WO2016159891A1

WO2016159891A1 - Seat spring structure for motorcycle

Info

Publication number: WO2016159891A1
Application number: PCT/TH2015/000019
Authority: WO
Inventors: Yasuyuki Maeda; Kotaro Fujiyama; Tomoyoshi TATEOKA; Kazuki Yamagishi
Original assignee: Honda Motor Co., Ltd.
Priority date: 2015-03-31
Filing date: 2015-03-31
Publication date: 2016-10-06
Also published as: JP6405057B2; JP2018507813A

Abstract

Provided is a seat spring structure for a motorcycle, the structure including both an open-seat retainer spring and a closing-seat damper spring. The structure can be easily assembled and disassembled and have few spatial limitations. A seat spring structure for a motorcycle includes: a seat hinge structure openably retaining a seat 1, on which a driver can sit, to a vehicle body with at least a hinge shaft; an open-seat retainer structure included in the seat hinge structure and including a seat opening spring 5 capable of retaining the seat 1 at a seat open position in an open state and applying biasing force to a cam structure 6 and a cam 7; and a closing-seat damper spring 8 included in the seat hinge structure and applying biasing force in a seat opening direction. The open-seat retainer structure is provided to one side of the hinge shaft in an axial direction thereof. The closing-seat damper spring 8 is provided, separately from the hinge shaft, to another side of the hinge shaft in the axial direction thereof and is fitted to a spring stay 9 that is attachable to and detachable from the seat hinge structure.

Description

SEAT SPRING STRUCTURE FOR MOTORCYCLE

Technical Field

The present invention relates to a seat spring structure for a motorcycle in which a seat on which a driver can sit is freely openable with a hinge shaft.

Background

As an example of a conventional motorcycle in which a seat is openable with a seat hinge provided to sides of the seat, a structure has been developed that includes a seat spring structure composed of a vehicle-body-side hinge (76) mounted on a vehicle body and a seat- side hinge (51) swingably mounted on the vehicle-body-side hinge (76) as disclosed in Patent Literature 1 , for example. The seat-side hinge (51) in the conventional seat spring structure includes a stopper structure (85, 86, 87) to retain the seat at the open position, a coil spring (107) that applies biasing force to a stopper when the seat is open, and a helical spring (1 1 1) that applies biasing force in the opening direction when the seat is being opened. The helical spring (111) applies biasing force to the seat in the opening direction and thus functions as a damper in the closing direction when the seat is being closed, thereby preventing the seat from closing abruptly.

Citation List

Patent Literature

Patent Literature 1 : Japanese Patent No. 465901 1

Summary

Technical Problem

The seat spring structure in the conventional motorcycle, however, has the following problems. Since the helical spring (1 1 1) is mounted coaxially with a hinge shaft (77) in the seat spring structure, the helical spring (111) needs to be set at the same time during the process of mounting the seat with a seat hinge inserted, which impairs assembly workability. Furthermore, the seat needs to be removed during replacement of the helical spring (11 1). In addition, since the coil spring (107) needs to be set to the center of the hinge shaft, the helical spring needs to be split in half, resulting in spatial limitations. The present invention has been made in view of the foregoing and aims to provide a seat spring structure for a motorcycle, the structure including both an open-seat retainer spring and a closing-seat damper spring. The structure can be easily assembled and disassembled and have few spatial limitations.

Solution to Problem

An invention according to claim 1 provides a seat spring structure for a motorcycle that includes: a seat hinge structure openably retaining a seat, on which a driver can sit, to a vehicle body with at least one hinge shaft; an open-seat retainer structure included in the seat hinge structure and including a seat opening spring capable of retaining the seat at a seat open position in an open state and applying biasing force to a cam structure and a cam; and a closing-seat damper spring included in the seat hinge structure and applying biasing force in a seat opening direction. The open-seat retainer structure is provided to one side of the hinge shaft in an axial direction thereof. The closing-seat damper spring is provided, separately from the hinge shaft, to another side of the hinge shaft in the axial direction thereof and is fitted to a spring stay that is attachable to and detachable from the seat hinge structure.

An invention according to claim 2 provides the seat spring structure for a motorcycle according to claim 1 , in which the seat hinge structure includes a vehicle-body-side hinge and a seat-side hinge. The spring stay includes a pipe frame part that retains the closing-seat damper spring and a stopper cam part abuttable on a notch defined in the vehicle-body-side hinge, and the stopper cam part is bolted in a state in which the stopper cam part is abutted and positioned on the notch. One end of the closing-seat damper spring is hooked to a pin provided to the seat-side hinge, and another end of the closing-seat damper spring is hooked to the vehicle-body-side hinge.

