JP2004068974A - Hydraulic continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a conventional problem that when a housing of a servo mechanism is formed separately from the housing of an HST main body for providing the servo mechanism to a two-pump two-motor type HST, or an actuator for operating swash plate angle of a variable capacity hydraulic motor is formed separately from the housing of the HST main body, the HST becomes large in size and high in cost. <P>SOLUTION: A two-pump two-motor type hydraulic continuously variable transmission 1 respectively composed of a pair of hydraulic pumps 11, 21 and a pair of hydraulic motors 12, 22 is provided with the servo mechanism 61 for operating the hydraulic continuously variable transmission 1, and integrally formed with one housing 31. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a configuration of a hydraulic continuously variable transmission including a hydraulic pump and a hydraulic motor.
[0002]
[Prior art]
Conventionally, a hydraulic continuously variable transmission (hereinafter, HST) including one hydraulic pump and one hydraulic motor has been provided with a servo mechanism for operating the HST. In a two-pump two-motor type HST including a pair of a hydraulic motor and a hydraulic motor, no such servo mechanism is provided.
Further, in the conventional two-pump two-motor type HST, each motor is configured as a fixed displacement type.
[0003]
[Problems to be solved by the invention]
In the case where a servo mechanism is provided in a two-pump two-motor type HST, the housing of the servo mechanism is formed separately from the housing of the HST main body. If an actuator for operating the swash plate angle of the hydraulic motor is formed separately from the housing of the HST main body, the HST becomes large and the cost increases.
Further, in the conventional two-pump two-motor type HST, since the hydraulic motor is configured as a fixed displacement type, it is difficult to switch the sub-transmission during traveling in a vehicle equipped with the two-pump two-motor type HST.
[0004]
[Means for Solving the Problems]
The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
That is, in the first aspect, in a two-pump two-motor hydraulic continuously variable transmission configured by providing a pair of a hydraulic pump and a hydraulic motor, a servo mechanism for operating the hydraulic continuously variable transmission is provided. , And formed in a single housing.
[0005]
Further, in claim 2, the servo mechanism is disposed on both sides of a hydraulic continuously variable transmission main body.
[0006]
According to a third aspect of the present invention, at least one motor constituting the two-pump two-motor type hydraulic continuously variable transmission is a variable displacement motor capable of changing its capacity in two or multiple stages stepwise or continuously. To be configured.
[0007]
According to a fourth aspect of the present invention, the swash plate of the variable displacement motor is controlled at a constant horsepower.
[0008]
According to a fifth aspect of the present invention, a center portion of an oil passage plate of the two-pump two-motor hydraulic continuously variable transmission is fastened to a housing by a fastening member, and a portion between the oil passage plate and the housing at the fastening portion is provided. The interposed seal member and the seal member interposed between the oil passage plate and the housing at the outer peripheral portion of the housing are integrally formed of the same member.
[0009]
Further, in claim 6, a motor shaft constituting a hydraulic continuously variable transmission composed of a hydraulic pump and a hydraulic motor is an output shaft penetrating the hydraulic continuously variable transmission, and the output shaft is It is used as an output shaft for running a vehicle equipped with a hydraulic type continuously variable transmission and for taking out PTO.
[0010]
According to a seventh aspect of the present invention, a charging or servo control hydraulic circuit is formed on a mating surface between a housing of the hydraulic continuously variable transmission including a hydraulic pump and a hydraulic motor and an oil passage plate.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described.
FIG. 1 is a front sectional view showing a two-pump two-motor HST of the present invention, FIG. 2 is a side sectional view showing a first HST of a two-pump two-motor HST, and FIG. 4 is a front sectional view showing an oil passage plate, FIG. 5 is a side sectional view showing a motor servo mechanism, FIG. 6 is a rear view showing a housing, FIG. 7 is a top view of the same, and FIG. It is a front view which shows the sealing member interposed between a housing and an oil-path board.
