Gear case structure

Abstract

To provide a gear case structure which can sufficiently suppress the intrusion of a lubricant scooped up by the rotation of a first gear which is immersed into the lubricant into a breather part.SOLUTION: In a gear case of the present invention, a second block part 242 is provided so as to face a first intermediate gear 401 being a scoop-up source of a lubricant F. Therefore, the lubricant F scooped up from an output gear 30 via the first intermediate gear 401 can be directly blocked by the second block part 242 separately from a first block part 241 blocking a first penetration hole 231. By this constitution, it can be sufficiently suppressed that the lubricant F scooped up from the output gear 30 via the first intermediate gear 401 intrudes into a breather part 23 through the first penetration hole 231.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gear case structure. [Background technology]

[0002] A conventional gear case structure is known, for example, from Patent Document 1 below.

[0003] In brief, this gear case structure has a shielding portion at the lower part of the bottom wall of the breather portion, which faces the through hole penetrating the bottom wall. That is, this shielding portion prevents the lubricating oil scooped up by the rotation of the first gear, which is the output gear, from entering the breather portion through the through hole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-028988 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional gear case structure, there was still room for improvement in that the shielding portion located on the lower part of the bottom wall of the breather portion alone was not enough to prevent the lubricating oil scooped up by the rotation of the first gear from entering the breather portion.

[0006] Therefore, the present invention has been devised in consideration of the technical problems of the conventional gear case structure, and aims to provide a gear case structure that can sufficiently suppress the intrusion of lubricating oil scooped up by the rotation of the first gear immersed in lubricating oil into the breather section. [Means for solving the problem]

[0007] In one aspect of the present invention, a first shielding portion is provided below a through hole penetrating a bottom wall of a breather portion, the first shielding portion facing the through hole, and a second shielding portion is provided above a second gear that meshes with a first gear immersed in lubricating oil, the second gear facing the second gear. Effect of the Invention

[0008] According to the present invention, the lubricating oil scooped up by the rotation of the second gear accompanying the rotation of the first gear is blocked by the second shielding portion, and the lubricating oil scooped up by the rotation of the first gear and the second gear can be sufficiently prevented from entering the breather portion through the through hole. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a plan view of a gear case showing a main portion of the gear case structure according to the present invention. [Diagram 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 4] 2 is a perspective view of the gear case shown in FIG. 1 as viewed obliquely from above. [Diagram 5] 5 is a cross-sectional view taken along line CC in FIG. 4. [Figure 6] FIG. 5 is a cross-sectional view taken along line DD in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a gear case structure according to the present invention will be described in detail with reference to the drawings. In the following embodiments, an example will be described in which the gear case structure according to the present invention is applied to a reducer of a motor that is a driving source for an electric vehicle.

[0011] FIG. 1 is a diagram showing a main part of the gear case structure according to the present invention, and shows a plan view of the gear case 2 of the reduction gear 1 with the second casing 22, the second intermediate gear 402, and the input gear 50 omitted, with the left side of FIG. 1 corresponding to the front of the vehicle and the right side of FIG. 1 corresponding to the rear of the vehicle. FIG. 2 shows a cross-sectional view of the gear case 2 cut along the line AA shown in FIG. 1. FIG. 3 shows a cross-sectional view cut along the line BB shown in FIG. 1. FIG. 4 shows a perspective view of the gear case 2 shown in FIG. 1 as seen obliquely from above. FIG. 5 shows a cross-sectional view cut along the line CC shown in FIG. 4. FIG. 6 shows a cross-sectional view cut along the line DD shown in FIG. 4.

[0012] 1 is mounted on, for example, an electric vehicle, and is disposed between a motor (not shown) that is a drive source for driving the electric vehicle, and a drive shaft (not shown). Specifically, the reducer 1 mainly includes a gear case 2, an output shaft 3 that is a first shaft of the present invention and corresponds to a differential shaft, an intermediate shaft 4 that is a second shaft of the present invention, and an input shaft 5 that is a third shaft of the present invention and corresponds to a main shaft connected to the motor (not shown).

[0013] As shown in Fig. 2 and Fig. 3, the gear case 2 is configured by connecting a first casing 21 and a second casing 22, which are divided into two in the left-right direction of the vehicle, by a predetermined fastening means, for example, bolts BT. Between the first casing 21 and the second casing 22, the gear case 2 has a gear accommodating section 20, which is a space for accommodating an output gear 30, a first intermediate gear 401, a second intermediate gear 402, and an input gear 50, which will be described later. As shown in Fig. 1, the gear accommodating section 20 stores lubricating oil F to the extent that the output gear 30, which will be described later, is immersed in the lubricating oil F. The imaginary line shown in Fig. 1 indicates the oil level of the lubricating oil F, and the oil level of the lubricating oil F is set at a position slightly below the output shaft 3.

