Sound insulation structure of vehicle transmission

Abstract

To provide a sound insulation structure of a vehicle transmission capable of performing oil change without removing a sound insulation cover, and capable of improving workability for oil change.SOLUTION: A sound insulation structure of a transmission 2 comprises: a transfer rear case 8; a rear sound insulation cover 14 attached to a rear wall 8C of the transfer rear case 8; and an oil supply boss part 8E that has an oil supply port 8b at its tip part, and protrudes rearward (outward) from the rear wall 8C of the transfer rear case 8. The oil supply boss part 8E penetrates the rear sound insulation cover 14, and a lower peripheral edge 8n of the oil supply port 8b protrudes outward from the rear sound insulation cover 14.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a sound insulation structure for a vehicle transmission.

Background Art

[0002] Conventionally, as a device for suppressing noise generated from a case of a vehicle drive device, a vehicle drive device described in Patent Document 1 is known.

[0003] This vehicle drive device covers a low-rigidity region, which is a region where the rigidity of the outer periphery of the rotating electric machine in the case is low, with a silencer (sound insulation cover) supported by a high-rigidity portion in the case that has higher rigidity than the low-rigidity region in the case, thereby effectively soundproofing the noise generated when the vibration of the gear mechanism is transmitted to the low-rigidity region.

[0004] By the way, a fuel supply port or an oil drain port for oil change is provided in the vehicle drive device, and oil is circulated inside and outside the case through the fuel supply port or the oil drain port during oil change or the like.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the vehicle drive device described in Patent Document 1, since the silencer is provided without considering the oil change work, there is a possibility that the oil dripping from the fuel supply port after oil supply may flow into the space between the silencer and the case.

[0007] In a conventional silencer, a sound-absorbing member having lower rigidity than the silencer body is provided. Therefore, if lubricating oil penetrates into the sound-absorbing member, the sound insulation performance may deteriorate, or dust or the like may adhere to the sound-absorbing member and contaminate it.

[0008] To solve such problems, it is necessary to perform an oil change operation after removing the silencer from the case, and there is a problem that the workability of the oil change operation deteriorates.

[0009] The present invention has been made paying attention to the above circumstances, and an object thereof is to provide a sound insulation structure for a vehicle transmission that can perform an oil change without removing a sound insulation cover and can improve the workability of the oil change operation.

Means for Solving the Problems

[0010] The present invention is a sound insulation structure for a vehicle transmission including a transmission case, a sound insulation cover attached to an outer peripheral surface of the transmission case, and a boss portion having an oil supply port or an oil drain port formed at a tip end and protruding outward from the outer peripheral surface of the transmission case, wherein the boss portion penetrates the sound insulation cover, and at least a part of the supply port or at least a part of the drain port protrudes outward from the sound insulation cover.

Effects of the Invention

[0011] Thus, according to the present invention as described above, it is possible to perform an oil change without removing the sound insulation cover, and the workability of the oil change operation can be improved.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

MODE FOR CARRYING OUT THE INVENTION

[0013] The sound insulation structure of a vehicle transmission according to an embodiment of the present invention includes a transmission case, a sound insulation cover attached to the outer peripheral surface of the transmission case, and a boss portion having an oil supply port or an oil drain port formed at the tip and protruding outward from the outer peripheral surface of the transmission case. The sound insulation structure of the vehicle transmission is such that the boss portion penetrates the sound insulation cover, and at least a part of the oil supply port or at least a part of the oil drain port protrudes outward from the sound insulation cover.

[0014] Thereby, the sound insulation structure of the vehicle transmission according to an embodiment of the present invention can perform oil change without removing the sound insulation cover, and can improve the workability of the oil change operation.

EXAMPLE

[0015] Hereinafter, the sound insulation structure of a vehicle transmission according to an embodiment of the present invention will be described with reference to the drawings. FIGS. 1 to 4 are views showing the sound insulation structure of a vehicle transmission according to an embodiment of the present invention.

