Patent Application
20230167858
This application claims the benefit of priority to Japanese Patent Application No. 2021-194872 filed on Nov. 30, 2021. The entire contents of this application are hereby incorporated herein by reference.
The present invention relates to a vessel propulsion apparatus, a vessel, an auxiliary machine-equipped engine, and a torque fluctuation absorber.
Conventionally, in small vessels, automobiles, and others, air is compressed by using a supercharger and supplied to an engine. US 2007/0079796 A1 has disclosed an installation structure of a supercharger. According to this structure, a driving gear of the supercharger is provided with a one-way clutch as a torque fluctuation absorber. When an engine is decreased in rotational frequency upon deceleration or the like to result in a sudden torque fluctuation, the one-way clutch is actuated to absorb the torque fluctuation.
The inventor of preferred embodiments of the present invention described and claimed in the present application conducted an extensive study and research regarding a vessel propulsion apparatus, a vessel, an auxiliary machine-equipped engine, and a torque fluctuation absorber such as the one described above, and in doing so, discovered and first recognized new unique challenges and previously unrecognized possibilities for improvements as described in greater detail below.
Absorption of a torque fluctuation caused when an engine is increased in rotational frequency upon acceleration or the like of the engine is also preferable.
Preferred embodiments of the present invention provide vessel propulsion apparatuses, vessels, auxiliary machine-equipped engines, and torque fluctuation absorbers which are each capable of absorbing a bidirectional torque fluctuation.
In order to overcome the previously unrecognized and unsolved challenges described above, a preferred embodiment of the present invention provides a vessel propulsion apparatus including an engine that includes a crank shaft, a supercharger that includes an input shaft, a gear train that includes a plurality of gears to transmit a driving force from the crank shaft to the supercharger, and a torque fluctuation absorber to absorb a fluctuation in torque transmitted to the gear train. The torque fluctuation absorber includes a first outer helical spline, an intermediate member, an outer member, a first spring, and a second spring. The first outer helical spline is rotatable integrally with a torque transmission shaft which includes at least one of the crank shaft, the input shaft, and an intermediate shaft located in a torque transmission path from the crank shaft to the input shaft. The intermediate member coaxially surrounds the torque transmission shaft, and is able to move in a first axial direction and in a second axial direction which is an opposite direction to the first axial direction. The intermediate member includes a first inner helical spline on an inner circumference thereof and a second outer helical spline on an outer circumference thereof. The first inner helical spline is engaged with the first outer helical spline to provide a first helical spline coupling. The outer member coaxially surrounds the torque transmission shaft, and is regulated in axial movement with respect to the torque transmission shaft. The outer member includes teeth on an outer circumference thereof and a second inner helical spline on an inner circumference thereof. The teeth mesh with corresponding gears of the gear train. The second inner helical spline is engaged with the second outer helical spline to provide a second helical spline coupling. The first spring biases the intermediate member in the first axial direction. The second spring biases the intermediate member in the second axial direction.
According to this structural arrangement, the torque fluctuation absorber includes the intermediate member, the outer member, the first spring to bias the intermediate member in the first axial direction, and the second spring to bias the intermediate member in the second axial direction. The teeth which mesh with corresponding gears of the gear train are provided on the outer circumference of the outer member. The intermediate member coaxially surrounds the torque transmission shaft. The intermediate member is able to move in the first axial direction and in the second axial direction. The intermediate member is linked with the torque transmission shaft through the first helical spline coupling and linked with the outer member through the second helical spline coupling. When a torque fluctuation occurs in the torque transmission path, due to actions of the first and the second helical spline coupling, the intermediate member is moved in the second axial direction in resistance to the first spring. It is also moved in the first axial direction in resistance to the second spring. Therefore, it is possible to absorb a bidirectional torque fluctuation.
In a preferred embodiment of the present invention, the vessel propulsion apparatus further includes an inner member which coaxially surrounds the torque transmission shaft, is regulated in axial movement with respect to the torque transmission shaft, and is rotatable integrally with the torque transmission shaft. The first outer helical spline is provided on an outer circumference of the inner member. According to this structural arrangement, the inner member which surrounds the torque transmission shaft coaxially is regulated in axial movement with respect to the torque transmission shaft and is rotatable integrally with the torque transmission shaft. The first outer helical spline to provide the first helical spline coupling is provided on the outer circumference of the inner member. The torque fluctuation absorber may have a higher versatility by using the inner member.
In a preferred embodiment of the present invention, the torque fluctuation absorber further includes a base which coaxially surrounds the torque transmission shaft and is fixed to the torque transmission shaft. On an outer circumference of the base, the inner member is rotatable integrally therewith while being regulated in axial movement. The torque fluctuation absorber further includes a first support and a second support, each of which includes an annular linkage that is linked with the base and regulated in axial movement with respect to the base and an annular extension which extends outward in a radial direction from the annular linkage. The first support and the second support regulate an axial movement of the outer member between their respective extensions. The first spring is interposed between the annular extension of the first support and the intermediate member. The second spring is interposed between the annular extension of the second support and the intermediate member.
According to this structural arrangement, the inner member is able to rotate integrally with respect to the base fixed to the torque transmission shaft and also regulated in axial movement. The annular linkage of the first support and the annular linkage of the second support are linked with the base and also regulated in axial movement with respect to the base. Therefore, the first support and the second support are regulated in axial movement with respect to the base. The outer member is regulated in axial movement between the annular extension of the first support and the annular extension of the second support. When a torque fluctuation occurs in the torque transmission path, due to actions of the first or the second helical spline coupling, the intermediate member interposed between the outer member and the inner member is moved in the first axial direction or in the second axial direction. When the intermediate member is moved in the second axial direction, the first spring is compressed between the annular extension of the first support and the intermediate member. When the intermediate member is moved in the first axial direction, the second spring is compressed between the annular extension of the second support and the intermediate member. Therefore, it is possible to absorb a bidirectional torque fluctuation.
In a preferred embodiment of the present invention, at least one of the annular extension of the first support and the annular extension of the second support supports the outer member so as to rotate coaxially with the torque transmission shaft. According to this structural arrangement, it is possible to support the outer member so as to be rotatable coaxially with the torque transmission shaft by at least one of the annular extension of the first support and the annular extension of the second support.
