JP3090087B2 - Continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a bus, a truck,
Regarding continuously variable transmissions used in various construction machines or various industrial machines, in particular, a hydromechanical transmission (Hydro Mechanical Transmission; hereinafter,
"HMT"). This HMT uses a hydrostatic transmission that utilizes the static pressure energy of the fluid.
mission; hereinafter, referred to as “HST”) and a mechanical transmission (hereinafter, referred to as “MT”) through a planetary gear mechanism or the like, thereby performing continuous and continuous shifting.

[0002]

2. Description of the Related Art Conventionally, as this type of continuously variable transmission, US Pat. No. 4,341,131 or
One proposed in Japanese Patent Application Laid-Open No. 54-55560 is known. This is, as shown in FIG. 1, an HST (4) in which a hydraulic pump (5) having a variable swash plate (51) and a hydraulic motor (6) having a fixed swash plate (61) are connected to each other; First and second two planetary gear mechanisms (7, 8) and first to third three clutch mechanisms (10, 11, 12) for switching operating conditions of the respective planetary gear mechanisms (7, 8). ) Etc. are combined with MT (3). And the continuously variable transmission proposed above is
The relationship between the gear ratios of the two planetary gear mechanisms (7, 8) is set to specific conditions, and the variable swash plate (5) is used at the time of each mode switching when operating in three operation modes.
The shift control is performed under the condition that 1) has the same swash plate angle (maximum swash plate angle) as that of the fixed swash plate (61).

[0003] Usually, in the HMT of the above-mentioned patent publication,
As shown in FIG. 2, the variable swash plate (51) of the hydraulic pump (5) of the HST (4) is set at 3 according to the gear ratio of the HMT.
The rotation is controlled separately in two operation modes, whereby the rotation at a constant rotational speed input from the drive source such as the engine to the input shaft (1) of the HMT is controlled with respect to the output shaft (2) of the HMT. The system is designed to be transmitted steplessly and continuously changing. That is, in each of the three operation modes of the first mode, the second mode, and the third mode, by controlling the displacement of the hydraulic pump (5) and the hydraulic motor (6) of the HST (4), the gear ratio of the HMT is reduced. It is controlled to change steplessly and continuously.
In this case, in each of the operation modes, the variable swash plate (51) of the hydraulic pump (5) changes the maximum swash plate angle (for example, +17) according to the HMT gear ratio as shown by a two-dot chain line in FIG.
The swash plate of the hydraulic motor (6) is controlled so that the swash plate angle is gradually increased and decreased at a constant increase / decrease change ratio between the neutral position (zero swash plate angle) and the neutral position (zero swash plate angle). The fixed swash plate (61) is set so that the swash plate angle always becomes the above-mentioned maximum swash plate angle as shown by a dashed line in FIG. Then, the variable swash plate (51) has the maximum swash plate angle on the normal rotation side or the reversal side, and its absolute value has the same swash plate angle as the fixed swash plate (61). At the speed ratio corresponding to the number of revolutions
Switching from the first mode to the second mode and switching from the second mode to the third mode are performed.

On the other hand, on the MT (3) side, only the first clutch mechanism (10) is connected in the first mode, and only the second clutch mechanism (11) is connected in the second mode. And the third clutch mechanism (12) in the third mode.
Only each of the clutch mechanisms (10, 11, 12) is switched when each mode is switched. When the clutch mechanisms (10, 11, 12) are switched on and off, the first and second planetary gear mechanisms are tuned at the same rotational speed and transmitted at a continuous gear ratio before and after the switching. (7,
Condition 8) is set so that each gear ratio has the following specific relationship. That is, the ratio of the number of teeth between the sun gear (71) of the first planetary gear mechanism (7) and the internal gear (73) is Y, and the ratio of the sun gear (81) of the second planetary gear mechanism (8) is When the ratio of the number of teeth with respect to the internal gear (83) is X, the condition is established so that the relationship of Y = X + 1 is satisfied (see FIG. 3).

[0005]

By the way, even when a vehicle equipped with the above-mentioned conventional continuously variable transmission maintains a constant speed, the power is transmitted via both the MT (3) and the HST (4). Since it is not preferable in terms of transmission efficiency to continue the normal operation for performing transmission, in such a case, for example, as shown in FIG. 4, the swash plate angle is changed by changing the swash plate angle of the swash plate (61 '). A lock-up operation mechanism such as a mechanism (14), a bypass mechanism (15 '), and a rotation fixing mechanism (16) is provided.
The lock-up operation is performed by interrupting the power transmission via ST (4) and switching the power transmission from input shaft (1) to output shaft (2) via only MT (3). It is possible to do.

For example, the variable swash plate (5) of the hydraulic pump (5)
1) a mode switching point at which the absolute value is the same as the maximum swash plate angle with the swash plate (61 ') of the hydraulic motor (6), and the speed ratio position of the maximum speed ratio (the position indicated by the rotation speed, in FIG. 2); The intermediate speed ratio position (the position indicated by the rotation speed in FIG. 2) of each mode in which the variable swash plate (51) is at the neutral position where the swash plate angle is zero is defined as a lock-up operation point. When the vehicle is in a predetermined constant-speed running state, it is conceivable to switch the operating state from the normal operation to the lock-up operation as follows.

That is, in the lock-up operation at the gear ratio position (rotation speed) of the mode switching, when the rotation speed is reached, the first clutch mechanism (10) and the second clutch mechanism (11) are connected. In the case of rotation speed, two clutch mechanisms (11) and third clutch mechanism (1) are used.
2) and the double clutch operation is performed by connecting the two. Thereby, both swash plates (51,
61 ′) are at the same angle (maximum swash plate angle) at the time of mode switching, so that both the hydraulic pump (5) and the hydraulic motor (6) are idling, and the output shaft (2) is moved from the input shaft (1) to the output shaft (2). ) Will only be transmitted via MT (3). In the lock-up operation at the intermediate speed ratio position (rotation speed) in the above mode, the variable swash plate (51) is brought to the neutral position at zero swash plate angle by the normal operation at the time of switching to the lock-up operation. Since the pump shaft (52) is positioned, the pump shaft (52) is brought into a stopped state in which the pump shaft (52) only idles and the motor shaft (62) does not rotate.
6) Open the solenoid on-off valve (163) and open the engagement piece (1).
62) is engaged with the gear (66) to fix the motor shaft (62) in a non-rotating state. As a result, rotation and torque transmission from the input shaft (1) to the output shaft (2) are performed only via the MT (3). Further, in the lock-up operation at the maximum speed ratio position (rotation speed), the actuator (1) of the bypass mechanism (15 ') is operated.
53) to extend the gears (151, 152) on the input / output end side of the bypass shaft (150) to the gears (56, 76).
To make the connection state. Thereby, HST
Since both swash plates (51, 61 ') of (4) are at the same angle (maximum swash plate angle) with each other, both the hydraulic pump (5) and the hydraulic motor (6) run idle, and the input shaft (1) ) To the output shaft (2) is transmitted only through the MT (3).

