CN111577702B - Buffering method of hydraulic actuating cylinder at stroke starting end - Google Patents

Buffering method of hydraulic actuating cylinder at stroke starting end Download PDF

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Publication number
CN111577702B
CN111577702B CN202010447403.6A CN202010447403A CN111577702B CN 111577702 B CN111577702 B CN 111577702B CN 202010447403 A CN202010447403 A CN 202010447403A CN 111577702 B CN111577702 B CN 111577702B
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piston
rod
buffer
cylinder
cavity
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CN111577702A (en
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张振华
张鑫
曹秀荣
李春萍
王飞
李大让
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Beijing Institute of Specialized Machinery
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Beijing Institute of Specialized Machinery
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1423—Component parts; Constructional details
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1423—Component parts; Constructional details
    • F15B15/1447—Pistons; Piston to piston rod assemblies
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)

Abstract

The invention relates to a buffering method of a hydraulic actuating cylinder at the stroke starting end, and relates to the technical field of fluid transmission. The buffer function of the hydraulic actuating cylinder at the initial end of the working stroke is realized through the built novel internal buffer structure, and the problem that the traditional internal buffer structure is difficult to realize the buffer of the initial end of the actuating cylinder can be solved; compared with the external buffer mode of the actuating cylinder, the hydraulic actuating cylinder designed in the implementation process of the method has the advantages of simple structure, convenience in installation and maintenance, low use cost and the like.

Description

Buffering method of hydraulic actuating cylinder at stroke starting end
Technical Field
The invention relates to the technical field of fluid transmission, in particular to a buffering method of a hydraulic actuating cylinder at the starting end of a stroke.
Background
The hydraulic cylinder is an important reciprocating-type executing element in a hydraulic system, and the actuating performance of the hydraulic cylinder has important influence on the system. When the hydraulic ram moves at a fast speed or has a high load inertia, it is easy to generate an impact at the initial or final end of the ram stroke. Wherein, the impact at the initial end of the working stroke acts on the load mainly through the piston rod of the actuating cylinder, so that the load is subjected to a larger impact load instantaneously, thereby generating vibration and noise and even instability of movement. The impact at the end of the working stroke is mainly generated because the piston of the actuating cylinder impacts the cylinder bottom rigidly and then is transmitted to an external load through the cylinder wall, so that large impact vibration and noise are generated, the working stability of a moving part is further influenced, a fastener is loosened seriously, the hydraulic actuating cylinder and related equipment are damaged, and the service life of the hydraulic actuating cylinder and the related equipment is shortened.
At present, a hydraulic actuating cylinder mostly adopts structural types such as a stepped cylinder, a conical step, a short flute hole and the like to realize buffering through oil dynamic variable throttling, and belongs to an internal buffering mode. However, the above-mentioned buffer structure is mostly installed at the end of the stroke of the actuator cylinder, in order to solve the problem of buffering and impact vibration at the end of the stroke of the actuator cylinder, but it is difficult to solve the problem of buffering at the initial end of the working stroke of the hydraulic actuator cylinder. Therefore, for the buffering problem at the initial end of the working stroke of the hydraulic actuator cylinder, buffering is mostly realized by an external buffering mode, namely, a throttle valve, an overflow valve or an energy accumulator and other components are additionally arranged in a hydraulic system. Although the external buffering mode is flexible and adjustable, the external buffering mode occupies a larger installation space, so that the structure of the hydraulic system is more complicated, and the use and maintenance cost of the hydraulic system is increased. Therefore, a novel internal buffering form is constructed to realize the buffering function of the actuating cylinder at the initial end of the working stroke, and the novel internal buffering form has important significance for making up the buffering defect of the existing hydraulic actuating cylinder, simplifying the structure of a hydraulic system, reducing the installation cost of the system and the like.