[0012]
The configuration of the two-pump two-motor hydraulic continuously variable transmission according to the present invention will be described. A two-pump two-motor hydraulic continuously variable transmission (hereinafter referred to as HST) 1 shown in FIGS. 1 to 3 includes a first HST 10 including a hydraulic pump 11 and a hydraulic motor 12, a hydraulic pump 21 and a hydraulic motor. The second HST 20 constituted by the second HST 22 is arranged on one oil passage plate 32 shown in FIG.
The two-pump two-motor type HST 1 is mounted on a vehicle. For example, the first HST 10 is used for straight running, and the second HST 20 is used for turning.
[0013]
The hydraulic pump 11 constituting the first HST 10 includes a drive shaft 11a, a cylinder block 11b into which the drive shaft 11a is inserted and rotates together with the drive shaft 11a, a plunger 11e slidably inserted into the cylinder block 11b, and The movable swash plate 11c is in contact with the plunger 11e, and is configured as a variable displacement hydraulic pump.
The movable swash plate 11c regulates the sliding amount of the plunger 11e, and is configured to be able to adjust the discharge amount of the hydraulic oil of the hydraulic pump 11. A pair of main circuits 13m and 13m are formed in the first HST 10 portion of the oil passage plate 32, and hydraulic oil is supplied from the hydraulic pump 11 to the hydraulic motor 12 via the main circuit 13m.
[0014]
Similarly to the hydraulic pump 11, the hydraulic motor 12 is inserted into the oil passage plate 32, and one end of the output shaft 12a is rotatably supported by the housing 31, and the output shaft 12a is inserted and interlocked with the drive shaft 11a. It comprises a cylinder block 12b that rotates by rotation, a plunger 12e slidably inserted into the cylinder block 12b, and a movable swash plate 12c abutting on the plunger 12e.
The cylinder block 12b is configured to rotate together with the output shaft 12a, and a plunger 12e is slidably inserted into the cylinder block 12b. The plunger 12e is in contact with a movable swash plate 12c fixed to the housing 31.
[0015]
With the above configuration, the driving force is input to the driving shaft 11a, and the hydraulic pump 11 is driven. The hydraulic oil discharged by the hydraulic pump 11 is supplied to the hydraulic motor 12 via the main circuit 13m of the oil passage plate 32. The hydraulic motor 12 is driven by the supplied hydraulic oil, and the driving force is transmitted to the output shaft 12a.
[0016]
The output shaft 12a of the first HST 10 penetrates the housing 31 and the oil passage plate 32, and the end on the oil passage plate 32 side (the right end in FIG. 2) is a vehicle on which the two-pump two-motor type HST 1 is mounted. And the output from the output shaft 12a is used for straight running of the vehicle.
A pulley 18 that rotates integrally is attached to an end (left end in FIG. 2) of the output shaft 12 a on the side opposite to the oil passage plate 32, and an output from the output shaft 12 a via the pulley 18. Can be taken out to the outside. That is, the output shaft 12a is also used as an output shaft for taking out the PTO.
With this configuration, it is possible to obtain not only an output for traveling from the first HST 10 but also a PTO output such as an output for mowing drive.
[0017]
The swash plate angle of the movable swash plate 12 c can be adjusted by a motor servo mechanism 36, and the motor servo mechanism 36 is operated by an operation unit 45.
The motor servo mechanism 36 is housed in a motor servo mechanism housing part 31b formed integrally with the housing 31, and mainly has a servo piston 81 and a spool 82 arranged inside the servo piston 81. And a manual swash plate angle control valve 83.
The servo piston 81 is vertically slidably housed in the servo mechanism housing part 31b for the motor, and a pin shaft 84 protruding from the side of the movable swash plate 12c is fitted on a side surface of the servo piston 81. . The spool 82 is slidably fitted in a hole that penetrates the axis of the servo piston 81.
[0018]
An oil passage is formed in the servo piston 81 so as to allow the upper and lower portions of the servo piston 81 to communicate with each other. Alternatively, pressure oil is sent downward. As a result, the servo piston 81 slides up and down to move the pin shaft 84 up and down, and the swash plate angle of the movable swash plate 12c is adjusted.
