A strength training device

Abstract

The present invention discloses a strength training device, comprising a frame; the strength training device also comprises: a speed change device, comprising a driving motor arranged on the frame and a transmission arranged on the frame and connected to the driving motor, the transmission outputs the output of the driving motor after deceleration; a differential connected to the transmission, having a first output shaft and a second output shaft, the differential can convert the output of the transmission after speed change into an asymmetric force output from the first output shaft and the second output shaft; a wire take-up device, comprising a wire take-up box, the wire take-up box comprising a lower wire take-up box and an upper wire take-up box, the two wire take-up boxes are respectively connected to the first output shaft and the second output shaft. The present invention can convert the output of a driving motor into two force outputs, has a simple structure and low cost.

Description

Technical Field

[0001] The invention relates to a sports apparatus, more specifically to a strength training apparatus. Background Art

[0002] Most strength training equipment are heavy mechanical frames equipped with a variety of weights, and the weight change is not flexible. Therefore, strength training equipment that uses motors to control the pulling force has emerged. This type of strength training equipment usually includes a pedal, a force control part located on the left and right sides of the pedal, and a pull rope connected to the force control part. The force control part is mainly controlled by a motor. However, the current movement modes of strength training equipment are all separated from the left and right, that is, each force control part is driven by an independent motor, and two motors need to be set up, which is not only complex in structure but also high in cost. Summary of the invention

[0003] The present invention provides a strength training device to solve the technical problem that the existing strength training devices have left and right separated movement modes, which is not only complex in structure but also high in cost.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is to design a strength training device, including a frame; the strength training device also includes:

[0005] A speed change device, comprising a driving motor disposed on the frame and a transmission disposed on the frame and connected to the driving motor, wherein the transmission reduces the speed of the output of the driving motor and then outputs the output;

[0006] A differential connected to the transmission, having a first output shaft and a second output shaft, wherein the differential can convert the output of the transmission after the speed change into an asymmetric force to be output from the first output shaft and the second output shaft;

[0007] The wire-taking device comprises a wire-taking box, wherein the wire-taking box comprises a lower wire-taking box and an upper wire-taking box, and the two wire-taking boxes are respectively connected to the first output shaft and the second output shaft.

[0008] The transmission includes a first reduction gear set connected to the driving motor and a second reduction gear set connected to the first reduction gear set.

[0009] The first reduction gear set comprises:

[0010] A driving gear, which is fixed to the output shaft of the driving motor;

[0011] a first reduction gear meshing with the driving gear;

[0012] The second reduction gear set comprises:

[0013] Second main reduction gear;

[0014] a second slave reduction gear meshing with the second main reduction gear;

[0015] The transmission also includes a first reduction gear shaft, both ends of which are supported on the frame and can rotate relative to the frame, and the first reduction gear and the second main reduction gear are fixed on the first reduction gear shaft.

[0016] The first reduction gear and the second main reduction gear are double gears formed in one piece and distributed up and down.

[0017] The differential comprises:

[0018] a differential housing connected to the frame and rotatable relative to the frame; the second reduction gear is sleeved on the differential housing and fixedly connected to the differential housing; the first output shaft and the second output shaft are both rotatably connected to the differential housing;

[0019] A first differential gear, which is fixedly connected to the first output shaft;

[0020] A second differential gear, fixedly connected to the second output shaft;

[0021] a first planetary gear meshing with the first differential gear;

[0022] a second planetary gear meshing with the second differential gear and the first planetary gear;

[0023] The first planetary gear and the second planetary gear can rotate together with the differential case, and the first planetary gear and the second planetary gear can also rotate relative to the differential case.

[0024] The differential also includes:

[0025] A first planetary shaft, which is fixedly connected to the differential housing; the first planetary gear is sleeved on the first planetary shaft and can rotate relative to the first planetary shaft;

[0026] The second planetary shaft is fixedly connected to the differential housing; the second planetary gear is sleeved on the second planetary shaft and can rotate relative to the second planetary shaft.

