Breather structure of gear device

Abstract

To provide a breather structure of a gear device capable of sufficiently utilizing an internal volume of a breather chamber.SOLUTION: In a breather structure of a gear device (speed reducer 2) according to the present invention, a first opening 341 is provided so as to open above a breather chamber 33. Consequently, compared to a case where the first opening 341 is formed as a horizontal hole that opens to the lateral side of the breather chamber 33, it is possible to make maximum use of an internal volume of the breather chamber 33, thereby increasing an effective volume of the breather chamber 33.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a breather structure for a gear device. [Background technology]

[0002] A known example of a conventional breather structure for a gear device is that described in Patent Document 1 below.

[0003] In brief, the breather structure of this gear device has a breather chamber for adjusting the internal pressure of the gear accommodating section, which is formed between a first housing provided at the axial end of the motor and a second housing joined to the first housing. The breather chamber is open to the atmosphere via a through-hole opening to the side of the breather chamber, making it possible to adjust the internal pressure of the gear accommodating section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-316766 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the breather structure of the conventional gear device, the through-hole opens to the side of the breather chamber, which means that lubricating oil that has flowed into the breather chamber may leak out through the through-hole. Furthermore, because the through-hole opens to the side of the breather chamber, it is difficult to fully utilize the internal volume of the breather chamber, so there is still room for improvement.

[0006] Therefore, the present invention was devised in consideration of the technical problems with the breather structure of the conventional gear device, and aims to provide a breather structure for a gear device that can fully utilize the internal volume of the breather chamber. [Means for solving the problem]

[0007] In one aspect, the present invention provides a breather structure for a gear device connected to the output side of a motor, the breather structure comprising: a first housing provided at an axial end of the motor; a second housing joined to the first housing and forming a gear accommodating section between the first housing and the second housing; a gear rotatably accommodated inside the gear accommodating section and immersed in lubricating oil stored in the gear accommodating section; a breather chamber provided at an upper part of the gear accommodating section, which opens to the outside of the gear accommodating section and adjusts the internal pressure of the gear accommodating section; and a first opening which opens above the breather chamber. [Effects of the Invention]

[0008] According to the present invention, the first opening is formed by a vertical hole that opens upward in the breather chamber. This makes it possible to make the most of the internal volume of the breather chamber, compared to when the first opening is formed by a horizontal hole that opens to the side of the breather chamber, and increases the effective volume of the breather chamber. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a motor unit with a reducer, in which a gear device according to the present invention is attached to the output side end of a motor. [Figure 2] 4 is an enlarged front view of a main part of the first housing, showing an enlarged view of the breather chamber and its vicinity. FIG. [Figure 3] 4 is an enlarged rear view of a main part of the first housing, showing an enlarged view of the breather chamber and its vicinity. FIG. [Figure 4] 3 is an enlarged cross-sectional view of the vicinity of a first opening, taken along line AA in FIG. 2, of the motor unit with a reducer shown in FIG. 1. FIG. [Figure 5] 3 is an enlarged cross-sectional view of the vicinity of a second opening, taken along line BB in FIG. 2, of the motor unit with a reducer shown in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

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

[0011] (Gear device configuration) Figure 1 shows an oblique view of a motor unit MU with a reducer, in which a reducer 2 serving as a gear device according to the present invention is connected to the output end of a motor 1, with the left side of Figure 1 corresponding to the front of the vehicle and the right side of Figure 1 corresponding to the rear of the vehicle.

[0012] 1, for example, a motor unit MU with a reducer includes a known motor 1 and a reducer 2 connected to the tip of an output shaft (not shown) of the motor 1, which corresponds to the output end of the motor 1. In other words, the reducer 2 is disposed between the motor 1, which is the driving source for the electric vehicle, and the drive shaft (not shown) of the vehicle, and the reducer 2 reduces the rotation of the motor 1 and transmits it to the drive shaft (not shown).

