Title of Invention

REED VALVE

Abstract

"REED VALVE" A reed valve which comprises a valve seat member (20) comprising a valve seat (22) and a valve hole (21) opening at said valve seat (22), and a reed (24) having a base end attached to said valve seat member (20) and having a free end extending in the longitudinal direction while covering said valve hole (21) so as to open and close said valve hole (21) in cooperation with said valve seat (22), wherein a projection (27) for inhibiting said reed (24) from entering into said valve hole (21) is provided on the inside surface along the longitudinal direction of said reed (24), of said valve hole (21). Fig. 1

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] COMPLETE SPECIFICATION [See Section 10] "REED VALVE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan The following specification particularly describes the nature of the invention and the manner in which it is to be performed :- comprising a valve seat and a valve hole opening at the valve seat, and a reed having a base end attached to the valve seat member and having a free end extending in the longitudinal direction while covering the valve hole so as to open and close the valve hole in cooperation with said valve seat. [0002] [Prior Art] Such a reed valve as this has been already known, as disclosed, for example, in Japanese Patent Publication No. Sho 60-32339. [0003] [Problems to be Solved by the Invention] Such a reed valve as above, generally, is widely used for transporting a gas in one direction by opening and closing a valve hole through flexural vibration of a reed by pressure pulsation in the surroundings. Depending on the flow conditions of the gas in the surroundings of the reed, the reed may undergo a distortional deformation about the longitudinal axis thereof and may enter into the valve hole. [0004] In order to prevent such a situation, conventionally, it has been practiced to sufficiently enlarge the lap margin of the reed in relation to the valve seat. Setting the lap margin of the reed in relation to the valve seat to be larger than the size required for shutting off the valve hole leads to a reduction of response characteristics of the reed to the pressure pulsation through an increase in the spring constant of the reed, or leads to a reduction in the opening area of the valve hole, and, in either case, causes the inconvenience that the flow rate of the gas transported is reduced. Accordingly, in order to compensate for the reduction in the flow rate of the gas transported, it has been necessary to enlarge the reed valve itself in size. [0005] The present invention has been made in consideration of the above-mentioned circumstances. Accordingly, it is an object of the present invention to provide the above-mentioned reed valve by which it is possible to enhance the response characteristics of the reed to pressure pulsation, by setting the lap margin of the reed in relation to the valve seat at the required minimum limit value for shutting off the valve hole, and it is possible to prevent the reed from entering into the valve hole, while securing a predetermined opening area of the valve hole. [0006] [Means for Solving the Problems] In order to attain the above object, the present invention is firstly characterized in that, in a reed valve which comprises a valve seat member comprising a valve seat and a valve hole opening at the valve seat, and a reed having a base end attached to the valve seat member and having a free end extending in the longitudinal direction while covering the valve hole so as to open and close the valve hole in cooperation with the valve seat, a projection for inhibiting the reed from entering into the valve hole is provided on the inside surface along the longitudinal direction of the reed, of the valve hole. [0007] According to the first characteristic feature, even when the reed tends to enter into the valve hole while being twisted around the longitudinal axis thereof due to the flow conditions of a gas in the surroundings of the reed, the projection on the inside surface of the reed receives a major side edge portion of the reed and restrain the twisting of the reed, whereby the reed can be inhibited from entering into the valve hole. As a result, the lap margin of the reed in relation to the valve seat can be set at the required minimum limit value for shutting off the valve hole, an increase in the spring constant of the reed can be obviated, the response characteristics of the reed to pressure pulsation can be enhanced, and the reed valve can be made smaller in size while securing a desired flow rate of the gas. [0008] In addition, the present invention is secondly characterized in that, in a reed valve which comprises a valve seat member comprising a valve seat and a valve hole opening at the valve seat, and a reed having a base end attached to the valve seat member and having a free end extending in the longitudinal direction while covering the valve hole so as to open and close the valve hole in cooperation with the valve seat, a projection for inhibiting the reed from entering into the valve hole is provided at a side edge along the longitudinal direction of the reed. [0009] According to the second characteristic feature, even when the reed tends to enter into the valve hole while being twisted around the longitudinal axis thereof due to the flow conditions of a gas in the surroundings of the reed, the projection on