Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B7/00—Piston machines or pumps characterised by having positively-driven valving
  • F04B7/04—Piston machines or pumps characterised by having positively-driven valving in which the valving is performed by pistons and cylinders coacting to open and close intake or outlet ports
• • 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
  • F15B15/222—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having a piston with a piston extension or piston recess which throttles the main fluid outlet as the piston approaches its end position

Definitions

• the present invention relates to the field of hydraulic technology, and more particularly to a hydraulic cylinder.
• the present invention also provides a rod end cap related device for the above hydraulic cylinder, and a hydraulic buffer system using the hydraulic cylinder, an excavator and a concrete pump truck using the hydraulic cylinder. Background technique
• Hydraulic cylinders are widely used components in construction machinery. During their operation, the pistons need to continuously reciprocate. When the piston rod is extended to the extreme position, the end face of the piston will have a large impact on the end cap, which may cause damage to the hydraulic cylinder. To this end, it is necessary to provide a cushioning device at the portion to avoid damage to the hydraulic cylinder caused by the above impact.
• the existing buffer device has a large area depending on the application and size of the hydraulic cylinder.
• Another small cylinder can directly use the compression spring as a buffer device.
• the compression spring will have difficulty in obtaining a spring that is sufficiently elastic, and because of its high pressure, the spring will soon be damaged by repeated compression. Therefore, for hydraulic cylinders with large bore and large stroke, the hydraulic buffer mechanism shown in Figure 1 is usually used.
• the buffer device includes a large buffer ring 06 installed on an intermediate ring groove opened at a buffer position of a piston rod, and a large buffer sleeve 04 sleeved at a buffer position;
• the large buffer sleeve 04 is provided with a buffer inner hole 07 having an inner diameter matching the outer diameter of the large buffer sleeve 04 at the cover portion of the rod end cover 01 of the cylinder.
• the large buffer sleeve 04 When the piston rod is extended, the large buffer sleeve 04 is first inserted into the buffer inner hole 07, so that the oil return passage of the rod chamber in the cylinder 02 is blocked, and at the same time, the large buffer The gap between the sleeve 04 and the buffer inner bore 07 forms a throttle oil passage; thus, the piston 05 can continue to move in the projecting direction while being subjected to the throttle throttle damping effect, and its moving speed is lowered.
• the above buffer mechanism is widely used in hydraulic cylinders with large bore and large stroke to provide better buffer protection for hydraulic cylinders.
• hydraulic cylinders often operate under high-load, high-frequency operating conditions.
• a driving cylinder used for driving an excavator arm of an excavator.
• the large buffer sleeve 04 in the above-mentioned buffer mechanism needs to be repeatedly inserted into the buffer inner hole 07 at a high speed, and the fitting gap between the two is originally very small, and the piston rod 03 is heavy, in gravity It is easy to tilt to one side under the action; therefore, the hydraulic cylinder used in the above case is prone to failure of the buffer mechanism in which the buffer sleeve 04 cannot be inserted into the buffer inner hole 07, and the entire hydraulic cylinder cannot be used normally.
• the invention provides a hydraulic cylinder, wherein the buffer mechanism of the hydraulic cylinder can reliably achieve a buffering effect under a large load and a high frequency working condition, and has a longer service life. Moreover, the hydraulic cylinder has low manufacturing precision requirements and is convenient for tissue production. This hydraulic cylinder is especially suitable for the manufacture of large bore and long stroke hydraulic cylinders.
• the present invention also provides the above-described hydraulic cylinder related apparatus including the piston rod, the rod end cover and the cushion sleeve used therefor.
• the present invention also provides a hydraulic buffer system using the above hydraulic cylinder.
• the present invention also provides an excavator using the above hydraulic cylinder.
• the present invention also provides a concrete pump truck using the above hydraulic cylinder.
• the hydraulic cylinder provided by the invention has a buffer sleeve which can slide along the axial direction of the piston rod in a buffer position of the piston rod in the rod cavity, and an end surface of the buffer sleeve away from the piston side is called a buffer sleeve.
• the inner cylinder chamber is provided with a rod cavity sealing end surface capable of blocking the buffer sleeve and capable of engaging with the first end surface of the buffer sleeve to form a sealing surface; and at least one throttle oil passage is provided for extending the piston rod
• the first end surface of the buffer sleeve is adhered to the closed end surface of the rod cavity, the sealing surface is formed, and when the piston reaches the end position of the extending motion, the sealing surface is close to the piston side. Hydraulic oil can flow through the throttle passage to the rod cavity through the oil hole.
