JP2595714Y2 - Fluid pressure type shock absorber - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber that absorbs kinetic energy of a load by means of a fluid such as hydraulic pressure, and controls a shock absorber that absorbs shocks and vibrations when the load is stopped, or controls the speed of the load. It is used as a hydro-checker and so on.

[0002]

2. Description of the Related Art Generally, in a hydraulic shock absorber, when a piston moves in a pressure tube having a plurality of holes arranged along an axial direction, pressure oil in the pressure tube flows out of the holes, The buffering action is exerted by the back pressure in the pressure tube based on the resistance (outflow resistance) when the pressure oil flows out from the hole.

Further, in order to adjust the magnitude of the buffering action according to the magnitude of the kinetic energy of the load, the outflow resistance of the pressure oil from the hole can be variably adjusted. FIG. 4 is a sectional view showing an adjusting mechanism of the conventional hydraulic shock absorber 80. As shown in FIG.

[0004] In the conventional hydraulic shock absorber 80, a pressure tube 81 is provided to adjust the outflow resistance of the pressure oil HY.
Orifices 85 each having an inner diameter substantially equal to the outer diameter of the pressure tube 81 and corresponding to the hole 82 of the pressure tube 81.
The metering tube 84 having the pressure tube 8
1. The eccentric groove 83 is formed coaxially with the pressure tube 81 and formed on the outer peripheral surface of the pressure tube 81 so as to communicate with the respective holes 82 and has a bottom portion eccentric to the outer peripheral circle over a central angle of about 180 degrees. .

In this case, the outflow resistance increases and decreases in accordance with the viscous length L along the arc from the cut point a of the eccentric groove 83 to the point b of the orifice 85. The viscosity length L is adjusted by changing the rotation angle position with respect to
The outflow resistance of Y is adjusted.

[0006]

However, in the above-described conventional hydraulic shock absorber 80, the outer peripheral surface of the pressure tube 81, the inner peripheral surface of the metering tube 84, and the eccentric groove 8 are not provided.
Since high processing accuracy is required for 3 and the like, the manufacturing cost increases.

The pressure oil HY is adjusted by variably adjusting the viscous length L.
Therefore, the pressure oil HY is easily affected by a change in the viscosity coefficient due to a temperature change of the pressure oil HY, and the magnitude of the buffering action due to the temperature change, that is, the performance of the buffer device 80 is largely fluctuated.

In particular, when the mass or propulsive force of the load is large and the speed is small, it is necessary to particularly increase the outflow resistance of the pressure oil HY in order to obtain a sufficient buffering action. In the case of No. 80, the outflow of the pressure oil could not be sufficiently squeezed by adjustment. For this reason, it is necessary to increase the pressure receiving area of the piston, and there is a problem that the size of the device is increased.

In view of the above problems, the present invention eliminates the need for a metering tube that requires high precision, reduces costs, and reduces fluctuations in the buffering action due to temperature changes, resulting in an increase in the size of the device due to insufficient squeezing. It is an object of the present invention to provide a fluid-type shock absorber without any problem.

[0010]

According to a first aspect of the present invention, there is provided an apparatus for solving the above-mentioned problems, in which a fluid in a pressure tube flows out of a throttle hole by moving a piston in the pressure tube. In addition, in the fluid pressure type shock absorber in which the buffering action is exerted by the back pressure in the pressure tube based on the outflow resistance from the throttle hole, the inside of the pressure tube is closed at a position corresponding to the bottom surface of the pressure tube. inner cover for the, the
A pressure tube is provided so as to be movable in the axial direction , at least one of the throttle holes is provided in the inner cover, and an area of an opening of the throttle hole provided in the inner cover is adjusted. An adjustment member is provided so as to be operable from outside , and the adjustment member is
Eccentric cam that can rotate around the axis along the
It is constituted by.

[0011] The device according to the invention of claim 2 is the above-mentioned piston
Passes through all the throttle holes provided in the pressure tube
In the rear effective stroke, which is the stroke after
Flows from only the throttle hole provided in the inner cover.
The body is configured to flow out .

According to a third aspect of the present invention, the piston is provided with a packing for sealing between the piston and the pressure tube.

[0013]

The area of the opening of the aperture is adjusted by the adjusting member. Thereby, the resistance of the fluid flowing out of the throttle hole is variably adjusted, and the kinetic energy is absorbed according to the speed of the load.

Since the inner cover is provided so as to be movable in the axial direction with respect to the pressure tube, the inner cover comes into contact with the eccentric cam due to the pressure accompanying the movement of the piston and the opening area of the throttle hole is reduced by the rotation angle of the eccentric cam. Adjusted according to position.