the side edge of the reed is received by the valve seat, whereby twisting of the reed is restrained, and the reed can be inhibited from entering into the valve hole. As a result, the lap margin of the reed in relation to the valve seat can be set at the required minimum limit value for shutting off the valve hole, an increase in the spring constant of the reed can be obviated, and the response characteristics of the reed to pressure pulsation can be enhanced. In addition, the presence of the projection does not particularly reduce the opening area of the valve hole, and a reduction in the size of the reed valve can be contrived while securing a desired flow rate of the gas. [0010] Further, the present invention is thirdly characterized in that, in addition to the first or second characteristic feature, the valve hole is formed in a roughly rectangular shape whose longitudinal direction is the same as that of the reed, and the distance from an end edge of the valve hole on the side of the base end of the reed to the projection is set at about 75% of the major side length of the valve hole. [0011] According to the third characteristic feature, the effect of the projection for restraining the twisting of the reed becomes conspicuous, and the twisting of the reed can be effectively prevented while setting the projection length of the projection to be as small as possible. [0012] Furthermore, the present invention is fourthly characterized in that, in addition to any of the first to third characteristic features, the reed valve is intermediately disposed in a secondary air passage connected to an exhaust system of an internal combustion engine, with the reed directed toward the downstream side of the passage. [0013] Incidentally, the exhaust system corresponds to an exhaust port 6 in an embodiment of the present invention which will be described later. [0014] According to the fourth characteristic feature, the reed always vibrates in appropriate response to the pressure pulsation in the exhaust system, and secondary air can be securely supplied to the exhaust system, thereby contributing to clarification of exhaust gas. [0015] [Mode for Carrying Out the Invention] A mode for carrying out the present invention will be described based on one embodiment of the present invention shown in the accompanying drawings... [Brief Description of the Drawings] [Fig. 1] A vertical sectional view of an internal combustion engine fitted with a reed valve according to a first embodiment of the present invention. [Fig. 2] An enlarged vertical sectional view of the reed valve.. [Fig. 3] A partially broken front view of the reed valve (a view taken along arrow 3 of Fig. 2). [Fig. 4] A back view of the reed valve (a view taken along arrow 4 of Fig. 2). •rFig. 5] - A partially broken front view of a reed valve according to a second embodiment of the present invention. [Fig. 6] A back view of the reed valve. [0016] Fig. 1 is a vertical sectional view of an internal combustion engine fitted with a reed valve according to a first embodiment of the present invention; Fig. 2 is an enlarged vertical sectional view of the reed valve; Fig. 3 is a partially broken front view of the reed valve (a view taken along arrow 3 of Fig. 2); Fig. 4 is a back view of the reed valve (a view taken along arrow 4 of Fig. 2); Fig. 5 is a partially broken front view of a reed valve according to a second embodiment of the present invention; and Fig. 6 is a back view of the reed valve. [0017] ■ First, description will be started with a description of the first embodiment of the present invention shown in Figs. 1 to 4. [0018] In Fig. 1, reference symbol E denotes an internal combustion engine for a motorcycle. The internal combustion engine E comprises a cylinder block 1, a cylinder head 2 and a head cover 3 which are sequentially jointed from the lower side. The cylinder head 2 is provided with a combustion chamber 4, and an intake port 5 and an exhaust port 6 opened into the combustion chamber 4, and is provided with an intake valve 7 and an exhaust valve 8 for opening and closing the intake and exhaust ports 5, 6, and a valve operating mechanism 9 for driving the intake and exhaust valves 7, 8 to open and close. The valve operating mechanism 9 is disposed in a valve operating chamber 10 defined between the cylinder head 2 and the head cover 3. A carburetor (not shown) is fitted to the upstream side of the intake port 5, and a muffler (not shown) is connected to the downstream side of the exhaust port 6 through an exhaust pipe. [0019] In addition, the head cover 3 is provided with a valve housing 11 for fitting a reed valve V according to the present invention. The valve housing 11 is comprised of a lower housing half lib formed as one body with the head cover 3, and an upper housing half 11a screwed to an upper surface of the head cover 3. The reed valve V is fitted to the upper housing half 11a, and a lower surface thereof is pressed by the lower housing half lib. The reed valve V permits a flow of a gas only in one direction from the side of the upper housing half 11a to the side of the lower housing half lib. [0020] An air cleaner 14 is connected to the upper housing half 11a through a secondary upstream passage 12a, and a control valve 15 opened upon detection of an intake negative pressure equal to or higher than a prescribed value is disposed at an intermediate portion of the secondary upstream passage 12a. The lower housing half lib