to a step mounting structure in a motorcycle. [Prior Art] In general, a motorcycle has a rider's step assembly for supporting the rider's feet and a passenger's step assembly for supporting the passenger's feet. The rider's step assembly is a part having a possible influence upon the operation of a gearshift pedal and the operation of a brake pedal, so that the rider's step assembly is fixed to an engine or a body frame of the motorcycle at a suitable position where the assembly does not interfere with the operability of these pedals. A fixing structure of the rider's step assembly to the body frame is described in Japanese Utility Model Laid-open No. 64-32292 entitled "Step Structure in Vehicle", for example. As shown in FIGS. 1 and 2 of this publication, a step bracket 10 is mounted through an elastic member 13 and a rubber mount 15 between a pair of right and left frame lower members 2A and 2B of a four-wheeled vehicle, and two steps 18 are mounted to the step bracket 10. With this structure, vibrations of an engine 7 are attenuated by the elastic member 13 to thereby suppress or reduce transmission of the vibrations to a rider . [Problem to be Solved by the Invention] In the case of applying the above technique to a motorcycle not having the frame lower members 2A and 2B, the step bracket 10 and the steps 18 are mounted through the elastic member 13 to the engine 7 having rigidity. Accordingly, vibrations of the engine 7 can be suppressed by the elastic member 13, but deterioration of the elastic member 13 is accelerated by heat of the engine 7. In the case of changing the design of an existing body frame to add the frame lower members to a motorcycle, a design/production cost of the body frame is affected. It is accordingly an object of the present invention to provide a step mounting structure in a motorcycle which can suppress vibrations with no influence of heat and does not affect the design of a body frame. [Means for Solving the Problem] The invention as defined in claim 1 is characterized in that a bracket is mounted to a lower portion of an engine of said motorcycle, in that a step bar is mounted through a damper to said bracket, and in that a step is provided on said step bar. The bracket is mounted to the lower portion of the engine, and the damper is mounted to the bracket. Accordingly, heat of the engine is transmitted to the bracket, and is then dissipated from the outer surface of the bracket to the atmosphere. As a result, the damper is not affected by the heat from the engine. The step bar is mounted through the damper to the bracket, and the step is mounted to the step bar. Accordingly, vibrations of the engine are transmitted through the bracket to the damper, and weakened by the vibration absorbing operation of the damper. As a result, vibrations to be transmitted from the damper to the step bar can be so weakened as not to be sensed by the rider's feet. The invention as defined in claim 2 is characterized in that a side stand bracket is fixed to said bracket, and a side stand is swingably mounted to said side stand bracket. The side stand bracket is fixed to the bracket. Accordingly, in the case of operating the side stand, a force due to the weight of the vehicle body is transmitted from the engine through the bracket and the side stand bracket to the side stand. This force is not applied to the damper, so that the damper is not subjected to a compressive force due to the vehicle body weight. The invention as defined in claim 3 is characterized in that said bracket is provided with a brake pedal stopper. With this structure, a load applied from the rider's foot to the step is transmitted from the step through the step bar to the damper, but not transmitted to the brake pedal stopper. Thus, such a load as a rider's weight is not applied to the brake pedal stopper. Accordingly, the present invention related to a step mounting structure in a motorcycle, in which a step bar (27, 53) is arranged on the lower portion of an engine (7), characterized in that a bracket (22, 51) extends laterally in parallel with a bottom of said engine (7) and is fixed to said engine (7), said bracket (22, 51) having plate portions (22a) which extend laterally outwardly with respect to the fixed portions thereof to said engine (7), a damper mounted to the said bracket (52) is provided for absorbing vibration from said engine (7), said step bar (27, 53) has right and left plate portions (27b, 27c), said right and left plate portions (27b, 27c) being fixed through the intermediary of said damper (52) to lower surfaces of said plate portions (22a) of said bracket (22), and [BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS] [FIG. 1] FIG. 1 is a left side view of a motorcycle according to a first preferred embodiment of the present invention. [FIG. 2] FIG. 2 is a right side view of the motorcycle according to the first preferred embodiment of the present invention. [FIG. 3] FIG. 3 is a cross section taken along the line 3-3 in FIG. 1. [FIG. 4] FIG. 4 is an exploded perspective view of a step mounting structure according to the first preferred embodiment of the present