JP2651578B2 - Variable spring constant device for stabilizer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a stabilizer spring variable device.

[Conventional technology]

As is well known, a stabilizer mechanism in a vehicle suspension system fixes both ends of a substantially U-shaped stabilizer to a lower arm via a link rod, and rotatably supports an intermediate portion thereof on the vehicle body side. When the left and right wheels of the vehicle move up and down in the same phase, the spring action by the stabilizer is not generated, but when the left and right wheels move up and down in opposite phases, the center of the stabilizer is fixed as a torsion bar. A spring force is applied, and a spring force of the stabilizer is applied so as to correct the phase difference when the left and right wheels move up and down in opposite phases, thereby increasing the rigidity of the vehicle against the rolls and improving the running stability of the vehicle. And However, when the roll stiffness is enhanced by the above-described stabilizer mechanism, the vibration on the spring of the vehicle is increased with an increase in the total spring constant of the suspension system, and the left and right wheels of the vehicle move up and down in opposite phases. When the vehicle travels on a undulating road surface, there is a fear that the ride comfort of the vehicle may be deteriorated.

Therefore, as one of means for preventing the above-described deterioration in ride comfort, the present applicant has previously developed a stabilizer spring constant variable device having a circuit configuration as shown in FIG.

That is, the movable cylinder 3 is provided between one end of a stabilizer provided to generate a torsional torque in accordance with the vertical movement difference between the left and right wheels of the vehicle and the lower arm, and constitutes the movable cylinder 3. The operation check valves 5a and 5b are provided in respective oil passages connecting the upper and lower chambers A and B defined by the piston body 12 in the cylinder body 9 to the accumulator 6 serving as a reservoir chamber.
A relief valve Vo is juxtaposed with an operation check valve 5b that allows communication between the accumulator 6 serving as a reservoir chamber and the lower chamber B, and the above-described cylinder remains in the cylinder body 9 except for a neutral position in a stroke range of the piston body 12 in the cylinder body 9. A bypass groove 15a, 15b is formed on the inner wall of the body 9.

Therefore, according to the apparatus of the applicant of the present invention, if the operation check valves 5a and 5b are released by the pilot operation, the movable cylinder 3 expands and contracts freely, that is, the torsional torque of the stabilizer is not transmitted to the lower arm. That is, when the vehicle travels on the undulating road surface, the vibration on the spring of the vehicle is prevented from being increased and the riding comfort of the vehicle is prevented from being deteriorated.

On the other hand, if the operating check valves 5a and 5b are so-called check valves that allow only one-way flow by releasing the pilot operation, the movable cylinder 3 will be in a locked state in which the expansion and contraction of the movable cylinder 3 will be stopped, and the torsional torque of the stabilizer will be transmitted to the lower arm. As a result, the roll of the vehicle when traveling on a flat road can be effectively stopped.

Even if the locked state of the movable cylinder 3 is caused, for example, when the piston body 12 is located on the lower chamber B side in the cylinder body 9, the locked state of the bypass groove 15 b formed on the inner wall of the cylinder body 9 is maintained. There is an inflow of oil from the upper chamber A and an inflow of insufficient oil from the accumulator 6 into the lower chamber B through the lower chamber B, and the piston body 12 is returned to the neutral position in the piston body stroke area. .

When the lock state is such that the piston body 12 is
, The oil flows from the lower chamber B into the upper chamber A through the bypass groove 15a formed in the inner wall of the cylinder body 9 and is actuated by the relief valve Vo. Thus, the piston body 12 returns to the neutral position in the piston body stroke area.

That is, when the movable cylinder 3 is locked, the movable cylinder 3 is at a standard level at a so-called neutral position so that an error with respect to the above level is not generated on the vehicle body side, and the vehicle is always kept at the same level at the time of locking, and It shall be stabilized.

[Problems to be solved by the invention]

However, in the above proposal, there is a disadvantage that the locked state of the movable cylinder 3 is caused without the piston body 12 being positioned at a completely neutral position in the piston body stroke area.

