JPH058185Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a vehicle transmission that combines a planetary gear device and a hydrostatic transmission.

(Conventional technology) As a transmission for vehicles such as tractors, "Automotive Technology" VO130 No.9 1976 P756
Some are hydro-mechanical, as disclosed in No. 770. This system is equipped with a planetary gear system and a hydrostatic transmission, which divides the power from the engine into two paths, and the hydraulic system uses the hydrostatic transmission to provide the minimum amount of power necessary to produce continuously variable speed. It is a system that transmits other power mechanically through a planetary gear device, so that the power of both is smoothly divided. This also combines high efficiency of the device.

This type of hydraulic-mechanical transmission has an output split type that is driven by the input part of the three elements that make up the planetary gear system, depending on the drive type of the hydraulic pump of the hydrostatic transmission. , and an input split type that is driven by the output section.

In the output split type, for example, if the rotational speed of the input shaft, that is, the rotational speed of the sun gear and the rotational speed of the hydraulic pump are constant, and the stroke volume of the hydraulic pump is changed from the reverse rotation side to the forward rotation side, the rotation of the ring gear can be changed. Along with this, there is a continuous change from reverse rotation to forward rotation, so
The rotational speed of the carrier changes steplessly from the reverse side, through a stop, and then to the forward side. Therefore, the input is divided by the drive gear of the hydraulic pump, flows through both the sun gear and the hydrostatic transmission, and is combined at the carrier to produce the output.

The input split type differs from this in that the hydraulic pump is coupled to the output shaft system.

(Problem to be solved by the invention) Hydraulic-mechanical transmissions are designed to reduce the size and weight of hydrostatic transmissions by minimizing the hydraulic power ratio, which is the ratio of hydraulically transmitted power to the total transmitted power. It is possible to improve the overall transmission efficiency.

However, in the output split type, the hydraulic power ratio on the forward side reverses positive and negative from the speed ratio where the rotation ratio of the hydraulic motor becomes 0, that is, the reference speed ratio, and becomes negative in the lower speed range than the reference speed ratio. Although the hydraulic power ratio is always positive on the reverse side (negative speed ratio), it also rises rapidly in the low speed range. Therefore, although the hydraulic power ratio is smaller than 1 in the forward mid-speed range and the efficiency is improved, the hydraulic power ratio becomes extremely large in the low forward speed range, resulting in a significant drop in efficiency.

On the other hand, in the input split type, unlike the output split type, the hydraulic power ratio changes linearly over both forward and backward travel ranges, but it increases in the forward high speed range, so in this speed range, the hydraulic power ratio There are drawbacks.

Therefore, conventional hydraulic-mechanical transmissions only employ either output splitting or input splitting, so in the case of vehicles such as tractors that require shifting over the entire range from low to high speeds,
There is a drawback that high transmission efficiency cannot be obtained in all speed ranges. For this reason, the application is limited to work in a speed range where transmission efficiency is good, and versatile use is not possible.

In view of these conventional problems, the present invention allows the output division method and input division method to be selected as necessary.
The purpose is to always be able to use it with high transmission efficiency.

(Means for Solving the Problems) The present invention consists of a planetary gear device 8 that transmits power from an input shaft 3 to an output shaft 5, a hydraulic pump 16, and a hydraulic motor 17, and the planetary gear device 8 is configured. In a vehicle transmission equipped with a hydrostatic transmission 15 that controls the rotation of one of the three elements, a hydraulic pump 16 of the hydrostatic transmission 15 is connected to the input shaft 3 and the output shaft 5. A switching means 21 is provided for selectively switching and connecting.

(Function) When the switching means 21 is switched and connected to the input shaft 3 side,
The hydraulic pump 16 is driven by the input shaft 3, which is an output split type. Therefore, if used in the forward high speed range, the hydraulic power ratio will be small and the transmission efficiency will be high.

