Differential gear device

Abstract

This utility model relates to a differential gear device capable of miniaturizing the outer diameter of the receiving portion in a differential housing. The differential gear device (1) is equipped with: a housing member (2) having a cylindrical receiving portion (5) and being rotatably held; a pinion (9) rotatably disposed and disposed on the inner side of the receiving portion (5) about the central axis of the receiving portion (5); and two half-shaft gears (3, 4) meshing with the pinion (9), wherein the pinion (9) is equipped with: a solid gear portion (9a) composed of bevel gears meshing with the two half-shaft gears (3, 4); and a solid retaining shaft portion (9b) integrally formed on the gear portion (9a) and protruding to the outer periphery of the receiving portion (5), and the housing member (2) having a fitting hole (11) into which the retaining shaft portion (9b) is inserted.

Description

Technical Field

[0001] This utility model relates to a differential gear device that can connect the left and right wheels in a differential rotation. Background Technology

[0002] Traditional differential gear systems typically consist of multiple pinions, two axle gears meshing with the pinions, and a cylindrical differential housing housing the pinions and axle gears. The differential housing has two through holes facing each other in the radial direction. The pinion shafts are fitted into these through holes, and each pinion is rotatably fitted into the pinion shaft. Additionally, a retaining pin, used to prevent the pinion shaft from disengaging from the differential housing, passes through and is inserted into the radial direction of the pinion shaft.

[0003] Patent Document 1 describes a differential gear device configured to retain the pinion by rotation without the aforementioned pinion shaft, thereby reducing the number of components in the differential gear device and simplifying assembly processes. This differential gear device has two recesses spaced 180 degrees apart in the rotational direction of the differential housing. Each recess consists of a concave spherical bottom portion and a circularly shaped hole portion that fits into a portion of the pinion. Furthermore, the pinion is a bevel gear with a cylindrical portion formed on the side opposite to its toothed end in the axial direction, and its end face is formed into a convex spherical shape that matches the bottom portion of the recess. Thus, this differential gear device is configured such that, when a radial load is applied to the pinion, the movement of the pinion is restricted by the contact between the cylindrical portion and the hole portion.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-275042 Utility Model Content

[0007] The problem to be solved by the utility model

[0008] The differential gear device described in Patent Document 1 accommodates and positions a portion of a pinion in a recess formed in the differential housing, thereby reducing the pinion shaft used to hold the pinion. This allows the engagement length between the hole formed in the differential housing and the cylindrical portion formed in the pinion to be sufficient to withstand a load acting in the radial direction of the pinion. Furthermore, the plate thickness of the differential housing at the location of the recess is sufficient to withstand the centrifugal force acting on the pinion as it revolves. Therefore, since the differential housing plate thickness requires both the thickness for forming the hole and the thickness for withstanding the centrifugal force acting on the pinion, there is room for further technical improvements to reduce the outer diameter of the differential housing.

[0009] This utility model was developed in response to the aforementioned technical issues, and its purpose is to provide a differential gear device that can reduce the outer diameter of the differential housing.

[0010] Methods for solving problems

[0011] To achieve the above objectives, this utility model provides a differential gear device, comprising: a housing member having a cylindrical receiving portion and being rotatably held about the central axis of the receiving portion; a pinion rotatably disposed and revolving about the central axis of the receiving portion on the inner side of the receiving portion; and two half-shaft gears arranged opposite to each other along the central axis of the receiving portion and meshing with the pinion, characterized in that the pinion is equipped with: a solid gear portion consisting of bevel gears meshing with the two half-shaft gears; and a solid retaining shaft portion integrally formed on the gear portion and protruding towards the outer periphery of the receiving portion, wherein the housing member has a fitting hole into which the retaining shaft portion is inserted.