That is, when the piston body 12 is at a position other than the neutral position of the stroke area, even if a lock state is caused by the release of the pilot operation to the operation check valves 5a and 5b, the piston body 12 is in the lower chamber B side. The return to the vicinity of the neutral position by using the bypass groove 15b, and the operation check valve 5b due to the negative pressure on the lower chamber B side.
Oil can be easily returned to the neutral position even when the extension load is small due to the inflow of oil through
When the lock state occurs when the lock valve 12 is located on the upper chamber A side, after the return to the vicinity of the neutral position by using the bypass groove 15a described above, a complete pressure is applied as long as a large pressure load is applied and the relief valve Vo does not operate. Return to the neutral position cannot be expected, and the locked state is maintained at the incomplete neutral position.

As a result, in the stabilizer spring constant variable device shown in FIG. 5, when the movable cylinder 3 is locked, the upper end side may not be able to be maintained at a constant level, and the level difference between the left and right sides on the vehicle body side may be reduced. As a result, there is a disadvantage that the posture of the vehicle becomes unstable.

Therefore, the present invention firstly prevents the posture of the vehicle from becoming unstable when the movable cylinder is locked.
In addition, the two operation check valves are simultaneously or selectively operated by the solenoid valve, and the movable cylinder is promptly returned to the neutral position.
In addition, the switching operation of the movable cylinder can be performed more easily.
It is another object of the present invention to provide a stabilizer spring constant variable device which can switch the rigidity of the stabilizer to a plurality of stages.

[Means for solving the problem]

In order to solve the above-mentioned problems, the structure of the spring constant variable device of the stabilizer according to the present invention is changed by using a pair of springs disposed in a cylinder constituting a movable cylinder. Each of the oil passages communicating the upper and lower chambers with the reservoir chamber is provided with an operating check valve and a throttle, and each of the operating check valves is simultaneously or selectively opened and closed by a solenoid valve. The cylinder body, which is formed as described above, and is located at a neutral position of a piston body stroke area in the cylinder body, is provided with an oil hole of an oil passage communicating with a reservoir chamber. .

(Operation)

When the movable cylinder is in an extendable operating state,
When the torsional torque in the stabilizer is not transmitted to the lower arm side via a spring in the cylinder, the so-called stabilizer is in a soft state, and when the movable cylinder is in the locked state, the torsional torque in the stabilizer is transmitted to the lower arm side, and The rigidity against the roll becomes hard, and when one of the operating check valves is open, it becomes medium and the rigidity can be switched in three stages.

Further, even when the piston body in the cylinder body is at a position other than the neutral position when the movable cylinder is locked, oil flows out to the reservoir chamber through an oil hole formed in the cylinder body so as to correspond to the neutral position of the piston body stroke area. As a result, the piston body is returned to the completely neutral position, and when the piston body is returned to the completely neutral position, the oil hole is closed to the outer periphery of the piston body, thereby causing the movable cylinder to be completely locked. Will be done.

Even when the piston is at a position other than the neutral position in the cylinder when the movable cylinder is locked, the piston is urged by both springs to return to the neutral position promptly.

〔Example〕

 Hereinafter, the present invention will be described based on illustrated embodiments.

FIG. 1 shows an embodiment of the use of the spring constant variable device of the stabilizer according to the present invention, wherein the bent arm portions 1a, 1 of the stabilizer 1 formed in a substantially U-shape are shown.
One end of a is connected to a lower arm (not shown) via a link rod 2, and the movable cylinder 3 is arranged at a lower arm coupling portion at the other arm 1 a end.

However, two movable cylinders 3 may be provided between both ends of the arm portions 1a, 1a and the lower arm without using the link rod 2.

In this case, the rigidity of the stabilizer 1 is switched.

The stabilizer 1 is rotatably attached to a vehicle body (not shown) via vehicle body-side supports 4, 4 provided in the intermediate portion 1b.

The movable cylinder 3 is connected to the upper chamber A and the lower chamber B by an oil passage.
L1 and L2, the operation check valves 5a and 5b, and the throttles 0a and 0b can communicate with each other, and the accumulator 6 as a reservoir chamber communicates the upper and lower chambers A and B, respectively.

The inside of the movable cylinder 3 is connected to the accumulator 6 through another oil passage L3.

In FIG. 1, 7a indicates a right wheel, and 7b indicates a left wheel.

