Lubrication structure of the transmission

Abstract

To lubricate a first speed gear G1 by using the motion energy of a lubricant which speedily moves to the rear of a vehicle upon abrupt acceleration in a first speed stage.SOLUTION: In a manual transmission mounted to a vehicle such that a counter shaft 1 is arranged along the vehicle fore- and -aft direction, a baffle plate 2 for temporarily storing a lubricant is arranged below the counter shaft 1. A shield plate 11 having an oil sump part 15, a slope part 17 and a gutter part 16 is attached to a center part of the baffle plate 2 in the longitudinal direction. The oil sump part 15 is located at the vehicle front side of a first speed gear G1, and the gutter part 16 surrounds the lower half part of the first speed gear G1. The slope part 17 extends obliquely upward to the gutter part 16 from the oil sump part 15. As a result of the lubricant speedily moving to the rear of the vehicle upon abrupt acceleration, it runs up along the slope part 17, jumps toward the first speed gear G1, and thus lubricates the first speed gear G1.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] This invention relates to a lubrication structure of a transmission mounted longitudinally in a vehicle, and particularly to a lubrication structure for reliably lubricating a specific gear during rapid acceleration.

Background Art

[0002] For example, in a transmission in which the axial direction of the rotating shaft is along the longitudinal direction of the vehicle, such as a manual transmission in a FR (front engine - rear drive) type automobile, during rapid acceleration of the vehicle, the lubricating oil stored at the bottom of the transmission housing moves rearward of the vehicle due to acceleration (so - called acceleration G), resulting in uneven distribution of the lubricating oil. Therefore, a phenomenon occurs where, for example, the gears of the countershaft that are normally partially immersed in the lubricating oil are temporarily exposed from the oil level.

[0003] Patent Document 1 discloses a lubrication structure of a transmission that provides a baffle plate at the lower part of the transmission housing and two dam plates respectively positioned before and after the gear at the foremost end of the countershaft at the front part of this baffle plate. This is a solution to the uneven distribution of lubricating oil during uphill driving. By blocking the lubricating oil that tends to move relatively downward when the transmission tilts during uphill driving, it suppresses the exposure of the gear at the foremost end.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The configuration described in Patent Document 1 merely dams up the lubricating oil and does not actively utilize the movement of the lubricating oil for gear lubrication. For example, during rapid acceleration of the vehicle, if a large amount of lubricating oil does not remain in the compartment separated by the two damming plates, the uneven distribution of lubricating oil within the compartment will cause the gears to be exposed, thus limiting its effectiveness. [Means for solving the problem]

[0006] This invention relates to a lubrication structure for a transmission in which a shaft equipped with multiple gears, each constituting a gear stage, is housed within a transmission housing, a baffle plate for temporarily accumulating lubricating oil is provided below the shaft, and the shaft is mounted in a vehicle so as to be aligned with the longitudinal direction of the vehicle. The above baffle plate comprises a baffle plate body and a shielding plate that is placed on top of the inside of the baffle plate body. The shielding plate comprises an oil reservoir located on the front side of a specific gear and extending in the longitudinal direction of the vehicle, a slope extending diagonally upward from the oil reservoir toward the specific gear, and a trough extending from the tip of the slope and covering the area below the specific gear. The oil reservoir section described above is roughly semi-cylindrical in shape, almost aligned with the concentric circle of the shaft, and its leading edge on the front side of the vehicle is open towards the front. The above-mentioned trough section has a roughly semi-cylindrical shape with a smaller radius than the above-mentioned oil reservoir section. The slope section described above has a shape that follows a conical surface, seamlessly continuing from the rear end of the oil reservoir section and seamlessly continuing from the front end of the trough section. Here, the specific gear mentioned above is the first gear. The oil reservoir mentioned above is located below the second gear, adjacent to the first gear on the front side of the vehicle.

[0007] During rapid acceleration of a vehicle, the lubricating oil stored at the bottom of the transmission housing attempts to move relatively quickly backward due to the acceleration. At least a portion of this rapidly moving backward lubricating oil is guided from the oil reservoir to the ramp section, where it jumps along the slope. In other words, it flows against gravity, rushing up the ramp section and splashing towards the specific gear being lubricated. This ensures that the target gear is reliably lubricated. [Effects of the Invention]

[0008] According to this invention, the kinetic energy of the lubricating oil during rapid acceleration is used to guide the lubricating oil upward, ensuring that the lubricating oil is reliably supplied to a specific gear located above the bottom of the transmission housing. [Brief explanation of the drawing]