In the lock-up operation of the number of revolutions, by controlling both the swash plates (51, 61 ') to the neutral position, the reciprocating motion of the pistons (54a, 64a) and the circulation of the hydraulic oil are also reduced. It is also possible to further reduce the loss by eliminating it. In this case, the variable swash plate (51) of the hydraulic pump (5) is returned to the neutral position, and then the actuator (142) of the swash plate angle switching mechanism (14) is reduced to operate by the restoring pressing force of the pressing spring (143). Swash plate (61 ')
Is switched to the neutral position where the swash plate angle is zero.

[0009] However, the HM by the inventor of the present application.
As a result of a study focused on improving the transmission efficiency of the entire T, even if the lock-up operation as described above was performed,
It has been found that the following inconvenience occurs in the lock-up operation.

That is, when the lock-up operation is switched at each of the lock-up operation points at the mode switching point (rotation speed) and the maximum gear ratio position (rotation speed), the hydraulic motor (6) enters an idle state, and When the mode is switched to the lock-up operation at each lock-up operation point at the mode intermediate position (rotation speed), the hydraulic motor (6)
Is fixed. However, regardless of whether the hydraulic motor (6) is in the idling state or in the fixed state, during the lock-up operation at all the lock-up operation points,
Since the hydraulic pump (5) keeps idling while sliding with respect to the center section (41) of the HST (4), no-load loss occurs due to the idling of the hydraulic pump (5). In addition, in this case, the hydraulic motor (6) also keeps idling while sliding with respect to the center section (41) at the mode switching point or the like (rotation speed,). The no-load loss due to the sliding loss further occurs.

Therefore, especially in the lock-up operation at the above-mentioned mode switching point or the like (rotation speed,), even if an attempt is made to improve the transmission efficiency of the entire HMT by executing the lock-up operation, only the amount of the no-load loss is generated. The improvement of the transmission efficiency is hindered, and there is a disadvantage that the transmission efficiency of the entire HMT is not so good.

The present invention has been made in view of such circumstances, and a purpose thereof is to realize a lock-up operation capable of improving transmission efficiency of the entire HMT as much as possible. .

[0013]

In order to achieve the above object, the invention according to claim 1 is based on the following continuously variable transmission. That is, the input shaft (1) connected to the power source
, An output shaft (2), the input shaft (1) and an output shaft (2)
A mechanical transmission (3) interposed between the input shaft (1) and the output shaft (2) including a plurality of clutch mechanisms (10 to 12) and a plurality of planetary gear mechanisms (7, 8); And the input side is the input shaft (1)
And a hydrostatic transmission (4) whose output side is connected to the output shaft (2) via the mechanical transmission (3). Further, the hydrostatic transmission (4)
An input-side hydraulic pump (5) that converts a rotational force input from the input shaft (1) to the pump shaft (52) into a predetermined discharge pressure liquid by controlling a change in a swash plate angle of the variable swash plate (51).
And a hydraulic motor (6) on the output side for converting a hydraulic pressure discharged from the hydraulic pump (5) into rotational force by a swash plate (61) in a predetermined inclined state to rotate a motor shaft (62). It is assumed that one has In addition, the input is input to the input shaft (1) by operating the mechanical transmission (3) and the hydrostatic transmission (4) in a plurality of operation modes according to the gear ratio in normal operation. The output shaft (2) by continuously changing the input rotation
The transmission is assumed to be continuously variable.

In this case, the invention according to claim 1 is a first motor for connecting the motor shaft (62) of the hydrostatic transmission (4) to the mechanical transmission (3) in an intermittent manner. When the rotational speed of the clutch mechanism (17) and the output shaft (2) is at a specific rotational speed, the input shaft (1) is changed from the normal operation state.
A lock-up switching control means (19) for switching control to a lock-up operation in which power is transmitted to the output shaft (2) only through the mechanical transmission (3); Lock-up release control means (19) for switching control to return to operation
And a configuration including: A first motor clutch disconnection control unit for switching the first motor clutch mechanism (17) from a connected state to a disconnected state as the lockup switching control means (19); and a variable swash plate of the hydraulic pump (5). If the swash plate angle in (51) is not zero, a swash plate angle change control unit that changes the swash plate angle to zero in accordance with the switching control by the first motor clutch cutoff control unit is provided. In addition, the lock-up release control means (1)
9) a swash plate angle return control unit that returns the swash plate angle of the variable swash plate (51) changed by the swash plate angle change control unit to the swash plate angle at the time of switching to the lock-up operation; The variable swash plate (5
And a first motor clutch connection control unit that switches the first motor clutch mechanism (17) from the disconnected state to the connected state when the swash plate angle of (1) is restored.

In the case of the above configuration, during normal operation, M
T (3) multiple clutch mechanisms (10-12) and HST
The swash plate angle of the variable swash plate (51) in (4) is operated in a plurality of operation modes according to the gear ratio, whereby the input rotation at a constant rotation speed input from the input shaft (1) is stepless. And transmitted to the output shaft (2).

On the other hand, at a gear ratio such that the rotation speed of the output shaft (2) becomes a specific rotation speed, after the double clutch, the motor clutch mechanism cut-off control unit of the lock-up switching control means (19) operates. The motor clutch mechanism (17) is switched to the disconnected state. Thereby, H
The motor shaft (62) which is the output side of ST (4) and MT
(3) is separated from the motor shaft (62) to MT
While the power transmission to (3) is completely shut off, the motor shaft (62) can freely idle. Therefore, even if the hydraulic oil is discharged from the hydraulic pump (5) to the hydraulic motor (6) even when the variable swash plate (51) is in a state other than the neutral position at the swash plate angle of zero, the discharge oil amount Will spin at just enough rotation speed. If the variable swash plate (51) is in a state other than the neutral position while the motor clutch mechanism (17) is switched to the disengaged state, the swash plate angle of the lock-up switching control means (19) is changed. Since the variable swash plate (51) is changed to the neutral position by the change control unit, the discharge of the hydraulic oil to the hydraulic motor (6) is stopped. As a result, the idling of the motor shaft (62) is also stopped. This eliminates the no-load loss on the hydraulic motor (6) side during the lock-up operation period. Thereby, especially when the lockup operation is switched at the gear ratio corresponding to the switching speed of the operation mode, the transmission efficiency of the entire HMT during the lockup operation period is improved.