When the switching means 21 is connected to the output shaft 3 side, an input split type is adopted in which the hydraulic pump 16 is driven by the output shaft 3. Therefore, if used in the low forward speed range, the hydraulic power ratio will be small and the transmission efficiency will be improved.

Therefore, by appropriately switching the switching means 21 to select the output split type in the forward high speed range and the input split type in the forward low speed range, high transmission efficiency can always be obtained and the system can be used for work at any speed. Can be used.

(Example) The present invention will be described in detail below with reference to the illustrated embodiment. In FIG. 1, 1 is a crankshaft of an engine, and has a flywheel 2. As shown in FIG.

Reference numeral 3 denotes an input shaft, which is interlocked with the flywheel 2, extends rearward, and is supported by a bearing 4.

Reference numeral 5 denotes an output shaft having a cylindrical structure, which is fitted around the input shaft 3 and supported by bearings 6 and 7.

8 is a planetary gear device, which has a sun gear 9 attached to the input shaft 3, a planet gear 10 meshed with the sun gear 9, an arm 11 attached to the output shaft 5, and the planet gear 10. The ring gear 14A to be engaged is formed and the bearing box 12
A carrier 14 is fitted and supported via a bearing 13 on the
It is composed of:

15 is a hydrostatic transmission that rotationally controls the carrier 14 of the planetary gear device 8;
and a hydraulic motor 17 are integrally coupled via a center section 18. The hydraulic pump 16 is a swash plate variable displacement pump, and the hydraulic motor 17 is a swash plate constant displacement motor, and both are fluidly coupled.

19 is a hydraulic pump gear; hydraulic pump 1
6, and this hydraulic pump gear 19 is selectively connected to the input shaft 3 and the output shaft 5 via a hydraulic clutch type switching means 21.

The switching means 21 is connected to the input shaft 3 as shown in FIG.
A clutch body 22 rotatably supported across the output shaft 5 is provided with a pair of hydraulic clutches 23 and 24 for output splitting and input splitting. A gear 25 is provided.
Each hydraulic clutch 23, 24 has a piston 30, a clutch plate 28, 29 interposed between a boss body 26, 27 on the shaft 3, 5 and a clutch body 22,
When the pressure is tightened at 31, it becomes connected, and the shaft 3 or 5
The hydraulic pump 16 can be driven by the power from.

Therefore, when the hydraulic clutch 23 of the switching means 21 is connected, the hydraulic pump 16 is driven by the power from the input shaft 3, resulting in an output split type, and when the hydraulic clutch 24 is connected, the planetary gear device 8 is driven. It is an input split type in which the hydraulic pump 16 is driven by the power from the output shaft 5, which has passed through the output shaft 5, and can be used selectively.

32 is a hydraulic motor gear, and carrier 14
The shaft 34 is connected to a bearing box 35 as a unit via a bearing, and is connected to a motor shaft 36 via a coupling.
is attached with bolts.

39 is one support, 40 is the other support, and the hydrostatic transmission 15 is supported by the housing 37 by the pair of supports 39 and 40. 41 is a cover attached to the housing 37.

Reference numeral 42 denotes a sub-width shift, which has a forward hydraulic clutch transmission section 43 and a reverse hydraulic clutch transmission section 44, and is interlocked with the output shaft 5 via gear mechanisms 45 and 46, respectively.

46A is an interlocking shaft, which is interlocked with the speed change subshaft 42 via a clutch 47A, and this interlocking shaft 4
A differential mechanism (not shown), etc. is provided via 6A. 47 is a speed change gear mechanism.

In the above configuration, when the hydraulic clutch of the switching means 21 is connected, the power from the input shaft 3 is transferred to the gear 2.
5 to the hydraulic pump gear 19, and the hydraulic pump 16 is driven by the input shaft 3, resulting in an output split type.