An invention according to claim 3 provides the seat spring structure for a motorcycle according to claim 1 , in which the seat hinge structure retains the seat openable toward a side, and is mounted outside one seat frame part provided under the seat. An electrical component is mounted on an inner side of the seat frame part. The closing-seat damper spring and the electrical component are covered with a common cover.

An invention according to claim 4 provides the seat spring structure for a motorcycle according to claim 2, in which the seat hinge structure includes the seat-side hinge and the vehicle-body-side hinge for retaining the seat openable toward a side, and the seat-side hinge includes two amis in front and rear directions of the vehicle body. The vehicle-body-side hinge includes a U-shaped stay that supports the two arms on a front wall part and a rear wall part with the hinge shafts. The seat opening spring is disposed near the front arm, and the closing-seat damper spring is disposed near the rear arm. A mounting bolt for the spring stay mounts the spring stay to the vehicle-body-side hinge at a substantially center part of a U- shaped stay.

An invention according to claim 5 provides the seat spring structure for a motorcycle according to claim 4, in which the two arms of the seat-side hinge each have a protrusion, the vehicle-body-side hinge includes a pin member with which the protrusion comes into contact when the seat is opened at a certain angle, and the other end of the closing-seat damper spring is hooked to the pin member.

An invention according to claim 6 provides the seat spring structure for a motorcycle according to claim 2, in which the pipe frame part is provided coaxially with the hinge shaft for the seat, and supports the closing-seat damper spring in a cantilever manner at a front side of the vehicle body.

An invention according to claim 7 provides the seat spring structure for a motorcycle according to claim 1 , in which the seat includes a seat support frame that retains the seat, and the seat support frame is coupled with the seat hinge structure. A part of the seat support frame is configured to be exposed outside. The seat spring structure has an under-seat open space with open sides under the seat.

Advantageous Effects of Invention

In the invention according to claim 1 , the open-seat retainer structure is provided to one side of the hinge shaft in the axial direction thereof, and the closing-seat damper spring is provided, separately from the hinge shaft, to the other side of the hinge shaft in the axial direction thereof and is fitted to the spring stay that is attachable to and detachable from the seat hinge structure, and thus the structure can be easily assembled and disassembled.

Furthermore, because the closing-seat damper spring is disposed in the space of the hinge shaft on the side opposite to the stopper structure including the seat opening spring, a seat spring structure that has few spatial limitations in the layouts of the both can be provided. In addition, the closing-seat damper spring can be easily employed, which facilitates general application of this structure to various types of motorcycles. The structure thus provided has commercial advantages of requiring reduced power for opening and closing the seat and absorbing the opening and closing speed of the seat. In the invention according to claim 2, the seat hinge structure includes a vehicle-body- side hinge and a seat-side hinge. The spring stay includes a pipe frame part that retains the closing-seat damper spring and a stopper cam part abuttable on a notch defined in the vehicle- body-side hinge, and is bolted while being positioned with the stopper cam part abutted on the notch. One end of the closing-seat damper spring is hooked to a pin provided to the seat-side hinge, and another end of the closing-seat damper spring is hooked to the vehicle-body-side hinge. In this structure, the stopper cam part in the spring stay is hooked to the notch in the vehicle-body-side hinge, providing a rotation-stopper function, and thus the closing-seat damper spring can be easily positioned accurately, and the structure can be easily assembled and disassembled for maintenance.

In the invention according to claim 3, the seat hinge structure retains the seat openable toward a side, and is mounted outside one seat frame part provided under the seat. The electrical component is mounted on the inner side of the seat frame part. The closing-seat damper spring and the electrical component are covered with the common cover. This structure provides good appearance and can reduce the number of parts required.

In the invention according to claim 4, the seat hinge structure includes the seat-side hinge and the vehicle-body-side hinge for retaining the seat openable toward a side, and the seat-side hinge includes the two arms in the front and rear directions of the vehicle body. The vehicle-body-side hinge includes a U-shaped stay that supports the two arms on a front wall part and a rear wall part with the hinge shafts. The seat opening spring is disposed near the front arm, and the closing-seat damper spring is disposed near the rear arm. The mounting bolt for the spring stay mounts the spring stay to the vehicle-body-side hinge at the

substantially center part of the U-shaped stay. In this structure, the seat opening spring and the closing-seat damper spring will not hamper the fastening or removal of the mounting bolt.