• the throttle oil passage is linearly disposed between the piston rod and the buffer sleeve in the axial direction.
• one end of the throttle oil passage near the piston is referred to as a first end
• an end adjacent to the oil passage hole having a rod cavity is referred to as a second end
• a cross-sectional area of the throttle oil passage is from the first end to the first end
• the buffer sleeve is spaced from the end of its sliding direction toward the piston.
• the axial action area of the hydraulic oil on the sealing surface near the piston side is greater than that of the buffer sleeve.
• the piston rod is provided with a buffering stop shoulder, and when the buffer sleeve is not blocked by the closed end surface of the rod cavity, the first end surface of the buffer sleeve functions as a resilient elastic element. Lower against the shoulder of the buffer.
• a piston blocking shoulder that allows the buffer sleeve to pass but is capable of blocking the piston in this position is provided.
• the first end surface of the buffer sleeve is adhered to the sealed end surface of the rod cavity to form a surface seal or a line seal.
• the main body of the throttle oil passage is a throttle groove axially disposed on the surface of the piston rod.
• the cross-sectional area of the throttle groove decreases.
• the buffering shoulder is provided with an oil discharging groove, and the oil discharging groove is disposed corresponding to the end point of the throttle groove.
• the throttle oil passage comprises two sections, adjacent to the front section of the piston, the main body of which is a throttle groove axially disposed on the surface of the piston rod, and the main body of the rear section adjacent to the oil passage hole of the rod cavity is the central shaft of the piston rod To the extended dark oil passage.
• the throttle oil passage comprises a dark oil passage extending axially in the piston rod, and a plurality of oil-saving holes communicating with the piston rod surface and the dark oil passage, the oil inlet holes being axially distributed along the surface of the piston rod, And the closer to the oil-saving hole of the dark oil passage outlet, the larger the aperture; the second end of the throttle oil passage is the dark oil passage outlet, and the fuel-saving hole is the first end of the throttle oil passage.
• the throttle body is a chamfered surface disposed axially on a surface of the piston rod.
• a transition sleeve is provided in the cushioning position to cooperate with the piston rod, and the throttle oil passage is disposed on the transition sleeve.
• the transition sleeve is provided with one or several annular grooves as the balance groove; the cross section of the annular groove may be V-shaped, U-shaped or square or other cross-section.
• the closed cavity end surface of the rod cavity is disposed on the rod end cover.
• the piston blocking shoulder is an end surface of the rod end cap.
• the invention also provides a related device of a hydraulic cylinder, in particular to a piston rod, the piston rod is provided with a buffering stop shoulder at a starting point of the buffering position, and at least one axially extending throttle oil passage is arranged along the surface of the piston rod.
• One end of the throttle oil passage is close to the position of the rod end face of the piston after the piston is installed, which is called the first end; the other end is at the side of the buffer position of the shoulder relief groove, which is called the second end.
• the cross-sectional area of the throttle oil passage gradually increases from the first end to the second end.
• the throttling oil passage body is a throttle groove extending axially on a surface of the piston rod; the cross-sectional area of the throttle oil passage is gradually increased from the first end to the second end, specifically by throttling The depth of the groove is gradually increased to achieve.
• the buffer position of the piston rod is provided with a plurality of annular grooves as balance oil grooves.
• the invention also provides another related device of the hydraulic cylinder, in particular to a rod end cover, the rod end cover is provided with a rod cavity oil passage hole and a rod from the top end thereof to the rod chamber end cover cover.
• the closed end surface of the cavity is a stepped surface of the closed cavity which is disposed in the inner cavity of the rod end cover.
• the cap having the rod end cap serves as the piston blocking shoulder.
• the invention also provides a related device of a hydraulic cylinder, in particular a buffer sleeve, outside the buffer sleeve
• the diameter is smaller than the inner diameter of the cylinder of the working hydraulic cylinder, and the inner diameter of the cylinder can be sleeved on the piston rod buffer position and axially free to slide; the structure of the first end surface away from the piston side when installed enables the end surface to be coupled with the cylinder
• the sealed end surface of the cavity between the rod cavity oil passage hole and the piston rod extending end position is formed to form a sealing surface.
• the end surface opposite to the first end surface of the buffer sleeve is provided with a central boss that cooperates with the compression spring.
• the present invention also provides a hydraulic buffer system comprising the hydraulic cylinder of any one of the above aspects.
• the present invention also provides an excavator using at least one of the hydraulic cylinders described in any one of the above aspects.
