JPH05272603A - Reverse mechanism for gear transmission - Google Patents

Abstract

PURPOSE:To provide a reverse mechanism for a gear transmission, in which a smooth reverse shift is possible, without lengthening a shaft length and providing retreat exclusive gears on an input and an output shafts. CONSTITUTION:A first speed gear 6, fixedly provided on an input shaft 2, is engaged with a first idler gear 31, and a second idler gear 32 is engaged with a third speed gear 17, fixedly provided on an output shaft 3. The first and the second idler gears 31 and 32 are selectively connected to a retreating synchronizer 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reverse mechanism of a gear transmission.

[0002]

2. Description of the Related Art Conventionally, as a reverse mechanism of a gear transmission, an idler shaft parallel to an input shaft and an output shaft is provided, and an idler gear is provided on the shaft so as to be movable in the axial direction, and a reverse input gear is provided on the input shaft. It is known that a reverse output gear is integrally provided on the sleeve of the 1-2 speed switching synchronizer of the output shaft (actually developed 64-218).
42 publication). In this case, in the forward stage, the idler gear should be disengaged from the reverse input gear and the reverse output gear, and when the reverse stage is obtained, the idler gear should be shifted in the axial direction so that the reverse input gear and the reverse output gear should not be moved. Are biting together.

However, in such a gear transmission, since the reverse mechanism is a selectively meshing type, when the idler gear and the chamfer ridge lines of the reverse input gear and the reverse output gear contact each other during the reverse shift, the head of the gear changes. There is a risk of causing a thrust and becoming unable to shift. Further, when a shift operation is performed to the reverse gear while the vehicle is not completely stopped, gear noise may occur because the input shaft or the output shaft is rotating.

[0004]

In order to solve such a problem, there has been proposed a gear transmission in which the reverse mechanism is a constant mesh type and a synchronous type, and the head butt and gear squeal of gears are eliminated (actually, the gear transmission). (Kaihei 2-60747). This transmission has a reverse input gear fixed on the input shaft, a reverse output gear fixed on the output shaft, and a first idler gear that always meshes with the reverse input gear and a reverse output on the idler shaft. A second idler gear that constantly meshes with the gear is rotatably provided. Then, by connecting the first idler gear and the second idler gear with a synchronizer,
You're getting back.

In this case, however, not only the input shaft but also the output shaft must be provided with a reverse gear, so that the number of gears increases and not only the weight increases, but also the axial length of the transmission is increased. It has the drawback of being long. In particular, it is not a preferable structure for a transmission whose axial dimension is severely restricted, such as a transmission for an FF vehicle.

There is also a FR vehicle transmission which is provided with a constantly meshing reverse mechanism in the same manner as described above (Japanese Utility Model Laid-Open No. 1-148143). In this case as well, similarly to the above, it is necessary to provide the reverse gears on the input shaft and the output shaft, which has the drawbacks of increasing the shaft length and increasing the number of parts. Therefore, an object of the present invention is to provide a reverse mechanism of a gear transmission that can smoothly perform a reverse shift without increasing the shaft length and without providing a reverse gear only on the input shaft and the output shaft. ..

[0007]

In order to achieve the above object, the present invention provides a first shaft on the input side, a second shaft on the output side parallel to the first shaft, and a first shaft. First gear installed,
A second gear rotatably supported on the second shaft and constantly meshing with the first gear, a third gear rotatably supported on the first shaft, and a third gear fixed to the second shaft. A forward gear synchronizer that selectively connects the second gear to the second shaft or the third gear to the first shaft, and the first gear and the second gear. , And a third gear and a fourth gear are respectively arranged in parallel to the first shaft and the second shaft in a gear transmission that constitutes a forward speed change gear pair,
A first idler gear that constantly meshes with the first gear;
A second idler gear that is coaxially and relatively rotatably arranged with respect to the idler gear and always meshes with the fourth gear, and a reverse synchronizing device that selectively connects the first and second idler gears. ..