In the invention according to claim 5, the two arms of the seat-side hinge each have a protrusion, the vehicle-body-side hinge includes the pin member with which the protrusion comes into contact when the seat is opened at a certain angle, and the other end of the closing- seat damper spring is hooked to the pin member. In this structure, the closing-seat damper spring is disposed near the pin member, and thus the hooking part of the other end of the closing-seat damper spring can be made short. In addition, the pin member can serve as both a stopper for the seat at the open position and a hook for the other end of the closing-seat damper spring, which eliminates the need for any special member for these purposes. In the invention according to claim 6, the pipe frame part is provided coaxially with the hinge shaft for the seat, and supports the closing-seat damper spring in a cantilever manner at the front side of the vehicle body. With this structure, the closing-seat damper spring can be desirably operated, and the closing-seat damper spring can be easily fitted and removed for maintenance.

In the invention according to claim 7, the seat includes the seat support frame that retains the seat, and the seat support frame is coupled with the seat hinge structure. A part of the seat support frame is configured to be exposed outside. The seat is mounted on a motorcycle that has the under-seat open space with open sides under the seat. In such a motorcycle that has the under-seat open space and exposes a part of the seat support frame outside, thereby having an intensive impression of the naked feel, even when the weight of the seat increases with larger-diameter seat support frames to further enhance the naked feel, the seat can be popped up when opened by the action of the closing-seat damper spring, which reduces power required for operating the seat in the opening direction. Furthermore, when the seat, which has been retained and tightened by the seat opening spring, is being closed, the speed of the seat in the closing direction can be absorbed by the closing-seat damper spring, which facilitates the opening and closing of the seat in the motorcycle with larger-diameter seat support frames. Brief Description of Drawings

[Fig. 1] Fig. 1 is a side view illustrating a motorcycle to which a seat spring structure according to an embodiment of the present invention is applied.

[Fig. 2] Fig. 2 is a perspective view illustrating an opened state of the seat of the motorcycle, to which the seat spring structure for a motorcycle is applied.

[Fig. 3] Fig. 3 is a perspective view illustrating a state where the seat, to which the seat spring structure for a motorcycle is applied, and a vehicle-body-side hinge of the motorcycle are removed from the vehicle body.

[Fig. 4] Fig. 4 is an exploded perspective view illustrating the seat spring structure of the motorcycle.

[Fig. 5] Fig. 5 is a sectional view illustrating the seat spring structure (the seat in the closed state) of the motorcycle and an electrical component in an assembled state.

[Fig. 6] Fig. 6 is a sectional view and a plan view of the seat spring structure

(the seat in the closed state) of the motorcycle. [Fig. 7] Fig. 7 is a sectional view of the seat spring structure (the seat in the open state) of the motorcycle and the electrical component in an assembled state.

[Fig. 8] Fig. 8 is a sectional view and a plan view illustrating the seat spring structure (the seat in the open state) of the motorcycle.

[Fig. 9] Fig. 9 is a perspective view of the seat spring structure of the

motorcycle viewed from one direction.

[Fig. 10] Fig. 10 is a perspective view of the seat spring structure of the motorcycle viewed from the other direction.

[Fig. 1 1] Fig. 11 is a front view illustrating the vehicle-body-side hinge in the seat spring structure of the motorcycle.

Description of Embodiments

The following describes an embodiment of the present invention in detail with reference to the accompanying drawings.

A seat spring structure for a motorcycle according to an embodiment is applied to a scooter-type motorcycle including a step floor as illustrated in Fig. 1. A seat 1 , seat support frames 10, a meter 1 1 , a meter cover 12, a headlight cover 13, a headlight 14, a pair of right and left headlight side covers 15, right and left front blinkers 33 provided on the right and left of the right and left headlight side covers, and a headlight guard 16 rotate integrally with a handle bar 32, and are mounted integrally around a pair of right and left front forks 39 that supports a front wheel 35. Unlike a typical scooter structure, in which components around the front forks 39 are covered by front and rear covers, the motorcycle is structured to have a coverless-motorcycle image. This structure, and an under-seat open space described below, can give an impression of a naked scooter.

In particular, by disposing the pipe-like headlight guard 16 under the headlight 14 from the sides toward the front as well as exposing the seat support frames 10, which are formed with rounded pipes having a diameter larger than typical one, under the seat 1 to the sides, the entire design gives a highly comprehensive impression of a naked scooter. Note that the seat- side weight is heavier than that of a typical seat because the diameter of the pipes is increased. In addition, with an inner upper cover 18 behind the front forks 39, right and left upper leg shields 17 extending on the right and left of the inner upper cover, an inner cover 19

continuous under the inner upper cover, and a leg shield 21 disposed in front of the inner cover, a cover structure that has the function of the leg shield can be provided, as in a typical scooter, even though the components around the front forks are not covered.