• the present invention also provides a concrete pump truck that uses at least one of the hydraulic cylinders described in any one of the above aspects.
• the hydraulic cylinder provided by the invention has a first end face of the buffer sleeve which can cooperate with a closed cavity end surface of the cylinder cavity disposed in the cylinder cavity on the side of the rod cavity when the piston rod is extended to reach the buffer position to form the partition oil.
• the sealing surface of the road, the sealing surface divides the rod cavity into two cavities, wherein the cavity on the side of the sealing surface on the side of the piston is called a buffer oil chamber; the other cavity is located on the sealing surface and has a rod cavity.
• the hydraulic oil in the buffer oil chamber has a large oil pressure under the push of the piston, and the first end surface of the buffer sleeve can be firmly pressed on the closed end surface of the rod cavity to make the two fit.
• the sealing surface of the formed sealing surface is more secure; the cylinder is further provided with a throttle oil passage, the throttle oil passage is formed on the sealing surface, and the time until the piston reaches the end position of the extending motion
• the oil passage in the buffer oil chamber is supplied to the oil passage on the side of the rod chamber through the oil hole.
• the hydraulic oil can only flow through the throttle passage to the oil passage hole of the rod chamber, and the oil passage of the throttle oil passage is narrow, and the hydraulic oil passage capacity is limited, so that the piston movement is inevitable. It is greatly resisted and acts as a buffer.
• the throttling oil passage is linearly disposed between the piston rod and the buffer sleeve in the axial direction, and the structure can smoothly and directly drain the hydraulic oil in the buffer oil chamber to the rod cavity.
• the throttle oil passage can be formed to avoid the jam in the buffering process.
• the cross-sectional area of the throttle oil passage can be changed as needed, specifically, the cross-sectional area near one end of the piston is small, and the cross-sectional area near the end of the rod-shaped oil passage hole is large.
• the throttle body is a throttle groove axially disposed on a surface of the piston rod, and a cross-sectional area of the throttle groove gradually increases from the first end to the second end.
• a plurality of annular grooves are provided on the outer diameter surface of the piston rod or the inner diameter surface of the buffer sleeve as a balance oil groove, and the balance oil groove can be combined with the throttle groove Cooperating, the hydraulic oil is uniformly distributed on the inner diameter surface of the buffer sleeve, so that the first end surface of the buffer sleeve and the closed end surface of the rod cavity are not inclined when the sealing end surface is fitted, so that the sealing surface is firm.
• the following condition is required: when the first end surface of the buffer sleeve contacts the closed end surface of the rod cavity to form a sealing surface, the hydraulic oil pair of the sealing surface is close to the piston side
• the axial acting area of the buffer sleeve is greater than the axial acting area of the hydraulic oil on the side of the rod chamber through the oil hole.
• the oil pressure on both sides of the sealing surface is substantially the same, and the first end surface of the buffer sleeve abuts against the closed end surface of the rod cavity at a certain speed, which may not be compacted at this moment. , affects the smoothness of the buffer at this point in time.
• the oil pressure on the side of the sealing surface close to the piston is multiplied by the axial acting area of the buffer sleeve at this end to obtain the total pressure VI, and the oil pressure on the side of the sealing surface near the oil outlet of the rod cavity is multiplied by The area of the buffer sleeve at this end obtains the total pressure V2; since the oil pressure on both sides of the sealing surface is the same at the moment of forming the sealing surface, the total pressure on the larger side is larger, that is, V1>V2,
• the buffer sleeve is compacted on the closed end surface of the rod cavity to ensure smoothness of the buffering process.
• the invention also provides a piston rod, a rod end cover and a large buffer sleeve for the above hydraulic cylinder Such parts are specially designed to achieve the above buffer mechanism.
• the present invention also provides a cushioning system using the above-described hydraulic cylinder, and a hydraulic cushioning system using the hydraulic cylinder can obtain a good and stable cushioning effect.
• the present invention also provides an excavator and concrete pump truck using the above hydraulic cylinder, and by using the above hydraulic cylinder, the excavator and the concrete pump truck can obtain longer trouble-free use time.
• 1 is a hydraulic cylinder of a cushioning mechanism in the form of a buffer sleeve inserted into a buffer bore in the prior art
• FIG. 2 is a mechanical structural view of a hydraulic cylinder provided by a first embodiment of the present invention
• Figure 3 is a partial view of a piston rod according to a first embodiment of the present invention.