[0008]

In the reverse operation, that is, when the first idler gear and the second idler gear are connected by the reverse synchronizer, the second gear idles on the second shaft and the third gear idles on the first shaft. Therefore, the driving force of the first shaft is sequentially transmitted to the first gear, the first idler gear, the second idler gear, and the fourth gear, and the second shaft rotates in the direction opposite to the forward direction.

As described above, since the reverse gear is obtained by utilizing the forward speed change gear, it is not necessary to provide the reverse gears for the first shaft and the second shaft, and it is not necessary to extend the axial length. Further, since the first idler gear and the first gear, and the second idler gear and the fourth gear are always meshed with each other, no ringing of the gear or head bump occurs, and moreover, since they are switched by the synchronizing device,
A smooth reverse shift is possible. Furthermore, since there are only two reverse gears, the first idler gear and the second idler gear, the number of gears is minimized, and the transmission can be made smaller and lighter.

Further, conventionally, since a spur gear is generally used as the reverse gear, there is a drawback that the noise during the backward movement is larger than that during the forward movement. On the other hand, in the present invention, when helical gears are used for the first to fourth gears, which are forward transmission gears, helical gears are also used for the first idler gear that meshes with the second gear and the second idler gear that meshes with the third gear. Therefore, it is possible to obtain the same quietness when moving backward as when moving forward.

In the present invention, in order to obtain a desired reduction gear ratio at the time of reverse, the gear stage constituted by the first gear and the second gear is set at a lower speed than the gear stage constituted by the third gear and the fourth gear. It is desirable to set the ratio side. Generally, the speed reduction ratio during reverse is set to a value close to the speed reduction ratio of the first forward speed, but if the speed change stage configured by the first gear and the second gear is set to the third gear and the fourth gear.
This is because if the speed ratio side is set to be higher than the speed ratio configured with the gears, the speed reduction ratio at the time of retreat becomes a value considerably smaller than the speed reduction ratio of the first speed. Further, it is desirable that the first gear is a gear that is long in the axial direction so that the meshing portion of the first gear with the second gear and the meshing portion of the first idler gear are offset in the axial direction. The reason is that if the second gear and the first idler gear mesh with the same portion of the first gear,
This is because the idler gear and the second gear interfere with each other and cannot rotate with each other.

The term "fixed" in the present invention includes not only the case where the gear is integrally formed on the shaft, but also the case where the gear which is separate from the shaft is connected to the shaft so as to be integrally rotatable by a spline or the like. Further, the synchronizer in the present invention is provided with a mechanism for reducing the rotational speed difference of the dog clutch in order to avoid shocking engagement, and may be of any type such as constant road type, inertia lock type, servo type. May be.

[0013]

1 and 2 show an example of a laterally mounted transmission for an FF vehicle having a shift speed of 5 forward speeds and 1 reverse speed according to the present invention. An input shaft (first shaft) 2 and an output shaft (second shaft) 3 are arranged in parallel inside the case 1 and are rotatably supported. The input shaft 2 is driven by the engine through a clutch, and its front end side (right side in FIG. 1)
A first speed gear 6 and a second speed gear 7 are fixedly installed in the.
Further, a third speed gear 8, a fourth speed gear 9, and a fifth speed gear 10 are rotatably supported on the rear end side of the input shaft 2.
The high speed gear 8 and the fourth speed gear 9 are the synchronizing device 1 for switching between the third speed and the fourth speed.
1 is selectively connected to the input shaft 2. The fifth speed gear 10 is selectively connected to the input shaft 2 by the fifth speed switching synchronizer 12.

