Clutch housing

Abstract

To provide a clutch housing that can further improve the cooling performance.SOLUTION: The peripheral wall of a clutch housing is formed with a second rib vertically above the rotation axis of a clutch and on an upstream side of a swirl flow with respect to a first rib, which has a predetermined protruding length in the radial direction shorter than that of the first rib. Deflection of the swirl flow on the upstream side of the first rib is therefore suppressed, and the swirl flow is properly deflected by the first rib, so that the swirl flow containing atmospheric air newly sucked through an inlet port can be efficiently applied to the whole clutch. As a result, frictional heat of the clutch is easily dissipated. Accordingly, the cooling performance in the clutch housing can be further improved.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a clutch housing that rotatably houses a clutch. [Background technology]

[0002] A well-known clutch housing has a cylindrical peripheral wall portion having a clutch chamber that rotatably houses a friction clutch that switches between transmission and interruption of power in a power transmission path between an output rotating member that outputs engine power and an input rotating member to which the engine power is input, and the peripheral wall portion is provided with an intake hole that draws air outside the peripheral wall portion into the clutch chamber by a swirling flow of air generated around the clutch as the clutch rotates, and an exhaust hole that exhausts air from the clutch chamber to the outside of the peripheral wall portion, the intake hole being provided in the peripheral wall portion vertically above the rotation axis of the clutch. For example, the clutch housing described in Patent Document 1 is such a clutch housing. Patent Document 1 discloses that a rib is formed in the peripheral wall portion at a position adjacent to the upstream side of the swirling flow with respect to the intake hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-62514 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in a friction clutch, frictional heat is generated by frictional engagement, and the clutch may become hot. Patent Document 1 discloses that the air swirling around the clutch removes the frictional heat of the clutch and is then discharged to the outside through a discharge hole, thereby cooling the clutch. It also discloses that a part of the air swirling around the clutch collides with a rib, generating a negative pressure near the downstream side of the rib in the direction of rotation, and this negative pressure makes it easier for the air to be drawn into the clutch chamber through the intake hole, improving the cooling performance. There is room for improvement in dissipating the frictional heat of the clutch, and it is desirable to further improve the cooling performance.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a clutch housing that can further improve cooling performance. [Means for solving the problem]

[0006] The gist of the first invention is that (a) a clutch housing including a cylindrical peripheral wall portion having a clutch chamber that rotatably houses a friction clutch that switches between transmission and interruption of power in a power transmission path between an output rotating member that outputs engine power and an input rotating member to which engine power is input, the peripheral wall portion being provided with an intake hole that draws air outside the peripheral wall portion into the clutch chamber by a swirling flow of air generated around the clutch as the clutch rotates, and a discharge hole that discharges air in the clutch chamber to the outside of the peripheral wall portion, the intake hole being provided in the peripheral wall portion vertically above a rotation axis of the clutch, and (b) a first rib is formed in the peripheral wall portion at a position adjacent to the upstream side of the swirling flow relative to the intake hole, and a second rib is formed vertically above the rotation axis of the clutch and upstream of the swirling flow relative to the first rib, the radial protruding length being a predetermined length shorter than that of the first rib. Effect of the Invention

[0007] According to the first invention, the peripheral wall of the clutch housing is formed with a first rib at a position adjacent to the upstream side of the swirling flow with respect to the suction hole, so that the swirling flow hits the first rib and is deflected, generating a negative pressure area near the downstream of the swirling flow of the first rib. This makes it easier for the air outside the peripheral wall to be drawn into the clutch chamber through the suction hole. In addition, the peripheral wall of the clutch housing is formed with a second rib, which has a predetermined radial protruding length shorter than that of the first rib, at a position vertically above the rotation axis of the clutch and upstream of the swirling flow with respect to the first rib. This suppresses deflection of the swirling flow upstream of the first rib, and the first rib appropriately deflects the swirling flow, so that the swirling flow including the air newly drawn through the suction hole can be efficiently applied to the entire clutch. This makes it easier for frictional heat of the clutch to be dissipated. This further improves the cooling performance of the clutch housing. [Brief description of the drawings]

