TW201408864A - Gear mechanism for engine balance shaft - Google Patents

Abstract

A gear mechanism for an engine balance shaft includes a driven gear set. The driven gear set includes an inner ring member fixedly sleeved on a shaft rod of the balance shaft, an outer ring member surrounding the inner ring member, and a plurality of first elastic elements embedded between the inner ring member and the outer ring member. Each of the first elastic elements has a buffering portion interconnected with the inner ring member and the outer ring member and made of a flexible material, and a core portion provided inside the buffering portion and having hardness greater than that of the buffering portion. The outer ring member has a plurality of convex teeth used for being meshed with a driving gear. The buffering portions of the first elastic elements can provide the effects of buffering and returning so as to eliminate backlash between teeth, and because the core portions have a greater hardness, they can ensure that the first elastic elements will not be damaged by shear force, thereby extending the service life of the first elastic members.

Description

Gear mechanism for the balance shaft of the engine

The present invention relates to a gear mechanism, and more particularly to a gear mechanism for a balance shaft of an engine.

1 and 2, there is an existing engine 1 having a crankcase 11 , a crankshaft 12 pivotally connected to the crankcase 11 , and a pivoting member in the crankcase 11 and the crankshaft 11 . 12 linkage balance shaft unit 2. The crankshaft 12 has at least one flywheel portion 121 for increasing inertia and a drive gear portion 122. The balance shaft unit 2 has a shaft 21 pivotally connected to the crankcase 11, a driven gear 22 fixed on the shaft 21 and meshing with the driving gear portion 122 of the crankshaft 12, and a The weight 21 of the shaft 21 extends. The driven gear 22 has an outer ring portion 221 formed with a plurality of protruding teeth, an inner ring portion 222 rotatably disposed in the outer ring portion 221 and fixed to the shaft 21, and a fitting portion a buffer group 223 between the outer ring portion 221 and the inner ring portion 222 for limiting the rotation angle of the outer ring portion 221 and the inner ring portion 222, the buffer group 223 having a plurality of rubber blocks 224 (only one angle is shown) , and a plurality of springs 225.

When the piston 12 (not shown) of the engine 1 drives the crankshaft 12 to rotate, since the driving gear portion 122 meshes with the driven gear 22, the driven gear 22 is driven to drive the shaft 21 to rotate. The weight 23 on the shaft 21 forms a rotational motion opposite to the crankshaft 12, whereby the inertia generated when the flywheel portion 121 of the crankshaft 12 is wound can be balanced, and the vibration of the entire engine 1 can be reduced.

Generally, when the driving gear portion 122 of the crankshaft 12 drives the driven gear 22 of the balance shaft unit 2, the driving gear portion 122 of the crankshaft 12 and the backlash of the driven gear 22 generate meshing gear sounds, and Backlash can easily cause the teeth of the gear to wear. However, in the above design, the inner ring portion 222 is indirectly rotated by the outer ring portion 221 of the driven gear 22 to press the buffer group 223, so that the outer ring portion 221 and the inner ring portion 222 can be relatively rotated. Eliminates backlash between teeth and reduces wear and noise.

However, the inside of the engine 1 is filled with oil and is often in a high temperature environment, so that the rubber blocks 224 are easily deteriorated and hardened, and the rubber blocks 224 are easily sheared when the outer ring portion 221 and the inner ring portion 222 are relatively rotated. The force is destroyed and the function of buffering is lost, and only the springs 225 are provided to provide a buffering effect. However, after a long time of use, the springs 225 are still cut so that the outer ring portion 221 cannot drive the inner ring portion 222. The shaft 21 of the balance shaft unit 2 cannot be rotated, and even a serious accident that causes the engine 1 to be damaged is caused. Therefore, the rubber blocks 224 must be periodically replaced, resulting in human and material consumption.

Accordingly, it is an object of the present invention to provide a gear mechanism for a balance shaft of an engine that can increase the service life.

