Novel high-pressure hydraulic control valve
By using a combination of pneumatic components and an electrically controlled valve in the high-pressure hydraulic control valve, the functions of high-frequency and timing control are realized, which solves the problem of difficult to meet the needs of high-frequency and timing control in the prior art, and is suitable for high-pressure environments.
Patent Information
- Application Number
- CN202422348671.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-09-25
AI Technical Summary
The existing high-pressure hydraulic switch valves are difficult to meet the needs of opening and closing hydraulic circuits at high frequency, and cannot achieve timing control.
A new high-pressure hydraulic control valve is designed, using a combination of pneumatic components and an electric control valve. The cylinder acts on the valve core, and combines or separates it with the oil outlet to achieve opening and closing control, and timing control is achieved through the electric control valve.
It realizes the function of opening and closing hydraulic circuits at high frequency, has the ability to control timing, is suitable for high-pressure environments, and reduces maintenance costs.
Smart Images
Figure CN222977125U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of hydraulic valves, and in particular, to a new type of high-pressure hydraulic control valve. Background Art
[0002] A high-pressure hydraulic on-off valve is a valve designed specifically for controlling the flow of liquid in a high-pressure environment. It is mainly applied in hydraulic systems to achieve control functions such as starting, stopping, and flow switching of the system. Such valves can withstand relatively high working pressures and are commonly used in fields such as construction machinery, ships, petrochemical industry, metallurgy, electric power, and various heavy machinery. Most of the existing high-pressure hydraulic on-off valves adopt mechanical control, and sometimes it is difficult to meet the working conditions that require frequent opening and closing of the hydraulic circuit, and timing control cannot be achieved. Summary of the Utility Model
[0003] The technical problem to be solved by this application is to propose a new type of high-pressure hydraulic control valve in view of the above deficiencies of the prior art.
[0004] A new type of high-pressure hydraulic control valve includes: an outer valve body, a valve seat, a valve core, and a pneumatic component;
[0005] The outer valve body is provided with a first oil inlet channel and a first oil outlet channel;
[0006] The valve seat is integrally arranged in the outer valve body in a detachable manner. A valve cavity is arranged in the valve seat, and the valve core is slidably inserted into the valve cavity; an oil outlet is arranged at the bottom of the valve cavity; a second oil inlet channel is arranged on the valve seat, and the second oil inlet channel connects the first oil inlet channel and the valve cavity; the first oil outlet channel communicates with the oil outlet from the outside of the valve cavity; the second oil inlet channel forms an oil inlet opening on the side wall of the valve cavity; for the part of the valve cavity from the oil inlet opening leading downward to the oil outlet, a clearance space for the oil liquid to pass through is provided between the inner wall of the valve cavity and the valve core;
[0007] The pneumatic component includes a cylinder and an electromagnetic valve; the cylinder can act on the valve core to combine or separate the valve core from the oil outlet to close or open the oil outlet, thereby controlling the on-off between the first oil inlet channel and the first oil outlet channel; the electromagnetic valve is used to control the telescopic movement of the cylinder.
[0008] Optionally, a first fit for guiding the sliding of the valve core is provided between the side wall of the valve cavity and the valve core above the oil inlet opening; a second fit for guiding the sliding of the valve core is provided between the side wall of the valve cavity and the valve core below the oil inlet opening.
[0009] Optionally, at the second mating location, the side wall of the valve cavity is circular; the valve core is provided with alternating arc surfaces and flat surfaces along its circumferential direction, wherein a sliding fit is formed between the arc surface and the side wall of the valve cavity.
[0010] Optionally, the outer valve body includes an upper valve body and a lower valve body, the upper valve body and the lower valve body are detachably connected together, and the valve seat is defined by the upper valve body and the lower valve body from the upper and lower sides.
[0011] Optionally, the top of the valve cavity is an open structure with a top opening; a guide hole is provided on the upper valve body, and a pressure ejector rod is provided in the guide hole; the pressure ejector rod is in sliding fit with the guide hole; the pressure ejector rod corresponds to the position of the valve core, and its lower end abuts against the valve core; when the cylinder drives the pressure ejector rod to move downward, the pressure ejector rod can press down the valve core to make the valve core combine with the oil outlet.