[0008] [Figure 1] 1 is a partial cross-sectional view showing an example of a clutch and a release mechanism accommodated in a clutch housing to which the present invention is applied. [Diagram 2] FIG. 2 is a diagram showing an example of a front view of a clutch housing as viewed from the engine side. [Diagram 3] FIG. 4 is a diagram showing an example of an oblique side view of the clutch housing as viewed from the mounting hole side. [Figure 4] 4A and 4B are diagrams illustrating an example of a swirling flow deflected by a first rib and a second rib. [Diagram 5] 10A to 10C are diagrams illustrating an example of the flow of air taken in through a first suction hole and a second suction hole, the flow being changed by a deflected swirling flow. [Figure 6] FIG. 11 is a diagram showing an example of a verification result of cooling performance in a clutch housing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. EXAMPLES

[0010] Fig. 1 is a partial cross-sectional view showing an example of a clutch 12 and a release mechanism 14 accommodated in a clutch housing 10 to which the present invention is applied. In Fig. 1, a vehicle (not shown) includes the clutch housing 10, the clutch 12, the release mechanism 14, an engine 16, a transmission 18, and an end plate 20. The end plate 20 is interposed between an engine block 16a of the engine 16 and the clutch housing 10. The engine block 16a and the clutch housing 10 are connected via the end plate 20.

[0011] The clutch 12 is a friction clutch that switches between transmitting and interrupting power in a power transmission path between the crankshaft 16b and the input shaft 18a. The clutch 12 is, for example, a dry single-plate friction clutch. That is, the clutch 12 is provided between the crankshaft 16b and the input shaft 18a, and is a connecting / disconnecting mechanism that connects and disconnects the power transmission path between the engine 16 and the transmission 18. The clutch 12 is accommodated in the clutch housing 10 so as to be rotatable about a rotation axis CL. The rotation axis CL is the rotation axis of the clutch 12, and corresponds to the axial center (the same is also true for the axis) of the crankshaft 16b or the input shaft 18a. The crankshaft 16b is the output shaft of the engine 16, and is an output rotating member that outputs the power of the engine 16. The input shaft 18a is the input shaft of the transmission 18, and is an input rotating member to which the power of the engine 16 is input via the clutch 12.

[0012] The clutch 12 includes a flywheel 22, a clutch disc 24, a clutch cover 26, a pressure plate 28, and a diaphragm spring 30. The flywheel 22 is a disk-shaped rotating member connected to the crankshaft 16b by a bolt. The clutch disc 24 is formed in a disk shape, and an inner peripheral portion is spline-fitted to the input shaft 18a. A torsional damper 32 is interposed on the inner peripheral side of the clutch disc 24. The clutch cover 26 is formed in a disk shape, and an outer peripheral side is fastened to the flywheel 22 by a bolt. The pressure plate 28 is formed in an annular shape, is housed in the clutch cover 26, and is disposed on the opposite side of the flywheel 22 with respect to the clutch disc 24 in the direction of the rotation axis CL. The diaphragm spring 30 is formed in a disk shape, is attached to the clutch cover 26, and biases the pressure plate 28 toward the clutch disc 24 at its outer peripheral end.

[0013] The release mechanism 14 is disposed around the input shaft 18a and includes a release bearing 34, a release fork 36, a fork support 38, and a release cylinder 40. The release bearing 34 is formed in an annular shape and is attached to the input shaft 18a so as to be movable relative to the input shaft 18a in the axial direction. The end face of the release bearing 34 on the engine 16 side in the axial direction abuts against the inner peripheral end of the diaphragm spring 30. The release fork 36 is a longitudinal member and has a pressing portion 36a formed in the middle portion. The release bearing 34 on the transmission 18 side in the axial direction abuts against the pressing portion 36a. The release fork 36 is supported rotatably with the fork support 38, which is in contact with the release fork 36 near one end in the longitudinal direction, as a fulcrum, and the other end in the longitudinal direction abuts against the tip of the rod 40a of the release cylinder 40. The release cylinder 40 is attached to the clutch housing 10 by being inserted into a mounting hole 10a formed in the clutch housing 10 from the rod 40a side.

