JP3291779B2 - Variable flow area mechanism and damping force switching mechanism for shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention expands the displacement of a laminated piezoelectric body using a displacement magnifying mechanism,
A channel area variable mechanism for changing the channel area of the fluid passage; and
The present invention relates to a damping force switching mechanism of a shock absorber that switches a damping force by changing a flow passage area of an oil passage .

[0002]

2. Description of the Related Art Conventionally, for example, it is mounted on a vehicle or the like,
As a damping force switching mechanism of a shock absorber capable of switching a damping force according to a running state or a change in posture of a vehicle, an upper and lower section divided by a piston slidably fitted to a cylinder.
There is known an oil passage that switches a damping force by changing a flow passage area of an oil passage by moving a damping force switching valve interposed in an oil passage that connects two oil chambers.

As a mechanism for moving the damping force switching valve, a mechanism using a piezoelectric body such as a piezo element as an actuator is known. A piezoelectric body is suitable as a driving source because it expands and contracts with extremely responsiveness to an applied voltage, but has a very small displacement. For example, even in a laminated piezoelectric body formed by laminating about 100 disc-shaped piezoelectric bodies, the displacement is about several tens of microns.
At the practical stage, the displacement is expanded and used.

[0004] An enlargement mechanism using the so-called Palcal principle has been conventionally used as a mechanism for enlarging the minute displacement of the laminated piezoelectric body. This means that the displacement of a large-area piston driven by the expansion and contraction of a laminated piezoelectric body is transmitted to a small-area piston through hydraulic oil and expanded to a displacement corresponding to the cross-sectional area ratio. (For example, see “Hydraulic switching valve with piezoelectric actuator” in JP-A-1-313283). This allows
A displacement of the laminated piezoelectric body of several tens of microns can be obtained from a piston having a small cross-sectional area as a displacement of about 1 mm. The damping force switching valve is moved by the small cross-sectional area piston, and the damping force is switched by connecting or disconnecting the upper and lower oil chambers.

[0005]

However, the conventional example in which the above-mentioned laminated piezoelectric body and the displacement enlarging mechanism are combined has a displacement enlarging mechanism using Pascal's principle in addition to the damping force switching mechanism. , They both have a precision structure. The conventional displacement enlargement mechanism uses a cylinder and piston with the least possible oil leakage, but if the hydraulic oil in the cylinder still leaks, the stroke of the small cross-section piston, which originally has a displacement of only about 1 mm, decreases. As a result, a normal switching operation cannot be performed.

For this reason, it is necessary to provide a check valve mechanism for compensating the outflow of hydraulic oil from the cylinder, and to supply oil into the cylinder via the check valve when the hydraulic oil in the cylinder runs short. The structure became complicated, leading to an increase in cost. Further, even if the displacement of the laminated piezoelectric body is controlled by an applied voltage or the like, the position of the damping force switching valve cannot be fixed at a constant value due to the leakage of the hydraulic oil, so that the damping force is continuously optimized. It could not be switched and controllability was poor.

Further, since the enlargement rate of the displacement is determined by the cross-sectional area ratio between the piston having a large cross-sectional area and the piston having a small cross-sectional area, the cross-sectional area ratio must be increased to 30 times in order to obtain an enlargement rate of 30 times. There is. Therefore, a small cross-sectional area piston and a large cross-sectional area piston having 30 times the cross-sectional area are always required, and the size of the small cross-sectional area piston cannot be extremely reduced. It gets bigger.