[0015]

1 is a sectional front view of a shock absorber 1 according to the present invention, FIG. 2 is a view for explaining the operation of an adjusting device 20 of the shock absorber 1 of FIG. 1, and FIG. FIG. 4 is a diagram showing a relationship with an orifice area.

The shock absorber 1 includes a reservoir tube 11, a pressure tube (inner tube) 12, a bush 13, an inner cover 14, a piston 15, and a piston rod 1.
6, a compression coil spring 18, an accumulator 19, an adjusting device 20, and the like.

The reservoir tube 11 has a bottomed cylindrical shape having a bottom portion 11a, the inside of which is sealed by a bush 13, and constitutes an entire container for storing the pressure oil HY.
The piston 15 slides on the inner peripheral surface of the pressure tube 12 mounted concentrically with the reservoir tube 11. The piston 15 is provided with a packing 17 for preventing leakage between the piston 15 and the pressure tube 12, and is closed when the piston 15 moves in the left direction (the direction of the arrow M1) in FIG. 1 and moves in the opposite direction. A check valve that is sometimes open is provided.

The inner cover 14 is provided with the pressure tube 12
At the left end face (bottom) of the pressure tube 1
The pressure tube 12 is provided so that there is no leak between the pressure tube 2 and the pressure tube 12.

A piston rod 16 is connected to the piston 15, and the piston rod 16 projects through the bush 13 to the outside. The compression coil spring 18 urges the piston 15 to the right and normally returns the piston 15, and also urges the inner cover 14 to the left to bring the inner cover 14 into contact with an eccentric cam 21 described later. I have. The accumulator 19 absorbs the volume fluctuation in the chamber 31 due to the stroke position of the piston 15.

The pressure tube 12 is provided with a plurality of holes 41, 41,... Each forming a thin blade orifice arranged in the axial direction. In addition, inner cover 1
4 is provided with a hole 42 also forming a thin blade orifice.

The adjusting device 20 includes an eccentric cam 21 rotatably provided on the bottom 11a of the reservoir tube 11, an adjusting knob 22 for rotating the eccentric cam 21 from the outside,
It consists of a lock screw 23 for fixing the adjustment knob 22.

The eccentric cam 21 has a cam plate 21 at its tip.
The end surface of “a” is arranged to face the hole 42, and the opening area of the hole 42 is adjusted according to the rotation angle position of the cam plate 21 a.

That is, as shown in FIG. 2, by rotating the adjustment knob 22, the cam plate 21 is rotated.
a can be adjusted to any state between the state in which the hole 42 rotates and the state in which the hole 42 is completely closed to the state in which the hole 42 is completely opened. By this adjustment, the orifice area (or throttle amount) in the stroke after the piston 15 has passed through all the holes 41, that is, the effective rearward stroke, is adjusted.

That is, as shown in FIG. 3, when the piston 15 starts moving from the position shown in FIG. 1 in the direction of arrow M1, the initial orifice area is changed to the opening of all the holes 41 and 42. Although it is based on the total area, the hole 41 is sequentially closed by the movement of the piston 15,
The orifice area gradually decreases. Until all holes 41 are passed, this is the forward effective stroke. That is, in the front effective stroke, the orifice area varies according to the stroke position of the piston 15.

In the rear effective stroke, the orifice area is only the opening area of the hole 42 and can be adjusted from zero to the maximum area of the hole 42. It does not change depending on the stroke position of the piston 15.

Reference numeral 51 denotes a packing, and 52 and 53 detent pins. Therefore, when the load collides with the piston rod 16 and the piston 15 moves in the direction of the arrow M1, the pressure oil HY in the chamber 31 flows out of the holes 41 and 42 into the outer chamber 32. At this time, the piston 15 receives resistance due to the back pressure generated in the chamber 31, and the kinetic energy of the load is absorbed.

By adjusting the eccentric cam 21, the orifice area in the rear effective stroke can be varied from zero to the maximum area of the hole 42, so that the outflow amount can be sufficiently reduced and the outflow resistance can be increased. Therefore, even when the mass or propulsion of the load is large and the speed is small,
The kinetic energy of the load can be absorbed and stopped without impact, and it is not necessary to increase the pressure receiving area of the piston as in the related art, and the device can be downsized.

Further, the packing 17 is provided on the piston 15, so that the pressure oil HY in the chamber 31 does not leak from the gap between the piston 15 and the pressure tube 12 as in the conventional case, and particularly the minute oil in the rearward effective stroke. A large amount of aperture can be realized. Therefore, the size of the apparatus can be further reduced.

