AU2017101642A4

AU2017101642A4 - Shock Absorber With Hydraulic Bump Stop

Info

Publication number: AU2017101642A4
Application number: AU2017101642A
Authority: AU
Inventors: Thongchai EIAMWATTANASIN; James Marshal RENOU; Nguyen Khoi TA; Simon Christopher WRAITH
Original assignee: Aeroklas Asia Pacific Group Pty Ltd; Profender Co Ltd
Current assignee: Aeroklas Asia Pacific Group Pty Ltd; Profender Co Ltd
Priority date: 2017-08-10
Filing date: 2017-11-23
Publication date: 2018-01-04
Anticipated expiration: 2025-11-23
Also published as: CN209146204U; TWM575838U

Abstract

A shock absorber with a hydraulic bump stop comprises a cylinder filled with damping medium. The cylinder has two end portions, i.e., the first end portion through which a piston rod is inserted and the second end portion attached to the second cap. The interior volume of 5 the cylinder is partitioned into three chambers, i.e., the first chamber, the second chamber, and the third chamber. The capacity of each chamber depends on the positions of the first piston, second piston, and the third piston, respectively. The piston rod extends through the first chamber. The first piston is attached to the end portion of the piston rod. The second cap includes two end portions, i.e., the first end portion attached to the cylinder and the second end 10 portion attached to a part of the vehicle. The first end portion of the second cap is provided with a recess. The fourth chamber is located in the recess and includes two springs. FIG. 5 30 33 44> 62 45 63 - 65 FIG. 4 44 4- 343 35 G ,-64

Description

SHOCK ABSORBER WITH HYDRAULIC BUMP STOP FIELD OF THE INVENTION

The present invention relates to a shock absorber, especially, a shock absorber with a hydraulic bump stop.

BACKGROUND OF THE RELATED ART A shock absorber in a suspension system acts as a vibration damper in the suspension system. An example of such shock absorber has previously been invented. For example, the United States Patent No. 6,814,193 by Grundei disclosed a shock absorber with a hydraulic pressure stop comprising a cylinder filled with damping medium; a piston rod movable in and out of the cylinder; a first piston; a second piston; a transfer spring; a disk valve, a first working space; a second working space; and a third working space. It can be seen that the second piston disclosed in the United States Patent No. 6,814,193 is movable in the longitudinal direction of the cylinder without any blockage. Such feature is thus different from the present invention.

SUMMARY OF THE INVENTION

The present invention provides a shock absorber with a hydraulic bump stop comprising: a piston rod guide attached to a cylinder at a position proximal to the first end portion of the cylinder; a cylinder filled with damping medium, the cylinder having two end portions, i.e., the first end portion through which a piston rod is inserted and the second end portion attached to the second cap, the interior volume of the cylinder is partitioned into three chambers, i.e., the first chamber located between the piston rod guide and the first piston; the second chamber located between the first piston and the second piston; and the third chamber located between the second piston and the third piston, the capacity of each chamber depending on the positions of the first piston, second piston, and the third piston, respectively; a piston rod movable in and out of the cylinder, the piston rod extending through the first chamber; a first cap attached to the first end portion of the cylinder; a first piston attached to an end portion of the piston rod, the first piston being movable in the longitudinal direction of the cylinder, the first piston partitioning the interior volume of the cylinder and having a plurality of holes through which the damping medium flows; a second piston located at a distance from the first piston, the second piston having the same diameter as that of the first piston, the second piston partitioning the interior volume of the cylinder and having a plurality of holes through which the damping medium flows; characterized by further including: a second cap having two end portions, i.e., the first end portion attached to the second end portion of the cylinder and the second end portion to be attached to a part of the vehicle, the first end portion of the second cap including an edge and a recess adjacent to the edge, the recess having a certain depth to the first shoulder, a further certain depth to the second shoulder and an aperture being located adjacent to the second shoulder, the aperture being elongated to the lateral side of the second cap; a fourth chamber inside the recess, the fourth chamber located between the third piston and the second shoulder of the recess, the fourth chamber is occupied by the second spring; a third piston located at a distance from the second piston, the third piston having the same diameter as that of the recess, the third piston having a plurality of holes through which the damping medium flows; a first spring provided between the second piston and the third piston; and a second spring provided between the third piston and the second shoulder;

An objective of the present invention is to provide a shock absorber with a hydraulic bump stop to provide elevated damping when the shock absorber is at higher displacement in the compression stroke. The displacement is damped under both small strokes and large strokes. Displacement damping of the suspension system results in the comfort of the driver and the passengers in the vehicle.

