CN211525378U

CN211525378U - Power transmission device

Info

Publication number: CN211525378U
Application number: CN202020117305.1U
Authority: CN
Inventors: 潘江伟; 邓定红; 张立成; 张林江; 郑海刚
Original assignee: Zhejiang Meikeda Motorcycle Co ltd
Current assignee: Zhejiang Meikeda Motorcycle Co ltd
Priority date: 2020-01-03
Filing date: 2020-01-19
Publication date: 2020-09-18
Anticipated expiration: 2030-01-19
Also published as: CN111156262A

Abstract

The utility model provides a power transmission device belongs to mechanical transmission technical field. The torque transmission device solves the technical problems that the conventional power transmission device is easy to generate torque force to rotate when the rotation speed of an output shaft is greater than that of an input gear. This power transmission device includes input gear, clutch housing, output shaft, clutch element, clamp plate and elastic component, circumference has the derivation face one that a plurality of slopes set up on the clamp plate, its characterized in that, a plurality of top thrusters towards the clamp plate bulge have on the bottom plate of clutch element, top thrusters have the derivation face two that the slope set up, and top thrusters encircle the output shaft setting, and a plurality of top thrusters set up along clutch element circumference interval with a plurality of elastic component, and when the slew rate of output shaft was greater than input gear's slew rate, derivation face two can top derivation face one and make drive clutch piece and driven clutch piece loosen. The utility model discloses power transmission device's life can be improved.

Description

Power transmission device

Technical Field

The utility model belongs to the technical field of mechanical transmission, concretely relates to power transmission device.

Background

The motorcycle mostly adopts the normally closed clutch to engage or disengage the power transmission function. The structure of the existing normally closed clutch generally comprises a clutch shell, a clutch element arranged in the clutch shell, an output shaft inserted in the clutch element, an input gear rotationally sleeved on the output shaft and fixedly connected to one side of the clutch shell and a pressing plate slidably arranged at one end, far away from one end of the input gear, of the clutch element, wherein the clutch element comprises a cylindrical body and a circular base plate arranged at one end of the body, a plurality of driven clutch plates are arranged on the body, a plurality of driving clutch plates are arranged on the clutch shell, and the driving clutch plates and the driven clutch plates are alternately arranged. A plurality of elastic pieces are arranged between the pressure plate and the clutch element along the axial direction of the body, the inner ends of the elastic pieces are abutted against the pressure plate, the outer ends of the elastic pieces are abutted against the clutch element, and the elastic pieces can stretch and retract to drive the pressure plate to move along the axial direction of the body, so that the pressure contact or the release of the driving clutch plate and the driven clutch plate is realized. Under normal state, the elastic part is in a compressed state, the pressure plate has a tendency of moving towards the input gear, so that the pressure driving clutch plate and the driven clutch plate are in pressure contact, and the input gear can drive the output shaft to rotate through the clutch shell and the clutch element. When the input gear stops the power transmission, the push rod inserted in the output shaft is pushed by the operating mechanism to push the pressure plate, so that the pressure plate moves towards the direction far away from the input gear, and the driving clutch plate and the driven clutch plate are loosened to cut off the power transmission.

However, before the pressing plate is pushed by the push rod, the output shaft and the clutch element still keep high-speed operation under the inertia effect, so that the rotation rate of the output shaft is greater than that of the input gear and torsion rotation is generated, parts are easily abraded, a power transmission device or a power unit (such as an engine) is broken down, and the service life of the power transmission device is influenced.

Disclosure of Invention

The utility model discloses to the above-mentioned problem that prior art exists, provide a power transmission device, the utility model aims to solve the technical problem that: how to improve the service life of the power transmission device.

The purpose of the utility model can be realized by the following technical proposal:

a power transmission device comprises a clutch shell which is fixedly connected with an input gear and sleeved with a driving clutch plate, a cylindrical clutch element which is circumferentially fixed with an output shaft and sleeved with a driven clutch plate, a pressure plate connected with the clutch element and a plurality of elastic pieces which can enable the pressure plate and the clutch element to clamp the driving clutch plate and the driven clutch plate, wherein a plurality of obliquely arranged first guide surfaces are circumferentially arranged on the pressure plate, it is characterized in that a bottom plate of the clutch element is provided with a plurality of pushing platforms which protrude towards the pressure plate, the pushing table is provided with a second guide surface which is obliquely arranged, the pushing table is arranged around the output shaft, and a plurality of pushing tables and a plurality of elastic pieces are arranged at intervals along the circumferential direction of the clutch element, when the rotation rate of the output shaft is larger than that of the input gear, the second derivation surface can push against the first derivation surface to enable the driving clutch plate and the driven clutch plate to be released.

