Axis gear shifting transmission

Abstract

The utility model belongs to the field of mechanical transmissions, and particularly discloses an axis gear shifting transmission which comprises a hollow shaft and a plurality of gear-position gears arranged on the hollow shaft in a running fit mode. An axial gear shifting groove penetrating through the side wall of the hollow shaft in the radial direction is formed in the area, where the gear is located, of the hollow shaft. The shaft center gear shifting mechanism comprises a gear shifting block which is arranged in the hollow shaft and extends out of the axial gear shifting groove in the radial direction, and a gear shifting block control mechanism which is rotationally connected to the gear shifting block and can control the gear shifting block to reciprocate in the axial direction so as to achieve the gear shifting action; the inner circle of each gear gear is provided with an axial through radial key groove and a key block forming the radial key groove, the gear shifting control mechanism drives the gear shifting block to axially move in a reciprocating mode to be meshed with the radial key groove of the corresponding gear gear to form transmission of the corresponding gear, and the purpose of upshifting or downshifting speed changing is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a gear shifting mechanism, especially a shaft center gear shifting transmission. BACKGROUND

[0002] The main responsibility of the transmission is to coordinate the engine speed and the final output speed required by the machine, to ensure the efficient performance of the engine and to obtain the best output speed and torque of the system.

[0003] The gear shifting mechanism of the conventional transmission generally uses the movement of the shift fork and the shift fork shaft to change the speed ratio of the driving wheel and the driven wheel to realize gear shifting, but this way has complex structure, many parts, large volume and weight, and often needs to disconnect the power source for gear shifting, causing temporary interruption of power. The shaft center gear shifting mechanism realized by the elastic ball has complex structure, is easy to be stuck during gear shifting and difficult to withstand large torque output, and has low reliability. Other types of overrunning gear shifting transmission have complex structure and are difficult to arrange because the overrunning shifting block is split and needs to reciprocate in a small space, are difficult to withstand large torque, and need to go through three steps of preliminary engagement, overrunning and complete engagement during each gear shifting process, which is low in efficiency.

[0004] Based on the above problems, the existing shaft center gear shifting mechanism needs to be innovated and upgraded to make the structure and operation more efficient and reliable, and the overall volume smaller to save space and weight. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a shaft center gear shifting transmission, which has simple structure, efficient and reliable operation, small overall volume, saves space and weight, does not need to interrupt the power source connection during gear shifting, can withstand large torque, and is particularly suitable for application occasions with low NVH performance requirements, such as bicycles, ATVs, UTVs, two or three wheeled motorcycles, agricultural vehicles, engineering machinery and the like.

[0006] In order to achieve the above purpose, a technical scheme adopted by the utility model is as follows:

[0007] A shaft center gear shifting transmission, comprising a hollow shaft and a plurality of gear shifting gears rotatably arranged on the hollow shaft; an axial gear shifting groove radially penetrating the side wall of the hollow shaft is arranged on the hollow shaft at the region where the gear shifting gears are located;

[0008] Further comprising a shaft center gear shifting mechanism, the shaft center gear shifting mechanism comprising a gear shifting block arranged in the hollow shaft and radially extending out of the axial gear shifting groove, and a gear shifting block operating mechanism rotatably connected to the gear shifting block to control the reciprocating movement of the gear shifting block along the axial direction to realize the gear shifting action;

[0009] The gear teeth of the gear shift gears are provided with axial through radial keyways and key blocks constituting the radial keyways, the gear shift operating mechanism drives the gear shift blocks to axially reciprocate and engage with the radial keyways of the corresponding gear shift gears to form transmission of the corresponding gears, so as to realize the purpose of upshift or downshift.

[0010] Further, the axial distance between the key blocks constituting the radial keyways of each pair of adjacent gear shift gears is equal to or greater than the axial thickness of the gear shift block.

[0011] Further, the key blocks constituting the radial keyways are spirally inclined and uniformly distributed along the axial width of the gear shift gears.

[0012] Further, the three factors of the spiral direction (left or right) of the key blocks, the rotation direction (clockwise or counterclockwise) of the gear shift gears, and the sequence (from high to low or from low to high) of the gear shift gears arranged in the same axial direction of the hollow shaft need to be matched with each other to ensure that the gear shift block can slide along the inclined surface of the key block to the radial keyway to form engagement when upshifting or downshifting.

