CN102155456B - Hydraulic oil cylinder, hydraulic buffer system, excavator and concrete pump truck - Google Patents

Abstract

The invention discloses a hydraulic oil cylinder. The additional section of the piston rod located in the rodless chamber is covered with a buffer sleeve capable of sliding axially along the additional section of the piston rod; In the oil cylinder cavity between the end positions of the end faces of the rodless cavity of the piston, there is provided a closed end surface of the rodless cavity that can block the buffer sleeve and can be fitted with the first end surface of the buffer sleeve to form a sealing surface; at least one throttling The oil passage, during the retraction movement of the piston rod, begins when the first end surface of the buffer sleeve is attached to the closed end surface of the rodless chamber and the sealing surface is formed, until the piston rod retracts to the end position of the retraction movement , the hydraulic oil on the side of the sealing surface close to the piston can flow to the oil passage hole of the rodless chamber through the throttling oil passage. The above-mentioned hydraulic oil cylinder has the advantages of simple processing of the buffer structure and good effect. The invention also provides a hydraulic buffer system, an excavator and a concrete pump truck using the hydraulic oil cylinder.

Description

A hydraulic cylinder, a hydraulic buffer system, an excavator and a concrete pump truck

This application is a branch of a Chinese patent application submitted to the China Patent Office on July 23, 2010, with the application number 201010235136.2, and the title of the invention is "a hydraulic cylinder and its related devices, and hydraulic buffer system, excavator and concrete pump truck". application, the entire contents of which are incorporated in this application by reference.

technical field

The invention relates to the field of hydraulic technology, in particular to a hydraulic oil cylinder. The present invention also provides a related device for the hydraulic cylinder, a hydraulic buffer system using the hydraulic cylinder, and an excavator and a concrete pump truck using the hydraulic cylinder.

Background technique

The hydraulic cylinder is a widely used part in construction machinery. During its working process, the piston needs to reciprocate continuously. When the piston rod extends to the limit position, the end face of the piston will have a great impact on the end cover, which may cause damage to the hydraulic cylinder. For this reason, it is necessary to install a buffer device at this position to avoid damage to the hydraulic cylinder due to the above-mentioned impact.

Existing buffer devices vary greatly depending on the application occasion and size of the hydraulic cylinder. Small oil cylinders can directly use compression springs as buffer devices. However, for hydraulic cylinders with large cylinder diameters and large strokes, if compression springs are used as buffer devices, it will be difficult to obtain springs with sufficient elasticity. It will be damaged by repeated compression. Therefore, for hydraulic cylinders with large cylinder diameters and large strokes, the hydraulic buffer mechanism shown in Figure 1 is usually used.

Please refer to Fig. 1, which shows that the buffer device includes a small buffer ring 06 installed on the intermediate ring groove provided by the additional section of the piston rod and a small buffer sleeve 04 sleeved on the additional section of the piston rod; corresponding to the small buffer sleeve 04 , In the cover mouth portion of the rodless chamber end cover 01 of the oil cylinder, a buffer inner hole 07 whose inner diameter matches the outer diameter of the small buffer sleeve 04 is set. When the piston rod is retracted, the small buffer sleeve 04 is first inserted into the buffer inner hole 07, so that the oil return circuit of the rodless cavity in the cylinder 02 is blocked, and at the same time, the small buffer sleeve 04 and The gap between the buffer inner holes 07 forms a throttling oil passage; in this way, the piston 05 can continue to move in the retracting direction, and at the same time, it is damped by the throttling oil passage, and its movement speed decreases. In addition, the closer the piston 05 is to the end position of the retraction of the piston rod 03, the longer the throttling oil passage between the small buffer sleeve 04 and the buffer inner hole 07, the greater the damping of the throttling oil passage, and the slower the movement of the piston 05. Until the end point of the retraction movement of the piston rod 03 is reached smoothly at last.

The above buffer mechanism is currently widely used in hydraulic cylinders with large cylinder diameters and large strokes to provide better buffer protection for hydraulic cylinders.

However, there are also obvious defects in the above-mentioned buffer mechanism. First of all, in the above-mentioned hydraulic cylinders with large bore and large stroke, the hydraulic cylinders often work under the working conditions of large load and high frequency. For example, the drive cylinder used in the excavator arm drive and other occasions. At this time, the large buffer sleeve 04 in the above-mentioned buffer mechanism needs to be repeatedly inserted into the buffer inner hole 07 at high speed, and the fit gap between the two is originally very small, and the piston rod 03 is very heavy. It is easy to tilt to one side; therefore, the hydraulic cylinder used in the above occasions is prone to failure of the buffer mechanism in which the buffer sleeve 04 cannot be inserted into the buffer inner hole 07, resulting in the failure of the entire hydraulic cylinder.

Another key problem of the above-mentioned buffer mechanism is that the outer diameter of the large buffer sleeve 04 must precisely match the inner diameter of the buffer inner hole 07, otherwise the buffer effect cannot be achieved; this results in extremely high manufacturing precision requirements for the buffer mechanism , the manufacturing level of general manufacturers is difficult to achieve. Due to the above-mentioned high requirements for manufacturing precision, hydraulic cylinders with large strokes and large bores have become bottlenecks in the production of excavators and other construction machinery, severely limiting the production capacity of various downstream manufacturers.

Contents of the invention

The invention provides a hydraulic oil cylinder. The buffer mechanism of the hydraulic oil cylinder can reliably realize the buffer effect under the working conditions of large load and high frequency, and has a longer service life. In addition, the hydraulic oil cylinder requires low manufacturing precision and is convenient for organizing production. The hydraulic cylinder is especially suitable for the manufacture of large bore and long stroke hydraulic cylinders.