The working principle of this patent: when the rotation rate of the output shaft is greater than that of the input gear, namely when the input gear stops power transmission, the power transmission direction is converted into that the output shaft drives the clutch shell to rotate by the input gear, at the moment, the guide-out surface two of the clutch element pushes the guide-out surface one of the pressure plate, the force applied on the guide-out surface one by the guide-out surface two can be decomposed into radial rotating force and axial thrust, the radial rotating force can effectively reduce the rotation rate of the clutch element, and the axial thrust can push the pressure plate to overcome the elastic force of the elastic piece and move away from the base plate, so that the pressure contact between the driving clutch plate and the driven clutch plate is relieved, and the power transmission device fault caused by torque rotation is avoided. The pushing table is arranged around the output shaft, the elastic piece and the pushing table are arranged at intervals in the circumferential direction of the output shaft, the second guiding surface and the elastic piece are arranged near the central position of the pressing plate in a centralized mode, the force transmission effect between the clutch element and the elastic piece and the pressing plate three is improved, the external thrust borne by the pressing plate is increased, the outward moving speed of the pressing plate is accelerated, meanwhile, each elastic piece is located between a group of adjacent pushing tables, the axial and radial stress uniformity of the pressing plate can be improved, the pressing plate can stably move along the axial direction of the clutch element, and the quick release of pressure contact between the driving clutch plate and the driven clutch plate is facilitated, so that the abrasion between parts caused by torque rotation is remarkably reduced, and the service life of the power transmission.

In the power transmission device, the pressing plate is concavely provided with a plurality of grooves for mounting the elastic element towards the bottom plate, the groove bottom of each groove is provided with a waist-shaped hole, and the inner end of the elastic element abuts against the long-edge hole edges on the two sides of the waist-shaped hole. When the input gear transmits power to the output shaft and before the push rod pushes the pressing plate, the pressing plate rotates together with the clutch element under the driving of the clutch element, and the waist-shaped holes are formed to enable the elastic pieces to be in spaced fit with the groove walls of the grooves, so that the elastic pieces can move along the length direction of the waist-shaped holes when the pressing plate rotates to generate radial friction, and the elastic pieces can drive the driven clutch plate to be in pressure contact with or to be released from the driving clutch plate. Preferably, the length direction of the waist-shaped hole is perpendicular to the radial direction of the pressure plate, so that abrasion among parts is reduced, and the service life of the power transmission device is prolonged.

In foretell power transmission device, be equipped with a plurality of erection columns on the bottom plate, it is a plurality of the erection column passes a plurality of waist shape holes respectively, the erection column sets up along bottom plate circumference interval with the top push bench, power transmission device still including link firmly the push pedal of supporting in the erection column outer end, the outer end of elastic component with support the push pedal butt. The mounting post is parallel to the axial arrangement of the clutch element, so that the elastic part can be conveniently mounted, and meanwhile, the pressing plate can play a role in guiding when moving axially along the clutch element, so that the pressing plate can move axially along the mounting post conveniently. Preferably, the mounting column gradually contracts inwards from the inner end (i.e. the end on the bottom plate) of the mounting column to the outer end (i.e. the end fixedly connected with the abutting and pushing plate), the inner end is larger, the connection stability of the mounting column on the bottom plate can be guaranteed, meanwhile, the structural strength of the bottom plate is favorably improved, and the outer end is smaller, so that the mounting of the elastic piece and the axial movement of the pressing plate are facilitated.

In the above power transmission device, the pressure plate further has a first guide surface arranged obliquely, the pushing table has a second guide surface arranged obliquely, and when the input gear drives the output shaft to rotate, the second guide surface can push the first guide surface to increase the pressure contact force between the driving clutch plate and the driven clutch plate. The clutch element is driven to synchronously rotate by the clutch shell, the second leading-in surface abuts against the first leading-in surface and drives the pressure plate to move towards the bottom plate, so that the pressure contact force between the driving clutch plate and the driven clutch plate is increased, the power transmission efficiency of the output gear to the output shaft is improved, meanwhile, the abrasion between the driving clutch plate and the driven clutch plate is reduced, and the service life of the clutch plate is prolonged.