[0014] The release cylinder 40 is mechanically linked to a clutch pedal (not shown), and the rod 40a is moved in accordance with the amount of clutch pedal operation. When the clutch pedal is not depressed, the stroke amount of the release cylinder 40 is zero, and the rod 40a is in the state where it has moved to the furthest position axially toward the transmission 18. In this state, the biasing force of the diaphragm spring 30 moves the release bearing 34 and the release fork 36 to positions where the clutch 12 is in the engaged state.

[0015] On the other hand, when the clutch pedal is operated, the rod 40a is moved toward the engine 16 in accordance with the amount of clutch pedal operation. When the release fork 36 is rotated about the fork support 38 as a fulcrum in accordance with the amount of movement of the rod 40a, the pressing portion 36a presses the release bearing 34, causing the release bearing 34 to move toward the engine 16 in the direction of the rotation axis CL. At this time, the diaphragm spring 30 is deformed in proportion to the amount of axial movement of the release bearing 34, and the pressing force with which the diaphragm spring 30 presses the pressure plate 28 decreases, causing the clutch 12 to be switched to the disengaged side.

[0016] The clutch 12 transmits the power of the engine 16 to the transmission 18 by frictionally engaging the clutch disc 24 with the flywheel 22 and the pressure plate 28. This generates frictional heat between the clutch disc 24 and the flywheel 22 and the pressure plate 28, which may cause the clutch 12 to become hot. To counter this phenomenon, the clutch housing 10 has a function of facilitating the dissipation of frictional heat of the clutch 12 and improving cooling performance. The cooling function of the clutch housing 10 uses the atmosphere (the same applies to air) that is swirled around the clutch 12 as the clutch 12 rotates as a refrigerant.

[0017] Fig. 2 is an example of a front view of the clutch housing 10 as viewed from the engine 16 side in the direction of the rotation axis CL (see arrow A in Fig. 1). Fig. 3 is an example of an oblique side view of the clutch housing 10 as viewed from the mounting hole 10a side in a direction substantially perpendicular to the rotation axis CL (see arrow B in Fig. 2).

[0018] 1, 2 and 3, the clutch housing 10 has a cylindrical peripheral wall portion 50. The peripheral wall portion 50 has a fastening portion 52 for connecting to the engine 16 at an end portion on the engine 16 side, and a fastening portion 54 for connecting to the transmission 18 at an end portion on the transmission 18 side. The peripheral wall portion 50 has a clutch chamber 56 that rotatably houses the clutch 12. The inner diameter of the peripheral wall portion 50 is maximum at the fastening portion 52 on the engine 16 side, gradually decreases toward the transmission 18 side, and is minimum at the fastening portion 54 on the transmission 18 side.

[0019] The peripheral wall portion 50 is provided with a first suction hole 58 and a second suction hole 60 at a position adjacent to the fastening portion 54 on the transmission 18 side in the direction of the rotation axis CL. The first suction hole 58 and the second suction hole 60 are holes that communicate the outside of the peripheral wall portion 50 with the clutch chamber 56. The first suction hole 58 and the second suction hole 60 are suction holes that draw air outside the peripheral wall portion 50 into the clutch chamber 56 by a swirling flow FL (see solid arrow C), which is an air flow generated around the clutch 12 as the clutch 12 rotates. The first suction hole 58 and the second suction hole 60 each have a circumferential width longer than a radial width of the peripheral wall portion 50, and extend in the direction of the rotation axis CL or in a direction close to that direction. The first suction hole 58 and the second suction hole 60 are provided at positions spaced apart from each other in the direction of the swirling flow FL. The first suction hole 58 and the second suction hole 60 are each provided vertically above the rotation axis CL of the peripheral wall portion 50. For example, the first suction hole 58 is provided upstream of the swirling flow FL from a vertical upper portion of the rotation axis CL of the peripheral wall portion 50. The second suction hole 60 is provided downstream of the swirling flow FL from a vertical upper portion of the rotation axis CL of the peripheral wall portion 50. If the upper position in FIG. 2 is the 0 o'clock (12 o'clock) position clockwise and the lower position in FIG. 2 is the 6 o'clock position clockwise, the first suction hole 58 is provided at approximately 10 o'clock to 11 o'clock position, and the second suction hole 60 is provided at approximately 1 o'clock to 2 o'clock position.

