JP2000018366A - Hydraulic and mechanical continuously variable transmission - Google Patents

Abstract

(57) [Problem] To provide a hydraulic / mechanical continuously variable transmission in which the front-rear length of a transmission case is made compact by devising an in-case arrangement structure of an HST and a planetary gear mechanism. SOLUTION: In a hydraulic / mechanical continuously variable transmission configured to perform a speed change of an output rotation by combining an HST 4 and a planetary gear mechanism 5, a planetary gear mechanism to which engine power is input via an input shaft 3. The pump 4p and the motor 4m constituting the hydrostatic continuously variable transmission 4 are arranged on both sides of the input shaft 3 on the side of the engine 5 in the state of being divided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic / mechanical continuously variable transmission combining a hydrostatic continuously variable transmission (hereinafter abbreviated as HST) and a planetary gear mechanism, that is, an HS.
The present invention relates to an improvement in HMT (abbreviation for hydro-mechanical transmission) that takes advantage of both the excellent shifting operability of T and the high transmission efficiency of a planetary gear mechanism.

[0002]

2. Description of the Related Art This type of HMT is disclosed in
As disclosed in Japanese Patent Application Laid-Open No. 120047, there is known a tractor used in a transmission. In other words, the rotational power is input to one of the three elements of the sun gear, the internal gear, and the planet carrier that constitute the planetary gear mechanism, and the output rotation is extracted from the other one of the three elements, and One of the two elements other than the remaining one is connected to the input or output to the HST and the output or input to the HST that does not correspond to the other one. It is configured to be linked with.

[0003]

In the above publication, the engine power is controlled by a pump (reference numeral 10) of the HST (reference numeral 9) and a sun gear (reference numeral 68) of the planetary gear mechanism (reference numeral 67). Therefore, the input shaft (reference numeral 6) becomes longer in the front and rear directions, and the front and rear length of the mission tends to be longer.

An object of the present invention is to provide a hydraulic / mechanical continuously variable transmission in which the front-rear length of the transmission case is reduced by devising the arrangement of the HST and the planetary gear mechanism in the case. .

[0005]

Means for Solving the Problems [Constitution] The present invention relates to a hydraulic / mechanical continuously variable transmission configured to perform a variable output rotation by combining a hydrostatic continuously variable transmission and a planetary gear mechanism. , A pump and a motor constituting a hydrostatic continuously variable transmission are arranged on both sides of the input shaft on the engine side of the planetary gear mechanism to which the engine power is input via the input shaft. It is characterized by the following.

[Operation] According to the configuration of the first aspect, the HST
The front-rear length required for HST, that is, the front-rear length as a transmission, is shortened compared to the conventional case where a pump and a motor are arranged in series by parallel arrangement by distributing the pump and motor to both sides of the input shaft. can do. Further, since the input shaft is disposed between the pump and the motor, the HST and the planetary gear mechanism are not relatively displaced in the left-right or vertical direction.

[Effect] As a result, it is possible to provide a hydraulic / mechanical continuously variable transmission in which the entire length of the transmission case is reduced while the outer shape of the case does not partially project to the side.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a transmission for a tractor, which is a transmission M having a transmission case 1 having a monobody structure having a front end directly connected to a rear end of an engine E and also serving as an airframe. It is configured.

The mission M includes a flywheel 2 with a pulsation absorbing mechanism for transmitting an engine output shaft to an input shaft 3, and an HST.
4, a planetary gear mechanism 5, a traveling auxiliary transmission mechanism 6, a rear wheel differential mechanism 7, a PTO intermediate shaft 8, a PTO clutch 9, a front wheel drive DT interlocking mechanism 10, a front wheel drive shaft 11, etc. 1 and is configured.

As shown in FIGS. 4 and 5, a variable pump 4p and a variable motor 4m constituting the HST 4 are connected to a pump shaft 1
The input shaft 3 and the motor shaft 13 are arranged side by side on the left and right under the input shaft 3 arranged at the front end of the transmission case 1 so as to be located laterally to each other. The front end of the transmission case 1 has an upper surface of the case located higher than that after that, and a flange portion 15 for bolt connection to the engine E is formed at the front end.

As shown in FIGS. 2 and 4, from the vertical wall 1a at the front of the transmission case 1 to the front, the outer case 1A and the inner case 1B are integrated via the vertical wall 1a. It has a heavy cylinder case structure, and the inner case portion 1B and the oil passage block 16 serving as a front cover thereof have an HST4
As a casing. Oilway block 16
Has an oil passage connecting the pump 4p and the motor 4m,
A charge pump 17 and the like are formed. Reference numeral 18 denotes a pump actuator for variably operating the variable pump 4p, and reference numeral 19 denotes a motor actuator for variably operating the variable motor 4m.

The interior of the inner case 1B and the rear part from the vertical wall 1a are moist chambers containing lubricating oil, whereas the outer case 1A other than the inner case 1B is equipped with a flywheel 2. It is formed in a dry room without oil. Incidentally, the dry chamber portion corresponds to a clutch housing portion in a conventional transmission case having a monobody structure. Reference numeral 14 denotes a shift gear for shifting the sub-transmission mechanism 6.

Next, the flow of power will be described.
Is input to the planet carrier 20 of the planetary gear mechanism 5, and the internal gear 22 circumscribing the plurality of planet gears 21 supported by the carrier 20 drives the pump shaft 12 via the intermediate rotating body 23. Sun gear 24 inscribed in planetary gear 21
The output rotation of the motor shaft 13 is transmitted to the sun shaft 25 on which is formed through the intermediate rotating body 26, and the rotational power of the sun shaft 25 is output to the auxiliary transmission mechanism 6.

Therefore, the variable pump 4p and the variable motor 4m
By performing the variable operation described above, the input rotation entering the planetary carrier 20 can be steplessly changed in the forward and reverse directions and taken out of the sun shaft 25, and a neutral state in which power is not transmitted can also appear. The rotational power of the input shaft 3 is transmitted to the rear PTO shaft 27 via the PTO intermediate shaft 8 and the PTO clutch 9 in a state where no speed change is performed.

That is, the HMT is composed of the sun gear 24, the internal gear 22, and the planetary carrier 20 constituting the planetary gear mechanism 5.
Of the three elements, the rotational power is input to the planetary carrier 20, the output rotation is extracted from the sun gear 24, the internal gear 22 is linked to the input to the variable pump 4p of the HST 4, and the output of the HST 4 to the variable motor 4m is It is configured to be linked with the sun gear 24.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic structure of a transmission system.

FIG. 2 is a cross-sectional side view showing the structure of the front part of the mission.

FIG. 3 is a cross-sectional plan view showing a structure of a front portion of the mission.

FIG. 4 is a front view showing an arrangement structure of the HST.

FIG. 5 is a cross-sectional view of a mission showing an arrangement of each shaft.

[Explanation of symbols]

 Reference Signs List 3 input shaft 4 hydrostatic stepless transmission 4p pump 4m motor 5 planetary gear mechanism

Claims (1)

[Claims] 1. A hydraulic / mechanical continuously variable transmission configured to perform a speed change of an output rotation by combining a hydrostatic continuously variable transmission and a planetary gear mechanism, wherein an engine power is transmitted via an input shaft. A hydraulic / mechanical continuously variable transmission in which a pump and a motor constituting the hydrostatic continuously variable transmission are arranged on both sides of the input shaft on the engine side of the planetary gear mechanism to which is input. Transmission.