Sound insulation structure for transmission for vehicle

Abstract

To provide a sound insulation structure for a vehicular transmission that can suppress a transmission case from vibrating by the use of a sound insulation cover in a shape corresponding to a lateral rib reinforcing a side wall of the transmission case, and also can suppress sound radiation of the transmission case.SOLUTION: A sound insulation structure of a transmission 2 has a left sound insulation cover 16 fitted to a left side wall 6D of a front case 6, wherein the left sound insulation cover 16 is constituted including a resin cover 16A and a sound insulation member 16B which is provided integrally with the resin cover 16A between the left side wall 6D of the front case 6 and the resin cover 16A, and has lower rigidity than the resin cover 16A. The sound absorption member 16B has: an upper swollen part 16a arranged above a lateral rib 6E and abuts on a top surface of the lateral rib 6E to vertically overlap the lateral rib 6E; and a lower swollen part 16b arranged below a lateral rib 6F, and abuts on a reverse surface of the lateral rib 6F to vertically overlap the lateral rib 6F.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 part having higher rigidity than the low-rigidity region in the case, thereby effectively soundproofing the noise generated by the vibration of the gear mechanism being transmitted to the low-rigidity region.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the vehicle drive device described in Patent Document 1, the main focus is on covering the low-rigidity region of the case with a silencer to absorb the sound emitted from the low-rigidity region, and no consideration is given to effectively suppressing the vibration of the low-rigidity region.

[0006] 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 suppress the vibration of the transmission case by using a sound insulation cover having a shape corresponding to horizontal ribs for reinforcing the side wall of the transmission case, and can suppress the radiated sound of the transmission case.

Means for Solving the Problems

[0007] The present invention has a transmission case and a sound insulation cover attached to a side wall of the transmission case. The transmission case extends in the front-rear direction of the side wall and protrudes in the left-right direction from the side wall, and has a pair of horizontal ribs for reinforcing the transmission case. The pair of horizontal ribs includes an upper horizontal rib and a lower horizontal rib disposed below the upper horizontal rib. The sound insulation cover is a sound insulation structure of a vehicle transmission, and includes a resin cover and a sound absorption member provided integrally with the resin cover between the side wall and the resin cover, and having a lower rigidity than the resin cover. The sound absorption member is disposed above the upper horizontal rib and has an upper bulging portion that abuts against the upper surface of the upper horizontal rib in the vertical direction, and is disposed below the lower horizontal rib and has a lower bulging portion that abuts against the lower surface of the lower horizontal rib in the vertical direction.

Effects of the Invention

[0008] According to the present invention as described above, it is possible to suppress the vibration of the transmission case by using a sound insulation cover having a shape corresponding to the horizontal ribs for reinforcing the side wall of the transmission case, and to suppress the radiated sound of the transmission case.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0010] The sound insulation structure of a vehicle transmission according to an embodiment of the present invention includes a transmission case and a sound insulation cover attached to a side wall. The transmission case extends in the front-rear direction of the side wall and protrudes in the left-right direction from the side wall, and has a pair of horizontal ribs for reinforcing the transmission case. The pair of horizontal ribs includes an upper horizontal rib and a lower horizontal rib disposed below the upper horizontal rib. The sound insulation cover is configured to include a resin cover and a sound absorption member provided integrally with the resin cover between the side wall and the resin cover and having a lower rigidity than the resin cover. The sound absorption member is disposed above the upper horizontal rib and has an upper bulging portion that abuts against the upper surface of the upper horizontal rib so as to overlap in the vertical direction, and is disposed below the lower horizontal rib and has a lower bulging portion that abuts against the lower surface of the lower horizontal rib so as to overlap in the vertical direction.

[0011] Accordingly, the sound insulation structure of a vehicle transmission according to an embodiment of the present invention can suppress the vibration of the transmission case by using a sound insulation cover having a shape corresponding to the horizontal ribs that reinforce the side wall of the transmission case, and can suppress the radiated sound of the transmission case.

Example

[0012] 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 6 are views showing the sound insulation structure of a vehicle transmission according to an embodiment of the present invention.

[0013] In FIGS. 1 to 6, the vertical, front-rear, and left-right directions are based on the vehicle transmission in a state where it is disposed in the vehicle. The front-rear direction of the vehicle is the front-rear direction, the left-right direction (vehicle width direction) of the vehicle is the left-right direction, and the vertical direction (vehicle height direction) of the vehicle is the vertical direction.