In a preferred embodiment of the present invention, one of the annular extension of the first support and the annular extension of the second support supports the outer circumference of the outer member so as to be rotatable coaxially with the torque transmission shaft. The other of the annular extension of the first support and the annular extension of the second support supports the inner circumference of the outer member so as to be rotatable coaxially with the torque transmission shaft. According to this structural arrangement, it is possible to support each of the outer circumference and the inner circumference of the outer member so as to rotate by the annular extension of a corresponding support.
In a preferred embodiment of the present invention, at least one of the annular extension of the first support and the annular extension of the second support supports the intermediate member so as to be rotatable coaxially with the torque transmission shaft. According to this structural arrangement, it is possible to support the intermediate member so as to rotate coaxially with the torque transmission shaft by at least one of the annular extension of the first support and the annular extension of the second support.
In a preferred embodiment of the present invention, either one of the first support and the second support is unitary and integral with the base. The other of the first support and the second support is fitted onto the outer circumference of the base and supported while being regulated in axial movement with respect to the base. According to this structural arrangement, either one of the first support and the second support is integral with the base as a single member. Therefore, it is possible to make the structure simple.
In a preferred embodiment of the present invention, the torque fluctuation absorber further includes a housing which houses the inner member, the intermediate member, the first spring, and the second spring. The housing is defined by the base, the outer member, the first support, and the second support. According to this structural arrangement, it is possible to house the inner member, the intermediate member, the first spring, and the second spring in the housing defined by the base, the outer member, the first support, and the second support.
In a preferred embodiment of the present invention, the torque fluctuation absorber further includes a sub-assembly which includes the base, the inner member, the intermediate member, the outer member, the first spring, and the second spring. According to this structural arrangement, it is possible to assemble the sub-assembly in advance and incorporate the sub-assembly in the torque transmission shaft. It is, therefore, possible to improve ease of assembly.
In a preferred embodiment of the present invention, the first spring and the second spring have a different spring constant from each other. According to this structural arrangement, depending on a direction in which the intermediate member moves upon occurrence of a torque fluctuation, a spring load to resist the movement of the intermediate member is able to be different.
In a preferred embodiment of the present invention, the first spring has a larger spring constant than the second spring. According to this structural arrangement, the spring load of the first spring to resist a movement of the intermediate member in the second axial direction is able to be larger than the spring load of the second spring to resist a movement of the intermediate member in the first axial direction.
In a preferred embodiment of the present invention, the first spring includes a disc spring, and the second spring includes a helical compression spring. According to this structural arrangement, the disc spring as the first spring may be increased in spring constant progressively in relation to a flexing displacement. Therefore, a high spring load may be obtained in resistance to the movement of the intermediate member in the second axial direction. It is possible to enhance the effect of absorbing a torque fluctuation.
In a preferred embodiment of the present invention, at least one of the first inner helical spline and the second outer helical spline is inclined with respect to a central axis of the intermediate member so that the intermediate member is moved in the second axial direction, which is a direction in which the first spring is compressed when a positive torque is transmitted from the crank shaft to the supercharger. According to this structural arrangement, when a positive torque is transmitted from the crank shaft to the supercharger, the intermediate member is moved in the second axial direction, which is a direction in which the first spring higher in spring constant is compressed. Therefore, a torque fluctuation is effectively absorbed.
Another preferred embodiment of the present invention provides a vessel which includes the vessel propulsion apparatus. According to this structural arrangement, it is possible to provide the same effects as those of the vessel propulsion apparatus in each of the preferred embodiments described above.
Another preferred embodiment of the present invention provides an auxiliary machine-equipped engine which includes an engine that includes a crank shaft, an auxiliary machine that includes an input shaft, a gear train that includes a plurality of gears to transmit a driving force from the crank shaft to the auxiliary machine, and a torque fluctuation absorber to absorb a fluctuation in torque transmitted to the gear train. The torque fluctuation absorber includes a first outer helical spline, an intermediate member, an outer member, a first spring, and a second spring. The first outer helical spline is rotatable integrally with a torque transmission shaft that includes at least one of the crank shaft, the input shaft, and an intermediate shaft located in a torque transmission path from the crank shaft to the input shaft. The intermediate member coaxially surrounds the torque transmission shaft, and is able to move in a first axial direction and in a second axial direction which is an opposite direction to the first axial direction. The intermediate member includes a first inner helical spline on an inner circumference thereof. The first inner helical spline is engaged with the first outer helical spline to provide a first helical spline coupling. The intermediate member includes a second outer helical spline on an outer circumference thereof. The outer member coaxially surrounds the torque transmission shaft, and is regulated in axial movement with respect to the torque transmission shaft. The outer member includes teeth on an outer circumference thereof. The teeth mesh with corresponding gears of the gear train. The outer member includes a second inner helical spline on an inner circumference thereof. The second inner helical spline is engaged with the second outer helical spline to provide a second helical spline coupling. The first spring biases the intermediate member in the first axial direction. The second spring biases the intermediate member in the second axial direction.
According to this structural arrangement, the intermediate member is linked with the torque transmission shaft through the first helical spline coupling and linked with the outer member through the second helical spline coupling. When a torque fluctuation occurs in the torque transmission path, due to actions of the first or the second helical spline coupling, the intermediate member is moved in the second axial direction in resistance to the first spring or moved in the first axial direction in resistance to the second spring. Therefore, it is possible to absorb a bidirectional torque fluctuation in the auxiliary machine-equipped engine.
