CN217736158U

CN217736158U - Balancer

Info

Publication number: CN217736158U
Application number: CN202221847973.5U
Authority: CN
Inventors: 糸贺秀树
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2022-07-18
Filing date: 2022-07-18
Publication date: 2022-11-04
Anticipated expiration: 2032-07-18

Abstract

The utility model provides a balancer. The balancer includes: a driven gear made of resin and meshed with a driving gear arranged on a crankshaft of an engine, a balance shaft inserted in an opening part of the driven gear and arranged in parallel with the crankshaft, a cover fixed on the balance shaft, and a plurality of rubber plugs held by the cover, wherein a plurality of projections are formed on one side surface of the driven gear facing the cover, insertion openings extending along a direction parallel with an axial lead of the balance shaft are formed on each rubber plug, and each projection is inserted in the insertion opening of the corresponding rubber plug, so that each rubber plug is assembled on the driven gear; the cap is provided with a plurality of holding portions, and each holding portion is in contact with an outer surface of the corresponding rubber plug extending in a direction intersecting the circumferential direction of the driven gear to hold the rubber plug. Based on above-mentioned structure, can prevent that the plug is damaged.

Description

Balancer

Technical Field

The utility model relates to a balancer.

Background

In general, a balancer is provided in a reciprocating engine mounted on a vehicle or the like. This balancer includes a balancer shaft that transmits the rotational force of the crankshaft. When the rotational force of the crankshaft is transmitted to the balance shaft, the balance shaft rotates in the opposite direction with respect to the crankshaft. Thus, the vibration force generated by the rotation of the balance shaft cancels the secondary inertia force of the engine, and the vibration of the engine can be suppressed.

Conventionally, a balancer is generally configured such that a driven gear that meshes with a drive gear provided on a crankshaft is provided on a balancer shaft, and the rotational force of the crankshaft is transmitted to the balancer shaft. In such a balancer, a driven gear made of resin is used in order to reduce the meshing sound (tooth collision sound) between gears. In the structure using the resin driven gear, a rotational force transmission mechanism using a rubber plug (Stopper) is provided for the purpose of protecting the driven gear. Specifically, a plurality of protruding portions are provided on a surface (a surface extending in a direction perpendicular to the rotation axis) of the driven gear. Rubber plugs are arranged on two sides of the protruding parts in the circumferential direction of the driven gear. The rubber plug is buckled with a cover fixed on the balance shaft. As a snap structure, a lock pin (a lock pin protruding in a direction parallel to the axis of the balance shaft) is provided on the cover, and the rubber plug is snapped into the cover by inserting the lock pin into an opening formed in the rubber plug.

Therefore, when the driven gear is acted by a rotating force, the protruding part is pressed by the rubber plug, the driven gear is protected by the elastic deformation of the rubber plug, and the pressing force is transmitted to the balance shaft through the rubber plug and the cover to rotate the balance shaft.

However, when the vibration force of the engine is large and the balance shaft resonates, a load when the protrusion collides with the rubber plug is large, and the load acts in a twisting direction of the rubber plug supported by the lock pin (a direction in which the rubber plug is twisted around the lock pin), which may cause the rubber plug to be damaged.

SUMMERY OF THE UTILITY MODEL

In view of the above, an object of the present invention is to provide a balancer capable of preventing a rubber plug from being damaged.

As a technical solution to solve the above technical problem, the utility model provides a balancer, this balancer possesses: a resin driven gear meshing with a drive gear provided on a crankshaft of an engine and having an opening, a balance shaft inserted into the opening of the driven gear and arranged parallel to the crankshaft, a cap fixed to the balance shaft, and a plurality of plugs held by the cap, wherein a plurality of protrusions protruding toward the cap are formed on a surface of the driven gear on a side facing the cap, and the plugs receive a rotational force transmitted from the drive gear to the driven gear from the protrusions, characterized in that: an insertion opening extending in a direction parallel to the axis of the balance shaft is formed in each rubber plug, and each protrusion is inserted into the insertion opening of the corresponding rubber plug, so that each rubber plug is assembled on the driven gear; the cap is provided with a plurality of holding portions, and each holding portion abuts against an outer surface of the corresponding rubber plug extending in a direction intersecting with a circumferential direction of the driven gear to hold the rubber plug.

Based on the utility model discloses an above-mentioned balancer, can prevent that the plug is damaged. Specifically, the rotational force transmitted from the driving gear to the driven gear is transmitted to the plug via the protrusion inserted in the insertion opening of the plug, and then to the balance shaft via the plug and the cap. Further, since the holding portion of the cap abuts against the outer surface of the rubber plug extending in the direction intersecting the circumferential direction of the driven gear to hold the rubber plug, the rotational force from the protruding portion does not act in the twisting direction of the rubber plug. Therefore, even when the vibration force of the engine is large and the balance shaft resonates, the rubber plug is not easily damaged.

