JPH0348432Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an improvement in the solenoid structure of a front fork that controls the compression side damping force in response to an external signal.

(Prior art) In order to prevent the front wheel side of a motorcycle from sinking during braking, a relief valve is provided in the passage through which hydraulic oil flows when the front fork is operated on the pressure side, and this relief valve is closed during braking, for example. A front fork with an anti-nose dive function is known, which prevents the flow of hydraulic oil and suppresses contraction of the front fork (see, for example, Japanese Patent Application No. 107866/1986).

In addition to such an anti-nose dive function, the applicant has proposed a device as shown in Fig. 2 that allows movable control of the damping force of the front fork according to driving conditions using an external signal. .

To explain this based on the drawings, an inner tube 2 connected to the vehicle body side is slidably inserted into an outer tube 1 connected to the single wheel side. A cylinder 3 whose base end is connected to the outer tube 1 is in sliding contact with the inner periphery of the inner tube 2 .

Although not shown, a piston is provided at the tip of the inner tube 2, and a compression side oil chamber that contracts during compression operation is formed on the lower surface of the piston, and an extension side oil chamber that contracts during extension operation is formed on the upper surface of the piston. Ru. The pressure side oil chamber is always in communication with the internal passage 7 of the cylinder 3 via a port formed in the lower part of the cylinder 3.

This internal passage 7 communicates with an oil reservoir chamber 8 formed above the inner tube 2, and the gas sealed in the oil reservoir chamber 8 compensates for the inflow and outflow of hydraulic oil corresponding to the intrusion volume of the inner tube 2.

The upper end of the cylinder 3 has a piston portion (bearing portion) 9 which has an enlarged diameter and slides into contact with the inner circumference of the inner tube 2.
A solenoid 14 is coaxially connected to the upper part of the piston portion 9.

Further, a case 10 is connected to the upper part of the solenoid 14, and a communication passage 11 that communicates the internal passage 7 and the oil reservoir chamber 8 is formed inside the case 10.

Note that one end of a suspension spring 12 for supporting the vehicle body load is supported at the upper part of the case 10.

A perforated bracket 13 is integrally connected to the upper part of the cylinder 3, and a core 15 of a solenoid 14 is attached to the center of the bracket 13.

The solenoid 14 has a coil 1 on the outer periphery of the bobbin 16.
7 is wound around the core 15, and by energizing this coil 17, an attractive force is generated on the core 15.

A guide pipe 18 made of an insulating material is arranged on the inner periphery of the bobbin 16.
The core 15 is inserted and fixed inside the
A plunger 19 is slidably inserted into the guide pipe 18 facing the core 15.

The plunger 19 is made of magnetic material, and the core 15
It is attracted by the magnetization of.

A cylindrical spool guide 2 located on the outer periphery of the plunger 19 protruding outward from the bobbin 16
1 is provided, and this spool guide 21 is integrally formed as a part of the case 10, and is fitted and fixed from the upper surface of the bobbin 16.

Note that cutouts 21A and 23A are formed in the case 10 to allow hydraulic oil to pass therethrough.

A similar spool guide 23 is also integrally formed on the inner periphery of the distal end of the case 10.

A spool 25 is provided which is slidably supported by these spool guides 21 and 23.

A relief valve 24 is provided on the outer periphery of this spool 25, and the relief valve 24 is connected to the spring 25.
7 so as to contact the stepped portion of the spool 25.

Case 1 is located on the outer periphery of this relief valve 24.
A check valve 31 is provided on the inner periphery of the case 10, and this check valve 31 is urged by a lease spring 33 so as to come into contact with a stepped portion on the inner periphery of the case 10.

The outer periphery of the relief valve 24 and the inner periphery of the check valve 31 are designed to overlap, and when the spool 25 is displaced, the relief valve 24 contacts the check valve 31 to form valve seats that are seated on each other. As a result, the communication passage 11 formed between the inner circumference of the case 10 and the outer circumference of the spool 25 is closed.

The relief valve 24 and the check valve 31 are designed to perform a predetermined relief function and a check function, respectively, when the valves come into contact with each other and are closed, and when the valves are open, they merely constitute a passage.

In order to perform the function of the relief valve 24, that is, to close the valve, the spool 25 is displaced by the solenoid 14.

The spool 25 has a central body portion that is reduced in diameter relative to the large diameter portions at both ends, and the tip of the plunger 19 abuts against the inner stepped portion of the spool 25 .

The plunger 19 is urged by a return spring 38 so as to be separated from the core 15 when the solenoid 14 is not attracted.

On the other hand, a balance spring 39 is provided between the spool guide 23 and the spool guide 23 to bias the spool 25 against the return spring 38.

Therefore, when the solenoid 14 is energized and the plunger 19 is attracted to the core 15 while compressing the return spring 38, the spool 25 is displaced by the acting force of the spring 39 until it comes into contact with the spool guide 21, and in this state it is relieved. valve 24
The check valve 31 comes into contact with the check valve 31 and closes.