invention. [FIG. 5] FIG. 5 is a cross section taken along the line 5-5 in FIG. 3. [FIG. 6] FIG. 6 is a schematic view for illustrating heat conduction in the step mounting structure according to the first preferred embodiment of the present invention. [FIG. 7] FIG. 7 is a schematic view for illustrating transmission of forces in the step mounting structure according to the first preferred embodiment of the present invention. [FIG. 8] FIG. 8 is a sectional view similar to FIG. 3, showing a second preferred embodiment of the step mounting structure according to the present invention. [FIG. 9] FIG. 9 is a sectional view of an essential part of the step mounting structure shown in FIG. 8. [Mode for Carrying out the Invention] Some preferred embodiments of the present invention will now be described with reference to the attached drawings. Each drawing is to be viewed in the same orientation as that of reference numerals included therein, and the terms of "front", "rear", "right", and "left" used in this specification are regarded as orientations with reference to a rider position. FIG. 1 is a left side view of a motorcycle 1 according to a first preferred embodiment of the present invention. The motorcycle 1 includes a body frame 2, a head pipe 3 fixed to the front end of the body frame 2, a handle 4 and a front fork 5 both steerably mounted to the head pipe 3, a front wheel 6 rotatably mounted to the front fork 5, an engine 7 located at a central lower portion of the body frame 2, a fuel tank 8 and a seat 9 both located at an upper portion of the body frame 2, a swing arm 11 vertically swingably extending rearward from the central lower portion of the body frame 2, a rear wheel 12 rotatably mounted to a rear portion of the swing arm 11, a rear sprocket 13 mounted to the rear wheel 12, a chain 14 for transmitting a drive force to the rear sprocket 13, a main stand 15 mounted to a lower portion of the body frame 2, a passenger's step assembly 16, and a rider's step assembly 20 mounted to a lower portion of the engine 7. Reference numerals 30 and 32 denote a gearshift pedal and a side stand, respectively. FIG. 2 is a right side view of the motorcycle 1 according to the first preferred embodiment of the present invention. Reference numerals 17, 18, and 19 denote a silencer, a kick pedal, and a brake pedal, respectively. FIG. 3 is a cross section taken along the line 3-3 in FIG. 1, showing a condition where the side stand 32 is lowered. The rider's step assembly 20 includes a bracket 22 mounted to a lower portion of the engine 7 by a plurality of (four) bolts 21, a step bar 27 mounted through a plurality of (four) dampers 23 to the bracket 22 by a plurality of (four) bolts 24, nuts 25, and collars 26, a pair of right and left elastic steps 28 provided at the opposite ends of the step bar 27, a side stand bracket 31 fixed to the bracket 22 so as to be inclined at a given angle, and the side stand 32 swingably mounted to the side stand bracket 31. The lower portion of the engine 7 at which the bracket 22 is mounted is formed with four projections 7a (two rear ones of which being shown in FIG. 3) , each being formed with an internal screw thread. The left step 28 is set at a level corresponding to the level of the gearshift pedal 30, and the right step 28 is set at a level corresponding to the level of the brake pedal 19. FIG. 4 is an exploded perspective view of a step mounting structure in the motorcycle 1 according to the first preferred embodiment of the present invention. The bracket 22 includes a first plate portion 22a, a first rod portion 22b welded to the first plate portion 22a, and a brake pedal stopper 22c bent downward from the first plate portion 22a. Each damper 23 is a hollow cylindrical member having an annular groove 23a at the axially central position, for supporting the step bar 27. Each damper 23 is suitably formed of rubber or soft resin. Each collar 26 is formed of metal, and it consists of a hollow cylindrical portion 26a and a flange portion 26b formed at the lower end of the hollow cylindrical portion 26a. The hollow cylindrical portion 26a functions to bear a tightening force of the corresponding bolt 24, thereby preventing excess compression of the corresponding damper 23. The step bar 27 includes a second rod portion 27a, a second plate portion 27b welded to a left portion of the second rod portion 27a, and a third plate portion 27c welded to a right portion of the second rod portion 27a. Each of the second and third plate portions 27b and 27c has a pair of mounting holes 27d. The side stand bracket 31 includes an inclined plate 33 welded to the bracket 22 so as to be inclined at a given angle with respect thereto, a reinforcing plate 34 welded both to the inclined plate 33 and to the first rod portion 22b, and a first hook member 35 welded to the inclined plate 33. The side stand 32 includes a pivot member 36 pivotably mounted to the side stand bracket 31, a support 37 welded at one end thereof to the pivot member 36, a base plate 38 welded to the other end of the support 37, a second hook member 39 fixed to the support 37, an extension spring 41 connecting the first