[0027] The second output shaft is located directly above the first output shaft, the first differential gear is located at the upper end of the first output shaft, and the second differential gear is located at the lower end of the second output shaft; the first planetary shaft and the second planetary shaft are located on the sides of the first differential gear and the second differential gear;

[0028] There is a gap between the first differential gear and the second differential gear, the height of the first planetary gear is lower than the lower surface of the second differential gear, and the height of the second differential gear is lower than the upper surface of the first planetary gear and higher than the upper surface of the first differential gear.

[0029] The differential also includes:

[0030] A differential shaft, which is rotatably connected to the first differential gear and the second differential gear, the bottom of the differential shaft is fixedly connected to the bottom surface of the frame, and the top of the second output shaft is rotatably connected to the frame;

[0031] The differential housing comprises:

[0032] A lower housing, wherein a first bearing is disposed at the center of the lower housing; the first bearing is sleeved on the first output shaft and can rotatably connect the first output shaft and the lower housing;

[0033] An upper housing, wherein a second bearing is disposed in the center of the upper housing; the second bearing is sleeved on the second output shaft and can rotatably connect the second output shaft and the upper housing;

[0034] The differential shaft is rotatably connected to the second differential gear, the first differential gear and the first output shaft respectively through a third bearing, a fourth bearing and a fifth bearing from top to bottom.

[0035] The lower wire take-up box and the upper wire take-up box are respectively arranged at the lower end and the upper end of the differential, the lower wire take-up box is sleeved on the first output shaft and fixedly connected to the first output shaft, and the upper wire take-up box is sleeved on the second output shaft and fixedly connected to the second output shaft.

[0036] The speed change device, the differential and the wire take-up device are all located in the center of the frame, and the strength training device also includes pedal parts arranged on the left and right sides of the frame.

[0037] The strength training apparatus of the present invention is provided with a speed change device, a differential and a wire take-up device. A driving motor and a transmission are provided in the speed change device. The transmission outputs the driving motor after deceleration. The differential is connected to the transmission and has a first output shaft and a second output shaft. The differential can convert the output of the transmission after speed change into an asymmetric force to be output from the first output shaft and the second output shaft. The wire take-up device includes a wire take-up box, and the wire take-up box includes a lower wire take-up box and an upper wire take-up box. The two wire take-up boxes are connected to the first output shaft and the second output shaft respectively. Thus, the output of a driving motor can be converted into two forces for output, so that the lower wire take-up box and the upper wire take-up box can be controlled, and then the tension of the pull rope connected to the lower wire take-up box and the upper wire take-up box can be controlled. Compared with the existing two sets of drives, the structure is not only simple, but also the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention is described in detail below with reference to the embodiments and accompanying drawings, wherein:

[0039] Figure 1 is a structural diagram of the strength training apparatus of the present invention;

[0040] Figure 2 It is a structural diagram of a speed change device, a differential and a wire take-up device of the strength training apparatus of the present invention;

[0041] Figure 3 yes Figure 2 sectional view of

[0042] Figure 4 yes Figure 2 The structural diagram after removing the upper rack;

[0043] Figure 5 yes Figure 2 The structural diagram from another perspective after removing the upper rack;

[0044] Figure 6 yes Figure 4 The structural diagram after removing the upper junction box and the upper housing of the differential;

[0045] Figure 7 yes Figure 6 The main view;

[0046] Figure 8 is a perspective view of a transmission of the present invention;

[0047] Fig. 9 is an exploded view of the differential of the present invention;

[0048] Fig.10 It is a structural diagram of the upper shell of the upper take-up box of the present invention;

[0049] Fig.11 It is a structural diagram of the lower shell of the lower take-up box of the present invention. DETAILED DESCRIPTION

[0050] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings:

[0051] See also Figures 1 to 11 The strength training device of the present invention comprises a strength control part 9, pedals 8 located on both sides of the strength control part 9 and a pull rope hole 7 arranged on the outside of the pedal. The pull rope is connected to the strength control part 9 through the pull rope hole 7. The pull rope can be pulled by overcoming the force of the strength control part on the pull rope, thereby achieving the purpose of strength training.

