JP2008274779A - Intake-exhaust valve and valve mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake-exhaust valve capable of minimizing a variation in a diameter of a shaft part by the temperature, by enabling effective cooling. <P>SOLUTION: This intake-exhaust valve has an intake-exhaust valve body 46 having the shaft part 46a and a shade part 46b, forming an inside space 45 inside the shaft part 46a and the shade part 46b and sealing a heat conduction medium (such as sodium) in the inside space 45, and an orifice member 54 arranged in a state of partitioning the inside of the inside space 45 into a lower side space and an upper side space and having an orifice hole 54a limiting the movement of the heat conduction medium between both spaces. A diameter of the orifice hole 54a changes in response to the temperature of the intake-exhaust valve body 46. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an intake / exhaust valve and a valve mechanism, and more particularly to an intake / exhaust valve having a hollow portion in which a heat conduction medium is enclosed and a valve mechanism including the intake / exhaust valve.

  Generally, a cylinder head of an internal combustion engine is formed with a combustion chamber, an intake port for supplying gas to the combustion chamber, an exhaust port for discharging gas in the combustion chamber, and the like. Is opened and closed by each of an intake valve and an exhaust valve (hereinafter collectively referred to as “intake and exhaust valves”). The intake / exhaust valve has a shaft portion (stem portion) and an umbrella portion provided at one end portion of the stem portion, and the umbrella portion faces the combustion chamber. For this reason, when fuel burns in the combustion chamber, the heat generated at that time is easily transmitted to the umbrella portion of the intake / exhaust valve. If the temperature of the valve umbrella rises excessively under the influence of this heat, for example, the combustion state deteriorates, and abnormal combustion such as knocking and pre-ignition is induced, which may result in a decrease in thermal efficiency and a decrease in output. is there. In particular, recent internal combustion engines have improved output compared to conventional internal combustion engines, and accordingly, the amount of heat generated has also increased.

  Therefore, in recent years, in order to avoid the influence of the heat, a valve guide and an oil seal that are arranged in contact with or in proximity to a valve seat that contacts the umbrella part, or an intake / exhaust valve, the heat transmitted to the umbrella part. The technique of radiating heat to the cooling water existing in the cylinder head is employed. Recently, a hollow part that encloses the cooling medium is formed inside the valve, and the cooling medium is splattered in the hollow part by the opening and closing operation of the valve, facilitating the transfer of heat from the umbrella part side to the stem part side. Techniques for making them have also been proposed. Furthermore, a technique for efficiently cooling the hollow valve (for example, see Patent Documents 1 and 2, etc.), a technique for suppressing thermal deterioration of the oil seal (for example, see Patent Document 3), and the like are also disclosed. .

JP 2006-097498 A JP-A-8-210112 JP 2006-249996 A

  However, the techniques described in Patent Document 1 and Patent Document 2 can achieve efficient cooling of the valve, but are performed when the temperature of the valve is low (for example, when the internal combustion engine is warming up). However, since the same cooling as when the temperature is high is performed, the valve may be in an overcooled state. In this supercooled state, the valve contracts excessively, so that the clearance between the valve and the valve guide is widened. As a result, the movement range in the direction intersecting the sliding direction of the valve is increased. In such a case, when the valve and the valve guide come into contact with each other, there is a high possibility that the wear of the valve guide will increase.

  Further, in the supercooled state, the clearance between the valve and the oil seal is also widened. Therefore, when the valve and the oil seal are in contact with each other in this state, the wear of the oil seal may be increased as described above. Further, since the clearance between the valve and the oil seal is widened, there is a possibility that the oil drop will increase and the oil consumption will increase.

  In addition, the technique described in Patent Document 3 suppresses thermal deterioration of the oil seal by using a heat insulating portion as a part where the oil seal contacts. However, the change in clearance between the valve and the oil seal Even the oil seal wear due to contact is not considered.

  Therefore, the present invention has been made in view of the above-described problems, and an object thereof is to provide an intake / exhaust valve capable of effective cooling and capable of suppressing the variation of the diameter of the shaft portion due to temperature as much as possible. To do. It is another object of the present invention to provide a valve mechanism that can be used for a long time without being affected by wear or the like as much as possible.