[0009] [Figure 1] A perspective view showing a baffle plate in one embodiment together with a countershaft. [Figure 2] Plan view of the baffle plate and countershaft. [Figure 3] Cross-sectional view along line AA in Figure 2. [Figure 4] Cross-sectional view along line BB in Figure 2. [Figure 5] Perspective view of the baffle plate. [Figure 6] Perspective view of the baffle plate body. [Figure 7] Perspective view of the shielding plate. [Figure 8] An explanatory diagram showing the flow of lubricating oil during rapid acceleration. [Modes for carrying out the invention]

[0010] Hereinafter, an embodiment of this invention applied to a manual transmission for a front-engine, rear-wheel-drive (FR) automobile will be described with reference to the drawings. The manual transmission of this embodiment has a general configuration in which parallel main shafts (input shaft and output shaft) and a countershaft are housed in a transmission housing, with the countershaft positioned relatively lower, and lubricating oil is stored at the bottom of the transmission housing so that a portion of the lower countershaft is submerged in the oil. The main shaft and countershaft are equipped with a plurality of gears that constitute each gear stage, and the gears on the main shaft side and the gears on the countershaft side are constantly meshing with each other. Basically, each gear is lubricated by the fact that a portion of the outer circumference of each gear on the countershaft is submerged in the lubricating oil stored at the bottom of the transmission housing.

[0011] Figure 1 is a perspective view showing the countershaft 1 and the baffle plate 2 provided below it. The baffle plate 2 is provided along the bottom surface (inner surface) of a transmission housing (not shown) to temporarily accumulate lubricating oil around the countershaft 1 when climbing a slope, etc. It is generally trough-shaped with a circular arc cross-section concentric with the countershaft 1 and is made of a metal plate, for example, a pressed steel plate. In one embodiment, the baffle plate 2 is provided with two partition plates 8 and 9 at one end facing the front of the vehicle, aligned in a direction perpendicular to the axial direction, in order to appropriately restrict the movement of lubricating oil along the axial direction of the countershaft 1.

[0012] The countershaft 1 is equipped with gears for, for example, 1st to 6th gear and reverse, but in Figure 1, for the sake of simplicity, only the 1st gear G1, 2nd gear G2, and 3rd gear G3 are shown, and in particular, each gear is shown as a simple disc or cylindrical shape with the gear teeth omitted. The transmission is mounted on the vehicle so that the countershaft 1 is aligned with the vehicle's longitudinal direction, and in this mounted state, the 2nd gear G2 is located on the vehicle's front side of the 1st gear G1. Further forward of the 2nd gear G2 are the 6th gear and 5th gear, which are not shown. The 6th gear is located between the two partition plates 8 and 9 of the baffle plate 2, and the 5th gear is located on the vehicle's front side of partition plate 9. The 3rd gear G3 is located on the vehicle's rear side of the 1st gear G1. Further rear of the 3rd gear G3 is the 4th gear, which is not shown. Among these gears in countershaft 1, the first gear G1 has the smallest diameter.

[0013] As shown in Figure 1, a synthetic resin oil girder 3 is attached to one side edge of the baffle plate 2, forming an oil passage that collects the lubricating oil drawn up as the countershaft 1 gears rotate and supplies it to the outer surface of the gears. The oil girder 3 is not a key part of the present invention and will not be described in detail, but it mainly collects the lubricating oil drawn up by the 3rd gear G3 and 4th gear (not shown) in an oil receiving section 4 that opens upward toward the rear of the vehicle, and supplies lubricating oil to each gear from oil outlets 5, 6, and 7 provided at three locations in the front-rear direction of the vehicle. Lubricating oil is led from oil outlet 5 to the 1st gear G1, from oil outlet 6 to the 2nd gear G2, and from oil outlet 7 to the 6th gear and 5th gear (not shown). Furthermore, the baffle plate 2 is provided with multiple openings 10 (see Figure 5) near the parts corresponding to the 3rd gear G3 and 4th gear, so that lubricating oil can return from the underside (in other words, the outside) of the baffle plate 2 to the inside of the baffle plate 2.

[0014] Figure 2 is a plan view of the countershaft 1 and the baffle plate 2. In this Figure 2, the oil gutter 3 is not shown. Figure 3 is a longitudinal sectional view taken along the line A-A of Figure 2, and Figure 4 is a cross-sectional view taken along the line B-B of Figure 2. As shown in Figures 2 and 3, the baffle plate 2 is configured such that the part on the rear side of the vehicle corresponding to the 3-speed gear G3 and the 4-speed gear is wider and slightly lower downward than the part on the front side of the vehicle.