[0020] The peripheral wall portion 50 is provided with a first exhaust hole 62 and a second exhaust hole 64 at a position adjacent to the fastening portion 52 on the engine 16 side in the direction of the rotation axis CL. The first exhaust hole 62 and the second exhaust hole 64 are holes that communicate the outside of the peripheral wall portion 50 with the clutch chamber 56. The first exhaust hole 62 and the second exhaust hole 64 are exhaust holes that exhaust the air in the clutch chamber 56 to the outside of the peripheral wall portion 50. The first exhaust hole 62 and the second exhaust hole 64 are each extended in a tangential direction of a circle centered on the rotation axis CL or in a direction close to that direction. The first exhaust hole 62 and the second exhaust hole 64 are each provided on a circle centered on the rotation axis CL and on a circle with a larger diameter than the circle on which the first suction hole 58 and the second suction hole 60 are located. The first exhaust hole 62 and the second exhaust hole 64 are provided at positions spaced apart from each other in the direction of the swirling flow FL. The first discharge hole 62 and the second discharge hole 64 are each provided vertically above the rotation axis CL in the peripheral wall portion 50. For example, the first discharge hole 62 is provided downstream of the swirling flow FL from the first suction hole 58 in the peripheral wall portion 50 and upstream of the swirling flow FL from the second suction hole 60. The second discharge hole 64 is provided downstream of the swirling flow FL from the second suction hole 60 in the peripheral wall portion 50.

[0021] A drain hole 66 is formed in a mating surface 52a when the engine block 16a and the clutch housing 10 are connected at the fastening portion 52, which is the end of the peripheral wall portion 50 on the engine 16 side. The drain hole 66 is a groove that communicates the outside of the peripheral wall portion 50 with the clutch chamber 56. The drain hole 66 is provided in a position of the mating surface 52a that is substantially below the rotation axis CL in the vertical direction. The drain hole 66 extends along a tangential direction of a circle centered on the rotation axis CL or a direction close to that direction. The drain hole 66 has a function of discharging water such as muddy water that has entered the clutch housing 10 to the outside. After the water in the clutch housing 10 is discharged, the drain hole 66 exerts a function of discharging air similar to the first discharge hole 62 and the second discharge hole 64.

[0022] In the clutch housing 10, the air swirling around the clutch 12 removes frictional heat from the clutch 12 and then is discharged to the outside through the first discharge hole 62, the second discharge hole 64, etc. (see Figure 2), thereby cooling the clutch 12.

[0023] The peripheral wall portion 50 has a plate-shaped first rib 68 formed adjacent to the first suction hole 58 on the upstream side of the swirling flow FL, and a plate-shaped first rib 70 formed adjacent to the second suction hole 60 on the upstream side of the swirling flow FL. The first ribs 68, 70 protrude from the inner wall surface of the peripheral wall portion 50 toward the rotation axis CL. That is, the first ribs 68, 70 protrude from the inner wall surface of the peripheral wall portion 50 in the radial direction of the peripheral wall portion 50 or in a direction close to that direction. In other words, the first ribs 68, 70 protrude from the inner wall surface of the peripheral wall portion 50 in the direction of the rotation axis CL or in a direction close to that direction. The first rib 68 is provided at approximately 10 o'clock in the clockwise direction, and the first rib 70 is provided at approximately 1 o'clock in the clockwise direction.

[0024] When the air sucked in through the first suction hole 58 and the second suction hole 60 flows through the clutch housing 10 in the rotational direction of the clutch 12, it hits the first rib 68 at approximately the 10 o'clock position in the clockwise direction and deflects the swirling flow FL, generating a negative pressure area and improving the intake performance and thus the cooling performance. The protruding length of the first ribs 68, 70 is determined in advance experimentally or by design, taking into consideration, for example, the intake performance.

