Differential with split function

Abstract

The present invention provides a differential with a separation function, comprising a housing (H) and a plurality of planetary shafts (10) mounted on the housing (H), wherein each planetary shaft (10) is provided with a planetary gear (40), wherein the planetary gear (40) can reciprocate in the radial direction of the housing (H), and the planetary gear (40) can mesh with the axle gears (60) of the differential to achieve power transmission, and the planetary gears (40) can move away from each other in the radial direction, thereby separating the planetary gears (40) from the axle gears (60) to achieve power interruption. The differential according to the present invention has a simple structure and can spontaneously achieve power interruption and transmission according to the speed during rotation.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and more particularly to a differential with a separation function of a vehicle. Background Art

[0002] When the vehicle switches between different operating states, the transmission system needs to be temporarily interrupted, or the transmission components in the transmission system need to be temporarily separated (hereinafter referred to as transmission system separation).

[0003] Taking electric vehicles as an example, for example, a two-speed eAxle drive system requires the transmission system to be disengaged during the gear shifting process; for another example, an eAxle drive system using a single-speed gearbox also requires the transmission system to be disengaged during the process of switching from four-wheel drive mode to two-wheel drive mode.

[0004] Figure 1 A possible transmission system separation device for an electric vehicle is shown, which includes a motor E (for example, a brushless DC motor), a lead screw S1, a nut S2, a guide post S3, and a shift fork F.

[0005] The rotation of motor E is transmitted to screw S1 via a pair of bevel gears. Screw S1 is fitted with a nut S2, which is constrained by a guide post S3 and cannot rotate about its own axis. Nut S2 reciprocates only along the axial direction of screw S1 during its rotation relative to screw S1. A pin P is positioned in the middle of the shift fork F, allowing it to rotate about it. One end of the fork F is connected to nut S2, and the other end is equipped with a shift finger F0, which engages and disengages the transmission components of the vehicle's drivetrain.

[0006] The reciprocating motion of nut S2 drives shift fork F to rotate around pin P like a lever, causing shift finger F0 to reciprocate, thereby engaging or disengaging transmission components such as synchronizers or dog clutches. The entire power transmission path is: motor E, bevel gear pair, leadscrew S1, nut S2, shift fork F, and then to shift finger F0.

[0007] The above solution has the following shortcomings:

[0008] (i) Due to the limited space inside the vehicle, the transmission ratio of the bevel gear pair is usually small. To ensure sufficient torque, a larger motor E is required, which increases the cost.

[0009] (ii) The shift fork assembly consisting of the shift fork F, the shift finger F0 and the pin P has a complex structure, high cost and low reliability.

[0010] (iii) The structures of the screw S1, nut S2 and bevel gear are complex and the manufacturing cost is high.

[0011] (iv) The entire device is large in size and difficult to arrange. Summary of the Invention

[0012] The object of the present invention is to overcome or at least alleviate the above-mentioned deficiencies in the prior art and to provide a differential with a separation function.

[0013] The present invention provides a differential with a separation function, characterized in that the differential comprises a housing and a plurality of planetary shafts mounted on the housing, each of the planetary shafts being provided with a planetary gear, and the planetary gear being capable of reciprocating in the radial direction of the housing.

[0014] The planetary gears can mesh with the side gears of the differential to achieve power transmission, and

[0015] The planetary gears can move away from each other in the radial direction, so that the planetary gears are separated from the side gears, thereby achieving power interruption.

[0016] In at least one embodiment, when the rotational speed of the housing is less than a critical value, the planetary gears remain in meshing engagement with the side gears.

[0017] When the rotation speed of the housing is equal to or greater than the critical value, the plurality of planetary gears can move away from each other in the radial direction and be separated from the side gears under the influence of centrifugal force.

[0018] In at least one embodiment, in the axial direction of the planetary shaft, each of the planetary gears is further connected to a sliding member in a relatively non-movable manner, and the sliding member can reciprocate along the axial direction.

[0019] In at least one embodiment, the differential further includes an elastic member configured to generate a force in an axial direction of the planetary shaft to move the plurality of planetary gears closer to each other.

[0020] In at least one embodiment, the differential further includes a plurality of counterweights, and in the axial direction of the planetary shaft, each of the planetary gears is connected to at least one of the counterweights in a relatively non-movable manner.

[0021] In at least one embodiment, when the planet gears are engaged with the side gears, the plurality of planet shafts abut against each other.