hook member 35 and the second hook member 39, and a bolt 42 and nut 43 for mounting the pivot member 36 to the inclined plate 33. The extension spring 41 serves to raise the side stand 32 to its upper rest position. An example of an assembling process for the rider's step assembly 20 will now be described. In the first step, the bracket 22 is fixed to the lower portion of the engine 7 (see FIG. 3) by the four bolts 21. In the second step, the annular grooves 23a of the four dampers 23 are fitted to the four mounting holes 27d of the step bar 27, respectively. In the third step, the hollow cylindrical portions 26a of the four collars 26 are inserted into the four dampers 23, respectively, and the four bolts 24 are inserted into the four collars 26, respectively. Then, the four bolts 24 are secured to the four nuts 25 with a given tightening torque, respectively. Finally, the pivot member 36 of the side stand 32 is mounted to the side stand bracket 31 by the bolt 42 and the nut 43, and the extension spring 41 is engaged at its opposite ends to the first and second hook members 35 and 39. The assembly thus obtained is shown in FIG. 3. FIG. 5 is a cross section taken along the line 5-5 in FIG. 3. FIG. 5 shows that the four dampers 23 (the left two ones of which being shown) are mounted to the bracket 22 by the bolts 24 and the collars 26 and that the step bar 27 is supported at the axially central position of each damper 23 so that the step bar 27 is not in direct contact with the bracket 22. Each nut 25 is welded to the bracket 22, so that a troublesome work for holding each nut 25 with a tool can be eliminated and possible interference of the tool with the engine 7 can also be avoided. The operation of the step mounting structure in the motorcycle 1 mentioned above will now be described. In the step mounting structure shown in FIG. 5, the bracket 22 is mounted to the engine 7 (see FIG. 3), and the step bar 27 is mounted through the dampers 23 to the bracket 22. Accordingly, vibrations of the engine 7 are transmitted to the bracket 22, next transmitted from the bracket 22 to the dampers 23, and finally absorbed by the vibration absorbing operation of the dampers 23 . As a result, vibrations to be transmitted from the dampers 23 to the step bar 27 become so weak as not to be sensed by the rider's feet. The bracket 22 is provided with the brake pedal stopper 22c against which the brake pedal 19 abuts, thereby positioning the brake pedal 19. Although not shown, an upward tensile force is normally applied to the brake pedal 19 by a return spring. By the provision of the brake pedal stopper 22c on the bracket 22, a load applied from the rider's feet to the steps 28 (see FIG. 3) is transmitted from the steps 28 through the step bar 27 to the dampers 23, but not transmitted to the brake pedal stopper 22c. Thus, such a load as a rider's weight is not applied to the brake pedal stopper 22c, thereby preventing displacement of the brake pedal stopper 22c, so that the brake pedal 19 can be maintained at its initial position. FIG. 6 is a schematic view for illustrating heat conduction in the step mounting structure according to the first preferred embodiment of the present invention. Heat of the engine 7 is transmitted from the engine 7 to the bracket 22 as shown by arrows Al . The heat transmitted to the bracket 22 spreads over the bracket 22 as shown by arrows A2 . Then, the bracket 22 dissipates the heat from its outer surface to the atmosphere as shown by white arrows A3 . Since the bracket 22 is provided with the first plate portion 22a having a large surface area, the temperature of the bracket 22 rapidly falls. Accordingly, heat conduction from the bracket 22 to the dampers 23 as shown by broken- line arrows A4 hardly occurs, so that the dampers 23 are hardly influenced by the heat from the engine 7 . Accordingly, ft is not necessary to use an expensive material having heat resistance for the dampers 23, thereby suppressing a production cost of the rider's step assembly 20 (see FIG. 3) . FIG. 7 is a schematic view for illustrating transmission of forces in the step mounting structure according to the first preferred embodiment of the present invention, showing a condition where the motorcycle 1 is parked with the side stand 32 lowered. Unlike the main stand 15 (see FIG. 1), the side stand 32 is operated to support the vehicle body in such a manner that the vehicle body is inclined to the left side thereof and the base plate 38 of the side stand 32 lowered touches the ground. In such a parking condition, the side stand 32, the front wheel 6, and the rear wheel 12 (see FIG. 1) cooperate to support the weight of the vehicle body. That is, a load Ff is applied to the front wheel 6, and a load is similarly applied to the rear wheel 12. Further, a load Fs is applied to the side stand 32. The center of gravity of the motorcycle 1 parked falls in an area enclosed by three points where the front wheel 6, the rear wheel 12, and the side stand 32 touch the ground, thereby ensuring a stable parking condition. With the mounting structure of the side stand 32 wherein the side stand bracket 31 is