[0014] 1, the output shaft 3 is disposed at the lowermost position and the frontmost position with respect to the intermediate shaft 4 and the input shaft 5, and an output gear 30 corresponding to a first gear that rotates integrally with the output shaft 3 is provided on the outer circumferential side of the output shaft 3. The output shaft 3 is configured inside the gear case 2 as two separate parts, left and right, which are connected to each other via a differential gear (not shown) disposed between them. In addition, left and right drive shafts (not shown) are connected to both ends of the output shaft 3, and the output shaft 3 is connected to left and right drive wheels (not shown) via the drive shafts.

[0015] As shown in FIG. 1, the intermediate shaft 4 is disposed between the output shaft 3 and the input shaft 5, and is disposed above the output shaft 3 and at approximately the same height as the input shaft 5. As shown in FIGS. 1 to 3, a first intermediate gear 401 corresponding to a second gear meshing with the output gear 30 and rotating integrally with the intermediate shaft 4, and a second intermediate gear 402 corresponding to a fourth gear meshing with the input gear 50 described later and rotating integrally with the intermediate shaft 4 are provided at positions shifted in the axial direction on the outer circumferential side of the intermediate shaft 4. As shown in FIGS. 2 and 3, the intermediate shaft 4 is rotatably supported by a pair of bearings, a first bearing B1 and a second bearing B2, at both ends in the axial direction, specifically, at the axial outer positions of the first intermediate gear 401 and the second intermediate gear 402. In addition, a seal member SL that suppresses the outflow of the lubricating oil F stored in the gear accommodating portion 20 to the outside of the gear accommodating portion 20 is provided on the intermediate shaft 4 near the first end 41, which is axially outer than the first bearing B1.

[0016] 1 and 3, the input shaft 5 is disposed at approximately the same height as the intermediate shaft 4 and further rearward than the intermediate shaft 4, and an input gear 50 corresponding to a third gear that meshes with the second intermediate gear 402 and rotates integrally with the input shaft 5 is provided on the outer circumferential side of the input shaft 5. One axial end of the input shaft 5 is connected to the output shaft of the motor (not shown), and the rotational force of the motor (not shown) is transmitted from each drive shaft (not shown) to each drive wheel (not shown) via the input shaft 5, the input gear 50, the second intermediate gear 402, the intermediate shaft 4, the first intermediate gear 401, and the output shaft 3. Specifically, as shown in FIG. 1, the input shaft 5 rotates counterclockwise as indicated by arrow A1, the second intermediate gear 402 meshing with the input gear 50 rotates clockwise as indicated by arrow A2, and the output gear 30 meshing with the first intermediate gear 401 which rotates integrally with the second intermediate gear 402 rotates counterclockwise as indicated by arrow A3.

[0017] 1, the gear case 2 stores lubricating oil F to the extent that approximately half of the output gear 30 is immersed, and therefore, when the rotation of the input shaft 5 is transmitted to the output shaft 3, the lubricating oil F is scooped up by the rotation of the output gear 30 accompanying the rotation of the output shaft 3. Then, the lubricating oil F adhering to the output gear 30 adheres to the first intermediate gear 401 that meshes with the output gear 30, and the lubricating oil F adhering to the first intermediate gear 401 is scattered in the radial direction of the first intermediate gear 401. Similarly, when the second intermediate gear 402 rotates in conjunction with the rotation of the intermediate shaft 4, the lubricating oil F scooped up by the output gear 30 adheres to the second intermediate gear 402, and the lubricating oil F adhering to the second intermediate gear 402 adheres to the input gear 50 which meshes with the second intermediate gear 402, causing the lubricating oil F adhering to the input gear 50 to splash in the radial direction of the input gear 50.