• Figure 4 is a view taken along the line A-A of the piston rod 3;
• Figure 5 is a C-C sectional view of the piston rod 3;
• Figure 6 is a view showing a state in which the hydraulic cylinder of the first embodiment of the present invention is in a position where the sealing surface starts to form;
• Figure 7 is a view showing the state of the hydraulic cylinder of the first embodiment of the present invention when the piston is moved to the end position;
• Figure 8 is a mechanical structural view of a hydraulic cylinder provided by a second embodiment of the present invention.
• Figure 9 is a partial view of a transition sleeve used in a second embodiment of the present invention.
• Figure 10 is a view showing a part of a cushion sleeve provided with a balance oil groove on an inner diameter surface of a second embodiment of the present invention.
• Figure 11 is a schematic view of a throttle oil passage in a buffer mechanism provided with a transition sleeve
• FIG. 12 is a schematic view of another throttle oil passage suitable for use in a buffer mechanism provided with a transition sleeve;
• Figure 13 is a schematic illustration of a throttled oil passage in a buffer mechanism that is not provided with a transition sleeve.
• a first embodiment of the present invention provides a hydraulic oil cylinder, which is provided on a side of a rod cavity thereof There is a buffer device.
• FIG. 2 is a mechanical structural view of a hydraulic cylinder provided by a first embodiment of the present invention.
• the hydraulic cylinder includes a rod end cover 1, a cylinder 2, a piston rod 3, a buffer sleeve 4, a spring 5, a piston 6, and the like.
• the cylinder 2 provides a space for the hydraulic cylinder to seal hydraulic oil, and the inner cavity of the cylinder 2 is divided into a rod chamber 2-1 and a rodless chamber 2 by a piston 6 that is axially movable along the inner chamber. -2, the cavity in which the piston rod 3 is located has a rod cavity 2-1.
• the outer diameter surface of the piston 6 is matched with the inner diameter surface of the cylinder tube 2, and a plurality of sealing rings are disposed on the outer diameter surface, so that the hydraulic oil having the rod chamber 2-1 and the rodless chamber 2-2 is Completely isolated from each other.
• the rod end cap 1 seals the cylinder barrel 2 at the end of the cylinder barrel 2 having the rod chamber 2-1 side, and the rod chamber end cover 1 is provided with a rod cavity oil
• the hole 1-1, the rod-shaped oil-passing hole 1-1 is connected to the oil pipe, and provides a passage for the hydraulic oil in the inner cavity of the cylinder 2 to enter and exit the rod-cavity 2-1.
• the passage of hydraulic oil into and out of the rodless chamber 2-2 is provided by a rodless cavity oil passage provided in the rodless chamber end cap of the cylinder 2. This embodiment only describes the cushioning device on the side of the rod cavity, and does not relate to the case of the rodless chamber 2-2.
• the buffer mechanism of the hydraulic cylinder includes a cushion sleeve 4, a spring 5, and a structure in which a piston mechanism is formed on the piston 6, the piston rod 3, and the rod end cover 1.
• the buffer sleeve 4 is sleeved on the piston rod 3 in the buffer position of the rod chamber 2-1.
• the buffer position refers to a section of the piston rod 3 having a specific length from the end face of the piston 6 on the side of the rod chamber 2-1, and the rod section must be buffered to avoid the piston 6
• the rod end cap 1 is damaged by direct impact.
• This range of position is the extent to which the buffer sleeve 4 slides over the piston rod 3.
• the inner diameter of the buffer sleeve 4 is such that it can slide axially on the piston rod 3, and the gap between the two is small; the outer diameter of the buffer sleeve 4 is significantly smaller than the inner diameter of the cylinder 2, and the length thereof is Part of the length of the buffer bit.
• the end face of the buffer sleeve 4 facing the end of the cylinder, that is, the side of the rod end cover 1, is a plane having a chamfered outer edge, and the plane is referred to as a first end face 4-1 of the cushion sleeve.
• the other end of the buffer sleeve 4 is referred to as a buffer sleeve second end face 4-2, and a boss 4-3 for fixing the spring 5 is provided.
• the design of the buffer sleeve needs to be preferably It is ensured that when the first end surface of the buffer sleeve is in contact with the closed end surface of the rod cavity to form a sealing surface, the axial acting area of the hydraulic oil on the sealing surface close to the piston side to the buffer sleeve It is larger than the axial acting area of the hydraulic oil on the side of the oil passage hole near the rod cavity.
• the hydraulic oil axial acting area is significantly smaller than the other end surface.