[0015] The line O / L in Figure 3 indicates the oil level position of the lubricating oil in the transmission housing in the vehicle stopped state. The oil level O / L is set above the axial center of the countershaft 1. Although the meshing portions between the gears on the countershaft 1 side and the gears on the main shaft side do not submerge in the oil, the oil level position O / L is set such that at least the lower half of each gear on the countershaft 1 side submerges in the oil.

[0016] Next, the shielding plate 11 which is the main part of the present invention will be described with reference to Figures 5 to 7. As shown in Figure 5, a shielding plate 11 made of a press-formed product of a metal plate, for example, a steel plate, is provided at the longitudinal center of the baffle plate 2 corresponding to the positions of the 1-speed gear G1 and the 2-speed gear G2. That is, in the illustrated example, the baffle plate 2 is composed of a baffle plate main body 2A shown in Figure 6 and a shielding plate 11 attached by overlapping inside the bottom surface of this baffle plate main body 2A. Specifically, the shielding plate 11 has two recesses 12 recessed in a trapezoidal shape for spot welding, and the bottom walls of these recesses 12 are overlapped with the top surfaces of two disk-shaped convex portions 13 provided on the baffle plate main body 2A and spot welded to each other.

[0017] As shown in Figures 6 and 5, the shielding plate 11 comprises an oil reservoir 15 which is substantially semi-cylindrical and substantially aligned with the concentric circle of the counter shaft 1, a trough 16 which has a smaller radius than the oil reservoir 15 and is substantially semi-cylindrical and substantially aligned with the concentric circle of the counter shaft 1, and a slope 17 connecting the oil reservoir 15 and the trough 16. The slope 17 extends in a tapered shape from the oil reservoir 15 toward the trough 16. In other words, the slope 17 has a shape that follows a concentric cone surface of the counter shaft 1.

[0018] Furthermore, a bent flange 18 is provided at the arc-shaped tip of the gutter section 16 on the rear side of the vehicle, rising inward at a constant width.

[0019] When the shielding plate 11 is assembled with the countershaft 1, as shown in Figures 1 to 3, the oil reservoir 15 is located below the second gear G2 and surrounds the lower half of the outer surface (tip circle) of the second gear G2. The trough 16 is located below the first gear G1, which is located further rearward than the second gear G2, and surrounds the lower half of the outer surface (tip circle) of the first gear G1. The slope 17 is located between the second gear G2 and the first gear G1 and has a shape that gradually converges from the second gear G2 towards the first gear G1.

[0020] As shown in Figure 3, the oil reservoir 15 extends from the central slope 17 toward the front of the vehicle, and its leading edge 15a is located above the bottom surface of the baffle plate body 2A. A relatively large gap is provided between it and the outer surface of the second gear G2 to allow lubricating oil to flow in from the front of the vehicle. In the illustrated example, the oil reservoir 15 has a slight tapered shape with the leading edge 15a slightly widened.

[0021] As shown in Figure 3, one end 16a of the trough section 16, which forms the boundary with the slope section 17, is located near the vehicle-front end face of the first gear G1, and the other end, the bent flange 18, is located near the vehicle-rear end face of the first gear G1 and overlaps with the outer circumferential surface of the first gear G1 in the axial direction. The distance between the trough section 16 and the outer circumferential surface of the first gear G1 is set to be smaller than the distance between the oil reservoir section 15 and the outer circumferential surface of the second gear G2, and the trough section 16 covers the lower half of the outer circumferential surface of the first gear G1 at a position relatively close to the first gear G1. The bent flange 18 is aligned with a plane perpendicular to the central axis of the countershaft 1 and rises toward the outer circumferential surface of the first gear G1. As shown in Figure 4, the bent flange 18 surrounds the lower half of the outer circumferential surface of the first gear G1 in a semicircular shape.

[0022] Furthermore, in the longitudinal cross-section shown in Figure 3, the slope section 17 extends linearly diagonally upward from the rear end of the oil reservoir section 15 toward the rear of the vehicle. The extension of this linearly extending slope section 17 intersects the outer circumferential surface of the first gear G1, that is, the cylindrical surface along the tooth tip circle. Also, in a plan view, as is clear from Figure 2, the width dimension gradually decreases as it moves toward the rear of the vehicle.

