CVT gearbox

Abstract

The utility model relates to the technical field of gearboxes, in particular to a CVT gearbox which comprises a gearbox, a driving shaft, a driven shaft and an output shaft, the driving shaft, the driven shaft and the output shaft are arranged on the gearbox, an input wheel and a driving wheel are sequentially arranged on the driving shaft, a driven wheel is arranged on the driven shaft, and the driven wheel and the driving wheel are in transmission through a belt. The lower end of the driven shaft is in transmission with the output shaft through a gear set in the gearbox, the gearbox further comprises a first retainer and two first bearings, and the first retainer is fixed to the gearbox; the two first bearings are both installed on the driven shaft, one end of the driven shaft is rotationally connected with the gearbox through one first bearing, and the other end of the driven shaft is rotationally connected with the first retainer through the other first bearing. The driven wheel is located between the two first bearings. The installation positions of the driving wheel and the input wheel on the driving shaft can be lowered, the gravity center of the whole mower is lowered finally, and the stability of the mower in the advancing process is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of gearboxes, in particular to a CVT gearbox. Background Art

[0002] For riding lawn mowers, a gearbox is generally provided to achieve speed change and reversing.

[0003] In related technologies, such as Fig.11 As shown, some riding lawn mowers use a CVT gearbox, which is mainly composed of a gearbox, a gear set arranged in the gearbox, a driving shaft 2, a driven shaft 3, an output shaft 4, etc. A driving wheel 22 is arranged on the driving shaft 2, and a driven wheel 31 is arranged on the driven shaft 3. The driving wheel 22 and the driven wheel 31 are driven by a belt; the output shaft 4 is driven by the driven shaft through the gear set in the gearbox; an input wheel 21 is also arranged on the driving shaft, and the input wheel 21 is mainly used to connect with the power source (such as an engine) of the lawn mower. When working, the power source drives the driving shaft 2 to rotate, and the driven shaft 3 is driven to rotate under the transmission of the belt. The driven shaft then drives the output shaft 4 to rotate through the gear set, so as to complete the entire transmission process.

[0004] For this kind of CVT transmission in practical applications, such as Fig.11 As shown, the driven shaft is generally rotatably mounted on the gear box corresponding to the gear set position through two bearings 32; the driven wheel is located on the upper side of the two bearings 32. The disadvantage of this installation method is that since the two bearings 32 are located below the driven wheel, more space at the lower part of the driven shaft will be occupied, so that the installation position of the driven wheel on the driven shaft will be higher. The installation position here can also be understood as the distance A between the center axis of the driven shaft and the output shaft (such as Fig.11 As shown), that is, the spacing A will be enlarged, and the spacing A will generally be above 80 mm; and the center of the driving wheel is generally at the same height as the center of the driven wheel. In this way, when the driven wheel is at a higher position, the driving wheel position will also be higher accordingly, and the input wheel is located above the driving wheel, so the input wheel position on the driving shaft will also be higher, and the installation position of the power source connected to the input wheel on the lawn mower will also be raised, thereby causing the center of gravity of the entire lawn mower to be higher, affecting the travel stability of the lawn mower, and thus there is room for improvement. Utility Model Content

[0005] In order to solve at least one technical problem mentioned in the background technology, the purpose of the present utility model is to provide a CVT gearbox.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A CVT gearbox comprises a gearbox, and a driving shaft, a driven shaft and an output shaft arranged on the gearbox, wherein the driving shaft is provided with an input wheel and a driving wheel in sequence, and the driven shaft is provided with a driven wheel, and a belt transmission is used between the driven wheel and the driving wheel; the lower end of the driven shaft is transmitted to the output shaft through a gear set in the gearbox, and the gearbox further comprises a first retaining frame and two first bearings, wherein the first retaining frame is fixed to the gearbox; the two first bearings are both mounted on the driven shaft, one end of the driven shaft is rotatably connected to the gearbox through one of the first bearings, and the other end is rotatably connected to the first retaining frame through another first bearing; the driven wheel is located between the two first bearings.

