TWI880660B - Chain guide of rear derailleur - Google Patents

Abstract

A chain guide of a bicycle includes an arm, a first wheel, and a second wheel. The arm has a rail and a stop member, and the first wheels is pivoted on the arm. The second wheel has a gear ring, a core, and an elastic member. The gear ring has a hole at a center to receive the core, and the core engages the rail of the arm to be moved along the rail. The core has a slot, and the stop member is inserted into the slot. The elastic member is received in the slot and has opposite ends urging the core and the stop member of the arm. The second wheel is moved by a chain, and the elastic member is deformed when the chain is being switched between gear discs, and the second wheel is returned by a recovering force of the elastic member when the chain has completed the switching procedure.

Description

Rear derailleur guide chain device

The present invention relates to bicycles, and in particular to a guide chain device for a rear derailleur.

Generally, the speed changer of a bicycle is operated by the rider to make the chain shift between gears of different sizes, while the chain guide is installed on the rear derailleur. After the chain is shifted to gears of different sizes, the relative angle between the chain guide and the rear derailleur is changed to adjust the tension of the chain, so that the bicycle can still be transmitted smoothly after the gear shift.

However, the conventional method is of limited help in the smoothness of the chain switching. When the resistance of the chain is large when it is chained up and down, it will affect the smoothness of riding and even cause the failure of chaining up and down. In addition, when the chain is switched to a large-sized sprocket, the distance between a guide wheel of the chain guide and the large-sized sprocket is quite close, which will cause the chain surface of the chain to be skewed. The skewed chain surface can easily cause the failure of chaining up and down.

The main purpose of the present invention is to provide a guide chain device for a rear transmission, which can make the gear shifting process smoother.

In order to achieve the above-mentioned invention purpose, the invention provides a guide chain device for a rear transmission, comprising an arm having a track and a stopper; a first guide wheel pivotally arranged at one end of the arm; and a second guide wheel having a gear ring, a wheel center and an elastic member; the gear ring has an axial hole in the center and a plurality of teeth on the outer periphery; the wheel center is provided with a plurality of teeth on the outer periphery; The axial hole provided in the gear ring enables the gear ring to rotate relative to the wheel center; the wheel center has a connecting portion, which is combined with the track of the support arm, so that the wheel center is connected to the support arm and can move along the track; the wheel center is provided with a guide groove, and the stopper of the support arm passes through the guide groove; the elastic member is accommodated in the guide groove, with one end abutting against the stopper and the other end abutting against the wheel center.

Thus, a chain engaged with the teeth of the gear ring will act on the second guide wheel when shifting, causing the second guide wheel to move and causing the elastic member to deform; when the force of the chain disappears, the elastic member will generate a restoring force to restore the second sprocket to its initial state.

In one embodiment, the connecting portion of the wheel center has a groove; the track of the support arm has two parallel protrusions; the two protrusions of the track are accommodated in the groove of the connecting portion.

In one embodiment, the bottom side surface of the groove of the connecting portion has the guide groove.

In one embodiment, the second guide wheel further includes a bearing disposed between the wheel center and the gear ring; a baffle is disposed in the shaft hole of the gear ring and abuts against the bearing.

In one embodiment, a baffle is provided on the outer circumference of the wheel center, abutting against the bearing.

In one embodiment, a column is provided in the guide groove of the wheel center, one end of the column is connected to the side wall of the guide groove, and the other end is a free end; the elastic member is sleeved on the column.

In one embodiment, the second guide wheel further includes a wheel cover, which is disposed in the axial hole of the gear ring and covers the wheel center.

In one embodiment, the wheel cover has an opening corresponding to the stopper of the arm, for a locking member to pass through and lock the wheel cover to the stopper.

The guide chain device of the rear transmission provided by the present invention can generate a displacement of the second guide wheel at the moment of gear shifting through the action of the elastic member, making the gear shifting process smoother, reducing wear, and reducing the occurrence of chain disengagement and tooth slippage.

The following is a list of preferred embodiments based on the purpose, efficacy and structural configuration disclosed by the present invention, and is described in detail with accompanying drawings.