[0022] In at least one embodiment, the differential further includes an electromagnet capable of generating a magnetic field when energized to move the planetary gears away from each other in the radial direction.

[0023] In at least one embodiment, the electromagnet is disposed axially outside at least one of the planet shafts.

[0024] In at least one embodiment, the number of the electromagnet is one.

[0025] In at least one embodiment, at least the end of the planetary shaft on which the electromagnet acts, which is close to the electromagnet, is magnetized.

[0026] The differential according to the present invention has a simple structure and can spontaneously realize power interruption and transmission according to the speed during the rotation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a possible drive system disconnect device.

[0028] Figure 2 is a schematic diagram of a differential according to a first embodiment of the present invention.

[0029] Figure 3 1 is a schematic diagram showing a partial structure of a differential according to a second embodiment of the present invention.

[0030] Description of reference numerals:

[0031] E motor; S1 lead screw; S2 nut; S3 guide post; F shift fork; F0 shift finger; P pin;

[0032] 10 planetary shaft; 20 sliding part; 30 counterweight; 40 planetary gear; 50 output half shaft; 60 half shaft gear; 70 elastic part; 80 electromagnet; H differential housing. DETAILED DESCRIPTION

[0033] The following describes exemplary embodiments of the present invention with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present invention, and are not intended to exhaust all possible embodiments of the present invention, nor to limit the scope of the present invention.

[0034] (First embodiment)

[0035] First refer to Figure 2 , a differential with a separation function according to a first embodiment of the present invention is introduced.

[0036] The differential includes a housing H, two planetary shafts 10 , two sliding members 20 , two sets of counterweights 30 , two planetary gears 40 , two output half shafts 50 , two half shaft gears 60 and two elastic members 70 .

[0037] Compared with a conventional differential, the differential according to the present invention provides the planetary shafts on which the planetary gears 40 are mounted as two independent planetary shafts 10 that can move relatively.

[0038] Specifically, two planetary shafts 10 are coaxially disposed, and two output half shafts 50 are coaxially disposed, with the planetary shafts 10 and the output half shafts 50 disposed perpendicularly. A planetary gear 40 is sleeved on each planetary shaft 10 and is immovable relative to the planetary shaft 10 in the axial direction of the planetary shaft 10. A side gear 60 is connected to one output half shaft 50 in a torsionally fixed manner (restricted from relative rotation).

[0039] The two planetary shafts 10 can contact each other at opposite ends and can separate and move away from each other along the axial direction of the planetary shafts 10. When the two planetary shafts 10 are in contact, the planetary gears 40 mesh with the side gears 60, and the two output side shafts 50 operate normally to transmit power. When the two planetary shafts 10 separate and move away from each other, the planetary gears 40 and the side gears 60 are disengaged, and the power to the two output side shafts 50 is cut off.

[0040] Each planet shaft 10 is connected to a sliding member 20 in an axial direction of the planet shaft 10 so as to be non-movable relative to each other. For example, the planet shaft 10 and the sliding member 20 are fixed by pins, snap rings, etc.

[0041] In the axial direction of the planetary shaft 10 , the two sliders 20 are located on opposite sides of the two planetary gears 40 . In other words, in the radial direction of the housing H, the two sliders 20 are located outside the two planetary gears 40 .

[0042] Each sliding member 20 is provided with a set of counterweights 30 , and the counterweights 30 are evenly distributed on the sliding member 20 so that the entirety formed by the sliding member 20 and the counterweights 30 has a relatively large mass.

[0043] The sliding member 20 can reciprocate in the axial direction of the planetary shaft 10 relative to the housing H. For example, the inner cavity of the housing H is provided with a guide structure (such as a groove, not shown) extending along the axial direction of the planetary shaft 10 to limit the position of the sliding member 20 in the housing.

[0044] In summary, the connected planetary shaft 10, sliding member 20, counterweight 30 and planetary gear 40 form a movable unit that can reciprocate along the axial direction of the planetary shaft 10. The two movable units of the differential can move closer to or farther away from each other.

