JP6911690B2 - Balancer system gears - Google Patents

Description

The present invention relates to a balancer system gear, and particularly to a synchronous gear that rotationally drives an eccentric shaft in a balancer system mounted on an automobile engine.

In recent years, the use of diesel engines is increasing, and pistons are becoming larger in diameter and longer strokes. As a result, engine vibration tends to increase, and many technologies to reduce this have been proposed. ing. Among them, as a mechanism for actively reducing vibration, there is a balancer system composed of two eccentric shafts and synchronous gears for rotating and driving them. Steel gears are often used as the synchronous gears of the balancer system, but there may be problems such as loud noise and difficulty in weight reduction.

In response to the above problems, Patent Document 1 discloses a gear having composite teeth, characterized in that the teeth of the gear are composite teeth composed of a metal tooth portion and a synthetic resin tooth portion. Further, there is disclosed a gear characterized in that the tooth that receives a large amount of torque in the gear is a tooth of a composite material, and the other tooth is a synthetic resin molded tooth formed only of a synthetic resin. According to Patent Document 1, the strength is maintained at the metal tooth portion, and the meshing with the mating gear is performed at the resin tooth portion or both the resin tooth portion and the metal tooth portion, and the rattling noise due to backlash is reduced. Has been done. In addition, it is said that the strength can be maintained by using composite teeth for the teeth that engage at the maximum torque of the gear, and synthetic resin molded teeth can be used for the teeth where the torque is small to satisfy both strength and noise. There is.

Jikkenhei 3-28353 Gazette

The above-mentioned technique of Patent Document 1 has a configuration in which the mating gear first abuts on the resin tooth portion to absorb the backlash noise, and then abuts on the metal tooth portion to transmit torque. Since the resin tooth portion with which the gear comes into contact has a lower strength than the metal tooth portion, further improvement has been desired from the viewpoint of the strength (durability) of the gear.

An object of the present invention has been made in view of the above points, and an object of the present invention is to provide a balancer system gear having sufficient strength while reducing noise.

The present invention has an annular portion that is fitted to a rotating shaft and rotates together with the rotating shaft, and a gear portion provided on the outer circumference of the annular portion in order to achieve the above object. The balancer system gear is divided into two or more types of members in the circumferential direction of the annular portion, and the two or more types of members are made of fiber-reinforced resin having different strengths.

More specific configurations of the present invention are described in the claims.

According to the present invention, it is possible to provide a balancer system gear having sufficient strength while reducing noise.

Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is a schematic diagram which shows the balancer system of an automobile engine. It is a figure which shows the relationship between the time-dependent change of torque in a balancer system, and the meshing position of a gear. It is a schematic diagram of the gear for the balancer system of Example 1. It is an enlarged view of a part of the gear part of FIG. It is a schematic diagram of the gear for the balancer system of Example 2. It is a schematic diagram of the gear for the balancer system of Example 3. It is an enlarged view of the B part of FIG. It is an enlarged view of the C part of FIG. It is a schematic diagram of the gear for the balancer system of Example 4.

The present invention relates to a balancer system gear (hereinafter, also referred to as a "synchronous gear") which is a component of a balancer system (balancer gear system) attached to an engine of an automobile or the like, and particularly a eccentric shaft. It relates to a synchronous gear that is driven to rotate.

First, the synchronous gear of the balancer system attached to the crankshaft connected to the piston of the engine will be described.

FIG. 1 is a schematic view showing a balancer system for an automobile engine. In this figure, the engine 200 represents one of a four-cylinder reciprocating internal combustion engine. A piston 26 is installed in the cylinder 25 of the engine 200. A small end 29 of the connecting rod 28 is rotatably coupled to the piston pin 27 of the piston 26. The large end 30 of the connecting rod 28 is rotatably coupled to the crank pin 21 of the crankshaft 20.

The crankshaft 20 includes a crank pin 21, a crank arm 22, a crank journal 23, and a counterweight 24. The crank pin 21 is coupled to the crank arm 22. Further, the crank arm 22 is coupled to the crank journal 23. The crank journal 23 is rotatably supported by a crank bearing 33. A flywheel 31 is attached to the crankshaft 20. A dentition (not shown) is formed on the outer peripheral portion of the flywheel 31. In this dentition, gears of a starter (not shown) are arranged so as to mesh with each other.

A drive gear 32 is further attached to the crankshaft 20. The synchronous gear 1 is arranged so as to mesh with the drive gear 32. Further, the synchronous gear 1 is arranged so that the synchronous gear 2 meshes with the synchronous gear 1. The synchronous gears 1 and 2 have a diameter half that of the drive gear 32.

