JPH10122336A - Hydro-mechanical transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydro-mechanical transmission which can high efficiently transmit power at high speed running time by increasing traction force at starting and low speed running time and improving running operability. SOLUTION: A hydro-mechanical power transmitting device capable of continuously variably transmitting power is constituted by a planet gear differential machine 10 driven by an engine 1 and an oil hydraulic motor 3 by driving an oil hydraulic pump 2 by the engine 1, 1st-speed gear 23 having a 1st-speed clutch 22 and a reverse gear 33 having a reverse clutch 32. By the engine 1, through a 2nd-speed gear 6, a 2nd-speed gear 25 having a 2nd-speed clutch 24 is driven, to constitute a mechanical power transmitting device. At low speed running time, the 1st-speed clutch 22 or reverse clutch 32 is turned on, variable speed running is steplessly made by the hydro-mechanical power transmitting device, at high speed time, the 2nd-speed clutch 24 is turned on, running is high efficiently performed by the mechanical power transmitting device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic-mechanical transmission, and more particularly to a hydro-mechanical transmission at a low speed and a mechanical transmission at a high speed. And a hydraulic-mechanical transmission for transmitting the torque.

[0002]

2. Description of the Related Art Conventionally, various types of hydraulic-mechanical transmissions have been used, and examples thereof are Japanese Patent Application Nos. 2-330214 and 8-150257.
And Japanese Patent Application No. 63-133765.

As shown in the schematic diagram of FIG. 6, a variable displacement type hydraulic pump 2 driven by an engine 1 and a hydraulic motor 3 are connected by piping (not shown) as proposed in Japanese Patent Application No. 2-330214. It has a hydrostatic power transmission. A reverse planetary gear train 51 having a reverse clutch 50 between the engine 1 and the output shaft 60, a forward planetary gear train 53 having a forward clutch 52, and a second A second-speed planetary gear train 55, a third-speed planetary gear train 57 having a third-speed clutch 56,
A speed clutch 58 and a planetary gear type differential 59 are provided, and the planetary gear type differential 59 is driven by the hydraulic motor 3 to constitute a hydraulic-mechanical power transmission device.

Next, the operation will be described. In the case of the first forward speed and the first reverse speed, the first speed clutch 58 is engaged, and the output shaft 60 is driven by the hydraulic motor 3 via the planetary gear type actuator 59. That is, power is transmitted by the hydrostatic power transmission device. In the case of the second forward speed and the third forward speed, the forward clutch 52 and the second speed clutch 5
The fourth or third speed clutch 56 is engaged, and the engine 1
The output shaft 60 is driven to rotate forward by a second-speed planetary gear train 55 or a third-speed planetary gear train 57 driven by the motor and a planetary gear type actuator 59 driven by the hydraulic motor 3.
That is, power is transmitted by the hydraulic-mechanical power transmission device. In the case of the second reverse speed and the third reverse speed, the reverse clutch 50 and the second speed clutch 54 or the third speed clutch 56 are engaged, and the output shaft 60 is reversely driven together with the planetary gear type actuator 59. I do. That is, power is transmitted by the hydraulic-mechanical power transmission device.

In this case, since the input shaft, the intermediate shaft and the output shaft are arranged on the same shaft, the lateral dimension of the transmission can be reduced as in the case of the conventional mechanical transmission. Can be mounted on major crawler vehicles without major design changes. In addition, the crawler-type vehicles of the same class have mounting compatibility with other transmissions, and can be freely selected in combination with the existing crawler steering device.

Japanese Patent Application No. 8-150257 proposes a mechanical transmission connected to an output shaft of an engine and having a plurality of gear stages, a hydraulic pump driven by the engine, and a hydraulic pump. And a hydraulic motor that generates a torque by receiving the discharge oil of the hydraulic transmission, and a control device that controls switching of a speed stage in the mechanical transmission according to the vehicle speed. The present invention relates to a control device and a control method.

The purpose is to use a hydraulic transmission for the low speed stage and a mechanical transmission for the high speed stage independently, and reduce the peak torque generated when shifting with the mechanical transmission. Thus, the clutch pack is downsized and the peak torque during shifting is reduced to improve durability.

