Hydraulic damping device

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a damping device, and more particularly to an adjustable hydraulic damping device with a simplified structure.

2. Description of Related Art

A hydraulic damping device is used as a shock-absorbing device on a bicycle or a flow controller in a flow discharging system. The conventional hydraulic damping device has an adjusting device for adjusting the damping effect provided by the damping device. However, the conventional hydraulic damping device with an adjusting device has a complex structure, and the cost for manufacturing the conventional damping device is excessive.

The main objective of the invention is to provide a hydraulic damping device with a simplified structure. A hydraulic damping device has a cylinder, a rod, a piston, a first biasing member, a seal and a second biasing member. The rod moveably extends into the cylinder. The piston is securely attached to the rod to divide the cylinder into two chambers. The piston has multiple first channels and multiple second channels communicating with the chambers, wherein each first channel has a diameter larger than that of each second channel. The seal is moveably mounted on the rod and abuts against the piston to close the first channels in the piston. Accordingly, the hydraulic damping device has a capability of adjusting the damping effect and has a simplified structure.

IN THE DRAWINGS

<ul id="ul0001" list-style="none" compact="compact"><li>Fig. 1 is an exploded perspective view of a first embodiment of a hydraulic damping device in accordance with the present invention;</li><li>Fig. 2 is a side plan view in partial cross section of the first embodiment of the hydraulic damping device in Fig. 1;</li><li>Fig. 3 is an operational side plan view in partial cross section of the first embodiment of the hydraulic damping device in Fig. 1;</li><li>Fig. 4 is a side plan view in partial cross section of the first embodiment of the hydraulic damping device in Fig. 1 showing the feedback channel in the lining;</li><li>Fig. 5 is a side plan view in partial cross section of a second embodiment of a hydraulic damping device in accordance with the present invention;</li><li>Fig. 6 is a side plan view in partial cross section of a third embodiment of a hydraulic damping device in accordance with the present invention;</li><li>Fig. 7 is a side plan view in partial cross section of a fourth embodiment of a hydraulic damping device in accordance with the present invention;</li><li>Fig. 8 is a side plan view in partial cross section of a fifth embodiment of a hydraulic damping device in accordance with the present invention; and</li><li>Fig. 9 is a side plan view in partial cross section of a flow controller with the first embodiment of the hydraulic damping device in Fig. 1.</li></ul>

With reference to Figs. 1 and 2, a hydraulic damping device in accordance with the present invention comprises a cylinder (10), a rod (20), a piston (21), a first biasing member (22), a seal (26) and a second biasing member (24). The cylinder (10) has a space (11), a top end (122) and a bottom end (12).

A top cap (14) with an outer thread (144) is screwed with the top end (122), and a bottom cap (13) with an outer thread (134) is screwed with the bottom end (12). A central hole (132) is defined through the bottom cap (13). An annular recess (136) is defined in an inner surface defining a central hole (132). An O-ring (138) is received in the recess (136). Working fluid is contained in the space (11) at an original pressure.

The rod (20) moveably extends through central hole (132) and into the cylinder (10). A central hole (142) is defined through the top cap (14). An annular recess (146) is defined in the inner surface of central hole (142). An O-ring (148) is received in the recess (146). The rod (20) extends through the central hole (142) and out from the top end (122). The O-rings (138,148) can provide excellent sealing effect to the rod (20).

The piston (21) is securely attached to the rod (20) and is received in the cylinder (10) to divide the space (11) into a first chamber (112) and a second chamber (114). A central hole (211) is defined through the piston (21) for the rod (20) extending through the central hole (211). A threaded pin (212) is screwed into the piston (21) and has a free end abutting against the rod (20).

The piston (21) has multiple first channels (215) and second channels (216) communicating with the first chamber (112) and the second chamber (114). The first channels (215) are co-axially arranged around the central hole (211), and the second channels (216) are co-axially arranged between the outer periphery of the piston (21) and the first channels (215). Each first channel (215) has a diameter much larger than that of each second channel (216). An annular recess (213) is defined in the outer surface of the piston (21). An O-ring (214) is received in the annular recess (213).

