JPH0415593Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field The present invention is an anti-dive device for vehicles having a front fork consisting of telescopic fork legs, such as motorcycles and tricycles, especially for front wheels. A main passage that communicates between a lower hydraulic chamber and a reserve oil chamber in the telescopic fork legs that support the axle, a main valve that closes this main passage in conjunction with braking of the front wheels, and a main valve that opens at the bottom of the lower oil chamber. It consists of a bypass hole drilled in the fork leg, and a bypass valve having an orifice that communicates this bypass hole with the reserve oil chamber. When the front wheels are braked, the damping force generated by the bypass valve causes the fork leg to Relates to something that regulates contraction action.

(2) Prior Art Generally, in such an anti-dive device, the bypass hole that opens at the bottom of the lower hydraulic chamber in the fork leg is drilled from the lower end surface of the fork leg. remains, and conventionally the machined hole is closed with a screw plug.

(3) Problems to be solved by the invention However, since the support bolt for supporting the front wheel is screwed into the fork leg from the lower end,
According to the conventional structure, the support bolt and the screw plug must be arranged in parallel at the lower part of the fork leg, and therefore the lower end of the fork leg must be formed with a large diameter, and the bypass hole etc. There is a problem that the number of processing steps is large.

Therefore, an object of the present invention is to provide the anti-dive device that can contribute to slimming down the lower end of the fork leg, reducing the number of processing steps, and simplifying the structure.

B. Structure of the invention (1) Means for solving the problem In order to achieve the above object, the present invention provides a machined hole drilled in the lower end of the fork leg to form the bypass hole. It is characterized by a support bolt screwed into the lower end of the fork leg that is closed at the inner end to support the fork leg.

(2) Effects According to the above configuration, the bypass hole, its processed hole, and the support bolt are arranged on the coaxial plug, making it possible to slim down the lower end of the fork leg.

Furthermore, since the support bolt also serves as a screw plug for the machined hole, a screw plug is not required.

Furthermore, the machined hole and the bypass hole can be machined at once using the same drill when preparing the screw hole of the support bolt.

(3) Example An example in which the present invention is applied to a front wheel suspension system of a motorcycle will be described below with reference to drawings.
In Fig. 1, a front fork 1 of a motorcycle has a pair of telescopic fork legs 2 on the left and right.
(only one is shown in the figure), and the lower ends of both front forks 2 support both ends of a wheel 4 that rotatably supports a front wheel hub 3.

An annular brake disc 5 is integrally attached to one side of the hub 3, and a hydraulic brake caliper 6 is provided so as to straddle this brake disc 5 from the left and right sides. The brake caliper 6 is integrally supported by a bracket 7, which is rotatably supported by one of the fork legs 2 adjacent thereto via a pivot shaft 8. The hydraulic input port 6a of the brake caliper 6 has a hydraulic conduit 9 connected to a brake master cylinder (not shown).
is connected.

The fork leg 2 includes a bottom case 10 and a fork pipe 11 that is slidably fitted into the bottom case 10. An axle holder 12 is provided at the lower end of the bottom case 10 so as to sandwich the end of the axle 4. Each pair of support bolts 13, 13' and nuts 14, 1
4'.

The support bolts 13, 13' have threaded portions 13a at both ends.
13b, 13a', 13b', one threaded part 1
3a, 13a' are tightly screwed into screw holes 15, 15' drilled in the lower end surface of the bottom case 10, and the other threaded portions 13b, 13b' are screwed into nuts 14, 14' which penetrate the axle bottom 12. will be combined.

A seat pipe 20 is fixed concentrically inside the bottom case 10, and a piston 21 integrally formed at the upper end of the seat pipe 20 slides on the inner peripheral surface of the fork pipe 11. It's becoming like that. Inside fork pipe 11,
Suspension spring 22 between its upper end and piston 21
is contracted and biases the fork leg 2 in the direction of extension.

In addition, on the inner peripheral surface of the lower end of the fork pipe 11,
A buffer valve mechanism 23 having an orifice and a check valve is installed between the seat pipe 20 and the upper and lower hydraulic chambers 2 communicating through the buffer valve mechanism 23.
4 and 25 are formed around the sheet pipe 20.

