JPH03117750A - Speed change gear - Google Patents

Abstract

PURPOSE:To obtain a large reduction gear ratio, while keeping the dimension of a speed change gear in the radial direction as small as possible, by providing a sub-speed changing mechanism with a countershaft, an epicyclic gear mechanism, which is supported to the countershaft in a rotatable manner, first and second sub-gear trains, both of which are coupled to input and output shafts, respectively, in a rotatable manner, and an engaging/disengaging means. CONSTITUTION:When an extra low speed stage is selected, namely when a reduction gear 5, which forms a first sub-gear train Ga, is engaged with a sun gear 9 of an epicyclic gear mechanism 16 lying on a counter shaft 8 by a synchro-mesh 10 (engaging/ disengaging means) in such a manner that both gears 5 and 9 rotate as an integrated body, the gear 9 rotates in the same direction as that of the gear 5, while three pinion gears 13, which are engaged with the gear 9 along its periphery, rotate in the reverse direction because of a rotation, which is given to the gear 5 by an input shaft 2 via a driving gear 1. Since the center position of a gear 13 is fixed by both a crank case 11 and a pinion shaft 12, a ring gear 14 is driven in the reverse direction to that of the gear 9. An extra slow speed driven gear 15 is driven by the gear 14 via an external both gear 14b, which forms a second sub-gear train Gb, so that a rotation in the same direction as that of a going-forward stage of a main speed change stage is given to an output shaft 3.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a transmission, and more particularly, to a transmission.

A main transmission mechanism that has a gear train of multiple gears that can be selectively engaged between the output shaft and an auxiliary transmission mechanism that has an extremely low speed gear train that allows the speed to be lower than the lowest gear of the main transmission mechanism. The present invention relates to a transmission device comprising: and.

[Prior Art] Vehicle transmissions generally have 4 to 5 forward gears and -2 reverse gears, but for example, in full width drive vehicles, especially off-road vehicles, there are For this purpose, there is a demand for providing an extremely low speed gear that is lower than the lowest forward gear (-th gear).

In order to obtain such an extremely low gear, a sub-transmission mechanism has conventionally been installed in the transmission case in addition to the main transmission mechanism. Japanese Patent Publication No. 63-39450 discloses a vehicle power unit equipped with such an auxiliary transmission mechanism.

As the sub-transmission mechanism, a gear train is described that rotates on two shafts, an intermediate shaft and a sub-shaft, which are arranged parallel to the input/output shaft.

[Problem 8 to be solved by the invention] Since the sub-transmission mechanism of the power unit of the above-mentioned publication employs two shafts, an intermediate shaft and a sub-shaft, the dimension in the direction perpendicular to the shaft (radial direction) tends to be large. It is. Due to space and weight constraints in vehicles, it is desirable to add fewer shafts in order to make the transmission smaller and lighter. On the other hand, in order to reduce the number of additional shafts and reduce the radial dimension, it is necessary to reduce the distance between each shaft, but reducing the distance between the shafts places restrictions on the diameter of the gear, and A problem arises in that it is not possible to obtain such a large reduction ratio.

Therefore, the present invention provides a transmission including a main transmission mechanism and a sub-transmission mechanism, which has a large reduction ratio necessary for an extremely low gear while keeping the radial dimension as small as possible. The primary purpose is to

Furthermore, in providing an auxiliary transmission mechanism for extremely low speeds, the present invention reduces the number of additional parts as much as possible to suppress an increase in the weight of the transmission, and also aims for compatibility of parts with other transmissions that do not have an auxiliary transmission mechanism. This is the second purpose.

[Means for Solving the Problems] The first object of the present invention is to provide a main transmission mechanism comprising a gear train with a plurality of gears that can be selectively engaged between two human power shafts and an output 1. A transmission device comprising: a sub-transmission mechanism having an extremely low-speed gear train for achieving a speed lower than the lowest gear position of the main transmission mechanism.

