JP7338795B2 - belt transmission - Google Patents

Description

The present disclosure relates to belt transmissions.

Patent Document 1 includes a crank pulley fixed to a crankshaft of an internal combustion engine, an auxiliary pulley fixed to a rotating shaft of an auxiliary machine provided parallel to the crankshaft, and a crank pulley and an auxiliary machine pulley. A belt wound around a plurality of pulleys and a pair of tensioner pulleys that can oscillate around the rotation axis of an accessory pulley are arranged with the accessory pulley as a boundary in the direction of circulation of the belt to apply tension to the belt. A belt transmission is disclosed that includes a belt tensioner that provides a .

Japanese Patent Application Laid-Open No. 2015-224613

In the belt transmission device disclosed in Patent Document 1, the tensioner pulley is flipped by the belt when the belt is suddenly stretched due to the initial explosion of the internal combustion engine or the like, and the tensioner pulley is pulled back when the pulled tensioner pulley returns to the belt. produces a banging sound.

SUMMARY OF THE INVENTION In view of the circumstances described above, an object of an embodiment of the present invention is to provide a belt transmission device capable of suppressing hammering noise generated in a tensioner pulley.

A belt transmission device according to an embodiment of the present invention includes a crank pulley fixed to a crankshaft of an internal combustion engine, an accessory pulley fixed to a rotating shaft of an accessory provided parallel to the crankshaft, and the crank A belt that is wound around a plurality of pulleys including a pulley and the accessory pulley, and is oscillatable about a pivot axis that extends parallel to the rotation axis of the accessory pulley, and is rotatable in the circulation direction of the belt. a belt tensioner for applying tension to the belt, wherein a pair of tensioner pulleys are arranged with the accessory pulley as a boundary, and one of the pair of tensioner pulleys is elastic by the belt. The weight of one of the tensioner pulleys is set to be heavier than the weight of the other tensioner pulley so that the tensioner pulley is less likely to be torn.

According to the above configuration, even if the belt is suddenly stretched on either the downstream side or the upstream side of the accessory pulley in the circulation direction of the belt, the tensioner pulley is less likely to be flipped by the belt on either side, A hammering sound generated in the tensioner pulley can be suppressed.

In an embodiment of the present invention, in the above configuration, one of the tensioner pulleys is a tensioner pulley arranged downstream of the accessory pulley in the belt circulation direction.

The belt on the downstream side of the accessory pulley in the belt circulation direction tends to be stretched when the rotational speed of the internal combustion engine fluctuates greatly. According to the above configuration, even if the belt on the downstream side of the accessory pulley in the belt circulation direction is suddenly stretched, the tensioner pulley on the downstream side of the accessory pulley is less likely to be flipped by the belt, and the tensioner pulley is hit. Sound can be suppressed.

In an embodiment of the present invention, in the above configuration, the auxiliary machine is a starter that drives the rotary shaft when electric power is supplied when the internal combustion engine is started.

When the internal combustion engine is started, electric power is supplied to drive the rotating shaft of the accessory (motor generator), and the belt on the upstream side of the accessory pulley (MG pulley) is stretched in the belt circulation direction, and the belt on the downstream side is stretched. Loosen. After that, the crankshaft starts to rotate due to the first explosion of the internal combustion engine, and the belt on the downstream side of the accessory pulley (MG pulley) in the belt circulation direction is rapidly stretched, so the tensioner pulley on the downstream side of the accessory pulley is elastic. easily irritated. Further, when the rotational torque of the crank pulley is transmitted to the accessory pulley (MG pulley) via the belt, the belt on the downstream side of the accessory pulley (MG pulley) is stretched in the belt circulation direction, and the belt on the upstream side is stretched. Belt loosens. After that, when the rotation of the crank pulley is assisted by an accessory (motor generator), the belt on the upstream side of the accessory pulley (MG pulley) is rapidly stretched in the belt circulation direction. Tensioner pulleys are easy to flip. That is, the pair of tensioner pulleys arranged on the border of the motor generator are easily flipped by the belt. According to the above configuration, the pair of tensioner pulleys arranged on the boundary of the motor generator is less likely to be flipped by the belt, so that hammering noise generated in the tensioner pulleys can be suppressed.

