JP5897955B2 - Damping force adjustable shock absorber - Google Patents

Description

  The present invention relates to a damping force adjusting type shock absorber that is suitably used for buffering vibrations of, for example, an automobile.

  A vehicle such as a four-wheeled vehicle is provided with a damping force adjusting type shock absorber between the wheel side and the vehicle body side, and is configured to buffer upward and downward vibrations and the like generated during traveling. This damping force adjusting type shock absorber makes two cylinder chambers communicate with each other by a main passage and a bypass passage, and controls the flow of fluid generated in the main passage and the bypass passage by sliding of a piston in the cylinder, thereby reducing the damping force. The damping force is adjusted by adjusting the passage area of the bypass passage with a damping force adjusting valve.

  The damping force adjusting valve includes a cylindrical guide member having a guide port on a side wall, and a shutter member having a shutter port that is rotatably fitted in the guide member and faces the guide port on the side wall. (For example, refer to Patent Document 1).

JP 7-77233 A

  By the way, in the damping force adjusting type shock absorber according to Patent Document 1 described above, when the area of the passage formed by the guide port and the shutter port is small, the flow velocity of the fluid passing through the passage becomes very high. In this way, when the fluid flows at a high speed, the pressure decreases, and when the low pressure at this time acts on the inner surface of the shutter port, a fluid force acts to rotate the shutter member due to the pressure difference from the surroundings, and the shutter member There is a problem that the accuracy of the positioning control is deteriorated.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to improve the accuracy of positioning control of the shutter member by reducing the fluid force acting on the inner surface of the shutter port. It is to provide a damping force adjustable shock absorber.

In order to solve the above-described problems, the present invention controls two fluid flow in the main passage and the bypass passage by connecting two cylinder chambers through the main passage and the bypass passage and sliding the piston in the cylinder. In the damping force adjusting type shock absorber, wherein damping force can be adjusted by generating damping force and adjusting the passage area of the bypass passage by the damping force adjusting valve, the damping force adjusting valve has a guide port on a side wall. A cylindrical guide member, and a shutter member that is rotatably fitted in the guide member and has a shutter port facing the guide port on a side wall, the outer peripheral surface of the side wall of the shutter member being the guide rotatably formed as a cylindrical body that is inserted into the member, of the side wall of the shutter member, meat portion the shutter port is formed And formed thinner than the thickness of the other portions, of the inner peripheral surface of the side wall, it has a configuration forming the thin wall thickness by recessed a portion the shutter port is formed on the outer diameter side.

  With the above configuration, the fluid force acting on the inner surface of the shutter port can be reduced, so that the accuracy of the shutter member positioning control can be improved.

1 is a longitudinal sectional view showing a damping force adjustment type hydraulic shock absorber according to an embodiment of the present invention. It is a longitudinal cross-sectional view which expands and shows the piston, subpiston, damping force adjustment valve, etc. in FIG. It is a front view which expands and shows a shutter member by itself. It is the top view which looked at the shutter member from the upper side. It is the cross-sectional view which looked at the shutter member from the arrow VV direction in FIG. It is the longitudinal cross-sectional view which looked at the shutter member from the arrow VI-VI direction in FIG. It is the longitudinal cross-sectional view which looked at the shutter member from the arrow VII-VII direction in FIG. It is a cross-sectional view showing a state where a passage having a small area is formed by the guide port of the guide member and the shutter port of the shutter member.

  Hereinafter, a case where the damping force adjusting shock absorber according to the embodiment of the present invention is applied to a damping force adjusting hydraulic shock absorber for a vehicle will be described as an example, and will be described in detail with reference to FIGS.

  In FIG. 1, a cylindrical cylinder 1 forms an outer shell of a single cylinder type damping force adjusting hydraulic shock absorber, and a lower end portion of the cylinder 1 is closed by a bottom cap 2. A rod guide 3 for guiding a piston rod 7 described later is provided on the upper end side of the cylinder 1, and an upper cap 4, a spring receiver 5 and the like are attached so as to cover the rod guide 3. The spring receiver 5 supports a suspension spring (not shown) of the vehicle from below.

  A piston 6 is movably fitted in the cylinder 1, and the piston 6 defines the inside of the cylinder 1 in two chambers, a rod-side oil chamber A and a bottom-side oil chamber B as a cylinder chamber. . The piston 6 is formed with a plurality of oil passages 6A, 6B that can communicate with the rod-side oil chamber A and the bottom-side oil chamber B, respectively, spaced apart in the circumferential direction. The oil passages 6A, 6B It is comprised by the oil hole inclined diagonally with respect to 6 axis lines. The oil passages 6 </ b> A and 6 </ b> B constitute a main passage through which the oil liquid as the working fluid sealed in the cylinder 1 flows between the rod side oil chamber A and the bottom side oil chamber B.

