TW201839293A - Speed reducer - Google Patents

Abstract

A speed reducer is disclosed. When a shaft of a motor passes through a central front through hole, each axial hole, and a central rear through hole and then drives each driving assembly to rotate, due to the eccentric arrangement of a first section and a second section of a biasing rod, a first bearing and a second bearing are respectively operate with the inner edge of corresponding through holes of each wheel and further a plurality of rollers angularly spaced apart from one another and arranged at a peripheral of each wheel rotates to push the inner rollers of a sleeve-shaped rotation member so as to drive the sleeve-shaped rotation member to rotate and then achieve the effect of reducing speed.

Description

 Full roller reducer  

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a reduction gear transmission apparatus, and more particularly to a full roller speed reducer which is capable of achieving a reduction ratio by the rotation of an inner roller ring seat and the setting of at least two transmission groups.

In the traditional planetary transmission, the balance wheel transmission is widely used, and the planetary gear tooth profile adopts the parallel curve of the short outer swing line. The processing is complicated, the precision is difficult to control, the short-amplitude coefficient is large, and the root cutting and stress concentration are prone to occur. .

For a conventional conventional roller drive, please refer to US Pat. No. 5,431,605, which discloses a roller wave transmission device including an eccentric circular shock absorber connected to an input shaft, the device is on an eccentric circle and output. An intermediate transmission member connected to the shaft, and a pin wheel gear arranged on the fixed needle machine cymbal, wherein the intermediate transmission member is arranged around the roller cage hole by a plurality of freely rotatable circular rollers, the roller The outer edge of the cage is slightly smaller than the diameter of the root circle of the outer ring pin gear. The roller cage has an output shaft pin connected to the output shaft. The roller cage and the eccentric circular system have a double row structure, and the two eccentric circles are symmetric. Arranged 180 degrees.

Since the output shaft must be used, there are many parts, the structure is complicated, and the overall thickness is large, which cannot meet the market trend of thinning.

Moreover, the ratio of deceleration cannot be increased. If it is necessary to increase the deceleration, the volume must be increased or the number of the body must be increased, and the cost cannot be reduced.

The present invention provides a full-roller speed reducer which can achieve the effect of deceleration by using only the output shaft of the output roller, and can realize the deceleration by using only the rotation of the inner roller ring seat, and using at least two transmission groups.

Another object of the present invention is to provide a full roller reducer that saves parts, simplifies the structure, reduces the cost of the ground, and reduces the overall thickness to meet the current market trend of thinning.

The invention provides a full roller reducer, comprising a full roller reducer, comprising an inner roller ring seat, a rear gear seat, a front gear seat, a three transmission group, a third bearing and a fourth bearing. And a three-wheeled disc, wherein: the two sides of the inner roller ring seat are respectively connected to the rear gear seat and the front gear seat, and the rear gear seat covers the side of the inner roller ring seat, the front gear seat Plugging the other side of the inner roller ring seat, the rear gear seat and the front gear seat are detachably connected by a plurality of bolts, and the inner surface of the inner roller ring seat is provided with a plurality of axial and equiangular intervals a rear roller; the rear bracket 3 is provided with a rear central through hole, at least two pivot holes arranged at equal angular intervals, and a plurality of rear fixing holes disposed between the pivot holes; the front gear seat Having a front central perforation, at least two through holes arranged at equal angular intervals, and a plurality of front fixing holes disposed between the through holes, wherein the front central perforation is corresponding to the rear central perforation, each of the through holes Corresponding to each of the pivot holes, and the number of each of the through holes corresponds to each of the pivot holes The number of the front fixing holes is corresponding to each of the rear fixing holes, and the number of each of the front fixing holes corresponds to the number of each of the rear fixing holes; the third bearing system is disposed on the inner roller ring seat And the fourth bearing system is disposed between the inner roller ring seat and the front gear seat; each of the transmission groups is respectively disposed in each of the pivot holes and the corresponding one of the through holes And eccentrically interlacing with each of the inner rollers of the inner roller ring seat; and each of the disks is disposed side by side in the inner roller ring seat, and has an axial hole and an equal angular interval At least two through holes and a plurality of openings disposed between the through holes, wherein the shaft holes are disposed corresponding to the front central through hole and the rear central through hole, and each of the through holes of each of the rotating disks corresponds to Each of the through holes of the gear base and each of the pivot holes of the rear gear seat are disposed, and each of the opening holes is disposed corresponding to each of the front fixing holes of the front gear seat and the rear fixing holes of the rear gear seat, respectively The outer edge of the wheel disc is respectively provided with a plurality of axial outer rollers, which are respectively associated with the inner rollers of the inner roller ring seat Actuating, and each of the front fixing holes of the front seat is detachably connected by bolts through each of the corresponding openings of the wheel and then to the corresponding fixing holes of the corresponding rear seat; Each of the transmission sets includes a first bearing, a second bearing set, and an eccentric rod, the eccentric rod having a first rod segment and a second rod segment eccentrically connected to each other, the first bearing sleeve being disposed on The first rod segment is away from one end of the second rod segment, and the first bearing plug is disposed in the corresponding pivot hole, the second bearing group has a first outer roller bearing and a second outer roller a column bearing, and a third outer roller bearing, the first outer roller bearing is sleeved on the first rod segment and located between the first bearing and the second rod segment, the second outer roller bearing And the third outer roller bearing is sleeved side by side in the second rod segment, and the first outer roller bearing is inserted into the corresponding rear through hole of the wheel adjacent to the rear seat The second outer roller bearing and the third outer roller bearing are respectively inserted in the corresponding front through holes of the other two disks.