[0012] Effects of the utility model

[0013] According to this invention, a pinion is housed in a cylindrical housing. The pinion consists of a solid gear portion and a solid retaining shaft portion. The gear portion is a bevel gear, and the retaining shaft portion is integrally formed on the gear portion and inserted into a fitting hole formed in a housing member. Therefore, since no fixing pin or other fixing member is provided, the movement of the pinion in the axial direction can be restricted. Thus, there is no need to provide space in the housing member for fixing members, allowing for miniaturization of the housing member in the radial direction. Furthermore, since the movement of the pinion in the longitudinal or circumferential direction of the housing member can be restricted by fitting the retaining shaft portion into the fitting hole, there is no need to form a stepped portion or the like on the inner surface of the housing member for abutting against the outer circumferential surface of the pinion, allowing for miniaturization of the housing member in the radial direction. Moreover, by forming the gear portion and retaining shaft portion as solid, there is no need for a plate thickness sufficient to fit the pinion into a pinion shaft and ensure the strength of the fitting portion, allowing for miniaturization (diameter reduction) of the pinion. As a result, it is possible to reduce the plate thickness of the housing components required to withstand the centrifugal force acting on the pinion, and to miniaturize the housing components in the radial direction. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view illustrating an example of a differential gear device in an embodiment of the present invention.

[0015] Explanation of reference numerals in the attached figures:

[0016] 1 Differential gear assembly, 2 Differential housing, 3, 4 Half-shaft gears, 3a, 4a Gear sections, 5 Receiving section, 5a Cylindrical section, 6 Cover section, 6c, 6d, 7a, 11, 12a Through holes, 7 Gear ring, 9 Pinion, 9a Gear section, 9b Retaining shaft section Detailed Implementation

[0017] The present invention will now be described based on the embodiments shown in the accompanying drawings. Furthermore, the embodiments described below are merely one example of how to embody the present invention and do not limit the scope of the invention.

[0018] exist Figure 1 The diagram shows a cross-sectional view illustrating an example of a differential gear device in an embodiment of the present invention. Figure 1 The differential gear device 1 shown is configured to cause the housing component (hereinafter referred to as the differential housing) 2, the right half-shaft gear 3, and the left half-shaft gear 4 to rotate differentially.

[0019] The differential housing 2 is constructed by integrating a cylindrical receiving portion 5, an annular cover portion 6, and a gear ring 7 using bolts 8. The receiving portion 5 houses each half-shaft gear 3, 4. One of the cover portion 6 and the receiving portion 5 ( Figure 1The gear ring 7 (left side of the figure) abuts against the open end, and meshes with the output gear of the power transmission device such as the speed change mechanism not shown in the figure.

[0020] The housing 5 is composed of a cylindrical part 5a, a flange part 5b, a reduced diameter part 5c, and a cylindrical right-side boss part 5d. The cylindrical part 5a houses the pinion 9, which will be described later, and the various half-shaft gears 3 and 4 inside. The flange part 5b is formed at one end of the cylindrical part 5a. Figure 1 The left end of the cylindrical part 5a has a gradually narrowing diameter from the other end of the cylindrical part 5a, and the right boss part 5d extends outward from the end of the narrowing diameter part 5c towards the axis of the cylindrical part 5a. Figure 1 (Extends from the right side). Additionally, a plurality of female threaded portions 5e are formed at predetermined intervals in the circumferential direction on the flange portion 5b. Furthermore, window holes for inserting pinion 9, etc., which will be described later, may be formed in the cylindrical portion 5a or the reduced-diameter portion 5c.

[0021] The cover portion 6 is configured to abut against the end face of the aforementioned flange portion 5b, and an outer side ( ) is formed on its inner circumference toward the central axis of the cylindrical portion 5a. Figure 1 The cover 6 has a cylindrical left-side boss 6a extending from the left side. Additionally, on both sides of the cover 6, there are fitting bosses 6b having an outer diameter approximately the same as the inner diameter of the flange 5b. The cover 6 is positioned such that one side of the fitting boss 6b fits into the flange 5b, aligning the receiving portion 5 and the cover 6 on the same axis. Furthermore, in the cover 6, a through hole 6c is formed corresponding to the female thread 5e formed in the flange 5b. Moreover, in the portion of the cover 6 between the fitting boss 6b and the left-side boss 6a in the radial direction, through holes 6d are formed at predetermined intervals in the circumferential direction of the cover 6.