  As shown in FIG. 2, the upper end surface of the piston 6 has an annular recess 6C formed so as to surround the upper opening of the oil passage 6A, and a compression-side damping, which will be described later, located on the radially outer side of the annular recess 6C. An annular valve seat 6D on which the valve 13 (disc valve) is seated is provided. An annular recess 6E formed so as to surround the lower opening of the oil passage 6B is formed on the lower end surface of the piston 6, and an expansion-side damping valve 14 (disc valve), which will be described later, is located radially outside the annular recess 6E. Is provided with an annular valve seat 6F.

  A piston rod 7 extends in the cylinder 1 in the axial direction. The piston rod 7 includes a cylindrical rod member 8 having a lower end inserted into the cylinder 1 and a cylindrical joint member below the rod member 8. 9 and a stepped cylindrical guide member 10 connected via 9. The joint member 9 constitutes a part of the piston rod 7 and also serves as a spring receiver for a spring 34 described later.

  The piston 6 is attached to the lower end side of the piston rod 7, that is, the lower end side of the guide member 10 in a state of being fastened by a nut 11 or the like. The nut 11 fixes the piston 6 to the guide member 10 and detachably fastens a compression-side damping valve 13 and an expansion-side damping valve 14 (described later) on the upper and lower surfaces of the piston 6. On the other hand, the upper end side of the piston rod 7, that is, the upper end side of the rod member 8 protrudes outside the cylinder 1 through the rod guide 3, the upper cap 4, and the like.

  The guide member 10 is formed as a stepped cylindrical body composed of a cylindrical side wall 10A extending upward and downward, and a pin insertion hole through which a pin member 30 described later is inserted with a gap is formed on the inner peripheral side of the side wall 10A. 10B and a shutter insertion hole 10C which is positioned below the pin insertion hole 10B and extends in the axial direction and has a larger diameter than the pin insertion hole 10B. Further, a pin insertion hole (not shown) is also provided on the inner peripheral side of the rod member 8 so as to communicate with the pin insertion hole 10B of the guide member 10 in the axial direction. The pin insertion hole The pin member 30 is also inserted in the inside with a gap.

  The shutter insertion hole 10 </ b> C of the guide member 10 has an opening end 10 </ b> D whose lower end side always communicates with the bottom side oil chamber B. A shutter member 23, which will be described later, is rotatably fitted in the shutter insertion hole 10C. The upper end of the shutter insertion hole 10C communicates with the pin insertion hole on the rod member 8 side via the pin insertion hole 10B in the upward and downward directions, and the pin insertion hole 10B and the shutter insertion hole 10C are arranged substantially coaxially. Has been.

  The guide member 10 of the piston rod 7 constitutes a part of a damping force adjusting valve 22 described later. On the side wall 10A of the guide member 10, a plurality of guide ports 10E, 10F and the like extending radially outward from the shutter insertion hole 10C and penetrating are provided apart from each other in the axial direction and the circumferential direction.

  Of these guide ports 10E, 10F, etc., each guide port 10E located on the upper side is disposed at a position communicating in a radial direction with a recessed portion 15G of a sub-piston 15 described later. That is, each guide port 10E is configured by a total of two radial holes formed at positions facing each other in the radial direction at intervals of 180 degrees in the circumferential direction of the side wall 10A.

  On the other hand, each guide port 10F located on the lower side is disposed at a position where it communicates in the radial direction with a cylindrical spacer 19 in an intermediate chamber D described later. Similarly to the guide port 10E described above, the guide port 10F is configured by a total of two radial holes formed at positions opposed to each other in the radial direction at intervals of 180 degrees in the circumferential direction of the side wall 10A. Yes. Furthermore, a stepped portion 10G for positioning a spacer 18 (described later) in the axial direction is formed on the outer periphery of the upper portion of the guide member 10 in an enlarged diameter.

  As shown in FIG. 1, a free piston 12 is slidably inserted into the cylinder 1 between the piston 6 and the bottom cap 2. The free piston 12 defines a gas chamber C in which pressurized gas is sealed on the bottom side of the cylinder 1. Here, the free piston 12 is pivoted in the cylinder 1 so that the gas chamber C is contracted and expanded in response to the piston rod 7 entering or leaving the cylinder 1. Sliding displacement in the direction. That is, the free piston 12 expands and contracts the gas chamber C so as to compensate for the entry volume of the piston rod 7.

  Reference numeral 13 denotes a reduction-side damping force generation mechanism (hereinafter referred to as a compression-side damping valve 13) provided on the upper surface side of the piston 6, and the compression-side damping valve 13 is a rod-side oil of the cylinder 1 as shown in FIG. It is composed of a plurality of disk valves and the like that are located in the chamber A and are fixedly attached to the upper surface side of the piston 6. The compression-side damping valve 13 (disc valve) is formed with a small notch 13A that forms a fixed orifice with the annular valve seat 6D. The notch 13A is configured so that the oil fluid on the oil passage 6A side is the rod-side oil. It is allowed to flow toward the chamber A even when the compression side damping valve 13 is closed. In addition, it is good also as a structure which replaces with the notch 13A and provides the fixed orifice which consists of a notch etc. in the annular valve seat 6D side.

