differential

Abstract

The present invention relates to a differential, which includes a planetary gear and a planetary gear shaft, wherein the planetary gear is capable of rotating relative to the planetary gear shaft, and further includes a speed limiting mechanism arranged on the planetary gear, the speed limiting mechanism including an elastic element and a slider, when the rotational speed of the planetary gear is lower than a rotational speed threshold, the slider slides on the planetary gear shaft with a first contact point on a first surface under the action of both a first elastic force exerted by the elastic element and a first centrifugal force, and when the rotational speed of the planetary gear is greater than the rotational speed threshold, the slider slides on the planetary gear shaft with a second contact point on the first surface under the action of both a second elastic force of the elastic element and a second centrifugal force, wherein the second contact point is closer to the edge of the first surface of the slider than the first contact point, so that the friction force when the slider contacts the planetary gear shaft at the second contact point is greater than the friction force when the slider contacts the planetary gear shaft at the first contact point.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and in particular to a differential in a vehicle. Background Art

[0002] While a vehicle is in motion, the angular velocities of the left and right drive wheels often differ. In this situation, if the vehicle lacks a differential and both drive wheels are fixed to the same rigid axle, the drive wheels will inevitably experience rolling and slipping. This phenomenon can cause tire wear, power loss, and even render the vehicle unable to steer. Therefore, differentials are used in vehicles to achieve a speed difference between the left and right drive wheels when the vehicle is not traveling in a straight line, allowing the vehicle to operate normally.

[0003] However, the differential in the prior art has the problem of excessively high rotational speed, which causes the components of the differential to be exposed to excessively high ambient temperatures, thereby causing the components of the differential to be damaged by the high temperature, thereby shortening the service life of the differential. Summary of the Invention

[0004] The object of the present invention is to provide a differential with a longer service life.

[0005] The present invention provides a differential comprising planetary gears and a planetary gear shaft, wherein the planetary gears are rotatable relative to the planetary gear shaft.

[0006] The invention also includes a speed limiting mechanism provided on the planetary gear, wherein the speed limiting mechanism includes an elastic element and a slider. When the rotation speed of the planetary gear is lower than a rotation speed threshold, the slider slides on the planetary gear shaft at a first contact point on a first surface under the action of both a first elastic force and a first centrifugal force exerted by the elastic element. When the rotation speed of the planetary gear is greater than the rotation speed threshold, the slider slides on the planetary gear shaft at a second contact point on the first surface under the action of both a second elastic force and a second centrifugal force of the elastic element.

[0007] The second contact point is closer to the edge of the first surface of the slider than the first contact point, so that the friction force when the slider contacts the planetary gear shaft at the second contact point is greater than the friction force when the slider contacts the planetary gear shaft at the first contact point.

[0008] According to an embodiment of the present invention, a first groove and a second groove are provided on the planetary gear, and the first groove is used to accommodate the elastic element in a manner allowing the elastic element to freely expand and contract, and the second groove is used to accommodate the slider in a manner allowing the slider to freely swing.

[0009] According to an embodiment of the present invention, the first groove and the second groove are configured to communicate with each other, so that the elastic element directly applies elastic force to the slider.

[0010] According to an embodiment of the present invention, the first groove is configured to extend in a direction forming a certain angle with the radial direction of the planetary gear, and the elastic force of the elastic element has a component force in the radial direction so that the slider is pressed onto the planetary gear shaft.

[0011] According to an embodiment of the present invention, two speed limiting mechanisms are provided on the planetary gear, and the two speed limiting mechanisms are configured to be 180 degrees apart from each other.

[0012] According to an embodiment of the present invention, the elastic element of the speed limiting mechanism is configured as a coil spring.

[0013] According to an embodiment of the present invention, the slider is configured to have rounded corners.

[0014] According to an embodiment of the present invention, the first groove and the second groove are configured as through holes formed on the planetary gear.

[0015] According to an embodiment of the present invention, the two speed limiting mechanisms are constructed identically to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A differential according to an embodiment of the present invention is shown.

[0017] Figure 2 A speed limiting mechanism in a differential according to an embodiment of the present invention is shown.

[0018] Figure 3 A speed limiting mechanism in a differential according to an embodiment of the present invention is shown.

[0019] Figure 4 The speed limiting mechanism in the differential according to the embodiment of the present invention is shown in a first working condition.

[0020] Figure 5 The speed limiting mechanism of the differential according to the embodiment of the present invention is shown in the second working condition. DETAILED DESCRIPTION

[0021] The following detailed description and accompanying drawings are used to illustrate the principles of the present invention. The present invention is not limited to the preferred embodiments described. The scope of protection of the present invention is defined by the claims.