Incidentally, the spool guides 21 and 23 at both ends of the spool 25 and the relief valve 24 are formed to have the same diameter, and no axial force is generated by the hydraulic pressure acting on the spool 25.

Therefore, even if high pressure is applied from the lower surface of the relief valve 24 when the relief valve 24 is closed, the forces acting on the spool 25 in the axial direction cancel each other out, so the spool 25 is displaced by the hydraulic pressure. Never.

The energization of the solenoid 14 is controlled by a control circuit (not shown) when, for example, a brake operation is electrically detected during braking.

In the drawing, one half of the drawing shows the solenoid 14 in operation when it is energized, and the other half shows the non-operation state in which the solenoid 14 is not energized.

When the solenoid 14 is not energized, the spool 25 is simultaneously pushed back against the spring 39 by the force of the return spring 38 of the plunger 19, and the relief valve 24 is separated from the check valve 31 and opened. It is held in a valve state.

Therefore, the inner tube 2 is the suspension spring 12.
With the pressure-side operation that enters the inside of the outer tube 1 while compressing, the hydraulic oil in the pressure-side oil chamber passes through the inner circumference of the case 10 from the internal passage (7) 7 of the cylinder 3, and enters the valve open state from the notch 21A. relief valve 24
It flows into the oil reservoir chamber 8 through the other notch 23A.

Therefore, the hydraulic oil flows into the oil reservoir chamber 8 without resistance, and the inner tube 2 and outer tube 1 freely expand and contract in response to vibrations, maintaining a soft ride.

On the other hand, when the solenoid 14 is energized by a signal from the control circuit, the core 1
5 is magnetized, an attractive force acts on the plunger 19 and the plunger 19 is displaced against the return spring 38.

As the plunger 19 is displaced, the spool 25 is displaced following the spool 25 due to the acting force of the spring 39, and the relief valve 24 is closed.

Therefore, a low resistance is applied to the flow of hydraulic oil, and a high damping force is generated.

For example, when braking a vehicle, a compressive force is applied to the front fork depending on the degree of deceleration. For this reason, the hydraulic oil in the pressure side oil chamber 5 tries to flow out from the internal passage 7 of the cylinder 3 to the oil reservoir chamber 8, but since the relief valve 24 interposed in the communication passage 11 in the middle is closed, the hydraulic oil is not activated. Oil flow is blocked.

Therefore, the inner tube 2 cannot invade the outer tube 1, and the nose type of the front fork is prevented.

When the compression force of the pressure side oil chamber 5 exceeds the set load of the relief valve 24 (relief spring 27), the relief valve 24 opens and the front fork performs compression operation while maintaining the relief pressure.

When the vehicle is pushed up from the road surface while braking, etc.
When the compression pressure suddenly increases, by opening the relief valve 24 and releasing the hydraulic oil,
It absorbs and softens shock.

Solenoid 1 may be activated depending on operating conditions other than during braking.
By energizing 4, it is also possible to increase the damping force and improve the steering stability.

Note that when operating on the expansion side with the relief valve 24 closed, the hydraulic oil in the oil reservoir chamber 8 flows through the check valve 31.
Since it opens and flows into the internal passage 7 without resistance, insufficient suction will not occur during the expansion side operation.

(Problem to be solved by the invention) By the way, in this device, when the pressure side is operated, the hydraulic oil flows from the opening of the bracket 13 to the solenoid 1.
The coil 17 passes through the annular gap between the outer periphery of the inner tube 4 and the inner periphery of the inner tube 2 , and then passes through the inside of the case 10 . If the number of lines is increased, the outer circumference of the solenoid 14 will become larger, making it difficult to secure a sufficient passage area for passage of hydraulic oil.

If the aisle area cannot be secured in this way,
It becomes necessary to increase the inner diameter of the inner tube 2, which causes many problems as it leads to an increase in the diameter and weight of the front fork.

In order to solve these problems, the present invention makes it possible to omit the guide pipe arranged on the inner circumference of the bobbin by forming the bobbin with a strong member made of non-magnetic material, thereby reducing the diameter of the bobbin accordingly. The purpose is to ensure a sufficient passage area for pressure side hydraulic fluid.

(Means for Solving the Problems) Therefore, in the present invention, an inner tube is slidably inserted into an outer tube, the base end of a cylinder that is in sliding contact with the inner circumference of the inner tube is fixed to the outer tube, and the cylinder is inserted into the outer tube. A suspension spring is interposed between the cylinder and the inner tube, and a solenoid that is energized and excited by an external signal is provided at the top of the cylinder, and as the inner tube enters, the gap between the outer circumference of the solenoid and the inner circumference of the inner tube is removed from the cylinder internal passage. In the front fork, a relief valve is inserted in the middle of the communication passage from the internal passage to the oil sump chamber, and the relief valve is closed by the operation of the solenoid. was interposed between the suspension spring and the cylinder, the bobbin of the solenoid was made of an insulated non-magnetic strength member, and a core made of a magnetic material was integrally fitted to the inner periphery of the bobbin.