When the lock-up operation is released to return to the normal operation, the swash plate angle of the variable swash plate (51) is controlled by the swash plate angle return control unit of the lock-up release control means (19). Thus, the number of rotations of the motor shaft (62) and the MT (3) in the state where the motor clutch mechanism (17) is connected at the specific rotation speed of the output shaft (2) before the lock-up operation switching is performed. That is,
The motor shaft (62) is converted into a state in which the motor shaft (62) idles at the meshing rotation speed with the gear (76) on the MT (3) side. Then, in this state, the lock-up release control means (19)
Since the motor clutch connection control unit switches the motor clutch mechanism (17) to the connected state, it is possible to return to the normal operation without switching shock. Therefore, even if the control during the lock-up operation period is performed as described above to improve the transmission efficiency, it is possible to smoothly return from the control state during the lock-up operation to the normal operation.

According to a second aspect of the present invention, in the first aspect of the present invention, the fixed state in which the motor shaft (62) of the hydrostatic transmission (4) is pressed against the non-rotating portion (103), and A configuration is provided with a second motor clutch mechanism (18) for switching between a free rotation state separated from (103) and a free rotation state. In addition, the lock-up switching control means (19) switches the second motor clutch mechanism (18) in a state where the normal operation is switched to the lock-up operation and the rotation of the motor shaft is stopped.
A lock-up release control means (1) for switching a second motor clutch from a free rotation state to a fixed state.
9) As a configuration having a second motor clutch release control unit that switches the second motor clutch mechanism (19) from a fixed state to a free rotation state when the variable swash plate (51) is at a swash plate angle of zero. It is.

In the above configuration, when the swash plate angle is changed to the neutral position and the idling of the motor shaft (62) is stopped, the swash plate angle change control unit locks the normal swash plate from the normal operation. The second motor clutch mechanism (18) is switched to the lock-up operation switching control means (19).
Is fixed by the second motor clutch fixing control unit. As a result, the motor shaft (62) is fixed in a non-rotating state, and an increase in hydraulic pressure inside the hydraulic motor (6) is prevented, so that sliding resistance is minimized. This allows
The occurrence of no-load loss during the lock-up operation period is more reliably prevented, and the transmission efficiency of the entire HMT is more reliably improved. In addition, even when returning from the lock-up operation to the normal operation, the second motor clutch mechanism (18) uses the lock-up operation release control means (1).
Since the variable swash plate (51) is switched from the fixed state to the free rotation state in a state where the variable swash plate (51) is in the neutral position by the second motor clutch release control unit of 9), the above-described return to the normal operation is performed without any trouble.

According to a third aspect of the present invention, in the first or second aspect, the hydrostatic transmission (4) is disposed in parallel with the input shaft (1) and the output shaft (2). ) Input side gear connection mechanism (56, 11)
4) and a bypass mechanism for transmitting rotational power by intermittently switching between a connection end (75) of the mechanical transmission (3) and an output side of the hydrostatic transmission (4). 15).
In addition, as the lock-up switching control means (19), the bypass mechanism (1) is provided at the highest gear ratio position in normal operation.
5) a bypass operation control unit for switching to the connection state;
As the lock-up release control means (19), the bypass mechanism (15) is synchronized with control for returning the rotational power from the motor shaft (62) of the hydraulic motor (6) to the mechanical transmission (3). ) Is provided with a bypass release control unit that switches to a cutoff state.

In the above configuration, the bypass mechanism (15) is switched to the connected state by the bypass operation control unit, so that the rotational power input from the input shaft (1) from the hydrostatic transmission (4) in the normal operation is obtained. Is transmitted to the connection end (75) of the mechanical transmission (3) via the bypass mechanism (15), and the hydrostatic transmission (4) is bypassed. Therefore, for example, even when the normal operation is performed in three operation modes, the normal operation and the lock-up operation are controlled by the bypass operation control unit and the bypass release control unit at the maximum speed ratio position in the third mode. It is possible to switch the operating state between the two.

Further, the invention described in claim 4 is the first invention.
In the described invention, the variable swash plate (5) of the hydraulic motor (5) is used.
Normal operation control means for controlling the increase / decrease change of the swash plate angle in at least three operation modes in 1) is provided. In the normal mode operation control means, in the first mode in the low speed ratio range from the start, the swash plate angle becomes the neutral position at the minimum value of the speed ratio range of the first mode, and the tilt direction (−) at the maximum value. ), The swash plate angle of the variable swash plate (51) is changed at an increase / decrease change ratio such that the swash plate angle becomes the maximum swash plate angle, and the second mode of the second mode in a speed ratio range higher than the first mode is changed. The above-mentioned variable is changed by the increase / decrease change ratio such that the minimum value of the speed ratio range becomes the maximum swash plate angle on the (-) side, the intermediate value becomes the neutral position and the maximum value becomes the maximum swash plate angle on the tilt direction (+) side. Swash plate (51) The swash plate angle is changed, and the third swash plate angle is changed in a third mode having a higher speed ratio range than the second mode.
The maximum swash plate angle in the tilt direction (+) at the minimum value of the gear ratio range of the mode, the neutral position at the intermediate value, and the maximum swash plate angle in the tilt direction (-) at the maximum value. The variable swash plate (51) is configured to change the swash plate angle at an increase / decrease change ratio. Also, the swash plate (61) of the hydraulic motor (6)
Is fixed to the swash plate angle which is equal in absolute value to both the maximum swash plate angles. The lock-up switching control means includes a switching speed corresponding to a switching speed ratio between the first mode and the second mode, and an intermediate speed corresponding to an intermediate value in a speed ratio range of the second mode. A switching speed corresponding to a switching speed ratio between the second mode and the third mode, an intermediate speed corresponding to an intermediate value in a speed ratio range of the third mode, and a maximum speed in the third mode. Switching from normal operation to lock-up operation is performed with the rotation speed corresponding to the ratio as the specific rotation speed.

In the case of the above-described configuration, the contents of the control for increasing or decreasing the swash plate angle of the variable swash plate (51) of the hydrostatic transmission (4) when the normal operation is performed in three operation modes are specifically described. Specified. In addition, when the normal operation is performed, the switching operation point to the lock-up operation includes two switching speeds of the first mode and the second mode, the second mode and the third mode, and the second switching speed. And five intermediate rotation speeds of the third mode and a rotation speed corresponding to the highest speed ratio of the third mode.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 shows an HMT which is a continuously variable transmission according to an embodiment of the present invention. In FIG. 5, reference numeral 1 denotes a fixed number of rotations from the engine connected to an engine (not shown) as a power source. Are input shafts (1), 2 are output shafts connected to driving wheels (not shown) via a final reduction gear (not shown), and 3 are the input shaft (1) and the output shaft (2). MT as a mechanical transmission interposed between the two. Reference numeral 4 designates an input side connected to the input shaft (1) and an output side connected to the MT (3) in parallel with the MT (3).
An HST as a hydrostatic transmission connected to the output shaft (2) via (3),
T (4) is a hydraulic pump (5) on the input side having a variable swash plate (51) and a swash plate (6) fixed at a predetermined maximum swash plate angle.
And an output-side hydraulic motor (6) having 1). Further, 15 is a bypass mechanism, and 17 and 18 are first and second motor shafts (62) of the hydraulic motor (6).
The second motor clutch mechanism 19 is a control unit including a normal operation control unit, a lock-up switching control unit, a lock-up release control unit, and the like.