Disclosure of Invention
Technical problem to be solved
The technical problem to be solved by the invention is as follows: designing a buffer method of a hydraulic actuator cylinder at the initial end of a stroke, realizing the buffer function of the hydraulic actuator cylinder at the initial end of the working stroke by constructing a novel internal buffer structure, and solving the problem that the traditional internal buffer structure is difficult to realize the buffer of the initial end of the actuator cylinder; on the other hand, compared with the external buffer mode of the actuating cylinder, the hydraulic actuating cylinder designed in the implementation process has the advantages of simple structure, low use and maintenance cost and the like.
(II) technical scheme
In order to solve the above technical problem, the present invention provides a method for buffering a hydraulic actuator at a stroke start, the method being implemented based on a design of the hydraulic actuator, the hydraulic actuator being designed to include: the device comprises a cylinder body 1, a cylinder bottom 2, a piston 4, a buffer piston 7, a guide sleeve 9, a static seal 10, a locking sleeve 11, a dust ring 13, a piston rod 14, a locking nut 15 and a rod head 16;
the cylinder body 1 is provided with a first oil port a and a second oil port b at two ends respectively, a cylinder bottom 2 is arranged at one side of the cylinder body 1 close to the first oil port a, and a guide sleeve 9 and a locking sleeve 11 are sequentially arranged at one side of the cylinder body 1 close to the second oil port b from inside to outside; the piston 4 is positioned in the cylinder 1, the outer edge of the piston 4 is of a cylindrical structure, the interior of the piston 4 is of a blind hole-shaped structure, the bottom surface of the piston 4, the inner wall surface of the cylinder 1 and the end surface of the cylinder bottom 2 form a rodless cavity c, and the top surface of the piston 4, namely the opening end surface of the blind hole, the inner wall surface of the cylinder 1 and the end surface of the guide sleeve 9 form a rod cavity d; the outer edge of the buffering piston 7 is of a cylindrical structure, the interior of the buffering piston 7 is of a stepped hole structure, and one end, with a larger diameter, of the stepped hole of the buffering piston 7 extends into the interior of the piston 4 and is fixedly connected with the inner wall surface of the piston 4; the piston rod 14 is of a stepped shaft structure, wherein the part with the larger diameter is positioned in the buffer piston 7 and is provided with a plurality of damping through holes g along the axial direction, the bottom surface of the end with the larger diameter of the piston rod 14, the inner wall surface of the buffer piston 7 and the bottom surface of a blind hole of the piston 4 form a rodless buffer cavity e, the shaft shoulder of the stepped shaft of the piston rod 14 and the inner wall surface of the buffer piston 7 form a rod buffer cavity f, and the end with the smaller diameter of the piston rod 14 sequentially penetrates through the inner hole of the buffer piston 7, the inner hole of the guide sleeve 9 and the inner hole of the locking sleeve 11 to extend out of the end surface of the cylinder body 1 and is connected and fastened with the rod head 16 through a locking nut 15;
in the hydraulic actuating cylinder with the stroke starting end buffering function, the outer edge of the part with the smaller diameter of the piston rod 14 is in clearance fit with the inner hole of the buffering piston 7, so that an annular damping gap h is formed;
in the hydraulic actuator cylinder buffered at the stroke starting end, a first oil port a is communicated with a rodless cavity c, a second oil port b is communicated with a rod cavity d, the rod cavity d is communicated with a rod buffer cavity f through an annular damping gap h, and the rod buffer cavity f is communicated with a rodless buffer cavity e through a damping through hole g;
the method for buffering the hydraulic actuator cylinder at the stroke starting end based on the hydraulic actuator cylinder comprises the following steps:
when the actuating cylinder is in a retraction state, the piston rod 14 is in a retraction state relative to the cylinder body 1, the piston rod 14 is in an extension state relative to the buffer piston 7, namely the bottom surface of the piston 4 is close to the inner end surface of the cylinder bottom 2 or the two are in direct contact, and the shaft shoulder end surface of the piston rod 14 is close to the step end surface of the stepped hole of the buffer piston 7 or the two are in direct contact;