[0018] As shown in Figs. 1, 3 to 6, the gear case 2 has a breather portion 23 that releases the pressure (internal pressure) of the gear accommodating portion 20 to the outside at an upper portion of the gear case 2, specifically, vertically above the input shaft 5. As shown in Figs. 3, 5 and 6, the breather portion 23 is a space formed by joining the first casing 21 and the second casing 22. As shown in Fig. 4, the breather portion 23 communicates with the outside through a breather hole 233 that opens at the upper portion. As shown in Figs. 1, 4 to 6, the breather portion 23 has a bottom wall 230 that separates the breather portion 23 from the gear accommodating portion 20, and a first through hole 231 facing a first shielding portion 241 described later and a second through hole 232 facing the input shaft 5 are formed in the bottom wall 230 by penetrating them in the vertical direction. In this case, the first through hole 231 is set to an inner diameter D1 that is relatively larger than the inner diameter D2 of the second through hole 232 (see Figs. 4 to 6). The first through hole 231 and the second through hole 232 may be, for example, an ellipse (long hole) in addition to a perfect circle. The bottom wall 230 is inclined downward toward the rear of the vehicle so that the second through hole 232 side is slightly lower.

[0019] 1, a protrusion 230a is provided at a lower portion of the bottom wall 230 of the breather portion 23, facing the end portion of the first shielding portion 241 on the vehicle rear side and facing the input gear 50. The protrusion 230a is provided at the end portion of the first shielding portion 241 on the vehicle rear side so as to narrow or close the gap (gap S1 described later) between the bottom wall 230 and the first shielding portion 241, and has a function of guiding the lubricating oil F scattered from the input gear 50 to the outer periphery of the input gear 50 by colliding with the lubricating oil F.

[0020] 1, 2, 4, and 5, the first casing 21 has, on the inner wall 210 facing the second casing 22, a first shielding portion 241 arranged above the input gear 50 and facing the input gear 50, and a second shielding portion 242 arranged above the first intermediate gear 401 and facing the first intermediate gear 401, which are integrally formed in a so-called rib-like protrusion. Note that, although the present embodiment illustrates an example in which the first shielding portion 241 and the second shielding portion 242 are continuously and integrally formed, the first shielding portion 241 and the second shielding portion 242 may be formed separately and provided intermittently.

[0021] 1, the first shielding portion 241 is set to a length L1 that is greater than at least an inner diameter D1 of the first through hole 231 in the horizontal direction (vehicle front-rear direction). Also, as shown in FIGS. 4 and 5, the first shielding portion 241 protrudes from the inner wall 210 of the first casing 21 with a predetermined width W1 such that at least a portion of the first shielding portion 241 vertically overlaps with the first through hole 231 in the horizontal direction (vehicle left-right direction), and faces the first through hole 231 with a predetermined distance S1. Also, the first shielding portion 241 is inclined downward toward the rear of the vehicle so that the input shaft 5 side is slightly lower than the intermediate shaft 4 side.

[0022] 1, a first protrusion 241a protruding vertically downward is provided at the middle portion of the first shielding portion 241. This first protrusion 241a faces a second end 211b of the introduction groove 211 described later, and has a function of colliding with the lubricating oil F that is scatter|spattered toward the first shielding portion 241 side among the lubricating oil F scooped up from the output gear 30 via the first intermediate gear 401, and guiding the lubricating oil F that is splashed toward the first shielding portion 241 side to the introduction groove 211.

[0023] 1 and 2, the second shielding portion 242 protrudes from the inner wall 210 of the first casing 21 with a predetermined width W2 such that at least a portion (about one-third in this embodiment) of the second shielding portion 242 vertically overlaps with the first intermediate gear 401 in the horizontal direction (vehicle left-right direction), and faces the outer circumferential surface of the first intermediate gear 401 with a predetermined distance S2. Note that it is sufficient for the second shielding portion 242 to protrude to an extent that it overlaps with at least a portion of the first intermediate gear 401 in the vertical direction, and the amount of protrusion can be changed as desired depending on the degree to which the lubricating oil F is scooped up.

[0024] The second shielding portion 242 is curved in a generally arc shape along the circumferential direction of the first intermediate gear 401. Specifically, the second shielding portion 242 has a first circumferential end 242a, which is the end at the front of the vehicle, extending to a position where it collides with the lubricating oil F scooped up from the output gear 30 via the first intermediate gear 401. On the other hand, the second end 242b, which is the end at the rear of the vehicle of the second shielding portion 242, extends to the vehicle rear side of the vertical line X passing through the rotation center Q of the intermediate shaft 4, and is curved in a circular arc shape opposite to the first end 242a side to be smoothly connected to the first shielding portion 241.