Accordingly, the present invention is applied to a gear mechanism of a balance shaft of an engine, the balance shaft including a shaft, and a weight on the shaft, the gear mechanism including a driven gear set. The driven gear set includes a set of inner ring members fixed on the shaft, an outer ring member ringing the inner ring member, and a plurality of fittings between the inner ring member and the outer ring member and being freely rotatable First elastic element, each first The elastic member has a buffer portion connected to the inner ring member and the outer ring member and made of a flexible material, and a core portion disposed in the buffer portion and having a hardness greater than the buffer portion, the outer ring member having a plurality of A male tooth for engaging a drive gear.

The effect of the present invention is that when the inner ring member and the outer ring member move relative to each other, the buffer portion of the first elastic member can provide a buffering and recovery effect and can eliminate the backlash between the teeth, and the first The core of the elastic member has a high hardness so that the first elastic member can be prevented from being damaged by the shearing force, and the service life of the first elastic member is prolonged.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to Figures 3 and 4, there is shown a preferred embodiment of a gear mechanism 4 for a balance shaft of an engine. The balance shaft 3 includes a shaft 31 and a weight 32 on the shaft 31. The gear mechanism 4 includes a set of driven gear sets 5 disposed on the shaft 31, a fixed piece 6 covering the driven gear set 5 opposite to one side of the weight 32 and passing through the shaft 31. And a buckle 7 fastened on the shaft 31 and engaging the fixing piece 6. In this embodiment, the buckle 7 is a C-shaped buckle, but is not limited thereto.

The driven gear set 5 includes a set of inner ring members 51 fixed to the shaft 31, an outer ring member 52 ringing the inner ring member 51, and a plurality of outer ring members 51 and outer ring members 52. A first elastic member 55 that is freely rotatable and a plurality of second elastic members 56 that are fitted between the inner ring member 51 and the outer ring member 52. In this embodiment, a positioning pin 33 is inserted into the shaft 31 of the balance shaft 3, so that the inner ring member 51 cannot be rotated relative to the shaft 31, but the positioning pin 33 is not limited thereto. A chisel key is used or a bump is directly formed on the shaft 31.

The inner ring member 51 has a plurality of inner arcuate grooves 511 recessed toward the shaft 31, a plurality of inner square grooves 512 recessed toward the shaft 31, and a side formed adjacent to the weight 32 and The fixing piece 6 is spaced apart from the opposite baffle 513.

The outer ring member 52 has a plurality of convex teeth 521 for engaging with a driving gear 92, and a plurality of outer curved grooves 522 respectively corresponding to the inner curved grooves 511 and recessed away from the shaft 31. And a plurality of outer square grooves 523 respectively corresponding to the inner square groove 512 and recessed in a direction away from the shaft 31. In the present embodiment, the drive gear 92 is disposed on the crankshaft 91 of the engine and is rotatable with the crankshaft 91.

Each of the inner arcuate grooves 511 cooperates with each of the outer arcuate grooves 522 to form a first accommodating space 53 which is circular and accommodates the corresponding first elastic member 55. Each inner square groove 512 cooperates with each outer square groove 523 to form a second accommodating space 54 which is square and accommodates the corresponding second elastic member 56. The fixing piece 6 and the baffle 513 of the inner ring member 51 cooperate to close the first accommodating space 53 and the second accommodating space 54, and the first accommodating space 53 and the second accommodating space 54 are equal. The angles surround the shaft 31 at intervals.

Referring to FIG. 5 and FIG. 6 , each of the first elastic members 55 has a buffer portion 551 which is in contact with the inner ring member 51 and the outer ring member 52 and is made of a flexible material, and a buffer portion 551 is disposed in the buffer portion 551 . The inside is harder than the core 552 of the buffer portion 551. Each of the second elastic members 56 has a corresponding one The spring body 561 of the second accommodating space 54 and the two limiting pins 562 are respectively disposed at two ends of the spring body 561 at intervals. Each of the limiting pins 562 has a small diameter portion 563 that is disposed in the spring body 561, and a small diameter portion 563 that is connected to the small diameter portion 563 and has a diameter larger than the small diameter portion 563 and abuts against the edge of the spring body 561. Large diameter portion 564. Specifically, the buffer portion 551 of each of the first elastic members 55 is made of rubber, and the core portion 552 of each of the first elastic members 55 is preferably made of a metal material, and each of the second elastic members 56 is further provided. The spring body 561 is a compression spring. The fixing piece 6 and the baffle 513 of the inner ring member 51 (see FIG. 3) close the first accommodating space 53 and the second accommodating space 54 so that the first elastic element 55 and the second elastic element 56 are not Will fall out.

