JP3209153B2 - Hydromechanical transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission used for buses, trucks, various construction machines, various industrial machines, etc., and more particularly to a continuously variable transmission called a hydromechanical transmission.

[0002]

BACKGROUND ART Hydromechanical transmissions include a mechanical transmission having a clutch mechanism and a planetary gear mechanism in a power transmission path connecting an input shaft and an output shaft, and a hydrostatic transmission having a hydraulic pump and a hydraulic motor. Are arranged side by side to continuously change the speed. Various improvements have been attempted from the viewpoint of improving the transmission efficiency of the entire hydromechanical transmission.

FIG. 1 is a schematic diagram of a hydromechanical transmission disclosed in Japanese Patent Application No. 8-54434 filed on Mar. 12, 1996 by the same applicant as the present application, and FIG. FIG. 4 is a diagram showing a relationship between a shift mode of FIG. The hydromechanical transmission disclosed in this prior application has been changed from a conventional three-stage shift mode to a four-stage shift mode to increase the number of lock-up operation points. With reference to FIGS. 1 and 2, a schematic configuration and operation of a hydromechanical transmission disclosed in Japanese Patent Application No. 8-54434 will be described.

[0004] In the hydromechanical transmission, a mechanical transmission 3 and a hydrostatic transmission 4 are juxtaposed in a power transmission path connecting an input shaft 1 and an output shaft 2. The mechanical transmission 3 includes a first planetary gear mechanism 7, a second planetary gear mechanism 8, a third planetary gear mechanism 15, a first clutch mechanism 10, a second clutch mechanism 11, a third clutch mechanism 12, A fourth clutch mechanism 13 and a fifth clutch mechanism 14 are provided.

[0005] The hydrostatic transmission 4 includes a hydraulic pump 5 having a swash plate 5a and a hydraulic motor 6 having a swash plate 6a. The output of the hydraulic motor 6 is
The power is transmitted to the sun gear 16 of the first planetary gear mechanism 7 via the gears 18 and 17.

The angle of the swash plate 5a of the pump 5 is variable. On the other hand, the angle of the swash plate 6a of the hydraulic motor 6 can be switched in two stages. The motor shaft fixing mechanism 19 is provided so as to be engageable with the gear 18, and when engaged with the gear 18, stops rotation of the gear 18, that is, rotation of the output shaft of the hydraulic motor 6.

In the first mode in the low speed range, only the first clutch mechanism 10 and the fourth clutch mechanism 13 are connected.

In the second mode in the middle / low speed range, only the second clutch mechanism 11 and the fourth clutch mechanism 13 are connected.

In the third mode in the middle and high speed range, only the third clutch mechanism 12 and the fourth clutch mechanism 13 are connected.

In the fourth mode in the high speed range, the fifth clutch mechanism 14 and the third clutch mechanism 12 are connected. At the middle point of the fourth mode, the swash plate 6a of the hydraulic motor 6
Is switched, and the rotation speed of the output shaft of the hydraulic motor 6 is increased. Accordingly, the rotation speed of the output shaft 2 is also increased.

Incidentally, the fourth clutch mechanism 1 in the first mode
The connection of the third clutch mechanism 12 in the third and fourth modes is intended to synchronize the rotational speed of the tubular member 52 at the next switching point, and does not transmit the rotational force.

When the vehicle maintains a constant speed, it is not preferable in terms of transmission efficiency to continue the normal operation of transmitting power via both the mechanical transmission 3 and the hydrostatic transmission 4.
In such a case, power transmission via the hydrostatic transmission 4 is cut off, and power transmission from the input shaft 1 to the output shaft 2 is stopped.
It is preferable that the lock-up operation be performed by switching to the operation through only the lock-up operation.

In FIG. 2, a switching speed corresponding to the switching speed ratio between the modes, an intermediate speed corresponding to each central speed ratio at which the variable swash plate 5a of the hydraulic pump 5 is positioned at the neutral position, , And the maximum speed corresponding to the maximum speed ratio of the fourth mode, the lock-up operation is performed when there are seven specific speeds.

