Stop valve

Abstract

The stop valve comprises a valve body, a hand wheel, a transmission mechanism and a valve rod, an installation hole is formed in the valve body, two inlet and outlet holes communicated with the installation hole respectively are further formed in the valve body, the hand wheel is connected with the head end of the valve rod through the transmission mechanism, and the tail end of the valve rod is sequentially sleeved with an inner valve element, an outer valve element and a movable valve seat from inside to outside. When the valve rod pushes the outer valve element and the inner valve element to move towards the tail end, the outer valve element and the inner valve element make contact with the first sealing face and the second sealing face of the movable valve seat in a sealed mode respectively so as to isolate the two inlet and outlet holes, and when the valve rod pushes the inner valve element and the outer valve element to move towards the head end, the movable valve seat is sealed. The inner valve element and the outer valve element leave the second sealing face and the first sealing face respectively so that the two inlet and outlet holes can be communicated. The movable valve seat, the inner valve element and the outer valve element form two sets of sealing faces, double sealing of the stop valve is achieved, the sealing effect, stability and reliability are improved, the service life is prolonged, and normal work of a whole system is guaranteed.

Description

Technical Field

[0001] The utility model relates to the field of valves, in particular to a stop valve. Background Art

[0002] As a common valve, the stop valve is widely used in many fields. Its stability and reliability can ensure the stability and safety of the overall system. In the prior art, the valve stem is driven to move by a hand wheel, so that the sealing surface between the valve core and the valve seat is in contact or separated, so as to close and conduct the stop valve.

[0003] However, the existing stop valve has only one set of sealing surfaces, which is prone to failure. Once failed, the stop valve cannot work properly, which affects the normal operation of the entire system, has low stability and reliability, and has a short service life.

[0004] Furthermore, the valve seat and the valve body of the existing stop valve are integrally arranged with the valve body by welding, and it is inconvenient to repair and replace them if they are damaged.

[0005] Therefore, how to provide a stable and reliable stop valve is a technical problem that technicians in this field currently need to solve. Utility Model Content

[0006] The utility model aims to provide a stop valve, which forms two sets of sealing surfaces through a movable valve seat, an inner valve core and an outer valve core, thereby realizing double sealing of the stop valve, improving the sealing effect, improving stability and reliability, increasing service life, and ensuring the normal operation of the overall system.

[0007] In order to solve the above technical problems, the utility model provides a stop valve, including a valve body, a handwheel, a transmission mechanism and a valve stem, the valve body is provided with a mounting hole, the valve body is also provided with two inlet and outlet holes respectively connected to the mounting hole, the handwheel is connected to the head end of the valve stem through the transmission mechanism, the end of the valve stem is sequentially provided with an inner valve core, an outer valve core and a movable valve seat from the inside to the outside, the movable valve seat is installed in the mounting hole, when the valve stem pushes the outer valve core and the inner valve core to move toward the end, the outer valve core and the inner valve core respectively seal and contact the first sealing surface and the second sealing surface of the movable valve seat to isolate the two inlet and outlet holes, when the valve stem pushes the inner valve core and the outer valve core to move toward the head end, the inner valve core and the outer valve core respectively leave the second sealing surface and the first sealing surface to connect the two inlet and outlet holes.

[0008] Preferably, the mounting hole extends along the axis, the two inlet and outlet holes are connected to the openings of the side wall of the mounting hole and are axially staggered, the movable valve seat is located between the two openings, an axially extending stepped hole is provided in the movable valve seat, the head end diameter of the stepped hole is larger than the end diameter, the outer valve core and the inner valve core are inserted into the stepped hole, the ports of the stepped hole are respectively connected to the two openings, the step surface in the middle of the stepped hole is the first sealing surface, and the conical surface of the head end port of the stepped hole is the second sealing surface.

[0009] Preferably, an inner guide hole is provided at the front end of the inner valve core, an inner guide column is provided at the rear end of the inner valve core, an outer guide hole is provided at the front end of the outer valve core, an outer guide column is provided at the rear end of the outer valve core, the end of the valve stem is fixedly installed in the inner guide hole, the inner guide column is inserted into the outer guide hole and the outer guide column is inserted into the end of the stepped hole, and can move relative to each other in the axial direction.

