JP2006052831A - Shock absorber for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorber for a vehicle capable of controlling a damping force by a simple structure. <P>SOLUTION: This shock absorber 1 comprises a mass member 53 moved by a lateral acceleration produced in the vehicle, bypass passages 34, 35, and 36 allowing the first liquid chamber, the second liquid chamber, and the reservoir chamber of an unshown cylinder to communicate with each other, a spool 42 opening/closing the bypass passages 34, 35, and 36, and a spool operation part 50 as a connection mechanism connecting the spool 42 to the mass member 53 and bringing the spool 42 from a valve opened state to a valve closed state in association with the movement of the mass member 53 by the lateral acceleration of the vehicle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle shock absorber used in a vehicle suspension.

  As a conventional vehicle shock absorber, there is one disclosed in Patent Document 1. As shown in FIG. 24, a vehicle shock absorber 201 disclosed in Patent Document 1 includes a cylinder 204 including an inner cylinder 202 and an outer cylinder 203, a piston 205 inserted into the inner cylinder 202, and a lower end on the piston 205. Are connected to each other and a hollow piston rod 206 extending up and down in the inner cylinder 202 and a resonance part 207 attached to the upper end of the piston rod 206 are provided.

The cylinder 204 is provided with a base valve 208 at the bottom of the inner cylinder 202, and a lower end eyeball 209 is attached to a wheel side (not shown), and the inner cylinder 202 is filled with hydraulic oil. . For example, the piston 205 is provided with a damping force generator 210 having the same structure as the damping force generator in the shock absorber disclosed in Patent Document 2.
The resonating unit 207 is fixed to the upper end of the piston rod 206 and is filled with hydraulic oil inside the case 211, a movable mass body (movable mass) 212 disposed in the case 211, and above and below the movable mass body 212. A spring 213 that is installed and elastically floats and supports the movable mass body 212 in the vertical direction, and is integrally provided on the lower surface of the movable mass body 212 so as to extend substantially downward in the hollow portion of the piston rod 206. And a control unit 214 that reaches the generation unit 210.

In the resonance unit 207, the substantially vertical resonance frequency of the movable mass body 212 supported in the vertical direction by the upper and lower springs 213 is set to be close to the upper sprung mass body of the suspension, that is, the vertical resonance frequency in the vehicle body. Yes.
A plurality of oil passages (not shown) are formed symmetrically on the inner peripheral surface of the case 211 at regular intervals, and the upper chamber 216 and the lower chamber 217 of the case 211 communicate with each other through these oil passages. The top portion of the case 211 is attached to the vehicle body side 220 via an insulator rubber 219. The movable mass body 212 is slidable in the vertical direction within the case 211.

In the conventional shock absorber 201 having such a configuration, (1) when the vehicle body is stationary in the vertical direction (non-resonant), the vehicle body descending direction (shrinking direction of the shock absorber 201), and the vehicle body In any of the upward directions (extension direction of the shock absorber 201), the damping force of the damping force generation unit 210 with respect to the vertical vibration of the vehicle body is kept the smallest by the control unit 214. (2) When the vehicle body is lowered, the control unit 214 Is deeply inserted into the damping force generation unit 210, so that the damping force of the damping force generation unit 210 with respect to the downward displacement of the vehicle body is maximized by the control unit 214 in the downward direction of the vehicle body (the contraction direction of the shock absorber 201). On the other hand, in the ascending direction of the vehicle body (the direction in which the shock absorber 1 extends), the damping force generator 210 attenuates against the upward displacement of the vehicle body. Is kept relatively small by the control unit 214. (3) When the vehicle body is lifted, the control unit 214 is shallowly inserted into the damping force generation unit 210. As a result, the vehicle body ascending direction (extension of the shock absorber 201) Direction), the damping force of the damping force generation unit 210 with respect to the upward displacement of the vehicle body is maximized by the control unit 214, while the damping force generation with respect to the downward displacement of the vehicle body in the downward direction of the vehicle body (the contraction direction of the shock absorber 201). The damping force of the unit 210 is kept relatively small by the control unit 214.
JP 2002-5219 A JP-A-10-318321

By the way, there is a case where it is desired to control the damping force again even after the wheel gets over the protrusion on the traveling path. For example, immediately after a wheel gets over a protrusion, vibration remains in the vehicle body due to the wheel getting over the protrusion, but you want to suppress the vibration of the vehicle body by controlling the damping force of the shock absorber There is.
Here, in the conventional shock absorber 201, the damping force changes in conjunction with the vertical movement of the vehicle body, so that the damping force changes when the wheel gets over the protrusion on the travel path. However, since the conventional shock absorber 201 does not adjust the damping force immediately after the wheel gets over the protrusion, vibration remains in the vehicle body.

Further, in the conventional shock absorber 201, it is considered that the movable mass body 212 constantly vibrates due to its support structure even when the vehicle is traveling on a flat road (especially a road surface on which small unevenness is repeated). However, it is considered that abnormal noise is generated due to the movement of the movable mass 212 when it constantly vibrates.
Furthermore, since the conventional shock absorber 201 has a structure that focuses on sprung vibration (for example, vibration of 1 to 1.5 kHz), the damping force is controlled for a roll generated by lateral acceleration during turning. I couldn't.

The present invention has been made in view of the above problems, and an object thereof is to provide a vehicle shock absorber having a simple structure and capable of controlling the damping force even immediately after a wheel gets over a protrusion.
Another object of the present invention is to provide a vehicle shock absorber that can control a damping force with respect to a roll generated by lateral acceleration during turning.

  The shock absorber for a vehicle according to claim 1 is a piston rod connected to a vehicle body side member, a cylinder connected to a wheel side member, and comprising an inner cylinder and an outer cylinder, and the inner cylinder in a first chamber and a second chamber. A piston internally connected to the inner cylinder so as to be partitioned and connected to a piston rod inserted from one end of the cylinder; a reservoir chamber communicating with the second chamber; and a second chamber and a reservoir chamber A shock absorber for a vehicle comprising a first valve for flowing hydraulic fluid between the first valve and a second valve provided in the piston for flowing hydraulic fluid between the first chamber and the second chamber. .

  The vehicle shock absorber includes a mass member that moves due to acceleration generated in the vehicle, a first channel that communicates the first chamber and the second chamber, and a second channel that communicates the second chamber and the reservoir chamber. An open / close valve that opens and closes the first flow path and the second flow path, connects the open / close valve and the mass member by a connection mechanism, and opens and closes the open / close valve in conjunction with the movement of the mass member by the acceleration. Switch the state.

  For example, the vehicle shock absorber according to claim 5 is configured such that when the vehicle is not laterally accelerated, the opening / closing valve is opened so that the gap between the first chamber, the second chamber, the inner cylinder, and the outer cylinder is reduced. Becomes a communication state, and the damping force becomes small. On the other hand, when lateral acceleration occurs in the vehicle, the open / close 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 cut off. Thus, the damping force increases. In this way, the control of the damping force of the vehicle shock absorber is a lateral acceleration sensitive control.

  In the vehicle shock absorber according to claim 6, the mass member is moved by causing vertical acceleration greater than a predetermined threshold to occur in the vehicle when the wheel gets over the protrusion on the traveling path, and While the on-off valve is over the projection on the road, the area of at least one of the first and second channels is the same as when the wheel is running on a flat road. Immediately after the wheel gets over the protrusion on the travel path, the flow path with the changed area is closed.

  As a result, when the wheel is over the projection on the road and the vehicle is accelerated in the vertical direction greater than a predetermined threshold, the first and second flow paths are in the middle of the wheel over the projection on the road. By making the area of at least one of the flow paths larger than that when the wheels are traveling on a flat road, the damping force of the vehicle shock absorber is reduced, and the wheels get over the protrusions on the traveling road Immediately after that, by closing the flow path whose area has been changed, the damping force of the shock absorber for the vehicle is in the middle when the wheel is over the projection on the road and the case where the wheel is running on the flat road. It is bigger than the ones.