[0013] Further, the gear shift operating mechanism includes a gear shift shaft axially penetrating into one end of the hollow shaft and rotationally connected with the gear shift block, and a gear shift driving device connected with the gear shift shaft extending out of one end of the hollow shaft and controlling the reciprocating movement thereof.

[0014] Optionally, the gear shift operating mechanism includes a gear shift shaft axially penetrating into one end of the hollow shaft and fixedly connected with the gear shift block, and a gear shift driving device rotationally connected with the gear shift shaft extending out of one end of the hollow shaft and controlling the reciprocating movement thereof.

[0015] Further, the gear shift blocks are uniformly distributed along the center circle and integrally formed with the center disc.

[0016] Further, the plurality of gear shift gears are sequentially arranged in close proximity with small gaps.

[0017] Further, the width of the radial keyway is greater than the width of the gear shift block.

[0018] Further, the gear shift block, the axial gear shift groove and the radial keyway correspond in phase.

[0019] Compared with the prior art, the shaft center gear shift transmission has a whole-shaped shift block meshing with the radial key groove on the gear shift gear, overcomes the problems of the split shift block or the ball type shift mechanism structure of the existing shaft center gear shift mechanism structure being complex and unable to bear large torque, simplifies the structure while being able to bear large torque, the key block constituting the radial key groove on the gear shift gear is provided with an inclination angle in the axial direction to form inclined surfaces on both sides, when shifting, the shift block just coming out of the radial key groove of the gear shift gear adjacent to the target gear shift gear can relatively rotate along the inclined surface of a key block of the target gear shift gear in the circumferential direction to guide the key block to preliminarily mesh with the protruding force surface of the next key block, and under the driving of the shift control mechanism, the shift block continues to move until completely meshing with the radial key groove, so that more accurate and smooth shifting action is realized. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic view of the utility model.

[0021] Figure 2 is a three-dimensional schematic view of the shift block of the utility model.

[0022] Figure 3 is a schematic view of the gear shift gear of the utility model.

[0023] Figure 4 is a cross-sectional schematic view of the gear shift gear of the utility model.

[0024] Figure 5 is an exploded schematic view of the parts of the utility model. DETAILED DESCRIPTION

[0025] The embodiments of the utility model will be specifically described below in combination with the drawings, the drawings are only for reference and description, and do not constitute the limitation on the patent protection range of the utility model.

[0026] As shown in the figure: the axial shift transmission of the embodiment includes a hollow shaft 1 and a plurality of gear wheels arranged on the hollow shaft in rotation; the hollow shaft 1 is provided with an axial shift groove 101 radially penetrating the side wall of the hollow shaft in the region where the gear wheels are located; the axial shift transmission further includes a shift mechanism arranged in the hollow shaft and extending radially out of the axial shift groove shaft, a shift block 5, and a shift control mechanism rotatably connected to the shift block and capable of controlling the axial reciprocating movement of the shift block to realize the shift action; the shift control mechanism includes a shift shaft 6 rotatably connected to the shift block at one end of the hollow shaft and penetrating the hollow shaft in the axial direction, and a shift driving device connected to the shift shaft 6 and extending out of one end of the hollow shaft to control the axial reciprocating movement of the shift shaft 6 to realize the shift action; the shift shaft 6 also can be fixedly connected to the shift block at one end of the hollow shaft penetrating the hollow shaft in the axial direction, and rotatably connected to the shift driving device at the other end extending out of the hollow shaft; the shift block moves axially along the hollow shaft and the axial shift groove under the driving of the shift control mechanism.

[0027] The shift driving device can be a rack and pinion mechanism or an electric cylinder mechanism or a manual push-pull shift shaft, all of which can achieve the purpose of pushing the shift shaft and the shift block to move axially reciprocatingly. Since it is not the focus of the present application, it will not be repeated here.

[0028] The inner circle of the gear wheel is provided with an axial through radial key groove 402 and a key block 401 constituting the radial key groove, and the shift block moves to the radial key groove of the corresponding gear wheel under the axial driving of the hollow shaft and the shift control mechanism to form the transmission of the corresponding gear position. The gear wheel refers to all the gear wheels that drive the shift block to mesh with the radial key groove when the shift shaft slides axially.