[0010] Preferably, the terminal end surface of the outer valve core is a third sealing surface in contact with the first sealing surface, and the conical surface on the outer periphery of the terminal end of the inner valve core is a fourth sealing surface in contact with the second sealing surface.

[0011] Preferably, a spring is arranged between the terminal end face of the inner valve core and the head end face of the outer valve core, an axially extending slide groove is arranged on the inner guide column, and a radially extending fixing pin is arranged in the outer guide hole, and the inner guide column and the outer guide hole are movably connected through the slide groove and the fixing pin.

[0012] Preferably, an annular groove is provided on the outer periphery of the valve stem end, and a semi-open ring is pressed against the inner side of the inner guide hole by an inner nut, and the semi-open ring is embedded in the annular groove.

[0013] Preferably, a cage is installed in the installation hole, the front end of the cage is connected to the valve body by bolts, and the rear end of the cage presses the movable valve seat.

[0014] Preferably, a pressing sleeve, a pressing plate and an anti-rotation clip are sequentially arranged at the front end of the cage sleeve.

[0015] Preferably, the transmission mechanism comprises a spline shaft and a spline sleeve, the handwheel is connected to the head end of the spline shaft, the end of the spline shaft is connected to the head end of the spline sleeve, and the end of the spline sleeve is threadedly connected to the head end of the valve stem.

[0016] Preferably, the valve body is provided with an axially extending support rod at the front end, a middle plate is installed at the front end of the support rod, the spline sleeve passes through the middle plate and is connected through a middle bearing, the middle plate is provided with an axially extending support rod at the front end, a top plate is installed at the front end of the support rod, the spline bearing passes through the top plate and is connected through a top bearing.

[0017] The utility model provides a stop valve, including a valve body, a hand wheel, a transmission mechanism and a valve stem. A mounting hole is provided in the valve body, and two inlet and outlet holes respectively connected to the mounting hole are also provided in the valve body. The hand wheel is connected to the head end of the valve stem through the transmission mechanism. The end of the valve stem is sequentially provided with an inner valve core, an outer valve core and a movable valve seat from the inside to the outside. The movable valve seat is installed in the mounting hole. When the valve stem pushes the outer valve core and the inner valve core to move toward the end, the outer valve core and the inner valve core respectively seal and contact the first sealing surface and the second sealing surface of the movable valve seat to isolate the two inlet and outlet holes. When the valve stem pushes the inner valve core and the outer valve core to move toward the head end, the inner valve core and the outer valve core respectively leave the second sealing surface and the first sealing surface to conduct the two inlet and outlet holes. Two sets of sealing surfaces are formed by the movable valve seat, the inner valve core and the outer valve core, so as to realize the double sealing of the stop valve, improve the sealing effect, improve the stability and reliability, increase the service life, and ensure the normal operation of the overall system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic structural diagram of a specific implementation of the stop valve provided by the utility model;

[0019] Figure 2 A partial enlarged view of the sealing surface of a specific implementation of the stop valve provided by the utility model;

[0020] Figure 3 A schematic diagram of the structure of an inner valve core in a specific implementation of the stop valve provided by the utility model;

[0021] Figure 4 A schematic structural diagram of an outer valve core in a specific implementation of the stop valve provided by the utility model;

[0022] Figure 5 This is a structural schematic diagram of a movable valve seat in a specific implementation manner of the stop valve provided by the utility model.

[0023] Among them, valve body 1, mounting hole 1-1, inlet and outlet holes 1-2, handwheel 2, valve stem 3, annular groove 3-1, inner valve core 4, inner guide hole 4-1, inner guide column 4-2, fourth sealing surface 4-3, slide groove 4-4, outer valve core 5, outer guide hole 5-1, outer guide column 5-2, third sealing surface 5-3, movable valve seat 6, first sealing surface 6-1, second sealing surface 6-2, stepped hole 6-3, spring 7, fixing pin 8, inner nut 9, semi-open ring 10, gasket 11, cage sleeve 12, pressure sleeve 13, pressure plate 14, anti-rotation card 15, packing 16, spline shaft 17, spline sleeve 18, support rod 19, middle plate 20, middle bearing 20-1, support rod 21, top plate 22, top bearing 22-1. DETAILED DESCRIPTION

[0024] The core of the utility model is to provide a stop valve, which forms two sets of sealing surfaces through a movable valve seat, an inner valve core and an outer valve core, thereby realizing double sealing of the stop valve, improving the sealing effect, improving stability and reliability, increasing service life, and ensuring the normal operation of the overall system.