[0008] Compared with the prior art, the advantages of adopting this solution are:

[0009] In the present solution, a first retaining frame is arranged at the position of the driven shaft, so that the first retaining frame can be used as the installation position of one of the first bearings, so that the two first bearings can be respectively distributed on the upper and lower sides of the driven wheel on the driven shaft, which is equivalent to having only one first bearing on the lower side of the driven wheel, thereby reducing the occupation of the lower space of the driven shaft. Compared with the method in which both bearings are located on the lower side of the driven wheel in the related art, the installation position of the driven wheel on the driven shaft can be lowered, and accordingly, the installation position of the driving wheel and the input wheel on the driving shaft can be lowered, thereby making it possible to reduce the installation position of the power source connected to the input wheel on the lawn mower, thereby lowering the center of gravity of the entire lawn mower to improve the stability of the lawn mower when traveling.

[0010] As an optional implementation of the present invention, the first retaining frame includes at least one first support leg, and the first support leg is at least partially blocked on the outside of the belt and is gap-matched with the belt.

[0011] As an optional embodiment of the utility model, the first retaining frame includes three of the first legs, the belt forms a first tangent point and a second tangent point at the tangent points with the driven wheel at the positions where the belt enters and exits the driven wheel, and the belt and the driven wheel form a third tangent point at the tangent point between the first tangent point and the second tangent point, and the third tangent point is located on the perpendicular bisector of the line connecting the first tangent point and the second tangent point; three of the first legs, two of which are located at the first tangent point and the second tangent point, respectively, and the other is located at the third tangent point.

[0012] As an optional implementation manner of the present utility model, the first retaining frame further includes a mounting portion disposed on the top of the first supporting leg, and the first bearing is mounted on the mounting portion.

[0013] As an optional implementation manner of the present utility model, a center line connecting the driving wheel and the driven wheel is parallel to the output shaft.

[0014] As an optional embodiment of the present invention, the distance between the center of the driven wheel and the central axis of the output shaft is A, wherein 55mm≤A≤75mm, and / or the distance between the center of the input wheel and the central axis of the output shaft is E, wherein 100mm≤E≤115mm.

[0015] As an optional embodiment of the utility model, the output shaft includes two sections of shaft bodies, a differential gear is provided between the two sections of the shaft bodies, and a first gear meshing with the differential gear is provided at one end of the shaft body close to the differential gear; the differential gear meshes with the gear set in the reduction box for transmission.

[0016] As an optional implementation manner of the present invention, in the axial direction of the output shaft, the differential gear is located between the driving shaft and the driven shaft; and / or the driving shaft and the driven shaft are located on the same side of the output shaft.

[0017] As an optional embodiment of the utility model, the gearbox also includes a second retaining frame and two second bearings, the second retaining frame is fixed to the gear box; the upper part of the driving shaft is rotatably connected to the retaining frame through one of the second bearings, and the lower part of the driving shaft is rotatably connected to the gear box through another second bearing; the driving wheel is located between the two second bearings; and the input wheel is located at the top of the driving shaft.

[0018] As an optional embodiment of the utility model, the driving wheel and the driven wheel are both movable pulleys, and the movable pulleys include two wheel discs that can move relative to each other in the axial direction and keep relative positioning in the circumferential direction, and the two wheel discs are arranged axially to form a wheel groove for the belt to be embedded, and the wheel groove gradually widens radially outward; wherein,

[0019] The driven shaft is provided with a first elastic member, and the first elastic member is used to provide a first elastic force to drive the two wheel discs of the driven wheel to move closer to each other;

[0020] The driving shaft is provided with a second elastic member, and the second elastic member is used to provide a second elastic force to drive the two wheel discs of the driving wheel away from each other;

[0021] The gearbox also includes a clutch mechanism, which is used to drive the two wheel discs of the driving wheel to approach each other.

