Hydraulic cylinder capable of reciprocating at constant speed

Abstract

The utility model discloses a constant-speed reciprocating hydraulic cylinder which comprises a cylinder pipe, a rear cover and a flange are respectively fixed at two ends of the cylinder pipe, a piston and a piston shaft penetrating through the flange are arranged in a cavity of the cylinder pipe, an oil discharge nozzle and a second oil inlet and outlet nozzle which are communicated with the cavity of the cylinder pipe are respectively arranged on the cylinder pipe and the flange on two sides of the piston, and an inner shaft is mounted in the rear cover. The end, close to the rear cover, of the axial cavity of the inner shaft is closed, and the end, away from the rear cover, of the axial cavity of the inner shaft penetrates through the axial cavity of the inner shaft. The piston shaft is of a hollow structure, the inner shaft is sleeved with a piston of the piston shaft, and a plug is arranged at the end, away from the piston, of the piston shaft. A first cavity is formed between the inner shaft and the piston shaft, and a second cavity is formed among the piston, the piston shaft, the cylinder pipe and the flange. The speed that the first oil inlet and outlet nozzle injects oil into the first cavity through the axial cavity of the inner shaft to push the piston shaft to extend outwards is equal to the speed that the second oil inlet and outlet nozzle injects oil into the second cavity to push the piston shaft to contract inwards.

Description

Technical Field

[0001] The utility model relates to the technical field of structural improvement design of oil cylinders, in particular to a hydraulic cylinder with constant speed reciprocating motion. Background Art

[0002] Ordinary hydraulic cylinders have a piston rod extending from only one end. Due to the effective working area, the effective working area of ​​the piston chamber is not equal to the effective working area of ​​the piston rod chamber, resulting in a large difference in the volume of hydraulic oil required when the piston rod is extended and retracted, resulting in a slow speed on the side with a larger volume. Generally, the piston rod extends slowly and retracts quickly. This situation cannot meet the working requirements of mechanical equipment.

[0003] In the prior art, the patent with announcement number CN207879751U discloses a constant velocity oil cylinder, including a cylinder body, a piston rod, a first piston and a second piston, the piston rod is provided with a first guide sleeve, a second guide sleeve and a stop tube, the first piston, the stop tube and the second piston divide the cylinder body into a rod head end oil chamber and a cylinder bottom end oil chamber with equal pressure, the cylinder body, the first piston, the second piston, the stop tube and the rod head end oil chamber and the cylinder bottom end oil chamber form a sealing structure, the cylinder body is also provided with a first oil port seat, a second oil port seat and a third oil port seat, the first oil port seat and the second oil port seat are connected, the first oil port seat and the second oil port seat are connected with the cylinder bottom end oil chamber, the third oil port seat is connected with the rod head end oil chamber, the first oil port seat, the second oil port seat and the third oil port seat enter the hydraulic oil to push the first piston and the second piston to reciprocate to realize the constant velocity motion of the oil cylinder. Through the above method, the utility model constant velocity oil cylinder can achieve consistent extension and retraction speed, meet the use requirements, simple structure and long service life.

[0004] In the above technical solution, the contact area between the left side of the first piston 3 and the hydraulic oil is equal to the contact area between the right side of the second piston 4 and the hydraulic oil. Since the contact areas between the first piston 3 and the second piston 4 and the hydraulic oil are equal, the piston rod can extend and retract at the same speed. Since there are piston rods extending from both ends of the oil cylinder, two pistons need to be designed, and the overall structural design is relatively complicated.

[0005] In order to solve one of the above problems, the present application provides a hydraulic cylinder with constant speed reciprocating motion. Utility Model Content

[0006] The utility model aims to solve the problems existing in the prior art and proposes a hydraulic cylinder with constant speed reciprocating motion. Through improved design, the contact area of ​​the hydraulic oil is balanced in volume on both sides of the oil inlet and the oil outlet, the required amount of hydraulic oil is similar, and the machine can obtain a stable speed.

