Speed change drum assembly of motorcycle

Abstract

The utility model relates to the technical field of motorcycle engines, and discloses a motorcycle speed change drum assembly which comprises a speed change drum, a gear shifting mandrel and a shifting fork, the speed change drum is sleeved and fixed on the gear shifting mandrel, a gear shifting molded line is arranged on the outer wall of the speed change drum, and the shifting fork is inserted into the gear shifting molded line. A speed change drum gear groove is formed in the outer wall of the speed change drum, a limiting ball is arranged in the speed change drum gear groove, the limiting ball vertically abuts against the interior of the speed change drum gear groove through a limiting spring, and the limiting spring is installed in a limiting bolt in a compressed mode. The device has the advantages of simplicity, reliability and compact structure.

Description

Technical Field

[0001] The utility model relates to the technical field of motorcycle engines, in particular to a motorcycle speed change drum assembly. Background Art

[0002] The motorcycle shift drum is a key component in the motorcycle transmission. It plays a vital role in the motorcycle's gear shifting process. When the shift pedal assembly is stepped on, the shift shaft will rotate, thereby driving the shift drum to work. The shift drum, through its internal mechanism (such as shift profile, convex peaks, concave peaks, etc.) and the shift fork, enables the vehicle to switch to different gears according to the driver's wishes to adapt to different driving needs.

[0003] Chinese patent document CN218625270U discloses an integrated speed shifting mechanism of a tricycle engine, including a main and secondary shaft combination and a shift fork combination, wherein the main and secondary shaft combination includes a main shaft and a secondary shaft, and the shift fork combination includes a shift drum, a shift fork shaft, a main shaft shift fork, a secondary shaft shift fork, a five-star plate, a positioning plate assembly and a positioning spring, and also includes a cover plate for detachably connecting to an engine housing, wherein the main shaft and the secondary shaft are rotatably connected to the cover plate respectively, the shift drum and the shift fork shaft are rotatably connected to the cover plate respectively, the main shaft shift fork is mounted on the shift fork shaft and cooperates with the main shaft transmission, and the secondary shaft shift fork is mounted on the secondary shaft and cooperates with the secondary shaft transmission.

[0004] Chinese patent document CN210859782U discloses a motorcycle engine shift mechanism, including a crankcase, in which a shift arm assembly and a positioning plate assembly are arranged, between the shift arm assembly and the positioning plate assembly is a five-star plate that cooperates with the shift arm assembly and the positioning plate assembly and is connected to a shift drum, at least four profiles are arranged on the outer wall of the five-star plate, at least three of which are asymmetric surfaces, the positioning plate assembly includes a positioning plate, a roller is arranged at one end of the positioning plate, and a torsion spring is arranged at the other end of the positioning plate; the roller cooperates with the profile.

[0005] This prior art has the following shortcomings: the shift drum rotates through the shift shaft, so that the shift fork moves within the shift profile to shift gears. A five-star plate and a positioning plate assembly need to be provided at one end of the shift drum to limit the position and prevent the gears from slipping out. However, the overall volume of the five-star plate and the positioning plate is large and the structure is complex, which makes the internal structure of the engine not compact enough. Utility Model Content

[0006] The utility model provides a motorcycle speed change drum assembly which makes the internal structure of the engine compact and simple in structure. The utility model comprises a speed change drum, a shift core shaft and a shift fork. The speed change drum is sleeved on and fixed to the shift core shaft. The outer wall of the speed change drum is provided with a shift profile line. The shift fork is inserted into the shift profile line. The utility model is characterized in that a speed change drum gear position groove is provided on the outer wall of the speed change drum. A limiting ball is provided in the speed change drum gear position groove. The limiting ball is vertically pressed in the speed change drum gear position groove by a limiting spring. The limiting spring is compressed and installed in a limiting bolt. When the speed change drum rotates, the limiting ball switches to different positions in the speed change drum gear position groove.

[0007] In order to facilitate the rapid switching of the power output direction of the motorcycle engine, the shift profile is arranged axially along the outer wall of the shift drum, and the shift profile includes a forward gear line groove, a medium gear line groove and a reverse gear line groove. The shift drum gear groove includes a forward gear limit groove and a reverse gear limit groove, and a protrusion is provided between the forward gear limit groove and the reverse gear limit groove.

[0008] In order to facilitate the connection and fixation between the shift core shaft and the shift drum, the shift core shaft and the shift drum are connected and fixed by a cylindrical pin.

[0009] Preferably, a cylindrical pin mounting hole 1 is provided in the middle of the shift core shaft, and a cylindrical pin mounting hole 2 is provided on the shift drum. The cylindrical pin is inserted into the cylindrical pin mounting hole 1 and the cylindrical pin mounting hole 2 at the same time to connect the shift core shaft and the shift drum.

