JP5150372B2 - Rear structure of the vehicle - Google Patents

Description

  The present invention relates to a rear structure of a vehicle provided with a rear cushion unit.

Usually, a front suspension that supports the front wheels is provided at the front of the vehicle, and a rear suspension that supports the rear wheels is provided at the rear of the vehicle.
A front suspension and a rear suspension provided at the front and rear of the vehicle have a function of reducing the impact received by the front and rear wheels from the road surface during traveling.

By the way, when a brake is applied during driving, if a load is applied to the front of the vehicle due to the inertial force of the vehicle and the occupant, a so-called nose dive phenomenon occurs in which the front suspension is compressed and the vehicle leans forward. There are things to do. The vehicle nose dive phenomenon during braking is preferably avoided or suppressed as much as possible in order to ensure good maneuverability.
Therefore, a technique for avoiding or reducing the nose dive phenomenon of the vehicle is known (for example, see Patent Document 1).
JP-A-8-26169 (FIG. 3)

  In FIG. 3 of Patent Document 1, an inner tube 21 is slidably fitted into an outer tube 22 in a front fork 20 as a front suspension. A guide spacer 38 is provided in the lower end portion of the inner tube 21, a joint spacer 41 is provided on the guide spacer 38 via a spring 47 so as to be slidable up and down, and a spring 48 is provided on the joint spacer 41. Is divided into an oil chamber 43 in the guide spacer 38 and an oil chamber 44 other than that, and a communication passage 46 having an opening 45 in the guide spacer 38 and communicating between the oil chamber 43 and the oil chamber 44 is formed. The oil passage opening and closing device 50 that blocks the oil 45 between the oil chamber 43 and the oil chamber 44 by closing the opening 45 in the oil chamber 43. It is provided. The oil passage opening / closing device 50 is connected to the front brake device.

When the front brake device is operated, the movement of oil between the oil chamber 43 and the oil chamber 44 is prevented in conjunction with this operation, so that the spring 47 disposed below the joint spacer 41 does not contract. The spring 48 disposed above the joint spacer 41 can be expanded and contracted to increase the spring constant of the front fork.
That is, during normal driving, the spring constant of the front fork is set to an appropriate value, and the spring constant is increased only when a brake operating force exceeding a predetermined level is applied, thereby suppressing the nose dive phenomenon of the vehicle.

By the way, as a measure for suppressing the nose dive phenomenon, there is a method for the rear suspension (rear cushion unit) provided at the rear part of the vehicle body as well as for the front fork provided at the front part of the vehicle body as in Patent Document 1. Conceivable.
The technique of Patent Document 1 does not disclose measures for the rear part of the vehicle body.

  It is an object of the present invention to provide a vehicle body rear portion structure that can suppress a nose dive phenomenon of a vehicle during braking.

The invention according to claim 1 is a vehicle body frame, a swing arm that is pivotally supported by the vehicle body frame and supports a rear wheel, a rear cushion unit provided between the swing arm and the vehicle body frame, A brake master cylinder that is provided on the frame and generates hydraulic pressure when the rear brake pedal is operated, and the rear cushion unit includes a cylinder that is filled with damper oil, and a cylinder that is reciprocally stored in the cylinder. A piston that is divided into one chamber and the other chamber, a rod that extends from the piston and is connected to the other of the vehicle body frame and the swing arm, and damper oil that is provided on the piston from one chamber to the other chamber In the rear structure of a vehicle provided with a rear unit comprising an orifice to be passed The rod is provided with a through hole consisting of a small-diameter part, a step part, and a large-diameter part in the axial direction, and when the tip approaches the step part, a throttling action is generated, and one chamber goes to the other chamber or one from the other chamber. A brake oil hydraulic chamber that inserts a flow control rod that controls the flow rate of the damper oil that moves into the chamber into the large-diameter part, and stores brake oil that pushes the rear end face of the flow control rod on the rear end side of this flow control rod The first hydraulic line is extended from the brake oil hydraulic chamber, the tip of the first hydraulic line is connected to the master cylinder, and a cylindrical member is inserted into the large diameter portion. The inside constitutes a small diameter portion, and one end of the cylindrical member constitutes a step portion .

  In the invention according to claim 2, a joint member for branching the brake oil supplied from the master cylinder is interposed in the middle of the first hydraulic line, and the second hydraulic line extends from the branch port of the joint member. The tip of the second hydraulic pipe is connected to a rear brake caliper.