[0007] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a hydraulic cylinder with constant speed reciprocating motion, including a cylinder tube, a rear cover and a flange are respectively fixed at both ends of the cylinder tube, a piston and a corresponding piston shaft are arranged in the cavity of the cylinder tube, usually the piston is fixed on the end of the piston shaft, the piston shaft passes through the flange, the cylinder tube and the flange on both sides of the piston are respectively provided with an oil discharge nozzle and a second oil inlet and outlet nozzle connected to the cylinder tube cavity, the oil discharge nozzle is a three-point joint, and the second oil inlet and outlet nozzle is a six-point joint, an inner shaft with an axial cavity is installed in the rear cover, the axial cavity of the inner shaft close to one end of the rear cover is sealed, and the axial cavity of the inner shaft away from one end of the rear cover is penetrated, the first oil inlet and outlet nozzle installed on the rear cover is connected to the axial cavity of the inner shaft, and the first oil inlet and outlet nozzle is a six-point joint;

[0008] The piston shaft is a hollow structure, the piston sleeve of the piston shaft is arranged outside the inner shaft, and a plug is provided at one end of the piston shaft away from the piston, that is, the axial cavity of the inner shaft can be connected with the hollow structure of the piston shaft;

[0009] A first chamber is formed between the inner shaft and the piston shaft, which is used to connect to the first inlet and outlet oil nozzle. A second chamber is formed between the piston, the piston shaft, the cylinder tube and the flange, which is used to maintain communication with the second inlet and outlet oil nozzle. The speed at which the first inlet and outlet oil nozzle injects oil into the first chamber through the axial cavity of the inner shaft to push the piston shaft to extend outward is equal to the speed at which the second inlet and outlet oil nozzle injects oil into the second chamber to push the piston shaft to retract inward. On this basis, when the same supply source is connected externally, the inlet and outlet speeds of the piston shaft can be made equal without the need for other additional valve controls.

[0010] Furthermore, as described above, the cross-sectional area of ​​the first chamber is equal to the cross-sectional area of ​​the second chamber. Since the volumes of the two chambers are balanced and the required amounts of hydraulic oil are similar, the telescopic movement of the piston shaft can obtain a stable speed.

[0011] Furthermore, the inner shaft as described above passes through the back cover and is locked by a nut, the end of the inner shaft is processed with an external thread, the nut is processed with an internal thread, and the back cover is processed with a through-type stepped through hole for accommodating the inner shaft, so that the external thread section of the inner shaft is blocked and limited at the same time after passing through the through-type stepped through hole of the back cover, and then the inner shaft and the back cover can be locked by threading the inner shaft with the nut.

[0012] Furthermore, the inner shaft as described above is processed with a first through hole connected to the axial cavity, and the rear cover is processed with a first blind hole, in which a first oil inlet and outlet nozzle is installed and connected to the first through hole.

[0013] Furthermore, the piston shaft as described above is a cylinder with a central through hole, and the annular boss at one end of the cylinder forms a piston, that is, the piston and the piston shaft are an integrated structure, and the other end of the cylinder is internally connected to the front cover to form a blockage.

[0014] Furthermore, the piston shaft and the front cover as described above are threadedly connected, and a fixing pressure ring is provided on the outer sleeve of the front cover.

[0015] Furthermore, an oil path gap is formed between the inner wall of the flange and the piston shaft close to the piston.

[0016] Furthermore, a second blind hole is processed on the flange as described above, and a second oil inlet and outlet nozzle is installed in the second blind hole and is connected with the oil circuit gap.

[0017] Furthermore, one end of the flange as described above is sleeved in the cylinder tube and contacts the end surface of the cylinder tube, thereby increasing the contact area between the flange and the cylinder tube, leaving space for installing a sealing ring, and enhancing the sealing between the flange and the cylinder tube.

[0018] Furthermore, the flange and the rear cover as described above are connected and fixed by a tie rod.

[0019] Compared with the prior art, the beneficial effects of the utility model are: the overall structural design of the device is simple and ingenious, the first inlet and outlet nozzles enter the first chamber when injecting oil, and the cross-sectional area of ​​the first chamber determines the extension speed of the piston shaft, and the second inlet and outlet nozzles enter the second chamber when injecting oil, and the cross-sectional area of ​​the second chamber determines the contraction speed of the piston shaft. The cross-sectional area of ​​the first chamber and the second chamber of this oil cylinder is the same, and when connected to the same supply source, no other additional valve control is required to make the piston shaft in and out speeds equal. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional diagram of the utility model;

[0021] Figure 2 It is an explosion diagram of the utility model;

[0022] Figure 3 This is a front view of the utility model in an extended state;

[0023] Figure 4 for Figure 3 Sectional view in the AA direction;

[0024] Figure 5 This is a front view of the utility model in a retracted state;

[0025] Figure 6 for Figure 5 Cross-sectional view along the BB direction.