Provided behind the inner cover is a step floor 20, and a portion under the step floor is covered by a lower cover 22. On the left side of the lower cover, a side stand 23 is disposed. In a vehicle body frame behind the side stand, a unit swing mechanism that incorporates an engine on the front side and supports a rear wheel 36 on the rear side is supported by a rear suspension 28 in a vertically swingable manner. The structure including the step floor and the unit swing mechanism is a typical scooter structure. The unit swing mechanism includes, for example, a maim stand 24 under the unit, a belt converter case 25 provided on the left side that also serving as a swing arm and shifts the driving force of the engine and transmits the resultant power to the rear wheel, an inner rear fender 26 that covers an upper half of the rear wheel to prevent mud or water from entering an under-seat open space, and an air cleaner 27 provided above the belt converter case and connected to the engine. A portion above the rear suspension 28 and around the seat is provided with a pair of right and left rear side covers 29, a tail light 30 behind the rear side covers, right and left rear blinkers 34 under the tail light, a rear grip 31 a passenger on the rear seat can grip, and a pillion step 38.

In addition, the motorcycle according to the present embodiment has, as illustrated in Figs. 1 and 2, an under-seat open space S that is provided under the seat 1 and is visible through right and left opening parts K on the sides of the vehicle body. The under-seat open space S is formed of a space under the seat 1 that can accommodate baggage, and is visible from the sides through the opening parts K and opens toward the step floor 20 on the front. This structure can give an appearance impression of a fewer covers (that is, a naked feel). The applicant of the present application has created this structure that significantly changes an image of scooters, in which the components under the seat are covered in many cases.

Reference sign 37 indicates hooks for catching baggage accommodated in the under-seat open space S. A total of four hooks, two each for front and rear corners in the space, are provided, so that baggage can be stably fixed in the space under the seat using a net or the like, while creating a naked feel.

The seat 1 is retained by a hinge structure provided to a side of the vehicle body of the motorcycle (on the right side of the running direction in the present embodiment) and provided to a right seat support frame 10. The seat is openable toward a side. The driver can sit on the seat in the closed state. By swinging the entire seat 1 toward the side and opening the under- seat open space S upward, large baggage can be accommodated. The seat 1 in the closed state can be locked on the vehicle body side by a seat catch part b retained by a left seat support frame 10. It should be noted that, even when the seat is in the closed state, small baggage and others can be put in or out through right, left, and front openings.

The seat support frames 10 include, as illustrated in Fig. 3, right and left pipe frames formed integrally with the seat 1 , and a pair of right and left elastic members 42. The elastic members 42 can come into contact with a frame or the cover (contact parts 40a in a first side cover 40 in the present embodiment) on the vehicle body side when the seat 1 is in the closed state. The pipe frames include a pair of pipe members extending in the front and rear directions. The pair of pipe frames are integrally coupled with the lower portion of the seat 1. Two frame members D are positioned on the inner side of the contact parts 40a. The frame members D extend upward from a cross pipe C that connects between a pair of right and left seat frame parts B. Thus, the frames receive the seat weight on the contact parts 40a. In this structure, the seat weight is supported at the following four positions: the pair of right and left contact parts 40a, the hinge structure, and the seat catch part b.

A floor under seat cover Kl covers over the seat frame part B and the cross pipe C. A first side cover 40 integrated with a second side cover 41 following a lower part of the first side cover 40 covers each lateral side of the seat frame part B and the cross pipe C. A battery cover K2 that covers a battery with a fuse box E and an electrical component I, such as an ECU (refer to Figs. 5 and 7), installed in the motorcycle, and a manual cover K3 that covers a space for accommodating tools or the like are attached to the floor under seat cover Kl . By swinging the seat 1 into the open state, the battery cover K2 and the manual cover K3 can be exposed outside, hi the present embodiment, as illustrated in Fig. 5, the floor under seat cover Kl is integrally formed with a battery box accommodating therein the battery with the fuse box E.