Referring to FIG. 4, when the driving gear 92 on the crankshaft 91 drives the driven gear set 5 to rotate, the outer ring member 52 is first driven by the driving force and is rotated relative to the inner ring member 51. At this time, the outer ring member 52 is rotated. The inner ring member 51 presses the buffer portion 551 of the first elastic member 55 and the spring body 561 of the second elastic member 56 in a dislocation position as shown in FIG. 7, so that the buffer portion 551 and the spring body 561 accumulate elasticity. The restoring force then continues to drive the inner ring member 51 to rotate, thereby rotating the shaft 31 of the balance shaft 3, and causing the weight 32 to cooperate with the movement of the crankshaft 91 to eliminate vibration. It is to be noted that, in FIG. 7, the amount of deformation of the buffer portion 551 of the first elastic member 55 is merely for convenience of explanation, and is not an actual amount of deformation.

The buffer portion 551 of the first elastic member 55 and the spring body 561 of the second elastic member 56 can release the elastic restoring force to push the outer ring member 52 in time, and eliminate the convex teeth 521 and the driving gear 92 of the outer ring member 52. The backlash generated during operation reduces the gear sound between the outer ring member 52 and the drive gear 92. with At this time, since the first elastic members 55 can be freely rotated in the first accommodating spaces 23, the positions of the buffer portions 551 are not pressed each time the outer ring members 52 and the inner ring members 51 are displaced. In the same manner, the service life of the buffer portions 551 can be relatively increased, and even if the buffer portions 551 are hardened by the influence of oil and gas and high temperature for a long time, the core portions 552 can provide greater rigidity to avoid such The cushioning portion 551 is excessively pressed and completely broken by the shearing force, so that the outer ring member 52 can still rotate the inner ring member 51.

As shown in FIG. 7, after the outer ring member 52 is displaced relative to the inner ring member 51 to press the spring bodies 561, the limit pins 562 of each second elastic member 56 are abutted against each other. Between the outer ring member 52 and the inner ring member 51, the angle at which the outer ring member 52 and the inner ring member 51 are displaced can be restricted, and the shearing force generated by the outer ring member 52 and the inner ring member 51 is prevented from being excessively large. Body 561 is over-compressed. The small-diameter portion 563 of the limiting pin 562 that is disposed in the spring body 561 can ensure that the spring body 561 can accurately expand and contract in the axial direction without undue deformation, and the limiting pin 562 also provides The higher strength can extend the service life of the spring bodies 561.

In summary, the gear mechanism 4 of the present invention is applied to the balance shaft of the engine. The first elastic member 55 of the driven gear set 5 has a core portion 552 having a higher hardness, and the second elastic member 56 has a limit pin. 562, the outer ring member 52 and the inner ring member 51 are not easily over-extruded by the first elastic member 55 and the second elastic member 56, so that the first elastic member 55 and the second elastic member 56 have a longer service life. It is not easy to be completely destroyed by the shearing force, so the object of the present invention can be achieved.

However, the above is only the preferred embodiment of the present invention, when not The scope of the invention is to be construed as being limited by the scope of the invention and the scope of the invention.