  When the piston 6 slides downward in the cylinder 1 during the reduction stroke of the piston rod 7, the compression side damping valve 13 passes from the bottom side oil chamber B through the oil passages 6 </ b> A of the piston 6 and the annular recess 6 </ b> C. A resistance force is given to the oil liquid flowing toward the rod-side oil chamber A, and a preset contraction-side damping force is generated.

  Reference numeral 14 denotes an extension side damping force generation mechanism (hereinafter referred to as an extension side damping valve 14) provided on the lower surface side of the piston 6. The extension side damping valve 14 is located in the bottom side oil chamber B of the cylinder 1. It is composed of a plurality of disc valves and the like attached to the lower surface side of the piston 6 in a fixed state. The expansion side damping valve 14 (disc valve) is formed with a small notch 14A that forms a fixed orifice with the annular valve seat 6F. The notch 14A is configured such that the oil on the oil passage 6B side is bottom oil. The flow toward the chamber B is allowed even when the expansion side damping valve 14 is closed. Instead of the cutout 14A, a fixed orifice made of a cutout or the like may be provided on the annular valve seat 6F side.

  When the piston 6 slides upward in the cylinder 1 during the extension stroke of the piston rod 7, the extension-side damping valve 14 moves from the rod-side oil chamber A through the oil passages 6B of the piston 6 and the annular recess 6E. A resistance force is given to the oil liquid flowing toward the bottom-side oil chamber B, and a preset extension-side damping force is generated.

  A sub piston 15 is provided in the guide member 10 of the piston rod 7 and is located in the rod side oil chamber A. The sub piston 15 is disposed on the compression side damping valve 13 of the piston 6 via a cap member 20 and a cylindrical spacer 19 which will be described later. The sub-piston 15 has an outer diameter dimension smaller than the inner diameter of the cylinder 1 and is disposed in the cylinder 1 in a non-sliding state (that is, a state having a gap in the radial direction).

  The sub piston 15 defines an intermediate chamber D between the sub piston 15 and the cap member 20, and the intermediate chamber D constitutes a part of a bypass passage 21 described later. The sub-piston 15 is formed with a plurality of oil passages 15A and 15B that can communicate with the rod-side oil chamber A and the intermediate chamber D, respectively, spaced apart in the circumferential direction. It is constituted by an oil hole inclined obliquely with respect to 15 axes. The oil passages 15 </ b> A and 15 </ b> B constitute a passage (a part of the bypass passage 21) through which the oil liquid flows between the rod-side oil chamber A and the intermediate chamber D.

  An annular recess 15C formed so as to surround the upper opening of the oil passage 15A and an annular valve located on the radially outer side of the annular recess 15C and seated on the reduction side disk valve 16 are attached to the upper end surface of the sub-piston 15. A seat 15D is provided. An annular recess 15E formed so as to surround the lower opening of the oil passage 15B and an extension-side disk valve 17 positioned on the radially outer side of the annular recess 15E are seated on the lower end surface of the sub-piston 15. An annular valve seat 15F is provided.

  A notch (not shown) is provided between the reduction-side disc valve 16 and the annular valve seat 15D as a fixed orifice that allows oil to flow even when the reduction-side disc valve 16 is closed. Similarly, a notch (not shown) as a fixed orifice is provided between the extension-side disc valve 17 and the annular valve seat 15F.

  Further, on the inner peripheral side of the sub-piston 15, an annular recess 15 </ b> G having a lower surface communicating with the annular recess 15 </ b> E and an upper surface serving as a closed end is provided. The recessed portion 15G is formed so as to surround the guide port 10E of the guide member 10 from the outside in the radial direction, and always communicates the guide port 10E with the annular recessed portion 15E of the sub piston 15 and the oil passage 15B.

  Reference numeral 18 denotes a spacer provided between the stepped portion 10G of the guide member 10 and the reduction-side disk valve 16, and the spacer 18 is constituted by an annular body provided by being fitted to the outer peripheral side of the guide member 10. Yes. The spacer 18 sandwiches the reduction-side disk valve 16 with the step portion 10G, and stabilizes the opening and closing operations of the reduction-side disk valve 16.

  Reference numeral 19 denotes a cylindrical spacer for positioning the extension-side disk valve 17 on the lower surface side of the sub-piston 15, and the cylindrical spacer 19 is configured by a covered cylindrical body that is provided so as to pass through the outer peripheral side of the guide member 10. Yes. The cylindrical spacer 19 sandwiches the extension-side disc valve 17 from the lower side with the annular valve seat 15F of the sub-piston 15, and stabilizes the opening and closing operations of the extension-side disc valve 17. The cylindrical spacer 19 is formed with a plurality of notches 19A as communication holes at intervals in the circumferential direction, and the notches 19A always communicate the intermediate chamber D with the guide ports 10F of the guide member 10. Is.