In the embodiment of the present invention, in the above configuration, the tensioner pulley arranged downstream of the accessory pulley in the circulation direction of the belt is less likely to be repelled from the belt. The weight of the pulley is set to be heavier than the weight of the tensioner pulley arranged on the upstream side of the accessory pulley in the circulation direction of the belt.

According to the above configuration, even if the belt on the downstream side of the accessory pulley in the belt circulation direction is suddenly stretched due to the initial combustion of the internal combustion engine, the tensioner pulley on the downstream side of the accessory pulley in the belt circulation direction is pulled by the belt. It becomes difficult to be flipped, and it is possible to suppress the hammering sound generated in the tensioner pulley on the downstream side.

In the embodiment of the present invention, in the above configuration, the plurality of pulleys include an upstream pulley provided upstream of the accessory pulley in the belt circulation direction, and a pulley provided downstream of the accessory pulley. a downstream pulley, wherein the length of the belt from the accessory pulley to the downstream pulley is longer than the length of the belt from the upstream pulley to the accessory pulley; One tensioner pulley is arranged between the accessory pulley and the downstream pulley.

According to the above configuration, since the length of the belt from the accessory pulley to the downstream pulley is longer than the length of the belt from the upstream pulley to the accessory pulley, the belt is located downstream of the accessory pulley in the belt circulation direction. Tensioner pulleys on the side are more likely to be flipped than tensioner pulleys on the upstream side. As a result, one of the tensioner pulleys, which is heavier than the other tensioner pulley, is arranged between the accessory pulley and the downstream pulley, making it difficult for the tensioner pulley to be flipped. Hammering noise generated in the pulley can be suppressed.

In the embodiment of the present invention, in the configuration described above, the belt tensioner includes a first arm and a second arm that respectively support the pair of tensioner pulleys, and fixed to the internal combustion engine, the first arm and the second arm. a housing in which each arm is rotatably supported, wherein each of the pair of tensioner pulleys includes a pulley body, a fastening member that attaches the pulley body to the first arm or the second arm, and the pulley body. and a spacer provided between the fastening member, and the one tensioner pulley is heavier than the other tensioner pulley. The thickness of the spacer of the pulley is set thicker than the thickness of the spacer of the other tensioner pulley.

According to the above configuration, only by making the thickness of the spacer of one of the tensioner pulleys thicker than the thickness of the spacer of the other tensioner pulley, the weight of one of the tensioner pulleys is reduced to that of the other tensioner pulley. Since it can be made heavier than the weight of the pulley, there is no need to change the weight of each pulley body, and parts can be shared.

According to the embodiment of the present invention, even if the belt is suddenly stretched due to the initial explosion of the internal combustion engine or the like, one of the pair of tensioner pulleys is less likely to be flipped by the belt, and a hammering sound is generated in one of the tensioner pulleys. can be suppressed.

1 is a front view schematically showing a belt transmission device according to an embodiment of the invention; FIG. 1 is a perspective view of a belt tensioner according to an embodiment of the invention as viewed from the internal combustion engine side; FIG. FIG. 3 is a front view of the belt tensioner shown in FIG. 2 as viewed from the internal combustion engine side; FIG. 3 is an exploded perspective view showing the housing and arm assembly shown in FIG. 2; FIG. 5 is an exploded perspective view of the arm assembly shown in FIG. 4; FIG. 4 is a sectional view taken along the line VI-VI showing the structure of the tensioner pulley shown in FIG. 3; FIG. 4 is a sectional view taken along line VII-VII showing the structure of the tensioner pulley shown in FIG. 3;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, and are merely illustrative examples. do not have.

