JP2006161893A - Shock absorber for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorber capable of controlling damping force in response to a vertical force with a simple structure. <P>SOLUTION: The shock absorber 1 comprises: a mass member 53 moved by the vertical force generated in a vehicle; bypass passages 34, 35 and 36 allowing a first liquid chamber and a second liquid chamber defined by a piston valve, and a reservoir chamber to communicate with each other; a spool 42 for opening/closing the bypass passages 34, 35 and 36; and a spool operation part 50 acting as a connection mechanism which connects the spool 42 and the mass member 53 and brings the spool 42 from a valve-opened state to a valve-closed state in association with the movement of the mass member 53 caused by the vertical force generated in the vehicle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle shock absorber used for a vehicle suspension, and is suitable for a vehicle shock absorber capable of changing a damping force in accordance with a vertical force generated in the vehicle.

Such a vehicle shock absorber includes a damping force variable mechanism, detects the acceleration in the vertical direction of the sprung member in the suspension mechanism with an acceleration sensor, and calculates the vertical velocity on the spring from the vertical acceleration. Some control the damping force by the variable damping force mechanism based on the calculated sprung vertical speed and the detected sprung vertical acceleration (for example, Patent Document 1).
Japanese Patent Laid-Open No. 4-15133

However, in the conventional vehicle shock absorber, an acceleration sensor is used to detect the sprung vertical acceleration, and an arithmetic processing unit is further used for calculating the sprung vertical speed and controlling the night damping force in the damping force variable mechanism. Since it is necessary, there is a problem of high cost.
The present invention has been developed to solve these various problems, and an object of the present invention is to provide a vehicle shock absorber capable of reducing the cost.

  In order to solve the above-described problems, a vehicle shock absorber according to the present invention includes a piston rod connected to a vehicle body side member, a cylinder connected to a wheel side member, which is composed of an inner cylinder and an outer cylinder, and the inner cylinder. A piston connected to the piston rod inserted from the one end side of the cylinder, and the second formed on the other end side of the cylinder, and is provided in the inner cylinder so as to partition into one chamber and a second chamber A first valve that allows hydraulic fluid to flow between a chamber and a reservoir chamber provided in a gap between the inner cylinder and the outer cylinder; and a piston that is provided between the first chamber and the second chamber. A shock absorber for a vehicle including a second valve for flowing hydraulic fluid, a mass member that is moved by a vertical force generated in the vehicle, a first flow path that communicates the first chamber and the second chamber, The second chamber and the reservoir chamber; A second flow path to be communicated, an on-off valve for opening and closing the first flow path and the second flow path, the on-off valve and the mass member, and the on-off valve interlocked with the movement of the mass member by the vertical force And a connecting mechanism for switching the open / closed state of the.

  As a result, when the vertical shock is not generated in the vehicle, the shock absorber for the vehicle opens the open / close valve so that the first chamber, the second chamber, and the reservoir chamber are in communication, and the damping force is reduced. Get smaller. On the other hand, when vertical force is generated in the vehicle, the on-off valve is closed, so that the communication between the first chamber and the second chamber and the communication between the second chamber and the reservoir chamber are both blocked and attenuated. Strength increases. That is, even if the vertical force is not detected by the sensor, the damping force achieved is a vertical force sensitive type.

  Thus, according to the vehicle shock absorber of the present invention, the vertical acceleration sensor and the arithmetic processing device are not required, and the cost can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 are schematic configuration diagrams showing a first embodiment of a vehicle shock absorber according to the present invention. FIG. 1 is a view of an upright shock absorber 1 as seen from the vehicle longitudinal direction, for example, and FIG. 2 is a view of the upright shock absorber 1 as seen from the vehicle width direction, for example. In addition, the layout of the upright shock absorber 1 is not limited to this, and the orthogonal view from the side including the front-rear direction of the vehicle only needs to have a relationship as shown in FIGS.

The shock absorber 1 includes a cylinder 4 having an inner cylinder 2 and an outer cylinder 3, a piston valve 5 inserted in the inner cylinder 2 so as to be slidable in the axial direction of the inner cylinder 2, and a piston valve 5 having a lower end. The connected piston rod 6 and the damping force control part 30 which controls damping force are provided.
A base valve 8 is provided at the bottom of the cylinder 4 so as to close the inner cylinder 2 and the outer cylinder 3. In the cylinder 4, a reservoir chamber 7 is formed between the inner cylinder 2 and the outer cylinder 3, and hydraulic oil is filled in the reservoir chamber 7 and the inner cylinder 2. Moreover, the eyeball portion 9 at the lower end of the cylinder 4 is connected to a wheel side (not shown).

The piston valve 5 partitions the inside of the cylinder 4 (specifically, the inner cylinder 2) into an upper first liquid chamber 10 and a lower second liquid chamber 11. The piston valve 5 is provided with a damping force generator.
When the piston valve 5 moves in the inner cylinder 2, the damping force generation unit is used when the differential pressure between the pressure in the first liquid chamber 10 and the pressure in the second liquid chamber 11 becomes larger than a predetermined pressure. The valve is opened and the damping force is changed.