According to the present invention, the damping force of the vehicle shock absorber can be controlled in accordance with the lateral acceleration with a simple configuration such as a mass member, a flow path, an on-off valve such as a spool valve, and a coupling mechanism.
That is, in the invention of claim 5, the vehicle shock absorber has a small damping force when the vehicle is not laterally accelerated, and can increase the damping force when the vehicle is laterally accelerated. . As a result, it is possible to improve the vehicle stability by attenuating the rolls and the like when the vehicle is turning without impairing the riding comfort performance when traveling straight ahead.

  In the invention according to claim 6, the shock absorber for the vehicle has a small damping force while the wheel gets over the protrusion on the road, and the damping force becomes large immediately after the wheel gets over the protrusion on the road. The damping force can be optimally controlled with respect to the wheels getting over the protrusions on the road.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.
The first embodiment is a shock absorber for a vehicle suspension to which the present invention is applied. 1 and 2 show the configuration of the shock absorber 1. FIG. 1 is a view of the upright shock absorber 1 as seen from the vehicle longitudinal direction, and FIG. 2 is a view of the upright shock absorber 1 as seen from the vehicle width direction.

The shock absorber 1 includes a cylinder 4 having an inner cylinder 2 and an outer cylinder 3, a piston valve 5 that is slidably inserted into the inner cylinder 2 in the axial direction thereof, and a lower end connected to the piston valve 5. A piston rod 6 extending substantially vertically in the cylinder 2 and a damping force control unit 30 for controlling the damping force in the shock absorber 1 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 attached 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 these flows.
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 will be described later. It communicates with the control unit 30.
The upper end of the piston rod 6 is attached 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 above (the direction of arrows AA in FIGS. 1 and 2).
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 a cylindrical spool storage portion 41 formed to extend in the vehicle front-rear direction, and a substantially cylindrical spool (spool valve) 42 stored in the spool storage portion 41. And.

  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, the second bypass path 35 is connected to the second liquid chamber 11, and the third bypass path 36 is connected to the reservoir chamber 7. Yes. In the first 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 aligned in the vehicle front-rear direction, and the second bypass path 35 is connected to the spool storage portion 41. The first bypass passage 34 and the third bypass passage 36 are connected to a portion on the opposite side to the portion to which the first bypass passage 34 and the third bypass passage 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. Further, the spool storage portion 41 and the first to third bypass passages 34, 35, 36 are filled with hydraulic oil, like the first and second liquid chambers 10, 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 includes a portion 43a having one end communicating with the first bypass passage 34, a portion 43b having one end communicating with the second bypass passage 35, and a portion 43c having one end communicating with the first bypass passage 36. It is composed of

As shown in FIG. 3, one end surface of the spool 42 abuts against 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 this case, as clearly shown in FIG. 5, the oil passage 43 communicates with each bypass passage 34, 35, 36 connected to the spool storage portion 41.
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 (to be 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 cut off.

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 and 36 are designed to be in a communication state or in a state in which the communication is cut off.
Further, the spool 42 has a first rod 45 formed on the end surface on the side where the oil passage 43 is formed, extending 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 end portions of the first and second rods 45 and 46 are inserted into the spool storage portion 41 from both side surfaces of the spool storage portion 41 in the vehicle front-rear direction and attached to the spool 42.

At the other end of the first rod 45, a spring 32 and an attenuator 33 are attached to the spring 32. 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 hollow portion 44 formed inside the spool 42 near the other end. The hollow portion 44 has a cylindrical shape extending in the moving direction of the spool 42 and is opened at the end surface of the spool 42.

  The second rod 46 has a body portion 46a inserted through the opening of the end surface of the spool 42 into the hollow portion 44, and a piston portion 46a is integrally formed at the end of the inserted body portion 46a. ing. Here, the piston portion 46 a is movable in the vehicle front-rear direction within the empty portion 44. In the second rod 46, the other end of the main body 46 a 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 link members 51 and 52. That is, the first link member 51 and the second link member 52 are connected to each other so as to be rotatable at one end, and the other end of the first link member 51 is connected to the other end of the main body 46a of the second rod 46. 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.
Note that, although not shown, the connecting portion between the first link member 51 and the second rod 46 is constrained so as to move only in the vehicle front-rear direction, for example, by a constraining member.

  The spool operating unit 50 configured as described above allows the mass member 53 to move in the vehicle width direction by the link structure 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 width 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. As a result, the piston portion 46 b of the second rod 46 moves in the vehicle front-rear direction within the empty portion 44 of the spool 42.

Here, as shown in FIG. 3, the end surface of the piston portion 46 a is in the front and rear of the empty portion 44 in a state where the first link member 51 and the second link member 52 of the spool operation portion 50 are fully extended as a link mechanism. The spring 32 and the attenuator 33 in the direction are arranged so as not to come into contact with the side surface (hereinafter referred to as the spring arrangement side empty side surface). That is, as shown in FIG. 7, the first link member 51 and the second link member 52 extend 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 vehicle 44 in the longitudinal direction of the vehicle or the length of the second rod 46 is determined so that the piston portion 46a does not come into contact with the side surface of the spring arrangement side of the empty portion 44 even when it is in a closed state. Has been.
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.
(1) During turning traveling and straight traveling FIG. 8 shows the configuration of the damping force control unit 30, particularly the configuration of the spool 42 and the spool operating unit 50. In FIG. 8, it is assumed that the upper side is the left side of the vehicle and the lower side is the right side of the vehicle. FIG. 9 shows the traveling state of the vehicle.

(1-1) When Turning Right or When Turning Left As shown in FIG. 9A, when the vehicle 100 turns right, lateral acceleration in the right direction is generated in the vehicle, and accordingly, the mass member 53 The external force in the left direction (the direction indicated by the arrow P in FIG. 9) is applied to As a result, as shown in FIG. 8A, the first link member 51 and the second link member 52 of the spool operating portion 50 are bent, and the second rod 46 is pulled toward the spool operating portion 50 side. It is done. Accordingly, the outer peripheral portion (convex shape portion) of the piston portion 46b of the second rod 46 is referred to as a side surface on the arrangement side of the spool operation portion 50 in the vehicle longitudinal direction of the empty portion 44 (hereinafter referred to as a spool operation portion arrangement side empty portion side surface). In other words, the second rod 46 is in contact with the outer peripheral portion 54 of the opening of the spool 42 through which the second rod 46 is inserted, and the spool 42 is moved until it comes into contact with the spool operating portion arrangement side surface of the spool storage portion 41. 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, communication with the oil path 43 and each bypass path 34,35,36 is interrupted | blocked.

  The same operation is performed even if the vehicle turns left. That is, when the vehicle turns left, lateral acceleration in the left direction is generated in the vehicle, and thereby, an external force in the right direction 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. It is done. As a result, the piston portion 46b of the second rod 46 contacts the spool operation portion arrangement side side surface of the empty portion 44 of the spool 42 and moves until the spool 42 contacts the spool operation portion arrangement side surface of the spool storage portion 41. To do. Thereby, as shown in the said FIG.4 and FIG.6, communication with the oil path 43 and each bypass path 34,35,36 is interrupted | blocked.

As a result, the first liquid chamber 10, the second liquid chamber 11, and the reservoir chamber 7 of the cylinder 4 are blocked by the bypass passages 34, 35, and 36. As a result, when the shock absorber 1 is expanded and contracted, the damping force generating portion of the piston valve 5 and the base valve 7 are operated 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.