The movable cylinder 3 itself will be described a little.
As shown in FIG. 2, the mounting portion 8 on the lower arm side
A piston body 12 slidably connected to a piston body rod body 11 having a mounting portion 10 for attaching the stabilizer 1 to the cylinder body 9 having the piston body.
The interior of the cylinder 9 is divided into an upper chamber A and a lower chamber B by 12.

Small holes 13a, 13b are formed in the inner wall near both ends of the cylinder body 9, and oil passages L1, L2 are connected to the small holes 13a, 13b, respectively.

The opening position of the small holes 13a and 13b is determined by the inner wall of the cylinder body 9 where the outer periphery of the piston body 12 comes into sliding contact immediately before the piston body 12 reaches the extended position and immediately before the piston body 12 reaches the bottomed position. The outer periphery of the piston body 12 is a position where the small holes 13a and 13b are to be closed.

When the piston body 12 closes the small holes 13a and 13b, a so-called oil lock state is caused, and the extension and bottoming are prevented.

Further, an oil hole 15 is provided on the inner wall of the cylinder body 9 and at a neutral position 14 of the effective stroke area of the piston body 12.
Is provided.

The oil hole 15 is provided in the upper chamber A in the cylinder body 9.
The piston body on either side of the lower chamber B side
When there is 12, the connection of the oil passage L3 that allows communication between the inside of the cylinder body 9 and the accumulator 6 as the reservoir chamber is enabled.

The operation check valves 5a and 5b are connected to the oil passage L1,
In the oil passages L1 and L2, throttles 0a and 0b as throttle passages included in the operation check valves 5a and 5b are arranged, respectively.

Further, a pair of springs 16a and 16b are provided in the cylinder body 9, and the pair of springs 16a and 16b are provided.
6a and 16b urge the piston body 12 from both directions.

The balance by the pair of springs 16a and 16b is formed so as to be achieved when the piston body 12 is at the center position 14.

Therefore, when the operating check valves 5a and 5b are simultaneously opened and the upper and lower chambers A and B are in communication with each other, the cylinder 9 or the piston rod
The piston body 12 contracts one of the springs 16a or 16b by the action of the load applied to 11, and allows the movable cylinder 3 to expand and contract. At this time, the rigidity of the stabilizer 1 becomes soft.

At this time, it is assumed that the operated check valves 5a and 5b include the throttles 0a and 0b, which are throttle passages, so that the respective operating check valves 5a and 5b suddenly move to release the lock of the movable cylinder 3. Even if it is opened, the throttle effect by the throttle passage is caused, and the movable cylinder 3 does not suddenly expand and contract, so that a preferable expansion and contraction operation state is exhibited.

Each of the operated check valves 5a and 5b is opened by a push operation of a solenoid valve to be described later, which allows a so-called bidirectional flow.However, when the push operation is released by demagnetization of the solenoid valve, thereafter, The so-called operating check valves 5a and 5b are closing valves, and flow in one direction in the oil passages L1 and L2, that is, the upper and lower chambers from the accumulator 6 side which is a reservoir chamber.
Only the flow to the A and B sides is allowed, and at this time, the rigidity of the stabilizer 1 becomes hard.

The operation check valves 5a and 5b can be selectively opened and closed, and at this time, the rigidity of the stabilizer 1 is medium.

In short, the stiffness of the stabilizer 1 can be switched between three levels: soft, hard, and medium.

In the case where two movable cylinders 3 are provided on both sides of the stabilizer 1, the rigidity can be switched in more stages.

In the present embodiment, the cylinder body 9 includes:
Stopper 17 that effectively prevents so-called stretching and bottoming
a and 17b are arranged on the upper end side of the piston body 12 and on the inner bottom side of the cylinder body 9, respectively.

However, the positions of the stoppers 17a and 17b are not limited to those illustrated.

According to this embodiment having such a configuration, when the operation check valves 5a and 5b are in the open state, the movable cylinder 3 has the upper and lower chambers A and B in communication with each other, and the effective stroke of the piston body 12 is Is in a so-called free state in which the movement is not restricted within the range.

Therefore, the cylinder body 9 mounted on the wheel side moves up and down in accordance with the up and down movement of the left wheel 7b of the running vehicle, and the stabilizer 1 rotates in conjunction with the up and down movement of the other right wheel 7a. The piston body 12 on the arm 1a mounting side moves up and down.