In the lock-up operation at the switching speed, the first clutch mechanism 10, the second clutch mechanism 11, and the fourth clutch mechanism 13 are connected, and the variable swash plate 5a is connected to the swash plate 6a of the hydraulic motor 6. This is done by maintaining the same swash plate angle (in absolute value). Since the swash plate 5a of the hydraulic pump 5 and the swash plate 6a of the hydraulic motor 6 have the same swash plate angle, the output from the hydrostatic transmission is not transmitted to the mechanical transmission 3. Therefore, the rotation transmission from the input shaft 1 to the output shaft 2 is performed by the mechanical transmission 3
Only through.

In the lock-up operation at the intermediate speed in the second mode, the variable swash plate 5a of the hydraulic pump 5 is maintained at the neutral position when the second clutch mechanism 11 and the fourth clutch mechanism 13 are connected. . In this state, the output shaft of the hydraulic motor 6 is in a non-rotating state, and the rotation transmission from the input shaft 1 to the output shaft 2 is performed only through the mechanical transmission 3.

By activating the motor shaft fixing mechanism 19 (see FIG. 1), the rotational force acting on the motor shaft is removed, and the power loss of the hydrostatic transmission can be further reduced.

In the lock-up operation at the switching speed for switching from the second mode to the third mode, the second clutch mechanism 11, the third clutch mechanism 12, and the fourth clutch mechanism 13 are maintained in the connected state, and the hydraulic pump 5 is operated.
Is maintained at the same swash plate angle as the swash plate 6a of the hydraulic motor 6.

In the lock-up operation at the intermediate rotation speed in the third mode, the third clutch mechanism 12 and the fourth clutch mechanism 13 are maintained in the connected state, and the variable swash plate 5a of the hydraulic pump 5 is maintained at the neutral position. , By operating the motor shaft fixing mechanism 19.

The lock-up operation at the switching speed at which the mode is switched from the third mode to the fourth mode includes a third clutch mechanism 12, a fourth clutch mechanism 13, and a fifth clutch mechanism 14.
Is maintained in the connected state, and the variable swash plate 5a of the hydraulic pump 5 is maintained at the same swash plate angle (in absolute value) as the swash plate 6a of the hydraulic motor 6.

In the lock-up operation at the intermediate speed in the fourth mode, the variable swash plate 5a of the hydraulic pump 5 is maintained at the neutral position while the fifth clutch mechanism 14 and the third clutch mechanism 12 are connected, and This is performed by operating the motor shaft fixing mechanism 19.

In the lock-up operation at the maximum rotation speed, the second clutch mechanism 11, the third clutch mechanism 12, and the fifth clutch mechanism 14 are maintained in a connected state.
This is performed by maintaining the variable swash plate 5a at the same maximum swash plate angle as the swash plate 6a of the hydraulic motor 6.

FIG. 3 is a schematic diagram of a hydromechanical transmission disclosed in Japanese Patent Application No. 9-123780 filed on May 14, 1997 by the same applicant as the present application. The hydromechanical transmission includes a motor shaft idler 20. The motor shaft idler 20 disconnects the output shaft of the hydraulic motor 6 from the gear 18 as necessary.

When the operation mode is switched to the lock-up operation at the gear ratio corresponding to the switching speed of the operation mode, the motor shaft idling mechanism 20 disconnects the output shaft of the hydraulic motor 6 from the gear 18. As a result, the motor shaft and the mechanical transmission 3 are separated from each other, and power transmission from the motor shaft to the mechanical transmission is completely cut off, while the motor shaft can freely idle. Therefore, the variable swash plate 5a of the hydraulic pump 5 is controlled to the neutral position at the swash plate angle of 0 to stop the rotation of the hydraulic motor 6, thereby making it possible to reduce the power loss of the hydrostatic transmission unit. .

[0024]

As disclosed in the above two prior applications, in order to improve the transmission efficiency of the hydromechanical transmission as a whole, a swash plate angle switching mechanism of a hydraulic motor, a motor shaft fixing mechanism and A motor shaft idling mechanism is required. However, if these three mechanisms are employed at the same time, the entire apparatus becomes complicated, the weight increases, and the cost also increases.