[0012] Optionally, a first sealing fit is formed between the valve seat and the upper valve body around the top opening of the valve cavity; a second sealing fit is provided between the side wall of the valve cavity and the valve core at a position close to the top opening of the valve cavity;
[0013] A return oil passage is provided on the upper valve body, and the return oil passage communicates with the guide hole.
[0014] Optionally, the outer valve body further includes an outer support, and the outer support is fixed on the upper valve body and / or the lower valve body; the cylinder block of the cylinder is installed on the outer support.
[0015] Optionally, the outer valve body further includes a locking nut; the top of the locking nut has a circular inner flange and is provided with internal threads near the bottom; the inner flange of the locking nut abuts downward against the upper valve body, and a thread fit is formed between the internal threads of the locking nut and the lower valve body, and the valve seat is fixed between the upper valve body and the lower valve body through the thread fit.
[0016] Optionally, a thrust bearing is provided between the inner flange of the locking nut and the upper valve body to allow the locking nut to rotate relative to the upper valve body.
[0017] Optionally, the first oil inlet passage is arranged on the upper valve body; the first oil outlet passage is arranged on the lower valve body;
[0018] An oil inlet connector communicating with the first oil inlet passage is further provided on the upper valve body; an oil outlet connector communicating with the first oil outlet passage is provided on the lower valve body.
[0019] In the present application, the valve seat is integrally provided in the outer valve body in a detachable manner. The valve core is slidably inserted into the valve cavity of the valve seat. The cylinder can act on the valve core to combine or separate the valve core from the oil outlet so as to close or open the oil outlet. A high-precision needle valve can be formed between the valve core and the valve seat, which is suitable for high-pressure hydraulic fluid. By controlling the action of the cylinder through an electromagnetic control valve, the hydraulic circuit can be controlled more flexibly. For example, the hydraulic circuit can be opened and closed frequently and controlled regularly. In addition, the valve seat is provided independently of the outer valve body, and when damaged, the internal valve seat and valve core can be replaced separately, with lower cost. Description of the Drawings
[0020] Figure 1 is a schematic structural view of the novel high-pressure hydraulic control valve in the embodiment of the present application.
[0021] Figure 2 is another schematic structural view of the novel high-pressure hydraulic control valve in the embodiment of the present application.
[0022] Figure 3 is a partial schematic structural view of the novel high-pressure hydraulic control valve in the embodiment of the present application.
[0023] Figure 4 is a schematic cross-sectional view of the side wall of the valve cavity and the valve core at the second mating position in the embodiment of the present application.
[0024] Figure 5 is a schematic block diagram of the novel high-pressure hydraulic control valve in the embodiment of the present application.
[0025] Reference Numerals:
[0026] Outer valve body 10, upper valve body 11, first oil inlet passage 111, guide hole 112, pressure ejector rod 113, oil return passage 114, lower valve body 12, first oil outlet passage 121, outer support 13, locking nut 14, inner flange 141, thrust bearing 15, oil inlet joint 16, oil outlet joint 17, valve seat 20, valve cavity 21, oil outlet 22, top opening 23, second oil inlet passage 24, oil inlet opening 25, valve core 30, arc surface 31, flat surface 32, pneumatic assembly 40, cylinder 41, electromagnetic control valve 42, first mating position P1, second mating position P2, first sealing mating position P3, second sealing mating position P4. Detailed Description of the Embodiment
[0027] The following are specific embodiments of the present application. In combination with the accompanying drawings, the technical solutions of the present application will be further described, but the present application is not limited to these embodiments. In the following description, specific details such as specific configurations and components are provided only to help comprehensively understand the embodiments of the present application. Therefore, those skilled in the art should clearly understand that various changes and modifications can be made to the embodiments described here without departing from the scope and spirit of the present application. In addition, descriptions of known functions and configurations are omitted for clarity and conciseness.
[0028] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.