[0022] Figure 1 The differential according to the embodiment of the present invention is shown. Figure 1A differential according to an embodiment of the present invention will be described.

[0023] like Figure 1 As shown, the differential 10 includes two planetary gears 100, a left side gear 500, a right side gear 600, and a gear carrier 400. Power is transmitted to the gear carrier 400 in the differential 10 via the input shaft 20. The gear carrier 400 drives the two planetary gears 100 to rotate via the planetary gear shafts 200. The power is then transmitted to the left side gear 500 and the right side gear 600 via the planetary gears 100.

[0024] The differential according to the present invention also includes a speed limiting mechanism provided on the planetary gears. In the differential, the planetary gears are capable of rotating relative to the planetary gear shafts. This speed limiting mechanism is used to limit the relative rotational speed between the planetary gears and the planetary gear shafts, thereby limiting the rotational speed of the differential. The speed limiting mechanism in the differential according to an embodiment of the present invention is described in detail below.

[0025] Figure 2 A speed limiting mechanism in a differential according to an embodiment of the present invention is shown. Figure 3 The speed limiting mechanism in the differential according to the embodiment of the present invention is shown. Figure 2 and Figure 3 A speed limiting mechanism in a differential according to an embodiment of the present invention will be described.

[0026] like Figure 2 and Figure 3 As shown, in this embodiment, two first grooves 101 and two second grooves 102 are provided on the planetary gear 100, and a pair of the first groove 101 and the second groove 102 are provided Figure 2 On the upper part of the planetary gear 100, another pair of first grooves and second grooves are provided. Figure 2 In the lower part of the planetary gear 100, the two pairs of grooves are respectively used to arrange a speed limiting mechanism 300. Moreover, the two pairs of grooves are set to be identical to each other. It should be noted that the "identical" here mainly refers to the fact that one pair of grooves coincides with the other pair of grooves after rotating a certain angle around the central axis of the planetary gear 100. In addition, the two speed limiting mechanisms 300 are also set to be identical to each other. It should be noted that the term "identical" related to the speed limiting mechanism should be understood with reference to the term "identical" related to the groove above. Specifically, as Figure 2 As shown, the first groove 101 and the second groove 102 are configured to communicate with each other, and the first groove 101 and the second groove 102 are configured to be through holes formed on the planetary gear 100. In addition, based on the consideration of easily ensuring the overall structure of the planetary gear 100, the first groove 101 is configured to extend in a direction forming a certain angle with the radial direction of the planetary gear 100. Figure 2 and Figure 3In the embodiment shown, the two speed limiting mechanisms 300 are specifically configured to be 180 degrees apart from each other. The following describes in detail only the one located at the top of the two speed limiting mechanisms 300. Figure 2 The speed limiting mechanism 300 is located at the upper portion of the planetary gear 100. Figure 2 The speed limiting mechanism 300 on the upper portion of the middle planetary gear 100 is also applicable to the Figure 2 The speed limiting mechanism at the bottom of the middle planetary gear 100.

[0027] Continue to refer to Figure 3 The speed limiting mechanism 300 according to the present invention is described.

[0028] like Figure 3 As shown, the speed limiting mechanism 300 according to the embodiment of the present invention includes an elastic element in the form of a coil spring 301 and a slider 302, and the first groove 101 on the planetary gear 100 is used to accommodate the coil spring 301 in a manner that allows the coil spring 301 to freely expand and contract, and the second groove 102 on the planetary gear 100 is used to accommodate the slider 302 in a manner that allows the slider 302 to freely swing. As already mentioned, Figure 2 As described above, the first groove 101 and the second groove 102 are configured to communicate with each other, thereby enabling the coil spring 301 to directly apply elastic force to the slider 302. In addition, the elastic force of the coil spring 301 has a component force in the radial direction, so that the first surface (bottom surface) of the slider 302 is pressed against the planetary gear shaft 200.

[0029] Figure 4 The speed limiting mechanism in the differential according to the embodiment of the present invention is shown in a first working condition. Figure 5 FIG. 2 shows a speed limiting mechanism in a differential in a second working condition according to an embodiment of the present invention. Figure 4 and Figure 5 The following describes situations where the differential according to the embodiment of the present invention is in a first operating condition and a second operating condition respectively.

