Speed change drum

Abstract

The utility model relates to the technical field of transmission systems, in particular to a variable-speed drum which comprises a gear-shifting drum stick, a gear-shifting sleeve and a torsion spring, the gear-shifting sleeve and the torsion spring are installed on the gear-shifting drum stick, one end of the torsion spring abuts against the gear-shifting drum stick, and the other end of the torsion spring abuts against the gear-shifting sleeve. The gear shifting sleeve is provided with a first gear shifting groove. The speed change drum is small and exquisite in structure, enables gear lifting to be smooth when being used for gear lifting of a gearbox, greatly reduces the risks of abrasion and damage of the gearbox, prolongs the service life, reduces the failure rate and the use cost, and can effectively avoid the problems that an existing gearbox needs to be stopped and stepped for gear lifting, a stay wire is broken or a pawl deforms and is blocked. The speed change drum is used for driving the gear retreating piece to move to enable the gear retreating piece to move synchronously with the elastic shifting fork mechanism or driving the elastic shifting fork mechanism and the gear retreating piece to move synchronously in the lifting gear of the speed changing box, the gear shifting drum rod, the gear shifting sleeve and the torsion spring installation structure are adopted, and the gear retreating piece can be effectively prevented from being clamped when abutting against the top of the gear retreating protrusion; and smooth downshift control of the gearbox is ensured.

Description

Technical Field

[0001] This utility model relates to the field of transmission system technology, and in particular to a speed-changing drum. Background Technology

[0002] In a gearbox transmission system, a gear shifting system is needed to achieve the transmission and change of gears between different gear pairs. For example... Figure 1 As shown, in existing gearboxes, the pawl of the shift control system is located inside the countershaft. During shifting, the pawl is engaged by pulling a cable, which keeps it within the countershaft. When the gearbox is under load and needs to shift, the pawl may become stuck and unable to disengage. In this case, the pedal must be stopped and the pawl forcibly pulled out to disengage, which carries the risk of cable breakage or pawl deformation and jamming.

[0003] Given the shortcomings of the aforementioned gearboxes, there is an urgent need to provide a solution to overcome these technical problems. Utility Model Content

[0004] This invention addresses the shortcomings of existing technologies by providing a gear shift drum with a compact structure. When used in gearboxes for upshifting and downshifting, it ensures smooth gear shifting, significantly reduces the risk of gearbox wear and damage, extends service life, lowers failure rate and operating costs, and effectively avoids problems such as the need to stop and pedal to downshift, cable breakage, or ratchet deformation and jamming in existing gearboxes.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] This utility model provides a gear shift drum, including a shift drum stick, a shift sleeve mounted on the shift drum stick, and a torsion spring. One end of the torsion spring abuts against the shift drum stick, and the other end of the torsion spring abuts against the shift sleeve. The shift sleeve is provided with a first shift groove. When the shift drum stick rotates in one direction, the shift drum stick pushes the shift sleeve to rotate. When the shift drum stick rotates in another direction, the shift drum stick compresses the torsion spring, and the torsion spring compresses the shift drum stick, so that the shift drum stick pushes the shift sleeve to rotate through the torsion spring.

[0007] Furthermore, the shift drum stick is provided with a first abutment platform along its axial direction, and the shift sleeve is provided with a second abutment platform along its axial direction. One end of the torsion spring abuts against the first abutment platform, and the other end of the torsion spring abuts against the second abutment platform. When the shift drum stick rotates in one direction, the first abutment platform abuts against the second abutment platform, so that the shift drum stick pushes the shift sleeve to rotate. When the shift drum stick rotates in another direction, the first abutment platform compresses the torsion spring, and the torsion spring compresses the second abutment platform, so that the shift drum stick pushes the shift sleeve to rotate through the torsion spring.

[0008] Furthermore, the first abutment platform is provided with a first spring groove, and the second abutment platform is provided with a second spring groove; one end of the torsion spring is provided in the first spring groove, and the other end of the torsion spring is provided in the second spring groove.

[0009] Furthermore, the shift drum has an installation section and a slotted section, the shift sleeve is fitted onto the installation section, and the first abutment platform is located at the end of the slotted section.

[0010] Furthermore, a radial space for the torsion spring to abut between the first abutment platform and the second abutment platform is provided, with one end of the torsion spring located at one end of the radial space and the other end of the torsion spring located at the other end of the radial space.

[0011] Preferably, the shift drum is provided with a shift fork groove.

[0012] The beneficial effects of this utility model are:

[0013] This gear shift drum has a compact structure, which makes shifting gears smooth when used in gearboxes, greatly reducing the risk of gearbox wear and damage, extending service life, reducing failure rate and operating costs, and effectively avoiding problems such as the need to stop and pedal to downshift, cable breakage or pawl deformation and jamming in existing gearboxes.

