JP6302244B2 - Propulsion shaft damper - Google Patents

Description

  The present invention relates to a propulsion shaft damper mounted on a propulsion shaft such as a propeller shaft of an outboard motor in a small boat, a propeller shaft of an automobile, or a drive shaft of a motorcycle.

  For example, in an outboard motor attached to the stern part of a small vessel, a bush-like damper called a propeller damper is interposed between the propeller boss and the propeller shaft.

  As shown in FIG. 9, this type of propeller damper 100 includes a sleeve 110 coupled to a propeller shaft (not shown) by a spline 111, and a rubber-like elasticity integrally formed on the outer periphery thereof and engaged with a torque transmission member of the propeller boss. The elastic body 120 is made of a material (rubber material or synthetic resin material having rubber-like elasticity). The elastic body 120 extends in the axial direction and has a circumferential thickness relatively at the axial end 121a. A large number of elastic ribs 121 which are largely reduced at the other end 121b are formed at predetermined intervals in the circumferential direction.

  As shown in FIG. 10, the propeller damper 100 is configured so that the elastic ribs 121 come into contact with the torque transmission ribs 200 provided on the propeller boss side at circumferential intervals corresponding to the elastic ribs 121, as shown in FIG. 10. Is transmitted to the propeller, and the elastic deformation of the elastic rib 121 absorbs torque fluctuations such as shock input. In addition, as a typical prior art of this type of propeller damper, there are the following patent documents.

JP 2008-215445 A

  This type of propeller damper 100 is required to have not only a torque transmission function but also a shock reduction function such as an impact sound during gear change. Each function is largely based on feeling. When the torque is less than a predetermined value, the spring constant is lowered to reduce the impact, and when the torque is higher than the predetermined value, the spring constant is increased to ensure the torque transmission force. Thus, it is effective to set the spring constant to a two-stage characteristic.

  However, according to the conventional structure, as shown in FIG. 10, from the initial torque input state in which the elastic rib 121 is in contact with the torque transmission rib 200 only on the axial end 121a side where the circumferential thickness is large, as the torque increases. Since the pressure contact region expands toward the other end 121b in the axial direction, as shown in FIG. 11, the circumferential relative displacement amount (the deformation amount of the elastic rib 121) of the elastic rib 121 and the torque transmission rib 200 with respect to the torque is Since it changes linearly, that is, the spring constant k is substantially constant, it is difficult to realize the two-stage characteristics by adjusting the shape of the elastic rib 121 and the hardness of the rubber-like elastic material.

  The present invention has been made in view of the above points, and its technical problem is to reduce the shock by lowering the spring constant when the torque is lower than a predetermined value, and to reduce the spring constant when the torque is higher than the predetermined value. The object is to provide a propeller damper such as a propeller damper that achieves a two-stage characteristic, such as ensuring a torque transmission force by increasing it.

As a means for effectively solving the technical problem described above, the propulsion shaft damper according to the invention of claim 1 includes a sleeve attached to one of the torque input side and the torque output side, and a rubber-like elastic on the outer periphery thereof. A first elastic protrusion and a second elastic protrusion , which are integrally formed of materials and separated from each other in the axial direction, and a surface facing the torque transmission rib of the first elastic protrusion and the second elastic protrusion is the first elastic protrusion. It is inclined as relative circumferential wall thickness of these first elastic projection and second elastic protrusions increases an elastic protrusion side, the first elastic protrusions and the second elastic protrusion, the torque input And the torque transmission rib provided on the other of the torque output side and the torque transmission rib can be contacted in the circumferential direction, and the first elastic projection is preceded by the second elastic projection and the torque transmission rib in a torque increasing process. What is contacted A. The rubber-like elastic material is a rubber material or a synthetic resin material having rubber-like elasticity.

  The propulsion shaft damper having the above-described configuration is interposed between the torque input side and the torque output side and transmits torque. In normal rotation, only the first elastic protrusions are brought into contact with the torque transmission rib, so that the circumferential spring constant is kept low, so that a shock due to a gear change or the like can be absorbed effectively. Further, when the transmission torque between the torque input side and the torque output side increases to a predetermined value or more, the second elastic projection comes into contact with the torque transmission rib due to the increase in the deformation amount of the first elastic projection, that is, the first elastic projection. Since the torque is transmitted by both the second elastic projection and the circumferential elastic constant, the circumferential spring constant is increased, and the torque transmission force is increased.

  According to the above configuration, the contact region of the first elastic protrusion or the second elastic protrusion with respect to the torque transmission rib is relatively reduced in the circumferential thickness of the first elastic protrusion or the second elastic protrusion due to an increase in the transmission torque. Since it expands to the side, a non-linear rise in the spring constant can be suppressed.

