Gear mechanism

Abstract

In conventional gear mechanisms, which include pairs of gears with orthogonally arranged rotating shafts, it has been difficult to supply sufficient lubrication to the entire gear and bearing system. [Solution] The gear mechanism comprises a drive gear 4 fixed to the output shaft 3 of a motor 2, a driven gear 5 arranged parallel to the drive gear 4, a rotating gear 6 fixed on the axis of the driven gear 5, and a revolving gear 7 arranged perpendicular to the rotating gear 6, wherein lubricating oil is stored in the housing 1, and the rotating gear 6 and the revolving gear 7 are arranged so that their rotation axes are perpendicular to each other in the horizontal plane, and the driven gear has through holes 8 communicating in the axial direction at predetermined intervals around its axis. This configuration ensures that sufficient lubricating oil is supplied to the entire gear mechanism, including a pair of gears with rotation axes arranged perpendicularly to each other.

Description

Technical Field

[0001] The present invention relates to a gear mechanism, and more particularly to a gear mechanism suitable for a driving device of an automobile.

Background Art

[0002] As a conventional gear mechanism, for example, there is one described in Patent Document 1. Patent Document 1 describes a gear mechanism that transmits the rotation of a motor to a differential device and an axle in a vehicle. This gear mechanism arranges the motor in a posture where the rotation axis faces in the longitudinal direction of the vehicle, and includes a pinion that is rotationally driven by the motor and a hypoid gear whose rotation axis is arranged orthogonally to this pinion, thereby aiming to shorten the dimension in the vehicle width direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of the above-described conventional gear mechanism, that is, a gear mechanism including a pair of gears with orthogonal rotation axes, although it is relatively easy to supply lubricating oil to the gears, there is a problem that it is difficult to supply sufficient lubricating oil to the entire gears and bearings.

[0005] [[ID=�8]] The present invention has been made in view of the above conventional situation, and particularly aims to provide a gear mechanism that can supply sufficient lubricating oil to the whole in a gear mechanism including a pair of gears with orthogonal rotation axes, and can improve power transmission efficiency and cooling function.

Means for Solving the Problems

[0006] The gear mechanism according to the present invention comprises a drive gear fixed to the output shaft of a motor, a driven gear whose rotation axis is arranged parallel to the drive gear, a rotating gear fixed on the axis of the driven gear, and a revolving gear whose rotation axis is arranged perpendicular to the rotating gear, all housed in a housing. The mechanism transmits the rotation of the drive gear to the revolving gear via the driven gear and the rotating gear. The gear mechanism is characterized in that lubricating oil is stored in the housing, the rotating gear and the revolving gear are arranged so that their rotation axes are perpendicular to each other in the horizontal plane, and the driven gear has through holes communicating in the axial direction at predetermined intervals around its axis. [Effects of the Invention]

[0007] The gear mechanism according to the present invention includes a gear pair with orthogonally arranged rotating shafts, i.e., a rotating gear and a revolving gear, and can supply sufficient lubricating oil to the entire gear and bearing, thereby improving power transmission efficiency and cooling function. [Brief explanation of the drawing]

[0008] [Figure 1] (A) is a cross-sectional view of the main part showing the first embodiment of the gear mechanism, (B) is a perspective view illustrating the overall configuration of the gear mechanism, and (C) is an explanatory diagram showing the front and side views of the driven gear and the rotating gear. [Figure 2] These are perspective views (A) to (C) and a cross-sectional view (D) of the main part, showing four examples with different through-holes in the driven gear. [Figure 3] This is a cross-sectional view (A) and a cross-sectional explanatory view (B) with an enlarged view showing a second embodiment of the gear mechanism. [Figure 4] Figure 3 shows cross-sectional views (A) and (B) illustrating the flow of lubricating oil in the gear mechanism. [Modes for carrying out the invention]

[0009] <First Embodiment> The gear mechanism shown in Figure 1 comprises a drive gear 4 fixed to the output shaft 3 of the motor 2, a driven gear 5 whose rotation axis is parallel to the drive gear 4, a rotating gear 6 fixed on the axis of the driven gear 5, and a revolving gear 7 whose rotation axis is perpendicular to the rotating gear 6, all housed in a housing 1 partially shown in Figure 1(A). This gear mechanism transmits the rotation of the drive gear 4 to the revolving gear 7 via the driven gear 5 and the rotating gear 6. Note that Figure 1(B) shows the overall configuration of the gear mechanism, and details such as the holding portion of the rotating gear 6 differ from the configuration of the embodiment shown in Figure 1(A).

[0010] The gear mechanism described above constitutes the vehicle's drive system, with the output shaft 3 of the motor 2 oriented in the vehicle's longitudinal direction (left-right direction in Figure 1A), and the rotation axes of the rotation gear 6 and the revolution gear 7 being perpendicular in the horizontal plane, mounted on the vehicle. The rotation of the motor 2 is transmitted to the differential device and axle connected to the revolution gear 7.

