Rotating shaft device and travel device

Abstract

A rotating shaft device and a travel device. The rotating shaft device comprises: a shaft body (110) having an external spline portion (111); a synchronizer (120) sleeved outside the shaft body (110), the synchronizer (120) being provided with an internal spline portion matching the external spline portion (111); two first bearings (130) sleeved outside the shaft body (110) at an interval, one of the two first bearings (130) being arranged adjacent to the synchronizer (120); a first cylindrical member (210) sleeved outside the shaft body (110), the first cylindrical member (210) being located between the two first bearings (130) and respectively abutting against inner rings of the two first bearings (130); and a first gear (140) sleeved outside the two first bearings (130). The rotating shaft device has a first state and a second state. In the first state, the synchronizer (120) is cooperatively connected to the first gear (140); and in the second state, the synchronizer (120) and the first gear (140) are arranged at an interval.

Description

Rotating shaft device and traveling equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 11, 2023, with application number 202311177605.3 and invention name “Rotating shaft device and traveling equipment”, the entire contents of which are incorporated by reference into the application. Technical Field

[0002] The present application relates to the technical field of rotating shafts, and in particular to a rotating shaft device and a traveling device. Background Art

[0003] Rotating shaft devices are commonly used in mechanical equipment. In related art, these devices consist of a shaft structure, a synchronizer structure, and two bearing structures. The synchronizer structure and the two bearing structures are sleeved onto the shaft structure. The synchronizer structure is splined to a predetermined position on the shaft structure. A spline boss is provided between the two bearing structures to define the positions of the two bearing structures. However, these bearing structures are susceptible to disassembly and damage. Technical issues

[0004] In view of this, embodiments of the present application hope to provide a rotating shaft device and a traveling device. Technical Solutions

[0005] The technical solution of this application is achieved as follows:

[0006] An embodiment of the present application provides a rotating shaft device, which includes:

[0007] A shaft body having an external spline portion;

[0008] A synchronizer is sleeved outside the shaft body; the synchronizer has an internal spline portion that cooperates with the external spline portion;

[0009] Two first bearings are spaced apart and sleeved outside the shaft body; one of the two first bearings is arranged adjacent to the synchronizer;

[0010] a first cylindrical member, sleeved outside the shaft body; the first cylindrical member is located between the two first bearings, and the first cylindrical member abuts against the inner rings of the two first bearings respectively;

[0011] A first gear is sleeved outside the two first bearings;

[0012] The rotating shaft device has a first state and a second state; in the first state, the synchronizer is in cooperative connection with the first gear; in the second state, the synchronizer is spaced apart from the first gear.

[0013] In some embodiments, the shaft device further comprises:

[0014] a second bearing sleeved outside the shaft body; the second bearing and the first bearing are located on opposite sides of the synchronizer;

[0015] A third bearing is sleeved outside the shaft body; the third bearing is spaced apart and arranged on a side of the second bearing away from the synchronizer;

[0016] a second gear, sleeved outside the second bearing and the third bearing;

[0017] In the second state, the synchronizer is in cooperative connection with the second gear.

[0018] In some embodiments, the shaft device further comprises:

[0019] a second cylindrical member, sleeved outside the shaft body; the second cylindrical member is located between the second bearing and the third bearing, and the second cylindrical member abuts against the inner ring of the second bearing and the inner ring of the third bearing respectively;

[0020] Wherein, the second bearing is a closed-end bearing, and the third bearing is a closed-end bearing.

[0021] In some embodiments, the shaft body has a first boss, the second bearing and the third bearing are located on opposite sides of the first boss, and the inner ring of the second bearing and the inner ring of the third bearing are respectively in contact with the first boss;

[0022] Wherein, the second bearing is an open bearing, and the third bearing is a closed bearing.

[0023] In some embodiments, the shaft body has a second boss, the synchronizer and the second bearing are located on opposite sides of the second boss, and the gear hub of the synchronizer and the inner ring of the second bearing are respectively in contact with the second boss.

[0024] In some embodiments, the shaft comprises:

[0025] The first shaft segment is arranged adjacent to the second boss; the first shaft segment has the external spline portion,

[0026] a second shaft segment located on a side of the first shaft segment away from the second boss; a diameter of the second shaft segment being smaller than a diameter of the first shaft segment;

[0027] The two first bearings and the first cylindrical member are sleeved on the second shaft segment. The inner ring of one of the two first bearings abuts against a step of the first shaft segment that protrudes from the second shaft segment in the circumferential direction.

