JPS6233675Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an anti-nose dive device that prevents sinking during control by controlling the damping force of a shock absorber in accordance with the braking force. This invention relates to an anti-nose dive mechanism that can change its characteristics, such as changing the setting of the start of anti-nose dive action, in accordance with the adjustment of brake touch by adjusting a return spring.

A shock absorber is attached to the front fork of a two-wheeled vehicle, for example, to control the movement of a suspension spring, and by quickly damping vibrations, it cushions shocks on rough roads and improves tire grounding. Yes, it is one of the important parts in vehicles. In this case, when a two-wheeled vehicle is braked while the vehicle is running, a force based on the moment of inertia corresponding to the angle of inclination is applied to the front fork, compressing it, resulting in a sinking phenomenon (nose dive phenomenon).
occurs.

In response to this, the applicant of the present application has previously proposed an anti-nose dive device that prevents the sinking phenomenon by controlling the damping force of a shock absorber in accordance with the braking force. This anti-nose dive device provides resistance to the hydraulic fluid and suppresses sinking by installing a relief valve in the hydraulic fluid passage of the shock absorber that changes the set pressure in response to the braking force. .

FIG. 1 is a cutaway sectional view of essential parts showing an example of an anti-nose dive device that controls the damping force of the above-mentioned shock absorber in accordance with the braking force. A push rod 2 is supported by a bearing 3 so as to be slidable in the axial direction. A cylinder chamber 4 to which brake hydraulic fluid is supplied is provided at one end of the valve housing 1.
The end face of the push rod 2 is pressed by a piston rod 6 extending from a piston 5 housed in the cylinder chamber 4. A head 7 with an enlarged diameter is formed at the other end of the push rod 2, and a small diameter tapered surface 8 is formed around the head 7, and a groove 9 for receiving a spring is formed in the end surface. ing. On the other hand, on the inner wall of the valve housing 1 facing the end surface of the head 7 formed on the push rod 2, a spring receiver 10 is provided which protrudes coaxially with respect to the push rod 2.
and a groove 9 provided on the end face of the push rod 2.
A return spring 11 is interposed between the two. Further, inside the valve housing 1, a hollow disk-shaped leaf valve body 12 inscribed in the cylindrical portion is provided so as to be movable in the axial direction. Relief spring 13 interposed between the inner wall
Snap spring 1 as a position regulating member
It is pushed to 4. In this case, the central hole 12a of the leaf valve body 12 is connected to the head 7 of the push rod 2.
The small diameter tapered surface 8 of the head 7 fits into the central hole 12a, thereby opening the ports 15, 16.
Restricts the flow of hydraulic oil between. Therefore, this small diameter tapered surface 8 and the leaf valve body 12 constitute a relief valve 17. By connecting the ports 15 and 16 to a pipe that communicates the oil chamber of the shock absorber and the oil reservoir chamber, this relief valve 17 allows hydraulic oil to be discharged from the oil chamber that contracts when the pressure side is operated to the oil reservoir chamber. control the flow of

In the anti-nose dive device configured as described above, during normal driving, the brake is not operated, so the hydraulic pressure of the brake hydraulic oil in the cylinder chamber 4 is low, and the push rod 2 is moved by the return spring 11. and has been pushed back to the state shown. For this reason, the small-diameter tapered surface 8 of the head 7 provided at the tip of the push rod 2 is not joined to the leaf valve body 12, but maintains a predetermined gap. Therefore, in this state, the relief valve 17 is fully open, and the ports 15, 1
It provides almost no resistance to the pressure side hydraulic oil of the shock absorber flowing between the cylinders and the cylinder.

Next, when the brake is operated, hydraulic oil for the brake system is supplied to the cylinder chamber 4, so the oil pressure in the cylinder chamber 4 increases in accordance with the braking force. When the internal pressure rises, the piston 5 housed in the cylinder chamber 4 is pushed out, and the piston rod 6 is moved toward the return spring 11.
The push rod 2 is moved in the direction of the leaf valve body 12 against the force. As a result, the small-diameter tapered surface 8 of the head 7 provided at the tip of the push rod 2 will fit into the leaf valve body 12, and the central hole 12a of the leaf valve body 12 will be constricted and the pressure side actuated. Restrict oil flow. When the pressure of this pressure side hydraulic oil rises above the pressing force of the relief spring 13, the leaf valve body 12 moves away from the small diameter tapered surface 8 of the head 7, and the relief valve 17 is opened. . Therefore, in this state, as long as the set pressure of the relief valve determined by the relief spring 13 is not exceeded,
The flow of the hydraulic fluid on the pressure side of the shock absorber is significantly restricted, making it difficult to compress the fluid, thereby preventing sudden sinking during braking.
The set pressure of the relief valve 17 increases depending on the insertion amount of the small diameter tapered surface 8 of the push rod 2. In other words, the push rod 2 is pushed out to a position where the repulsive force of the return spring 11 is balanced against the pressing force of the piston 5 corresponding to the braking force. As a result, the fitting length of the small-diameter tapered surface 8 at the tip of the push rod 2 into the inner meridian hole 12a of the leaf valve body 12 is made variable by the brake pressure. Therefore, the relief setting pressure of the relief valve 17 increases in response to the amount of movement of the push rod 2, that is, the braking force (braking force), and as a result, the depression increases in proportion to the braking deceleration. The phenomenon is prevented.