  The invention according to claim 3 is characterized in that the joint member is provided with a shut-off valve capable of shutting off the flow of the brake oil to the brake oil hydraulic pressure chamber.

  The invention according to claim 4 is characterized in that the flow rate control rod includes an urging member that prevents the tip from approaching the stepped portion.

  In the invention according to claim 5, the urging member is a return spring, and the return spring is interposed between a flange portion attached to the flow rate control rod and a spring seat provided on the rod. It is characterized by.

  In the first aspect of the invention, the rod provided in the rear cushion unit is provided with a through hole, and a flow control rod for controlling the flow rate of the damper oil is inserted into the through hole, and the brake control brake is disposed at the rear end side of the flow control rod. An oil hydraulic chamber was provided, the first hydraulic line was extended from the brake oil hydraulic chamber, and the tip of the first hydraulic line was connected to the master cylinder.

  By the pedal operation of the rear brake pedal, the hydraulic pressure is transmitted through the first hydraulic line, and the hydraulic pressure in the brake hydraulic pressure chamber becomes high. The brake oil that has become high pressure in the brake oil hydraulic chamber pushes the rear end face of the flow control rod, and the flow rate of the damper oil that moves from one chamber to the other chamber or from the other chamber to one chamber is regulated. . When the flow rate of the damper oil is restricted, the function (damping force) for attenuating vibration energy and the like of the rear cushion unit is enhanced.

  When the damping force of the rear cushion increases, the speed at which the rear cushion tries to extend can be reduced when the brake is applied. If the speed at which the rear cushion extends is slowed, the speed at which the rear part of the vehicle body rises during braking can be slowed, and the nose dive phenomenon of the vehicle can be suppressed.

  Further, the rear structure of the vehicle body of the present invention includes a through hole formed in the rod, a flow control rod inserted into the through hole, a brake oil hydraulic chamber for pressing the flow control rod, the brake oil hydraulic chamber and the master. A first hydraulic line that connects the cylinder is provided.

With such a configuration, the basic configuration of the rear cushion unit is not significantly changed, and can be implemented only by a small modification of the existing rear cushion unit. Therefore, the apparatus can be configured easily and at low cost.
Further, a cylindrical member is inserted into the large diameter portion, the hollow inside of the cylindrical member constitutes a small diameter portion, and one end of the cylindrical member constitutes a stepped portion.
By replacing the cylindrical member with a cylindrical member having a hollow interior having a different inner diameter, the opening area of the hollow interior can be changed. If the opening area inside the hollow changes, the damping characteristic of the rear cushion changes. If the damping characteristic of the rear cushion can be changed, the optimum damping characteristic can be easily obtained.

  In the invention according to claim 2, a joint member is interposed in the middle of the first hydraulic pipe line, and the second hydraulic pipe line that connects the rear brake caliper is provided in the joint member. Yes.

  The moving mechanism of the flow control rod is also used as the master cylinder that operates the rear brake. Since the rear brake is operated and the damping force of the rear cushion is adjusted with only one master cylinder, the rear structure of the vehicle can be configured easily and at low cost.

  In the invention according to claim 3, since the shutoff valve is provided in the joint member, the damping force variable mechanism of the rear cushion is blocked by shutting off the flow of the brake oil to the brake oil hydraulic pressure chamber with this shutoff valve. Can be easily put into a non-use state.

  In the invention which concerns on Claim 4, the flow control rod is provided with the biasing member which prevents that a front-end | tip approaches the step part. After the flow control rod is moved by the brake oil pressure, when the brake operation is released, the flow control rod is returned to the original position by the damper oil pressure. It becomes possible to return to the original position, and the damping force can be returned to the original.

  In the invention according to claim 5, the urging member is a return spring, and this return spring is interposed between the flange portion of the flow control rod and the spring seat of the rod, and is limited in a limited space. Can be provided. With such a configuration, an increase in size of the rear cushion unit can be avoided.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a left side view of a motorcycle according to the present invention. A motorcycle 10 as a vehicle includes a head pipe 11, a steering shaft 12 penetrating the head pipe 11, and upper and lower ends of the steering shaft 12. A front fork 15 that supports the steering handle 13 and the front wheel 14 attached to each other, and a pair of left and right main frames 17L and 17R as components of the vehicle body frame 16 extending rearward from the head pipe 11 (only reference numeral 17L on the front side in the figure is shown). The same shall apply hereinafter), an engine 18 suspended on the left and right main frames 17L, 17R, a pivot shaft 19 spanning the rear of the left and right main frames 17L, 17R, and a main frame 17L extending rearward from the pivot shaft 19 , 17R, a swing arm 22 that is pivotally supported to support the rear wheel 21, and the swing Over arm 22 and the main frame 17L, and the rear cushion unit 23 provided between the 17R, are provided.