In the power transmission device, the pressure plate is provided with a plurality of lightening holes. The quality of the pressing plate can be reduced, so that when the first leading-out surface is abutted to the second leading-out surface, the pressing plate is pushed to move outwards more quickly, abrasion between parts is reduced, and the service life of the clutch plate is prolonged.

In the power transmission device, the lightening hole is a square hole, the lightening hole and the elastic piece are arranged at intervals along the circumferential direction of the pressing plate, and the first leading-out surface and the first leading-in surface are oppositely arranged on the hole walls on two sides of the lightening hole. The processing and preparation are convenient, the structural compactness of the pressing plate is improved, the structural strength of the pressing plate is favorably ensured, and meanwhile, the spatial arrangement of the pressing plate is convenient. And the first leading-out surface is arranged on the hole wall on one side of the lightening hole, when the input gear stops the stop force transmission and the clutch element and the pressure plate stop rotating, the second leading-out surface and the first leading-in surface are in a pressing state, the second leading-in surface and the first leading-in surface are separated from each other, the second leading-in surface and the first leading-in surface which are inserted into the lightening hole from the outer side of the pressure plate are convenient to push the first leading-in surface, the pressure plate rotates and enables the second leading-out surface to be abutted against the first leading-out surface, and therefore the pressure plate is pushed by external thrust to move towards the direction far away from the base plate, the driving clutch plate and the driven clutch plate are loosened.

Compared with the prior art, the utility model has the advantages of it is following:

1. when the rotation speed of the output shaft is greater than that of the input gear, the second guide surface abuts against the first guide surface of the pressure plate and can drive the pressure plate to move towards the direction far away from the base plate so as to enable the driving clutch plate to be loosened from the driven clutch plate, the rotation speed of the clutch element can be effectively reduced, and the power transmission device fault caused by torque rotation is avoided.

2. The pushing table is arranged around the output shaft, the elastic piece and the pushing table are arranged along the circumferential direction of the clutch element at intervals, the second guiding surface and the elastic piece are arranged near the central position of the pressing plate in a centralized mode, the external thrust force exerted on the pressing plate is increased, the outward moving speed of the pressing plate is increased, meanwhile, the axial and radial stress uniformity of the pressing plate can be improved, the pressing plate is guaranteed to move stably along the axial direction of the clutch element, abrasion between parts caused by torsion rotation is remarkably reduced, and the service life of the power transmission device is prolonged.

3. The first leading-out surface and the first leading-in surface are oppositely arranged on the hole walls on the two sides of the lightening hole, the structural compactness of the pressing plate is improved, the structural strength of the pressing plate is favorably ensured, and the power transmission device is convenient to overhaul.

Drawings

Fig. 1 is a schematic view of the overall structure of the embodiment of the present invention.

Fig. 2 is a schematic overall structure diagram of another view angle according to the embodiment of the present invention.

Fig. 3 is a cross-sectional view of an embodiment of the invention.

Fig. 4 is a cross-sectional view from another perspective of an embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a clutch element according to an embodiment of the present invention.

Fig. 6 is a schematic diagram of another perspective of a clutch element according to an embodiment of the present invention.

Fig. 7 is a schematic structural diagram of a pressing plate in the embodiment of the present invention.

Fig. 8 is a schematic structural diagram of another view angle of the pressing plate in the embodiment of the present invention.

In the figure, 1, an input gear; 2. a clutch housing; 3. an output shaft; 4. a clutch element; 41. a base plate; 41a, a through hole; 42. a body; 5. pressing a plate; 51a, a groove; 6. a pushing table; 61. a second leading-out surface; 62. a second lead-in surface; 63. a second inclined surface; 7. a boss; 7a, a waist-shaped hole; 71. leading-out surface I; 72. an avoidance surface; 73. a first lead-in surface; 74. a first inclined surface; 8. driving a clutch plate; 9. a driven clutch plate; 10. mounting a column; 11. an elastic member; 12. lightening holes; 13. and pushing the plate.