[0026] In the figure: 1, front cover; 2, fixed pressure ring; 3, piston shaft; 4, flange; 41, second oil inlet and outlet nozzle; 5, inner shaft; 6, nut; 7, cylinder tube; 71, oil drain port; 8, rear cover; 81, first oil inlet and outlet nozzle; 9, pull rod. DETAILED DESCRIPTION

[0027] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "fixed", "installed", "connected", "set", etc. should be understood in a broad sense. For example, when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can be a central element. When an element is considered to be "installed on" another element, it can be directly installed on the other element or there can be a central element. When an element is considered to be "connected" to another element, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a communication between the two elements.

[0029] For those skilled in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] Embodiment 1

[0032] Reference Figure 1-6As shown, a hydraulic cylinder with constant speed reciprocating motion of the utility model comprises a cylinder tube 7, a rear cover 8 and a flange 4 are fixed at both ends of the cylinder tube 7 respectively, a piston and a corresponding piston shaft 3 are arranged in the cavity of the cylinder tube 7, usually the piston is fixed on the end of the piston shaft 3, the piston shaft 3 passes through the flange 4, and an oil discharge nozzle and a second oil inlet and outlet nozzle 41 connected to the cavity of the cylinder tube 7 are respectively arranged on the cylinder tube 7 and the flange 4 on both sides of the piston, and the second oil inlet and outlet nozzle 41 is used to inject oil into the cavity of the cylinder tube 7 to push the piston to move, the oil discharge nozzle is a three-point joint, and the second oil inlet and outlet nozzle 41 is a six-point joint. Compared with the ordinary cylinder structure design, the improvement is that an inner shaft with an axial cavity is installed in the rear cover 8 5, that is, the axial cavity is processed in the direction of the central axis of the inner shaft 5. Specifically, the axial cavity of the inner shaft 5 close to the rear cover 8 is sealed, and the axial cavity of the inner shaft 5 away from the rear cover 8 is penetrated. The first inlet and outlet nozzles 81 installed on the rear cover 8 are connected to the axial cavity of the inner shaft 5, so that the oil can flow into the axial cavity of the inner shaft 5 after the first inlet and outlet nozzles 81 are filled with oil. The first inlet and outlet nozzles 81 are six-point joints; in addition, the piston shaft 3 is a hollow structure, and the piston sleeve of the piston shaft 3 is arranged outside the inner shaft 5. The piston shaft 3 is provided with a plug at the end away from the piston, that is, the axial cavity of the inner shaft 5 can be kept in communication with the hollow structure of the piston shaft 3, so that the oil filling of the first inlet and outlet nozzles 81 is obtained; in addition, referring to Figure 6 A first chamber is formed between the inner shaft 5 and the piston shaft 3 for communicating with the first inlet and outlet oil nozzle 81, and a second chamber is formed between the piston, the piston shaft 3, the cylinder tube 7 and the flange 4 for maintaining communication with the second inlet and outlet oil nozzle 41. The speed at which the first inlet and outlet oil nozzle 81 injects oil into the first chamber through the axial cavity of the inner shaft 5 to push the piston shaft 3 to extend outward is equal to the speed at which the second inlet and outlet oil nozzle 41 injects oil into the second chamber to push the piston shaft 3 to retract inward. In this way, when connected to the same supply source, the inlet and outlet speeds of the piston shaft 3 can be made equal without the need for other additional valve control.

[0033] Embodiment 2

[0034] Reference Figure 1-6 As shown, based on the technical solution of the first embodiment, a hydraulic cylinder with constant speed reciprocating motion, the principle of its improved design is that the cross-sectional area of ​​the first chamber is equal to the cross-sectional area of ​​the second chamber. As for the assembly structure design of the inner shaft 5, the inner shaft 5 passes through the rear cover 8 and is locked by the nut 6. Specifically, the end of the inner shaft 5 is processed with an external thread, the nut 6 is processed with an internal thread, and the rear cover 8 is processed with a through-type stepped through hole for accommodating the inner shaft 5, so that the external thread section of the inner shaft 5 is blocked and limited at the same time after passing through the through-type stepped through hole of the rear cover 8, and then the inner shaft 5 is threadedly connected with the nut 6 to lock the inner shaft 5 and the rear cover 8. In addition, a plurality of sealing rings are provided between the inner shaft 5 and the rear cover 8, and a plurality of sealing rings are also provided at the assembly part of the rear cover 8 and the cylinder tube 7 to increase the sealing performance.