  Reference numeral 20 denotes a cap member that defines an intermediate chamber D with the sub-piston 15. The cap member 20 is positioned on the lower surface side, is inserted into the outer peripheral side of the guide member 10 and is sandwiched between the compression-side damping valve 13 and the cylindrical spacer 19, and the outer peripheral side of the bottom portion 20A. An inclined cylinder portion 20B extending upward while being expanded from a cylindrical portion, and a cylindrical cylindrical portion 20C extending upward from the outer peripheral side of the inclined cylinder portion 20B. The cap member 20 is fitted in a liquid-tight state at the upper end side of the cylindrical portion 20 </ b> C to the outer peripheral side of the sub-piston 15, whereby an intermediate chamber D is defined between the cap member 20 and the sub-piston 15.

  The cap member 20 has an outer diameter smaller than the inner diameter of the cylinder 1 and is disposed with a gap from the inner peripheral surface of the cylinder 1. The cap member 20 is fixed to the guide member 10 of the piston rod 7 via the sub-piston 15 and the cylindrical spacer 19. The cap member 20 moves up the cylinder 1 together with the sub-piston 15 and the cylindrical spacer 19. It moves downward.

  Reference numeral 21 denotes a bypass passage formed between the guide member 10 of the piston rod 7 and the sub piston 15. The bypass passage 21 includes oil passages 15A and 15B of the sub piston 15, annular recesses 15C and 15E, a recess 15G, a shutter insertion hole 10C of the guide member 10, guide ports 10E and 10F, and the like. As a result, the bypass passage 21 bypasses the main passage of the piston 6, that is, the oil passages 6A and 6B, and connects the rod-side oil chamber A and the bottom-side oil chamber B between the shutter ports 27 and 28 described later. To communicate with each other.

  Reference numeral 22 denotes a damping force adjusting valve that variably adjusts the damping force by changing the passage area of the bypass passage 21. The damping force adjusting valve 22 includes the above-described guide member 10 that forms a part of the piston rod 7, the shutter member 23 that is rotatably inserted into the shutter insertion hole 10C of the guide member 10, and the shutter. A pin member 30 to be described later for rotating the member 23 is included.

  Here, the configuration of the shutter member 23 constituting the damping force adjusting valve 22 will be described in detail with reference to FIGS. 3 to 8.

  As shown in FIGS. 3, 6, 7, and the like, the shutter member 23 of the damping force adjusting valve 22 includes a side wall 24 made of a cylindrical body that is rotatably inserted into the shutter insertion hole 10 </ b> C of the guide member 10. A lid portion 25 that closes the upper end portion in the axial direction of the side wall 24; and a pin mounting cylinder 26 that is a small-diameter cylindrical body that extends in the axial direction from the lid portion 25 into the side wall 24. Yes.

  The side wall 24 of the shutter member 23 has an outer peripheral surface 24 </ b> A that slidably contacts the shutter insertion hole 10 </ b> C of the guide member 10. On the other hand, the inner side of the side wall 24 is an inner peripheral surface 24B, and the lower end portion of the inner peripheral surface 24B is an open end 24C communicating with the bottom side oil chamber B.

  As shown in FIG. 5, the side wall 24 is formed as a thick portion 24D having a thickness dimension t1 except for a part thereof. The thickness t1 of the thick portion 24D can maintain sufficient durability even in a severe use state where the shutter member 23 is rotated by an actuator (not shown) such as an electric motor and hydraulic pressure acts on various portions. The thickness dimension is set.

  On the other hand, a part of the side wall 24 is a thin portion 24E having a thickness dimension t2. The thin portion 24E is formed at a circumferential position (a position having an interval of 180 degrees in the circumferential direction) corresponding to a second shutter port 28 described later. Thereby, the thin-walled portion 24E can reduce the area of the inner surface 28D of the second shutter port 28 where the widened inclined portion 28B receives the low pressure.

  As shown in FIG. 4, a semicircular communication hole 25 </ b> A is formed in the lid portion 25 of the shutter member 23 so as to face each other. The communication hole 25A guides a part of the oil liquid to the bush 31 described later, thereby maintaining a lubrication and liquid-tight state between the bush 31 and the pin member 30. Thereby, since the gap between the pin insertion hole 10B of the guide member 10 and the pin member 30 is sealed by the bush 31, leakage of the oil liquid is prevented.

  As shown in FIGS. 6 and 7, the inner peripheral side of the pin mounting cylinder 26 is a rotation stop hole 26 </ b> A to which the mounting end 30 </ b> A of the pin member 30 is fitted and mounted in a rotation stopped state. As shown in FIG. 4, the inner portion (lower side) of the anti-rotation hole 26 </ b> A is formed as an oval shaped hole having a cross section.