[0014] This shift drum is used in gearbox shifting to move the downshifting component so that it moves synchronously with the elastic shift fork mechanism, or to move the elastic shift fork mechanism and the downshifting component synchronously. It adopts a shift drum rod, shift sleeve and torsion spring mounting structure, which can effectively prevent the downshifting component from getting stuck when it comes into contact with the top of the downshifting protrusion, ensuring that the gearbox can smoothly achieve downshifting operation. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an existing gearbox.

[0016] Figure 2 This is a three-dimensional structural diagram of Embodiment 1 of the present utility model.

[0017] Figure 3 This is another three-dimensional structural schematic diagram of Embodiment 1 of the present utility model.

[0018] Figure 4 This is an exploded structural diagram of Embodiment 1 of the present invention.

[0019] Figure 5 This is a schematic diagram of the application state of Embodiment 1 of this utility model.

[0020] Figure 6 This is a schematic diagram of another application state of Embodiment 1 of this utility model.

[0021] Figure 7This is a three-dimensional structural diagram of Embodiment 2 of the present invention.

[0022] Figure 8 This is another three-dimensional structural diagram of Embodiment 2 of the present invention.

[0023] Figure 9 This is an exploded structural diagram of Embodiment 2 of the present invention.

[0024] Figure 10 This is a schematic diagram of the application state of Embodiment 2 of this utility model. Detailed Implementation

[0025] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention. The present invention will be described in detail below with reference to the accompanying drawings.

[0026] Example 1.

[0027] refer to Figures 2 to 6 As shown, a gear shift drum includes a shift drum stick 01, a shift sleeve 02 mounted on the shift drum stick 01, and a torsion spring 03. One end of the torsion spring 03 abuts against the shift drum stick 01, and the other end of the torsion spring 03 abuts against the shift sleeve 02. The shift sleeve 02 is provided with a first shift groove 04. When the shift drum stick 01 rotates in one direction, the shift drum stick 01 pushes the shift sleeve 02 to rotate. When the shift drum stick 01 rotates in another direction, the shift drum stick 01 compresses the torsion spring 03, and the torsion spring 03 compresses the shift drum stick 01, so that the shift drum stick 01 pushes the shift sleeve 02 to rotate through the torsion spring 03.

[0028] In practical applications, this gear drum is used in a gearbox. The gearbox is equipped with a flexible shift fork mechanism 61, a ratchet 5, a reversing member 62, and a shift gear 3. The ratchet 5 is provided with a reversing protrusion 51 that protrudes axially. In use, the push pin of the reversing member 62 is movably disposed in the first shift groove 04.

[0029] When the transmission needs to upshift, the flexible shift fork mechanism 61 pulls the ratchet 5 from a preset position toward the shift gear 3, so that the flexible shift fork mechanism 61 drives the ratchet 5 to mesh with the shift gear 3. During this process, when the shift drum 01 rotates in one direction, the shift drum 01 pushes the shift sleeve 02 to rotate, and the shift sleeve 02 drives the downshifting component 62 to move, so that the downshifting component 62 and the flexible shift fork mechanism 61 move synchronously to realize the transmission upshifting.

[0030] When the transmission needs to downshift, the flexible shift fork mechanism 61 moves away from the shift gear 3 to a preset position. Specifically, at this time, when the shift drum 01 rotates in another direction, the shift drum 01 compresses the torsion spring 03, and the torsion spring 03 compresses the shift drum 01, causing the shift drum 01 to push the shift sleeve 02 to rotate through the torsion spring 03. The shift sleeve 02 drives the retraction member 62 to move, realizing the synchronous movement of the retraction member 62 and the flexible shift fork mechanism 61. During the continued rotation of the drive shaft 1 on which the shift gear 3 is mounted, when the retraction member 62 abuts against one side of the retraction protrusion 51 of the ratchet 5, the retraction member 62 abuts against the retraction protrusion 51 to disengage the ratchet 5 from the shift gear 3. The elastic shift fork mechanism 61 pulls the ratchet 5 back to the preset position, realizing the downshift of the transmission. When the retraction member 62 contacts the top of the retraction protrusion 51, the torsion spring 03 elastically deforms, and the retraction member 62 and the retraction protrusion 51 will not be stuck. The elastic shift fork mechanism 61 continues to move and completes the next gear shift stroke. After the contact between the retraction member 62 and the retraction protrusion 51 disappears, the retraction member 62 moves to the preset position under the elastic force of the torsion spring 03 and returns to the synchronized state with the elastic shift fork mechanism 61. This effectively avoids the retraction member 62 from getting stuck when it contacts the top of the retraction protrusion 51, ensuring that the transmission can smoothly achieve downshift control.