In some embodiments, when a spindle of a motor is inserted through the front central perforation, each of the shaft holes to the rear central perforation and drives the rotation with each of the transmission sets, The eccentric arrangement of the first rod segment and the second rod segment of the eccentric rod in the group respectively actuate the inner edge of the through hole of each of the roulettes through the first bearing and the second bearing group, respectively And a plurality of outer rollers disposed at equal angular intervals of the outer circumference of each of the discs advance the inner rollers of the inner roller ring seat to drive the rotation of the inner roller ring seat, thereby achieving deceleration efficacy.

In addition, the present invention further provides a full roller reducer, comprising a full roller reducer, comprising an inner roller ring seat, a rear gear seat, a front gear seat, a three transmission group, a third bearing, a first a four-bearing and a three-wheel disc, wherein: the two sides of the inner roller ring seat are respectively connected to the rear seat and the front seat, and the rear seat covers the side of the inner roller ring seat, the front gear The seat is plugged into the other side of the inner roller ring seat, and the rear seat and the front seat are detachably connected by a plurality of bolts, and the inner surface of the inner roller ring seat is provided with a plurality of axial directions and the like The inner roller is disposed at an angular interval; the rear retainer 3 is provided with a rear central through hole, at least two pivot holes disposed at equal angular intervals, and a plurality of rear fixing holes disposed between the pivot holes; the front gear The seat is provided with a front central perforation, at least two through holes arranged at equal angular intervals, and a plurality of front fixing holes disposed between the through holes, wherein the front central perforation is corresponding to the rear central perforation, each of which is The hole system is disposed corresponding to each of the pivot holes, and the number of each of the through holes is corresponding to each The number of the pivot holes, each of the front fixing holes is corresponding to each of the rear fixing holes, and the number of each of the front fixing holes corresponds to the number of the rear fixing holes; the third bearing is disposed in the inner roller Between the column ring seat and the rear block, the fourth bearing system is disposed between the inner roller ring seat and the front gear seat; each of the transmission groups is respectively disposed in each of the pivot holes and corresponding Each of the through holes is eccentrically interleaved with each of the inner rollers of the inner roller ring seat; and each of the disks is disposed side by side in the inner roller ring seat, and has a shaft hole, etc. At least two through holes disposed at an angular interval and a plurality of openings disposed between the through holes, wherein the shaft holes are disposed corresponding to the front central through hole and the rear central through hole, and each of the through holes of each of the rotating disks Corresponding to each of the through holes of the front seat and the pivot holes of the rear seat, each of the openings corresponds to each of the front fixing holes of the front seat and the rear fixing holes of the rear seat Arranging, the outer edge of each of the roulettes directly interacts with each of the inner rollers of the inner roller ring seat, and the front seat Each of the front fixing holes is detachably connected by bolts through the respective openings of the respective rotating disks and the corresponding rear fixing holes of the corresponding rear seats; wherein each of the transmission groups includes a a first bearing, a second bearing set, and an eccentric rod, the eccentric rod having a first rod segment and a second rod segment eccentrically connected to each other, the first bearing sleeve being disposed on the first rod segment away from the first portion One end of the two rod segments, and the first bearing plug is disposed in the corresponding pivot hole, the second bearing group has a first outer roller bearing, a second outer roller bearing, and a third outer a roller bearing, the first outer roller bearing is sleeved on the first rod segment, and is located between the first bearing and the second rod segment, the second outer roller bearing and the third outer roller bearing The second outer rod bearing is sleeved side by side, and the first outer roller bearing is inserted into the corresponding rear through hole of the rotating disc adjacent to the rear seat, the second outer roller bearing And the third outer roller bearing is respectively inserted in the corresponding front through hole of the other two wheel discs.