The present invention also provides a device related to the above-mentioned hydraulic oil cylinder, including the piston rod used therein, the end cover of the rod chamber and the buffer sleeve.

The present invention also provides a hydraulic buffer system using the above-mentioned hydraulic oil cylinder.

The present invention also provides an excavator using the above-mentioned hydraulic oil cylinder.

The present invention also provides a concrete pump truck using the above-mentioned hydraulic oil cylinder.

The invention provides a hydraulic oil cylinder, which is equipped with a buffer sleeve capable of sliding axially along the additional section of the piston rod on the additional section of the piston rod located in the rodless cavity; the end surface of the buffer sleeve facing the bottom of the cylinder is called It is the first end surface of the buffer sleeve; in the oil cylinder cavity between the rodless cavity oil hole and the end position of the piston rodless cavity end surface of the piston rod retraction movement, there is a buffer sleeve that can block the buffer sleeve and can be connected with the buffer sleeve. One end surface fits the closed end surface of the rodless cavity forming a sealing surface; at least one throttle oil passage is also provided, and during the retraction process of the piston rod, the first end surface of the buffer sleeve is attached to the closed end surface of the rodless cavity, When the sealing surface is formed, and when the piston rod retracts to the terminal position of the retraction movement, the hydraulic oil on the side of the sealing surface close to the piston can flow to the oil passage hole of the rodless chamber through the throttling oil passage.

Preferably, the throttling oil passage is arranged between the piston rod and the buffer sleeve along the axial line.

Preferably, the end of the throttling oil passage close to the piston is called the first end, and the end close to the oil passage hole of the rodless chamber is called the second end, and the cross-sectional area of the throttling oil passage is from the first end to the second end. Both ends gradually increase.

Preferably, when the piston rod is retracted to the end position, there is a certain distance between the buffer sleeve and the end point where it slides toward the piston.

Preferably, when the first end surface of the buffer sleeve is in contact with the sealed end surface of the rodless cavity to form a sealing surface, the axial action area of the hydraulic oil on the side of the sealing surface close to the piston on the buffer sleeve is larger than that close to the rodless cavity. The axial action area of the hydraulic oil on one side of the oil hole on the buffer sleeve.

Preferably, the elastic element with compression elasticity installed in the rodless cavity pushes the buffer sleeve against the shoulder at the end of the additional section of the piston rod.

Preferably, the shoulder at the end of the additional section of the piston rod adopts a snap-in structure including two half-round keys.

Preferably, at the terminal position of the retraction movement of the piston rod, there is provided a piston blocking shoulder that allows the buffer sleeve to pass through but can block the piston at this position.

Preferably, the main body of the throttling oil passage is a throttling groove axially arranged on the surface of the additional section of the piston rod.

Preferably, the cross-sectional area of the throttling groove gradually increases from the first end close to the piston to the second end close to the oil passage hole of the rodless chamber; when the width thereof remains constant, the increase in the cross-sectional area is specifically Manifested by an increase in its depth.

Preferably, the main body of the throttling oil passage is a throttling groove axially arranged on the surface of the additional section of the piston rod, and the cross-sectional area of the throttling groove ranges from the first end near the piston to the oil passage near the rodless chamber. The second end gradually increases; the snap key is provided with an annular groove on the end face of the piston, and the outlet of the throttling groove communicates with the annular groove.

Preferably, one or several ring grooves are set on the additional section of the piston rod as balance grooves; or, one or more ring grooves are set on the inner diameter surface of the buffer sleeve as balance grooves, and the cross section of the ring grooves can be V-shaped, U-shaped, or U-shaped. type or square or other cross-sectional forms.

Preferably, the throttling oil passage includes two sections, the front section near the first end is a throttling groove axially arranged on the surface of the piston rod, and the rear section near the second end is a dark oil passage extending axially in the piston rod ; The depth of the throttling groove is gradually deepened from the first end to the second end.

Preferably, the throttling oil channel includes a dark oil channel extending axially in the piston rod, and several oil saving holes connecting the surface of the piston rod and the dark oil channel, and the above oil saving holes are axially distributed along the surface of the piston rod, And the oil saving hole closer to the second end of the throttling oil passage has a larger aperture; the second end of the throttling oil passage is the outlet of the dark oil passage, and the oil saving hole is the first end of the throttling oil passage.

Preferably, the throttling oil channel is an axially arranged chamfered surface on the surface of the piston rod, and the chamfered plane is inclined from the end of the piston toward the end of the additional section of the piston rod.

Preferably, the sealed end surface of the rodless chamber is arranged on the end cover of the rodless chamber.

The present invention also provides a related device of a hydraulic oil cylinder, specifically a piston rod. The piston rod is provided with at least one axially extending throttling oil passage in the additional section located in the rodless chamber, and one end of the throttling oil passage is close to the installation The position of the end face of the piston rodless cavity behind the piston is called the first end; the other end is at least at the position of the first end face of the buffer sleeve when the buffer sleeve is not blocked, or is closer to the end of the additional section, called the second end. Two ends; the end of the additional section is provided with a shoulder stop.

Preferably, the throttling oil channel is a throttling groove opened on the surface of the piston rod, the throttling groove is arranged in a straight line along the axial direction, and its cross-sectional area gradually increases from the first end to the second end.

Preferably, several annular grooves are provided on the outer diameter surface of the additional section of the piston rod as balance oil grooves.