When the shock absorber 1 extends, that is, when the piston rod 6 or the piston valve 5 moves upward, the pressure in the first liquid chamber 10 and the pressure in the second liquid chamber 11 are mainly used. Due to the pressure difference, a damping force is generated in the shock absorber 1 due to the hydraulic fluid flowing from the first fluid chamber 10 to the second fluid chamber 11 via the damping force generating portion of the piston valve 5.
Further, the damping force caused by the hydraulic fluid flowing from the second liquid chamber 11 to the reservoir chamber 7 via the base valve 7 due to the pressure difference between the pressure in the second liquid chamber 11 and the pressure in the reservoir chamber 7 is shocked. Occurs in the absorber 1.

(1-2) Straight Traveling When the vehicle travels straight as shown in FIG. 9B, external force in the vehicle width direction does not act on the mass member 53. Therefore, as shown in FIG. The first link member 51 and the second link member 52 of the operation unit 50 are fully extended as a link mechanism. At this time, the spool 42 is in contact with the side surface on the spring arrangement side of the spool storage portion 41 by the biasing force of the spring 32. Thereby, as shown in the said FIG.3 and FIG.5, the oil path 43 and each bypass path 34,35,36 will be in the state connected.

As a result, the first liquid chamber 10, the second liquid chamber 11, and the reservoir chamber 7 of the cylinder 4 are in communication with each other through the bypass passages 34, 35, and 36. As a result, a damping force is generated in the shock absorber 1 during expansion and contraction.
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 35, the oil path 43 of the spool 42 of the damping force control unit 30, and The hydraulic oil in the second liquid chamber 11 flows into the first liquid chamber 10 via the first bypass path 34.

When the shock absorber 1 extends, that is, when the piston rod 6 or the piston valve 5 moves upward, the first bypass path 34, the oil path 43 of the spool 42 of the damping force control unit 30, and the second bypass The hydraulic oil in the first liquid chamber 10 flows into the second liquid chamber 11 through the path 35.
Due to such a flow, a damping force is generated in the shock absorber 1. However, the damping force is smaller than the damping force generated in the shock absorber 1 during the right turn traveling or the left turn traveling. As described above, the control of the damping force of the shock absorber 1 is a lateral acceleration-sensitive control, and the damping force during turning travel is larger than the damping force during straight traveling.

(2) Other Characteristics (2-1) Various Characteristics FIG. 10 shows the damping force of the shock absorber 1 during turning and straight traveling, using the speed of the piston valve 5 as a parameter. As shown in FIG. 10, the damping force of the shock absorber 1 is larger when turning while turning than when traveling straight. 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. 11 shows the relationship between the lateral acceleration and the moving speed of the spool 42 in the spool storage unit 41. As shown in FIG. 11, the moving speed of the spool 42 in the spool storage portion 41 increases as the lateral acceleration increases. As a result, for example, when the lateral acceleration is large due to sudden turning or the like, the moving speed of the spool 42 increases, and as a result, the damping force of the shock absorber 1 increases with an early rise. Further, when the lateral acceleration is small due to, for example, additional cutting, the moving speed of the spool 42 becomes slow, and as a result, the damping force of the shock absorber 1 gradually increases.

FIG. 12 shows the relationship between the position of the spool 42 in the spool storage 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 interrupted. 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. 12, 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. Tends to flow into the oil passage 43 or the hydraulic oil easily flows out from 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), whereby the hydraulic oil flows into the oil passage 43. It becomes difficult or it becomes difficult for hydraulic oil to flow out from 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.

(2-2) Characteristics of damping force of shock absorber 1 when traveling on continuous curve As shown in FIG. 13A, damping force of shock absorber 1 when vehicle 100 is traveling on a continuous curve. The characteristics of will be described.
When the vehicle 100 is traveling on a continuous curve, as shown in FIG. 13B, lateral acceleration is generated in the vehicle 100 according to the vehicle behavior. At this time, an external force in the direction opposite to the turning direction (the direction indicated by the arrow P in FIG. 13A) acts on the mass member 53 of the damping force control unit 30.

  As described above, the second rod 46 is attached to the spool 42 with so-called play in the vehicle longitudinal direction. As a result, as shown in FIG. 7, the first link member 51 and the second link member 52 are connected to each other in the state where the other end surface of the spool 42 is in contact with the side surface on the spool operation portion arrangement side of the spool storage portion 41. Even in the fully extended state, the piston portion 46a does not hit the side surface of the empty portion 44 on the spring arrangement side.

  For this reason, when the vehicle 100 turns, in a state where the spool 42 is in contact with the side surface on the spool operation portion arrangement side of the spool storage portion 41 as shown in FIG. Since the vehicle has shifted to straight traveling, the external force in the vehicle width direction does not act on the mass member 53, and the first link member 51 and the second link member 52 of the spool operation unit 50 as shown in FIG. 8B. The second rod 46 moves in the vehicle front-rear direction ahead of the spool 42, and the piston portion 46a of the second rod 46 is substantially within the empty portion 44. Located in the central part. As a result, 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 the movement starts to the side, that is, for example, when the vehicle starts to turn again, the piston portion 46b of the second rod 46 abuts against the side surface of the empty portion 44 on the side of the spool operating portion arrangement side. From the middle of the movement, it moves in the opposite direction. That is, with reference to FIG. 12, when the vehicle starts turning again from straight running, the opening of the orifice changes again in the fully closed direction before it is fully opened. The damping force of 1 turns from increasing to decreasing before reaching the minimum value.

As described above, the second rod 46 is attached to the spool 42 with so-called play in the longitudinal direction of the vehicle, so that even when the vehicle 100 is traveling on a continuous curve, it is shown as a solid line in FIG. In addition, the damping force of the shock absorber 1 fluctuates in the vicinity of a large predetermined value without reaching a minimum value.
In other words, assuming that the second rod 46 is directly attached to the spool 42 without causing so-called play in the vehicle front-rear direction, the spool 42 always moves in conjunction with the movement of the mass member 53. . In this case, as indicated by the alternate long and short dash line in FIG. 13C, the damping force of the shock absorber 1 fluctuates between a minimum value and a maximum value corresponding to switching between turning and straight traveling of the vehicle. It becomes like this.
As shown by a dotted line in FIG. 13C, in the case of a shock absorber that does not include the damping force control unit 30, that is, a conventional shock absorber, the damping force is constant regardless of the presence or absence of turning.

(2-3) Characteristics of damping force of shock absorber 1 when switching from straight traveling to turning traveling The vehicle travel state changes from straight traveling (for example, the traveling state of FIG. 9B) to turning traveling (for example, FIG. 9A). The operation of the shock absorber 1 when switching to (traveling state) will be described.
When the vehicle is traveling straight, an external force in the vehicle width direction does not act on the mass member 53, so that the piston portion 46a is positioned, for example, at the center in the empty portion 44 as shown in FIG. When the vehicle starts to turn from such a state, the piston portion 46 b of the second rod 46 starts moving in the empty portion 44. Then, the piston portion 46b comes into contact with the side surface of the empty portion 44 on the side of the spool operation portion arrangement side, so that the spool 42 moves together with the second rod 46 to the arrangement side of the spool operation portion 50 in the vehicle front-rear direction. become.

  Thus, when the vehicle traveling state is switched from straight traveling to turning, even if a lateral acceleration occurs in the vehicle, that is, even if an external force in the vehicle width direction acts on the mass member 53, the spool 42 does not move immediately. is there. That is, the relationship between the lateral acceleration and the damping force ratio of the shock absorber 1 will be described with reference to FIG. 14. Even if the vehicle traveling state is switched from straight traveling to turning traveling and lateral acceleration begins to occur in the vehicle, the rising delay With the (dead zone), the damping force ratio of the shock absorber 1 increases. Here, the damping force ratio of the shock absorber 1 is a value obtained by dividing the damping force of the shock absorber 1 generated by the movement of the spool 42 as a result of the occurrence of lateral acceleration by the damping force of the shock absorber 1 during straight traveling. It is.