[0022] Other advantages and effects of the present invention are explained in detail in the specific implementation manner and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the utility model;

[0024] Figure 2 This is a schematic diagram of the structure of the utility model when the input wheel is separated;

[0025] Figure 3 It is a top view of the utility model;

[0026] Figure 4 for Figure 3 Cross-section from the middle MM perspective;

[0027] Figure 5 for Figure 4 A partial enlarged view of the driven shaft position;

[0028] Figure 6 It is a structural schematic diagram of the first retainer of the utility model;

[0029] Figure 7 It is a partial exploded view of the utility model;

[0030] Figure 8 It is a top view of the differential gear position of the utility model;

[0031] Fig. 9 It is a structural schematic diagram of the differential gear and the output shaft of the utility model;

[0032] Fig.10 This is a front view of the differential gear position of the utility model;

[0033] Fig.11 It is a structural diagram of the related technology. DETAILED DESCRIPTION

[0034] The following is an explanation and description of the technical scheme of the embodiment of the utility model in conjunction with the drawings of the embodiment of the utility model, but the following embodiment is only a preferred embodiment of the utility model, not all. Based on the embodiment in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the utility model.

[0035] In the following description, terms such as "inside", "outside", "up", "down", "left", "right", etc. that indicate directions or positional relationships are only used to facilitate the description of the embodiments and simplify the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operate in a specific direction. Therefore, it should not be understood as a limitation on the present invention.

[0036] See also Figure 1-10 As shown, this embodiment provides a CVT gearbox, which is mainly used in a riding lawn mower to achieve speed change and direction reversal when the lawn mower is moving. The riding lawn mower can be a European riding lawn mower.

[0037] The CVT transmission provided in this embodiment mainly includes a gearbox 1, and a driving shaft 2, a driven shaft 3 and an output shaft 4 arranged on the gearbox 1; a gear set for speed change is arranged in the gearbox 1.

[0038] like Figure 1 and Figure 4 As shown, the driving shaft 2 and the driven shaft 3 are both perpendicular to the output shaft 4. An input wheel 21 and a driving wheel 22 are sequentially provided on the driving shaft 2. The input wheel 21 is located on the upper side of the driving wheel 22 and is mainly used for linkage with the power source of the lawn mower (such as the engine of the lawn mower). Generally, the input wheel 21 is a pulley structure, and the power source is transmitted through a transmission belt; the driving wheel 22 and the input wheel 21 both rotate synchronously with the driving shaft 2.

[0039] The driven shaft 3 is installed on the gear box 1 at a position corresponding to the gear set in the gear box 1 , and the lower end of the driven shaft 3 is driven by the output shaft 4 through the gear set in the gear box 1 .

[0040] like Figure 5 As shown, a driven wheel 31 capable of rotating synchronously with the driven shaft 3 is provided on the driven shaft 3, wherein the center of the driven wheel 31 and the center of the driving wheel 22 are at the same height. It can also be understood that the center line of the driving wheel 22 and the driven wheel 31 is parallel to the output shaft 4, that is, the distance between the centers of the two and the central axis of the output shaft 4 is equal, as shown in FIG. Fig.10 shown.

[0041] like Figure 2 As shown, a belt 5 is sleeved between the driving wheel 22 and the driven wheel 31 , and the driven wheel 31 and the driving wheel 22 are driven by the belt 5 .

[0042] The specific transmission process is that the power source drives the driving shaft 2 to rotate through the input wheel 21, and then drives the driving wheel 22 to rotate. The driving wheel 22 drives the driven wheel 31 to rotate through the belt 5, and then the driven wheel 31 drives the driven shaft 3 to rotate. The driven shaft 3 then drives the output shaft 4 to rotate through the gear set in the gear box 1, so as to realize the power transmission to the output shaft 4.

[0043] In addition, if Figure 7 As shown, the CVT gearbox provided in this embodiment further includes a first retaining frame 8 and two first bearings 32 , and the first retaining frame 8 is fixed on the gearbox 1 .