In the cylinder 4, when the piston valve 5 slides in the inner cylinder 2, the hydraulic oil flows through the piston valve 5, and the hydraulic oil flows in the inner cylinder 2 and the reservoir chamber 7 through the base valve 8. And is supposed to flow. The shock absorber 1 generates a predetermined damping force by the flow of these hydraulic oils.
Further, the first liquid chamber 10 and the second liquid chamber 11 and the reservoir chamber 7 of the cylinder 4 are respectively connected to the damping force via the bypass paths 34, 35, and 36 of the damping force control unit 30 as described later. It communicates with the control unit 30.
The upper end of the piston rod 6 is connected to the vehicle body side 13 via an insulator rubber 12.

3 and 4 show a detailed configuration of the damping force control unit 30. FIG. The configuration of the damping force control unit 30 shown in FIGS. 3 and 4 is a configuration viewed from the same direction as FIG.
As shown in FIGS. 3 and 4, the damping force control unit 30 includes a spring 32, an attenuator 33, a bypass communication on / off unit 40, and a spool operation unit 50 in a case 31.
The bypass passage communication ON / OFF portion 40 includes, for example, a cylindrical spool storage portion 41 that is long in the vehicle front-rear direction, and a substantially cylindrical spool (spool valve) 42 that is stored in the spool storage portion 41. ing.

  First to third bypass passages 34, 35, and 36 are connected to the spool storage portion 41 at predetermined positions. The first bypass path 34 is connected to the first liquid chamber 10 of the cylinder 4, the second bypass path 35 is connected to the second liquid chamber 11 of the cylinder 4, and the third bypass path 36 is connected to the cylinder 4 reservoir chambers 7. In this embodiment, the first bypass path 34 and the third bypass path 36 are connected to a portion of the spool storage portion 41 that is lined up in the vehicle front-rear direction, and the second bypass path 35 is the first of these in the spool storage portion 41. It is connected to a part facing the part to which the bypass path 34 and the third bypass path 36 are connected.

With such a structure, the spool storage portion 41 communicates with the first and second liquid chambers 10 and 11 and the reservoir chamber 7 via the first to third bypass passages 34, 35 and 36. In addition, the spool storage portion 41 and the first to third bypass passages 34, 35, and 36 are filled with hydraulic oil, similarly to the first and second liquid chambers 10 and 11 and the reservoir chamber 7.
As shown schematically in FIGS. 5 and 6, an oil passage 43 is formed on the outer peripheral surface of the spool 42. The oil passage 43 is formed on one end side of the spool 42 as shown in FIGS. The oil passage 43 has a portion 43a having one end communicating with the first bypass passage 34, a portion 43b having the second bypass passage 35 communicated with one end, and a portion 43c having one end communicated with the third bypass passage 36. It consists of and.

  As shown in FIG. 3, when one end surface of the spool 42 abuts a side surface (hereinafter, referred to as a spring arrangement side surface) of the spring 32 and the attenuator 33 described later in the vehicle front-rear direction of the spool storage portion 41. In addition, as clearly shown in FIG. 5, the oil passage 43 and the bypass passages 34, 35, and 36 communicate with each other. Further, as shown in FIG. 4, the other end surface of the spool 42 abuts on a side surface (hereinafter referred to as a spool operation portion arrangement side side surface) of a spool operation portion 50 described later in the vehicle front-rear direction of the spool storage portion 41. In this case, as clearly shown in FIG. 6, the communication between the oil passage 43 and each bypass passage 34, 35, 36 is blocked. That is, the connection positions of the bypass passages 34, 35, 36 to the spool storage portion 41 and the shape of the oil passage 43 are the same as the oil passage 43 when the spool 42 is moved to a predetermined position in the spool storage portion 41. And each of the bypass passages 34, 35, 36 are designed to be in a communication state or in a state where the communication is blocked.

  In addition, a first rod 45 is attached to the spool 42 on the end surface on the side where the oil passage 43 is formed, in the vehicle front-rear direction. Further, a second rod 46 that is a connecting rod is attached to the spool 42 at the other end side with a so-called play in the vehicle longitudinal direction with respect to the spool 42. Here, the first and second rods 45, 46 are inserted into the spool storage portion 41 from the side surface in the vehicle front-rear direction of the spool storage portion 41 and attached to the spool 42.

A spring 32 and an attenuator 33 attached to the spring 32 are attached to the end of the first rod 45. The spring 32 is for biasing the first rod 45, that is, the spool 42 toward the spring 32. As a result, when the biasing force by the spring 32 is applied, the spool 42 is moved by a predetermined damping force applied by the attenuator 33.
The second rod 46 is attached to the spool 42 with play in the vehicle front-rear direction by a space 44 formed inside the spool 42 near the other end. The space portion 44 has a cylindrical shape that is long in the moving direction of the spool 42, and is open to the end surface of the spool 42.

  The second rod 46 has a main body portion 46a inserted through the opening on the end face of the spool 42 into the space 44, and a piston portion 46b is integrally formed at one end of the inserted main body portion 46a. Yes. The piston portion 46 b is movable in the vehicle front-rear direction within the space portion 44. The other end of the main body 46 a of the second rod 46 is connected to the spool operation unit 50.

