Axis gear shifting transmission

Abstract

The invention 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 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 upshift or downshift speed changing is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to a shift mechanism, in particular to a shaft center shift 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 shift 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 the shift, but this way has complex structure, many parts, large volume and weight, and often needs to disconnect the power source for shifting, causing temporary interruption of power. The shaft center shift mechanism realized by the elastic ball has complex structure, and the shift is easy to be stuck and difficult to withstand large torque output, and the reliability is not high. Other types of overrunning shift transmission have complex structure and are difficult to arrange because the overrunning shift block is split and needs to reciprocate in a small space. It is difficult to withstand large torque, and each shift process needs to go through three steps of preliminary engagement, overrunning and complete engagement, which is low in efficiency.

[0004] Based on the above problems, it is necessary to innovate and upgrade the existing shaft center shift mechanism, so that the structure and operation are more efficient and reliable, and the overall volume is small, saving space and weight. SUMMARY

[0005] The present application aims to provide a shaft center shift transmission with simple structure, efficient and reliable operation, small overall volume, saving space and weight, without interrupting the power source connection during shifting, capable of withstanding large torque, and particularly suitable for application occasions with low NVH performance requirements such as bicycles, ATVs, UTVs, two and three wheeled motorcycles, agricultural vehicles, engineering machinery, etc.

[0006] In order to achieve the above purpose, a technical scheme adopted by the present application is as follows: A shaft center shift transmission, comprising a hollow shaft and a plurality of gear wheels rotatably arranged on the hollow shaft; an axial shift slot radially penetrating the side wall of the hollow shaft is arranged on the hollow shaft in the region of the gear wheels; Further comprising a shaft center shift mechanism, the shaft center shift mechanism comprising a shift block arranged in the hollow shaft and radially extending out of the axial shift slot, and a shift block operating mechanism rotatably connected to the shift block to control the axial reciprocating movement of the shift block to realize the shift action; The inner circle of the gear is provided with axial through radial keyway and key block constituting radial keyway, the gear shift operating mechanism drives the shift block to axially reciprocate and engage with the radial keyway of the corresponding gear to form the transmission of the corresponding gear, so as to realize the purpose of upshift or downshift.

[0007] Further, the axial distance between the key blocks constituting the radial keyway of each pair of adjacent gears is equal to or greater than the axial thickness of the shift block.

[0008] Further, the key blocks constituting the radial keyway are spirally inclined and uniformly distributed along the same axial width of the gear inner circle.

[0009] Further, the three factors of the spiral direction (left or right) of the key block, the rotation direction (clockwise or counterclockwise) of the gear, and the sequence (from high to low or from low to high) of the gears arranged in the same axial direction of the hollow shaft need to be matched to ensure that the shift block can slide along the inclined surface of the key block to the radial keyway to form engagement when upshifting or downshifting.

[0010] Further, the gear shift operating mechanism includes a shift shaft axially penetrating into one end of the hollow shaft and rotationally connected with the shift block, and a shift driving device connected with the shift shaft extending out of one end of the hollow shaft and controlling the reciprocating movement thereof.

[0011] Optionally, the gear shift operating mechanism includes a shift shaft axially penetrating into one end of the hollow shaft and fixedly connected with the shift block, and a shift driving device rotationally connected with the shift shaft extending out of one end of the hollow shaft and controlling the reciprocating movement thereof.

[0012] Further, the shift blocks are uniformly distributed along the center circle and integrally formed with the center disc.

[0013] Further, the plurality of gear teeth are arranged in sequence with small gaps.

[0014] Further, the width of the radial keyway is greater than the width of the shift block.

[0015] Further, the shift block, the axial shift groove and the radial keyway correspond in phase.

[0016] ​Compared with the prior art, the shaft center gear shifting device of the present application has a whole-shaped shifting block engaging with the radial key groove on the gear wheel, which overcomes the problem of complex structure and inability to bear large torque of the split shifting block or ball shifting mechanism of the prior art shaft center gear shifting mechanism, simplifies the structure while being able to bear large torque, the key block constituting the radial key groove on the gear wheel is provided with an inclined angle in the axial direction to form inclined surfaces on both sides, which enables the shifting block just coming out of the radial key groove of the gear wheel adjacent to the target gear wheel to relatively rotate along the inclined surface of a key block of the target gear wheel in the circumferential direction to preliminarily engage with the protruding force surface of the next key block, and continuously moves under the driving of the gear shifting operating mechanism until completely engaging with the radial key groove, so as to realize more accurate and smooth gear shifting action. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of the present application.