[0025] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0026] Please refer to Figure 1 and Figure 2 , Figure 1 A schematic structural diagram of a specific implementation of the stop valve provided by the utility model; Figure 2 This is a partial enlarged view of the sealing surface of a specific implementation manner of the stop valve provided by the utility model.

[0027] The utility model provides a stop valve in a specific embodiment, including a valve body 1, a hand wheel 2, a transmission mechanism and a valve stem 3. A mounting hole 1-1 is provided in the valve body 1. It is defined that the end of each component close to the hand wheel 2 is the head end, and the end close to the valve body 1 is the tail end. The head end and the tail end of the valve body 1 are also extended with other components. In the contents shown in the drawings, the upper end is the head end and the lower end is the tail end. The mounting hole 11 extends axially, the head end opening is located at the head end face of the valve body 1, and the tail end opening is closed and located in the middle of the valve body 1. At the same time, two inlet and outlet holes 1-2 are also provided in the valve body 1. The inner end ports of the two inlet and outlet holes 1-2 are connected to the mounting hole 1-1, and the outer end ports of the two inlet and outlet holes 1-2 are arranged on opposite sides of the outer periphery of the valve body 1. The outer end openings of the two inlet and outlet holes 1-2 are used to connect the liquid inlet pipe and the liquid outlet pipe. When the liquid flows, it flows through the liquid inlet pipe, one inlet and outlet hole 1-2, the mounting hole 1-1, the other inlet and outlet hole 1-2 and the liquid outlet pipe in sequence.

[0028] The hand wheel 2 is connected to the head end of the valve stem 3 through a transmission mechanism. The end of the valve stem 3 is covered with an inner valve core 4, the outer end of the inner valve core 4 is covered with an outer valve core 5, and the outer end of the outer valve core 5 is covered with a movable valve seat 6. At the same time, the movable valve seat 6 is installed in the installation hole 1-1. The movable valve seat 6 is located between the inner end openings of the two inlet and outlet holes 1-2 and is an important component for isolating the two inlet and outlet holes 1-2. When the hand wheel 2 is turned forward, the valve stem 3 is driven to move axially toward the end through the transmission mechanism. Further, when the valve stem 3 pushes the outer valve core 5 and the inner valve core 4 to move toward the end, the outer valve core 5 seals and contacts the first sealing surface 6-1 of the movable valve seat 6, and the inner valve core 4 seals and contacts the second sealing surface 6-2 of the movable valve seat 6, forming two sets of sealing surfaces to isolate the two inlet and outlet holes 1-2. When the hand wheel 2 is rotated in the opposite direction, the valve stem 3 is driven to move axially toward the head end through the transmission mechanism. Further, when the valve stem 3 pushes the inner valve core 4 and the outer valve core 5 to move toward the head end, the inner valve core 4 separates the second sealing surface 6-2, and the outer valve core 5 separates the first sealing surface 6-1 to connect the two inlet and outlet holes 1-2.

[0029] Two sets of sealing surfaces are formed by the movable valve seat 6, the inner valve core 4 and the outer valve core 5 to achieve double sealing of the stop valve. Compared with the single sealing of the traditional stop valve, a double sealing structure is provided. Even if some parts are damaged, the stop valve can still continue to be used, thereby improving the sealing effect, improving stability and reliability, increasing service life, and ensuring the normal operation of the overall system.

[0030] Please refer to Figures 3 to 5 , Figure 3 A schematic diagram of the structure of an inner valve core in a specific implementation of the stop valve provided by the utility model; Figure 4 A schematic structural diagram of an outer valve core in a specific implementation of the stop valve provided by the utility model; Figure 5 This is a structural schematic diagram of a movable valve seat in a specific implementation manner of the stop valve provided by the utility model.