Detailed Description

The following are specific embodiments of the present invention and the accompanying drawings are used to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

As shown in fig. 1 to 4, the present embodiment includes a clutch housing 2, a clutch element 4 disposed in the clutch housing 2, an output shaft 3 inserted into the clutch element 4, an input gear 1 rotatably sleeved on the output shaft 3 and fixedly connected to one side of the clutch housing 2, a pressing plate 5 disposed at one end of the clutch element 4 far from the input gear 1, and three elastic members 11 disposed along an axial direction of the clutch element 4, where the elastic members 11 are compression springs. The clutch element 4 includes a cylindrical body 42, a base plate 41 having a circular plate shape is provided at one end of the body 42, a plurality of driven clutch plates 9 are provided on the body 42, a plurality of driving clutch plates 8 are provided on the clutch housing 2, and the driving clutch plates 8 and the driven clutch plates 9 are alternately arranged. The bottom plate 41 is provided with three mounting columns 10 positioned in the body 42, and the three mounting columns 10 are axially parallel to the body 42. The pressing plate 5 is in a circular plate shape and is connected with the base plate 41, the driving clutch plate 8 and the driven clutch plate 9 are positioned between the edge of the base plate 41 and the edge of the pressing plate 5, three bosses 7 facing the base plate 41 and positioned in the body 42 are arranged on the pressing plate 5, three grooves 51a which are concavely arranged towards the base plate 41 and are used for installing elastic pieces 11 are arranged on each boss 7, a kidney-shaped hole 7a for a mounting column 10 to pass through is arranged on the bottom of each groove 51a, the length direction of the kidney-shaped hole 7a is vertical to the radial direction of the pressing plate 5, the elastic pieces 11 are sleeved on the mounting columns 10, the outer ends of the mounting columns 10 are fixedly connected with the pushing plates 13 through bolts, the inner ends of the elastic pieces 11 abut against the long edge of the two sides of the kidney-shaped holes 7a, and, so that the pressure plate 5 can move axially along the body 42 by pressing the elastic member 11, thereby achieving the pressure contact or release of the driving clutch plate 8 and the driven clutch plate 9. Under normal conditions, the elastic member 11 is in a compressed state, and the pressure plate 5 has a tendency to move towards the input gear 1, so that the pressure-driven clutch plate 8 and the driven clutch plate 9 are in pressure contact, and power transmission from the input gear 1 to the output shaft 3 can be realized (namely, the input gear 1 drives the output shaft 3 to rotate through the clutch housing 2 and the clutch element 4).

As shown in fig. 4, 5 and 6, three pushing platforms 6 facing the pressing plate 5 and located in the body 42 are disposed on the bottom plate 41, the pushing platforms 6 are disposed around the output shaft 3, the pushing platforms 6 and the mounting posts 10 are disposed at intervals along the circumferential direction of the bottom plate 41, so that the pushing platforms 6 and the elastic members 11 are disposed at intervals along the circumferential direction of the clutch element 4, the number of the pushing platforms 6 is the same as that of the mounting posts 10, and the number of the elastic members 11 is the same as that of the mounting posts. Each top pushes up the platform 6 and all has the derivation face two 61 that the slope set up, make derivation face two 62 and elastic component 11 concentrate and set up near 5 central point of clamp plate puts, increase the external thrust that clamp plate 5 received for the outside rate of movement of clamp plate 5, can improve 5 axial of clamp plate and radial atress homogeneity simultaneously, guarantee clamp plate 5 is along 4 axial steady movements of clutch element, show the wearing and tearing between the spare part that reduce torsion gyration and cause, improve the life of this patent.

As shown in fig. 4, 7 and 8, the bosses 7 are arranged at intervals along the circumferential direction of the pressure plate 5, and each boss 7 is arranged between a group of two adjacent pushing platforms 6, and the boss 7 has a first inclined leading-out surface 71. When the rotation speed of the output shaft 3 is larger than that of the input gear 1, the second leading-out surface 61 abuts against the first leading-out surface 71 and can drive the pressure plate 5 to move towards the direction away from the base plate 41, so that the rotation speed of the clutch element 4 can be effectively reduced, the link between the driving clutch plate 8 and the driven clutch plate 9 can be released, and the fault caused by torque rotation can be avoided. The arrangement of the pushing platform 6 is beneficial to arranging the second leading-out surface 61 near the center of the pressure plate 5, the outward pushing action of the second leading-out surface 61 on the pressure plate 5 is obviously improved, and the pressure plate 5 is beneficial to rapidly moving outwards, so that the pressure contact between the driving clutch plate 8 and the driven clutch plate 9 is rapidly released.