[0030] Figure 4 It shows that the speed limiting mechanism in the differential according to the embodiment of the present invention is in a first working condition. In the first working condition, the rotation speed of the planetary gear 100 is lower than the rotation speed threshold. Figure 5 It is shown that the speed limiting mechanism in the differential according to the embodiment of the present invention is in the second working condition. In the second working condition, the rotation speed of the planetary gear 100 is higher than the rotation speed threshold.

[0031] like Figure 4As shown, when the rotational speed of the planetary gear 100 is lower than the rotational speed threshold, the slider 302 is subjected to the first elastic force exerted by the coil spring 301 and the first centrifugal force caused by the rotation. Under the action of both the first elastic force and the first centrifugal force, the bottom surface of the slider 302 slides on the planetary gear shaft 200 at the first contact point C1. It can be understood that the state of the slider 302 is stable at this time, and under the action of both the first elastic force and the first centrifugal force, the bottom surface of the slider 302 always and stably slides on the planetary gear shaft 200 at the first contact point C1. The friction force between the slider 302 and the planetary gear shaft 200 is recorded as the first friction force.

[0032] like Figure 5 As shown, when the planetary gear 100 rotates at a speed higher than a threshold, the slider 302 is subjected to the second elastic force exerted by the coil spring 301 and the second centrifugal force caused by the rotation. Under the combined effects of the second elastic force and the second centrifugal force, the bottom surface of the slider 302 slides on the planetary gear shaft 200 at the second contact point C2. It will be appreciated that when the planetary gear 100 rotates too fast, the second centrifugal force exerted on the slider 302, which rotates along with the planetary gear 100, will become greater than the second elastic force. In this case, the slider 302 will move away from the planetary gear shaft 200. Because the slider 302 is positioned within the second slot 102, which is slightly larger than the slider 302, the slider 302 can freely swing left and right within the second slot 102 while being constrained by the second slot 102. During this swinging motion, the slider 302 will slide on the planetary gear shaft 200 at the second contact point C2 on its bottom surface for a period of time. At this time, the slider 302 is in an unstable state, and under the action of both the second elastic force and the second centrifugal force, the bottom surface of the slider 302 slides intermittently on the planetary gear shaft 200 at the second contact point C2. The friction force between the slider 302 and the planetary gear shaft 200 is recorded as the second friction force.

[0033] exist Figure 4 When the speed limiting mechanism 300 of the differential shown in FIG is in the first working condition, the slider 302 slides on the planetary gear shaft 200 with the first contact point C1 on the bottom surface, and a first friction force is generated between the slider 302 and the planetary gear shaft 200; Figure 5 When the speed limiting mechanism 300 of the differential shown in FIG is in the second working condition, the slider 302 slides on the planetary gear shaft 200 with the second contact point C2 on the bottom surface, and a second friction force is generated between the slider 302 and the planetary gear shaft 200. Figure 4 and Figure 5 It can be clearly seen that when the slider 302 is in Figure 5 In the second working condition, the slider 302 is relatively Figure 4The first working condition shown in FIG is away from the planetary gear shaft 200, so that the upper left end of the slider 302 moves upward and the lower right end thereof approaches the planetary gear shaft 200. Therefore, the second contact point C2 on the bottom surface of the slider 302 is closer to the edge of the bottom surface of the slider 302 (specifically, the right edge of the bottom surface of the slider 302 in this embodiment) than the first contact point C1. Based on the principle that the hypotenuse is larger than the right angle side, Figure 5 When the lower right end contacts the planetary gear shaft, the pressure between the slider 302 and the planetary gear shaft 200 is greater than Figure 4 The pressure between the slider 302 and the planetary gear shaft 200 when the middle portion shown contacts the planetary gear shaft, and accordingly, Figure 5 When the lower right end contacts the planetary gear shaft, the friction between the slider 302 and the planetary gear shaft 200 is greater than Figure 4 The friction force between the slider 302 and the planet pin 200 is shown when the middle portion contacts the planet pin.

[0034] Therefore, in the differential 10 of the embodiment of the present invention, when the rotational speed of the planetary gear 100 is below the speed threshold, the slider 302 slides on the planetary gear shaft 200 at the first contact point C1, under the action of both the first elastic force exerted by the coil spring 301 and the first centrifugal force. Furthermore, when the rotational speed of the planetary gear 100 exceeds the speed threshold, the slider 302 slides on the planetary gear shaft 200 at the second contact point C2, under the action of both the second elastic force of the coil spring 301 and the second centrifugal force. Because the second contact point C2 is closer to the side of the slider 302 than the first contact point C1, the friction force between the slider 302 and the planetary gear shaft 200 at the second contact point C2 is greater than the friction force between the slider 302 and the planetary gear 100 at the first contact point C1. As the friction force on the slider 302 and the planetary gear 100 increases, the rotational speed decreases, thereby limiting the speed of the differential.