[0014] First, the configuration will be described. In FIG. 1, a transmission 2 is mounted on a vehicle 1. The transmission 2 is vertically installed below the floor panel 1A of the vehicle 1 while being connected to an engine 3. The transmission 2 of the present embodiment constitutes a vehicle transmission.

[0015] The transmission 2 includes a transmission case 4. The transmission case 4 is composed of a torque converter housing (hereinafter simply referred to as the "TC housing") 5, a front case 6, a transfer front case 7, and a transfer rear case 8.

[0016] The TC housing 5 of the present embodiment constitutes the front case, the front case 6 constitutes the intermediate case, and the transfer front case 7 constitutes the rear case.

[0017] A front flange portion 5A is formed along the circumferential direction of the TC housing 5 at the front end portion of the TC housing 5. The flange portion of an engine's cylinder block (not shown) is connected to the front flange portion 5A by bolts (not shown). Thereby, the engine is connected to the TC housing 5.

[0018] A rear flange portion 5B is formed along the circumferential direction of the TC housing 5 at the rear end portion of the TC 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. 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 TC housing 5.

[0019] 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.

[0020] 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.

[0021] As shown in FIG. 2, an extension portion 7B is provided at the rear end of the transfer front case 7, and the extension portion 7B extends leftward from the rear end of the transfer front case 7. A rear flange portion 7C is formed on the outer peripheral edges of the rear end of the transfer front case 7 and the extension portion 7B.

[0022] 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.

[0023] A front flange portion 8A is formed in the circumferential direction at the front end of the transfer rear case 8, and the front flange portion 8A is fastened to the rear flange portion 7C by bolts (not shown).

[0024] That is, the front flange portion 8A of the transfer rear case 8 is fastened to the rear end and the extension portion 7B of the transfer front case 7 via the rear flange portion 7C.

[0025] 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.

[0026] Note that the transmission 2 in 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.

[0027] A transmission mechanism (not shown) is housed inside the front case 6 and the transfer front case 7.

[0028] 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.

[0029] 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 of the transfer case 8, and the tip of a rear propeller shaft (not shown) is inserted into the cylindrical portion 8B.

[0030] A rear differential device (not shown), a rear drive shaft, and drive rear wheels are all connected to the rear propeller shaft.

[0031] A flange 9 is provided on the front surface on the right side of the extension portion 7B, and the rear end 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.

[0032] 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.

[0033] 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.

[0034] As shown in FIGS. 2 and 3, a left sound insulation cover 11 and a right sound insulation cover 12 are attached to the torque converter housing 5.

[0035] The left sound insulation cover 11 has 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The right sound insulation cover 12 has 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.

[0040] The resin cover 12A and the sound absorption member 12B are arranged at the lower part of the right side wall 5D (see Fig. 5) of the Torcon housing 5 and extend in the front-rear direction along the Torcon housing 5.

[0041] The front and rear ends of the resin cover 12A and the sound absorption member 12B are fixed to the right side wall 5D of the Torcon housing 5 by bolts 21B (see Fig. 2).

[0042] 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.

[0043] 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 insulation cover 11 and the sound-absorbing member 12B of the right sound insulation cover 12. Thereby, the noise radiated from the transmission case 4 can be suppressed by the left sound insulation cover 11 and the right sound insulation cover 12.

[0044] As shown in FIG. 2, a front sound insulation cover 13 is attached to the front surface of the extension portion 7B. The front sound insulation cover 13 includes a resin cover 13A and a sound-absorbing member 13B (see FIG. 5) 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.

[0045] The lower part of the resin cover 13A extends below the lower part of the sound-absorbing member 13B and covers the lower part of the sound-absorbing member 13B from below.

[0046] The resin cover 13A and the sound-absorbing member 13B are fixed to the front surface of the extension portion 7B by bolts 21C.

[0047] A rear sound insulation cover 14 is attached to the rear surface of the transfer case 8. The rear sound insulation 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.

[0048] 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.

[0049] The resin cover 14A and the sound-absorbing member 14B are fixed to the rear surface of the transfer case 8 by bolts 21D.