In the hydromechanical transmission disclosed in Japanese Patent Application No. 8-54434,
In the high-speed mode, the rotation of the motor shaft is increased by switching the swash plate angle of the swash plate 6a of the hydraulic motor 6.
With such high-speed rotation of the motor shaft, power loss increases. In addition, since the high-speed rotation must be performed within the range of the allowable rotation speed of the hydraulic motor of the hydrostatic transmission, the motor rotation speed at low speed is limited, and the torque at low speed operation requiring a large output torque is sufficient. Can not be raised.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the transmission efficiency of a hydro-mechanical transmission and to reduce the size and weight of the entire apparatus to reduce the cost. That is.

[0027]

SUMMARY OF THE INVENTION The present invention provides a hydraulic transmission having a clutch and a planetary gear mechanism and a hydraulic pump and a hydraulic motor in a power transmission path connecting an input shaft and an output shaft. It assumes a hydromechanical transmission with a static transmission.

[0028]

[0029]

According to the first aspect of the present invention, there is provided a hydraulic transmission, comprising: an output shaft of a hydraulic motor of a hydrostatic transmission; and a planetary gear mechanism of a mechanical transmission.
Low-speed connection means and high-speed connection means for connecting them at different speed ratios are provided in parallel. The low-speed connection means includes a low-speed gear and a low-speed clutch mechanism that removably connects the low-speed gear to the output shaft of the hydraulic motor. The high-speed connecting means includes a high-speed gear, and a high-speed clutch mechanism that removably connects the high-speed gear to the output shaft of the hydraulic motor. The hydromechanical transmission concerned
Are the first mode in the low-speed range, the second mode in the middle-low speed range,
Four highs in the third mode in the high speed range and the fourth mode in the high speed range
It is to be operated in the speed mode. During the lock-up operation at the switching point of each mode, both the low-speed gear and the high-speed gear are separated from the output shaft of the hydraulic motor.
During the lock-up operation at the intermediate point between the second, third and fourth modes where the angle of the swash plate of the hydraulic pump is 0 °, both the low-speed gear and the high-speed gear are connected to the output shaft of the hydraulic motor. I do.

According to the first aspect of the present invention, by switching from the low speed connection means to the high speed connection means at the intermediate point of the high speed mode, the output transmitted from the hydrostatic transmission to the planetary gear mechanism of the mechanical transmission is increased. Can be faster. Therefore,
The swash plate angle of the hydraulic motor of the hydrostatic transmission can be kept fixed. Also,
It is easy to connect and disconnect the output shaft of the hydraulic motor and the gear. In addition, connection of low-speed gear and high-speed gear
By simply controlling the disconnection, the rotation of the output shaft of the hydraulic motor can be made idle or fixed.

[0032]

[0033]

[0034]

[0035]

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 4, an overall configuration of a hydromechanical transmission according to the present invention will be described. Note that, in FIG. 4, components denoted by the same reference numerals as those shown in FIG. 1 indicate the same or corresponding elements.

In the hydromechanical transmission, a mechanical transmission 3 and a hydrostatic transmission 4 are arranged side by side in a power transmission path connecting the input shaft 1 and the output shaft 2.

The mechanical transmission 3 has a first
A planetary gear mechanism 7, a second planetary gear mechanism 8, a third planetary gear mechanism 15, a first clutch mechanism 10, a second clutch mechanism 11, a third clutch mechanism 12, a fourth clutch mechanism 13, A fifth clutch mechanism 14;

The first planetary gear mechanism 7 includes a sun gear 16 and
The planetary gear 3 that revolves around the sun gear 16
9, an internal gear 40 that meshes with the planetary gear 39, and a carrier 41 that holds the plurality of planetary gears 39.