  In order to solve the above-described problems, an intake / exhaust valve according to the present invention includes a shaft portion and an umbrella portion provided at one end of the shaft portion, and a hollow portion is formed inside the shaft portion and the umbrella portion. An intake / exhaust valve main body in which a heat transfer medium is enclosed in the hollow portion, and a state in which the inside of the hollow portion is partitioned into the space on the one end side and the space on the other end side, and the space on the one end side, A throttle member having a throttle hole that restricts movement of the heat transfer medium between the other end side space, and the diameter of the throttle hole changes according to the temperature of the intake and exhaust valve body Features.

  According to this, since the diameter of the throttle hole changes according to the temperature of the intake / exhaust valve main body, when the temperature of the intake / exhaust valve main body is high, the diameter of the throttle hole is increased so that the one end side space and the other The intake / exhaust valve main body is effectively cooled by promoting the movement of the heat transfer medium between the end-side spaces. In addition, when the temperature of the intake / exhaust valve body is low, the diameter of the throttle hole is reduced to restrict the movement of the heat transfer medium between the space on one end side and the space on the other end side, thereby Suppresses overcooling as much as possible. As a result, effective cooling according to the temperature of the intake / exhaust valve main body is possible, and therefore, variation in the diameter of the shaft portion due to temperature can be suppressed as much as possible.

  In this case, the diameter of the throttle hole may be changed according to a change in the diameter of the shaft portion due to a temperature change of the intake / exhaust valve main body.

  The diaphragm member may be made of an elastic contraction body. In this case, the diaphragm member may be a substantially cylindrical member having a substantially C-shaped cross section.

  The valve mechanism according to the present invention includes the intake / exhaust valve according to the present invention, and a valve guide that supports the intake / exhaust valve slidably on the shaft portion.

  According to this, since the intake / exhaust valve that can suppress the variation of the shaft diameter due to the temperature of the intake / exhaust valve body as much as possible is provided, the variation in the clearance between the intake / exhaust valve and the valve guide is also minimized. It becomes possible to suppress. As a result, it can be used for a long time without being affected by wear and the like as much as possible.

  In this case, the position of the throttle member in the hollow portion may be a position where the throttle member is always located on the one end side with respect to the valve guide while the intake / exhaust valve slides. The entire portion of the valve guide that faces the shaft portion may face at least a part of the throttle member via the shaft portion while the intake / exhaust valve slides.

  Further, in the present invention, the positional relationship with respect to the valve guide is fixed, the insertion portion has an insertion hole into which the shaft portion of the intake / exhaust valve is inserted, and according to the clearance between the shaft portion and the insertion hole. Further, a seal member that restricts movement of fluid from the other end side of the shaft portion to the one end side may be further provided.

  According to the present invention, it is possible to provide an intake / exhaust valve capable of effective cooling and capable of suppressing fluctuations in the diameter of the shaft portion due to temperature as much as possible. Further, according to the present invention, it is possible to provide a valve mechanism that can be used over a long period of time without being affected by wear or the like as much as possible.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. 1 to 5C.

  FIG. 1 shows a partial configuration diagram of a cylinder head 12 in an internal combustion engine. As shown in FIG. 1, a combustion chamber 22 and an intake port 24 for introducing intake air into the combustion chamber 22 are formed in the cylinder head 12 so as to communicate with the combustion chamber 22. ing. Further, the cylinder head 12 is provided with an intake valve mechanism 30 for bringing the intake port 24 and the combustion chamber 22 into communication or non-communication. Although not shown in the figure, the cylinder head 12 is in communication with the combustion chamber 22 and is also provided with an exhaust port for exhausting the gas burned in the combustion chamber 22. The head 12 is provided with an exhaust valve mechanism for bringing the exhaust port and the combustion chamber 22 into communication or non-communication.

  The intake valve mechanism 30 is a direct-acting valve mechanism, and includes an intake valve 32 that can reciprocate vertically in FIG. 1, a valve guide 34 that supports the intake valve 32 in a reciprocable state, and a valve guide. 34, an oil seal 36 fixed to 34, a valve spring 38 made of a compression coil spring in which the intake valve 32 is inserted, and a cam that contacts the upper end of the intake valve 32 and rotates about the rotation axis of the cam shaft 42 44. Among these, the lower end portions of the valve guide 34, the oil seal 36, and the valve spring 38 are fixed to the cylinder head 12 side. A valve seat 58 is provided at the end of the intake port 24 on the combustion chamber 22 side. The lower end side of the valve seat 58 is always in contact with the intake valve 32 when the intake valve 32 is in the state shown in FIG.