Further, when the hydraulic clutch 23 is disengaged and the hydraulic clutch 24 is connected, the power on the output shaft 5 side via the planetary gear device 8 is transmitted to the hydraulic pump gear 19 via the gear 25, and the hydraulic pump 16 is
Since it is driven by , it is an input split formula.

Therefore, the output division type and the input division type can be arbitrarily selected by operating a valve (not shown).

Therefore, for example, the hydraulic clutch 23 is connected when traveling at high speed on the forward side. Then, a part of the power from the engine is transmitted to the hydrostatic transmission 15 via the input shaft 3, the hydraulic clutch 23, and the gears 25, 19. Controls the rotation of ring gear 14A of device 8. This allows the planetary gear device 8 to perform stepless deceleration, and the power of the engine to be transmitted to the output shaft 5 with high efficiency by changing the speed steplessly.

That is, if the swash plate angle of the hydraulic pump 16 is arbitrarily changed during gear shifting, even if the rotation speed of the hydraulic pump side is constant, the rotation speed of the motor shaft 36 of the hydraulic motor 17 changes steplessly, and the gear 32 , 33, the rotation of the ring gear 14 can be controlled. Therefore, for example, the hydraulic motor 17 drives the ring gear 1.
If the rotation of 4A is stopped, the power from input shaft 1 is
The speed is reduced by the gear ratio of the sun gear 9 and the planetary gear 10, and is transmitted to the output shaft 5 via the carrier 14A. Further, when the ring gear 14A is rotated by the hydraulic motor 17 in the same direction as the rotation direction of the output shaft 5, the rotation speed of the output shaft 5 increases in accordance with the rotation speed, and high-speed running can be achieved with high efficiency.

In addition, in the above embodiment, the hydraulic pump gear 19
The hydraulic pump 16 is driven at a constant gear ratio during both output division and input division, but as shown in FIGS. 3 and 4,
The gear ratio may be made different between the output division and the input division. That is, in this case, the hydraulic clutches 23, 24 are provided separately from each other by dividing the two clutch bodies 48, 49, and the drive gears 50, 51 are provided respectively, and the hydraulic clutches meshing with the hydraulic clutches 23, 24 are provided separately. Pump gears 52 and 53 are provided on the hydraulic pump shaft 20. The gear ratio of the gears 51 and 53 on the input splitting side is larger than the gear ratio of the gears 50 and 52 on the output splitting side. Therefore, even though the output shaft 5 is speed-changed by the planetary gear device 8, the hydraulic pump 16 at the time of input splitting is
A sufficient amount of discharge can be ensured.

The switching means 21 is not limited to a hydraulic clutch type, and various other modifications are possible, such as a manual bite clutch type.

(Effect of the invention) According to the invention, since the switching means 21 for selectively connecting the hydraulic pump 16 of the hydrostatic transmission 15 to the input shaft 3 and the output shaft 5 is provided,
You can arbitrarily select between the output split type and the input split type as needed. Therefore, by selecting the output split type when driving at high speeds and the input split type when driving at low speeds, the output split type and input split type can be selected as required. High transmission efficiency can be obtained and versatility is improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a sectional view of the switching means, FIG. 3 is a sectional view showing another embodiment, and FIG. 4 is a sectional view of the switching means. 1... Crankshaft, 3... Input shaft, 5... Output shaft, 8... Planetary gear device, 14A... Ring gear, 15... Hydrostatic transmission, 16... Hydraulic pump, 21... Switching Means, 23, 24...hydraulic clutch.

Claims (1)

[Scope of utility model registration request] A planetary gear device 8 that transmits power from the input shaft 3 to the output shaft 5, a hydraulic pump 16, and a hydraulic motor 1.
7 and a hydrostatic transmission 15 that controls the rotation of one of the three elements constituting the planetary gear device 8, the hydraulic pressure of the hydrostatic transmission 15 is pump 16
A vehicle transmission characterized in that a switching means 21 is provided for selectively connecting the input shaft 3 and the output shaft 5 to the input shaft 3 and the output shaft 5.