[0031] Preferably, the mounting hole 1-1 extends along the axis, the inner end openings of the two inlet and outlet holes 1-2 connected to the side wall of the mounting hole 1-1 are staggered along the axial direction, and the movable valve seat 6 is located between the two openings, so that the liquid flowing through the stop valve must flow through the movable valve seat 6. Specifically, if the two inlet and outlet holes 1-2 extend radially completely perpendicular to the axial direction, the outer end openings of the two inlet and outlet holes 1-2 are also staggered and no longer on the same straight line. Therefore, the inlet and outlet hole 1-2 located at the top is tilted downward, and the inlet and outlet hole 1-2 located at the bottom is tilted upward, so that the outer end openings of the two inlet and outlet holes 1-2 are on the same straight line, making the stop valve installation more convenient and the layout more reasonable.

[0032] Among them, an axially extending stepped hole 6-3 is provided in the movable valve seat 6, the head end diameter of the stepped hole 6-3 is larger than the tail end diameter, the outer valve core 5 and the inner valve core 4 are inserted into the stepped hole 6-3, the head end port of the stepped hole 6-3 is connected to the inner end opening of one inlet and outlet hole 1-2, and the tail end port of the stepped hole 6-3 is connected to the inner end opening of another inlet and outlet hole 1-2. The outer wall of the movable valve seat 6 is tightly fitted to the inner wall of the mounting hole 1-1, so that the stepped hole 6-3 serves as the only channel for liquid circulation. The step surface in the middle of the stepped hole 6-3 is the first sealing surface 6-1, and the conical surface of the head end port of the stepped hole 6-3 is the second sealing surface 6-2.

[0033] Furthermore, the inner valve core 4 is provided with an inner guide hole 4-1 at the head end, the inner valve core 4 is provided with an inner guide column 4-2 at the end, the outer valve core 5 is provided with an outer guide hole 5-1 at the head end, the outer valve core 5 is provided with an outer guide column 5-2 at the end, the end of the valve stem 3 is fixedly installed in the inner guide hole 4-1, the inner guide column 4-2 is inserted into the outer guide hole 5-1, so that the two can move relative to each other in the axial direction, and the outer guide column 5-2 is inserted into the end of the stepped hole 6-3, so that the two can move relative to each other in the axial direction. The end surface of the outer valve core 5 is the third sealing surface 5-3 in contact with the first sealing surface 6-1, and the conical surface on the outer periphery of the end of the inner valve core 4 is the fourth sealing surface 4-3 in contact with the second sealing surface 6-2.

[0034] In order to realize the step-by-step movement of the inner valve core 4 and the outer valve core 5, a spring 7 is sheathed on the outer side of the inner guide column 4-2, and the two ends of the spring 7 respectively press against the end face of the inner valve core 4 and the head end face of the outer valve core 5. An axially extending slide groove 4-4 is provided on the inner guide column 4-2, and a radially extending fixing pin 8 is provided in the outer guide hole 5-1. The fixing pin 8 passes through the slide groove 4-4. The inner guide column 4-2 and the outer guide hole 5-1 are movably connected through the slide groove 4-4 and the fixing pin 8. When the inner guide column 4-2 is inserted into the outer guide hole 5-1 and moves axially relative to each other, the axial movement is limited by the fixing pin 8 and the slide groove 4-4 to prevent the inner valve core 4 and the outer valve core 5 from separating.

[0035] In the stop valve provided in the specific embodiment of the utility model, an annular groove 3-1 is arranged on the outer periphery of the end of the valve stem 3, an internal thread is arranged on the inner side of the internal guide hole 4-1, a matching external thread is arranged on the outer side of the internal nut 9, and a semi-open ring 10 and a gasket 11 are also arranged in the internal guide hole 4-1. The semi-open ring 10 is embedded in the annular groove 3-1, the gasket 11 supports the semi-open ring 10, and the semi-open ring 10 is pressed by the internal nut 9. The above method realizes the fixed connection between the valve stem 3 and the inner valve core 4.

[0036] In order to stably install the movable valve seat 6, a cage 12 is installed in the installation hole 1-1, the front end of the cage 12 extends out and is connected to the front end face of the valve body 1 through bolts, and the rear end of the cage 12 is inserted into the installation hole 1-1 and presses the movable valve seat 6. A sealing gasket is arranged between the cage 12 and the front end of the valve body 1, and a sealing gasket is also arranged between the rear end of the movable valve seat 6 and the valve body 1 to ensure the sealing effect of the valve.