[0016] In FIGS. 1 to 4, the up-down, front-back, and left-right directions are based on the vehicle transmission in the state of being arranged in the vehicle. The front-back direction of the vehicle is the front-back direction, the left-right direction (vehicle width direction) of the vehicle is the left-right direction, and the up-down direction (vehicle height direction) of the vehicle is the up-down direction.

[0017] First, the configuration will be described. In FIG. 1, a transmission 2 is mounted on a vehicle 1, and the transmission 2 is vertically installed below the floor panel 1A of the vehicle 1 in a state of being connected to an engine 3. The transmission 2 of the present embodiment constitutes a vehicle transmission.

[0018] The transmission 2 includes a transmission case 4, and the transmission case 4 is composed of a torque converter housing (hereinafter simply referred to as the "torque converter housing") 5, a front case 6, a transfer front case 7, and a transfer rear case 8.

[0019] The bottom wall of the transmission case 4 (the bottom wall of the front case 6, the bottom wall of the transfer front case 7, and the bottom wall of the transfer rear case 8) is inclined so that the rear side is positioned downward as it goes from the front case 6 to the transfer rear case 8.

[0020] Lubricating oil is stored in the transmission case 4 excluding the torque converter housing 5, and the transmission mechanism and transfer described later are lubricated by the oil.

[0021] A front flange portion 5A is formed along the circumferential direction of the torque converter housing 5 at the front end portion of the torque converter housing 5, and a flange portion of a cylinder block (not shown) of the engine is connected to the front flange portion 5A by bolts (not shown). Thereby, the engine is connected to the torque converter housing 5.

[0022] A rear flange portion 5B is formed along the circumferential direction of the torque converter housing 5 at the rear end portion of the torque converter housing 5. A front flange portion 6A is formed along the circumferential direction of the front case 6 at the front end portion of the front case 6, and the rear flange portion 5B is fastened to the front flange portion 6A by bolts (not shown). Thereby, the front case 6 is connected to the torque converter housing 5.

[0023] A rear flange portion 6B is formed along the circumferential direction of the front case 6 at the rear end portion of the front case 6.

[0024] At the front end of the transfer front case 7, a front flange portion 7A is formed along the circumferential direction of the transfer front case 7, and the front flange portion 7A is fastened to the rear flange portion 6B by bolts (not shown). Thereby, the front case 6 is connected to the transfer front case 7.

[0025] As shown in FIG. 2, an extension portion 7B is provided at the rear end portion of the transfer front case 7, and the extension portion 7B extends leftward from the rear end portion of the transfer front case 7. A rear flange portion 7C is formed on the outer peripheral edges of the rear end portion of the transfer front case 7 and the extension portion 7B.

[0026] The transfer rear case 8 extends in the left - right direction so as to face the transfer front case 7 in the front - rear direction.

[0027] A front flange portion 8A is formed in the circumferential direction at the front end portion of the transfer rear case 8, and the front flange portion 8A is fastened to the rear flange portion 7C by bolts (not shown).

[0028] That is, the front flange portion 8A of the transfer rear case 8 is fastened to the rear end portion and the extension portion 7B of the transfer front case 7 via the rear flange portion 7C.

[0029] The engine 3 burns fuel and converts thermal energy into mechanical energy. A torque converter (not shown) is housed in the torque converter housing 5. The torque converter amplifies and outputs the power of the engine 3.

[0030] Note that the transmission 2 of this embodiment is composed of an automatic transmission, but it may also be a manual transmission. In the case of a manual transmission, a clutch housing is provided instead of the torque converter housing 5, and a friction clutch is housed in the clutch housing.

[0031] A transmission mechanism (not shown) is housed inside the front case 6 and the transfer front case 7.

[0032] The transmission mechanism includes a plurality of axles arranged in parallel and a plurality of gears for shifting provided on the respective axles to connect the axles and transmit the power of the engine.

[0033] The transfer case 8 houses a transfer (not shown). As shown in FIGS. 1 and 2, a cylindrical portion 8B is formed at the rear end portion of the transfer case 8, and the tip end portion of a rear propeller shaft (not shown) is inserted into the cylindrical portion 8B.