With the explosion of fuel inside the cylinder 25, the piston 26 reciprocates in the Y-axis direction indicated by the alternate long and short dash line. In the case of a 4-cylinder reciprocating internal combustion engine, two explosions occur while the drive gear 32 makes one rotation, so that the synchronous gears 1 and 2 make one rotation while the drive gear 32 makes a half rotation. Since an explosion occurs once while the synchronous gears 1 and 2 make one rotation, the teeth of the synchronous gears 1 and 2 that receive a large torque generated by the explosion are the same each time.

The torque received by the synchronous gear of the balancer system will be further described. FIG. 2 is a diagram showing the relationship between the time-dependent change in torque in the balancer system and the meshing position of the gears. In FIG. 2, a schematic diagram showing the meshing positions of the synchronous gears 1 and 2 is also shown in a graph showing a change in torque with time. As shown in FIG. 2, in the balancer system, since the drive gear and the synchronous gears 1 and 2 rotate in synchronization with each other, the teeth of the synchronous gear that mesh with each other at the moment when the torque that fluctuates in synchronization with the rotation of the crank becomes maximum It will be the same (the gear A in FIG. 2). From this, if the operation that is overloaded with respect to the strength of the gear is continued, there is a high possibility that the teeth that mesh with each other at the moment of maximum torque described above will be damaged. Therefore, in the balancer system gear of the present invention, the teeth constituting the A portion are made of a material having higher strength than the teeth of the other portions.

FIG. 3 is a schematic view of the balancer system gear of the first embodiment. As shown in FIG. 3, the synchronous gear 3a of the present embodiment has an annular portion 4 that is fitted to a rotating shaft and rotates together with the rotating shaft, and a gear portion 7 provided on the outer circumference of the annular portion 4. The gear portion 7 has gear portions 5 and 6 composed of two types of members having different strengths. The gear portions 5 and 6 have a configuration arranged in the circumferential direction of the annular portion 4. The gear portion 5 is arranged in a portion having the highest torque load, and is composed of a first member made of the material having the highest strength among the gear portions 7. On the other hand, the gear portion 6 is arranged in a portion other than the portion where the gear portion 5 is arranged, and is composed of a second member made of a material having a strength lower than that of the gear portion 5. Hereinafter, the first member will be referred to as a "high-strength member", and the second member will be referred to as a "low-strength member".

According to the configuration of the synchronous gear 3a described above, since the portion of the gear portion 7 to which the largest torque (load) is applied is composed of a high-strength member, it is possible to sufficiently secure the strength of the synchronous gear 3a. can. On the other hand, since the other parts are made of low-strength members, the noise of the synchronous gear 3a can be reduced. That is, according to this embodiment, it is possible to achieve both the strength of the synchronous gear 3a and the noise reduction at a high level.

As the high-strength member, it is preferable to use a material having a Young's modulus of 70 GPa or more. For example, fiber reinforced resins such as steel (Young rate: 206 GPa), carbon fiber reinforced plastic (Carbon Fiber Reinforced Plastic, CFRP, Young rate: 125 GPa) and aramid fiber reinforced plastic (Aramid Fiber Reinforced Plastics, AFRP, Young rate: 78 GPa). Can be used. The strength of the fiber reinforced plastic can be adjusted by changing the type of fiber, the filling amount, or the type of matrix resin. The source of Young's modulus in the present specification is "http://www.hokkan-kogyo.co.jp/frp.html" (reference material of FRP Association).

As the low-strength member, it is preferable to use a material having a Young's modulus of less than 10 GPa. For example, a resin such as glass fiber reinforced plastic (Glass Fiber Reinforced Plastics, GFRP, Young ratio: 8.7 GPa) or polyaminoamide (less than 10 GPa) in which the matrix resin is a phenol resin can be used.

The annulus portion 4 is not particularly limited, but it is preferable to use steel having high strength. When both the annulus portion 4 and the gear portion 5 are made of steel, both may be integrally molded members. In this case, by using the ring portion 4 and the gear portion 5 as one member, the manufacturing cost can be reduced as compared with the case where both are manufactured separately.

As an example of a preferable configuration of the synchronous gear 3a, there is an embodiment in which steel is used for the ring portion 4, fiber reinforced plastic is used for the gear portion 5, and fiber reinforced plastic or resin material having a strength lower than that of the gear portion 5 is used for the gear portion 6. .. With such a configuration, the gear portion 5 is made lighter than steel while having sufficient strength, and the weight of the synchronous gear can be reduced.

Next, the configuration of the gear portion 7 will be described. FIG. 4 is an enlarged view of a part of the gear portion of FIG. As shown in FIG. 4, the gear portion 7 includes teeth 10 and a rim 11 that supports the teeth 10. Here, the height of the teeth 10 _{h t,} the height of the rim 11, _{S R.} Gear unit 7 _is preferably S R / _{h t} is 0.8 or more. If S _R / h _t is less than 1.2, the strength of the gear portion 7 may not be sufficient. The upper limit of S R _/ h _t, is determined based on the general configuration of the gear portion 7.