Accordingly, an object of the present invention is to provide a switchable flow path area variable mechanism and a shock absorber damping force switching mechanism that can be switched with a simple configuration and a relatively small required space. And

[0009]

Means for Solving the Problems] flow area varying mechanism of the present invention in order to solve the above problems, the piezoelectric body expands and contracts in accordance with the indicia pressurized voltage, provided in the fluid passage, the piezoelectric body A sliding member slidable in the direction of expansion and contraction, and provided in a plate shape and provided substantially parallel to the sliding direction of the sliding member, one end of which has a fixed position and the other end corresponds to the sliding member. A plurality of switching flexible plates having elasticity whose positions can be changed, and the plurality of switching flexible plates are substantially parallel to each other, and are opposed to each other when no voltage is applied to the piezoelectric body. Is arranged so that an initial deflection occurs, and further, a valve is arranged between the plurality of switching deflection plates,
The valve includes a valve outer and a slidable valve inner provided in the valve outer, and the valve outer and the valve inner are movable by bending of the separate switching bending plates, respectively. An opening hole is formed on one of the side surfaces, and the opening hole is closed by the side surface of the other valve by the bending movement of the plurality of switching bending plates, so that the flow passage area of the fluid passage is reduced. It is characterized in that it can be changed. Further, the damping force switching mechanism of the shock absorber according to the present invention includes an oil passage communicating the two oil chambers defined by the piston slidably fitted to the cylinder, and changes a flow passage area of the oil passage. A damping force switching mechanism of a shock absorber capable of switching a damping force by driving a piezoelectric body that expands and contracts in accordance with an applied voltage, including a sliding member slidable in the cylinder axis direction, And has two elastic flexible switching plates, one end of which is fixed in position and the other end of which is in contact with the sliding member. The two flexure plates for switching are arranged in parallel so that initial flexure is generated in a direction facing each other when no voltage is applied to the piezoelectric body, and a valve is provided between the two flexure plates for switching. Place The valve includes a valve outer and a slidable valve inner provided in the valve outer, and the valve outer and the valve inner are movable by bending of the separate switching bending plates, respectively. An opening hole is formed on one of the side surfaces, and the opening hole is closed by the side surface of the other valve by the bending movement of the two switching bending plates, so that the flow area of the oil passage is increased. Can be changed.

[0010]

According to the variable channel area mechanism and the damping force switching mechanism of the shock absorber of the present invention, when a voltage is applied to expand the piezoelectric body, the sliding member slides in the cylinder axis direction. Then, the switching flexible plate pressed by the sliding member has an end on the side in contact with the sliding member approaching the other end. By thus distance between the ends is shortened, I two switching deflection plate opposite was even on the side where initial deflection has occurred no. Then, it is placed between the switching flexures
The valve outer and the valve inner that make up the valve
Each is moved by the deflection of the switching
Formed on either side of outer or valve inner
The opened hole is closed. Thereby, the flow passage area of the oil passage such as the fluid passage can be changed.

On the other hand, when the application of the voltage is stopped, the piezoelectric body returns to the original state, and the switching flexible plate returns to the original initial bending state by its own elastic restoring force. Accordingly, the valve returns to the original position, and the flow path area returns to the original state.
Here, the relationship between the displacement in which the distance between both ends of the switching flexible plate is reduced and the amount of deflection of the switching flexible plate, that is, the displacement enlargement ratio, will be described. First, the deflection plate is assumed to be a part of a circular arc, and the displacement enlargement ratio k1 will be described with reference to FIG. Let R be the radius of curvature in the initial deflection state (indicated by the symbol a in the figure), and r be the radius of curvature after the linear distance between both ends of the arc has been reduced by the displacement Δx (indicated by the symbol b in the figure). Assuming that the displacement of the center of the arc is k1 △ x, FIG.
From the geometric relationship shown in (A), the displacement magnifying power k1 is expressed by the following equation.

[0012]

(Equation 1)

FIG. 6B is a graph showing the relationship between the radius of curvature R, the angle θ in FIG. 6A, and the displacement magnifying power k1 when the displacement Δx = 0.025 mm. As can be seen from this graph, when considered as an arc,
An enlargement factor of up to about 20 times can be obtained.

