Limited slip differential

Abstract

The present invention provides a limited slip differential comprising: a differential limiting carrier mounted on a first output shaft; a differential limiting ring gear mounted on a second output shaft facing the first output shaft; a piston mounted on the differential limiting ring gear; a rod having one end penetrating the differential limiting ring gear so as to face the piston; and a sleeve connected to the other end of the rod and inserted in the operating space of the differential limiting ring gear.

Description

limited slip differential

[0001] The present invention relates to a differential limiting device mounted on an electric axle (eAxle).

[0002] In general, differential gears make it impossible to escape if one of the driving wheels gets stuck on rough roads such as ice, a puddle, or sand, and the driving wheels may slip when accelerating up a steep hill. When braking on a snowy road, the driving wheels may lose traction and the vehicle may skid, making it impossible to control the vehicle.

[0003] To address the shortcomings of differential gears, the limited slip differential (LSD) was developed. A limited slip differential (LSD) is a device that limits differential movement. When the rotational speeds of the two drive wheels differ beyond a certain level, the LSD sends a portion of the driving force to the drive wheel with the lower rotational speed, ensuring that the difference in rotational speeds remains constant.

[0004] Conventional limited-slip differentials applied to medium and large-sized mass-produced trucks may include a differential lock sleeve, a rod, and a fork. Conventional limited-slip differentials, when operating a limited-slip differential, cause the rod to move in the limited-slip direction by air pressure applied to the inside of the housing through an air coupler, and at the same time, the fork coupled to the rod moves in the limited-slip direction together with the rod, thereby engaging the dog clutch, thereby achieving a limited-slip differential state.

[0005] However, the electric axle (eAxle) has many components in the chassis, such as the battery pack, and the electric axle (eAxle) itself must include a motor, so it has insufficient installation space and is large compared to an internal combustion engine axle, so it is not possible to use components such as the shaft of a conventional limited slip differential.

[0006] In addition, since the conventional limited-slip differential device is a device that limits the differential by the differential gear, it cannot be applied to an electric axle (eAxle) equipped with a planetary gear set.

[0007] [Prior Art Literature]

[0008] [Patent Document]

[0009] (Patent Document 1) Republic of Korea Patent Publication No. 10-2014-0120478 (published on October 14, 2014)

[0010] In order to solve the above-mentioned problem, the present invention seeks to provide a differential limiting device suitable for an electric axle (eAxle).

[0011] In order to achieve the above-described object, the present invention provides a differential limited-slip device comprising: a differential limited-slip carrier mounted on a first output shaft; a differential limited-slip ring gear mounted on a second output shaft opposite to the first output shaft; a piston mounted on the differential limited-slip ring gear; a rod having one end penetrating the differential limited-slip ring gear and directed toward the piston; and a sleeve connected to the other end of the rod and inserted into an operating space of the differential limited-slip ring gear; wherein, when the piston presses the rod by air pressure, the sleeve connected to the rod is pushed toward the differential limited-slip carrier, and a first dog clutch provided on one surface of the sleeve is engaged with a second dog clutch provided on one surface of the differential limited-slip carrier.

[0012] In addition, the sleeve and the differential limited-slip carrier are elastically supported by an elastic member, and the elastic member may have one end inserted into a first receiving portion of the sleeve provided inside the first dog clutch, and the other end inserted into a second receiving portion of the differential limited-slip carrier provided inside the second dog clutch.

[0013] Additionally, the elastic member may be supported by a first support member having one end coupled to the first receiving portion, and the other end may be supported by a second support member having the other end coupled to the second receiving portion.

[0014] Additionally, the first support member may be a retainer.

[0015] Additionally, the first support member may be supported by a first bearing that is first coupled to the first receiving portion.

[0016] Additionally, the second support member may be a washer.

[0017] Additionally, the sleeve can be spline-coupled to the operating space with the outer diameter portion inserted into the operating space.

[0018] Additionally, one end of the load is coupled to a pressure member, and the pressure member can be pressured by the piston.

[0019] Additionally, a second bearing may be provided between the pressurizing member and the piston.

[0020] In addition, the piston includes a first outer diameter portion to which a first sealing member is coupled; and a second outer diameter portion having an outer diameter larger than the first outer diameter portion and to which a second sealing member is coupled; and a housing is coupled inside the axle case, the first sealing member is in close contact with the first inner diameter portion provided inside the housing, the second sealing member is in close contact with the second inner diameter portion provided inside the housing, and the second outer diameter portion can be restricted from moving by being caught on a step provided at a boundary between the first inner diameter portion and the second inner diameter portion.