Japanese Patent Application No. 63-133765 proposes a mechanical transmission driven by an engine,
A hydraulic transmission comprising a hydraulic pump driven by the engine and a hydraulic motor which operates by receiving oil discharged from the hydraulic pump; and a mechanical transmission in a range where the rotation speed of the output shaft is higher than a predetermined value. In a small range, the present invention relates to a mechanical hydraulic power transmission device that transmits power by a hydraulic power transmission device to improve transmission efficiency and smoothly control an output rotation speed between forward and reverse rotations, and a control method thereof.

[0009]

However, in the device proposed in Japanese Patent Application No. 2-330214, the transmission efficiency is poor at the time of starting or at a low speed stage because the device is driven by a hydrostatic power transmission device. Therefore, (1) Traction force is low and acceleration is poor. (2) Loss is large and heat generation is large due to poor efficiency. Therefore, the cooling capacity increases and the cost also increases. (3) A dedicated speed stage for the hydraulic power transmission is required,
Therefore, the transmission becomes large and the cost is high. In addition, since the power is transmitted by the hydraulic-mechanical power transmission device at the high speed stage, (4) a differential section dedicated to the high speed stage is required, and the transmission becomes complicated, large, and costly. (5) Transmission efficiency is better than hydraulic type but lower than mechanical type. (6) At the maximum speed, the hydraulic motor rotates at the maximum speed, and the noise is loud. There is a problem.

[0010] Japanese Patent Application No. 8-150257 and Japanese Patent Application No. Sho 6
The one proposed in Japanese Patent No. 3-133765 has a problem in that the transmission efficiency is poor at the time of starting or at a low speed stage because it is driven by a hydrostatic power transmission device.

The present invention has been made in view of the above-mentioned problems, and has a high traction force at the time of starting and running at a low speed, has good running operability, and can transmit power with high efficiency at a high speed running. It is an object of the present invention to provide a small-sized, low-cost hydraulic-mechanical transmission.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, in a hydraulic-mechanical transmission according to the present invention, there is provided a hydrostatic transmission in which a variable displacement hydraulic pump and a hydraulic motor are fluidly connected. Power transmission device and a mechanical power transmission device composed of a plurality of gear trains including a differential planetary gear mechanism, and both power transmission devices enable the power of the prime mover to be transmitted to the output shaft in a continuously variable transmission. In a hydraulic-mechanical transmission, when the output shaft rotation speed is equal to or lower than a predetermined rotation speed, the power of the prime mover is transmitted between a hydrostatic power transmission device and a differential planetary gear mechanism of the mechanical power transmission device, and the output shaft is When the rotation speed exceeds a predetermined rotation speed, the power of the prime mover is transmitted by a gear train other than the differential planetary gear mechanism.

[0013] Therefore, during low-speed running, the traction force is increased by the hydraulic-mechanical power transmission device, and particularly, the starting torque at the time of starting is increased, and the acceleration is improved. Also, during low-speed traveling and work, hydraulic-mechanical power transmission transmits power in a continuously variable speed to ensure good traveling operability and reduce loss. Efficient power transmission becomes possible. Therefore, it is possible to reduce the noise during high-speed running, and the cooling capacity is small and the cost is low.

A first shaft connecting the output shaft of the prime mover and the input shaft of the hydraulic pump, a planetary gear type differential arranged on the first shaft, and a first shaft are provided in parallel with the first shaft. A second shaft transmitted through a gear, a first-speed clutch and a second-speed clutch disposed on the second shaft for interrupting power from the first shaft, and in parallel with the first shaft. A third shaft transmitted through a gear, a reverse clutch disposed on the third shaft and intermittently driving power from the first shaft, and disposed in parallel with the third shaft. An output shaft and a gear fixed to the second shaft, the third shaft, and the output shaft, respectively, and sequentially transmitting power selected by the clutches to the output shaft are provided.

Therefore, by connecting and disconnecting each clutch, the first speed, the second speed, and the reverse speed can be arbitrarily selected and the output of the prime mover can be transmitted to the output shaft, so that the operation is easy. In addition, a hydraulic-mechanical transmission with a simple structure, small size and low cost can be obtained.

Further, a rotation speed detection sensor for detecting the rotation speed of the output shaft, and control for transmitting an ON-OFF control signal to the first speed clutch and the second speed clutch in response to a signal from the rotation speed detection sensor And a device.

