Gear shifting mechanism and middle transmission

Abstract

The utility model relates to the technical field of transmissions, and provides a gear shifting mechanism and a middle transmission. The gear shifting mechanism is used for controlling locking and separation of the shaft and one or more gears installed on the shaft. The gear shifting mechanism comprises a sleeve, a pawl and an elastic piece. The pawl and the elastic piece are installed in the shaft and located on the outer side of the sleeve. A gear shifting groove is formed in the sleeve, and the sleeve is used for rotating under the driving of external force; the elastic piece is used for abutting against one end of the pawl to enter the gear shifting groove when the sleeve rotates till one end of the pawl is located above the gear shifting groove, so that the other end of the pawl is tilted to lock the shaft and the gear, and the sleeve is used for being tangent to the pawl to jack up one end of the pawl when one end of the pawl is away from the gear shifting groove, so that the other end of the pawl is reset. The gear and the shaft are separated. Due to the fact that the force applied to the pawl is larger when the sleeve rotates, gear shifting can be achieved under the pawl load state.

Description

Technical Field

[0001] The utility model relates to the technical field of transmissions, in particular to a gear shift mechanism and a mid-mounted transmission. Background Art

[0002] In a mid-mounted transmission, the first gear and shaft are locked and separated by a shift mechanism, enabling gear shifting. When multiple first gears are mounted on a shaft, different first gears correspond to different gear positions, allowing the transmission to shift between different gears. Existing shift mechanisms typically require the first gear to be stopped before shifting, meaning they cannot shift under load, impacting the user's shifting experience. Utility Model Content

[0003] The purpose of the utility model is to provide a gear shift mechanism and a mid-mounted transmission, aiming to solve the problem in the prior art that the gear shift mechanism cannot shift gears under load.

[0004] In the first aspect, the present application provides a shifting mechanism for controlling the locking and separation of a shaft and one or more gears mounted on the shaft; the shifting mechanism comprises: a sleeve, a pawl and an elastic member; the sleeve is located inside the shaft, the pawl and the elastic member are installed inside the shaft and located outside the sleeve; a shifting groove is provided on the sleeve, and the sleeve is used to rotate under the drive of an external force; the elastic member is used to press one end of the pawl into the shifting groove when the sleeve rotates to one end of the pawl is located above the shifting groove, so that the other end of the pawl is tilted to lock the shaft and the gear, and the sleeve is used to be tangent to the pawl when one end of the pawl is away from the shifting groove to lift one end of the pawl, so that the other end of the pawl is reset to separate the gear and the shaft.

[0005] In one embodiment, the shift groove is an oblique groove whose center line is not parallel to or perpendicular to the center axis of the sleeve.

[0006] In one embodiment, the shifting mechanism further includes a sliding member, which is passed through the inclined groove and is axially slidably installed in the shaft, and is used to make the sliding member and the sleeve rotate synchronously with the shaft when no gear shifting is required, and to drive the sleeve and the shaft to rotate relative to each other through axial movement when gear shifting is required.

[0007] In one embodiment, the shift mechanism further includes a screw, a nut, and a first fixing member disposed in the sleeve, the nut being mounted on the screw, the first fixing member being used to limit the nut in the circumferential direction, and the screw being used to drive the nut to move axially by rotating, thereby driving the sliding member to move axially.

[0008] In one embodiment, at least one end of the screw extends out of the shaft to connect to a drive assembly of the screw.

[0009] In one embodiment, the first fixing member includes a plurality of fixing rods, and both ends of the fixing rods are mounted on the housing where the shift mechanism is located.

[0010] In one embodiment, a plurality of the fixing rods are passed through the nut.

[0011] In one embodiment, the number of the shift slots is 2.

[0012] In one embodiment, the shift mechanism further includes a planetary gear assembly for driving the sleeve to rotate.

[0013] In second aspect, the present application provides a mid-mounted transmission, comprising a first shaft, a plurality of first gears circumferentially rotatably mounted on the first shaft, a second shaft parallel to the first shaft, a plurality of second gears mounted on the second shaft, and a shifting mechanism as described in the first aspect above, each first gear being engaged with a corresponding second gear; the shifting mechanism being used to be installed in the first shaft to control the locking and separation of the first shaft and any one or more of the first gears; the first gear locked with the first shaft being used to rotate under the drive of the first shaft, so as to drive the second shaft to rotate through the second gear engaged with the first gear.