[0029] The key block constituting the radial key groove is spirally inclined and uniformly distributed along the same width of the inner circle of the gear wheel (for example, Figure 3 Figure 4 The axial ends of the key block arranged in this way are inclined surfaces, and the inclined surfaces have a guiding function for the shift block. The spiral direction of the key block needs to be matched with the rotation direction of the gear wheel and the direction of the gear wheel arranged from left to right or right to left, and whether the direction is arranged from high to low or from low to high. The purpose is to make the shift block slide into the radial key groove along the inclined surface of the key block to form meshing when the gear wheel and the hollow shaft rotate at different speeds, regardless of whether it is upshift or downshift, to ensure accurate and smooth shifting. If there is no inclined surface with a guiding function for the shift block, the shift block cannot be accurately inserted into the radial key groove to form meshing during shifting due to the speed difference between the gears, which may cause a sudden impact or even be stuck.

[0030] As shown in the figure, the three-gear transmission of the embodiment takes the driven gear as the gear wheel as an example for illustration, Figure 1As shown, the first gear 2, the second gear 3 and the third gear 4 are arranged in sequence from left to right, and the rotation direction of the gear is counterclockwise to match the right helical structure of the key block (see Figure 4 When the shift shaft drives the shift block to engage the second gear 3, the first gear 2 and the shift block are engaged and drive the hollow shaft to rotate. The specific process is as follows: the shift block is driven by the shift shaft to move left and gradually disengage from the engagement with the second gear 3, reaches between the key blocks of the second gear and the first gear (i.e. the neutral position without power transmission), continues to move left, and due to inertia, the shift block which has just disengaged from the second gear engages the key block of the first gear along the inclined surface of the key block of the first gear at a faster speed and slides into the radial key groove to form a preliminary engagement, and continues to move left until complete engagement to complete a downshift operation; the shift block is driven by the shift shaft to move right and gradually disengage from the engagement with the first gear 2, reaches between the key blocks of the first gear and the second gear (i.e. the neutral position without power transmission), continues to move right, and at this time, due to the higher speed of the second gear than the speed of the hollow shaft and the shift block, the shift block reversely slides along the inclined surface of the key block of the second gear into the radial key groove to form a preliminary engagement, and continues to move right until complete engagement to complete an upshift operation.

[0031] In this embodiment, the key block is right helical, the gear rotates counterclockwise, and the gear is arranged in sequence from low gear to high gear in the axial direction of the hollow shaft from left to right. It can also be combined as follows: the key block is left helical, the gear rotates counterclockwise, and the gear is arranged in sequence from high gear to low gear in the axial direction of the hollow shaft from left to right. Since there are many similar combinations, the correct combination method is: change two factors of the helical direction of the key block (left or right), the rotation direction of the gear (clockwise or counterclockwise) and the arrangement sequence of the gear in the same direction of the hollow shaft (from high to low or from low to high) at the same time based on any of the above combinations. If only one factor is changed or all three factors are changed at the same time, the shift block will slide out of the radial key groove along the inclined surface of the key block. In other words, at this time, the speed difference between the high and low speed gears makes the inclined surface of the key block return to the direction of the shift block and cannot smoothly enter the radial key groove. Therefore, only the correct and feasible combination needs to be selected in actual application. According to the foregoing method, the driven gear in this embodiment can also be changed to a driving gear as a gear to achieve the same function.

[0032] In this embodiment, the number of key blocks on the gear is 4, and the corresponding 4 radial key grooves are formed (seeFigure 3 ), the number of shift blocks is also 4, which are evenly distributed along the center disc and integrally formed with the center disc (see Figure 2 ), the number of axial shift grooves is 4; the shift block, the axial shift groove and the radial key groove correspond in phase, and the phase correspondence refers to the distribution in the circumferential direction can enable the shift block to engage into the radial key groove; generally, 4 can achieve better use effect, and in actual application, the number of shift blocks, axial shift grooves and radial key grooves can be flexibly set according to the foregoing principles.

[0033] In this embodiment, the shift can only be sequentially changed from high to low or from low to high one gear at a time, and cannot be skipped, so that the problem of engine being stalled and vehicle stalling due to misoperation will not occur, and the speed difference between the gears during gear addition and subtraction is the smallest, which can ensure smooth gear shifting and will not cause jerky impact.

[0034] In this embodiment, the plurality of gear gears are sequentially and closely arranged with small gaps, that is, they are sequentially and juxtaposed from high to low or from low to high, as shown in the figure, the first gear gear 2, the second gear gear 3 and the third gear gear 4 are sequentially arranged from left to right without any gap therebetween, and only a gap needs to be reserved to avoid rotation interference.