  Here, on the side wall 24 of the shutter member 23, a first shutter port 27 that is communicated with and cut off from the guide port 10E disposed on the upper side of the guide member 10 and a lower side of the guide member 10 are disposed. A second shutter port 28 that is communicated with and cut off from the guide port 10F is provided.

  As shown in FIG. 6, the first shutter port 27 is configured as a radial through hole formed at a position facing each other at an interval of 180 degrees in the circumferential direction of the shutter member 23 (side wall 24). As shown in FIG. 3, in the first shutter port 27, one circumferential side is a slit-shaped narrow part 27A, a substantially middle part is a widened arc part 27B, and the other circumferential part is wider than the narrow part 27A. This is a wide part 27C. The area of the passage formed between the first shutter port 27 and the guide port 10 </ b> E of the guide member 10 can be changed by changing the width dimension in the circumferential direction. Thereby, the damping force according to the area of the passage can be generated, and the damping force can be adjusted according to the rotational position.

  Similar to the first shutter port 27 described above, the second shutter port 28 is configured as radial through holes formed at positions facing each other at an interval of 180 degrees in the circumferential direction of the shutter member 23. In this case, the second shutter port 28 is formed with a larger opening area than the first shutter port 27. As shown in FIGS. 3 and 7, in the second shutter port 28, one of the circumferential directions is a slit-like narrow portion 28A, the substantially middle portion is a widened inclined portion 28B, and the other circumferential portion is the narrow portion 28A. The wider portion 28 </ b> C is wider.

  The area of the passage formed between the second shutter port 28 and the guide port 10F of the guide member 10 can be changed by changing the width dimension in the circumferential direction. Thereby, the damping force according to the area of the passage can be generated, and the damping force can be adjusted according to the rotational position. Here, since the second shutter port 28 has a large difference in width between the narrow width portion 28A and the wide width portion 28C, the widened inclined portion 28B is formed to rise in the axial direction. Accordingly, the area of the passage formed between the second shutter port 28 and the guide port 10F of the guide member 10 is changed by changing the width dimension in the circumferential direction in substantially the same manner as the first shutter port 27. be able to. Thereby, the damping force according to the area of the passage can be generated, and the damping force can be adjusted according to the rotational position.

  Here, when the area of the passage formed between the guide port 10F of the guide member 10 and the second shutter port 28 is large, that is, when the guide port 10F and the wide portion 28C communicate with each other, this passage is provided. Since the oil liquid flows at a relatively low speed, the pressure does not change greatly.

  On the other hand, when the area of the passage formed between the guide port 10F of the guide member 10 and the second shutter port 28 is small, that is, when the guide port 10F and the narrow width portion 28A communicate with each other, this passage. Since the oil liquid flows at a high speed, the pressure decreases in the vicinity of this passage. As shown in FIG. 8, in such a situation, when the widening inclined portion 28B rising in the axial direction is disposed in the low pressure region, the inner surface 28D located in the widening inclined portion 28B receives the low pressure, and the surroundings It is conceivable that the shutter member 23 is rotated clockwise by the pressure difference between the two.

  However, in the present embodiment, by setting the position of the second shutter port 28 to the thin portion 24E of the side wall 24, the area of the inner surface 28D where the second shutter port 28 receives low pressure can be reduced. The fluid force acting on the port 28 can be reduced, and the rotation of the shutter member 23 can be suppressed to increase the positioning accuracy.

  The recessed portions 29 provided on the inner peripheral surface 24B of the side wall 24 are formed at positions where the second shutter port 28 is formed, that is, at positions facing each other at an interval of 180 degrees in the circumferential direction of the side wall 24. . As shown in FIG. 5, the two recessed portions 29 are formed by, for example, recessing the inner peripheral surface 24 </ b> B with an arc surface having an axis parallel to the axis of the side wall 24. Each recessed portion 29 is disposed in the vicinity of the widened inclined portion 28B of the second shutter port 28 so that the thickness of the side wall 24 is the thinnest (thickness dimension t2).

  Further, each recessed portion 29 (thin wall portion 24E of the side wall 24) is formed to extend from the second shutter port 28 to the opening end 24C of the side wall 24. Thereby, even when the shutter member 23 is manufactured using a molding process, the molding die (core) can be extracted from the opening end 24 </ b> C, and the recessed portions 29 can be provided on the side wall 24.

  Here, the second shutter port 28 forms a passage through which the oil liquid flows between the second shutter port 28 and the guide port 10 </ b> F of the guide member 10. In this case, by rotating the shutter member 23 to an arbitrary position with respect to the guide member 10, the area of the passage is changed according to the positions of the narrow portion 28A, the widened inclined portion 28B, and the wide portion 28C. As shown in FIG. 8, when the narrow port portion 28A to the wide inclined portion 28B of the second shutter port 28 are arranged at the position of the guide port 10F, the guide port 10F is throttled by the second shutter port 28. The area of the passage is small. Accordingly, the oil liquid circulates in the passage at high speed as indicated by arrow E.