10: Arm

12: First guide wheel

14: Second guide wheel

16: First end

18: Second end

20: Axle

22: Track

24: Stopper

26: Screw hole

28: Teeth

30: Rings

32: Bearings

34: Chakra

36: Elastic parts

38: Wheel cover

40: Axle hole

42: Teeth

44:Blocking edge

46: Center hole

48:Connection part

50:Block ring

52: Guide groove

54: Column

56: Open mouth

58: Lock firmware

60:Chain

Figure 1 is a three-dimensional diagram of a preferred embodiment of the present invention.

Figure 2 is a disassembled diagram of a preferred embodiment of the present invention.

Figure 3 is a disassembled view of the second guide wheel of a preferred embodiment of the present invention.

Figure 4 is a cross-sectional view taken along line 4-4 in Figure 1.

Figure 5 is a partial front view of a preferred embodiment of the present invention, showing the movement of the second guide wheel during gear shifting.

Please refer to FIG. 1, a preferred embodiment of the present invention provides a guide chain device for a rear derailleur, which is connected to a rear derailleur (not shown), and includes an arm 10, a first guide wheel 12 and a second guide wheel 14, wherein the first guide wheel 12 and the second guide wheel 14 are respectively pivoted at the two ends of the arm 10.

As shown in FIG. 2, the arm 10 is an elongated plate having a first end 16 and a second end 18. A wheel axle 20 is provided at a predetermined position on one side thereof near the first end 16; and a track 22 is provided at a predetermined position on the same side near the second end 18. In this embodiment, the track 22 has two elongated protrusions. The two protrusions are arranged in a mirror image, parallel and at a predetermined distance. A stopper 24 is provided between the two protrusions. In this embodiment, the stopper 24 is a column extending outward from the side of the arm 10. In addition, a screw hole 26 is provided at the outer end of the stopper 24.

The outer periphery of the first guide wheel 12 has a plurality of teeth 28. The first guide wheel 12 is connected to the axle 20 of the support arm 10 and can rotate freely relative to the support arm 10.

As shown in FIG. 3 and FIG. 4, the second guide wheel 14 has a gear ring 30, a bearing 32, a wheel center 34, an elastic member 36 and a wheel cover 38. The gear ring 30 has an axial hole 40 in the center and a plurality of teeth 42 on the outer periphery. A baffle 44 is provided at one end of the axial hole 40, which is a flange extending from the side wall of the axial hole 40 to the center, so that the hole diameter of the axial hole 40 at the end with the baffle 44 is smaller than that at the other end. The bearing 32 has a center hole 46 in the center. The wheel center 34 is a circular block, and a connecting portion 48 is provided on one end surface thereof, which is in a complementary state with the track 22 of the support arm 10. In the present embodiment, the connecting portion 48 is a groove and is open on the outer circumference at both ends of the wheel center 34. A baffle 50 is provided on the outer circumference of the wheel center 34, which is a ring extending outward from the outer circumference and is located on the opposite side relative to the connecting portion 48. The wheel center 34 is further provided with an elongated guide groove 52, which is located on the bottom side of the groove of the connecting portion 48 and is open on both end surfaces of the wheel center 34. A column 54 is provided in the guide groove 52, one end of which is connected to the side wall of the guide groove 52 along one end of its long axis, and the other end is a free end. In other words, the length of the column 54 is less than that of the guide groove 52. In the present embodiment, the length of the column 54 is less than half of the length of the guide groove 52. The bearing 32 is disposed in the shaft hole 40 of the gear ring 30 and abuts against the baffle 44, and the wheel center 34 is installed in the center hole 46 of the bearing 32, so that the baffle 50 abuts against the bearing 32, so that the gear ring 30 can rotate freely relative to the wheel center 34. The connecting portion 48 of the wheel center 34 is combined with the track 22 of the support arm 10, so that the wheel center 34 can move along the track 22. The stopper 24 passes through the guide slot 52 and is a predetermined distance away from the free end of the column 54. The elastic member 36 is a coil spring in this embodiment, which is sleeved on the column 54, with one end abutting against the column 54. The initial position of the second guide wheel 14 is when the column 54 abuts against one end of the guide groove 52. The wheel cover 38 is disposed in the shaft hole 40 of the gear ring 30, covering the bearing 32 and the wheel center 34. The wheel cover 38 is provided with an opening 56 corresponding to the screw hole 26 of the stopper 24, for a locking member 58 (a bolt in this embodiment) to pass through the opening 56 of the wheel cover 38 and lock to the screw hole 26 of the stopper 24 of the support arm 10, so as to stably connect the second guide wheel 14 to the support arm 10 and allow the gear ring 30 to rotate freely.