[0050] 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 covers 13A and 14A, it is possible to prevent the foreign objects from contacting the sound-absorbing members 13B and 14B and protect the sound-absorbing members 13B and 14B.

[0051] The sound radiated from the transfer case 8 in which the transfer is housed is absorbed by the sound-absorbing member 13B of the front sound insulation cover 13 and the sound-absorbing 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.

[0052] As shown in FIG. 4, a right sound insulation cover 15 is attached to the right side wall 6C of the front case 6 (see FIG. 2). The right sound insulation cover 15 has a resin cover 15A and a sound-absorbing member 15B 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.

[0053] The resin cover 15A and the sound-absorbing 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.

[0054] The front and rear ends of the resin cover 15A and the sound-absorbing member 15B are fixed to the right side wall 6C of the front case 6 by bolts 21E.

[0055] The lower part of the resin cover 15A covers the sound-absorbing member 15B from below. When a foreign object on the road surface is bounced up during the running of the vehicle 1, the foreign object collides with the resin cover 15A, thereby suppressing the foreign object from coming into contact with the sound-absorbing member 15B and protecting the sound-absorbing member 15B.

[0056] The sound radiated from the front case 6 that houses the reduction mechanism is absorbed by the right sound insulation cover 15. Thereby, the noise radiated from the transmission case 4 can be suppressed by the right sound insulation cover 15.

[0057] As shown in FIG. 3, horizontal ribs 6E, 6F, and 6G are provided on the left side wall 6D of the front case 6, and the horizontal ribs 6E, 6F, and 6G project from the left side wall 6D in the left-right direction (leftward in this embodiment).

[0058] The rear end of the horizontal rib 6E is connected to the rear flange portion 6B, and the horizontal rib 6E extends from the rear flange portion 6B to near the front flange portion 6A.

[0059] The horizontal rib 6F is provided below the horizontal rib 6E. The front end of the horizontal rib 6F is connected to the front flange portion 6A, and the rear end of the horizontal rib 6F is connected to the rear flange portion 6B. That is, the horizontal rib 6F is erected so as to protrude leftward from the left side wall 6D of the front case 6 from the front flange portion 6A to the rear flange portion 6B and extends in the front-rear direction.

[0060] The horizontal rib 6G is provided below the horizontal rib 6F. The front end of the horizontal rib 6G is connected to the front flange portion 6A, and the rear end of the horizontal rib 6G is connected to the rear flange portion 6B. That is, the horizontal rib 6G is erected so as to protrude leftward from the left side wall 6D of the front case 6 from the front flange portion 6A to the rear flange portion 6B and extends in the front-rear direction.

[0061] The horizontal ribs 6E, 6F, and 6G of this embodiment extend parallel to each other in the front-rear direction and reinforce the left side wall 6D of the front case 6.

[0062] Vertical ribs 6H, 6I, and 6J are provided on the left side wall 6D of the front case 6, and the vertical ribs 6H, 6I, and 6J protrude from the left side wall 6D in the left-right direction (leftward in this embodiment).

[0063] The vertical ribs 6H, 6I, and 6J extend in the vertical direction from the upper end to the lower end of the left side wall 6D of the front case 6, connect the horizontal rib 6E and the horizontal rib 6F, and connect the horizontal rib 6F and the horizontal rib 6G.

[0064] The left side wall 6D of the front case 6 of this embodiment constitutes the side wall of the transmission case. The horizontal rib 6F constitutes the upper horizontal rib, and the horizontal rib 6G constitutes the lower horizontal rib.

[0065] 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 includes a resin cover 16A and a sound absorption member 16B made of urethane rubber that is positioned between the resin cover 16A and the left side wall 6D of the front case 6 and has a lower hardness than the resin cover 16A.

[0066] The resin cover 16A is fixed to the sound absorption member 16B by adhesion or the like and is provided integrally with the sound absorption member 16B. The left sound insulation cover 16 of the present embodiment constitutes a sound insulation cover.

[0067] As shown in FIG. 4, an upper bulging portion 16a and a lower bulging portion 16b are provided on the sound absorption member 16B (see FIG. 6). The upper bulging portion 16a bulges from the upper part of the flat portion 16e of the sound absorption member 16B toward the left side wall 6D of the front case 6 and extends in the front-rear direction from the front flange portion 6A to the rear flange portion 6B along the horizontal rib 6F.