  As shown in FIG. 2, the intake valve 32 includes a valve body 46 having a shaft portion 46a having a cylindrical shape and a funnel-shaped umbrella portion 46b provided at a lower end portion of the shaft portion 46a, and a shaft portion. The upper cap part 48 which closes the opening of the upper end part of 46a, the lower cap part 52 which obstruct | occludes the opening of the lower end part of the umbrella part 46b, and these valve bodies 46, the upper cap part 48, and the lower cap part 52 are comprised. And a diaphragm member 54 provided in a state of partitioning the interior space (hollow part) 45. The valve body 46 is made of, for example, heat resistant steel (silchrome steel (SUH3)). Further, the valve main body 46 and each of the upper cap portion 48 and the lower cap portion 52 are joined by a joining technique such as laser welding or brazing. Further, sodium (Na) as a heat conduction medium is sealed in the internal space 45 (see FIG. 1). This sodium is in a liquid state at least during operation of the internal combustion engine, and its volume is, for example, about 50 to 70% of the volume of the internal space 45.

  Note that the heat conduction medium is not limited to sodium, and other metals (potassium (K) or the like) that are melted by heat to become a liquid may be employed. Moreover, it is good also as employ | adopting the ceramics and metal fine powder which do not fuse | melt with heat, such as aluminum nitride (AlN).

  The throttle member 54 is made of, for example, an elastic contraction member (for example, spring steel), and has a substantially C-shaped cross section as can be understood from FIG. 3 which is a cross-sectional view taken along line AA in FIGS. It is comprised from the substantially cylindrical member which has. That is, the throttle member 54 is formed with a throttle hole 54a and a notch 54b along the longitudinal direction. The throttle member 54 is fixed in a state of being press-fitted into the shaft portion 46 a of the valve body 46. The throttle member 54 is fixed at the uppermost position shown in FIG. 4A showing the state where the intake valve 32 is located at the lowest position with respect to the valve guide 34 when the intake valve 32 slides. As shown in FIG. 4B, the upper end portion of the throttle member 54 is always positioned below the lower end portion of the valve guide 34 while the intake valve 32 slides relative to the valve guide 34. ing. The throttle member 54 limits the movement of sodium between the space above and below the space according to the size of the diameter of the throttle hole 54a.

  Returning to FIG. 1, the valve guide 34 is a substantially cylindrical member made of a material (for example, aluminum) having a higher thermal conductivity than the intake valve 32, and is inserted into a guide hole 34 a formed along the axis thereof. On the other hand, the intake valve 32 (shaft portion 46a) is inserted. A predetermined clearance is formed between the inner peripheral surface of the valve guide 34 and the outer peripheral surface of the shaft portion 46a, and the valve guide 34 restricts movement of the intake valve 32 in a direction other than the axial direction (longitudinal direction). Has been. In the present embodiment, it is assumed that the relationship between the diameter of the guide hole 34a and the diameter of the shaft portion 46a is set so that this clearance is optimal at the end of warm-up of the internal combustion engine.

  The oil seal 36 is a member for preventing oil that lubricates the cylinder head 12 from flowing through the intake valve 32 and flowing into the combustion chamber 22, and has an upper portion having substantially the same diameter as the shaft portion 46a. A hole 36a is formed. A minute clearance is formed between the hole 36a of the oil seal 36 and the intake valve 32 (shaft portion 46a), and a small amount of oil is supplied to the clearance, whereby the oil seal It is possible to slide the intake valve 32 with respect to 36 for lubrication.

  The valve spring 38 is provided in a state in which an upper seat 64 provided near the upper end of the intake valve 32 (shaft portion 46a) via a valve cotter 62 and a lower seat 66 provided on a part of the cylinder head 12 are connected. Thus, an upward biasing force is always applied to the intake valve 32.