An output gear 13 is fixedly provided on the front end side of the output shaft 3, and a first speed gear 14 and a second speed gear 15 are rotatably mounted on the output shaft 3 adjacent to the output gear 13. The gears 14 and 15 are selectively connected to the output shaft 3 by a 1st-2nd speed switching synchronizer 16.
The first speed gear 14 is always in mesh with the first speed gear 6 on the input shaft 2, and the second speed gear 15 is always in mesh with the second speed gear 7 on the input shaft 2. On the rear end side of the output shaft 3, the third speed gear 17, the fourth speed gear 18, and the fifth speed gear 18, which are in constant mesh with the third speed gear 8, the fourth speed gear 9, and the fifth speed gear 10, respectively, on the input shaft 2. The high speed gear 19 is fixed. Output gear 1 of output shaft 3
3 is engaged with the ring gear 21 of the differential device 20,
The driving force is distributed to the left and right axles 22 and 23.

Inside the case 1, an idler shaft 30 is arranged in parallel with the input shaft 2 and the output shaft 3, and a first idler gear 31 and a second idler gear 3 are disposed on the shaft 30.
2 and 2 are rotatably supported. And both gears 3
A backward synchronizing device 33 for selectively connecting the two is provided between the first and second devices. The first idler gear 31 is the second
The diameter of the gear is larger than that of the idler gear 32. The first idler gear 31 always meshes with the first speed gear 6 of the input shaft 2, and the second idler gear 32 always meshes with the third speed gear 17 of the output shaft 3. The first speed gear 6 of the input shaft 2 is a gear long in the axial direction, and the first idler gear 31
The meshing portion between the gear and the first speed gear 14 of the output shaft 3 is offset in the axial direction. As a result, the interference between the first idler gear 31 and the first speed gear 14 is prevented. It should be noted that not only the first to fifth speed gears for forward movement and the output gear 13 but also the first and second idler gears 31 and 32 are configured by helical gears.

The operation of the gear transmission having the above structure will be described below. When traveling forward, the first-second speed switching synchronization device 16, the third-fourth speed switching synchronization device 11 or the fifth-speed switching synchronization device 12 is alternatively operated. For example, when the 1st-2nd speed switching synchronizer 16 is switched to the 1st speed side, the 1st speed gear 14 is connected to the output shaft 3. Therefore, the driving force of the input shaft 2 is the first speed gears 6, 14
Is transmitted to the output shaft 3 via the output gear 13 and is transmitted to the ring gear 21 of the differential device 20.
Can be driven forward. Since the first idler gear 31 meshes with the first speed gear 6 of the input shaft 3, it rotates in the opposite direction to the input shaft 2, but the second idler gear 32 meshes with the third speed gear 17 of the output shaft 3. Therefore, it rotates in the same direction as the input shaft 2. That is, the first idler gear 31 and the second idler gear 32 idle in opposite directions. When traveling in reverse, the reverse synchronizer 33 is shifted to the left in FIG. 1, and the first and second idler gears 31,
32 are connected to each other. At this time, the forward synchronization device 1
Since gears 1, 12 and 16 are in the neutral position, gears 14 and 8 are idling. Therefore, the driving force of the input shaft 2 is transmitted from the first speed gear 6 to the first idler gear 31, and further from the second idler gear 32 to the third speed gear 17 to the output shaft 3
Is transmitted to. Then, from the output gear 13 to the differential device 2
It is transmitted to the ring gear 21 of 0, and the axles 22 and 23 can be driven backward.

In the case of the reverse mechanism of the above-mentioned embodiment, like the selective mesh type reverse mechanism as disclosed in Japanese Utility Model Laid-Open No. 64-21842, the synchronizing device 16 for switching between the first and second speeds is used.
Since it is not necessary to form the reverse gear in the sleeve of the above, the axial size of the synchronizing device 16 itself can be shortened. for that reason,
It is possible to shorten the shaft length of the transmission. In addition, the first and second idler gears 31, 32 are different from those of the conventional transmission.
If the idler shaft 30 is changed, the other parts, that is, the input shaft 2, the output shaft 3, the first to fifth speed gears, etc. can be shared by the conventional parts, so that a large design change is unnecessary. Can be constructed at low cost.