[0034] A rear differential device (not shown), a rear drive shaft, and drive rear wheels are all connected to the rear propeller shaft.

[0035] A flange 9 is provided on the front surface on the right side of the extending portion 7B, and the rear end portion of a front propeller shaft (not shown) is connected to the flange 9. A front differential device (not shown), a front drive shaft, and drive front wheels are all connected to the front propeller shaft.

[0036] When an operation part (not shown) is operated by the driver, the transfer selects either two-wheel drive or four-wheel drive, and switches to a four-wheel drive state in which the driving force of the engine is transmitted to the front propeller shaft via the transmission mechanism, or a two-wheel drive state in which the driving force of the engine is not transmitted to the front propeller shaft via the transmission mechanism.

[0037] That is, the transfer performs two-wheel drive in which the driving force of the engine is always transmitted to the rear propeller shaft, and when in four-wheel drive, adds the driving force of the engine to the rear propeller shaft and transmits it to the front propeller shaft.

[0038] As shown in FIG. 2, a left sound insulation cover 11 and a right sound insulation cover 12 are attached to the torque converter housing 5.

[0039] The left sound insulation cover 11 includes a resin cover 11A and a sound absorption member 11B made of urethane rubber that is located between the resin cover 11A and the Torcon housing 5 and has a lower hardness than the resin cover 11A.

[0040] The resin cover 11A and the sound absorption member 11B are arranged at the lower part of the left side wall 5C of the Torcon housing 5 and extend in the front-rear direction along the Torcon housing 5 (see Fig. 1).

[0041] The front and rear ends of the resin cover 11A and the sound absorption member 11B are fixed to the left side wall 5C of the Torcon housing 5 by bolts 21A.

[0042] The lower part of the resin cover 11A covers the sound absorption member 11B from below. When foreign objects (such as small stones and snow) on the road surface are bounced up during the running of the vehicle 1, the foreign objects are made to collide with the resin cover 11A, thereby suppressing the contact of the foreign objects with the sound absorption member 11B and protecting the sound absorption member 11B.

[0043] The right sound insulation cover 12 includes a resin cover 12A and a sound absorption member 12B made of urethane rubber that is located between the resin cover 12A and the Torcon housing 5 and has a lower hardness than the resin cover 12A.

[0044] The resin cover 12A and the sound absorption member 12B are arranged at the lower part of the right side wall of the Torcon housing 5 and extend in the front-rear direction along the Torcon housing 5.

[0045] The front and rear ends of the resin cover 12A and the sound absorption member 12B are fixed to the right side wall of the Torcon housing 5 by bolts 21B (see Fig. 2).

[0046] The lower part of the resin cover 12A covers the sound absorption member 12B from below. When foreign objects on the road surface are bounced up during the running of the vehicle 1, the foreign objects are made to collide with the resin cover 12A, thereby suppressing the contact of the foreign objects with the sound absorption member 12B and protecting the sound absorption member 12B.

[0047] The sound radiated from the torque converter housing 5 that houses the torque converter is absorbed by the sound-absorbing member 11B of the left sound-insulating cover 11 and the sound-absorbing member 12B of the right sound-insulating cover 12. Thereby, the noise radiated from the transmission case 4 can be suppressed by the left sound-insulating cover 11 and the right sound-insulating cover 12.

[0048] As shown in FIG. 2, a front sound-insulating cover 13 is attached to the front surface of the extension portion 7B. The front sound-insulating cover 13 includes a resin cover 13A and a sound-absorbing member 13B made of urethane rubber that is located between the resin cover 13A and the extension portion 7B and has a lower hardness than the resin cover 13A.

[0049] The lower part of the resin cover 13A extends below the lower part of the sound-absorbing member and covers the lower part of the sound-absorbing member 13B from below.

[0050] The resin cover 13A and the sound-absorbing member 13B are fixed to the front surface of the extension portion 7B by bolts 21C.

[0051] As shown in FIGS. 3 and 4, a rear sound-insulating cover 14 is attached to the rear surface of the transfer case 8. The rear sound-insulating cover 14 includes a resin cover 14A and a sound-absorbing member 14B made of urethane rubber that is located between the resin cover 14A and the transfer case 8 and has a lower hardness than the resin cover 14A.