Next, the displacement magnification k2 when the degree of deflection near the center of the bending plate can be approximated by a triangle, such as when the degree of deflection is larger than the other portions, will be described with reference to FIG. From the initial deflection state (indicated by the symbol c in the figure), the linear distance between both ends is reduced by the displacement Δx (the symbol d in the figure).
Indicated by ) Is k2 · △ x, the displacement magnification k2 is given by the geometric relationship shown in FIG.
It is shown as the following equation.

[0015]

(Equation 2)

Then, Δx = 0.025 mm, L = 20
FIG. 7B is a graph showing the relationship between the angle θ and the displacement magnification k2 in FIG. As can be seen from this graph, when considered as a triangle, 2
An enlargement factor of up to about 5 times can be obtained.

As described above, the minute displacement of the piezoelectric body is enlarged by the flexure for switching and the damping force switching valve is moved by the flexure of the flexure for switching to change the area of the flow path. in yet possible to space requirements also relatively decreased, sufficient displacement enlargement factor also obtained, in particular, a flow path area varying mechanism of the present invention shock absorber
In the case where the damping force is adopted, the width of the switchable damping force can be set large and the damping force controllability can be improved.

[0018]

Embodiments of the present invention will be described below. In this embodiment, an example in which the present invention is applied to a variable damping force type shock absorber that is provided together with a coil spring between a wheel and a vehicle body will be described. FIG. 1 is a sectional view showing details of a damping force switching mechanism of the shock absorber of the present embodiment, and FIG. 2 is a partially broken sectional view of the shock absorber.

As shown in FIG. 2, the shock absorber SA is fixed to the axle-side member 5 at the lower end on the first cylinder 3 side, while being connected to the upper end on the rod 7 side via a bearing 9 and a vibration-proof rubber 11. And is fixed to the vehicle body side member 13.
A rod 7 is fitted into the first cylinder 3, and a hollow second cylinder 15 is connected to a lower end of the rod 7. A substantially cylindrical housing 17 is screwed into the second cylinder 15, and a main piston 20 slidable along the inner peripheral surface of the first cylinder 3 is screwed into a lower end of the housing 17. Have been.

The outer periphery of the main piston 20 has an O-ring 19
The main piston 20 separates the inside of the first cylinder 3 into an upper oil chamber 21 and a lower oil chamber 23, and the hydraulic oil filled in the first cylinder 3 is vertically The two oil chambers 21 and 23 are separated.

Therefore, when the main piston 20 slides in the first cylinder 3 in the axial direction indicated by arrows A and B in the figure, the hydraulic oil in the upper oil chamber 21 and the lower oil chamber 23 is supplied to the orifice 20a. Flow through each other, and the cross-sectional area of the orifice determines the damping force of the shock absorber SA when not controlled. still,
The damping characteristic when the hydraulic oil flows only through the orifice 20a is a characteristic with a large damping force (hard) because the flow path cross-sectional area is relatively small and the flow rate is small.

On the other hand, the second cylinder 15 and the housing 17
From the upper end of the hollow portion formed by the above, a piezo load sensor 25 for detecting the magnitude of the force acting on the shock absorber SA, a laminated piezoelectric body 27 in contact with the lower end of the piezo load sensor 25, and a laminated type First pistons 30 that are in contact with the lower ends of the piezoelectric bodies 27 are sequentially incorporated.

In the center of the housing 17, a first
Sliding hole 24 in which sliding protrusion 30a of piston 30 can slide.
Is provided. The first piston 30 has a preset spring 3
5 and the sliding projection 30a is inserted in the sliding hole 24. The preset spring 35 is a disc-shaped spring that is installed in a crushed state and applies a pressing force to the laminated piezoelectric body 27 via the first piston 30.