is connected to the exhaust port 6 through a secondary downstream passage 12b. The secondary upstream and downstream passages 12a and 12b constitute a secondary air passage 12 for guiding air filtered by the air cleaner 14 to the exhaust port 6, and, therefore, the reed valve V and the control valve 15 are disposed in series at intermediate portions of the secondary air passage 12. [0021] Now, the constitution of the reed valve V will be described referring to Figs. 2 to 4. [0022] The reed valve V comprises a valve seat member 20, a reed 24 and a stopper plate 25 as components thereof. [0023] The valve seat member 2 0 is roughly rectangular in shape and plate-like in form, and is provided with a valve hole 21 piercing through both side surfaces of the valve seat member 20, at a position away from a reed fitting portion 20a at one end portion in the longitudinal direction thereof. The valve hole 21 also is formed in a roughly rectangular shape whose longitudinal direction is the same as that of the valve seat member 20, and a valve seat 22 made of an elastic material such as rubber and surrounding the periphery of the valve hole 21 is fitted to one side surface of the valve seat member 20. In addition, a seal member 23 made of an elastic material such as rubber is fitted onto the periphery of the valve seat member 20. [0024] The reed 24 is constituted of an extremely thin elastic metallic sheet, and is so disposed as to be seated on the valve seat 22 while covering the valve hole 21. The reed 24 also is formed in a roughly rectangular shape whose longitudinal direction is the same as that of the valve seat member 20, one end portion in the longitudinal direction (base end portion) thereof is attached to the reed fitting portion 20a of the valve seat member 20 together with one end portion of the stopper plate 25 by a pair of small screws 26, 26, and the other end thereof is made to be a free end. A lap margin S of the reed 24 in relation to the valve seat 22 is set at the minimum limit value required for shutting off the valve hole 21. Besides, a pair of projection 27, 27 are provided on both inside surfaces on the side of the major sides of the valve hole 21, in order to inhibit the reed 24 from entering into the valve hole 21. In this case, the projections 27, 27 are so arranged that the following formula is established. [0025] Where the major side length of the valve hole 21 is L, the distance L' from the end edge of the valve hole 21 on the side of the base end of the reed 24 to the above-mentioned projection 27 is set as: L' ^ 0.75L Namely, the projections 27, 27 are disposed at locations of about 75% of the major side length L of the valve hole 21, as measured from the end edge of the valve hole 21 on the side of the base end of the reed 24. [0026] The stopper plate 25 is for restricting the maximum flexure of the reed 24 by receiving the back side of the reed 24 at the time of valve opening when the reed 24 parts away from the valve seat 22, and is so bent as to part away from the reed 24 in the direction from its one end portion attached to the reed fitting portion 20a of the valve seat member 2 0 toward its other end. [0027] The reed valve V constituted as above has the valve seat member 20 fitted to the upper housing half 11a, with the reed 24 and the stopper plate 25 directed toward the lower housing half lib, as shown in Fig. 1. In this case, the seal member 23 makes close contact with the inside circumferential surface of the upper housing half 11a, to keep the air-tightness of the fitting portion between the valve seat member 20 and the upper housing half 11a. [0028] Next, actions of the first embodiment will be described. [0029] At the time of deceleration operation of the internal combustion engine E, when the intake negative pressure reaches or exceeds a predetermined value, the control valve 15 detecting this condition opens, to set the secondary upstream passage 12a into a communicating condition. Then, when pressure pulsation is generated in the exhaust system including the exhaust port 6 and the exhaust pipe connected thereto, the pulsation is transmitted through the secondary downstream passage 12b to reach the interior of the lower housing half lib, thereby vibrating the reed 24 of the reed valve V in the opening and closing directions. Namely, when the negative pressure comes to the interior of the lower housing half lib, the reed 24 parts away from the valve seat 22 to open the valve hole 21, so that the negative pressure is transmitted to the secondary upstream passage 12a; as a result, the outside air having been filtered by the air cleaner 14 is sucked through the secondary air passage 12 and the valve hole 21 into the exhaust port 6. On the other hand, when a positive pressure comes to the interior of the lower housing half lib, the reed 24 is seated on the valve seat 22 to close the valve hole 21, so that backflow of air in the secondary air passage 12 is inhibited. By the pressure pulsation in the exhaust system and the operation of the reed valve V as just described, secondary air is intermittently introduced to the exhaust port 6 through the secondary air passage 12, so the even in the presence of an increase in the concentration of unburned components in the exhaust gas attendant on the deceleration operation, the unburned components can be burned in the exhaust system, with the result of clarification. [0030] Incidentally, also at the time of normal