The sub-transmission mechanism includes a sub-shaft, a planetary gear mechanism rotatably supported on the sub-shaft, and first and second sub-gear trains rotationally coupled to an input shaft and an output shaft, respectively.

engaging and disengaging means, one of the first auxiliary gear train and the second auxiliary gear train is rotatably coupled to the planetary gear mechanism, and the other engages and disengages when the very low speed gear train is selected. It is rotatably coupled to the planetary gear mechanism via a detachment means. This is achieved by a transmission device characterized by the following.

Further, the drive gear and wave gear of the first auxiliary gear train are gears rotatably supported on the lowest gear drive gear of the main transmission mechanism and the sun gear of the planetary gear mechanism, respectively, and The detaching means connects the wave gear and the sun gear in a detachable manner, or the second auxiliary gear train includes an external gear formed in a ring gear of the planetary gear mechanism, and Both can be employed, and in either case the second objective of the present invention is better achieved.

[Function] When the very low speed gear stage is selected, the rotation from the human power shaft constitutes a sub-transmission mechanism by the operation of the engagement and disengagement means. It is transmitted to the output shaft via the first auxiliary gear train, the planetary gear mechanism, and the second auxiliary gear train. Since the only shaft added for the auxiliary transmission mechanism is the auxiliary shaft, the radial dimension can be kept small, and the planetary gear mechanism can provide a large reduction ratio, which is necessary for an extremely low speed gear.

The first auxiliary gear train serves as a driving gear and wave gear.

To reduce the number of additional parts by employing a gear that is pivotally supported on the drive gear of the lowest gear of the main transmission mechanism and the sun gear of the planetary gear mechanism, respectively, and providing an engagement/disengagement means between the wave gear and the sun gear. At the same time, it is possible to suppress the increase in dimension in the axial direction.

By including the external gear formed in the ring gear of the planetary gear mechanism in the second auxiliary gear train, additional gears can be substantially saved.

[Example] Next, an example of a transmission according to the present invention will be described with reference to the drawings. FIG. 2 is a schematic diagram of the arrangement of each shaft and the meshing relationship of gears of the transmission of this embodiment, viewed from the axial direction. In FIG. 2, 2 and 3 degrees 8 represent the input shaft, output shaft and sub-shaft, respectively.

A drive gear 1 that rotates together with an input shaft 2 and this drive gear 1
The input side gear train (first sub-gear train) Ga of the extremely low-speed gear mechanism is composed of the reduction gear 5 which is driven by the auxiliary shaft 8 and rotates on the countershaft 8, and the external gear of the ring gear 14 which rotates on the countershaft 8. 1
4b and the very low speed wave gear 15 rotating on the output shaft 3 constitute an output side gear train (second auxiliary gear train) Gb. Teeth i'li4 is a wave gear of the first pulley train of the main transmission mechanism,
It meshes with the drive gear 1 of the -th pulley train.

FIG. 1 is a longitudinal sectional view of the transmission of this embodiment, and the second
It represents the 1-1 cross section of the figure. In addition.

FIG. 2 is also a view from the ■-■ arrow in FIG. 1.

The input shaft 2 coupled to a clutch (not shown) is rotatably supported by an end 6a of the clutch housing 6 and a support part 7a of the transmission case 7 via bearings 21 and 22, respectively, and an output parallel to the input shaft 2 Similarly, the shaft 3 also has a bearing 23.
It is rotatably supported via 24. Between the input shaft 2 and the output shaft 3, there is a gear train that constitutes a main transmission mechanism and that can be selectively engaged.
, second gear train G2. Third gear train G3. Fourth gear train G4. Fifth gear train G5. They are arranged as a reverse gear train Gr.

One of the gears in each gear train is fixed to the respective shaft, and the other gear is rotatably supported on the respective shaft. For example, the driving gear 1 of the first pulley train G1 is integrally formed with the human power shaft 2, and the wave gear 4 is rotatably fitted and supported on the output shaft 3.

