Patent Application
20160363184
This application is based on and claims the benefit of priority from Japanese Patent Application No 2015-118163, filed on Jun. 11, 2015, the entire contents of which are incorporated herein by reference.
Technical Field
The present invention relates to a damper.
Related Art
Dampers are used as rear cushion units for supporting rear wheels of saddled vehicles such as two-wheeled vehicles or three-wheeled vehicles. The rear cushion units include a pneumatic spring-type rear cushion unit having a gas spring for elastically supporting a vehicle body, using the elastic force of gas, as disclosed in JP 2001-501155 A,
A rear shock absorber described in JP 2001-501155 A includes an upper cylindrical member and a lower cylindrical member in cylindrical shapes telescopically slidable on each other, a piston rod connected to the upper cylindrical member to move into and out of the lower cylindrical member, a first chamber formed between the piston rod and the upper cylindrical member, a second chamber formed between overlap portions of the upper cylindrical member and the lower cylindrical member, and a compressor piston fitted on the outer periphery of the lower cylindrical member to partition the first and second chambers. The first chamber is filled with gas to function as a positive spring for biasing the rear shock absorber in an extension direction. In addition, the second chamber is filled with gas to function as a negative spring for biasing the rear shock absorber in a contraction direction.
This configuration allows the spring characteristics of the entire device to be changed by not only adjusting the pressure in the first chamber but also adjusting the pressure in the second chamber. In the rear shock absorber described in JP 2001-501155 A, a valve is provided at an end portion of the upper cylindrical member to supply and exhaust gas to and from the second chamber so that the spring characteristics can be changed.
However, when a valve for gas supply and exhaust is attached to a member surrounding a gas chamber such as a chamber as in the above conventional rear shock absorber, there is a fear that the pressure in the gas chamber cannot be adjusted. To explain in more detail, when a damper is a rear cushion unit, for example, the rear cushion unit is interposed between a frame constituting the skeleton of a vehicle body and a swing arm swingably connected to the frame for supporting a rear wheel. In particular, when the rear cushion unit is mounted to a motorized saddled vehicle, an air valve portion may be hidden by a frame or a peripheral part of a motor held on the frame, depending on the vehicle type. In this case, an air valve is inaccessible with the damper mounted to the vehicle. As a result, the adjustment of the pressure in a gas chamber becomes impossible. This trouble can occur not only in a case where a damper is a rear cushion unit.
Thus, the present invention has an object of providing a damper capable of preventing the adjustment of the pressure in a gas chamber from becoming impossible even in a mounted state.
A damper, a means to solve the problem in the present invention, includes a tube member connected to a rod and forming a gas chamber that is enlarged and reduced in capacity by relative movement of a cylinder and the rod, a bracket provided at an end portion of the rod protruding from the cylinder, a passage formed in the bracket and the rod and communicating with the gas chamber, and a gas supply and exhaust valve attached to the bracket to be provided at an end portion of the passage on one side.
Hereinafter an embodiment of the present invention will be described with reference to the drawings. The same reference numerals provided through some drawings denote the same components.
As illustrated in
As illustrated in
In the present embodiment, the rear cushion. unit R is of an inverted type with the rod 2 connected to the wheel side and the cylinder 1 connected to the vehicle body side. In the mounted state, the rod 2 of the rear cushion unit R extends downward of the cylinder 1. However, the rear cushion unit F may be of an upright type with the rod 2 connected to the vehicle body side and the cylinder 1 connected to the wheel side.
The damper body D includes the above-described cylinder 1 and rod 2, an annular rod guide 10 provided at an upper end portion of the cylinder 1 in
The cylinder 1 has a bottomed cylindrical shape. In the cylinder 1, an extension-side chamber L1 on the rod 2 side and a compression-side chamber L2 on the piston 20 side partitioned by the piston 20 are formed. In the tank 3, a liquid chamber L3 and a gas chamber G3 partitioned by the free piston 30 are formed. The compression-side chamber L2 and the liquid chamber L3 are partitioned by the base valve 11. The extension-side chamber L1 the compression-side chamber L2, and the liquid chamber L3 are filled with hydraulic oil, and the gas chamber G3 is filled with air. An air valve not shown for supplying and exhausting air to and from the gas chamber G3 is attached to the tank 3 so that the pressure in the gas chamber G3 can be adjusted.