[0028] In some embodiments, the shaft further comprises:

[0029] a third shaft segment disposed adjacent to the second boss; the third shaft segment and the first shaft segment being located on opposite sides of the second boss;

[0030] The second bearing and the third bearing are sleeved on the third shaft segment.

[0031] In some embodiments, the diameter of the third shaft segment is greater than the diameter of the second shaft segment.

[0032] In some embodiments, the shaft device further comprises:

[0033] a third cylindrical member, sleeved outside the shaft body; the third cylindrical member abuts against the inner ring of the first bearing away from the synchronizer among the two first bearings;

[0034] The fourth cylindrical member is sleeved outside the shaft body; the fourth cylindrical member is located on a side of the third bearing away from the second bearing and abuts against the inner ring of the third bearing.

[0035] In some embodiments, the first bearing, the second bearing and the third bearing are needle bearings; and / or,

[0036] The two first bearings are closed-end bearings.

[0037] The embodiment of the present application provides a traveling device, comprising a housing and the rotating shaft device of the embodiment of the present application,

[0038] The synchronizer, the two first bearings, the first cylindrical member, and the first gear are located in the housing. Beneficial effects

[0039] The rotating shaft device in the embodiment of the present application does not need to set a spline boss between the two first bearings. The first cylindrical member is located between the two first bearings. The first cylindrical member is used to limit the positions of the two first bearings. The two first bearings are not easily broken or damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG1 is a cross-sectional view of the structure of the rotating shaft device in an embodiment of the present application;

[0041] FIG2 is a schematic structural diagram of the shaft body in the rotating shaft device of FIG1 ;

[0042] FIG3 is a cross-sectional view of the structure of the rotating shaft device in an embodiment of the present application;

[0043] FIG4 is a schematic structural diagram of the shaft body in the rotating shaft device of FIG3 .

[0044] Figure numerals: 110, shaft body; 111, external spline portion; 112, first boss; 113, second boss; 114, first shaft section; 115, second shaft section; 116, third shaft section; 120, synchronizer; 121, gear hub; 130, first bearing; 140, first gear; 150, second gear; 160, second bearing; 170, third bearing; 210, first cylindrical member; 220, second cylindrical member; 230, third cylindrical member; 240, fourth cylindrical member. Modes for Carrying Out the Invention

[0045] The technical solution of the present application is further elaborated in detail below with reference to the accompanying drawings and specific embodiments.

[0046] In the description of the embodiments of this application, it should be noted that, unless otherwise specified and limited, the term "connection" should be understood in a broad sense. For example, it can be an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meaning of the above terms can be understood according to the specific circumstances.

[0047] It should be noted that the terms "first, second, and third" in the embodiments of the present application are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It is understood that the terms "first, second, and third" can be interchanged to represent a specific order or precedence where permitted. It should be understood that the objects distinguished by "first, second, and third" can be interchanged where appropriate, such that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0048] The following is a detailed description of the rotating shaft device described in the embodiment of the present application with reference to FIG. 1 to FIG. 4 .

[0049] As shown in Figure 1, the rotating shaft device includes a shaft body 110, a synchronizer 120, two first bearings 130, a first cylindrical member 210, and a first gear 140. The shaft body 110 has an external spline portion 111; the synchronizer 120 is sleeved outside the shaft body 110 and has an internal spline portion that cooperates with the external spline portion 111; the two first bearings 130 are sleeved outside the shaft body 110 at intervals; one of the two first bearings 130 is disposed adjacent to the synchronizer 120; the first cylindrical member 210 is sleeved outside the shaft body 110; the first cylindrical member 210 is located between the two first bearings 130 and abuts against the inner rings of the two first bearings 130 respectively; the first gear 140 is sleeved outside the two first bearings 130; the rotating shaft device has a first state and a second state. In the first state, the synchronizer 120 is engaged and connected with the first gear 140; in the second state, the synchronizer 120 and the first gear 140 are spaced apart.