  Further, steps 25L and 25R (only 25L on the front side of the figure) on which the occupant puts his / her feet through the step brackets 24L and 24R (only the front side 24L is shown) are provided on the rear portions of the main frames 17L and 17R. Is provided.

  The engine 18 includes a crankcase 31, a crankshaft 32 provided in the crankcase 31, a front cylinder 33 </ b> F that extends obliquely forward and upward from the crankcase 31 with the crankshaft 32 as the shaft center, and a rearward and upward extension A cylinder 33R, an intake device 34 attached between the front cylinder 33F and the rear cylinder 33R, a front exhaust device 35F attached to the front portion of the front cylinder 33F, a rear exhaust device 35R attached to the rear portion of the rear cylinder 33R, A transmission 36 provided integrally with the crankcase 31 is provided behind the crankshaft 32. Reference numeral 37 denotes an oil pan.

  The transmission 36 is provided with an output shaft 41 projecting sideways, a drive sprocket 42 is attached to the output shaft 41, and a driven sprocket 43 is integrally attached to the rear wheel 21. A chain 44 is spanned between the sprocket 42 and the driven sprocket 43.

  In the figure, 45a and 45b are first and second radiators disposed in front of the engine 18, 46 is a battery disposed below the second radiator 45b, 47 is a fuel tank, and 48 is fuel built in the fuel tank 47. Pump unit, 51 cowling, 52 windscreen, 53 front fender, 54 seat cowl, 55 seat mounted on the seat cowl, 56 front wheel disc brake unit, 57 rear disc brake unit, 58 engine A control unit 59 is a rear fender.

  FIG. 2 is a side view of the right main part of the motorcycle according to the present invention. Fastening members 61 and 61 are provided at the rear of main frames 17L and 17R (only the reference numeral 17R on the front side) as the rear structure 60 of the vehicle. A front portion of a step bracket 24R formed so as to have a U-shape when viewed from the side and arranged so as to open a front-facing character is attached to the rear portion of the step bracket 24R. A rear brake pedal 62 is provided projecting outward and swingable about the step 25R. When the rear brake pedal 62 is operated above the step bracket 24R as a component of the vehicle body frame 16, the rear brake pedal 62 is operated. A brake master cylinder 63 (master cylinder 63) that generates hydraulic pressure is attached.

A connecting member 64 is interposed between the rear brake pedal 62 and the brake master cylinder 63 to transmit the stepping force applied to the rear brake pedal 62 to the brake master cylinder 63.
An oil cup 65 is attached to the upper part of the master cylinder 63 and stores brake oil. The detailed structure of the master cylinder 63 will be described later.

  A rear cushion unit 23 is disposed inside the step bracket 24R, the brake master cylinder 63, and the rear brake pedal 62, and a sub tank 67 for storing excess damper oil is integrally attached to the upper portion of the rear cushion unit 23. Yes.

  The upper end portion of the rear cushion unit 23 is attached to the main frames 17L and 17R, and the lower end portion of the rear cushion unit 23 is attached to the swing arm 22 via the link mechanism 71, and an impact (shock) applied to the swing arm 22 is applied. ).

  The link mechanism 71 includes a first arm 73 having a triangular shape in side view and having first to third nodes 72 a to 72 c, and a second arm 74 spanned between the first arm 73 and the swing arm 22. The main component. Here, the first joint 72a is attached to the first shaft 70a spanning the main frames 17L and 17R, the second joint 72b is attached to the lower end of the rear cushion unit 23, and the third joint 72c is the second arm 74. Attached to.

  FIG. 3 is a system diagram of the anti-nose dive mechanism provided in the rear structure of the vehicle according to the present invention. The main pipe as the first hydraulic line 76 is connected to the brake master cylinder 63 attached to the upper part of the step bracket 24R. A front end portion of the passage 77 is connected, a joint member 78 for branching brake oil is connected to a rear end portion of the main conduit 77, and a first hydraulic conduit connected from the joint member 78 to the rear cushion unit 23. A cushion line 79 as 76 extends, and a second hydraulic line 82 connected to a rear brake caliper 81 provided in the rear wheel disc brake unit 57 extends, and the pressure applied to the rear master cylinder 63 is reduced by the brake. The oil can be transmitted to the rear cushion unit 23 and the rear brake caliper 81.