[0013] The motor 1 includes a motor housing 11 that opens to the side of the reducer 2, and motor elements (not shown) that are housed inside the motor housing 11 and include, for example, a rotor, a stator, and an output shaft that rotates integrally with the rotor. The reducer 2 mainly includes a gear housing 3 and multiple gears, such as an input gear G1, an intermediate gear G2, and an output gear G3, that are housed inside the gear housing 3. The motor housing 11 and the gear housing 3 are fastened together by a predetermined fastening means, for example, bolts 4.

[0014] The gear housing 3 is configured by joining a first housing 31 and a second housing 32, which are divided in two in the left-right direction of the vehicle, with a predetermined fastening means, for example, bolts (not shown). The gear housing 3 has a gear accommodating section 30, which is a space for accommodating an input gear G1, an intermediate gear G2, and an output gear G3, formed between the first housing 31 and the second housing 32. Furthermore, lubricating oil (not shown) is stored inside the gear accommodating section 30, for example, to the extent that the output gear G3 is immersed, thereby lubricating the gears G1, G2, and G3 when they mesh.

[0015] The input gear G1 is fixed to an input shaft S1 that rotates integrally with an output shaft (not shown) of the motor 1, and rotates integrally with the input shaft S1 (see FIG. 3). The output gear G3 has an outer diameter larger than that of the input gear G1 and is fixed to an output shaft (not shown) that rotates integrally with a differential shaft of a vehicle (not shown), and rotates integrally with the output shaft. The intermediate gear G2 is disposed between the input gear G1 and the output gear G3, and includes a first intermediate gear G21 that meshes with the input gear G1 and a second intermediate gear G22 that meshes with the output gear G3, which are arranged in series in the axial direction and integrally with the input gear G1 and output gear G3 via the intermediate shaft S2, and transmits the rotation of the input gear G1 to the output gear G3 at a reduced speed (see FIG. 3).

[0016] (Breather structure) Fig. 2 shows an enlarged view of a main part of the first housing 21 as seen from the front, with an enlarged view of the breather chamber 23 and its vicinity. Fig. 3 shows an enlarged view of a main part of the first housing as seen from the rear, with an enlarged view of the breather chamber 23 and its vicinity. Fig. 4 shows an enlarged cross-sectional view of the first opening 341 and its vicinity, obtained by cutting the speed reducer-equipped motor unit MU shown in Fig. 1 along a cutting line corresponding to line AA in Fig. 2. Fig. 5 shows an enlarged cross-sectional view of the second opening 342 and its vicinity, taken along a cutting line corresponding to line BB in Fig. 2.

[0017] 2 and 4, a breather chamber 33 for releasing the internal pressure (internal pressure) of the gear accommodating portion 30 to the outside is provided inside the gear housing 3 and above the gear accommodating portion 30. The breather chamber 33 is a space formed by joining a first breather chamber forming portion 313 formed as a recess on the joining surface of the first housing 31 where the first housing 31 joins with the second housing 32, and a second breather chamber forming portion 323 formed as a recess on the joining surface of the second housing 32 where the second housing 32 joins with the first housing 31.

[0018] The breather chamber 33 has a bottom wall 330 that separates it from the gear housing 20. A first through-hole 331 provided at the front end side and a second through-hole 332 provided at the rear end side are formed in the bottom wall 330 and penetrate the bottom wall 330 along the vertical direction. That is, the breather chamber 33 is separated from the gear housing 30 by the bottom wall 330, and is in communication with the gear housing 30 by the first through-hole 331 and the second through-hole 332. The first through-hole 331 and the second through-hole 332 may be formed as an ellipse (long hole) in addition to a perfect circle. The bottom wall 330 is inclined downward toward the rear of the vehicle so that the second through-hole 332 side is slightly lower.

[0019] 2 and 4, the breather chamber 33 is configured to be able to communicate with the outside via a first opening 341, which is a vertical hole that opens to the top of the gear housing 3. That is, the first opening 341 penetrates the peripheral wall portion 314 of the first housing 31 that constitutes the upper wall of the breather chamber 33 along the vertical direction, and opens the breather chamber 33 to the atmosphere outside the first housing 31. Here, the first opening 341 only needs to be open above the breather chamber 33, and can be provided by penetrating the peripheral wall portion 314 obliquely upward, for example, and does not need to be formed along the vertical direction as in this embodiment.