  The spool operation unit 50 is configured as a so-called connecting rod mechanism by rod-shaped first and second links 51 and 52. That is, the first link member 51 and the second link member 52 are rotatably connected to each other at one end, and the other end of the first link member 51 is rotatable to the other end of the main body portion 46 a of the second rod 46. Further, the other end of the second link member 52 is rotatably connected to a stationary part of the damping force control unit 30, for example, a pin 37 provided on the case 31. The spool operation unit 50 includes a mass member 53 at a connecting portion between the first link member 51 and the second link member 52.

In addition, the connection part of the 1st link member 51 and the main-body part 46a of the 2nd rod 46 is restrained so that it may move only to the vehicle front-back direction by the restraint member etc. which are not shown in figure.
The spool operating unit 50 configured as described above allows the mass member 53 to move in the vehicle vertical direction by the link mechanism formed by the first and second link members 51 and 52. That is, as shown as a change from FIG. 3 to FIG. 4, the mass member 53 can move in the vehicle up-down direction because the first link member 51 and the second link member 52 are bent. become able to. In conjunction with the operation of the first link member 51 and the second link member 52, the second rod 46 connected to the other end of the first link member 51 moves in the vehicle front-rear direction. Accordingly, the piston portion 46b of the second rod 46 moves in the vehicle front-rear direction within the space portion 44 of the spool 42.

Here, as shown in FIG. 3, in the state where the first link member 51 and the second link member 52 of the spool operating portion 50 are fully extended as a link mechanism, the end surface of the piston portion 46 b is the spring of the space portion 44. It does not contact the side surface of the arrangement side. That is, as shown in FIG. 7, the first link member 51 and the second link member 52 serve as a link mechanism in a state where the other end surface of the spool 42 is in contact with the side surface on the spool operation unit arrangement side of the spool storage unit 41. The length of the space portion 44 in the vehicle front-rear direction or the length of the second rod 46 is determined so that the piston portion 46b does not come into contact with the spring arrangement side surface of the space portion 44 even when it is fully extended. ing.
The damping force control unit 30 is configured as described above.

Next, the operation and damping force characteristics of the shock absorber 1 will be described. For example, when a wheel rides on a protrusion on the road surface, an upward external force acts on the mass member 53. As a result, as shown in FIG. 8a, the first link member 51 and the second link member 52 of the spool operation unit 50 are bent, and the second rod 46 is pulled toward the spool operation unit 50 side. Accordingly, the outer peripheral portion (radially convex portion) of the piston portion 46b of the second rod is the side surface on the spool operation portion arrangement side of the space portion 44, that is, the outer peripheral portion of the opening portion of the spool 42 through which the second rod 46 is inserted. 54, and the spool 42 moves until it contacts the side surface of the spool storage portion 41 on the side where the spool operation portion is disposed. At this time, the spool 42 moves in the spool housing portion 41 against the urging force of the spring 32 and the damping force of the attenuator 33.
Thereby, as shown in the said FIG.4 and FIG.6, the communication with the oil path 43 and each bypass path 34,35,36 is interrupted | blocked.

  The same operation is performed when the wheel passes through the road surface recess. That is, when the wheel reaches the road surface recess, a downward external force acts on the mass member 53. As a result, as shown in FIG. 8c, the first link member 51 and the second link member 52 of the spool operation unit 50 are bent, and the second rod 46 is pulled toward the spool operation unit 50 side. As a result, the outer peripheral portion of the piston portion 46b of the second rod comes into contact with the side surface of the space 44 where the spool operating portion is disposed, that is, the outer peripheral portion 54 of the opening of the spool 42 through which the second rod 46 is inserted. The spool storage unit 41 moves until it contacts the side surface on the spool operation unit arrangement side. Thereby, as shown in the said FIG.4 and FIG.6, the communication with the oil path 43 and each bypass path 34,35,36 is interrupted | blocked.

As described above, when the communication between the first fluid chamber 10, the second fluid chamber 11, and the reservoir chamber 7 of the cylinder 4 by the bypass passages 34, 35, and 36 is interrupted, the piston valve 5 The damping force generator and the base valve 7 are activated to generate a damping force in the shock absorber 1.
Specifically, when the shock absorber 1 contracts, that is, when the piston rod 6 or the piston valve 5 moves downward, the pressure between the first liquid chamber 10 and the second liquid chamber 11 is reduced. Due to the pressure difference, a damping force is generated in the shock absorber 1 due to the hydraulic fluid flowing from the second fluid chamber 11 to the first fluid chamber 10 via the damping force generating portion of the piston valve 5.

Further, the hydraulic oil flows from the second liquid chamber 11 to the reservoir chamber 7 through the base valve 8 due to the pressure difference between the pressure in the second liquid chamber 11 and the reservoir chamber 7, so that the damping force is reduced to the shock absorber. 1 occurs.
Further, when the shock absorber 1 extends, that is, when the piston rod 6 or the piston valve 5 moves upward, the pressure difference between the pressure in the first liquid chamber 10 and the pressure in the second liquid chamber 11 is caused. A damping force is generated in the shock absorber 1 due to the hydraulic fluid flowing from the first liquid chamber 10 to the second liquid chamber 11 via the damping force generating portion of the piston valve 5.

