JP7123507B2 - transmission - Google Patents

Description

The present invention relates to a transmission mounted on a vehicle such as an automobile.

A manual transmission (MT) is widely known as a transmission mounted on a vehicle such as an automobile.

A manual transmission has an input shaft and an output shaft that are arranged parallel to each other. The input shaft and the output shaft are rotatably supported by a unit case forming the outer shell of the manual transmission. In the unit case, a drive gear and a set of driven gears meshing with the drive gear are provided for each forward speed. The drive gear of each shift stage is formed integrally with the input shaft, supported so as not to rotate relative to the input shaft, or supported so as to rotate relative to the input shaft. The driven gear of each gear is formed integrally with the output shaft or supported so as not to rotate relative to it, or supported so as to rotate relative to the input shaft.

The end of the output shaft is rotatably supported by the unit case via ball bearings. The inner race (inner ring) of the ball bearing is fitted onto the end of the output shaft. The unit case is formed with a facing wall portion facing the end surface of the output shaft and a peripheral wall portion surrounding the end portion of the output shaft with a space therebetween. An outer race (outer ring) of the ball bearing is arranged inside the peripheral wall and is retained with respect to the peripheral wall by a snap ring.

Since the opposing wall faces the ball bearing in the direction of the rotation axis, a service hole may be formed in the opposing wall in order to enable the snap ring to be operated from the outside of the unit case.

Japanese Patent Application Laid-Open No. 2008-303981

However, depending on the formation position of the service hole, there is a concern that problems such as breakage of members inside the unit case may occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transmission capable of suppressing the occurrence of various problems caused by the formation of service holes.

In order to achieve the above object, the transmission according to the present invention is a transmission mounted on a vehicle, comprising: a unit case; a shaft rotatably supported by the unit case via bearings; The unit case has a facing wall facing the end surface on one side of the shaft, and a peripheral wall portion surrounding the end on the one side of the shaft with a gap from the peripheral surface, The inner race of the bearing is fitted onto the shaft, the outer race of the bearing is arranged inside the peripheral wall and is retained by a snap ring against the peripheral wall. The snap ring can be accessed from the outside of the unit case by straddling the facing wall and the peripheral wall at the position on the upstream side in the direction of the force acting on the shaft due to the force received by the gear when the vehicle is traveling forward. A service hole is formed.

According to this configuration, one end of the shaft is rotatably supported by the unit case via the bearing. The inner race (inner ring) of the bearing is fitted onto the end of the shaft. The unit case is formed with a facing wall portion facing the end face of the shaft and a peripheral wall portion surrounding the end of the shaft with a space therebetween. An outer race (outer ring) of the ball bearing is arranged inside the peripheral wall and is retained with respect to the peripheral wall by a snap ring.

A service hole is formed in the unit case. The service hole is positioned on the upstream side of the center of the shaft in the direction of the force acting on the shaft due to the force received by the gear when the vehicle is traveling forward. shaped to allow access to the snap ring from the outside of the As a result, when the vehicle travels forward, it is possible to prevent the outer race of the bearing from biting into the notched portion formed by forming the service hole in the peripheral wall portion. Therefore, damage to the outer race and the peripheral wall due to the outer race biting into the notch portion can be suppressed. In addition, it is possible to suppress the inclination of the shaft due to the outer race biting into the notch portion of the peripheral wall portion.

According to the present invention, it is possible to suppress the occurrence of various problems due to the formation of service holes.

1 is a cross-sectional view showing the configuration of a transmission unit according to one embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view showing the configuration near the end of the output shaft; FIG. 4 is a side view of the transmission unit viewed from the side opposite to the engine side, showing a state in which the service hole is closed with a service hole plug; FIG. 4 is a side view of the transmission unit viewed from the side opposite to the engine side, showing a state in which the service hole is opened; It is the side view which looked at the transmission unit from the side opposite to the engine side, and shows the structure from which the formation position of a service hole differs.

