JP5901406B2 - Tensioner - Google Patents

Description

The present invention relates to a mechanical tensioner that applies tension to a wound transmission body.
The winding transmission is, for example, a chain, and is used as a timing chain for driving a camshaft or the like in an engine.

Conventionally, a mechanical tensioner includes a pressing member that presses a movable guide that guides a wound transmission body (e.g., a chain) that is running around a plurality of rotating wheels (e.g., sprockets), And an urging unit that causes the urging force to advance the pressing member that moves forward and backward with respect to the winding transmission member to the pressing member (for example, see Patent Document 1).
Note that the mechanical tensioner is a tensioner in which a hydraulic chamber that accommodates pressure oil that applies hydraulic pressure to the pressing member is not formed, that is, a non-hydraulic tensioner, unlike a known hydraulic tensioner.
In addition, a mechanism for applying tension to the winding transmission element acts on the tension wheel to advance the tension wheel that rotates when the winding transmission is wound and the tension wheel that moves forward and backward. There is also known one provided with an urging means for causing it (see, for example, Patent Documents 2 and 3).

JP 2009-257455 A (paragraphs 0025 to 0028, FIGS. 1 to 4) JP-A-10-311392 (paragraphs 0002, 0006 to 0012, FIGS. 1 to 3) Japanese Utility Model Publication No. 64-1469 (column 4, line 29 to column 5, line 14, FIG. 2)

  When the chain, which is a winding transmission, is used for an engine, for example, and is wound around a plurality of sprockets that are driven by a crankshaft that is driven to rotate by the torque generated by the engine, the torque fluctuations As a result of crank shaft rotation fluctuations caused by fluctuations in the load acting on the crankshaft as an output shaft, fluctuations in tension occur in the chain. On the other hand, the tension of the chain acts on the pressing member of the tensioner or the tension wheel as a reaction force from the chain.

For this reason, the pressing member or the tension wheel performs forward and backward movements that move forward and backward according to a force (hereinafter referred to as “load”) including the urging force of the urging means and the reaction force of the chain. The fluctuation of the tension, that is, the fluctuation of the reaction force causes the load acting on the pressing member or the tension wheel to fluctuate to generate a vibration that repeats forward and backward movement on the pressing member or the tension wheel. There was a problem of generating noise due to contact between members.
On the other hand, in a hydraulic tensioner that uses pressure oil in the hydraulic chamber to suppress vibration of the pressing member or tension wheel, a pressure oil supply passage for the tensioner is required, and the amount of pressure oil used increases. In addition, since the capacity of the pressure oil supply source (for example, oil pump) may need to be increased, there is a problem that the cost associated with the installation of the tensioner increases.

  The present invention solves such a problem, and an object of the present invention is to reduce the tension wheel vibration generated by the application of a fluctuating load based on the fluctuation of the reaction force from the wound transmission body. It is to provide a tensioner that is suppressed by a mechanical structure using the moment of inertia, thereby reducing noise caused by vibration of the tension wheel, reducing the size, and reducing the installation cost.

The invention according to claim 1, and a tension wheel which is movably supported on the base for rotation hooked belt-driven body wound that running is passed around a plurality of rotating wheels, the tension wheel A support member rotatably supported; and an urging means for applying an urging force for advancing the tension wheel that moves forward and backward to the tension wheel. The tension wheel is attached to the winding transmission body. In a tensioner that can be moved forward by the urging force to apply tension and can be moved back by a reaction force from the winding transmission body, a rotary mass body that is rotatably supported by the base, and an advance of the tension wheel . A motion conversion mechanism for converting a retreating motion into a rotational motion of the rotating mass body, the rotating mass body having its inertia moment Configure the inertial resistance against the forward and backward movement of the tension wheel by the motion converting mechanism comprises a rotary part which is rotated by reciprocating movement of the tension wheel, the support member is in the motion conversion mechanism, the rotating part or by members der Rukoto which rotates the rotating part integral is obtained by solving the problems described above.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, the motion conversion mechanism includes a rolling element that is the rotating component and a guide that causes the rolling element to roll by advancing and retracting the tension wheel. And the guide body solves the above-described problem by guiding the tension wheel through the rolling body so that the rolling body performs the forward and backward movement together with the tension wheel. .

According to a third aspect of the present invention, in addition to the configuration of the second aspect of the invention, the biasing means also serves as a motion converting biasing means that presses the rolling element against the guide body. It has been solved.

The invention according to claim 4, in addition to the configuration of the invention according to claims 1 to any one of claims 3, wherein the rotating component is the rotating part with respect to the amount of movement of the tension wheel in the forward and backward motion The above-mentioned problem is solved by defining an amount of rotation and having an effective radius centered on the rotation axis of the rotating component, and the effective radius being smaller than the maximum radius of the rotating mass body.

According to a fifth aspect of the present invention, in addition to the configuration according to any one of the first to fourth aspects, the support member is the rotating mass body, and the tension wheel is the rotating mass body. The above-mentioned problem is solved by being supported on the outer periphery of the lens.

Accordingly, the tensioner of the present invention, a tension wheel which is movably supported on the base for rotation is wound around belt-driven body running is stretched in a plurality of rotating wheels, the tension wheel A support member that rotatably supports and an urging means that applies an urging force that moves forward and backward the tension wheel that moves forward and backward to the tension wheel, and the tension wheel applies tension to the wound transmission body. Therefore, the tension wheel on which the winding transmission member is wound can be moved forward by the biasing force and can be moved back by the reaction force from the winding transmission member. It moves forward and backward according to the force including the reaction force from the body, that is, the load, and moves forward when the tension of the wound transmission body decreases to apply tension. Because it reduces the tension retracts when increasing tension, the tensioner by, not only the tension of the belt-driven body can be set appropriate size, an effect unique to the present invention as follows.