Further, the hydraulic oil flows from the reservoir chamber 7 to the second liquid chamber 11 via the base valve 8 due to the pressure difference between the pressure in the reservoir chamber 7 and the pressure in the second liquid chamber 11, so that the damping force is shocked. Occurs in the absorber 1.
On the other hand, as shown in FIG. 8b, when there is no vertical input to the wheels or when the vertical force is not acting on the vehicle in general, as in stable road running, The first link member 51 and the second link member 52 of the portion 50 are fully extended as a link mechanism. At this time, the spool 42 is in contact with the spring arrangement side surface of the spool storage portion 41 by the urging force of the spring 32. Accordingly, as shown in FIGS. 3 and 5, the oil passage 43 and the bypass passages 34, 35, and 36 are in communication with each other.

As a result, the first liquid chamber 10, the second liquid chamber 11, and the reservoir chamber 7 of the cylinder 4 are brought into a communicating state by the bypass passages 34, 35, and 36. Thereby, a damping force is generated when the shock absorber expands and contracts.
Specifically, when the shock absorber 1 contracts, that is, when the piston rod 6 or the piston valve 5 moves downward, the second bypass path 32, the oil path 43 of the spool 42 of the damping force control unit 30, The hydraulic oil in the second liquid chamber 11 flows into the first liquid chamber 10 via the first bypass path 31.

When the shock absorber 1 extends, that is, when the piston rod 6 or the piston valve 5 moves upward, the first bypass passage 41, the oil passage 43 of the spool 42 of the damping force control unit 30, the second The hydraulic oil flows into the first liquid chamber 10 through the bypass passage 42 and into the second liquid chamber 11.
A damping force is generated in the shock absorber 1 by the flow of the hydraulic oil. However, the damping force is smaller than the damping force generated in the shock absorber 1 when the vertical force is applied. As described above, the control of the damping force of the shock absorber 1 is a vertical force sensitive control generated in the vehicle, and the damping force after getting over the road surface unevenness is larger than the damping force during stable road running.

The damping force of the shock absorber 1 increases as the speed of the piston valve 5 increases. Moreover, the damping force of the shock absorber 1 is an absolute value, and is larger when contracted than when expanded.
FIG. 9 shows the relationship between the vertical acceleration (the magnitude of the vertical force) and the moving speed of the spool 42 in the spool storage portion 41. As shown in the figure, as the vertical acceleration increases, the moving speed of the spool 42 in the spool storage portion 41 increases. Thereby, for example, when the vertical acceleration is large, such as when passing through a large road surface protrusion, the moving speed of the spool 42 increases, and as a result, the damping force of the shock absorber 1 rises quickly and increases. In addition, when the vertical acceleration is small, such as when overcoming a small road surface undulation, the moving speed of the spool 42 becomes slow, and as a result, the damping force of the shock absorber 1 increases gently.

  FIG. 10 shows the relationship between the position of the spool 42 in the spool housing portion 41 and the damping force of the shock absorber 1. As described above, when the spool 42 moves in the spool storage portion 41, the oil passage 43 and the bypass passages 34, 35, and 36 communicate with each other or the communication is blocked. The function of the oil passage 43 at this time can be considered to be equivalent to the function of the orifice valve whose opening degree changes as the spool 42 moves in the spool storage portion 41.

  As shown in FIG. 10, when the spool 42 moves to the arrangement side of the spring 32 or the attenuator 33 in the spool housing portion 41, the orifice opening increases (becomes fully open), thereby causing the hydraulic oil to move. Easily flows into the oil passage 43 or hydraulic oil easily flows out of the oil passage 43. As a result, the damping force of the shock absorber 1 becomes a small value. On the other hand, when the spool 42 moves to the arrangement side of the spool operation unit 50 in the spool storage unit 41, the opening of the orifice is reduced (to the fully closed side), so that the hydraulic oil flows into the oil passage 43. Or the hydraulic oil does not easily flow out of the oil passage 43. As a result, the damping force of the shock absorber 1 becomes a large value.

As described above, the damping force of the shock absorber 1 changes in accordance with the position of the spool 42 in the spool storage portion 41.
Next, the damping force characteristic of the shock absorber 1 when overcoming a gentle continuous road surface unevenness will be described. When the vehicle gets over the gentle continuous road surface unevenness, the vertical force in the opposite direction, that is, the vertical acceleration is applied to the vehicle one after another.
As described above, since the second rod 46 is attached with a so-called play in the vehicle front-rear direction of the spool 42, the other end surface of the spool 42 is in contact with the side surface of the spool storage portion 41 on the side of the spool operation portion. Even in a state where the first link member 51 and the second link member 52 are fully extended as a link mechanism, the piston portion 46b does not come into contact with the spring arrangement side surface of the space portion 44.