[0029] The present application provides a new type of high-pressure hydraulic control valve, which can be applied to a hydraulic system to achieve control functions such as starting, stopping, and flow switching of the system. Specific descriptions will be given below in combination with the accompanying drawings.
[0030] Reference Figure 1 , the new type of high-pressure hydraulic control valve includes an outer valve body 10, a valve seat 20, a valve core 30, and a pneumatic component 40. The outer valve body 10 is provided with a first oil inlet passage 111 and a first oil outlet passage 121. The first oil inlet passage 111 is used for oil inlet, and the first oil outlet passage 121 is used for oil outlet.
[0031] Reference Figure 1 and Figure 2 , the valve seat 20 is integrally arranged in the outer valve body 10 in a detachable manner. The valve seat 20 is provided with a valve cavity 21, and the valve core 30 is slidably inserted into the valve cavity 21; an oil outlet 22 is provided at the bottom of the valve cavity 21; the valve seat 20 is provided with a second oil inlet passage 24, and the second oil inlet passage 24 connects the first oil inlet passage 111 and the valve cavity 21; the first oil outlet passage 121 communicates with the oil outlet 22 from the outside of the valve cavity 21; the second oil inlet passage 24 forms an oil inlet opening 25 on the side wall of the valve cavity 21; for the part of the valve cavity 21 leading from the oil inlet opening 25 downward to the oil outlet 22, there is a clearance space for the oil liquid to pass between the inner wall of the valve cavity 21 and the valve core 30. Further, the pneumatic component 40 includes a cylinder 41 and an electromagnetic valve 42; the cylinder 41 can act on the valve core 30 to combine or separate the valve core 30 from the oil outlet 22 to close or open the oil outlet 22, thereby controlling the on-off between the first oil inlet passage 111 and the first oil outlet passage 121; the electromagnetic valve 42 is used to control the telescopic action of the cylinder 41.
[0032] During operation, the first oil inlet passage 111 and the first oil outlet passage 121 are externally connected to a hydraulic system. The hydraulic oil enters from the first oil inlet passage 111 of the outer valve body 10 and passes through the first oil inlet passage 111 into the second oil inlet passage 24 on the valve seat 20. Then, the hydraulic oil in the second oil inlet passage 24 enters the valve cavity 21 through the oil inlet opening 25 on the side wall of the valve cavity 21. The oil in the valve cavity 21 reaches the oil outlet 22 through the clearance space between the inner wall of the valve cavity 21 and the valve core 30. When the valve core 30 is separated from the oil outlet 22, the oil outlet 22 opens, and the hydraulic oil in the valve cavity 21 can enter the first oil outlet passage 121 from the oil outlet 22. The first oil outlet passage 121 can output the hydraulic oil externally. At this time, the control valve is opened. When the valve core 30 is combined with the oil outlet 22, the oil outlet 22 is closed, and the hydraulic oil in the valve cavity 21 cannot enter the first oil outlet passage 121. At this time, the control valve is closed.
[0033] Furthermore, the pneumatic component 40 includes a cylinder 41 and an electromagnetic control valve 42. The cylinder 41 is controlled by the electromagnetic control valve 42, and the electromagnetic control valve 42 can be controlled by the electrical signal of the controller. Therefore, the controller can control the telescopic movement of the cylinder 41 through the electromagnetic control valve 42 to quickly open and close the new high-pressure hydraulic control valve, as well as regularly open and close the new high-pressure hydraulic control valve. Further, the electromagnetic control valve 42 is specifically a solenoid valve. In the embodiment of the present application, a high-precision needle valve can be formed between the valve core 30 and the valve seat 20, which is suitable for high-pressure oil. By controlling the movement of the cylinder 41 through the electromagnetic control valve 42, the hydraulic circuit can be controlled more flexibly. For example, the hydraulic circuit can be opened and closed frequently and controlled regularly. In some other alternative embodiments, the electromagnetic control valve 42 can be used in combination with a timer to achieve timed opening or closing.
[0034] In Figure 1 and Figure 2 the shown structure, the first oil outlet passage 121 communicates with the oil outlet 22 from the outside of the valve cavity 21. Therefore, the hydraulic oil in the valve cavity 21 enters the first oil outlet passage 121 after being discharged through the oil outlet 22 to discharge the new high-pressure hydraulic control valve.