That is, according to the tensioner of the present invention according to claim 1, the rotary mass body rotatably supported on the base and the motion conversion mechanism for converting the forward / backward movement of the tension wheel into the rotary motion of the rotary mass body are provided . The rolling mass constitutes an inertial resistance against the forward and backward movement of the tension wheel by its inertia moment , the motion conversion mechanism includes a rotating part that rotates by the forward and backward movement of the tension wheel, and the support member rotates in the motion conversion mechanism. the parts or members der Rukoto which rotates the rotating part integral with the load varies with the tension fluctuation of the belt-driven body (hereinafter, referred to as "fluctuating load".) when acting on the tension wheel, the tension wheel The motion conversion mechanism is linked to the rotating mass body so that the forward / backward movement is converted into the rotational motion of the rotating mass body. Therefore, the moment of inertia of the rotating mass body becomes resistance to the rotational motion of the rotating mass body due to the variable load, and the tension wheel is restrained from moving forward and backward due to the variable load. Is suppressed, and noise generated by the contact between the constituent members of the tensioner due to the vibration is reduced. And as the frequency of fluctuation of the fluctuating load increases, the effect of suppressing the vibration of the tension wheel by the rotating mass body is enhanced, so that the noise reduction effect of the tensioner is also enhanced. On the other hand, when the fluctuation of the load is slow and the fluctuation frequency of the variable load is low, the tension wheel slowly moves forward and backward, so that the resistance due to the moment of inertia with respect to the rotational motion of the rotating mass body is reduced. By gradually moving forward or backward, the tension of the winding transmission can be set to an appropriate magnitude by the tensioner.
In addition, in a structure in which the vibration of the tension wheel that is subject to fluctuating loads is suppressed by inertial resistance, the inertial moment that can be set to a value larger than the mass of the rotating mass body is used. The tensioner can be reduced in size while improving the effect.
In addition, since vibration of the tension wheel due to load fluctuation is suppressed without using pressure oil, it is not necessary to increase the pressure oil supply passage for the tensioner, increase the amount of pressure oil used, and increase the capacity of the pressure oil supply source. Therefore, the cost for installing the tensioner can be reduced.
Further, since the tension wheel is rotatably supported by the motion conversion mechanism or the rotary mass body using the motion conversion mechanism or the rotary mass body, a dedicated support member for rotatably supporting the tension wheel is provided. Since the number of parts is reduced as compared with the case, the tensioner can be reduced in size and the cost thereof can be reduced.

In addition , since the motion conversion mechanism includes a rotating part that rotates by the advancement and retraction of the tension wheel, the inertial moment of the rotating part in addition to the inertial moment of the rotating mass body causes the tension wheel to advance and retract according to the fluctuating load. Therefore, it is possible to further suppress the vibration of the tension wheel caused by the fluctuating load due to the inertia moment of the rotating parts, or the inertia of the rotating mass body in consideration of the increase of the inertia moment of the rotating parts. By reducing the moment, the rotating mass body can be reduced in size, and the tensioner can be reduced in size.
Furthermore, in the motion conversion mechanism, the support member is a rotating component or a member that rotates integrally with the rotating component, so that the tension wheel rotates integrally with the rotating component and the rotating component that are components of the motion converting mechanism. Since the tension wheel is rotatably supported by using, the number of parts of the tensioner can be reduced, the tensioner can be downsized, and the cost thereof can be reduced.

According to the tensioner of the present invention according to claim 2 , in addition to the effect of the invention according to claim 1 , the motion conversion mechanism rolls the rolling element by a rolling element that is a rotating part and a forward and backward movement of a tension wheel. A guide body for rotating the rolling body that rotationally drives the rotating mass body by guiding the tension wheel through the rolling body so that the rolling body moves forward and backward together with the tension wheel. Since the guide body for rolling the rolling element guides the tension wheel to advance and retreat through the rolling element, the advancing and retreating movement of the tension wheel is reliably transmitted to the rolling element, and further, by the motion conversion mechanism. The certainty of the conversion from the advancing / retracting motion to the rotating motion is improved, and the stability of the vibration suppression effect of the tension wheel by the rotating mass body can be improved.
In addition, since the advancement / retraction movement of the tension wheel is performed via a rolling element that is in rolling contact with the guide body, the friction when the tension wheel moves forward / backward with respect to the guide body becomes rolling friction. As compared with the case of sliding with respect to, the frictional force between the guide body and the tension wheel can be reduced, and the smoothness of the forward and backward movement of the tension wheel can be improved.

According to the tensioner of the present invention according to claim 3, in addition to the effects of the invention according to claim 2, the biasing means, by serving as a motion converting biasing means for rolling pressing the element into the guide body, with The urging means urges the rolling wheel against the guide body at the same time as urging the tension wheel. Therefore, the number of parts of the tensioner can be reduced, and the cost can be reduced. By improving the certainty of the conversion to, the stability of the vibration suppression effect of the tension wheel by the rotating mass body can be improved.

According to the tensioner of the present invention according to claim 4 , in addition to the effect exhibited by the invention according to any one of claims 1 to 3 , the rotating component rotates with respect to the amount of movement of the tension wheel in the forward / backward movement. By defining the amount of rotation of the part and having an effective radius centered on the axis of rotation of the rotating part, the effective radius is smaller than the maximum radius of the rotating mass body, so that the effective radius is a unit by the forward and backward movement of the tension wheel. Since the amount of rotation (rotation angle) of the rotating parts per movement amount, and hence the amount of rotation (rotation angle) of the rotating mass body, is defined, the rotating mass body with respect to the fluctuating load fluctuating frequency by changing the effective radius The characteristics of the rotational resistance can be adjusted. Since the effective radius is smaller than the maximum radius of the rotating mass body, the same effect as when the moment of inertia of the rotating mass body is increased can be obtained without increasing the size of the rotating mass body. The tensioner can be downsized while enhancing the vibration suppression effect of the tension wheel.

