JP2581305Y2 - Hydraulic cylinder cushion mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cushion mechanism for a hydraulic cylinder, and more particularly, to a cushion mechanism for a hydraulic cylinder used in construction equipment for reducing the impact near the stroke end of a piston working chamber of a hydraulic cylinder. About.

[0002]

2. Description of the Related Art A conventional cushion mechanism of a hydraulic cylinder of this type is shown in an overall view in FIG. 2, and an essential part thereof is shown in an enlarged sectional view in FIG. As can be seen from FIGS. 2 and 3, the cylinder cover 4 is welded to the open end of the cylinder tube 3 for the hydraulic cylinder to solidify it, and the cylinder cover 4 advances and retreats to the working chamber 11 inside the cylinder tube 3 for the hydraulic cylinder. The free piston 2 is inserted, the piston 2 is supported by the piston rod 1, the nut 18 is tightened and fixed, and when the piston 2 is moved rightward, the rightward operation of the cylinder tube 3 for the hydraulic cylinder is performed. The hydraulic oil in the chamber 11 is pushed by the piston 2, passes through the cushion sleeve 5 b and the hydraulic oil introduction passage 19, and is discharged from the discharge port 13. When the piston 2 further moves rightward and reaches near the stroke end of the piston working chamber of the hydraulic cylinder, the cushion piston 6 fits into the cushion sleeve 5b, and the cylinder tube 3
Hydraulic oil in the right working chamber 11 passes through a very narrow annular gap between the outer peripheral surface of the cushion piston 6 and the inner peripheral surface of the cushion sleeve 5b. The hydraulic pressure of the piston 11 rises, and the high-pressure hydraulic oil weakens the forward speed of the piston 2 and finally stops the piston 2. This alleviates the shock at the stroke end of the piston 2 in the piston working chamber of the hydraulic cylinder.

[0003]

However, the conventional hydraulic cylinder cushion mechanism as described above has a problem in the structure of the hydraulic cylinder cushion mechanism, and it is necessary to solve the problem. That is, in order to improve the effectiveness of the cushion of the cushion mechanism of the conventional hydraulic cylinder, it is necessary to reduce the annular gap between the outer peripheral surface of the cushion piston 6 and the inner peripheral surface of the cushion sleeve 5b. Narrow cushion piston 6
Also, due to manufacturing errors such as eccentricity, roundness and inclination of the cushion sleeve 5b, abrasion of the piston seal or elastic deformation of the piston rod, etc., when the cushion piston is fitted into the cushion sleeve, the cushion piston does not fit well, causing galling or the like. There was an inconvenience. Furthermore, once these mechanisms are incorporated into the hydraulic cylinder, there is a disadvantage that inspection and replacement cannot be performed unless the hydraulic cylinder itself is disassembled. In view of the above, the present invention is intended to solve the above-mentioned disadvantage by providing an annular gap type cushion mechanism comprising a cushion piston and a sleeve in which a cushion oil of a different system from the hydraulic oil system of the hydraulic cylinder is sealed at the end of the hydraulic cylinder. Is what you do.

[0004]

According to the present invention, there is provided a cushion container 5 provided at an end of a hydraulic cylinder on a piston side, which seals oil, and is inserted into the cushion container 5 and is provided on a hydraulic cylinder side wall surface of the cushion container 5. A cushion piston 6 having a piston nose portion projecting through the provided through hole toward the hydraulic cylinder, a spring 10 provided between the cushion piston and the wall surface of the cushion container 5 for biasing the cushion piston 6 toward the hydraulic cylinder side wall surface; A cushion oil chamber 8 provided behind the cushion piston 6 of the cushion container 5, a discharge oil chamber 9 having a larger diameter than the cushion oil chamber 8 provided on the outer periphery of the piston 6 on the hydraulic cylinder side of the cushion container 5, The cushion oil chamber 8 is formed between the inner wall surface and the outer peripheral surface of the cushion piston 6.
And an annular gap 7 communicating the oil discharge chamber 9 with the annular gap 7. The annular gap 7 has a throttling function for generating flow resistance when pressure oil in the cushion chamber flows therethrough. It is.