-Configuration of MT-The MT (3) is arranged coaxially with the first planetary gear mechanism (7), the second planetary gear mechanism (8), the input shaft (1) and the output shaft (2). Provided intermediate shaft (9) and first to third three clutch mechanisms (10, 1).
1, 12). Hereinafter, each mechanism (7,
8, 10, 11, 12) will be described in detail.

The first planetary gear mechanism (7) includes a first sun gear (71), a first planetary gear (72) meshing with the first sun gear (71), and a first planetary gear (72). And a first carrier (74) for holding the first planetary gear (72). The second planetary gear mechanism (8) includes a second sun gear (81) formed on the intermediate shaft (9) and the second sun gear (81).
A second planetary gear (82) meshing with the sun gear (81);
The first internal gear (8) meshing with the second planetary gear (82)
3) and a second carrier (84) for holding the second planetary gear (82).

The first sun gear (71) is formed integrally with the gear (76) via an annular connection shaft (75) externally rotatable relative to the output shaft (2). The gear (76) is connected to the hydraulic motor (6) via a gear (66) described later. The first carrier (74) is attached to a tubular member (77), and the inner surface of the tubular member (77) has the second carrier (74).
An internal gear (83) is formed, whereby the first carrier (74) and the second internal gear (83) rotate in synchronization with each other. Further, the first internal gear (73) is formed on the outer peripheral side of the collar member (78), and the second carrier (84) is attached to the collar member (78). The collar member (78) is integrally attached to the output shaft (2), whereby the second carrier (84) rotates in synchronization with the first internal gear (73), In addition, the first internal gear (73) and the second carrier (84) are coupled to the output shaft (2).

The first clutch mechanism (10) includes a plurality of clutch plates (101) and a plurality of pressure plates (102) sandwiching each of the clutch plates (101). Each pressure plate (102) is fixed to a non-rotating portion (103), which is a casing (not shown) of the present HMT, in a state in which relative rotation is prevented.
0) is to apply a braking force by setting the connection state. Each of the above clutch plates (101)
Is mounted around the tubular member (77), whereby the first clutch mechanism (10) connects the first carrier (74) and the second internal gear (83) to the non-rotating portion ( 103) so as to be intermittently switchable.

The second clutch mechanism (11) includes a plurality of clutch plates (111) attached around the outer periphery of the intermediate shaft (9) and a pressure plate provided on the inner peripheral surface of the cylindrical member (112). (113). The cylindrical member (112) is connected to the input shaft (1) via a gear (114), whereby the second clutch mechanism (11) connects the second sun gear (81) to the input shaft (1). 1) is connected so as to be capable of intermittent switching.

The third clutch mechanism (12) is provided on a plurality of clutch plates (121) attached to the outer periphery of the tubular member (77) and on the inner peripheral surface of the tubular member (112). And a pressure plate (122), whereby the first carrier (7
4) and the second internal gear (83) are connected to the input shaft (1) in an intermittent manner.

In such a structure, the ratio of the number of teeth of each element of the first and second planetary gear mechanisms (7, 8) is set so as to have the following relationship. A substantially continuous transmission ratio is provided before and after switching between the three operation modes of the first to third modes. That is, as shown in the planetary velocity diagram of FIG. 3, the gear ratio between the first sun gear (71) and the first internal gear (73) is Y.
When the ratio of the number of teeth between the second sun gear (81) and the second internal gear (83) is X, the relationship of Y = X + 1 is established. (Thus, before and after switching between both the first mode (M1) and the second mode (M2), the rotation speed of the second sun gear (81) is engaged by the second clutch mechanism (11). The same as the tuning speed N1 of the input shaft (1) (for example, 1800 rpm),
The rotation speed of the carrier (74) before and after switching between the two operation modes of the second mode (M2) and the third mode (M3) is the third.
This coincides with the above-mentioned tuning speed N1 of the input shaft (1) engaged by the clutch mechanism (12). -HST configuration-On the other hand, the HST (4) is composed of a pair of hydraulic units having substantially the same configuration and a center section (41) connecting the two hydraulic units, and the rotational force from the engine is reduced. The input-side hydraulic unit to be input is called a hydraulic pump (5), and the output-side hydraulic unit that outputs the rotational force after shifting is called a hydraulic motor (6).

As shown in FIG. 6, the hydraulic pump (5) has a cylinder block (53) which rotates integrally with a pump shaft (52) via a spline, and a circle in the cylinder block (53). A plurality of reciprocating pistons (54, 54,...) Housed in a row in the circumferential direction, and a variable swash plate (51) for adjusting a reciprocating stroke of the plurality of reciprocating pistons (54, 54,...). The cylinder block (53) is liquid-tightly connected to the non-rotating center section (41). Then, the pump shaft (5)
The gear (56) connected to 2) is meshed with the gear (114) of the input shaft (1), whereby the pump shaft (52) also receives the torque from the engine via the input shaft (1). Is to be entered.

The center section (41)
A non-rotating block (55) on the hydraulic pump (5) side, a non-rotating block (65) on the hydraulic motor (6) side, and a pair of communication passages connecting between the non-rotating blocks (55, 65). 5
7a, 57b). Inside the non-rotating block (55), two arc-shaped openings (55a, 55b) (55a, 55b) that can communicate with the cylinder chambers (54a) of the plurality of reciprocating pistons (54, 54, ...). A
Kidney and B-kidney; see FIG. 7), and this A-kidney (55a) or B-kidney (55b)
Is a non-rotating block (6) on the hydraulic motor (6) side described later.
5) The corresponding communication paths (57a, 57b) with the corresponding A-kidney (65a) or B-kidney (65b), respectively.
Are communicated through.

Further, the variable swash plate (51) has a maximum swash plate across a neutral position (N) where the swash plate angle becomes zero, with a diameter crossing the position of the pump shaft (52) as a rotation shaft (P). The actuator (20; FIG. 5) moves between the maximum inclination angle positions (M, M ') at which the plate angle (for example, 17 degrees in absolute value) is obtained.
), And the angle of the swash plate of the variable swash plate (51) is controlled by the control unit (19).
The control unit (19) is configured to continuously increase or decrease at a predetermined increase or decrease change ratio according to the first to third operation modes by the normal operation control means.
The swash plate angle of the variable swash plate (51) is controlled by receiving control signals from the swash plate angle change control unit of the lock-up switching control unit and the swash plate angle return control unit of the lock-up release control unit. It has become.