The seat spring structure for the motorcycle according to the present embodiment includes, as illustrated in Figs. 4 to 1 1 , a seat hinge structure openably retaining the seat 1 , on which a driver can sit, to a vehicle body with hinge shafts (a front hinge shaft hi and a rear hinge shaft h2 positioned coaxially), an open-seat retainer structure included in the seat hinge structure and including a seat opening spring 5 capable of retaining the seat 1 at a seat open position in an open state and applying biasing force to a cam structure 6 and a cam 7, and a closing-seat damper spring 8 included in the seat hinge structure and applying biasing force in a seat opening direction. The open-seat retainer structure (the cam structure 6, the cam 7, the seat opening spring 5, and a cover part g) is provided to one side (front side) of the hinge shaft (the front hinge shaft hi or the rear hinge shaft h2) in the axial direction thereof. The closing- seat damper spring 8 is provided, separately from the hinge shaft, to the other side (rear side) of the hinge shaft in the axial direction thereof and is fitted to a spring stay 9 that is attachable to and detachable from the seat hinge structure. In other words, the seat 1 is swingable about the front hinge shaft hi and the rear hinge shaft h2 in the seat hinge structure toward the right of the vehicle body and to be in the closed state (refer to Figs. 5 and 6) or the open state (refer to Figs. 7 and 8).

More specifically, as illustrated in Fig. 4, the seat hinge structure according to the present embodiment includes a vehicle-body-side hinge 2 and a seat-side hinge 3 for retaining the seat 1 openable toward a side. The seat-side hinge 3 includes two arms (a front arm 3 a and a rear arm 3b) in the front and rear directions of the vehicle body. The seat opening spring 5 in the seat-side hinge 3 is disposed near the front arm 3a, and the closing-seat damper spring 8 in the vehicle-body-side hinge 2 is disposed near the rear arm 3b. The cam structure 6 including a contact surface 6a and a latch part 6b is swingably mounted on the front arm 3a with a shaft member h3. The rear arm 3b includes a latch part P 1 protruding inwardly (toward the front arm 3a). Furthermore, the two arms (the front arm 3a and the rear arm 3b) of the seat-side hinge 3 each have a protrusion a toward the outside (right side) of the vehicle body with respect to the hinge shafts hi and h2, as illustrated in Figs. 4, 9, and 10, for example. The protrusion a comes into contact with a pin member 2b provided to the vehicle-body-side hinge 2 (refer to Figs. 7, 8, and 1 1) when the seat 1 is opened at a certain angle.

The vehicle-body-side hinge 2 includes, as illustrated in Figs. 4 and 1 1 , a U-shaped stay 4, the seat opening spring 5 (open-seat retainer structure), the cam structure 6 (including the cover part g), the cam 7, the closing-seat damper spring 8, and the spring stay 9. The cam 7 is integrally formed with a front wall part 4a of the U-shaped stay 4. The cam 7 and a rear wall part 4b of the U-shaped stay 4 form a U shape opening upward. The U-shaped stay 4 has a notch 2a at a position, to which a stopper cam part 9b contacts by clockwise turning force generated by fastening the mounting bolt Bl , causing the axial line of a pipe frame part 9a of the spring stay to be coaxial and parallel to the hinge shafts (hi and hi). The single pin member 2b bridging the wall parts 4a and 4b under the hinge shafts (hi and h2) along the front and rear direction of the vehicle body is welded to the wall parts 4a and 4b so as to be parallel to the hinge shafts (hi and h2). A pair of protruded bolt parts P3 provided with male screws are formed on a front and a rear parts in the U-shaped stay 4. The bolt parts P3 are inserted in insertion holes defined in a bracket A welded and fixed to the outer surface of the right seat frame of the vehicle body, and then fastened with nuts N2. Thus, the U-shaped stay 4 is attached to the vehicle body side. The actual structures of the seat-side hinge and the vehicle- body-side hinge are attached to the bracket A after the U-shaped stay is integrated with the seat-side hinge because the hinge shafts hi and h2 are inserted to the arms 3 a and the wall parts 3b, and the flanges and the opposite ends of the hinge shafts hi and h2 are riveted to integrate the structures.

The seat opening spring 5 is a coil spring that has one end 5a and the other end 5b. One end 5a is latched onto the latch part 6b of the cam structure 6, and the other end 5b is latched onto and fitted to a hole in a latch part P2 provided to the U-shaped stay 4. The cam 7 is integrally provided to the wall part 4a in one end side (front side of the vehicle body) of the U-shaped stay 4. The cover part g made of resin or plastic is mounted on a surface of the cam 7 and has a cam surface gl having the same shape as the cam profile of the cam 7 convexing upward. A contact surface 6a of the cam structure 6 makes contact with the cam surface gl of the cam 7 and slides thereon during the opening and closing of the seat 1. In this structure, the seat opening spring 5 applies biasing force to the contact surface 6a in a pressing direction to the cam surface gl . The contact surface 6a gets over the convexed apex on the cam profile at a position where the seat opens at predetermined angles. When the seat is further opened, the contact surface 6a stops the seat at a position that causes protrusions a formed on the arms 3 a, 3b to abut on the pin member 2b. Since the cam surface gl has the cam profile convexing upward, the contact surface 6a needs to get over the ridge on the cam profile again in order to close the seat. The seat therefore keeps the retained state at the position by applying the biasing force of the seat opening spring to a slope on the cam profile through the contact surface 6 a.