[0050] In the related art, a rotating shaft device includes a shaft structure, a synchronization structure, and two bearing structures. The synchronization structure and the two bearing structures are mounted on the shaft structure. The synchronization structure is splined to the shaft structure's set position. A spline boss is provided between the two bearing structures. When the synchronization structure is installed on the rotating shaft structure, it must pass through the spline boss before being mounted on the shaft structure's set position. The spline boss is used to define the position of the two bearing structures. However, due to the incomplete end surface of the spline boss, there is a recessed area on the end surface of the spline boss, which makes the two bearing structures prone to falling apart and damage. Furthermore, to facilitate the synchronization structure's mounting on the shaft structure's set position, the boss provided between the two bearing structures requires spline processing, making the shaft structure relatively complex and difficult to manufacture. However, the rotating shaft device of the present application does not require a spline boss between the two first bearings 130. Instead, the first cylindrical member 210 is located between the two first bearings 130 and defines the position of the two first bearings 130. In this case, the two first bearings 130 are less likely to fall apart and damage. At the same time, since no spline bosses need to be machined, the shaft structure is relatively simple, greatly reducing the difficulty of machining. In addition, since the first cylindrical member 210 is sleeved outside the shaft body 110, the synchronizer 120 can be installed on the shaft body 110 first, and then the first cylindrical member 210 can be installed on the shaft body 110. The synchronizer 120 does not need to be considered when installing the spline bosses, which greatly reduces the difficulty of installing the rotating shaft device.

[0051] In an embodiment of the present application, the shaft 110 has an external spline portion 111, and the synchronizer 120 has an internal spline portion. By cooperating with the external spline portion 111 and the internal spline portion, the synchronizer 120 can be fixed in the rotational direction relative to the shaft 110, that is, the synchronizer 120 and the shaft 110 can rotate together.

[0052] The synchronizer 120 may include a gear hub 121 and a connecting portion. The gear hub 121 may have an internal spline portion. The connecting portion may be movable relative to the gear hub 121 and may be coupled to or spaced apart from the first gear 140 .

[0053] The specific structure of the synchronizer 120 is not limited, as long as the synchronizer 120 can be fixed to the shaft 110 and can be connected to or spaced apart from the first gear 140. When the synchronizer 120 is connected to the first gear 140, the first gear 140 can rotate with the synchronizer 120 and the shaft 110. When the synchronizer 120 is spaced apart from the first gear 140, the first gear 140 does not rotate with the synchronizer 120 and the shaft 110, that is, the first gear 140 is loosely mounted on the shaft 110.

[0054] In one embodiment, the synchronizer 120 may be a normal pressure synchronizer 120 , an inertia synchronizer 120 , or a self-energizing synchronizer 120 .

[0055] The gear hub 121 of the synchronizer 120 is fixed in an axial position relative to the shaft 110. The manner in which the gear hub 121 of the synchronizer 120 is fixed in an axial position relative to the shaft 110 is not limited. For example, the gear hub 121 of the synchronizer 120 may be fixed in an axial position by a step on the shaft 110 or by a structural member sleeved on the shaft 110.

[0056] In one embodiment, as shown in Figures 1 and 2, the shaft 110 has a second boss 113, one end of the gear hub 121 of the synchronizer 120 abuts against the second boss 113, and the other end of the gear hub 121 of the synchronizer 120 abuts against a structural member on the shaft 110. The structural member on the shaft 110 can be a shaft ring or a retaining ring.

[0057] In the embodiment of the present application, the type of the first bearing 130 is not limited. For example, the first bearing 130 can be a needle roller bearing. Of course, in other examples, the first bearing 130 can also be other types of bearings.

[0058] The two first bearings 130 may be open bearings or closed bearings. When the two first bearings 130 are closed bearings, the probability of failure of the first bearings 130 can be reduced.

[0059] The two first bearings 130 are sleeved on the shaft 110, with one end of the inner ring of the two first bearings 130 being defined by the first cylindrical member 210. The other end of the inner ring of the two first bearings 130 may be defined by any means. For example, the other end of the inner ring of the two first bearings 130 may be defined by a step on the shaft 110 or by a structural member sleeved on the shaft 110.

[0060] In one embodiment, the other end of the inner ring of the first bearing 130 of the two first bearings 130, which is closer to the synchronizer 120, abuts against the step on the shaft body 110, thereby being limited by the step on the shaft body 110; the other end of the inner ring of the first bearing 130 of the two first bearings 130, which is away from the synchronizer 120, abuts against the structural member sleeved on the shaft body 110, thereby being limited by the structural member sleeved on the shaft body 110; the structural member sleeved on the shaft body 110 can be a shaft ring or a retaining ring.

[0061] In one application, as shown in Figures 1 and 3, the rotating shaft device may further include a third cylindrical member 230, which is sleeved on the outside of the shaft body 110; the third cylindrical member 230 abuts against the inner ring of the first bearing 130 of the two first bearings 130 away from the synchronizer 120; so that the inner ring of the first bearing 130 of the two first bearings 130 away from the synchronizer 120 can be limited by the third cylindrical member 230.