The rod guide 10 provided at the upper end portion of the cylinder 1 in
As illustrated in
The piston 20 that partitions the interior of the cylinder 1 into the extension-side chamber L1 and the compression-side chamber L2 is formed with an extension-side flow path 20a and a compression-side flow path 20b that connect the extension-side chamber L1 and the compression-side chamber L2. An extension-side leaf valve V1 for opening and closing the outlet of the extension-side flow path 20a is placed on the lower end of the piston 20 in
The base valve 11 partitioning the interior of the cylinder 1 and the interior of the tank 3 includes, as shown by hydraulic symbols in
According to the above configuration, when the rear cushion unit R extends, the rod 2 moves upward in
Then, the pressure in the extension-side chamber L1 compressed increases, and hydraulic oil in the extension-side chamber L1 pushes open the extension-side leaf valve V1 and passes through the extension-side flow path 20a, moving to the compression-side chamber L2. An the cylinder 1, although hydraulic oil becomes short by the rod volume that has exited from the cylinder 1, the check valve V3 opens so that hydraulic oil commensurate with the shortage is supplied from the liquid chamber L3 to the compression-side chamber L2 through the suction flow path 11a. Since the extension-side leaf valve V1 provides a resistance to the flow of hydraulic oil from the extension-side chamber L1 toward the compression-side chamber L2, the pressure of the extension-side chamber L1 increases. In contrast, the compression-side chamber L2 is supplied with hydraulic oil from the liquid chamber L3, and thus has a pressure substantially equal to that in the tank 3, Therefore, a difference in pressure occurs between the extension-side chamber L1 and the compression-side chamber L2. The differential pressure is applied to the piston 20, and the damper body D exerts a damping force to suppress the extending action of the rear cushion unit R.
On the contrary, when the rear cushion unit R contracts, the rod 2 moves downward in
Then, the pressure in the compression-side chamber L2 compressed increases, and hydraulic oil in the compression-side chamber L2 pushes open the compression-side leaf valve V2 and passes through the compression-side flow path 20b, moving to the extension-side chamber L1. In the cylinder 1, although hydraulic oil becomes surplus by the rod volume that has entered. in the cylinder 1, the surplus hydraulic oil pushes open the damping valve V4 and passes through the discharge flow path 11b, being discharged from the compression-side chamber L2 to the liquid chamber L3. Thus, the compression-side leaf valve V2 and the damping valve V4 provide resistances to the flow of hydraulic oil from the compression-side chamber L2 toward the extension-side chamber L1 and the liquid chamber L3, so that the pressure of the compression-side chamber L2 increases. In contrast, the pressure in the extension-side chamber L1 enlarged decreases. Therefore, a difference in pressure occurs between the compression-side chamber L2 and the extension-side chamber L1. The differential pressure is applied to the piston 20, and the damper body D exerts a damping force to suppress the contracting action of the rear cushion unit R.
The structure of the damper body D is not limited to the above-described one, and can be changed as appropriate. For example, although hydraulic oil is used as a fluid for generating a damping force in the present embodiment, other fluids may be used. Gas sealed in the gas chamber G3 can also be changed as appropriate. The gas chamber G3 may be pressurized to eliminate the base valve 11. The cylinder 1 and the tank 3 may be connected axially into one piece to eliminate the tank 3 of a type placed separately from the cylinder 1 as in the present embodiment. Although the liquid chamber L3 and the gas chamber G3 are partitioned by the free piston 30, a bladder, a bellows, or the like may be used for the partition. The cylinder 1 may be formed by inner and outer two cylinders to provide the liquid chamber L3 and the gas chamber G3 between them to form the damper body D in a double-cylinder type. The rod 2 may be extended through both the extension-side chamber L1 and the compression-side chamber L2 to be of a double-rod type,
Next, the tube member T forming the first air chamber G1 and the second air chamber G2 around the outer periphery of the damper body includes, as illustrated in
As illustrated in
As illustrated in
A groove 5c forming a gap between the chamber holder 5 and the first chamber member 40 is provided in an inside surface of the chamber holder 5. A space k1 between the rod 2 and the first chamber member 40 communicates with a space k2 between the first chamber member 40 and the second chamber member 41 via the gap. Both the spaces k1, k2 are filled with air. The combined space of both the spaces k1, k2 constitutes the first air chamber G1. A space formed around the slide pipe 16 covering the outer periphery of the cylinder 1, enclosed by the flange portion 10b of the rod guide 10, the first chamber member 40, and the cylindrical portion 6b (
As illustrated in
According to the above configuration, the first air chamber G1 functions as a main spring S1 for biasing in a direction to enlarge the capacity of the first air chamber G1, that is, in a direction to extend the rear cushion unit R by the elastic force of air sealed inside. The other second air chamber G2 functions as a balance spring S2 for biasing in a direction to enlarge the capacity of the second air chamber G2, that is, in a direction to contract the rear cushion unit R by the elastic force of air sealed inside.
When the rear cushion unit R extends, the tube member T moves upward in
In the present. embodiment, the rear cushion unit R has the main spring S1 and the balance spring S2 that bias it in opposite directions, thus being able to make the ride quality of the vehicle comfortable. To explain in more detail, although the vehicle body can be elastically supported only with the main spring S1, this results in the spring characteristics of the rear cushion unit as a whole constituted only by the characteristics of the main spring S1, having non-linear characteristics unique to air springs. Therefore, when the spring characteristics of the rear cushion unit are set to desired characteristics in the latter half of the stroke, the elastic force in the first half of the stroke, in particular, near the time of maximum extension can become excessive, degrading the ride quality. Thus, as in the present embodiment, the addition of the balance spring S2 can help contraction near the time of maximum extension of the rear cushion unit R, making the ride quality of the vehicle comfortable. In particular, it is preferable that the biasing force by the main spring S1 applied in the extension direction when the rear cushion unit R is at the time of maximum extension is offset by the balance spring S2 to approximate the combined characteristics of the main spring S1 and the balance spring S2 to the characteristics of a coil spring proportional to the stroke amount.