Next, a method of manufacturing the synchronous gear 3a will be described. A gear portion 7 is formed by casting on the outer circumference of the steel ring portion 4. At this time, a plurality of casting nozzles are arranged so that the high-strength member is ejected from the nozzle arranged in the gear portion 5 and the low-strength member is ejected from the nozzle arranged in the gear portion 6. As shown in FIG. 3, a gear portion 7 composed of a gear portion 5 made of a high-strength member and a gear portion 6 made of a low-strength member can be manufactured. After casting the gear portion 7, the outer circumference of the gear portion 7 is cut to form the teeth 10, whereby the synchronous gear 3a can be completed.

According to the above-described configuration, when the engine is rotationally driven and the synchronous gear 3a is rotated, power is transmitted by a portion of the gear portion 5 made of a high-strength member in the phase of maximum torque. On the other hand, in a range where the torque is small, power is transmitted by the gear portion 6 made of a low-strength member. As a result, it is possible to prevent the high-strength member from acting on the overload in the gear portion 5, and to obtain the effect of reducing noise by the low-strength member in the range in which the gear portion 6 transmits power.

FIG. 5 is a schematic view of the balancer system gear of the second embodiment. The synchronous gear 3b shown in FIG. 5 is a third member having a strength between a high-strength member and a low-strength member between the gear portion 5 made of a high-strength member and the gear portion 6 made of a low-strength member (hereinafter, It is different from the synchronous gear 3a of the first embodiment in that the gear portion 8 made of (referred to as a “medium-strength member”) is arranged. That is, the synchronous gear 3b of the present embodiment has a configuration in which the strength of the member gradually decreases from the gear portion 5 in which the torque load is maximized to the gear portion 8 and the gear portion 6 in which the torque load decreases. Have.

By gradually changing the strength of the gear portion 7 in this way, in addition to the effect of the synchronous gear 3a of the first embodiment, the difference in strain at the interface of each member is reduced, and the synchronous gear 3b is further increased. Strength can be improved and noise can be reduced.

As the medium-strength member constituting the gear portion 8, it is preferable to use a material having a Young's modulus of 10 GPa or more and less than 70 GPa. For example, GFRP (Young's modulus: 41 GPa) in which the matrix resin is an unsaturated polyester resin is preferable. In the above-mentioned fiber reinforced plastic, it is preferable to use a material in which the Young's modulus is adjusted to 10 GPa or more and less than 70 GPa by changing the type of fiber, the filling amount and the type of matrix resin.

As an example of a preferable configuration of the synchronous gear 3b, the ring portion 4 is made of steel, the gear portion 5 is made of fiber reinforced plastic, the gear portion 6 is made of fiber reinforced plastic or resin material having a strength lower than that of the gear portion 5, and the gear portion 8 is made of fiber reinforced plastic. An embodiment in which a fiber reinforced plastic or resin material having a strength lower than that of the gear portion 5 and a strength higher than that of the gear portion 6 is used can be mentioned. With such a configuration, the gear portion 5 is made lighter than steel while having sufficient strength, and the weight of the synchronous gear can be reduced.

FIG. 6 is a schematic view of the balancer system gear of the third embodiment. The synchronous gear 3c shown in FIG. 6 is different from the synchronous gear 3a of the first embodiment in that an elastic body (elastomer) 9 is arranged between the annular portion 4 and the gear portion 7. With such a configuration, in addition to the effect of the synchronous gear 3a of the first embodiment, the impact can be absorbed by the elastic deformation of the elastomer 9. Therefore, the noise of the synchronous gear 3c can be further reduced.

7A is an enlarged view of the B portion of FIG. 6, and FIG. 7B is an enlarged view of the C portion of FIG. As shown in FIGS. 7A and 7B, the boundary between the elastic body 9 and the annulus portion 4 and the contact surface between the elastic body 9 and the gear portion 7 may be wavy rather than flat. Further, the ring portion 4, the elastic body 9 and the gear portion 7 do not have to be in perfect contact with each other, and may be in partial contact with each other. It suffices to have a shape capable of transmitting power from the annulus portion 4 to the elastic body 9 and from the elastic body 9 to the gear portion 7.

Width W of the elastic member 9 is preferably 0.5h _t or more. W is shock absorbing effect is not sufficiently obtained due to the elastic body 9 is less than 0.5h _t. The upper limit of W is determined based on the general configuration of the gear portion 7. The elastic body 9 can be formed by casting, like the gear portion 7.