Therefore, ON / OFF control of the first-speed clutch and the second-speed clutch is performed according to the number of revolutions of the output shaft, and it is possible to automatically perform the speed change control.

Further, a hydraulic-mechanical power transmission device for transmitting power during first speed traveling and reverse traveling and a mechanical power transmission device for transmitting power during second speed traveling are provided. I have.

Therefore, the power can be transmitted in a continuously variable speed by the hydraulic-mechanical power transmission device at the time of work or the like, so that the workability is good, and at the time of high-speed traveling, the mechanical power transmission device provides high efficiency. Power can be transmitted.

Further, the planetary gear type differential machine drives the second shaft via a sun gear fixed to the first shaft, an annular gear driven by a hydraulic motor, and a first speed clutch, or And a carrier for driving a third shaft via a reverse clutch, and a second speed gear for driving a second shaft via a second speed clutch is fixed to the first shaft.

Therefore, the first speed or the reverse is driven by the hydraulic-mechanical power transmission device by driving the hydraulic motor and turning on the first speed clutch or the reverse clutch, and the second speed clutch is turned on by turning on the second speed clutch. The second speed is driven by a mechanical power transmission device, and efficient power transmission is performed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a hydraulic-mechanical transmission according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic side view showing the configuration of the transmission, and FIG. 2 is a schematic front view. The engine 1 and a variable displacement hydraulic pump 2 (hereinafter, referred to as a hydraulic pump 2) are connected by a first shaft 4, and the hydraulic pump 2 and a variable displacement hydraulic motor 3 (hereinafter, referred to as a hydraulic motor 3) are connected by piping. 5 are connected. A planetary gear type differential 10 is arranged on one side of the first shaft 4 on the side of the hydraulic pump 2, and a sun gear 11 thereof is fixedly provided, and a second speed first gear is provided on the other side of the engine 1. 6 is fixed. The planetary gear differential 10 includes a sun gear 11, an annular gear 12, and a carrier 14 that supports the planetary gear 13 and has a carrier gear 15, which meshes with the motor output gear 7 of the hydraulic motor 3. ing. The hydraulic pump 2 and the hydraulic motor 3 are mounted side by side on the case 8.

A second shaft 20 is provided in parallel with the first shaft 4, and a driving first gear 21 is fixedly provided at a central portion thereof. A first speed gear 23 is rotatably mounted on one side of the second shaft 20 via a first speed clutch 22 and meshes with the carrier gear 15. On the other side, a second speed second gear 25 is rotatably disposed via a second speed clutch 24, and meshes with the second speed first gear 6. The drive first gear 21 and the first speed gear 23 turn the first speed clutch 22 ON-
The first drive gear 21 and the second speed second gear 25 connect the second speed clutch 24 to ON-OF by being turned off.
It is designed to be interrupted by F.

A third shaft 30 is provided in parallel with the first shaft 4, and a second driving gear 31 is fixedly provided at a central portion thereof and meshes with the first driving gear 21. And the third shaft 30
A reversing gear 33 is rotatably mounted on one side via a reversing clutch 32 and meshes with the carrier gear 15. The reverse gear 33 and the first speed gear 23 do not mesh with each other as shown in FIG. Drive second gear 31 and reverse gear 3
3 is interrupted by turning the reverse clutch 32 ON and OFF.

An output shaft 40 is provided in parallel with the third shaft 30, and an output gear 41 is fixed at the center of the output shaft 40 and meshes with the drive second gear 31. A parking brake 42 is provided on the other side of the output shaft 40. A rotation speed detection sensor 43 is arranged at an end of the output shaft 40 and is connected to a control device 44. The control device 44 includes a transmission operation lever 45 and a plurality of clutch operation valves 4.
6 (only one is shown in the figure)
The first speed clutch 22 and the second speed clutch are transmitted by receiving signals from the rotation speed detection sensor 43 or the transmission operation lever 45, and transmitting control signals to the clutch operation valves 46 of the respective forward speeds and reverse speeds and respective speed stages. The on / off control of the reverse clutch 24 and the reverse clutch 32 is performed. The forward gear (F) and the first gear (F)
1) There are four positions: second speed (F2) and reverse (R).
In this embodiment, up to the second forward speed is illustrated.
High speed gears of 3rd speed or higher can be implemented in the same manner, and gears on the input shaft corresponding to the speed gears and a pair of gears and clutches can be added to each gear. Can be added. In addition, the planetary gear type differential of the first shaft may be used not only for the input from the hydraulic motor to the ring gear and the output from the carrier, but also for the input from the hydraulic motor to the ring gear and the output from the sun gear, for example. Further, an input from the hydraulic motor to the sun gear and an output from the ring gear may be used. Needless to say, there are various combinations as shown in Table 1.