Another objective of the present invention is to provide a shock absorber with a hydraulic bump stop comprising a third piston for use in providing high pressure while the shock absorber is at higher displacement in the compression stroke, the third piston moving in the longitudinal direction of the cylinder and disposed inside the recess of the second cap, the third piston capable of being designed to work effectively with the working conditions of various vehicles due to the possibility to control the stroke of the third piston to achieve the proper length with the annular spring blocking the displacement of the third piston.

Other objectives will become apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a partial sectional view showing a shock absorber with a hydraulic bump stop according to the present invention;

Fig. 2 is a top perspective view and an exploded view of a shock absorber with a hydraulic bump stop according to the present invention;

Fig. 3 is a bottom perspective view showing the third piston;

Fig. 4 is a perspective view and a sectional view of the second cap;

Fig. 5 is an enlarged view of the elliptical section defined by the dash-dotted line in Fig. l;

Fig. 6 is a partial sectional view showing the operation in the compression stroke while the first piston is moving toward the second piston;

Fig. 7 is a partial sectional view showing the compression stroke when the first piston comes into contact with the second piston;

Fig. 8 is a partial sectional view showing the operation in the compression stroke while the first piston, the second piston, and the third piston are moving concurrently;

Fig. 9 is a partial sectional view showing the operation in the compression stroke when the third piston presses against the ring;

Fig. 10 is a partial sectional view showing the compression stroke when the second piston comes into contact with the edge of the second cap;

Fig. 11 is a partial sectional view showing the operation during the rebound stroke while the first piston and the second piston are moving away from the third piston;

Fig. 12 is a partial sectional view showing the operation during the rebound stroke while the third piston is moving away from the ring;

Fig. 13 is a partial sectional view showing the operation during the rebound stroke when the third piston comes into contact with the annular spring;

Fig. 14 is a graph showing the force with respect to the displacement of the shock absorber with a hydraulic bump stop according to the present invention during the normal operation;

Fig. 15 is a graph showing the force with respect to the displacement of the shock absorber with a hydraulic bump stop according to the present invention while the hydraulic bump stop is operating at the high amount of elevated damping;

Fig. 16 is a graph showing the force with respect to the displacement of the shock absorber with a hydraulic bump stop according to the present invention while the hydraulic bump stop is operating at the lower amount of elevated damping than that in Fig. 15;

Fig. 17 is a graph showing the force with respect to the displacement of the shock absorber with a hydraulic bump stop according to the present invention operating in the normal operation overlaid with the operation of the hydraulic bump stop. DETAILED DESCRIPTION OF THE PRESENT INVENTION The present invention will be described in the following content with reference to the drawings. Each drawing includes numbers designating various parts. The same numbers shown in the drawings refer to the same parts.

Figs. 1 to 5 show the embodiments and the components of the shock absorber with a hydraulic bump stop 30 according to the present invention comprising: a piston rod guide 67 attached to a cylinder 32 at a position proximal to the first end portion of the cylinder 32; a cylinder 32 filled with damping medium, for example, hydraulic fluid, the cylinder having two end portions, i.e., the first end portion through which a piston rod 34 is inserted and the second end portion attached to the second cap 33, the interior volume of the cylinder is partitioned into three chambers, i.e., the first chamber 36 located between the piston rod guide 67 and the first piston 35; the second chamber 37 located between the first piston 35 and the second piston 38; and the third chamber 39 located between the second piston 38 and the third piston 41, the capacity of the respective chamber depending on the positions of the first piston 35, second piston 38, and the third piston 41; a piston rod 34 movable in and out of the cylinder, the piston rod 34 protruding through the first chamber 36; a first cap 31 attached to the first end portion of the cylinder 32; a first piston 35 attached to an end portion of the piston rod 34, the first piston 35 being movable in the longitudinal direction of the cylinder, the first piston partitioning the interior volume of the cylinder and having a plurality of holes through which the damping medium flows; a second piston 38 located at a distance from the first piston, the second piston having the same diameter as that of the first piston, the second piston partitioning the interior volume of the cylinder and having a plurality of holes through which the damping medium flows; a second cap 33 having two end portions, i.e., the first end portion attached to the second end portion of the cylinder 32 and the second end portion to be attached to a part of the vehicle, the first end portion of the second cap including an edge 70 and a recess 68 adjacent to the edge 70, the recess 68 having a certain depth to the first shoulder 62, a further certain depth to the second shoulder 63, and an aperture 45 being located adjacent to the second shoulder 63, the aperture 45 being elongated to the lateral side of the second cap; a fourth chamber 42 inside the recess 68, the fourth chamber located between the third piston 41 and the second shoulder 63 of the recess 68, the fourth chamber is occupied by the second spring 43; a third piston 41 located at a distance from the second piston, the third piston having the same diameter as that of the recess 68, the third piston having a plurality of holes through which the damping medium flows; a first spring 40 provided between the second piston 38 and the third piston 41; and a second spring 43 provided between the third piston 41 and the second shoulder 63; wherein the first spring 40 includes two end portions, i.e., the first end portion to be attached to the second piston 38 and the second end portion to be attached to the third piston 41, the first end portion 55 being linear, the first end portion 55 being inserted into the straight hole 60 at the flange 58 of the second piston 38, the second end portion 56 being linear,, the second end portion 56 being inserted into the straight hole 61 at the protrusion 52 of the third piston 41; wherein the length of the second spring 43 under no pressure is the length L2 (Fig. 2), the length L2 being longer than the length LI (Fig. 5) representing the clearance between the third piston 41 and the second shoulder 63, the length LI being the length of the second spring 43 under a certain pressure. As a result, the second spring 43 pushes the third piston 41 to press against the annular spring 64.