  The cam 44 is rotationally driven via the cam shaft 42 by a rotation drive mechanism (not shown). The rotation of the cam 44 applies a force (downward force) against the urging force of the valve spring 38 to the upper end portion (upper cap portion 48) of the intake valve 32, and the downward force generated by the cam 44 and the valve The intake valve 32 moves up and down due to the balance with the upward force by the spring 38. In the present embodiment, since the center of the central axis AX (upper and lower direction in the drawing) of the intake valve 32 and the center of the cam width (width in the direction perpendicular to the drawing) are offset with respect to the direction orthogonal to the drawing, It moves up and down while rotating around the central axis AX. Accordingly, the position of the umbrella portion 46b of the intake valve 32 that contacts the valve seat 58 is changed according to the rotation of the cam.

  In the intake valve mechanism 30 configured as described above, the intake valve 32 is in the state shown in FIG. 1 (the state that is the same as the state shown in FIG. 4B and is located on the uppermost side with respect to the valve guide 34). In addition, the intake port 24 and the combustion chamber 22 are set in a non-communication state (closed state). Further, as the cam 44 rotates, the intake valve 32 moves downward from the state of FIG. 1, so that the communication state (open state) is set between the intake port 24 and the combustion chamber 22. In the present embodiment, the intake valve 32 is reciprocated up and down (and rotated around the axis) so that the closed state and the open state are switched at a constant cycle. The internal sodium is agitated (shaking). In this case, sodium moves between the upper space and the lower space of the throttle member 54 via the throttle hole 54a. Therefore, when the heat generated in the combustion chamber 22 is conducted to the lower end surface (the lower surface of the lower cap portion 52) of the intake valve 32 facing the combustion chamber 22, the temperature of sodium is caused by the heat of the lower cap portion 52. However, the sodium moves while transferring heat to the shaft portion 46a during the stirring (shaking). Since the valve guide 34 made of a material having a higher thermal conductivity than the shaft portion 46a is close to the shaft portion 46a whose temperature is increased in this way, the heat of the shaft portion 46a is transmitted to the valve guide 34, The heat of the shaft portion 46a is radiated to the valve guide 34 (hereinafter, this operation is referred to as “cooling operation”).

  Next, the effect | action of the aperture member 54 provided in the internal space 45 is demonstrated based on Fig.5 (a)-FIG.5 (c). FIG. 5A shows the throttle hole 54a when the temperature of the shaft portion 46a is at a predetermined reference temperature (here, for example, the temperature at the time when the warm-up operation of the internal combustion engine is finished). The relationship between the diameter and the clearance between the shaft portion 46a and the valve guide 34 is schematically shown. FIG. 5B shows the relationship when the shaft portion 46a is hotter than the state of FIG. 5A, and FIG. 5C shows the state of FIG. The relationship when the shaft portion 46a is at a low temperature is shown.

Among these, in the state of FIG. 5B (the temperature of the shaft portion 46a is higher than the reference temperature), the shaft portion 46a expands in the radial direction due to thermal expansion, as can be seen from FIG. 5A. To do. Along with this expansion, the throttle member 54 press-fitted into the shaft portion 46a also tends to spread outward due to the elastic force, so that the diameter of the throttle hole 54a also increases (R ₁ → R ₂ ). Thereby, since the movement of sodium through the throttle hole 54a is promoted, the cooling operation is promoted in the state of FIG. 5B than in the state of FIG.

On the other hand, in the state of FIG. 5C (the state where the temperature of the shaft portion 46a is lower than the reference temperature), the shaft portion 46a contracts in the radial direction as can be seen from the comparison with FIG. With this contraction, the diameter of the throttle hole 54a is also reduced (R ₁ → R ₃ ) because the throttle member 54 press-fitted into the shaft portion 46a tends to narrow inward. As a result, the movement of sodium through the throttle hole 54a is suppressed. Therefore, in the state of FIG. 5C, the cooling operation is suppressed, and the shaft portion 46a (more specifically, from the throttle member 54 of the shaft portion 46a). Also, the supercooling of the upper part) is suppressed.

  That is, in the present embodiment, by providing the throttle member 54 in the internal space 45, the diameter of the throttle hole 54a can be changed without special control, thereby performing an appropriate cooling operation according to the temperature. It is possible to realize.