The second planetary gear mechanism 8 includes a sun gear 44 fixed to the intermediate shaft 46, a plurality of planetary gears 43 that revolve by meshing with the sun gear 44, and an internal gear 42 meshing with the planetary gear 43. , A carrier 45 for holding a plurality of planetary gears 43. The carrier 45 and the internal gear 40 of the first planetary gear mechanism 7 are fixed. As shown, the carrier 45 and the output shaft 2 are fixed. The carrier 41 of the first planetary gear mechanism 7 and the internal gear 42 of the second planetary gear mechanism 8 are fixed.

The third planetary gear mechanism 15 includes a sun gear 47 fixed to the output shaft 1, a plurality of planetary gears 48 that revolve and mesh with the sun gear 47, and an internal gear 49 that meshes with the planetary gears 48. Prepare. The internal gear 49 is fixed to the non-rotating part 53.

The first clutch mechanism 10 connects and disconnects the tubular member 50 fixed to the carrier 41 of the first planetary gear mechanism 7 and the internal gear 42 of the second planetary gear mechanism 8 to the non-rotating part 51. The separation is performed.

The second clutch mechanism 11 includes a cylindrical member 52
And the intermediate shaft 46 are connected and disconnected.

The third clutch mechanism 12 connects and disconnects between the tubular member 52 and the tubular member 50.

The fourth clutch mechanism 13 connects and disconnects the cylindrical member 52 from the carrier 54 holding the plurality of planetary gears 48 of the third planetary gear mechanism.

The fifth clutch mechanism 14 connects and disconnects the input shaft 1 and the intermediate shaft 46.

The hydrostatic transmission 4 includes a hydraulic pump 5 and a hydraulic motor 6. The rotation of the input shaft 1 is transmitted to the pump shaft 37 of the hydraulic pump 5 via the gears 35 and 36. Swash plate 5 of hydraulic pump 5
The swash plate angle of a is variable. On the other hand, the swash plate angle of the swash plate 6a of the hydraulic motor 6 is fixed.

Between the motor shaft 38 of the hydraulic motor 6 and the sun gear 16 of the first planetary gear mechanism 7 of the mechanical transmission, low-speed connection means and high-speed connection means for connecting them at different speed ratios are arranged in parallel. Is provided. Specifically, the sun gear 16 has a relatively large diameter gear 17.
And a gear 30 having a relatively small diameter are fixed. The low-speed connection means includes a low-speed gear 31 arranged to mesh with the large-diameter gear 17, and a low-speed clutch mechanism 33 that removably connects the low-speed gear 31 to an output shaft 38 of the hydraulic motor 6. Is provided. The high-speed connection means includes a high-speed gear 32 arranged to mesh with a relatively small-diameter gear 30, and a high-speed clutch for detachably connecting the high-speed gear 32 to an output shaft 38 of the hydraulic motor 6. And a mechanism 34.

FIG. 5 shows the connection / disconnection state of the low-speed connection means and the high-speed connection means. The bold line in the figure indicates the connection state, and the thin line indicates the disconnected state.

FIG. 6 is a diagram showing the operation status of each part in the four-stage shift mode. The operation of the hydromechanical transmission according to the present invention will be described with reference to FIGS.

(First Mode) In the first mode in the low speed range,
The first clutch mechanism 10 and the fourth clutch mechanism 13 are connected. Since the second clutch mechanism 11, the third clutch mechanism 12, and the fifth clutch mechanism 14 are each in the disengaged state, the rotation of the input shaft 1 is controlled by the tubular member 50.
And is not transmitted to the intermediate shaft 46. Therefore, the output shaft 2 is rotated only by the transmission force from the hydrostatic transmission 4.

In the first mode, as shown in FIG. 5A, the motor shaft 38 of the hydraulic motor 6 is connected to the low-speed gear 31 via the low-speed clutch mechanism 33. On the other hand, the high-speed clutch mechanism 34 includes the high-speed gear 32 and the motor shaft 3.
8 is separated.

In the first mode, the fourth clutch mechanism 13
Is connected to prepare for switching from the first mode to the second mode, and it is not always necessary to keep the fourth clutch mechanism 13 connected in the first mode.

According to the change in the swash plate angle of the variable swash plate 5a of the hydraulic pump 5, the rotation speed of the sun gear 16 to which the output of the hydrostatic transmission is transmitted also increases or decreases.