That is, a joint member 78 that branches the brake oil supplied from the master cylinder 63 is interposed in the middle of the first hydraulic line 76, and the second hydraulic line 82 extends from the branch port 84 of the joint member 78. As a result, the tip of the second hydraulic conduit 82 was connected to the rear brake caliper 81.
Hereinafter, detailed structures of the rear brake master cylinder 63, the rear cushion unit 23, and the joint member 78 will be described.

  FIG. 4 is a cross-sectional view of the brake master cylinder according to the present invention. The brake master cylinder 63 is attached to the upper portion of the step bracket 24R via attachment bolts 85 and 85.

  The brake master cylinder 63 includes a main body portion 87 as a case, a brake piston 89 fitted in a cylinder hole 88 opened in the main body portion 87 so as to be slidable back and forth, and a brake piston 89 provided at a rear portion of the brake piston 89. Push rod 91 provided so as to be able to be pressed forward, a spring 92 provided at the front end portion of the brake piston 89 and urging the brake piston 89 rearward, and oil for storing brake oil attached to the upper portion of the main body portion 87 via a bolt 93 The cup 94 is a main component.

  The cylinder hole 88 and the oil cup 94 communicate with each other through a brake communication hole 95, and the brake oil injected into the oil cup 94 reaches the cylinder hole 88 through the brake communication hole 95. The cylinder hole 88 is filled with brake oil, and an output port 96 that connects the first hydraulic line 76 is provided at the front end of the cylinder hole 88.

  In the figure, 97 is a hook-like stopper for holding the push rod 91 on the main body 87, 98a and 98b are circlips, 99 is a boot covering the rear end of the main body 87, 101 is a first seal, and 102 is a second seal. 103a and 103b are large and small holes that are interposed between the brake communication hole 95 and the cylinder hole 88, and 100 is a cap as a lid.

  FIG. 5 is a sectional view of a rear cushion unit according to the present invention. The rear cushion unit 23 includes a cylindrical upper collar member 111 attached to a vehicle body frame (reference numeral 16 in FIG. 1), and a spherical surface on the upper collar member 111. A damper cylinder 113 that is provided via an upper bearing 112 having a damper and filled with damper oil; and a piston that is reciprocally stored in the damper cylinder 113 and that divides the damper cylinder 113 into one chamber 114 and the other chamber 115. A damper piston 116, a rod 118 extending from the damper piston 116 and connected to the swing arm 22 side, and provided on the damper piston 116 from one chamber 114 to the other chamber 115 or from the other chamber 115 to one Orifices 121 and 121 for allowing damper oil to pass into the chamber 114, and a damper A sub-tank 67 that is attached to the Linda 113 and stores excess damper oil, an adjustment part 124 that can be adjusted around the upper part of the damper cylinder 113, an upper annular part 123 attached to the adjustment part 124, and a lower end part of the rod 118 A hook-like lower annular portion 125 to be attached; a cushion spring 126 provided on the outer side of the damper cylinder 113 between the lower annular portion 125 and the upper annular portion 123; a support member 127 that supports the lower annular portion 125; The support member 127 is provided with a cylindrical lower collar member 129 which is provided via a lower bearing 128 having a spherical surface and attached to a swing arm.

  One chamber 114 and the other chamber 115 of the damper cylinder 113 are both filled with damper oil, and a damper communication path 131 is provided between the sub tank 67 and the one chamber 114, and this damper communication path 131 is provided. The damper cylinder 113 is configured to be filled with damper oil.

  In the rear cushion unit 23 of the present invention, the rod 118 is provided with a through hole 136 composed of a small diameter portion 133, a step portion 134, and a large diameter portion 135 in the axial direction. A flow rate control rod 137 for controlling the flow rate of damper oil moving from one chamber 114 to the other chamber 115 is inserted into the large diameter portion 135 opened in the rod 118, and the damper is communicated from the side to the large diameter portion 135. An opening 173 as a side hole through which oil passes is provided, and a brake oil hydraulic chamber for storing brake oil for pushing the rear end surface 137s of the flow control rod 137 in the support member 127 provided on the rear end side of the flow control rod 137. 138 was provided.

  A relay member 141 is attached to the brake oil hydraulic pressure chamber 138, a connection member 142 is detachably attached to the relay member 141, and a first hydraulic line 76 is attached to the relay member 141. Therefore, the first hydraulic line 76 can be attached to and detached from the brake oil hydraulic pressure chamber 138 quickly and easily.