[0021] Additionally, the differential limited carrier and the differential limited ring gear can be connected to a planetary gear set for power.

[0022] In addition, the planetary gear set may include a sun gear coupled to a hub of the differential limited carrier; a ring gear configured to surround the sun gear; a first planetary gear that meshes with an outer diameter of the sun gear and an inner diameter of the ring gear between the sun gear and the ring gear, and is rotatable while connected to the differential limited carrier; and a second planetary gear whose outer diameter meshes with an outer diameter of the gear part and the ring gear between the gear part of the differential limited ring gear and the ring gear.

[0023] In addition, a fixing member is coupled to the housing, and the fixing member penetrates the housing and is inserted into a coupling groove provided between the first outer diameter portion and the second outer diameter portion of the piston, and the length of the coupling groove can be configured to be a length that matches the linear reciprocating motion of the piston so that the linear reciprocating motion of the piston is possible.

[0024] The present invention can provide a differential limiting device optimized for an electric axle (eAxle).

[0025] In addition, the present invention can significantly reduce the number of parts compared to existing differential limiting devices by simplifying the function, thereby reducing cost and weight.

[0026] FIG. 1 is a drawing showing a state in which a differential limiting device is mounted on an electric axle according to a preferred embodiment of the present invention.

[0027] Figure 2 is an enlarged view of part A of Figure 1.

[0028] FIG. 3 is an enlarged view showing a first support member and a second support member supporting an elastic member according to a preferred embodiment of the present invention.

[0029] FIG. 4 is a drawing showing the operation of a differential limiting device according to a preferred embodiment of the present invention.

[0030] FIG. 5 is a drawing showing the power flow when the first dog clutch and the second dog clutch are engaged according to a preferred embodiment of the present invention.

[0031] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. First, when assigning reference numerals to components in each drawing, it should be noted that identical components are assigned the same numerals as much as possible even if they are shown in different drawings. Furthermore, in describing the present invention, if a detailed description of a related known structure or function is judged to obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, although preferred embodiments of the present invention will be described below, it should be understood that the technical idea of ​​the present invention is not limited thereto and can be modified and implemented in various ways by those skilled in the art.

[0032] FIG. 1 is a drawing showing a state in which a differential limiting device is mounted on an electric axle according to a preferred embodiment of the present invention, FIG. 2 is an enlarged view of part A of FIG. 1, and FIG. 3 is an enlarged view showing a first support member and a second support member supporting an elastic member according to a preferred embodiment of the present invention.

[0033] As illustrated in FIGS. 1 to 3, the present invention may include a differential limit carrier (10), a differential limit ring gear (20), a piston (30), a rod (40), and a sleeve (50).

[0034] The differential carrier (10), the differential ring gear (20), the piston (30), the rod (40), and the sleeve (50) can be mounted inside the axle case (AC). The differential carrier (10) and the differential ring gear (20) can be powered by a planetary gear set mounted inside the axle case (AC).

[0035] The planetary gear set may include a sun gear (S), a ring gear (R), a first planetary gear (P1), and a second planetary gear (P2).

[0036] The sun gear (S) can be coupled to the hub (11) of the differential limited-slip carrier (10). Power from a power source such as a drive motor (not shown) can be transmitted to the sun gear (S). The ring gear (R) can be configured to surround the sun gear (S).

[0037] The first planetary gear (P1) may be positioned between the sun gear (S) and the ring gear (R). The first planetary gear (P1) may mesh with the outer diameter of the sun gear (S) and the inner diameter of the ring gear (R). The first planetary gear (P1) may be connected to the differential limiting carrier (10) by a connecting member (13) such as a pin. The first planetary gear (P1) may rotate about the connecting member (13).

[0038] The second planetary gear (P2) can be positioned between the gear portion (22) of the differential limited ring gear (20) and the ring gear (R). The outer diameter of the second planetary gear (P2) can be meshed with the gear portion (22) of the differential limited ring gear (20) and the outer diameter of the ring gear (R).

[0039] The second planetary gear (P2) can be rotatably connected to a carrier (not shown). The carrier (not shown) connected to the second planetary gear (P2) can be fixed inside the axle case (AC).