• the spring 5 is a compression spring having a compressive tension, and the spring 5 is sleeved on the piston rod 3, and its bottom end is placed on the end surface of the piston 6 on the side of the rod chamber 2-1, and the piston 6 is on the end surface.
• a spring boss is provided to fix the spring.
• the end of the spring 5 bears against the boss 4-3 of the cushion sleeve 4.
• the spring 5 is supported by the end surface of the piston 6 to elastically withstand the buffer sleeve 4, so that the buffer sleeve 4 has the first end surface of the buffer sleeve 4 when the piston 6 does not move to the buffer position. 1 against the buffering shoulder 3-4 of the piston rod 3.
• the spring 5 has a spring force sufficient to enable the cushion sleeve 4 to be held against the buffer shoulder 3-4 when it is unblocked, i.e., the spring 5 functions primarily as a resetting action.
• the rod cavity end cover 1 is provided with a rod cavity oil passage hole 1-1 and a rod cavity sealing end surface 1-2 from the top of the cover to the cover.
• the rod cavity sealing end surface 1-2 is a completely annular step surface provided in the inner cavity of the rod end cap 1, and the step surface faces the piston 6.
• the rod-cavity sealing end surface 1-2 can cooperate with the first end surface 4-1 of the cushion sleeve to form a sealing surface for blocking the hydraulic oil in the rod chamber 2-1 after the start of the buffering.
• the rod end cap 1 further has a buffer sleeve passage section 1-3 extending from the rod cavity closed end surface 1-2 toward the piston 6, and the buffer sleeve passes through the cavity inner diameter ratio of the section 1-3
• the inner diameter of the cavity at the position where the cavity sealing end face 1-2 is located is large, but smaller than the inner diameter of the cylinder tube 2 where the piston 6 is located, and the inner diameter of the cavity of the buffer sleeve passing through the segment 1-3 is larger than the outer diameter of the buffer sleeve 4 , so that the buffer sleeve 4 can smoothly enter the segment.
• the end face of the cap end of the rod end cap 1 abuts against the inner wall surface of the cylinder barrel to form a piston blocking shoulder 1-4 capable of positioning the end point of the movement of the piston 6.
• the structure of the piston rod 3 is more related to the buffer mechanism, and in addition to the above-mentioned buffer position related to the installation of the buffer sleeve 4 and the buffer position shoulder 3-4, a throttle groove is also provided. Balance oil grooves, oil drain grooves, etc., are described in detail below.
• Figure 3 which is a part drawing of the piston rod 3; please also refer to Figure 4, which is the A-A direction view of the piston rod 3; please also refer to Figure 5, which is a C-C sectional view of the piston rod 3.
• At least one throttle oil passage is provided on the piston rod 3, and the main body thereof is an orifice groove 3-1 extending in the axial direction on the outer diameter surface of the piston rod 3.
• the throttle groove 3-1 is arranged on the piston rod, and its starting point is called At the position close to the end face of the piston having the cavity, the end point (referred to as the second end) reaches the undercut side wall of the buffer shoulder 3-4 of the piston rod 3.
• the position of the first end near the end face of the piston having the rod cavity is relative to the end point thereof; in fact, the starting point position of the throttle groove 3-1 needs to be matched according to the end position of the extension movement of the piston 6.
• the first end has been completely shielded by the buffer sleeve 4 before the piston 6 reaches the end position.
• an oil discharge groove 3-3 is disposed on the buffer position shoulder 3-4.
• the oil discharge groove 3-3 The position is just aligned with the outlet of the throttle groove 3-1, and there are four oil discharge grooves 3-3 corresponding to the four throttle grooves 3-1.
• the oil discharge grooves 3-3 provide an outlet passage for the hydraulic oil flowing out from the outlet of the throttle groove 3-1, which can make the flow of the hydraulic oil flowing out of the throttle groove 3-1 during the buffering process more stable.
• the outlet of the hydraulic oil can be provided at the moment when the first end surface 4-1 of the buffer sleeve and the sealed end surface of the rod cavity are just attached, so as to avoid a sudden increase of the hydraulic damping and ensure stable operation.
• balance oil grooves 3-2 In the buffer position of the piston rod 3, a plurality of circumferential grooves are also arranged on the circumferential surface of the piston rod 3, and these annular grooves are referred to as balance oil grooves 3-2.
• These balancing oil grooves 3-2 may have a U-shaped, V-shaped or square bottom, and other forms, as determined, and the depth may be determined experimentally as needed.