[0020] Moreover, it is desirable that the first opening 341 be positioned so as to be biased toward one end in the vehicle longitudinal direction, particularly toward the rear end of the vehicle. By positioning the first opening 341 toward the one end in this manner, it is possible to reduce the extension amount of the shielding portion 35 (described later), thereby making it possible to maximize the internal volume of the breather chamber 33. Furthermore, by positioning the first opening 341 so as to be biased toward the rear end of the vehicle, the distance from the output gear G3 immersed in lubricating oil within the gear accommodating portion 30 is the farthest, making it possible to effectively suppress the inflow of lubricating oil into the first opening 341 due to the lubricating oil being scooped up as the output gear G3 rotates.

[0021] 2 and 5, the first housing 31 is provided with a second opening 342 that penetrates the first housing 31 in the direction of the rotation axis of the motor 1, outside the gear accommodating portion 30 and inside the motor-side flange surface 311 of the first housing 31. One end of this second opening 342 opens to a side surface of the first housing 31 facing the second housing 32, and the other end opens to the motor internal space MR, which is a closed space formed by the joining of the motor-side flange surface 311 of the first housing 31 and the reducer-side flange surface 111 of the motor housing 11. In this way, the second opening 342 does not open directly to the outside of the first housing 31, but opens to the motor internal space MR, which is the closed space, thereby preventing water from entering the breather chamber 33 from the outside through the second opening 342. The second opening 342 need only open to a closed space outside the gear accommodating section 30 that does not directly face the outside (for example, a closed space formed in the vehicle body not shown), and is not limited to the motor internal space MR exemplified in this embodiment.

[0022] Furthermore, it is desirable that the second opening 342 be disposed in the vertical direction, for example, above the reference water level W (see FIG. 3) of a submerged road test of a vehicle, that is, at any height position where water does not flow into the second opening 342 during the submerged road test. In this case, it is desirable that the second opening 342 be disposed in a position where the connecting pipe 5 (described later) can be routed without interfering with other harnesses, etc., routed around the outer periphery of the geared motor unit MU, such as above the geared motor unit MU; in this embodiment, the second opening 342 is disposed, for example, below the breather chamber 33. As a result, in this embodiment, it is possible to set the overall length of the connecting pipe 5 (hose 53, described later) to a relatively short distance while avoiding interference between the connecting pipe 5 and other harnesses, etc., routed above the geared motor unit MU.

[0023] 1 to 3, the first opening 341 and the second opening 342 are connected to each other via a cylindrical connecting pipe 5. The connecting pipe 5 includes a cylindrical first plug 51 made of a metallic material and press-fitted into the outer end of the first opening 341, a cylindrical second plug 52 made of a metallic material and press-fitted into the outer end of the second opening 342, and a hose 53 made of an easily elastically deformable material (e.g., a rubber material) and cylindrically formed, connecting the first plug 51 and the second plug 52. As described above, in this embodiment, the connecting pipe 5 is formed separately into the first plug 51, the second plug 52, and the hose 53. This ensures a stable and strong connection to the first opening 341 and the second opening 342 by the first plug 51 and the second plug 52 made of a metallic material, while allowing for flexible and bendable handling by the hose 53 made of an elastic material.

[0024] The first plug 51 is formed in a generally L-shape with a first plug bent portion 510 bent at a generally right angle. A first plug small diameter portion 511 formed at one end portion facing downward is press-fitted into the first opening 341, and a first plug medium diameter portion 512 formed at the other end portion facing rearward of the vehicle is inserted into one end portion 531 of the hose 53. Furthermore, as shown in FIG. 4 , for example, a first plug large diameter portion 513 having an outer diameter larger than those of the first plug small diameter portion 511 and the first plug medium diameter portion 512 is provided between the first plug small diameter portion 511 and the first plug medium diameter portion 512 in a stepped manner. The first plug large diameter portion 513 is provided at a base end of the first plug small diameter portion 511 closer to the first plug small diameter portion 511 than the first plug bent portion 510, and regulates the amount of press-fitting of the first plug 51 into the first opening 341.