when the movable cylinder starts to extend, oil enters the rodless cavity c from the first oil port a, the piston 4, the buffer piston 7 and the piston rod 14 are further pushed to extend outwards together, an external load reversely pushes the piston rod 14 through the rod head 16, under the combined action of the external load and the oil, the oil in the rodless buffer cavity e is extruded and enters the rod buffer cavity f through the damping through hole g, the rod buffer cavity f is extruded into the rod cavity d through the annular damping gap h and flows out through the second oil port b together with the oil in the rod cavity d, and in the process that the oil firstly flows into the rod buffer cavity f from the rodless buffer cavity e through the damping through hole g and the annular damping gap h and then flows into the rod cavity d, the piston rod 14 retracts relative to the buffer piston 7 to play a buffering role;
when the actuating cylinder extends for a certain distance, all the oil in the rodless buffer cavity e is extruded out, the bottom surface of the piston rod 14 is contacted with the end surface of the inner hole of the piston 4, and the buffering process is stopped; the actuating cylinder continues to extend until the actuating cylinder extends to the right position when the buffer piston 7 is contacted with the guide sleeve 9;
when the actuating cylinder is in an extending state, the piston rod 14 is in an extending state relative to the cylinder body 1, the piston rod 14 is in a retracting state relative to the buffer piston 7, namely the buffer piston 7 is close to the guide sleeve 9 or the two are in direct contact, and the bottom surface of the piston rod 14 is close to the end surface of the inner hole of the piston 4 or the two are in direct contact;
when the movable cylinder starts to retract, oil enters the rod cavity d from the second oil port b, the piston 4, the buffer piston 7 and the piston rod 14 are further pushed to perform retraction movement together, an external load pulls the piston rod 14 through the rod head 16, the oil in the rod buffer cavity f is extruded under the combined action of the external load and the oil, one part of the oil enters the rodless buffer cavity e through the damping through hole g, the other part of the oil enters the rod cavity d through the annular damping gap h and pushes the movable cylinder to retract together with the oil in the rod cavity d, the oil flows into the rodless buffer cavity e from the rod buffer cavity f through the damping through hole g and flows into the rod cavity d from the rod buffer cavity f through the annular damping gap h, and the piston rod 14 performs outward extension movement relative to the buffer piston 7 to perform a buffering function;
after the actuating cylinder retracts for a certain distance, all oil in the rod buffer cavity f is extruded into the rodless buffer cavity e and the rod cavity d, the shaft shoulder end surface of the piston rod 14 is close to the step end surface of the stepped hole of the buffer piston 7 or the two end surfaces are in direct contact, and the buffering is stopped from this point; the ram continues to retract until the underside of the piston 4 contacts the inner end surface of the base 2 and the ram is retracted into position.
Preferably, the outer edge of one end of the guide sleeve 9 extends into the cylinder 1 and is sealed with the inner wall surface of the cylinder 1 through a static seal 10, the end surface of the other end of the guide sleeve 9 is pressed by a locking sleeve 11, and the locking sleeve 11 is connected and fastened with the cylinder 1 through threads.
Preferably, the outer edge of the piston 4 and the inner wall surface of the cylinder 1 are respectively supported and sealed by a first support ring 5 and a first dynamic seal 6.
Preferably, the outer edge of the piston rod 14 and the inner hole of the guide sleeve 9 are respectively supported and sealed by a second support ring 8, a second dynamic seal 12 and a dust ring 13, and the dust ring 13 is further arranged between the outer edge of the piston rod 14 and the inner hole of the guide sleeve 9.
Preferably, the cylinder body 1 and the cylinder bottom 2 are connected and fastened through welding or threaded connection, and a sealing device is installed.
Preferably, the buffer piston 7 and the piston 4 are connected and fastened through a threaded connection or welding.
Preferably, the number of the damping through holes g is 2 to 4.
Preferably, the first bearing 3 is mounted inside the bottom 2.