The ejection table 6 is a square boss, and the boss 7 is an arc-shaped boss, so that the processing and the installation are convenient, and the structure optimization setting of the ejection table 6 and the boss 7 is facilitated. The second leading-out surface 61 is a side wall of the pushing platform 6, a side wall of the boss 7 is provided with an avoiding surface 72 which is arranged in parallel with a table top adjacent to the pushing platform 6, the first leading-out surface 71 is connected between the avoiding surface 72 and the table top of the boss 7, namely, the boss 7 is partially positioned above the pushing platform 6, the boss 7 is convenient to be lapped on the pushing platform 6, the boss 7 is ensured to be arranged between the adjacent pushing platforms 6, meanwhile, the arrangement of the avoiding surface 72 is beneficial to ensuring the butting of the second leading-out surface 61 and the first leading-out surface 71, the pressure plate 5 is ensured to move towards the direction far away from the bottom plate 41, and the faults caused by torsion rotation are.

Each pushing platform 6 is also provided with a leading-in surface two 62 which is obliquely arranged, each boss 7 is also provided with a leading-in surface one 73 which is obliquely arranged and is opposite to the leading-in surface two 62, when the input gear 1 drives the output shaft 3 to rotate, the leading-in surface two 62 is abutted against the leading-in surface one 73 and can drive the pressing plate 5 to move towards the base plate 41 so as to increase the pressure contact force of the driving clutch plate 8 and the driven clutch plate 9, the clutch shell 2 can be ensured to drive the clutch element 4 to synchronously rotate, meanwhile, the abrasion between the driving clutch plate 8 and the driven clutch plate 9 is favorably reduced, and the service life of the clutch plates is prolonged.

The second lead-in surface 62 and the second lead-out surface 61 on each pushing platform 6 are respectively arranged on the two opposite side walls of the pushing platform 6, and the inclination direction of the second lead-in surface 62 is the same as that of the second lead-out surface 61. The first leading-in surface 73 and the first leading-out surface 71 of each boss 7 are respectively arranged on two opposite side walls of the boss 7, and the inclination direction of the first leading-in surface 73 is the same as that of the second leading-out surface 61. The structure design of each leading-in surface and each leading-out surface is simple and reasonable, and when the leading-out surface II 61 is abutted against the leading-out surface I71 or the leading-in surface II 62 is abutted against the leading-in surface I73, the pressure plate 5 is respectively subjected to the outward pushing force or the inward pulling force of the clutch element 4, so that the pressure plate 5 is ensured to respectively move towards the direction away from the bottom plate 41 or towards the bottom plate 41.

Three square lightening holes 12 are formed in the pressing plate 5, so that the quality of the pressing plate 5 can be reduced, the pressing plate 5 is pushed to move outwards more quickly when the first leading-out surface 71 is abutted to the second leading-out surface 61, abrasion between parts is reduced, and the service life of the clutch disc is prolonged. The lightening holes 12 and the bosses 7 are arranged at intervals along the circumferential direction of the pressing plate 5, namely each lightening hole 12 is formed between a group of adjacent bosses 7, and a group of opposite hole walls of the lightening holes 12 are respectively a leading-out surface I71 and a leading-in surface I73, so that the processing and the preparation are convenient, the structural compactness of the pressing plate 5 is improved, the structural strength of the pressing plate 5 is favorably ensured, and the spatial arrangement of the pressing plate 5 is facilitated. When the input gear 1 stops power transmission and the clutch element 4 and the pressure plate 5 stop rotating, the second leading-out surface 61 and the first leading-out surface 71 are in a pressing state, the second leading-in surface 62 and the first leading-in surface 73 are separated from each other, so that the second leading-in surface 62 and the first leading-in surface 73 inserted into the lightening hole 12 from the outer side of the pressure plate 5 are convenient to push the first leading-in surface 73, the pressure plate 5 rotates, the second leading-out surface 61 is abutted to the first leading-out surface 71, the pressure plate 5 is moved in a direction away from the base plate 41 under the action of external thrust, the driving clutch plate 8 and the driven clutch plate 9 are released, and the input component and the output component of the embodiment are convenient to be respectively.

The inclination angle of the second leading-in surface 62 is smaller than that of the second leading-out surface 61, and the inclination angle of the first leading-in surface 73 is smaller than that of the first leading-out surface 71, so that the external thrust of the pressure plate 5 on the clutch element 4 is larger, and when the rotation speed of the output shaft 3 is larger than that of the input gear 1, the fault caused by torsion rotation can be effectively avoided.