[0025] 1 and 3, an introduction groove 211 is formed in the inner wall 210 of the first casing 21, which is formed in a generally linear shape along the radial direction with respect to the rotation center Q of the intermediate shaft 4 and is recessed in a cross-sectionally concave shape. A first longitudinal end 211a of the introduction groove 211, which is a radially inner end, opens to the first bearing B1 and the seal member SL, and a second longitudinal end 211b, which is a radially outer end, extends radially outward beyond a virtual line VL extending from the inner surface of the second shielding portion 242. Thus, the introduction groove 211 has a function of collecting the lubricating oil F that is shielded by the second shielding portion 242 out of the lubricating oil F scooped up from the output gear 30 via the first intermediate gear 401, and guiding it to the first bearing B1 and the seal member SL.

[0026] 3, the introduction groove 211 is formed such that the groove depth DG gradually increases from the second end 211b side toward the first end 211a side. The introduction groove 211 is provided such that the first end 211a faces the axial gap between the first bearing B1 and the seal member SL, and the lubricating oil F collected in the introduction groove 211 can be guided to the first bearing B1 and the seal member SL through this axial gap.

[0027] (Effects of this embodiment) In the case of the conventional gear case structure described above, there was still room for improvement in that it was difficult to adequately prevent the lubricating oil F, which was scooped up by the rotation of the output gear 30, which is the first gear, from entering the breather portion 23, using only the shielding portion located at the lower part of the bottom wall 230 of the breather portion 23.

[0028] In contrast, the gear case structure of this embodiment, in particular, has a first shielding portion 241 provided opposite the first through hole 231 of the breather portion 23, and a second shielding portion 242 provided opposite the first intermediate gear 401 corresponding to the second gear.

[0029] In this manner, in the gear case structure according to the present embodiment, the second shielding portion 242 is provided so as to face the first intermediate gear 401, which is the scoop-up source of the lubricating oil F, and therefore the lubricating oil F scooped up from the output gear 30 through the first intermediate gear 401 can be directly shielded by the second shielding portion 242, separately from the first shielding portion 241 that shields the first through hole 231. As a result, in addition to the first shielding portion 241, the second shielding portion 242 can also shield the scoop-up of the lubricating oil F from the output gear 30 and the first intermediate gear 401, and the intrusion of the lubricating oil F scooped up from the output gear 30 through the first intermediate gear 401 into the breather portion 23 through the first through hole 231 can be sufficiently suppressed.

[0030] As described above, the first shielding portion 241 and the second shielding portion 242 suppress the intrusion of the lubricating oil F into the breather portion 23 through the first through hole 231, so that the lubricating oil F scooped up or splashed up by the input gear 50 enters the breather portion 23 through the second through hole 232, and the lubricating oil F that has entered the breather portion 23 is discharged to the gear accommodating portion 20 through the first through hole 231, so that the flow of the lubricating oil F is one-way. Therefore, compared with the case where the lubricating oil F also enters through the first through hole 231, the lubricating oil F that has entered the breather portion 23 can be more smoothly discharged to the gear accommodating portion 20 through the first through hole 231. The scooping up of the lubricating oil F by the input gear 50 occurs when, for example, the lubricating oil F shifts and flows toward the input shaft 5 in the gear accommodating portion 20 during vehicle turning, and a part of the input gear 50 is immersed in the lubricating oil F. On the other hand, splashing of the lubricating oil F by the input gear 50 occurs when the lubricating oil F adhering to the input gear 50 via the first intermediate gear 401 or the second intermediate gear 402 is scattered by the rotation of the input gear 50.

[0031] In addition, in the gear case structure according to this embodiment, the first shielding portion 241 and the second shielding portion 242 are formed continuously and integrally. Therefore, the lubricating oil F scooped up from the output gear 30 through the first intermediate gear 401 can be effectively shielded by the series of the first shielding portion 241 and the second shielding portion. As a result, the lubricating oil F that cannot be completely shielded by the second shielding portion 242 can be shielded by the first shielding portion 241 that is continuous with the second shielding portion 242, and the lubricating oil F scooped up from the output gear 30 through the first intermediate gear 401 can be effectively prevented from entering the breather portion 23 through the first through hole 231.

[0032] Furthermore, in the gear case structure according to this embodiment, the second shielding portion 242 is formed in an arc shape along the circumferential direction of the first intermediate gear 401. This makes it possible to guide the lubricating oil F scooped up from the output gear 30 via the first intermediate gear 401 to the intermediate shaft 4 side (radially inward). This contributes to the lubrication of the first bearing B1 and the seal member SL that support the intermediate shaft 4.