1‧‧‧Full roller reducer

20‧‧‧ bolt

2‧‧‧Inner roller ring seat

21‧‧‧Inside rollers

3‧‧‧ rear seat

31‧‧‧After central perforation

32‧‧‧Pivot hole

33‧‧‧ rear fixing hole

4‧‧‧ front stall

41‧‧‧ front central perforation

42‧‧‧through hole

43‧‧‧ front fixing hole

5‧‧‧ Transmission Group

51‧‧‧First bearing

52‧‧‧Second bearing set

521‧‧‧First outer roller bearing

522‧‧‧Second outer roller bearing

523‧‧‧ Third outer roller bearing

53‧‧‧eccentric rod

531‧‧‧first pole

532‧‧‧Second section

6‧‧‧ Third bearing

7‧‧‧fourth bearing

8‧‧‧ Spindle

A‧‧‧Rear Roulette

A1‧‧‧ rear axle hole

A2‧‧‧After through hole

Opening after A3‧‧

A4‧‧‧After the outer roller

B‧‧‧ Front Roulette

B1‧‧‧ front axle hole

B2‧‧‧ front through hole

B3‧‧‧ front opening

B4‧‧‧Pre-external roller

Fig. 1 is a rear perspective view showing the full roller reducer of the present invention.

Fig. 2 is a front perspective view showing the full roller reducer of the present invention.

Fig. 3 is a schematic exploded view showing the full roller reducer of the present invention.

Fig. 4 is a cross-sectional view showing the full roller reducer of the present invention.

Fig. 5 is a rear plan view showing the full roller reducer of the present invention.

Fig. 6 is a view showing the operation of the wheel in the full roller reducer of the present invention.

Fig. 7 is an exploded perspective view showing the transmission group in the full roller reducer of the present invention.

Fig. 8 is an exploded perspective view showing another embodiment of the full roller reducer of the present invention.

Figure 9 is a cross-sectional view showing another embodiment of the full roller reducer of the present invention.

Fig. 10 is a view showing the operation of the wheel in the other embodiment of the full roller reducer of the present invention.

Please refer to Fig. 1 to Fig. 7 at the same time. Fig. 1 is a perspective view showing the rear view of the full roller reducer of the present invention, and Fig. 2 is a front perspective view showing the full roller reducer of the present invention. The schematic diagram of the decomposition of the full roller reducer is created, the fourth figure shows a schematic cross-sectional view of the full roller reducer of the creation, the fifth figure shows the rear view plane of the full roller reducer of the creation, and the sixth figure shows the whole creation of the roller. Schematic diagram of the operation of the wheel in the roller reducer, Fig. 7 shows the exploded view of the transmission set in the full roller reducer of the present invention.

The full roller reducer 1 of the present invention comprises an inner roller ring seat 2, a rear gear base 3, a front gear base 4, at least two transmission groups 5, a third bearing 6, a fourth bearing 7, and a three-wheel disc This creation is described by taking three transmission groups 5 as an example, but the number thereof may be at least two, or more than three, and thus is not limited thereto.

The two sides of the inner roller ring seat 2 are respectively connected with the rear block 3 and the front block 4, and the rear block 3 can be sleeved on one side of the inner roller ring seat 2, and the front block 4 can be plugged. The other side of the roller ring seat 2; the rear seat 3 and the front seat 4 are detachably connected by a plurality of bolts 20, and the inner surface of the inner roller ring seat 2 is provided with a plurality of axial and equiangular intervals. Inner roller 21.

The rear seat 3 can be sleeved on one side of the inner roller ring seat 2, and the rear seat 3 is provided with a rear central through hole 31, at least two pivot holes 32 disposed at equal angular intervals, and disposed at each pivotal connection. A plurality of rear fixing holes 33 between the holes 32, wherein the number of the pivot holes 32 is corresponding to the number of the transmission groups 5. Therefore, the pivot holes 32 of the embodiment are described by taking three examples.