[0014] The shift mechanism for a mid-mounted transmission provided by the present invention has the following beneficial effects: the shift mechanism includes a sleeve, a pawl, and an elastic member. The sleeve is provided with a shift slot. When a shift is required, the relative position of the shift slot and the pawl is changed by rotating the sleeve to achieve the clutching of the pawl with the first shaft and the gear. Because the sleeve exerts a greater force on the pawl when rotating, shifting can be achieved while the pawl is loaded. Furthermore, by rotating the sleeve to change the clutching state of the pawl, the control accuracy of the pawl is improved, thereby enhancing the reliability of the shift mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art.

[0016] Figure 1 A schematic diagram of the shifting principle of the shifting mechanism provided in an embodiment of the present utility model;

[0017] Figure 2 A schematic diagram of the assembly of the shift mechanism on the shaft provided by an embodiment of the present utility model;

[0018] Figure 3 A schematic diagram of a shift mechanism provided in an embodiment of the present utility model;

[0019] Figure 4 A schematic diagram of the principle of a screw driving a sliding member to move according to an embodiment of the present utility model;

[0020] Figure 5 A schematic diagram of a mid-mounted transmission provided in an embodiment of the present utility model.

[0021] Among them, the reference numerals in the figures are:

[0022] 10. Shift mechanism; 11. Sleeve; 111. Shift groove; 12. Pawl; 13. Sliding member; 14. Elastic member; 15. Screw; 16. Nut; 17. First fixing member; 171. Fixing rod; 18. Second fixing member; 20. Shaft; 21. First shaft; 22. Second shaft; 23. Limiting hole; 30. Gear; 31. First gear; 32. Second gear. DETAILED DESCRIPTION

[0023] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment" or "in some embodiments" appear in various places throughout this specification, not all references are to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0025] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features.

[0027] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, indirect connection through an intermediate medium, internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0028] Please refer to Figure 1-4 Now, the shift mechanism in the embodiment of the present utility model is described.

[0029] The shift mechanism 10 is mounted in a mid-mount transmission and controls the locking and disengagement of a shaft 20 and one or more gears 30 mounted on the shaft 20. A mid-mount transmission comprises two parallel shafts, one of which is connected to a bicycle disc. The shift mechanism can be mounted on either shaft. The shift mechanism 10 includes: a sleeve 11, a pawl 12 and an elastic member 14; the sleeve 11 is located in the shaft 20, and the pawl 12 and the elastic member 14 are installed in the shaft 20 and are located on the outside of the sleeve 11; a shift groove 111 is opened on the sleeve 11, and the sleeve 11 is used to rotate under the drive of an external force; the elastic member 14 is used to press one end of the pawl 12 into the shift groove 111 when the sleeve 11 rotates to the point where one end of the pawl 12 is located above the shift groove 111, so that the other end of the pawl 12 is tilted to lock the shaft 20 and the gear 30, and the sleeve 11 is used to be tangent to the pawl 12 when one end of the pawl 12 is away from the shift groove 111 to lift one end of the pawl 12, so that the other end of the pawl 12 is reset to separate the gear 30 and the shaft 20.