According to the tensioner of the present invention according to claim 5 , in addition to the effect exerted by the invention according to any one of claims 1 to 4 , the support member is a rotating mass body, and the tension wheel is rotated. By being supported on the outer periphery of the mass body, the tension wheel and the rotary mass body are arranged at the same position in the axial direction parallel to the rotational axis, so that the tensioner can be reduced in size in the axial direction, and the rotational mass can be reduced. Since the body also serves as a support member that rotatably supports the tension wheel, the weight can be reduced.

The front view of the timing chain transmission apparatus which shows the Example of this invention and is equipped with a tensioner. The principal part enlarged view centering on the tensioner of FIG. FIG. 3 is a main part sectional view taken along line III-III in FIG. 1. The figure which shows 2nd Example of this invention and corresponds to FIG. FIG. 7 shows a third embodiment of the present invention and is a view corresponding to FIG. FIG. 6 is a view corresponding to FIG. 3 in the third embodiment of FIG.

Tensioner of the present invention, a tension wheel which is movably supported on the base for rotation hooked belt-driven body wound that running is passed around a plurality of rotary wheels, rotatably this tension wheel And a biasing means for applying a biasing force to the tension wheel that causes the tension wheel to move forward and backward, and the tension wheel is attached to apply tension to the wound transmission body. is advanceable by force conversion, the tensioner is retractable by the reaction force from the belt-driven member, a rotating mass that is rotatably supported on the base, the advance withdrawal movement of the tension wheel rotary motion of the rotating masses A rotating mass body with respect to the forward and backward movement of the tension wheel by its inertia moment Configure the inertial resistance, motion converting mechanism comprises a rotary part which is rotated by reciprocating movement of the tension wheel, the support member, the motion converting mechanism, Ru member der rotating integrally with the rotating component or the rotating component Thus, the tension wheel vibration generated by the application of a fluctuating load based on the fluctuation of the reaction force from the wound transmission body is suppressed by the mechanical structure using the inertial moment of the rotating mass body. As long as the noise caused by the vibration of the wheel is reduced, the size is reduced, and the installation cost is reduced, the specific mode may be any.

For example, the winding transmission to which tension is applied by the tensioner of the present invention is a chain wound around a sprocket as a rotating wheel, or something other than a chain (for example, a belt wound around a pulley as a rotating wheel). is there. The tension wheel of the tensioner of the present invention is a tension sprocket for a chain and a tension pulley for a belt.
The tensioner of the present invention is provided in a winding transmission for timing or other than timing. The machine provided with the winding transmission device is an engine for automobiles or engines other than automobiles, or a machine other than engines (for example, industrial machines).

Embodiments of the present invention will be described below with reference to FIGS.
1 to 3 are diagrams for explaining a first embodiment of the present invention.
Referring to FIG. 1, in a first embodiment of the present invention, a tensioner 100 that applies tension (hereinafter referred to as “tension”) to a timing chain 16 as a winding transmission is a mechanical tensioner, and is an engine 1. Is provided in a timing chain transmission device 10 as a winding transmission device.
The engine 1 is a reciprocating four-stroke internal combustion engine mounted on an automobile. The timing chain transmission device 10 rotationally drives cam shafts 4 and 5 included in a valve gear that opens and closes the intake and exhaust valves of the engine 1 in synchronization with the rotation of the crankshaft 3 of the engine 1.

In addition to the tensioner 100, the timing chain transmission 10 includes a plurality of sprockets 13 to 15 that are rotationally driven by the engine 1, and a timing chain 16 that is an endless chain (hereinafter referred to as "chain 16"). And a guide device that guides the chain 16 running over the plurality of sprockets 13 to 15 while being in contact with the chain 16.
In the present embodiment, the plurality of sprockets 13 to 15 are connected to a crankshaft 3 as a drive rotation shaft included in the engine 1 and are driven to rotate by the crankshaft 3. A pair of driven sprockets 14 and 15 as a pair of driven rotating wheels which are respectively coupled to a valve cam shaft 4 and 5 as a pair of driven rotating shafts and driven to rotate by power transmitted by a chain 16. Composed.

Here, the crankshaft 3, the camshafts 4 and 5, and the engine block 2 that rotatably supports the crankshaft 3 and the camshafts 4 and 5 constitute a main body of the engine 1. The main body is an installation portion in the engine 1 where the timing chain transmission device 10 is installed.
The rotation axes L3 to L5 of the sprockets 13 to 15 are parallel to each other and coincide with the rotation axes of the crankshaft 3 and the camshafts 4 and 5, respectively, and define the distance between the rotation axes of the sprockets 13 to 15. .

The guide device includes a tensioner 100 that also serves as a movable guide that guides the chain 16 on its slack side, and a fixed lever 18 that serves as a fixed guide with which the chain 16 slides on its tight side.
The engine 1 generates torque for rotationally driving the crankshaft 3. The tension of the chain 16 fluctuates due to fluctuations in the rotation of the crankshaft 3 caused by periodic fluctuations in the torque and load fluctuations acting on the crankshaft 3. Therefore, the engine 1 that drives the drive sprocket 13 to run the chain 16 is also a drive source that causes the chain 16 to vary in tension.
Due to this variation in tension, the reaction force Fr acting on the tensioner 100 from the chain 16 (see FIG. 2 showing an example of the reaction force Fr) also varies, and the tension sprocket 101 of the tensioner 100 varies in this variation. Reaction force Fr acts. The reaction force Fr is a resultant force of reaction forces acting at a plurality of contact portions between the chain 16 and the tension sprocket 101.