[0005]

Next, the operation resulting from the above configuration will be described. A cushion chamber in which oil other than hydraulic oil in the piston operating chamber of the hydraulic cylinder is accommodated at the end of the hydraulic cylinder as shock absorbing oil. Is provided so that the tip of the cushion piston in the cushion chamber projects into the piston working chamber of the hydraulic cylinder to seal around the cushion piston. The shock absorbing oil that works the cushion piston is separated from each other and does not mix with each other. Due to such a configuration, when the tip of the piston in the piston working chamber of the hydraulic cylinder hits the tip of the cushion piston in the cushion chamber, the shock absorbing oil in the cushion chamber works to absorb the shock. When the piston 2 that moves freely in the hydraulic cylinder moves rightward, the hydraulic oil in the working chamber 11 on the right side of the cylinder tube 3 for the hydraulic cylinder is pushed by the piston 2 and discharged from the boat 13. . further,
When the piston 2 moves rightward and reaches near the stroke end of the piston working chamber of the hydraulic cylinder, the piston nose of the piston of the hydraulic cylinder comes into contact with and pushes the cushion piston nose of the cushion piston in the cushion chamber. As a result, the rear enormous head of the cushion piston is moved rightward, high pressure is applied to the cushion piston 6 in the cushion oil chamber 8 provided in the cushion container, and the shock absorbing oil in the cushion oil chamber 8 is applied. Is discharged through a very narrow annular gap between the outer peripheral surface of the cushion piston 6 and the inner peripheral surface of the cushion oil chamber 8 to the discharge oil chamber 9. The oil pressure in the oil chamber 8 increases,
As a result, the forward speed of the cushion piston is reduced and finally stopped. This alleviates the impact when the piston 2 approaches the stroke end of the piston working chamber of the hydraulic cylinder.

[0006]

FIG. 1 is a sectional view showing an embodiment of the present invention. In FIG. 1, a piston rod 1 of a hydraulic cylinder 2 is shown.
The piston rod 1 is inserted into a cylinder tube 3 for a hydraulic cylinder, a cylinder cover 4 is fixed to the cylinder tube 3, and a cushion container 5 is attached to a flange portion at an end of the cylinder cover 4. Butted with bolts 12 and axially slide the enlarged head 6a of the rear half of the cushion piston 6 into the sleeve portion 5a forming the cushion oil chamber 8 of the cushion container 5. The cushion oil is freely inserted and the shock absorbing oil is sealed in the cushion container 5, but is divided into a cushion oil chamber 8 and a discharge oil chamber 9 having a diameter larger than that of the cushion oil chamber 8 by the inserted portion. Both chambers have the inner peripheral surface of the sleeve portion 5a and the enlarged head 6
a through an annular gap 7 between the two. On the other hand, the first half 6 b of the cushion piston 6 is
b, is inserted through the axial through hole so as to be able to seal, and the front end portion 6c of the front half portion 6b is protruded into the working chamber 11 for the hydraulic cylinder so as to be able to advance and retreat. The oil in the discharge oil chamber 9 of the cushion container 5 and the oil in the working chamber 11 of the hydraulic cylinder are securely sealed by the seal member 15 and do not mix with each other. A flange portion at the end of the cylinder cover 4;
A portion where the flange portion of the cushion container 5 is abutted is fastened with a bolt 12, and
The sealing oil 14 is interposed to prevent the working oil in the working chamber 11 from leaking to the outside. The port 13 is a port for introducing hydraulic oil into the working chamber 11. Here, when the piston 2 of the hydraulic cylinder moves rightward and reaches the vicinity of the stroke end, the nose 1a at the tip of the piston rod 1 becomes the nose tip 6 of the entire half of the cushion piston 6.
c, and pushes the cushion piston 6 forward to push the shock absorbing oil in the cushion oil chamber 8. Therefore, the oil in the cushion oil chamber 8 is discharged through the annular gap 7 to the discharge oil chamber 9 on the opposite side. At this time, the pressure in the cushion oil chamber 8 increases due to the flow resistance of the oil passing through the annular gap 7, and a force for pushing back the cushion piston 6 acts. As a result, the speed of the piston 2 of the hydraulic cylinder is reduced, and the impact near the stroke end is reduced. Also, the faster the speed of the piston 2 of the hydraulic cylinder, the greater the amount of shock absorbing oil passing through the annular gap 7, and accordingly, the pressure in the cushion oil chamber 8 increases and the deceleration effect increases. When the piston 2 moves to the left from the stroke end, the cushion piston 6 is moved in the process of separating the nose 1a at the tip of the piston rod 1 from the nose tip 6c of the front half of the cushion piston 6. It is pushed back to the left by the residual pressure in the oil chamber 8 and the return spring 10, and finally, the cushion piston 6 is
b is pressed against the surface. However, the amount of oil flowing in and out between the discharge oil chamber 9 and the cushion oil chamber 8 must be the same . Therefore, the cushion piston 6 is closed.
Cushion piston 6 on the cushion oil chamber side and the discharge oil chamber side
It is necessary to make the amount of increase or decrease in volume due to movement equal . The cushion oil chamber 8 of the container for the cushion 5 and the working chamber 11 of the piston 2 of the hydraulic cylinder can be filled with different oils instead of the same oil. Also, while bleeding air through the plurality of ports 16, oil is injected, and after the injection is completed,
Plug with plug 17.