Next, effects of the first embodiment will be described.
As described above, the shock absorber 1 has a damping force by the bypass passages 34, 35, and 36, the bypass passage communication ON / OFF portion 40 including the spool 42, and the spool operation portion 50 configured as a connecting rod mechanism. Control is performed. Thereby, the shock absorber 1 realizes damping force control with a simple configuration. As a result, since there is no need to provide a resonance portion between the piston rod and the vehicle body as in the conventional case, the degree of freedom in the design of the vehicle body, for example, the shape of the engine room, can be increased, and the suspension stroke can also be increased. it can. That is, for example, the shock absorber 1 can be attached to the vehicle without affecting the component characteristics (hood height, upper mount characteristics, bumper rubber characteristics, etc.) around the upper mount.

Further, as described above, the shock absorber 1 has a small damping force when no lateral acceleration is generated in the vehicle, and has a large damping force when no lateral acceleration is generated in the vehicle. Accordingly, the vehicle stability can be improved by attenuating the roll or the like when turning the vehicle without impairing the riding comfort performance when traveling straight ahead.
Further, 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. As a result, 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.

  Further, as described above, the second rod 46 is attached to the spool 42 with a so-called play in the vehicle longitudinal direction. Thus, even if the mass member 53 moves due to the lateral 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 two-liquid chamber 11 and the reservoir chamber 7 does not frequently switch, that is, the damping force of the shock absorber 1 does not frequently switch.

  In particular, when the running state of the vehicle switches from turning to straight running, 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. To come. As a result, as described above, even when the vehicle is traveling on a continuous curve, the damping force of the shock absorber 1 does not reach the minimum value, but fluctuates in the vicinity of the large predetermined value.

The first embodiment of the present invention has been described above. However, the present invention is not limited to being realized as the first embodiment.
That is, in the first embodiment, the case where the spool operating portion 50 that operates the spool 41 or the second rod 46 is configured as a so-called connecting rod mechanism including the rod-shaped first and second link members 51 and 52 has been described. However, it is not limited to this.

  For example, as shown in FIG. 15, the spool operation unit 60 includes a crank part 61, a connecting member 62 that connects the crank part 61 and the second rod 46, and a mass member 63 provided on the crank part 61. . Here, the crank part 61 is rotatably supported by a non-moving part of the damping force control part 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 mass member 63 moves in the vehicle width direction, the spool operation unit 60 configured in this way rotates the crank portion 61, and the rotation 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, the shock absorber 1 operates as follows during right turn traveling or left turn traveling.

  When turning right or turning left, as shown in FIG. 15 (a) or 15 (c), an external force acts on the mass member 63 in the vehicle width direction, and the crank portion 61 rotates and interlocks with the rotation. Then, the second rod 46 is pulled toward the spool operation unit 60 side. As a result, the piston portion 46 b of the second rod 46 comes into contact with the spool operation portion arrangement side side surface of the empty portion 44, and the spool 42 moves until it comes into contact with the spool operation portion arrangement side surface of the spool storage portion 41.

  As a result, as in the first embodiment, as shown in FIGS. 4 and 6, the communication between the oil passage 43 and the bypass passages 34, 35, and 36 is cut off. As a result, the first liquid chamber 10, the second liquid chamber 11, and the reservoir chamber 7 of the cylinder 4 are blocked by the bypass passages 34, 35, and 36. As a result, when the shock absorber 1 is expanded and contracted, the damping force generating portion of the piston valve 5 and the base valve 7 are operated to generate a damping force in the shock absorber 1.

  On the other hand, during straight traveling, as shown in FIG. 15B, external force in the vehicle width direction does not act on the mass member 63, and as a result, the spool 42 is a spring of the spool housing portion 41 by the urging force of the spring 32. It will be in the state contact | abutted to the arrangement side surface. As a result, as in the above-described 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. As a result, the first liquid chamber 10, the second liquid chamber 11, and the reservoir chamber 7 of the cylinder 4 are in communication with each other through the bypass passages 34, 35, and 36. As a result, a damping force is generated in the shock absorber 1 during expansion and contraction. The damping force of the shock absorber 1 generated at this time is smaller than the damping force generated in the shock absorber 1 during the right turn traveling or the left turn traveling.

  In addition, as shown in FIG. 16, in the bypass passage communication ON / OFF portion 40, switching of the communication state between the oil passage 43 and each bypass passage 34, 35, 36 is replaced with a spool (spool valve) 42 and a rotary valve. 47. For example, an oil passage having a predetermined shape is formed on the outer peripheral surface of the rotary valve 47, and the communication state between the oil passage and each bypass passage 34, 35, 36 is switched by the rotation of the rotary valve 47. . Corresponding to such a configuration, a rotary valve operating unit 70 that rotates the rotary valve 47 is provided.

The rotary valve operation unit 70 is configured as a link mechanism that forms a so-called pendulum structure by the mass member 71 and a connecting member 72 that connects the mass member 71 and the outer peripheral surface of the rotary valve 47. The mass member 71 is provided with a spring 73 that applies a biasing force to the mass member 71, that is, the rotary valve 47 so that the mass member 71 is at a predetermined position, in this case, the lowest position during straight traveling. One end of the spring 73 is attached to the mass member 71, and the other end is fixed to a stationary part of the damping force control unit 30, for example, the case 31.
With this configuration, the shock absorber 1 operates as follows during right turn traveling or left turn traveling.

  During right turn traveling or left turn traveling, as shown by a dotted line in FIG. 16, when an external force acts on the mass member 71 in the vehicle width direction, the rotary valve 47 rotates together with the mass member 71. Thereby, the communication between the oil passage and each bypass passage 34, 35, 36 is cut off. As a result, the first liquid chamber 10, the second liquid chamber 11, and the reservoir chamber 7 of the cylinder 4 are blocked by the bypass passages 34, 35, and 36. As a result, when the shock absorber 1 is expanded and contracted, the damping force generating portion of the piston valve 5 and the base valve 7 are operated to generate a damping force in the shock absorber 1.

  On the other hand, as shown by a solid line in FIG. 16, when the vehicle travels straight, the mass member 71 is not subjected to an external force in the vehicle width direction, and the urging force of the spring 73 causes the rotary valve 47 to be in a predetermined position in the rotational direction. An oil path and each bypass path 34,35,36 will be in the state connected. As a result, the first liquid chamber 10, the second liquid chamber 11, and the reservoir chamber 7 of the cylinder 4 are in communication with each other through the bypass passages 34, 35, and 36. As a result, a damping force is generated in the shock absorber 1 during expansion and contraction. The damping force of the shock absorber 1 generated at this time is smaller than the damping force generated in the shock absorber 1 during the right turn traveling or the left turn traveling.

  In the description of the first embodiment, the mass member 53 realizes a mass member that moves due to lateral acceleration generated in the vehicle, and the bypass passages 34, 35, and 36 are the first chamber and the second chamber, respectively. And a flow path that communicates a gap (reservoir chamber) between the inner cylinder and the outer cylinder, and a spool (spool valve) 42 realizes an open / close valve that opens and closes the flow path, The second rod 46 connects the open / close valve and the mass member, and realizes a connection mechanism that links the open / close valve from the open state to the closed state in conjunction with the movement of the mass member due to the lateral acceleration.

Next, a second embodiment will be described.
This second embodiment is also a shock absorber for a vehicle suspension to which the present invention is applied. FIG. 17 is a view of the upright shock absorber 1 as seen from the vehicle width direction. In addition, the figure which looked at the shock absorber 1 in this 2nd Embodiment from the vehicle front-back direction is the same as that of the said FIG.
18 and 19 show a detailed configuration of the damping force control unit 30. FIG. The configuration of the damping force control unit 30 shown in FIG. 18 is a configuration seen from the vehicle width direction, and the configuration of the damping force control unit 30 shown in FIG. 19 is seen from the down direction (the direction of arrow BB in FIG. 17). It is a configuration.