The front bracket 4 is slidably disposed on the other side of the rear roller bracket 2, and the front bracket 4 is provided with a front central through hole 41 and at least two through holes 42 equally spaced. And a plurality of front fixing holes 43 disposed between the through holes 42. The number of the through holes 42 is corresponding to the number of the transmission groups 5. Therefore, the through holes 42 of the embodiment are illustrated by three examples. The central through hole 41 is disposed corresponding to the rear central through hole 31, and each of the through holes 42 is disposed corresponding to each of the pivot holes 32, and the number of the through holes 42 corresponds to the number of the plurality of pivot holes 32, and each of the front fixing holes 43 is Corresponding to each of the rear fixing holes 33, the number of each of the front fixing holes 43 corresponds to the number of the respective rear fixing holes 33.

The third bearing 6 is disposed between the inner roller ring seat 2 and the rear gear base 3, and the fourth bearing 7 is disposed between the inner roller ring seat 2 and the front gear base 4.

Each of the front wheel B and the rear wheel A has the same structure, and each front wheel B is disposed adjacent to the front stage 4 and has a front axle hole B1, at least two front through holes B2 disposed at equal angular intervals, and each front through hole. a plurality of front openings B3 between B2, the rear wheel A is disposed adjacent to the rear seat 3 and has a rear axle hole A1, at least two rear through holes A2 arranged at equal angular intervals, and a plurality of rear through holes A2 disposed between the rear through holes A2 The rear opening A3, wherein the number of the front through hole B2 and the rear through hole A2 is the number of the corresponding transmission group 5, so the through hole B2 and the rear through hole A2 in the present embodiment are described by taking three examples as an example. The shaft hole B1 and the rear shaft hole A1 are respectively disposed corresponding to the front central through hole 41 and the rear central through hole 31, and each of the front through hole B2 and each of the rear through hole A2 is provided corresponding to each of the through holes 42 and each of the level holes 32, each of which is disposed. The front opening B3 is disposed corresponding to each of the rear opening A3 and the rear fixing hole 33; and each front fixing hole 43 is via the corresponding front opening B3 and the corresponding rear opening A3. Further, the respective rear fixing holes 33 are detachably connected by bolts 20.

The outer edges of the front wheel B and the rear wheel A are respectively provided with a plurality of axial front outer rollers B4 and a plurality of axial rear outer rollers A4, which are connected to the inner rollers 21 of the inner roller ring seat 2 Actuate.

The transmission groups 5 are respectively disposed in the respective pivot holes 32, the corresponding through holes 42 and the corresponding front through holes B2 and the rear through holes A2, and the structure of each transmission group 5 is as follows. 7 shows a first bearing 51, a second bearing set 52, and an eccentric rod 53 having a first rod segment 531 and a second rod segment 532 that are eccentrically connected to each other. The first bearing 51 is sleeved at an end of the first rod segment 531 away from the second rod segment 532, and the first bearing 51 is plugged in the corresponding pivot hole 32, and the second bearing group 52 has a a first outer roller bearing 521, a second outer roller bearing 522, and a third outer roller bearing 523, the first outer roller bearing 521 is sleeved on the first rod segment 531, and is located at the first Between the bearing 51 and the second rod segment 532, the second outer roller bearing 522 and the third outer roller bearing 523 are sleeved side by side in the second rod segment 523, the first outer roller The bearing 521 is inserted into the corresponding rear through hole A2 of the wheel A adjacent to the rear seat 3, and the second outer roller bearing 522 and the third outer roller bearing 523 are respectively plugged in B corresponding to the wheel within the front through-hole B2.

Therefore, when a spindle 8 (shown in FIG. 3) of a motor (not shown) is inserted through the front central through hole 41, the front axle hole B1, the rear axle hole A1 and the rear central through hole 321 and When the driving group 5 drives the rotation thereof, the eccentricity of the first rod segment 531 and the second rod segment 532 of the eccentric rod 53 in the transmission group 5 respectively passes through the first bearing 51 and the second bearing group 52 respectively to the rear wheel. After the disk B, the inner edge of the through hole B2 and the inner edge of the through hole A2 before the front wheel A are actuated, and then the rear outer rollers B4 disposed at the outer periphery of the rear wheel B at equal angular intervals and equiangular intervals are disposed at the front wheels. Each of the front outer rollers A4 on the outer periphery of the disk A advances the inner rollers 21 of the inner roller ring seat 2 to drive the rotation of the inner roller ring seat 2, thereby achieving the effect of deceleration.