[0030] Specifically, the two ends of the elastic member 14 respectively conflict with the pawl 12 and the shaft 20. For example, a positioning member is provided on the shaft 20, and the elastic member 14 is mounted on the positioning member and its two ends conflict with the pawl 12 and the shaft 20 respectively. The elastic member 14 applies a force toward the side of the sleeve 11 on one end of the pawl 12. When the sleeve 11 rotates, the relative position of the pawl 12 and the shift groove 111 changes. When the sleeve 11 rotates until one end of the pawl 12 is located above the shift groove 111, the elastic member 14 presses one end of the pawl 12, causing one end of the pawl 12 to enter the shift groove 111, thereby causing the other end of the pawl 12 to tilt up, and then causing the other end of the pawl 12 to engage in the gear 30, thereby locking the gear 30 and the shaft 20 to achieve gear shifting. When the sleeve 11 rotates until one end of the pawl 12 is away from the shift groove 111, one end of the pawl 12 contacts the sleeve 11, that is, the sleeve 11 is tangent to one end of the pawl 12, so that the sleeve 11 lifts one end of the pawl 12, and the other end of the pawl 12 is reset, thereby disengaging the pawl 12 from the gear 30, separating the gear 30 from the shaft 20, and achieving downshifting. Because the force applied to the pawl 12 by the sleeve 11 is greater when it rotates, it is possible to shift gears while the pawl 12 is loaded. At the same time, by rotating the sleeve 11 to change the clutch state of the pawl 12, the control accuracy of the pawl 12 can be improved, thereby improving the reliability of the shift mechanism 10. At the same time, through the above-mentioned structural design, the pawl 12 engages gears under the elastic force of the elastic member 14 and de-gears under the thrust of the sleeve 11, thereby achieving soft-connected engagement and hard-connected de-gearing, thereby improving the reliability of the shifting.

[0031] It can be understood that when multiple gears 30 are installed on the shaft 20, the shift mechanism 10 includes multiple pawls 12, each pawl corresponds to an elastic member 14, and each pawl 12 corresponds to a gear 30, for controlling the locking and separation of the corresponding gear 30 and the shaft 20.

[0032] It can be understood that the portion outside the shift groove 111 in the sleeve 11 is used to support the pawl that does not need to lock the gear 30. That is, the pawl 12 that does not shift contacts the sleeve 11 and is in a reset state.

[0033] In one embodiment, multiple pawls 12 are arranged along the axial direction of the sleeve 11, and the shift groove 111 is an inclined groove whose center line is not parallel to or perpendicular to the center axis of the sleeve 11. By rotating the sleeve 11, different pawls 12 can be located above the shift groove 111, thereby achieving different clutch states of different pawls 12.

[0034] In another embodiment, multiple pawls 12 are arranged along the axial and circumferential directions of the sleeve 11, and the shift groove 111 is a straight groove whose center line is parallel to the center axis of the sleeve 11. By rotating the sleeve 11, the shift groove 111 can be rotated to the bottom of different pawls 12, thereby achieving different clutch states of different pawls 12.

[0035] In one embodiment, the shift groove 111 is an oblique groove. The shift mechanism 10 further includes a slider 13, which is disposed within the oblique groove and axially slidably mounted within the shaft 20. The slider 13 is configured to rotate synchronously with the shaft 20 when not shifting, and to drive the sleeve 11 to rotate relative to the shaft 20 by axial movement when shifting is required. Specifically, because the slider 13 is disposed within the oblique groove, axial movement of the slider 13 causes the slider 13 to move within the oblique groove, thereby driving the sleeve 11 to rotate. When shifting is required, axial movement of the slider 13 causes the sleeve 11 to rotate relative to the shaft 20, thereby changing the relative position of the oblique groove and the pawl 12 and achieving a shift. The shaft 20 circumferentially constrains the slider 13, allowing it to rotate synchronously with the shaft 20. Because the slider 13 is disposed within the oblique groove, it does not move axially when not shifting, driving the sleeve 11 to rotate synchronously with the shaft 20. Since the pawl 12 and the elastic member 14 are mounted in the shaft 20, the pawl 12 and the elastic member 14 also rotate synchronously with the shaft 20. By inserting the slider 13 into the inclined slot, the axial movement of the slider 13 can be converted into the circumferential rotation of the sleeve 11, thereby simplifying the structure of the driving assembly of the slider 13.

[0036] In order to achieve the axially slidable installation of the sliding member 13 in the shaft 20 , a boss may be provided on the sliding member 13 , the boss passing through the inclined slot and installed in the groove on the inner side of the shaft 20 .

[0037] In one embodiment, the edge of the shift groove 111 is provided with a slope extending in a direction perpendicular to the center line of the shift groove 11 , thereby increasing the exit speed of the pawl 12 from the shift groove 111 and further increasing the shifting speed.