operation of the internal combustion engine E, the pressure pulsation in the exhaust system acts on the lower housing half lib, and, therefore, the reed 24 of the reed valve V is vibrated to open and close the valve hole. At the time of normal operation, however, the intake negative pressure is comparatively low and the control valve 15 is closed to shut off the secondary upstream passage 12a, so that the secondary air is not supplied to the exhaust port 6. [0031] Meanwhile, depending on the flow conditions of the gas in the surroundings of the reed 24, the reed 24 may undergo a torsional deformation about the longitudinal axis thereof. Even in such a case, since the pair of projections 27, 27 are provided on both inside surfaces on the sides of the major sides of the valve hole 21, these projections 27, 27 receive both side edge portions on the sides of the major sides of the reed 24, thereby restraining the twisting of the reed 24 and inhibiting the reed 24 from entering into the valve hole 21, so that the reed 24 can be led to normal seating onto the valve seat 22. [0032] As a result of tests, it has been confirmed that the twisting of the reed 24 is largest at a central portion in the longitudinal direction of the valve hole 21. It has also been confirmed that, taking into account the inclined fitting of the reed 24 due to errors in fitting the reed 24 to the reed fitting portion 20a, in the case where the valve hole 21 is formed in a roughly-rectangular shape whose longitudinal direction is the same as that of the reed 24, the effect of the projections 27, 27 of the valve hole 21 on restraining the twisting of the reed 24 is greatest when the projections 27, 27 are disposed at locations of about 75% of the major side length L of the valve hole 21, as measured from the end edge of the valve hole 21 on the side of the base end of the reed 24, as described above. With such an arrangement, therefore, it is possible to effectively restrain the twisting of the reed 24 while setting the projection length of the projections 27, 27 as small as possible, and to securely prevent the reed 24 from entering into the valve hole 21. [0033] In this way, it is possible to set the lap margin of the reed 24 in relation to the valve seat at the required minimum limit value for shutting off the valve hole 21, to obviate an increase in the spring constant of the reed, and to enhance the response characteristics of the reed to pressure pulsation. In addition, it is possible to contrive a reduction in size of the reed valve V while securing a desired flow rate of the gas. [0034] Besides, when such a reed valve V is used for supply of secondary air to the exhaust system of the internal combustion engine E as above-mentioned, the reed 24 always responds appropriately to the pulsation of the exhaust pressure, whereby secondary air can be securely supplied to the exhaust system, thereby contributing to clarification of the exhaust gas. [0035] Next, a second embodiment of the present invention shown in Figs. 5 and 6 will be described. [0036] The second embodiment resides in that a pair of projections 37, 3 7 are provided on both side edges on the sides of the major sides of the reed 24, in place of the projections 27, 27 on the valve hole 21 in the preceding embodiment. The other constitutions in the second embodiment are the same as those in the preceding embodiment. Therefore, in Figs. 5 and 6, the portions corresponding to those in the preceding embodiment are denoted by the same symbols as before, and description thereof is omitted. [0037] In this embodiment also, even if the reed 24 tends to enter into the valve hole 21 while being twisted about the longitudinal axis thereof, the projections 37, 37 on both side edges of the reed 24 are received by the valve seat 22 at both side edges of the valve hole 21, whereby the twisting of the reed 24 is restrained, and the reed 24 is prevented from entering into the valve hole 21, so that the reed 24 is led to normal seating onto the valve seat 22. Therefore, in this case also, it is possible to set the lap margin of the reed 24 in relation to the valve seat at the required minimum limit value for shutting off the valve hole 21, to obviate an increase in the spring constant of the reed, and to enhance the response characteristics of the reed to pressure pulsation. In addition, there is no particular reduction of the opening area of the valve hole 21 due to the presence of the above-mentioned projections 37, 37, so that it is possible to contrive a reduction in size of the reed valve V while securing a desired flow rate of the gas. [0038] In addition, when the reed valve V is used for supply of secondary air to the exhaust system of the internal combustion engine E as in the preceding embodiment, the reed 24 always responds appropriately to the pulsation of the exhaust pressure, whereby, naturally, the secondary air can be securely supplied to the exhaust system, thereby contributing to clarification of the exhaust gas. [0039] The present invention is not limited to the above embodiments, and various design modifications are possible without stepping out of the scope of the gist of the invention. [0040] [Effects of the Invention] As has been described above, according to the first characteristic feature of the present invention, in the reed valve which comprises the valve seat member comprising the valve seat and the valve hole opened at the valve seat, and the reed