[0025] The second plug 52 is formed in a generally L-shape with a second plug bent portion 520 bent at a generally right angle. A second plug small diameter portion 521 formed at one end facing the motor 1 is press-fitted into the second opening 342, and a second plug medium diameter portion 522 formed at the other end facing upward is press-fitted into the other end 532 of the hose 53. Between the second plug small diameter portion 521 and the second plug medium diameter portion 522, as shown in FIG. 5 , for example, a second plug large diameter portion 523 having an outer diameter larger than the outer diameters of the second plug small diameter portion 521 and the second plug medium diameter portion 522 is provided in a stepped manner. The second plug large diameter portion 523 is provided at a base end of the second plug small diameter portion 521 closer to the second plug small diameter portion 521 than the second plug bent portion 520, and regulates the amount of press-fitting of the second plug 52 into the second opening 342.

[0026] Furthermore, inside the breather chamber 33, a shielding portion 35 is provided above the bottom wall 330 and at a position facing the first opening 341 in the vertical direction, which can block the lubricating oil that has entered the breather chamber 33 through the first through-hole 331 and the second through-hole 332 as the lubricating oil is scooped up by the rotation of the gears G1, G2, G3 from flowing into the first opening 341. This shielding portion 35 is formed by joining a first rib 315 provided in the first breather chamber component 313 of the first housing 31 and a second rib 325 provided in the second breather chamber component 323 of the second housing 32.

[0027] Moreover, it is desirable that the shielding portion 35 is provided so as to extend generally horizontally from the rear end of the breather chamber 33 in the vehicle longitudinal direction and to overlap the entire opening of the first opening 341 on the breather chamber 33 side in the vertical direction. In other words, the shielding portion 35 is provided only from the rear end of the breather chamber 33, which is the end closest to the first opening 341 in the vehicle longitudinal direction, to a position where it overlaps with the first opening 341. In this way, in this embodiment, the shielding portion 35 is provided only in the minimum range necessary to block the inflow of lubricating oil into the first opening 341, thereby enlarging the internal volume of the breather chamber 33 as much as possible.

[0028] (Effects of this embodiment) In the conventional gear device, a horizontal hole opening into the motor internal space MR is provided in the side wall of the breather chamber 33 on the motor 1 side, and the internal pressure of the gear accommodating portion 30 is adjusted via the horizontal hole. As a result, there is a risk that lubricating oil that has flowed into the breather chamber 33 will leak into the motor internal space MR via the horizontal hole. In addition, because the horizontal hole opens to the side of the breather chamber 33, it is difficult to fully utilize the internal volume of the breather chamber 33, and there is still room for improvement.

[0029] In contrast to this, in the breather structure of the gear device according to this embodiment, the first opening 341 is formed by a vertical hole that opens above the breather chamber 33. Therefore, compared to the breather structure of the conventional gear device in which the first opening 341 is formed by the horizontal hole that opens to the side of the breather chamber 33, it is possible to make maximum use of the internal volume of the breather chamber 33, and the effective volume of the breather chamber 33 can be increased.

[0030] In addition, in this embodiment, a second opening 342 for opening to the atmosphere is provided separately from the first opening 341, and the first opening 341 and the second opening 342 are connected by the connecting pipe 5. In this way, by providing the second opening 342 for opening to the atmosphere separately from the first opening 341, it is possible to suppress water from entering the gear accommodating portion 30 regardless of the arrangement (layout) of the breather chamber 33, and the degree of freedom in the layout of the breather chamber 33 can be improved.