FIG. 1 is a front view schematically showing a belt transmission device 1 according to an embodiment of the invention. 2 is a perspective view of the belt tensioner 5 according to the embodiment of the present invention as seen from the internal combustion engine 21 side, and FIG. 3 is a front view of the belt tensioner 5 shown in FIG. 2 as seen from the internal combustion engine 21 side. be. 4 is an exploded perspective view showing arm assembly 54 and housing 57 shown in FIG. 2, and FIG. 5 is an exploded perspective view of arm assembly 54 shown in FIG. 6 is a sectional view taken along line VI-VI showing the structure of tensioner pulley 51 shown in FIG. 3, and FIG. 7 is a sectional view taken along line VII-VII showing the structure of tensioner pulley 52 shown in FIG.

As shown in FIG. 1, the belt transmission device 1 according to the embodiment of the present invention includes a crank pulley 2, an accessory pulley 3, a belt 4 and a belt tensioner 5. As shown in FIG.

A crank pulley 2 is a pulley fixed to a crankshaft 211 of the internal combustion engine 21 . The crankshaft 211 is the main shaft of the internal combustion engine 21 and is arranged substantially in the center of the lower region of the internal combustion engine 21 . The crank pulley 2 rotates as the crankshaft 211 rotates. When the internal combustion engine 21 is started, the rotation of the crank pulley 2 causes the crankshaft 211 to rotate.

The accessory pulley 3 is a pulley fixed to a rotating shaft 311 of the accessory 31 provided parallel to the crankshaft 211 of the internal combustion engine 21 . Auxiliary machine 31 is a device driven by internal combustion engine 21 . The auxiliary machine 31 is, for example, a motor generator 31A, but is not limited to this, and may be a water pump (not shown) or a compressor 31C for an air conditioner.

Belt 4 is wound around a plurality of pulleys including crank pulley 2 and accessory pulley 3 . In addition to the crank pulley 2 and the accessory pulley 3, the plurality of pulleys include, for example, a water pump pulley 3B provided on the rotation shaft 311B of the water pump, an air conditioner pulley 3C provided on the rotation shaft 311C of the compressor 31C for the air conditioner, Or the idler pulley 6 . However, the plurality of pulleys need not include all of these pulleys, and may include at least the crank pulley 2 and the accessory pulley 3 . Also, as shown in FIG. 1, an idler pulley 7 may be provided between the air conditioner pulley 3C and the crank pulley 2 to apply tension. Since the belt 4 is wound around a plurality of pulleys including the crank pulley 2 and the auxiliary pulley 3 in this way, the rotational torque of the crank pulley 2 is transmitted to the auxiliary pulley 3 via the belt 4, Rotational torque of the accessory pulley 3 is transmitted to the crank pulley 2 via the belt 4 .

The belt tensioner 5 is swingable about an axis parallel to the rotating shaft 311 of the accessory pulley 3, and a pair of tensioner pulleys 51 and 52 are arranged with the accessory pulley 3 as a boundary in the circulation direction of the belt 4. , tensioning the belt 4 . A pair of tensioner pulleys 51 and 52 of the belt tensioner 5 are individually swingable. As shown in FIGS. 2 and 3, a plate-like spring 53 is provided between the pair of tensioner pulleys 51 and 52 to connect the pair of tensioner pulleys 51 and 52 to each other. Therefore, when one belt 4 is stretched across the accessory pulley 3 in the circulation direction of the belt 4 and the other belt 4 is loosened, the stretched belt 4 pushes up one tensioner pulley 51 (52) and the other tensioner pulley 51 (52). The pulley 52 (51) is pushed down to remove the slackness of the slackened belt 4. - 特許庁In this embodiment, the pair of tensioner pulleys 51 and 52 are provided so that their centers sandwich a vertically extending line passing through the swing axis of the belt tensioner 5 .

In the belt tensioner 5 according to the embodiment of the present invention, the pair of tensioner pulleys 51 and 52 are arranged such that either one of the pair of tensioner pulleys 51 and 52 is less likely to be flipped by the belt 4 . (52) is made heavier than the weight of either tensioner pulley 52 (51).