  Therefore, as shown in FIG. 8a or FIG. 8c, when the spool 42 is in contact with the side surface of the spool storage portion 41 on the side where the spool operation portion is disposed, the vertical force on the vehicle, that is, the vertical acceleration is applied. In the normal state, as shown in FIG. 8b, the second rod is also used when the first link member 51 and the second link member 52 of the spool operating portion 50 are extended as a link mechanism. 46 moves ahead of the spool 42 in the vehicle front-rear direction, and the piston portion 46 b of the second rod 46 is positioned at a substantially central portion in the longitudinal direction of the space portion 44. At this time, the spool 42 moves inside the spool housing portion 41 at a speed set by the elastic force of the spring 32 and the damping force of the attenuator 33 or at a speed depending on the elastic force of the spring 32 and the damping force of the attenuator 33. Moving.

  For example, as described above, the spool 42 moves in the spool housing portion 41 depending on the elastic force of the spring 32 and the damping force of the attenuator 33. During the movement, the second rod 46 is moved by the spool operating portion 50. When movement is started to the side, that is, for example, when a vertical force in the reverse direction, that is, vertical acceleration is applied, the piston portion 46b of the second rod 46 comes into contact with the side surface of the space portion 44 on the spool operation portion arrangement side. 42 is moved in the opposite direction from the middle of its movement, that is, before the state of communication with the first liquid chamber 10, the second liquid chamber 11, and the reservoir chamber 7 by the spool 32 is fully opened, it is again shifted to the fully closed direction. Therefore, the damping force of the shock absorber 1 changes from the decreasing direction to the increasing direction before reaching the minimum value.

As described above, by attaching the second rod 46 to the spool 42 with so-called play in the longitudinal direction of the vehicle, the damping force of the shock absorber 1 reaches a minimum value even when traveling on a gentle continuous uneven road surface. Instead, the vicinity of the predetermined value with a large value is changed.
In other words, assuming that the second rod 46 is directly attached to the spool 42 without causing so-called play in the vehicle longitudinal direction, the spool 42 always moves in conjunction with the movement of the mass member 53. Become. In this case, the damping force of the shock absorber 1 fluctuates between the minimum value and the maximum value corresponding to the vertical force continuous in the reverse direction, that is, the vertical acceleration, and the road surface input cannot be effectively attenuated.

Next, the effect will be described.
As described above, the shock absorber 1 includes the bypass passages 34, 35, and 36, and the bypass passage communication ON / OFF portion 40 including the spool 42, the spool operating portion 50 configured as a connecting rod mechanism (connection mechanism), Thus, the damping force is controlled according to the vertical force generated in the vehicle. Thereby, the shock absorber 1 realizes damping force control with a simple configuration. FIG. 12a shows an image of a transient road surface protrusion. FIG. 12b shows the attenuation characteristic of vertical acceleration by the shock absorber 1 of the present embodiment by a solid line, and the vertical acceleration by the conventional shock absorber. The attenuation characteristic is indicated by a two-dot chain line. As described above, in the shock absorber 1 of the present embodiment, the larger the vertical force, that is, the vertical acceleration, the greater the damping force is expressed. When the vertical acceleration is small, the damping force is suppressed to a small value, so that the vertical force is input. In the initial stage, the vertical acceleration can be greatly attenuated. As described above, in the present embodiment, the damping force can be controlled according to the magnitude of the vertical force with a simple configuration, so that the vertical acceleration sensor and the arithmetic processing device are not required, and the cost can be reduced correspondingly. It becomes.

Moreover, since the damping force is small at the normal time when a large vertical force does not act, the shock is small and the riding comfort is excellent. In addition, the initial damping force on both the compression side and the extension side can be set to be significantly smaller than that of the conventional shock absorber.
Further, since it is only necessary to provide the outer cylinder 3 with a spool operation unit 50 including a bypass passage communication on / off unit 40 and a coupling mechanism, the degree of freedom in the design of the vehicle body, for example, the shape of the engine room can be increased. The suspension stroke can also be lengthened. That is, for example, it does not affect the component characteristics (hood height, upper mount characteristics, bumper bar characteristics, etc.) around the upper mount. In addition, no new additional parts are required on the vehicle body side.

  As described above, the attenuator 33 is attached to the end of the first rod 45 along with the spring 32 and the spring 32. Thus, the spool 42 is given a biasing force to the spring 32 side, that is, a position where the spool 42 is opened, and a damping force is given when the spool 42 moves. Thereby, it can prevent that the spool 42 vibrates in a moving direction. In particular, by decreasing the damping force of the attenuator 33 on the extension side and increasing it on the compression side, it is possible to moderate the decrease in the damping force when the spool 42 returns, that is, when moving in the valve opening direction.

Further, as described above, the second rod 46 is attached with a so-called play in the moving direction of the spool 42. As a result, even if the mass member 53 moves due to the vertical acceleration generated in the vehicle, the spool 42 does not move immediately. As a result, the damping force control unit 30 and the first liquid chamber 10 of the cylinder 4 The communication state between the second liquid chamber 11 and the reservoir chamber 7 is not frequently switched, that is, the damping force of the shock absorber 1 is not frequently switched.
In particular, when the vertical force in the reverse direction is continuously applied, the spool 42 does not move in conjunction with the movement of the mass member 53, and the spool 42 moves under the action of the spring 32 and the attenuator 33. It becomes like this. Thereby, as described above, the damping force of the shock absorber 1 is maintained in the vicinity of the predetermined value of a large value without reaching the minimum value.