The closing-seat damper spring 8 is a torsion spring that has one end 8a and the other end 8b. One end 8a is hooked to the latch part P I (pin) provided to the seat-side hinge 3, and the other end is hooked and fitted to the pin member 2b provided to the vehicle-body-side hinge 2. In this structure, the closing-seat damper spring 8 applies biasing force to the seat 1 in the opening direction. The seat 1 is closed against the biasing force, and accordingly the swinging speed and the load in the closing direction that may be increased by the weight of the seat after the contact surface 6a gets over the ridge on the cam profile can be reduced and impact when the seat is closed can be absorbed. The closing-seat damper spring 8 is retained by the pipe frame part 9a of the spring stay 9. The spring stay 9 includes the pipe frame part 9a that retains the closing-seat damper spring 8, a stopper cam part 9b abuttable on the notch 2a defined in the vehicle-body-side hinge 2, and an insertion hole 9c through which a mounting bolt B l is insertable (refer to Fig. 4). The spring stay 9 is bolted with the mounting bolt B l while being positioned with the stopper cam part 9b abutted on the notch 2a. In other words, after the coil part of the closing- seat damper spring 8 is inserted in the pipe frame part 9a, the stopper cam part 9b is abutted on the notch 2a defined in the U-shaped stay 4 to be positioned by being pressed against a rim, and then the mounting bolt B l is inserted in the insertion hole 9c. Thus, the spring stay 9 is bolted and mounted (even if there is a gap between the stopper cam 9b and the notch 2a, the stopper cam 9b abuts on the notch 2a automatically by the tightening force generated by the bolt).

The pipe frame part 9a according to the present embodiment is provided coaxially with the hinge shaft (the front hinge shaft hi and the rear hinge shaft h2) for the seat 1 , and supports the closing-seat damper spring 8 in a cantilever manner at the front side of the vehicle body. As Fig. 1 1 illustrates, the pipe frame part 9a has a length of about two-thirds of the total length of the closing-seat damper spring 8 and secures a clearance to the rear wall part 4b, the length of the clearance being one-thirds of the total length of the closing-seat damper spring 8. This configuration allows a part of the closing-seat damper spring 8 having no frame part to be deformed when one end 8a of the closing-seat damper spring 8 is hooked on the pin P I , thereby providing an effect of facilitating the assembling and disassembling. Furthermore, in the present embodiment, the mounting bolt B l for the spring stay 9 mounts the spring stay 9 to the vehicle-body-side hinge 2 at a substantially center part of the U-shaped stay 4. In the insertion hole 9c, through which the mounting bolt B l is inserted, in the U-shaped stay 4, as illustrated in Fig. 4, a weld nut l is welded and fixed. Thus, the spring stay 9 can be easily mounted with the mounting bolt B 1.

Furthermore, as illustrated in Fig. 5, the seat hinge structure according to the present embodiment retains the seat 1 in such a manner as to be openable toward a side, and is mounted outside one seat frame part B provided under the seat 1. The electrical component I as an ECU unit is mounted on the inner side of the seat frame part B. The closing-seat damper spring 8 and the ECU unit I are covered with a common cover (in the present embodiment, the floor under seat cover Kl). Since a naked-type scooter having an under-seat open space with open sides under a seat has a limited storage behind the space, the surface of The ECU unit I having the largest area is directed to a lateral side of the vehicle and the unit is inclined and mounted on the vehicle so that the lower part of the unit is disposed under the seat frame part B. This configuration can reduce the height in the vertical direction and make the outer cover small. In the ECU unit I, the battery and the fuse box E are disposed. In the present embodiment, the floor under seat cover is integrally formed with a battery box storage as the common cover, thereby reducing the number of the components. In addition, the maintenance of the hinge part requires the removal of a single cover, thereby facilitating the maintenance.

According to the present embodiment, the open-seat retainer structure including the seat opening spring 5 is provided to one side of the hinge shaft (the front hinge shaft hi and the rear hinge shaft h2) in the axial direction thereof, and the closing-seat damper spring 8 is provided, separately from the hinge shaft, to the other side of the hinge shaft in the axial direction thereof and is fitted to the spring stay 9 that is attachable to and detachable from the seat hinge structure. Thus, the structure can be easily assembled and disassembled.