[0068] The lower bulging portion 16b is located below the upper bulging portion 16a, bulges from the lower part of the flat portion 16e of the sound absorption member 16B toward the left side wall 6D of the front case 6, and extends in the front-rear direction from the front flange portion 6A to the rear flange portion 6B along the horizontal rib 6G.

[0069] As shown in FIG. 4, the upper bulging portion 16a abuts on the upper surface of the horizontal rib 6F so as to overlap the horizontal rib 6F in the vertical direction, and the lower bulging portion 16b abuts on the lower surface of the horizontal rib 6G so as to overlap the horizontal rib 6G in the vertical direction.

[0070] That is, the upper bulging portion 16a and the lower bulging portion 16b are in close contact with the horizontal rib 6F and the horizontal rib 6G by elastic force and sandwich the horizontal rib 6F and the horizontal rib 6G from the vertical direction.

[0071] As shown in FIG. 3, bosses 6a, 6b into which bolts 21F (see FIG. 6) are screwed and a boss 6c into which a pin 21G (see FIG. 6) is fitted are formed on the left side wall 6D of the front case 6. The bosses 6a and 6c are provided side by side in the front-rear direction on the horizontal rib 6F, and the boss 6b is provided on the horizontal rib 6G.

[0072] The resin cover 16A and the sound-absorbing member 16B are integrally fixed to the left side wall 6D of the front case 6 by inserting a pin 21G attached to the resin cover 16A into a hole formed in a boss 6c and positioning it, and then screwing a bolt 21F into bosses 6a and 6b.

[0073] As shown in FIG. 4, when the left sound insulation cover 16 is attached to the left side wall 6D of the front case 6, the upper bulging portion 16a abuts on the upper surface of the horizontal rib 6F so as to overlap the horizontal rib 6F in the vertical direction, and the lower bulging portion 16b abuts on the lower surface of the horizontal rib 6G so as to overlap the horizontal rib 6G in the vertical direction.

[0074] In addition, the sound-absorbing member 16B abuts on the tips of the vertical ribs 6H, 6I, and 6J in the protruding directions (see FIG. 5). In addition to this, as shown in FIG. 1, the front end portion 16c of the sound-absorbing member 16B abuts on the front flange portion 6A between the horizontal ribs 6F and 6G, and the rear end portion 16d of the sound-absorbing member 16B abuts on the rear flange portion 6B between the horizontal ribs 6F and 6G.

[0075] The front end portion 16c of the sound-absorbing member 16B of the present embodiment constitutes a front contact portion, and the rear end portion 16d of the sound-absorbing member 16B constitutes a rear contact portion.

[0076] As shown in FIG. 4, since the upper bulging portion 16a of the left sound insulation cover 16 abuts on the upper surface of the horizontal rib 6F so as to overlap the horizontal rib 6F in the vertical direction, and the lower bulging portion 16b abuts on the lower surface of the horizontal rib 6G so as to overlap the horizontal rib 6G in the vertical direction, a space 17 corresponding to the protruding lengths of the horizontal ribs 6F and 6G is formed between the left side wall 6D of the front case 6 and the left sound insulation cover 16.

[0077] That is, a space 17 surrounded by the upper bulging portion 16a, the lower bulging portion 16b, the front case 6, and the sound-absorbing member 16B is formed between the front case 6 and the left sound insulation cover 16.

[0078] A protruding portion 16C is provided at the lower part of the resin cover 16A. The protruding portion 16C extends downward from the lower end portion 16f of the sound-absorbing member 16B and covers the sound-absorbing member 16B from below.

[0079] Next, the effect of the sound insulation structure of the transmission 2 of this embodiment will be described. The sound insulation structure of the transmission 2 of this embodiment has a front case 6. The front case 6 has a horizontal rib 6E that extends in the front-rear direction of the left side wall 6D and protrudes in the left-right direction from the left side wall 6D to reinforce the front case 6, and a horizontal rib 6F disposed below the horizontal rib 6E.

[0080] 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 is integrally provided with the resin cover 16A between the resin cover 16A and the left side wall 6D of the front case 6 and includes a sound-absorbing member 16B having a lower rigidity than the resin cover 16A.