FIG. 3 shows a second embodiment of the present invention. This embodiment is a vertical gear transmission for an FR vehicle, which has a forward movement of 5
It has a first speed and a reverse speed, and the fourth speed is directly connected. The input shaft (first shaft) 40 and the output shaft (third shaft) 41 are arranged adjacent to each other on the same axis line, and the input shaft 40 is longer than the output shaft 41. In addition, parallel to these axes 40 and 41, the auxiliary axis (second
The shaft 42 is arranged. A first speed gear 43 and a second speed gear 44 are fixedly provided at the center of the input shaft 40. A fifth speed gear 45 and a third speed gear 46 are rotatably supported on the rear end portion of the input shaft 40, and the fifth speed gear 4
The fifth gear 5 is selectively connected to the input shaft 40 by the fifth speed switching synchronizer 47.

A final reduction gear 48 is fixedly mounted on the front end of the output shaft 41, and between the front side of the final reduction gear 48, that is, between the rear end of the input shaft 40 and the front end of the output shaft 41. , Third
There is provided a third-to-fourth speed switching synchronizing device 49 for selectively connecting the high speed gear 46 or the output shaft 41 to the input shaft 40. The rear end of the output shaft 41 is connected to the wheels via a drive shaft (not shown). The first speed gear 43 and the second speed gear 4 of the input shaft 40 are provided at the front end of the sub shaft 42.
4, a first speed gear 50 and a second speed gear 51, which mesh with 4 respectively.
Is rotatably supported, and is provided with a first-to-second speed switching synchronizing device 52 which selectively connects both gears 50 and 51 to the auxiliary shaft 42. Further, a fifth speed gear 53 and a third speed gear 54 that mesh with the fifth speed gear 45 and the third speed gear 46, respectively, are fixedly provided in the center of the sub shaft 42,
Further, at the rear end of the auxiliary shaft 42, the final reduction gear 4 of the output shaft 41
The final reduction gear 55 that meshes with the gear 8 is fixed.

An idler shaft 60 is arranged in parallel to the side portion of the input shaft 40, and a first idler gear 61 and a second idler gear 62 are rotatably supported on the idler shaft 60. A reverse synchronizing device 63 is provided between the gears 61 and 62 to selectively connect the two. The diameter of the first idler gear 61 is larger than that of the second idler gear 62.
No. 0 first speed gear 43 always meshes, and second idler gear 62 always meshes with sub shaft 42 third speed gear 54. Also in this case, as in the first embodiment, the first speed gear 43 is composed of a gear having a long axial length, and the meshing part with the first idler gear 61 and the meshing part with the first speed gear 50 are the shafts. Offset in the direction.

The above components are housed in a case 70, and the front end portion of the input shaft 40, the front and rear end portions of the auxiliary shaft 42, and the output shaft 41 are rotatably supported. The rear end of the input shaft 40 is inserted into the front end of the output shaft 41 and is rotatably connected to each other.

Also in the case of this embodiment, the backward synchronizing device 63 is used.
3 is operated in the right direction in FIG. 3, the first and second idler gears 61 and 62 are connected, so that the driving force of the input shaft 40 is transmitted from the first speed gear 43 to the first idler gear 61, It is transmitted from the idler gear 62 to the sub shaft 42 via the third speed gear 54. And the final reduction gears 55, 4
8 is transmitted to the output shaft 41, and the output shaft 41 rotates in the direction opposite to that in the forward movement.