[0038] In one embodiment, the shift mechanism 10 further includes a screw 15, a nut 16, and a first fixing member 17 disposed within the sleeve 11. The nut 16 is mounted on the screw 15, and the first fixing member 17 is used to limit the nut 16 in the circumferential direction. The screw 15 is used to drive the nut 16 to move axially by rotating, thereby driving the sliding member 13 to move axially. Specifically, because the nut 16 cannot rotate circumferentially, when the screw 15 is rotated, the nut 16 can only move axially, and the nut 16 limits the sliding member 13 in the axial direction. Therefore, when the nut 16 moves axially, it can push the sliding member 13 to move axially.

[0039] In one embodiment, the sliding member 13 is rotatably sleeved on the nut 16 in the circumferential direction, so that the sliding member 13 can rotate synchronously with the shaft 20 and can move axially under the drive of the nut 16 .

[0040] In one embodiment, at least one end of the screw rod 15 extends outside the shaft 20 to connect to a drive assembly of the screw rod 15 so that the drive assembly drives the screw rod 15 to rotate. The drive assembly can be a gear or a chain.

[0041] In one embodiment, the first fixing member 17 includes multiple fixing rods 171, each of which is mounted on the housing housing the shift mechanism. For example, the housing is a mid-mounted transmission housing housing the shift mechanism. Both sides of the housing are provided with mounting slots equal in number to the number of fixing rods 171, and the fixing rods 171 are mounted within these slots. Thus, by attaching the fixing rods 171 to the housing, the multiple fixing rods 171 can circumferentially secure the nut 16.

[0042] In one embodiment, a plurality of fixing rods 171 are passed through the nut 16 , thereby eliminating the space occupied by the first fixing member 17 in the circumferential direction.

[0043] In one embodiment, there are two shift slots 111, and each gear 30 corresponds to two pawls 12. The two pawls 12 are respectively disposed on either side of the sleeve 11 and are adapted to fit within the two shift slots 111. Accordingly, each pawl 12 corresponds to an elastic member 14. When the sleeve 11 rotates and the two corresponding pawls 12 are positioned above the two shift slots 111, the two pawls 12 rotate under the force of the corresponding elastic members 14, with one end entering the shift slot 111 and the other end tilting upward. The two pawls 12 engage with two grooves on the inner side of the gear 30, thereby locking the gear 30 and the shaft 20. When one end of the two corresponding pawls 12 is away from the shift slot 111, the two pawls 12 simultaneously return to their original position under the force of the sleeve 11, disengaging from the gear 30 and separating the gear 30 from the shaft 20. By providing two shift grooves 111 and two pawls 12 corresponding to each gear, the locking strength between the pawl 12 and the gear 30 can be improved, thereby improving the reliability of the shift mechanism 10.

[0044] In one embodiment, the number of shift grooves 111 is two, and the two ends of the slider 13 are respectively disposed in the two shift grooves 111. For example, the slider 13 includes a mounting portion and bosses protruding from both ends of the mounting portion. The mounting portion can be in the shape of a ring, which is sleeved on the nut 16. The two bosses are respectively disposed in the two shift grooves 111, and the two bosses are respectively mounted in the grooves of the shaft 20. This can improve the stability of the slider 13 during sliding, thereby improving the stability of the shift mechanism 10 during shifting.

[0045] In one embodiment, the shift mechanism 10 further includes a second fixing member 18, which is located outside the sleeve 11. The pawl 12 is rotatably mounted on the second fixing member 18. The second fixing member 18 can be fixed to the shaft 20, so that the pawl 12 rotates synchronously with the shaft 20 and rotates about the second fixing member 18 to achieve gear shifting.

[0046] In one embodiment, a limiting hole 23 is provided on the shaft 20, and the position of the limiting hole 23 is consistent with the position of the gear 30 on the shaft. The pawl 12 and the elastic member 14 are both provided in the limiting hole 23, so that the movement of the pawl 12 and the elastic member 14 can be limited in the axial direction to achieve locking of the gear 30.

[0047] In one embodiment, a mounting hole for mounting the second fixing member 18 is provided on the shaft 20 , and the second fixing member 18 is passed through the mounting hole, thereby fixing the second fixing member 18 in the axial direction, and further fixing the pawl 12 in the limiting hole.