  As described above, when the oil liquid flows through the passage between the guide port 10F and the second shutter port 28 at a high speed, the pressure in the vicinity of the passage decreases, and the inner surface of the passage, that is, the second shutter port 28 It acts on the inner surface 28D. At this time, since the low pressure also acts on the inner surface 28D at the position of the widening inclined portion 28B extending so as to rise in the axial direction of the shutter member 23, the fluid force due to the low pressure reduces the passage of the shutter member 23. It tries to rotate in the direction, that is, the direction of arrow F.

  However, the position of the widened inclined portion 28B of the second shutter port 28 is a thin portion 24E having a small thickness t2 by forming a recessed portion 29 on the inner peripheral surface 24B side of the side wall 24. Thereby, the inner surface 28D at the position of the widened inclined portion 28B where the low pressure acts is formed in the inner surface 28D of the second shutter port 28 so as to have a small area by the thin portion 24E. Therefore, the force by which the fluid force due to the low pressure tries to rotate the shutter member 23 in the direction indicated by the arrow F can be kept small, and the shutter member 23 can be fixed at a predetermined rotational position.

  The pin member 30 of the damping force adjusting valve 22 is provided so as to be inserted into the pin insertion hole 10 </ b> B of the rod member 8 and the guide member 10 in order to rotate the shutter member 23. The lower end portion of the pin member 30 is an attachment end portion 30A that is fixedly attached to the shutter member 23 in a rotating state, and the attachment end portion 30A is formed in an oval shape in cross section so that the shutter member 23 is formed. Is attached to a rotation stop hole 26A formed in the pin mounting cylinder 26 in a state of being rotated. On the other hand, the upper end side of the pin member 30 is connected to an actuator (not shown) such as an electric motor.

  The damping force adjusting valve 22 configured as described above is configured such that the shutter member 23 is moved into the shutter insertion hole 10 </ b> C via the pin member 30 by an actuator provided on the protruding end side (the upper side in the axial direction) of the rod member 8. Rotate. As a result, the first shutter port 27 of the shutter member 23 communicates with and is blocked from the guide port 10E of the guide member 10. At the same time, the second shutter port 28 of the shutter member 23 is communicated with and blocked from the guide port 10F of the guide member 10. At this time, the damping force adjusting valve 22 generates a damping force corresponding to the passage area by the shutter ports 27 and 28 and the like.

  As shown in FIG. 2, a bush 31 that also serves as a seal member is provided between the guide member 10 and the pin member 30, and the bush 31 is a lid portion 25 of the shutter member 23 in the shutter insertion hole 10 </ b> C. It is arranged at a position where it abuts via the washer 32. The bush 31 supports the pin member 30 so as to be rotatable within the guide member 10 and compensates for a smooth rotation operation between the pin member 30 and the shutter member 23.

  A cylindrical body 33 is provided in the shutter insertion hole 10 </ b> C of the guide member 10 so as to be positioned below the shutter member 23. The cylindrical body 33 constitutes a positioning member that positions the shutter member 23 in the axial direction with a washer 32 (bush 31) provided on the upper side of the shutter member 23.

  As shown in FIG. 1, the rod member 8 of the piston rod 7 is provided with a rebound stopper 35 with a spring 34 interposed between the rod member 8 and the joint member 9. The rebound stopper 35 is provided so as to be movable along the outer peripheral surface of the rod member 8 together with the buffer rubber 36. That is, when the piston rod 7 extends greatly, the rebound stopper 35 abuts against the lower surface of the rod guide 3 via the buffer rubber 36, and the spring 34 is bent and deformed in the compression direction so as to buffer the impact at this time. It has become.

  The damping force adjusting type hydraulic shock absorber according to the present embodiment has the above-described configuration. Next, the operation thereof will be described.

  When the damping force adjusting hydraulic shock absorber is mounted on the vehicle, the upper end side of the rod member 8 is attached to the vehicle body side of the vehicle, and the attachment eye 37 (see FIG. 1) side provided on the bottom cap 2 is attached to the wheel side. When the vehicle travels, when upward and downward vibrations are generated due to road surface unevenness, the piston rod 7 is displaced from the cylinder 1 so as to expand and contract, and the contraction side damping valve 13, the extension side damping valve 14 and the damping force are displaced. A damping force can be generated by the regulating valve 22 and the like, and the vibration of the vehicle can be buffered.