[0052] The force control unit 9 includes a frame 1, a speed change device 2, a differential 3 and a wire take-up device 4. Among them:

[0053] The frame 1 includes an upper frame 11 and a lower frame 12 .

[0054] The speed change device 2 comprises a driving motor 21 and a transmission 22. The driving motor comprises one, which is arranged on the frame. The driving motor 21 has a motor output shaft 211.

[0055] The transmission 22 is arranged on the frame and connected to the drive motor. The transmission outputs the drive motor after deceleration. In this specific embodiment, the transmission 22 includes a first reduction gear set 221 connected to the drive motor and a second reduction gear set 222 connected to the first reduction gear set. That is, the output of the drive motor is output after being decelerated twice. The speed ratio of the first reduction gear set and the speed ratio of the second reduction gear set are both greater than 1 and less than 6.

[0056] The first reduction gear set 221 includes a driving gear 2211 and a first reduction gear 2212, wherein the driving gear 2211 is fixed on the output shaft of the driving motor and the first reduction gear 2212 is meshed with the driving gear.

[0057] The second reduction gear set 222 includes a second main reduction gear 2221 and a second secondary reduction gear 2222. The second secondary reduction gear 2222 is meshed with the second main reduction gear. The second main reduction gear 2221 and the first reduction gear 2212 can be connected by meshing, but the meshing connection will cause the second main reduction gear and the second secondary reduction gear to be large in size and occupy a large space. Therefore, in this specific embodiment, the transmission also includes a first reduction gear shaft 223, both ends of the first reduction gear shaft 223 are supported on the frame and can rotate relative to the frame, and the first reduction gear and the second main reduction gear are fixed on the first reduction gear shaft. In this way, the second main reduction gear rotates synchronously with the first reduction gear, and the size of the second main reduction gear can be made smaller, the structure is compact, and the space occupied is also small. In this specific embodiment, the first reduction gear and the second main reduction gear are double gears formed in one piece and distributed up and down. The second main reduction gear extends downward from the center of the first reduction gear, so that the manufacturing is simpler and the structure is more compact.

[0058] In this specific embodiment, both ends of the first reduction gear shaft are supported between the upper frame and the lower frame through bearings, so that the first reduction gear shaft can rotate relative to the frame.

[0059] The driving gear, the first reduction gear, the second main reduction gear and the second secondary reduction gear are all arranged in a horizontal direction, and the driving gear, the first reduction gear, the second main reduction gear and the second secondary reduction gear are spur gears, which are easier to manufacture and more convenient to install.

[0060] The diameter of the driving gear is smaller than the diameter of the first reduction gear, and the diameter of the second main reduction gear is smaller than the diameter of the first reduction gear and the diameter of the second secondary reduction gear. The specific parameters of the driving gear, the first main reduction gear, the second main reduction gear and the second secondary reduction gear can be selected according to actual needs.

[0061] The speed change device of the present invention has a compact structure through the structural design of the driving gear, the first reduction gear, the second main reduction gear and the second slave reduction gear, and has a smaller space size than the existing belt chain transmission. At the same time, the transmission is more stable and the transmission efficiency is higher.

[0062] The present invention provides a driving motor and a transmission connected to the driving motor, and uses the transmission to reduce the output of the driving motor and then output it, so as to provide power for the strength training device. Moreover, the transmission includes a first reduction gear set connected to the driving motor and a second reduction gear set connected to the first reduction gear set. By changing the existing belt chain transmission into a gear transmission, and a two-stage gear transmission consisting of a first reduction gear set and a second reduction gear set, the output of the motor can be perfectly matched to the requirements of the strength training device after being transmitted by the gear set. The structure is compact, the space occupied is small, the transmission is stable, and the transmission efficiency is high.

[0063] The differential 3 is connected to the transmission and has a first output shaft and a second output shaft. The differential can convert the output of the transmission after speed change into an asymmetric force and output it from the first output shaft and the second output shaft.

[0064] In this specific embodiment, the differential 3 includes a differential housing 31 , a first output shaft 32 , a second output shaft 33 , a first differential gear 34 , a second differential gear 35 , a first planetary gear 36 , a second planetary gear 37 , a first planetary shaft 38 , a second planetary shaft 39 and a differential shaft 30 .