  Next, a second embodiment of the vehicle shock absorber according to the present invention will be described. In the first embodiment, a case has been described in which the spool operating portion 50 that operates the spool 42 or the second rod 46 is configured as a so-called connecting rod mechanism including rod-shaped first and second link members 51 and 52. In the present embodiment, instead of this, as shown in FIG. 13, the spool operating portion 60 is provided in the crank portion 61, the connecting member 62 that connects the crank portion 61 and the second rod 46, and the crank portion 61. And the mass member 63. Here, the crank portion 61 is rotatably supported by a non-moving portion of the damping force control portion 30, for example, the case 31. And in the crank part 61, the mass member 63 is provided so that the attachment position of the connection member 62 may be opposed. When the spool 42 is in the fully open position (when in the oil passage communication position in FIG. 13b), the connecting member 62 and the second rod 46 are in a so-called extended state. That is, in this state, when a straight line connecting the spool 42 and the rotation center of the crank portion 61 is assumed, the connecting point between the connecting member 62 and the crank portion 61 is on or near this line.

In the spool operation unit 61 configured as described above, when the mass member 63 moves in the vertical direction of the vehicle, the crank unit 61 rotates, and the rotational motion is connected to the connection member 62 via the connection member 62. The second rod 46 is converted into a straight movement. As a result, in conjunction with the movement of the mass member 63, the piston portion 46b of the second rod 46 moves in the vehicle front-rear direction within the spool housing portion 41.
With this configuration, when a vertical force is applied to the vehicle, the shock absorber 1 operates as follows.

  When the vertical force is applied, as shown in FIG. 13a or 13c, the crank portion 61 rotates as the mass portion 63 moves in the vehicle vertical direction, and the second rod 46 moves in conjunction with the rotational motion. It is drawn toward the spool operation unit 61 side. As a result, the piston portion 46 b of the second rod 46 comes into contact with the spool operation portion arrangement side surface of the space portion 44 and moves until the spool 42 comes into contact with the spool operation portion arrangement side surface of the spool storage portion 41.

  Accordingly, as in the first embodiment, as shown in FIGS. 4 and 6, the communication between the oil passage 43 and each bypass passage 34, 35, 36 is blocked, and the first liquid chamber 10 of the cylinder 4 is blocked. The second fluid chamber 11 and the reservoir chamber 7 are disconnected from each other, and when the shock absorber is expanded or contracted, the damping force generating portion of the piston valve 5 and the base valve 8 are operated to generate a damping force in the shock absorber. To do.

  On the other hand, when the vertical force does not act on the vehicle, the spool 42 comes into contact with the spring arrangement side surface of the spool storage portion 41 by the biasing force of the spring 32 as shown in FIG. Thus, as in the first embodiment, as shown in FIGS. 3 and 5, the oil passage 43 and the bypass passages 34, 35, and 36 are in communication with each other, and the first liquid chamber 10 of the cylinder 4 is in communication. The second fluid chamber 11 and the reservoir chamber 7 communicate with each other through the bypass passages 34, 35, and 36, and a damping force is generated when the shock absorber 1 is contracted. The damping force of the shock absorber 1 generated at this time is This is smaller than the damping force generated in the shock absorber 1 when the vertical force is applied.

  Further, in this embodiment, when the spool 42 is in the fully open position (the oil passage communication position shown in FIG. 13 b), the connection point between the connection member 62 and the crank portion 61 is the rotation center of the spool 42 and the crank portion 61. Therefore, the moving speed in the valve closing direction from the fully open position of the spool 42 due to the movement of the mass member 63 due to the vertical force is the moving speed at the initial stage of the movement after that. Less than the moving speed. That is, the ratio of the movement amount of the connecting member 62 in the spool movement direction is smaller than the movement amount of the mass member 63 from the fully open position of the spool 42, and the ratio of both increases as the spool 42 approaches the fully closed position. .

  This characteristic is shown by a broken line in FIG. 14 as the relationship between the elapsed time and the spool displacement. As described above, the spool displacement may be considered to be equivalent to the damping force generated by the shock absorber 1. Therefore, in the present embodiment, the damping force when a relatively small vertical force is generated can be reduced, and the time required for increasing the damping force when a large vertical force is generated can be increased. According to this characteristic, when a large vertical force is continuously generated by a continuous road surface projection as shown in FIG. 15, the oil passage cutoff time associated with the spool movement becomes long, and when the second and subsequent projections are overtaken, In addition to avoiding sudden increase in damping force, the damping force can be increased when passing through the continuous protrusions to speed up the convergence of vibration. That is, if such a damping force characteristic is used, it is possible to achieve both riding comfort and vibration convergence of a vehicle traveling on an irregular road or a rough road.