[0062] The structure of the third cylindrical member 230 is not limited. For example, the third cylindrical member 230 can be a cylindrical gasket, a shaft ring, or a snap ring.

[0063] It should be noted that, in FIG. 1 and FIG. 3 , there is a gap between the third cylindrical member 230 and the first gear 140 , and the third cylindrical member 230 and the first gear 140 are not in contact with each other.

[0064] In the embodiment of the present application, the structure of the first cylindrical member 210 is not limited. For example, the first cylindrical member 210 can be a cylindrical gasket or a shaft ring.

[0065] In the embodiment of the present application, the first gear 140 is sleeved outside the two first bearings 130 so that the first gear 140 is supported by the two first bearings 130 and the first gear 140 is loosely sleeved on the shaft 110 through the two first bearings 130 .

[0066] The rotating shaft device has a first state and a second state; in the first state, the synchronizer 120 is connected with the first gear 140, and at this time, the synchronizer 120 can drive the first gear 140 to rotate together; in the second state, the synchronizer 120 and the first gear 140 are spaced apart, and at this time, the first gear 140 will not rotate with the synchronizer 120.

[0067] In the embodiment of the present application, the rotating shaft device may further include: a second bearing 160, a third bearing 170, and a second gear 150. The second bearing 160 is sleeved outside the shaft body 110; the second bearing 160 and the first bearing 130 are located on opposite sides of the synchronizer 120; the third bearing 170 is sleeved outside the shaft body 110; the third bearing 170 is spaced apart and disposed on the side of the second bearing 160 away from the synchronizer 120; the second gear 150 is sleeved outside the second bearing 160 and the third bearing 170; in the second state, the synchronizer 120 is mated and connected to the second gear 150, so that the second gear 150 rotates together with the synchronizer 120.

[0068] Of course, the rotating shaft device can also have a third state. In the third state, the synchronizer 120 is spaced apart from the first gear 140 and the second gear 150 , so that the first gear 140 and the second gear 150 do not rotate together with the synchronizer 120 .

[0069] In this embodiment, the basic parameters of the first gear 140 and the basic parameters of the second gear 150 can be the same or different. When the basic parameters of the first gear 140 and the basic parameters of the second gear 150 are different, the shaft device can output different transmission ratios through the first gear 140 and the second gear 150.

[0070] In this implementation, the type of the second bearing 160 is not limited. For example, the second bearing 160 can be a needle bearing. Of course, in other examples, the second bearing 160 can also be other types of bearings.

[0071] The second bearing 160 is sleeved on the shaft 110, and the method of defining the ends of the inner ring of the second bearing 160 is not limited. For example, the ends of the inner ring of the second bearing 160 can be defined by steps on the shaft 110, or by a structural member sleeved on the shaft 110.

[0072] In this implementation, the type of the third bearing 170 is not limited. For example, the third bearing 170 can be a needle bearing. Of course, in other examples, the third bearing 170 can also be other types of bearings.

[0073] The third bearing 170 is sleeved on the shaft 110, and the method of defining the ends of the inner ring of the third bearing 170 is not limited. For example, the ends of the inner ring of the third bearing 170 can be defined by steps on the shaft 110, or by a structural member sleeved on the shaft 110.

[0074] In this implementation, the shaft body 110 can have a second boss 113, and the synchronizer 120 and the second bearing 160 can be located on opposite sides of the second boss 113. The gear hub 121 of the synchronizer 120 and the inner ring of the second bearing 160 are respectively abutted against the second boss 113, so as to limit the gear hub 121 of the synchronizer 120 and the inner ring of the second bearing 160 respectively through the second boss 113.

[0075] In this embodiment, as shown in Figures 2 and 4, the shaft body 110 may include: a first shaft segment 114 and a second shaft segment 115. The first shaft segment 114 is disposed adjacent to the second boss 113; the first shaft segment 114 has an external spline portion 111, and the second shaft segment 115 is located on a side of the first shaft segment 114 away from the second boss 113; the diameter of the second shaft segment 115 is smaller than that of the first shaft segment 114; two first bearings 130 and a first cylindrical member 210 are sleeved on the second shaft segment 115.

[0076] The inner ring of one of the two first bearings 130 abuts against the step of the first shaft segment 114 that protrudes circumferentially from the second shaft segment 115, so that the inner ring of one of the two first bearings 130 is limited by the step formed by the first shaft segment 114 and the second shaft segment 115, thereby simplifying the structure of the rotating shaft device.