The sliding projection 30a of the first piston 30
An O-ring 37 is provided between the housing 26 and the partitioning portion 26 of the housing 17 so that the operating oil does not enter the stacked piezoelectric body 27. On the opposite side of the laminated piezoelectric body 27 across the partition portion 26, the second piston 40, the base 43, the valve mechanism 70, the cylinder end rod 48, the switching flex plate (hereinafter simply referred to as flexure) as a sliding member in the present invention. 45 etc. are stored. The second piston 40 has a disk shape and is slidable in the axial direction along the inner periphery of the housing 17.

The flexible plate 45 is a rectangular plate made of a spring steel plate or the like, and has an opening 45a at the center. In the present embodiment, two flexible plates 45 are used and the second
A flange 4 provided below the piston 40 and the base 43
4 is sandwiched in a state where the central portion thereof is slightly bent inward in advance. That is, the two flexure plates 45 are arranged such that their initial flexures face each other.

The collar 44 is provided with an engaging groove 44a for positioning the end of the flexible plate 45. In this embodiment, as shown in FIG. 3A, the end surface of the flexible plate 45 and the bottom of the engaging groove 44a are formed in a curved surface, and the flexible plate 45 itself swings around the end surface of the flexible plate 45 as a fulcrum. It is easy to move. On the other hand, as shown in FIG. 3B, the second piston 40 is also provided with a similar engagement groove 40a, and the engagement groove 40a and the end surface of the flexible plate 45 to be engaged are also curved. I have.

Here, a method of giving the initial flexure to the flexure plate 45 will be described. In this embodiment, a screw is formed on the outer periphery of the end rod 48, and the end rod 48 can be screwed in from the lower end of the housing 17. Since the base 43 is merely placed on the end rod 48, when the end rod 48 is screwed in, the distance between the second piston 40 and the flange portion 44 of the base 43 is shortened. Can be deflected. A lock nut 47 is provided to fix the position of the end rod 48 when the amount of deflection of the bending plate 45 reaches a desired state.

Next, the structure of the valve mechanism 70 disposed inside the base 43 and its surroundings will be described. FIG. 4 is an enlarged sectional view of the periphery of the valve mechanism 70, and FIG. 5 is an exploded view of the valve mechanism 70. As shown in FIG. 4, the base 43 is provided with a horizontal hole 51 whose axis is a line connecting substantially the vertices of the two flexible plates 45.
The third cylinder 71 is press-fitted. Further, a through hole 73 through which hydraulic oil passes is provided in a part of the side surface of the third cylinder 71, and communicates with a vertical hole 53 provided along the axial direction in the base 43. Note that the third cylinder 71 may not be provided as long as the above-described lateral hole 51 of the base 43 can be processed with high precision.

In the third cylinder 71, a third cylinder 7
A valve outer 75 having an outer diameter that is only slightly smaller than the inner diameter of the first cylinder (with a clearance of about 1 to 6 μm) and that can slide freely in the third cylinder 71 along the axis of the lateral hole 51.
Is arranged. The valve outer 75 has a substantially cylindrical shape.
The third cylinder 7 is provided in the groove 77.
A communication hole 79 that is an opening of the present invention and that communicates with one through hole 73 is provided. An outer flange portion 83 for receiving a return spring 81 described later is formed on one end side of the valve outer 75 inward.

The valve outer 75 has an outer diameter slightly smaller than the inner diameter of the valve outer 75 (the clearance is about 1 to 6 μm), and can slide freely in the valve outer 75 along the axis of the lateral hole 51. A simple valve inner 85 is arranged. The valve inner 85 also has a substantially cylindrical shape, and an inner flange 87 for receiving the return spring 81 is formed inward at one end located on the opposite side to the outer flange 83 provided on the valve outer 75. ing.

The valve outer 75 and the valve inner 85 are
The springs are urged outward by the reaction force of the return spring 81, and their movements are restricted while being pressed near the apex of the flexible plate 45. With no voltage applied to the laminated piezoelectric body 27, the valve inner 85
The distance between the end face EF1 on the opposite side of the inner flange 87 and the end face EF2 of the groove 77 of the valve outer 75 is twice as large as the displacement (= x) after the expansion obtained by the flexible plate 45. The initial deflection given to the deflection plate 45 is adjusted.