As a result, one tensioner pulley 51 (52) is heavy, so that it is difficult to be flipped by the belt 4, and after being flipped, it returns to the side of the belt 4 and can suppress the hammering sound generated when it collides with the belt 4. - 特許庁In addition, the other tensioner pulley 52 (51) is flipped because the belt tensioner 5 as a whole tends to swing in the direction in which the one tensioner pulley 51 (52) moves downward. The force that tends to return to the belt 4 side is weakened when the belt 4 hits the belt 4, and the hammering sound generated when it collides with the belt 4 can be suppressed. In this manner, the weights of the pair of tensioner pulleys 51 and 52 are made different so that one of the tensioner pulleys 51 (52) is less likely to be flipped by the belt 4, so that the tensioner pulleys 51 and 52 collide with the belt 4. It is possible to suppress the hammering sound that occurs when At this time, one of the tensioner pulleys 51 (52) with increased weight has a higher effect of suppressing hammering noise than the other tensioner pulley 52 (51).

Therefore, for example, when the belt 4 downstream of the auxiliary pulley 3 in the circulation direction of the belt 4 is abruptly stretched, the tensioner pulley 51 arranged downstream of the auxiliary pulley 3 in the circulation direction of the belt 4 is tensioned. When the hammering sound is remarkable, the weight of the tensioner pulley 51 arranged on the downstream side is set lower than that of the accessory pulley 3 so that the tensioner pulley 51 arranged on the downstream side is less likely to be flipped by the belt 4. It is preferable to make it heavier than the tensioner pulley 52 arranged on the upstream side. The weight of the tensioner pulley 51 arranged on the downstream side of the accessory pulley 3 is made, for example, about 90 g heavier than the weight of the tensioner pulley 52 arranged on the upstream side.

Further, for example, when the belt 4 on the upstream side of the accessory pulley 3 in the circulation direction of the belt 4 is abruptly stretched, the tensioner pulley 52 arranged on the upstream side of the accessory pulley 3 in the circulation direction of the belt 4 is tensioned. When the hammering sound is remarkable, the weight of the tensioner pulley 52 arranged on the upstream side is set lower than that of the accessory pulley 3 so that the tensioner pulley 52 arranged on the upstream side is less likely to be flipped by the belt 4 . It is preferable to make it heavier than the tensioner pulley 51 arranged downstream. The weight of the tensioner pulley 52 arranged on the upstream side of the accessory pulley 3 is set to be, for example, about 90 g heavier than the weight of the tensioner pulley 51 arranged on the downstream side.

In the belt transmission device 1 according to the embodiment of the present invention, one of the tensioner pulleys 51 ( 52 ) described above is the tensioner pulley 51 arranged downstream of the accessory pulley 3 in the circulation direction of the belt 4 . One of the tensioner pulleys 51 (52) described above is a pulley that is heavier than the other tensioner pulley 52 (51). The weight of the tensioner pulley 51 arranged downstream of the auxiliary machine pulley 3 is arranged upstream so that the tensioner pulley 51 arranged downstream of the machine pulley 3 is not easily flipped by the belt 4. It is set heavier than the weight of 52.

Since the belt 4 is stretched on the downstream side of the accessory pulley 3 when the rotational speed of the internal combustion engine 21 fluctuates greatly, such as when the internal combustion engine 21 is started, the tensioner pulley 51 disposed downstream of the accessory pulley 3 is It is easily repelled by the belt 4. According to the belt transmission device 1 according to the embodiment of the present invention described above, even if the belt 4 on the downstream side of the accessory pulley 3 in the circulation direction of the belt 4 is suddenly stretched, the tensioner pulley is 51 is less likely to be flipped by the belt 4, and hammering noise generated in the tensioner pulley 51 can be suppressed.

In the belt transmission device 1 according to the embodiment of the invention, the accessory 31 is a motor generator 31A. The motor generator 31A is driven by a rotating shaft 311A when electric power is supplied when the internal combustion engine 21 is started. 4 to the crank pulley 2, it functions as a starter capable of rotating (cranking) the crankshaft 211 to which the crank pulley 2 is fixed. The motor generator 31A also functions as a generator capable of generating power by rotating the rotation shaft 311A by transmitting the rotational torque of the crank pulley 2 to the MG pulley 3A via the belt 4 . The motor generator 31A may have a function of assisting the rotation of the crank pulley 2 (that is, the crankshaft 211) by being supplied with electric power while the internal combustion engine 21 is running.