The present invention also provides another related device of the hydraulic cylinder, specifically a buffer sleeve whose outer diameter is smaller than the inner diameter of the cylinder barrel of the working hydraulic cylinder, and whose inner diameter enables it to be sleeved on the buffer position of the piston rod and slide freely in the axial direction; When it is installed, the first end surface on the side away from the piston can be fitted with the closed end surface of the rodless cavity in the cylinder cavity, between the oil passage hole of the rodless cavity and the end point of the retraction movement of the end surface of the rodless cavity of the piston, forming a sealing surface .

Preferably, the second end face of the buffer sleeve opposite to the closed end face of the buffer sleeve is provided with a central boss cooperating with the pressure spring.

The invention provides a related device of a hydraulic oil cylinder, specifically an additional section of a piston rod, the front part of which is provided with a head with an external thread that cooperates with a threaded hole on the tail end of the piston rod body; a key structure is provided at the end; The body is provided with a throttling oil passage, one end of which is close to the end face of the rodless cavity of the piston after the piston is installed, and the other end is at least at the position of the sealed end face of the buffer sleeve when the buffer sleeve is not blocked, or at the The location closer to the end of the additional section of the piston rod.

Preferably, the throttling oil channel is a throttling groove opened on the surface of the additional section of the piston rod, the throttling groove is arranged in the axial direction, and its cross-sectional area gradually increases from the first end to the second end.

The present invention provides a hydraulic buffer system, which uses the hydraulic oil cylinder described in any one of the above technical solutions.

The present invention also provides an excavator, which at least uses the hydraulic cylinder described in any one of the above technical solutions.

The present invention also provides a concrete pump truck, which uses at least one hydraulic cylinder described in any one of the above technical solutions.

In the hydraulic oil cylinder provided by the present invention, the first end surface of the buffer sleeve can cooperate with the closed end surface of the rodless chamber arranged in the rodless chamber when the piston rod retracts and moves to a position requiring buffering, to form a sealing surface for blocking the oil circuit, The sealing surface divides the rodless cavity into two cavities, the cavity located on the side of the sealing surface close to the piston is called the buffer oil cavity; the other cavity is located on the side of the sealing surface close to the oil hole of the rodless cavity. The hydraulic oil in the buffer oil chamber has a relatively large oil pressure under the push of the piston, which can firmly press the first end surface of the buffer sleeve against the closed end surface of the rodless chamber, so that the two are bonded together to form a The sealing effect of the sealing surface is more reliable; the oil cylinder is also provided with a throttling oil passage, which is formed on the sealing surface, and can be used as a buffer during the period until the piston reaches the end position of the retraction movement. The hydraulic oil in the oil chamber provides an oil passage to one side of the oil hole. Since the sealing surface of the cut-off oil passage is formed, the hydraulic oil can only flow to the oil hole through the throttling oil passage, and the oil passage of the throttling oil passage is very narrow, and the hydraulic oil passage capacity is limited, so that the piston movement must be greatly affected. The resistance acts as a buffer.

In a preferred embodiment of the present invention, the above-mentioned throttling oil passage is arranged between the additional section of the piston rod and the buffer sleeve along the axial line, and its first end is in the rod chamber close to the end surface of the rod chamber of the piston. The outlet is located at any position between the first end surface of the buffer sleeve and the top end of the rod cavity, and this position is still in the cylinder when the piston rod extends to the end; through the above-mentioned setting, after the sealing surface is formed, the A throttling oil passage is formed to avoid piston sticking.

In a further preferred solution, the main body of the throttling oil passage is a throttling groove axially arranged on the surface of the piston rod, and the cross-sectional area of the throttling groove gradually increases from the first end to the outlet. In this way, as the piston moves toward the end position of the retraction movement, the relative position of the buffer sleeve on the piston rod gradually approaches the position of the first end of the throttling oil passage, from the buffer oil chamber side of the sealing surface to the oil passage hole The discharge capacity of one side gradually decreases, the resistance of the piston to continue to retract gradually increases, and the movement speed of the piston gradually decreases, obtaining a good buffering effect. Due to the adoption of the throttling groove arranged in a straight line in the axial direction, under the condition that the width of the throttling groove remains unchanged, as long as the depth change of the throttling groove is well controlled, the throttling effect can be well controlled, and the purpose of smooth buffering process can be achieved.

In a further preferred embodiment of the present invention, when the throttling groove is provided, several annular grooves are set on the outer diameter surface of the additional section of the piston rod or the inner diameter surface of the buffer sleeve as balance oil grooves, and the balance oil grooves can be connected with the throttle The grooves cooperate to make the hydraulic oil evenly 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 will not be deflected when they are fitted together, ensuring that the sealing surface is firm.

In another preferred embodiment of the present invention, the following conditions are required to be established: when the first end surface of the buffer sleeve is in contact with the closed end surface of the rodless chamber to form a sealing surface, the hydraulic oil on the side of the sealing surface close to the piston will The axial action area of the buffer sleeve is larger than the axial action area of the hydraulic oil on the side of the rodless cavity through the oil hole. The above requirements are easily ensured by proper design of the two end faces of the buffer sleeve. If the above conditions are not established, at the moment when the sealing surface is formed, the oil pressure on both sides of the sealing surface is basically the same, and the first end surface of the buffer sleeve is pressed against the closed end surface of the rodless cavity at a certain speed, and it may not be compacted at this moment. Affects the smoothness of buffering at this point in time. After ensuring that the above conditions are established, the oil pressure on the side of the sealing surface close to the piston is multiplied by the axial action area of the buffer sleeve at this end to obtain the total pressure V1, and the oil pressure on the side of the sealing surface close to the oil outlet of the rodless cavity is multiplied by the buffer The area sleeved 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 when the sealing surface is formed, the total pressure on the side with a larger area is greater, that is, V1>V2, so that the buffer The sleeve is pressed against the airtight end surface of the rodless cavity, which ensures the smoothness of the buffering process.