[0040] A differential limited slip carrier (10) can be mounted on one side of a first output shaft (DS1). The first output shaft (DS1) can be connected to one side of a driving wheel (DW1).

[0041] A differential limited-slip ring gear (20) may be mounted on the second output shaft (DS2) on the other side. The second output shaft (DS2) may be configured to face the first output shaft (DS1) inside the axle case (AC). The first output shaft (DS1) and the second output shaft (DS2) may be positioned coaxially.

[0042] The piston (30) may be mounted on the differential limited-slip ring gear (20). The piston (30) may include a first outer diameter portion (31) and a second outer diameter portion (32). A first sealing member (SL1) may be coupled to the first outer diameter portion (31). The second outer diameter portion (32) may have an outer diameter larger than that of the first outer diameter portion (31). A second sealing member (SL2) may be coupled to the second outer diameter portion (32).

[0043] A housing (80) may be coupled inside an axle case (AC). A piston (30) may be coupled inside the housing (80). A first sealing member (SL1) may be in close contact with a first inner diameter portion (81) provided inside the housing (80) to form a sealed structure. A second sealing member (SL2) may be in close contact with a second inner diameter portion (82) provided inside the housing (80) to form a sealed structure.

[0044] The second outer diameter portion (32) of the piston (30) can be restricted from moving in the opposite direction of the differential restriction by being caught by a step (83) provided at the boundary between the first inner diameter portion (81) and the second inner diameter portion (82).

[0045] By means of a fixed member (F) coupled to the housing (80), the piston (30) can only perform linear reciprocating motion, and rotation can be limited.

[0046] A fixing member (F) can be coupled to the housing (80). The fixing member (F) can be inserted into a coupling groove (33) provided between the first outer diameter portion (31) and the second outer diameter portion (32) of the piston (30) through the housing (80). The length (L) of the coupling groove (33) can be configured to be a length that matches the linear reciprocating motion of the piston (30) so that the linear reciprocating motion of the piston (30) is possible.

[0047] Due to the structure in which the fixed member (F) is inserted into the connecting groove (33), the piston (30) can perform linear reciprocating motion, but rotation is impossible because the connecting groove (33) is caught on the fixed member (F).

[0048] One end of the rod (40) can pass through the differential limiting ring gear (20) and face the piston (30).

[0049] The sleeve (50) can be connected to the other end of the load (40). The sleeve (50) can be inserted into the operating space (21) inside the differential limiting ring gear (20).

[0050] Air pressure can be supplied into the housing (80). The piston (30) can pressurize the rod (40) by the air pressure supplied into the housing (80). As the piston (30) pressurizes the rod (40), the sleeve (50) connected to the rod (40) can be pushed toward the differential carrier (10).

[0051] As the sleeve (50) is pushed toward the differential limit carrier (10), the first dog clutch (51a) provided on one side of the sleeve (50) can be engaged with the second dog clutch (12a) provided on one side of the differential limit carrier (10).

[0052] As the first dog clutch (51a) and the second dog clutch (12a) are engaged, a differential limited state can be achieved in which the differential limited carrier (10) and the differential limited ring gear (20) rotate as one unit. In the differential limited state, power can be transmitted in both directions to the differential limited carrier (10) and the differential limited ring gear (20) that rotate as one unit via the planetary gear set.

[0053] Power transmitted to the differential limited-slip carrier (10) can be transmitted to one drive wheel (DW1) via the first output shaft (DS1). Power transmitted to the differential limited-slip ring gear (20) can be transmitted to the other drive wheel (DW2) via the second output shaft (DS2). This allows for easy escape even if one drive wheel (DW1) or the other drive wheel (DW2) gets stuck on a rough road such as ice, a puddle, or sand.

[0054] The sleeve (50) and the differential limit carrier (10) can be elastically supported by an elastic member (60). One end of the elastic member (60) can be inserted into a first receiving portion (51b) of the sleeve (50). The other end of the elastic member (60) can be inserted into a second receiving portion (12b) of the differential limit carrier (10). For example, the elastic member (60) can be a return spring.

[0055] The first receiving portion (51b) may be formed in the sleeve (50) portion inside the first dog clutch (51a). The second receiving portion (12b) may be formed in the differential limit carrier (10) portion inside the second dog clutch (12a).