A tubular lining (16) is mounted in the cylinder (10) and abuts the O-ring (214). A feedback channel (17) is longitudinally defined in the inner surface of the lining (16) along the axial direction of the cylinder (10). The feedback channel (17) comprises a first segment (172), a second segment (174) and a third segment (176) linearly arranged from one end of the lining (16) away from the top cap (14). The width of the first segment (172) is smaller than that of the second segment (174), and the width of the second segment (174) is smaller than that of the third segment (176).

The first biasing member (22) with a resiliency is mounted around the rod (20) and is received in the first chamber (112). Two ends of the first biasing member (22) respectively abut against the top cap (14) and the piston (21).

The seal (26) is moveably mounted on the rod (20), and is received in the second chamber (114) to abut against the piston (21) and to close the first channels (215).

The second biasing member (24) with a resiliency is mounted on the rod (20) to push the seal (26) to abut against the piston (21). A pushing base (25) is moveably mounted on the rod (20) and abuts against the seal (26). An annular securing base (23) is secured to the rod (20) by a threaded pin (232). The second biasing member (24) has two ends respectively abutting against the pushing base (25) and the securing base (23). The resiliency of the second biasing member (24) is smaller than the resiliency of the first biasing member (22).

The rod (20) can be connected to a wheel of a bicycle and the cylinder (10) can be connected to the frame of the bicycle, such that the hydraulic damping device serves as a shock-absorbing device for a bicycle. With reference to Figs. 1 to 3, when a force is applied to the wheel and transmitted to the rod (20), the rod (20) will be actuated to move. The piston (21) will move with the rod (20) so that the first chamber (112) in the cylinder (10) is reduced and then the pressure in the first chamber (112) increases. The first biasing member (22) will be compressed. Because the resiliency of the second biasing member (24) is smaller than that of the first biasing member (22), the seal (26) will be pushed away from the piston (21) by the pressure in the first chamber (112). The first channels (215) will be opened, and the working fluid in the first chamber (112) will flow into the second chamber (114) through the first channels (215). With the pressure of the working fluid in the first chamber (112), a first damping effect to the shock is provided. The first biasing member (22) can provide a second damping effect to the shock. This can keep the shock from being transmitting to the bicycle frame, and an excellent shock-absorbing effect is provided.

The damping effect can be adjusted by means of changing another first biasing member (22) with a different resiliency. The structure of the damping device with an adjustable capability is simple. The cost for manufacturing the damping device is low.

When the shock is released, the piston (21) will be pushed to move back by the recoil force provided by the first biasing member (22). The pressure in the first chamber (112) will decrease and the working fluid will flow back to the first chamber (112) from the second chamber (114). When the piston (21) is in the backward stroke, the seal (26) will be pushed to abut against the piston (21) to close the first channels (215). The working fluid will flow back to first chamber (112) through the second channels (216). Because the diameter of the second channels (216) is much smaller than that of the first channels (215), the flow rate of the working fluid flowing back to the first chamber (112) is much slower than that of the working fluid flowing into the second chamber (114) while the rod (20) is in a forward stroke. The speed of the rod (20) with the piston (21) in a backward stroke will be slowed down, and this can prevent a recoil from occurring.

With reference to Figs. 2 and 4, with the feedback channel (17) in the lining (16), the working fluid can flow back to the first chamber (112) through the feedback channel (17). Because the feedback channel (17) has multiple segments (172,174,176) with different widths, the flow rates of the working fluid passing through different segments (172,174,176) are different. This can automatically adjust the flow rate of the working fluid flowing back to the first chamber (112).

With reference to Fig. 5, the rod (20) has a threaded portion (202) formed on one end far from the cylinder (10). A nut with a ring (27) is screwed with the threaded portion (202). The first biasing member (22A) is exposed from the cylinder (10) and has two ends respectively abutting against the ring (27) and the bottom cap (13).

With reference to Fig. 6, the top cap (14A) closes the top end (122) of the cylinder (10). The end of the rod (20A) extending into the cylinder (10) does not extend out from the top cap (14A), and the piston (21) is secured to the end of the rod (20A). The first biasing member (22) is received in the first chamber (112) and has two ends respectively abutting against the piston (21) and the top cap (14A). The first biasing member (22) can also provide a recoil force to the rod (20A).