Therefore, in the open state of the operation check valves 5a and 5b, the stabilizer 1 is in a so-called stabilizer-free state in which the distal end side of the arm 1a communicates with the right wheel 7a on the restraining side and the tip side of the arm 1a turns.

Under the condition that the piston body 12 can perform the free operation, the insufficient hydraulic oil in the movable cylinder 3 is replenished from the accumulator 6 serving as a reservoir, and conversely, the excess hydraulic oil in the movable cylinder 3 is removed from the accumulator 6. Is absorbed by

On the other hand, if the operation check valves 5a and 5b are so-called open valves, the upper and lower chambers A and B in the movable cylinder 3 are isolated from each other, so that the movement of the hydraulic oil between these two chambers A and B is interrupted. As a result, both the extension side and compression side movements of the piston body 12 are locked.

Therefore, the stabilizer 1 and the left and right wheel sides are in a rigidly connected state, and a so-called stabilizer action state in which a torsional torque is generated in the stabilizer 1 by the up and down movement of the right wheel 7a and the left wheel 7b in opposite phases. .

When each of the above-described operation check valves 5a and 5b functions simply as a closing valve by releasing the pilot operation, the subsequent movement of the piston body 12 in the cylinder body 9 is caused by the central position 14 of the cylinder body 9 concerned. Is controlled by the oil hole 15 provided in the inner wall of the.

That is, for example, when the piston body 12 is on the lower chamber B side, the hydraulic oil on the upper chamber A side is discharged with the retreat of the piston body rod body 11 from the inside of the cylinder body 9 also receiving the repulsive force of the spring 16b. The oil is supplied to the lower chamber B through the oil hole 15 and the operation check valve 5b, and the insufficient hydraulic oil in the lower chamber B is supplied from the accumulator 6 to the operation check valve 5b.
When the piston body 12 reaches the neutral position 14 of the piston body stroke area,
The outer periphery of the piston body 12 closes the oil hole 15, an oil lock state is caused in the upper chamber A, and the further movement of the piston body 12 is prevented.
Into a locked state in which expansion and contraction of the cable is prevented.

Also, even when the piston body 12 is in the upper chamber A side, the operation check valve 5a is provided in the upper chamber A, which becomes a negative pressure due to the movement of the piston body 12 also receiving the repulsive force of the spring 16a.
The hydraulic oil in the lower chamber B is replenished through the oil hole 15, and the hydraulic oil in the lower chamber B is absorbed into the accumulator 6 through the oil hole 15, so that the piston body 12 When the neutral position 14 is reached, the outer periphery of the piston body 12 closes the oil hole 15, and an oil lock state is induced in the lower chamber B, and the piston body 12 is closed.
Further movement of the movable cylinder 3 is prevented, and the movable cylinder 3 is locked.

When the movable cylinder 3 is locked at the completely neutral position as described above, the arm 1a of the stabilizer 1 and the lower arm are connected in a so-called rigid state.

Further, according to the present embodiment, when each of the operation check valves 5a and 5b is opened to release the locked state of the movable cylinder 3, even if the opening operation is suddenly caused, Since the operation check valves 5a and 5b include the throttles 0a and 0b, which are throttle passages, the outflow of hydraulic oil from the movable cylinder 3 and the inflow of hydraulic oil into the movable cylinder 3 are limited. And the movable cylinder 3
Will not be caused.

According to the present embodiment, it is possible to prevent the movable cylinder 3 from being extended and bottomed out by inviting the oil lock state at both ends in the cylinder body 9 and disposing the stoppers 17a and 17b. It is.

Therefore, according to the movable cylinder 3, if the rigidity of the roll stiffness of the stabilizer 1 is selected and the so-called stabilizer hard is selected, it is possible to cope with the rolling phenomenon and the pitching phenomenon in the traveling vehicle and improve the driving stability of the vehicle. If so-called stabilizer software is used, it becomes possible to maintain the damping force software in the running vehicle, and the riding comfort of the vehicle can be improved.

FIGS. 3 and 4 show a specific embodiment of the movable cylinder 3 described above.
As shown in FIG. 3, is formed integrally with an appropriate check valve 5a, 5b and accumulator 6 in an appropriate housing H.