[0010] In order to save space, ensure smooth gear shifting and ensure structural reliability, the shift fork is inserted into the gear shift profile through a guide pin.

[0011] Preferably, one end of the guide pin is inserted into the shift profile, and the other end of the guide pin is provided with a circular mounting groove, and the circular mounting groove is fixed in the guide pin mounting hole on the shift fork by a spring clip.

[0012] Preferably, the guide pin mounting hole is a raised structure, and a spring clip mounting hole is provided on the side of the guide pin mounting hole.

[0013] In order to facilitate the connection of the shift plate, a spline is provided at the end of the shift spindle.

[0014] The utility model has the following beneficial effects:

[0015] 1. The shift drum of the utility model removes the positioning and limiting mechanisms of the five-star plate and the positioning plate, and uses steel balls, limiting springs, limiting bolts and shift profiles to limit the shift angle and gear position. The steel balls, limiting springs and limiting bolts have a small volume, achieving the purpose of being simple, reliable and compact in structure. The steel balls are installed in the gear position slot of the shift drum, and play a role in fixing the gear position and preventing the gear from being disengaged under the action of the limiting springs and limiting bolts, replacing the conventional positioning plate and its positioning spring. The shifting method of the shift drum is the same as that of the conventional shift drum, which is to step on the shift pedal;

[0016] 2. The utility model meets the use requirements of forward / reverse gear switching of three-wheeled motorcycles and the requirements of space-saving engine design. The five-star plate is integrated on the speed change drum in the form of two forward and reverse gear slots. The shift core shaft and the speed change drum are fixed as a whole. Forward / reverse gear switching is often required in the use scenarios of three-wheeled motorcycles. The separate reverse gear speed change drum is more conducive to quickly switching the power output direction of the motorcycle engine. The driver's operation is simple and the overall structure is reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of an embodiment of a motorcycle speed change drum assembly of the utility model;

[0018] Figure 2 is a schematic diagram of a speed change drum;

[0019] Figure 3 is a schematic diagram of a shift fork;

[0020] Figure 4 is a schematic diagram of a guide pin;

[0021] Figure 5 A schematic diagram of the shift spindle. DETAILED DESCRIPTION

[0022] The following is further described in detail through specific implementation methods:

[0023] 1. The reference numerals in the drawings of the specification include: shift drum 1, cylindrical pin mounting hole 2 101, spindle mounting hole 102, shift spindle 2, cylindrical pin mounting hole 1 201, shift fork 3, shift drum assembly 4, shift profile 5, forward gear wire groove 501, medium wire groove 502, reverse gear wire groove 503, shift drum gear groove 6, forward gear limit groove 601, reverse gear limit groove 602, protrusion 603, steel ball 7, limit spring 8, limit bolt 9, cylindrical pin 10, spline 11, guide pin 12, circular mounting groove 13, spring clip 14, guide pin mounting hole 15, spring clip mounting hole 16, gear display boss 17.

[0024] Example 1

[0025] like Figure 1-5As shown, a motorcycle shift drum assembly includes a shift drum 1, a shift spindle 2 and a shift fork 3, wherein the shift drum 1, the shift spindle 2 and the shift fork 3 constitute a shift drum assembly 4, wherein the shift spindle 2 is installed and fixed in the spindle installation hole 102 of the shift drum 1, wherein the outer wall of the shift drum 1 is provided with a shift profile 5, wherein the shift fork 3 is inserted into the shift profile 5, wherein the outer wall of the shift drum 1 is provided with a shift drum gear slot 6, wherein a limiting ball is provided in the shift drum gear slot 6, wherein the limiting ball is a steel ball 7, wherein the steel ball 7 is vertically pressed in the shift drum gear slot 6 by a limiting spring 8, wherein the limiting spring 8 is compressed and installed in a limiting bolt 9, wherein the limiting bolt 9 is tightened on the engine housing, and when the shift drum 1 rotates, the steel ball 7 switches to different positions in the shift drum gear slot 6 to limit the shift drum 1.

[0026] The shift profile 5 is arranged along the axial direction of the outer wall of the speed change drum 1, and the shift profile 5 includes a horizontal forward gear line groove 501, an oblique middle gear line groove 502 and a horizontal reverse gear line groove 503. The forward gear line groove 501 is located obliquely above the reverse gear line groove 503, and the forward gear line groove 501 is connected to the reverse gear line groove 503 through the middle gear line groove 502. The speed change drum gear slot 6 includes a forward gear limit slot 601 and a reverse gear limit slot 602. A protrusion 603 is provided between the forward gear limit slot 601 and the reverse gear limit slot 602. The shift fork 3 switches between the forward gear line groove 501 and the reverse gear line groove 503 to realize the switching between the forward gear and the reverse gear. The steel ball 7 also switches between the forward gear limit slot 601 and the reverse gear limit slot 602, and limits the speed change drum 1 after switching to prevent the gear from being disengaged.