  An adjustment bolt 144 for adjusting the position of the retracted end of the flow control rod 137 is attached to the support member 127. Reference numeral 145 denotes a small spring interposed between the head of the adjustment bolt 144 and the support member 127, and reference numeral 146 denotes a ball biased by the small spring 145. The ball 146 is engaged with a plurality of grooves 147 provided on the adjustment bolt 144. By combining, the adjustment bolt 144 can be held on the support member 127 while providing a click feeling, and the adjustment work of the adjustment bolt 144 can be easily performed.

  In the figure, 151 is a first stopper for holding the damper piston 116 attached to the rod 118 from one side, 152 is a second stopper for holding the damper piston 116 from the other side, 153 is a rebound seat, 154 is a rebound spring, 155 is a rod guide It is a member.

  Referring also to FIG. 3, the first hydraulic line 76 was extended from the brake oil hydraulic chamber 138. The first hydraulic line 76 includes a cushion line 79 and a main line 77, and is connected in this order from the brake oil hydraulic chamber 138 to the master cylinder 63. That is, the leading end of the main conduit 77 that is the tip of the first hydraulic conduit 76 is connected to the master cylinder 63.

  The moving mechanism 160 of the flow rate control rod 137 is also used by the master cylinder 63 that operates the rear wheel disc brake unit 57. Since the operation of the rear wheel disc brake unit 57 and the adjustment of the damping force of the rear cushion unit 23 are performed with only one master cylinder, the rear structure 60 of the vehicle is configured simply, lightly and at low cost. Can do.

  In the present embodiment, the damper cylinder 113 side is provided on the vehicle body frame 16 side and the rod 118 is provided on the swing arm 22 side, which is a so-called inverted arrangement, but the damper cylinder 113 is provided on the swing arm 22 side. The rod 118 may be provided on the vehicle body frame 16 side.

  The structure and function added to the rear cushion unit 23 may be applied to the front fork. Further, it is possible to use the hydraulic pressure of the front master cylinder used for the front brake instead of the hydraulic pressure of the rear master cylinder 63. In this case, the damping force on the front fork compression side is increased in order to exhibit the action of the anti-nose dive.

FIG. 6 is a configuration diagram and an operation explanatory diagram of the flow rate control rod and its peripheral portion according to the present invention.
In (a1), in the vicinity of the rear end portion of the through hole 136 provided at the center of the rod 118 in the axial direction, a large spring that has a hole diameter wider than the large diameter portion 135 and can accommodate the return spring 163 as the urging member 162. A diameter hole 164 is formed, and a spring seat 165 is provided at the boundary between the spring large diameter hole 164 and the large diameter portion 135.

  In addition, a flange portion 167 that has a bowl shape and contacts the return spring 163 is provided at the rear portion of the flow control rod 137. A return spring 163 is interposed between a flange portion 167 attached to the flow control rod 137 and a spring seat 165 provided on the rod 118. That is, the flow rate control rod 137 is provided with a return spring 163 that prevents the front end portion 137 a from approaching the stepped portion 134.

  In addition, a cylindrical member 171 is inserted in the front portion of the through hole 136, the hollow interior 172 of the cylindrical member 171 forms a small diameter portion 133, and one end 171 a of the cylindrical member 171 forms a stepped portion 134. I did it.

  Here, the opening area of the hollow interior 172 can be changed by replacing the cylindrical member 171 inserted into the through hole 136 with the cylindrical member 171 having the hollow interior 172 having different inner diameters. If the opening area of the hollow interior 172 changes, the damping characteristic of the rear cushion unit 23 changes. If the damping characteristic of the rear cushion unit 23 can be changed, the optimum damping characteristic can be easily obtained.

  The flow control rod 137 has a tip 137 a having a truncated cone shape, and the tip 137 a is opened at the side of the through hole 136 by being close to or separated from the stepped portion 134 and communicated with the other chamber 115. The flow rate of the damper oil that flows through the opening 173 and flows into the one chamber 114 can be changed.

  The rear end surface 137 s of the flow control rod 137 is formed in a conical taper shape. Usually, the flow control rod 137 is urged rearward by the return spring 163, so that the rear end surface 137 s is inclined to the inclined surface 144 s of the adjustment bolt 144. By applying, when the hydraulic pressure exceeding the predetermined value is not applied to the brake oil hydraulic chamber 138, the backward end of the flow control rod 137 can be positioned.