[0033] In the gear case structure according to this embodiment, the first through hole 231 is set to an inner diameter D1 larger than the inner diameter D2 of the second through hole 232. As described above, according to this embodiment, the first shielding portion 241 and the second shielding portion 242 suppress the intrusion of the lubricating oil F into the breather portion 23 through the first through hole 231. Therefore, the first through hole 231 is formed larger than the second through hole 232 as a discharge hole for the lubricating oil F that has infiltrated into the breather portion 23 through the second through hole 232. This allows the lubricating oil F that has infiltrated into the breather portion 23 through the second through hole 232 to be effectively discharged through the first through hole 231.

[0034] In particular, since the inner diameter D1 of the first through hole 231 is formed relatively larger than the inner diameter D2 of the second through hole 232, not only can the lubricating oil F that has entered through the second through hole 232 in the fore-and-aft direction of the vehicle be effectively discharged to the gear accommodating portion 20 via the first through hole 231, but also, even if the lubricating oil F shifts and flows toward the first casing 21 side or the second casing 22 side within the breather portion 23, for example, when the vehicle turns, the lubricating oil F within the breather portion 23 can be effectively discharged to the gear accommodating portion 20 via the first through hole 231, which is relatively larger than the second through hole 232.

[0035] Furthermore, in the gear case structure according to this embodiment, the lubricating oil F scooped up from the output gear 30 through the first intermediate gear 401 is guided to the introduction groove 211 by the second shielding portion 242 curved along the circumferential direction of the first intermediate gear 401, and is guided through the introduction groove 211 to the first bearing B1 that supports the intermediate shaft 4 and the seal member SL that seals the intermediate shaft 4. This makes it possible to smoothly guide the lubricating oil F scooped up from the output gear 30 through the first intermediate gear 401 to the first bearing B1 and the seal member SL, and effectively lubricates the first bearing B1 and the seal member SL.

[0036] The present invention is not limited to the configuration exemplified in the above embodiment, and can be freely modified according to, for example, the specifications of the gear case structure to which the present invention is applied.

[0037] For example, in this embodiment, an example has been given of the gear case structure of the present invention being applied to a motor reducer 1 which is the driving source for an electric vehicle; however, in addition to the motor reducer 1, the gear case structure of the present invention can also be applied to gear case structures of other reducers, such as a reducer for a manual transmission. [Explanation of symbols]

[0038] 1...Reducer 2. Gear case 20...Gear housing 21…First casing (gear case) 210…Inner wall 211... Introduction groove 22...Second casing (gear case) 23…Breather section 230…Bottom wall 231...First through hole (through hole) 232...Second through hole 241...First shielding part 242...Second shielding part 3...Output shaft (first shaft) 30...Output gear (1st gear) 4...Intermediate shaft (second shaft) 401...1st intermediate gear (2nd gear) 402...2nd intermediate gear (4th gear) 5...Input shaft (3rd shaft) 50...Input gear (3rd gear) B1…First bearing (bearing) SL: Sealing material

Claims

1. a first gear that rotates integrally with the first shaft; a second gear that rotates integrally with the second shaft and meshes with the first gear; a gear accommodating portion that accommodates the first gear and the second gear together with lubricating oil therein and immerses the first gear in the lubricating oil therein; a breather portion disposed in an upper portion of the gear housing portion and serving to release pressure in the gear housing portion to the outside; a through hole provided at a position offset in a horizontal direction from the second gear and penetrating a bottom wall of the breather portion; A first shielding portion provided below the through hole and facing the through hole; a second shielding portion provided above the second gear and facing the second gear; A gear case structure comprising:

2. The gear case structure according to claim 1, The first shielding portion and the second shielding portion are formed continuously and integrally. A gear case structure characterized by the above.

3. The gear case structure according to claim 1 or 2, The second shielding portion is formed in an arc shape along the circumferential direction of the second gear. A gear case structure characterized by the above.

4. The gear case structure according to claim 1, a fourth gear that rotates integrally with the second shaft and is disposed in parallel with the second gear in the axial direction of the second shaft; a third shaft that rotates integrally with a third gear that meshes with the fourth gear; Further equipped with the through hole is provided in a plurality of spaces apart from each other, and includes a first through hole arranged on the second gear side and a second through hole arranged on the third gear side, The first through hole has a larger inner diameter than the second through hole. A gear case structure characterized by the above.

5. The gear case structure according to claim 3, The second shaft is rotatably supported via a bearing disposed in the gear accommodating portion, An introduction groove is provided on an inner wall of the gear accommodating portion on an outer circumferential side of the second gear to introduce the lubricating oil to the bearing, The lubricating oil scooped up by the rotation of the first gear and the second gear is introduced into the introduction groove via the second shielding portion. A gear case structure characterized by the above.

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