JPS62113960A - Hydro-mechanical transmission gear - Google Patents

Abstract

PURPOSE:To raise the efficiency of engine power over the whole range of car speed, by directly connecting the engine power to a hydro-mechanical transmission (HMT), not through a clutch, and setting an auxiliary sped change gear at its output side. CONSTITUTION:A flywheel 2, HMT 3, a forward/backward change gear 4, and an auxiliary speed change gear 5 are housed in a transmission case 1. A motor gear 14 for the hydraulic pump.motor 12 of HMT 3, is connected to a planet gear unit 16. Engine power is output to a cylindrical shaft 22 which is an output shaft, after being continuously changed by the hydro-mechanical transmission gear 3. This shaft 22 is equipped with the hydraulic clutch 30 of the forward/backward change gear 4, and the power is further transmitted to wheels, through being subjected to 1-2 or 2-4 steps speed change, by the auxiliary speed change gear 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hydraulic-mechanical transmission used in a vehicle such as a tractor.

(Prior art) Hydraulic-mechanical transmission (Hydro-mechanical transmission) as a continuously variable transmission
-Mechanical Transmission
(hereinafter abbreviated as HMT) is, for example, ``Automotive Technology J
Vol, 30, Fish 9, 1976, Page 765~
It is well known as described in No. 770.

In other words, HMT is a hydrostatic variable speed FIA (FIA) system that uses a hydraulic pump and a hydraulic motor.
Transmission (hereinafter abbreviated as H3T)
Rather than converting all of the transmitted power into hydraulic power as in the method described above, a part of the transmitted power is converted into hydraulic power and the remainder is transmitted as highly efficient mechanical power. In other words, HMT divides the power into two paths, transmits the minimum amount of power necessary to cause a continuously variable speed action to the hydraulic system, and
Others are mechanically transmitted and have a differential mechanism that smoothly merges the power of both.

There are two types of HMTs: an output split type that connects the hydraulic pump to the input shaft system, and an input split type that connects the hydraulic motor to the output shaft system.This type of HMT can be used for the mission of vehicles such as agricultural tractors. Various studies are being conducted to adopt this technology.

(Problems to be Solved by the Invention) As shown in FIGS. 5 and 6, the efficiency of the HMT increases near the reference speed ratio, and decreases in the low speed range or high speed range on the backward and forward sides. There is.

Therefore, in a transmission using only this HMT,
As shown in FIG. 7, there is a problem in that high efficiency cannot be maintained over the entire range of vehicle speeds. (These problems are explained in detail in the above-mentioned publication, so the details are omitted.) Therefore, the present invention provides efficient continuously variable transmission over the entire vehicle speed range from 0 to the maximum speed. The purpose is to provide a hydraulic-mechanical transmission.

(Means for Solving the Problems) The present invention is characterized in that engine power is directly connected to a hydraulic-mechanical transmission without using a clutch, and a forward/reverse switching device and an auxiliary drive are provided on the output side of the transmission. The reason lies in the fact that it is equipped with a transmission.

(Function) According to the present invention, engine power is outputted to the output shaft through a hydraulic-mechanical transmission (HMT) in a continuously variable manner. Since this output shaft is provided with a forward/reverse switching device, the power is transmitted rearward as forward or reverse power. Furthermore, this power is transmitted to 1-2 or 2-2 through an auxiliary transmission.
The power is transmitted to the wheels through four gears.

That is, according to the present invention, the HMT uses a small hydraulic power ratio that is efficient, and allows continuously variable speed at each gear stage of the sub-shift.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

What is shown in Figure 1 is a hydraulic system using an output split type HMT.
It is a mechanical transmission, and FIG. 2 is a schematic diagram thereof.

In the figure, 1 is a mission case, and the mission case 1 has a flywheel 2, an HMT 3, a forward/reverse switching device 4, and an auxiliary transmission 5 built therein.

The flywheel 2 is fixed to the end of the crankshaft 6 of the engine. A spline boss 7 is fixed to the center of the flywheel 2, and a main shaft 8 is attached to the spline boss 7.
are connected by splines.