Preferably, the club head 16 is internally mounted with a second bearing 17.
The invention also provides application of the buffering method of the hydraulic actuating cylinder at the stroke starting end in a hydraulic system.
(III) advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) the novel internal buffer structure of the actuator cylinder is constructed, and through the organic matching of the nested piston, the slender damping orifice and the annular damping gap, oil liquid in the rodless cavity is skillfully introduced into the buffer piston, so that the piston and the piston rod generate relative motion and variable damping, and the problem that the traditional internal buffer structure is difficult to realize the buffer of the initial end of the actuator cylinder can be solved;
(2) compared with the external buffer mode of the actuating cylinder, the hydraulic actuating cylinder designed in the implementation process of the method has the advantages of simple structure, convenience in installation and maintenance, low use cost and the like.
Drawings
Fig. 1 is a schematic diagram of the main structure of a hydraulic actuator cylinder designed in the implementation process of the buffering method of the invention;
FIG. 2 is a schematic structural view of the piston rod of FIG. 1 with a buffering action at the beginning of extension;
FIG. 3 is a schematic view of the piston rod of FIG. 1 after being buffered in place during extension;
FIG. 4 is a schematic view of the piston rod of FIG. 1 after it has been extended to its position;
FIG. 5 is a schematic view of the piston rod of FIG. 1 with the retraction start of the piston rod acting as a buffer;
fig. 6 is a schematic structural view of the piston rod in fig. 1 after buffering in place during retraction.
Wherein: 1-cylinder body, 2-cylinder bottom, 3-first bearing, 4-piston, 5-first supporting ring, 6-first dynamic seal, 7-buffer piston, 8-second supporting ring, 9-guide sleeve, 10-static seal, 11-locking sleeve, 12-second dynamic seal, 13-dust ring, 14-piston rod, 15-locking nut, 16-rod head, 17-second bearing, a-first oil port, b-second oil port, c-rodless cavity, d-rod cavity, e-rodless buffer cavity, f-rod buffer cavity, g-damping through hole and h-annular damping gap.
Detailed Description
In order to make the objects, contents, and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be made in conjunction with the accompanying drawings and examples.
The invention relates to a method for buffering an actuating element which moves in a reciprocating linear mode in a hydraulic system at the stroke starting end, in particular to a method for buffering a hydraulic actuating cylinder at the stroke starting end, wherein the method can realize a buffering function at the working stroke starting end.
As shown in fig. 1 to 6, the method is based on a hydraulic ram design which is designed to essentially comprise: the structure comprises a cylinder body 1, a cylinder bottom 2, a piston 4, a buffer piston 7, a guide sleeve 9, a static seal 10, a locking sleeve 11, a dustproof ring 13, a piston rod 14, a locking nut 15, a rod head 16, bearings of different specifications, support rings, dynamic seals and the like, wherein a first oil port a and a second oil port b are respectively arranged at two ends of the cylinder body 1, the cylinder bottom 2 is installed at one side of the cylinder body 1 close to the first oil port a, and the guide sleeve 9 and the locking sleeve 11 are sequentially installed at one side of the cylinder body 1 close to the second oil port b from inside to outside; the piston 4 is positioned in the cylinder 1, the outer edge of the piston 4 is of a cylindrical structure, the interior of the piston 4 is of a blind hole-shaped structure, the bottom surface of the piston 4, the inner wall surface of the cylinder 1 and the end surface of the cylinder bottom 2 form a rodless cavity c, and the top surface of the piston 4, namely the opening end surface of the blind hole, the inner wall surface of the cylinder 1 and the end surface of the guide sleeve 9 form a rod cavity d; the outer edge of the buffering piston 7 is of a cylindrical structure, the interior of the buffering piston 7 is of a stepped hole structure, and one end, with a larger diameter, of the stepped hole of the buffering piston 7 extends into the interior of the piston 4 and is fastened with the inner wall surface of the piston 4 through threaded connection; the piston rod 14 is of a stepped shaft structure, wherein the part with the larger diameter is positioned in the buffer piston 7 and is provided with a plurality of damping through holes g along the axial direction, the bottom surface of the end with the larger diameter of the piston rod 14, the inner wall surface of the buffer piston 7 and the bottom surface of a blind hole of the piston 4 form a rodless buffer cavity e, the shaft shoulder of the stepped shaft of the piston rod 14 and the inner wall surface of the buffer piston 7 form a rod buffer cavity f, and the end with the smaller diameter of the piston rod 14 sequentially penetrates through the inner hole of the buffer piston 7, the inner hole of the guide sleeve 9 and the inner hole of the locking sleeve 11 to extend out of the end surface of the cylinder body 1 and is connected and fastened with the rod head 16 through a locking nut 15;