[0037] Furthermore, a pressing sleeve 13, a pressing plate 14 and an anti-rotation clamp 15 are sequentially arranged at the head end of the cage 12, and the anti-rotation clamp 15 can make the valve stem 3 move axially but not rotate. The valve stem 3 passes through the anti-rotation clamp 15, the pressing plate 14, the pressing sleeve 13 and the cage 12 in sequence, and finally connects the inner valve core 4, and a packing 16 is arranged between the outer wall of the valve stem 3 and the inner wall of the cage 12, and the packing 16 is pressed by the pressing plate 14 and the pressing sleeve 13 to ensure the sealing effect.

[0038] On the basis of the stop valve provided in the above specific embodiments, the transmission mechanism includes a spline shaft 17 and a spline sleeve 18, the hand wheel 2 is connected to the head end of the spline shaft 17, the end of the spline shaft 17 is connected to the head end of the spline sleeve 18, and the end of the spline sleeve 18 is threadedly connected to the head end of the valve stem 3. The switching from rotational motion to linear motion is realized.

[0039] Specifically, for the stable installation of each component, the valve body 1 is provided with an axially extending support rod 19 at the head end, a middle plate 20 is installed at the head end of the support rod 19, a spline sleeve 18 passes through the middle plate 20 and is connected through the middle bearing 20-1, and is matched with components such as a gasket and a disc spring, an axially extending support rod 21 is provided at the head end of the middle plate 20, a top plate 22 is installed at the head end of the support rod 21, a spline shaft 17 passes through the top plate 22 and is connected through the top bearing 22-1. Each rod and plate are connected by bolts, and the connection method of each component can also be adjusted according to the situation, all within the protection scope of the present utility model.

[0040] The specific working method is:

[0041] When closing the valve, the hand wheel 2 is rotated clockwise to drive the spline shaft 17 and the spline sleeve 18 to rotate, and the valve stem 3 is moved to the end through the left trapezoidal thread. The third sealing surface 5-3 of the outer valve core 5 first contacts the first sealing surface 6-1 of the movable valve seat 6, and the compression spring 7 is continuously compressed to achieve the first seal. The compression spring 7 is continuously compressed, and the fourth sealing surface 4-3 of the inner valve core 4 contacts the second sealing surface 6-2 of the movable valve seat 6, and the compression is continued to achieve the second seal. The whole process achieves the purpose of double sealing, and the sealing effect is doubled.

[0042] When opening the valve, rotate the hand wheel 2 counterclockwise, the valve stem 3 moves toward the head end, driving the inner valve core 4 and the outer valve core 5 to move toward the head end. Continue to rotate the hand wheel 2, the fourth sealing surface 4-3 of the inner valve core 4 and the second sealing surface 6-2 of the movable valve seat 6 will first break away from the seal, and the first seal will be opened. At this time, because the compression spring 7 has not fully restored its elasticity, the outer valve core 5 and the movable valve seat 6 are still in a sealed state. Continue to rotate the hand wheel 2, the third sealing surface 5-3 of the outer valve core 5 will first break away from the first sealing surface 6-1 of the movable valve seat 6, and the second seal will be opened. After opening to the required position, the valve is fully opened.

[0043] The above is a detailed introduction to the stop valve provided by the utility model. This article uses specific examples to illustrate the principle and implementation method of the utility model. The description of the above embodiments is only used to help understand the method and core idea of ​​the utility model. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the utility model, the utility model can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

Claims

1. A stop valve, characterized in that: The invention comprises a valve body (1), a hand wheel (2), a transmission mechanism and a valve stem (3), wherein the valve body (1) is provided with a mounting hole (1-1), and the valve body (1) is further provided with two inlet and outlet holes (1-2) respectively connected to the mounting hole (1-1), the hand wheel (2) is connected to the head end of the valve stem (3) through the transmission mechanism, and the end of the valve stem (3) is sequentially provided with an inner valve core (4), an outer valve core (5) and a movable valve seat (6) from the inside to the outside, and the movable valve seat (6) is installed in the mounting hole (1-1), and the valve stem (3) pushes the outer valve core (5) to move the valve stem (3) toward the outside. When the valve core (5) and the inner valve core (4) move toward the rear end, the outer valve core (5) and the inner valve core (4) respectively seal and contact the first sealing surface (6-1) and the second sealing surface (6-2) of the movable valve seat (6) to isolate the two inlet and outlet holes (1-2); when the valve stem (3) pushes the inner valve core (4) and the outer valve core (5) to move toward the front end, the inner valve core (4) and the outer valve core (5) respectively leave the second sealing surface (6-2) and the first sealing surface (6-1) to connect the two inlet and outlet holes (1-2).