[0027] The shift shaft 2 is connected and fixed to the shift drum 1 by a cylindrical pin 10. A spline 11 is provided at the end of the shift shaft 2. The spline 11 is used to connect to a shift pedal. When the driver steps on the pedal, the shift shaft 2 will rotate, thereby driving the shift drum 1 to rotate for shifting. The function of the shift pedal to control the rotation of the shift shaft 2 is conventional technology and will not be elaborated here.

[0028] A cylindrical pin mounting hole 201 is provided in the middle of the shift core shaft 2, and a cylindrical pin mounting hole 101 is provided on the shift drum 1. The cylindrical pin 10 is inserted into the cylindrical pin mounting hole 201 and the cylindrical pin mounting hole 101 at the same time to connect the shift core shaft 2 and the shift drum 1. The shift core shaft 2 and the shift drum 1 are positioned by the cylindrical pin 10 and then welded and fixed.

[0029] The shift fork 3 is connected to a guide pin 12, one end of which is inserted into the shift profile 5, and the other end of which is provided with a circular mounting groove 13, which is fixed in a guide pin mounting hole 15 on the shift fork 3 by a spring clip 14, and a gear indicating boss 17 is provided on the shift fork 3.

[0030] The guide pin mounting hole 15 is a raised structure, and a spring clip mounting hole 16 is provided on the side of the guide pin mounting hole 15. The spring clip 14 is sleeved in the circular mounting groove 13 of the guide pin 12 through the spring clip mounting hole 16 to prevent the guide pin 12 from falling out.

[0031] The gear shifting process is as follows: a shifting pedal is installed at the spline 11. When the pedal is stepped on for normal gear shifting, after overcoming the compression force of the limit spring 8, the shifting mandrel 2 and the speed change drum 1 welded together rotate in a circle, and the steel ball also rotates with the speed change drum gear slot 6. Under the action of the guide pin 12 and the spring clip 14, the shift fork 3 moves axially along the shifting profile 5 on the speed change drum 1, thereby pushing the gear teeth to move axially to achieve the purpose of gear shifting. After reaching the end of the shifting profile 5, the rotation of the speed change drum 1 is restricted, and the steel ball enters the next gear slot, and fixes the gear under the action of the limit spring 8 compressed by the limit bolt 9 to prevent the gear from being disengaged. Thus, a gear shift is completed.

[0032] The above is only an embodiment of the utility model. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the utility model before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the utility model, several deformations and improvements can be made, which should also be regarded as the protection scope of the utility model, which will not affect the effect of the implementation of the utility model and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A motorcycle shift drum assembly, comprising a shift drum, a shift spindle and a shift fork, wherein the shift drum is mounted on and fixed to the shift spindle, a shift profile is provided on the outer wall of the shift drum, and the shift fork is inserted into the shift profile, characterized in that: The outer wall of the shift drum is provided with a shift drum gear slot, and a limiting ball is provided in the shift drum gear slot. The limiting ball is vertically pressed in the shift drum gear slot by a limiting spring, and the limiting spring is compressed and installed in the limiting bolt.

2. The motorcycle speed change drum assembly according to claim 1, characterized in that: The shift profile is arranged along the axial direction of the outer wall of the shift drum, and the shift profile includes a forward gear line groove, a medium gear line groove and a reverse gear line groove. The shift drum gear groove includes a forward gear limit groove and a reverse gear limit groove, and a protrusion is provided between the forward gear limit groove and the reverse gear limit groove.

3. The motorcycle speed change drum assembly according to claim 2, characterized in that: The shift core shaft is connected and fixed to the speed change drum via a cylindrical pin.

4. The motorcycle speed change drum assembly according to claim 3, characterized in that: A cylindrical pin mounting hole 1 is provided in the middle of the shift core shaft, and a cylindrical pin mounting hole 2 is provided on the shift drum. The cylindrical pin is inserted into the cylindrical pin mounting hole 1 and the cylindrical pin mounting hole 2 at the same time to connect the shift core shaft and the shift drum.

5. The motorcycle speed change drum assembly according to any one of claims 1 to 4, characterized in that: The shift fork is inserted into the shift profile via a guide pin.

6. The motorcycle speed change drum assembly according to claim 5, characterized in that: One end of the guide pin is inserted into the shift profile, and the other end of the guide pin is provided with a circular mounting groove, and the circular mounting groove is fixed in the guide pin mounting hole on the shift fork through a spring clip.

7. The motorcycle speed change drum assembly according to claim 6, characterized in that: The guide pin mounting hole is a raised structure, and a spring clip mounting hole is arranged on the side of the guide pin mounting hole.

8. The motorcycle speed change drum assembly according to claim 6 or 7, characterized in that: The end of the shift spindle is provided with a spline.

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