Furthermore, because the closing-seat damper spring 8 is disposed in the space of the hinge shaft on the side opposite to the stopper structure including the seat opening spring 5, a seat spring structure that has few spatial limitations in the layouts of the both can be provided. In addition, the closing-seat damper spring 8 can be easily employed, which facilitates general application of this structure to various types of motorcycles. The structure thus provided has commercial advantages of requiring reduced power for opening and closing the seat and absorbing the opening and closing speed of the seat 1.

The seat hinge structure according to the present embodiment includes the vehicle- body-side hinge 2 and the seat-side hinge 3. The spring stay 9 includes the pipe frame part 9a that retains the closing-seat damper spring 8 and the stopper cam part 9b abuttable on the notch 2a defined in the vehicle-body-side hinge 2. The spring stay 9 is bolted while being positioned with the stopper cam part 9b abutted on the notch 2a. One end 8 a of the closing- seat damper spring 8 is hooked to a pin provided to the seat-side hinge 3, and the other end of the closing-seat damper spring 8 is hooked to the vehicle-body-side hinge 2. In this structure, the stopper cam part 9b in the spring stay 9 is hooked to the notch 2a in the vehicle-body-side hinge 2, providing a rotation-stopper function, and thus the closing-seat damper spring can be easily positioned accurately, and the structure can be easily assembled and disassembled for maintenance.

Furthermore, the seat hinge structure according to the present embodiment retains the seat 1 in such a manner as to be openable toward a side, and is mounted outside one seat frame part B provided under the seat 1. The electrical component I is mounted on the inner side of the seat frame part B. The closing-seat damper spring 8 and the electrical component I are covered by the common cover (floor under seat cover Kl ). This structure provides good appearance and can reduce the number of parts required.

Furthermore, the seat hinge structure according to the present embodiment includes the seat-side hinge 3 and the vehicle-body-side hinge 2 for retaining the seat 1 in such a manner as to be openable toward a side, and the seat-side hinge 3 includes the two arms (the front arm 3a and the rear arm 3b) in the front and rear directions of the vehicle body. The vehicle-body- side hinge includes a U-shaped stay that supports the two arms on a front wall part and a rear wall part with the hinge shafts. The seat opening spring 5 is disposed near the front arm 3 a, and the closing-seat damper spring 8 is disposed near the rear arm 3b. The mounting bolt B l for the spring stay 9 mounts the spring stay 9 to the vehicle-body-side hinge 2 at a

substantially center part of the U-shaped stay 4. In this structure, the seat opening spring 5 and the closing-seat damper spring 8 will not hamper the fastening or removal of the mounting bolt.

In particular, the two arms (the front arm 3 a and the rear arm 3b) of the seat-side hinge

3 each have the protrusion a. The vehicle-body-side hinge 2 includes the pin member 2b with which the protrusion a comes into contact when the seat 1 is opened at a certain angle, and the other end 8b of the closing-seat damper spring 8 is hooked to the pin member 2b. In this structure, the closing-seat damper spring 8 is disposed near the pin member 2b, and thus the hooking part of the other end 8b of the closing-seat damper spring 8 can be made short. In addition, the pin member 2b can serve as both a stopper for the seat 1 at the open position and a hook for the other end of the closing-seat damper spring 8, which eliminates the need for any special member for these purposes.

Furthermore, the pipe frame part 9a is provided coaxially with the hinge shaft (the front hinge shaft hi and the rear hinge shaft h2) for the seat 1 , and supports the closing-seat damper spring 8 in a cantilever manner at the front side of the vehicle body. With this structure, the closing-seat damper spring can be desirably operated, and the closing-seat damper spring 8 can be easily fitted and removed for maintenance.

Furthermore, the seat 1 includes the seat support frames 10 that retain the seat 1 , and the seat support frames 10 are coupled with the seat hinge structure. A part of the seat support frames 10 is exposed outside. The structure has an under-seat open space S with open sides under the seat 1. In such a motorcycle that has the under-seat open space S and exposes a part of the seat support frame 10 outside, thereby having an intensive impression of the naked feel, even when the weight of the seat 1 increases with larger-diameter seat support frames 10 to further enhance the naked feel, the seat 1 can be popped up when opened by the action of the closing-seat damper spring 8, which reduces power required for operating the seat 1 in the opening direction. Furthermore, when the seat 1, which has been retained and tightened by the seat opening spring 5, is being closed, the speed of the seat in the closing direction can be absorbed by the closing-seat damper spring 8, which facilitates the opening and closing of the seat 1 in the motorcycle with larger-diameter seat support frames 10.