3‧‧‧Balance shaft

31‧‧‧ shaft

32‧‧‧weights

33‧‧‧Locating pin

4‧‧‧ Gear mechanism

5‧‧‧ driven gear set

51‧‧‧ Inner ring

511‧‧‧inner arc groove

512‧‧‧ square slot

513‧‧ ‧ baffle

52‧‧‧Outer ring

521‧‧‧ convex teeth

522‧‧‧outer curved groove

523‧‧‧ outer square groove

53‧‧‧First accommodation space

54‧‧‧Second accommodation space

55‧‧‧First elastic element

551‧‧‧ buffer

552‧‧‧ core

56‧‧‧Second elastic element

561‧‧ ‧spring

562‧‧‧ Limit pin

563‧‧‧ Small Trails Department

564‧‧‧The Great Trails Department

6‧‧‧Fixed tablets

7‧‧‧ buckle

91‧‧‧ crankshaft

92‧‧‧ drive gear

1 is a partial cross-sectional view showing a conventional engine; FIG. 2 is a perspective view showing a balance shaft unit of the engine; and FIG. 3 is an exploded perspective view showing a gear mechanism of the balance shaft for the engine of the present invention. Figure 4 is a cross-sectional view showing the engagement state of a driven gear set of the preferred embodiment; Figure 5 is a partially enlarged view showing the state of a first elastic member of the preferred embodiment Figure 6 is a partially enlarged view showing a second elastic member of the preferred embodiment; and Figure 7 is a schematic view showing the action of the driven gear set of the preferred embodiment.

3‧‧‧Balance shaft

31‧‧‧ shaft

32‧‧‧weights

33‧‧‧Locating pin

4‧‧‧ Gear mechanism

5‧‧‧ driven gear set

51‧‧‧ Inner ring

511‧‧‧inner arc groove

512‧‧‧ square slot

513‧‧ ‧ baffle

52‧‧‧Outer ring

521‧‧‧ convex teeth

522‧‧‧outer curved groove

523‧‧‧ outer square groove

55‧‧‧First elastic element

56‧‧‧Second elastic element

6‧‧‧Fixed tablets

7‧‧‧ buckle

Claims (7)

A gear mechanism for a balance shaft of an engine, the balance shaft comprising a shaft, and a weight on the shaft, the gear mechanism comprising: a driven gear set, comprising a set fixed on the shaft An inner ring member, an outer ring member having the inner ring member, and a plurality of first elastic members fitted between the inner ring member and the outer ring member and rotatable freely, each of the first elastic members having a a buffer portion which is in contact with the inner ring member and the outer ring member and is made of a flexible material, and a core portion which is disposed in the buffer portion and has a hardness greater than that of the buffer portion, the outer ring member has a plurality of A protruding tooth that engages the drive gear. A gear mechanism for a balance shaft of an engine according to claim 1, wherein the inner ring member of the driven gear set has a plurality of inner arcuate grooves recessed toward the shaft, the outer ring member further having a plurality of outer arcuate grooves respectively corresponding to the inner arcuate grooves and recessed away from the shaft, each of the inner arcuate grooves cooperating with each of the outer arcuate grooves to form a circular shape for receiving Corresponding to the first accommodating space of the first elastic element. A gear mechanism for a balance shaft of an engine according to claim 2, wherein the inner arcuate groove of the inner ring member and the outer arcuate groove of the outer ring member are equiangularly spaced around the shaft . A gear mechanism for a balance shaft of an engine according to claim 2, wherein the inner ring member of the driven gear set further has a plurality of inner square grooves recessed toward the shaft, the outer ring member further having a plurality of outer square grooves respectively corresponding to the inner square groove and recessed away from the shaft, each inner square groove and each outer square groove cooperate to form a square second capacity The driven gear set further includes a plurality of second elastic members respectively accommodated in the second accommodating spaces. The gear mechanism for the balance shaft of the engine according to claim 4, wherein each of the second elastic members has a spring body accommodated in the corresponding second accommodating space, and two are respectively disposed on the Limit pins at the ends of the spring body. The gear mechanism for the balance shaft of the engine according to claim 4, further comprising a fixing piece that covers the side of the counter gear and is disposed on the side of the weight, and a buckle fastened to the shaft and engaging the fixing piece, the inner ring member further having a baffle opposite to the fixing piece, the fixing piece and the baffle of the inner ring member closing the first The accommodating space and the second accommodating space. A gear mechanism for a balance shaft of an engine according to claim 5, wherein each of the limit pins of each of the second elastic members has a small diameter portion that is disposed in the spring body, and The small diameter portion is connected and has a diameter larger than the small diameter portion and abuts against a large diameter portion of the edge of the spring body.