Promotion shaft damper according to the invention of claim 2 is the structure of claim 1, radially rising angle of the facing surfaces of the torque transmission rib first elastic projection and second elastic projection, second elastic projections It will be relatively gentle on the side.

  According to the above configuration, the contact area of the first elastic protrusion or the second elastic protrusion with respect to the torque transmission rib due to the increase of the transmission torque is relatively the surface of the surface facing the torque transmission rib of the first elastic protrusion or the second elastic protrusion. Since the radial rise angle is gradually increased, the non-linear increase in the spring constant can be suppressed.

  According to the propulsion shaft damper according to the present invention, in the normal rotation where the transmission torque between the torque input side and the torque output side is small, only the first elastic protrusion comes into contact with the torque transmission rib, thereby causing a circumferential spring constant. Therefore, when the transmission torque increases more than a predetermined value, both the first elastic protrusion and the second elastic protrusion come into contact with the torque transmission rib. A two-stage characteristic such that the circumferential spring constant increases and the torque transmission force increases can be realized.

It is a perspective view showing a first embodiment of a propulsion shaft damper according to the present invention. It is explanatory drawing which shows the effect | action by 1st embodiment. It is a diagram which shows the spring characteristic by 1st embodiment. It is a perspective view which shows 2nd embodiment of the damper for propulsion shafts which concerns on this invention. It is a diagram which shows the spring characteristic by 2nd embodiment. It is a perspective view which shows 3rd embodiment of the damper for propulsion shafts which concerns on this invention. It is explanatory drawing which shows the effect | action by 3rd embodiment. It is a diagram which shows the spring characteristic by 3rd embodiment. It is a perspective view which shows an example of the damper for propulsion shafts which concerns on a prior art. It is explanatory drawing which shows the effect | action by the damper for propulsion shafts which concerns on a prior art. It is a diagram which shows the spring characteristic by the damper for propulsion shafts which concerns on a prior art.

  Hereinafter, preferred embodiments of a propulsion shaft damper according to the present invention will be described with reference to the drawings. First, FIG. 1 and FIG. 2 show a first embodiment.

That is, in the first embodiment, the propulsion shaft damper according to the present invention is, for example, a propeller damper 1 interposed between a propeller shaft of an outboard motor propelling a small vessel and a torque transmission sleeve of propeller boss. The propeller damper 1 is applied to a sleeve 10 and an elastic body 20 provided integrally on the outer periphery thereof. Incidentally, in this embodiment, propeller shaft corresponds to torque input side, the propeller boss is equivalent to torque output side.

  The sleeve 10 has a cylindrical shape made of metal or the like, and a spline 11 is formed on the inner peripheral surface thereof. The spline 11 is fitted to a spline formed on the outer peripheral surface of a propeller shaft (not shown). It is to be mounted in a state that has been made.

  The elastic body 20 is formed by integrally vulcanizing and bonding together with a rubber-like elastic material on the outer periphery of the intermediate portion in the axial direction of the sleeve 10, and an annular groove 23 extending in the circumferential direction at the central portion in the axial direction. The first elastic projection 21 and the second elastic projection 22 separated from each other by the axial direction, and the outer peripheral surface of the sleeve 10 extending from the inner diameter portion of the first elastic projection 21 and the second elastic projection 22 to both sides in the axial direction. And a tubular membrane portion 24 vulcanized and bonded so as to cover.

  Specifically, the first elastic protrusions 21 are provided at equal intervals in the circumferential direction, and a first engagement groove 25 extending in the axial direction is formed between the first elastic protrusions 21 and 21 adjacent in the circumferential direction. ing. Further, the second elastic protrusions 22 are provided at circumferential positions at equal intervals in the circumferential direction and corresponding to the first elastic protrusions 21, and between the second elastic protrusions 22, 22 adjacent in the circumferential direction, The second engaging grooves 26 extend in the axial direction. The annular groove 23 between the first elastic protrusion 21 and the second elastic protrusion 22 is a second engagement groove 25 between the first elastic protrusions 21, 21 and a second groove between the second elastic protrusions 22, 22. It is formed deeper than the engaging groove 26.