Therefore, the end face EF of the valve inner 85
The area S of the flow path formed between the valve 1 and the end face EF2 of the groove 77 of the valve outer 75 is represented by the following equation (1). S = 2πR · 2x (1) R: outer radius of the valve inner 85 2x: clearance between both end surfaces EF1, EF2 Returning to FIG. 1, the end rod 48 also has a through hole 46 formed in the axial direction, and the housing When the end rod 48 is screwed into the base 17, the vertical hole 53 of the base 43 and the through hole 46 of the end rod 48 are positioned so as to communicate with each other. Further, when the hydraulic oil flows from the vertical hole 53 of the base 43 through the through hole 46 of the end rod 48, between the base 43 and the end rod 48,
An O-ring 49 is provided.

On the other hand, when the end rod 48 is screwed into the upper end of the base 43, the flexible plate 45 is
A positioning projection 55 having a square cross section is provided so as to rotate together with the piston 40. The second piston 40 is provided with a square hole 41 with which the positioning projection 55 is engaged.

Further, the positioning projection 55 and the square hole 4 are provided so that the second piston 40 is not obstructed when moving.
There is a slight gap between the bottom of the first and the bottom. However,
When screwing the end rod, the positioning projection 55 may be omitted if a jig or the like is devised and assembled so that the flexible plate is not twisted.

When one of the wheels of the vehicle attempts to pass through a recess, for example, the shock absorber SA senses the impact with the damping force sensor 25 and does not show that the vehicle is passing through the recess. This is a well-known system that notifies the ECU and applies a voltage to the laminated piezoelectric body 27. Therefore, in the shock absorber SA, when the wheel passes through the concave portion or the convex portion, a voltage is immediately applied to the laminated piezoelectric body 27.

Next, the shock absorber SA having the above-described configuration will be described.
The operation of will be described. First, the flow of hydraulic oil will be briefly described. Now, assume that the wheel is about to pass through the recess. When the wheel passes through the recess,
The position of the first cylinder 3 shown in FIG. That is,
The working oil in the first cylinder 3 which is divided into the upper oil chamber 21 and the lower oil chamber 23 by the main piston 20 cannot keep up with the rapid volume change because the volume of the upper oil chamber 21 becomes small. The pressure in the upper oil chamber 21 increases as compared with that in the lower oil chamber 23.

At this time, the high-pressure hydraulic oil in the upper oil chamber 21 flowing into the housing 17 through the communication hole 60 provided in the housing 17 is supplied to the opening 45 of the flexible plate 45.
a, or flows into the valve inner 85 through the space between the flexible plate 45 and the base 43. The hydraulic oil is supplied to the end face EF1 of the valve inner 85 and the groove 77 of the valve outer 75.
Of the valve outer 75, the through hole 73 of the third cylinder 71, the base 4
3, and sequentially flows into the lower oil chamber 23 through the through hole 46 of the end rod 48. The pressure of the upper oil chamber 21 gradually decreases as the high-pressure hydraulic oil in the upper oil chamber 21 flows into the lower oil chamber 23 gradually.

Conversely, when the wheel passes through the convex portion, the position of the first cylinder 3 shown in FIG. 1 rapidly rises in the direction A in the figure relative to the position of the main piston 20. That is, the hydraulic oil in the first cylinder 3 divided into the upper oil chamber 21 and the lower oil chamber 23 by the main piston 20 has a smaller volume in the lower oil chamber 23, so that it can keep up with its rapid volume change. Instead, the pressure in the lower oil chamber 23 rises compared to that in the upper oil chamber 21 and flows in a direction opposite to the flow of the hydraulic oil described above.