(Second Mode) In the second mode, the second clutch mechanism 11 and the fourth clutch mechanism 13 are connected. With this connection, the rotation of the input shaft 1 is transmitted to the second planetary gear mechanism 8 via the third planetary gear mechanism 15, the cylindrical member 52, and the intermediate shaft 46. Therefore, the output shaft 2 is rotated by a combined force of the transmission force from the intermediate shaft 46 via the second planetary gear mechanism 8 and the transmission force from the hydrostatic transmission 4 via the first planetary gear mechanism 7. .

In the second mode, as shown in FIG. 5A, the motor shaft 38 of the hydraulic motor 6 is
It is connected to the low-speed gear 31 via the low-speed clutch mechanism 33.

(Third Mode) In the third mode, the third clutch mechanism 12, the fourth clutch mechanism 13, and the low-speed clutch mechanism 33 are connected. The rotation of input shaft 1 is
The power is transmitted to the carrier 41 of the first planetary gear mechanism 7 via the third planetary gear mechanism 15, the tubular member 52, and the tubular member 50. Thus, the output shaft 2 transmits the transmission force from the tubular member 50 via the planetary gear 39 of the first planetary gear mechanism 7 and the transmission force from the hydrostatic transmission 4 via the sun gear 16 of the first planetary gear mechanism 7. Is rotated by the combined force of

(Fourth Mode) In the fourth mode, the fifth clutch mechanism 14 and the third clutch mechanism 12 are connected. In the first half region of the fourth mode, the low-speed clutch mechanism 33 is connected, and in the second half region, the high-speed clutch mechanism 34 is connected.

The rotation input from the input shaft 1 is transmitted as it is to the sun gear 44 of the second planetary gear mechanism 8 via the fifth clutch mechanism 14 and the intermediate shaft 46. Output shaft 2 is
It is rotated by a combined force of the transmission force from the carrier 45 of the second planetary gear mechanism 8 and the transmission force from the hydrostatic transmission 4 via the first sun gear 16 of the first planetary gear mechanism 7.

In the latter half of the fourth mode, FIG.
As shown in FIG. 7, the motor shaft 38 of the hydraulic motor 6 is connected to the high-speed gear 32 via the high-speed clutch mechanism 34. Therefore, as shown in FIG.
, The speed of the output shaft 2 is correspondingly increased.

(Lock-up operation) In FIG. 6, the switching speed corresponding to the switching speed ratio between the modes,
When the variable swash plate 5a is at seven specific rotational speeds, an intermediate rotational speed corresponding to each central speed ratio brought to the neutral position, and a maximum rotational speed corresponding to the maximum speed ratio in the fourth mode, Lock-up operation is performed. During this lock-up operation, power transmission via the hydrostatic transmission 4 is interrupted, and power transmission from the input shaft 1 to the output shaft 2 is assumed to be via only the mechanical transmission 3.

(Switching Speed) In the lockup operation at the switching speed at which the first mode is switched to the second mode, the first clutch mechanism 10, the second clutch mechanism 11, and the fourth clutch mechanism 13 are maintained in the connected state. At the same time, the variable swash plate 5a is maintained at the same swash plate angle (in absolute value) as the swash plate 6a of the hydraulic motor. The low-speed clutch mechanism 33 and the high-speed clutch mechanism 34 are both disengaged, as shown in FIG. 5C. Therefore, the motor shaft 3 of the hydraulic motor
8 and planetary gear mechanism 7 of mechanical transmission 3
Is disconnected, and idling of the motor shaft 38 is realized. Thus, the rotation of the hydraulic motor is stopped, the internal friction of the motor is suppressed, and the power loss can be reduced.