The adjustment bolt 144 is such that the center of the inclined surface 144s is eccentric from the center axis 144J of the adjustment bolt 144.
In (a2), the adjustment bolt 144 was rotated to change the position of the inclined surface 144s. Compared with (a1), the position of the flow rate control rod 137 is the position moved backward. Thus, by rotating the adjustment bolt 144, the position of the flow rate control rod 137 can be adjusted, and the damping characteristic can be adjusted more flexibly. In the figure, 174 is an O-ring.

  In (b), when the brake oil pressure in the brake oil hydraulic pressure chamber 138 reaches a pressure higher than the hydraulic pressure of the damper oil, the flow control rod moves forward against the pressure of the damper oil and the return spring 163. It has been shown.

The flow rate control rod 137 is provided with a return spring 163 as an urging member 162 that prevents the tip from approaching the step portion 134. After the flow control rod 137 is moved by the brake oil pressure, when the brake operation is released, the flow control rod 137 is returned to the original position by the damper oil pressure. It becomes possible to reliably return to the original position, and the damping force can be returned to the original.
The return spring 163 is interposed between the flange portion 167 of the flow rate control rod 137 and the spring receiving seat 165 of the rod 118, and can be provided in a limited space with a simple structure. Therefore, an increase in size of the rear cushion unit 23 can be avoided.

FIG. 7 is a cross-sectional view of the joint member according to the present invention and an operation explanatory view thereof.
In (a), the joint member 78 includes a body portion 176. The body portion 176 has an input port 177 to which the brake oil pressure is input, a first output port 178 and a second output to which the brake oil pressure is output. An opening 179, a first passage 181 extending from the input port 177 to the first output port 178, a branch port 84 provided in the middle of the first passage 181 and branching the brake oil into the second passage 182, and the branch port 84, a second passage 182 extending from the second output port 179 to the second output port 179 is formed, and a screw hole 184 as a blocking hole 183 is formed on the first output port 178 side of the branch port 84. The screw hole 184 is provided with a shut-off valve 185 that can block the flow of the brake oil by closing the first passage 181 so as to be screwed.
In the figure, reference numeral 186 denotes a screw portion provided on the shut-off valve 185, and reference numeral 187 denotes a seal.

  The input port 177, the first output port 178, and the second output port 179 are connected to the main line 77, the cushion line 79, and the second hydraulic line 82 in this order. The road has a detachable structure.

In (b), the state where the shut-off valve 185 is screwed to the forward end is shown.
By screwing the shut-off valve 185 to the forward end and shutting off the flow of brake oil to the brake oil hydraulic chamber (see reference numeral 138 in FIG. 5), a variable damping force mechanism for the rear cushion unit (reference numeral 23 in FIG. 2) is provided. It can also be disabled.

  Since the damping force variable mechanism of the rear cushion unit 23 can be prevented from functioning, the present system can be invalidated according to the road surface condition, the rider's request, and the like.

The operation of the rear structure of the vehicle described above will be described next.
FIG. 8 is an explanatory diagram of the operation of the rear structure of the vehicle according to the present invention. Under the same conditions, the front wheel 14 and the rear wheel 21 function as the front wheel disk brake unit 56 and the rear wheel disk brake unit 57, and full braking is performed. After that, the height of the rear part of the vehicle after a lapse of a predetermined time is compared. In both cases (a) and (b), a force in the contracting direction is applied to the front fork 15 by the inertial force of the vehicle and the occupant, and a force in the extending direction is applied to the rear cushion unit 23.

In (a), an embodiment is shown. The rear cushion unit 23 is slow in extension and slow, and the height of the rear portion of the vehicle after a predetermined time has become Ha.
In (b), a comparative example is shown. Since the rear cushion unit 23B is not provided with a flow rate control rod for controlling the flow rate of the damper oil during braking, the height of the rear portion of the vehicle after a predetermined time has elapsed. Becomes Hb. In (b), as compared with (a), the rear cushion unit 23 extends faster and the height Hb becomes larger.

  That is, the relationship between the heights Ha and Hb of the rear part of the vehicle after a predetermined time has elapsed is Ha <Hb. That is, the nose dive phenomenon is suppressed as a whole vehicle. If the nose dive phenomenon is suppressed, the posture change of the vehicle is suppressed.

The operation of the damping force variable mechanism of the rear cushion unit 23 will be described with reference to FIGS.
When the rear brake pedal 62 is operated, the brake oil pressure is transmitted to the brake oil hydraulic chamber 138 through the first hydraulic line 76, and the hydraulic pressure in the brake oil hydraulic chamber 138 becomes high. When the hydraulic pressure of the brake oil becomes higher than the hydraulic pressure of the damper oil, the brake oil presses the rear end surface 137s of the flow control rod 137 against the force of the return spring 163 and the pressure of the damper oil, The flow rate of the damper oil moving from 114 to the other chamber 115 is restricted. When the flow rate of the damper oil is regulated, the function (damping force) for damping vibration energy and the like increases.