Drawings

Fig. 1 is a sectional view showing a crankshaft of a balancer and an engine according to an embodiment of the present invention.

Fig. 2 is a sectional view of the balancer.

Fig. 3 is an exploded perspective view of the balancer.

Fig. 4 is a sectional view taken along line IV-IV in fig. 2.

Detailed Description

Hereinafter, a balancer according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a case will be described in which the present invention is applied to a balancer provided in a four-cylinder reciprocating engine mounted on a vehicle.

Fig. 1 is a sectional view showing a balancer 1 and a crankshaft 2 of an engine in the present embodiment. As shown in fig. 1, the engine includes a crankshaft 2 and a balancer 1. The balancer 1 rotates by the rotational force from the crankshaft 2, and cancels the secondary inertia force of the engine, thereby suppressing the vibration of the engine.

The crankshaft 2 is rotatably supported by a cylinder block 3 and a crank cover 4. A drive gear 21 is fixed to the crankshaft 2, and the drive gear 21 rotates with the rotation of the crankshaft 2.

The balancer 1 includes a balancer shaft 11, and the balancer shaft 11 extends parallel to the crankshaft 2 and is rotatably supported by the housing 6 located below the crankshaft 2. Further, the balance shaft 11 is assembled to the driven gear 12. The driven gear 12 meshes with the drive gear 21, and transmits the rotational force of the crankshaft 2 to the balance shaft 11. The structure for transmitting the rotational force will be described in detail later.

Further, the balance shaft 11 is provided with a weight 13 eccentric with respect to the axial center of the balance shaft 11. Accordingly, when the balance shaft 11 rotates by the rotational force from the crankshaft 2, the vibration force generated by the rotation of the balance shaft 11 cancels the secondary inertia force of the engine, and the vibration of the engine can be suppressed.

Fig. 2 is a sectional view of the balancer 1. Fig. 3 is an exploded perspective view of the balancer 1. As shown in these figures, the balancer 1 is provided with a driven gear 12 and a head cover 14 which are fitted over a balance shaft 11 and arranged along the axial direction of the balance shaft 11.

The cover 14 is fixed to the balance shaft 11, and a plurality of rubber plugs 15 are disposed inside the cover. As a structure for fixing the head cover 14, for example, an inner edge of the head cover 14 is fixed by welding to an outer surface of the balance shaft 11.

The driven gear 12 is a resin member. This can reduce the meshing sound (tooth collision sound) between the driven gear 12 and the drive gear 21.

As shown in fig. 2, the balance shaft 11 is inserted through the opening 16 of the driven gear 12, and the driven gear 12 and the balance shaft 11 are relatively movable (relatively rotatable) in the circumferential direction. That is, the inner peripheral surface 17 of the opening 16 of the driven gear 12 and the outer peripheral surface 18 of the balance shaft 11 are relatively movable in the circumferential direction. Further, lubricating oil is present between the inner peripheral surface 17 of the opening 16 of the driven gear 12 and the outer peripheral surface 18 of the balance shaft 11.

A plurality of projecting portions 12a projecting toward the cover 14 in the direction of the axis line of the balance shaft 11 are provided on a surface of the driven gear 12 on the side close to the cover 14 (the right side in fig. 2). These protrusions 12a are rectangular parallelepiped and are arranged at four positions in the circumferential direction of the driven gear 12 at equal intervals as shown in fig. 3.

As shown in fig. 2, a holding portion 12b that protrudes in a direction away from the cover 14 and is parallel to the outer peripheral surface 18 of the balance shaft 11 is formed on a surface of the driven gear 12 on a side (left side in fig. 2) facing away from the cover 14. A pair of friction dampers 12c forming an annular shape are provided between the inner peripheral surface of the holding portion 12b and the outer peripheral surface 18 of the balance shaft 11. The two friction dampers 12c are sandwiched between the inner peripheral surface of the holding portion 12b and the outer peripheral surface 18 of the balance shaft 11 and pressed by the outer peripheral surface 18 of the balance shaft 11, and suppress rotational fluctuation of the balance shaft 11 with respect to the driven gear 12 by a frictional force generated between the two friction dampers and the outer peripheral surface 18.

As shown in fig. 2, on a side of the cover 14 facing the driven gear 12, a recess 14a is formed to receive the plurality of rubber plugs 15 while receiving the plurality of protrusions 12a of the driven gear 12.