in the hydraulic actuating cylinder with the stroke starting end buffering function, the outer edge of the part with the smaller diameter of the piston rod 14 is in clearance fit with the inner hole of the buffering piston 7, so that an annular damping gap h is formed;
in the hydraulic actuator cylinder buffered at the stroke starting end, a first oil port a is communicated with a rodless cavity c, a second oil port b is communicated with a rod cavity d, the rod cavity d is communicated with a rod buffer cavity f through an annular damping gap h, and the rod buffer cavity f is communicated with a rodless buffer cavity e through a damping through hole g;
in the hydraulic actuator cylinder with the stroke starting end buffered, the outer edge of one end of the guide sleeve 9 extends into the cylinder body 1 and is sealed with the inner wall surface of the cylinder body 1 through the static seal 10, the end surface of the other end of the guide sleeve 9 is pressed tightly by the locking sleeve 11, and the locking sleeve 11 is connected and fastened with the cylinder body 1 through threads;
in the hydraulic actuator cylinder buffered at the stroke starting end, the outer edge of the piston 4 and the inner wall surface of the cylinder body 1 respectively realize support and dynamic seal through a first support ring 5 and a first dynamic seal 6;
in the hydraulic actuator cylinder with the stroke starting end buffered, the outer edge of a piston rod 14 and an inner hole of a guide sleeve 9 respectively realize support and dynamic seal and prevent external foreign matters from invading through a second support ring 8, a second dynamic seal 12 and a dust ring 13;
in the hydraulic actuating cylinder with the stroke starting end buffering function, the cylinder body 1 and the cylinder bottom 2 can be fixedly connected through threads and provided with a sealing device except for welding;
in the hydraulic actuating cylinder with the stroke starting end buffering function, the buffering piston 7 and the piston 4 can be connected in a threaded manner and can also be fastened by welding;
in the hydraulic actuating cylinder buffered at the stroke starting end, the number of the damping through holes g is 2-4;
in the hydraulic actuating cylinder with the stroke starting end buffering function, a first bearing 3 is arranged in a cylinder bottom 2, and a second bearing 17 is arranged in a rod head 16;
the method for buffering the hydraulic actuator cylinder at the stroke starting end based on the hydraulic actuator cylinder buffered at the stroke starting end comprises the following steps of:
as shown in fig. 1, when the actuator cylinder is in the retracted state, the piston rod 14 is in the retracted state relative to the cylinder body 1, and the piston rod 14 is in the extended state relative to the buffer piston 7, that is, the bottom surface of the piston 4 is close to the inner end surface of the cylinder bottom 2 or is in direct contact with the inner end surface, and the shoulder end surface of the piston rod 14 is close to the step end surface of the stepped hole of the buffer piston 7 or is in direct contact with the step end surface;
as shown in fig. 2, when the movable cylinder starts to extend, high-pressure oil enters the rodless cavity c from the first oil port a, and further pushes the piston 4, the buffer piston 7 and the piston rod 14 to extend outwards together, because an external load reversely pushes the piston rod 14 through the rod head 16, under the combined action of the external load and the high-pressure oil, the high-pressure oil in the rodless buffer cavity e is extruded and enters the rod buffer cavity f through the damping through hole g, then is extruded into the rod cavity d through the rod buffer cavity f through the annular damping gap h, and flows out through the second oil port b together with the oil in the rod cavity d, and in the process that the high-pressure oil firstly flows into the rod buffer cavity f and then flows into the rod cavity d through the damping through hole g and the annular damping gap h from the rodless buffer cavity e, the piston rod 14 retracts relative to the buffer piston 7, so as to play a buffering role;
as shown in fig. 3, when the movable cylinder extends for a certain distance, the high-pressure oil in the rodless buffer cavity e is completely extruded out, the bottom surface of the piston rod 14 is in contact with the end surface of the inner hole of the piston 4, and the buffering process is stopped; the ram continues to extend until the ram reaches a position where the damping piston 7 contacts the guide sleeve 9, as shown in figure 4.