[0065] The differential housing 31 is connected to the frame and can rotate relative to the frame. The second slave reduction gear is sleeved on the differential housing and fixedly connected to the differential housing. A recessed slot 311 is provided on the outer surface of the differential housing 31. A locking protrusion 312 is provided on the second slave reduction gear 2222, and the locking protrusion 312 is locked in the slot 311 to achieve a fixed connection between the second slave reduction gear and the differential housing.

[0066] The differential housing 31 includes a lower housing 313, an upper housing 314, and a middle housing 315 connecting the upper housing and the lower housing. A first bearing 3131 is provided at the center of the lower housing 313, and a second bearing 3141 is provided at the center of the upper housing 314. In this specific embodiment, the second slave reduction gear 2222 is clamped on the lower housing 313 of the differential.

[0067] The first output shaft 32 is rotatably connected to the differential housing. In this specific embodiment, the first bearing 3131 is sleeved on the first output shaft and rotatably connects the first output shaft and the lower housing.

[0068] The first differential gear 33 is fixedly connected to the first output shaft.

[0069] The second output shaft 34 is rotatably connected to the differential housing. In this specific embodiment, the second bearing sleeve is rotatably connected to the second output shaft and the upper housing.

[0070] In this specific embodiment, the axes of the first output shaft and the second output shaft are on the same line.

[0071] The second differential gear 35 is fixedly connected to the second output shaft.

[0072] The first planetary gear 36 meshes with the first differential gear.

[0073] The second planetary gears 37 mesh with the second differential gear and the first planetary gears.

[0074] The first planetary gear and the second planetary gear can rotate together with the differential case, and at the same time, the first planetary gear and the second planetary gear can also rotate relative to the differential case.

[0075] The first planetary shaft 38 is fixedly connected to the differential housing 31 ; the first planetary gear 36 is sleeved on the first planetary shaft 38 and can rotate relative to the first planetary shaft.

[0076] The second planetary shaft 39 is fixedly connected to the differential housing 31 ; the second planetary gear 37 is sleeved on the second planetary shaft and can rotate relative to the second planetary shaft.

[0077] In this specific embodiment, the first planetary shaft 38 and the second planetary shaft 39 are arranged in parallel with the first output shaft 32 and the second output shaft 34, and both ends of the first planetary shaft and the second planetary shaft are fixed to the upper shell 314 and the lower shell 313 respectively.

[0078] The second output shaft 34 is located directly above the first output shaft 32 , the first differential gear 33 is located at the upper end of the first output shaft 32 , and the second differential gear 35 is located at the lower end of the second output shaft 34 ; the first planetary shaft 38 and the second planetary shaft 39 are located on the sides of the first differential gear 33 and the second differential gear 35 .

[0079] There is a gap between the first differential gear 33 and the second differential gear 35, the height of the first planetary gear is lower than the lower surface of the second differential gear, and the height of the second differential gear is lower than the upper surface of the first planetary gear and higher than the upper surface of the first differential gear. Thus, the first differential gear, the second differential gear, the first planetary gear and the second planetary gear can be arranged more closely.

[0080] The differential shaft 30 is rotatably connected to the first differential gear 33 and the second differential gear 34. The bottom of the differential shaft is fixedly connected to the bottom surface of the frame, and the top of the second output shaft 34 is rotatably connected to the frame. The differential shaft and the second output shaft cooperate to support the differential.

[0081] The differential shaft 30 is rotatably connected to the second differential gear, the first differential gear and the first output shaft respectively through the third bearing 301 , the fourth bearing 302 and the fifth bearing 303 from top to bottom.

[0082] The first differential gear, the second differential gear, the first planetary gear and the second planetary gear are all spur gears, which are easy to manufacture and install.