  As shown in FIGS. 17 to 19, the damping force control unit 30 includes a spring 32, a damper 33, a bypass communication on / off unit 110, and a spool operation unit 130 in a case 31. As shown in FIGS. 17 to 19, the structure of the shock absorber 1 of the second embodiment is particularly different from that of the shock absorber 1 of the first embodiment in the damping force control unit 30. The bypass passages 104, 105, and 106, the bypass passage communication on / off portion 110, and the spool operation portion 130 are different.

As in the first embodiment, the bypass passage communication on / off portion 110 is housed in a cylindrical spool housing portion 111 formed to extend in the vehicle front-rear direction and the spool housing portion 111. A substantially cylindrical spool (spool valve) 121 is provided.
In the second embodiment, the shape of the bypass passages 104, 105, and 106 and the shape of the oil passage formed in the spool 121 corresponding to the bypass passages 104, 105, and 106 are different as follows. It has become. FIG. 20 shows details of these shapes.

  In the spool storage portion 111, bypass paths (hereinafter referred to as first and second bypass walls in the peripheral wall) 113 and 114 are formed in the peripheral wall (cylinder portion) 112 of the spool storage portion 111, and the spool storage In the section 111, the first bypass passage 104 is connected to the first inner circumferential wall bypass passage 113, and two second and third bypass passages 105 and 106 are connected to the second inner circumferential wall bypass passage 114.

  Here, similarly to the first embodiment, the first bypass passage 104 is connected to the first liquid chamber 10, the second bypass passage 105 is connected to the second liquid chamber 11, and The 3 bypass path 106 is connected to the reservoir chamber 7. The first and second bypass passages 104 and 105 form a flow path mainly for communicating the first liquid chamber 10 and the second liquid chamber 11, and the second and bypass passages 105 and 106 are second. A flow path for communicating the liquid chamber 11 and the reservoir chamber 7 is formed.

  The first peripheral wall bypass passage 113 and the second peripheral wall bypass passage 114 are formed in substantially the same shape at opposite positions on the peripheral wall of the spool housing portion 111. That is, the first bypass wall 113 is branched immediately after the connection portion with the first bypass passage 104, one branch passage extends in the vehicle front-rear direction, and the end of each branch passage is a spool housing portion. 111 communicates. Similarly to the first peripheral wall bypass path 113, the second peripheral wall bypass path 114 also branches immediately after the connection portion with the second and third bypass paths 105 and 106, and one branch path is a vehicle. It extends in the front-rear direction, and the end of each branch passage communicates with the spool storage portion 111.

With such a structure, the spool storage unit 111 includes the first and second bypass inner wall bypass passages 113 and 114 and the first to third bypass passages 104, 105, and 106 formed in the peripheral wall 112 of the spool storage unit 111. The first and second liquid chambers 10 and 11 and the reservoir chamber 7 communicate with each other.
Here, in particular, in the first peripheral wall bypass passage 113 and the second peripheral wall bypass passage 114, a branch passage (particularly a communicating portion with the spool housing portion 111) positioned on the spring 32 and the attenuator 33 side in the vehicle longitudinal direction. 113a and 114a) have different diameters, and the second peripheral wall bypass passage 114 (114a) has a larger diameter. Note that the branch portions (particularly, the communication portions 113b and 114b with the spool storage portion 111) positioned on the spool operation portion 130 side in the vehicle longitudinal direction have the same diameter.

  On the other hand, as shown in FIG. 20, first and second oil passages 122 and 123 are formed in the spool 121. The first oil passage 122 is formed in the spool 121 on the side where the spring 32 and the attenuator 33 are disposed, and the second oil passage 123 is formed in the spool 121 on the spool operation unit 130 side. The first oil passage 122 and the second oil passage 123 have substantially the same shape, that is, the first oil passage 122 is constituted by two flow passages (orifices) 122a and 122b penetrating in the radial direction. The second oil passage 123 is constituted by two flow passages (orifices) 123a and 123b penetrating in the radial direction.

  By setting it as the above bypass path shape and oil path shape, as shown to Fig.20 (a), the spool 121 to the predetermined position (henceforth a spring arrangement | positioning side) of the arrangement | positioning side of the spring 32 and the attenuator 33 is shown. The first bypass passage 104 and the second and third bypass passages 105 and 106 communicate with each other in the first oil passage 122 via the bypass passages 113 and 114 in the peripheral wall of the spool storage portion 111 when the first storage passage 111 moves. become. Further, as shown in FIG. 20C, even when the spool 121 moves to a predetermined position on the arrangement side of the spool operation 130 (hereinafter referred to as the spool operation section arrangement side), the bypass in the peripheral wall of the spool storage section 111 is also achieved. The first bypass passage 104 and the second and third bypass passages 105 and 106 communicate with each other through the passages 113 and 114 in the second oil passage 123.

  Here, as described above, the first oil passage 122 and the second oil passage 123 are formed in substantially the same shape, while the first circumferential wall bypass passage 113 and the second circumferential wall bypass passage 114 are arranged in the vehicle front-rear direction. When the spool 121 moves to the spring arrangement side by making the diameter of the branch path located on the spring 32 and the attenuator 33 side in the direction different and making the second bypass wall 114 in the peripheral wall larger in diameter. On the other hand, the first bypass passage 104 and the second and third bypass passages 105 and 106 are communicated with each other by only one flow passage 122a. That is, the communication passage diameter between the first bypass passage 104 and the second and third bypass passages 105 and 106 is reduced.

On the other hand, when the spool 121 is located elsewhere in the spool storage portion 111, as shown in FIG. 20B, both the first and second oil passages 122 and 123 are connected to the bypass wall in the peripheral wall. Since the first bypass passage 104 and the second and third bypass passages 105 and 106 are disconnected from each other, the communication state between the first bypass passage 104 and the second and third bypass passages 105 and 106 is cut off.
As described above, the shapes of the bypass passages 104, 105, and 106 and the oil passages 122 and 123 are the same as those of the first bypass passage 104 and the second and third portions when the spool 121 is moved to a predetermined position in the spool storage portion 111. The bypass passages 105 and 106 are designed to be in a communication state, or the communication state is cut off.

  Furthermore, both when the spool 121 moves to the spring arrangement side and when the spool 121 moves to the spool operation section arrangement side, the first bypass path 104 and the second and third bypass paths 105 and 106 are in communication. However, when the spool 121 moves to the spring arrangement side, the communication passage diameter between the first bypass passage 104 and the second and third bypass passages 105 and 106 is made smaller. That is, the first oil passage 122 and the second oil passage 122 can be switched between the first oil passage 122 and the second oil passage 123 as the communication passage according to the position of the spool 121 in the spool storage portion 111. The path 123 functions as a variable orifice.

As in the first embodiment, the spool 121 is formed with first and second rods 45 and 46 that extend in the vehicle front-rear direction on both end faces, as shown in FIG. In the second embodiment, the second rod 46 is formed integrally with the end surface of the spool 121.
Further, similarly to the first embodiment, the end of the first rod 45 is attached with a spring 32 and an attenuator 33 along with the spring 32. Furthermore, the end of the second rod 46 is connected to the spool operation unit 130 as in the first embodiment. The spool operation unit 130 in the second embodiment has a different structure from the spool operation unit 50 in the first embodiment.

  As shown in FIGS. 18 and 19, the spool operation unit 130 in the second embodiment is provided in the crank portion 131, a connecting member 132 that connects the crank portion 131, the crank portion 131 and the second rod 46, and the crank portion 131. The mass member 133 includes an elastic force rotation restricting mechanism 134 that restricts rotation of the crank by an elastic force, and a ratchet mechanism 135 that restricts the rotation direction of the spring spring 134b of the elastic force rotation restricting mechanism 134.