[0044] like Figure 5 As shown, the two first bearings 32 are both mounted on the driven shaft 3 , wherein in the axial direction of the driven shaft 3 , the driven wheel 31 is located between the two first bearings 32 .

[0045] The lower part of the driven shaft 3 is rotatably connected to the gear box 1 through the first bearing 32 on the lower side of the driven wheel 31 , and the upper part of the driven shaft 3 is rotatably connected to the first retaining frame 8 through the first bearing 32 on the upper side of the driven wheel 31 .

[0046] Through the above arrangement, the two first bearings 32 can be respectively distributed on the upper and lower sides of the driven wheel 31 on the driven shaft 3, which is equivalent to having only one first bearing 32 on the lower side of the driven wheel 31. In this way, the space occupied by the lower part of the driven shaft 3 can be reduced. Fig.11 In the manner in which both bearings 32 are located at the lower side of the driven wheel 31, the installation position of the driven wheel 31 on the driven shaft 3 can be lowered, and accordingly, the installation positions of the driving wheel 22 and the input wheel 21 on the driving shaft 2 can be lowered, thereby making it possible to lower the installation position of the power source connected to the input wheel 21 on the lawn mower, thereby lowering the center of gravity of the entire lawn mower to improve the stability of the lawn mower when traveling.

[0047] It is worth noting that, in this embodiment, Figure 4 As shown, the height of the driving wheel 22 refers to the distance A between the center of the driving wheel 22 and the central axis of the output shaft 4, and the height of the driven wheel 31 refers to the distance between the center of the driven wheel 31 and the central axis of the output shaft 4, which is equal to the distance A. The height of the input wheel 21 refers to the distance E between the center of the input wheel 21 and the central axis of the output shaft 4.

[0048] Generally speaking, in the related art where both bearings are installed at the lower side of the driven wheel 31, the height of the driven wheel 31, i.e., the spacing A, is generally above 80 mm. In this embodiment, the height of the driven wheel 31, i.e., the spacing A, is generally 55 mm ≤ A ≤ 75 mm; correspondingly, the height of the input wheel 21, i.e., the spacing E, is 100 mm ≤ E ≤ 115 mm. It can be seen that the height of the driven wheel 31 is reduced.

[0049] In addition, in this embodiment, both the driving wheel 22 and the driven wheel 31 are pulley structures. In order to prevent the belt 5 from coming out of the wheel groove G of the driven wheel 31 and causing the belt to come off, in this embodiment:

[0050] like Figure 2 and Figure 6 As shown, the first retaining frame 8 includes at least one first support leg 81, which at least partially blocks the outside of the belt 5 and cooperates with the gap between the belt 5, that is, a partial area of ​​the first support leg 81 blocks the outside of the belt 5 to limit the belt 5 and prevent the belt 5 from slipping out of the wheel groove G of the driven wheel 31.

[0051] The clearance fit here means that there is a certain distance between the first support leg 81 and the outer belt surface of the belt 5 to avoid friction between the belt 5 and the first support leg under normal transmission; in addition, the distance should not be too large, and the distance must ensure that the belt 5 will not slip out of the wheel groove G of the driven wheel 31. The specific size is designed according to the thickness of the belt 5.

[0052] In this embodiment, it is preferred that Figure 6 As shown, the first retaining frame 8 includes three first supporting legs 81 , and the three first supporting legs 81 are sequentially distributed along the circumference of the driven wheel 31 .

[0053] In this embodiment, Figure 3 As shown, the points where the belt 5 is tangent to the driven wheel 31 at the entry and exit positions of the driven wheel 31 are respectively recorded as the first tangent point B and the second tangent point C. The entry and exit positions of the driven wheel 31 here can be understood as the belt 5 winding in from one side of the driven wheel 31, that is, entering the driven wheel 31 position, and the belt 5 winding out from the other side of the driven wheel 31, that is, exiting the driven wheel 31 position.