• the function of these balance oil grooves 3-2 is to achieve oil pressure balance when the throttle groove 3-1 is discharged, and to prevent the buffer sleeve 4 from tilting under the unbalanced oil pressure, resulting in sealing of the sealing surface during buffering. Not strict.
• Figure 2 is the case when the piston 6 has not reached the buffer position; please also refer to Figure 6, which shows the situation at the beginning of the buffering process; please also refer to Figure 7, which shows the situation at the end of the buffering process. .
• the oil passage of the hydraulic oil in the rod chamber 2-1 is partially blocked as the buffer sleeve 4 enters the buffer sleeve through the section 1-3, and the hydraulic oil can only pass through the buffer sleeve 4 and the buffer sleeve Through the gap between the segments 1-3, the oil passage damping effect of the piston 6 is obviously increased to the rod-shaped oil passage hole 1-1; as the buffer sleeve 4 gradually penetrates the buffer sleeve through the segment 1 -3, the degree of blockage of the hydraulic oil passage is gradually increased, and the hydraulic damping of the piston 6 is gradually increased until the buffer sleeve 4 completely enters the buffer sleeve through the section 1-3, and the damping effect of the oil passage is substantially not Changing platform period.
• the first end surface 4-1 of the cushion sleeve gradually approaches the rod-shaped closed end surface 1-2 of the rod end cover 1.
• the first end surface 4-1 of the buffer sleeve abuts against the rod-shaped closed end surface 1-2 of the rod end cover 1, and the two end surfaces are fitted to each other.
• the oil pressure on both sides of the sealing surface is substantially the same, and the first end surface 4-1 of the buffer sleeve abuts against the closed end surface 1-2 of the rod cavity at a certain speed, and may not be pressed at this moment. Really, affecting the smoothness of the buffer at this point in time. For this reason, in the design, the following conditions are ensured: When the first end surface 4-1 of the buffer sleeve contacts the rod cavity sealing end surface 1-2 to form a sealing surface, the sealing surface is close to the piston side.
• the axial acting area of the hydraulic oil to the buffer sleeve is greater than the axial acting area of the hydraulic oil on the side of the rod chamber through the oil hole to the buffer sleeve.
• the area of both end faces of the cushion sleeve 4 is uniform, but after the sealing surface is formed, the above condition is established because the first end surface 4-1 is partially shielded. After the above conditions are satisfied, the oil pressure on the side of the sealing surface close to the piston is multiplied by the axial acting area of the buffer sleeve at this end to obtain the total pressure VI, and the oil pressure on the side of the sealing surface near the oil outlet of the rod cavity is multiplied by the pressure.
• the area of the punch sleeve at this end obtains the total pressure V2; since the oil pressure on both sides of the sealing surface is the same at the moment of forming the sealing surface, the total pressure on the larger side is larger, that is, V1>V2, thus,
• the buffer sleeve is compacted on the closed cavity end surface 1-2 of the rod cavity to ensure the smoothness of the sealing surface establishing process.
• the buffer sleeve 4 and the rod end cover 1 are equivalent to form a one-way valve, and the oil passage is blocked.
• the hydraulic oil having the rod cavity is divided into two cavities by the sealing surface, wherein the piston 6 is the buffer oil chamber T, and the hydraulic oil in the buffer oil chamber T is pushed by the piston 6.
• the hydraulic oil can only flow through the throttle groove 3-1 to the side of the rod-shaped oil passage hole 1-1 of the above-mentioned closed surface.
• the depth of the throttle groove 3-1 is relatively deep on the second end side, that is, the flow passage capacity of the throttle groove 3-1 is high, and the flow through the throttle groove 3-1 is made.
• the hydraulic oil is relatively more.
• the sealing surface moves rearward relative to the piston rod 3, and the depth of the throttle groove 3-1 connecting the two sides of the sealing surface becomes shallower, resulting in the flow of the throttle groove 3-1.
• the passing ability is gradually reduced.
• the hydraulic oil passes through the throttle groove 3-1, and the balance oil groove 3-2 is filled on the shaft section where the buffer sleeve is located, so that the oil pressure of the buffer sleeve is circumferentially
• the balance of each position ensures that the buffer sleeve 4 is not deflected, and the sealing effect of the sealing surface is ensured.
• the piston 6 After reaching the position shown in FIG. 7, the piston 6 is blocked by the piston blocking shoulder 1-4 formed by the end surface of the rod end cover 1 having the rod end cover opening end, and the piston rod 3 reaches its extended end position.
• the first end of the throttle groove 3-1 has entered the buffer sleeve 4 at this time, the throttle oil passage is closed, and the buffering process ends.