Another preferred embodiment of the present invention provides a torque fluctuation absorber to absorb a fluctuation in torque transmitted to a gear train including a plurality of gears. The torque fluctuation absorber includes a first outer helical spline, an intermediate member, an outer member, a first spring, and a second spring. The first outer helical spline is rotatable integrally with a torque transmission shaft. The intermediate member coaxially surrounds the torque transmission shaft, and is able to move in a first axial direction and in a second axial direction which is an opposite direction to the first axial direction. The intermediate member includes a first inner helical spline on an inner circumference thereof. The first inner helical spline is engaged with the first outer helical spline to provide a first helical spline coupling. The intermediate member includes a second outer helical spline on an outer circumference thereof. The outer member coaxially surrounds the torque transmission shaft, and is regulated in axial movement with respect to the torque transmission shaft. The outer member includes teeth on an outer circumference thereof. The teeth mesh with corresponding gears of the gear train. The outer member includes a second inner helical spline on an inner circumference thereof. The second inner helical spline is engaged with the second outer helical spline to provide a second helical spline coupling. The first spring biases the intermediate member in the first axial direction. The second spring biases the intermediate member in the second axial direction.
According to this structural arrangement, the intermediate member is linked with the torque transmission shaft through the first helical spline coupling and linked with the outer member through the second helical spline coupling. When a torque fluctuation occurs in a torque transmission path, due to actions of the first or the second helical spline coupling, the intermediate member is moved in the second axial direction in resistance to the first spring or moved in the first axial direction in resistance to the second spring. Therefore, it is possible to absorb a bidirectional fluctuation in torque transmitted to the gear train.
The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.
The vessel body 101 includes a hull 105 which floats on the surface of water and a deck 106 which is located higher than the water surface. The deck 106 is located above the hull 105 which provides the vessel bottom. The engine 120 is located between the hull 105 and the deck 106 in an up/down direction. The engine 120 is located inside an engine room provided in an interior of the vessel body 101. The jet pump 102 is located behind the engine 120.
The jet pump 102 includes an intake 107 which is open at the vessel bottom, an outlet 108 which jets rearward water suctioned through the intake 107, and a flow channel 109 which guides the water suctioned through the intake 107 to the outlet 108. The jet pump 102 further includes an impeller 110 (rotor vane) and a stator vane 111 which are disposed in the flow channel 109 as well as a drive shaft 112 which rotates together with the impeller 110. The jet pump 102 also includes a nozzle 113 which defines the outlet 108 and a deflector 114 which deflects the direction of water flow that flows rearward from the nozzle 113 to the right side or the left side. The deflector 114 defines a jet port 115 which opens rearward.
An output of the engine 120 is adjusted by a crew member that operates a throttle lever provided in the handle 103. When the engine 120 rotates the drive shaft 112, the impeller 110 is rotated around a center line of the drive shaft 112 generating a suction force that suctions water outside the vessel from the intake 107 to the flow channel 109. The water suctioned into the flow channel 109 passes through the impeller 110, the stator vane 111, the nozzle 113, and the deflector 114 in this order and is jetted rearward from the jet port 115 of the deflector 114. Thus, a thrust to propel the vessel 100 forward is generated. Further, the deflector 114 is pivoted from side to side depending on operation of the handle 103 and, therefore, a direction in which water is jetted from the jet pump 102 is changed to the right side or to the left side depending on the operation of the handle 103. Thus, the vessel 100 is steered.
The engine 120 is an internal combustion engine. The engine 120 includes a crank shaft 1 capable of rotating around a crank axis Ac that extends in a front and rear direction. The engine 120 includes a plurality of cylinders 122 which respectively house a plurality of pistons 121 that reciprocate in an up/down direction and a connecting rod 123 that links each of the plurality of pistons 121 with the crank shaft 1.
The engine 120 further includes a supercharger 130, a gear train GT which transmits a driving force from the crank shaft 1 to the supercharger 130, and a torque fluctuation absorber TFA which absorbs a fluctuation in torque transmitted to the gear train GT.
The ventilation channel 131 connects the supercharger 130 with each of the cylinders 122 of the engine 120. Compressed air which has been compressed by the supercharger 130 passes through the ventilation channel 131 and flows into each of the cylinders 122. The intercooler 132 is located in the ventilation channel 131. The intercooler 132 is located to cool high-temperature compressed air flowing through the ventilation channel 131.
The gear train GT includes a plurality of gears to transmit a driving force of the crank shaft 1 to the supercharger 130. A preferred example of the gear train GT includes a driving gear G1, a first intermediate gear G2, a second intermediate gear G3, and a driven gear G4.
The supercharger 130 includes a housing 133 which includes an air intake port 134 and an ejection port 135. The housing 133 is installed on an installation portion 124 provided at the front end 120b of the body 120a of the engine 120. The air intake port 134 takes in air fed from an air intake box BX. The ejection port 135 sends the air taken in from the air intake port 134 to the intercooler 132. A rotary portion 136 is installed in an interior of the housing 133. The rotary portion 136 includes an input shaft 137 and an impeller 138. The input shaft 137 is supported by the housing 133 so as to rotate through a bearing 139. The impeller 138 is linked with one end portion of the input shaft 137 and rotates integrally with the input shaft 137. The impeller 138 is disposed inside the air intake port 134.
As the driven gear G4, an input gear is installed on the other end portion of the input shaft 137. The driven gear G4 is linked with the driving gear G1 through the first intermediate gear G2 and the second intermediate gear G3. The first intermediate gear G2 and the second intermediate gear G3 are located coaxially on an intermediate shaft 140 functioning as a torque transmission shaft which is located in a torque transmission path from the crank shaft 1 to the input shaft 137 of the supercharger 130. The intermediate shaft 140 is a hollow shaft. A supporting shaft 150 which is fixed to the housing 133 is inserted into the intermediate shaft 140. A central axis of the supporting shaft 150 and a central axis of the intermediate shaft 140 are parallel or substantially parallel to the crank axis Ac. The intermediate shaft 140 is supported by the supporting shaft 150 so as to rotate through a bearing (not shown).
The first intermediate gear G2 and the second intermediate gear G3 are located on an outer circumference of the intermediate shaft 140 and separated in an axial direction of the intermediate shaft 140. The first intermediate gear G2 and the second intermediate gear G3 rotate integrally with the intermediate shaft 140. The first intermediate gear G2 is engaged with the driving gear G1. The second intermediate gear G3 is engaged with the driven gear G4. When the crank shaft 1 is rotated by actuation of the engine 120, a rotary force thereof is transmitted to the input shaft 137 through the gear train GT which includes the driving gear G1, the first intermediate gear G2, the second intermediate gear G3, and the driven gear G4. Thus, the impeller 138 is rotated. Air which is introduced into the air intake port 134 is compressed by the rotation of the impeller 138 and ejected from the ejection port 135. The compressed air ejected from the ejection port 135 is cooled by the intercooler 132 and, thereafter, supplied to each of the cylinders 122 of the engine 120.
