A gear change box

Abstract

The utility model provides a gear transmission belongs to the technical field of gearbox, it has solved the existing gearbox easy wear and other technical problems. The gear transmission, including the shell, rotatably installed with input shaft, output shaft and shift drum in the shell, is provided with three groups of shift grooves on the shift drum, is provided with three shift forks on the shift drum, the shift fork includes cylinder portion, fixed portion and prong portion, is equipped with fixed hole on the fixed portion, this fixed hole extends from the fixed portion and is through to the inner chamber of cylinder portion, and the axis of fixed hole and the radial line of transmission and shift drum center coincide, is provided with fixed link in the fixed hole, one end of fixed link goes into the shift groove and is matched with this shift groove, is provided with transmission between first driving gear and second driving gear, third driving gear and fourth driving gear and fifth driving gear and sixth driving gear respectively. The utility model prolongs the service life of gearbox, improves its reliability under high pressure working condition such as racing car.

Description

Technical Field

[0001] This utility model belongs to the field of gearbox technology, and specifically refers to a gearbox. Background Technology

[0002] The racing sequential manual transmission achieves fast and accurate gear shifting through a shift drum mechanism; it uses spur gears and a reinforced structure to withstand enormous torque; and it ensures reliability and stability under extreme conditions through an integrated four-wheel drive / two-wheel drive system and a forced lubrication and cooling system.

[0003] For example, in a racing sequential manual four-wheel drive gearbox with patent application number 2023228649421, the movement of the gear lever is transmitted to the shifting mechanism inside the gearbox through a linkage mechanism. This mechanism converts the linear motion of the gear lever in the forward / backward direction into a linear motion in the up / down direction. This up / down linear motion drives the shift shaft drum to rotate precisely by a fixed angle. The surface of the shift shaft drum is machined with specially shaped grooves. The end of the shift fork is embedded in these grooves. When the shift drum rotates, the contour of the grooves forces the embedded shift fork to move precisely axially along its fixed sliding rod. Existing shift forks, such as the right shift fork structure of a transmission countershaft in patent number 2017109721860, have a positioning post perpendicular to the center of the axial through-hole shaft on the left side wall of the shift fork shaft. The positioning post also has a small end protrusion. The small protrusion engages with the specially shaped groove of the shift shaft drum, and the small protrusion moves along the groove's trajectory to achieve the left / right axial movement of the shift fork.

[0004] However, in this type of structure, the small protrusion and positioning post are prone to large swing and elastic deformation when they move axially under the drive of the shift shaft drum, which in turn causes vibration and position deviation, affecting the smoothness of the shifting process and the smoothness of operation, and also aggravates the wear of the contact parts. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this utility model is to provide a gearbox. The technical problem this utility model aims to solve is to overcome the insufficient rigidity, susceptibility to wobbling and elastic deformation caused by the cantilevered positioning pin and small convex pin cooperating with the shift drum groove in traditional gearboxes, which leads to shifting vibration, positional deviation, unstable operation, and accelerated wear of contact parts.

[0006] The objective of this utility model can be achieved through the following technical solution: A gearbox includes a housing, in which an input shaft, an output shaft, and a shift drum are rotatably mounted; a driving reverse gear, a first driving gear, a second driving gear, a third driving gear, a fourth driving gear, a fifth driving gear, and a sixth driving gear are fixedly disposed on the input shaft; a driven reverse gear, a first driven gear, a second driven gear, a third driven gear, a fourth driven gear, a fifth driven gear, and a sixth driven gear are rotatably disposed on the output shaft, the driven gears being constantly meshed with their corresponding driving gears; the shift drum is provided with three sets of shift grooves, and three shift forks are sleeved on the shift drum, the shift forks being symmetrically arranged left and right, a fixing rod being provided at the center of symmetry of the shift forks, one end of the fixing rod extending into the shift groove and cooperating with the shift groove, a transmission is disposed on the output shaft, and the shift forks are used to drive the transmission.

[0007] In the aforementioned gear transmission, the shift fork comprises, from top to bottom, a cylindrical portion, a fixed portion, and a fork foot portion. The cylindrical portion is fitted onto the shift drum and covers the shift groove, and the fork foot portion is used to connect with the transmission. The fixed portion has a fixing hole that extends from the fixed portion and penetrates into the inner cavity of the cylindrical portion, and the axis of the fixing hole coincides with the radial line connecting the center of the transmission and the center of the shift drum. A fixing rod is provided in the fixing hole, and transmissions are respectively provided between the first driven gear and the second driven gear, between the third driven gear and the fourth driven gear, and between the fifth driven gear and the sixth driven gear.

[0008] In the aforementioned gearbox, the fixing rod and fixing hole are adjustable and fixed by threads.