  When the damping force of the rear cushion unit 23 is increased, the speed at which the rear cushion unit 23 extends when the brake is applied can be reduced (slowly). If the speed at which the rear cushion unit 23 extends is slowed down, the speed at which the rear part of the vehicle body rises at the time of braking becomes slow, and the nose dive phenomenon of the vehicle can be suppressed.

  Further, in the present invention, a through hole 136 provided in the rod 118 of the rear cushion unit 23, a flow control rod 137 inserted into the through hole 136, a brake oil hydraulic chamber 138 for pushing the flow control rod 137, The brake oil hydraulic chamber 138 and the first hydraulic line 76 connecting the master cylinder have a relatively simple configuration.

  With such a configuration, there is no significant change in the basic configuration of the rear cushion unit, and therefore it can be implemented only by a small modification of the existing rear cushion unit. Therefore, the apparatus can be configured easily and at low cost.

The flow control rod moving mechanism 160 is also used as the master cylinder 63 for operating the rear wheel disc brake unit 57 as a rear brake. Since the operation of the rear brake and the adjustment of the damping force of the rear cushion are performed with only one master cylinder, the rear structure of the vehicle can be configured simply, lightly and at low cost.
Further, since the flow rate control rod of the rear cushion unit 23 can be controlled without using an expensive electronic control mechanism, the apparatus cost can be reduced also in this respect.

  FIG. 9 is a diagram showing another embodiment of FIG. 7. The first passage 181 has a bent portion 191 at the position of the shutoff valve 185B interposed in the middle thereof, and the upstream side of the bent portion 191 is connected to the first upper passage. 192, when the downstream side of the shut-off valve 185 is the first lower passage 193, the axis 192J of the first upper passage 192 and the axis 185J of the shut-off valve 185 are arranged to coincide.

Regarding the points greatly different from FIG. 7, the shut-off hole 183 </ b> B formed in the body portion 176 is not provided with a screw portion, the shut-off valve 185 </ b> B is not provided with a screw portion, and the head of the shut-off valve 185 </ b> B A spring 195 that urges the shut-off valve 185B toward the input port 177 in the axial direction of the first upper passage 192 is disposed at 185Bh, and a plug member 196 that holds the rear end portion of the spring 195 is disposed.
According to the above configuration, the position of the shutoff valve 185 can be changed depending on the hydraulic pressure of the master cylinder 63. The operation will be described below.

  In (a), the position of the cutoff valve 185B when the hydraulic pressure of the master cylinder 63 input to the input port 177 is smaller than the force urged by the delay spring 195 is shown.

  In this case, the shutoff valve 185 </ b> B is in a position to close the first passage 181, and brake oil does not flow to the first output port 178 of the first passage 181. Therefore, in this case, the hydraulic pressure of the master cylinder 63 is transmitted only to the second output port 179.

In (b), the position of the shut-off valve 185 when the hydraulic pressure of the master cylinder 63 input to the input port 177 is larger than the force urged by the delay spring 195 is shown.
In this case, the shut-off valve 185 moves in the direction of FIG. B, and the brake oil flows to the second output port 179 and the first output port 178. Accordingly, the hydraulic pressure in the master cylinder 63 is transmitted not only to the second output port 179 but also to the first output port 178.

  By changing the characteristics of the spring 195, the characteristics related to the hydraulic pressure action on the first output port 178 can be adjusted. Therefore, the hydraulic fluid pressure of the anti-nose dive mechanism can be set to a desired value.

Although the present invention is applied to a motorcycle in the embodiment, it can also be applied to a tricycle and can be applied to a general vehicle.
It is possible to electronically control the shutoff valve of the joint member with a motor or the like. In this way, it is possible to make changes during traveling.
In claim 1, the joint member may be omitted and a dedicated hydraulic circuit may be provided. In claim 2, it is possible to omit the shut-off valve provided in the joint member.

  The present invention is suitable for the rear structure of a motorcycle.