Next, switching of the damping force when the hydraulic oil flows as described above will be described. As the wheel passes through the concave portion, a voltage is applied to the laminated piezoelectric body 27, and a displacement is generated on the extension side. Then, the first piston 30 is pushed down against the preset spring 35. Normal,
Since the second piston 40 is pressed against the first piston 30 by the bending force of the bending plate 45, the second piston 40 is pushed down in the axial direction by the displacement of the laminated piezoelectric body 27 in synchronization with the movement of the first piston 30.

Therefore, the second piston 40 and the base 4
3 becomes shorter, and the flexure plate 45
Is bent further inward (in the direction of the white arrow shown in FIG. 4) than the initial bending state. In this case, the deflection amount is about 10 to 25 times larger than the displacement of the multilayer piezoelectric body 27. The principle of the displacement enlargement has also been described in the above-mentioned section of “action”, so that detailed description will be omitted. Since the opening 45a is provided at the center of the flexible plate 45 of this embodiment, the cross-sectional area of the opening 45a is reduced, the degree of bending is increased, and the bending plate 45 approaches the triangle approximation.

When the displacement after expansion (ie, the amount of deflection) enlarged by one flexible plate 45 is x, the distance between the vertices of the two flexible plates 45 is reduced by 2x. Therefore, the end face EF1 of the valve inner 85
And the clearance between the end face EF2 of the groove 77 of the valve outer 75 is "0", and as can be seen from the above equation (1), the flow path area is also "0".

On the other hand, when the application of the voltage is stopped, the multi-layer piezoelectric body 27 returns to the original state.
Returns to the original initial bending state by its own elastic restoring force, and the damping force also returns to the original state. Therefore, the damping force of the shock absorber SA is reduced by the soft state where the flow path area S is the largest when no voltage is applied to the multilayer piezoelectric body 27 and when the voltage is not applied to the multilayer piezoelectric body 27.
It is possible to switch between the hard state having the smallest flow path area S (S = 0 in this embodiment).

As described above, since the minute displacement of the laminated piezoelectric element 27 is enlarged by the flexure plate 45 and the valve outer 75 and the valve inner 85 are moved by the flexure of the flexure plate 45, the flow path area S is changed. With a simple configuration, the required space can be relatively reduced, a sufficient displacement enlargement ratio can be obtained, the width of the switchable damping force can be set large, and the damping force controllability can be improved.

Also, the applied piezoelectric material 27
Is determined, the position of the valve outer 75 and the valve inner 85 can be arbitrarily determined by controlling the applied voltage, and the damping force can be maintained between the hard state and the soft state. Therefore, it is possible to continuously control the damping force by the applied voltage.

As described above, the present invention is not limited to such an embodiment, and can be carried out in various modes without departing from the gist of the present invention. For example, if the thickness of the central portion of the flexible plate 45 is reduced, the degree of bending of the central portion of the flexible plate 45 is further increased, and the deflection plate 45 is closer to triangular approximation, so that a larger displacement magnification can be obtained. The same effect can be obtained by reducing the width of the flexible plate 45 instead of reducing the thickness.

[0046]

As described above, the flow path area of the present invention is
According to the variable mechanism and the damping force switching mechanism of the shock absorber, the minute displacement of the piezoelectric body is expanded by the flexure for switching, and the flexure for the switching flexure moves the damping force switching valve to change the flow path area. order to perform, yet can also be relatively small space requirement with a simple structure, sufficient displacement enlargement factor also obtained, in particular, shock
When used for a absorber, there is an effect that the width of the switchable damping force can be set large and the damping force controllability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing details of a damping force switching mechanism of a shock absorber according to one embodiment of the present invention.

FIG. 2 is a partially broken sectional view of a shock absorber.

3A is a cross-sectional view illustrating an engagement state between a base flange portion and a flexible plate, and FIG. 3B is a cross-sectional view illustrating an engaged state between a second piston and a flexible plate.

FIG. 4 is an enlarged sectional view of a peripheral portion of a valve mechanism.