[0022] The inner diameter of the gear ring 7 is formed to be approximately the same as the outer diameter of the other side (left side) of the fitting boss portion 6b formed on the cover portion 6, and it fits into the fitting boss portion 6b, thereby positioning the gear ring 7 and the cover portion 6 in a manner that arranges them on the same axis. In addition, a through hole 7a is formed on the gear ring 7, corresponding to the female thread portion 5e formed on the flange portion 5b. Thus, the receiving portion 5, the cover portion 6, and the gear ring 7 are assembled side by side in the axial direction, and bolts 8 are inserted into the respective through holes 7a and 6c and tightened into the female thread portion 5e formed on the flange portion 5b, thereby positioning and integrating the receiving portion 5, the cover portion 6, and the gear ring 7 in the circumferential direction.

[0023] Furthermore, the bearings 16 are fitted into the respective bosses 5d and 6a, and the differential housing 2 is held in a position to rotate freely by a gearbox housing or the like (not shown in the figure). That is, the differential housing 2 is configured to rotate about the central axis of the housing 5.

[0024] In the central portion of the aforementioned receiving portion 5 along the axial direction, two through holes 11 are formed at 180-degree intervals along the circumferential direction of the receiving portion 5, and the pinion 9 can be rotatably fitted into each of these through holes 11.

[0025] Since all the pinions 9 are formed with the same shape, the following description will only describe the structure of one pinion 9, omitting the description of the structure of the other pinion 9. The pinion 9 consists of a solid gear portion 9a and a solid retaining shaft portion 9b. The gear portion 9a has bevel gears that mesh with the respective half-shaft gears 3 and 4. The retaining shaft portion 9b is integrally formed with the gear portion 9a and protrudes to the outer periphery of the receiving portion 5. This retaining shaft portion 9b is rotatably fitted into the through hole 11 formed in the receiving portion 5. That is, the radial movement of the pinion 9 is restricted by the receiving portion 5.

[0026] Furthermore, the outer diameter of the gear portion 9a is larger than the outer diameter of the retaining shaft portion 9b. Thus, by fitting the retaining shaft portion 9b into the through hole 11, the inner wall surface of the receiving portion 5 faces the bottom surface of the gear portion 9a. The inner wall surface of the receiving portion 5 facing the bottom surface of the gear portion 9a is formed as a concave spherical surface, and the bottom surface of the gear portion 9a is formed as a convex spherical surface that matches the inner wall surface of the receiving portion 5. Furthermore, to reduce the sliding resistance between the inner wall surface of the receiving portion 5 and the bottom surface of the gear portion 9a, a spherical washer 12 is provided between the receiving portion 5 and the gear portion 9a, the washer 12 being equipped with a through hole 12a through which the retaining shaft portion 9b passes.

[0027] The right-side half-shaft gear 3 is a bevel gear configured to rotate around the central axis of the housing portion 5, meshing with the aforementioned pinions 9. This right-side half-shaft gear 3 consists of a gear portion 3a meshing with the pinions 9, and a rear end portion whose end engages with the right-side boss portion 5d. Figure 1 It is composed of a cylindrical part 3b at the left end of the middle.

[0028] The outer diameter of the gear portion 3a is larger than the inner diameter of the rear end of the right-side boss portion 5d. That is, the bottom surface of the gear portion 3a ( Figure 1 The right side of the gear 3a faces the rear end of the right boss 5d. Furthermore, between the bottom surface of the gear 3a and the rear end of the right boss 5d, a ring-shaped filler plate 13 and a ring-shaped disc spring (cone spring) 14 are arranged. Thus, the right half-shaft gear 3 is pushed by the disc spring 14 towards the pinion 9 in the direction of the rotation center axis of the receiving portion 5, so that the meshing length between the right half-shaft gear 3 and each pinion 9 is appropriate.

[0029] The outer diameter of the cylindrical portion 3b is formed to be approximately the same as the inner diameter of the rear end portion of the right-side boss portion 5d, so that the cylindrical portion 3b fits into the right-side boss portion 5d, thereby positioning the right-side half-shaft gear 3 and the receiving portion 5 in a manner that aligns them on the same axis. Furthermore, the cylindrical portion 3b is configured such that the end of a drive shaft (not shown in the figure) engages with the cylindrical portion 3b. Specifically, spline teeth 3c are formed on the inner circumferential surface of the cylindrical portion 3b, and the spline teeth formed at the end of the drive shaft mesh with these spline teeth 3c.