[0031] This shift drum is used to move the downshifting component 62 in the gearbox during upshifting and downshifting, making it move synchronously with the elastic shift fork mechanism 61. This enables the gearbox to downshift from a high gear to a low gear without unloading the load, such as when a bicycle doesn't need to stop pedaling. It effectively utilizes the circumferential driving force of the drive shaft 1 under load to downshift. Compared to existing gearboxes that require stopping the pedal to downshift, and which suffer from problems such as broken cables or deformed pawls, this makes upshifting and downshifting under load smooth. It avoids the risk of falling due to the unloading method of stopping the pedal to downshift when climbing hills, which affects the bicycle's forward balance. This greatly improves riding safety and experience. At the same time, it reduces the risk of gearbox wear and damage, extends service life, and reduces failure rate and operating costs.

[0032] This shift drum is used to move the downshifting component 62 during gear shifting. It adopts a mounting structure of shift drum rod 01, shift sleeve 02 and torsion spring 03, which can effectively prevent the downshifting component 62 from getting stuck when it comes into contact with the top of the downshifting protrusion 51, and ensure that the gearbox can smoothly achieve downshifting operation.

[0033] In this embodiment, the shift drum 01 is axially provided with a first abutment platform 011, and the shift sleeve 02 is axially provided with a second abutment platform 021. One end of the torsion spring 03 abuts against the first abutment platform 011, and the other end of the torsion spring 03 abuts against the second abutment platform 021. When the gearbox upshifts, as the shift drum 01 rotates in one direction, the first abutment platform 011 abuts against the second abutment platform 021, causing the shift drum 01 to push the shift sleeve 02 to rotate. When the gearbox downshifts, as the shift drum 01 rotates in another direction, the first abutment platform 011 compresses the torsion spring 03, and the torsion spring 03 compresses the second abutment platform 021, causing the shift drum 01 to push the shift sleeve 02 to rotate via the torsion spring 03. The specific installation structure of this shift drum is ingeniously designed, resulting in a small size, which is beneficial for reducing the size of the gearbox.

[0034] In this embodiment, the first abutment platform 011 is provided with a first spring groove 0111 and the second abutment platform 021 is provided with a second spring groove 0211; one end of the torsion spring 03 is provided in the first spring groove 0111 and the other end of the torsion spring 03 is provided in the second spring groove 0211, which facilitates the installation of the torsion spring 03 and makes the transmission drum structure stable.

[0035] In this embodiment, the shift drum 01 is provided with an installation section 012 and a slotted section 013, the shift sleeve 02 is sleeved on the installation section 012, and the first abutment platform 011 is provided at the end of the slotted section 013, which is beneficial for the installation and positioning of the shift sleeve 02 and the torsion spring 03.

[0036] In this embodiment, a radial space 05 is provided between the first abutment platform 011 and the second abutment platform 021 for the torsion spring 03 to abut. One end of the torsion spring 03 is located at one end of the radial space 05, and the other end of the torsion spring 03 is located at the other end of the radial space 05. The radial space 05 facilitates the installation of the torsion spring 03 and also allows for a certain degree of flexibility between the shift sleeve 02 and the shift drum 01, further ensuring that the retraction component 62 and the retraction protrusion 51 will not be jammed during operation.

[0037] Example 2.

[0038] refer to Figures 7 to 10 As shown, the difference between this second embodiment and the first embodiment is that the shift drum 01 is provided with a shift fork shift groove 014. In this embodiment, the drive of the elastic shift fork mechanism 61 in the first embodiment is integrated into the shift drum 01, thereby making the structure of the gearbox smaller. Specifically, the elastic shift fork mechanism 61 is provided with a shift fork pin, which is movably disposed in the shift fork shift groove 014 during use.

[0039] When the transmission needs to upshift, the shift drum 01 rotates in one direction, pushing the shift sleeve 02 to rotate. The shift drum 01 and the shift sleeve 02 simultaneously drive the elastic shift fork mechanism 61 and the unshifting component 62 to move synchronously. The elastic shift fork mechanism 61 pulls the ratchet 5 from a preset position to move closer to the shift gear 3, so that the elastic shift fork mechanism 61 drives the ratchet 5 to mesh with the shift gear 3, thereby realizing the transmission upshifting.