The crank part 131 includes a substantially disc-shaped main body part 131a and an arm part 131b extending in the outer peripheral direction from a part of the outer peripheral part of the main body part 131a. A mass member 133 is attached to the end of the arm portion 131b. Here, the movement of the mass member 133 in the downward direction (clockwise direction in FIG. 18) is restricted by the stopper 136. That is, the mass member 133 is supported by the stopper 136 at the initial position.
In addition, the crank portion 131 is provided with a support shaft 131 c extending in the horizontal direction from one side surface of the main body portion 131 a, and the support shaft 131 c is attached to the case 31. Thereby, the crank part 131 is supported by the support shaft 131c so that it can rotate forward and backward.

  The elastic force rotation restricting mechanism 134 is disposed on the other side surface of the main body 131a of the crank portion 131 where the support shaft 131c is not provided. The elastic force rotation restricting mechanism 134 has a structure that applies an elastic force in one direction in which the crank portion 131 rotates (counterclockwise direction in FIG. 18). Specifically, the elastic force rotation restricting mechanism 134 includes a plurality of rod-shaped locking pins 134a arranged at predetermined intervals in the circumferential direction on the outer periphery of the main body 131a of the crank portion 131, and one end of the main body portion. A spring spring 134b having a predetermined length, which is an elastic body attached to the central portion of 131a and having a shape such that the other end, which is a free end, passes between the locking pins 134a. The mainspring 134b is attached to the main body 131a via a ratchet mechanism 135 (a hatched portion located on the side surface of the main body 131a of the crank portion 13). The ratchet mechanism 135 has a structure that allows the main spring 131b to rotate only in the one direction while the main body 131a rotates in the forward and reverse directions.

  As described above, since the elastic force rotation restricting mechanism 134 is disposed on the other side surface of the main body portion 131a of the crank portion 131, the mainspring spring 134b is also positioned on the other side surface side of the main body portion 131a of the crank portion 131. However, in order to make it easy to understand the state of the mainspring 134b when the crank portion 131 rotates, in FIG. 18 and FIGS. 21 and 22 described later, the mainspring 134b is connected to the one side surface of the main body 131a of the crank portion 131. It is described in.

  By providing the elastic force rotation restricting mechanism 134 and the ratchet mechanism 135 as described above, as long as a certain amount of rotational force in the one direction (counterclockwise direction in FIG. 18) does not act on the crank portion 131, the crank portion 131. Does not move in the one direction. However, when a rotational force of a certain level or more is applied to the crank portion 131 in the one direction, the other end of the mainspring spring 134b is detached from the locking pin 134a and is caught by the locking pin 134a immediately adjacent to the locking pin 134a. It becomes like this.

The crank portion 131 can be rotated independently of the mainspring spring 134b by the ratchet mechanism 135 in the opposite direction (clockwise direction in FIG. 18), so that it can be rotated without being affected by the elastic force of the mainspring spring 134b. It has become.
As in the first embodiment, one end of the connecting member 132 is rotatably connected to the second rod 46, and the other end is provided on the side surface of the main body 131a of the crank portion 131. The slide pin 131d is slidably connected to the slide pin 131d. Specifically, a rectangular slide hole 132a is formed on the other end side of the connecting member 132, and the slide pin 131d of the main body 131a of the crank portion 131 is inserted into the slide hole 132a. .

  As a result, as shown in FIG. 18, the mass member 133 is moved upward (counterclockwise in FIG. 18) from the state where the downward movement of the mass member 133 is restricted by the stopper 136 (initial position state). In the moving scene, the main body 131a also rotates in conjunction with the movement of the mass member 133, so that the slide pin 131d moves in the slide hole 132a of the connecting member 132, and then the inside of the slide hole 132a. As a result, the connecting member 132 and further the second rod 46 (or the spool 121) move.

  On the other hand, from the state in which the second rod 46 (or the spool 121) is moved with the slide pin 131d applied to the inner end of the slide hole 132a of the connecting member 132, the mass member 133 is moved downward (see FIG. 18, when the main body 131 a rotates in the opposite direction, the slide pin 131 d has a so-called play in the slide hole 132 a of the connecting member 132. Regardless of the above, the second rod 46 (or the spool 121) moves. In this case, the second rod 46 (or the spool 121) moves to the spring arrangement side depending on the damping force of the damper 33 and the biasing force of the spring 32.

In the second embodiment, the damping force of the attenuator 33 is different in the moving direction of the spool 121. Specifically, the damping force is increased when the spool 121 moves to the spring arrangement side than when the spool 121 moves to the spool operation section arrangement side.
As described above, the damping force control unit 30 in the second embodiment is configured.

Next, the operation and damping force characteristics of the shock absorber 1 will be described.
21 and 22 show the configuration of the damping force control unit 30. FIG. FIG. 21 shows the operation of the shock absorber 1 when the wheel rides over the protrusion (convex road) on the traveling road, and FIG. 22 shows the operation of the shock absorber 1 immediately after the wheel gets over the protrusion on the traveling road.

(1) When the vehicle is traveling on a flat road First, when the vehicle is traveling on a flat road, the mass member 133 is positioned on the stopper 136 as shown in FIG. The spool 121 is brought into contact with the side surface on the spring arrangement side of the spool storage portion 111 by the urging force of the spring 32. As a result, as shown in FIG. 20A, the first bypass passage 104 and the second and third bypass passages 105 and 106 are connected via the bypass passages 113 and 114 in the peripheral wall of the spool storage portion 111. Since the first oil passage 122 communicates with the single flow passage 122a, the communication passage is in a small communication passage diameter.

  As an operation at the time of expansion / contraction of the shock absorber 1 at this time, when the piston rod 6 or the piston valve 5 moves in the vertical direction, the first liquid chamber 10 and the second liquid are passed through the bypass passages 104, 105, 106 and the like. Hydraulic fluid flows between the chamber 11. This flow generates a damping force in the shock absorber 1.

(2) When the wheel passes over the protrusion (convex road) on the road If the wheel passes over the protrusion (convex road) on the road (instantaneous when it gets over), the shock absorber 1 generates upward acceleration. As shown in FIG. 21A, an upward external force acts on the mass member 133 positioned on the stopper 136 so that the crank portion 131 rotates in one direction (counterclockwise in FIG. 21). become. At this time, if the upward external force acting on the mass member 133 reaches a certain level, the crank portion 131 rotates against the urging force of the elastic force rotation restricting mechanism 134. As a result, as shown as a change from FIG. 21 (b) to FIG. 21 (c), the slide pin 131d moves in the slide hole 132a of the connecting member 132 and hits the inner end of the slide hole 132a. When the crank portion 131 further rotates, as shown in FIG. 21 (d), the second rod 46 is drawn toward the spool operation portion 130, so that the spool 121 moves toward the spool operation portion 130. .

At this time, as described above, since the damping force of the attenuator 33 is small, the spool 121 moves, that is, the crank portion 131 rotates without being affected by the damping force of the attenuator 33.
In this way, as the spool 121 moves, the first bypass passage 104 and the second and third bypass passages 105 and 106 are formed in the peripheral wall of the spool housing portion 111 as shown in FIG. Since the two fluid passages 123a and 123b constituting the second oil passage 123 are communicated with each other via the bypass passages 113 and 114, the communication passages are communicated with a large communication passage diameter.