The first outer helical spline 31 is provided on an outer circumference 3a of the inner member 3. The first inner helical spline 41 is provided on an inner circumference 4b of the intermediate member 4. The first outer helical spline 31 and the first inner helical spline 41 are engaged with each other to provide a first helical spline coupling HC1. The second outer helical spline 42 is provided on an outer circumference 4a of the intermediate member 4. The second inner helical spline 52 is provided on an inner circumference 5b of the outer member 5. The second outer helical spline 42 and the second inner helical spline 52 are engaged with each other to provide a second helical spline coupling HC2.
As shown in
The inner peripheral spline 2e is provided on the inner circumference 2b. The base 2 is fitted onto an outer circumference 1a of the crank shaft 1. The base 2 is spline-coupled to the crank shaft 1. The inner peripheral spline 2e is engaged with an outer peripheral spline 1b on the outer circumference 1a of the crank shaft 1. Thus, the base 2 is coupled to the crank shaft 1 so as to rotate integrally therewith. The inner circumference flange 2f is an annular flange which extends inward in a radial direction from the inner circumference 2b. The inner circumference flange 2f abuts against an end surface 1c of the crank shaft 1. The inner circumference flange 2f is fastened to the end surface 1c of the crank shaft 1 by a fixing screw 12, which is an example of a fastening member that penetrates through the inner circumference flange 2f. Thus, the base 2 is fixed to the crank shaft 1.
The base 2 is integral with the first supporting member 8 as a single member. The first supporting member 8 is an annular member which extends outward in a radial direction from the one end 2c of the base 2. The first outer peripheral spline 2g, the second outer peripheral spline 2h, and the outer circumference groove 2j are provided on the outer circumference 2a. The first outer peripheral spline 2g is located adjacent to the one end 2c. The second outer peripheral spline 2h extends from the other end 2d up to a position adjacent to the first outer peripheral spline 2g.
The second supporting member 9 is an annular member. The second supporting member 9 is fitted onto the outer circumference 2a of the base 2. The second supporting member 9 is spline-coupled to the second outer peripheral spline 2h on the outer circumference 2a of the base 2. Thus, the second supporting member 9 is coupled to the base 2 so as to rotate integrally therewith. An axial movement of the second supporting member 9 with respect to the base 2 is regulated by a regulating member. An axial movement of the second supporting member 9 with respect to the base 2 is regulated by the retaining ring 11, which is an example of the regulating member that is fitted onto the outer circumference groove 2j. Thus, the second supporting member 9 is regulated in axial movement with respect to the crank shaft 1.
The inner member 3 is a ring-shaped member which coaxially surrounds the crank shaft 1. The inner member 3 rotates integrally with the crank shaft 1. The inner member 3 coaxially surrounds the base 2. The inner member 3 includes the outer circumference 3a, an inner circumference 3b, one end 3c, and the other end 3d in an axial direction, an inner peripheral spline 3e, and a first outer helical spline 31. The inner peripheral spline 3e is a straight spline which is provided on the inner circumference 3b. The inner member 3 is spline-coupled to the outer circumference 3a of the base 2. The inner peripheral spline 3e of the inner member 3 is engaged with the first outer peripheral spline 2g of the base 2. Thus, the inner member 3 rotates integrally with the base 2.
The inner member 3 is held in an axial direction between the first supporting member 8 and the second supporting member 9. The one end 3c of the inner member 3 abuts against the first supporting member 8. The other end 3d of the inner member 3 abuts against the second supporting member 9. Thus, the inner member 3 is regulated in axial movement with respect to the base 2. The inner member 3 is held on the outer circumference 2a of the base 2 so as to rotate integrally therewith in a state of being regulated in axial movement. The inner member 3 is regulated in axial movement with respect to the crank shaft 1. The first outer helical spline 31 is provided on the outer circumference 3a of the inner member 3.
The intermediate member 4 is a ring-shaped member which coaxially surrounds the crank shaft 1. The intermediate member 4 coaxially surrounds the inner member 3. The intermediate member 4 is helical spline-coupled to the inner member 3. The intermediate member 4 includes the outer circumference 4a, the inner circumference 4b, an end surface 4c and an end surface 4d in an axial direction, the first inner helical spline 41, the second outer helical spline 42, the housing recessed portion 4e, and an annular raised portion 4f.
The first inner helical spline 41 is provided on the inner circumference 4b of the intermediate member 4. The first inner helical spline 41 of the intermediate member 4 is engaged with the first outer helical spline 31 of the inner member 3. The first outer helical spline 31 and the first inner helical spline 41 are engaged with each other to provide the first helical spline coupling HC1. The second outer helical spline 42 is provided on the outer circumference 4a of the intermediate member 4.
One end surface 4c faces the first supporting member 8. The housing recessed portion 4e is an annular recessed portion which is provided on the one end surface 4c and is coaxial with the ring-shaped intermediate member 4. The first spring 6 is housed in the housing recessed portion 4e. The annular raised portion 4f protrudes from the other end surface 4d in the first axial direction X1. The annular raised portion 4f is coaxial with the ring-shaped intermediate member 4. The annular raised portion 4f is coaxial with the crank shaft 1. The annular raised portion 4f includes an outer peripheral surface 4g and an inner peripheral surface 4h which are coaxial with the crank shaft 1.
The outer member 5 is a ring-shaped member which coaxially surrounds the crank shaft 1. The outer member 5 is regulated in axial movement with respect to the crank shaft 1. The outer member 5 coaxially surrounds the intermediate member 4. The outer member 5 is helical spline-coupled to the intermediate member 4. The outer member 5 includes an outer circumference 5a, the inner circumference 5b, an end surface 5c and an end surface 5d in an axial direction, an inner peripheral recessed portion 5e, an annular step portion 5f, an outer peripheral recessed portion 5g, a plurality of teeth 5h, and a second inner helical spline 52. The plurality of teeth 5h are provided on the outer circumference 5a of the outer member 5.