[0009] In the aforementioned gear transmission, the transmission includes a sleeve and a shift ring. The sleeve is fixedly fitted onto the output shaft via a spline, and the shift ring is axially slidably fitted onto the outside of the sleeve via a spline. The fork portion includes an inwardly recessed fork groove, and the outer periphery of the shift ring is embedded in the fork groove.

[0010] In the aforementioned gearbox, an idler gear is rotatably connected to the housing. The driving reverse gear meshes with the idler gear, and the idler gear simultaneously meshes with the driven reverse gear, so that power is transmitted between the driving reverse gear and the driven reverse gear through the idler gear.

[0011] In the aforementioned gearbox, the active reverse gear, the first active gear, and the second active gear are integrally formed.

[0012] In the aforementioned gear transmission, a positioning ratchet portion is formed at one end of the shift drum, and seven circumferentially distributed positioning grooves are formed in the circumferential direction of the positioning ratchet portion; a pair of staggered protruding peaks are provided in the shift grooves; one of the peaks cooperates with one of the positioning grooves to jointly define a gear; wherein, a specific positioning groove cooperates with the reverse gear.

[0013] In the aforementioned gearbox, the fixing rod and the shift fork are integrally formed.

[0014] Compared with existing technologies, the technical effects of this utility model are as follows: First, by employing a fixing hole extending from the fixing part into the inner cavity of the cylindrical part, and setting a fixing rod that directly mates with the groove of the shift drum, this utility model replaces the traditional cantilevered small protruding column structure with a rigid connection that is entirely supported by the shift fork and radially aligned. This structure greatly enhances the connection rigidity between the shift fork and the shift drum, effectively suppressing the swaying and elastic deformation of the shift fork during shifting, thereby ensuring a smooth and accurate shifting process and solving the problems of vibration, positional deviation, and unsmooth operation caused by insufficient rigidity in traditional structures. Second, the axis of the fixing rod is designed to coincide with the radial line connecting the center of the transmission and the shift drum, ensuring that the force exerted by the groove of the shift drum on the fixing rod is always transmitted along the radial center of the shift fork. This centered force transmission path avoids the generation of eccentric torque, significantly reducing the contact stress and uneven wear between the fixing rod and the shift groove, as well as between the shift fork and other supporting components, thereby extending the service life of key moving parts and the entire transmission, and improving its reliability under high-pressure conditions such as racing. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the present invention.

[0016] Figure 2 This utility model is a three-dimensional object without a shell. Figure 1 .

[0017] Figure 3 This is a perspective view of the shifting component of this utility model.

[0018] Figure 4 This is a perspective view of the shift drum of this utility model.

[0019] Figure 5 This is a cross-sectional view of the shift fork of this utility model.

[0020] Figure 6 This is a perspective view of the active reverse gear, the first active gear, and the second active gear of this utility model, which are integrally formed.

[0021] Figure 7 This utility model is a three-dimensional object without a shell. Figure 2 .

[0022] Figure 8 This is a schematic diagram of the output shaft of this utility model.

[0023] Figure number markings: 1. Housing; 2. Input shaft; 21. Driven reverse gear; 22. First drive gear; 23. Second drive gear; 24. Third drive gear; 25. Fourth drive gear; 26. Fifth drive gear; 27. Sixth drive gear; 3. Output shaft; 31. Driven reverse gear; 32. First driven gear; 33. Second driven gear; 34. Third driven gear; 35. Fourth driven gear; 36. Fifth driven gear; 37. Sixth driven gear; 38. Tail gear; 4. Shift drum; 41. Shift groove; 42. Positioning ratchet part; 43. Positioning groove; 44. Peak protrusion; 5. Shift fork; 51. Cylindrical part; 52. Fixing part; 53. Fork foot part; 54. Fixing hole; 55. Fixing rod; 56. Fork groove; 6. Gearbox; 61. Sleeve; 62. Shift ring; 7. Idler gear. Detailed Implementation

[0024] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0025] It should be noted that the descriptions of "up", "down", "left", "right", "top", "bottom", etc. in this utility model are defined based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] A gearbox includes a housing 1, within which an input shaft 2, an output shaft 3, and a shift drum 4 are rotatably mounted. The input shaft 2 is fixedly equipped with a driving reverse gear 21, a first driving gear 22, a second driving gear 23, a third driving gear 24, a fourth driving gear 25, a fifth driving gear 26, and a sixth driving gear 27. The output shaft 3 is rotatably equipped with a driven reverse gear 31, a first driven gear 32, a second driven gear 33, a third driven gear 34, a fourth driven gear 35, a fifth driven gear 36, and a sixth driven gear 37, the driven gears being constantly meshed with their corresponding driving gears. The shift drum 4 has three sets of shift grooves 41, and three shift forks 5 are fitted onto the shift drum. The shift forks 5 are symmetrically arranged, with a fixing rod at the center of symmetry of each shift fork. One end of the fixing rod extends into and engages with the shift groove. A transmission is mounted on the output shaft, and the shift forks are used to drive the transmission.