[0025] A plate-shaped second rib 72 is formed on the peripheral wall portion 50 on the upstream side of the swirling flow FL with respect to the first rib 68 adjacent to the first suction hole 58, vertically above the rotation axis CL. The second rib 72 is formed on the upstream side of the swirling flow FL with respect to the first rib 68 adjacent to the first suction hole 58. The second rib 72 protrudes from the inner wall surface of the peripheral wall portion 50 toward the rotation axis CL. The second rib 72 has a predetermined length that is shorter than the first rib 68 in the radial direction of the peripheral wall portion 50. In other words, the second rib 72 has a predetermined length that is shorter than the first rib 68 in the direction of the rotation axis CL. The second rib 72 only needs to be formed on the first rib 68 adjacent to the first suction hole 58 provided upstream of the swirling flow FL with respect to the second suction hole 60, and does not need to be formed on the first rib 70 adjacent to the second suction hole 60. In this embodiment, two ribs of the same shape are provided side by side at a predetermined interval as the second rib 72. The second rib 72 is provided at approximately the 9 o'clock to 10 o'clock position in the clockwise direction.

[0026] FIG. 4 is a diagram for explaining an example of the swirling flow FL deflected by the first rib 68 and the second rib (the second rib 72, the comparative second rib Rc). FIG. 5 is a diagram for explaining an example of the flow of air taken in from the first suction hole 58 and the second suction hole 60, which is changed by the deflected swirling flow FL. In FIG. 4 and FIG. 5, (a) shows the present embodiment in which the second rib 72 having a predetermined protruding length in the direction of the rotation axis CL is used, and (b) shows a comparative example in which the comparative second rib Rc having a protruding length in the direction of the rotation axis CL equal to or longer than that of the first rib 68 is used. As shown in FIG. 4(b), the comparative second rib Rc has a relatively long protruding length, so that the flow path of the swirling flow FL is reduced, and the flow path is rapidly expanded downstream of the comparative second rib Rc, making it easier for the swirling flow FL to be deflected upstream of the first rib 68. Therefore, the first rib 68 does not deflect the swirling flow FL appropriately, and the swirling flow FL tends to disperse. Then, the air taken in through the first suction hole 58 and the second suction hole 60 is held down by the weakly deflected swirling flow FL (see β), and as shown in FIG. 5B, the flow of the taken in air (see arrow D) is diffused after hitting the clutch cover 26, and is less likely to move along the clutch cover 26. In contrast, as shown in FIG. 4A, the protruding length of the second rib 72 is relatively short, so that the swirling flow FL is less likely to be deflected upstream of the first rib 68. This makes it easier for the first rib 68 to deflect the swirling flow FL appropriately. Therefore, the air taken in through the first suction hole 58 and the second suction hole 60 is appropriately deflected and held down by the swirling flow FL (see α) that reaches a wide range, so that the flow of the taken in air (see arrow E) is directed toward the clutch cover 26, as shown in Fig. 5(a). This swirling flow FL makes it easier to cool the entire clutch cover 26.

[0027] By adding the second rib 72 at approximately the 9 o'clock to 10 o'clock position clockwise, optimizing the protruding length of the second rib 72 in the direction of the rotation axis CL, and using the first rib 68 at approximately the 10 o'clock position clockwise, the swirling flow FL in the clutch housing 10 can be efficiently directed to the entire clutch cover 26, and the heat resistance of the heat generating bodies such as the clutch cover 26, the clutch disc 24, and the flywheel 22 is improved. The predetermined length of the second rib 72 is determined in advance experimentally or by design, taking into consideration factors such as making it difficult for the swirling flow FL upstream of the first rib 68 to be deflected.

[0028] Returning to FIG. 2, the peripheral wall portion 50 is provided with a plate-shaped third rib 74 at a position adjacent to the first suction hole 58 on the downstream side of the swirling flow FL, and a plate-shaped third rib 76 at a position adjacent to the second suction hole 60 on the downstream side of the swirling flow FL. The third ribs 74, 76 protrude from the inner wall surface of the peripheral wall portion 50 toward the rotation axis CL. That is, the third ribs 74, 76 protrude from the inner wall surface of the peripheral wall portion 50 in the radial direction of the peripheral wall portion 50 or in a direction close to that direction. In other words, the third ribs 74, 76 protrude from the inner wall surface of the peripheral wall portion 50 in the direction of the rotation axis CL or in a direction close to that direction. The third rib 74 is provided at approximately 11 o'clock in the clockwise direction, and the third rib 76 is provided at approximately 2 o'clock in the clockwise direction.