[0035] In this embodiment, the distance between the key blocks of two adjacent gear gears is greater than the axial thickness of the shift block, so as to ensure that there is no interference and jamming between the gears during shifting.

[0036] In this embodiment, the width of the radial key groove is slightly greater than the width of the shift block, at least being a sliding fit, so as to ensure that the shift block can smoothly disengage and enter the radial key groove to realize engagement.

[0037] In this embodiment, the power source does not need to be cut off during shifting, and the adjacent low-speed gear can be directly engaged from the high-speed gear or the adjacent high-speed gear can be directly engaged from the low-speed gear, so that the shifting is accurate and efficient.

[0038] In this embodiment, when the shift block slides along the slope of the key block of the gear gear to the radial key groove to form preliminary engagement, the sliding of the shift block on the slope of the key block has a friction synchronization effect, so that the engagement with the radial key groove is smoother.

[0039] In this embodiment, the shift block is integrally formed and engaged with the radial key groove formed by the key block integrally formed on the gear gear, so it can withstand large torque.

[0040] In this embodiment, no synchronization ring, shift fork, synchronization clutch and other parts in the traditional transmission are needed, which greatly simplifies the overall structure, achieves the effect of reducing weight and reducing volume.

[0041] The above disclosed is only the preferred embodiment of the utility model, and cannot be used to limit the protection scope of the utility model, so equivalent changes made in the patent application range of the utility model still belong to the range covered by the utility model.

Claims

1. A shaft-centric gear transmission, characterized by: The hollow shaft and a plurality of gear wheels are arranged in the hollow shaft by rotating fit; the hollow shaft is provided with an axial shifting slot penetrating the side wall of the hollow shaft in the region where the gear wheels are arranged; The shaft center shifting mechanism comprises a shifting block arranged in the hollow shaft and extending radially out of the axial shifting slot, and a shifting control mechanism rotatingly connected to the shifting block and capable of controlling the axial reciprocating movement of the shifting block to realize shifting action; The inner circle of the gear wheel is provided with an axial through radial key groove and a key block forming the radial key groove and being spirally inclined, the shifting control mechanism drives the axial reciprocating movement of the shifting block and the radial key groove of the corresponding gear wheel to mesh to form transmission of the corresponding gear position, realizing the purpose of upshifting or downshifting.

2. The axial shift transmission of claim 1, wherein: The axial distance between the key blocks forming the radial key grooves of each pair of adjacent gear wheels is greater than the axial thickness of the shifting block.

3. The axial path change transmission of claim 1, wherein: The key blocks forming the radial key grooves are spirally inclined and uniformly distributed along the same axial width of the inner circle of the gear wheel.

4. The axial path change transmission of claim 1, wherein: The three factors of the spiral direction of the key blocks, i.e. left or right, the rotating direction of the gear wheel, i.e. clockwise or counterclockwise, and the sequence of the gear wheels arranged in the same axial direction of the hollow shaft, i.e. from high to low or from low to high, need to be matched to ensure that the shifting block can slide along the inclined surface of the key block to the radial key groove to form meshing due to the speed difference between the gear positions when upshifting or downshifting.

5. The axial path change transmission of claim 1, wherein: The shifting control mechanism comprises a shifting shaft penetrating into the hollow shaft at one end and rotatingly connected to the shifting block, and a shifting driving device connected to the shifting shaft extending out of the hollow shaft at one end and controlling the reciprocating movement thereof.

6. The axial shift transmission of claim 5, wherein Optionally, the shifting control mechanism comprises a shifting shaft penetrating into the hollow shaft at one end and fixedly connected to the shifting block, and a shifting driving device rotatingly connected to the shifting shaft extending out of the hollow shaft at one end and controlling the reciprocating movement thereof.

7. The axial path change transmission of claim 1, wherein: The shifting blocks are uniformly distributed along the center disc and integrally formed with the center disc.

8. The axial path change transmission of claim 1, wherein: The plurality of gear wheels are arranged in sequence with small gaps.

9. The axial path change transmission of claim 1, wherein: The width of the radial key groove is greater than the width of the shifting block.

10. The axial path change transmission of claim 1, wherein: The shifting block, the axial shifting slot and the radial key groove correspond in phase.

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