While the present embodiment has been described, the present invention is not limited to the description above. For example, the present invention can be applied to a motorcycle that has no under-seat open space S under the seat 1, and to a motorcycle that gives no naked- feel impression with its seat support frames 10 not exposed outside. In addition, the seat opening spring 5 can be any spring other than the coil spring as long as it can retain the seat 1 at the seat open position in the open state and apply biasing force to the cam structure 6 and the cam 7. The closing-seat damper spring 8 can be any spring other than a torsion spring as long as it can apply biasing force to the seat in the opening direction.

Industrial Applicability

The open-seat retainer structure is applicable to seat spring structures for motorcycles with different external shapes or different functions as long as they are seat spring structures for motorcycles in which an open-seat retainer structure is provided to one side of a hinge shaft in the axial direction thereof, and a closing-seat damper spring is provided, separately from the hinge shaft, to the other side of the hinge shaft in the axial direction thereof and is fitted to a spring stay that is attachable to and detachable from a seat hinge structure.

Reference Signs List

1 seat

2 vehicle-body-side hinge

2a notch

2b pin member

3 seat-side hinge

4 U-shaped stay

5 seat opening spring (open-seat retainer structure)

6 cam structure 7 cam

8 closing damper spring

9 spring stay

9a pipe frame

9b stopper cam part

10 seat support frames hi front hinge shaft h2 rear hinge shaft

S under-seat open space K opening part

Claims

16 CLAIMS

1. A seat spring structure for a motorcycle comprising:

a seat hinge structure openably retaining a seat, on which a driver is capable of sitting, to a vehicle body with at least one hinge shaft;

an open-seat retainer structure included in the seat hinge structure and including a seat opening spring capable of retaining the seat at a seat open position in an open state and applying biasing force to a cam structure and a cam; and

a closing-seat damper spring included in the seat hinge structure and applying biasing force in a seat opening direction, wherein

the open-seat retainer structure is provided to one side of the hinge shaft in an axial direction thereof, and the closing-seat damper spring is provided, separately from the hinge shaft, to another side of the hinge shaft in the axial direction thereof and is fitted to a spring stay that is attachable to and detachable from the seat hinge structure.

2. The seat spring structure for the motorcycle according to claim 1 , wherein the seat hinge structure includes a vehicle-body-side hinge and a seat-side hinge; the spring stay includes a pipe frame part that retains the closing-seat damper spring and a stopper cam part abuttable on a notch defined in the vehicle-body-side hinge, the stopper cam part being bolted in a state in which the stopper cam part is abutted and positioned on the notch; and one end of the closing-seat damper spring is hooked to a pin provided to the seat-side hinge, and another end of the closing-seat damper spring is hooked to the vehi cle-body-side hinge.

3. The seat spring structure for the motorcycle according to claim 1 , wherein the seat hinge structure retains the seat openable toward a side, and is mounted outside one seat frame part provided under the seat; an electrical component is mounted on an inner side of the seat frame part; and the closing-seat damper spring and the electrical component are covered with a common cover.

4. The seat spring structure for the motorcycle according to claim 2, wherein the seat hinge structure includes the seat-side hinge and the vehicle-body-side hinge for retaining the seat openable toward a side; the seat-side hinge includes two arms in front and rear directions of the vehicle body; the vehicle-body-side hinge includes a U-shaped stay that supports the two arms on a front wall part and a rear wall part with the hinge shafts; the seat opening spring 17 is disposed near the front arm, and the closing-seat damper spring is disposed near the rear arm; and a mounting bolt for the spring stay mounts the spring stay to the vehicle-body-side hinge at a substantially center part of a U-shaped stay.

5. The seat spring structure for the motorcycle according to claim 4, wherein the two arms of the seat-side hinge each have a protrusion, the vehicle-body-side hinge includes a pin member with which the protrusion comes into contact when the seat is opened at a certain angle, and the other end of the closing-seat damper spring is hooked to the pin member.

6. The seat spring structure for the motorcycle according to claim 2, wherein the pipe frame part is provided coaxially with the hinge shaft for the seat, and supports the closing-seat damper spring in a cantilever manner at a front side of the vehicle body.

7. The seat spring structure for the motorcycle according to claim 1 , wherein the seat includes a seat support frame that retains the seat, the seat support frame is coupled with the seat hinge structure, a part of the seat support frame is configured to be exposed outside, and the seat spring structure has an under-seat open space with open sides under the seat.