[0035] In addition, it should be understood that for the new high-pressure hydraulic control valve provided in the embodiment of the present application, the valve seat is independently arranged from the outer valve body. When damaged, the internal valve seat and valve core can be replaced separately, with lower cost. During processing, only the valve seat and valve core inside the valve body need to be processed with high precision, and the internal channels of the valve are separately arranged on the outer valve body and the valve seat, reducing the processing difficulty.
[0036] Reference Figure 3, in an embodiment of the present application, above the oil inlet opening 25, a first fit P1 capable of guiding the sliding of the valve core 30 is provided between the side wall of the valve cavity 21 and the valve core 30; below the oil inlet opening 25, a second fit P2 capable of guiding the sliding of the valve core 30 is provided between the side wall of the valve cavity 21 and the valve core 30.
[0037] Specifically, the first fit P1 and the second fit P2 are respectively arranged on the upper and lower sides of the oil inlet opening 25. Both the first fit P1 and the second fit P2 can be used to guide the sliding of the valve core 30, which can avoid the excessive length of the non-guided suspended part on the valve core 30, better resist the eccentric force acting on the valve core, and reduce wear. Therefore, under the joint guidance of the first fit P1 and the second fit P2, the sliding of the valve core 30 is more stable.
[0038] Reference Figure 4 , in an embodiment of the present application, at the second fit, the side wall of the valve cavity 21 is circular; the valve core 30 is provided with alternating arc surfaces 31 and flat surfaces 32 along its circumferential direction. Among them, a sliding fit is formed between the arc surface 31 and the side wall of the valve cavity 21.
[0039] Specifically, the second fit is arranged below the oil inlet opening 25, and in the part of the valve cavity 21 leading from the oil inlet opening 25 downward to the oil outlet 22, there is a clearance space for the oil liquid to pass between the inner wall of the valve cavity 21 and the valve core 30. Therefore, at the second fit, the side wall of the valve cavity 21 needs to guide the sliding of the valve core 30 and at the same time provide a clearance space for the oil liquid to pass. In the above design, the valve core 30 is provided with alternating arc surfaces 31 and flat surfaces 32 along its circumferential direction. Among them, a sliding fit is formed between the arc surface 31 and the side wall of the valve cavity 21 to form a first fit P1 capable of guiding the sliding of the valve core 30, while there is a clearance space for the oil liquid to pass between the flat surface 32 and the side wall of the valve cavity 21.
[0040] In an embodiment of the present application, the outer valve body 10 includes an upper valve body 11 and a lower valve body 12, and the upper valve body 11 and the lower valve body 12 are detachably connected together, and the valve seat 20 is defined by the upper valve body 11 and the lower valve body 12 from the upper and lower sides. In this design, since the upper valve body 11 and the lower valve body 12 are detachable, the maintenance is simpler, and it is convenient to quickly maintain and replace the valve seat and the valve core. In an embodiment of the present application, the outer valve body 10 further includes an outer support 13, and the outer support 13 is fixed on the upper valve body 11 and / or the lower valve body 12; the cylinder body of the cylinder 41 is installed on the outer support 13.
[0041] Reference Figures 1-3, the top of the valve cavity 21 is an open structure with a top opening 23; a guide hole 112 is provided on the upper valve body 11, and a pressure ejector rod 113 is provided in the guide hole 112; the pressure ejector rod 113 is slidably matched with the guide hole 112; the pressure ejector rod 113 corresponds to the position of the valve core 30, and its lower end abuts against the valve core 30; when the air cylinder 41 drives the pressure ejector rod 113 to move downward, the pressure ejector rod 113 can press down the valve core 30 to make the valve core 30 combine with the oil outlet 22. At the same time, refer to Figure 5 , during operation, when the air cylinder 41 extends, it first drives the pressure ejector rod 113 to move downward, and the pressure ejector rod 113 presses against the valve core 30 to make it combine with the oil outlet 22. When the air cylinder 41 contracts, it can be separated from the pressure ejector rod 113, and the valve core 30 moves upward under the oil pressure and drives the pressure ejector rod 113 to move upward.