As shown in fig. 4, when the actuating cylinder is in the extended state, the piston rod 14 is in the extended state relative to the cylinder body 1, and the piston rod 14 is in the retracted state relative to the buffer piston 7, that is, the buffer piston 7 is close to the guide sleeve 9 or is in direct contact with the guide sleeve 9, and the bottom surface of the piston rod 14 is close to the end surface of the inner hole of the piston 4 or is in direct contact with the end surface of the inner hole of the piston 4;
as shown in fig. 5, when the ram starts to retract, the high-pressure oil enters the rod chamber d from the second oil port b, and further pushes the piston 4, the buffer piston 7 and the piston rod 14 to perform retraction movement together, because an external load pulls the piston rod 14 through the rod head 16, under the combined action of the external load and the high-pressure oil, the high-pressure oil inside the rod buffer chamber f is extruded, one part of the high-pressure oil enters the rodless buffer chamber e through the damping through hole g, the other part of the high-pressure oil enters the rod chamber d through the annular damping gap h, and pushes the ram to retract together with the oil inside the rod chamber d, and the high-pressure oil flows into the rodless buffer chamber e from the rod buffer chamber f through the damping through hole g and flows into the rod chamber d from the rod buffer chamber f through the annular damping gap h, and the piston rod 14 performs outward extension movement relative to the buffer piston 7 to perform a buffering function;
as shown in fig. 6, after the movable cylinder retracts for a certain distance, the high-pressure oil in the rod buffer chamber f is completely squeezed into the rodless buffer chamber e and the rod chamber d, the shoulder end surface of the piston rod 14 is close to the step end surface of the stepped hole of the buffer piston 7 or the two end surfaces are in direct contact, and the buffering is stopped from this point; the ram continues to retract until the underside of the piston 4 contacts the inner end surface of the base 2 and the ram is retracted to its position as shown in figure 1.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims (9)

1. A method of cushioning a hydraulic ram at the beginning of its stroke, the method being based on the design of a hydraulic ram designed to include: the device comprises a cylinder body (1), a cylinder bottom (2), a piston (4), a buffer piston (7), a guide sleeve (9), a static seal (10), a locking sleeve (11), a dust ring (13), a piston rod (14), a locking nut (15) and a rod head (16);
the oil pump comprises a cylinder body (1), a cylinder bottom (2), a guide sleeve (9) and a locking sleeve (11), wherein a first oil port (a) and a second oil port (b) are respectively arranged at two ends of the cylinder body (1), the cylinder bottom (2) is installed at one side, close to the first oil port (a), in the cylinder body (1), and the guide sleeve and the locking sleeve are sequentially installed at one side, close to the second oil port (b), in the cylinder body (1) from inside to outside; the piston (4) is positioned in the cylinder body (1), the outer edge of the piston (4) is of a cylindrical structure, the interior of the piston (4) is of a blind hole-shaped structure, the bottom surface of the piston (4), the inner wall surface of the cylinder body (1) and the end surface of the cylinder bottom (2) form a rodless cavity (c), and the top surface of the piston (4), namely the opening end surface of the blind hole, the inner wall surface of the cylinder body (1) and the end surface of the guide sleeve (9) form a rod cavity (d); the outer edge of the buffering piston (7) is of a cylindrical structure, the interior of the buffering piston (7) is of a stepped hole structure, and one end, with a larger diameter, of the stepped hole of the buffering piston (7) extends into the interior of the piston (4) and is fixedly connected with the inner wall surface of the piston (4); the piston rod (14) is of a stepped shaft structure, wherein the part with the