[0040] When the transmission needs to downshift, as the shift drum 01 rotates in the opposite direction, it compresses the torsion spring 03. The torsion spring 03 then compresses the shift drum 01, causing it to push the shift sleeve 02 to rotate via the torsion spring 03. Simultaneously, the shift drum 01 and shift sleeve 02 drive the elastic shift fork mechanism 61 and the retraction member 62 to move synchronously. The elastic shift fork mechanism 61 moves away from the shift gear 3 to a preset position. Specifically, as the drive shaft 1 housing the shift gear 3 continues to rotate, when the retraction member 62 abuts against one side of the retraction protrusion 51 of the ratchet 5, the retraction member 62 abuts against the retraction protrusion 51 to disengage the ratchet 5 from the shift gear 3. The elastic shift fork mechanism 61 pulls the ratchet 5 back to the preset position, achieving a downshift. When the retraction member 62 abuts against the top of the retraction protrusion 51, the torsion spring 03 elastically deforms, preventing the retraction member 62 and the retraction protrusion 51 from jamming. The flexible shift fork mechanism 61 and the downshifting member 62 move apart. The flexible shift fork mechanism 61 continues to move and completes the next gear shift stroke. After the contact between the downshifting member 62 and the downshifting protrusion 51 disappears, the downshifting member 62 moves to the preset position under the elastic force of the torsion spring 03 and returns to the synchronized state with the flexible shift fork mechanism 61. This effectively prevents the downshifting member 62 from getting stuck when it contacts the top of the downshifting protrusion 51, ensuring that the transmission can smoothly achieve downshifting operation.

[0041] In this embodiment, the gear drum simultaneously drives the downshifting component 62 and the elastic shift fork mechanism 61 to move synchronously during gear shifting. This enables the gearbox to downshift from a high gear to a low gear without unloading the load, allowing the bicycle to downshift without stopping the pedals. It effectively utilizes the circumferential driving force of the drive shaft 1 under load for downshifting. Compared to existing gearboxes that require stopping the pedals to downshift, and which suffer from problems such as broken cables or deformed pawls, this design ensures smooth gear shifting under load. It avoids the risk of falling due to the need to stop the pedals to downshift when climbing hills, which can affect the bicycle's balance. This significantly improves riding safety and experience. It also reduces the risk of gearbox wear and damage, extends service life, and lowers failure rate and operating costs.

[0042] This shift drum is used to drive the downshifting component 62 and the elastic shift fork mechanism 61 to move synchronously during gear shifting. It adopts a structure of shift drum rod, shift sleeve and torsion spring, which can effectively prevent the downshifting component 62 from getting stuck when it comes into contact with the top of the downshifting protrusion 51, and ensure that the gearbox can smoothly achieve downshifting operation.

[0043] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the present utility model without departing from the scope of the present utility model shall fall within the scope of the present utility model.

Claims

1. A variable speed drum, characterized in that: Includes a shift drum stick (01), a shift sleeve (02) mounted on the shift drum stick (01), and a torsion spring (03). One end of the torsion spring (03) abuts against the shift drum (01), and the other end of the torsion spring (03) abuts against the shift sleeve (02); the shift sleeve (02) is provided with a first shift groove (04); When the shift drum stick (01) rotates in one direction, the shift drum stick (01) pushes the shift sleeve (02) to rotate; when the shift drum stick (01) rotates in the other direction, the shift drum stick (01) squeezes the torsion spring (03), and the torsion spring (03) squeezes the shift drum stick (01), so that the shift drum stick (01) pushes the shift sleeve (02) to rotate through the torsion spring (03).

2. The speed-changing drum according to claim 1, characterized in that: The shift drum (01) is provided with a first abutment platform (011) in the axial direction, the shift sleeve (02) is provided with a second abutment platform (021) in the axial direction, one end of the torsion spring (03) abuts against the first abutment platform (011), and the other end of the torsion spring (03) abuts against the second abutment platform (021). When the shift drum stick (01) rotates in one direction, the first abutment (011) abuts against the second abutment (021) so that the shift drum stick (01) pushes the shift sleeve (02) to rotate; when the shift drum stick (01) rotates in the other direction, the first abutment (011) squeezes the torsion spring (03), and the torsion spring (03) squeezes the second abutment (021) so that the shift drum stick (01) pushes the shift sleeve (02) to rotate through the torsion spring (03).

3. A speed-changing drum according to claim 2, characterized in that: The first abutment platform (011) is provided with a first spring groove (0111), and the second abutment platform (021) is provided with a second spring groove (0211); One end of the torsion spring (03) is disposed in the first spring groove (0111), and the other end of the torsion spring (03) is disposed in the second spring groove (0211).

4. A speed-changing drum according to claim 2, characterized in that: The shift drum (01) is provided with an installation section (012) and a slotted section (013), the shift sleeve (02) is sleeved on the installation section (012), and the first abutment platform (011) is located at the end of the slotted section (013).

5. A speed-changing drum according to claim 2, characterized in that: A radial space (05) for the torsion spring (03) to abut between the first abutment platform (011) and the second abutment platform (021) is provided, one end of the torsion spring (03) is located at one end of the radial space (05), and the other end of the torsion spring (03) is located at the other end of the radial space (05).

6. A speed-changing drum according to any one of claims 1-5, characterized in that: The shift drum (01) is provided with a shift fork groove (014).

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