[0042] Refer to Figure 3 , in an embodiment of the present application, around the top opening 23 of the valve cavity 21 for one week, a first sealing fit P3 is formed between the valve seat 20 and the upper valve body 11; at a position close to the top opening 23 of the valve cavity 21, a second sealing fit P4 is provided between the side wall of the valve cavity 21 and the valve core 30; an oil return passage 114 is provided on the upper valve body 11, and the oil return passage 114 is communicated with the guide hole 112. In Figure 3 the structure shown, the first fit P1 and the second sealing fit P4 are fits at the same part and have the functions of sealing and guiding at the same time. When the oil in the valve cavity 21 leaks into the guide hole 112 of the upper valve body 11, the oil return passage 114 can discharge the oil leaked into the guide hole 112.
[0043] Refer to Figure 1 and Figure 2 , in an embodiment of the present application, the outer valve body 10 further includes a locking nut 14; there is a circle of inner flange 141 at the top of the locking nut 14, and internal threads are provided at a position close to the bottom; the inner flange of the locking nut 14 abuts downward against the upper valve body 11, and a threaded fit is formed between the internal threads of the locking nut 14 and the lower valve body 12, and the valve seat 20 is fixed between the upper valve body 11 and the lower valve body 12 through the threaded fit. Specifically, during installation, the locking nut 14 is sleeved downward on the upper valve body 11, and the locking nut 14 is tightly combined with the lower valve body 12 through threaded fit by rotating the locking nut 14, and presses the upper valve body 11 downward, so that the upper valve body 11 and the lower valve body 12 fix the valve seat 20 therebetween. In an embodiment of the present application, a thrust bearing 15 is provided between the inner flange of the locking nut 14 and the upper valve body 11 to allow the locking nut 14 to rotate relative to the upper valve body 11. Under this design, the thrust bearing 15 allows the locking nut 14 to rotate relative to the upper valve body 11. Therefore, when the locking nut 14 is screwed onto the lower valve body 12, the locking nut 14 will not drive the upper valve body 11 to rotate. Thus, the upper valve body 11 can be kept relatively stationary with the valve seat 20, so as to keep the internal hole positions aligned.
[0044] In an embodiment of the present application, the first oil inlet passage 111 is arranged on the upper valve body 11; the first oil outlet passage 121 is arranged on the lower valve body 12; an oil inlet joint 16 communicating with the first oil inlet passage 111 is further provided on the upper valve body 11; and an oil outlet joint 17 communicating with the first oil outlet passage 121 is provided on the lower valve body 12.
[0045] In an embodiment of the present application, the valve seat is integrally arranged in the outer valve body in a detachable manner, the valve core is slidably inserted into the valve cavity of the valve seat, and the cylinder can act on the valve core to combine or separate the valve core from the oil outlet to close or open the oil outlet. A high-precision needle valve can be formed between the valve core and the valve seat, which is suitable for high-pressure oil. Moreover, by controlling the action of the cylinder through an electromagnetic valve, the hydraulic circuit can be controlled more flexibly. For example, the hydraulic circuit can be opened and closed frequently and timed controlled. In addition, by arranging the valve seat independently of the outer valve body, the internal valve seat and valve core can be replaced separately when damaged, and the cost is lower. In addition, for the novel high-pressure hydraulic control valve provided in the embodiment of the present application, by arranging the valve seat independently of the outer valve body, the internal valve seat and valve core can be replaced separately when damaged, and the cost is lower. During processing, only the valve seat and valve core inside the valve body need to be processed with high precision, and the internal channels of the valve are separately arranged on the outer valve body and the valve seat, reducing the processing difficulty.
[0046] In the above embodiments of the present application, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.
[0047] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined. It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0048] The specific embodiments described herein are only illustrative examples of the technical solutions of the present application. Those skilled in the technical field to which the present application pertains can make various modifications or supplements to the described specific embodiments or use similar methods to replace them, but will not deviate from the scope defined by the claims of the present application.