Synchronizers 25, 26, and 27 are disposed corresponding to each gear train that constitutes the main transmission mechanism, and the operation of the synchronizer causes the gears rotatably supported on each shaft to rotate together with the shaft. The gear train transmits rotation from the input shaft to the output shaft.

A countershaft 8 for the subtransmission mechanism is connected to the clutch housing end 6
a and the mission case wall 7b. The drive gear 1 of the -th pulley train G1 also serves as the drive gear of the first auxiliary gear train Ga, and meshes with the reduction gear 5 driven by this. The reduction gear 5 is rotatably supported on a sun gear 9 of a planetary gear mechanism 16, which is rotatably supported on a subshaft 8. On the sun gear 9, an engagement means (synchronization device) is provided that connects the sun gear 9 and the reduction gear 5 in a detachable manner.
10 are provided.

Three pinion gears 13 constituting the planetary gear mechanism are rotatably supported by a pinion shaft 12 fixedly supported by the carrier case 11 and mesh with the sun gear 9. The carrier case 11 is rotatably supported by the subshaft 8 by spline fitting. The three pinion gears 13 are simultaneously meshed with the internal gear of the ring gear 14, and the sun gear 9° carrier case 11. Binion shaft 12. The pinion gear 13 and the internal gears of the ring gear 14 constitute a planetary gear mechanism 16 as a whole. An external gear 14b formed on the outer periphery of the ring gear 14 is connected to the output shaft 3.
The external gear 1-4b of the ring gear and the extremely low speed wave gear 15 constitute a second auxiliary gear train Gb.

The operation of the transmission device configured in this way will be explained with reference to FIG. 1 as well.

When the very low gear is not selected, i.e. when the synchronizer l
When O is not operating, the rotation applied to the input shaft 2 passes through the drive gear 1 of the -th pulley train G1 and rotates the reduction gear 5 that meshes with it, but this rotational force is applied to the sun gear 9. is not transmitted.

On the other hand, the rotation of the output shaft 3 given from the input shaft 2 via one of the gear trains of the main transmission mechanism selected from the two is transmitted from the very low speed driven gear 15 constituting the second auxiliary gear train Gb to the ring gear. 14 external m gear 14b, and via pinion gear 13 to sun gear 9. Therefore, none of the gears constituting the auxiliary transmission mechanism idles and generates noise even when the extremely low speed gear is selected.

When a very low gear is selected, that is, when the synchronizer IO couples the reduction gear 5 and the sun gear 9 into a rotating body, the rotation applied to the reduction gear 5 from the input shaft 2 via the drive gear 1 causes , sun gear 9 rotates in the same direction, and three pinion gears 13 disposed on the outer periphery of sun gear 9 and meshing therewith rotate in opposite directions. Since the center position of the pinion gear 13 is fixed by the crankcase 11 and the pinion shaft 12, the ring gear 14 is connected to the sun gear 9.
and drive in the opposite direction. The ring gear 14 drives an extremely low speed driven vehicle 15 via its external gear 14b, and therefore provides an extremely low speed rotation to the output shaft 3 in the same direction as the forward gear of the main gear.

In this embodiment, an example in which the subshaft 8 is fixedly supported by the clutch housing 6 and the transmission case 7 has been shown.1.
However, the present invention is not limited to this, and the subshaft 8 may be rotatably supported relative to a clutch housing or the like, and rotated together with the sun gear 9, and the carrier case 11 may be fixed to the clutch housing 6, thereby achieving the same structure as in the above embodiment. It is also possible to obtain a similar very low gear.

Furthermore, an example has been shown in which the synchronizer 10 serving as the engagement/disengagement means is provided between the first sub-gear train and the planetary gear mechanism, and the second sub-gear train and the planetary gear mechanism are connected in a constantly rotating unit. However, the invention is not limited to this, and conversely, the second auxiliary gear train and the planetary gear mechanism may be coupled via a locking/disengaging means, and the first auxiliary gear train and the planetary gear mechanism may be coupled into a constantly rotating unit. It is possible.