As shown in fig. 3, the plurality of rubber plugs 15 are arranged at intervals along the circumference of the balance shaft 11. Each rubber plug 15 is formed into an approximately rectangular parallelepiped shape. The rubber stoppers 15 adjacent in the circumferential direction of the driven gear 12 are connected to each other by a coupling member 15 c. In the central portion of each rubber plug 15, an insertion opening 15a extending in a direction parallel to the axis line (the chain line in fig. 3) of the balance shaft 11 is formed. The opening shape of the insertion opening 15a (the shape of a cross section perpendicular to the axis of the balance shaft 11) corresponds to (coincides with) the shape of the protruding portion 12a (the shape of a cross section perpendicular to the axis of the balance shaft 11).

Fig. 4 is a sectional view taken along line IV-IV in fig. 2. As shown in fig. 4, each protrusion 12a is inserted in the insertion opening 15a of the corresponding rubber plug 15. Thereby, each rubber plug 15 is assembled to the driven gear 12.

Meanwhile, the cap 14 is formed with a plurality of holding portions 14b for fixing the arrangement position of each plug 15 with respect to the cap 14. Each holding portion 14b is formed by recessing a part of the cover 14 toward the inner peripheral side. The length of the holding portion 14b in the circumferential direction is the same as the interval between two adjacent rubber plugs 15 in the circumferential direction. Therefore, the holding portion 14b is inserted between the adjacent two rubber plugs 15, and the arrangement position of each rubber plug 15 on the cover 14 is fixed (positioned) because the side surface of the holding portion 14b abuts against the outer surface 15b (the surface extending in the direction intersecting the circumferential direction of the driven gear 12) of the rubber plug 15.

Thus, when the driven gear 12 receives a rotational force, the protrusion 12a is pressed by the plug 15 (by the inner surface of the insertion opening 15a of the plug 15), the driven gear 12 is protected by the elastic deformation of the plug 15, and the pressing force of the protrusion 12a to the plug 15 is transmitted to the balance shaft 11 via the plug 15 and the cap 14, thereby rotating the balance shaft 11. That is, the rotational force of the crankshaft 2 is transmitted to the balance shaft 11 through the drive gear 21, the driven gear 12, the projection 12a, the plug 15, and the cap 14 in this order, and the balance shaft 11 is rotated.

As described above, since the holding portion 14b of the cap 14 abuts against the outer surface 15b of the plug 15 (the surface extending in the direction intersecting the circumferential direction of the driven gear 11) to hold the plug 15, the rotational force received from the projecting portion 12a does not act in the twisting direction of the plug 15. Therefore, even when the vibration force of the engine is large and the balance shaft 11 resonates, the rubber plug 15 is not easily damaged.

However, the present invention is not limited to the above-described embodiments, and can be modified as appropriate. For example, in the above-described embodiment, the description has been made of the case where the present invention is applied to the balancer 1 provided in the four-cylinder reciprocating engine mounted on the vehicle. However, the present invention is not limited to this, and is also applicable to a balancer provided in an engine other than the engine mounted on the vehicle. The number of cylinders of the engine is not limited to four cylinders.

In the above embodiment, the protruding portions 12a are formed at four positions of the driven gear 12. However, the present invention is not limited to this, and the number of the formation portions of the protruding portion 12a may be three or less, or five or more. In this case, the number of arranged rubber plugs 15 can be changed according to the number of the projections 12a.

In the above embodiment, the holding portion 14b is formed by recessing a part of the cover 14 toward the inner peripheral side. However, the present invention is not limited to this, and a structure may be adopted in which a protruding portion protruding from the inner surface is formed on the inner surface of the cover 14 (the surface extending in the direction perpendicular to the axial line of the balance shaft 11), and the protruding portion is brought into contact with the outer surface 15b of the plug 15 extending in the direction intersecting the circumferential direction of the driven gear 12, thereby holding the plug 15.

Claims

1. A balancer including a resin driven gear having an opening portion that meshes with a drive gear provided on a crankshaft of an engine, a balance shaft that is inserted into the opening portion of the driven gear and is arranged parallel to the crankshaft, a cover fixed to the balance shaft, and a plurality of plugs that are held by the cover, wherein a plurality of protrusions that protrude toward the cover are formed on a surface of the driven gear facing one side of the cover, and the plugs receive rotational force transmitted from the drive gear to the driven gear from the protrusions, characterized in that:

an insertion opening extending in a direction parallel to an axis of the balance shaft is formed in each rubber plug, and each protrusion is inserted into the insertion opening of the corresponding rubber plug, so that each rubber plug is assembled on the driven gear;

the cover is provided with a plurality of holding portions, and each holding portion abuts against an outer surface of the corresponding rubber plug extending in a direction intersecting with the circumferential direction of the driven gear to hold the rubber plug.