(Switching Speed) The lock-up operation at the intermediate speed in the second mode is performed by the second clutch mechanism 11.
And the fourth clutch mechanism 13 are maintained in the connected state, the variable swash plate 5a is maintained in the neutral position, and the low-speed clutch mechanism 33 and the high-speed clutch mechanism 34 are both connected as shown in FIG. This is done by setting the state. Since the motor shaft 38 is simultaneously coupled to both the low-speed gear 31 and the high-speed gear 32, the interaction of the motor shaft 38 fixes the rotation of the motor shaft. In this way, the torque acting on the hydraulic motor is released, the internal pressure of the hydrostatic transmission is reduced, and the power loss can be reduced.

(Switching Speed) In the lockup operation at the switching speed at which the second mode is switched to the third mode, the second clutch mechanism 11, the third clutch mechanism 12, and the fourth clutch mechanism 13 are maintained in the connected state. At the same time, the variable swash plate 5a is maintained at the same swash plate angle as the swash plate 6a of the hydraulic motor. At this time, both the low speed clutch 33 and the high speed clutch 34 are disengaged, so that the motor shaft 38 is idled.

(Intermediate Speed) The lock-up operation at the intermediate speed in the third mode is performed by the third clutch mechanism 12.
And the fourth clutch mechanism 13 is connected, the variable swash plate 5a is maintained at the neutral position, and the low-speed clutch 33
And the high-speed clutch 34 in the connected state. By connecting both the low speed clutch 33 and the high speed clutch 34, the motor shaft 38 is fixed.

(Switching Rotation Speed) In the lock-up operation at the switching rotation speed at which the mode is switched from the third mode to the fourth mode, the third clutch mechanism 12, the fourth clutch mechanism 13, and the fifth clutch mechanism 14 are brought into the connected state, and Swash plate 5a
Is maintained at the same swash plate angle (in absolute value) as the swash plate 6a of the hydraulic motor. At this time, the low-speed clutch mechanism 33 and the high-speed clutch mechanism 34 are both disengaged. Thus, idling of the motor shaft 38 is realized.

(Intermediate rotation speed) In the lockup operation at the intermediate rotation speed in the fourth mode, the variable swash plate 5a is maintained at the neutral position while the fifth clutch mechanism 14 and the third clutch mechanism 12 are connected, and the low speed This is performed by bringing both the clutch mechanism 33 and the high-speed clutch mechanism 34 into the connected state.

(Maximum Rotation Speed) The lock-up operation at the maximum rotation speed in the fourth mode is performed by the second clutch mechanism 1.
1, third clutch mechanism 12 and fifth clutch mechanism 14
Is connected, and the variable swash plate 5a is connected to the swash plate 6a of the hydraulic motor.
This is done by maintaining the same maximum swash plate angle as
At this time, since the low-speed clutch mechanism 33 and the high-speed clutch mechanism 34 are in the disengaged state, idling of the motor shaft 38 is realized.

In the above-described embodiment, two sets of gears for high speed and low speed are detachably connected to the motor shaft of the hydrostatic transmission via the clutch. However, if possible, a low-speed connection unit and a high-speed connection unit that can realize different gear ratios using other mechanisms may be configured.

[0070]

According to the first aspect of the present invention, a low-speed connection between the output shaft of the hydraulic motor of the hydrostatic transmission and the planetary gear mechanism of the mechanical transmission at different speed ratios. Since the means and the high-speed connection means are provided in parallel, the operation of the hydromechanical transmission can be extended to a high-speed region without increasing the rotation speed of the motor shaft. Further, since a swash plate switching mechanism or a variable mechanism of the hydrostatic transmission motor is not required, a great reduction in weight and cost can be achieved, including the use of an aluminum casing.

Further, even in a high-speed range, the rotation of the hydraulic motor can be maintained in a low range, so that friction and agitation loss due to the high-speed rotation of the motor can be reduced, and transmission efficiency can be improved. Also, since the motor does not need to be rotated at high speed, the pump, which was determined from the allowable rotation speed of the motor,
The number of rotations of the motor and the reduction ratio between the motor and the machine shaft can be changed, and it is possible to cope with the use of high torque without changing the capacity of the hydrostatic transmission.

[0072] Moreover, a slow connection means constituted by a low-speed gear and the low speed clutch mechanism, since the high-speed connection means is constituted by the high-speed gear and the high speed clutch mechanism, easily perform connecting and disconnecting operation And the structure can be simplified.