Other preferred implementations of the present invention also provide other forms of throttling oil passages, and these throttling oil passages can all achieve good discharge effects.

The present invention also provides parts such as the piston rod, the end cover of the rod chamber and the large buffer sleeve used for the above-mentioned hydraulic oil cylinder, all of which are specially designed to realize the above-mentioned buffer mechanism.

The present invention also provides a buffer system using the above-mentioned hydraulic oil cylinder at the same time, and the hydraulic buffer system using the hydraulic oil cylinder can obtain a good and stable buffer effect.

The present invention also provides an excavator and a concrete pump truck using the above-mentioned hydraulic oil cylinder at the same time. By using the above-mentioned hydraulic oil cylinder, the excavator and the concrete pump truck can obtain a longer trouble-free service time.

Description of drawings

Fig. 1 is the hydraulic cylinder of the buffer mechanism that adopts the buffer sleeve inserted into the buffer inner hole form in the background technology;

Fig. 2 is a mechanical structure diagram of the hydraulic cylinder provided by the first embodiment of the present invention, in which the piston has not yet retracted to the buffer position of the rodless chamber;

Fig. 3 is a part diagram of the piston rod of the first embodiment of the present invention;

Fig. 4 is that this figure is the A-A direction view of piston rod 3;

Fig. 5 is the state when the hydraulic cylinder of the first embodiment of the present invention is at the position where the sealing surface starts to form;

Fig. 6 is the state of the hydraulic cylinder in the first embodiment of the present invention when the piston moves to the end position;

Fig. 7 is a part diagram of the piston rod in which the throttling oil passage adopts the form of an oblique section;

Fig. 8 is a key structure diagram of the end of the additional section of the piston.

Detailed ways

The first embodiment of the present invention provides a hydraulic cylinder, the hydraulic cylinder is provided with a buffer device on one side of the rodless cavity.

Please refer to FIG. 2 , which is a mechanical structure diagram of the hydraulic cylinder provided by the first embodiment of the present invention. In this figure, the piston has not been retracted to the rodless chamber buffer position.

As shown in FIG. 2 , the hydraulic cylinder includes a rodless chamber end cover 1 , a cylinder barrel 2 , a piston rod 3 , a buffer sleeve 4 , a spring 5 , and a piston 6 .

The cylinder 2 provides a sealed hydraulic oil space for the hydraulic cylinder, and the inner cavity of the cylinder 2 is divided into a rod cavity 2-1 and a rodless cavity 2 by a piston 6 that can move axially along the inner cavity. -2, the cavity where the main body of the piston rod 3 is located is the rod cavity 2-1. The outer diameter surface of the piston 6 cooperates with the inner diameter surface of the cylinder barrel 2, and multiple sealing rings are arranged on the outer diameter surface, so that the hydraulic oil in the rod chamber 2-1 and the rodless chamber 2-2 is completely isolated from each other. In order to install the buffer device of the rodless chamber, the piston rod 3 is also provided with an additional section 3a of the piston rod located on one side of the chamber. The external thread of the outer thread cooperates with the threaded hole on the end face of the main body tail end of the piston rod 3, and it is connected with the main body of the piston rod 3 as a whole. Of course, the additional section 3 a of the piston rod can be integrally made with the main body of the piston rod 3 .

The end of the rodless chamber end cover 1 on the side of the rodless chamber 2-2 of the cylinder 2 seals the cylinder 2, and the rodless chamber end cover 1 provides a rodless chamber oil passage Hole 1-1, the rodless chamber through the oil 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 rodless chamber 2-2. The channel for the hydraulic oil to enter and exit the rod chamber 2-1 is provided by the rod chamber oil passage provided on the end cover of the cylinder barrel 2. This embodiment only introduces the buffer device on the side of the rodless cavity, and does not involve the situation on the side of the rod cavity 2-1.

The buffer mechanism of the hydraulic oil cylinder includes a buffer sleeve 4, a spring 5, and a structure arranged on the piston 6, the piston rod 3 and the end cover 1 of the rodless cavity to form the buffer mechanism.

The buffer sleeve 4 is sleeved on the additional section 3a of the piston rod 3 located in the rodless chamber 2-2. The additional section 3a of the piston rod is a section added at the end of the body of the piston rod 3 for the purpose of arranging the buffer structure, and this section is located in the rodless chamber of the piston. At the end of the additional section 3a of the piston rod, a shoulder stop 3-2 is arranged so that the buffer sleeve 4 will not slip off from the additional section 3a of the piston rod. . The inner diameter of the buffer sleeve 4 enables it to slide axially on the piston rod 3 while the gap between the two is small; the outer diameter of the buffer sleeve 4 is obviously smaller than the inner diameter of the cylinder 2 . The end face of the buffer sleeve 4 facing the bottom end of the cylinder, that is, the side of the rodless chamber end cover 1, is a plane with chamfered outer edges, which is called the first end face 4-1 of the buffer sleeve. The other end of the buffer sleeve 4 is called the second end surface 4-2 of the buffer sleeve, and a boss 4-3 for fixing the spring 5 is also provided.

The spring 5 is a compression spring with compression tension, the spring 5 is sleeved on the additional section 3a of the piston rod, and its bottom end is against the end face of the piston 6 on the side of the rodless cavity 2-2, and the piston 6 is on the end face of the rodless chamber 2-2. A spring boss is arranged on the end face to fix the spring. The end of the spring 5 bears against the boss 4 - 3 of the buffer sleeve 4 . The spring 5 relies on the end face of the piston 6 to withstand the buffer sleeve 4 with its elastic force, so that when the piston rod 3 is not retracted to the buffer position, the first end surface 4-1 of the buffer sleeve pushes against the buffer sleeve 4. Hold the shoulder 3-2 of the additional section 3a of the piston rod. The elastic force of the spring 6 is enough to make the buffer sleeve 4 withstand the shoulder 3-2 when it is not blocked, that is, the function of the spring 6 is reset.