The outer peripheral surface of the spline boss 7 is supported by a partition wall 10 via an oil seal 9, and the tip of the main shaft 8 and the inner surface of the spline boss 7 are sealed via an oil seal 11. Therefore, the flywheel 2 is completely isolated from the other chambers of the transmission case 1 by the partition wall 10 and the oil seals 9 and 11. By sealing the flywheel chamber in this way, oil does not enter the flywheel chamber, so there is no oil agitation resistance caused by the flywheel 2, air bubbles are less likely to enter the oil, and the oil is coupled to the flywheel 2. Seals on the starter motor are no longer required.

12 is a hydraulic pump/motor of the HMT, 13 is a pump gear, and 14 is a motor gear. The pump gear 13 meshes with a gear 15 splined to the main shaft 8. Motor gear 14 is coupled to planetary gearing 16 .

This planetary gear device 16 includes a sun gear 17 spline-coupled to the main shaft 8, and a planetary gear 18 meshing with the sun gear 17.
, a carrier 19 that supports the planetary gear 18, and a ring gear 20 that internally encloses the planetary gear 18. An external gear 21 is formed on the ring gear 20, and the motor gear 14 meshes with the external gear 21.

The carrier 19 is spline-coupled to a cylindrical shaft 22 that is fitted around the main shaft 8 so as to be relatively rotatable. In other words, this cylinder shaft 2
2 is the output shaft of HMT3. The ring gear 20 is rotatably supported by a boss of the partition wall 23 via a bearing.

A forward gear 24 and a reverse gear 2 are connected to the cylindrical shaft 22 which is the output shaft.
5 are spline-coupled.

26 is a sub-shaft arranged parallel to the main axis 8;
A forward gear 27 and a reverse gear 28 are fitted onto the gear 6 so as to be relatively rotatable. The forward gear 27 is always in mesh with the forward gear 24 on the cylinder shaft 22, and the reverse gear 28 is connected to the reverse gear 24 on the cylinder shaft 22 through a count gear 29 (see FIG. 2).
5 is always engaged.

Reference numeral 30 denotes a hydraulic clutch for forward/reverse switching, and when the clutch 30 is turned on or off, one of the forward and reverse gears 27 and 28 is integrally connected to the subshaft 26. In this way, the aforementioned hydraulic clutch 30, gears 27, 28, etc. constitute the aforementioned forward/reverse switching device 4.

The sub-transmission device 5 has a high-speed gear 31 spline-coupled on the sub-shaft 26 behind the reverse gear 28, and
1 meshes with 32 of double gears 32 and 33 which are fitted onto the cylindrical shaft 22 so as to be relatively rotatable. Double gear 32.3
No. 3 33 meshes with a gear 34 which is fitted around the subshaft 26 so as to be relatively rotatable. These ends of the countershaft 26 and the gear 3
The end of the second sub-shaft 35 faces the end of the second sub-shaft 35, and a shifter 36 is provided at the joint thereof to be movable in the axial direction. This movement of the shifter 36 connects the gear 34 and the second subshaft 35, or connects the subshaft 26 and the second subshaft 35, thereby switching between high speed and low speed.

In this embodiment, the sub-transmission device 5 is disclosed as having a two-speed transmission, but it may have a different number of speeds.

The one shown in Fig. 3 uses an input split type HMT, and the difference from Fig. 2 is that the gear 15 is spline-coupled to the cylindrical shaft 22, and the rest is the same as Fig. 2. It is.

Note that the present invention is not limited to the above embodiments,
The planetary gear device 16 may be coupled to the main shaft 8, motor gear 14, etc. in other combinations.

(Effects of the Invention) According to the present invention, by using the range S in which the reference speed ratio is small as shown in FIG. 5.6, highly efficient power transmission as shown in FIG. 4 can be obtained.

Although FIG. 4 illustrates a case where the sub-shift has four stages, the same applies to the two-stage sub-shift shown in FIG.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is a schematic diagram thereof, and shows an HMT output division method, FIG. 3 shows an input division method, and FIG. 4 is a graph of vehicle speed and efficiency, Fig. 5 is a graph showing the efficiency of HMT with output splitting, Fig. 6 is a graph showing the efficiency of HMT with input splitting, and Fig. 7 is a graph showing the efficiency when only HMT is used. It is. 3...HMT, 4...Forward/reverse switching device, 5...
Sub-transmission.

Claims (1)

[Claims] (1) A hydraulic-mechanical transmission system that directly connects engine power to a hydraulic-mechanical transmission without using a clutch, and is equipped with a forward/reverse switching device and an auxiliary transmission on the output side of the transmission. .