One end of a pin 85 as a drive pin of the spool 82 is fitted on the upper portion of the spool 82. The other end of the pin 85 is fitted to the operation part piston 45b of the operation part 45.
[0019]
The operation section 45 is configured by slidably fitting an operation section piston 45b urged downward by a spring 45c in a casing 45a, and a pilot pressure is supplied to a pilot pressure introduction port 45d at a lower end. I have.
When the operating portion piston 45b slides upward against the urging force of the spring 45c due to the pilot pressure, the spool 82 slides upward via the pin 85, and as a result, the movable swash plate 12c becomes It is rotated in the direction in which it increases.
When the swash plate angle of the movable swash plate 12c of the hydraulic motor 12 increases, the rotation speed of the output shaft 12a decreases, and the vehicle is decelerated.
[0020]
Therefore, by changing the pilot pressure supplied to the pilot pressure introduction port 45d according to the load applied to the first HST 10 or the PTO, etc., the hydraulic motor 12 is controlled by adjusting the swash plate angle of the movable swash plate 12c. Is controlled to a constant horsepower, and stable running and work can be performed.
In addition, since the change in the pilot pressure supplied to the pilot pressure inlet 45d is continuously adjusted in multiple steps or continuously, the speed and torque of the vehicle can be controlled smoothly. It has become.
An electromagnetic valve 38 is attached to the lower end of the servo mechanism 36 for the motor. Apart from the operation by the operation unit 45, the servo piston 81 is vertically slid by the operation of the electromagnetic valve 38 to move the movable swash plate 12c. It is also possible to adjust the angle of the swash plate.
[0021]
On the other hand, the second HST 20 is provided with a hydraulic pump 21 including a drive shaft 21a, a cylinder block 21b into which the drive shaft 21a is inserted and rotating together with the drive shaft 21a, a plunger 21e slidably inserted into the cylinder block 21b, and The movable swash plate 21c is in contact with the plunger 21e, and is configured as a variable displacement hydraulic pump.
The movable swash plate 21c regulates the amount of sliding of the plunger 21e, and is configured to be able to adjust the amount of hydraulic oil discharged from the hydraulic pump 21. A pair of main circuits 23m and 23m are formed in the second HST 20 portion of the oil passage plate 32, and hydraulic oil is supplied from the hydraulic pump 21 to the hydraulic motor 22 via the main circuit 23m.
[0022]
Similarly to the hydraulic pump 21, the hydraulic motor 22 is inserted into an oil passage plate 32, and one end of the output shaft 22a is rotatably supported by the housing 31, and the output shaft 22a is inserted and rotated together with the drive shaft 22a. It comprises a moving cylinder block 22b, a plunger 22e slidably inserted in the cylinder block 22b, and a fixed swash plate 22c in contact with the plunger 22e.
The cylinder block 22b is configured to rotate together with the output shaft 22a, and a plunger 22e is slidably inserted into the cylinder block 22b. The plunger 22e is in contact with a movable swash plate 22c fixed to the housing 31.
[0023]
With the above configuration, the driving force is input to the driving shaft 21a, and the hydraulic pump 21 is driven. The hydraulic oil discharged from the hydraulic pump 21 is supplied to the hydraulic motor 22 via the main circuit 23m of the oil passage plate 32. The hydraulic motor 22 is driven by the supplied hydraulic oil, and the driving force is transmitted to the output shaft 22a.
[0024]
The first HST 10 and the second HST 20 configured as described above each include a pump servo mechanism 61 for adjusting the swash plate angle of the movable swash plate 11c of the hydraulic pump 11 and the movable swash plate 21c of the hydraulic pump 21. Is provided.
The pump servo mechanisms 61 are disposed on the left and right sides of the two-pump two-motor type HST 1, and are respectively housed in servo mechanism housing parts 31 a formed integrally with the housing 31.
[0025]
That is, the two-pump two-motor type HST 1 is formed integrally with the pump servo mechanisms 61 and 61 and the motor servo mechanism 36 in one housing 31.