[0052] The lower part of the resin cover 14A extends below the lower part of the sound-absorbing member 14B and covers the lower part of the sound-absorbing member 14B from below.

[0053] The resin cover 14A and the sound-absorbing member 14B are fixed to the rear surface of the transfer case 8 by bolts 21D.

[0054] The lower part of the resin cover 13A covers the sound-absorbing member 13B from below, and the lower part of the resin cover 14A covers the sound-absorbing member 14B from below.

[0055] When a foreign object on the road surface is bounced up during the running of the vehicle 1, by causing the foreign object to collide with the resin covers 13A and 14A, it is possible to prevent the foreign object from coming into contact with the sound absorption member 13B on the resin cover 13A side and the sound absorption member 14B on the resin cover 14A side, and protect the sound absorption members 13B and 14B.

[0056] The sound radiated from the transfer case 8 that houses the transfer is absorbed by the sound absorption member 13B of the front sound insulation cover 13 and the sound absorption member 14B of the rear sound insulation cover 14. Thereby, the noise radiated from the transmission case 4 can be suppressed by the front sound insulation cover 13 and the rear sound insulation cover 14.

[0057] As shown in FIG. 2, a right sound insulation cover 15 is attached to the right side wall of the front case 6. The right sound insulation cover 15 has a resin cover 15A and a sound absorption member 15B (see FIG. 3) made of urethane rubber that is located between the resin cover 15A and the front case 6 and has a lower hardness than the resin cover 15A.

[0058] The resin cover 15A and the sound absorption member 15B extend in the front-rear direction of the front case 6 from the front flange portion 6A to the rear flange portion 6B of the front case 6.

[0059] The front and rear ends of the resin cover 15A and the sound absorption member 15B are fixed to the right side wall of the front case 6 by bolts 21E.

[0060] The lower part of the resin cover 15A covers the sound absorption member 15B from below. When a foreign object on the road surface is bounced up during the running of the vehicle 1, by causing the foreign object to collide with the resin cover 15A, it is possible to prevent the foreign object from coming into contact with the sound absorption member 15B and protect the sound absorption member 15B.

[0061] As shown in FIGS. 1 and 2, a left sound insulation cover 16 is attached to the left side wall 6D of the front case 6. The left sound insulation cover 16 has a resin cover 16A and a sound absorption member 16B made of urethane rubber that is located between the resin cover 16A and the front case 6 and has a lower hardness than the resin cover 16A.

[0062] The resin cover 16A and the sound absorption member 16B extend in the front-rear direction of the front case 6 from the front flange portion 6A to the rear flange portion 6B of the front case 6.

[0063] The front and rear ends of the resin cover 16A and the sound absorption member 16B are fixed to the left side wall 6D of the front case 6 by bolts 21F.

[0064] The lower part of the resin cover 16A covers the sound absorption member 16B from below. When foreign objects on the road surface are bounced up during the running of the vehicle 1, by causing the foreign objects to collide with the resin cover 16A, it is possible to prevent the foreign objects from contacting the sound absorption member 16B and protect the sound absorption member 16B.

[0065] The sound radiated from the front case 6 that houses the speed reduction mechanism is absorbed by the sound absorption member 15B of the right sound insulation cover 15 and the sound absorption member 16B of the left sound insulation cover 16. Thereby, the noise radiated from the transmission case 4 can be suppressed by the right sound insulation cover 15 and the left sound insulation cover 16.

[0066] As shown in FIG. 3, a hollow cylindrical oil drain boss portion 8D is provided at the lower part of the rear wall 8C of the transfer rear case 8 that faces the extending portion 7B of the transfer front case 7 in the front-rear direction.

[0067] The oil drain boss portion 8D projects rearward (outward) through a semi-circular notch 14a formed in the lower part of the rear sound insulation cover 14 from the rear wall 8C of the transfer rear case 8. That is, the oil drain boss portion 8D of the present embodiment is not covered by the rear sound insulation cover 14.