[0035] Therefore, the differential of the present invention, by providing a speed limiting mechanism to limit the rotational speed of the planetary gears, avoids the problem of excessively high rotational speeds in conventional differentials, thereby preventing the problem of excessively high differential speeds causing differential components to be exposed to excessively high ambient temperatures. As a result, the differential of the present invention is protected from damage caused by high temperatures, thereby extending its service life.

[0036] As a preferred embodiment of the present invention, the sliding block is configured to have rounded corners, thereby avoiding scratching of the planetary gear shafts in the differential, further ensuring that the differential of the present invention has a longer service life.

[0037] Those skilled in the art will appreciate that the above embodiments are merely examples. The differential of the present invention is not limited thereto. For example, the number of speed limiting mechanisms of the differential of the present invention is not limited to two, and one or more speed limiting mechanisms may be provided. Furthermore, when multiple speed limiting mechanisms are provided, the multiple speed limiting mechanisms are not limited to being identical to one another, and may be provided so that some of the speed limiting mechanisms are identical or completely different. For another example, the elastic element of the speed limiting mechanism is not limited to a coil spring, and any elastic element that can provide elastic force may be used in the present invention. For another example, the elastic element is not limited to applying force directly to the slider, and those skilled in the art may, according to actual circumstances, set the elastic element to apply force indirectly to the slider. For another example, the first and second grooves in the planetary gear are not limited to forming through holes, and those skilled in the art may, according to actual circumstances, set the first groove to a groove that is not visible from the outside of the planetary gear.

[0038] As mentioned above, although the exemplary embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments, and the protection scope of the present invention should be defined by the claims and their equivalents.

Claims

1. A differential (10), comprising a planetary gear (100) and a planetary gear shaft (200), wherein the planetary gear (100) is rotatable relative to the planetary gear shaft (200). It is characterized by: The invention also includes a speed limiting mechanism (300) provided on the planetary gear (100), wherein the speed limiting mechanism (300) includes an elastic element and a slider (302). When the rotation speed of the planetary gear (100) is lower than a rotation speed threshold, the slider (302) slides on the planetary gear shaft (200) at a first contact point (C1) on a first surface under the action of both a first elastic force and a first centrifugal force applied by the elastic element. When the rotation speed of the planetary gear (100) is higher than the rotation speed threshold, the slider (302) slides on the planetary gear shaft (200) at a second contact point (C2) on the first surface under the action of both a second elastic force and a second centrifugal force applied by the elastic element. The second contact point (C2) is closer to the edge of the first surface of the slider (302) than the first contact point (C1), so that the friction force when the slider (302) contacts the planetary gear shaft (200) at the second contact point (C2) is greater than the friction force when the slider (302) contacts the planetary gear shaft (200) at the first contact point (C1).

2. The differential (10) according to claim 1, wherein: The planetary gear (100) is provided with a first groove (101) and a second groove (102), wherein the first groove (101) is used to accommodate the elastic element in a manner allowing the elastic element to freely expand and contract, and the second groove (102) is used to accommodate the slider (302) in a manner allowing the slider (302) to freely swing.

3. The differential (10) according to claim 2, wherein: The first groove (101) and the second groove (102) are configured to communicate with each other so that the elastic element directly applies elastic force to the slider (302).

4. The differential (10) according to claim 3, wherein: The first groove (101) is configured to extend in a direction forming a certain angle with the radial direction of the planetary gear (100), and the elastic force of the elastic element has a component force in the radial direction so that the slider (302) is pressed onto the planetary gear shaft (200).

5. The differential (10) according to claim 4, wherein: Two speed limiting mechanisms (300) are provided on the planetary gear (100), and the two speed limiting mechanisms (300) are configured to be 180 degrees apart from each other.

6. The differential (10) according to claim 5, wherein: The elastic element of the speed limiting mechanism (300) is configured as a coil spring (301).

7. The differential (10) according to claim 6, wherein: The slider (302) is configured to have rounded corners.

8. The differential (10) according to claim 7, wherein: The first groove (101) and the second groove (102) are configured as through holes formed on the planetary gear (100).

9. The differential (10) according to claim 8, wherein: The two speed limiting mechanisms (300) are constructed identically to each other.

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