  As shown in FIG. 2, side surfaces on both sides in the circumferential direction of the first elastic protrusions 21 (which can also be referred to as inner surfaces of the first engagement grooves 25) 21a are first elastic toward the second elastic protrusions 22 side. It is inclined with respect to the axial direction so that the circumferential thickness t1 of the protrusion 21 decreases, that is, the groove width of the first engagement groove 25 increases toward the second engagement groove 26 side. Similarly, the side surfaces 22a on both sides in the circumferential direction of the second elastic protrusions 22 (also referred to as inner surfaces of the second engagement grooves 26) 22a are similarly directed to the second elastic protrusions 22 toward the side opposite to the first elastic protrusions 21. Is inclined with respect to the axial direction so that the circumferential thickness t2 thereof decreases, that is, the groove width of the second engagement groove 26 becomes wider toward the opposite side of the first engagement groove 25. . Further, the side surfaces 21a and 22a are formed so that their extended surfaces are the same.

  As shown in FIG. 1, the radial height of the first elastic protrusion 21 is slightly higher than the radial height of the second elastic protrusion 22, and the outer peripheral surface of the first elastic protrusion 21 and the outer periphery of the second elastic protrusion 22. The surfaces are formed such that their extended surfaces are the same conical surface.

As shown in FIG. 2, the first engagement groove 25 and the second engagement groove 26 that are adjacent to each other in the axial direction have a torque transmission rib 2 provided on the torque transmission sleeve of the propeller boss across both of them. In other words, the side surface 21a of the first elastic protrusion 21 and the side surface 22a of the second elastic protrusion 22 can contact the torque transmission rib 2 in the circumferential direction. Incidentally, the side surface 21a, 22a is equivalent to a surface facing the torque transmission rib.

  The torque transmission rib 2 extends in the axial direction and has a circumferential width that is equally formed over the entire length, and corresponds to the first engagement groove 25 and the second engagement groove 26 of the elastic body 20. It is formed at intervals. Therefore, in the process in which the propeller shaft and the propeller boss are displaced relative to each other in the circumferential direction due to torque fluctuation, the side surface 21a of the first elastic protrusion 21 having a large thickness in the circumferential direction precedes the second elastic protrusion 22 and the torque transmission rib 2. The side surface 21a of the first elastic protrusion 21 is in contact with the torque transmission rib 2 in a portion near the end 21b having a large circumferential thickness t1 preceding the portion near the end 21c on the opposite side. When the torque increases to a predetermined value or more, the side surface 22a of the second elastic protrusion 22 also has a portion near the end 22b having a large circumferential thickness t2 preceding a portion near the opposite end 22c. Thus, the torque transmission rib 2 is brought into contact.

  The propeller damper 1 configured as described above is mounted in a state in which the sleeve 10 is fitted to the spline of the propeller shaft of the outboard motor in the spline 11 formed on the inner peripheral surface thereof, and the elastic body 20. Is inserted into the inner peripheral surface of the propeller boss sleeve to elastically couple the propeller shaft and the propeller boss.

  For this reason, when the engine of the outboard motor is driven, the driving torque of the propeller shaft is transmitted to the propeller boss through the propeller damper 1. At that time, the elastic body 20 effectively absorbs the impact (shift shock) when the shift is changed from neutral to forward (or reverse) and the vibration from the outer peripheral rotor blades of the propeller boss.

  Specifically, during normal rotation, one side surface 21a of the first elastic protrusion 21 of the elastic body 20 is in contact with the torque transmission rib 2 with a portion near the end portion 21b having a large circumferential thickness t1 leading. Since the side surface 21a of the first elastic protrusion 21 is inclined with respect to the axial direction (relative to the torque transmission rib 2), the side surface 21a of the first elastic protrusion 21 with respect to the torque transmission rib 2 is increased as the torque increases. Is gradually expanded toward the side where the circumferential thickness t1 becomes smaller. For this reason, the volume increase of the part which receives a deformation | transformation with the increase in torque is suppressed, and as shown in FIG. 3, the nonlinear rise of the spring constant k1 is suppressed and it is hold | maintained at a low spring state.

  In addition, the axial length and radial thickness of the elastic body 20, the inclination angles of the side surfaces 21a and 22a of the first elastic protrusion 21 and the second elastic protrusion 22, etc., for example, the propeller damper of FIG. When the length of 100 elastic bodies 120 in the axial direction, the radial thickness, the inclination angle of the side surface of the elastic protrusion 121 are the same, the axial length of the first elastic protrusion 21 is shorter than the elastic protrusion 121 of FIG. Therefore, the spring constant k1 by the first elastic protrusion 21 is lower than the spring constant k by the elastic protrusion 121 in FIG. As a result, the shock-absorbing property is improved, and the shift shock at the time of gear change and the impact sound caused by the shock can be effectively reduced.