[0023] The shielding plate 11 described above contributes to ensuring reliable lubrication of the first gear G1 (and its meshing portion) in particular during rapid acceleration using the first gear. That is, during rapid acceleration of the vehicle, the lubricating oil stored at the bottom of the transmission housing attempts to move towards the rear of the vehicle at a relatively high speed due to the acceleration. At this time, some of the lubricating oil that was relatively close to the front of the transmission housing enters the inside of the oil reservoir 15 from the tip edge 15a that opens toward the front of the vehicle, and as a result flows at high speed along the slope portion 17, it jumps up the slope portion 17 toward the first gear G1, as shown by the arrow in the explanatory diagram of Figure 8, and collides with the first gear G1, especially its outer surface. Therefore, the teeth of the first gear G used during acceleration, and consequently the meshing portion with the first gear on the main shaft side, are reliably lubricated.

[0024] The first gear G on the countershaft 1 is small in diameter and tends to be far from the bottom surface of the transmission housing. However, as described above, by utilizing the kinetic energy of the lubricating oil via the slope portion 17, the first gear G, which is located at a relatively high position, can be reliably lubricated.

[0025] Furthermore, as is clear from Figure 2 in the plan view, the lubricating oil captured in the oil reservoir 15 is concentrated and guided to the first gear G.

[0026] Furthermore, in the above embodiment, since the trough portion 16 surrounds the lower half of the outer circumferential surface of the first gear G, the lubricating oil that flows backward via the slope portion 17 is more reliably retained near the outer circumferential surface of the first gear G. Moreover, the lubricating oil moving backward is blocked by the bent flange 18 and directed towards the inner circumference, so that more lubricating oil is guided to the outer circumferential surface of the first gear G.

[0027] In the illustrated example, as shown in Figure 4, the lubricating oil supplied from the oil outlet 5 of the oil gutter 3 toward the first gear G1 flows into the gutter 16.

[0028] As described above, in this embodiment, by providing a shielding plate 11 at the bottom of the baffle plate 2, the first gear G1 (and its meshing portion), which experiences the highest load during rapid acceleration using the first gear, can be reliably and efficiently lubricated.

[0029] In the above embodiment, the 1st gear G1, which is often used during rapid acceleration, is selected as the lubrication target by the slope section 17. However, other gears in the transmission stages, such as the 2nd gear G2, may also be selected as the lubrication target.

[0030] Alternatively, the baffle plate 2 may be provided with multiple, for example, two, slope sections to supply lubricating oil to multiple gears during rapid acceleration.

[0031] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various modifications are possible. For example, the "shaft" in the claim is not limited to a countershaft as in the above embodiment, but may be other shafts. Also, for example, the configuration may be such that the three axes of the input shaft, out shaft and countershaft are arranged in parallel, and the gear shifting, that is, the switching of the meshing gears, may be performed via an actuator. Furthermore, the slope portion may be a simple flat plate shape instead of a cone shape. [Explanation of symbols]

[0032] 1…Countershaft 2… Baffle plate 2A...Baffle plate body 3… Oil garter 11...Shielding plate 15…Oil reservoir 16…Hibe 17…Slope section 18...Bent flange G1...1st gear G2...2nd gear

Claims

1. In a transmission lubrication structure in which a shaft equipped with multiple gears, each constituting a gear stage, is housed within the transmission housing, and a baffle plate for temporarily accumulating lubricating oil is provided below the shaft, and the shaft is mounted in a vehicle so as to be aligned with the longitudinal direction of the vehicle, The above baffle plate comprises a baffle plate body and a shielding plate that is placed on top of the inside of the baffle plate body. The shielding plate comprises an oil reservoir located on the front side of a specific gear and extending in the longitudinal direction of the vehicle, a slope extending diagonally upward from the oil reservoir toward the specific gear, and a trough extending from the tip of the slope and covering the area below the specific gear. The oil reservoir section described above is roughly semi-cylindrical in shape, almost aligned with the concentric circle of the shaft, and its leading edge on the front side of the vehicle is open towards the front. The above-mentioned trough section has a roughly semi-cylindrical shape with a smaller radius than the above-mentioned oil reservoir section. The above-mentioned slope section has a shape that follows a conical surface, which is continuous without step at the rear end of the oil reservoir section and continuous without step at the front end of the trough section. Here, the specific gear mentioned above is the first gear. The above oil reservoir is located below the second gear, adjacent to the first gear on the front side of the vehicle. Lubrication structure of the transmission.

2. The above-mentioned slope portion extends in a straight line in a cross-section along the longitudinal direction of the vehicle, and its extension intersects the cylindrical tip surface of the tooth of the specific gear. Lubrication structure for a transmission according to claim 1.

3. The shaft mentioned above is the countershaft located at the bottom of the transmission housing. Lubrication structure for a transmission according to claim 1.

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