The hydraulic motor (6) includes a cylinder block (63) that rotates integrally with the motor shaft (62) via a spline, and a circumferentially arranged line in the cylinder block (63). The plurality of reciprocating pistons (64, 64,...) Housed therein and the plurality of reciprocating pistons (6
, Swash plate (61) for adjusting the reciprocating stroke of the cylinder block (6, 64,...).
3) is liquid-tightly connected to the non-rotating block (65) of the center section (41). Inside the non-rotating block (65), like the other non-rotating block (55), the plurality of reciprocating pistons (64,
64,...) Are formed with an A-kidney (65a) and a B-kidney (65b) (see FIG. 7) which can communicate with the cylinder chambers (64a).

The gear (66) at the output end of the motor shaft (62) is meshed with a gear (76) coupled to a connecting shaft (75) integral with the first sun gear (71),
The pair of gear mechanisms (66, 76) serve as a motor shaft (62).
And MT (3). The motor shaft (62) has a motor shaft (62) and a gear (66).
A first motor clutch mechanism (17) interposed between the motor shaft (62) and the gear (66) for intermittently switching the rotational power of the motor shaft (62); The motor shaft (62) is interposed between the motor shaft (62) and the non-rotating portion (103) to switch the motor shaft (62) between a fixed state and a free rotation state so as to be mutually convertible. Second motor clutch mechanism (1
8) are interposed. In normal operation, the first motor clutch mechanism (17) is maintained in the connected state, and the second motor clutch mechanism (18) is maintained in the free rotation state, whereby the rotational power from the motor shaft (62) is transmitted to the gear mechanism. (66, 76) and the connection shaft (75) are transmitted to the first sun gear (71). on the other hand,
The first and second motor clutch mechanisms (17, 1
8) In the lock-up operation, the first motor clutch disconnection control section and the second motor clutch fixing control section of the lock-up operation switching control means of the control unit (19), and the first motor clutch of the lock-up release control means. The operation is controlled by the connection control unit and the second motor clutch release control unit.

Here, the operation principle of the HST (4) will be briefly described. The rotation from the engine is transmitted to the pump shaft (52) via the input shaft (1), the gear (114) and the gear (56). However, when the variable swash plate (51) is located at the neutral position N, each piston (54) does not stroke, so that the hydraulic oil in each cylinder (54a) is supplied to the hydraulic motor (6) side. Without being discharged, the cylinder block (53) becomes idle. However, when the variable swash plate (51) is tilted toward the maximum tilt position M, each piston (54) strokes according to the angle of the swash plate, and pressure oil of a discharge amount corresponding to this stroke is supplied to one of the communication passages ( The fluid is discharged to each cylinder chamber (64a) of the hydraulic motor (6) through 57a or 57b). When each piston (64) of the hydraulic motor (6) receiving this amount of pressure oil presses the inclined swash plate (61), the cylinder block (63) and motor shaft (62) discharge the oil. It is rotated at the rotation speed according to the amount. Then, the fluid is returned from the cylinder block (63) to the hydraulic pump (5) through the other communication path (57b or 57a). At this time, if the variable swash plate (51) has the swash plate angle on the (+) side maximum inclination position M side, the cylinder block (6) of the hydraulic motor (6)
3) rotates forward in the same direction as the input rotation, and conversely, if the variable swash plate (51) is at the swash plate angle on the (−) side maximum tilt position M ′ side, the cylinder block (63) is The input rotation is reversed in the opposite direction.

-Configuration of Bypass Mechanism- The bypass mechanism (15) is disposed between the MT (3) and the HST (4) so as to extend in parallel with the input shaft (1) and the output shaft (2). The vehicle includes a bypass shaft (155) and a bypass clutch mechanism (156) interposed between the bypass shaft (155) and intermittently switching transmission of rotational power via the bypass shaft (155). The input end gear (157) of the bypass shaft (155) is always engaged with the gear (56) of the pump shaft (52) while the output end gear (158) is connected to the connection shaft (158). 7
5) is always engaged with the gear (76). Further, the bypass clutch mechanism (156)
Is normally shut off in a normal operation state, and is connected at a specific lock-up operation point by a bypass operation control unit of lock-up switching control means in the control unit (19). .

-Operation of MT and HST in normal operation-MT (3) and HST (4) are divided into three operation modes classified according to the speed ratio, that is, from the start to the low speed ratio range (low speed range). A first mode, a second mode in a middle speed ratio range (middle speed range), and a third mode in a high speed ratio range (high speed range).
Control unit (19) divided into two operation modes
The operation is controlled by the normal operation control means. The normal operation control means controls the operation of the first to third clutch mechanisms (10 to 12) and the increase / decrease change control of the swash plate angle of the variable swash plate (51) by the operation control of the actuator (20). Each is performed based on the gear ratio. In this normal operation, the bypass clutch mechanism (156) is maintained in the disconnected state, the first motor clutch mechanism (17) is maintained in the connected state, and the second clutch mechanism (18) is maintained in the free rotation state.

First, the intermittent switching control of each clutch mechanism (10 to 12) in each operation mode in the MT (3) will be described.

In the first mode, only the first clutch mechanism (10) is brought into the connected state, whereby the rotation input from the input shaft (1) is transmitted to the HST (4) only from the input shaft rotation speed Ni. Thus, the output shaft (2) is rotated only by the transmission force from the HST (4). On the other hand, M
At T (3), the second and third clutch mechanisms (1
Since the tubular member (112) is in the shut-off state, the cylindrical member (112) is brought into the idling operation state, and the first carrier (74).
Is connected to the non-rotating portion (103) by the first clutch mechanism (10) and is fixed in a non-rotating state.

Further, in the second mode, only the second clutch mechanism (11) is in the connected state, whereby the rotation input from the input shaft (1) is smaller than the HST (4) by the input shaft rotation speed Ni. On the other hand, the input shaft rotation speed Ni is transmitted to the intermediate shaft (9) via the second clutch mechanism (11). The output shaft (2) is connected to the second planetary gear mechanism (8).
, And a transmission force from the intermediate shaft (9) via the first planetary gear mechanism (7) and a transmission force from the HST (4) via the first planetary gear mechanism (7).

Further, in the third mode, only the third clutch mechanism (11) is brought into the connected state, whereby the rotation input from the input shaft (1) is smaller than the HST (4) by the input shaft rotation speed Ni. On the other hand, the input shaft rotation speed Ni is transmitted to the tubular member (77) via the third clutch mechanism (12). The output shaft (2) is connected to the tubular member (7) via the first carrier (74) of the first planetary gear mechanism (7).
7) and H through the first sun gear (71).
It is rotated by a combined force with the transmission force from ST (4).

On the other hand, the operation control of the variable swash plate (51) of the hydraulic pump (5) in the HST (4) will be described.
In the first mode, the swash plate angle of the variable swash plate (51) is
The first switching speed ratio that is gradually tilted as the vehicle shifts from the neutral position at start (zero swash plate angle) to the high speed ratio side and corresponds to the first switching speed (the output shaft speed) with the second mode. At the rate of change of change such that the maximum inclination is -17 degrees
It is continuously tilted to the (-) side in accordance with the increase in the MT speed ratio (see FIG. 2).