[0011] The drive gear 4 and driven gear 5 of the gear mechanism described above are, for example, helical gears. The orbital gear 7 is, for example, a hypoid gear having an annular tooth arrangement, and the rotating gear 6 is a pinion gear that engages with this orbital gear 7. The rotating gear 6 has a shaft portion 6A that penetrates the center of the driven gear 5, and is fixed by press-fitting the shaft portion 6A into the central hole of the driven gear 5.

[0012] Furthermore, in the gear mechanism described above, the driven gear 5 has a concentric annular recess 5A on the opposite side of the revolving gear 7 (right side in Figure 1A), and a first bearing B1 is housed in the recess 5A, which rotatably holds the driven gear 5 relative to the housing 1. In addition, a second bearing B2 is positioned at the end of the shaft portion 6A that protrudes from the driven gear 5 on the opposite side of the revolving gear 7, which rotatably holds the shaft portion 6A relative to the housing 1. The first bearing B1 shown is a ball bearing. The second bearing B2 can be a ball bearing, a needle bearing, or the like.

[0013] In the gear mechanism described above, the second bearing B2 has a smaller diameter than the first bearing B1 and is positioned close to the driven gear 5. This reduces the axial dimension of the motor 2 and, in the case of a vehicle, reduces the longitudinal dimension of the vehicle.

[0014] Furthermore, as shown in Figure 1(C), the gear mechanism described above has a driven gear 5 with through holes 8 that communicate in the axial direction at predetermined intervals around its axis. In the illustrated example of the gear mechanism, multiple through holes 8 are arranged at equal intervals in the circumferential direction on the outer circumference of the rotating gear 6, which is fixed on the axis of the driven gear 5.

[0015] Furthermore, the above gear mechanism can employ a through hole 8 parallel to the rotation axis of the driven gear 5, as shown in Figure 2(A), a through hole 8 inclined with respect to the rotation axis of the driven gear 5, as shown in Figure 2(B), or a curved through hole 8, as shown in Figure 2(C). Moreover, as a more preferred embodiment, the above gear mechanism can employ a tapered through hole 8 in which the cross-sectional area gradually decreases from the side of the driven gear 5 on the revolving gear 7 side (left side in Figure 2) to the opposite side, as partially shown in Figure 2(D).

[0016] In the gear mechanism described above, the housing 1 houses the gear mechanism together with the motor 2, and a predetermined amount of lubricating oil is stored inside, as shown by the oil level OL in Figure 1(C). The amount of lubricating oil in the illustrated example is such that at least a portion of the lower part of the first bearing B1 is submerged.

[0017] The gear mechanism with the above configuration transmits the rotation of the motor 2 in the order of drive gear 4, driven gear 5, rotation gear 6, and revolution gear 7, and performs two-stage speed change in this rotation transmission. In this case, the gear mechanism scoops up lubricating oil with the revolution gear (hypoid gear) 7 and supplies the lubricating oil to the drive gear 4, driven gear 5 and rotation gear 6. Since the driven gear 5 has a through hole 8, lubricating oil is supplied to the back side of the driven gear 5 (opposite side of the revolution gear 7) through this through hole 8, and also to the first bearing B1 and the second bearing B2.

[0018] In this way, in the gear mechanism including a pair of gears with rotation axes arranged orthogonally, that is, the idler gear 6 and the orbiting gear 7, sufficient lubricating oil can be supplied to the entire gears and bearings, and the power transmission efficiency and cooling function can be improved.

[0019] Also, in the above-described gear mechanism, since the through hole 8 is arranged on the outer peripheral side of the idler gear 6 fixed to the driven gear 5, the lubricating oil flowing from the small-diameter portion to the large-diameter portion of the idler gear 6 due to centrifugal force can be quickly introduced into the through hole 8.

[0020] Furthermore, the above-described gear mechanism makes it easier to introduce the lubricating oil into the through hole 8 by inclining or curving the through hole with respect to the rotation axis of the driven gear 5, and by applying the thrust generated by the rotation of the driven gear 5 to the lubricating oil, the lubricating oil can be efficiently scattered on the back side of the driven gear 5, and the supply of the lubricating oil to the bearing can be further promoted.

[0021] Furthermore, the above-described gear mechanism can vigorously inject the lubricating oil between the first bearing B1 and the second bearing B2 by adopting the tapered through hole 8, due to the nozzle effect, and can contribute to further improvement of the lubrication performance and cooling performance.

[0022] Furthermore, as described above, the above-described gear mechanism can supply sufficient lubricating oil to the entire gears and bearings after realizing shortening of the axial dimension of the motor 2 and, in the case of a vehicle, shortening of the dimension in the vehicle front-rear direction, and can improve the power transmission efficiency and cooling function.

[0023] <Second Embodiment> FIG. 3 and FIG. 4 are diagrams for explaining a second embodiment of the gear mechanism according to the present invention. In the following embodiments, the same reference numerals are given to the same components as those in the first embodiment, and detailed description thereof is omitted.

[0024] The gear mechanism, whose main components are shown in Figure 3, has a configuration in which the rotating gear 6 has an extended tooth row 9 in the range leading to the shaft portion 6A, and the grooves of the extended portion 9 are open to the opposite side of the driven gear 5 from the revolving gear 7 (the right side in Figure 3A).