[0027] The shift fork 5 comprises, from top to bottom, a cylindrical portion 51, a fixing portion 52, and a fork foot portion 53. The cylindrical portion 51 is fitted onto the shift drum and covers the shift groove 41. The fork foot portion 53 is used to connect with the transmission 6. The fixing portion 52 has a fixing hole 54, which extends from the fixing portion 52 and penetrates into the inner cavity of the cylindrical portion 51. The axis of the fixing hole 54 coincides with the radial line connecting the center of the transmission 6 and the shift drum. A fixing rod 55 is provided in the fixing hole 54 and is threadedly fixed to the fixing hole 54. One end of the fixing rod 55 extends into the shift groove 41 and engages with the shift groove 41. The transmission 6 is respectively arranged between the first driven gear 32 and the second driven gear 33, between the third driven gear 34 and the fourth driven gear 35, and between the fifth driven gear 36 and the sixth driven gear 37. The fixing rod 55 and the fixing hole 54 are adjustablely fixed by threads.

[0028] The reverse gear 21, the first drive gear 22, and the second drive gear 23 are integrally formed. An extension cylinder is also integrally formed with the reverse gear 21, the first drive gear 22, and the second drive gear 23. The extension cylinder is fixedly connected to the third drive gear 24, the fourth drive gear 25, the fifth drive gear 26, and the sixth drive gear 27 via spline engagement. A tail gear 38 is integrally formed on the output shaft 3, located on one side of the sixth driven gear 37. The transmission 6 includes a sleeve 61 and a shift ring 62. The sleeve 61 is fixedly fitted onto the output shaft 3 via spline engagement, and the shift ring 62 is axially slidably fitted onto the sleeve 61 via spline engagement. The fork foot portion 53 includes an inwardly recessed fork groove 56, and the outer periphery of the shift ring 62 is embedded in the fork groove 56.

[0029] An idler gear 7 is rotatably connected to the outer casing 1. The driving reverse gear 21 meshes with the idler gear 7, and the idler gear 7 also meshes with the driven reverse gear 31, so that power is transmitted between the driving reverse gear 21 and the driven reverse gear 31 through the idler gear 7.

[0030] One end of the shift drum 4 is formed with a positioning ratchet part 42, and seven circumferentially distributed positioning grooves 43 are formed in the circumferential direction of the positioning ratchet part 42; a pair of staggered protruding peak protrusions 44 are provided in the shift groove 41; a peak protrusion 44 cooperates with a positioning groove 43 to jointly define a gear; wherein, a specific positioning groove 43 cooperates with the reverse gear.

[0031] Engine power is transmitted to input shaft 2. The driving gears on input shaft 2 rotate accordingly, driving the driven gears on output shaft 3, which are constantly meshed with them, to idle. When a specific gear is needed, the shift drum 4 is rotated, causing the shift fork 5 to move axially.

[0032] The rotational motion of the shift drum 4 is converted into the axial motion of the shift fork 5 through the shift groove 41 on its surface. Specifically, the contour of the shift groove 41 pushes the mating fixed rod 55. Since the fixed rod 55 is rigidly fixed to the shift fork 5 through the fixed hole 54, and the axis of the fixed hole 54 coincides with the radial line connecting the center of the transmission 6 and the shift drum 4, the force is directly and centrally transmitted to the entire shift fork 5, driving the shift fork 5 to move axially along the shift drum 4. The fork foot 53 of the shift fork 5 drives the shift ring 62 to slide on the sleeve 61 through the fork groove 56. The internal spline of the shift ring 62 engages with the external spline of the sleeve 61, and its movement causes it to engage with the engaging teeth on the side of an adjacent idle driven gear, thereby locking the driven gear onto the sleeve 61. Since the sleeve 61 is fixed to the output shaft 3 by splines, power is transmitted to the output shaft 3 through the locked driven gear, and finally output through the final drive gear 38. Different positions of the shift ring 62 correspond to different driven gears, thus achieving different gear ratios. In reverse, the shift drum 4 rotates to a specific angle and engages with the transmission 6 associated with the driven reverse gear 31 via the corresponding shift fork 5, and power is transmitted in the reverse direction via the idler pulley 7.