The end cover 1 of the rodless cavity is sequentially provided with a rodless cavity oil passage 1-1 and a closed end surface 1-2 of the rodless cavity from the top of the cover to the cover opening. The sealed end surface 1-2 of the rodless chamber is a complete annular stepped surface provided in the inner cavity of the rodless chamber end cover 1, and the stepped surface faces the direction of the piston 6. The closed end surface 1-2 can cooperate with the first end surface 4-1 of the buffer sleeve to form a closed surface for blocking the hydraulic oil in the rodless cavity 2-2 when the piston rod 3 retreats to the position where buffering is required. The cover part of the rodless cavity end cover 1 is close to the inner wall of the cylinder, and the diameter of the buffer sleeve 4 is smaller than the inner diameter of the cover part so that it can pass through this section when it is retracted, and the piston 6 will be covered by the cover end surface. Therefore, the cover opening of the rodless cavity end cover 1 also forms a piston blocking shoulder 1-3 capable of positioning the end point of the movement of the piston 6.

The additional section 3 of the piston rod is provided with many structures related to the buffer mechanism. In addition to the shoulder 3-2, it is also provided with a throttling groove, a balance oil groove, etc., which will be described in detail below. Please refer to Fig. 3 at the same time, which is a part diagram of the piston rod 3; please refer to Fig. 4 at the same time, which is an A-A view of the additional section 3a of the piston rod.

At least one throttling oil passage is arranged on the piston rod 3 , the main body of which is a throttling groove 3 - 1 extending axially on the outer diameter surface of the piston rod 3 . The throttling groove 3-1 is arranged on the piston rod, its starting point (or called the first end) is at the position close to the end face of the rodless chamber of the piston, and its end point (or called the second end) reaches the additional section of the piston rod The side wall of the key groove of the key is installed on the shoulder portion 3-2 at the end of 3a. The position of the first end close to the end face of the rodless cavity of the piston is relative to its end point; in fact, the first end of the throttling groove 3-1 needs to cooperate with the end position of the retraction movement of the piston rod 3 , there is a suitable hydraulic buffer capacity before the piston rod 3 is retracted to the end position. In this embodiment, before the piston rod 3 retracts to the terminal position, the first end has been completely covered by the buffer sleeve 4 .

The tail end of the piston rod is provided with a shoulder stop 3-2 for the positioning of the buffer sleeve, and the shoulder stop includes a key 3-2-1, a key cap 3-2-2 and a retaining ring 3-2-3; The key 3-2-1 is two semicircular keys, and the semicircular key is a ring structure; the cross section of the key 3-2-1 is L-shaped, and one side of the L-shaped side is clamped on the piston rod. The corresponding key groove at the end of the segment 3a, and the other side faces the direction of the piston. An annular groove 3-2-4 is provided on the side facing the piston, and the position of the annular groove 3-2-4 is such that it can engage with the second end of the throttle groove 3-1. The key cap 3-2-2 is ring-shaped, set in the key groove position where the key 3-2-1 is installed, and plays the role of fixing the key 3-2-1; the retaining ring 3-2-3 is embedded in the groove of the retaining ring at the end, and is used for positioning the keycap 3-2-2. The shoulder stop structure can be used as a general bayonet structure for other occasions. As corresponding to the second end of the throttling groove 3-1, an annular groove 3-2-4 is provided on the key 3-2-1. As can be seen from FIG. 4, the annular groove 3- The position of 2-4 is just aligned with the outlet of the throttle groove 3-1. Since the key 3-2-1 is divided into upper and lower parts, the hydraulic oil flowing into the annular groove 3-2-4 from the throttling groove 3-1 can flow out through the gap between the upper and lower parts of the key 3-2-1 Therefore, the annular groove 3-2-4 provides an outlet channel for the hydraulic oil flowing out of the outlet of the throttle groove 3-1, especially at the first end surface 4-1 of the buffer sleeve and the rodless The outlet of the hydraulic oil is provided at the moment when the sealed end faces 1-2 of the cavity are just fitted together, so as to avoid the sudden increase of resistance hydraulic damping and ensure stable operation.

Several ring grooves are evenly arranged on the peripheral surface of the additional section 3 of the piston rod, and these ring grooves are called balance oil grooves 3-3. The cross-sections of these balancing oil grooves 3-3 can be U-shaped, V-shaped or square-bottomed, and other forms, determined as required, and its depth can also be determined through tests as required. The function of these balance oil grooves 3-3 is to realize the oil pressure balance in the circumferential direction when the throttle groove 3-1 discharges, so as to prevent the buffer sleeve 4 from tilting under the action of unbalanced oil pressure, which will cause the sealing surface to be damaged during buffering. It is not tightly sealed.

The following describes the working process of the buffer mechanism of the hydraulic cylinder of this embodiment. Aforesaid Fig. 2 is the situation when the piston 6 has not yet reached the buffer position; please also refer to Fig. 5, which shows the situation at the beginning of the buffer process; please also refer to Fig. 6, which shows the situation at the end of the buffer process.