[0018] Figure 2 is a three-dimensional schematic diagram of the shifting block of the present application.

[0019] Figure 3 is a schematic diagram of the gear wheel of the present application.

[0020] Figure 4 is a sectional schematic diagram of the gear wheel of the present application.

[0021] Figure 5 is an exploded schematic diagram of the parts of the present application. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail below with reference to the accompanying drawings, which are only used for reference and illustration, and do not constitute a limitation on the scope of patent protection of the present application.

[0023] As shown in the drawings: the axial gear shifting device of the present embodiment includes a hollow shaft 1 and a plurality of gear wheels rotatably arranged on the hollow shaft; the hollow shaft 1 is provided with an axial gear shifting groove 101 radially penetrating the side wall of the hollow shaft at the region where the gear wheels are located; further including a shaft center gear shifting mechanism, which includes a gear shifting block 5 arranged in the hollow shaft and radially extending out of the axial gear shifting groove shaft, and a gear shifting operating mechanism rotatably connected to the gear shifting block to control the axial reciprocating movement of the gear shifting block to realize gear shifting action; the gear shifting operating mechanism includes a gear shifting shaft 6 rotatably connected to the gear shifting block at one end of the hollow shaft in the axial direction, and a gear shifting driving device connected to the gear shifting shaft 6 extending out of one end of the hollow shaft to control the axial reciprocating movement of the gear shifting shaft to realize gear shifting action; the gear shifting shaft 6 rotatably connected to the gear shifting block at one end of the hollow shaft in the axial direction can also be fixedly connected to the gear shifting block, and the other end extending out of the hollow shaft is rotatably connected to the gear shifting driving device; the gear shifting block reciprocates along the hollow shaft and the axial gear shifting groove under the driving of the gear shifting operating mechanism.

[0024] The shift drive device can be a rack and pinion mechanism or an electric cylinder mechanism or a manual push-pull shift shaft, which can achieve the purpose of axial reciprocating motion of the shift shaft and the shift block. Since this is not the focus of the present application, it will not be repeated here.

[0025] The inner circle of the gear is provided with an axial through radial key groove 402 and a key block 401 constituting the radial key groove. The shift block moves to the corresponding radial key groove of the gear under the axial drive of the hollow shaft and the shift control mechanism to form the transmission of the corresponding gear. The gear refers to all gears that drive the shift block to engage with the radial key groove when the shift shaft slides axially.

[0026] 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. Figure 3 Figure 4 The axial ends of the key block arranged in this way are inclined surfaces, which 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 and the direction of the gear from left to right or right to left, and the order of arrangement 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 engagement, whether it is upshift or downshift, because of the speed difference between the gears and the hollow shaft, to ensure smooth and accurate shifting. If there is no inclined surface with guiding function for the shift block, because of the speed difference between the gears, the shift block cannot be accurately inserted into the radial key groove to form engagement during shifting, which may cause impact and even jam.

[0027] As shown in the figure, the three-speed transmission with the driven gear as the gear is taken as an example for illustration. Figure 1 As shown in the figure, the first gear 2, the second gear 3 and the third gear 4 are arranged from left to right, and the rotation direction of the gear is counterclockwise to match the right spiral structure of the key block (see Figure 4), to ensure that the shift block can slide along the inclined surface of the key block into the radial key groove to form engagement due to the speed difference between the gear and the hollow shaft, when the shift shaft drives the shift block to engage the first gear 2 from the second gear 3, the first gear 2 engages the shift block and drives the hollow shaft to rotate, the specific process is as follows: the shift block is driven by the shift shaft to move left to gradually disengage from the engagement with the second gear 3, reaches between the key blocks of the second and first gears (i.e. the neutral position without power transmission), continues to move left, due to inertia, the shift block which has just disengaged from the engagement with the second gear slides along the inclined surface of the key block of the first gear with a relatively slow speed towards the radial key groove to form a preliminary engagement, continues to move left until complete engagement to complete a downshift operation; the shift block is driven by the shift shaft to move right to gradually disengage from the engagement with the first gear 2, reaches between the key blocks of the first and second gears (i.e. the neutral position without power transmission), continues to move right, at this time, due to the speed of the second gear being greater 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 towards the radial key groove to form a preliminary engagement, continues to move right until complete engagement to complete a upshift operation.