  Referring mainly to FIGS. 2 and 3, and appropriately referring to FIG. 1, the tensioner 100 is a tension sprocket 101 (hereinafter referred to as “sprocket 101”) as a tension wheel around which a traveling chain 16 is wound. )), And a base 102 that movably supports the sprocket 101 so that the sprocket 101 moves forward and backward with respect to the chain 16, and a spring force Fs as an urging force that moves the sprocket 101 forward to the sprocket 101. A spring 103 as an urging means to be actuated, a rotating mass body 104 supported by the base 102 so as to be rotatable about the rotation axis Li, and a motion conversion for converting the advancing and retreating motion of the sprocket 101 into the rotating motion of the rotating mass body 104 A rack and pinion mechanism 110 as a mechanism is provided.

  The base 102 is detachably attached to the engine block 2 with bolts (not shown) as fixing means at the attachment portion 102a. The base 102 is an integrated member that supports the sprocket 101, the rotating mass body 104, and the rack and pinion mechanism 110. As another example, for example, the base 102 is separated from each other to support the sprocket 101 and the rotating mass body 104 separately. For example, it may be composed of a plurality of members separated from each other.

The sprocket 101 and the rotating mass body 104 are disk-like rotating members that are supported by the base 102 via the rack and pinion mechanism 110 so as to be able to move forward and backward and to be rotatable about the rotation axes Lt and Li, respectively. Therefore, the rack and pinion mechanism 110 also serves as a support member that rotatably supports the sprocket 101.
The sprocket 101 can be advanced with respect to the base 102 by the spring force Fs and can be retracted with respect to the base 102 by the reaction force Fr in order to apply tension to the chain 16. Therefore, the sprocket 101 moves forward and backward by a force including the spring force Fs and the reaction force Fr, that is, the load F. In this embodiment, this forward / backward movement is a linear movement.

The rack and pinion mechanism 110 includes a pinion 111 as a rolling element that performs forward / backward movement and rotational movement integrally with the sprocket 101 and the mass rotator 104, and is supported by the base 102 and meshed with the pinion 111 to cause the pinion 111 to move. A rack 112 that is a pinion rotating gear that rotates about the rotation axis Lp and a connecting shaft 113 that connects the pinion 111 and the rotating mass body 104 are provided as constituent members.
The connecting shaft 113 is a member that rotates integrally with the pinion 111 and the rotating mass body 104, and is a support member that supports the sprocket 101 in a rotatable manner and can move forward and backward together with the sprocket 101 with respect to the base 102.
The sprocket 101 is slidably supported on the outer periphery of the connecting shaft 113, but may be supported via a bearing.

The pinion 111, the rotating mass body 104, and the connecting shaft 113 are composed of separate members, and are fixed and integrated with each other so as to rotate integrally around the rotation axis Lp of the pinion 111. Accordingly, the pinion 111, the rotating mass body 104, and the connecting shaft 113 rotate together while sharing the rotation axis Lp. As another example, the pinion 111, the rotating mass body 104, and the connecting shaft 113 may be configured by a single member integrated by integral molding.
For this reason, when the sprocket 101 moves back and forth, the sprocket 101 can rotate around the rotation axes Li and Lp that coincide with the rotation axis Lt, and the rotation axes Li, Lp, and Lt move forward and backward. do.

The pinion 111 is a rotating component that drives and rotates the rotating mass body 104 by being driven and rotated by the sprocket 101 that is moving forward and backward. The pinion 111 is composed of a pair of first and second pinions 111a and 111b arranged with the sprocket 101 sandwiched in an axial direction parallel to the rotation axis Lp.
Each of the pinions 111a and 111b is guided by the rack 112 when the sprocket 101 moves forward and backward, and rotates about the rotation axis Lp parallel to the swing axis L7 while rolling on the rack 112.

The rack 112 is a guide body that guides the pinion 111 to roll while the sprocket 101 moves forward and backward, and guides the pinion 111 to move forward and backward while the pinion 111 rotates. It is a rotation generating member to be made.
In this embodiment, the rack 112 supported by the base 102 is provided in a fixed state on the base 102 by being integrally formed with the base 102. However, as another example, the rack 112 is configured by a member separate from the base 102. It may be fixed to 102 by fixing means.

The rack 112 includes a pair of first and second racks 112a and 112b that mesh with the first and second pinions 111a and 111b, respectively, with the rotating mass body 104 and the sprocket 101 interposed therebetween in the axial direction. Is done.
Since the sprocket 101 is disposed between the first and second pinions 111a and 111b and the first and second racks 112a and 112b, the stability of the forward and backward movement of the sprocket 101 is improved, and the sprocket 101 rotates from the forward and backward movement. The certainty and stability of the conversion to motion can be improved.