In the position shown in Fig. 2, the piston rod 3 has just started to retract and has not yet reached the position where buffering is required. At this time, under the action of the elastic force of the spring 5, the first end surface 4-1 of the buffer sleeve 4 bears against the shoulder 3-2 at the end of the additional section 3a of the piston rod. Before the piston 6 has moved to the buffer position, and after the piston rod 3 retracts to separate the first end surface 4-1 of the buffer sleeve from the closed end surface 1-2 of the rodless chamber, the buffer sleeve 4 will be pushed against the shoulder 3-2 position, therefore, the spring 5 plays a reset role. With the retraction and movement of the piston rod 3, the hydraulic oil in the rodless chamber 2-1 is pushed by the piston, flows toward the rodless chamber oil passage hole 1-1, and flows from the rodless chamber oil passage hole 1-1. 1 flow out. The buffer sleeve 4 moves with the piston 6 and the piston rod 3. After moving for a certain distance, the buffer sleeve 4 passes through the cover opening of the rodless cavity end cover 1. Since the outer diameter of the buffer sleeve 4 is smaller than the cover opening, The buffer sleeve 4 can continue to move with the piston rod 3 without being blocked.

After the buffer sleeve 4 passes through the mouth of the cover, its first end surface 4-1 will be attached to the closed end surface 1-2 of the rodless chamber on the end cover 1 of the rodless chamber soon. That is, it moves to the position shown in Fig. 5, the first end surface 4-1 of the buffer sleeve abuts against the closed end surface 1-2 of the rodless cavity on the end cover 1 of the rodless cavity, and the two end surfaces fit together to form a complete On the sealing surface, the passage of the hydraulic oil pushed by the piston 6 in the rodless chamber 2-1 to the oil outlet of the rodless chamber is blocked, and the buffer sleeve 4 stops following the piston rod 3 because it is blocked by the airtight end surface 1-2 forward motion.

At the moment when the sealing surface is formed, the oil pressure on both sides of the sealing surface is basically the same, and the first end surface 4-1 of the buffer sleeve presses against the closed end surface 1-2 of the rodless cavity at a certain speed, which may not be compacted at this moment , which affects the smoothness of the buffer at this time point. For this reason, in the design, the establishment of the following conditions has been ensured: when the first end surface 4-1 of the buffer sleeve is in contact with the closed end surface 1-2 of the rod cavity to form a sealing surface, the sealing surface is close to the side of the piston. The axial action area of the hydraulic oil on the buffer sleeve is larger than the axial action area of the hydraulic oil on the side of the rodless chamber oil passage hole on the buffer sleeve. In this embodiment, the areas of the two end surfaces of the buffer sleeve 4 are the same, but after the sealing surface is formed, the above condition can be established because the first end surface 4-1 is partially covered. After the above conditions are established, the oil pressure on the side of the sealing surface close to the piston is multiplied by the axial action area of the buffer sleeve at this end to obtain the total pressure V1, and the oil pressure on the side of the sealing surface close to the oil outlet hole of the rod cavity is multiplied by the buffer sleeve The area 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 when the sealing surface is formed, the total pressure on the side with a larger area is greater, that is, V1>V2, so that the buffer sleeve It is compacted on the closed end surface 1-2 of the rodless cavity, which ensures the smoothness of the sealing surface establishment process.

After the sealing surface is established, the buffer sleeve 4 and the end cap 1 of the rodless cavity form a one-way valve, and the oil passage is blocked. At this time, the hydraulic oil in the rodless cavity is divided into two cavities by the sealing surface, among which the side close to the piston 3 is called the buffer oil cavity T, and the hydraulic oil in the buffer oil cavity T is pushed by the piston 6, And its main passage to the oil passage of the rodless chamber is restricted due to the formation of the sealing surface, so that the pressure of the buffer oil chamber is further increased, and the increased oil pressure is enough to compress the buffer sleeve 4 on the place. On the airtight end surface 1-2 of the rodless cavity, the sealing surface is more reliable.

Hydraulic oil can only flow to the side of the rodless chamber oil passage hole 1-1 on the above-mentioned closed surface through the throttling groove 3-1 at this time. In the initial stage of sealing surface formation, since the depth of the throttle groove 3-1 is relatively deep on the outlet side, that is, the flow capacity of the throttle groove 3-1 is relatively high, so that the hydraulic pressure flowing out through the throttle groove 3-1 Relatively more oil. As the piston rod 3 continues to move, the sealing surface moves backward relative to the additional section 3 of the piston rod, and the depth of the throttle groove 3-1 connecting the two sides of the sealing surface gradually becomes shallower, resulting in the throttle groove 3-1 The flow capacity of the flow is gradually reduced. In the above process, while the hydraulic oil passes through the throttling groove 3-1, it passes through the balance oil groove 3-3 and fills up on the shaft section where the buffer sleeve is located, so that the oil pressure received by the buffer sleeve is at each position in the circumferential direction. The balance ensures that the buffer sleeve 4 will not deflect and ensures the sealing effect of the sealing surface.

After reaching the position shown in Figure 6, the piston 6 is blocked by the piston blocking shoulder 1-3 formed by the end face of the rodless chamber end cover of the rodless chamber end cover 1 and cannot continue to move forward, and the piston rod 3 reaches its retracted terminal position ; The first end of the throttling groove 3-1 has entered the buffer sleeve 4 at this time, the throttling oil passage is basically closed, and the buffering process ends. It should be noted that after the piston 6 moves to the end position, there is still a distance L between the second end face 4-2 of the buffer sleeve 4 and the end face of the rodless cavity of the piston 6, which ensures that the buffer sleeve 4 does not Will block the normal movement of piston 6.