[0054] There is also a third tangent point between the belt 5 and the driven wheel 31, and the position of the tangent point is recorded as the third tangent point D. The third tangent point D is located between the first tangent point B and the second tangent point C, and is on the perpendicular bisector of the line connecting the first tangent point B and the second tangent point C. At this time, the third tangent point D is equivalent to the far point or vertex position of the driven wheel 31.

[0055] Among them, Figure 3 As shown, the three first legs 81 are specifically distributed as follows: the first first leg 81 is located at the first tangent point B, and the belt 5 is blocked at the first tangent point B; the second first leg 81 is located at the second tangent point C, and the belt 5 is blocked at the second tangent point C; the third first leg 81 is located at the third tangent point D, and the belt 5 is blocked at the third tangent point D; through the distribution of the above three first legs 81, the belt 5 that is simultaneously wound around the driven wheel 31 can be blocked at the position where the belt 5 enters and exits the driven wheel 31 and at the vertex position of the driven wheel 31, thereby greatly reducing the risk of the belt 5 escaping from the driven wheel 31.

[0056] In this embodiment, Figure 6As shown, the specific structure of the first retainer 8 is that the first retainer 8 also includes a mounting portion 82 arranged on the top of the first support leg, the first bearing 32 is mounted on the mounting portion 82, and the mounting portion 82 is a hollow cylindrical structure to adapt to the installation of the first bearing 32; the three first support legs 81 are basically L-shaped structures, which mainly include a first foot portion 811 and a second foot portion 812, and one end of the first foot portion 811 and the second foot portion 812 are connected to form an L-shaped structure. In addition, the three first support legs 81 are respectively distributed along the circumference of the mounting portion 82, wherein the first foot portion 811 is fixed on the gear box 1, and the second foot portion 812 is fixed on the mounting portion 82; the first foot 811 is located on the outside of the belt 5 to form a block to the belt 5, as shown in FIG. Figure 2 shown.

[0057] In this embodiment, in order to enable the output shaft 4 to be reversible, in this embodiment, Figure 3 ,as well as Figure 8-10 As shown, the output shaft 4 is rotatably installed in the gearbox 1; the output shaft 4 includes two shaft bodies 41, and in the initial state, the two shaft bodies 41 are coaxially arranged; a differential gear 7 is arranged between the two shaft bodies 41, and the differential gear 7 is arranged in the gearbox 1.

[0058] The ends of the two shafts 41 close to the differential gear 7 are both provided with a first gear 71 meshing with the differential gear 7; the differential gear 7 meshes with the gear set in the gear box 1 for transmission, and under the transmission of the first gear 71 and the differential gear 7, the output shaft 4 can be reversed.

[0059] In addition, in order to reduce the wear of the output shaft 4 in this embodiment, in this embodiment, Fig. 9 As shown, in the axial direction of the output shaft 4, the differential gear 7 is located between the driving shaft 2 and the driven shaft 3. Such an arrangement can make the lengths of the two shaft bodies 41 constituting the output shaft 4 basically similar, so that the forces on the two shaft bodies 41 can be relatively balanced during transmission, reducing the problem of severe unilateral wear due to uneven force.

[0060] In other words, if the driving shaft 2 and the driven shaft 3 are located on the same side of the differential gear 7 in the axial direction of the output shaft 4, one shaft 41 will be longer and the other shaft 41 will be shorter. In this way, the two shafts 41 will be subjected to uneven force during actual operation, resulting in severe unilateral wear.

[0061] In addition, in this embodiment, it is preferred that Figure 8 and Fig. 9 As shown, the driving shaft 2 and the driven shaft 3 are located on the same side of the output shaft 4. This allows the other side of the output shaft 4 to have more space for the installation of other accessories of the lawn mower.