  FIG. 16 shows a third embodiment corresponding to the second embodiment. In this embodiment, two connecting members 72 are connected to the crank portion 61 side of the second rod 46 so as to be positioned on the front and back of the crank portion 61, and these connecting members 72 are connected to the spool 42 and the crank portion. The crank portion 61 is located at a position deviated from a straight line connecting the rotation center of the 61, specifically on a straight line passing through the rotation center of the crank portion 61 and orthogonal to the straight line connecting the spool 42 and the rotation center of the crank portion 61. Connect to The two connecting members 72 are connected to the crank portion 61 at symmetrical positions with respect to the rotation center of the crank portion 61. Further, a pin 74 is used as a connecting point with the crank portion 61, and the pin 74 is inserted into a long hole 72 a formed in each connecting member 72, thereby connecting the crank portion 61 and each connecting member 72. To do. When the pin 74 is in the fully closed position of the spool 42 (the oil passage communication position in FIG. 16B), the pin 74 abuts against the side surface of the elongated hole 72a on the side where the spool operation portion is disposed.

  Therefore, when the vertical force is applied, as shown in FIG. 16a or 16c, the crank portion 61 rotates as the mass portion 63 moves in the vertical direction of the vehicle, and the second rod moves in conjunction with the rotational motion. 46 is pulled toward the spool operation portion 61 (the connecting member 72 not involved in the interlocking slides the pin 74 within the long hole 72a). As a result, the piston portion 46 b of the second rod 46 comes into contact with the spool operation portion arrangement side surface of the space portion 44 and moves until the spool 42 comes into contact with the spool operation portion arrangement side surface of the spool storage portion 41.

  Accordingly, as in the second embodiment, as shown in FIGS. 4 and 6, the communication between the oil passage 43 and the bypass passages 34, 35, and 36 is blocked, and the first liquid chamber 10 of the cylinder 4 is blocked. The second fluid chamber 11 and the reservoir chamber 7 are disconnected from each other, and when the shock absorber is expanded or contracted, the damping force generating portion of the piston valve 5 and the base valve 8 are operated to generate a damping force in the shock absorber. To do.

  On the other hand, when the vertical force does not act on the vehicle, the spool 42 comes into contact with the spring arrangement side surface of the spool storage portion 41 by the biasing force of the spring 32 as shown in FIG. Accordingly, as in the second embodiment, as shown in FIGS. 3 and 5, the oil passage 43 and the bypass passages 34, 35, and 36 are in communication with each other, and the first liquid chamber 10 of the cylinder 4 is connected. The second fluid chamber 11 and the reservoir chamber 7 communicate with each other through the bypass passages 34, 35, and 36, and a damping force is generated when the shock absorber 1 is contracted. The damping force of the shock absorber 1 generated at this time is This is smaller than the damping force generated in the shock absorber 1 when the vertical force is applied.

  In the present embodiment, when the spool 42 is in the fully open position (oil passage communication position shown in FIG. 16B), the connection point between the connection member 62 and the crank portion 61 is the rotation center of the spool 42 and the crank portion 61. Therefore, the moving speed in the valve closing direction from the fully open position of the spool 42 due to the movement of the mass member 63 by the vertical force is the moving speed at the initial stage of the movement, and the moving speed after that. Bigger than. That is, the ratio of the movement amount of the connecting member 72 in the spool movement direction is larger than the movement amount of the mass member 63 from the fully open position of the spool 42, and the ratio of both decreases as the spool 42 approaches the fully closed position. .

  This characteristic is shown by the solid line in FIG. 14 as the relationship between the elapsed time and the spool displacement. As described above, the spool displacement may be considered to be equivalent to the damping force generated by the shock absorber 1. Therefore, in this embodiment, the damping force when a relatively small vertical force is generated can be increased, and the time required for increasing the damping force when a large vertical force is generated can be shortened. According to this characteristic, it is possible to increase the damping force with respect to the transient road surface input of the vehicle traveling on the good road, and to accelerate the convergence of the vibration.

In the description of the above-described embodiment, the mass member 53 constitutes the mass member of the present invention, and similarly, the bypass passages 34, 35, and 36 constitute flow paths, and the spool 42 serves as the on-off valve and the spool valve. The spool operating unit 50 and the second rod 46 constitute a coupling mechanism.
In each of the above embodiments, the on-off valve is constituted by a spool (valve), but a rotary valve can be used instead.