As shown in
Next, the first air passage 7 will be described in more detail. The bracket B1 in which a part of the first air passage 7 is formed has, as shown in
The air valve 70 is attached to a right end portion of the lateral hole B13 in
Thus, in the present embodiment, the air valve 70 for supplying and exhausting air to and from the first air chamber G1 is attached to the bracket B1 used for mounting the rear cushion unit R to the vehicle. This makes the air valve 70 less likely to be hidden by the frame F or a peripheral part of a motor held on the frame F or the like. Therefore, the air valve 70 is accessible with the rear cushion unit R mounted to the vehicle, and does not become inaccessible, thus preventing the adjustment of the pressure in the first air chamber G1 from becoming impossible.
In the present embodiment, an annular groove 5d along a circumferential direction is formed in a lower portion of the top portion 5a of the chamber holder 5 in
The configuration of the rear cushion unit R can be changed as appropriate. For example, a groove or the like may be formed in the bump cushion 9 or the chamber holder 5 to form a gap therebetween to enable quick supply and exhaust of air to and from the first air chamber G1. The bump cushion 9 may be changed to a coil spring, or the position of the bump cushion 9 may be changed. The bump cushion 9 may be eliminated if consideration is given to prevent causing significant degradation in ride quality by an impact at the time of maximum compression of the rear cushion unit R.
Although the first air chamber G1 and the second air chamber G2 are filled with air, individually, in the present embodiment, as used can be changed as appropriate if the first air chamber G1 or the second air chamber G2 can constitute a gas spring (pneumatic spring) using the elastic force of the gas. The gas may be the same as or different from gas in the gas chamber G3. In the present embodiment, the rear cushion unit R can be reduced in weight since the main spring S1 and the balance spring S2 are both air springs. Alternatively, the balance spring S2 may be changed to a coil spring. Further, in the present embodiment, the capacity of the first air chamber G1 can be increased since the first air chamber G1 includes the spaces k1, k2 . Alternatively, the first air chamber G1 may include only the space k1.
In the present embodiment, the slide pipe 16 is provided on the outer periphery of the cylinder 1 to form a structure to prevent the diameter-reduced portion 6c functioning as a sliding portion from directly slidably contacting the cylinder 1, and the sliding portion slidably contacts the outer periphery of the cylinder 1 via the slide pipe 16. Therefore, it is only necessary to smooth only the inner peripheral surface of the cylinder 1 for sliding, and the outer peripheral surface can remain rough, so that. the working of the cylinder 1 can be facilitated. However, the outer peripheral surface of the cylinder 1 may be smoothed to make the sliding portion directly slidably contact the outer periphery of the cylinder 1.
Hereinafter, the function and effect of the rear cushion unit R according to the present embodiment will be described.
In the present embodiment, the rear cushion unit (damper) R has the tubular bump cushion 9 provided on the outer periphery of the rod 2 for softening an impact at the time of maximum compression. The opening of the first air passage (passage) 7 on the first air chamber G1 side (the other side) faces the inner peripheral surface of the bump cushion 9. Therefore, air (gas) supplied and exhausted to and from the first air chamber (gas chamber) G1 through the first air passage (passage) 7 passes through the gap formed around the bump cushion 9, which can prevent discharge of a large amount of air (gas) from the first air chamber (gas chamber) G1 in a short period of time. The position at which the bump cushion 9 is provided can be changed as appropriate. The bump cushion 9 may be eliminated.
In the present embodiment, the rear cushion unit (damper) R includes the cylinder 1, the rod 2 movably inserted in the cylinder 1, the tube member T connected to the rod 2 and forming the first air chamber (gas chamber) G1 chat is enlarged and reduced in capacity by the relative movement, of the cylinder 1 and the rod 2, the bracket B1 provided at the end portion of the rod 2 protruding from the cylinder 1, the first air passage (passage) 7 formed in the bracket B1 and the rod 2 and communicating with the first air chamber (gas chamber) G1, and the air valve (can supply and exhaust valve) 70 attached to the bracket B1 and provided at the end portion of the first air passage (passage) 7 on the atmosphere side (one side).
The bracket B1 is a component used for mounting the rear cushion unit (damper) R to the vehicle. Thus, the air valve (gas supply and exhaust valve) 70, when attached to the bracket B1, is less likely to be hidden by the frame F or a peripheral part of a motor held on the frame F or the like. Therefore, the air valve 70 is accessible with the rear cushion unit R mounted to the vehicle, and does not become inaccessible, thus being able to prevent the adjustment of the pressure in the first air chamber (gas chamber) G1 from becoming impossible.
The tube member T may be directly connected to the rod 2 or may be indirectly connected via another member. The state where the tube member T is connected to the rod 2 includes both a case where it is directly connected and a case where it is indirectly connected, and may be either of them. This change is possible irrespective of the position at which the bump cushion 9 is provided and the presence or absence of the bump cushion 9.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-118163 | Jun 2015 | JP | national |