In fact, since there is a gap between the buffer sleeve 4 and the piston rod 3, a small amount of hydraulic oil can also enter the throttling groove 3-1 through the gap between the two and realize the discharge. After the first end of the groove 3-1 is completely covered by the buffer sleeve 4, the piston 6 will not be stuck due to the excessive hydraulic oil in the buffer oil chamber; of course, the first end of the throttle groove 3-1 The end can also be exposed outside the buffer sleeve 4 when the piston rod 3 reaches its retracted end position. Where the position of the first end of the throttling groove 3-1 is specifically designed and the positional relationship with the buffer sleeve 4 can be designed according to the requirements of buffering and damping.

During the above buffering process, the damping effect of the hydraulic oil increases from the formation of the sealing surface; especially through the depth change of the throttle groove 3-1, the throttling capacity is gradually increased, and the hydraulic damping is gradually increased, so that the piston 6 reaches the end point. The speed before the position gradually decreases, and in the last short distance, it is even possible to use only the gap between the buffer sleeve 4 and the additional section 3a of the piston rod to form a throttling oil circuit, so that the hydraulic damping gradually increases during the entire buffering process, avoiding Impact on rodless chamber cover 1 and cylinder barrel 2.

In the above buffer mechanism, under the condition that the width is kept constant, the variation curve of the throttling capacity can be controlled by controlling the depth variation of the throttling groove 3-1, so as to ensure that the piston 6 can obtain a very smooth buffering process.

In fact, the balance oil groove may not be arranged on the piston rod 3 , but on the inner diameter surface of the buffer sleeve 4 , and its effect is the same as that on the piston rod 3 . In addition, the balance oil groove 3-3 may not actually be in the form of an annular groove, for example, a threaded groove may be used, but the annular groove used in this embodiment is preferred because it is more convenient to process and has a better balancing effect .

In the above embodiments, the passages connecting the cavities on both sides of the sealing surface after the sealing surface is formed are collectively referred to as throttling oil passages. In the above embodiments, the main body of the throttling oil passage is the throttle groove. However, at different times , The composition of the throttling oil passage is also different. At the moment when the sealing surface is just formed, the annular groove 3-2-4 corresponding to the throttling groove on the key 3-2-1 assumes the role of the outlet of the throttling passage, which plays a role in the smoothness of the buffering process. important role. When the buffer sleeve 4 slides to the end of the buffer position, if the throttling groove is completely covered by the buffer sleeve, the gap between the buffer sleeve 4 and the piston rod 3 also forms a part of the throttling oil passage.

In the above embodiments, the outlet of the throttling oil passage is arranged on the side wall of the groove of the key. In fact, the throttling oil passage can be arranged at a more terminal position, for example, on the end face of the additional section of the piston rod.

In the above embodiment, the sealed end surface of the rodless cavity and the first end surface of the buffer sleeve are bonded to form a face-to-face sealing surface. In fact, the sealed end surface of the rodless cavity and the first end surface of the buffer sleeve can also be Corresponding design is carried out so that the airtight surface formed after the two are bonded is any one of the surface sealing forms such as flat sealing, conical sealing or curved sealing, or line sealing.

Although in the above embodiments, the main body of the throttling oil passage is in the form of a throttling groove provided on the surface of the additional section 3a of the piston rod, in fact, the throttling oil passage can choose other structural forms.

For example, the throttling oil passage may include two sections, the front section near the first end is a throttling groove axially arranged on the surface of the additional section of the piston rod, and the rear section near the outlet is the dark oil axially extending in the additional section of the piston rod Dao, this can also play a role in throttling. One section of the throttling groove can also be set in a form that gradually deepens from the first end to the outlet, so as to achieve a smooth buffering effect.

In another way, the throttling oil passage includes a dark oil passage extending axially in the buffer bushing, and several oil saving holes connecting the surface of the additional section of the piston rod and the dark oil passage, and the above oil saving holes are arranged along the piston rod. The surface of the rod is axially distributed, and the closer to the oil-saving hole at the end position, the larger the hole diameter; in this way, as the buffer sleeve slides on the piston rod, the closer the piston rod 3 is to the retracted end position, the smaller its discharge capacity , the greater the hydraulic damping effect, the piston speed will gradually decrease, and a more stable buffering process will be obtained.

The throttling oil passage can also be a chamfered surface 3-5 axially arranged on the surface of the additional section 3a of the piston rod as shown in FIG. 7 . The beveled surface 3-5 is inclined from the position close to the piston to the shoulder portion 3-2, and one or more beveled surfaces can be provided. In this way, after the first end surface 4-1 of the buffer sleeve and the closed end surface 1-2 of the rodless chamber end cover 1 form a closed surface, the hydraulic oil can flow out through the chamfered surface 3-5 to form a throttling oil passage. Using the beveled surface 3-5 as the throttling oil passage can also make the closer the piston rod 3 is to the end point of retraction, the smaller the discharge capacity and the greater the hydraulic damping effect, so that the speed of the piston 6 is gradually reduced, and a relatively stable buffering process.

The embodiment of the hydraulic buffer system of the present invention can be obtained by using the hydraulic oil cylinder provided by the present invention in a hydraulic buffer system to replace the existing oil cylinder.

The embodiment of the excavator of the present invention can be obtained by using the hydraulic oil cylinder provided by the present invention in an excavator.

The embodiment of the concrete pump truck of the present invention can be obtained by using the hydraulic oil cylinder provided by the invention for the concrete pump truck. The hydraulic oil cylinder provided by the invention can also be used in other types of engineering machinery.

Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be based on the scope defined by the claims of the present invention.