[0062] In this embodiment, Figure 2 As shown, the provided CVT gearbox also includes a second retaining frame 23 and two second bearings (not shown in the figure due to viewing angle), and the second retaining frame 23 is fixed on the gear box 1; in this embodiment, the main structures of the first retaining frame 8 and the second retaining frame 23 are basically the same, and the description of the first retaining frame 8 can be referred to, and no further details will be given here.

[0063] The upper part of the driving shaft 2 is rotatably connected to the retaining frame through one of the second bearings, and the lower part of the driving shaft 2 is rotatably connected to the gear box 1 through another second bearing; the driving wheel 22 is located between the two second bearings; the input wheel 21 is located at the top of the driving shaft 2 and at the top of the second retaining frame 23.

[0064] In the present embodiment, in order to achieve speed change between the driving wheel 22 and the driven wheel 31, in the present embodiment, the driving wheel 22 and the driven wheel 31 are both movable pulleys, and the movable pulleys include two wheel discs that can move relative to each other in the axial direction and maintain relative positioning in the circumferential direction. The two wheel discs are axially spaced to form a wheel groove G for the belt 5 to be embedded, and the wheel groove G gradually widens radially outward.

[0065] Based on this, for ease of understanding, in this embodiment, the two wheels of the driven wheel 31 are respectively recorded as the first wheel 311 and the second wheel 312, and correspondingly, the two wheels of the driving wheel 22 are respectively recorded as the third wheel 221 and the fourth wheel 222.

[0066] like Figure 5 As shown, the first wheel disc 311 and the second wheel disc 312 are both arranged on the driven shaft 3, wherein the first wheel disc 311 is located below the second wheel disc 312, and the first wheel disc 311 and the driven shaft 3 remain relatively fixed, the second wheel disc 312 can move along the axial direction of the driven shaft 3, and the second wheel disc 312 remains relatively positioned with the driven shaft 3 in the circumferential direction of the driven shaft 3, that is, the second wheel disc 312 cannot rotate circumferentially relative to the driven shaft 3.

[0067] The driven shaft 3 is sleeved with a first elastic member 61, wherein the first elastic member 61 may be a spring; the first elastic member 61 is used to provide a first elastic force to drive the two wheel discs of the driven wheel 31 to move closer to each other. Specifically, the first elastic member 61 is located above the second wheel disc 312 and is used to push the second wheel disc 312 downward.

[0068] like Fig.10 As shown, the third wheel disc 221 and the fourth wheel disc 222 are both arranged on the driving shaft 2, wherein the third wheel disc 221 is located below the fourth wheel disc 222, the fourth wheel disc 222 and the driving shaft 2 remain relatively fixed, the third wheel disc 221 can move along the axial direction of the driving shaft 2, and the third wheel disc 221 remains relatively positioned with the driving shaft 2 in the circumferential direction of the driving shaft 2, so as to rotate synchronously with the driving shaft 2.

[0069] A second elastic member is sleeved on the driving shaft 2, and the second elastic member can also be a spring. The second elastic member is used to provide a second elastic force to drive the two wheels of the driving wheel 22 away from each other. For example, the second elastic member is used to push the third wheel 221 downward.

[0070] The gearbox also includes a clutch mechanism, which is used to drive the two wheel discs of the driving wheel 22 to approach each other. In this embodiment, the clutch mechanism is equivalent to a lifting mechanism, which is mainly used to overcome the elastic force of the second elastic member to lift the third wheel disc 221 upward, and can be operated by the operator driving the lawn mower. This clutch mechanism has many applications and descriptions in some existing CVT gearboxes of automobiles, so no excessive description is made here.

[0071] When speeding up is required, the third wheel 221 is controlled to move upward through the clutch mechanism, so that the third wheel 221 overcomes the second elastic force of the second elastic member and moves closer to the fourth wheel 222, thereby increasing the tension of the belt 5, so that the rotation speed of the driven wheel 31 can be increased; when deceleration is required, the clutch mechanism is released. Without the effect of the clutch mechanism, the third wheel 221 can be reset downward driven by the second elastic force of the second elastic member to move away from the fourth wheel 222. At this time, the tension of the belt 5 is reduced and is in a relatively relaxed state, thereby slowing down the rotation speed of the driven wheel 31.