[0045] Each movable unit is connected to an elastic member 70, such as a compression spring. The elastic member 70 is positioned on the opposite side of the two movable units. More specifically, in the radial direction of the housing H, the elastic member 70 is located outside the slider 20. When the planetary shafts 10 of the two movable units abut each other, the elastic member 70 is compressed and applies a force to one movable unit along the axial direction of the planetary shaft 10, directed toward the other movable unit. For example, the elastic member 70 presses against the end of one planetary shaft 10 facing away from the other. It should be understood that this is merely an illustration of the direction of the force exerted by the elastic member 70, and does not specifically define the position of the elastic member 70. For example, the elastic member 70 can also be positioned around the planetary shaft 10, particularly if the elastic member 70 is a coil spring. Alternatively, the elastic member 70 can be positioned radially outside the slider 20, between the slider 20 and the housing H. One or more elastic members can be provided for each slider 20.

[0046] During the process of the housing H rotating around the two output half-shafts 50 , the movable unit (mainly the counterweight 30 ) is subjected to a large centrifugal force, and the direction of the centrifugal force is in the direction of separating the two movable units from each other.

[0047] When the rotation speed of the shell is less than or equal to the critical value (for example, 800 rpm), the centrifugal force exerted on the movable unit is less than or equal to the elastic force applied to the movable unit by the elastic member 70. At this time, the two movable units abut against each other, the two planetary shafts 10 are not separated, and the two output half shafts 50 can output power normally.

[0048] When the rotation speed of the housing is greater than the critical value, the centrifugal force on the movable unit is greater than the elastic force applied to the movable unit by the elastic member 70. At this time, the two movable units move away from each other, the two planetary shafts 10 are separated, and the power of the two output half shafts 50 is cut off.

[0049] In summary, in this embodiment, the differential acts as a node in the vehicle's transmission system, and can automatically trigger a power cut-off action according to the rotational speed of the housing H without requiring an additional transmission separation mechanism.

[0050] (Second embodiment)

[0051] Reference Figure 3 The second embodiment is a modification of the first embodiment, and the same reference numerals are used for the same or similar parts as those of the first embodiment, and detailed description thereof will be omitted.

[0052] Figure 3 The two planetary shafts 10 and the sliding members 20 and the counterweights 30 connected thereto are schematically highlighted, while other components of the differential are omitted.

[0053] In this embodiment, the differential further includes an electromagnet 80 , which is disposed near an end of one of the planetary shafts 10 axially away from the other planetary shaft 10 . In other words, the electromagnet 80 is disposed radially outside the housing H.

[0054] When electromagnet 80 is energized, the magnetic field it generates exerts an attractive force (magnetic force) on the planetary shafts 10 adjacent to electromagnet 80. The magnetic force on the planetary shafts 10 is in the same direction as the centrifugal force, and both the magnetic force and the centrifugal force can help the two planetary shafts 10 separate and move away from each other. In other words, the magnetic force is an auxiliary force that helps the planetary shafts 10 separate.

[0055] It should be understood that when the planetary gears 40 are meshed with the side gears 60, the meshing force makes it difficult for the planetary gears 40 and side gears 60 to separate. In this case, when the planetary shaft 10 on one side is attracted by the magnetic force, causing the planetary gears 40 and side gears 60 on that side to separate, the planetary gears 40 and side gears 60 on the other side can be easily separated. Therefore, to save cost and space, the electromagnet 80 can be provided on only one side.

[0056] The effect of magnetic force is particularly pronounced when the differential housing H rotates at a low speed. In this state, the centrifugal force acting on the movable unit including the planetary shafts 10 is relatively low, making it difficult for the two planetary shafts 10 to separate. At this point, energizing the electromagnet 80 generates a magnetic field that attracts the planetary shafts 10, thereby facilitating their separation. Furthermore, if the two planetary shafts 10 need to be repositioned to enable the differential's output axles to deliver power, this can be achieved more quickly by de-energizing the electromagnet 80.

[0057] Preferably, at least a portion of the planetary shaft 10 located at an end portion (an end close to the electromagnet 80 ) adjacent to the electromagnet 80 is magnetized.

[0058] Preferably, the contact surface of the two planetary shafts 10 is set to an uneven surface, and one of the ends of the two planetary shafts for abutting each other has a convex portion and the other has a concave portion, thereby ensuring that the abutting state of the two planetary shafts 10 is more stable.

[0059] The present invention has at least one of the following advantages:

[0060] (i) The differential according to the present invention has a separation function, and the separation device has a simple structure, low cost, few parts, and high reliability.

[0061] (ii) The separation device is integrated into the differential, which facilitates modular design.

[0062] (iii) The separating device including the electromagnet, the slide and the counterweight is easy to manufacture.