Referring to FIG. 2, the rack 112 defines the movement direction A1 of the sprocket 101 in the forward / backward movement, which is a linear movement direction A1 in this embodiment. By changing the acute inclination angle α formed by the specific direction A2 and the moving direction A1 of the sprocket 101, the sprocket can be moved with respect to the unit advance / retreat amount of the central portion 16c of the winding portion 16a of the chain 16 corresponding to the load F. The amount of rotation of the rotating mass body 104 and the rotating mass body 104 can be adjusted.
Here, the winding portion 16a is a portion of the chain 16 that is wound around the sprocket 101, and the central portion 16c is the center of the winding portion 16a in the circumferential direction around the rotation axis Lt. The specific direction A2 is an axis parallel to the rotation axis Lp when the central portion 16c is at a specific position (for example, the position of the central portion 16c when the sprocket 101 occupies the specific position in the movement direction A1). When viewed from the direction, the direction is parallel to a straight line passing through the central portion 16c and the rotation axis Lp, and FIG. 2 shows an example thereof. The forward / backward movement amount of the central portion 16c is the moving distance of the central portion 16c in the specific direction A2 based on the forward / backward movement of the sprocket 101.
Depending on the arrangement of the tensioner 100, the specific direction A2 can be the horizontal direction.

  The rack 112 is arranged so as to be inclined so as to move downward when the sprocket 101 moves forward. As a result, the weights of the sprocket 101, the rotating mass body 104, the pinion 111, and the connecting shaft 113 can be used as the urging force for applying tension to the chain 16, so that the spring force Fs of the spring 103 is reduced. This contributes to reducing the size and weight of the spring 103.

The pinion 111, the connecting shaft 103, and the rotating mass body 104 are rotated by the forward and backward movement of the sprocket 101. For this reason, the moment of inertia of the tensioner 100 when the sprocket 101 moves back and forth is obtained by adding the moments of inertia of the pinion 111 and the connecting shaft 113 to the moment of inertia of the rotating mass 104.
Therefore, in order to obtain a preset predetermined moment of inertia as the moment of inertia of the tensioner 100, the moment of inertia of the rotating mass body 104 can be reduced, so that the rotating mass body 104 is reduced in size and weight accordingly.

The spring 103 urges the sprocket 101 to advance toward the chain 16 with the spring force Fs, and urges the pinion 111 to press against the rack 112. For this reason, the spring 103 is provided with a motion conversion for improving the certainty of conversion from the forward / backward movement of the sprocket 101 to the rotational movement of the pinion 111 and the rotating mass body 104 due to engagement or contact between the pinion 111 and the rack 112. It also serves as a means of force.
The spring 103 includes first and second springs 103a and 103b that are tension coil springs. The springs 103 a and 103 b are attached to a pair of attachment portions 102 b provided on the base 102 and a pair of attachment portions 113 b which are both ends of the connecting shaft 113, and are attached across the base 102 and the pinion 111. ing.
The rotating mass body 104 is composed of one or more rotating mass bodies, which are a plurality of first and second rotating mass bodies 104a and 104b in this embodiment. The first and second rotating mass bodies 104a and 104b are arranged with the sprocket 101, the first and second pinions 111a and 111b, and the first and second racks 112a and 112b in an axial direction parallel to the rotation axis Li. ing.

Referring mainly to FIG. 2 and appropriately referring to FIG. 1, the pinion 111 defines the rotation amount (or rotation angle) of the pinion 111 around the rotation axis Lp when rotating by the forward and backward movement of the sprocket 101. And an effective radius Rp centered on the rotation axis Lp. The effective radius Rp is a distance between the rotation axis Lp and a contact site P that is a meshing site of the rack 112 of the pinion 111 rolling on the rack 112.
Then, the rotational motion of the rotating mass body 104 occurs around the contact portion P based on the forward moment Ma caused by the spring force Fs and the backward moment Mb caused by the reaction force Fr. This also means that the sprocket 101 moves forward when the forward moment Ma is larger than the backward moment Mb and moves backward when the backward moment Mb is larger than the forward moment Ma.

The effective radius Rp is related to the magnitudes of these moments Ma and Mb, and defines the rotation amount (or rotation angle) of the rotating mass body 104 with respect to the movement amount of the sprocket 101 due to the forward and backward movement. The effective radius Rp is smaller than the maximum radius Ri of the rotating mass body 104 (that is, 1/2 of the outer diameter of the rotating mass body 104).
In addition, the inertial resistance due to the mass of the rotating mass body 104, the pinion 111, and the connecting shaft 113 in the forward / backward movement is extremely smaller than the inertial resistance due to the inertia moment of the rotating mass body 104, the pinion 111, and the connecting shaft 113.

Since the rotating mass body 104 performs a rotational motion by causing the sprocket 101 to move forward and backward, when a fluctuating load F (hereinafter referred to as “fluctuating load”) acts on the sprocket 101, An inertial resistor that generates an inertial resistance against the forward and backward movement of the sprocket 101 is configured.
More specifically, the moment of inertia of the rotating mass body 104 varies at a high frequency (hereinafter referred to as “high frequency”) that is a frequency that is equal to or higher than a preset frequency (hereinafter referred to as “set frequency”). When a load (hereinafter referred to as “high-frequency fluctuating load”) acts on the sprocket 101, the moment of inertia becomes a resistance, and the rotation of the rotating mass body 104 is suppressed, so that the rotating mass body 104 hardly rotates. As a result, the advancing / retreating movement of the sprocket 101 is suppressed, and as a result, the sprocket 101 is set to a value that is almost in a stopped state with little advancing / retreating movement. For this reason, the sprocket 101 is prevented from vibrating due to the high frequency fluctuation load, and the sprocket 101 vibrates at a high frequency due to contact between the components of the tensioner 100, for example, contact between the pinion 111 and the rack 112. Noise.
The high frequency is a frequency including the lowest human audible frequency (about 20 Hz), and the set frequency is set to 10 Hz, for example. And the frequency range from which the vibration suppression effect of the sprocket 101 is acquired by the rotating mass body 104 becomes wider as the set frequency becomes smaller.