FIG. 8 is a schematic view of the balancer system gear of the fourth embodiment. The synchronous gear 3d shown in FIG. 8 is a combination of the configurations of the second embodiment and the third embodiment. That is, the synchronous gear 3d shown in FIG. 8 is composed of a medium-strength member having a strength between the high-strength member and the low-strength member between the gear portion 5 made of the high-strength member and the gear portion 6 made of the low-strength member. It differs from the synchronous gear 3a of the first embodiment in that the gear portion 8 is arranged and the elastic body (epolymer) 9 is further arranged between the ring portion 4 and the gear portion 7.

With such a configuration, in addition to the effect of the synchronous gear 3a of the first embodiment, the strength of the gear portion 7 is changed stepwise to reduce the difference in strain at the interface of each member. Can be done. Further, the impact can be absorbed by the elastic deformation of the elastic body 9. Therefore, the strength and noise reduction of the synchronous gear can be further improved.

As the material of the elastic body, for example, nitrile rubber and silicone rubber are suitable, but the material is not limited thereto. Further, as a mode of forming the elastic body 9, the elastic body 9 having the shape shown in this figure may be embedded in the recess provided in the gear portion 7. In this case, recesses may be provided on the front and back surfaces of the gear portion 7, and elastic bodies 9 may be embedded on both sides. Then, the elastic body 9 may be arranged at a position symmetrical on the front and back sides, or may be arranged at a position not symmetrical. Further, the elastic body 9 may have an attached structure instead of the structure embedded in the gear portion 7. When the elastic body 9 is provided on the gear portion 7, the shape of the elastic body 9 may be, for example, a triangular shape, a quadrangular shape, or a polygonal shape. Further, it may have an elliptical shape, a donut shape, or the like.

In the gear portion 7, the through hole or recess in which the elastic body 9 is embedded can be freely formed by providing a convex portion or the like corresponding to the through hole or recess in the mold when molding the gear portion 7 by casting. Can be done. Of course, after molding, a through hole or a recess may be provided by processing with a drill or the like.

As described above, it has been demonstrated that according to the present invention, it is possible to provide a balancer system gear having sufficient strength while reducing noise.

The present invention is not limited to the above-described examples, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

Specifically, in the above-described embodiment, the gear portions 5 to 8 have a rectangular shape, but may have a fan shape that spreads toward the teeth, or conversely, a fan shape that narrows toward the teeth. May be good. Further, if sufficient strength can be secured, a through hole or a recess may be provided in a part of the gear portion 7 to reduce the weight of the synchronous gear.

1,2,3a, 3b, 3c, 3d ... Synchronous gear, 4 ... Ring part, 5 ... High-strength gear part (first member), 6 ... Low-strength gear part (second member), 7 ... Gear Part, 8 ... Medium-strength gear part (third member), 9 ... Elastic body, 10 ... Teeth, 11 ... Rim.

Claims (11)

An annulus portion that is fitted to the rotating shaft and rotates together with the rotating shaft,
It has a gear portion provided on the outer circumference of the ring portion, and has.
The gear portion is divided into two or more types of members in the circumferential direction of the ring portion.
The balancer system gears are characterized in that the two or more types of members are made of fiber reinforced resins having different strengths. The gear for a balancer system according to claim 1, wherein the two or more types of members are different in the type of fiber, the filling amount, or the type of matrix resin constituting the fiber reinforced resin. The gear portion has a first member arranged in a portion of the gear portion to which the highest torque is applied, and a first member arranged in another portion of the gear portion and having a strength smaller than that of the first member. The gear for a balancer system according to claim 1 or 2 , wherein the gear is composed of two members. Further, a third member made of a fiber reinforced resin having strength between the first member and the second member is arranged between the first member and the second member. The balancer system gear according to claim 3. The gear for a balancer system according to claim 3 , wherein the Young's modulus of the first member is 70 GPa or more, and the Young's modulus of the second member is less than 10 GPa. The claim is characterized in that the Young's modulus of the first member is 70 GPa or more, the Young's modulus of the second member is less than 10 GPa, and the Young's modulus of the third member is 10 GPa or more and less than 70 GPa. The gear for the balancer system according to 4. The balancer system gear according to any one of claims 1 to 6 , wherein the fiber reinforced resin is a carbon fiber reinforced resin, a glass fiber reinforced resin, or an aramid fiber reinforced resin. The gear portion is composed of a tooth and a rim that supports the tooth.
The height h _t of the _tooth, the height of the rim when the S _R, in any one of claims 1 to 6 S R _/ h _t is equal to or less than 0.8 The gears for the balancer system described. The balancer system gear according to any one of claims 1 to 6 , further comprising an elastic body provided in the gear portion. Claim the elastic body, the disposed between the annular portion and the gear portion, the width of the elastic body when the W, W is equal to or is 0.5h _t or more The gear for the balancer system according to 9. The elastic body is provided along the outer circumference of the annular portion, and the contact surface between the elastic body and the annular portion and the contact surface between the elastic body and the gear portion have a wavy shape. The balancer system gear according to claim 10.

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