[0029] By providing a first rib 68 and a third rib 74 for the first suction hole 58, and providing a first rib 70 and a third rib 76 for the second suction hole 60, air can be more efficiently sucked in through the first suction hole 58 and the second suction hole 60.

[0030] The peripheral wall portion 50 is provided with a plate-shaped guide rib 78 at a position adjacent to the first suction hole 58, the first rib 68, and the third rib 74 on the engine 16 side in the direction of the rotation axis CL, and a plate-shaped guide rib 80 at a position adjacent to the second suction hole 60, the first rib 70, and the third rib 76 on the engine 16 side in the direction of the rotation axis CL. The guide ribs 78, 80 are provided on a circle centered on the rotation axis CL, at a position on a circle with a larger diameter than the circle on which the first suction hole 58 and the second suction hole 60 are located, and at a position on a circle with a smaller diameter than the circle on which the first discharge hole 62 and the second discharge hole 64 are located. The guide ribs 78, 80 are provided in an arc shape extending in the circumferential direction, curved so as to bulge outward in the radial direction of the peripheral wall portion 50. The guide ribs 78, 80 protrude from the inner wall surface of the peripheral wall portion 50 toward the clutch chamber 56.

[0031] The guide ribs 78, 80 are ribs that facilitate guiding the swirling flow FL to the first discharge hole 62 and the second discharge hole 64. The guide ribs 78, 80 efficiently discharge a portion of the swirling flow FL in a tangent direction to a circle centered on the rotation axis CL or in a direction close to that direction.

[0032] When a vehicle travels on a flooded road, water may enter the clutch housing 10. For example, the water level WL shown by the dashed line in FIG. 2 indicates the water level when water accumulates at the bottom of the clutch housing 10 during flooding. The water that enters the clutch housing 10 is partially stirred up by the rotating clutch 12, and flows along the internal shape of the clutch housing 10 as the clutch 12 rotates, like the atmosphere. In other words, the water that enters the clutch housing 10 is carried away by the swirling flow FL (see the arrow F of the dashed double-dashed line in FIG. 2). A part of the water that enters the clutch housing 10 is efficiently discharged from the first discharge hole 62 and the second discharge hole 64 in the tangent direction of a circle centered on the rotation axis CL or in a direction close to that direction by the guide ribs 78 and 80. The first discharge hole 62 and the second discharge hole 64 function as drainage holes in addition to the function as exhaust holes.

[0033] In addition, the second rib 72 at approximately 9 o'clock to 10 o'clock position clockwise and the first rib 68 at approximately 10 o'clock position clockwise prevent the water that is stirred up from rising to the vertical upper portion of the rotation axis CL in the clutch housing 10 or its vicinity, and makes it easier for the water to fall upstream of the swirling flow FL from the vertical upper portion (see the two-dot chain arrow F in FIG. 2). This provides an effect of preventing or suppressing a deterioration in function caused by an excessive amount of water falling from the vertical upper portion of the rotation axis CL in the clutch housing 10 or its vicinity and splashing on the built-in components of the clutch 12. The built-in components of the clutch 12 are, for example, parts such as the release bearing 34 located at the center of the clutch housing 10. The deterioration in function of the clutch 12 is, for example, a malfunction caused by the inclusion of foreign matter or rust. The second rib 72 and the first rib 68 have a function of controlling the deflection of the swirling flow FL as well as a function of controlling water splashing.

[0034] In addition to the drainage holes 66, a first exhaust slit 82 and a second exhaust slit 84 are formed in the mating surface 52a of the peripheral wall portion 50 (see also Figs. 1 and 3). The first exhaust slit 82 and the second exhaust slit 84 are each a recess that communicates between the clutch chamber 56 and the outside of the peripheral wall portion 50. The first exhaust slit 82 and the second exhaust slit 84 are each formed in the mating surface 52a vertically above the rotation axis CL. The first exhaust slit 82 and the second exhaust slit 84 each extend along a tangent direction of a circle centered on the rotation axis CL or a direction close to that direction.