[0063] (iv) Since the release device is integrated into the differential, changes to the basic transmission components of the differential are relatively minor, and there is no need to set up other transmission devices outside the differential. It is easy to arrange in the vehicle and has a compact design.

[0064] Of course, the present invention is not limited to the above embodiments. Those skilled in the art can make various modifications to the above embodiments under the guidance of the present invention without departing from the scope of the present invention. For example:

[0065] (i) When the planetary gears 40 and the side gears 60 are meshed, the two planetary shafts 10 are closest to each other. However, these two planetary shafts 10 do not necessarily abut each other. For example, an intermediate abutment member can be interposed between the two planetary shafts 10. This intermediate abutment member can act as a buffer when the two planetary shafts 10 approach each other. Furthermore, buffer components or cushioning materials can be provided at the opposing ends of the two planetary shafts 10.

[0066] (ii) The elastic member 70 may not be disposed on opposite sides of the two sliding members 20. For example, the two elastic members 70 may be disposed between the two sliding members 20, with the elastic member 70 applying a pulling force (a force that pulls the two movable units closer together) to the movable units. (iii) Although the electromagnet 80 is disposed on the outside of only one planetary shaft 10 in the second embodiment, electromagnets may be disposed on the outside of both planetary shafts 10 if cost and space permit.

[0067] (iv) Although in the above two embodiments, the differential has only two planetary gears 40 and two planetary shafts 10, and each planetary gear 40 is arranged on one planetary shaft 10, in other possible embodiments, the differential may also have more than two planetary gears and planetary shafts, and each planetary gear is arranged on one planetary shaft.

[0068] (v) The sliding member 20 , the counterweight 30 and the elastic member 70 may also be connected to the planetary gear 40 not through the planetary shaft 10 , but may act on the planetary gear 40 directly or through other connecting members.

[0069] (vi) If the counterweight 30 is convenient to fix and / or the reciprocating motion of the planetary gear 40 is sufficiently guided, the sliding member 20 may be omitted. For example, the counterweight 30 may be directly fixed to the planetary gear 40 or the planetary shaft 10. For example, the housing H may have a guide groove for guiding the reciprocating motion of the planetary shaft 10.

Claims

1. A differential with a separation function, characterized in that: The differential comprises a housing (H) and a plurality of planetary shafts (10) mounted on the housing (H), each of the planetary shafts (10) being sleeved with a planetary gear (40), and the planetary gear (40) being capable of reciprocating in the radial direction of the housing (H). The planetary gear (40) can mesh with the side gear (60) of the differential to achieve power transmission, and The planetary gears (40) can move away from each other in the radial direction, thereby separating the planetary gears (40) from the side gears (60) to achieve power interruption.

2. The differential according to claim 1, characterized in that When the rotation speed of the housing (H) is less than a critical value, the planetary gear (40) and the side gear (60) remain in meshing engagement. When the rotation speed of the housing (H) is equal to or greater than the critical value, the plurality of planetary gears (40) can move away from each other in the radial direction and separate from the side gears (60) under the influence of centrifugal force.

3. The differential according to claim 1, characterized in that In the axial direction of the planetary shaft (10), each planetary gear (40) is also connected to a sliding member (20) in a relatively immovable manner, and the sliding member (20) can reciprocate along the axial direction.

4. The differential according to claim 1, characterized in that The differential further includes an elastic member (70) that generates a force in the axial direction of the planetary shaft (10) to move the plurality of planetary gears (40) closer to each other.

5. The differential according to claim 1, wherein: The differential further comprises a plurality of counterweights (30), and in the axial direction of the planetary shaft (10), each of the planetary gears (40) is connected to at least one of the counterweights (30) in a manner that they cannot move relative to each other.

6. The differential according to claim 1, characterized in that When the planetary gear (40) is meshed with the side gear (60), the plurality of planetary shafts (10) abut against each other.

7. The differential according to any one of claims 1 to 6, characterized in that: The differential further includes an electromagnet (80) capable of generating a magnetic field when energized to move the planetary gears (40) away from each other in the radial direction.

8. The differential according to claim 7, characterized in that The electromagnet (80) is arranged on the axially outer side of at least one of the planetary shafts (10).

9. The differential according to claim 8, characterized in that There is one electromagnet (80).

10. The differential according to claim 7, characterized in that At least the end of the planetary shaft (10) on which the electromagnet (80) acts, which is close to the electromagnet (80), is magnetized.

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