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Structure of transmission unit>
FIG. 1 is a cross-sectional view showing the configuration of a transmission unit 1 according to one embodiment of the invention. In addition, in FIG. 1, the hatching representing the cross section is omitted.

The transmission unit 1 adopts the form of a transaxle having a transmission 3 and a differential gear 4 in a unit case 2 forming an outer shell of the transmission unit 1 . The transmission unit 1 is mounted on a vehicle using an engine (not shown) as a drive source, and the power of the engine is changed by the transmission 3, and the changed power is sent to the left and right driving wheels via the differential gear 4. introduce. Oil is enclosed in the unit case 2 .

The transmission 3 is a manual transmission (MT) having five forward gears and one reverse gear, and is arranged on one side in the vehicle width direction with respect to the engine in the engine compartment of the vehicle. The transmission 3 includes an input shaft 11 extending in the vehicle width direction and an output shaft 12 arranged parallel to the input shaft 11 .

The engine-side end of the input shaft 11 passes through the unit case 2 and is connected to a clutch mechanism (not shown) outside the unit case 2 . The power of the engine is input to the input shaft 11 via a clutch mechanism. An engine-side end of the input shaft 11 in the unit case 2 is rotatably supported by the unit case 2 via a ball bearing 13 . On the other hand, the end of the input shaft 11 opposite to the engine side is rotatably supported by the unit case 2 via a ball bearing 14 .

A first-speed drive gear 21, a reverse drive gear 22, and a second-speed drive gear 23 are integrally formed on the input shaft 11 in order from the engine side. Further, on the input shaft 11, a 3rd speed drive gear 24, a 4th speed drive gear 25 and a 5th speed drive gear 26 are arranged in order from the 2nd speed drive gear 23 side on the side opposite to the engine side with respect to the 2nd speed drive gear 23. Each is supported so as to be relatively rotatable.

The engine-side end of the output shaft 12 is rotatably supported by the unit case 2 via a needle bearing 27 inside the unit case 2 . On the other hand, an end portion 81 of the output shaft 12 opposite to the engine side is rotatably supported by the unit case 2 via a ball bearing 28 inside the unit case 2 . A support structure for the end portion 81 of the output shaft 12 will be detailed later.

An output gear 31 is integrally formed at the engine-side end of the output shaft 12 . A first-speed driven gear 32, a reverse driven gear 33, and a second-speed driven gear 34 are rotatably supported in order from the output gear 31 on the output shaft 12 on the opposite side of the output gear 31 from the engine side. ing. Furthermore, a third driven gear 35, a fourth driven gear 36, and a fifth driven gear 37 are spline-fitted to the output shaft 12 in order from the second driven gear 34 side on the side opposite to the engine side with respect to the second driven gear 34. It is supported so as not to rotate relative to it.

The 1st-speed driven gear 32 is always in mesh with the 1st-speed drive gear 21 , and the 2nd-speed driven gear 34 is always in mesh with the 2nd-speed drive gear 23 . In addition, the 3rd speed driven gear 35 is always meshed with the 3rd speed drive gear 24, the 4th speed driven gear 36 is always meshed with the 4th speed drive gear 25, and the 5th speed driven gear 37 is always meshed with the 5th speed drive gear 26. there is

A reverse idler shaft 41 is arranged in parallel with the input shaft 11 and the output shaft 12 in the unit case 2 . The engine-side end of the reverse idler shaft 41 is inserted into a recess 42 formed in the unit case 2 . A bolt insertion hole 43 is formed through the unit case 2 at a position opposed to the end of the reverse idler shaft 41 opposite to the engine side from above. A bolt 44 is inserted into the bolt insertion hole 43 from the outside of the unit case 2 . By screwing the tip of the bolt 44 into a fixing hole 45 formed in the reverse idler shaft 41 , the reverse idler shaft 41 is non-rotatably fixed to the unit case 2 .