With reference to Fig. 7, the first biasing member (22A) is exposed from the cylinder (10) and has two ends respectively abutting against the bottom cap (13) and the ring (27).

With reference to Fig. 8, a lower holder (18) is mounted on the end of the rod (20B) far from the cylinder (10). An upper holder (19) is mounted on the top end (122) of the cylinder (10). The first biasing member (22B) is exposed from the cylinder (10) and has two ends respectively abutting against the upper holder (19) and the lower holder (18). The lower holder (18) has a skirt (182) formed around the lower holder (18) to hold the corresponding end of the first biasing member (22B).

A buffer (40) is mounted on the top cap (15) and communicates with the space (11) in the cylinder (10). The top cap (15) has a channel (152) communicating with the space (11) in the cylinder (10). The buffer (40) comprises a housing (42), a buffer piston (44), a sealing rod (46) and a spring (48). The housing (42) is attached to the top cap (15) and has an inner space communicating with the channel (152). An opening (422) is defined in the housing (42) at one end far away from the top cap (15). The buffer piston (44) is moveably mounted in the inner space of the housing (42) to divide the inner space of the housing (42) into a first chamber communicating with the channel (152) and a second chamber communicating with the opening (422). The sealing rod (46) is moveably received in the channel (152) and has a sealing disk formed on one end of the sealing rod (46) to close a passage between the channel (152) and the first chamber in the housing (42). The other end of the sealing rod (46) extends out from the top cap (15) and is connected to a handle bar through a cable. Accordingly, when the user pulls the handle bar, the sealing rod (46) will be actuated to move in the channel (152) so as to open the passage between the channel (152) and the first chamber in the housing (42). Consequently, working fluid in the inner space (11) can flow into the first chamber in the housing (42) through the channel (152). The spring (48) is mounted around the sealing rod (46) to provide a return force to push the sealing disk on the sealing rod (46) to close the passage between the channel (152) and the first chamber in the housing (42).

With such a buffer (40), the working fluid in the space (11) of the cylinder (10) will flow into the first chamber of the housing (42) when a shock is applied to the wheel and the rod (20B) with the piston (21) is actuated to move in the space (11) toward the top cap (15). The working fluid will push the buffer piston (44) to move relative to the housing (42). When the shock is released, the working fluid will flow back to the space (11) in the body (10), and the buffer piston (44) will move backward by the environmental air pressure.

When the handle bar connected to the sealing rod (46) is released, the sealing rod (46) will move to close the passage between first chamber in the housing (42) and the channel (152) by the recoil force provided by the spring (48). Accordingly, the working fluid, especially an oil, cannot flow into the housing (42) of the buffer, such that the first chamber (112) in the body (10) is almost uncompressible. Consequently, the piston (21) will not move relative to the body (10) even when a shock is applied to the rod (20B). The damping device serves as a rigid element, such that the damping effect of the damping device can be cut off when the user needs.

With reference to Fig. 9, the damping device can be construed of a flow controller in a flow discharging system. The cylinder (10) is received in a housing (31) of a liquid-discharging device (30) with an inlet (32) and an outlet (36). One end of the rod (20) extends through a bore (33) in the housing (31) and into the inlet (32), and a valve plate (34) mounted on the end of the rod (20) is adapted to close the bore (33). The other end of the rod (20) has a ring (27) threadingly received thereon, and the first biasing member (22A) is mounted between the bottom cap (13) on the cylinder (10) and the ring (27). A push button (35) is attached to the ring (27). Consequently, when the user presses the push button (35), the rod (20) with the piston (21) will move relative to the cylinder (10), and the valve plate (34) will leave the bore (33) so as to open the bore (33). Accordingly, the fluid will be discharged from the outlet (36) through the inlet (32), the bore (33) and the housing (31). Because the damping device in accordance with the present invention has a slow backward stroke, an amount of time is needed for the plate valve (34) to move to the position where it closes the bore (33). Therefore, a desired amount of liquid will be discharged from the discharging device (30), and the damping device in accordance with the present invention can be used to control the flow rate and discharging amount of the liquid.