[0035] As for the structural design of the inner shaft 5, a first through hole connected to the axial cavity is processed on the inner shaft 5. The first through hole can be connected to the axial cavity on one side or symmetrically on both sides. A first blind hole is processed on the rear cover 8. The first blind hole penetrates through the through-type step through hole of the rear cover 8 on one side and is connected. The first inlet and outlet oil nozzle 81 is installed in the first blind hole and is connected to the first through hole. That is, when installing the inner shaft 5, it is necessary to align the first blind hole so that the first blind hole is opposite to the first through hole. Positioning can be assisted by inserting a rod to insert the rod, and the minimum inner diameter of the rod matches the above two holes.

[0036] Embodiment 3

[0037] Reference Figure 1-6 As shown, based on the technical solution of the second embodiment, a hydraulic cylinder with constant speed reciprocating motion, for the specific structural design of the piston shaft 3, the piston shaft 3 is a cylinder with a central through hole, and the annular boss at one end of the cylinder forms a piston, that is, the piston and the piston shaft 3 are an integrated structure, and the other end of the cylinder is internally connected to the front cover 1 to form a blockage, that is, the cylinder inner cavity of the piston shaft 3 and the axial cavity of the inner shaft 5 and the first inlet and outlet nozzle 81 form a single-end opening cavity for oil injection or oil discharge. Specifically, the piston shaft 3 and the front cover 1 are threadedly connected, the front cover 1 is provided with a fixed pressure ring 2, one end of the piston shaft 3 is processed with an internal thread, and the front cover 1 is processed with an external thread, and the piston shaft 3 and the front cover 1 are fastened by threaded connection. In addition, multiple sealing rings are provided between the piston shaft 3 and the front cover 1, multiple sealing rings are provided between the inner shaft 5 and the piston shaft 3 to increase the sealing performance, multiple oil seals are provided between the piston and the cylinder tube 7, and multiple oil seals are provided between the piston rod and the flange 4 to increase the sealing performance during the reciprocating motion. Multiple annular grooves are respectively processed on the piston shaft 3 and the piston to install wear-resistant rings, so as to improve the wear resistance between the piston and the cylinder tube 7 or the piston rod and the flange 4 and increase the service life.

[0038] Furthermore, an oil gap is formed between the inner wall of the flange 4 and the piston shaft 3 near the piston, for the second oil inlet and outlet nozzle 41 to inject oil into the oil gap. In addition, a second blind hole is machined on the flange 4, and the second oil inlet and outlet nozzle 41 is installed in the second blind hole and communicated with the oil gap. Since the outer diameter of the piston shaft 3 is equal, in order to form the oil gap, the inner wall of the flange 4 between the second blind hole and the piston has an inner diameter greater than the outer diameter of the piston shaft 3 after machining.

[0039] Furthermore, one end of the flange 4 is sleeved in the cylinder tube 7 and contacts the end surface of the cylinder tube 7, increasing the contact area between the flange 4 and the cylinder tube 7, leaving a position for installing the sealing ring, and enhancing the sealing between the flange 4 and the cylinder tube 7. In addition, the flange 4 and the rear cover 8 are connected and fixed by tie rods 9, and the number of the tie rods is four and evenly distributed, so that the overall structure of the cylinder tube 7 is balanced and stable. Specifically, both ends of the tie rod 9 are respectively processed with external threads, wherein one end of the tie rod 9 is connected to the screw hole processed on the rear cover 8, and the other end of the tie rod 9 passes through the second through hole on the flange 4 and is locked by a nut and a spring washer, so that the flange 4, the cylinder tube 7 and the rear cover 8 are stably connected.

[0040] Working principle: the inner shaft 5 is fixed to the rear cover 8, and there is a first oil inlet and outlet channel at the rear cover 8 and the end face of the inner shaft 5, which is used to extend the piston shaft 3 of the oil cylinder; the piston shaft 3 has an oil seal installed at the piston to separate the hydraulic oil, and the center of the piston shaft 3 is a through hole, and the inner shaft 5 passes through the center of the piston shaft 3. After the oil is injected at the rear cover 8, it flows through the central through hole of the inner shaft 5 to the closed cavity formed by the piston shaft 3 and the inner shaft 5, and pushes the piston shaft 3 outward under the action of pressure. The first chamber and the second chamber are designed to have the same cross-sectional area without other controls to make the piston shaft 3 enter and exit at the same speed, and the space on both sides of the hydraulic cylinder can reach a similar value. It can be installed on the injection molding machine to make its mold opening and closing speed close to the same, the machine working speed is stable, and the hydraulic oil circuit is simplified.