In recent years, in vehicles such as high-speed on-road vehicles (two-wheeled vehicles that normally travel on road surfaces), where the braking effect and anti-nose dive characteristics have a sensitive effect on steering stability, changes in passenger weight and cargo load, wear of brake pads, etc. There is a strong desire to be able to easily adjust the anti-nose dive action and change the characteristics to suit the braking action in response to various conditions.

However, although the anti-nose dive mechanism with the above configuration can reliably prevent the sinking phenomenon in response to the braking force, the anti-nose dive characteristic that responds to the braking action depends on predetermined design conditions. It becomes fixed. Therefore, the present invention has a spring pressure adjustment mechanism that adjusts the return spring of the push rod that moves in response to the brake operating force, and has an anti-nose dive characteristic (sinking prevention characteristic) that can easily be adjusted from the outside to accommodate changes in the brake braking operation. To provide an anti-nose dive device that allows adjustment changes.

Hereinafter, the anti-nose dive device according to the present invention will be described in detail with reference to the drawings.

2 and 3 are a cutaway sectional view and a right side view of essential parts showing an embodiment of the anti-nose dive device according to the present invention, and the same parts as in FIG. 1 are designated by the same symbols. In the figure, reference numeral 18 denotes a pressure regulating bolt having a flange 19 at the end and a through hole 20 in the center. After being inserted into a through hole 21 formed in the section with the flange 19 facing inside, it is tightened and fixed in an airtight state with a tote 23 via a washer 22. The inner end surface of the pressure regulating bolt 18 has three grooves 2 in the radial direction, as shown in FIG.
4, 25, and 26 are equally distributed. These three grooves 24, 25, 26 are
As shown in the side view facing each groove 24, 25, 26, the depths D ₁ , D ₂ , D ₃ of the grooves are 2 mm and 1.5 mm.
mm, 1mm. On the other hand, pressure adjustment bolt 1
A pressure regulating shaft 27 is inserted into the through hole 20 formed at 8 while being sealed by an O-ring 28, and grooves 24 to 2 are formed at the inner end thereof.
A pin 29 having a diameter smaller than 6 is fixedly passed through in the lateral direction. Also, the pin 29 of this pressure regulating shaft 27
There is a return spring 1 at the tip of the section.
A spring guide 30 for receiving 1 is fixed. Note that the relief spring 13 is supported by a flange 19 of the pressure regulating bolt 18.

In the anti-nose dive device configured as described above, since the return spring 11 is engaged with the spring guide 30 fixed to the inner end of the pressure regulating shaft 27, the push rod 2 and the pressure regulating shaft 27 are pressed in a direction that separates them from each other. Therefore, since braking pressure is not supplied to the cylinder chamber 4 during normal running, the push rod 2 is not supplied with the return spring 1.
1, the relief valve 17 is in an open state and provides almost no resistance to the pressure side hydraulic fluid of the shock absorber, as in the conventional case.

Next, when the tip of a screwdriver is inserted into the slit 31 provided on the outer end face of the pressure regulating shaft 27 and rotated, a pin 29 is formed on the end face of the pressure regulating bolt 18 every time it rotates 60 degrees. The grooves 24, 25, and 26 shown in FIG. In this case, since the grooves 24, 25, and 26 are formed with depths of 2 mm, 1.5 mm, and 1 mm as described above, if the 2 mm of the groove 24 is used as a reference, every 60 degrees of rotation to the right is 0.5 mm. The pressure regulating shaft 27 is pushed inward by mm. As a result, the spring guide 30 provided at the inner end of the pressure regulating shaft 27 moves toward the push rod 2 by 0.5 mm, and as a result, the return spring 1
1 is compressed. Therefore, this pressure regulating shaft 27
By rotating the return spring 11, the compression force of the return spring 11 can be changed to three levels every 60 degrees of rotation.