[0068] The rear sound insulation cover 14 is arranged so as to wrap around the upper side of the oil drain boss portion 8D, and houses the oil drain boss portion 8D inside the semi-circular notch 14a.

[0069] Since the lower part of the drain boss portion 8D is coupled to the front flange portion 8A of the transfer case 8, it has high rigidity and less sound radiation. Therefore, the rear sound insulation cover 14 is disposed on the side and upper side of the drain boss portion 8D.

[0070] Since the rear sound insulation cover 14 is disposed on the side and upper side of the drain boss portion 8D, it is possible to suppress the lubricating oil discharged from the drain boss portion 8D from adhering to or penetrating into the sound absorbing member, thereby preventing a decrease in sound insulation performance.

[0071] The transmission case 4 of the present embodiment is inclined so that the rear side is positioned downward as it goes from the front case 6 to the transfer case 8. Therefore, the drain boss portion 8D projects obliquely downward from the rear wall 8C of the transfer case 8.

[0072] An oil drain port 8a is formed at the tip of the drain boss portion 8D. The oil drain port 8a communicates the inside and outside of the transmission case 4. The oil drain port 8a is closed by a drain plug (not shown), and when the drain plug is removed from the oil drain port 8a, the oil stored in the transmission case 4 is discharged from the oil drain port 8a to the outside of the transmission case 4.

[0073] As shown in FIGS. 3 and 4, a hollow cylindrical oil supply boss portion 8E is provided on the rear wall 8C of the transfer case 8 facing the extending portion 7B of the transfer front case 7 in the front-rear direction. The oil supply boss portion 8E is located above the drain boss portion 8D.

[0074] The oil supply boss portion 8E projects rearward (outward) from the rear wall 8C of the transfer case 8 and projects obliquely downward from the rear wall 8C of the transfer case 8 in the same manner as the drain boss portion 8D.

[0075] A fuel filling port 8b is formed at the tip of the boss portion 8E for fuel filling. As shown in FIG. 4, a through hole 8c is formed in the rear wall 8C of the transfer case 8, and the fuel filling port 8b communicates with the inside of the transmission case 4 through the oil passage 8d inside the boss portion 8E for fuel filling and the through hole 8c.

[0076] The fuel filling port 8b is closed by a filler plug (not shown). When the filler plug is removed from the fuel filling port 8b, oil can be filled into the transmission case 4 through the oil passage 8d and the through hole 8c from the fuel filling port 8b.

[0077] The rear wall 8C of this embodiment constitutes the outer peripheral surface of the transmission case, and the boss portion 8E for fuel filling constitutes the boss portion.

[0078] As shown in FIG. 4, circular through holes 14b and 14c are formed in the resin cover 14A and the sound-absorbing member 14B, respectively. The boss portion 8E for fuel filling protrudes outward (rearward) from the rear sound insulation cover 14 through the through holes 14b and 14c.

[0079] Specifically, the lower peripheral edge 8n of the fuel filling port 8b extends rearward from the upper peripheral edge 8m, and the lower peripheral edge 8n of the fuel filling port 8b protrudes rearward from the through hole 14b of the resin cover 14A. Here, the lower peripheral edge 8n of the fuel filling port 8b corresponds to the lower semi-circular portion of the fuel filling port 8b, and the upper peripheral edge 8m corresponds to the upper semi-circular portion of the fuel filling port 8b.

[0080] That is, the boss portion 8E for fuel filling penetrates the rear sound insulation cover 14, and the lower peripheral edge 8n, which is a part of the fuel filling port 8b, protrudes rearward from the rear sound insulation cover 14.

[0081] Note that the upper peripheral edge 8m of the fuel filling port 8b may protrude rearward from the resin cover 14A, but it may be located closer to the rear wall 8C of the transfer case 8 than the lower peripheral edge 8n and closer to the rear wall 8C of the transfer case 8 than the resin cover 14A.

[0082] When it is positioned on the rear wall 8C side of the transfer case 8 rather than the resin cover 14A, the protruding amount from the transfer case 8 can be reduced.