[0030] The left half-shaft gear 4 is constructed in the same manner as the right half-shaft gear 3, and is arranged opposite to the right half-shaft gear 3. That is, the left half-shaft gear 4 is a bevel gear configured to rotate around the central axis of the housing 5 in a manner that meshes with each of the aforementioned pinions 9. The number of teeth in the gear portion 3a of the right half-shaft gear 3 is the same as the number of teeth in the gear portion 4a of the left half-shaft gear 4, which will be described later. The left half-shaft gear 4 consists of a gear portion 4a that meshes with each of the pinions 9, and a rear end that fits into the left-side boss portion 6a. Figure 1 It is composed of a cylindrical part 4b at the right end of the middle.

[0031] The outer diameter of the gear portion 4a is larger than the inner diameter of the rear end of the left-side boss portion 6a. That is, the bottom surface of the gear portion 4a ( Figure 1 The left side of the gear 4a faces the rear end of the left boss 6a. Furthermore, a ring-shaped filler plate 15 and a ring-shaped disc spring (cone spring) 16 are disposed between the bottom surface of the gear 4a and the rear end of the left boss 6a. Thus, the left half-shaft gear 4 is pushed by the disc spring 16 towards the pinion 9 in the direction of the rotation center axis of the receiving portion 5, so that the meshing length between the left half-shaft gear 4 and each pinion 9 is appropriate.

[0032] The outer diameter of the cylindrical portion 4b is formed to be approximately the same as the inner diameter of the rear end portion of the left-side boss portion 6a, so that the cylindrical portion 4b fits into the left-side boss portion 6a, thereby positioning the left-side half-shaft gear 4 and the receiving portion 5 in a manner that aligns them on the same axis. Furthermore, the cylindrical portion 4b is configured such that the end of a drive shaft (not shown) engages with the cylindrical portion 4b. Specifically, spline teeth 4c are formed on the inner circumferential surface of the cylindrical portion 4b, and the spline teeth formed at the end of the drive shaft mesh with these spline teeth 4c.

[0033] The differential gear assembly 1, constructed as described above, involves sequentially inserting the right half-shaft gear 3, each pinion 9, and the left half-shaft gear 4 into the receiving portion 5. Specifically, the receiving portion 5 is inserted in the order of the filler plate 13, the disc spring 14, and the right half-shaft gear 3. The right half-shaft gear 3 is pushed down, and each pinion 9 is inserted. The retaining shaft portion 9b of the pinion 9 is then inserted into the through hole 11. In this way, by inserting the retaining shaft portion 9b of the pinion 9 into the through hole 11, the right half-shaft gear 3 and the pinion 9 are positioned in the direction of the rotation center axis of the receiving portion 5. Next, the left half-shaft gear 4, the disc spring 16, and the filler plate 15 are inserted into the receiving portion. The cover portion 6 and the gear ring 7 are then assembled into the receiving portion 5 and secured with bolts 8, thereby assembling the differential gear assembly 1. Alternatively, the differential gear assembly 1 can be assembled by inserting the pinion 9 through the window formed in the differential housing 2 after assembling the structural components other than the pinion 9.

[0034] The differential gear device 1, configured as described above, comprises three rotating elements: the differential housing 2, and the individual half-shaft gears 3 and 4, which rotate differentially. That is, when the vehicle equipped with this differential gear device 1 is traveling in a straight line, since the left and right wheels rotate at the same speed, the differential housing 2 and the individual half-shaft gears 3 and 4 rotate at the same speed, and the torque transmitted from the drive force source (not shown) to the differential housing 2 is equally transmitted to each half-shaft gear 3 and 4. However, when the vehicle is turning, the drive wheel on the outer wheel side rotates at a higher speed than the drive wheel on the inner wheel side. In this case, the rotation of the pinion allows relative rotation between the half-shaft gear 3 (4) connected to the outer wheel and the half-shaft gear 4 (3) connected to the inner wheel. In other words, the differential housing 2 rotates at a speed based on the speed of the drive force source, and the individual half-shaft gears 3 and 4 rotate relative to each other. In other words, the differential housing 2 and the individual half-shaft gears 3 and 4 rotate differentially. In addition, the torque transmitted from the driving force source (not shown in the figure) to the differential housing 2 is equally distributed and transmitted to each half-shaft gear 3, 4.