Claims
1. A new type of high pressure hydraulic control valve, characterized in that: include: Outer valve body, valve seat, valve core, pneumatic components; The outer valve body is provided with a first oil inlet channel and a first oil outlet channel; The valve seat is detachably integrated in the outer valve body, a valve cavity is provided in the valve seat, and the valve core can be slidably inserted into the valve cavity; an oil outlet is provided at the bottom of the valve cavity; a second oil inlet channel is provided on the valve seat, and the second oil inlet channel connects the first oil inlet channel and the valve cavity; the first oil outlet channel is connected to the oil outlet from the outside of the valve cavity; the second oil inlet channel forms an oil inlet opening on the side wall of the valve cavity; for the valve cavity portion extending downward from the oil inlet opening to the oil outlet, a gap space for oil to pass through is provided between the inner wall of the valve cavity and the valve core; The pneumatic assembly includes a cylinder and an electric control valve; the cylinder can act on the valve core to make the valve core and the oil outlet be combined or separated to close or open the oil outlet, thereby controlling the connection between the first oil inlet channel and the first oil outlet channel; The electric control valve is used to control the extension and retraction action of the cylinder.
2. The new high-pressure hydraulic control valve according to claim 1 is characterized in that: On the upper side of the oil inlet opening, a first fit capable of guiding the valve core to slide is provided between the side wall of the valve cavity and the valve core; on the lower side of the oil inlet opening, a second fit capable of guiding the valve core to slide is provided between the side wall of the valve cavity and the valve core.
3. The new high-pressure hydraulic control valve according to claim 2 is characterized in that: At the second fitting position, the side wall of the valve cavity is circular; the valve core is provided with alternating arc surfaces and flat surfaces along its circumference, wherein a sliding fit is formed between the arc surfaces and the side wall of the valve cavity.
4. The new high-pressure hydraulic control valve according to any one of claims 1 to 3, characterized in that: The outer valve body comprises an upper valve body and a lower valve body, wherein the upper valve body and the lower valve body are detachably connected together, and the valve seat is limited by the upper valve body and the lower valve body from upper and lower sides.
5. The new high-pressure hydraulic control valve according to claim 4 is characterized in that: The top of the valve cavity is an open structure with a top opening; a guide hole is provided on the upper valve body, and a pressure push rod is provided in the guide hole; the pressure push rod is slidably matched with the guide hole; the pressure push rod corresponds to the position of the valve core, and its lower end abuts against the valve core; when the cylinder drives the pressure push rod to move downward, the pressure push rod can press down the valve core so that the valve core is combined with the oil outlet.
6. The new high-pressure hydraulic control valve according to claim 5 is characterized in that: A first sealing fit is formed between the valve seat and the upper valve body around the top opening of the valve cavity; a second sealing fit is provided between the side wall of the valve cavity and the valve core at a position close to the top opening of the valve cavity; The upper valve body is provided with an oil return passage, and the oil return passage is communicated with the guide hole.
7. The new high-pressure hydraulic control valve according to claim 4 is characterized in that: The outer valve body further comprises an outer support, and the outer support is fixed on the upper valve body and / or the lower valve body; the cylinder body of the cylinder is mounted on the outer support.
8. The new high-pressure hydraulic control valve according to claim 4 is characterized in that: The outer valve body also includes a locking nut; the top of the locking nut has an inner flange and an internal thread near the bottom; the inner flange of the locking nut abuts downward against the upper valve body, and the internal thread of the locking nut forms a threaded fit with the lower valve body, and the valve seat is fixed between the upper valve body and the lower valve body through the threaded fit.
9. The new high-pressure hydraulic control valve according to claim 8 is characterized in that: A thrust bearing is provided between the inner flange of the locking nut and the upper valve body to allow the locking nut to rotate relative to the upper valve body.
10. The new high-pressure hydraulic control valve according to claim 4, characterized in that: The first oil inlet passage is arranged on the upper valve body; the first oil outlet passage is arranged on the lower valve body; The upper valve body is also provided with an oil inlet joint communicating with the first oil inlet passage; the lower valve body is provided with an oil outlet joint communicating with the first oil outlet passage.