[0028] In this embodiment, the key block is right-handed, the gear rotates counterclockwise, and the gears are arranged in sequence from low to high in the axial direction of the hollow shaft from left to right; it can also be combined as follows: the key block is left-handed, the gear rotates counterclockwise, and the gears are arranged in sequence from high to low 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 of the three factors of the spiral direction of the key block (left or right), the rotation direction of the gear (clockwise or counterclockwise), and the arrangement order of the gears in the same direction of the hollow shaft (from high to low or from low to high) at the same time; if only one of the three factors 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 to engage; therefore, in actual application, only the correct and feasible combination needs to be selected; 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.

[0029] In this embodiment, the number of key blocks on the gear is 4, which are evenly distributed along the inner circle and correspondingly form 4 radial key grooves (see Figure 3 ), and the number of shift blocks is also 4, which are evenly distributed along the center disc and formed as a whole 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, the phase correspondence refers to the distribution in the circumferential direction can make the shift block can engage into the radial key groove; usually 4 can achieve better use effect, in actual application, the number of shift block, axial shift groove and radial key groove can be flexibly set according to the foregoing principle.

[0030] In the 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 is avoided, and the speed difference between gears is minimized, which can ensure smooth gear shifting and avoid jerky impact.

[0031] In the 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, only a gap is reserved to avoid rotation interference.

[0032] In the 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 gears during shifting.

[0033] In the embodiment, the width of the radial key groove is slightly greater than the width of the shift block, at least is sliding fit, so as to ensure that the shift block can smoothly disengage and enter the radial key groove to realize engagement.

[0034] In the 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.

[0035] In the embodiment, during the process that 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 shift block slides on the slope of the key block with friction synchronization effect, so that the engagement with the radial key groove is more smooth.

[0036] In the 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.

[0037] In the embodiment, no synchronous ring, fork, synchronous clutch and other parts in the traditional transmission are needed, which greatly simplifies the overall structure, achieves the effect of reducing weight and size.

[0038] The above disclosure is only the preferred embodiment of the present application, which cannot limit the protection scope of the present application, so the equivalent changes made in the patent application scope of the present application still belong to the scope covered by the present application.

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 gear shifting slot penetrating the side wall of the hollow shaft in the region where the gear wheels are arranged; The shaft core gear shifting mechanism comprises a gear shifting block arranged in the hollow shaft and extending radially out of the axial gear shifting slot, and a gear shifting control mechanism rotating connected to the gear shifting block and capable of controlling the axial reciprocating movement of the gear shifting block to realize gear 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, which is spirally inclined; the gear shifting control mechanism drives the axial reciprocating movement of the gear shifting block and engages with the radial key groove of the corresponding gear wheel to form the transmission of the corresponding gear position, realizing the purpose of gear upshift or downshift.

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 gear 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 (left or right) of the key block, the rotating direction (clockwise or counterclockwise) of the gear wheel, and the sequence (from high to low or from low to high) of the gear wheels arranged in the same axial direction of the hollow shaft need to be matched with each other to ensure that the gear shifting block can slide along the inclined surface of the key block to the radial key groove to form engagement when upshifting or downshifting.

5. The axial path change transmission of claim 1, wherein: The gear shifting control mechanism comprises a gear shifting shaft penetrating into the hollow shaft at one end and rotating connected with the gear shifting block, and a gear shifting driving device connected with the gear 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 gear shifting control mechanism comprises a gear shifting shaft penetrating into the hollow shaft at one end and fixedly connected with the gear shifting block, and a gear shifting driving device rotating connected with the gear 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 gear shifting block is 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 gear shifting block.

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

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