The plurality of teeth 5h mesh with the first intermediate gear G2. The second inner helical spline 52 is provided on the inner circumference 5b of the outer member 5. The second inner helical spline 52 of the outer member 5 is engaged with the second outer helical spline 42 of the intermediate member 4. The second helical spline coupling HC2 is provided by the second inner helical spline 52 of the outer member 5 and the second outer helical spline 42 of the intermediate member 4.
One end surface 5c is adjacent to the first supporting member 8. The other end surface 5d faces the second supporting member 9. The inner peripheral recessed portion 5e is provided on the inner circumference 5b and opens to the one end surface 5c. The inner peripheral recessed portion 5e is coaxial with respect to the ring-shaped outer member 5. The inner peripheral recessed portion 5e is a cylindrical surface which is coaxial with the crank shaft 1. The inner peripheral recessed portion 5e is an example of a supported portion which is supported by the first supporting member 8. The annular step portion 5f is a step portion perpendicular or substantially perpendicular to the inner peripheral recessed portion 5e and parallel or substantially parallel to the one end surface 5c. The annular step portion 5f as an example of a held-between portion. The annular step portion 5f is a surface which is perpendicular or substantially perpendicular to the crank axis Ac.
The outer peripheral recessed portion 5g is provided on the outer circumference 5a and opens to the other end surface 5d. The other end surface 5d is a preferred example of the held-between portion. The outer peripheral recessed portion 5g is coaxial with respect to the ring-shaped outer member 5. The outer peripheral recessed portion 5g is a cylindrical surface which is coaxial with the crank axis Ac. The outer peripheral recessed portion 5g is an example of a supported portion which is supported by the second supporting member 9.
The first supporting member 8 is a ring-shaped member which is coaxial with the crank shaft 1. The first supporting member 8 includes an annular linkage portion 8a, an annular extension portion 8b, an end surface 8c and an end surface 8d in an axial direction, an outer peripheral surface 8e, an annular raised portion 8f, and an annular raised portion 8g. The annular linkage portion 8a of the first supporting member 8 is linked integrally with the one end 2c of the base 2. The annular extension portion 8b extends outward in a radial direction from the annular linkage portion 8a. One end surface 8c defines a portion of an outer surface of the driving gear G1. The outer peripheral surface 8e of the first supporting member 8 is equivalent to an outer peripheral surface of the extension portion 8b. The outer peripheral surface 8e is a cylindrical surface which is coaxial with the crank shaft 1. The outer peripheral surface 8e is fitted into the inner peripheral recessed portion 5e of the outer member 5. Thus, the extension portion 8b of the first supporting member 8 has a function of supporting the outer member 5 so as to rotate coaxially with the crank shaft 1.
The annular raised portion 8f is provided on the other end surface 8d so as to be adjacent to the outer peripheral surface 8e. The annular raised portion 8f is in contact with the annular step portion 5f of the outer member 5 so as to slide thereon. The annular raised portion 8f has a function of regulating an axial movement of the outer member 5. Thus, the extension portion 8b of the first supporting member 8 has the function of regulating an axial movement of the outer member 5.
The annular raised portion 8g is located farther inward in a radial direction than the annular raised portion 8f in the extension portion 8b. The annular raised portion 8g protrudes from the other end surface 8d. The annular raised portion 8g is coaxial with the ring-shaped first supporting member 8. The annular raised portion 8g is coaxial with the crank shaft 1. The annular raised portion 8g includes an outer circumference 8h, an inner circumference 8j, and a top portion 8k that is an example of a receiving portion. The outer circumference 8h and the inner circumference 8j of the annular raised portion 8g define a cylindrical surface which is coaxial with the crank shaft 1. The annular raised portion 8g is fitted into the housing recessed portion 4e of the one end surface 5c of the intermediate member 4. Thus, the first supporting member 8 has a function of supporting the intermediate member 4 so as to rotate coaxially with the crank shaft 1. The extension portion 8b of the first supporting member 8 also has a function of supporting the intermediate member 4 so as to move in an axial direction.
The first spring 6 is interposed between the extension portion 8b of the first supporting member 8 and the intermediate member 4. The first spring 6 is flexed between the extension portion 8b of the first supporting member 8 and the intermediate member 4. The first spring 6 biases the intermediate member 4 in the first axial direction X1. The first spring 6 is interposed between the top portion 8k of the annular raised portion 8g provided in the extension portion 8b of the first supporting member 8 and the bottom of the housing recessed portion 4e of the intermediate member 4. The first spring 6 biases the intermediate member 4 in the first axial direction X1.
The second supporting member 9 is a ring-shaped member which is coaxial with the crank shaft 1. The second supporting member 9 includes an annular linkage portion 9a, an annular extension portion 9b, an end surface 9c and an end surface 9d in an axial direction, an outer circumference 9e, an annular raised portion 9f, the housing recessed portion 9g, and an annular recessed portion 9h. The annular linkage portion 9a of the second supporting member 9 is linked integrally with the other end 2d of the base 2. The annular linkage portion 9a of the second supporting member 9 is spline-coupled to the outer circumference 2a of the base 2. An inner peripheral spline 9j which is a straight spline provided in the linkage portion 9a is engaged with the second outer peripheral spline 2h on the outer circumference 2a of the base 2. The second supporting member 9 rotates integrally with the base 2. The annular extension portion 8b extends outward in a radial direction from the annular linkage portion 8a. The outer circumference 9e of the second supporting member 9 is equivalent to an outer circumference of the extension portion 9b. One end surface 9c is also an outer surface of the driving gear G1.