[0048] In one embodiment, the shift mechanism 10 further includes a planetary gear assembly for rotating the sleeve 11. The sleeve 11 can be mounted at the output end of the planetary gear assembly, thereby causing the planetary gear assembly to rotate the sleeve 11. Alternatively, a screw 15 can be mounted at the output end of the planetary gear assembly, thereby causing the planetary gear assembly to rotate the screw 15, thereby driving the sleeve 11 to rotate.

[0049] The present invention also provides a mid-mounted transmission. Figure 5 As shown, the mid-mounted transmission includes a first shaft 21, a plurality of first gears 31 rotatably mounted on the first shaft 21, a second shaft 22 parallel to the first shaft 21, a plurality of second gears 32 mounted on the second shaft 22, and the aforementioned shift mechanism 10. Each first gear 31 meshes with a corresponding second gear 32. The shift mechanism 10 is mounted within the first shaft 21 to control the locking and release of the first shaft 21 from any one or more first gears 31. The first gear 31 locked with the first shaft 21 is driven to rotate by the first shaft 21, thereby driving the second shaft 22 to rotate via the second gear 32 meshing with the first gear 31. For example, a bicycle frisbee is mounted on the second shaft 22, and the rotation of the second shaft 22 provides the bicycle with forward power.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gear shift mechanism for controlling the locking and disengagement of a shaft and one or more gears mounted on the shaft; characterized in that: The shift mechanism includes: a sleeve, a pawl and an elastic member; the sleeve is located in the shaft, the pawl and the elastic member are installed in the shaft and located on the outside of the sleeve; a shift groove is provided on the sleeve, and the sleeve is used to rotate under the drive of an external force; the elastic member is used to press one end of the pawl into the shift groove when the sleeve rotates until one end of the pawl is located above the shift groove, so that the other end of the pawl is tilted to lock the shaft and the gear, and the sleeve is used to be tangent to the pawl when one end of the pawl is away from the shift groove to lift one end of the pawl, so that the other end of the pawl is reset to separate the gear and the shaft.

2. The shift mechanism according to claim 1, wherein: The shift groove is an oblique groove whose center line is not parallel to or perpendicular to the center axis of the sleeve.

3. The shift mechanism according to claim 2, characterized in that: The shift mechanism also includes a sliding member, which is inserted into the inclined groove and axially slidably installed in the shaft, and is used to make the sliding member and the sleeve rotate synchronously with the shaft when no gear shifting is required, and to drive the sleeve and the shaft to rotate relative to each other through axial movement when gear shifting is required.

4. The shift mechanism according to claim 3, characterized in that: The shift mechanism also includes a screw, a nut and a first fixing member arranged in the sleeve, the nut is mounted on the screw, the first fixing member is used to limit the nut in the circumferential direction, and the screw is used to drive the nut to move axially by rotating, so as to drive the sliding member to move axially.

5. The shift mechanism according to claim 4, characterized in that: At least one end of the screw extends outside the shaft to connect with a driving assembly of the screw.

6. The shift mechanism according to claim 4, characterized in that: The first fixing member includes a plurality of fixing rods, and both ends of the fixing rods are mounted on the housing where the shift mechanism is located.

7. The shift mechanism according to claim 6, characterized in that: A plurality of fixing rods are passed through the nuts.

8. The shift mechanism according to claim 1, wherein: The number of the shift slots is 2.

9. The shift mechanism according to claim 1 or 2, characterized in that: The shift mechanism further includes a planetary gear assembly for driving the sleeve to rotate.

10. A mid-mounted transmission, characterized in that: The shift mechanism comprises a first shaft, a plurality of first gears rotatably mounted on the first shaft, a second shaft parallel to the first shaft, a plurality of second gears mounted on the second shaft, and a shift mechanism according to any one of claims 1 to 9, wherein each first gear is engaged with a corresponding second gear; the shift mechanism is configured to be mounted in the first shaft to control the locking and release of the first shaft and any one or more of the first gears; The first gear locked with the first shaft is used to rotate under the drive of the first shaft, so as to drive the second shaft to rotate through the second gear meshing with the first gear.

Images