having the base end attached to the valve seat member and having the free end extending in the longitudinal direction thereof while covering the valve hole so as to open and close the valve hole in cooperation with the valve seat, the projection for inhibiting the reed from entering into the valve hole is provided on the inside surface along the longitudinal direction of the reed, of the valve hole. Therefore, even if the reed tends to enter into the valve hole while being twisted about the longitudinal axis thereof, the reed can be inhibited from entering into the valve hole. Accordingly, it is possible to set the lap margin of the reed in relation to the valve seat at the required minimum limit value for shutting off the valve hole, to obviate an increase in the spring constant of the reed, and to enhance response characteristics of the reed to pressure pulsation. In addition, it is possible to contrive a reduction in size of the reed valve while securing a desired flow rate of the gas. [0041] In addition, according to the second characteristic feature of the present invention, in the reed valve which comprises the valve seat member comprising the valve seat and the valve hole opened at the valve seat, and the reed having the base end attached to the valve seat member and having the free end extending in the longitudinal direction thereof while covering the valve hole so as to open and close the v^lve hole in cooperation with the valve seat, the projection for inhibiting the reed from entering into the valve hole is provided on the side edge along the longitudinal direction of the reed. Therefore, CTea it t-tve xeed t^rv&s- t.o. eater mtc tb.e vsA>re bia-Le wb/LLe being twisted about the longitudinal axis thereof, the reed can be inhibited from entering into the valve hole. As a result, it is possible to set the lap margin of the reed in relation to the valve seat at the required minimum limit value for shutting off the valve hole, to obviate an increase in the spring constant of the reed, and to enhance response characteristics of the reed to pressure pulsation. In addition, there is no particular reduction of the opening area of the valve hole due to the presence of the projection, and it is possible to contrive a reduction in size of the reed valve while securing a desired flow rate of the gas. [0042] Further, according to the third characteristic feature of the present invention, the valve hole is formed in a roughly rectangular shape whose longitudinal direction is the same as that of the reed, and the distance from the end edge of the valve hole on the side of the base end of tJie reed to the projection is set at about 75% of the major side length of the valve hole. Therefore, it is possible to effectively restrain the twisting of the reed while setting the projection length of the projection as small as possible, and to securely prevent the reed from entering into the valve hole. [0043] Furthermore, according to the fourth characteristic feature of the present invention, the reed valve is intermediately disposed in the secondary air passage connected to the exhaust -system of the internal combustion engine, with the reed directed toward the downstream side of the passage. Therefore, the reed always responds appropriately to the pressure pulsation in the exhaust system, and secondary air can be securely supplied to the exhaust system, thereby contributing to clarification of the exhaust gas. [Explanation of Symbols] 6 • 12 20 21 22 24J 27 37. E • L • L' • intake system (intake port) • secondary air passage • valve seat member • valve hole • valve seat v •• reed •projection on inside surface of valve •projection on side edge of reed • internal combustion engine • major side length of valve hole • distance from end edge of valve hole on the side We claim: 1. A reed valve which comprises a valve seat member (20) comprising a valve seat (22) and a valve hole (21) opening at said valve seat (22), and a reed (24) having a base end attached to said valve seat member (20) and having a free end extending in the longitudinal direction while covering said valve hole (21) so as to open and close said valve hole (21) in cooperation with said valve seat (22), wherein a projection (27) for inhibiting said reed (24) from entering into said valve hole (21) is provided on the inside surface along the longitudinal direction of said reed (24), of said valve hole (21). 2. A reed valve as claimed in claim 1, wherein a projection (37) for inhibiting said reed (24) from entering into said valve hole (21) is provided at a side edge along the longitudinal direction of said reed (24). 3. A reed valve as claimed in claim 1 or 2, wherein said valve hole (21) is formed in a roughly rectangular shape whose longitudinal direction is the same as that of said reed (24), and the distance (L') from the end edge of said valve hole (21) on the side of said base end of said reed (24) to said projection (27, 37) is set at about 75% of the major side length (L) of said valve hole (21). 4. A reed valve as claimed in any of claims 1 to 3, wherein said reed (24) is disposed in a secondary air passage (12) connected to an exhaust system (6) of an internal combustion engine (E), and directed toward the downstream side of said passage (12). 5. A reed valve substantially as hereinbefore described with reference to the accompanying drawings. Dated this: 3/02/2003 [JAYANTA PALI] OF REMFRY & SAGAR ATTORNEY FOR THE APPLICANT[S]