When the internal combustion engine 21 is started, electric power is supplied to drive the rotation shaft 311A of the motor generator 31A, and the belt 4 on the downstream side of the MG pulley 3A in the circulation direction of the belt 4 is loosened. After that, the crankshaft 211 starts rotating due to the initial explosion of the internal combustion engine 21, and the belt 4 on the downstream side of the MG pulley 3A in the circulation direction of the belt 4 is abruptly stretched. It is easy to be repelled. In this way, the tensioner pulley 51 located downstream of the motor generator 31</b>A functioning as a starter in the circulation direction of the belt 4 is easily flipped by the belt 4 . According to the belt transmission device 1 according to the embodiment of the present invention described above, even with such a configuration, it is possible to suppress the hammering sound generated when the tensioner pulleys 51 and 52 collide with the belt 4 . If the motor generator 31A has a function of assisting the rotation of the crank pulley 2, the belt 4 on the upstream side of the MG pulley 3A in the circulation direction of the belt 4 is loosened before the start of the assist, and the belt 4 is loosened when the assist is started. Since the belt 4 on the upstream side of the MG pulley 3A is stretched in the circulation direction of , the tensioner pulley 52 of the motor generator 31A located on the upstream side in the circulation direction of the belt 4 is easily flipped by the belt 4 . Even in such a case, the belt transmission device 1 according to the embodiment of the present invention described above can suppress the hammering sound generated when the tensioner pulleys 51 and 52 collide with the belt 4 .

In the belt transmission device 1 according to the embodiment of the present invention, the tensioner pulley 51 (hereinafter referred to as the "power running side tensioner pulley 51") is arranged downstream of the MG pulley 3A in the circulation direction of the belt 4 when the internal combustion engine 21 is initially fired. ) is less likely to be repelled from the belt 4, the weight of the power running side tensioner pulley 51 is shifted to a tensioner pulley 52 (hereinafter referred to as “regenerative side tensioner pulley 52”) disposed upstream of the accessory pulley 3 in the circulation direction of the belt 4. ) weight.

According to the belt transmission device 1 according to the embodiment of the present invention described above, even if the pulley on the downstream side of the MG pulley 3A in the circulation direction of the belt 4 is abruptly stretched due to the initial explosion of the internal combustion engine 21, the power running side tensioner pulley 51 is hard to be flipped, and the hammering sound generated in the power running side tensioner pulley 51 can be suppressed. When the internal combustion engine 21 is started, the sound generated in the internal combustion engine 21 is smaller than that generated when the internal combustion engine 21 is running, and the striking sound generated when the tensioner pulleys 51 and 52 collide with the belt 4 is noticeable. It is preferable to make the power running side tensioner pulley 51 heavy.

In the belt transmission device 1 according to the embodiment of the present invention, the plurality of pulleys are an upstream pulley 8 provided upstream of the accessory pulley 3 in the circulation direction of the belt 4 and a plurality of pulleys provided downstream of the accessory pulley 3. and a downstream pulley 9 . For example, the upstream pulley 8 provided on the upstream side of the accessory pulley 3 is the idler pulley 6, and the downstream pulley 9 provided on the downstream side of the accessory pulley 3 is the air conditioner pulley 3C.

The length of the belt 4 from the auxiliary pulley 3 to the downstream pulley 9 is longer than the length of the belt 4 from the upstream pulley 8 to the auxiliary pulley 3. One of the tensioner pulleys 51 ( 52 ), which is heavier than the weight, is arranged between the accessory pulley 3 and the downstream pulley 9 . For example, when the accessory pulley 3 is the MG pulley 3A, the downstream pulley 9 is the air conditioner pulley 3C, and the upstream pulley 8 is the idler pulley 6, the length of the belt 4 from the MG pulley 3A to the air conditioner pulley 3C is A power side tensioner pulley 51 longer than the length of the belt 4 from the pulley 6 to the MG pulley 3A and heavier than the regeneration side tensioner pulley 52 is arranged between the MG pulley 3A and the air conditioner pulley 3C.