The housing H has oil passages L1 and L2 that communicate the movable cylinder 3 and the accumulator 6, and an oil passage L3 (not shown) that allows communication between the inside of the movable cylinder 3 and the accumulator 6. ).

At the lower end of the housing H, there is provided a mounting portion H1 to a lower arm such as a ball joint.

At the upper end of the piston rod 11 described later, there is provided a mounting portion H2 for the stabilizer 1 formed of a ball joint or the like.

The cylinder body 20 constituting the movable cylinder 3 is formed in a part of the housing H so as to have a cylindrical shape with a bottom.
Are slidably housed and the piston body 12
Defines two oil chambers 23 and 24 as upper and lower chambers in the cylinder body 20.

The piston rod body 11 in which the piston body 12 is connected to the base end thereof using a piston body nut 21a has its tip projected outside the upper end side of the cylinder body 20.

The upper end side of the cylinder body 20 is closed by the attachment of the cap member 20a, and the piston rod body 11 penetrates the axis of the cap member 20a.

A seal 20b is provided on the outer peripheral side of the cap member 20a.
A bearing whose inner peripheral surface is in sliding contact with the outer peripheral surface of the piston rod body 11 is provided on the inner peripheral side of the cap member 20a.
20c is provided.

A stopper 17a is provided on the upper end surface of the piston body 12, and serves as a stroke restricting means when the piston body 12 rises a large stroke into the cylinder body 20.

Further, a pair of springs 16a, 16b for positioning the piston body 12 at a neutral position in the stroke area of the cylinder body 20 is housed in the cylinder body 20, and the springs 16a, 16b are provided. 16b urges the piston body 12 from both directions.

The oil passage L1 bored in the housing H is positioned so that when the piston body 12 extends and slides to a position immediately before the cylinder body 20, the opening is closed by the outer periphery of the piston body 12. The oil passage L2 is formed so that when the piston body 12 slides to a position immediately before the bottom in the cylinder body 20, the opening is closed by the outer periphery of the piston body 12. It is positioned and drilled.

The oil passage L3 is provided so that the piston body 12 is
When the piston body 12 is in the neutral position,
Is positioned so as to be closed at the outer periphery of.

Note that a piston ring biased by a backup ring is interposed on the outer periphery of the piston body 12, and the piston ring closes each opening of the oil passages L1, L2 and L3.

Operate check valves 5a and 5b are provided in the oil passages L1 and L2, respectively. As shown in FIG. 4, each of the operate check valves 5a and 5b is formed in the same manner as a so-called poppet valve. Have been.

Hereinafter, one of the operation check valves 5a will be described.

That is, the poppet 31 is housed in the valve seat member 30 disposed in the housing H so as to be movable up and down, and when the poppet 31 is raised, the poppet 31 is located upstream and downstream of the poppet 31. Communication, and conversely,
When the poppet 31 is lowered, the communication is allowed.

In order to fix the valve seat member 30 in the housing H, the poppet 31 is provided with an upper end of a spring 33 whose lower end is respectively locked on an upper surface of a cap member 32 screwed to the housing H. It is touched and urged in the upward direction.

Further, an annular groove is formed in the outer peripheral side surface of each of the valve seat members 30, and an oil hole 30a is formed in the thickness thereof to allow communication between the outer peripheral side and the inner peripheral side of each of the valve seat members 30. And the annular grooves communicate with the oil passages L1 and L2, respectively.

Each of the poppets 31 has a push rod at the tip
The distal end of the push rod 34 is adjacent to the push rod 34, and a solenoid valve V is disposed at the rear end of the push rod 34.

The solenoid valve V includes a coil 35,
It comprises a movable iron core 36, a drive rod 37 and a cushion member 38. When excited, the drive rod 37 extends to push the push rod 34 to the left in the figure, and when demagnetized, it retreats via the spring 32 and the poppet 31.

Therefore, in the present embodiment, the respective operation check valves 5a and 5b are opened by the push action of the solenoid valve V, whereby the poppet 31 is retracted by the push rod 34 that advances, and the spring is activated by the demagnetization of the solenoid valve V. When the push rod 34 moves backward, the poppet 31 advances, and functions as a closing valve that makes the oil passages L1 and L2 flow paths in one direction.