On the other hand, when a fluctuating load (hereinafter referred to as “low frequency fluctuating load”) at a low frequency (hereinafter referred to as “low frequency”), which is a frequency lower than the set frequency, acts on the sprocket 101, the sprocket 101 moves forward and backward. Since the rotation resistance due to the moment of inertia of the rotating mass body 104 is small, the sprocket 101 that gradually moves back and forth gradually sets the chain 16 to an appropriate size while gradually increasing or decreasing the tension. Is done.
In FIG. 1, the positions of the sprocket 101 and the pinion 111 that have advanced when the tension of the chain 16 decreases are indicated by two-dot chain lines.

This low-frequency fluctuation load is caused by fluctuations in tension caused by thermal expansion / contraction due to changes in environmental temperature in the environment where the chain 16 is installed, and due to elongation due to changes over time of the chain 16 being used. A reaction force Fr that varies based on this is included.
The tension fluctuation due to the change in the environmental temperature is caused by the sprockets 13 to 15 due to the thermal expansion / contraction of the engine block 2 due to the engine temperature changing between the cold start state of the engine 1 and the state after the warm-up is completed. Variation due to a change in the distance between the rotation axes in between and a variation due to expansion and contraction of the chain 16 due to a change in engine temperature.

Further, when the high frequency fluctuation load acts on the sprocket 101 and the average value of the high frequency fluctuation load changes at a low frequency, the tension of the chain 16 is caused by the sprocket 101 that gradually moves forward and backward according to the average value. It is set to an appropriate size by gradually increasing or decreasing.
As described above, the sprocket 101 is in a state in which the response to the high frequency high frequency component of the variable load is suppressed with respect to the variable load, and the vibration at the high frequency is suppressed. Advancing and retreating in response to the low frequency component of the low frequency, the tension of the chain 16 is set to an appropriate magnitude according to the fluctuating load.

The degree of suppression of the vibration of the sprocket 101 by the rotating mass body 104 with respect to the set frequency and the high frequency fluctuation load can be adjusted by changing the effective radius Rp, changing the inclination angle α, and changing the shape of the contact surface 17c. .
Specifically, by changing the effective radius Rp, the magnitude of the forward moment Ma and the backward moment Mb is adjusted, and the rotation amount (or rotation) of the rotating mass body 104 with respect to the unit movement amount of the sprocket 101 due to the forward and backward movement. Angle) can be adjusted. For this reason, for example, by reducing the ratio of the effective radius Rp to the maximum radius Ri of the rotating mass body 104, the set frequency can be reduced and the degree of suppression of vibration of the sprocket 101 can be improved.
Further, for example, by increasing the inclination angle α, the amount of rotation of the rotary mass body 104 with respect to the unit advance / retreat amount of the chain 16 increases, so the set frequency is reduced and the degree of suppression of vibration of the sprocket 101 is improved. Can do.

Next, operations and effects of the embodiment configured as described above will be described.
In the tensioner 100, the sprocket 101 moves forward and backward according to a load F that is a force including the spring force Fs of the spring 103 and the reaction force Fr from the chain 16, and moves forward when the tension of the chain 16 decreases. When the tension is increased and retracted to decrease the tension, the tension of the chain 16 can be set to an appropriate magnitude.

The tension 100 includes a rotating mass body 104 and a rack and pinion mechanism 110 that converts the advancing and retreating motion of the sprocket 101 into the rotating motion of the rotating mass body 104. The rotating mass body 104 is moved forward and backward by the inertia moment. Constitutes an inertial resistance body for.
As a result, when a fluctuating load caused by the tension fluctuation acts on the sprocket 101, the sprocket 101 is rotated by the rack and pinion mechanism 110 so that the forward / backward movement is converted into the rotational movement of the rotary mass 104. Therefore, the moment of inertia of the rotating mass body 104 becomes a resistance to the rotational motion of the rotating mass body 104 due to the variable load, and the sprocket 101 is restrained from moving forward and backward due to the variable load. For this reason, the vibration of the sprocket 101 generated by the fluctuating load is suppressed, and the noise generated by the contact of the constituent members of the tensioner 100 due to the vibration is reduced. As the fluctuation frequency of the fluctuating load increases, the vibration suppression effect of the sprocket 101 by the rotating mass body 104 is enhanced, so that the noise reduction effect in the tensioner 100 is also enhanced.
In addition, since the forward and backward movement of the sprocket 101 due to the high frequency fluctuation load is suppressed, the string vibration of the chain 16 generated by the forward and backward movement of the sprocket 101 is suppressed, and noise caused by the string vibration can be reduced.

  On the other hand, fluctuations in the load F due to thermal expansion / contraction due to changes in the environmental temperature, which is the temperature of the engine block 2 depending on the operating state of the engine 1, and expansion due to changes over time of the chain 16, Is slow and the frequency of the fluctuating load is low, the sprocket 101 slowly advances and retreats, so that the resistance due to the moment of inertia with respect to the rotational motion of the rotating mass 104 is reduced, so that the sprocket 101 gradually advances or retracts. Thus, the tensioner 100 can set the tension of the chain 16 to an appropriate magnitude.

In addition, in the structure in which the vibration of the sprocket 101 on which the variable load acts is suppressed by the inertial resistance, the moment of inertia that can be set to a value larger than the mass of the rotating mass body 104 is used. The tensioner 100 can be reduced in size while improving the suppression effect.
Further, since vibration of the sprocket 101 due to load fluctuation is suppressed without using pressure oil, it is not necessary to increase the pressure oil supply passage for the tensioner, increase the amount of pressure oil used, and increase the capacity of the pressure oil supply source. Therefore, the cost for installing the tensioner 100 can be reduced.