2. The stop valve according to claim 1, characterized in that: The mounting hole (1-1) extends along the axis, the two inlet and outlet holes (1-2) are connected to the openings of the side wall of the mounting hole (1-1) and are staggered along the axial direction, the movable valve seat (6) is located between the two openings, an axially extending stepped hole (6-3) is provided in the movable valve seat (6), the head end diameter of the stepped hole (6-3) is larger than the tail end diameter, the outer valve core (5) and the inner valve core (4) are inserted into the stepped hole (6-3), the ports of the stepped hole (6-3) are connected to the two openings respectively, the step surface in the middle of the stepped hole (6-3) is the first sealing surface (6-1), and the conical surface of the head end port of the stepped hole (6-3) is the second sealing surface (6-2).

3. The stop valve according to claim 2, characterized in that: The inner valve core (4) is provided with an inner guide hole (4-1) at the front end, and an inner guide column (4-2) is provided at the rear end of the inner valve core (4). The outer valve core (5) is provided with an outer guide hole (5-1) at the front end, and an outer guide column (5-2) is provided at the rear end of the outer valve core (5). The rear end of the valve stem (3) is fixedly mounted in the inner guide hole (4-1), the inner guide column (4-2) is inserted into the outer guide hole (5-1), and the outer guide column (5-2) is inserted into the rear end of the stepped hole (6-3), and can move relative to each other in the axial direction.

4. The stop valve according to claim 3, characterized in that: The end surface of the outer valve core (5) is a third sealing surface (5-3) in contact with the first sealing surface (6-1), and the conical surface on the outer periphery of the end of the inner valve core (4) is a fourth sealing surface (4-3) in contact with the second sealing surface (6-2).

5. The stop valve according to claim 4, characterized in that: A spring (7) is arranged between the end face of the inner valve core (4) and the head end face of the outer valve core (5); an axially extending slide groove (4-4) is arranged on the inner guide column (4-2); and a radially extending fixing pin (8) is arranged in the outer guide hole (5-1); the inner guide column (4-2) and the outer guide hole (5-1) are movably connected via the slide groove (4-4) and the fixing pin (8).

6. The stop valve according to claim 5, characterized in that: An annular groove (3-1) is provided on the outer periphery of the end of the valve stem (3), and a semi-open ring (10) is pressed against the inner side of the inner guide hole (4-1) via an inner nut (9), and the semi-open ring (10) is embedded in the annular groove (3-1).

7. The stop valve according to claim 1, characterized in that: A cage sleeve (12) is installed in the installation hole (1-1); the front end of the cage sleeve (12) is connected to the valve body (1) via bolts, and the rear end of the cage sleeve (12) presses the movable valve seat (6).

8. The stop valve according to claim 7, characterized in that: The front end of the cage sleeve (12) is provided with a pressing sleeve (13), a pressing plate (14) and an anti-rotation clamp (15) in sequence.

9. The stop valve according to any one of claims 1 to 8, characterized in that: The transmission mechanism comprises a spline shaft (17) and a spline sleeve (18), the hand wheel (2) is connected to the head end of the spline shaft (17), the end of the spline shaft (17) is connected to the head end of the spline sleeve (18), and the end of the spline sleeve (18) is threadedly connected to the head end of the valve stem (3).

10. The stop valve according to claim 9, characterized in that: The valve body (1) is provided with an axially extending support rod (19) at the head end, a middle plate (20) is installed at the head end of the support rod (19), the spline sleeve (18) passes through the middle plate (20) and is connected via a middle bearing (20-1), the middle plate (20) is provided with an axially extending support rod (21) at the head end, a top plate (22) is installed at the head end of the support rod (21), the spline shaft (17) passes through the top plate (22) and is connected via a top bearing (22-1).

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