Fig. 2 shows the protrusion 51 protruding from the central portion of the third piston 41, the end portion of the second spring 43 properly engages with the protrusion 51.

Furthermore, Fig. 2 shows that the flange 58 extending from the edge of the hole 57 of the second piston 38, the first end portion of the first spring 40 being able to properly engage with the flange 58. Also, the flange 58 includes a straight hole 60 through the flange 58.

Furthermore, Fig. 3 shows the protrusion 52 protruding from the central portion of the third piston 41, the second end portion of the first spring 40 properly engages with the protrusion 52. Also, the protrusion 52 includes a straight hole 61.

Furthermore, Fig. 5 shows the length L3 which is the length of the first spring 40 under no pressure.

Furthermore, the present invention provides annular spring 64. The annular spring 64 is fastened into the groove 65 of the recess 68. The annular spring 64 acts in blocking the displacement of the third piston 41.

The present invention also provides the ring 44 made of an elastic material, for example, nylon 66. The ring 44 is press fit mounted on the first shoulder 62 in the recess 68. In the position that generates maximum damping force, the third piston 41 comes into contact with and presses against the ring 44 and thus closes all of the holes 54 along the circumference of the center of the third piston 41, except for the hole 53 (or holes 53) at the central portion of the third piston which is not closed.

The present invention also provides the hose 47 located between the aperture 45 of the second cap 33 and the remote reservoir 48.

The present invention also provides a compression adjustment knob 49 adjacent to the remote reservoir 48.

The present invention also provides a rebound adjustment knob 50 at the base 46 attached at the end portion of the piston rod 34.

It additionally comprises a ring 69 made of an elastic material, for example, nylon 66. The ring 69 is attached to the inner edge of the hole 57 at the central portion of the second piston 38. When the first piston 35 comes into contact with the ring 69, the hole 57 at the central portion of the second piston is thus closed.

Fig. 6 shows the operation in the compression stroke. It can be seen that the piston rod 34 starts to approach the cylinder. The damping medium is caused to flow from the second chamber 37 through the holes of the first piston 35 to the first chamber 36 in the direction of the arrows.

Fig. 7 shows the operation in the compression stroke. It can be seen that the piston rod 34 moves closer to the cylinder. At this time, the first piston 35 comes into contact with the ring 69 of the second piston 38 and thus closes the hole 57. Therefore, the damping medium is allowed to flow from the second chamber 37 through the holes of the first piston 35 to the first chamber 36 in the direction of the arrows.

Fig. 8 shows the operation in the compression stroke. It can be seen that the piston rod 34 moves even closer and thus allows the first piston, the second piston, and the third piston to move together. There is damping medium flows from the fourth chamber 42 through the hole 53 and the holes 54 of the third piston 41 to the third chamber 39 and there is damping medium flows from the third chamber 39 through the holes 59 of the second piston 38 to the second chamber 37 and through the holes of the first piston 35 to the first chamber 36 in the direction of the arrows.