  Furthermore, the sprocket 101 is rotatably supported by the rack and pinion mechanism 110 by using the connecting shaft 113 that is a constituent member of the rack and pinion mechanism 110 as a support member that rotatably supports the sprocket 101. Therefore, compared with the case where a dedicated support member that rotatably supports the sprocket 101 is provided, the number of parts is reduced, so that the tensioner 100 can be reduced in size and the cost can be reduced.

The rack and pinion mechanism 110 that converts the advancing / retracting motion of the sprocket 101 into the rotating motion of the rotating mass body 104 includes a pinion 111 that rotates the rotating mass body 104 by rotating by the advancing / retreating motion of the sprocket 101.
Thereby, in addition to the moment of inertia of the rotating mass body 104, the moment of inertia of the pinion 111 suppresses the forward / backward movement of the sprocket 101 according to the variable load, so the sprocket generated by the variable load corresponding to the moment of inertia of the pinion 111. The vibration mass of the rotating mass body 104 can be reduced by reducing the moment of inertia of the rotating mass body 104 in consideration of the increase in the inertia moment of the pinion 111. As a result, the tensioner 100 can be reduced in size.

  Since the pinion 111 and the rotating mass body 104 rotate integrally around the same rotation axis Li, Lp, the structure for rotating the rotating mass body 104 by the rack and pinion mechanism 110 is simplified. The structure of the tensioner 100 including the body 104 and the rack and pinion mechanism 110 is simplified, so that the tensioner 100 can be reduced in size and the cost of the tensioner 100 can be reduced.

  Since the sprocket 101 can rotate around the rotation axes Lp and Li of the pinion 111 and the rotating mass body 104, the pinion 111, the rotating mass body 104, and the sprocket 101 that is a rotatable member are in a concentric state. Therefore, the tensioner 100 can be reduced in size.

A rack 112 that rolls the pinion 111 to rotate the pinion 111 that rotates the rotating mass body 104 guides the sprocket 101 via the pinion 111 so that the sprocket 101 moves forward and backward. By meshing the gears, the forward / backward movement of the sprocket 101 is reliably transmitted to the pinion 111, and the reliability of conversion from the forward / backward movement to the rotational movement by the rack and pinion mechanism 110 is improved. The stability of the vibration suppression effect of the sprocket 101 can be improved.
In addition, since the forward and backward movement of the sprocket 101 is performed via the pinion 111 that is in rolling contact with the rack 112, the friction when the sprocket 101 performs the forward and backward movement with respect to the rack 112 becomes rolling friction. Compared with the case of sliding with respect to 112, the frictional force between the rack 112 and the sprocket 101 can be reduced, and the smoothness of the forward and backward movement of the sprocket 101 can be improved.

  The spring 103 also serves as a motion conversion urging means that presses the pinion 111 against the rack 112. As a result, the spring 103 urges the sprocket 101 and at the same time to urge the pinion 111 against the rack 112, thereby reducing the number of parts of the tensioner 100 and reducing its cost, while reducing the cost of the rack and pinion mechanism. By improving the certainty of conversion from the advancing / retreating motion to the rotating motion by 110, the stability of the vibration suppression effect of the sprocket 101 by the rotating mass body 104 can be improved.

The pinion 111 has an effective radius Rp that defines the rotation amount of the pinion 111 with respect to the movement amount of the sprocket 101 in the forward and backward movement, and the effective radius Rp is smaller than the maximum radius Ri of the rotating mass body 104.
Thereby, the effective radius Rp defines the amount of rotation of the pinion 111 per unit movement amount of the sprocket 101 due to the forward and backward movement, and hence the amount of rotation of the rotating mass body 104. Therefore, by changing the effective radius Rp The characteristics of the rotational resistance of the rotating mass body 104 with respect to the varying frequency of the varying load, that is, the set frequency and the vibration suppression effect of the sprocket 101 by the rotating mass body 104 can be adjusted.
Since the effective radius Rp is smaller than the maximum radius Ri of the rotating mass body 104, the same effect as that obtained when the moment of inertia of the rotating mass body 104 is increased can be obtained without increasing the size of the rotating mass body 104. Therefore, the tensioner 100 can be reduced in size while enhancing the vibration suppressing effect of the sprocket 101 by the rotating mass body 104.

Next, second and third embodiments of the present invention will be described with reference to FIGS. Although the second and third embodiments are partially different from the first embodiment, the other configurations are basically the same. Therefore, the description of the same part will be omitted or simplified, and different points will be mainly described.
In addition, about the member etc. which are the same as the member etc. of 1st Example, or a corresponding member, the term or code | symbol same as the term or code | symbol in 1st Example is fundamentally used.

Referring to FIG. 4, in the second embodiment, the tensioner 200 includes a tension sprocket 201, a base 102, a spring 103, a rotating mass body 204, and a rack and pinion mechanism 110 as a motion conversion mechanism.
The rotating mass body 204 is disposed between the first and second pinions 111a and 111b and the first and second racks 112a and 112b.
The procket 201 is an annular member and is rotatably supported on the outer periphery of the rotating mass body 204. Therefore, the rotary mass body 204 also serves as a support member that supports the sprocket 201 in a rotatable manner and can move forward and backward.

According to the second embodiment, the same operations and effects as the first embodiment are exhibited, and further the following operations and effects are exhibited.
Since the procket 201 is supported on the outer periphery of the rotating mass body 204, the sprocket 201 and the rotating mass body 204 are disposed at the same position in the axial direction parallel to the rotational axis Li, so that the tensioner 200 is reduced in size in the axial direction. In addition, the rotating mass body 204 also serves as a support member that rotatably supports the sprocket 201, thereby reducing the weight.