[0025] Furthermore, as shown in the enlarged view of the upper part of Figure 3(B), the gear mechanism described above has an upper flow path Fa formed between the housing 1 and the driven gear 5 and the rotating gear 6, which allows lubricating oil to flow from the first bearing B1 to the second bearing B2.

[0026] Furthermore, as shown in the enlarged view of the lower part of Figure 3(B), the gear mechanism described above has a lower passage Fb1 formed between the housing 1 and the driven gear 5 and the rotating gear 6, which allows lubricating oil to flow from the first bearing B1 to the second bearing B2. This lower passage Fb1 has a narrow section 10 near the first bearing B1 where the passage area is partially narrowed. The gear mechanism also has a second lower passage Fb2 formed which allows lubricating oil to flow from the outer peripheral space of the housing 1 and the driven gear 5 to the narrow section 10.

[0027] The gear mechanism having the above configuration, similar to the first embodiment, is a gear mechanism including a pair of gears (rotating gear 6 and revolving gear 7) with their rotating shafts arranged orthogonally, which provides sufficient lubrication to the entire gear and bearing, thereby improving power transmission efficiency and cooling function. Furthermore, the lubrication can reach the first bearing B1 more easily, resulting in further improvements in power transmission efficiency and cooling function.

[0028] Furthermore, by providing an upper flow path Fa in the gear mechanism described above, lubricating oil can be distributed more easily to both the first bearing B1 and the second bearing B2, thereby achieving further improvements in power transmission efficiency and cooling function.

[0029] Furthermore, the gear mechanism described above is provided with a lower flow path Fb1 and a second lower flow path Fb2. In the lower flow path Fb1, as shown by the thick arrow in Figure 4, lubricating oil flows from the first bearing B1 to the second bearing B2. In the second upper flow path Fb2, as shown by the thin arrow in Figure 4, lubricating oil flows from the inlet on the outer circumference side of the driven gear 5 to the outlet on the upper narrow section 10 side, and merges with the lower flow path Fb1. At this time, in the gear mechanism described above, the region of the narrow section 10 in the lower flow path Fb1 becomes a negative pressure due to the Venturi effect, drawing in the lubricating oil flowing through the second lower flow path Fb2.

[0030] As a result, the gear mechanism described above can further promote the supply of lubricating oil to both the first bearing B1 and the second bearing B2. This can lead to further improvements in power transmission efficiency and cooling function.

[0031] The gear mechanism according to the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit of the invention, such as the number and arrangement of through holes and the number of upper and lower flow paths. [Explanation of Symbols]

[0032] 1 Housing 2 motors 3 Output shaft 4 Drive gears 5 Driven gear 5A Recess 6. Rotating gear 6A shaft part 7. Orbital gear 8 Through holes 9 Extension 10 Narrow area B1 First bearing B2 Second bearing Fa Upper channel Fb1 lower flow path Fb2 Second lower channel

Claims

1. A gear mechanism comprising, within a housing, a drive gear fixed to the output shaft of a motor, a driven gear whose rotation axis is parallel to the drive gear, a rotating gear fixed on the axis of the driven gear, and a revolving gear whose rotation axis is perpendicular to the rotating gear, wherein the rotation of the drive gear is transmitted to the revolving gear via the driven gear and the rotating gear, The housing contains lubricating oil, and the rotating gear and the revolving gear are arranged so that their axes of rotation are perpendicular to each other in the horizontal plane. A gear mechanism characterized in that the driven gear has through holes communicating in the axial direction at predetermined intervals around the axis.

2. The gear mechanism according to claim 1, characterized in that the through hole of the driven gear is inclined with respect to the rotation axis of the driven gear.

3. The gear mechanism according to claim 1, characterized in that the cross-sectional area of ​​the through hole of the driven gear gradually decreases in the direction from the side of the driven gear facing the orbital gear to the opposite side.

4. The driven gear has a concentric annular recess on the opposite side of the revolving gear, and a first bearing is housed in the recess, which rotatably holds the driven gear relative to the housing. The aforementioned rotating gear has a shaft portion that penetrates the center of the driven gear, The gear mechanism according to claim 1, characterized in that a second bearing is arranged at the end of the shaft portion protruding from the driven gear, which rotatably holds the shaft portion relative to the housing.

5. The gear mechanism according to claim 4, characterized in that the rotating gear has an extended tooth row portion in the range leading to the shaft portion, and the valleys of the extended portion are open to the opposite side of the driven gear from the revolving gear.

6. The gear mechanism according to claim 4, characterized in that, above the rotating gear, an upper passage is formed between the housing, the driven gear and the rotating gear, for circulating the lubricating oil from the first bearing to the second bearing.

7. Below the rotating gear, a lower passage is formed between the housing, the driven gear, and the rotating gear, for circulating the lubricating oil from the first bearing to the second bearing, and the lower passage has a narrowed portion that partially reduces the flow area. The gear mechanism according to claim 4, characterized in that a second lower passage is formed in the housing for circulating the lubricating oil from the outer peripheral space of the driven gear to the narrow portion.

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