Fig. 9 shows the operation in the compression stroke. It can be seen that the piston rod 34 moves even closer. It thus causes the third piston 41 to press against the ring 44 and causes the second piston 38 to press against the first spring 40 until it collapses. There is damping medium flows from the third chamber 39 through the holes 59 of the second piston 38 to the second chamber 37 and through the holes of the first piston 35 to the first chamber 36 and part of the damping medium flows from the third chamber 39 through the hole 53 of the third piston 41 to the fourth chamber 42 and flows further in the direction toward the remote reservoir 48 in the direction of the arrows.

Fig. 10 shows the operation when the second piston 38 contacts the edge 70 of the second cap 33 where it receives maximum pressure.

Fig. 11 shows the operation in the rebound stroke. It can be seen that the piston rod 34 starts to move away from the cylinder and thus moves the first piston 35 and the second piston 38 away from the third piston 41. The damping medium is caused to flow from the first chamber 36 through the holes of the first piston 35 to the second chamber 37 and the damping medium flows from the second chamber 37 through the holes 59 of the second piston to the third chamber 39 and part of the damping medium flows from the remote reservoir 48 to the fourth chamber 42 and flows from the fourth chamber 42 through the hole 53 of the third piston 41 to the third chamber 39 in the direction of the arrows.

Fig. 12 shows the operation in the rebound stroke where the piston rod 34 moves farther away from the cylinder and thus moves the third piston 41 away from the ring 44 while the first piston, the second piston, and the third piston move together. The damping medium is caused to flow from the first chamber 36 through the hole of the first piston 35 to the second chamber 37. The damping medium flows from the second chamber 37 through the holes 59 of the second piston to the third chamber 39 and the damping medium flows from the third chamber 39 through the hole 53 and holes 54 of the third piston to the fourth chamber 42 in the direction of the arrows.

Fig. 13 shows the operation in the rebound stroke where the piston rod 34 moves even farther away from the cylinder. The third piston 41 is caused to come into contact with the annular spring 64. The annular spring 64 acts in blocking the displacement of the third piston 41. At this time, the second piston 38 has moved away from the third piston 41 at the farthest distance and the damping medium flows from the first chamber 36 through the holes of the first piston 35 to the second chamber 37 in the direction of the arrows.

Fig. 14 is a graph showing relationship between the force (Newton) acted on the piston rod with respect to the displacement (mm) of the piston rod. This graph is plotted based on the shock absorber dynamometer. This figure shows the graph during the normal operation. That is, the first piston moves in and out of the cylinder while the first piston does not contact the second piston.

Fig. 15 is a graph showing relationship between the force acted on the piston rod with respect to the displacement of the piston rod. This figure shows the graph when the hydraulic bump stop operates at the extremely high amount of impact. It can be seen in the figure that the amount of forces slightly exceeds 7,000 Newton since the third piston 41 presses on the ring 44 and the second piston 38 approaches the edge 70.

Fig. 16 is a graph showing relationship between the force acted on the piston rod with respect to the displacement of the piston rod. This figure shows the graph when the hydraulic bump stop operates at the lower amount of impact than that of Fig. 15. It can be seen in this Fig. 16 that the amount of forces slightly exceeds 3,000 Newton since the first spring 40 pushes the third piston 41 away from the annular spring 64 until the third piston 41 moves close to the ring 44.

Fig. 17 is a graph showing relationship between the force acted on the piston rod with respect to the displacement of the piston rod. This figure shows the graph during the normal operation overlaid with the operation of the hydraulic bump stop. It can be seen that the hydraulic bump stop operates in the compression stroke when the piston rod displaces in the range of 12 mm to 25 mm. The two curves will almost overlap beyond this range.

Since the present invention provides a shock absorber with a hydraulic bump stop to damp the displacement of the suspension system. The displacement is damped under both small strokes and large strokes. Under small displacement strokes, the first piston moves in and out of the cylinder, where the first piston does not come into contact with the second piston. As a result, the damping force is generated in the proper amount and provides the driver and the passengers in the vehicle with comfort. On the other hand, while driving under large compression displacement strokes, the first piston starts to push the second piston and if the impact becomes higher, the third piston will push the ring to properly distribute the impact and continue to provide the driver and the passengers in the vehicle with comfort.

Also, since the present invention provides a shock absorber with a hydraulic bump stop including the third piston with a plurality of holes, some of which are closed during the shock absorber is moving further in the compression stroke resulting in the damping force is generated in the higher amount. As a result, it is possible to absorb high amount of impact and to design the third piston to effectively operate in correspondence with the working conditions of various types of vehicles. This is due to the fact that it is possible to control the stroke of the third piston to achieve the suitable length using the annular spring in blocking the displacement of the third piston.