[0081] The sound-absorbing member 16B is disposed above the horizontal rib 6E and has an upper bulging portion 16a that overlaps and abuts on the upper surface of the horizontal rib 6E in the vertical direction, and is disposed below the horizontal rib 6F and has a lower bulging portion 16b that overlaps and abuts on the lower surface of the horizontal rib 6F in the vertical direction.

[0082] Thereby, a space 17 surrounded by the upper bulging portion 16a, the lower bulging portion 16b, the front case 6, and the sound-absorbing member 16B can be formed, and the noise radiated from the transmission case 4 can be suppressed using this space as an air layer.

[0083] Furthermore, in addition to providing the horizontal ribs 6F and 6G on the left side wall 6D of the front case 6, by bringing the upper bulging portion 16a and the lower bulging portion 16b made of urethane rubber into contact with the horizontal ribs 6F and 6G respectively, the gaps between the upper bulging portion 16a and the horizontal rib 6F and between the lower bulging portion 16b and the horizontal rib 6G can be reduced, the airtightness of the space 17 can be enhanced, and the noise radiated from the transmission case 4 can be suppressed.

[0084] In addition, the upper bulging portion 16a and the lower bulging portion 16b can reinforce the horizontal ribs 6F and 6G, suppress the vibration of the left side wall 6D of the front case 6, and suppress the noise radiated from the transmission case 4.

[0085] That is, the sound insulation structure of the transmission 2 of the present embodiment uses the left sound insulation cover 16 having a shape corresponding to the horizontal ribs 6F and 6G that reinforce the left side wall 6D to suppress the vibration of the left side wall 6D of the front case 6, and can suppress the noise radiated from the transmission case 4.

[0086] Further, according to the sound insulation structure of the transmission 2 of the present embodiment, the resin cover 16A has an extending portion 16C, and the extending portion 16C extends downward from the resin cover 16A below the lower end portion 16f of the sound absorbing member 16B and covers the sound absorbing member 16B from below.

[0087] Thereby, when foreign matters (such as small stones and snow) on the road surface are bounced up during the running of the vehicle 1, the foreign matters can be prevented from colliding with the resin cover 16A, so that the foreign matters can be prevented from contacting the sound absorbing member 16B and the sound absorbing member 16B can be protected.

[0088] In particular, when snow penetrates into the sound absorbing member 16B during running in winter or the like, the sound absorbing member 16B is likely to freeze and be damaged. Therefore, snow can be shielded by the resin cover 16A to prevent it from adhering to the sound absorbing member 16B. For this reason, freezing of the sound absorbing member 16B and the like can be suppressed, and the sound absorbing member 16B can be reliably protected.

[0089] Further, according to the sound insulation structure of the transmission 2 of the present embodiment, the transmission case 4 includes a front case 6 having a front flange portion 6A provided at the front end portion and a rear flange portion 6B provided at the rear end portion, a torque converter housing 5 located in front of the front case 6 and having a rear end connected to the front flange portion 6A, and a transfer front case 7 located behind the front case 6 and having a front end connected to the rear flange portion 6B.

[0090] The upper bulging portion 16a and the lower bulging portion 16b extend from the front flange portion 6A to the rear flange portion 6B of the front case 6. The sound-absorbing member 16B has a front end portion 16c that abuts against the front flange portion 6A between the horizontal ribs 6F and 6G, and a rear end portion 16d that abuts against the rear flange portion 6B between the horizontal ribs 6F and 6G.

[0091] Thereby, the elastic force of the sound-absorbing member 16B can strongly press and adhere the front end portion 16c of the sound-absorbing member 16B against the front flange portion 6A, and the rear end portion 16d of the sound-absorbing member 16B can be strongly pressed and adhered against the rear flange portion 6B.

[0092] Therefore, the gap between the front flange portion 6A and the front end portion 16c of the sound-absorbing member 16B made of urethane rubber, and the gap between the rear flange portion 6B and the rear end portion 16d of the sound-absorbing member 16B made of urethane rubber can be reduced, and the airtightness of the space 17 can be further enhanced. As a result, the noise radiated from the transmission case 4 can be more effectively suppressed.

[0093] Also, according to the sound insulation structure of the transmission 2 of the present embodiment, vertical ribs 6H, 6I, 6J for reinforcing the front case 6 are provided on the left side wall 6D of the front case 6.