When each of the operation check valves 5a and 5b is opened, the movable cylinder 3 is allowed to expand and contract, and when each of the operation check valves 5a and 5b functions as a closing valve, the expansion and contraction is prevented.

An accumulator 6 is provided in the housing H. The accumulator 6 defines an oil chamber 40 and an air chamber 41 in the housing H as shown in FIG. , A rubber film 42
The outer edge of 42 is fixed by a cap member 43 screwed into the housing H so as to isolate the air chamber 41 from the outside.

The oil chamber 40 is provided with each of the operating check valves.
It is formed so as to communicate with the oil passages L1 and L2 via 5a and 5b, and is also communicated with the oil passage L3.

The air chamber 41 communicates with the outside through an opening formed in the cap member 43 in the present embodiment, and is set so that the inside of the air chamber 41 has a so-called atmospheric pressure. ing.

〔The invention's effect〕

 As described above, the present invention has the following effects.

The upper and lower chambers in the movable cylinder communicate with each other via an oil passage and with the reservoir, and each of the oil passages is provided with an operation check valve, so that the stabilizer can be operated only by opening and closing the operation check valve. Can be varied, and the vehicle attitude can be adjusted according to the traveling road surface condition of the vehicle.

At this time, when the operation check valve is simultaneously opened, it becomes soft, when it is closed at the same time, it becomes hard, and when either one is opened, it becomes medium.

The open / close operation of the operation check valve is performed by using a solenoid valve, so that the remote control can be performed and the operation can be easily performed. Therefore, the structure is simple, the installation space is not restricted, and the assembling property is simplified.

With one pilot operation, the two operation check valves are simultaneously opened, and when the operation check valve is opened, the hydraulic oil passes through the throttle, so that a predetermined damping action is enabled and the sudden expansion and contraction of the movable cylinder is prevented in advance. In addition, the ride comfort of the vehicle is not deteriorated.

When the locked state of the movable cylinder is caused, the locked state of the movable cylinder is promptly induced at the complete neutral position, and the posture of the vehicle can be quickly stabilized.

Since the whole apparatus can be so-called compact, it is advantageous to equip a vehicle with a multi-hour operation.

Since the use of the relief valve is eliminated, there is an advantage that cost reduction can be expected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram showing a device for varying the spring constant of the stabilizer according to the present invention, and FIG. 3 is a specific example of the device for varying the spring constant of the stabilizer according to the present invention. FIG. 4 is a partial longitudinal sectional view of FIG. 3, and FIG. 5 is a circuit diagram showing a conventional example. 1 Stabilizer, 3 Movable cylinder 5a, 5b Operate check valve 6 Accumulator as reservoir chamber 7a Right wheel, 7b Left wheel 9,20 Cylinder, 12 Piston 14 ... Neutral position, 15 ... Oil holes 16a, 16b ... Spring, 23, A ... Upper chamber 24, B ... Lower chamber, 31 ... Poppet 34 ... Push rod, L1, L2, L3 ... Oil passages 0a, 0b: throttle, V: solenoid valve

Claims (2)

(57) [Claims] 1. A stabilizer spring comprising a movable cylinder disposed between at least one end of a stabilizer disposed to generate a torsional torque in accordance with a vertical movement difference between left and right wheels of a vehicle and a lower arm. In the constant variable device, a piston body is slidably inserted into a cylinder body constituting a movable cylinder, and the piston body is urged from both directions by a pair of springs arranged in the cylinder body, and defines upper and lower chambers in the cylinder body. An operating check valve and a throttle are provided in each of the oil passages communicating the upper and lower chambers with the reservoir chamber, and each of the operating check valves is formed so as to be opened or closed simultaneously or selectively by a solenoid valve. And the cylinder body, which is in the neutral position of the piston body stroke area in the cylinder body, communicates with the reservoir chamber. Stabilizer spring constant variable and wherein the oil hole of the oil passage is formed. 2. The operating check valve according to claim 1, wherein the operating valve has a poppet opposed to the push rod, and the push rod moves forward and retracts the poppet when the solenoid valve is excited. The variable spring constant device of the stabilizer as described in the above.