In the second mode, the swash plate angle (-
From 17 degrees), it is continuously tilted to the (+) side at the same increase / decrease change ratio as the first mode in absolute value, and the variable swash plate (51) is neutral at the center speed ratio (intermediate rotation speed) in the second mode. Position, and after that, it is similarly tilted, and the swash plate angle reaches +17 degrees at the second switching speed ratio corresponding to the switching rotation speed with the third mode.

Further, in the third mode, switching is performed at the second switching speed ratio so as to tilt to the (-) side at the same increase / decrease change ratio as the above-mentioned increase / decrease change ratio. ), The variable swash plate (51) returns to the neutral position and is similarly tilted past it to engage the bypass clutch mechanism (156) at the highest gear ratio corresponding to the rotational speed at which the swash plate angle (51) is engaged. Reaches -17 degrees.

The control unit (19) as described above
The on / off switching control of the first to third clutch mechanisms (10 to 12) and the increase / decrease change control of the swash plate angle of the variable swash plate (51) in FIG. The speed change range in the second mode corresponds to the range indicated by arrow M2 in the figure, and the speed change range in the third mode corresponds to the range indicated by arrow M3 in the figure. Is continuously and continuously changed from the first mode to the third mode.

-Operation of MT and HST by Switching to Lock-up Operation-In FIG. 2 or FIG. 3, the lock-up operation is such that the rotation speed of the output shaft (2) corresponds to the switching speed ratio corresponding to the switching speed ratio between the modes. , And the maximum speed corresponding to the highest speed ratio in the third mode, and the intermediate speed corresponding to the center speed ratio in the second and third modes in which the variable swash plate (51) is positioned at the neutral position. At one specific rotation speed, that is, at five lock-up operation points, the lock-up switching control means in the control unit (19) controls the switching from the normal operation to the lock-up operation. Note that the determination of switching from the normal operation to the lock-up operation is performed when the rotation speed of the output shaft (2) is at any one of the above-described specific rotation speeds and the accelerator fluctuation amount (change ratio of the depression amount) is set to a predetermined value. Must be a small value within the value,
Alternatively, it is determined that the lock-up operation is performed by satisfying a condition such that the rate of change of the vehicle speed is a small value within a predetermined set value. Then, after the switching to the lock-up operation, if each of the conditions in the lock-up switching determination is not satisfied, a lock-up release command is issued and the lock-up release control means releases the lock-up operation and returns to the normal operation. Is returned.

If the lock-up switching control means satisfies the condition for determining the switching to the lock-up operation at the rotation speed, the lock-up switching command is received by the first motor clutch disconnection control unit as shown in FIG. (1) The motor clutch mechanism (17) is switched from the connected state (engaged) to the disconnected state (disengaged). Thereby, the motor shaft (62)
And the gear (66) are separated from each other,
The rotation transmission from (4) to the gear (76) of the MT (3) is cut off, and the motor shaft (62) is brought into a state in which it can freely idle.

At this time, at each lock-up operating point,
The operation of each clutch mechanism (10 to 12) is controlled as follows. That is, in the lockup operation at the switching speed, the first clutch mechanism (10) and the second clutch mechanism (11) before and after the switching between the first mode and the second mode are maintained in the double clutch operating state, In the lockup operation, the second clutch mechanism (11) and the third clutch mechanism (12) before and after switching between the second mode and the third mode are maintained in the double clutch operating state. On the other hand, at the lock-up operation point at the maximum rotation speed (), the bypass operation control unit connects the bypass clutch mechanism (156) to the input shaft (1) via the bypass shaft (155) to output the shaft (2). ). Thereby, the transmission of the rotational power from the input shaft (1) to the output shaft (2) is performed only by the MT (3) or the MT (3).
(3) and via only the bypass shaft (155).

In particular, in the lock-up operation in which the hydraulic motor (6) is idled to cancel the transmission of the rotational power as in the lock-up operation points of the switching speed (,) and the maximum speed (). In addition to the switching of the first motor clutch mechanism (17) to the disengaged state, the swash plate angle control unit controls the operation of the actuator (20) to increase the swash plate angle of the variable swash plate (51) to the maximum swash plate. The angle is changed from the angle to the neutral position where the swash plate angle is zero (see FIG. 8). As a result, in the hydraulic pump (5), the pump shaft (52) and the cylinder block (53) only idle and do not discharge hydraulic oil to the hydraulic motor (6).
The idling of the cylinder block (63) of the hydraulic motor (6) and the motor shaft (62) is stopped. Therefore, the sliding loss between the cylinder block (63) and the center section (41) is eliminated, and the no-load loss during the lock-up operation is eliminated. As a result, the transmission efficiency of the entire HMT is improved accordingly (for example, 5%). % Improvement).

In addition, the above-mentioned switching speeds (eg,
Since the idling of the hydraulic motor (6) is stopped in the lock-up operation in (1), the input speed input from the engine via the input shaft (1) becomes excessive, particularly in the highest speed range. Also hydraulic motor (6)
When the motor is kept idling, it is possible to reliably avoid the possibility that the piston (64) of the hydraulic motor (6) is damaged due to approaching the allowable rotation speed limit of the hydraulic motor (6). In the prior art, it is necessary to provide a switching mechanism for switching the swash plate angle of the swash plate (61) to the neutral position in order to increase the allowable rotation speed for the hydraulic motor (6) against such excessive input rotation. Although there are some cases, in the present embodiment, by maintaining the hydraulic motor (6) in the idling state as described above, compared with the case where such a switching mechanism is provided, the cost can be reduced and the design limit can be reduced. Optimum design can be achieved.

On the other hand, at the intermediate rotation speed of each mode, since the swash plate angle of the variable swash plate (51) of the hydraulic pump (5) is neutral, the hydraulic motor (6) is not rotated but fixed. In this state, the HST (4) does not transmit power, so that the lock-up operation is performed without any operation. However, in this state, since the HST (4) supports the rotational force from the output shaft (2), the HST (4)
The internal oil pressure rises and the cylinder block (53, 63)
The friction loss between the shaft and the center section (41) increases. In order to prevent this and further improve the transmission efficiency of the entire HMT, the second motor clutch fixing control unit switches the second motor clutch mechanism (18) from the free rotation state to the fixed state. Is preferred. In this case, the first motor clutch mechanism (17) is held in the engaged state, and the rotational force from the MT (3) is applied to the gears (76, 6).
6) and first and second motor clutch mechanisms (17, 18)
And is supported by the non-rotating part (103).