[0083] Further, a recess 14e is formed in the outer peripheral side surface 14d of the rear sound insulation cover 14, that is, the outer peripheral side surface 14d of the resin cover 14A.

[0084] The recess 14e is formed below the through holes 14b and 14c. The upper edge of the recess 14e is the through hole 14c, and the upper edge of the recess 14e is recessed toward the rear wall 8C side of the transfer case 8 from the lower peripheral edge 8n of the oil supply port 8b of the oil supply boss portion 8E. The rear wall 8C of the present embodiment constitutes the outer peripheral side surface of the transmission case, and the outer peripheral side surface 14d of the resin cover 14A constitutes the outer peripheral side surface of the sound insulation cover.

[0085] Next, the operation and effect of the sound insulation structure of the transmission 2 of the present embodiment will be described. In FIG. 4, the oil O flowing through the oil supply boss portion 8E is shown by a thick line with hatching.

[0086] When performing an oil change, the drain plug is removed from the oil drain port 8a, and the oil stored in the transmission case 4 is discharged to the outside from the oil drain port 8a.

[0087] Since the transmission case 4 is arranged to be inclined so that the rear side is positioned downward as it goes from the front case 6 to the transfer case 8, the oil stored in the transmission case 4 can be easily discharged from the transfer case 8 located at the rear.

[0088] When the oil discharge is completed, after inserting the drain plug into the oil drain port 8a to close the oil drain port 8a, the filler plug is removed from the oil supply port 8b, and a nozzle is inserted into the oil supply port 8b to inject new oil into the transmission case 4 from the oil supply port 8b.

[0089] The sound insulation structure of the transmission 2 in this embodiment includes a transfer case 8, a rear sound insulation cover 14 attached to the rear wall 8C of the transfer case 8, and a fuel supply boss portion 8E that has an oil supply port 8b formed at its tip and protrudes rearward (outward) from the rear wall 8C of the transfer case 8.

[0090] The fuel supply boss portion 8E penetrates the rear sound insulation cover 14, and the lower peripheral edge 8n of the fuel supply port 8b protrudes outward from the rear sound insulation cover 14.

[0091] Thereby, oil change can be easily performed with the rear sound insulation cover 14 attached to the transfer case 8, and the workability of the oil change operation can be improved.

[0092] Also, when pulling out the nozzle from the fuel supply port 8b, oil may leak to the outside from the fuel supply port 8b. However, since the fuel supply port 8b protrudes rearward from the rear wall 8C of the transfer case 8, the oil O can be discharged from the fuel supply port 8b to the outside of the rear sound insulation cover 14.

[0093] Therefore, it is possible to suppress the oil O from flowing to the back side of the rear sound insulation cover 14 and prevent the oil from adhering to the sound absorption member 14B.

[0094] As a result, it is possible to prevent the oil from soaking into the sound absorption member 14B and suppress the deterioration of the sound insulation performance, and it is also possible to suppress the sound absorption member 14B from being contaminated by the oil.

[0095] Note that the fuel supply boss portion 8E in this embodiment penetrates the rear sound insulation cover 14, and the lower peripheral edge 8n of the fuel supply port 8b protrudes outward from the rear sound insulation cover 14. However, all of the fuel supply port 8b may protrude outward from the rear sound insulation cover 14.

[0096] Also, according to the sound insulation structure of the transmission 2 in this embodiment, the lower peripheral edge 8n of the fuel supply port 8b extends outward from the upper peripheral edge 8m of the fuel supply port 8b.

[0097] As a result, the oil O can be discharged from the oil filling port 8b to the outside of the rear sound insulation cover 14, and the flow of the oil O to the back side of the rear sound insulation cover 14 can be more effectively suppressed.

[0098] Therefore, it is possible to more effectively prevent the oil from soaking into the sound absorption member 14B and suppress the reduction of the sound insulation performance, and it is also possible to more effectively suppress the contamination of the sound absorption member 14B by the oil.