• the second end surface of the buffer sleeve 4 and the rod end surface of the piston 6 still have a spacing L, which ensures that the buffer sleeve 4 does not The normal movement of the piston 6 is blocked.
• This spacing L is the distance L of the end of the buffer sleeve from its end in the direction of the piston when the piston rod projects to the end of the stroke.
• the first end surface 4-1 of the buffer sleeve 4 is separated from the sealed end surface 1-2 of the rod cavity 1, and at this time, the buffer sleeve 4 interacts with the rod end cover 1 during the retraction of the piston rod 3 Check valve Function.
• the larger the L the larger the separation distance between the first end face 4-1 of the cushion sleeve 4 and the closed end face 1-2 of the rod end cap 1, and the greater the flow of hydraulic oil into the rod cavity.
• the smaller the L1 is, the smaller the separation distance between the first end surface 4-1 of the buffer sleeve 4-1 and the closed end surface 1-2 of the rod end cover 1, and the smaller the flow rate of the hydraulic oil entering the rod chamber.
• the damping effect of the hydraulic oil from the buffer sleeve 4 into the buffer sleeve of the rod end cover 1 starts from the section 1-3, and gradually increases; in particular, through the throttle groove 3-
• the depth change of 1 gradually increases the throttling capacity, and the hydraulic damping gradually increases, so that the speed before the piston 6 reaches the end position gradually decreases.
• the gap forms an oil passage, so that the hydraulic damping is gradually increased throughout the buffering process, and the impact on the rod end cap 1 and the cylinder barrel 2 is avoided.
• the curve of the throttling ability of the throttle groove 3-1 can be controlled to control the curve of the throttling ability, thereby ensuring that the piston 6 can obtain a very smooth buffering process.
• the balance oil groove may be disposed not on the piston rod 3 but on the inner diameter surface of the cushion sleeve 4, and the effect is the same as that provided on the piston rod 3.
• Fig. 10 shows a buffer sleeve 4 provided with a balance oil groove 4-4 on the inner diameter surface.
• the balance oil groove 3-2 may not actually be in the form of an annular groove, for example, a thread groove may be used, but the annular groove used in the embodiment is preferred because it is convenient to process and has better Balance effect.
• the passages for forming the sealing surfaces to connect the chambers on both sides of the sealing surface are collectively referred to as a throttle oil passage.
• the main body of the throttle oil passage is the throttle groove, but at different times The composition of the throttle oil passage is also different.
• the oil discharge groove 3-3 provided on the shoulder corresponding to the throttle groove bears the role of the second end port of the throttle passage, and plays an important role in smoothing the buffering process.
• the gap between the buffer sleeve 4 and the piston rod 3 also forms part of the throttle oil passage.
• the second end of the throttle oil passage is disposed on the side wall of the buffering shoulder. In fact, as long as the piston reaches the end position, the second end of the throttle oil passage is in the inner cavity of the hydraulic cylinder. can.
• the closed end surface of the rod cavity and the first end surface of the buffer sleeve are formed into a plane sealing surface in the form of a surface contact.
• the closed end surface of the rod cavity and the buffer sleeve may be The end face is designed correspondingly, and the sealing surface formed by the two faces is a flat seal or a face seal such as a cone seal or a curved seal, or a wire seal form.
• a second embodiment of the present invention provides a hydraulic cylinder that is provided with a cushioning device on a side of the rod chamber.
• This embodiment is basically the same as the first embodiment described above, but the transition sleeve 12 is fitted over the buffer position of the piston rod 3.
• FIG. 8 is a hydraulic cylinder provided by a second embodiment of the present invention.
• This embodiment is slightly modified on the basis of the first embodiment, and in the following description, the same portions as those of the first embodiment are denoted by the same icons.
• the hydraulic cylinder is provided with a transition sleeve 12 at the buffering position of the piston rod 3, the radial length of which is at least sufficient to occupy most of the length of the buffering position, the inner diameter of which makes it and the piston rod
• the outer diameter of the buffer position of 3 is matched so that it fits tightly on the buffer position of the piston rod 3.
• the part of the transition sleeve 12 is shown in Figure 9.
• the outer diameter surface of the transition sleeve 12 is provided with an axially extending throttle groove 12-1, the depth of the throttle groove 12-1 being close to the rear end of the transition sleeve 12 near the piston.
• the front end of the rod cavity oil inlet hole is gradually deepened; the first end of the throttle groove 12-1 is located near the rear end surface of the transition sleeve 12, and the second end is at the front end surface of the transition sleeve 12.