The annular raised portion 9f protrudes from the other end surface 9d in the extension portion 9b. The annular raised portion 9f is located adjacent to the outer circumference 9e. An inner peripheral surface 9k of the annular raised portion 9f is a cylindrical surface coaxial with the crank shaft 1. The inner peripheral surface 9k of the annular raised portion 9f is fitted into the outer peripheral recessed portion 5g of the outer member 5 so as to slide thereon. Thus, the extension portion 9b of the second supporting member 9 provides the function of supporting the outer member 5 so as to rotate coaxially with the crank shaft 1. The annular raised portion 9f is in contact with the other end surface 5d of the outer member 5 so as to slide thereon. Thus, the extension portion 9b of the second supporting member 9 provides the function of regulating an axial movement of the outer member 5.
The housing recessed portion 9g and the annular recessed portion 9h are provided on the other end surface 9d in the extension portion 9b. The housing recessed portion 9g is located farther outward in a radial direction than the annular recessed portion 9h. The housing recessed portion 9g is coaxial with the ring-shaped second supporting member 9. The housing recessed portion 9g is coaxial with the crank shaft 1. The annular raised portion 4f of the intermediate member 4 is fitted into the housing recessed portion 9g so as to slide thereon. Thus, the extension portion 9b of the second supporting member 9 has the function of supporting the intermediate member 4 so as to rotate coaxially with the crank shaft 1. The extension portion 9b of the second supporting member 9 also has the function of supporting the intermediate member 4 so as to move in an axial direction.
The housing recessed portion 9g houses the second spring 7. The second spring 7 is interposed between the extension portion 9b of the second supporting member 9 and the intermediate member 4. The second spring 7 is flexed between the extension portion 9b of the second supporting member 9 and the intermediate member 4. The second spring 7 biases the intermediate member 4 in the second axial direction X2. A preferred example of the second spring 7 is a helical compression spring. The second spring 7 is interposed between the bottom of the annular recessed portion 9h provided in the extension portion 9b of the second supporting member 9 and the other end surface 4d of the intermediate member 4. The bottom portion 10b of the spring guide 10 is interposed between the other end surface 4d of the intermediate member 4 and the second spring 7. The bottom portion 10b is slidable with respect to the other end surface 4d.
Due to being surrounded by the base 2, the outer member 5, the first supporting member 8, and the second supporting member 9, a housing space SS is provided in which the inner member 3, the intermediate member 4, the first spring 6, and the second spring 7 are housed.
Here, in order that the intermediate member 4 is able to be moved axially, there is provided a relationship shown by the following formula between the torsion angle β1 of the first inner helical spline 41 and the torsion angle β2 of the second outer helical spline 42. However, a pitch circle diameter of the first inner helical spline 41 is given as D1, and a pitch circle diameter of the second outer helical spline 42 is given as D2.
π×D1/tanβ1=π×D2/tanβ2
According to the present preferred embodiment, in the torque fluctuation absorber TFA and also in the vessel propulsion apparatus P1 including the torque fluctuation absorber TFA, the following effects are obtained. That is, as shown in
According to this structural arrangement, the intermediate member 4 coaxially surrounds the crank shaft 1 which is an example of the torque transmission shaft TT. The intermediate member 4 is able to move in the first axial direction X1 and in the second axial direction X2. The intermediate member 4 is linked with the crank shaft 1 through the first helical spline coupling HC1 and linked with the outer member 5 through the second helical spline coupling HC2. When a torque fluctuation occurs in a torque transmission path, due to actions of the first helical spline coupling HC1 and the second helical spline coupling HC2, the intermediate member 4 is moved in the second axial direction X2 in resistance to the first spring 6. It is also moved in the first axial direction X1 in resistance to the second spring 7. Therefore, it is possible to absorb a bidirectional torque fluctuation.
The torque fluctuation absorber TFA further includes a ring-shaped inner member 3 which coaxially surrounds a crank shaft 1 (torque transmission shaft TT). The inner member 3 is regulated in axial movement with respect to the crank shaft 1 and also rotates integrally with the crank shaft 1. The first outer helical spline 31 provides the first helical spline coupling HC1 provided on an outer circumference 3a of the inner member 3. The torque fluctuation absorber TFA may have a higher versatility by using the inner member 3.
The torque fluctuation absorber TFA also includes a ring-shaped base 2 which coaxially surrounds the crank shaft 1 (torque transmission shaft TT) and is fixed to the crank shaft 1. On an outer circumference 2a of the base 2, the inner member 3 is held so as to rotate integrally in a state of being regulated in axial movement. The torque fluctuation absorber TFA further includes a first supporting member 8 and a second supporting member 9. The first supporting member 8 includes an annular linkage portion 8a which is linked with the base 2 in a state of being regulated in axial movement with respect to the base 2 and an annular extension portion 8b which extends outward in a radial direction from the linkage portion 8a. The second supporting member 9 includes an annular linkage portion 9a which is linked with the base 2 in a state of being regulated in axial movement with respect to the base 2 and an annular extension portion 9b which extends outward in a radial direction from the linkage portion 9a. The first supporting member 8 and the second supporting member 9 regulate an axial movement of the outer member 5 between their respective extension portions 8b, 9b. The first spring 6 is interposed between the extension portion 8b of the first supporting member 8 and the intermediate member 4. The second spring 7 is interposed between the extension portion 9b of the second supporting member 9 and the intermediate member 4.
According to this structural arrangement, the inner member 3 rotates integrally with respect to the base 2 fixed to the crank shaft 1 and also regulated in axial movement. The linkage portion 8a of the first supporting member 8 and the linkage portion 9a of the second supporting member 9 are linked with the base 2 and also regulated in axial movement with respect to the base 2. Therefore, the first supporting member 8 and the second supporting member 9 are regulated in axial movement with respect to the base 2. The outer member 5 is regulated in axial movement between the extension portion 8b of the first supporting member 8 and the extension portion 9b of the second supporting member 9. When a torque fluctuation occurs in the torque transmission path, due to actions of the first helical spline coupling HC1 and the second helical spline coupling HC2, the intermediate member 4 interposed between the outer member 5 and the inner member 3 is moved in the first axial direction X1 or in the second axial direction X2. When the intermediate member 4 is moved in the second axial direction X2, the first spring 6 is compressed between the extension portion 8b of the first supporting member 8 and the intermediate member 4. When the intermediate member 4 is moved in the first axial direction X1, the second spring 7 is compressed between the extension portion 9b of the second supporting member 9 and the intermediate member 4. Therefore, it is possible to absorb a bidirectional torque fluctuation.