According to the belt transmission device 1 according to the embodiment of the present invention described above, the length of the belt 4 from the auxiliary pulley 3 to the downstream pulley 9 is equal to the length of the belt 4 from the upstream pulley 8 to the auxiliary pulley 3. , the tensioner pulley 51 located downstream of the accessory pulley 3 in the circulation direction of the belt 4 is more likely to be flipped than the tensioner pulley 52 located upstream. Since one of the tensioner pulleys 51, which is heavier than the other tensioner pulley 52, is arranged between the accessory pulley 3 and the downstream side pulley 9, the tensioner pulley 51 is less likely to be flipped, and the tensioner pulley 51 is affected. You can suppress the hammering sound.

As shown in FIG. 4 , the belt tensioner 5 according to the embodiment of the invention includes first and second arms 55 and 56 and a housing 57 . The first arm 55 and the second arm 56 are parts that support the pair of tensioner pulleys 51 and 52 described above, respectively. The first arm 55 and the second arm 56 are combined to form one arm assembly 54, and as shown in FIG. 5, can swing independently of each other. The housing 57 is fixed to the auxiliary device 31 (motor generator 31A), and supports the first arm 55 and the second arm 56 so as to swing.

As shown in FIGS. 6 and 7, the pair of tensioner pulleys 51 and 52 have pulley bodies 511 and 521, bolts 512 and 522 and spacers 513 and 523, respectively. The bolts 512 and 522 are fastening members that rotatably attach the pulley bodies 511 and 521 to the first arm 55 or the second arm 56 . Spacers 513 , 523 are provided between pulley bodies 511 , 521 and bolts 512 , 522 . 6 and 7, the shapes of the first arm 55 and the second arm 56 are simplified. In the example shown in FIGS. 6 and 7, bearings 514 and 524 are provided between shaft members 551 and 561 provided on the first arm 55 or the second arm 56 and pulley bodies 511 and 521. Spacers 513 and 523 are fitted to 524 . Bearings 514 and 524 are fixed between the spacers 513 and 523 and the shaft members 551 and 561 by bolts 512 and 522 passing through the spacers 513 and 523 . The spacers 513 and 523 are provided to prevent foreign matter from entering the tensioner pulleys 51 and 52 through the gaps between the pulley bodies 511 and 521 and the bolts 512 and 522, thereby inhibiting the rotation of the tensioner pulleys 51 and 52. Both spacers 513 and 523 are made of the same material, such as a metal plate.

Then, one of the tensioner pulleys 51 (52) has a spacer 513 (523) so that the weight of one of the tensioner pulleys 51 (52) is greater than the weight of the other tensioner pulley 52 (51). ) is set thicker than the thickness of the other spacer 523 (513). That is, by making the thickness of the spacer 513 (523) of the tensioner pulley 51 (52) which is made heavier out of the pair of tensioner pulleys 51 and 52 thicker than the thickness of the spacer 523 (513) of the other tensioner pulley 52, , the tensioner pulley 51 (52) to be made heavier is made heavier than the other tensioner pulley 52 (51).

According to the belt transmission device 1 according to the embodiment of the present invention described above, the thickness of the spacer 513 (523) of one of the tensioner pulleys 51 (52) is greater than the weight of the other tensioner pulley 52 (51). By increasing the weight, the weight of one of the tensioner pulleys 51 (52) can be made heavier than the weight of the other tensioner pulley 52.例文帳に追加Therefore, even if the pair of pulley bodies 511 and 521 are made of the same material and shape, the pair of tensioner pulleys 51 and 52 can have different weights. and can reduce costs. In order to make the spacers 513 and 523 different in weight, it is possible to take measures such as making the material different instead of making the thickness different. This also helps prevent assembly errors because it becomes easier to grasp the

The present invention is not limited to the above-described embodiments, and includes modifications of the above-described embodiments and modes in which these modes are combined as appropriate.