-Return from lock-up operation to normal operation-Control by the lock-up release control means receives a lock-up release command in the case of lock-up operation at the switching speed (,) and the maximum speed (). First, the actuator (20) is controlled by the swash plate angle return control unit.
To return the swash plate angle of the variable swash plate (51) from the neutral position to the original maximum swash plate angle (see FIG. 8). As a result, the motor shaft (62) returns from a state in which idling is stopped to a state in which the motor shaft (62) rotates at a meshing rotational speed with the gear (76) on the MT (3) side when returning to the original normal operation. The motor shaft (6
In a state in which 2) is rotating, the first motor clutch mechanism (17) is switched from the disconnected state (disengagement) to the connected state (engagement) by the first motor clutch connection control unit. Then, one clutch mechanism is disengaged (disconnected) according to the operation mode in which the two clutch mechanisms that have been in the double clutch operation state return from the two clutch mechanisms. Thereby, the motor shaft (6
The gear (66) of 2) and the gear (76) on the MT (3) side are synchronized to be in a connected state without a switching shock, and return to the normal operation. That is, in a state where the discharge oil pressure on the HST (4) side is increased in advance by the load acting on the motor shaft (62) when the operation is returned to the normal operation,
Since the disengagement side clutch mechanism is set in the disconnected state, it is possible to prevent the occurrence of the switching shock when returning to the normal operation.

In the case of the lock-up operation at the intermediate rotation speed (,), the normal operation to be resumed starts from the neutral position of the variable swash plate (51) with the swash plate angle of zero. Variable swash plate (5
In the state 1), the second motor clutch release control unit switches the second motor clutch mechanism (18) from the fixed state to the free rotation state by receiving the lock-up release command.

In the case of the lock-up operation at the maximum rotation speed (), the bypass is synchronized with the switching control to the connection state by the first motor clutch connection control unit at the switching speed (,). The release control unit may switch the bypass clutch mechanism (156) to the disconnected state (disengagement). As a result, the transmission of rotational power (lock-up operation) via the bypass shaft (155) up to that point is switched to the transmission of rotational power via HST (4) and MT (3) (normal operation). become.

Therefore, in order to improve the transmission efficiency of the entire HMT, the first clutch mechanism (17) and the variable swash plate (51) are moved to the neutral position during the lock-up operation period at the above-mentioned switching speed (,,). Even if the change control is performed, when the lock-up operation is canceled and the operation is returned to the normal operation, the operation can be surely returned to the normal operation without generating the switching shock.

<Other Embodiments> The present invention is not limited to the above embodiments, but includes various other embodiments. That is, in order to eliminate the loss in the no-load operation of the HST (4) during the lock-up operation of the above-described embodiment and further improve the efficiency,
Release of the charge pressure of the charge oil for leak replenishment to the HST (4), reduction of the pressing force of each cylinder block (53, 63), and bypass between the two communication passages (57a, 57b) are performed. Is also good.

In the above embodiment, the pair of planetary gears (7, 8) and the first to third three clutch mechanisms (10 to 10) are used.
12), the normal operation is performed by dividing the operation mode into three operation modes using the MT (3), and the lock-up operation is performed when the rotation speed of the output shaft (2) is within five specific rotation speeds of However, the present invention is not limited to this, and a third planetary gear mechanism as an input rotation speed reduction mechanism for reducing the input rotation speed from the input shaft (1) to the MT side, and switching of the operation thereof is performed. The operation mode is increased to four or more modes by providing a pair of clutch mechanisms as a switching mechanism for performing the operation.
The present invention may be applied to an HMT in which the lock-up operation point is increased to seven or more lock-up operation points by providing a swash plate angle switching mechanism for the swash plate of the hydraulic motor on the ST side. In such a case, the step of switching the swash plate angle switching mechanism added to the swash plate on the hydraulic motor side to the neutral position at least with the swash plate angle of zero can be omitted, and cost reduction can be achieved. Can be planned.

[0061]

As described above, according to the continuously variable transmission according to the first aspect of the present invention, in particular, the variable swash plate (51) is provided.
The swash plate (51) is forcibly changed to the neutral position even when the lock-up operation is switched to a swash plate angle other than the neutral position at a gear ratio corresponding to the switching speed of the operation mode, for example. As a result, the discharge of the hydraulic oil to the hydraulic motor (6) is stopped, so that the idling of the motor shaft (62) is stopped, and the sliding of the hydraulic motor (6) during the lock-up operation is performed. It is possible to eliminate the occurrence of dynamic loss.
As a result, the occurrence of no-load loss during the lock-up operation period is eliminated, the transmission efficiency of the entire HMT during the lock-up operation period can be improved, and the input rotation speed during the lock-up operation period is excessively high. Even in such a case, it is possible to reliably eliminate the possibility of damaging the hydraulic motor.

Even if the control during the lock-up operation is performed as described above to improve the transmission efficiency, it is possible to smoothly and reliably return from the control state during the lock-up operation to the normal operation. it can.

According to the second aspect of the invention, in addition to the effect of the first aspect, when the rotation of the motor shaft (62) is stopped, the hydraulic pressure is controlled by the switching control of the two-motor clutch mechanism (18). Since the increase in oil pressure inside the motor (6) is prevented and the sliding resistance is minimized, it is possible to more reliably prevent the occurrence of no-load loss during the lock-up operation period, and to reduce the transmission efficiency of the entire HMT. Improvements can also be made more reliable.

According to the third aspect of the present invention, in addition to the effects of the first or second aspect of the present invention, for example, even when the normal operation is performed in three operation modes, the third mode can be used. At the maximum speed ratio position, the operation state can be switched between the normal operation and the lock-up operation under the control of the bypass operation control unit and the bypass release control unit.

According to the fourth aspect of the present invention, in addition to the effect of the first aspect of the invention, the variable swash plate of the hydrostatic transmission (4) in the case where normal operation is performed in three operation modes. Five specific rotation speeds can be specifically specified as the content of the swash plate angle increase / decrease change control in (51) and the switching operation point to the lockup operation when such normal operation is performed.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a conventional continuously variable transmission.

FIG. 2 shows the relationship between the angle of the swash plate of the variable swash plate of the hydraulic pump and the angle of the swash plate of the hydraulic motor and the HMT gear ratio, and the relationship between the rotation speed of the input shaft and the output shaft and the HMT gear ratio. It is explanatory drawing which shows and associates.

FIG. 3 is a planet speed diagram of the first and second planetary gear mechanisms of FIG. 1;

4 is a diagram corresponding to FIG. 1 of a continuously variable transmission that can be considered to solve the inconvenience of the continuously variable transmission of FIG. 1;

FIG. 5 is a diagram corresponding to FIG. 1, showing an embodiment of the present invention.

FIG. 6 is a simplified vertical sectional view showing an HST.

FIG. 7 is an explanatory cross-sectional view showing both non-rotating blocks along the line CC and the line DD in FIG. 6;

FIG. 8 is an explanatory diagram showing a change in the motor shaft rotation speed, a control of the operation of the first clutch mechanism, and a control of changing the swash plate angle of the variable swash plate when switching to the lock-up operation and returning to the normal operation. .