5 and 6, in the third embodiment, the tensioner 300 includes a tension sprocket 301, a base 102, a rotary mass body 304 including first and second rotary mass bodies 304a and 304b, and a motion. And a spiral belt mechanism 310 as a conversion mechanism.
The spiral belt mechanism 310 includes a spiral spring 312 as a spiral belt, a connection shaft 311 that is a connection portion that connects the spiral spring 312 and the rotating mass body 304 so as to rotate integrally, and a connection shaft 311 as a guided body. And a pair of guide portions 317 as guide bodies for guiding.
The spiral spring 312 is a spring that also serves as an urging means for causing the sprocket 301 to act on the sprocket 301 as a urging force that moves the sprocket 301 that moves forward and backward.

The spiral spring 312 is composed of a pair of first and second spiral springs 312a and 312b arranged with the sprocket 301 in between in an axial direction parallel to the rotation axis Lp of the rotation shaft 311. Each spiral spring 312 a, 312 b has a fixed side end 313 as a fixed portion fixed to the base 102 and a rotation side end 314 as a rotating portion fixed to the rotating shaft 311. A connecting shaft 311 as a rotating part and a rolling element is a support member that rotatably supports the sprocket 301 and is provided integrally with the rotating mass body 304 and rotates integrally with the rotating mass body 304.
Each guide portion 317 is provided by being fixed to the base 102 by integral molding. However, as another example, the guide portion 317 is formed of a member separate from the base 102 and is fixed to the base 102. Also good. Each guide portion 317 includes a slit portion 318 that is slidably fitted so that the rotating shaft 311 rolls while rotating, and defines a moving direction A1 of 301 in the forward and backward movement.

According to the third embodiment, the same operations and effects as the first embodiment are exhibited, and further the following operations and effects are exhibited.
Since the spiral spring 312 that is a component of the motion conversion mechanism also serves as a biasing means that advances the sprocket 301 to apply tension to the chain 16, the cost of the tensioner 300 can be reduced by reducing the number of parts.

Hereinafter, an example in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
The tension sprocket is supported by the base 102 so as to be movable along a linear movement path, and is rotatably supported by a columnar body that moves forward and backward. A rack and pinion mechanism that is a motion conversion mechanism is provided on the columnar body. The rack may be provided with a rack and a pinion that is rotatably supported by the base 102 but does not move forward and backward. In this case, the rotating mass body rotates integrally with the pinion, but does not move forward and backward.
By providing an interlocking member that interlocks the pinion and the tension sprocket, the rotation axis of the pinion and the rotation axis of the tension sprocket may occupy different positions on the movement path due to the forward / backward movement.
The pinion rotating gear may be an arcuate gear instead of the rack 112 that is a linear gear, and the advancing and retreating motion may be a curved motion (for example, an arcuate motion).
The motion conversion mechanism may be a mechanism other than the rack and pinion mechanism and the winding belt, for example, a cam mechanism or a link mechanism.
In the first embodiment, one or more rotating mass bodies 204 in the second embodiment may be further provided.
Each of the rack and pinion mechanisms 110 may include one pinion 111 and a rack 112, and the number of springs 103 may be one.
In the second embodiment, the winding belt mechanism 301 of the third embodiment may be provided instead of the rack and pinion mechanism 110.
The tension sprocket may be rotatably supported by the pinion 111 itself. The tension wheel may be a roller having an outer peripheral surface whose basic shape is a rotating surface.

100, 200, 300 ... tensioners 101, 201, 301 ... tension sprocket 102 ... base 103 ... springs 104, 204, 304 ... rotating mass 110 ... rack and pinion mechanism 111 ... ..Pinion 112... Rack 310... Swivel belt mechanism 311... Rotating shaft 312 .. Swirl spring 317... Guide portion F... Load Fs. Li, Lp, Lt ... rotation axis Ri ... maximum radius Rp ... effective radius

Claims (5)

A tension wheel that is supported by a base so as to be wound around and rotated by a winding transmission member that is stretched around a plurality of rotating wheels, and a support member that rotatably supports the tension wheel; Biasing means for applying a biasing force for advancing and moving the tension wheel forward and backward to the tension wheel, and the tension wheel applies the tension for applying tension to the winding transmission. In a tensioner that can be moved forward by a force and can be moved back by a reaction force from the wound transmission body,
Comprising a rotating mass that is rotatably supported by the base, and a motion converting mechanism that converts the advance withdrawal movement of the tension wheel rotary motion of the rotating masses,
The rotating mass body constitutes an inertial resistance body with respect to the forward / backward movement of the tension wheel by its inertia moment ,
The motion conversion mechanism includes a rotating component that rotates by a forward and backward movement of the tension wheel,
It said support member is in the motion conversion mechanism, and wherein the member der Rukoto which rotates the rotating component or the rotating component and integrally with the tensioner. The motion conversion mechanism includes a rolling element that is the rotating component, and a guide body that rolls the rolling element by advancing and retracting the tension wheel,
2. The tensioner according to claim 1 , wherein the guide body guides the tension wheel through the rolling element such that the rolling element performs the forward and backward movement together with the tension wheel. 3. The tensioner according to claim 2 , wherein the urging means also serves as a motive means for motion conversion that presses the rolling element against the guide body. The rotating component defines an amount of rotation of the rotating component with respect to an amount of movement of the tension wheel in the forward / backward movement and has an effective radius centered on the rotation axis of the rotating component;
The effective radius of any one of claims 1 to 3, characterized in that less than the maximum radius of the rotating mass tensioner. The support member is the rotating mass body;
The tensioner according to any one of claims 1 to 4 , wherein the tension wheel is supported on an outer periphery of the rotating mass body.

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