Further , since the speed of the output shaft is increased by increasing the speed of the transmission mode and connecting a high-speed gear in the latter half region of the high-speed mode, the output of the entire hydro-mechanical transmission can be increased, and the lock can be increased. The up operating point can be increased.

Further , since the idling and fixing of the output shaft of the hydraulic motor are realized by connecting and disconnecting the low-speed gear and the high-speed gear, the same applicant as the present application has filed a Japanese Patent Application No. Hei 8-108. There is no need to provide a special motor shaft fixing mechanism as disclosed in Japanese Patent Application No. 54434 or a special motor shaft idling mechanism as disclosed in Japanese Patent Application No. 9-123780. That is, the three operating mechanisms of the swash plate switching mechanism, the motor shaft fixing mechanism, and the motor shaft idler mechanism disclosed in the two prior applications can be two-system operating mechanisms of a low-speed gear and a high-speed gear. Therefore, it is possible to reduce the size, weight, and cost of the hydromechanical transmission.

[Brief description of the drawings]

FIG. 1 is a schematic view of a hydromechanical transmission disclosed in Japanese Patent Application No. 8-54434.

FIG. 2 is a diagram showing the operation of each part in each operation mode of the hydromechanical transmission.

FIG. 3 is a schematic diagram showing a part of a hydromechanical transmission disclosed in Japanese Patent Application No. 9-123780.

FIG. 4 is a schematic view of a hydromechanical transmission according to the present invention.

FIG. 5 is a diagram for explaining an operation state of low-speed connection means and high-speed connection means used in the hydromechanical transmission of the present invention.

FIG. 6 is a diagram for explaining the operation of each part in each operation mode of the hydromechanical transmission according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 input shaft 2 output shaft 3 mechanical transmission 4 hydrostatic transmission 5 hydraulic pump 5a swash plate 6 hydraulic motor 6a swash plate 31 low-speed gear 32 high-speed gear 33 low-speed clutch mechanism 34 high-speed clutch mechanism 38 motor shaft

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-101744 (JP, A) JP-A-8-277907 (JP, A) JP-A-50-8957 (JP, A) JP-A-54-957 35560 (JP, A) JP-A-2-221463 (JP, A) JP-A-9-242844 (JP, A) JP-A 10-318350 (JP, A) JP-B-49-41537 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 47/02-47/04

Claims (1)

(57) [Claims] A clutch mechanism (10, 11, 12, 1) is provided in a power transmission path connecting an input shaft (1) and an output shaft (2).
3, 14) and a mechanical transmission (3) equipped with a planetary gear mechanism (7, 8, 15), and a hydrostatic transmission (4) equipped with a hydraulic pump (5) and a hydraulic motor (6). In the installed hydromechanical transmission, different transmissions are provided between the output shaft (38) of the hydraulic motor (6) of the hydrostatic transmission (4) and the planetary gear mechanism (7) of the mechanical transmission (3). Low-speed connection means (31,3
3) and high-speed connecting means (32, 34) are provided in parallel. The low-speed connecting means relates to the low-speed gear (31) and the low-speed gear to the output shaft (38) of the hydraulic motor (6). A low-speed clutch mechanism (33) removably connected, wherein the high-speed connecting means engages and disengages the high-speed gear (32) with the output shaft (38) of the hydraulic motor (6). And a high-speed clutch mechanism (34) to be connected to the hydro-mechanical transmission.
In the first mode, the second mode in the middle and low speed range, and the third mode in the middle and high speed range
Mode and 4 speed modes in the high speed range
During the lock-up operation at the switching point of each mode, both the low-speed gear (31) and the high-speed gear (32) are connected to the output shaft (38) of the hydraulic motor (6). ), And at the time of lock-up operation at an intermediate point between the second, third and fourth modes in which the angle of the swash plate (5a) of the hydraulic pump (5) becomes 0 °, the low-speed gear (31) And a high speed gear (32) connected to the output shaft (38) of the hydraulic motor (6).