[0026]

[Table 1]

The illustration of this embodiment shows the types shown in Table 1.

With the above configuration, the structure is simplified, the entire transmission is reduced in size, the space required is reduced, and the cost is reduced.

The operation of the transmission will be described below. (1) When the transmission operation lever 45 is set to the first forward speed (F1) position, the control device 44 transmits a control signal to the clutch operation valve 46 to turn on the first speed clutch 22 and to operate the second speed clutch 24 and reverse. The clutch 32 is turned off.
As a result, as shown in FIG. 3, the output of the engine 1 is controlled by the hydraulic motor 3 driving the annular gear 12 to drive the planetary gear type differential 1
0 and the sun gear 1 driven by the engine 1
1 and the carrier 14 is driven. Carrier gear 15
Drives the second shaft 20 via the first speed gear 23 and the first speed clutch 22, and drives the first driving gear 21-the second driving gear 3
1- The output shaft 40 is driven forward at low speed through the output gear 41 sequentially. That is, the output shaft 40 is connected to the hydraulic-mechanical power transmission device (the output of the hydraulic motor 3 and the planetary gear type differential 10
Driven by a stepless speed change. Therefore,
The running performance is good, work is easy, and the power is transmitted with higher efficiency than the hydraulic power transmission device, so there is less loss than the conventional one, and the cooling capacity is small,
Small footprint and low cost.

(2) When the transmission operation lever 45 is set to the second forward speed (F2) position, the control device 44 sends a control signal to the clutch operation valve 46 to turn the second speed clutch 24 to the O position.
N, the first speed clutch 22 and the reverse clutch 32 are turned off. Further, the swash plate is controlled so that the discharge amount of the hydraulic pump 2 becomes zero, and the rotation of the hydraulic motor 3 is stopped. As a result, as shown in FIG. 4, the output of the engine 1 is the engine 1-second speed first gear 6-second speed second gear 25-
The second shaft 20 is driven sequentially through the second speed clutch 24, and the output shaft 40 is forwardly driven at high speed through the first driving gear 21 -the second driving gear 31 -the output gear 41. That is, the output shaft 40 is driven by the mechanical power transmission device. Therefore, power can be transmitted with high efficiency and little loss, and the noise is low because the hydraulic motor is stopped during high-speed running.

(3) Move the transmission operating lever 45 forward (F)
When in the position, the controller 44 operates the clutch operation valve 46.
, A first speed clutch 22 is turned on,
The second speed clutch 24 and the reverse clutch 32 are turned off. As a result, as described above, the output shaft 40 is normally driven at low speed by the hydraulic-mechanical power transmission device. (FIG. 3
When the output shaft 40 exceeds a predetermined rotation speed, the control device 44 receives a signal from the rotation speed detection sensor 43, transmits a control signal to the clutch operation valve 46, and turns off the first speed clutch 22 and the reverse clutch 32. Then, the second speed clutch 24 is turned on. At the same time, the swash plate is controlled so that the discharge amount of the hydraulic pump 2 becomes zero, and the rotation of the hydraulic motor 3 also stops. As a result, as described above, the output shaft 40 is driven to rotate forward at high speed by the mechanical power transmission device (see FIG. 4), and the automatic transmission is shifted from the first speed to the second speed.

(4) When the shift operation lever 45 is set to the reverse (R) position, the control device 44 sends a signal to the clutch operation valve 46 to turn off the first speed clutch 22 and the second speed clutch 24, and 32 is turned ON.
As a result, as shown in FIG. 5, the output of the engine 1 causes the hydraulic motor 3 to drive the ring gear 12 to drive the planetary gear type differential 1
0 and the sun gear 1 driven by the engine 1
1 and the carrier 14 is driven. Carrier gear 15
Drives the third shaft 30 via the reverse gear 33 and the reverse clutch 32, and reversely drives the output shaft 40 at low speed via the second drive gear 31 and the output gear 41. That is, the output shaft 40 is driven at a continuously variable speed by the hydraulic-mechanical power transmission device. Therefore, it is easy to work at the time of work or the like, and power is transmitted with higher efficiency than the hydraulic power transmission device.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a configuration of a hydraulic-mechanical transmission according to the present invention.