mounted on the bracket 22, a force is transmitted from the engine 7 through the first plate portion 22a and the first rod portion 22b of the bracket 22 to the side stand bracket 31 as shown by arrows A5 . The force transmitted to the side stand bracket 31 is further transmitted to the side stand 32. Accordingly, the force from the engine 7 is not transmitted to the dampers 23, so that a compressive force due to the vehicle body weight is not applied to the dampers 23. As a result, the side stand 32 has no influence upon the dampers 23, thereby suppressing deterioration of the dampers 23. Furthermore, since the force is not transmitted to the dampers 23 in the parking condition, there is no possibility of oscillation in the side stand 32 due to the vibration absorbing function of the dampers 23, thus improving the stability of the parking condition by the three-point configuration. FIG. 8 is a sectional view similar to FIG. 3, showing a second preferred embodiment of the step mounting structure according to the present invention. In the following description, substantially the same parts as those of the first preferred embodiment shown in FIGS. 3 and 4 will be denoted by the same reference numerals and the description thereof will be omitted. Reference numeral 50 generally denotes a rider's step assembly in the second preferred embodiment. The rider's step assembly 50 includes a bracket 51 mounted to a lower portion of an engine 7 by a plurality of bolts 21, a side stand bracket 31 welded to the bracket 51, a pair of right and left step bars 53 (the left one being not shown) each mounted through a damper 52 to the bracket 51, a pair of right and left elastic steps 28 provided on the pair of step bars 53, respectively, first and second seat plates 54 and 55 holding the opposite axial ends of the damper 52 mounted to each step bar 53, and a pair of right and left bolts 56 each for fixing the damper 52 through the first and second seat plates 54 and 55 to the corresponding step bar 53 . Reference numerals 57 denote bolts, and reference numerals 58 denote nuts welded to the right and left first seat plates 54 for securing the bolts 57. A side stand having the same structure as that of the side stand 32 shown in FIG. 3 is mounted to the side stand bracket 31, but not shown in FIG. 8. The bracket 51 includes a rod portion 51a, a first plate portion 51b welded to a left portion of the rod portion 51a, a right plate portion 51c welded to a right portion of the rod portion 51a, and a pair of right and left support plates 51d welded to the opposite ends of the rod portion 51a. The outer surface of the bracket 51 operates to dissipate heat of the engine 7, and the support rods 51d are located apart from the engine 7, so that the dampers 52 are not influenced by the heat from the engine 7 . The operation of the side stand in the second preferred embodiment will now be described. The side stand bracket 31 is mounted on the bracket 51. Accordingly, a force due to the vehicle body weight in the parking condition is transmitted from the engine 7 through the bracket 51 and the side stand bracket 31 to the side stand. Thus, the force is not transmitted to the dampers 52, so that the dampers 52 are not influenced by the side stand. FIG. 9 is a sectional view of an essential part of the step mounting structure in the second preferred embodiment of the present invention, showing the right step bar 53 mounted through the upper damper 52 to the bracket 51. Reference numeral 59 denotes a collar inserted in a lower damper 52 . While the mounting structure of the right step bar 53 is shown in FIG. 9, the left step bar (not shown) is also mounted by the same structure . The support plate 51d is formed of metal, and it is formed at its upper portion with a pair of upper and lower holes 51e. Each damper 52 is a hollow cylindrical member having an annular groove 52a at the axially central position, for supporting the corresponding step bar 53. Each damper 52 is suitably formed of rubber or soft resin The step bar 53 includes a body 53a, a rubber fixing plate 53b welded to the body 53a, and an internal screw thread 53c formed in an end portion of the body 53a. The step bar 53 is mounted in the following manner. In the first step, the annular grooves 52a of the upper and lower dampers 52 are fitted into the upper and lower holes 51e of the support plate 51d, and the collar 59 is inserted into the lower damper 52. In the next step, the first and second seat plates 54 and 55 are put on the opposite ends of the upper and lower dampers 52, and the bolt 57 is inserted through the collar 59 and screwed into the nut 58. Finally, the step bar 53 integrated with the step 28 is inserted through the second seat plate 55 and into the upper damper 52, and the bolt 56 is screwed into the internal screw thread 53c of the step bar 53 . The operation of the step mounting structure in the second preferred embodiment will now be described. Each step bar 53 is mounted through the dampers 52 to the bracket 51. Accordingly, vibrations of the engine 7 (see FIG. 8) are transmitted through the bracket 51 to the dampers 52, and are finally