FIG. 5 is a sectional view of a valve mechanism.

FIG. 6A is an explanatory diagram showing a geometric relationship when a flexible plate is approximated by an arc, and FIG. 6B is a graph showing a relationship between a curvature radius R and an angle θ and a displacement magnification k1.

FIG. 7A is an explanatory diagram showing a geometric relationship when a flexible plate is approximated by a triangle, and FIG. 7B is a graph showing a relationship between an angle θ and a displacement magnification k2.

[Description of Signs] 3 ... First cylinder, 17 ... Housing, 20 ...
Main piston, 21: Upper oil chamber, 23: Lower oil chamber, 27: Laminated piezoelectric body, 30: First piston, 30a: Sliding protrusion, 40: Second piston,
43 ... base, 44 ... collar, 45
... flexure plate, 45a ... opening, 51 ... side hole,
53 ... vertical hole, 70 ... valve mechanism, 71
... 3rd cylinder, 73 ... Through hole, 75 ... Valve outer, 77 ... Groove, 79 ... Communication hole, 81
... Return spring, 83 ... Outer flange, 85
... Valve inner, 87 ... Inner collar

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Moriwaki 1-1-1 Showa-cho, Kariya-shi, Aichi Japan Inside Denso Corporation (72) Inventor Hirokatsu Mukai 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Japan Denso Stock In-house (72) Inventor Naoto Miwa 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References Japanese Utility Model Showa 61-58748 (JP, U) Japanese Utility Model Showa 61-147405 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F16F 9/46 B60G 13/08

Claims (3)

(57) [Claims] A piezoelectric body expands and contracts in accordance with claim 1] indicia pressurized voltage, provided in the fluid passageway, and slidable slide member in the elongating and contracting direction of the piezoelectric body, the sliding is formed in a flat plate It is provided substantially parallel to the sliding direction of the member, one end of which has a fixed position, and the other end has a plurality of resilient switching flexible plates whose position can be changed corresponding to the sliding member, and The plurality of switching flexures are substantially parallel to each other,
When no voltage is applied to the piezoelectric body, the piezoelectric element is arranged so that initial deflections are generated in directions facing each other. Further, a valve is arranged between the plurality of switching deflection plates, and the valve includes a valve outer and the valve outer. The valve outer and the valve inner are respectively movable by bending of the separate switching bending plate, and an opening hole is formed on one side surface of the valve outer or the valve inner. Is formed, and the opening area is closed by the side surface of the other valve by the bending movement of the plurality of switching bending plates, so that the flow passage area of the fluid passage can be changed. Variable flow area mechanism. 2. The other end of the switching flexible plate is connected to the sliding member.
2. The flow according to claim 1, wherein the flow is in contact with the member.
Road area variable mechanism. 3. An oil passage communicating two oil chambers defined by a piston slidably fitted to a cylinder,
A damping force switching mechanism of a shock absorber capable of switching a damping force by changing a flow passage area of the oil passage, driven by a piezoelectric body that expands and contracts in accordance with an applied voltage, and slides in a cylinder axial direction. comprising a sliding member capable of being formed into a flat plate shape are substantially parallel to the sliding direction of the sliding member, one end of the other end position is fixed is in contact with the sliding member, elastic has two switching for flexure plate having them two switching deflection plates parallel and, together with the at the time of non-application state to the piezoelectric member arranged so that the initial deflection occurs in the direction opposite to each other, the A valve is placed between two switching flexures , and
The valve is provided with a valve outer and the valve outer.
Re consists slidable Barubuin'na, the Bal Buauta
And the valve inner is a separate flexure plate for switching.
Each valve can be moved by bending,
Open on either side of the
A hole is formed, and the opening is formed by the bending movement of the two switching bending plates.
The hole is closed by the side of the other valve.
A damping force switching mechanism for the shock absorber , wherein the flow passage area of the oil passage is variable.