[0035] When the vehicle runs on a wet road, water may be splashed up to the upper vertical portion outside the clutch housing 10. Even if water drips from the upper vertical portion outside the clutch housing 10, it is preferable that the water does not enter the clutch housing 10 through the first exhaust slits 82 and the second exhaust slits 84. The first exhaust slits 82 and the second exhaust slits 84 are formed with an inclination so that dripping water does not enter. In other words, the direction in which the first exhaust slits 82 and the second exhaust slits 84 communicate between the clutch chamber 56 and the outside of the peripheral wall portion 50 is along the direction of the swirling flow FL and faces downward from the horizontal direction.

[0036] By adding the first exhaust slit 82 and the second exhaust slit 84 to the vicinity of the flywheel 22, an exhaust flow shown by the solid line G in Fig. 1 is generated, improving the heat dissipation effect from the flywheel 22, which is a part of the heat generating body. This has the effect of further improving the heat resistance of each part of the clutch 12, such as the flywheel 22.

[0037] FIG. 6 is a diagram showing an example of the verification result of the cooling performance of the clutch housing 10. FIG. 6 shows the result of measuring the temperature near the clutch cover 26 when the clutch 12 is operated. In FIG. 6, the comparative example shown by the dashed line is an example of the case where the comparative second rib Rc is used (see FIG. 4(b)), and the present embodiment shown by the solid line and the two-dot chain line is an example of the case where the second rib 72 is used (see FIG. 4(a)). Moreover, the present embodiment shown by the solid line is an example of the case where the first exhaust slit 82 and the second exhaust slit 84 are not provided, and the present embodiment shown by the two-dot chain line is an example of the case where the first exhaust slit 82 and the second exhaust slit 84 are provided. In the present embodiment shown by the solid line, the temperature rise near the clutch cover 26 is suppressed compared to the comparative example by optimizing the protruding length of the second rib 72 in the direction of the rotation axis CL. Furthermore, in this embodiment (exhaust slits added) shown by the dotted line, by providing the first exhaust slit 82 and the second exhaust slit 84, the temperature rise near the clutch cover 26 is further suppressed compared to the comparative example, as shown by the solid line.

[0038] As described above, according to this embodiment, the second rib 72 is formed on the peripheral wall portion 50 vertically above the rotation axis CL and on the upstream side of the swirling flow FL with respect to the first rib 68, so that the deflection of the swirling flow FL on the upstream side of the first rib 68 is suppressed, and the first rib 68 appropriately deflects the swirling flow FL, so that the swirling flow FL including the air newly drawn in from the first suction hole 58 and the second suction hole 60 can be efficiently applied to the entire clutch 12. This makes it easier for frictional heat of the clutch 12 to be dissipated. Therefore, the cooling performance of the clutch housing 10 can be further improved.

[0039] Furthermore, according to this embodiment, the mating surface 52a of the peripheral wall portion 50 is formed with the first exhaust slit 82 and the second exhaust slit 84, so that the frictional heat of the clutch 12 is further facilitated to dissipate, and the heat resistance of the clutch 12 is further improved.

[0040] Furthermore, according to this embodiment, the direction in which the first exhaust slits 82 and the second exhaust slits 84 connect the clutch chamber 56 to the outside of the peripheral wall portion 50 is along the direction of the swirling flow FL and faces downward rather than horizontally, so that water that has splashed onto the upper vertical surface outside the clutch housing 10 is less likely to enter the clutch housing 10 through the first exhaust slits 82 and the second exhaust slits 84.

[0041] Furthermore, according to this embodiment, the second rib 72 is formed upstream of the swirling flow FL relative to the first rib 68 adjacent to the first suction hole 58, so that the swirling flow FL can be efficiently directed against the entire clutch cover 26, improving the heat resistance of the clutch 12.

[0042] Furthermore, according to this embodiment, third ribs 74, 76 are formed in the peripheral wall portion 50 at positions adjacent to the downstream side of the swirling flow FL for each of the first suction hole 58 and the second suction hole 60, so that air is more efficiently sucked in through the first suction hole 58 and the second suction hole 60.