A reverse idler gear 46 is supported on the reverse idler shaft 41 so as to be relatively rotatable and movable in the rotation axis direction. The reverse idler gear 46 is displaced between a meshing position where it meshes with both the reverse drive gear 22 and the reverse driven gear 33 and a non-engaging position where it disengages from the meshing with the reverse drive gear 22 and the reverse driven gear 33 .

A 1st-2nd speed synchromesh (hub assembly) 51 is provided between the 1st speed driven gear 32 and the 2nd speed driven gear 34 . The 1st-2nd speed synchromesh 51 has a known structure, and includes a synchronizer hub 52 spline-fitted to the output shaft 12, synchronizer rings 53 arranged on both sides of the synchronizer hub 52, and sleeves surrounding the outer periphery of the synchronizer hub 52. 54, etc. The inner peripheral surface of the sleeve 54 is spline-fitted with the outer peripheral surface of the synchro hub 52 , and the sleeve 54 rotates integrally with the synchro hub 52 and the output shaft 12 . The reverse driven gear 33 is formed integrally with the sleeve 54 .

A 3rd-4th speed synchromesh 55 is provided between the 3rd speed drive gear 24 and the 4th speed drive gear 25 . A fifth-speed synchromesh 56 is provided on the opposite side of the fifth-speed drive gear 26 from the engine side. Since the configurations of the 3rd-4th speed synchromesh 55 and the 5th speed synchromesh 56 are well known, the description thereof will be omitted.

When the shift lever is moved to the 1st speed position by the select operation and the shift operation of the shift lever provided in the vehicle compartment, the 1st speed driven gear 32 is shifted to the output shaft 12 by the function of the 1st-2nd speed synchromesh 51. are non-rotatably coupled to the As a result, power input to the input shaft 11 is transmitted to the output shaft 12 via the 1st speed drive gear 21 and the 1st speed driven gear 32 . At this time, the power of the engine is changed at the gear ratio of the first gear and transmitted to the output shaft 12 .

When the shift lever is moved to the 2nd speed position, the 1st-2nd speed synchromesh 51 functions to couple the 2nd speed driven gear 34 to the output shaft 12 so as not to rotate relative to it. As a result, power input to the input shaft 11 is transmitted to the output shaft 12 via the 2nd speed drive gear 23 and the 2nd speed driven gear 34 . At this time, the power of the engine is changed at the gear ratio of the second gear and transmitted to the output shaft 12 .

When the shift lever is moved to the 3rd speed position, the 3rd-4th speed synchromesh 55 functions to couple the 3rd speed drive gear 24 to the input shaft 11 so as not to rotate relative to it. As a result, the power input to the input shaft 11 is transmitted to the output shaft 12 via the 3rd speed drive gear 24 and the 3rd speed driven gear 35 . At this time, the power of the engine is changed at the gear ratio of the third speed stage and transmitted to the output shaft 12 .

When the shift lever is moved to the 4th speed position, the 3rd-4th speed synchromesh 55 functions to couple the 4th speed drive gear 25 to the input shaft 11 so as not to rotate relative to it. As a result, power input to the input shaft 11 is transmitted to the output shaft 12 via the 4th speed drive gear 25 and the 4th speed driven gear 36 . At this time, the power of the engine is shifted at the gear ratio of the fourth speed stage and transmitted to the output shaft 12 .

When the shift lever is set to the fifth speed position, the fifth speed synchromesh 56 functions to couple the fifth speed drive gear 26 to the input shaft 11 so as not to rotate relative to it. As a result, power input to the input shaft 11 is transmitted to the output shaft 12 via the fifth speed drive gear 26 and the fifth speed driven gear 37 . At this time, the power of the engine is shifted at the gear ratio of the fifth gear and transmitted to the output shaft 12 .