• On the outer diameter surface of the transition sleeve 12 a total of four of the throttle grooves 12-1 are arranged uniformly to form a throttle passage.
• a plurality of annular grooves are provided on the outer diameter surface of the transition sleeve 12 as the balance oil grooves 12-4.
• the balance oil groove may not be disposed on the transition sleeve 12, but on the inner diameter surface of the buffer sleeve 4, and the effect is the same as that provided on the piston sleeve 12.
• Fig. 10 shows a buffer sleeve 4 provided with a balance oil groove on the inner diameter surface.
• the working process of the hydraulic cylinder is the same as that of the first embodiment described above, and details are not described herein again.
• the second embodiment has the advantage that, after the technical solution, it is no longer necessary to machine the axially extending throttle groove at the buffer position of the piston rod 3, and the piston rod 3 is processed on the surface due to its long length. A throttle groove with a high precision requirement is difficult. Processing the throttle groove 12-1 on the short length transition sleeve 12 is relatively simple and convenient.
• the structure and size of the throttle groove are actually variously selected.
• the throttle groove with different size and structure can be selected by changing the piston sleeve to flexibly meet the buffer requirement.
• the main body of the throttle oil passage is a throttle groove.
• the throttle oil passage can be selected from other structural forms. For details, refer to FIG. 11 to FIG.
• FIG 11 shows a throttle throttle form that is more suitable for use in a buffer mechanism provided with a transition sleeve.
• the throttle oil passage comprises two sections, the front section near the first end is a throttle groove 12-1 axially disposed on the surface of the transition sleeve 12, and the rear section near the second end is a dark oil passage extending axially in the transition sleeve. 12-2, this can also play a role in throttling.
• the section of the throttle groove 12-1 may also be provided in a form of gradually deepening from the first end to the second end to provide a smooth cushioning effect.
• Figure 12 shows another form of throttling oil passage that is more suitable for use in a buffer mechanism provided with a transition sleeve.
• the throttle oil passage includes a dark oil passage 12-2 extending axially in the transition sleeve 12, and a plurality of oil-saving holes 12-3 communicating with the piston rod surface and the dark oil passage, the oil-saving hole edge
• the piston rod surface is axially distributed, and the closer to the oil-saving hole at the front end surface of the transition sleeve 12, the larger the aperture; thus, as the buffer sleeve slides on the piston rod, the closer the piston rod 3 is to the extended end position, The smaller the discharge capacity, the greater the hydraulic damping effect, the lower the piston speed and the smoother buffering process.
• FIG. 13 shows another form of throttled oil passage.
• the throttle passage is a chamfered surface 3-5 axially disposed on the surface of the piston rod 3.
• the chamfered surface 3-5 is inclined from the portion close to the piston to the position of the buffer shoulder 3-4, and one or more of the chamfered surfaces may be provided.
• the hydraulic oil can flow out through the chamfer surface 3-5 to form a throttle oil passage.
• the use of the chamfered surface 3-5 as the throttle oil passage can also make the piston rod 3 closer to the end point, the smaller the discharge capacity, the greater the hydraulic damping effect, and the lower the speed of the piston 6 is obtained. Smooth buffering process.
• An embodiment of the hydraulic buffer system of the present invention can be obtained by using the hydraulic cylinder provided by the present invention in a hydraulic buffer system instead of the existing cylinder.
• the hydraulic cylinder provided by the present invention is used for an excavator, and the excavator of the present invention can be obtained.
• the hydraulic cylinder provided by the present invention is applied to a concrete pump truck to obtain an embodiment of the concrete pump truck of the present invention.
• the hydraulic cylinder provided by the present invention can also be used in other types of construction machinery.

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

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Cited By (5)

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• 2010
  • 2010-07-23 CN CN2010102351377A patent/CN102108990B/zh active Active
• 2011
  • 2011-06-21 AU AU2011282321A patent/AU2011282321B9/en active Active
  • 2011-06-21 CA CA2805789A patent/CA2805789C/en active Active
  • 2011-06-21 EP EP11809220.4A patent/EP2597319B1/en active Active
  • 2011-06-21 RU RU2013100913/06A patent/RU2564161C2/ru active
  • 2011-06-21 US US13/811,636 patent/US20130209296A1/en not_active Abandoned
  • 2011-06-21 WO PCT/CN2011/076025 patent/WO2012010032A1/zh active Application Filing
  • 2011-06-21 BR BR112013001759-7A patent/BR112013001759B1/pt active IP Right Grant

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