As the operation at the time of expansion / contraction of the shock absorber 1 at this time, when the piston rod 6 or the piston valve 5 moves in the vertical direction, the bypass passages 104, 105, The hydraulic fluid flows between the first liquid chamber 10 and the second liquid chamber 11 through 106 and the like. This flow generates a damping force in the shock absorber 1.
However, since the first bypass passage 104 and the second and third bypass passages 105 and 106 are in communication with each other with a large communication passage diameter, that is, the first bypass passage 104 and the second and third bypass passages. Since the roads 105 and 106 are in a state equivalent to communication with a large-diameter orifice, the damping force is a damping generated in the shock absorber 1 when the vehicle is traveling on a flat road. Smaller than force.

(3) Immediately after the wheels have passed over the protrusions (convex roads) on the travel road Immediately after the wheels have passed over the protrusions (convex roads) on the travel road, the weight of the mass member 133 is dominant. As shown as a change from FIG. 21D to FIG. 22A, the crank 131 rotates in the opposite direction (clockwise direction in FIG. 21), and as shown in FIG. 22B. Then, the crank portion 131 rotates until the mass member 133 hits the stopper 136.

  Here, as described above, the spring 32 and the attenuator 33 are attached to the first rod 45, and the slide pin 131d has a so-called play in the slide hole 132a of the connecting member 132. The movement of the spool 121 as shown as a change from FIG. 22C to FIG. 22C moves slowly depending on the biasing force of the spring 32, but is slow because the attenuator 33 is large. At this time, since the slide pin 131d moves in the slide hole 132a of the connecting member 132, the spool 121 moves regardless of the rotation of the crank portion 131.

  As a result, as shown in FIG. 20B, the communication between the first bypass passage 104 and the second and third bypass passages 105 and 106 is temporarily interrupted (a certain period of time). As shown in FIG. 20 (a), the first bypass passage 104 and the second and third bypass passages 105, 106 are in communication with each other with a small communication passage diameter.

  Therefore, in a state where communication between the first bypass passage 104 and the second and third bypass passages 105 and 106 is temporarily interrupted, the first liquid chamber 10 and the second liquid chamber 11 are connected to the bypass passages 104, 105, Since the communication state via 106 and the like is cut off, when the shock absorber 1 is expanded or contracted, the damping force generating portion of the piston valve 5 is activated to generate a damping force in the shock absorber 1. That is, as the operation at the time of expansion and contraction of the shock absorber 1, when the piston rod 6 or the piston valve 5 moves in the vertical direction, the pressure difference between the pressure in the first liquid chamber 10 and the pressure in the second liquid chamber 11 A damping force is generated in the shock absorber 1 due to the hydraulic fluid flowing between the first liquid chamber 10 and the second liquid chamber 11 via the damping force generating portion of the piston valve 5. The damping force at this time is larger than the damping force when the vehicle is traveling on a flat road or when the wheel passes over a protrusion (convex road) (instantaneous).

  After that, as in the case where the vehicle is traveling on a flat road, the first bypass path 104 and the second and third bypass paths 105 and 106 are in communication with each other with a small communication path diameter. As a result, when the piston rod 6 or the piston valve 5 moves in the vertical direction as an operation when the shock absorber 1 is expanded and contracted, the first liquid chamber 10 and the second liquid are passed through the bypass passages 104, 105, 106 and the like. The hydraulic oil flows between the chamber 11. This flow generates a damping force in the shock absorber 1. However, the damping force is smaller than the immediately preceding damping force.

  As described above, the shock absorber 1 reduces the damping force during the time when the wheel is over the protrusion on the road based on the vertical acceleration generated in the vehicle when the wheel gets over the protrusion on the road. The damping force is smaller than that when the wheel is traveling, and the damping force immediately after the wheel gets over the protrusion on the traveling road is larger than the damping force when the wheel is traveling on the flat road. Thus, the shock absorber 1 is configured such that the damping force changes in one step when the wheel gets over the protrusion on the travel path.

  Here, FIG. 23 shows the damping force characteristics of the shock absorber 1 before and after the wheel over the projection on the road, and the spindle of the wheel before and after the wheel over the projection on the road. Shows the change in acceleration (vibration). The relationship between the damping force of the shock absorber 1 and the acceleration of the spindle is, for example, that if the damping force of the shock absorber is large, the acceleration of the spindle is small even though the external input from the road surface to the wheel is large. Become.

  In FIG. 23, the solid line indicates the damping force characteristic (spindle acceleration characteristic) of the conventional shock absorber, and the dotted line indicates the damping force characteristic (spindle acceleration characteristic) of the shock absorber 1 to which the present invention is applied. Further, in FIG. 23, a two-dot chain line indicates a protrusion shape on the traveling path through which the wheel passes. Further, in FIG. 23, the acceleration of the spindle in the area A is an initial one in which the wheel is going to get over the protrusion on the traveling road, and the acceleration of the spindle in the area B is that the wheel gets over the protrusion on the traveling road. The acceleration of the spindle in the C region is the one immediately after the wheel has passed over the protrusion on the road, and the acceleration of the spindle in the D region is when the wheel returns to a completely flat road after that. Is.

  As shown in FIG. 23, in both the conventional shock absorber (solid line) and the shock absorber (dotted line) to which the present invention is applied, the wheel is roughly in the initial stage of overcoming the protrusion on the travel path (region A). At the end of the shock), the shock absorber contracts and acceleration (upward acceleration) is generated on the spindle. While the wheel is over the protrusion on the road (B area), the shock absorber extends and reverses to the spindle. Acceleration in the direction (downward acceleration) occurs, and on the flat road immediately after the wheel has passed over the protrusion on the road (C area and D area), the spindle acceleration (vertical direction in the vertical direction) is caused by the damping force of the shock absorber. Acceleration) converges to zero.

  However, when comparing the conventional shock absorber (solid line) and the shock absorber (dotted line) to which the present invention is applied, the acceleration exceeding a certain threshold is detected while the wheel is over the protrusion on the road (B region). Since the damping force of the shock absorber to which the present invention is applied is reduced by rotating the crank portion 131 against the urging force generated by the elastic force rotation restricting mechanism 134 generated in the vehicle body (or the spindle), the acceleration of the spindle Furthermore, the damping force of the shock absorber to which the present invention is applied is greater immediately after the wheels have passed over the protrusions on the road and on flat roads thereafter (C region and D region). But the spindle acceleration can be suppressed. That is, in the shock absorber to which the present invention is applied, the acceleration (vibration) of the spindle is suppressed, and as a result, the vehicle body is prevented from shaking (vibration) when the wheel gets over the protrusion on the travel path.

For example, the hatched region in FIG. 23 shows the vibration suppression effect obtained as a result of controlling the damping force of the shock absorber 1 by applying the present invention.
Needless to say, the second embodiment can achieve the same effects as those of the first embodiment.
That is, for example, also in the shock absorber 1 of the second embodiment, the damping force is controlled by the bypass passages 104, 105, 106, the bypass passage communication on / off portion 110 including the spool 121, and the spool operation portion 130. Is going. Thereby, the shock absorber 1 realizes damping force control with a simple configuration. As a result, since there is no need to provide a resonance portion between the piston rod and the vehicle body as in the conventional case, the degree of freedom in the design of the vehicle body, for example, the shape of the engine room, can be increased, and the suspension stroke can also be increased. it can. That is, for example, the shock absorber 1 can be attached to the vehicle without affecting the component characteristics (hood height, upper mount characteristics, bumper rubber characteristics, etc.) around the upper mount.

  In the second embodiment, the communication path between the first liquid chamber 10 and the second liquid chamber 11 is defined as the first oil path based on the vertical acceleration generated in the vehicle when the wheel gets over the protrusion on the travel path. The case where the damping force of the shock absorber 1 is changed by switching the area of the communication path between the first liquid chamber 10 and the second liquid chamber 11 by switching between 122 and the second oil passage 123 has been described. However, it is not limited to this. For example, the area of the communication path (second and third bypass paths 105, 106) between the second liquid chamber 11 and the reservoir chamber 7 is determined based on the vertical acceleration generated in the vehicle when the wheel gets over the protrusion on the travel path. The damping force of the shock absorber 1 may be changed by adopting a switchable structure.