larger diameter is positioned in the buffer piston (7) and is provided with a plurality of damping through holes (g) along the axial direction, the bottom surface of the end with the larger diameter of the piston rod (14) and the inner wall surface of the buffer piston (7) and the bottom surface of a blind hole of the piston (4) form a rodless buffer cavity (e), the shaft shoulder of the stepped shaft of the piston rod (14) and the inner wall surface of the buffer piston (7) form a rod buffer cavity (f), and the end with the smaller diameter of the piston rod (14) sequentially penetrates through the inner hole of the buffer piston (7), the inner hole of the guide sleeve (9) and the inner hole of the locking sleeve (11) to extend out of the end surface of the cylinder body (1), is connected with the rod head (16) through threads and is connected and fastened through the locking nut (15);
in the hydraulic actuating cylinder with the stroke starting end buffered, the outer edge of the part with the smaller diameter of the piston rod (14) is in clearance fit with the inner hole of the buffer piston (7), so that an annular damping gap (h) is formed;
in the hydraulic actuating cylinder with the stroke starting end for buffering, a first oil port (a) is communicated with a rodless cavity (c), a second oil port (b) is communicated with a rod cavity (d), the rod cavity (d) is communicated with a rod buffering cavity (f) through an annular damping gap (h), and the rod buffering cavity (f) is communicated with a rodless buffering cavity (e) through a damping through hole (g);
the method for buffering the hydraulic actuator cylinder at the stroke starting end based on the hydraulic actuator cylinder comprises the following steps:
when the actuating cylinder is in a retraction state, the piston rod (14) is in a retraction state relative to the cylinder body (1), the piston rod (14) is in an extension state relative to the buffer piston (7), namely the bottom surface of the piston (4) is close to the inner end surface of the cylinder bottom (2) or the inner end surface and the inner end surface are in direct contact, and the shaft shoulder end surface of the piston rod (14) is close to the step end surface of the stepped hole of the buffer piston (7) or the step end surface and the step end surface are in direct contact;
when the movable cylinder begins to extend, oil enters the rodless cavity (c) from the first oil port (a) and further pushes the piston (4), the buffer piston (7) and the piston rod (14) to extend outwards together, an external load reversely pushes the piston rod (14) through the rod head (16), under the combined action of the external load and the oil, the oil inside the rodless buffer cavity (e) is extruded and enters the rod buffer cavity (f) through the damping through hole (g), then is extruded into the rod cavity (d) through the annular damping gap (h) by the rod buffer cavity (f), and flows out through the second oil port (b) together with the oil inside the rod cavity (d), the oil sequentially passes through the damping through hole (g) and the annular damping gap (h) and flows into the rod buffer cavity (f) from the rodless buffer cavity (e) and then flows into the rod cavity (d), and the piston rod (14) retracts relative to the buffer piston (7), the buffer function is realized;
when the actuating cylinder extends for a certain distance, all oil in the rodless buffer cavity (e) is extruded out, the bottom surface of the piston rod (14) is in contact with the end surface of the inner hole of the piston (4), and the buffering process is stopped; the actuating cylinder continues to extend until the actuating cylinder extends to the right position when the buffer piston (7) is contacted with the guide sleeve (9);
when the actuating cylinder is in an extending state, the piston rod (14) is in an extending state relative to the cylinder body (1), the piston rod (14) is in a retracting state relative to the buffer piston (7), namely the buffer piston (7) is close to the guide sleeve (9) or the guide sleeve and the guide sleeve are in direct contact, and the bottom surface of the piston rod (14) is close to the end surface of the inner hole of the piston (4) or the guide sleeve and the guide sleeve are in direct contact;