Further, the outer member 5 is supported so as to rotate coaxially with the crank shaft 1 by the extension portion 8b of the first supporting member 8 and the extension portion 9b of the second supporting member 9. Although not shown, the outer member 5 may be supported so as to rotate coaxially with the crank shaft 1 by only one of the extension portion 8b of the first supporting member 8 and the extension portion 9b of the second supporting member 9.
Further, the extension portion 8b of the first supporting member 8 supports an inner circumference 5b of the outer member 5 so as to rotate coaxially with the crank shaft 1. The extension portion 9b of the second supporting member 9 supports an outer circumference 5a of the outer member 5 so as to rotate coaxially with the crank shaft 1. According to this structural arrangement, it is possible to support each of the outer circumference 5a and the inner circumference 5b of the outer member 5 so as to rotate by the extension portion 8b, 9b of a corresponding supporting member 8, 9. Although not shown, the extension portion 8b of the first supporting member 8 may support the outer circumference 5a of the outer member 5 so as to rotate coaxially with the crank shaft 1, and the extension portion 9b of the second supporting member 9 may support the inner circumference 5b of the outer member 5 so as to rotate coaxially with the crank shaft 1.
It is also possible to support the intermediate member 4 so as to rotate coaxially with the crank shaft 1 (torque transmission shaft TT) by the extension portion 8b of the first supporting member 8 and the extension portion 9b of the second supporting member 9. Although not shown, the intermediate member 4 may be supported so as to rotate coaxially with the crank shaft 1 (torque transmission shaft TT) by only one of the extension portion 8b of the first supporting member 8 and the extension portion 9b of the second supporting member 9.
Further, one of the first supporting member 8 and the second supporting member 9 (the first supporting member 8 in the present preferred embodiment) is integral with the base 2 as a single member. The other of the first supporting member 8 and the second supporting member 9 (the second supporting member 9 in the present preferred embodiment) is fitted onto the outer circumference 2a of the base 2 and supported in a state of being regulated in axial movement with respect to the base 2. According to this structural arrangement, one of the first supporting member 8 and the second supporting member 9 is integral with the base 2 as a single member. It is, therefore, possible to make the structure simple. The second supporting member 9 may be integral with the base 2 as a single member, and the first supporting member 8 may be fitted onto the outer circumference 2a of the base 2 and supported in a state of being regulated in axial movement with respect to the base 2.
Further, due to being surrounded by the base 2, the outer member 5, the first supporting member 8, and the second supporting member 9, a housing space SS is provided in which the inner member 3, the intermediate member 4, the first spring 6, and the second spring 7 are housed. According to this structural arrangement, it is possible to house the inner member 3, the intermediate member 4, the first spring 6, and the second spring 7 in the housing space SS which is defined by the base 2, the outer member 5, the first supporting member 8, and the second supporting member 9.
Further, a sub-assembly SA (refer to
Further, the first spring 6 and the second spring 7 have a different spring constant from each other. According to this structural arrangement, depending on a direction in which the intermediate member 4 moves upon occurrence of a torque fluctuation, a spring load to resist the movement of the intermediate member 4 is different.
Further, the first spring 6 has a larger spring constant than the second spring 7. According to this structural arrangement, it is possible to increase a spring load of the first spring 6 to resist a movement of the intermediate member 4 in the second axial direction X2 than a spring load of the second spring 7 to resist a movement of the intermediate member 4 in the first axial direction X1.
Further, the first spring 6 includes a disc spring, and the second spring 7 includes a helical compression spring. According to this structural arrangement, the disc spring as the first spring 6 has a progressively increasing spring constant in relation to a flexing displacement. Therefore, a high spring load is obtained in resistance to movement of the intermediate member 4 in the second axial direction X2. It is possible to enhance the effect of absorbing a torque fluctuation.
Further, when a positive torque PT is transmitted from the crank shaft 1 to the supercharger 130, the intermediate member 4 is moved in the second axial direction X2 which is a direction in which the first spring 6 is compressed (refer to
The crankcase 170 includes an oil path 171 which extends in an up/down direction. One end 172 (upper end) of the oil path 171 is communicatively connected to the bearing clearance 301. The other end of the oil path 171 (not shown) is connected to the oil pump 190 through an oil path (not shown). Oil is fed under pressure and supplied from the oil pump 190 through the oil path 171 to the bearing clearance 301 of the journal bearing 300.
The crank shaft 1 includes a screw hole 1e and at least one oil path L1 extending in a radial direction. The fixing screw 12 is screwed into the screw hole 1e. An oil path L2 is provided in the screw hole 1e between the tip of the fixing screw 12 and the bottom of the screw hole 1e. The oil path L1 communicatively connects the bearing clearance 301 of the journal bearing 300 with the oil path L2 at the bottom of the screw hole 1e.
The fixing screw 12 is, for example, a bolt and includes a head 12a and a shank 12b. The shank 12b includes an under-head portion 12c, a screw shank 12d, an oil path L3 extending in an axial direction, and an oil path L4 extending in a radial direction. The under-head portion 12c is adjacent to the head 12a. The screw shank 12d extends from a position adjacent to the under-head portion 12c to a tip 12e of the shank 12b. The screw shank 12d is screwed and fitted into the screw hole 1e of the crank shaft 1. An outer circumference 12f of the under-head portion 12c is provided by a cylindrical surface which is free of threads. An outer diameter of the outer circumference 12f of the under-head portion 12c is smaller than an inner diameter of the screw hole 1e of the crank shaft 1. A portion of an inner circumference of the screw hole 1e which surrounds the under-head portion 12c may be defined by a cylindrical surface which is free of internal threads. A tubular oil path L5 is provided between the outer circumference 12f of the under-head portion 12c and the inner circumference of the screw hole 1e of the crank shaft 1.