Please refer to FIG. 8 to FIG. 10 again, wherein FIG. 8 is an exploded perspective view showing another embodiment of the full roller reducer of the present invention, and FIG. 9 is a cross-sectional view showing the other embodiment of the full roller reducer of the present invention. Referring to the schematic view, Fig. 10 is a view showing the operation of the wheel in the other embodiment of the full roller reducer of the present invention.

The structure of this embodiment is substantially the same as the foregoing embodiment, with the difference that the front wheel B does not use the front outer roller B4 and the rear wheel A does not use the rear outer roller A4, but the front wheel B and the rear wheel A The outer periphery directly interacts with the inner roller 21 of the inner roller ring seat 2, thereby effecting the movement of the wire (as shown in Fig. 10).

With the above structure, the full-roller reducer 1 of the present invention does not need to use the output shaft in response to the conventional technical structure, and only uses the rotation of the inner roller ring seat 2 to achieve the deceleration effect, and At least two transmission groups 5 are arranged, and the respective transmission groups 5 are not geared, but are respectively rotated by the first bearing 51 and the eccentricity of the eccentric rod 53 to not only reduce the friction consumption between each other. Moreover, the proportion of deceleration can be increased; thereby saving parts, simplifying the structure, and reducing the cost; furthermore, the overall thickness becomes smaller to conform to the current market trend of thinning.

While the foregoing is directed to the various embodiments of the present invention, further or further embodiments of the present invention may be devised without departing from the basic scope thereof, and the basic scope thereof is defined by the following claims. Although the present invention has been explained in connection with the preferred embodiments, it is not intended to limit the invention. It should be noted that many other similar embodiments can be constructed in accordance with the teachings of the present invention, which are within the scope of the present invention.

Claims (3)