[0035] As described above, the pinion 9 is composed of a bevel gear and meshes with each of the half-shaft gears 3 and 4. Therefore, during the assembly of the differential gear assembly 1, the movement of the pinion 9 on the inner circumference of the housing 5 can be restricted. Furthermore, the retaining shaft portion 9b of the gear 9 is configured such that it is fitted into the through hole 11 formed in the housing 5, and the outer diameter of the gear portion 9a is larger than the outer diameter of the retaining shaft portion 9b. Therefore, during the assembly of the differential gear assembly 1, the movement of the pinion 9 on the outer circumference of the housing 5 can be restricted. Furthermore, when centrifugal force acts on the pinion 9 as the differential housing 2 rotates, the contact between the gear portion 9a and the wall of the housing 5 restricts the movement of the pinion 9 on the outer circumference of the housing 5. That is, the movement of the pinion 9 in the axial direction is restricted.

[0036] Furthermore, since the retaining shaft portion 9b of the pinion 9 is fitted into the through hole 11 formed in the receiving portion 5, the load acting on the pinion 9 from each half-shaft gear 3, 4 during the drive of the differential gear device 1 can be borne by the wall surface of the receiving portion 5. Therefore, movement of the pinion 9 in the longitudinal and circumferential directions of the receiving portion 5 can be suppressed.

[0037] As described above, by not providing a fixing pin or the like, the movement of the pinion 9 in the axial direction during assembly and drive can be restricted. Therefore, there is no need to provide space in the housing 5 for fixing members such as fixing pins, allowing the housing 5 to be miniaturized in the radial direction.

[0038] Furthermore, since the pinion is restricted from moving in the longitudinal and circumferential directions by maintaining the engagement between the shaft portion 9b and the through hole 11, it is not necessary to form a stepped portion or the like that abuts against the outer peripheral surface of the gear portion 9a of the pinion 9 on the inner surface of the housing portion 5. Therefore, the housing portion 5 can be miniaturized in the radial direction without forming such a stepped portion or the like to restrict the movement of the pinion 9. That is, the plate thickness of the portion of the housing portion 5 opposite to the pinion 9 only needs to be sufficient to withstand the load of the pinion 9 in the radial direction toward the housing portion 5, such as the centrifugal force acting on the pinion 9, and the plate thickness of the housing portion 5 can be reduced.

[0039] Furthermore, the gear portion 9a or the retaining shaft portion 9b of the pinion 9 is formed as a solid shape. Therefore, compared to the case where the pinion 9 is fitted into the pinion shaft, the diameter of the pinion 9 can be reduced. This is because the plate thickness of the portion (the end portion of the gear portion 9a) that is required to ensure the minimum diameter of the pinion 9 fitted into the pinion shaft can be reduced, thus increasing the outer diameter of the pinion 9. In this way, by reducing the diameter of the pinion 9, in other words, by miniaturizing it, the centrifugal force acting on the pinion 9 can be reduced. Therefore, the plate thickness of the receiving portion 5 required to withstand the centrifugal force can be reduced, and the receiving portion 5 can be miniaturized in the radial direction. Furthermore, since the spacing between the individual half-shaft gears 3 and 4 can be narrowed by reducing the diameter of the pinion 9, the shaft length of the differential housing 2 can be shortened.

[0040] Furthermore, the differential gear device 1 described above has two pinions 9 provided in the circumferential direction of the housing portion 5. However, it is also possible to provide three or more pinions 9 in the circumferential direction of the housing portion 5. In addition, in the housing portion 5, it is sufficient to form a portion for engaging the retaining shaft portion 9b. Alternatively, a recess (engaging hole) for engaging the retaining shaft portion 9b can be formed on the inner surface of the housing portion 5 instead of the through hole 11.

Claims

1. A differential gear device, comprising: a housing member having a cylindrical receiving portion and being rotatably held about a central axis of the receiving portion; a pinion rotatably disposed and revolving about the central axis of the receiving portion inside the receiving portion; and two half-shaft gears disposed opposite to each other in the direction of the central axis of the receiving portion and meshing with the pinion, characterized in that... The pinion is equipped with: a solid gear portion consisting of bevel gears meshing with the two half-shaft gears; and a solid retaining shaft portion integrally formed with the gear portion and protruding towards the outer periphery of the receiving portion. The housing component has a fitting hole into which the retaining shaft is inserted.

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