[0056] One end of the elastic member (60) may be supported by a first support member (91). The first support member (91) may be coupled to a first receiving portion (51b). The first support member (91) may be a retainer. The first support member (91) may be supported by a first bearing (B1) that is first coupled to the first receiving portion (51b).

[0057] In this way, since one end of the elastic member (60) does not directly contact the first receiving portion (51b) but is supported by the first supporting member (91), wear of the first receiving portion (51b) due to contact with the elastic member (60) can be prevented.

[0058] The other end of the elastic member (60) may be supported by a second support member (92). The second support member (92) may be coupled to the second receiving portion (12b). The second support member (92) may be a washer.

[0059] In this way, since the other end of the elastic member (60) does not directly contact the second receiving portion (12b) but is supported by the second supporting member (92), wear of the second receiving portion (12b) due to contact with the elastic member (60) can be prevented.

[0060] The outer diameter of the sleeve (50) can be spline-coupled (SP) to the operating space (21) while being inserted into the operating space (21) of the differential limiting ring gear (20).

[0061] The sleeve (50) can be engaged with the differential limited ring gear (20) and the first dog clutch (51a) in a spline (SP)-engaged state to the second dog clutch (12a) of the differential limited carrier (10). The differential limited carrier (10) and the differential limited ring gear (20) can be synchronized by the engagement of the first dog clutch (51a) and the second dog clutch (12a).

[0062] One end of the rod (40) may be coupled to a pressure member (70). The pressure member (70) may be a retainer. The pressure member (70) may be positioned in the second inner diameter (82) of the housing (80). The pressure member (70) may be pressurized by the piston (30).

[0063] A second bearing (B2) may be provided between the pressurizing member (70) and the piston (30). The second bearing (B2) may be supported by a washer (W). The differential ring gear (20) is disconnected from the piston (30) by the second bearing (B2), so that even if the differential ring gear (20) rotates, the piston (30) is not affected at all.

[0064] The following describes the operation of the differential limiting device of the present invention.

[0065] FIG. 4 is a drawing showing the operation of a differential limiting device according to a preferred embodiment of the present invention.

[0066] As shown in Fig. 4, when air pressure is supplied to the inside of the housing (80), the piston (30) can move toward the pressure member (70) and pressurize the pressure member (70).

[0067] As the pressurizing member (70) is pressurized by the piston (30), the rod (40) having one end connected to the pressurizing member (70) can be pressurized. As the rod (40) is pressurized, the sleeve (50) having the other end connected to the rod (40) can be pressurized.

[0068] As the sleeve (50) is pressurized, the first dog clutch (51a) of the sleeve (50) moves toward the second dog clutch (12a) of the differential carrier (10), so that the first dog clutch (51a) can be engaged with the second dog clutch (12a).

[0069] During the process of engaging the first dog clutch (51a) with the second dog clutch (12a), the elastic member (60) can be compressed by being pushed against the sleeve (50). When the pressure of the piston (30) disappears, the elastic member (60) can extend to its original state and push the sleeve (50) to its original position.

[0070] Since the sleeve (50) is engaged with the differential ring gear (20) and the spline (SP) engagement state, the first dog clutch (51a) is engaged with the second dog clutch (12a) of the differential carrier (10), so that the differential carrier (10) and the differential ring gear (20) can rotate as one.

[0071] Since power is simultaneously transmitted to one driving wheel (DW1) connected to the differential limited carrier (10) and the other driving wheel (DW2) connected to the differential limited ring gear (20) in the differential limited lock state where the first dog clutch (51a) and the second dog clutch (12a) are engaged, even if one driving wheel (DW1) or the other driving wheel (DW2) gets stuck on a rough road such as ice, a puddle, or sand, it is possible to easily escape.

[0072] The following describes the power flow when the differential is limited according to the present invention.

[0073] FIG. 5 is a drawing showing the power flow when the first dog clutch and the second dog clutch are engaged according to a preferred embodiment of the present invention.

[0074] As shown in Fig. 5, in a differential limited state where the first dog clutch (51a) and the second dog clutch (12a) are engaged, power from a power source such as a drive motor (not shown) can be transmitted to the sun gear (S).

[0075] The power transmitted to the sun gear (S) can be transmitted to the first output shaft (DS1) through the differential limited carrier (10) connected to the sun gear (S) and at the same time, transmitted to the second output shaft (DS2) through the first planetary gear (P1), the ring gear (R), the second planetary gear (P2), and the differential limited ring gear (20).