This application is based on Japanese Patent Application No. 2020-135516 filed on August 11, 2020, the content of which is incorporated herein by reference.

1 belt transmission device 2 crank pulley 21 internal combustion engine 211 crankshaft 3 accessory pulley 3A MG pulley (motor generator pulley)
31 Auxiliary machine 31A Motor generator 311 Rotating shaft 311A Rotating shaft 3B Water pump pulley 311B Rotating shaft 3C Air conditioner pulley 31C Air conditioner compressor 311C Rotating shaft 4 Belt 5 Belt tensioner 51 Tensioner pulley 511 Pulley body 512 Bolt 513 Spacer 514 Bearing 52 Tensioner pulley 521 pulley body 522 bolt 523 spacer 524 bearing 53 spring 54 arm assembly 55 first arm 551 shaft member 56 second arm 561 shaft member 57 housing 6 idler pulley 7 idler pulley 8 upstream pulley 9 downstream pulley

Claims (4)

a crank pulley fixed to the crankshaft of an internal combustion engine;
an auxiliary machine pulley fixed to a rotating shaft of the auxiliary machine provided parallel to the crankshaft;
a belt wound around a plurality of pulleys including the crank pulley and the accessory pulley;
A pair of tensioner pulleys are arranged with the auxiliary pulley as a boundary in the circulation direction of the belt, the pair of tensioner pulleys being swingable about a swing shaft extending parallel to the rotation axis of the accessory pulley. A belt tensioner that has a plate-shaped spring that connects to each other and applies tension to the belt;
with
The pair of tensioner pulleys are provided so that their centers sandwich a line extending in the vertical direction passing through the swing axis of the belt tensioner, and the tensioner is arranged downstream of the accessory pulley in the circulation direction of the belt. The weight of the tensioner pulley arranged on the downstream side of the accessory pulley is set to be heavier than the weight of the tensioner pulley arranged on the upstream side of the accessory pulley so that the pulley is less likely to be flipped by the belt. ,
belt transmission . The auxiliary machine is a starter that drives the rotating shaft by supplying electric power when the internal combustion engine is started.
The belt transmission device according to claim 1 . a crank pulley fixed to the crankshaft of an internal combustion engine;
an auxiliary machine pulley fixed to a rotating shaft of the auxiliary machine provided parallel to the crankshaft;
a belt wound around a plurality of pulleys including the crank pulley and the accessory pulley;
A pair of tensioner pulleys are arranged with the auxiliary pulley as a boundary in the circulation direction of the belt, the pair of tensioner pulleys being swingable about a swing shaft extending parallel to the rotation axis of the accessory pulley. A belt tensioner that has a plate-shaped spring that connects to each other and applies tension to the belt;
with
The plurality of pulleys further includes an upstream pulley provided upstream of the accessory pulley in the belt circulation direction, and a downstream pulley provided downstream of the accessory pulley,
The weight of one of the pair of tensioner pulleys is set to be heavier than the weight of the other tensioner pulley so that one of the pair of tensioner pulleys is less likely to be flipped by the belt. is,
The length of the belt from the accessory pulley to the downstream pulley and the length of the belt from the upstream pulley to the accessory pulley are different ,
Either one of the tensioner pulleys is disposed between the upstream pulley and the downstream pulley , the pulley having the longer length of the belt from the accessory pulley, and the accessory pulley ,
belt transmission. The belt tensioner is
a first arm and a second arm respectively supporting the pair of tensioner pulleys;
a housing fixed to the internal combustion engine and rotatably supporting the first arm and the second arm;
including
Each of the pair of tensioner pulleys:
a pulley body;
a fastening member that attaches the pulley body to the first arm or the second arm;
a spacer provided between the pulley body and the fastening member;
has
The thickness of the spacer of the one tensioner pulley is adjusted so that the weight of the one tensioner pulley is greater than the weight of the other tensioner pulley. is set thicker than the thickness of
The belt transmission device according to any one of claims 1 to 3 .

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