FIG. 2 is a schematic front view showing a configuration of a hydraulic-mechanical transmission according to the present invention.

FIG. 3 is a power system diagram of the hydraulic-mechanical transmission of the present invention at the first forward speed.

FIG. 4 is a power system diagram of the hydraulic-mechanical transmission of the present invention at the second forward speed.

FIG. 5 is a power system diagram when the hydraulic-mechanical transmission according to the present invention moves backward.

FIG. 6 is a schematic diagram showing a configuration of a conventional hydraulic-mechanical transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Hydraulic pump 3 Hydraulic motor 4 1st shaft 6 2nd speed 1st gear 7 Motor output gear 10 Planetary gear type differential 11 Sun gear 12 Ring gear 13 Planetary gear 14 Carrier 15 Carrier gear 20 2nd shaft 21 Drive 1 gear 22 1st speed clutch 23 1st speed gear 24 2nd speed clutch 25 2nd speed 2nd gear 30 3rd shaft 31 drive 2nd gear 32 reverse clutch 33 reverse gear 40 output shaft 41 output gear 43 rotation speed detection sensor 44 Control device 45 Transmission operation lever 46 Clutch operation valve

Claims (5)

[Claims] 1. A hydrostatic power transmission device in which a variable displacement hydraulic pump and a hydraulic motor are fluidly connected, and a mechanical power transmission device including a plurality of gear trains including a differential planetary gear mechanism. In a hydraulic-mechanical transmission capable of continuously transmitting the power of a prime mover to an output shaft by a power transmission device, the power of the prime mover is transmitted by hydrostatic power transmission when the output shaft rotational speed is equal to or less than a predetermined rotational speed. The power is transmitted between the device and the differential planetary gear mechanism of the mechanical power transmission device, and the power of the prime mover is transmitted by a gear train other than the differential planetary gear mechanism when the output shaft rotation speed exceeds a predetermined rotation speed. Hydraulic pressure characterized by
Mechanical transmission. 2. A power transmission device comprising: a hydrostatic power transmission device in which a variable displacement hydraulic pump and a hydraulic motor are fluidly connected; and a mechanical power transmission device comprising a plurality of gear trains. -Mechanical transmission capable of continuously transmitting the hydraulic pressure to the output shaft, wherein the first shaft connecting the output shaft of the prime mover and the input shaft of the hydraulic pump is connected.
A shaft, a planetary gear differential arranged on the first shaft, a second shaft provided in parallel with the first shaft and transmitted through a gear, and arranged on the second shaft A first-speed clutch and a second-speed clutch for interrupting power from the first shaft; a third shaft provided in parallel with the first shaft and transmitted via a gear; A reverse clutch arranged and disconnected from the first shaft, an output shaft arranged in parallel with the third shaft, and fixedly attached to the second shaft, the third shaft and the output shaft, respectively.
A gear for sequentially transmitting power selected by the clutches to the output shaft. 3. A rotation speed detection sensor for detecting a rotation speed of an output shaft, and a first sensor for receiving a signal from the rotation speed detection sensor.
3. The hydraulic-mechanical transmission according to claim 1, further comprising a control device for transmitting an ON-OFF control signal to the speed clutch and the second speed clutch. 4. A hydraulic-mechanical power transmission device for transmitting power during first speed traveling and reverse traveling, and a mechanical power transmission device for transmitting power during second speed traveling and above. The hydraulic-mechanical transmission according to any one of claims 1, 2 and 3, wherein 5. A planetary gear type differential of a mechanical transmission,
A sun gear fixed to a first shaft, an annular gear driven by a hydraulic motor, and a carrier for driving a second shaft via a first speed clutch or for driving a third shaft via a reverse clutch The hydraulic pressure according to any one of claims 1 to 4, wherein a second speed gear that drives the second shaft via a second speed clutch is fixed to the first shaft. A mechanical transmission;