In the above-described embodiment, since the opening area of the hole 42 is changed by the eccentric cam 21, the influence of the fluctuation of the viscosity coefficient of the pressure oil HY is small, and the fluctuation of the buffer action due to the temperature change is small.

Further, the structure of the shock absorber 1 is simple,
Since a conventional metering tube that requires high-precision squeezing with the pressure tube 12 is not required, the cost can be reduced.

In the above-described embodiment, the kinetic energy when the speed of the load is high can be absorbed without excessive drag in the effective forward stroke by the plurality of holes 41.

In the above embodiment, the inner cover 14 is movable with respect to the pressure tube 12 and the eccentric cam 21 is moved by the compression coil spring 18 and the back pressure in the chamber 31.
The inner cover 14 and the eccentric cam 21 are in close contact with each other with a simple structure, and the hole 42 can be almost completely closed by the eccentric cam 21.

The shock absorber of the present invention can be applied to a shock absorber for absorbing shock or vibration, or to a hydro-checker for speed control during drilling.

That is, for example, in the case of a hydro checker for controlling the feed speed of the drill, the effective forward stroke can be used as the rapid feed section of the drill, and the effective backward stroke can be used as the cutting feed section of the drill. Further, the entire stroke can be used as the cutting feed section without providing the hole 41. That is, when the collision speed is zero, it is possible not to provide the front effective stroke.

As described above, by designing the orifice of the hole 41 so as to absorb the sum of the kinetic energy of the load and the propulsion energy within the effective forward stroke, it is possible to prevent the initial drag from becoming excessive. At the same time, the well-designed bore 42 and adjusting device 20 can provide the required control speed in the rear effective stroke.

In the above embodiment, the number of holes 41 and 42 can be changed variously. Although the holes 41 and 42 are thin blade orifices, other shapes such as groove orifices may be used. The eccentric cam 21 may be rotated by a motor or the like instead of or together with the adjustment knob 22. In addition, the structure, shape, size, material, etc. of each part of the shock absorber 1 can be variously changed in accordance with the gist of the present invention.

[0037]

According to the present invention, it is possible to reduce the cost by eliminating the need for a metering tube that requires high precision and accuracy, to reduce fluctuations in the buffering action due to temperature change, and to reduce the device performance due to insufficient throttling. There is no increase in size. Therefore, the performance of the shock absorber is not affected by the temperature, and a stable shock absorbing action can be exhibited.

In addition, the inner cover and the eccentric cam are in close contact with each other with a simple structure, and the aperture hole can be almost completely closed by the eccentric cam. According to the invention of claim 2, backward effective
In the stroke, squeeze outflow sufficiently to reduce outflow resistance.
Can be bigger. According to the third aspect of the present invention, the size of the apparatus can be further reduced.

[Brief description of the drawings]

FIG. 1 is a sectional front view of a shock absorber according to the present invention.

FIG. 2 is a view for explaining the operation of the adjusting device of the shock absorber of FIG. 1;

FIG. 3 is a diagram showing a relationship between a stroke of a shock absorber and an orifice area.

FIG. 4 is a sectional view showing an adjusting mechanism of a conventional hydraulic shock absorber.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shock absorber (fluid pressure shock absorber) 12 Pressure tube 14 Inner cover 15 Piston 17 Packing 21 Eccentric cam (adjustment member) 22 Adjustment knob 41 Hole (throttle hole) 42 Hole (throttle hole) HY Hydraulic oil (fluid)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16F 9/00-9/58

Claims (3)

(57) [Scope of request for utility model registration] The piston moves within the pressure tube, so that the fluid in the pressure tube flows out of the throttle hole, and a buffering action is provided by the back pressure in the pressure tube based on the resistance of the flow from the throttle hole. in hydraulic cushioning apparatus that exert, at a position corresponding to the bottom surface of the pressure tube, the inner cover for closing the said pressure tube, said pressure
The inner cover is provided so as to be movable in the axial direction , and the inner cover has at least one of the throttle holes.
An adjusting member for adjusting the area of the opening of the throttle hole provided in the inner cover is provided so as to be operable from outside , and the adjusting member has an axis along a moving direction of the piston.
A hydraulic shock absorber characterized by being an eccentric cam rotatable about the center . 2. A hydraulic shock absorber according to claim 1, wherein said piston has a throttle hole formed in said pressure tube.
Backward effective straw that is a stroke after passing through all
The aperture hole provided in the inner cover
A fluid pressure type shock absorber characterized in that a fluid flows out only from the fluid pressure shock absorber. 3. The fluid-type shock absorber according to claim 1, wherein the piston is provided with a packing for sealing between the piston and the pressure tube. Pressure type shock absorber.