Claims

1. A shock absorber with a hydraulic bump stop (30) comprising: a piston rod guide (67) attached to a cylinder(32) at a position proximal to the first end portion of the cylinder (32); a cylinder (32) filled with damping medium, the cylinder (32) having two end portions, i.e., the first end portion through which a piston rod (34) is inserted and the second end portion attached to the second cap (33), the interior volume of the cylinder is partitioned into three chambers, i.e., the first chamber (36) located between the piston rod guide (67) and the first piston (35); the second chamber (37) located between the first piston (35) and the second piston (38); and the third chamber (39) located between the second piston (38) and the third piston (41), the capacity of each chamber depending on the positions of the first piston (35), second piston (38), and the third piston (41), respectively; a piston rod (34) movable in and out of the cylinder, the piston rod (34) extending through the first chamber (36); a first cap (31) attached to the first end portion of the cylinder (32); a first piston (35) attached to an end portion of the piston rod (34), the first piston (35) being movable in the longitudinal direction of the cylinder, the first piston partitioning the interior volume of the cylinder and having a plurality of holes through which the damping medium flows; a second piston (38) located at a distance from the first piston, the second piston having the same diameter as that of the first piston, the second piston partitioning the interior volume of the cylinder and having a plurality of holes through which the damping medium flows; characterized by further including: a second cap (33) having two end portions, i.e., the first end portion attached to the second end portion of the cylinder (32) and the second end portion to be attached to a part of the vehicle, the first end portion of the second cap including an edge (70) and a recess (68) adjacent to the edge (70), the recess (68) having a certain depth to the first shoulder (62), a further certain depth to the second shoulder (63) and an aperture (45) being located adjacent to the second shoulder (63), the aperture (45) being elongated to the lateral side of the second cap (33); a fourth chamber (42) inside the recess (68), the fourth chamber located between the third piston (41) and the second shoulder (63) of the recess (68), the fourth chamber is occupied by the second spring (43); a third piston (41) located at a distance from the second piston, the third piston having the same diameter as that of the recess (68), the third piston having a plurality of holes through which the damping medium flows; a first spring (40) provided between the second piston (38) and the third piston (41); and a second spring (43) provided between the third piston (41) and the second shoulder (63).

2. The shock absorber with a hydraulic bump stop according to claim 1, wherein the first spring (40) includes two end portions, i.e., the first end portion to be attached to the second piston (38) and the second end portion to be attached to the third piston (41)

3. The shock absorber with a hydraulic bump stop according to claim 2, wherein the first end portion (55) being linear, the first end portion (55) being inserted into the straight hole (60) at the flange (58) of the second piston (38), the second end portion (56) being linear, the second end portion (56) being inserted into the straight hole (61) at the protrusion (52) of the third piston (41).

4. The shock absorber with a hydraulic bump stop according to claim 1, wherein the length (L2) of the second spring (43) under no pressure is longer than the length (LI) of the distance between the third piston (41) and the second shoulder (63).

5. The shock absorber with a hydraulic bump stop according to claim 1, further including an annular spring (64), the annular spring (64) is fastened into the groove (65) of the recess (68), the annular spring (64) acts in blocking the displacement of the third piston (41).

6. The shock absorber with a hydraulic bump stop according to claim 1, further including the ring (44) made of an elastic material, the ring (44) is mounted on the first shoulder (62) in the recess (68), in the position that generates maximum damping force, the third piston (41) comes into contact with and presses against the ring (44) and thus closes all of the holes (54) along the circumference of the center of the third piston (41), except for the hole/s (53) at the central portion of the third piston which is not closed.

7. The shock absorber with a hydraulic bump stop according to claim 1, further including the hose (47) located between the aperture (45) of the second cap (33) and the remote reservoir (48).

8. The shock absorber with a hydraulic bump stop according to claim 1, further including a compression adjustment knob (49) adjacent to the remote reservoir (48).

9. The shock absorber with a hydraulic bump stop according to claim 1, further including a rebound adjustment knob (50) at the base (46) attached at the end portion of the piston rod (34).

10. The shock absorber with a hydraulic bump stop according to claim 1, further including a ring (69) made of an elastic material, the ring (69) being attached to the inner edge of the hole (57) at the central portion of the second piston (38). When the first piston (35) comes into contact with the ring (69), the hole (57) at the central portion of the second piston is thus closed.