when the movable cylinder starts to retract, oil enters the rod cavity (d) from the second oil port (b) and further pushes the piston (4), the buffer piston (7) and the piston rod (14) to retract together, an external load pulls the piston rod (14) through the rod head (16), under the combined action of the external load and the oil, the oil in the rod buffer cavity (f) is extruded, one part of the oil enters the rodless buffer cavity (e) through the damping through hole (g), the other part of the oil enters the rod cavity (d) through the annular damping gap (h) and pushes the movable cylinder to retract together with the oil in the rod cavity (d), the oil flows into the rodless buffer cavity (e) from the rod buffer cavity (f) through the damping through hole (g) and flows into the rod cavity (d) from the rod buffer cavity (f) through the annular damping gap (h), and the piston rod (14) extends relative to the buffer piston (7), the buffer function is realized;
after the actuating cylinder retracts for a certain distance, all oil in the rod buffer cavity (f) is extruded into the rodless buffer cavity (e) and the rod cavity (d), the shaft shoulder end surface of the piston rod (14) is close to the step end surface of the stepped hole of the buffer piston (7) or two end surfaces are in direct contact, and the buffering is stopped from this point; the actuator cylinder continues to retract until the bottom surface of the piston (4) contacts the inner end surface of the cylinder bottom (2) and the actuator cylinder retracts to the position.
2. A method for buffering a hydraulic actuator cylinder at the beginning of a stroke according to claim 1, wherein the outer edge of one end of the guide sleeve (9) extends into the cylinder (1) and is sealed with the inner wall surface of the cylinder (1) through a static seal (10), the end surface of the other end of the guide sleeve (9) is pressed by a locking sleeve (11), and the locking sleeve (11) is connected and fastened with the cylinder (1) through threads.
3. A method of damping a hydraulic ram at the beginning of its stroke as claimed in claim 1, wherein the outer edge of the piston (4) and the inner wall of the cylinder (1) are supported and sealed by a first support ring (5) and a first dynamic seal (6), respectively.
4. A method of damping a hydraulic ram at the beginning of its stroke as claimed in claim 1, wherein the cylinder (1) is secured to the cylinder bottom (2) by welding or screwing and a sealing means is installed.
5. A method of damping a hydraulic ram at the beginning of its stroke as claimed in claim 1, wherein the damping piston (7) is screwed or welded to the piston (4).
6. A method of damping a hydraulic ram at the beginning of its stroke as claimed in claim 1 wherein the number of damping through holes (g) is 2-4.
7. A method of damping a hydraulic ram at the beginning of its stroke as claimed in claim 1 characterised in that the first bearing (3) is mounted within the base (2).
8. A method of damping a hydraulic ram as claimed in any one of claims 1 to 7 in which the head (16) internally houses a second bearing (17).
9. Use of a method of damping the beginning of a stroke of a hydraulic ram as claimed in any one of claims 1 to 8 in a hydraulic system.
CN202010447403.6A 2020-05-25 2020-05-25 Buffering method of hydraulic actuating cylinder at stroke starting end Active CN111577702B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2950173B2 (en) * 1994-11-04 1999-09-20 トヨタ車体株式会社 Single acting hydraulic cylinder
GB0501893D0 (en) * 2005-01-29 2005-03-09 Goodrich Actuation Systems Ltd Linear hydraulic actuator
CN104564908A (en) * 2014-12-31 2015-04-29 中船重工中南装备有限责任公司 Buffer hydraulic cylinder
CN209654350U (en) * 2019-03-29 2019-11-19 广东南曦液压机械有限公司 A kind of piston type buffering hydraulic oil cylinder
CN109958671A (en) * 2019-04-26 2019-07-02 上海振华重工(集团)股份有限公司 A kind of cushion cylinder to land on cone for trestle

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