[0077] Of course, in other implementations, the inner ring of one of the two first bearings 130 may also be defined by a structural member sleeved on the shaft body 110 .

[0078] The shaft body 110 may further include: a third shaft segment 116 , which is arranged adjacent to the second boss 113 ; the third shaft segment 116 and the first shaft segment 114 are located on opposite sides of the second boss 113 ; and the second bearing 160 and the third bearing 170 are sleeved on the third shaft segment 116 .

[0079] 2 and 4 , the diameter of the third shaft segment 116 may be greater than the diameter of the second shaft segment 115 . Of course, the diameter of the third shaft segment 116 may also be less than or equal to the diameter of the second shaft segment 115 .

[0080] In one embodiment, as shown in Figures 1 and 2, the shaft body 110 has a first boss 112, and the second bearing 160 and the third bearing 170 are located on opposite sides of the first boss 112. The inner ring of the second bearing 160 and the inner ring of the third bearing 170 are respectively abutted against the first boss 112; so that the inner ring of the second bearing 160 and the inner ring of the third bearing 170 are respectively limited by the first boss 112.

[0081] In one embodiment, the other end of the inner ring of the second bearing 160 may be defined by a step on the shaft body 110 or by a structural member sleeved on the shaft body 110 .

[0082] In one embodiment, as shown in FIG. 1 , the gear hub 121 of the synchronizer 120 and the inner ring of the second bearing 160 may be respectively limited by the second boss 113 .

[0083] Here, the second bearing 160 is an open type bearing, so that the second bearing 160 can be installed between the second boss 113 and the first boss 112 .

[0084] In one embodiment, the other end of the inner ring of the third bearing 170 may be defined by a step on the shaft body 110 or by a structural member sleeved on the shaft body 110 .

[0085] In one embodiment, as shown in Figure 1, the rotating shaft device may further include: a fourth cylindrical member 240, which is sleeved outside the shaft body 110; the fourth cylindrical member 240 is located on the side of the third bearing 170 away from the second bearing 160, and abuts against the inner ring of the third bearing 170, so that the inner ring of the third bearing 170 is limited by the fourth cylindrical member 240.

[0086] Here, the structure of the fourth cylindrical member 240 is not limited. For example, the fourth cylindrical member 240 can be a cylindrical gasket, a shaft ring, or a snap ring.

[0087] It should be noted that, as shown in FIG. 1 and FIG. 3 , there is a gap between the fourth cylindrical member 240 and the second gear 150 , and the fourth cylindrical member 240 and the second gear 150 are not in contact with each other.

[0088] Here, the third bearing 170 can be an open bearing or a closed bearing. When the third bearing 170 is a closed bearing, the probability of the third bearing 170 failing can be reduced.

[0089] When the rotating shaft device includes the second cylindrical member 220 , the second cylindrical member 220 is sleeved on the third shaft segment 116 .

[0090] In one embodiment, as shown in Figures 3 and 4, the rotating shaft device may further include: a second cylindrical member 220, which is sleeved outside the shaft body 110; the second cylindrical member 220 is located between the second bearing 160 and the third bearing 170, and the second cylindrical member 220 is respectively in contact with the inner ring of the second bearing 160 and the inner ring of the third bearing 170; so that the inner ring of the second bearing 160 and the inner ring of the third bearing 170 are limited by the second cylindrical member 220.

[0091] In one embodiment, the other end of the inner ring of the second bearing 160 may be defined by a step on the shaft body 110 or by a structural member sleeved on the shaft body 110 .

[0092] In one embodiment, as shown in FIG. 3 , the gear hub 121 of the synchronizer 120 and the inner ring of the second bearing 160 are respectively limited by the second boss 113 .

[0093] Here, the second bearing 160 can be an open bearing or a closed bearing. When the second bearing 160 is a closed bearing, the probability of the second bearing 160 failing can be reduced.

[0094] In Example 2, the other end of the inner ring of the third bearing 170 can be defined by a step on the shaft body 110 or by a structural member sleeved on the shaft body 110 .

[0095] In one embodiment, as shown in FIG. 3 , the inner race of the third bearing 170 is defined by a fourth cylindrical member 240 .

[0096] Here, the third bearing 170 can be an open bearing or a closed bearing. When the third bearing 170 is a closed bearing, the probability of the third bearing 170 failing can be reduced.

[0097] When the rotating shaft device includes the first boss 112 , the first boss 112 is located on the third shaft segment 116 .