[0007]

[Effect] The present invention has the following effects because it has the above-described configuration. 1. Since the nose part sleeve at the tip of the piston rod, whose accuracy is extremely uncertain, is not encroached on, the problem of galling and the like is eliminated, and the annular gap can be reduced, so that a high-performance cushion mechanism can be designed. . 2. Since the oil of a different system from the hydraulic oil in the piston working chamber of the hydraulic cylinder is used as the oil for shock absorption, the effect of the cushion can be increased and the cushion can be stabilized. In addition, even if the temperature of the hydraulic oil in the piston working chamber of the hydraulic cylinder rises, and the viscosity of the hydraulic oil decreases due to the temperature rise, the effect of the cushion does not decrease. 3. At the end of the hydraulic cylinder, an annular clearance type cushion mechanism consisting of a cushion piston and a sleeve filled with cushioning oil separate from the hydraulic oil system of the hydraulic cylinder is provided. However, the cushion container can be easily removed from the hydraulic cylinder to be replaced and inspected, and there is an effect that it is not necessary to disassemble the cylinder itself as in the related art. 4. The cushion oil chamber 8 and the discharge oil chamber 9
And the inner peripheral surface 5a of the cushion container for guiding it
The pressure oil is communicated through the formed thin cylindrical annular gap 7
Large aperture effect, in other words, big shoes
The effect can be obtained .

[Brief description of the drawings]

FIG. 1 is a sectional view of a cushion mechanism of a hydraulic cylinder according to an embodiment of the present invention.

FIG. 2 is a front view of the overall configuration of the hydraulic cylinder, showing a cross-sectional view of a main part of a conventional cushion mechanism of the hydraulic cylinder.

FIG. 3 is an enlarged sectional view of a main part of a cushion mechanism of the hydraulic cylinder shown in FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Piston rod 2 Piston 3 Cylinder tube 4 Cylinder cover 5 Cushion container 5a Sleeve 5b Partition wall 6 Cushion piston 6a Enlarged rear part 6b Front nose part 6c Tip part 7 Annular clearance 8 Cushion oil chamber 9 Drain oil chamber 10 Return spring 11 Working chamber 12 bolt 13 port 14 seal member 15 seal member 16 port 17 plug 18 nut 19 hydraulic oil introduction path

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F15B 15/14 360-15/22 F16F 9/00

Claims (1)

(57) [Scope of request for utility model registration] An oil-sealed cushion container provided at a piston-side end of a hydraulic cylinder, and a hydraulic cylinder closer to a hydraulic cylinder than a through hole inserted into the cushion container and provided in a side wall surface of the hydraulic cylinder of the cushion container. Cushion piston 6 having a piston nose portion penetrating through it, a spring 10 provided between the cushion piston and the wall surface of cushion container 5 for urging cushion piston 6 against the hydraulic cylinder side wall surface, and cushion piston 6 of cushion container 5 A cushion oil chamber 8 provided at the rear, a discharge oil chamber 9 larger in diameter than the cushion oil chamber 8 provided on the outer periphery of the piston 6 on the hydraulic cylinder side of the cushion container 5, an inner wall surface of the cushion container 5, and an outer peripheral surface of the cushion piston 6 And an annular gap 7 communicating between the cushion oil chamber 8 and the discharge oil chamber 9. Said annular when gap 7 flowing therethrough pressurized oil cushion chamber, cushion mechanism of a hydraulic cylinder, characterized in that it comprises a stop function which allowed to produce a flow resistance.