1 is a left side view of a motorcycle according to the present invention. 1 is a side view of a right main part of a motorcycle according to the present invention. 1 is a system diagram of an anti-nose dive mechanism provided in a rear structure of a vehicle according to the present invention. It is sectional drawing of the brake master cylinder which concerns on this invention. It is sectional drawing of the rear cushion unit which concerns on this invention. It is a block diagram and an operation explanatory view of a flow control rod and its peripheral part concerning the present invention. It is sectional drawing of the joint member which concerns on this invention, and its effect | action explanatory drawing. It is operation | movement explanatory drawing of the rear part structure of the vehicle which concerns on this invention. It is another Example figure of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 16 ... Body frame, 21 ... Rear wheel, 22 ... Swing arm, 23 ... Rear cushion unit, 60 ... Rear part structure of vehicle, 62 ... Rear brake pedal, 63 ... Brake master cylinder, 76 ... First hydraulic line, 78 DESCRIPTION OF SYMBOLS ... Joint member, 81 ... Rear brake caliper, 82 ... Second hydraulic conduit, 84 ... Joint member branch port, 113 ... (damper) cylinder, 114 ... One chamber, 115 ... Other chamber, 116 ... (Damper) ) Piston, 118 ... Rod, 121 ... Orifice, 133 ... Small diameter part, 134 ... Step part, 135 ... Large diameter part, 136 ... Through hole, 137 ... Flow control rod, 137s ... Rear end surface of flow control rod, 138 ... Brake Oil hydraulic chamber, 162 ... biasing member, 163 ... return spring, 165 ... spring seat, 167 ... flange, 171 ... cylindrical member, 1 Hollow interior of 2 ... cylindrical member, 185 ... shutoff valve.

Claims (5)

A body frame (16), and the swing arm (22) that the vehicle body frame (16) swingably supported by rear wheels (21) supporting, with the this swing arm (22) the vehicle body frame (16) A rear cushion unit (23) provided between the vehicle body frame (16) and a brake master cylinder (63) that is provided on the vehicle body frame (16) and generates hydraulic pressure when the rear brake pedal (62) is operated,
The rear cushion unit (23) includes a cylinder (113) the damper is filled with oil, the cylinder (113) reciprocates is freely accommodated in one of said cylinder (113) to the chamber and the other (114) chamber ( a piston (116) be divided into 115), a rod (118) connected to the other of the piston (116) extended from said body frame (16) and said swing arm (22), said piston ( an orifice (121) passing said other chamber (115) to the damper oil from provided said one chamber (114) to 116), at the rear structure of a vehicle provided with a rear cushion unit composed of,
When the rod (118) is provided with a through hole (136) consisting of a small diameter portion (133) , a step portion (134) and a large diameter portion (135 ) in the axial direction, the tip approaches the step portion (134). flow control for controlling the flow rate of the damper oil moving from the generates a throttling effect one chamber (114) to said other chamber (115) or vice said other chamber (115) said one chamber from (114) rods (137) inserted the the large diameter portion (135), the rear end side of the flow rate control rod (137), the brake oil pressure chamber to accumulate the brake fluid to push the rear end face of the flow control rod (137) (138) is provided, the first hydraulic line (76) is extended from the brake oil hydraulic chamber (138), and the tip of the first hydraulic line (76 ) is connected to the master cylinder (63). ,
A cylindrical member (171) is inserted into the large diameter portion (135), the hollow interior of the cylindrical member (171) constitutes the small diameter portion (133), and one end of the cylindrical member (171) is the stepped portion ( rear structure of a vehicle provided with a rear cushion unit, characterized in that it constitutes a 134). A joint member (78) for branching the brake oil supplied from the master cylinder (63 ) is interposed in the middle of the first hydraulic line (76) , and a second part is provided from the branch port of the joint member (78) . hydraulic line (82) is extended, this second hydraulic line (82) the rear cushion unit of a tip according to claim 1, wherein a coupled to the rear brake caliper (81) of Rear structure of the equipped vehicle. The rear member according to claim 2, wherein the joint member (78) is provided with a shut-off valve (185) capable of shutting off a flow of brake oil to the brake oil hydraulic chamber (138) . rear structure of a vehicle provided with a cushion unit. The said flow control rod (137) is provided with the urging member (162) which prevents that a front-end | tip approaches the said step part (134) , The claim 1, 2 or 3 characterized by the above-mentioned. rear structure of the rear cushion unit is provided vehicle. The urging member (162) is a return spring (163) , and the return spring (163) is provided on a flange portion (167) attached to the flow rate control rod (137 ) and the rod (118). rear structure of claim 1 rear cushion vehicle unit is provided in any one of claims 4, characterized in that it is interposed between the bundled receiving seat (165).

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