[0031] In addition, in this embodiment, the second opening 342 for venting to the atmosphere is provided at a position lower than the first opening 341 that opens to the breather chamber 33. In this way, by arranging the second opening 342 below the breather chamber 33 that is located relatively higher within the gear accommodating section 30, it is possible to avoid a problem in which the connecting pipe 5 interferes with, for example, a motor harness (not shown) that is routed above the reducer 2, and the degree of freedom in handling the connecting pipe 5 can be improved.

[0032] In this embodiment, the first plug 51 is inserted into the first opening 341, and the second plug 52 is inserted into the second opening 342, and the first plug 51 and the second plug 52 are connected by a hose 53 made of an elastic rubber material. In this way, the intermediate portion of the connecting pipe 5 is formed by the hose 53 so as to be easily elastically deformed, which further improves the degree of freedom in handling the connecting pipe 5 compared to when the entire connecting pipe 5 is formed from a hard material such as a metal material. In addition, because the hose 53 connecting the first plug 51 and the second plug 52 is formed so as to be easily elastically deformed, the operation of connecting the hose 53 to the first plug 51 and the second plug 52 can be performed relatively easily.

[0033] In this embodiment, a shielding portion 35 capable of blocking lubricating oil that is scooped up with the rotation of the gears G1, G2, and G3 and flows into the breather chamber 33 is provided at a position facing the first opening 341 in the breather chamber 33. Therefore, the lubricating oil that is scooped up with the rotation of the gears G1, G2, and G3 and flows into the breather chamber 33 can be blocked by the shielding portion 35, and leakage of the lubricating oil through the first opening 341 into the motor internal space MR can be suppressed.

[0034] The present invention is not limited to the configurations exemplified in the above-described embodiments, but can be freely modified according to, for example, the specifications of the gear device to which the present invention is applied.

[0035] In particular, in the breather structure of the gear device according to the present invention, it is sufficient that the breather chamber 33 is open to the atmosphere via the first opening 341, and it is not necessarily required that the breather chamber 33 be open to the atmosphere via the second opening 342 as illustrated in the above embodiment. When the breather chamber 33 is open to the atmosphere via only the first opening 341, it is preferable that the first opening 341 is not opened directly to the outside, but is opened to a predetermined closed space (such as a closed space formed in the vehicle body, not shown), for example, via the first plug 51 and the hose 53. [Explanation of symbols]

[0036] 1...Motor 2...Reduction gear (gear device) 3...Gear housing 30...Gear housing 31...1st Housing 32...Second housing 33...Breather chamber 341...First opening 342...Second opening 35...Shielding part 5...Connecting pipe 51...First plug 52...Second plug 53...Hose G1...input gear (gear) G2...Intermediate gear (gear) G3...Output gear (gear) MR: Motor internal space (closed space) MU...Motor unit

Claims

1. A breather structure of a gear device connected to the output side of a motor, a first housing provided at an axial end of the motor; a second housing joined to the first housing to form a gear accommodating portion between the first housing and the second housing; a gear rotatably accommodated in the gear accommodating portion and immersed in lubricating oil stored in the gear accommodating portion; a breather chamber provided in an upper portion of the gear accommodating portion, the breather chamber being open to the outside of the gear accommodating portion and regulating the internal pressure of the gear accommodating portion; a first opening portion that opens upward to the breather chamber; A breather structure for a gear device comprising:

2. 2. The breather structure of claim 1, a second opening provided in the first housing and opening into a closed space formed between the first housing and the motor; a connecting pipe connecting the first opening and the second opening; A breather structure for a gear device comprising:

3. The breather structure of a gear device according to claim 2, A breather structure for a gear device, wherein the second opening is located lower than the first opening.

4. The breather structure of a gear device according to claim 2, A cylindrical first plug is press-fitted into the first opening, A cylindrical second plug is press-fitted into the second opening, The connecting pipe is formed of a hose made of an elastically deformable material, one end of which is inserted into the first plug and the other end of which is inserted into the second plug.

5. The breather structure of the gear device according to any one of claims 1 to 4, A breather structure for a gear device, comprising: a shielding portion, at a position facing the first opening in the breather chamber, capable of shielding the lubricating oil scooped up by rotation of the gear.

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