[0094] The vertical ribs 6H, 6I, 6J extend in the vertical direction and project in the left-right direction from the left side wall 6D, connecting the horizontal ribs 6E and 6F. The sound-absorbing member 16B abuts against the tips of the vertical ribs 6H, 6I, 6J in the protruding direction.

[0095] Thereby, the vertical ribs 6H, 6I, 6J can be reinforced by the sound-absorbing member 16B, and the vibration of the left side wall 6D of the front case 6 can be more effectively suppressed. As a result, the noise radiated from the transmission case 4 can be suppressed.

[0096] Note that the sound-absorbing 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 attachment sites to the transmission case 4.

[0097] Also, even for the sound-absorbing members of the same sound insulation cover, urethane materials may be selected according to the frequency band of the radiated sound generated from the attachment sites to the transmission case 4. For example, the upper part and the lower part of the sound-absorbing member 16B of the left sound insulation cover 16 may be divided into urethane materials according to the frequency band of the radiated sound.

[0098] 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

[0099] 2 Transmission (vehicle transmission) 5 Torque converter housing (transmission case, front case) 6 Front case (transmission case, intermediate case) 6A Front flange portion 6B Rear flange portion 6D Left side wall (side wall) 6F Horizontal rib (upper horizontal rib) 6G Horizontal rib (lower horizontal rib) 6H, 6I, 6J Vertical ribs 7 Transfer front case (transmission case, rear case) 16 Left sound insulation cover (sound insulation cover) 16A Resin cover 16a Upper bulging portion 16B Sound-absorbing member 16b Lower bulging portion 16C Extended portion 16c Front end portion (front contact portion) 16d Rear end portion (rear contact portion) 16f Lower end portion (lower end portion of the sound-absorbing member)

Claims

1. A transmission case and a sound insulation cover attached to a side wall of the transmission case, wherein the transmission case has a pair of lateral ribs extending in the front-rear direction of the side wall and protruding from the side wall in the left-right direction to reinforce the transmission case, and the pair of lateral ribs includes an upper lateral rib and a lower lateral rib disposed below the upper lateral rib, and the sound insulation structure of a vehicle transmission is provided, wherein the sound insulation cover includes a resin cover and a sound absorption member provided integrally with the resin cover between the side wall and the resin cover and having a lower rigidity than the resin cover, wherein the sound absorption member is disposed above the upper lateral rib and has an upper bulging portion that abuts against the upper surface of the upper lateral rib in the vertical direction, and is disposed below the lower lateral rib and has a lower bulging portion that abuts against the lower surface of the lower lateral rib in the vertical direction, and the sound insulation structure of a vehicle transmission is characterized by this.

2. The resin cover has an extension portion, wherein the extension portion extends downward from the resin cover below the lower end portion of the sound absorption member and covers the sound absorption member from below, and the sound insulation structure of a vehicle transmission according to claim 1 is characterized by this.

3. The transmission case includes an intermediate case having a front flange portion provided at a front end portion and a rear flange portion provided at a rear end portion, a front case located in front of the intermediate case and having a rear end portion connected to the front flange portion, and a rear case located behind the intermediate case and having a front end portion connected to the rear flange portion, wherein the upper lateral rib and the lower lateral rib are provided on the intermediate case, wherein the upper bulging portion and the lower bulging portion extend from the front flange portion to the rear flange portion, wherein the sound absorption member has a front contact portion that abuts against the front flange portion between the upper lateral rib and the lower lateral rib, and a rear contact portion that abuts against the rear flange portion between the upper lateral rib and the lower lateral rib, and the sound insulation structure of a vehicle transmission according to claim 1 or claim 2 is characterized by this.

4. A vertical rib for reinforcing the transmission case is provided on the side wall, wherein the vertical rib extends in the vertical direction and protrudes from the side wall in the left-right direction to connect the upper lateral rib and the lower lateral rib, and the sound absorption member abuts against the tip of the vertical rib in the protruding direction, and the sound insulation structure of a vehicle transmission according to claim 1 or claim 2 is characterized by this.

5. A vertical rib for reinforcing the transmission case is provided on the side wall, the vertical rib extends in the vertical direction and protrudes in the left-right direction from the side wall, connecting the upper horizontal rib and the lower horizontal rib, The sound absorption member abuts against the tip in the protruding direction of the vertical rib. The sound insulation structure of the vehicle transmission according to claim 3, characterized in that.

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