  Further, in the description of the second embodiment, the mass member 133 realizes a mass member that moves by generating vertical acceleration greater than a predetermined threshold in the vehicle when the wheel gets over the protrusion on the travel path. The spool (spool valve) 121 has an area of at least one of the first and second flow paths while the wheel is running over a protrusion on the travel path, and the wheel travels on a flat road. An opening / closing valve that closes the flow path whose area has been changed is realized immediately after the wheel has moved over the protrusion on the travel path.

It is sectional drawing which shows the structure of the shock absorber of embodiment of this invention. It is a front view which shows the structure of the shock absorber of the 1st Embodiment of this invention. It is a figure which shows the structure of the damping force control part of the shock absorber of the said 1st Embodiment, 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 the said 1st Embodiment, and is a figure which shows the state which interrupted | blocked the communication state of an oil path and each bypass path. It is a figure which shows the state which the said oil path and each bypass path connected. It is a figure which shows the state by which the communication with the said oil path and each bypass path was interrupted | blocked. It is a figure which shows the structure of the damping force control part of the shock absorber of the said 1st Embodiment, 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 It is a figure which shows the state which the member extended as a link mechanism. It is the figure used for description of the state change of the spool according to the driving | running | working state of a vehicle, and a spool operation part. It is a figure which shows the driving | running | working state of a vehicle, (a) in a figure shows a turning state, (b) shows a straight running state. FIG. 6 is a characteristic diagram showing a difference in damping force of the shock absorber between when the vehicle is turning and when traveling straight. It is a characteristic view which shows the relationship between a lateral acceleration and the moving speed of a spool. It is a characteristic view which shows the relationship between a spool position (orifice opening degree) and the damping force of a shock absorber. It is the figure used for description of the characteristic of the damping force of a shock absorber when driving on a continuous curve. It is a characteristic view which shows the relationship between a lateral acceleration and damping force ratio. It is a figure which shows the structure of the spool operation part comprised by the connecting rod mechanism. It is a figure which shows the structure of the bypass channel communication ON and OFF part comprised including a rotary valve and rotary valve operation. It is a front view which shows the structure of the shock absorber of the 2nd Embodiment of this invention. It is a front view which shows the structure of the damping force control part of the shock absorber of the said 2nd Embodiment. It is a figure which shows the structure of the damping force control part of the shock absorber of the said 2nd Embodiment seen from arrow BB in the said FIG. It is a figure which shows the communication state of the oil path and each bypass path in the damping force control part of the shock absorber of the said 2nd Embodiment. It is the figure used for description of the state change of the spool and spool operation part in the damping force control part of the shock absorber of the said 2nd embodiment when a wheel gets over the protrusion (convex road) on a travel path. It is the figure used for description of the state change of the spool and spool operation part in the damping force control part of the shock absorber of the said 2nd embodiment immediately after a wheel overcame the protrusion (convex road) on a travel path. It is a characteristic view which shows the change of the acceleration (vibration) of the spindle of a wheel before and after a wheel gets over the protrusion on a running path. It is a figure which shows the structure of the shock absorber for vehicles currently disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shock absorber 2 Inner cylinder 3 Outer cylinder 4 Cylinder 5 Piston valve 6 Piston rod 7 Reservoir chamber 8 Base valve 10, 11 Fluid chamber 30 Damping force control part 32 Spring 33 Attenuator 34, 35, 36 Bypass path 40 Bypass path communication ON And off part 42 Spool 45,46 Rod 46a Piston part 50 Spool operation part 51,52 Link member 53 Mass member

Claims (9)

A piston rod connected to the vehicle body side member;
A cylinder connected to the wheel side member and composed of an inner cylinder and an outer cylinder;
A piston internally connected to the inner cylinder so as to divide the inner cylinder into a first chamber and a second chamber, and connected to a piston rod inserted from one end of the cylinder;
A reservoir chamber in communication with the second chamber;
A first valve for flowing hydraulic fluid between the second chamber and the reservoir chamber;
A shock absorber for a vehicle provided with a second valve that is provided in the piston and allows a working fluid to flow between the first chamber and the second chamber,
A mass member that moves due to acceleration generated in the vehicle;
A first flow path communicating the first chamber and the second chamber;
A second flow path communicating the second chamber and the reservoir chamber;
An on-off valve for opening and closing the first channel and the second channel;
A connection mechanism that connects the on-off valve and the mass member, and switches the on-off state of the on-off valve in conjunction with the movement of the mass member by the acceleration;
A vehicle shock absorber. 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 that opens the spool valve; and an attenuator that is attached to the spring and applies a damping force to the spool valve when the spool valve moves. The vehicle shock absorber according to claim 1.   3. The shock absorber for a vehicle 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. An opening on an end surface of the spool valve, and a hollow portion formed in the spool valve, extending in a moving direction of the spool valve, and having an inner diameter larger than an opening diameter of the opening communicating with the opening. The connecting rod includes a locking portion having a convex shape in a radial direction at one end inserted through the opening from the opening.
The coupling mechanism moves the coupling rod in the movement direction of the spool valve in conjunction with the movement of the mass member due to the acceleration, so that the opening diameter of the locking portion is made larger than the inner diameter of the empty portion. 4. The vehicle shock absorber according to claim 3, wherein the shock absorber is engaged with an outer peripheral portion of the opening to be reduced and moved to a position where the spool valve is closed.   5. The vehicle shock absorber according to claim 1, wherein the mass member is moved by lateral acceleration generated in the vehicle. 6. The mass member is adapted to move when vertical acceleration greater than a predetermined threshold is generated in the vehicle when the wheel gets over the protrusion on the travel path,
The on-off valve has an area of at least one of the first and second flow paths while the wheel is running over a protrusion on the travel path. The vehicle shock absorber according to any one of claims 1 to 3, wherein the flow path with the changed area is closed immediately after the wheel is made larger than the one and the wheel climbs over the protrusion on the traveling road. The mass member is attached to the outer peripheral side with respect to the center of rotation, and a rotating body that rotates due to vertical acceleration occurring in the vehicle when a wheel climbs over the protrusion on the travel path, and one end of the rotating body A plurality of rod-like elastic bodies attached to the central portion and extending in the radial direction of the rotating body, and arranged closer to the center of the rotating body than the other end of the elastic body and in the circumferential direction of the rotating body With a locking pin,
When the vertical acceleration is equal to or lower than a predetermined threshold, the other end of the elastic body is locked to the locking pin, so that the movement of the mass member is limited, and the vertical acceleration is less than the predetermined threshold. If the length of the elastic member is larger, the elastic member is elastically deformed, and the other end of the elastic member is removed from the locking pin, so that the restriction on the movement of the mass member is released. Shock absorber for vehicles. The mass member is configured to reciprocate within a predetermined range, and after the wheel has climbed over the protrusion on the travel path, the mass member returns to the initial position before the wheel has climbed over the protrusion on the travel path. And the rotating body is supported so that it can rotate forward and reverse in conjunction with the reciprocating movement of the mass member,
By connecting the central portion of the rotating body and one end of the elastic body by a ratchet structure, the elastic body is only in the rotation direction in which the rotating body starts rotating when a wheel gets over the protrusion on the traveling path. The vehicle shock absorber according to claim 7, wherein the vehicle shock absorber rotates together with the rotating body.   Based on the vertical acceleration generated in the vehicle when the wheel gets over the protrusion on the road, the damping force while the wheel gets over the protrusion on the road is attenuated when the wheel is running on the flat road. A shock absorber for a vehicle, wherein the damping force is made smaller than the force, and the damping force immediately after the wheel gets over the protrusion on the running road is larger than the damping force when the wheel is running on the flat road.

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