Documents:

143-mum-2003-abstract(21-8-2008).doc

143-mum-2003-abstract(21-8-2008).pdf

143-mum-2003-cancelled pages(21-8-2008).pdf

143-mum-2003-claims(granted)-(21-8-2008).doc

143-mum-2003-claims(granted)-(21-8-2008).pdf

143-mum-2003-correspondence(18-8-2008).pdf

143-MUM-2003-CORRESPONDENCE(27-08-2008).pdf

143-MUM-2003-CORRESPONDENCE(29-8-2008).pdf

143-mum-2003-correspondence(ipo)-(1-9-2008).pdf

143-mum-2003-drawing(21-8-2008).pdf

143-MUM-2003-ENGLISH TRANSLATION(29-8-2008).pdf

143-mum-2003-form 1(21-8-2008).pdf

143-mum-2003-form 1(4-2-2003).pdf

143-mum-2003-form 18(12-1-2007).pdf

143-mum-2003-form 2(granted)-(21-8-2008).doc

143-mum-2003-form 2(granted)-(21-8-2008).pdf

143-mum-2003-form 3(15-4-2004).pdf

143-mum-2003-form 3(21-8-2008).pdf

143-mum-2003-form 3(4-2-2003).pdf

143-mum-2003-form 5(21-8-2008).pdf

143-mum-2003-form 5(4-2-2003).pdf

143-mum-2003-petition under rule137(21-8-2008).pdf

143-mum-2003-petition under rule138(21-8-2008).pdf

143-mum-2003-power of authority(21-8-2008).pdf

143-mum-2003-power of authority(5-5-2003).pdf

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