In the fixing screw 12, the oil path L3 in an axial direction is defined by an axial direction hole which extends from the tip 12e of the shank 12b up to a midway portion of the under-head portion 12c in the axial direction. The oil path L3 includes one end L3a and the other end L3b. The one end L3a of the oil path L3 is communicatively connected with the oil path L2. The oil path L4 extending in a radial direction is defined by a radial direction hole which communicatively connects the other end L3b of the oil path L3 in an axial direction with the tubular oil path L5.
At least one oil path L6 extending in a radial direction is provided between the end surface 1c of the crank shaft 1 and the inner circumference flange 2f of the base 2. The oil path L6 is defined by, for example, a radial direction groove that is provided on the end surface 1c of the crank shaft 1. A tubular oil path L7 is provided between the inner circumference 2b of the base 2 and the outer circumference 1a in a tip portion of the crank shaft 1. The base 2 defines at least one oil path L8 which communicatively connects the tubular oil path L7 with the housing space SS. The oil path L8 is defined by a radial direction hole which penetrates through the outer circumference 2a and the inner circumference 2b of the base 2.
Oil which has been supplied from the oil pump 190 to the bearing clearance 301 of the journal bearing 300 is supplied to the oil path L1 of the crank shaft 1. The oil which has been supplied to the oil path L1 is supplied to the housing space SS through the oil path L2, the oil path L3, the oil path L4, the oil path L5, the oil path L6, the oil path L7 and the oil path L8. One preferred example of the oil path L which supplies oil to the housing space SS includes the oil path L1, the oil path L2, the oil path L3, the oil path L4, the oil path L5, the oil path L6, the oil path L7, and the oil path L8.
At least one oil path L9 is provided between the other end 3d of the inner member 3 and the other end surface 9d of the second supporting member 9. The oil path L9 is defined by a groove extending in a radial direction which is located at least in one of the other end 3d of the inner member 3 and the other end surface 9d of the second supporting member 9. A tubular oil path L10 which surrounds the inner member 3 along the outer circumference 3a of the inner member 3 is provided outside the inner member 3 in a radial direction. The oil path L9 communicatively connects the oil path L8 with the oil path L10 located outside the inner member 3 in a radial direction.
Inside the housing recessed portion 4e of the intermediate member 4, a housing space S1 which houses the first spring 6 is defined by the annular raised portion 8g of the first supporting member 8. An oil path L11 is provided in the annular raised portion 8g of the first supporting member 8. The oil path L11 communicatively connects the oil path L10 located outside the inner member 3 in a radial direction with the housing space S1. The oil path L11 is defined by a through hole 8n which penetrates through the annular raised portion 8g. One end of the through hole 8n is open at the inner circumference 8j of the annular raised portion 8g. The other end of the through hole 8n is open at the top portion 8k of the annular raised portion 8g. Inside the housing space SS, oil is supplied from the oil path L10 located outside the inner member 3 in a radial direction through the oil path L11 to the housing space S1 in which the first spring 6 is housed.
A housing space S2 to house the second spring 7 is provided inside the annular recessed portion 9h of the second supporting member 9. The oil path L10 located outside the inner member 3 in a radial direction is communicatively connected with the housing space S2. Inside the housing space SS, oil is supplied from the oil path L10 located outside the inner member 3 in a radial direction to the housing space S2 that houses the second spring 7. The second supporting member 9 provides an oil path L12 which communicatively connects the housing space S2 with the outside of the housing space SS. The oil path L12 is defined by a through hole which is open at the one end surface 9c of the second supporting member 9 and at the bottom of the annular recessed portion 9h.
According to this structural arrangement, the torque fluctuation absorber TFA includes the oil path L which supplies oil to the housing space SS. Therefore, each sliding portion of the torque fluctuation absorber TFA is lubricated and also cooled by the oil supplied to the housing space SS. When the intermediate member 4 is moved by a torque fluctuation in the first axial direction X1 and in the second axial direction X2, sliding of the first spring 6 with respect to an inner surface of the housing space S1 is lubricated. Sliding of the second spring 7 with respect to an inner surface of the housing space S2 is also lubricated. Further, sliding of the intermediate member 4 with respect to each of the first supporting member 8, the second supporting member 9, the inner member 3, and the outer member 5 is lubricated. Oil supplied to the housing space SS is discharged outside the housing space SS through a clearance provided between the first supporting member 8 and the outer member 5 (refer to the hollow arrow A1). The oil supplied to the housing space SS is discharged outside the housing space SS through a clearance provided between the second supporting member 9 and the outer member 5 (refer to the hollow arrow A2).
Further, a decrease in viscosity of the oil supplied to the housing space S1 that houses the first spring 6 improves a damping effect to absorb a torque fluctuation. A decrease in viscosity of the oil supplied to the housing space S2 that houses the second spring 7 improves a damping effect to absorb a torque fluctuation.
According to this structural arrangement, the intermediate member 4 is linked with the torque transmission shaft TT through the first helical spline coupling HC1 and linked with the outer member 5 through the second helical spline coupling HC2. When a torque fluctuation occurs in the torque transmission path, due to actions of the first helical spline coupling HC1 and the second helical spline coupling HC2, the intermediate member 4 is moved in the second axial direction X2 in resistance to the first spring 6 or moved in the first axial direction X1 in resistance to the second spring 7. Therefore, it is possible to absorb a bidirectional torque fluctuation in the auxiliary machine-equipped engine 120H.
In the preferred examples so far described, although not shown, the first outer helical spline may be located on the outer circumference 2a of the base 2 or may be located on the outer circumference of the torque transmission shaft TT. Further, the torque fluctuation absorber TFA may be provided around at least one torque transmission shaft TT. Further, the first spring 6 and the second spring 7 may have an equal spring constant to each other, or the first spring 6 may have a smaller spring constant than the second spring 7. Further, the oil path L in the preferred modified example of
In the above-described preferred embodiments, an example which includes a jet pump is cited as the vessel propulsion apparatus. However, preferred embodiments of the present invention are applicable to other modes of vessel propulsion apparatuses such as outboard motors, inboard/outboard motors (stern drive, inboard motor/outboard drive), inboard motors, etc. Various features so far described may be used in combination whenever appropriate.
While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-194872 | Nov 2021 | JP | national |