  That is, in the reduction stroke of the piston rod 7, the piston rod 7 enters the cylinder 1, and the inside of the bottom side oil chamber B becomes higher than the rod side oil chamber A. Flows from the oil passage 6A of the piston 6 into the rod-side oil chamber A through the annular recess 6C and the compression-side damping valve 13 (notch 13A). Further, the oil liquid that has flowed into the bypass passage 21 (in the shutter insertion hole 10C of the guide member 10) from the bottom side oil chamber B is, for example, the second shutter port 28 of the shutter member 23, the guide port 10F of the guide member 10, and the cylinder. It flows into the intermediate chamber D in the cap member 20 through the notch 19A of the shaped spacer 19, and from the oil passage 15A of the sub-piston 15 to the rod side through the annular recess 15C and the reduction-side disk valve 16 (including the notch). It circulates in the oil chamber A.

  On the other hand, in the extension stroke of the piston rod 7, the piston 6 is slid upward in the cylinder 1, and the rod-side oil chamber A becomes higher in pressure than the bottom-side oil chamber B. The oil liquid flows from the oil passage 6B of the piston 6 into the bottom side oil chamber B through the annular recess 6E and the extension side damping valve 14 (notch 14A). Further, the oil liquid flowing from the rod-side oil chamber A into the oil passage 15B, the annular recess 15E, and the recess 15G (that is, the bypass passage 21) of the sub-piston 15 passes through the guide port 10E of the guide member 10 and the shutter member 23. It flows into the shutter insertion hole 10C via the first shutter port 27 and flows into the bottom side oil chamber B from the opening end 10D side.

  Here, when the shutter member 23 of the damping force adjusting valve 22 is rotated to connect the first shutter port 27 to the guide port 10E of the guide member 10, the oil liquid flowing through the first shutter port 27 A damping force corresponding to the passage area can be generated.

  By the way, when the piston rod 7 is suddenly extended, the oil liquid cannot be circulated only by the passage formed by the guide port 10E of the guide member 10 and the first shutter port 27 of the shutter member 23. In this case, the oil in the rod side oil chamber A opens the extension side disk valve 17 of the sub piston 15 and flows into the intermediate chamber D, and the notch 19A of the cylindrical spacer 19 and the guide member 10 guide. It flows into the shutter insertion hole 10C through the port 10F and the second shutter port 28 of the shutter member 23, and flows into the bottom side oil chamber B from the opening end 10D side.

  Thus, when the oil liquid flows through the passage formed by the guide port 10F of the guide member 10 and the second shutter port 28 of the shutter member 23, the oil liquid circulates vigorously. In particular, as shown in FIG. 8, when the narrow portion 28A to the wide inclined portion 28B of the second shutter port 28 are arranged at the position of the guide port 10F, the guide port 10F is narrowed by the second shutter port 28. The area of the passage at this time is small, and the oil liquid circulates in the passage at high speed in the direction of arrow E.

  When oil liquid circulates through the passage at high speed, the pressure in the vicinity of the passage decreases, so that a fluid force due to low pressure acts on the inner surface of the passage, that is, the inner surface 28D of the second shutter port 28. In this case, when a low pressure acts on the inner surface 28D at the position of the widening inclined portion 28B, the fluid force due to the low pressure tends to rotate the shutter member 23 in the direction in which the passage becomes smaller, that is, in the direction indicated by the arrow F. For this reason, the accuracy of positioning control of the shutter member 23 by the actuator is deteriorated.

  However, according to the present embodiment, the thickness of the portion of the side wall 24 of the shutter member 23 where the second shutter port 28 is formed is thinner than the thickness of the other portions. Specifically, by forming a recessed portion 29 in a portion where the second shutter port 28 is formed in the inner peripheral surface 24B of the side wall 24, the inner peripheral surface 24B is recessed to the outer diameter side only by this portion. A thin portion 24E (thickness size t2) thinner than the surrounding thick portion 24D (thickness size t1) is formed.

  Therefore, the area of the inner surface 28D at this position can be reduced by setting the thinned portion 24E at the position of the widened inclined portion 28B of the second shutter port 28. Thereby, the force by which the fluid force due to the low pressure tries to rotate the shutter member 23 in the direction indicated by the arrow F can be kept small.

  As a result, the shutter member 23 for adjusting the damping force can be fixed at a predetermined rotational position according to the control situation, so that the accuracy of positioning control of the shutter member 23 can be improved. In addition, since the shutter member 23 has only a part of the side wall 24 as the thin part 24E and most of the part as the thick part 24D, sufficient strength can be maintained.

  Further, by providing a recessed portion 29 so as to recessed the inner peripheral surface 24B of the side wall 24 of the shutter member 23, a thin-walled portion 24E having a thin thickness is formed at this position. Thereby, it can arrange | position so that the guide port 10F of the guide member 10 and the 2nd shutter port 28 of the shutter member 23 may closely_contact | adhere, and can distribute | circulate an oil liquid smoothly.