A relay oil chamber 28 connected to a reserve oil chamber 27 inside the seat pipe 20 and the fork pipe 11 is defined by a partition wall 26 at the lowest part of the bottom case 10 . Furthermore, a check valve 29 is provided at the upper part of the partition wall 26 to allow oil to flow in only one direction from the relay oil chamber 28 to the lower hydraulic chamber 25.

An anti-dive device 30 is provided at the lower part of the bottom case 10 of the fork leg 2 adjacent to the brake caliper 6. This device 30 includes a housing 32 that has a main passage 31 that communicates between a lower hydraulic chamber 25 and a relay oil chamber 28 and is fixed to one side of a bottom case 10, and a housing 32 that has a main passage 31 that communicates between a lower hydraulic chamber 25 and a relay oil chamber 28 and is fixed to one side of a bottom case 10. A piston valve 33 as a main valve is slidably provided in the housing 32, and a return spring 3 is provided in the housing 32 and biases the piston valve 33 in the opening direction.
4, a bypass hole 35 that is bored in the bottom case 10 and opens at the bottom of the lower hydraulic chamber 25, and a bypass valve 36 that communicates between the bypass hole 35 and the relay oil chamber 28. ,
It is connected to the brake caliper 6 via a link 37 so that it is pressed in the valve closing direction by the braking torque received by the brake caliper 6 during braking of the front wheels.

The bypass hole 35 is connected to one of the screw holes 15
When machining the pilot hole, it is arranged coaxially with the screw hole 15 so that it can be machined with the same drill, and therefore the pilot hole is used as the machining hole 38 of the bypass hole 35. This processed hole 38 is closed by the inner end of the support bolt 13 screwed into the screw hole 15.

The bypass valve 36 is rotatably fitted into a valve hole 39 bored in the side wall of the bottom case 10 so as to be perpendicular to the bypass hole 35, and has an inner end facing the relay oil chamber 28 and an outer end. A knob 36a is attached. The bypass valve 36 also includes an axial bypass hole 40 that opens into the relay oil chamber 28, and a plurality of, for example, three, radial orifices 41 that can communicate between the bypass hole 40 and the bypass hole 35.
42 and 43 (see Figure 2) are drilled. These orifices 41, 42, 43 have different hole diameters, and are moved one by one to a position in communication with the bypass holes 35, 40 by adjusting the rotation of the knob 36a. That is, the bypass valve 36
has three adjustment positions.

A click stop device 44 is provided to hold the bypass valve 36 in these adjusted positions.
This device 44 includes three notches 45 ₁ , 45 ₂ , 45 ₃ recessed in the outer peripheral surface of the bypass valve 36 between each orifice 41 , 42 , 43 , and these notches 45 ₁ , 45 ₂ , 45 _{3 .} It is composed of a ball 46 that selectively engages with one of the notches, and a coil spring 47 that biases the ball 46 in the direction of engagement with the notch.
The ball 46 is accommodated in the machined hole 38, and the coil spring 47 also holds the ball 46 in the machined hole 38.
6 and support bolt 13.

Next, to explain the operation of this embodiment, when the brake caliper 6 is not in operation, the piston valve 36 of the anti-dive device 30 is in an open state, and when the fork leg 2 attempts to contract in this state,
Since the lower hydraulic chamber 25 is pressurized and the upper hydraulic chamber 24 is depressurized, the oil in the lower hydraulic chamber 25 flows through the check valve of the buffer valve mechanism 23 to the upper hydraulic chamber 24 with low flow resistance. , flows through the main passage 31 to the relay oil chamber 28 and further to the reserve oil chamber 27 with almost no resistance. As a result, a light damping force is generated in the buffer valve mechanism 23, and no damping force is generated in the anti-dive device 30.

On the contrary, when the fork leg 2 attempts to extend, the upper hydraulic chamber 24 is pressurized and the lower hydraulic chamber 25 is depressurized. The oil flows to the lower hydraulic chamber 25 with a large resistance, and at the same time, the oil in the reserve oil chamber 27 also flows to the lower hydraulic chamber 25 via the relay oil chamber 28 and the main passage 31. As a result, a large damping force is generated in the buffer valve mechanism 23, but in this case as well, no damping force is generated in the anti-dive device 30.