[0041] In the device of the utility model, the assembly and matching relationship of the various components involved, the material and size design parameters of the components are selected according to needs, and the sealing rings, wear-resistant rings and oil seals are existing technologies or materials. The relevant technical personnel can directly purchase or customize them from the market according to the required product models and specifications.

[0042] The electrical components mentioned in the text are all connected to an external main controller and 220V mains or industrial electricity, and the main controller can be a conventional known device such as a computer that plays a control role.

[0043] The above is only a preferred specific embodiment of the utility model, and the common knowledge such as the known specific structure and characteristics in the scheme is not described too much here. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above-mentioned embodiment, and the utility model can be implemented in other specific forms without departing from the spirit or basic characteristics of the utility model. Therefore, no matter from which point of view, the embodiment should be regarded as exemplary and non-restrictive. Any technician familiar with the technical field within the technical scope disclosed by the utility model, according to the technical scheme of the utility model and its utility model concept, shall be covered within the protection scope of the utility model.

Claims

1. A hydraulic cylinder with constant speed reciprocating motion, comprising a cylinder tube (7), a rear cover (8) and a flange (4) are fixed to both ends of the cylinder tube (7), a piston and a corresponding piston shaft (3) are arranged in the cavity of the cylinder tube (7), the piston shaft (3) passes through the flange (4), and an oil discharge nozzle and a second oil inlet and outlet nozzle (41) communicating with the cavity of the cylinder tube (7) are respectively arranged on the cylinder tube (7) and the flange (4) on both sides of the piston, characterized in that: An inner shaft (5) with an axial cavity is installed in the rear cover (8), the axial cavity of the inner shaft (5) close to one end of the rear cover (8) is sealed, and the axial cavity of the inner shaft (5) away from one end of the rear cover (8) is penetrated, and a first oil inlet and outlet nozzle (81) installed on the rear cover (8) is connected to the axial cavity of the inner shaft (5); The piston shaft (3) is a hollow structure, the piston sleeve of the piston shaft (3) is arranged outside the inner shaft (5), and a plug is provided at one end of the piston shaft (3) away from the piston; A first chamber is formed between the inner shaft (5) and the piston shaft (3), and a second chamber is formed between the piston, the piston shaft (3), the cylinder tube (7) and the flange (4). The speed at which the first oil inlet and outlet nozzle (81) injects oil into the first chamber through the axial cavity of the inner shaft (5) to push the piston shaft (3) outward is equal to the speed at which the second oil inlet and outlet nozzle (41) injects oil into the second chamber to push the piston shaft (3) inward.

2. A hydraulic cylinder with constant reciprocating motion according to claim 1, characterized in that: The cross-sectional area of ​​the first chamber is equal to the cross-sectional area of ​​the second chamber.

3. A hydraulic cylinder with constant reciprocating motion according to claim 2, characterized in that: The inner shaft (5) passes through the rear cover (8) and is locked by a nut (6).

4. A hydraulic cylinder with constant reciprocating motion according to claim 3, characterized in that: The inner shaft (5) is processed with a first through hole connected to the axial cavity, and the rear cover (8) is processed with a first blind hole. The first inlet and outlet oil nozzle (81) is installed in the first blind hole and is connected to the first through hole.

5. The hydraulic cylinder with constant reciprocating motion according to claim 2, characterized in that: The piston shaft (3) is a cylinder with a central through hole, an annular boss at one end of the cylinder forms a piston, and the other end of the cylinder is internally connected to the front cover (1) to form a blockage.

6. A hydraulic cylinder with constant velocity reciprocating motion according to claim 5, characterized in that: The piston shaft (3) and the front cover (1) are threadedly connected, and a fixed pressure ring (2) is disposed on the outer sleeve of the front cover (1).

7. A hydraulic cylinder with constant velocity reciprocating motion according to claim 2, characterized in that: An oil path gap is formed between the inner wall of the flange (4) and the piston shaft (3) close to the piston.

8. A hydraulic cylinder with constant velocity reciprocating motion according to claim 7, characterized in that: A second blind hole is processed on the flange (4), and a second oil inlet and outlet nozzle (41) is installed in the second blind hole and is connected with the oil circuit gap.

9. A hydraulic cylinder with constant velocity reciprocating motion according to claim 8, characterized in that: One end of the flange (4) is sleeved in the cylinder tube (7) and contacts the end surface of the cylinder tube (7).

10. A hydraulic cylinder with constant velocity reciprocating motion according to any one of claims 1 to 9, characterized in that: The flange (4) and the rear cover (8) are connected and fixed via a pull rod (9).

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