When the shift lever is placed in the reverse position, the shift and select shaft moves in the axial direction and the circumferential direction along with the select operation and shift operation of the shift lever, and the reverse shift fork moves, thereby rotating the reverse idler gear 46. It is displaced to a position where it meshes with the reverse drive gear 22 and the reverse driven gear 33 . At this time, the power input to the input shaft 11 is transmitted to the output shaft 12 via the reverse drive gear 22 , the reverse idler gear 46 and the reverse driven gear 33 . As a result, the output shaft 12 rotates in a direction opposite to that in the 1st-5th gear.

The differential gear 4 has a differential case 61 . The differential case 61 has a gear housing portion 63 that provides a gear housing space 62 inside, and a flange portion 64 that protrudes from the outer periphery of the gear housing portion 63 in the radial direction of rotation.

A pinion shaft 65 extending in the radial direction of rotation is held in the gear housing portion 63 so as to pass through the gear housing space 62 . Two pinion gears 66 and 67 are rotatably held on the pinion shaft 65 with a space therebetween. Two side gears 68 and 69 are arranged separately on both sides of the pinion shaft 65 in the gear housing space 62 . Both the side gears 68, 69 and the pinion gears 66, 67 are bevel gears, and each side gear 68, 69 meshes with both the pinion gears 66, 67.

The gear housing portion 63 is formed with cylindrical shaft insertion portions 71 and 72 penetrating in the direction in which the side gears 68 and 69 face each other, in other words, in the direction orthogonal to the pinion shaft 65 . Drive shafts (not shown) are inserted into the shaft insertion portions 71 and 72 from the outside of the differential case 61 . The tip of the drive shaft is coupled to side gears 68 and 69 in the gear housing space 62 so as not to rotate relative to each other.

Bearings 73 and 74 are fitted onto the shaft insertion portions 71 and 72, respectively. Outer races (outer rings) of the bearings 73 and 74 are non-rotatably held by the unit case 2 . Thereby, the differential case 61 is rotatably supported by the unit case via bearings 73 and 74 about the same rotation axis as the drive shaft.

A ring gear 75 is fixed to the flange portion 64 . The ring gear 75 integrally has a substantially annular plate-shaped web 76 surrounding the differential case 61 and a substantially cylindrical rim 77 surrounding the outer periphery of the web 76 . The rim 77 protrudes from the web 76 to both sides in the direction along the rotation axis of the differential case 61 . Gear teeth are formed on the outer peripheral surface of the rim 77 and mesh with the output gear 31 of the transmission 3 .

Power transmitted to the output shaft 12 of the transmission 3 is transmitted from the output gear 31 to the ring gear 75 . As a result, the ring gear 75 and the differential case 61 rotate together. Rotation of the differential case 61 is converted to rotation of side gears 68 and 69 via pinion gears 66 and 67 . As a result, the drive shaft rotates integrally with the side gears 68 and 69, and the rotation of the drive shaft is transmitted to the drive wheels of the vehicle.

In addition, since oil is sealed in the unit case 2, when the ring gear 75 and the differential case 61 rotate together, the oil accumulated at the bottom of the unit case 2 is scraped up by the ring gear 75 and the differential case 61 and splashes. As a result, oil droplets are supplied to each part in the unit case 2 .

<Main part configuration>
FIG. 2 is a sectional view showing the configuration near the end 81 of the output shaft 12. As shown in FIG. Also in FIG. 2, the hatching representing the cross section is omitted.

The unit case 2 includes a facing wall portion 83 facing the end face 82 of the end portion 81 of the output shaft 12 on the side opposite to the engine side from the rotation axis direction of the output shaft 12 , and an outer peripheral surface of the end portion 81 . and a surrounding wall portion 84 are formed.

An inner race (inner ring) 85 of the ball bearing 28 is fitted onto the end portion 81 of the output shaft 12 . An outer race (outer ring) 86 of the ball bearing 28 is arranged inside the peripheral wall portion 84 and is secured to the peripheral wall portion 84 by a snap ring 87 .

3 and 4 are side views of the transmission unit 1 viewed from the side opposite to the engine side.