For this reason, for example, even when the temperature of the valve body 46 is low (see FIG. 5C), such as when the internal combustion engine is warming up, the shaft portion 46a is not supercooled. The clearance (C ₃ ) between the outer peripheral surface of the valve guide 34 and the inner peripheral surface of the valve guide 34 does not become extremely large compared to the clearance (C ₁ ) at the reference temperature, and the axial direction of the valve main body 46 (in the paper surface) The movement range in the direction intersecting the (vertical direction) can be kept small. Thereby, the wear when the valve main body 46 and the valve guide 34 come into contact with each other can be kept small.

Further, even when the temperature of the valve body 46 is high (see FIG. 5B), for example, when the internal combustion engine is performing a normal operation, an effective cooling operation of the shaft portion 46a is performed. Therefore, the clearance (C ₂ ) between the outer peripheral surface of the shaft portion 46a and the inner peripheral surface of the valve guide 34 does not become extremely small compared to the clearance (C ₁ ) at the reference temperature.

  In the above description, the clearance between the valve main body 46 (shaft portion 46a) and the valve guide 34 (guide hole 34a) has been described. However, the clearance between the valve main body 46 (shaft portion 46a) and the oil seal 36 (hole portion 36a). The clearance between them is the same as described above. That is, the clearance between the shaft portion 46a and the oil seal 36 (hole portion 36a) can also be maintained within a predetermined range of clearance (a constant range of clearance including the clearance after completion of the warm-up operation). Can be suppressed as much as possible. In this case, it is also possible to suppress as much as possible the oil drop caused by the decrease in the tightening force between the oil seal 36 and the shaft portion 46a.

  As described above in detail, according to the intake valve 32 of the present embodiment, when the temperature of the valve body 46 is high, the diameter of the throttle hole 54a increases, and the upper space and the lower space of the throttle member 54 Since the movement of the heat conduction medium (sodium) between the two is promoted, the valve body 46 can be cooled effectively. Further, when the temperature of the valve body 46 is low, the diameter of the throttle hole 54a is reduced, and movement of the heat conduction medium (sodium) between the upper space and the lower space is suppressed. Supercooling is effectively suppressed. Accordingly, appropriate cooling according to the temperature of the valve main body 46 can be performed without performing special control or the like, so that the diameter of the shaft portion 46a of the valve main body 46 falls within a predetermined range (for example, the end of the warm-up operation). A certain range of diameters including the later diameter). In addition, since the combustion state is improved by cooling the valve body 46, abnormal combustion such as knocking or pre-ignition can be suppressed, and as a result, thermal efficiency and output can be improved.

  Further, according to the intake valve mechanism 30 of the present embodiment, since the intake valve 32 in which the temperature of the valve main body 46 and the diameter of the shaft portion 46a are maintained within a predetermined range is provided, the connection between the shaft portion 46a and the valve guide 34 is provided. The clearance between the shaft portion 46a and the oil seal 36 can be maintained within an appropriate range. Thereby, since wear of the valve guide 34 and the oil seal 36 can be suppressed, these members can have a long life. In addition, since the clearance between the shaft portion 46a and the oil seal 36 is maintained within an appropriate range, it is possible to suppress oil drop and reduce oil consumption.

  Further, according to the intake valve mechanism 30 of the present embodiment, the position of the throttle member 54 in the internal space 45 is a position where the throttle member 54 is always positioned below the valve guide 34 while the intake valve 32 slides. Therefore, the clearance between the shaft portion 46a and the valve guide 34 can be maintained substantially uniformly throughout the entire area.

  In the above embodiment, the case where the intake / exhaust valve of the present invention is applied to the intake valve 32 and the valve mechanism of the present invention is applied to the intake valve mechanism 30 has been described, but the present invention is not limited to this. The intake / exhaust valve of the present invention may be applied to an exhaust valve (not shown), and the valve mechanism of the present invention may be applied to an exhaust valve mechanism (not shown). In addition, as a material of the valve main body which comprises an exhaust valve mechanism, 21-4N steel (SUH35) is mentioned, for example.