The guide chain device of this embodiment is connected to a rear derailleur (not shown), and a chain 60 passes through the first guide wheel 12 and the second guide wheel 14, and engages with the teeth 28, 42 respectively. When shifting, the chain 60 generates a force applied to the first guide wheel 12, changing the angle of the support arm 10 to maintain the tension of the chain 60. At the same time, the chain 60 also applies a force to the second guide wheel 14, as shown in FIG. 5, so that the second guide wheel 14 moves to the left in the figure and compresses the elastic member 36. The movement of the second guide wheel 14 allows the chain 60 to shift gears more smoothly and reduce the occurrence of chain disengagement or tooth slippage. When the chain 60 completes the shifting, the force exerted by the chain 60 on the second guide wheel 14 is reduced. At this time, the elastic member 36 will generate a restoring force to push the second guide wheel 14 back to the initial state and continue to operate.

It should be specially pointed out here that the elastic member can not only be set on the second guide wheel (the guide wheel close to the transmission). In practice, the first guide wheel (the guide wheel far from the transmission) can also be provided with the elastic member, or both guide wheels of the guide chain device are provided with the elastic member.

The above embodiments are only for illustrative purposes to illustrate the technology and its effects of the present invention, and are not intended to limit the present invention. Anyone skilled in the art can modify and change the above embodiments without violating the technical principles and spirit of the present invention. Therefore, the scope of protection of the present invention shall be as described below in the scope of the patent application.

14: Second guide wheel

30: Rings

32: Bearings

34: Chakra

36: Elastic parts

38: Wheel cover

40: Axle hole

42: Teeth

44:Blocking edge

46: Center hole

48:Connection part

50:Block ring

52: Guide groove

54: Column

56: Open mouth

58: Lock firmware

Claims (7)

A guide chain device for a rear transmission includes: an arm having a track and a stopper; a first guide wheel pivotally mounted at one end of the arm; and a second guide wheel having a gear ring, a wheel center, and an elastic member; the gear ring has an axial hole at the center and a plurality of teeth at the outer periphery; the wheel center is mounted in the axial hole of the gear ring so that the gear ring can rotate relative to the wheel center; the wheel center has a connecting portion that is combined with the track of the arm so that the wheel center is connected to the arm and can move along the track; the wheel center is provided with a guide groove, and the stopper of the arm is provided with a guide groove. The stopper passes through the guide groove; the elastic member is accommodated in the guide groove, with one end abutting against the stopper and the other end abutting against the wheel center; thereby, a chain engaged with the teeth of the gear ring will act on the second guide wheel during gear shifting, causing the second guide wheel to move and causing the elastic member to deform; when the force of the chain is reduced, the elastic member will generate a restoring force to restore the second sprocket to its initial state; wherein the connecting portion of the wheel center has a groove; the track of the support arm has two parallel protrusions; the two protrusions of the track are accommodated in the groove of the connecting portion. The guide chain device of the rear transmission as described in claim 1, wherein the bottom side surface of the groove of the connecting portion has the guide groove. The guide chain device of the rear transmission as described in claim 1, wherein the second guide wheel further includes a bearing disposed between the wheel center and the gear ring; a baffle is disposed in the shaft hole of the gear ring, abutting against the bearing. The guide chain device of the rear transmission as described in claim 3, wherein a baffle ring is provided on the outer peripheral surface of the wheel center, abutting against the bearing. As described in claim 1, the guide chain device of the rear transmission, wherein a column is provided in the guide groove of the wheel center, one end of the column is connected to the side wall of the guide groove, and the other end is a free end; the elastic member is sleeved on the column. The guide chain device of the rear transmission as described in claim 1, wherein the second guide wheel further includes a wheel cover, which is arranged in the axial hole of the gear ring and covers the wheel center. A guide chain device for a rear transmission as described in claim 6, wherein the wheel cover has an opening corresponding to the stopper of the support arm, for a locking member to pass through and lock the wheel cover to the stopper.

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