[0083] The working principle of the differential of the present invention is as follows: when the first differential gear and the second differential gear rotate at the same speed, the differential case rotates at the same speed as the first differential gear and the second differential gear, and the first planetary gear and the second planetary gear revolve with the differential case. When the first differential gear and the second differential gear rotate at different speeds, the differential case rotates, and the first planetary gear and the second planetary gear revolve with the differential case, while the first planetary gear and the second planetary gear rotate on their own, thereby achieving differential rotation between the first differential gear and the second differential gear.

[0084] The differential of the present invention is provided with a first output shaft, a first differential gear, a second output shaft, a second differential gear, a first planetary gear and a second planetary gear. The first output shaft and the second output shaft are both rotatably connected to the differential housing; the first differential gear is fixedly connected to the first output shaft; the second differential gear is fixedly connected to the second output shaft; the first planetary gear is meshed with the first differential gear; the second planetary gear is meshed with the second differential gear and the first planetary gear; the first planetary gear and the second planetary gear can rotate together with the differential housing, and at the same time, the first planetary gear and the second planetary gear can also rotate relative to the differential housing. Thus, the force transmitted to the differential housing by a single motor can be output through the first output shaft and the second output shaft, so that the strength training equipment can be provided with only one motor and output two groups of forces through the differential, and the structure is more compact, the cost is lower, and the space occupied is also smaller.

[0085] The differential structure of the present invention is compact and simple. By utilizing the torque of a single motor and outputting two groups of forces through the differential, the spatial structure of the entire strength training device is further optimized, while reducing the product manufacturing cost.

[0086] The drive gear on the main shaft of the drive motor outputs the motor torque, which is transmitted to the differential housing of the differential through the transmission. The first differential gear and the second differential gear receive two sets of pulling forces transmitted by the external pull rope, and form an action force and a reaction force with the force output by the drive motor. The torque output by the drive motor and the two sets of external pulling forces are acted on by the differential device. The two sets of external pulling forces output different torques, thereby outputting a set of asymmetric forces to meet the diversity of strength training.

[0087] The wire take-up device 4 includes a wire take-up box 41, which includes a lower wire take-up box 411 and an upper wire take-up box 412, and the two wire take-up boxes are connected to the first output shaft and the second output shaft respectively. The lower wire take-up box and the upper wire take-up box are respectively arranged at the lower end and the upper end of the differential, the lower wire take-up box 411 is sleeved on the first output shaft 32 and fixedly connected to the first output shaft, and the upper wire take-up box is sleeved on the second output shaft 34 and fixedly connected to the second output shaft.

[0088] The upper take-up box and the lower take-up box are mainly used to connect with the pull ropes on the left and right sides to retract and release the pull ropes.

[0089] The side of the lower wire take-up box 411 is provided with a first wire winding groove 4111 which is recessed inwards, and the side of the upper wire take-up box 412 is provided with a second wire winding groove 4121 which is recessed inwards. The first wire winding groove and the second wire winding groove are mainly used to receive the pull rope.

[0090] The lower wire receiving box 411 includes a lower wire receiving box upper shell 4119 and a lower wire receiving box lower shell 4118, and the lower wire receiving box lower shell 4118 is fixedly connected to the lower wire receiving box upper shell; a first wire fixing gap 4117 and a first wire fixing groove 4116 communicating with the first wire fixing gap are formed between the lower wire receiving box upper shell and the lower wire receiving box lower shell.

[0091] The upper wire taking-up box 412 comprises an upper wire taking-up box upper shell 4129 and an upper wire taking-up box lower shell 4128, and the upper wire taking-up box lower shell 4128 is fixedly connected to the upper wire taking-up box upper shell; a second wire fixing gap 4127 and a second wire fixing groove 4126 communicating with the second wire fixing gap are formed between the upper wire taking-up box upper shell and the upper wire taking-up box lower shell.

[0092] The first wire fixing groove and the second wire fixing groove are respectively located in the first wire winding groove and the second wire winding groove.

[0093] By setting the first wire fixing gap and the first wire fixing groove and the second wire fixing gap and the second wire fixing groove, the ends of the pull rope can be fixed on the lower wire taking-up box and the upper wire taking-up box, so as to facilitate the collection and release of the pull rope in the wire taking-up box.