  In the above-described embodiment, the valve body 46 is positioned at the lowest position with respect to the valve guide 34 (FIG. 4A), and the valve body 46 is positioned at the highest position with respect to the valve guide 34 (FIG. 4). 4 (b)), the description has been given of the case where the upper end portion of the throttle member 54 is fixed in the valve main body 46 so as not to be positioned above the lower end portion of the valve guide 34. However, the present invention is not limited to this, and for example, a diaphragm member 54 ′ as shown in FIGS. 6A and 6B may be employed. In this case, when the valve body 46 is positioned at the lowest position with respect to the valve guide 34 (FIG. 6A), and when the valve body 46 is positioned at the highest position with respect to the valve guide 34 (FIG. 6B). In any case, the entire inner peripheral surface of the valve guide 34 and at least a part of the outer peripheral surface of the throttle member 54 'are always opposed to each other via the shaft portion 46a. Even when such a throttle member 54 ′ is employed, the clearance between the shaft portion 46 a and the valve guide 34 can be uniformly maintained over the entire area, as in the above embodiment.

  In the above embodiment, the case where the throttle member 54 has a substantially C-shaped cross section has been described. However, the present invention is not limited to this, and the diameter of the throttle hole is changed according to the temperature of the shaft portion 46a. The shape is not limited as long as it can be used. Moreover, although the said embodiment demonstrated the case where the aperture | diaphragm | squeeze member 54 was substantially cylindrical shape, you may have not only this but a substantially ring shape.

  Moreover, although the case where only one throttle member 54 is provided in the internal space 45 has been described in the above embodiment, the present invention is not limited to this, and two or more throttle members 54 may be provided.

  Moreover, although the said embodiment demonstrated the case where the aperture hole 54a of the aperture | diaphragm | squeeze member 54 changed with the change of the diameter of the axial part 46a, it is not restricted to this, The aperture hole 54a according to a temperature change. It is also possible to provide a mechanism for actively changing the diameter. In short, any configuration may be used as long as the diameter of the throttle hole changes according to the temperature change of the shaft portion 46a.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

It is a partial block diagram of a cylinder head of an internal combustion engine including an intake valve mechanism. It is a figure which takes out and shows an intake valve. It is the sectional view on the AA line of FIG. It is a figure which shows the relative movement range of an intake valve and a valve guide. It is a figure which shows typically the relationship between the diameter of an aperture hole, and the clearance between a shaft part and a valve guide. It is a figure which shows the modification of an intake valve.

Explanation of symbols

Reference Signs List 30 Intake valve mechanism 32 Intake valve 34 Valve guide 36 Oil seal 45 Internal space 46 Valve body 46a Shaft portion 46b Umbrella portion 54 Throttle member 54a Throttle hole

Claims (8)

An intake / exhaust valve having a shaft portion and an umbrella portion provided at one end of the shaft portion, a hollow portion is formed in the shaft portion and the umbrella portion, and a heat conduction medium is enclosed in the hollow portion The body,
A throttle that is provided in a state of partitioning the inside of the hollow portion into a space on the one end side and a space on the other end side, and restricts movement of the heat transfer medium between the space on the one end side and the space on the other end side. A throttle member having a hole,
An intake / exhaust valve according to claim 1, wherein the diameter of the throttle hole changes according to the temperature of the intake / exhaust valve body. 2. The intake / exhaust valve according to claim 1, wherein the diameter of the throttle hole changes according to a change in the diameter of the shaft portion due to a temperature change of the intake / exhaust valve main body. The intake / exhaust valve according to claim 1, wherein the throttle member is made of an elastic contraction body. The intake / exhaust valve according to claim 3, wherein the throttle member is a substantially cylindrical member having a substantially C-shaped cross section. The intake / exhaust valve according to any one of claims 1 to 4,
And a valve guide that slidably supports the intake / exhaust valve on the shaft portion. 6. The position of the throttle member in the hollow portion is a position where the throttle member is always located on the one end side with respect to the valve guide while the intake / exhaust valve slides. Valve mechanism. The whole portion of the valve guide that faces the shaft portion is opposed to at least a part of the throttle member via the shaft portion while the intake / exhaust valve slides. Valve mechanism. The positional relationship with respect to the valve guide is fixed, and has an insertion hole into which the shaft portion of the intake / exhaust valve is inserted, and according to the clearance between the shaft portion and the insertion hole, the shaft portion The valve mechanism according to claim 5, further comprising a seal member that restricts movement of fluid from the other end side to the one end side.

Images