When the amount of compression of the return spring is varied,
As the amount of compression increases, the repulsive force increases, so unless the pressure of the hydraulic oil applied to the cylinder chamber 4 changes accordingly, the amount of movement of the push rod 2 relative to this will change. In other words, since the amount of movement of the push rod 2 to the leaf valve body 12 required to exert the anti-nose dive effect changes, the timing at which the anti-nose dive starts to take effect can be changed. Characteristics can be changed.

In other words, when the setting conditions of the brake system are constant, that is, there is no change in brake touch or wear on the pads, the position where the groove 24 and pin 29 engage is the base position, and the pressure regulating shaft 27 is moved from this position. of
The relief setting pressure does not change each time it is rotated by 60 degrees because the initial setting of the relief spring 13 is not changed, but the timing at which the anti-nose dive starts to take effect can be varied in three stages by changing the operating state of the push rod 2 in response to the brake operating force. will be done. Since the anti-nose dive characteristic corresponding to this brake actuation force can be changed by simply rotating the pressure regulating shaft 27 protruding outward, the pressure regulating operation is also extremely easy. For example, as shown in FIG.
8 is marked with a symbol, corresponding to the position of the grooves 24, 25, 26, and the slit 3 provided on the outer end surface of the pressure regulating shaft 27 is
If the direction of 1 matches the direction of pin 29,
By simply matching the direction of the slit 31 with the symbols, it is possible to easily change the characteristics so that the anti-nose dive characteristics can be exhibited under a gradually weaker brake touch as the number of the symbols increases. In this case, the grooves 24 to 26 are semicircular,
Further, since the pin 29 is circular, the pressure regulating shaft 27 can be easily rotated.

Furthermore, in the present invention, if there is a change in brake touch or pad wear, correction adjustment can be made so that the set anti-nose dive characteristics do not change. In other words, when the pressure applied to the cylinder chamber 4 increases or decreases due to a change in the brake system, the pressure can be adjusted to increase or decrease the repulsive force of the return spring 11 commensurate with the increase or decrease in pressure. It can be adjusted and maintained without compromising braking action and anti-nose dive characteristics.

Further, in the above embodiment, the pressure regulating bolt 18 is provided separately from the valve housing 1, but it may be integrated with the valve housing 1 if the groove can be machined from the inside.

As explained above, the present invention has a spring pressure regulating mechanism that externally regulates the pressure of the return spring of the push rod that responds to the brake operating force, which not only makes it possible to easily vary the anti-nose dive characteristics. , brake operation adjustment while maintaining anti-nose dive characteristics,
Changes can be made and have advantageous effects in practice.

[Brief explanation of the drawing]

FIG. 1 is a cutaway sectional view of a main part showing an example of a conventional anti-nose dive device, FIGS. 2 and 3 are a cutaway sectional view and an end view of a main part showing an example of an anti-nose dive device according to the present invention, FIG. 4 is an end view of the pressure regulating bolt shown in FIG. 2, and FIG. 5 is a side view showing grooves formed in the pressure regulating bolts a, b, and c. 1... Valve housing, 2... Push rod, 4... Cylinder chamber, 5... Piston, 6...
Piston rod, 7...head, 8...tapered surface,
9...Groove, 11...Return spring, 12...
...Leaf valve body, 12a...Central hole, 13...Relief spring, 15, 16...Port, 17...
...Relief valve, 18...Pressure adjustment bolt, 19...
... Flange portion, 20, 21 ... Through hole, 23 ... Nut, 24, 25, 26 ... Groove, 27 ... Pressure adjustment shaft, 29 ... Pin, 30 ... Spring guide, 31 ... Groove.

Claims (1)

[Scope of utility model registration request] An anti-nose dive device has a relief valve interposed between ports through which hydraulic oil discharged when the shock absorber operates on the pressure side, and increases the set pressure of this relief valve in accordance with the brake operating force. The push rod is biased by a return spring to respond to the brake actuation force and counteract this brake operating force, and the leaf valve body position regulating member located near the tip of the push rod is biased by the relief spring to press. In addition, the relief valve is constituted by a leaf valve body provided to be able to move backward against the relief spring at the time of relief, and a spring pressure regulating mechanism is provided for regulating the return spring setting pressure of the push rod from the outside. Anti-nose dive device.