  Furthermore, the thin portion 24E and the recessed portion 29 formed by thinning a part of the side wall 24 of the shutter member 23 are formed to extend in the axial direction so as to reach the opening end 24C of the side wall 24. Thus, even when the shutter member 23 is manufactured using a molding process, the molding die (core) can be extracted from the opening end 24C. Therefore, the shutter member 23 is manufactured at a low cost using this molding process. Can do.

  In the embodiment, two guide ports 10E and 10F are provided on the side wall 10A of the guide member 10 and two shutter ports 27 and 28 are provided on the side wall 24 of the shutter member 23 correspondingly. The case has been described as an example. However, the present invention is not limited to this, and for example, three or four or more guide ports 10E and 10F and shutter ports 27 and 28 may be provided.

  In the embodiment, the case where the outer shell of the single cylinder type damping force adjusting hydraulic shock absorber is formed using the cylindrical cylinder 1 has been described as an example. However, the present invention is not limited to this. For example, the present invention may be applied to a double-cylinder damping force adjusting shock absorber including an outer cylinder and an inner cylinder.

  On the other hand, in the embodiment, the case where an actuator such as an electric motor that rotates the pin member 30 is provided on the protruding end side (the upper side in the axial direction) of the rod member 8 has been described as an example. However, the present invention is not limited to this, and an actuator such as an electric motor that rotates the pin member of the damping force adjusting valve may be provided inside the cylinder (for example, in the piston rod). In this case, it is possible to improve the mountability of the damping force adjustment type shock absorber to the vehicle, and the actuator is not protruded and mounted in the engine room, which is space-saving and safe. Further, the pin member of the damping force adjusting valve does not necessarily need to be rotated using an actuator such as an electric motor, and may be configured to rotate the shutter member via the pin member by manual operation, for example.

  Furthermore, in the embodiment, the damping force adjusting hydraulic shock absorber as a damping force adjusting shock absorber provided in a vehicle such as an automobile has been described as an example. However, the present invention is not limited to this. For example, the present invention can also be applied to a damping force adjustment type shock absorber used for various machines, buildings, and the like that serve as vibration sources.

  Next, the invention included in the above embodiment will be described. That is, in the present invention, the shutter member is formed as a cylindrical body whose outer peripheral surface of the side wall is rotatably inserted into the guide member, and the portion of the inner peripheral surface of the side wall where the shutter port is formed is outside. It is set as the structure which forms thinly by making it dent in the diameter side. Thereby, it can arrange | position so that the guide port of a guide member and the shutter port of a shutter member may closely_contact | adhere, and an oil liquid can be distribute | circulated smoothly by the channel | path by a guide port and a shutter port.

  Further, according to the present invention, the thin portion formed by thinning a part of the side wall of the shutter member is formed so as to reach the opening end in the axial direction of the shutter member. Accordingly, since a molding die (core) can be taken out from the inside of the shutter member, the shutter member can be manufactured at low cost by using molding.

1 cylinder 6 piston 6A, 6B oil passage (main passage)
7 piston rod 10 guide member 10A, 24 side wall 10B pin insertion hole 10C shutter insertion hole 10D open end 10E, 10F guide port 13 contraction side damping valve 14 extension side damping valve 15 sub piston 16 reduction side disk valve 17 extension side disk valve 20 Cap member 21 Bypass passage 22 Damping force adjusting valve 23 Shutter member 24A Outer peripheral surface 24B Inner peripheral surface 24C Open end 24D Thick part 24E Thin part 25 Lid part 26 Pin mounting cylinder 27 First shutter port 28 Second shutter port 28A Narrow Width part 28B Widening inclined part 28C Wide part 28D Inner surface 29 Recessed part 30 Pin member A Rod side oil chamber (cylinder chamber)
B Bottom side oil chamber (cylinder chamber)
t1 Thickness of thick part t2 Thickness of thin part

Claims (2)

Two cylinder chambers are communicated with each other by a main passage and a bypass passage, and a damping force is generated by controlling a flow of fluid generated in the main passage and the bypass passage by sliding of a piston in the cylinder. In the damping force adjustment type shock absorber that can adjust the damping force by adjusting the damping force with the damping force adjustment valve,
The damping force adjusting valve includes a cylindrical guide member having a guide port on a side wall, and a shutter member having a shutter port that is rotatably fitted in the guide member and faces the guide port on the side wall.
The shutter member is formed as a cylindrical body in which an outer peripheral surface of the side wall is rotatably fitted in the guide member;
Of the side wall of the shutter member, the thickness of the part where the shutter port is formed is formed thinner than the thickness of the other part ,
Wherein of the inner circumferential surface of the side wall, the damping force adjustable shock absorber ing a structure for forming thin wall thickness by recessed a portion the shutter port is formed on the outer diameter side. 2. The damping force adjusting type shock absorber according to claim 1, wherein a thin portion formed by thinning a part of a side wall of the shutter member is formed so as to reach an opening end in an axial direction of the shutter member.

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