[0099] Further, according to the sound insulation structure of the transmission 2 of the present embodiment, the resin cover 14A and the sound absorption member 14B of the rear sound insulation cover 14 have through holes 14b and 14c through which the oil supply boss portion 8E penetrates, and the outer peripheral side surface 14d of the resin cover 14A located below the through holes 14b and 14c is recessed from the lower peripheral edge 8n of the oil filling port 8b to the rear wall 8C of the transfer case 8.

[0100] As a result, the lower peripheral edge 8n of the oil filling port 8b can be reliably protruded behind the through hole 14c.

[0101] That is, the oil O can flow from the lower peripheral edge 8n of the oil supply boss portion 8E along the outer peripheral side surface 14d of the resin cover 14A to the lower side of the resin cover 14A.

[0102] Therefore, the oil can be discharged from the oil filling port 8b to the outside of the rear sound insulation cover 14, and the flow of the oil to the back side of the rear sound insulation cover 14 can be more effectively suppressed.

[0103] As a result, it is possible to more effectively prevent the oil from soaking into the sound absorption member 14B and suppress the reduction of the sound insulation performance, and it is also possible to more effectively suppress the contamination of the sound absorption member 14B by the oil.

[0104] Note that the sound absorption members 11B, 12B, 13B, 14B, 15B, and 16B of the sound insulation covers 11, 12, 13, 14, 15, and 16 may be selected from urethane materials according to the frequency band of the radiated sound generated from the mounting portion to the transmission case 4.

[0105] Also, even for the sound-absorbing members of the same sound-insulating cover, a urethane material corresponding to the frequency band of the radiated sound generated from the attachment site to the transmission case 4 may be selected. For example, the upper part and the lower part of the sound-absorbing member of the left sound-insulating cover 16 may be divided into urethane materials corresponding to the frequency band of the radiated sound.

[0106] Also, when the oil drain boss portion 8D is covered by the rear sound-insulating cover 14, the oil drain boss portion 8D may be configured to penetrate the rear sound-insulating cover 14, and at least a part of the oil drain port 8a may protrude rearward (outside) from the rear sound-insulating cover 14.

[0107] Also, when both the oil drain boss portion 8D and the oil supply boss portion 8E are covered by the rear sound-insulating cover 14, the oil drain boss portion 8D and the oil supply boss portion 8E may be configured to penetrate the rear sound-insulating cover 14, and at least a part of the oil drain port 8a and at least a part of the oil supply port 8b may protrude rearward (outside) from the rear sound-insulating cover 14.

[0108] Although embodiments of the present invention have been disclosed, it is obvious that those skilled in the art can make changes without departing from the scope of the present invention. It is intended that all such modifications and equivalents be included in the following claims.

Explanation of Reference Numerals

[0109] 2 Transmission (vehicle transmission) 8 Transfer case (transmission case) 8b Oil supply port 8C Rear wall (outer peripheral surface of the transmission case) 8E Oil supply boss portion (boss portion) 8m Upper peripheral edge 8n Lower peripheral edge 14 Rear sound-insulating cover (sound-insulating cover) 14b, 14c Through hole 14d Outer peripheral side surface (outer peripheral side surface of the sound-insulating cover)

Claims

1. A sound insulation structure for a vehicle transmission, comprising a transmission case, a sound insulation cover attached to an outer peripheral surface of the transmission case, and a boss portion having an oil supply port or an oil drain port formed at a tip portion and protruding outward from the outer peripheral surface of the transmission case, wherein the boss portion penetrates the sound insulation cover, and at least a part of the oil supply port or at least a part of the oil drain port protrudes outward from the sound insulation cover. A sound insulation structure for a vehicle transmission characterized by this.

2. The sound insulation structure for a vehicle transmission according to claim 1, wherein a lower peripheral edge of the oil supply port or the oil drain port extends outward from an upper peripheral edge of the oil supply port or the oil drain port.

3. The sound insulation cover has a through hole through which the boss portion penetrates, and an outer peripheral side surface of the sound insulation cover located below the through hole is recessed toward an outer peripheral side surface of the transmission case from a lower peripheral edge of the oil supply port or the oil drain port. A sound insulation structure for a vehicle transmission according to claim 1 or claim 2, characterized by this.

Images