[0094] In this specific embodiment, the first wire fixing groove and the second wire fixing groove are respectively arranged on the upper shell of the wire receiving box and the lower shell of the lower wire receiving box.

[0095] In order to make the wire take-up box better for taking up and releasing the pull rope, the wire take-up device further includes a first wire frame 42, a first wire wheel 43, a second wire frame 44 and a second wire wheel 45. Wherein:

[0096] The first wire rack 42 is disposed on the frame and located on the side of the lower wire take-up box.

[0097] The first wire wheel 43 is arranged on the first wire frame and can rotate relative to the first wire frame; a first wire groove 431 is arranged on the side of the first wire wheel, the first wire wheel is arranged opposite to the first winding groove, and the height of the first wire wheel is the same as the height of the first winding groove.

[0098] The second wire rack 44 is disposed on the frame and located on the side of the upper wire take-up box.

[0099] The second wire wheel 45 is arranged on the second wire frame and can rotate relative to the second wire frame; a second wire groove 451 is arranged on the side of the second wire wheel, the second wire wheel is arranged opposite to the second winding groove, and the height of the second wire wheel is the same as the height of the second winding groove.

[0100] The arrangement of the first wire wheel and the second wire wheel allows the rope to be pulled in and out horizontally along the first winding groove and the second winding groove, and the rope will not be separated from the first winding groove or the second winding groove due to height difference.

[0101] In this specific embodiment, the first wire rack 42 and the second wire rack 44 are arranged opposite to each other on the left and right sides of the wire take-up box, and the first wire wheel is located on the tangent of the first winding groove, and the second wire wheel is located on the tangent of the second winding groove, so as to facilitate the retraction and release of the pull rope.

[0102] Further, a third wire wheel 46 facing the first wire wheel is provided below the second wire frame 44, and the third wire wheel is provided with a third wire groove 461. The third wire wheel is mainly used to facilitate the pulling rope to be led down from the second wire wheel, so as to facilitate the wiring from the bottom.

[0103] To prevent the pull rope from falling off the guide wheel, the first guide wheel 43 is further provided with a first anti-falling column 432 located between the two side surfaces of the first guide groove; the second guide wheel 45 is further provided with a second anti-falling column 452 located between the two side surfaces of the second guide groove. The second guide wheel 46 is further provided with a third anti-falling column 462 located between the two side surfaces of the third guide groove.

[0104] The invention arranges the upper take-up box and the lower take-up box at the upper and lower ends of the differential respectively, so that the structure is very compact. In combination with the first wire pulley, the second wire pulley and the third wire pulley, it is more conducive to the routing and retraction of the pull rope.

[0105] The present invention provides an upper wire take-up box and a lower wire take-up box, and the lower wire take-up box and the upper wire take-up box are respectively arranged at the lower end and the upper end of the differential, the differential has a first output shaft and a second output shaft, the lower wire take-up box is sleeved on the first output shaft and fixedly connected to the first output shaft, and the upper wire take-up box is sleeved on the second output shaft and fixedly connected to the second output shaft. The wire take-up box and the differential are perfectly combined, the structure is compact, and the upper wire take-up box and the lower wire take-up box are linked together through the differential.