While the vehicle is running, when the brake caliper 6 is actuated by the output hydraulic pressure of a brake master cylinder (not shown) and braking force is applied to the brake disc 5 and therefore to the front wheels, a reaction force is applied from the brake disc 5 to the brake caliper. Due to the braking torque acting on the brake caliper 6, the brake caliper 6, together with the bracket 7, swings around the pivot 8 towards the piston valve 33, thereby pushing the piston valve 33 via the link 37, thereby causing the main The passage 31 is blocked.

Therefore, when compressive force is applied to the fork leg 2 due to an increase in the front wheel load due to braking, the lower hydraulic chamber 2
The oil of No. 5 is supplied to the bypass holes 35, 40 and the orifice 41 or 4 selected to communicate with these holes.
2 and 43 to the relay oil chamber 28 with a large flow path resistance, a large damping force corresponding to the flow path resistance of the orifice 41 or 42, 43 is generated, and this damping force causes the fork leg 2 to contract. Movement is moderately regulated.

In such an anti-dive device 30, the bypass hole 34 of the bottom case 10, its processed hole 38, and one support bolt 13 are arranged on the same axis, so that the lower end of the fork leg 2 can be made slimmer. can.

Further, since the support bolt 13 closes the machined hole 38, a dedicated screw plug is not required, resulting in a simplified structure.

Furthermore, the machined hole 38 and the bypass hole 35 can be machined all at once using the same drill when drilling the threaded hole 15 of the support bolt 13, resulting in a reduction in the number of processing steps.

Furthermore, since the machined hole 38 also serves as a holding hole for the ball 46 of the click stop device 44 and the coil spring 47, and the support bolt 13 also serves as a retainer for the coil spring 47, the structure is further simplified.

C. Effects of the invention As described above, according to the invention, the hole drilled in the lower end of the fork leg to form the bypass hole is screwed into the lower end of the fork leg to support the axle. Since the inner end of the support bolt was blocked, the bypass hole, its processed hole, and the support bolt were arranged coaxially, and the lower end of the fork leg was slimmed down.
As a result, the weight has been reduced, and the screw plug exclusively for the machined hole can be eliminated, simplifying the structure, and furthermore, it has become possible to simultaneously machine the bypass hole and the pilot hole of the support bolt screw hole. This can contribute to reducing the number of processing steps.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a vertical side view of the main parts of a front fork for a motorcycle equipped with an anti-dive device, and FIG. 2 is a sectional view taken along the line -- in FIG. 1. . 1...Front fork, 2...Fork legs,
3...Front wheel hub, 4...Axle, 5...Brake disc, 6...Brake caliper, 7...Bracket, 8...Pivot, 10...Bottom case, 1
1...Fork pipe, 12...Axle holder, 1
3... Support bolt, 14... Nut, 15... Screw hole, 24... Upper hydraulic chamber, 25... Lower hydraulic chamber, 27... Reserve oil chamber, 29... Check valve, 3
0...Anti-dive device, 31...Main passage, 32
... Housing, 33 ... Piston valve as main valve, 35 ... Bypass hole, 36 ... Bypass valve,
37... Link, 38... Machining hole, 39... Valve hole, 41, 42, 43... Orifice, 44...
Click stop device.

Claims (1)

[Scope of utility model registration request] A main passage communicating between a lower hydraulic chamber and a reserve oil chamber in a telescopic fork leg that supports the axle of the front wheel, a main valve that closes this main passage in conjunction with braking of the front wheel, and a bottom surface of the lower oil chamber. In a vehicle anti-dive device comprising a bypass hole drilled in a fork leg so as to be open and a bypass valve having an orifice communicating the bypass hole with the reserve oil chamber, in order to process the bypass hole. An anti-dive device for a vehicle, characterized in that a machined hole drilled in the lower end of the fork leg is closed with an inner end of a support bolt threaded onto the lower end of the fork leg to support the axle. .