[0098] The embodiment of the present application also describes a traveling device, including a housing and a rotating shaft device of the embodiment of the present application, wherein the synchronizer 120 , two first bearings 130 , a first cylindrical member 210 and a first gear 140 are located in the housing.

[0099] Here, the housing may be a housing of a driving system of a traveling device, so as to realize multi-speed driving through the first gear 140 and the second gear 150 .

[0100] The shaft body 110 may be entirely located in the housing, or may be partially located in the housing.

[0101] The shaft body 110 may be rotatably provided via a bearing.

[0102] The structure of the traveling device is not limited. For example, the traveling device can be a car or a truck.

[0103] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A rotating shaft device, wherein: The rotating shaft device comprises: A shaft body having an external spline portion; A synchronizer is sleeved outside the shaft body; the synchronizer has an inner spline portion that matches the outer spline portion; Two first bearings are spaced apart and sleeved outside the shaft body; one of the two first bearings is disposed adjacent to the synchronizer; A first cylindrical member is sleeved outside the shaft body; the first cylindrical member is located between the two first bearings, and the first cylindrical member abuts against the inner rings of the two first bearings respectively; A first gear is sleeved outside the two first bearings; The rotating shaft device has a first state and a second state; in the first state, the synchronizer is connected with the first gear in cooperation; in the second state, the synchronizer is spaced apart from the first gear.

2. The rotating shaft device according to claim 1, wherein: The rotating shaft device also includes: A second bearing is sleeved outside the shaft body; the second bearing and the first bearing are located on opposite sides of the synchronizer; A third bearing is sleeved outside the shaft body; the third bearing is spaced apart and arranged on a side of the second bearing away from the synchronizer; A second gear, sleeved outside the second bearing and the third bearing; In the second state, the synchronizer is in cooperative connection with the second gear.

3. The rotating shaft device according to claim 2, wherein: The rotating shaft device also includes: A second cylindrical member is sleeved outside the shaft body; the second cylindrical member is located between the second bearing and the third bearing, and the second cylindrical member abuts against the inner ring of the second bearing and the inner ring of the third bearing respectively; Wherein, the second bearing is a closed-end bearing, and the third bearing is a closed-end bearing.

4. The rotating shaft device according to claim 2, wherein: The shaft body has a first boss, the second bearing and the third bearing are located on opposite sides of the first boss, and the inner ring of the second bearing and the inner ring of the third bearing are respectively in contact with the first boss; Wherein, the second bearing is an open bearing, and the third bearing is a closed bearing.

5. The rotating shaft device according to claim 2, wherein: The shaft body has a second boss, the synchronizer and the second bearing are located on opposite sides of the second boss, and the gear hub of the synchronizer and the inner ring of the second bearing are respectively in contact with the second boss.

6. The rotating shaft device according to claim 5, wherein: The shaft body comprises: A first shaft section is disposed adjacent to the second boss; the first shaft section has the external spline portion, a second shaft segment, located on a side of the first shaft segment away from the second boss; a diameter of the second shaft segment is smaller than a diameter of the first shaft segment; The two first bearings and the first cylindrical member are sleeved on the second shaft segment, and the inner ring of one of the two first bearings abuts against a step of the first shaft segment that protrudes from the second shaft segment in the circumferential direction.

7. The rotating shaft device according to claim 6, wherein: The shaft body also includes: a third shaft segment, disposed adjacent to the second boss; the third shaft segment and the first shaft segment are located on opposite sides of the second boss; The second bearing and the third bearing are sleeved on the third shaft segment.

8. The rotating shaft device according to claim 7, wherein: The diameter of the third shaft segment is greater than the diameter of the second shaft segment.

9. The rotating shaft device according to any one of claims 2 to 8, wherein: The rotating shaft device also includes: A third cylindrical member is sleeved outside the shaft body; the third cylindrical member abuts against the inner ring of the first bearing far away from the synchronizer among the two first bearings; The fourth cylindrical member is sleeved outside the shaft body; the fourth cylindrical member is located on a side of the third bearing away from the second bearing and abuts against the inner ring of the third bearing.

10. The rotating shaft device according to any one of claims 2 to 8, wherein: The first bearing, the second bearing and the third bearing are all needle bearings; and / or, The two first bearings are closed-end bearings.

11. A traveling device, wherein: The travel device comprises a housing and a rotating shaft device according to any one of claims 1 to 10, The synchronizer, the two first bearings, the first cylindrical member and the first gear are located in the housing.

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