In the case of the second embodiment, a fifth-speed gear pair 45, 5 which is a gear pair of the highest speed stage is provided near the center of the case 70.
6 is arranged and the other low speed gears are arranged in the vicinity of both ends, so that when the input shaft 40 or the auxiliary shaft 42 bends, there is an effect that gear wear and noise can be reduced as a whole. .. Also, when idling, the output shaft 41 and the sub shaft 4
2 is stopped, and the fifth speed gear 45 and the third speed gear 46 arranged on the input shaft 40 are also stopped. Although the first speed gear 50 and the second speed gear 51 on the counter shaft 42 run idle, the rattling noise associated with engine rotational fluctuation is less than in the conventional case because the number of gears running idle is small. Also, the final reduction gear 4
8 and 55 are provided between the sub shaft 42 and the output shaft 41, and there is no reduction gear between the input shaft 40 and the sub shaft 42. Therefore, the synchronizers 47, 49, and 52 have the reduction gear gears. Not affected by the ratio. That is, the inertial weight acting on the synchronizers 47, 49, 52 is reduced by the gear ratio of the reduction gear as compared with the conventional one, and the synchronizing performance can be improved. Furthermore, since the driving torque of the input shaft 40 is transmitted to the first to fifth speed gear pairs without being amplified, the load on each gear pair becomes relatively smaller than in the conventional case, and the tooth width of each gear is reduced. Can be made smaller. This means that the axial dimension of the transmission can be reduced.

In the above two embodiments, the first idler gear and the first speed gear are meshed with each other, and the second idler gear and the third idler gear are engaged with each other.
However, the present invention is not limited to this. For example, the first idler gear and the second speed gear are engaged, and the second idler gear and the third speed gear, the fourth speed gear or the fourth speed gear or It may be meshed with any of the fifth speed gears, or meshed with the first idler gear and the first speed gear and meshed with the second idler gear and the second speed gear, the fourth speed gear or the fifth speed gear. May be combined. In addition,
In the above-described embodiment, the forward 5th speed, the reverse 1st speed for the FF vehicle and the F
Although the transmission for the R vehicle has been described, it goes without saying that the present invention is not limited to these embodiments. For example, the arrangement of various gears and the structure of the shift stages can be arbitrarily changed, and the wheel drive system can be applied to vehicles of other systems such as RR and midship type in addition to FF and FR.

[0025]

As is apparent from the above description, according to the present invention, since the reverse gear is obtained by utilizing the forward speed change gear, the reverse gears are provided for the first shaft and the second shaft. There is no need to provide it, and it is not necessary to extend the axial length. Further, since the first idler gear and the first gear are meshed with each other and the second idler gear and the fourth gear are always meshed with each other, no gear squeal or head hit occurs during the reverse shift. Since I tried to connect it,
A smooth reverse shift is possible. Further, since there are only two reverse gears, the first idler gear and the second idler gear, the number of gears is minimized, and the transmission can be reduced in size and weight.

[Brief description of drawings]

FIG. 1 is a schematic structural diagram of a first embodiment in which the present invention is applied to an FF vehicle transmission.

FIG. 2 is a side view showing a meshed state of each gear of the transmission shown in FIG.

FIG. 3 is a schematic structural diagram of a second embodiment in which the present invention is applied to an FR vehicle transmission.

[Explanation of symbols]

 2 Input shaft 3 Output shaft 6 1st speed gear (1st gear) 8 3rd speed gear (3rd gear) 11 3rd-4th speed switching synchronizer 14 1st speed gear (2nd gear) 16 1st- Second speed switching synchronizer 17 Third speed gear (fourth gear) 31 First idler gear 32 Second idler gear 33 Reverse synchronizer

Claims (1)

[Claims] 1. A first shaft on the input side, a second shaft on the output side parallel to the first shaft, a first gear fixedly mounted on the first shaft, and rotatable on the second shaft. A second gear that is supported and is in constant mesh with the first gear, and a third gear that is rotatably supported on the first shaft.
A gear, a fourth gear that is fixed to the second shaft, and that constantly meshes with the third gear, and a forward movement that selectively connects the second gear to the second shaft or the third gear to the first shaft. A gear shifter comprising a forward gear shift gear pair, and a first gear and a second gear, and a third gear and a fourth gear, each of which is parallel to the first shaft and the second shaft. A first idler gear that is always meshed with the first gear, a second idler gear that is coaxially and relatively rotatably arranged with respect to the first gear, and that is constantly meshed with the fourth gear; A reverse mechanism for a gear transmission, comprising: a reverse synchronizer that selectively connects idler gears.