[0072] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. A CVT gearbox, comprising a gearbox, and a driving shaft, a driven shaft and an output shaft arranged on the gearbox, wherein the driving shaft is provided with an input wheel and a driving wheel in sequence, the driven shaft is provided with a driven wheel, and the driven wheel and the driving wheel are driven by a belt; the lower end of the driven shaft is driven by the output shaft through a gear set in the gearbox, characterized in that: The gearbox also includes a first retaining frame and two first bearings, wherein the first retaining frame is fixed on the gear box; the two first bearings are both mounted on the driven shaft, one end of the driven shaft is rotatably connected to the gear box through one of the first bearings, and the other end is rotatably connected to the first retaining frame through another first bearing; the driven wheel is located between the two first bearings.

2. A CVT gearbox according to claim 1, characterized in that: The first retaining frame includes at least one first support leg, and the first support leg is at least partially blocked outside the belt and is gap-matched with the belt.

3. A CVT gearbox according to claim 2, characterized in that: The first retaining frame includes three of the first legs, and the belt forms a first tangent point and a second tangent point at the tangent points with the driven wheel at the positions where the belt enters and exits the driven wheel, respectively. The belt and the driven wheel form a third tangent point at the tangent point between the first tangent point and the second tangent point, and the third tangent point is located on the perpendicular bisector of the line connecting the first tangent point and the second tangent point; three of the first legs, two of which are located at the first tangent point and the second tangent point, respectively, and the other is located at the third tangent point.

4. A CVT gearbox according to claim 2 or 3, characterized in that: The first retaining frame also includes a mounting portion arranged on the top of the first supporting leg, and the first bearing is mounted on the mounting portion.

5. A CVT transmission according to claim 1, characterized in that: The center line connecting the driving wheel and the driven wheel is parallel to the output shaft.

6. A CVT transmission according to claim 1, characterized in that: The distance between the center of the driven wheel and the central axis of the output shaft is A, wherein 55mm≤A≤75mm, and / or the distance between the center of the input wheel and the central axis of the output shaft is E, wherein 100mm≤E≤115mm.

7. A CVT transmission according to claim 1, characterized in that: The output shaft comprises two shaft sections, a differential gear is arranged between the two shaft sections, and a first gear meshing with the differential gear is arranged at one end of the shaft body close to the differential gear; the differential gear meshes with the gear set in the reduction box for transmission.

8. A CVT transmission according to claim 7, characterized in that: In the axial direction of the output shaft, the differential gear is located between the driving shaft and the driven shaft; and / or the driving shaft and the driven shaft are located on the same side of the output shaft.

9. The CVT transmission according to claim 1, characterized in that: The gearbox also includes a second retaining frame and two second bearings, wherein the second retaining frame is fixed to the gear box; the upper part of the driving shaft is rotatably connected to the retaining frame through one of the second bearings, and the lower part of the driving shaft is rotatably connected to the gear box through another second bearing; the driving wheel is located between the two second bearings; and the input wheel is located at the top of the driving shaft.

10. The CVT transmission according to claim 1, characterized in that: The driving wheel and the driven wheel are both movable pulleys, and the movable pulleys include two wheel discs that can move relative to each other in the axial direction and keep relative positioning in the circumferential direction, and the two wheel discs are spaced apart in the axial direction to form a wheel groove for the belt to be embedded, and the wheel groove gradually widens radially outward; wherein, The driven shaft is provided with a first elastic member, and the first elastic member is used to provide a first elastic force to drive the two wheel discs of the driven wheel to move closer to each other; The driving shaft is provided with a second elastic member, and the second elastic member is used to provide a second elastic force to drive the two wheel discs of the driving wheel away from each other; The gearbox also includes a clutch mechanism, which is used to drive the two wheel discs of the driving wheel to approach each other.

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