[0076] Power transmitted to the first output shaft (DS1) can be transmitted to one driving wheel (DW1), and power transmitted to the second output shaft (DS2) can be transmitted to the other driving wheel (DW2).

[0077] In this way, since power is transmitted simultaneously to one driving wheel (DW1) and the other driving wheel (DW2), even if one driving wheel (DW1) or the other driving wheel (DW2) gets stuck on a rough road such as ice, a puddle, or sand, the driving wheel stuck on the rough road can easily escape without spinning.

[0078] As discussed above, the present invention can provide a limited-slip differential optimized for an electric axle equipped with a planetary gearset. The present invention eliminates the need for components such as rods and forks found in conventional limited-slip differentials. Furthermore, the present invention allows the piston to perform a differential shifting function.

[0079] The above description is merely an illustrative description of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications, changes, and substitutions may be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical idea of ​​the present invention, but rather to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments and the accompanying drawings. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. Differential limited slip carrier mounted on the first output shaft; A differential limited-slip ring gear mounted on a second output shaft opposite to the first output shaft; A piston mounted on the above differential limited-slip ring gear; A rod having one end penetrating the differential ring gear and directed toward the piston; and A sleeve connected to the other end of the above load and inserted into the operating space of the differential limiting ring gear; Including, A differential limiting device characterized in that, as the piston presses the rod by air pressure, the sleeve connected to the rod is pushed in the direction of the differential limiting carrier, and the first dog clutch provided on one side of the sleeve is engaged with the second dog clutch provided on one side of the differential limiting carrier.

2. In paragraph 1, A differential limited-slip device characterized in that the sleeve and the differential limited-slip carrier are elastically supported by an elastic member, and the elastic member has one end inserted into a first receiving portion of the sleeve provided inside the first dog clutch, and the other end inserted into a second receiving portion of the differential limited-slip carrier provided inside the second dog clutch.

3. In paragraph 2, The above elastic member is, A differential limiting device characterized in that one end is supported by a first support member coupled to the first receiving portion, and the other end is supported by a second support member coupled to the second receiving portion.

4. In paragraph 3, The above first support member, A differential limited slip device characterized by a retainer.

5. In paragraph 4, The above first support member, A differential limiting device characterized in that it is supported by a first bearing that is first coupled to the first receiving portion.

6. In paragraph 3, The above second support member, A differential lock characterized by being a washer.

7. In paragraph 1, The above sleeve, A differential limiting device characterized in that the outer diameter is spline-coupled to the operating space while being inserted into the operating space.

8. In paragraph 1, A differential limiting device characterized in that one end of the above load is connected to a pressure member, and the pressure member is pressured by the piston.

9. In paragraph 8, A differential limiting device characterized in that a second bearing is provided between the pressurizing member and the piston.

10. In paragraph 1, The above piston, A first outer diameter portion to which a first sealing member is joined; and A second outer diameter portion having an outer diameter larger than the first outer diameter portion and to which a second sealing member is joined; Including, A differential limited slip device characterized in that a housing is coupled inside an axle case, the first sealing member is in close contact with a first inner diameter portion provided inside the housing, the second sealing member is in close contact with a second inner diameter portion provided inside the housing, and the second outer diameter portion is caught on a step provided at a boundary between the first inner diameter portion and the second inner diameter portion and movement is restricted.

11. In paragraph 1, A differential limiting device characterized in that the differential limiting carrier and the differential limiting ring gear are connected to a planetary gear set and power.

12. In paragraph 11, The above planetary gear set is, A sun gear coupled to the hub of the above differential limited slip carrier; A ring gear configured to surround the above-mentioned sun gear; A first planetary gear that is engaged with the outer diameter of the sun gear and the inner diameter of the ring gear between the sun gear and the ring gear, and is rotatable while connected to the differential limit carrier; and A second planetary gear having an outer diameter meshed between the gear portion of the above differential limited ring gear and the ring gear; A differential lock including a .

13. In paragraph 10, A differential limiting device characterized in that a fixing member is coupled to the housing, the fixing member penetrates the housing and is inserted into a coupling groove provided between the first outer diameter portion and the second outer diameter portion of the piston, and the length of the coupling groove is configured to be a length corresponding to the linear reciprocating motion of the piston so that the linear reciprocating motion of the piston is possible.

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