A service hole 88 is formed in the unit case 2 . The service hole 88 is formed so that the 1st driven gear 32, the 2nd driven gear 34, the 3rd driven gear 35, the 4th driven gear 36 and the 5th driven gear 37 are aligned with the center of the output shaft 12 when the vehicle is traveling forward. 21, the direction of the force acting on the output shaft 12 due to the force received from the 2nd speed drive gear 23, the 3rd speed drive gear 24, the 4th speed drive gear 25 and the 5th speed drive gear 26 (the direction indicated by the white arrow in FIG. 3) is formed at a position on the upstream side of the . 2, the service hole 88 is formed across the opposing wall portion 83 and the peripheral wall portion 84 so as to allow access to the snap ring 87 from the outside of the unit case 2. ing.

Service hole 88 is always closed by a service hole plug 89 as shown in FIG. By extracting the service hole plug 89 from the service hole 88, the service hole 88 is opened, and access to the snap ring 87 through the service hole 88 becomes possible.

<Effect>
As described above, the service hole 88 is located on the upstream side in the direction of the force acting on the output shaft 12 when the vehicle is traveling forward, that is, in the direction indicated by the white arrow in FIG. formed in position.

A service hole 88, which allows access to the snap ring 87 from outside the unit case 2, acts on the output shaft 12 when the vehicle is traveling forward, relative to the center of the output shaft 12, as shown in FIG. It can also be formed at a downstream position in the direction of the applied force (the direction indicated by the white arrow in FIG. 3). However, in the configuration shown in FIG. 5, the outer race 86 of the ball bearing 28 bites into the notched portion formed by the service hole 88 in the peripheral wall portion 84 when the vehicle travels forward. This biting may cause the outer race 86 to be deformed and cracked, or the peripheral edge of the notched portion of the peripheral wall portion 84 to be damaged.

On the other hand, in the configuration in which the service hole 88 is formed on the upstream side of the center of the output shaft 12 in the direction of the force acting on the output shaft 12 during forward travel, the peripheral wall portion 84 is It is possible to prevent the outer race 86 of the ball bearing 28 from biting into the notched portion formed by forming the service hole 88 . Therefore, damage to the outer race 86 and the peripheral wall portion 84 due to the outer race 86 biting into the notch portion can be suppressed. In addition, tilting of the output shaft 12 due to the outer race 86 biting into the cutout portion of the peripheral wall portion 84 can be suppressed, and various problems caused by the tilting of the output shaft 12 can be suppressed.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, in the above-described embodiment, the transmission 3 is a manual transmission, but the present invention may be a continuously variable transmission (CVT) or a stepped automatic transmission (AT). etc., can be widely applied.

Further, the shaft to which the present invention is applied is not limited to the output shaft 12 as long as it is a shaft provided in a transmission.

In addition, various design changes can be made to the above configuration within the scope of the matters described in the claims.

2: Unit case 3: Transmission 12: Output shaft 28: Ball bearing 35: 3rd speed driven gear (gear)
36: 4th speed driven gear (gear)
37: 5-speed driven gear (gear)
81: End 82: End face 83: Opposing wall 84: Peripheral wall 86: Outer race 87: Snap ring 88: Service hole

Claims (1)

A transmission mounted on a vehicle,
unit case and
a shaft rotatably supported by the unit case via a bearing;
a gear that rotates integrally with the shaft,
The unit case has a facing wall portion facing one end surface of the shaft, and a peripheral wall portion surrounding the one end of the shaft with a gap therebetween,
an inner race of the bearing is fitted onto the shaft,
The outer race of the bearing is arranged inside the peripheral wall portion and is retained by a snap ring against the peripheral wall portion,
In the unit case, at a position on the upstream side of the center of the shaft in the direction of the force acting on the shaft due to the force received by the gear when the vehicle travels forward, A service hole is formed across the unit case to enable access to the snap ring from the outside of the unit case ,
The transmission , wherein the center of the service hole is shifted upstream in the direction of the force with respect to the center of the shaft .

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