[Explanation of symbols]

Reference Signs List 1 input shaft 2 output shaft 3 MT (mechanical transmission) 4 HST (hydrostatic transmission) 5 hydraulic pump 6 hydraulic motor 7 first planetary gear mechanism 8 second planetary gear mechanism 10 first clutch mechanism 11 second clutch Mechanism 12 Third clutch mechanism 15 Bypass mechanism 17 First motor clutch mechanism 18 Second motor clutch mechanism 19 Control unit (normal operation control means, lock-up switching control means, lock-up release control means) 51 Variable swash plate 52 Pump shaft 61 Swash plate 62 Motor shaft

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-8-277907 (JP, A) JP-A-2-38745 (JP, A) JP-A-6-101744 (JP, A) JP-A-50- 22167 (JP, A) JP-A-64-87945 (JP, A) JP-A-9-159007 (JP, A) JP-A-61-59059 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 47/02-47/04

Claims (4)

(57) [Claims] An input shaft (1) connected to a power source, an output shaft (2), and a plurality of clutch mechanisms (10) interposed between the input shaft (1) and the output shaft (2). 12) and a mechanical transmission (3) including a plurality of planetary gear mechanisms (7, 8), and the input shaft (1) and the output shaft (2) are arranged in parallel with each other, and the input side of the input shaft ( A hydrostatic transmission (4) connected to the output shaft (2) via the mechanical transmission (3) and connected to the output shaft (2). The hydrostatic transmission (4) An input-side hydraulic pump (5) that converts a rotational force input from the input shaft (1) to the pump shaft (52) into a predetermined discharge pressure liquid by controlling a change in increase or decrease of a swash plate angle of the plate (51); The swash plate (61) in a predetermined inclined state allows the hydraulic pump (5)
A hydraulic motor (6) on the output side for converting a pressure fluid discharged from the motor into a rotational force and rotating a motor shaft (62);
And operating the hydrostatic transmission (4) in a plurality of operation modes according to the gear ratio,
In the continuously variable transmission configured to continuously change the input rotation input to the input shaft (1) and transmit the input rotation to the output shaft (2), the motor shaft of the hydrostatic transmission (4) 6
A first motor clutch mechanism (17) for connecting the second transmission to the mechanical transmission (3) in an intermittent manner.
And when the rotational speed of the output shaft (2) is at a specific rotational speed,
Lock-up switching control means (19) for switching from the normal operation state to a lock-up operation in which power is transmitted only from the input shaft (1) to the output shaft (2) via the mechanical transmission (3); Lock-up release control means (1) for performing switching control to release the lock-up operation and return to the normal operation.
9), wherein the lock-up switching control means (19) includes a first motor clutch disconnection control unit that switches the first motor clutch mechanism (17) from a connected state to a disconnected state, and the hydraulic pump ( 5) a swash plate angle change control unit that changes the swash plate angle to zero when the swash plate angle of the variable swash plate (51) is not zero in accordance with the switching control by the first motor clutch cutoff control unit; The lock-up release control means (19) is configured to change the swash plate angle of the variable swash plate (51) changed by the swash plate angle change control unit to the swash plate angle at the time of switching to the lock-up operation. A swash plate angle return control unit for returning the first motor clutch mechanism (17) from a disconnected state to a connected state in a state where the swash plate angle of the variable swash plate (51) is restored by the swash plate angle return control unit; Switch to the first CVT, characterized in that it comprises a Takuratchi connection control unit. 2. A motor shaft (62) according to claim 1, wherein the motor shaft (62) of the hydrostatic transmission (4).
And a second motor clutch mechanism (1) for switching between a fixed state pressed against the non-rotating part (103) and a free rotating state separated from the rotating part (103).
8), and the lock-up switching control means (19) switches the second motor clutch mechanism (18) from the free rotation state in a state where the normal operation is switched to the lock-up operation and the rotation of the motor shaft is stopped. A second motor clutch fixing control unit for switching to a fixed state, wherein the lock-up release control means (19) includes a variable swash plate (5);
(1) A continuously variable transmission comprising a second motor clutch release control section for switching the second motor clutch mechanism (19) from a fixed state to a free rotation state when the swash plate angle is zero. 3. The gear connection mechanism (56) according to claim 1, which is disposed in parallel with the input shaft (1) and the output shaft (2), and is provided on the input side of the hydrostatic transmission (4). , 114) and a connection end (75) on the mechanical transmission (3) side to which the output side of the hydrostatic transmission (4) is connected so as to be able to intermittently switch, thereby transmitting a rotational power. (15)
The lock-up switching control means (19) includes a bypass operation control section for switching the bypass mechanism (15) to the connection state at the highest speed ratio position in the normal operation, and the lock-up release control means (19). ) Is a bypass that switches the bypass mechanism (15) to a cut-off state in synchronization with control for returning the rotational power from the motor shaft (62) of the hydraulic motor (6) to the mechanical transmission (3). A continuously variable transmission comprising a release control unit. 4. A normal operation control means according to claim 1, further comprising: a swash plate angle of the variable swash plate (51) of the hydraulic pump (5) divided into at least three operation modes and controlled to increase or decrease. The normal operation control means is configured to control the first operation in the low speed ratio range from the start.
In the first mode, the variable swash plate has an increase / decrease change ratio such that the swash plate angle becomes a neutral position at the minimum value of the speed ratio range of the first mode and the maximum swash plate angle in the tilt direction (-) at the maximum value. The swash plate angle of (51) is changed, and in the second mode of the speed ratio range higher than the first mode, the (-) side maximum swash plate angle becomes the above-mentioned (-) maximum swash plate angle at the minimum value of the speed ratio range of the second mode. The variable swash plate (51) swash plate angle is changed at an increase / decrease change ratio such that the value becomes the neutral position and the maximum value becomes the maximum swash plate angle in the tilting direction (+), and is higher than in the second mode. In the third mode of the speed ratio range, the minimum value of the speed ratio range of the third mode is the maximum swash plate angle in the tilt direction (+), the intermediate value is the neutral position, and the maximum value is the tilt direction (-). The variable swash plate (51) is inclined at an increase / decrease change ratio such that the maximum swash plate angle on the The swash plate (61) of the hydraulic motor (6) is fixed to a swash plate angle that is equal in absolute value to both of the maximum swash plate angles. A switching speed corresponding to a switching speed ratio between the first mode and the second mode, an intermediate speed corresponding to an intermediate value in a speed ratio range of the second mode, and a second mode and a third mode. The switching speed corresponding to the switching speed ratio between the first mode, the intermediate speed corresponding to the intermediate value of the speed ratio range of the third mode, and the speed corresponding to the highest speed ratio of the third mode are A continuously variable transmission configured to switch from a normal operation to a lock-up operation as a specific rotation speed.