[0033] By employing a fixing hole 54 extending from the fixing part 52 into the inner cavity of the cylindrical part 51, and a fixing rod 55 directly engaging with the groove of the shift drum 4, this invention replaces the traditional cantilevered small protruding column structure with a rigid connection radially aligned and entirely supported by the shift fork 5. This structure significantly enhances the connection rigidity between the shift fork 5 and the shift drum 4, effectively suppressing the swaying and elastic deformation of the shift fork 5 during shifting, thereby ensuring a smooth and accurate shifting process and solving the problems of vibration, positional deviation, and unsmooth operation caused by insufficient rigidity in traditional structures. The axis of the fixing rod 55 is designed to coincide with the radial line connecting the center of the transmission 6 and the center of the shift drum 4, ensuring that the force exerted by the groove of the shift drum 4 on the fixing rod 55 is always transmitted along the radial center of the shift fork 5. This aligned force transmission path avoids the generation of eccentric torque, significantly reducing the contact stress and uneven wear between the fixing rod 55 and the shift groove 41, as well as between the shift fork 5 and other supporting components, thereby extending the service life of key moving parts and the entire transmission, and improving its reliability under high-pressure conditions such as racing.

[0034] Another alternative to the connection structure between the fixed rod 55 and the shift fork 5 described above is to integrally mold the fixed rod 55 and the shift fork 5 to enhance the strength between them.

[0035] The above embodiments are merely preferred embodiments of the present utility model and are not intended to limit the scope of protection of the present utility model. Therefore, all equivalent changes made to the structure, shape, and principle of the present utility model should be covered within the scope of protection defined by the claims of the present utility model.

Claims

1. A gearbox, comprising a housing (1), wherein an input shaft (2), an output shaft (3), and a shift drum (4) are rotatably mounted within the housing (1); a driving reverse gear (21), a first driving gear (22), a second driving gear (23), a third driving gear (24), a fourth driving gear (25), a fifth driving gear (26), and a sixth driving gear (27) are fixedly disposed on the input shaft (2); a driven reverse gear (31), a first driven gear (32), a second driven gear (33), a third driven gear (34), a fourth driven gear (35), a fifth driven gear (36), and a sixth driven gear (37) are rotatably disposed on the output shaft (3), wherein the driven gears are constantly meshed with the corresponding driving gears; characterized in that: The shift drum (4) is provided with three sets of shift grooves (41), and the shift drum (4) is fitted with three shift forks (5). The shift forks (5) are arranged symmetrically on the left and right. A fixing rod (55) is provided at the center of symmetry of the shift fork (5). One end of the fixing rod (55) extends into the shift groove (41) and cooperates with the shift groove (41). A transmission (6) is provided on the output shaft (3), and the shift fork (5) is used to drive the transmission (6).

2. The gearbox according to claim 1, characterized in that: The shift fork (5) comprises, from top to bottom, a cylindrical part (51), a fixed part (52), and a fork foot part (53). The cylindrical part (51) is fitted onto the shift drum (4) and covers the shift groove (41). The fork foot part (53) is used to connect with the transmission (6). The fixed part (52) is provided with a fixing hole (54). The fixing hole (54) extends from the fixing part (52) and penetrates into the inner cavity of the cylindrical part (51). The axis of the fixing hole (54) coincides with the radial line connecting the center of the transmission (6) and the shift drum (4). A fixing rod (55) is provided in the fixing hole (54). The transmission (6) is respectively provided between the first driven gear (32) and the second driven gear (33), between the third driven gear (34) and the fourth driven gear (35), and between the fifth driven gear (36) and the sixth driven gear (37).

3. A gearbox according to claim 2, characterized in that: The fixing rod (55) and fixing hole (54) are adjustable and fixed by threads.

4. A gearbox according to claim 2, characterized in that: The transmission (6) includes a sleeve (61) and a gear ring (62). The sleeve (61) is fixedly fitted onto the output shaft (3) by a spline. The gear ring (62) is axially slidably fitted onto the outside of the sleeve (61) by a spline. The fork foot (53) includes an inwardly recessed fork groove (56). The outer periphery of the gear ring (62) is embedded in the fork groove (56).

5. A gearbox according to claim 1, characterized in that: An idler gear (7) is rotatably connected to the outer casing (1). The driving reverse gear (21) meshes with the idler gear (7), and the idler gear (7) meshes with the driven reverse gear (31) at the same time, so that power is transmitted between the driving reverse gear (21) and the driven reverse gear (31) through the idler gear (7).

6. A gearbox according to any one of claims 1 to 5, characterized in that: The active reverse gear (21), the first active gear (22), and the second active gear (23) are integrally formed.

7. A gearbox according to any one of claims 1 to 5, characterized in that: One end of the shift drum (4) is formed with a positioning ratchet part (42), and the positioning ratchet part (42) has seven circumferentially distributed positioning grooves (43) in the circumferential direction; a pair of staggered protruding peaks (44) are provided in the shift groove (41); one of the peaks (44) cooperates with one of the positioning grooves (43) to jointly define a gear; wherein, a specific positioning groove (43) cooperates with the reverse gear.

8. A gearbox according to claim 1, characterized in that: The fixing rod (55) and the shift fork (5) are integrally formed.

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