(Function) When the solenoid is not energized, the relief valve is open. Therefore, the front fork freely expands and contracts in response to vibrations, ensuring a soft ride.

On the other hand, when the solenoid is energized,
The relief valve closes. For this reason, the flow of hydraulic oil from the cylinder internal passage to the oil reservoir chamber is blocked, and the compression side damping force increases.

If the compression pressure becomes excessive, such as when the compressor is pushed up from the road surface during energization and excitation, the relief valve opens to release the pressure and absorb the impact.

Since the core of the solenoid is placed directly on the inner circumference of the bobbin, the overall diameter can be reduced and a sufficient passage area is secured between the outer circumference of the solenoid and the inner tube.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In FIG. 1, the bobbin 16 of the solenoid 14
A support pipe 16A made of an insulated non-magnetic material such as aluminum alloy, a pair of annular plates 16B and 16C made of synthetic resin or the like inserted into the support pipe 16A, and a support pipe 16A. A core 15 made of a magnetic material is screwed onto the inner periphery of the core 15.

A step is formed near the outer peripheral end of the support pipe 16A, and one annular plate 16B is inserted so as to come into contact with this step. . Further, an annular plate 16C is inserted into the opposite end, and these annular plates 16B and 16C
A coil 17 is wound between them.

Further, a threaded portion 15A is formed in a part of the core 15, and is screwed into a threaded portion 16D formed on the inner periphery of the support pipe 16A.

In this case, the head 15B of the core 15 is formed in the shape of a hexagonal bolt, and when the bracket 13 is fitted, one of the annular plates 16C and the bracket 13 are in contact with each other, and the core 15 is firmly attached to the support pipe 16A. Screw it into place.

At this time, the end surface of the support pipe 16A comes into contact with the bracket 13, so that the load of the suspension spring 12, which the case 10 receives, is transmitted from the support pipe 16A to the cylinder 3 via the bracket 13.

With this configuration, the bobbin 16 of the solenoid 14 is entirely made of non-magnetic material, and the coil 17
The core 15 on the inner circumference of the bobbin 16 is
is magnetized and attracts the plunger 19.

After the hydraulic oil passes through the opening of the bracket 13, it passes through the outer circumference of the solenoid 14 and the inner tube 2.
However, since the solenoid 14 does not require a conventional guide pipe on the inner periphery of the bobbin 16, its diameter can be reduced by that amount.
These annular gaps can be sufficiently secured to ensure smooth flow of the hydraulic oil sucked in, especially during the extension side operation.

Since the guide pipe is no longer necessary, the number of components of the solenoid 14 is reduced, and assembly becomes easier.

In this embodiment, the bobbin 16 is assembled, but the entire bobbin 16 may be formed integrally in advance.

Further, as the outer diameter of the solenoid 14 has been reduced, a cover may be attached to the outside of the bobbin 16 so that part of the load from the case 10 can be supported by this cover.

(Effects of the invention) As described above, according to the invention, the solenoid is interposed between the suspension spring and the cylinder, the bobbin of the solenoid is formed of an insulated non-magnetic strength member, and the inside of the bobbin is Since the core made of magnetic material is integrally fitted around the periphery, the core can be stored directly on the inner periphery of the solenoid, and therefore the outer periphery of the solenoid can be reduced by the amount without the guide pipe. This allows a sufficient flow area for hydraulic oil to be secured between the solenoid and the inner tube. Note that since the bobbin is made of a strong material, the load of the suspension spring can be received by the solenoid without any problem.

Furthermore, since the guide pipe can be omitted, the number of parts and assembly time are reduced, leading to cost reduction.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention;
FIG. 2 is a sectional view of a conventional example. 1...Outer tube, 2...Inner tube, 3...Cylinder, 7...Inner passage, 8...
Oil reservoir chamber, 9... Piston section, 10... Case, 1
1... Communication passage, 12... Suspension spring, 13... Bracket, 14... Solenoid, 15... Core,
16...Bobbin, 16A...Support pipe, 16
B, 16C... Annular plate, 19... Plunger, 2
4...Relief valve, 25...Spool.

Claims (1)

[Scope of utility model registration request] The inner tube is slidably inserted into the outer tube, the base end of a cylinder that slides on the inner periphery of the inner tube is fixed to the outer tube, and a suspension spring is interposed between the cylinder and the inner tube. A solenoid that is energized and excited by an external signal is installed at the top of the cylinder, and as the inner tube enters, hydraulic oil flows from the cylinder internal passage through the gap between the outer circumference of the solenoid and the inner circumference of the inner tube into the oil reservoir chamber above. , in the front fork in which a relief valve that closes when the solenoid is operated is interposed in the middle of the communication passage from the internal passage to the oil sump chamber, the solenoid is interposed between the suspension spring and the cylinder; A front fork solenoid structure characterized in that a bobbin is formed of an insulated non-magnetic strength member, and a core formed of a magnetic material is integrally fitted to the inner periphery of the bobbin.