[0106] The strength training apparatus of the present invention is provided with a speed change device, a differential and a wire take-up device. A driving motor and a transmission are provided in the speed change device. The transmission outputs the driving motor after deceleration. The differential is connected to the transmission and has a first output shaft and a second output shaft. The differential can convert the output of the transmission after speed change into an asymmetric force to be output from the first output shaft and the second output shaft. The wire take-up device includes a wire take-up box, and the wire take-up box includes a lower wire take-up box and an upper wire take-up box. The two wire take-up boxes are connected to the first output shaft and the second output shaft respectively. Thus, the output of a driving motor can be converted into two forces for output, so that the lower wire take-up box and the upper wire take-up box can be controlled, and then the tension of the pull rope connected to the lower wire take-up box and the upper wire take-up box can be controlled. Compared with the existing two sets of drives, the structure is not only simple, but also the cost is low.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A strength training device, comprising a frame; characterized in that: The strength training apparatus further comprises: A speed change device, comprising a driving motor disposed on the frame and a transmission disposed on the frame and connected to the driving motor, wherein the transmission reduces the speed of the output of the driving motor and then outputs the output; A differential connected to the transmission, having a first output shaft and a second output shaft, wherein the differential can convert the output of the transmission after the speed change into an asymmetric force to be output from the first output shaft and the second output shaft; A wire taking-up device, comprising a wire taking-up box, wherein the wire taking-up box comprises a lower wire taking-up box and an upper wire taking-up box, and the two wire taking-up boxes are connected to the first output shaft and the second output shaft respectively; The transmission includes a first reduction gear set connected to the drive motor and a second reduction gear set connected to the first reduction gear set; The first reduction gear set comprises: A driving gear, which is fixed to the output shaft of the driving motor; a first reduction gear meshing with the driving gear; The second reduction gear set comprises: Second main reduction gear; a second slave reduction gear meshing with the second main reduction gear; The transmission further comprises a first reduction gear shaft, both ends of which are supported on the frame and can rotate relative to the frame, and the first reduction gear and the second main reduction gear are fixed on the first reduction gear shaft; The first reduction gear and the second main reduction gear are integrally formed double gears distributed up and down; The differential comprises: a differential housing connected to the frame and rotatable relative to the frame; the second reduction gear is sleeved on the differential housing and fixedly connected to the differential housing; the first output shaft and the second output shaft are both rotatably connected to the differential housing; A first differential gear, which is fixedly connected to the first output shaft; A second differential gear, fixedly connected to the second output shaft; a first planetary gear meshing with the first differential gear; a second planetary gear meshing with the second differential gear and the first planetary gear; The first planetary gear and the second planetary gear can rotate together with the differential case, and the first planetary gear and the second planetary gear can also rotate relative to the differential case.

2. The strength training device according to claim 1, characterized in that: The differential also includes: A first planetary shaft, which is fixedly connected to the differential housing; the first planetary gear is sleeved on the first planetary shaft and can rotate relative to the first planetary shaft; The second planetary shaft is fixedly connected to the differential housing; the second planetary gear is sleeved on the second planetary shaft and can rotate relative to the second planetary shaft.

3. The strength training apparatus according to claim 2, characterized in that: The second output shaft is located directly above the first output shaft, the first differential gear is located at the upper end of the first output shaft, and the second differential gear is located at the lower end of the second output shaft; the first planetary shaft and the second planetary shaft are located on the sides of the first differential gear and the second differential gear; There is a gap between the first differential gear and the second differential gear, the height of the first planetary gear is lower than the lower surface of the second differential gear, and the height of the second differential gear is lower than the upper surface of the first planetary gear and higher than the upper surface of the first differential gear.

4. The strength training apparatus according to claim 3, characterized in that: The differential also includes: A differential shaft, which is rotatably connected to the first differential gear and the second differential gear, the bottom of the differential shaft is fixedly connected to the bottom surface of the frame, and the top of the second output shaft is rotatably connected to the frame; The differential housing comprises: A lower housing, wherein a first bearing is disposed at the center of the lower housing; the first bearing is sleeved on the first output shaft and can rotatably connect the first output shaft and the lower housing; An upper housing, wherein a second bearing is disposed in the center of the upper housing; the second bearing is sleeved on the second output shaft and can rotatably connect the second output shaft and the upper housing; The differential shaft is rotatably connected to the second differential gear, the first differential gear and the first output shaft respectively through a third bearing, a fourth bearing and a fifth bearing from top to bottom.

5. The strength training apparatus according to claim 1, characterized in that: The lower wire take-up box and the upper wire take-up box are respectively arranged at the lower end and the upper end of the differential, the lower wire take-up box is sleeved on the first output shaft and fixedly connected to the first output shaft, and the upper wire take-up box is sleeved on the second output shaft and fixedly connected to the second output shaft.

6. The strength training apparatus according to claim 1, characterized in that: The speed change device, the differential and the wire take-up device are all located in the center of the frame, and the strength training device also includes pedal parts arranged on the left and right sides of the frame.

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