  If the torque further increases after the entire axial direction of the side surface 21a of the first elastic protrusion 21 comes into contact with the torque transmission rib 2 due to the increase in torque, the second elasticity is reached when this torque becomes a predetermined value or more. Since the side surface 22a of the protrusion 22 is also in contact with the torque transmission rib 2 and torque is transmitted by both the first elastic protrusion 21 and the second elastic protrusion 22, the spring constant k2 is increased as shown in FIG. Power increases. Further, since the side surface 22a of the second elastic protrusion 22 is also inclined with respect to the axial direction (relative to the torque transmission rib 2), a portion near the end portion 22b having a large circumferential thickness t2 is preceded first. Contact with the torque transmission rib 2, and the contact area expands toward the side where the circumferential thickness t2 becomes relatively smaller as the torque increases, so that the spring constant k2 is increased linearly and rapidly. Can do.

  Therefore, according to the propeller damper 1, in the normal rotation with a small torque, only the first elastic projection 21 comes into contact with the torque transmission rib 2 so that the spring constant k1 is low. When the torque increases more than a predetermined value, both the first elastic protrusion 21 and the second elastic protrusion 22 are brought into contact with the torque transmission rib 2 to make a transition to the high spring constant k2. Two-stage characteristics such as ensuring torque transmission force can be realized.

  Next, FIG. 4 shows a second embodiment in which the propulsion shaft damper according to the present invention is applied as a propeller damper 1 of an outboard motor.

  In the second embodiment, the difference from the first embodiment described above is that the annular groove 23 is unevenly distributed on the second elastic protrusion 22 side from the axial center portion of the elastic body 20, That is, the first elastic protrusion 21 is longer than the second elastic protrusion 22.

  According to the above configuration, the axial length and the radial thickness of the elastic body 20, the inclination angles of the side surfaces 21 a and 22 a of the first elastic protrusion 21 and the second elastic protrusion 22, etc. When the specification is the same as that of the embodiment, as shown in FIG. 5, the spring constant k 1 ′ by the first elastic protrusion 21 is changed to the spring constant by the contact of both the first elastic protrusion 21 and the second elastic protrusion 22. The transition point P ′ to k2 ′ moves to a higher torque value than the transition point P from the spring constant k1 to k2 in the first embodiment.

  Further, since the axial length of the first elastic protrusion 21 is longer than that in the first embodiment, the spring constant k1 ′ is higher than the spring constant k1 in the first embodiment, whereas Since the axial length of the second elastic protrusion 22 is shorter than that of the first embodiment, the increase in torque transmission force due to the spring constant k2 ′ is made smaller than the spring constant k2 of the first embodiment. be able to.

  That is, according to the present invention, the spring characteristics can be appropriately tuned as required by changing the separation position of the first elastic protrusion 21 and the second elastic protrusion 22 by the annular groove 23 in the elastic body 20. it can.

  Next, FIGS. 6 and 7 show a third embodiment in which the propulsion shaft damper according to the present invention is applied as a propeller damper 1 of an outboard motor.

  In the propeller damper 1 according to the third embodiment, the difference from the first embodiment described above is that the side surfaces (first engagement grooves) of the elastic body 20 on both sides in the circumferential direction of the first elastic protrusion 21. 25a (which can also be referred to as the inner side surface of 25), and the side surfaces on both sides in the circumferential direction of the circumferential side surfaces 22a of the second elastic protrusions 22 (also referred to as the inner side surface of the first engaging groove 26) 22a. In shape.

  Specifically, the inclination angles of the side surfaces 21a and 22a of the first elastic protrusion 21 and the second elastic protrusion 22 with respect to the axial direction are the side surfaces 21a and 22a of the first elastic protrusion 21 and the second elastic protrusion 22 in the first embodiment. The rising angle of the side surfaces 21a, 22a from the bottoms of the first engagement groove 25 and the second engagement groove 26 is larger than the inclination angle of the second elastic protrusion 22 from the end 21b of the first elastic protrusion 21. It is formed so as to become gradually gentle toward the end 22c. Even in this embodiment, the side surfaces 21a on both sides in the circumferential direction of the first elastic projection 21 and the side surfaces 22a on both sides in the circumferential direction of the second elastic projection 22 are formed so that their extension surfaces are the same. .

  According to the above configuration, in the same manner as in the first embodiment, among the one side surface 21a of the first elastic protrusion 21 in the elastic body 20, the vicinity of the end portion 21b having the large circumferential thickness t1 is the torque transmission rib 2. In the normal rotation state in contact, as the torque increases, the contact area of the side surface 21a of the first elastic protrusion 21 with respect to the torque transmission rib 2 expands to the side where the circumferential thickness t1 becomes relatively small. go. For this reason, since the volume increase of the part which receives a deformation | transformation with the increase in a torque is suppressed, as shown in FIG. 8, the nonlinear rise of the spring constant k1 "by the 1st elastic protrusion 21 is suppressed, and a low spring state Retained.