One end of the second leading-in surface 62 is connected with the table top of the pushing table 6, the other end of the second leading-in surface 62 is connected with the bottom plate 41 through a second inclined surface 63, the second inclined surface 63 is connected with the second leading-in surface 62 at an obtuse angle, one end of the first leading-in surface 73 is connected with the table top of the boss 7, the other end of the first leading-in surface 73 is adjacent to the pressing plate 5 through a first inclined surface 74, the first inclined surface 74 is connected with the first leading-in surface 73 at an obtuse angle, namely the second leading-in surface 62 is connected with the second inclined surface 63 to form a hook-shaped structure, and the first leading-in surface 73 is connected with the first inclined surface 74 to form. Meanwhile, through holes 41a are formed between adjacent pushing platforms 6 on the bottom plate 41, so that the installation is convenient, the arrangement of the second inclined surface 63 can prevent the bosses 7 from sliding out of the corresponding through holes 41a, and the abutting of the second guiding surface 62 and the first guiding surface 73 is ensured.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Although 1, the input gear, is used more herein; 2. a clutch housing; 3. an output shaft; 4. a clutch element; 41. a base plate; 41a, a through hole; 42. a body; 5. pressing a plate; 51a, a groove; 6. a pushing table; 61. a second leading-out surface; 62. a second lead-in surface; 63. a second inclined surface; 7. a boss; 7a, a waist-shaped hole; 71. leading-out surface I; 72. an avoidance surface; 73. a first lead-in surface; 74. a first inclined surface; 8. driving a clutch plate; 9. a driven clutch plate; 10. mounting a column; 11. an elastic member; 12. lightening holes; 13. push plates, etc., but do not exclude the possibility of using other terms. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed in a manner that is inconsistent with the spirit of the invention.

Claims

1. A power transmission device comprises a clutch shell (2) fixedly connected with an input gear (1) and sleeved with a driving clutch plate (8), a cylindrical clutch element (4) circumferentially fixed with an output shaft (3) and sleeved with a driven clutch plate (9), a pressure plate (5) connected to the clutch element (4), and a plurality of elastic members (11) capable of enabling the pressure plate (5) and the clutch element (4) to clamp the driving clutch plate (8) and the driven clutch plate (9), wherein a plurality of obliquely arranged first guide surfaces (71) are circumferentially arranged on the pressure plate (5), the power transmission device is characterized in that a plurality of pushing tables (6) protruding towards the pressure plate (5) are arranged on a bottom plate (41) of the clutch element (4), the pushing tables (6) are provided with obliquely arranged second guide surfaces (61), and the pushing tables (6) are arranged around the output shaft (3), and a plurality of the pushing platforms (6) and a plurality of elastic pieces (11) are arranged at intervals along the circumferential direction of the clutch element (4), and when the rotation rate of the output shaft (3) is greater than that of the input gear (1), the second guide surface (61) can push the first guide surface (71) to enable the driving clutch plate (8) and the driven clutch plate (9) to be loosened.

2. The power transmission device according to claim 1, wherein the pressure plate (5) is provided with a plurality of grooves (51a) for mounting the elastic members (11) in a concave manner towards the bottom plate (41), the bottoms of the grooves (51a) are provided with waist-shaped holes (7a), and the inner ends of the elastic members (11) abut against the long-edge hole edges on two sides of the waist-shaped holes (7 a).

3. The power transmission device according to claim 2, wherein a plurality of mounting posts (10) are arranged on the bottom plate (41), the mounting posts (10) respectively penetrate through a plurality of waist-shaped holes (7a), the mounting posts (10) and the pushing platform (6) are arranged along the circumferential direction of the bottom plate (41) at intervals, the power transmission device further comprises a pushing plate (13) fixedly connected to the outer end of the mounting posts (10), and the outer end of the elastic member (11) is abutted to the pushing plate (13).

4. The power transmission device according to any one of claims 1 to 3, wherein the pressure plate (5) further has a first obliquely arranged leading surface (73), and the pushing table (6) has a second obliquely arranged leading surface (62), and when the input gear (1) rotates the output shaft (3), the second leading surface (62) can push the first leading surface (73) to increase the pressure contact force of the driving clutch plate (8) and the driven clutch plate (9).

5. The power transmission device as claimed in claim 4, wherein the pressure plate (5) is provided with a plurality of lightening holes (12).

6. The power transmission device as claimed in claim 5, wherein the lightening hole (12) is a square hole, the lightening hole (12) and the elastic member (11) are arranged at intervals along the circumferential direction of the pressure plate (5), and the leading-out surface one (71) and the leading-in surface one (73) are arranged on the wall of the hole on both sides of the lightening hole (12) opposite to each other.