It is sectional drawing which shows 1st Embodiment of the shock absorber for vehicles of this invention. It is a front view which shows the structure of the shock absorber of FIG. It is a figure which shows the structure of the damping force control part of the shock absorber of FIG. 1, and is a figure which shows the state which the oil path and each bypass path connected. It is a figure which shows the structure of the damping force control part of the shock absorber of FIG. 1, and is a figure which shows the state which the communication state of the oil path and each bypass path interrupted | blocked. FIG. 4 is a detailed view of a state in which the oil passage of FIG. 3 and each bypass passage communicate with each other. It is detail drawing of the state which the communication state of the oil path and each bypass path of FIG. 4 interrupted | blocked. It is a figure which shows the structure of the damping force control part of the shock absorber of FIG. 1, and a spool is located in the state which interrupts | blocks the communication state of an oil path and each bypass path, and a 1st link member and a 2nd link member are It is a figure which shows the state fully extended as a link mechanism. It is a figure used for description of the state change of the spool according to the vertical force which acts on a vehicle, and a spool operation part. It is a characteristic view which shows the relationship between a vertical acceleration and the moving speed of a spool. It is a characteristic view which shows the relationship between a spool position and the damping force of a shock absorber. It is a characteristic view which shows the relationship between a vertical acceleration and damping force ratio. It is a damping characteristic figure at the time of overcoming a temporary road surface protrusion with the shock absorber of FIG. It is a figure which shows 2nd Embodiment of the shock absorber for vehicles of this invention, and is a figure used for description of the state change of the spool according to the vertical force which acts on a vehicle, and a spool operation part. It is a characteristic view which shows the relationship between the elapsed time after a vertical force input, and spool displacement. It is explanatory drawing in case a big vertical force is continuously generated by the continuous road surface protrusion. It is a figure which shows 2nd Embodiment of the shock absorber for vehicles of this invention, and is a figure used for description of the state change of the spool according to the vertical force which acts on a vehicle, and a spool operation part.

Explanation of symbols

1 is a shock absorber 2 is an inner cylinder 3 is an outer cylinder 4 is a cylinder 5 is a piston valve 6 is a piston rod 7 is a reservoir chamber 8 is a base valve 10, 11 is a liquid chamber 30 is a damping force control unit 32 is a spring 33 is a damper 34, 35, 36 are bypass passages 40 are on and bypass passage communication on and off portions 42 are spools 45, 46 are rods 46 a, piston portions 50 are spool operation portions 51, 52 are link members 53, 63 are mass members 62, 72 are Connecting member

Claims (8)

  A piston rod connected to the vehicle body side member, a cylinder connected to the wheel side member and made up of an inner cylinder and an outer cylinder, and the inner cylinder is internally provided to partition the inner cylinder into a first chamber and a second chamber. And a piston chamber connected to the piston rod inserted from one end side of the cylinder, the second chamber formed on the other end side of the cylinder, and a reservoir chamber provided in a gap between the inner cylinder and the outer cylinder A shock absorber for a vehicle, comprising: a first valve for flowing hydraulic fluid between the first chamber; and a second valve provided in the piston for flowing hydraulic fluid between the first chamber and the second chamber. A mass member that is moved by vertical force generated in the vehicle, a first channel that communicates the first chamber and the second chamber, a second channel that communicates the second chamber and the reservoir chamber, Opening and closing to open and close the first channel and the second channel When the connecting opening and closing valve and a mass member, a vehicle shock absorber, characterized in that a connecting mechanism for switching the opening and closing state of the on-off valve in conjunction with the movement of the mass member by the vertical force.   The on-off valve is a spool valve, a spring that applies an urging force to the spool valve so as to move to a position in which the spool valve is opened, and the spring is attached to the spring, and the spool valve is moved when the spool valve moves. The vehicle shock absorber according to claim 1, further comprising an attenuator that applies a damping force to the valve.   The vehicle shock absorber according to claim 2, wherein the coupling mechanism is coupled to the spool valve with a coupling rod with play in a moving direction of the spool valve.   A space that is formed in the spool valve and is long in the moving direction of the spool valve, and an opening that is in communication with the space and is formed at the end of the spool valve and is smaller than the inner diameter of the space, The connecting rod is provided with a locking portion that is formed at one end inserted through the opening into the space and has a convex shape in the radial direction, and the connecting mechanism is interlocked with the movement of the mass member by the vertical force. By moving the connecting rod in the moving direction of the spool valve, the locking portion is locked to the end surface on the space portion side of the opening, and the spool valve is moved to a position where the spool valve is closed. The shock absorber for a vehicle according to claim 3, wherein the shock absorber is for a vehicle.   The connection mechanism according to any one of claims 1 to 4, wherein when the spool valve is moved from the open state to the closed state, a moving speed at an initial stage of movement of the spool valve is made lower than a moving speed thereafter. The vehicle shock absorber according to claim 1.   The connection mechanism has a rotation mechanism that rotates as the mass member moves due to the vertical force, and a straight line that connects the spool valve and the rotation center of the rotation mechanism when the spool valve is in an open state. 6. The vehicle shock absorber according to claim 5, wherein the rotating mechanism and the connecting rod are connected at a position above or in the vicinity thereof, and the connecting rod is connected to a spool valve.   The connection mechanism according to any one of claims 1 to 4, wherein when the spool valve is moved from the open state to the closed state, the moving speed at the initial stage of movement is larger than the moving speed thereafter. The vehicle shock absorber according to claim 1.   The connection mechanism has a rotation mechanism that rotates as the mass member moves due to the vertical force, and a straight line that connects the spool valve and the rotation center of the rotation mechanism when the spool valve is in an open state. The vehicle shock absorber according to claim 7, wherein the rotating mechanism and the connecting rod are connected at a position deviated from the connecting rod, and the connecting rod is connected to the spool valve.

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