Claims (19)

1. A hydraulic cylinder, characterized in that, The additional section of the piston rod located in the rodless chamber is covered with a buffer sleeve that can slide axially along the additional section of the piston rod; the end face of the buffer sleeve facing the bottom of the cylinder is called the first end face of the buffer sleeve; In the oil cylinder cavity between the rodless cavity oil passage hole and the end position of the piston rodless cavity end surface of the piston rod retracting movement, there is a sealing surface that can block the buffer sleeve and fit with the first end surface of the buffer sleeve The closed end face of the rodless chamber; At least one throttling oil channel is also provided. During the retraction movement of the piston rod, the first end surface of the buffer sleeve is attached to the closed end surface of the rodless cavity, the sealing surface is formed, and the piston rod retracts to the closed end surface of the rodless cavity. When the end position of the retraction movement is reached, the hydraulic oil on the side of the sealing surface close to the piston can flow to the oil passage hole of the rodless cavity through the throttling oil passage; The shoulder at the end of the additional section of the piston rod adopts a key comprising two semi-circular structures; The cross-section of the key is L-shaped, one side of the L-shaped side is fitted in the key groove at the end of the additional section of the piston rod, and the other side faces the direction of the piston, and the L-shaped opening of the key is facing away from the Buffer sleeve direction; It also includes a key cap and a retaining ring; the key cap is ring-shaped, and is set in the position of the key groove where the key is installed to fix the key; the retaining ring is embedded in the retaining ring of the shoulder stop Position the card keycap in the slot. 2. The hydraulic oil cylinder according to claim 1, characterized in that, the end of the throttling oil channel close to the piston is called the first end, and the end close to the oil passage hole of the rodless chamber is called the second end; An annular groove is arranged on the side of the key facing the piston, and the position of the annular groove makes it engage with the second end of the throttling oil passage. 3. The hydraulic oil cylinder according to claim 1, characterized in that, the throttling oil passage is arranged between the piston rod and the buffer sleeve in a straight line along the axial direction. 4. The hydraulic cylinder according to claim 1, characterized in that, the end of the throttling oil channel close to the piston is called the first end, and the end close to the oil passage hole of the rodless chamber is called the second end, and the throttling oil passage The cross-sectional area of the track gradually increases from the first end to the second end. 5. The hydraulic cylinder according to claim 1, wherein when the piston rod is retracted to the end position, there is a certain distance between the buffer sleeve and the end point where it slides toward the piston. 6. The hydraulic cylinder according to claim 1, characterized in that, when the first end surface of the buffer sleeve is in contact with the closed end surface of the rodless cavity to form a sealing surface, the hydraulic oil on the side of the sealing surface close to the piston will The axial action area of the buffer sleeve is larger than the axial action area of the hydraulic oil on the side of the rodless chamber near the oil passage hole on the buffer sleeve. 7. The hydraulic oil cylinder according to claim 1, characterized in that, the elastic element with pressure elasticity installed in the rodless chamber pushes the buffer sleeve against the shoulder at the end of the additional section of the piston rod. 8 . The hydraulic cylinder according to claim 1 , wherein at the end position of the retraction movement of the piston rod, there is provided a piston blocking shoulder that allows the buffer sleeve to pass through but can block the piston at this position. 9. The hydraulic cylinder according to any one of claims 1 to 8, characterized in that, the main body of the throttling oil passage is a throttling groove axially provided on the surface of the additional section of the piston rod. 10. The hydraulic oil cylinder according to claim 9, wherein the cross-sectional area of the throttle groove gradually increases from the first end close to the piston to the second end close to the rodless chamber oil passage hole; Under the condition of constant, the increase of the cross-sectional area is embodied as the increase of its depth. 11. The hydraulic oil cylinder according to any one of claims 1 to 8, characterized in that, the main body of the throttling oil passage is a throttling groove arranged axially on the surface of the additional section of the piston rod, and the transverse direction of the throttling groove The cross-sectional area gradually increases from the first end close to the piston to the second end close to the oil passage hole of the rodless chamber; an annular groove is provided on the end surface of the key against the piston, and the outlet of the throttling groove communicates with the annular groove. 12. The hydraulic cylinder according to any one of claims 1 to 8, characterized in that one or several ring grooves are set on the additional section of the piston rod as balance grooves; or one or more ring grooves are set on the inner diameter surface of the buffer sleeve A ring groove is used as a balance groove, and the cross section of the ring groove is V-shaped, U-shaped or square. 13. The hydraulic oil cylinder according to claim 2, wherein the throttling oil passage includes two sections, the front section near the first end is a throttling groove axially arranged on the surface of the piston rod, and the rear section near the second end The section is a dark oil passage axially extending in the piston rod; the depth of the throttling groove is gradually deepened from the first end to the second end. 14. The hydraulic oil cylinder according to claim 2, characterized in that, the throttling oil passage includes a dark oil passage extending axially in the piston rod, and several oil throttling holes connecting the surface of the piston rod and the dark oil passage , the above-mentioned oil-saving holes are axially distributed along the surface of the piston rod, and the closer the oil-saving holes are to the second end of the throttle oil passage, the larger the hole diameter; the second end of the throttle oil passage is the outlet of the dark oil passage, and the The oil saving hole is the first end of the throttling oil passage. 15. The hydraulic oil cylinder according to any one of claims 1 to 8, characterized in that, the throttle oil passage is an oblique surface arranged axially on the surface of the piston rod, and the oblique surface is attached from the piston end to the piston rod. The direction of the end of the segment is inclined. 16. The hydraulic cylinder according to any one of claims 1 to 8, characterized in that, the sealed end surface of the rodless chamber is arranged on the end cover of the rodless chamber. 17. A hydraulic buffer system, characterized by comprising the hydraulic cylinder according to any one of claims 1-16. 18. An excavator, characterized in that at least one hydraulic cylinder according to any one of claims 1-16 is used. 19. A concrete pump truck, characterized in that at least one hydraulic cylinder according to any one of claims 1-16 is used.

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