  In addition, the inclination angle of the side surface 21a of the first elastic protrusion 21 is large, and the rising angle of the side surface 21a from the groove bottom of the first engagement groove 25 gradually decreases toward the second elastic protrusion 22 side. , The increase in the volume of the portion that undergoes deformation as the torque increases is suppressed. Therefore, as shown in FIG. 8, the circumferential spring constant k1 ″ by the first elastic protrusion 21 is the same as that of the first embodiment. It is held in a lower spring state than the circumferential spring constant k1 by the one elastic protrusion 21. Therefore, a shift shock at the time of a gear change or the like and an impact sound caused thereby can be further alleviated.

  Further, when the torque further increases after the entire axial direction of the side surface 21a of the first elastic protrusion 21 is brought into pressure contact with the torque transmission rib 2 due to the increase in torque, the second elasticity is reached when the torque becomes a predetermined value or more. The side surface 22 a of the protrusion 22 is also in contact with the torque transmission rib 2. For this reason, torque transmission is performed by both the first elastic protrusion 21 and the second elastic protrusion 22, so that the circumferential spring constant is increased and the torque transmission force is increased as indicated by k 2 ″ in FIG.

  In this case as well, since the inclination angle of the side surface 22a of the second elastic protrusion 22 is large and the rising angle of the side surface 22a from the groove bottom of the second engagement groove 26 becomes gradually gentle, first, the circumferential thickness is increased. In the process of expanding the contact region from the vicinity of the end 22b where t2 is large toward the side where the circumferential thickness t2 is relatively small, an increase in volume of the portion subjected to deformation by the torque transmission rib 2 is suppressed. Therefore, as shown in FIG. 8, the rise of the circumferential spring constant k2 ″ by the second elastic protrusion 22 may be more gradual than the circumferential spring constant k2 of the first embodiment. it can.

  That is, according to the present invention, the spring characteristics can be appropriately set according to demand by changing the inclination angle and the rising angle of the side surfaces 21a and 22a of the first elastic protrusion 21 and the second elastic protrusion 22 in the elastic body 20 with respect to the axial direction. Can be tuned to.

  In the above-described embodiments, the torque is described as being input from the inner peripheral propeller shaft to the sleeve 10 and transmitted to the torque transmission rib 2 via the elastic body 20, but in the opposite case, that is, Even when torque is input from the torque transmission rib 2 to the elastic body 20 and transmitted from the sleeve 10 to the inner peripheral shaft, the present invention can be similarly implemented. The present invention can also be applied to a propulsion shaft damper other than a propeller damper for a small vessel.

  In the illustrated example, the spline 11 is formed on the inner peripheral surface of the sleeve 10 as a means for preventing rotation with the mating shaft. However, other means for preventing rotation such as a key groove and a key are also applicable. .

  Moreover, the outer peripheral surface of the 1st elastic protrusion 21 and the 2nd elastic protrusion 22 may be formed so that the extension surface may become the mutually same cylindrical surface.

1 Propeller damper (propulsion shaft damper)
2 Torque transmission rib 10 Sleeve 20 Elastic body 21 First elastic protrusion 21a Side surface (opposite surface to torque transmission rib)
22 2nd elastic protrusion 22a Side surface (opposite surface with a torque transmission rib)
23 annular groove 25 first engagement groove 26 second engagement groove

Claims (2)

Comprising a sleeve attached to one of the torque input side and the torque output side, and a first elastic projection and second elastic protrusions separated axially from each other is provided integrally with a rubber-like elastic material on the outer periphery thereof, said first The circumferential surface thickness of the first elastic protrusion and the second elastic protrusion is relatively increased on the surface of the first elastic protrusion and the second elastic protrusion facing the torque transmission rib. It is inclined, the first elastic protrusions and the second elastic protrusions, a contactable to said torque input and torque transmission rib provided on the other of the torque output side and circumferential directions, the torque increase The propulsion shaft damper, wherein the first elastic protrusion is brought into contact with the torque transmission rib prior to the second elastic protrusion in the process. 2. The propulsion shaft according to claim 1, wherein a radial rising angle of a surface of the first elastic protrusion and the second elastic protrusion facing the torque transmission rib is relatively gentle on the second elastic protrusion side. damper.

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