By thus integrally configuring the two-pump two-motor type HST 1 as a whole, compared to a case where the pump servo mechanisms 61 and 61 formed separately from the housing 31 are attached to the housing 31, for example. The two-pump two-motor type HST 1 can be made compact, and the cost can be reduced.
In addition, since the pump servo mechanisms 61 are arranged on the left and right sides of the two-pump two-motor type HST1, the vertical dimension of the two-pump two-motor type HST1 can be reduced, and the vertical space is too small. It is easy to install in places where it cannot be taken large.
[0026]
The pump servo mechanism 61 is mainly composed of a piston 71 and a manual swash plate angle control valve 63 disposed inside the piston 71 and having a spool 72. The piston 71 is vertically slidably housed in a cylinder chamber 70 formed in the servo mechanism housing portion 31a, and a pin shaft 23 protruding from a side of the movable swash plate 21c is fitted to a side surface of the piston 71. Have been. The spool 72 is slidably fitted in a hole passing through the axial center portion of the piston 71.
[0027]
An oil passage communicating between the upper and lower portions of the cylinder chamber 70 is formed in the piston 71, and the oil passage is communicated or blocked by sliding of the spool 72 to send pressure oil to the upper and lower oil chambers of the piston 71. Oil is applied so that the piston 71 can slide up and down.
A pin 41 as a drive pin of the spool 72 is fitted to a lower portion of the spool 72. The pin 41 is linked and interlocked with the operation lever 50 via the neutral position holding mechanism 51, and the rotation of the operation lever 50 causes the pin 41 to rotate up and down, so that the spool 72 moves up and down. It is configured as follows.
Thus, the piston 71 slides up and down, and the swash plate angles of the movable swash plates 11c and 21c are adjusted via the pin shaft 23.
[0028]
At the upper end of the pump servo mechanism 61, an automatic swash plate angle control valve 62 constituted by an electromagnetic valve is attached. For example, an engine load or a foot connected to the drive shaft 21a of the first HST 10 is controlled. The automatic swash plate angle control valve 62 is switched according to the detected value of the surrounding load and the like, and the spool 72 is slid up and down according to the switching direction to adjust the swash plate angle of the movable swash plates 11c and 21c. Is also possible.
[0029]
A charge pump 49 that is rotationally driven by the drive shaft 21a of the second hydraulic pump 21 is attached to the housing 31 of the two-pump two-motor type HST1, and the housing 31 and the oil passage plate 32 are each provided with a charge circuit 31c. 32c is formed. Further, a filter 48 is directly mounted via a filter joint 47 on a filter base 31 e formed on the upper surface of the second HST 20 portion of the housing 31.
[0030]
The charge pump 49 sucks hydraulic oil from the suction port 49a and discharges it from the discharge port 49b. The hydraulic oil discharged from the discharge port 49b is guided to a filter 48 mounted on the upper surface of the second HST 20 portion of the housing 31 through a guide path 31d formed in the housing 31.
Then, after passing through the filter 48, it is supplied to the charge circuits 31c and 32c.
Further, the charge pump 49 is provided with a PTO port 49c, so that the hydraulic oil pumped from the charge pump 49 can be used for operating another working machine.
[0031]
As shown in FIGS. 6 and 7, a charge circuit 31c formed in the housing 31 is branched into two from a base 31e for a filter on which a filter 49 is mounted. At the mating surface A with the oil passage plate 32, the charge circuit 32c on the first HST 10 side and the charge circuit 32c on the second HST 20 side of the oil passage plate 32 are connected.
[0032]
In the housing 31, servo oil passages 31g and 31h for guiding pressure oil to a servo mechanism housing portion 31a in which the servo mechanism 61 is housed are formed. For example, the servo oil passage 31g is formed by the mating surface A of the housing 31. Is connected to the charge circuit 32c by a communication oil passage 31f formed in a groove shape.