[Effects of the Invention] In the present invention, the sub-transmission mechanism includes a sub-shaft, a planetary gear mechanism rotatably supported on the sub-shaft, and first and second planetary gear mechanisms rotatably coupled to the input shaft and the output shaft, respectively. comprising two auxiliary gear trains and an engaging/disengaging means, one of the first auxiliary gear train and the second auxiliary gear train being rotationally coupled to the planetary gear mechanism;
The other gear is rotationally coupled to the planetary gear mechanism via the engagement and disengagement means when the very low speed gear train is selected. Due to the configuration of the transmission device, the planetary gear mechanism can have a large reduction ratio, so it can only have one shaft added, and is compact in the radial direction and is necessary for extremely low speed gears. It was possible to provide a transmission with an auxiliary transmission mechanism having a large reduction ratio.

As the drive gear and gear wheel of the first auxiliary gear train, the drive gear and planet l! of the lowest gear of the main transmission mechanism are respectively used. Adopts a gear rotatably supported on the sun gear of the 1rli mechanism,
An engaging/disengaging means releasably couples the drive gear and sun gear. With this configuration, there is no need to add another gear to the human power shaft as an auxiliary transmission mechanism, and there is no need for an extension in the axial direction, making it possible to use a transmission with an auxiliary transmission mechanism whose parts are compatible with other models. I was able to provide it.

By employing an external gear formed in a ring gear constituting a planetary gear mechanism as the output side gear train, it was possible to provide a more compact transmission with an auxiliary transmission mechanism.

[Brief explanation of drawings]

FIG. 1 is a developed vertical cross-sectional view of a transmission according to an embodiment of the present invention, and is a view taken along arrow I-1 in FIG. FIG. 2 is an axial arrow view showing the arrangement of each shaft of the transmission of the embodiment shown in FIG. 1, and is a view taken along the line ■-■ in FIG. FIG. 3 is a longitudinal cross-sectional development view of a conventional transmission. It is. (Explanation of symbols) 1; First series of float train drive gear 2; Input shaft 3; Output shaft 4; First series of float gear wave gears 5; Reduction gear 6; Clutch housing 7; Mission case 8; Subshaft 9; Sun gear IO; synchronizer (engagement/disengagement means) 11, carrier case 12, pinion shaft 13; pinion gear 14. Ring gear 15, extremely low speed driven gear 16; planetary gear mechanism 25-27: synchronizer 01-G
5; First to first auxiliary gear train Ga; Input side auxiliary gear train (first auxiliary gear train) Gb; Output side auxiliary gear train (second auxiliary gear train) Gr; Reverse gear train

Claims (3)

[Claims] (1) A main transmission mechanism that includes a gear train with multiple gears that can be selectively engaged between an input shaft and an output shaft, and an extremely low speed that is lower than the lowest gear of the main transmission mechanism. A transmission including a sub-transmission mechanism having a gear train, wherein the sub-transmission mechanism includes a sub-shaft, a planetary gear mechanism rotatably supported on the sub-shaft, and a planetary gear mechanism rotatable on an input shaft and an output shaft, respectively. comprising first and second auxiliary gear trains coupled to each other, and an engaging/disengaging means,
One of the first auxiliary gear train and the second auxiliary gear train is rotationally coupled to the planetary gear mechanism, and the other is connected to the planetary gear via the engagement and disengagement means when the very low speed gear train is selected. A transmission characterized in that it is rotationally coupled to a mechanism. (2) The drive gear and wave gear of the first auxiliary gear train are gears rotatably supported on the lowest gear drive gear of the main transmission mechanism and the sun gear of the planetary gear mechanism, respectively; 2. The transmission according to claim 1, wherein an engaging/disengaging means releasably couples the wave gear and the sun gear. (3) The transmission according to claim 1 or 2, wherein the second auxiliary gear train includes an external gear formed in a ring gear of the planetary gear mechanism.