 A full roller reducer comprises an inner roller ring seat, a rear gear seat, a front gear seat, a three gear set, a third bearing, a fourth bearing and a three wheel disc, wherein: the inner roller ring seat The two sides are respectively connected to the rear seat and the front seat, the rear seat is sleeved on one side of the inner roller ring seat, and the front seat is plugged with the other side of the inner roller ring seat The rear seat and the front seat are detachably connected by a plurality of bolts, and the inner surface of the inner roller ring seat is provided with a plurality of axial rollers arranged at equal angular intervals; the rear seat is worn a rear central perforation, at least two pivot holes arranged at equal angular intervals, and a plurality of rear fixing holes disposed between the pivot holes; the front gear seat is provided with a front central perforation and at least angular intervals a second through hole and a plurality of front fixing holes disposed between the through holes, wherein the front central through hole is disposed corresponding to the rear central through hole, and each of the through holes is disposed corresponding to each of the pivot holes, and each of the through holes is disposed The number of holes corresponds to the number of each of the pivot holes, and each of the front fixing holes corresponds to each of the holes a fixed hole arrangement, and the number of each of the front fixing holes corresponds to the number of each of the rear fixing holes; the third bearing is disposed between the inner roller ring seat and the rear block, the fourth bearing system is disposed Between the inner roller ring seat and the front gear seat; each of the transmission groups is respectively disposed in each of the pivot holes and the corresponding through holes, and is eccentrically coupled to the inner roller ring seat Each of the inner rollers is alternately actuated; and each of the rotating disks is disposed side by side in the inner roller ring seat, and has a shaft hole, at least two through holes arranged at equal angular intervals, and disposed between the through holes a plurality of openings, wherein the shaft holes are disposed corresponding to the front central perforation and the rear central perforation, and each of the through holes of each of the reels corresponds to each of the through holes of the front stage and the rear stage The pivot holes are disposed, and each of the openings is disposed corresponding to each of the front fixing holes of the front seat and the rear fixing holes of the rear seat, and the outer edges of each of the disks are respectively disposed with a plurality of axial directions. The outer roller is interlocked with each of the inner rollers of the inner roller ring seat, and each of the front fixing holes of the front gear seat Each of the corresponding opening holes of the corresponding wheel and the corresponding rear fixing holes of the rear seat are detachably connected by bolts; wherein each of the transmission sets includes a first bearing, a first a second bearing set, and an eccentric rod, the eccentric rod has a first rod segment and a second rod segment which are eccentrically connected to each other, and the first bearing sleeve is disposed at an end of the first rod segment away from the second rod segment, And the first bearing plug is disposed in the corresponding pivot hole, the second bearing set has a first outer roller bearing, a second outer roller bearing, and a third outer roller bearing, the first An outer roller bearing is sleeved on the first rod segment and located between the first bearing and the second rod segment, and the second outer roller bearing and the third outer roller bearing are sequentially arranged side by side Provided in the second rod segment, the first outer roller bearing is inserted into the corresponding through hole of the wheel disc adjacent to the rear seat, the second outer roller bearing and the third outer roller The bearings are respectively inserted in the corresponding through holes of the other two wheel discs.    The full roller reducer of claim 1, wherein a spindle of a motor is inserted through the front central through hole, each of the shaft holes to the rear central through hole and driven by each of the transmission groups When the rotation is performed, due to the eccentric arrangement of the first rod segment and the second rod segment of the eccentric rod in each of the transmission groups, respectively, the first bearing and the second bearing group are respectively passed through the first bearing and the second bearing group. The inner edge of the hole is actuated, and the inner rollers of the inner roller ring seat are advanced by a plurality of outer rollers disposed at equal angular intervals of the outer circumference of each of the disks to drive the inner roller ring seat. Rotate to achieve the effect of deceleration.    A full roller reducer comprises an inner roller ring seat, a rear gear seat, a front gear seat, a three gear set, a third bearing, a fourth bearing and a three wheel disc, wherein: the inner roller ring seat The two sides are respectively connected to the rear seat and the front seat, the rear seat is sleeved on one side of the inner roller ring seat, and the front seat is plugged with the other side of the inner roller ring seat The rear seat and the front seat are detachably connected by a plurality of bolts, and the inner surface of the inner roller ring seat is provided with a plurality of axial rollers arranged at equal angular intervals; the rear seat is worn a rear central perforation, at least two pivot holes arranged at equal angular intervals, and a plurality of rear fixing holes disposed between the pivot holes; the front gear seat is provided with a front central perforation and at least angular intervals a second through hole and a plurality of front fixing holes disposed between the through holes, wherein the front central through hole is disposed corresponding to the rear central through hole, and each of the through holes is disposed corresponding to each of the pivot holes, and each of the through holes is disposed The number of holes corresponds to the number of each of the pivot holes, and each of the front fixing holes corresponds to each of the holes a fixed hole arrangement, and the number of each of the front fixing holes corresponds to the number of each of the rear fixing holes; the third bearing is disposed between the inner roller ring seat and the rear block, the fourth bearing system is disposed Between the inner roller ring seat and the front gear seat; each of the transmission groups is respectively disposed in each of the pivot holes and the corresponding through holes, and is eccentrically coupled to the inner roller ring seat Each of the inner rollers is alternately actuated; and each of the rotating disks is disposed side by side in the inner roller ring seat, and has a shaft hole, at least two through holes arranged at equal angular intervals, and disposed between the through holes a plurality of openings, wherein the shaft holes are disposed corresponding to the front central perforation and the rear central perforation, and each of the through holes of each of the reels corresponds to each of the through holes of the front stage and the rear stage The pivot holes are disposed, and each of the openings is disposed corresponding to each of the front fixing holes of the front seat and the rear fixing holes of the rear seat, and an outer edge of each of the disks is directly connected to the inner roller ring Each of the inner rollers of the seat actuate with each other, and each of the front fixing holes of the front seat is via the corresponding each of the wheels And the rear fixing holes of the corresponding rear seat are detachably connected by bolts; wherein each of the transmission sets includes a first bearing, a second bearing set, and an eccentric rod, the eccentric rod a first rod segment and a second rod segment that are eccentrically connected to each other, the first bearing sleeve is disposed at an end of the first rod segment away from the second rod segment, and the first bearing plug is disposed at the corresponding one In the pivot hole, the second bearing set has a first outer roller bearing, a second outer roller bearing, and a third outer roller bearing, and the first outer roller bearing is sleeved on the first rod a second outer roller bearing and the third outer roller bearing are sequentially disposed side by side in the second rod segment, the first outer portion The roller bearing is inserted into the corresponding through hole of the wheel adjacent to the rear seat, and the second outer roller bearing and the third outer roller bearing are respectively inserted in the corresponding two second disks Inside the through hole.