In this way, by forming the communication oil passage 31f connecting the charge circuit 32c and the servo oil passage 31g on the mating surface A, the formation of the connection oil passage becomes easy, and the operation to the servo mechanism 61 can be performed with a simple configuration. It is possible to supply oil.
[0033]
A check relief valve 35 is interposed between the charge circuit 32c, the main circuits 13m and 13m of the first HST 10, and the main circuits 23m and 23m of the second HST 20, respectively.
Then, when the working oil in the main circuits 13m and 23m is insufficient, the working oil is supplied from the charge circuit 32c to the main circuits 13m and 23m via the check and relief valve 35.
Further, the check / relief valve 35 is configured to open when the pressure of the main circuits 13m and 23m becomes larger than a predetermined value, and to release the hydraulic oil to the charge circuit 32c.
That is, the check / relief valve 35 has both a check valve function and a relief valve function.
[0034]
The charge circuit 32c is provided with a charge relief valve 39 (shown in FIG. 3). When the pressure in the charge circuit 32c exceeds a predetermined pressure, the charge relief valve 39 is opened and the operation in the charge circuit 32c is started. The oil is allowed to escape into the housing 31.
[0035]
The housing 31 and the oil passage plate 32 are fastened by a fastening member such as a bolt, and a seal member 42 shown in FIG. 8 is interposed between the housing 31 and the oil passage plate 32.
The fastening by the fastening member is performed by inserting the fastening member into outer circumferential fastening holes 31 m, 42 m, and 32 m arranged on the outer circumference of the housing 31, the seal member 42, and the oil passage plate 32. This is performed by inserting a fastening member into central fastening holes 31n, 42n, and 32n arranged at the center of the oil passage plate 32.
That is, the housing 31 and the oil passage plate 32 are fastened by the fastening members not only at the outer periphery but also at the center.
[0036]
Here, the pressure of the hydraulic oil in the housing 31 is applied to the oil passage plate 32 fastened to the housing 31 in a direction in which the oil passage plate 32 and the housing 31 are separated from each other. If the oil passage plate 32 is fastened only at the outer peripheral portion, the central portion of the oil passage plate 32 may float on the housing 31.
However, since the oil passage plate 32 is fastened not only to the outer peripheral portion but also to the center portion of the housing 31, even if the pressure of the hydraulic oil in the housing 31 is applied to the central portion of the oil passage plate 32, the oil The road plate 32 can be prevented from floating with respect to the housing 31.
[0037]
The seal member 42 interposed between the oil passage plate 32 and the housing 31 includes an outer peripheral portion 42a in which an outer peripheral portion fastening hole 42m is formed and a central portion 42b in which a central portion fastening hole 42n is formed. It is formed integrally.
Therefore, when the central portion of the oil passage plate 32 is fastened, the number of components can be reduced as compared with the case where the outer peripheral portion 42a and the central portion 42b of the seal member 42 are formed separately, and the oil passage plate 32 Can be easily assembled, such as fastening to the housing 31.
[0038]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained. That is, in a two-pump two-motor hydraulic continuously variable transmission configured by providing a pair of a hydraulic pump and a hydraulic motor, a servo for operating the hydraulic continuously variable transmission is provided. As it has a mechanism and is formed as an integral structure in one housing,
For example, compared to a case where a pump servo mechanism formed separately from the housing is attached to the housing, the two-pump two-motor type HST can be made more compact, and the cost can be reduced.
[0039]
Furthermore, since the servo mechanism is arranged on both sides of the hydraulic continuously variable transmission main body as described in claim 2,
The vertical dimension of the two-pump two-motor type HST can be reduced, and it becomes easy to install the HST in a place where a space in the vertical direction is not so large.
[0040]
Further, as set forth in claim 3, at least one motor constituting the two-pump two-motor hydraulic continuously variable transmission has a variable displacement capable of changing the displacement in two or multiple stages or continuously. Since it is configured as a type motor,
It is possible to smoothly control the speed and torque of the vehicle.
[0041]
Further, since the swash plate of the variable displacement motor is controlled at a constant horsepower, stable running and work can be performed.