[0043] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0044] For example, in the above embodiment, the first suction hole 58 and the second suction hole 60 are exemplified as the suction holes, but the present invention is not limited to this. For example, the first suction hole 58 or the second suction hole 60 may be provided as the suction hole, or three or more suction holes may be provided. In short, it is sufficient that at least one suction hole is provided. In addition, when a plurality of suction holes are provided, the second rib 72 is provided on the upstream side of the swirling flow FL with respect to the first rib corresponding to the suction hole on the most upstream side of the swirling flow FL.

[0045] In addition, in the above-described embodiment, the first rib and the third rib are provided for one suction hole, but it is sufficient that at least the first rib is provided.

[0046] In the above embodiment, the first discharge hole 62 and the second discharge hole 64 are exemplified as the discharge holes, but this is not limited to the embodiment. For example, the first discharge hole 62 or the second discharge hole 64 may be provided as the discharge hole, or three or more discharge holes may be provided. In short, it is sufficient that at least one discharge hole is provided.

[0047] In the above-described embodiment, the guide ribs 78, 80 do not necessarily have to be provided. Similarly, the recesses (the first exhaust slit 82, the second exhaust slit 84) do not necessarily have to be provided.

[0048] In the above embodiment, two ribs of the same shape are provided side by side with a predetermined interval between them as the second rib 72, but it is sufficient that at least one second rib 72 is provided.

[0049] Furthermore, in the above-described embodiment, the end plate 20 is interposed between the engine block 16a and the clutch housing 10, but the end plate 20 does not necessarily have to be provided.

[0050] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0051] 10: Clutch housing 12: Clutch 16: Engine 16a: Engine block 16b: Crankshaft (output rotating member) 18a: Input shaft (input rotating member) 50: Peripheral wall part 52: Fastening part (end part on the engine side) 52a:Mating surface 56: Clutch room 58: 1st suction hole (suction hole) 60: 2nd suction hole (suction hole) 62: 1st discharge hole (discharge hole) 64:Second discharge hole (discharge hole) 68, 70: First rib 72: 2nd Rib 74, 76: 3rd rib 82: First exhaust slit (recess) 84: Second exhaust slit (recess) CL: Rotation axis FL: swirl flow

Claims

1. a clutch housing including a cylindrical peripheral wall portion having a clutch chamber that rotatably houses a friction clutch that switches between transmission and interruption of power in a power transmission path between an output rotating member that outputs engine power and an input rotating member to which the engine power is input, the peripheral wall portion being provided with an intake hole that draws air outside the peripheral wall portion into the clutch chamber by a swirling flow of air generated around the clutch as the clutch rotates, and a discharge hole that discharges air from the clutch chamber to the outside of the peripheral wall portion, the intake hole being provided in the peripheral wall portion vertically above a rotation axis of the clutch, A clutch housing characterized in that a first rib is formed on the peripheral wall portion at a position adjacent to the upstream side of the swirling flow relative to the suction hole, and a second rib is formed vertically above the rotation axis of the clutch and upstream of the swirling flow relative to the first rib, the second rib having a predetermined radial protruding length shorter than that of the first rib.

2. 2. The clutch housing according to claim 1, wherein a recess is formed in the mating surface at the engine side end of the peripheral wall portion when the engine block and the clutch housing are connected, the recess being vertically above the rotation axis of the clutch on the mating surface, the recess communicating the clutch chamber with the outside of the peripheral wall portion.

3. 3. The clutch housing according to claim 2, wherein the recessed portion has a direction communicating between the clutch chamber and the outside of the peripheral wall portion aligned with the direction of the swirling flow and directed downward relative to the horizontal direction.

4. the suction holes include a first suction hole provided in the peripheral wall portion upstream of the swirling flow from an upper portion in a vertical direction of the rotation axis, and a second suction hole provided in the peripheral wall portion downstream of the swirling flow from an upper portion in a vertical direction of the rotation axis, 4. The clutch housing according to claim 1, wherein the second rib is formed on an upstream side of the swirling flow with respect to the first rib adjacent to the first suction hole.

5. 5. The clutch housing according to claim 4, wherein a third rib is formed on the peripheral wall at a position adjacent to each of the first suction hole and the second suction hole on a downstream side of the swirling flow.

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