weakened by the vibration absorbing operation of the dampers 52. As a result, vibrations to be transmitted from the dampers 52 to each step bar 53 become so weak as not to be sensed by the rider's feet. In modification, the side stand bracket 31 and the side stand 32 may be removed from the rider's step assembly 20 shown in FIG. 3, and only the main stand 15 shown in FIG. 1 may be used for parking. [Effect of the Invention] The present invention can exhibit the following effects by the above configurations. According to claim 1, the bracket is mounted to the lower portion of the engine of a motorcycle, and the damper is mounted to the bracket. Accordingly, heat of the engine is transmitted to the bracket, and is dissipated from the outer surface of the bracket to the atmosphere. As a result, the damper is not affected by the heat from the engine, thereby suppressing deterioration of the damper. Further, the step bar is mounted through the damper to the bracket, and the step is mounted to the step bar. Accordingly, vibrations of the engine are transmitted through the bracket to the damper, and weakened by the vibration absorbing operation of the damper. As a result, vibrations to be transmitted from the damper to the step bar can be so weakened as not to be sensed by the rider's feet. Accordingly, the rider's step assembly capable of suppressing vibrations can be located at a given position where a pedal operation is allowed from the lower portion of the engine in an existing motorcycle having no frame lower members. Therefore, it is not necessary to change the design of an existing body frame, thereby reducing a production cost of the body frame. According to claim 2, the side stand bracket is fixed to the bracket, and the side stand is mounted to the side stand bracket. Accordingly, in the case of operating the side stand, a force due to the weight of the vehicle body is transmitted from the engine through the bracket and the side stand bracket to the side stand. This force is not applied to the damper, so that the damper is not subjected to an compressive force due to the vehicle body weight. As a result, the damper is not affected by the vehicle body weight, thereby suppressing deterioration of the damper. Further, since the force is not applied to the damper in the parking condition, there is no possibility of oscillation in the side stand due to the vibration absorbing function of the damper, thereby improving the stability of the parking condition by the three-point configuration comprising the front wheel, the rear wheel, and the side stand. According to claim 3, the bracket is provided with the brake pedal stopper. Accordingly, a load applied from the rider's foot to the step is transmitted from the step through the step bar to the damper, but not transmitted to the brake pedal stopper. Thus, such a load as a rider's weight is not applied to the brake pedal stopper. As a result, downward displacement of the brake pedal by the brake pedal stopper can be prevented to thereby normally maintain the initial position of the brake pedal . [Explanation of Reference Numerals] 1 ... motorcycle; 2 ... body frame; 7 ... engine; 20, 50 ... rider's pedal assembly; 22, 51 ... bracket; 22c ... brake pedal stopper; 23, 52 ... damper; 27, 53 ... step bar; 28 ... step; 31 ... side stand bracket; 32 ... side stand; 36 ... pivot member. FIG. 3 A: LEFT B: RIGHT FIG. 4 A: FRONT B: REAR C: RIGHT D: LEFT FIG. 8 A: LEFT B: RIGHT We Claim: 1. A step mounting structure in a motorcycle, in which a step bar (27, 53) is arranged on the lower portion of an engine (7), characterized in that a bracket (22, 51) extends laterally in parallel with a bottom of said engine (7) and is fixed to said engine (7), said bracket (22, 51) having plate portions (22a) which extend laterally outwardly with respect to the fixed portions thereof to said engine (7), a damper mounted to the said bracket (52) is provided for absorbing vibration from said engine (7). said step bar (27, 53) has right and left plate portions (27b, 27c), said right and left plate portions (27b, 27c) being fixed through the intermediary of said damper (52) to lower surfaces of said plate portions (22a) of said bracket (22), and 2. A step mounting structure in a motorcycle as claimed in claim 1, wherein said damper (52) has two pair of dampers, each pair of which is arranged in right and left sides of said step bar (27, 53). 3. A step mounting structure in a motorcycle as claimed in claim 1, wherein said bracket (22) has a side stand bracket (31) fixed thereto 5. A step mounting structure in a motorcycle substantially as herein before described with reference to and as illustrated in the foregoing description and the accompanying drawings.

Documents:

879-del-1999-abstract.pdf

879-del-1999-claims.pdf

879-del-1999-correspondence-others.pdf

879-del-1999-correspondence-po.pdf

879-del-1999-description (complete).pdf

879-del-1999-drawings.pdf

879-del-1999-Form-1.pdf

879-del-1999-form-19.pdf

879-del-1999-form-2.pdf

879-del-1999-form-3.pdf

879-del-1999-form-5.pdf

879-del-1999-gpa.pdf

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