[0042]
Further, as set forth in claim 5, a central portion of an oil passage plate of the two-pump two-motor type hydraulic continuously variable transmission is fastened to a housing by a fastening member, and the oil passage plate and the housing at the fastening portion are connected to each other. Since the seal member interposed therebetween and the seal member interposed between the oil passage plate and the housing in the outer peripheral portion of the housing are integrally formed by the same member,
The number of parts can be reduced, and assembly work such as fastening the oil passage plate to the housing can be facilitated.
[0043]
Further, as set forth in claim 6, a motor shaft constituting a hydraulic continuously variable transmission composed of a hydraulic pump and a hydraulic motor is an output shaft penetrating the hydraulic continuously variable transmission, Is used as an output shaft for traveling and PTO take-out of a vehicle equipped with a hydraulic continuously variable transmission.
It is possible to obtain not only an output for traveling from one HST but also a PTO output such as an output for mowing drive.
[0044]
Further, a charging or servo control hydraulic circuit is formed on a mating surface of a housing and an oil passage plate of a hydraulic type continuously variable transmission composed of a hydraulic pump and a hydraulic motor. So
The formation of the hydraulic circuit is facilitated, and the supply of hydraulic oil for charging or for controlling the servo mechanism can be performed with a simple configuration.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a two-pump two-motor type HST of the present invention.
FIG. 2 is a side sectional view showing a first HST of a two-pump two-motor type HST.
FIG. 3 is a side sectional view showing a second HST of a two-pump two-motor type HST.
FIG. 4 is a front sectional view showing an oil passage plate.
FIG. 5 is a side sectional view showing a servo mechanism for a motor.
FIG. 6 is a rear view showing the housing.
FIG. 7 is a top view similarly.
FIG. 8 is a front view showing a seal member interposed between the housing and the oil passage plate.
[Explanation of symbols]
1 2 pump 2 motor type HST
10 First HST
12a Output shaft 20 Second HST
13m / 23m Main circuit 31 Housing 32 Oil passage board 31c / 32c Charge circuit 36 Servo mechanism for motor 49 Charge pump 61 Servo mechanism 61 for pump

Claims (7)

In a two-pump two-motor hydraulic continuously variable transmission configured by providing a pair of a hydraulic pump and a hydraulic motor, a servo mechanism for operating the hydraulic continuously variable transmission is provided and one housing is provided. A two-pump two-motor hydraulic continuously variable transmission characterized in that it is formed in a single-piece structure. The two-pump two-motor hydraulic continuously variable transmission according to claim 1, wherein the servo mechanism is disposed on both sides of a hydraulic continuously variable transmission main body. At least one motor constituting the two-pump two-motor type hydraulic continuously variable transmission is configured as a variable displacement motor whose capacity can be changed stepwise or continuously in two or multiple stages. The two-pump two-motor hydraulic continuously variable transmission according to claim 1 or 2. The two-pump two-motor hydraulic continuously variable transmission according to claim 3, wherein the swash plate of the variable displacement motor is controlled at a constant horsepower. A sealing member interposed between the oil passage plate and the housing at the fastening portion, the center portion of the oil passage plate of the two-pump two-motor hydraulic continuously variable transmission being fastened to the housing with a fastening member; 5. The seal according to claim 1, wherein the seal member interposed between the oil passage plate and the housing in the outer peripheral portion of the housing is integrally formed of the same member. Pump 2 motor type hydraulic continuously variable transmission. A motor shaft that constitutes a hydraulic continuously variable transmission composed of a hydraulic pump and a hydraulic motor is used as an output shaft that penetrates the hydraulic continuously variable transmission, and the output shaft is mounted on the hydraulic continuously variable transmission. A hydraulic continuously variable transmission characterized by being used for an output shaft for running a vehicle and for taking out a PTO. A hydraulic continuously variable transmission characterized in that a hydraulic circuit for charging or servo control is formed on a mating surface between a housing of a hydraulic continuously variable transmission composed of a hydraulic pump and a hydraulic motor and an oil passage plate. Machine.

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