JPH11190413A - Transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form hydraulic drive means in which a rotating speed difference is given to an output shaft and gear shift is carried out by a fixed displacement hydraulic pump, a fixed displacement hydraulic motor, and a control valve, each of which is separately disposed, and has a general purpose property for corresponding with a change in a attaching specification, and to reduce the cost by inexpensive constitution. SOLUTION: In a transmission which combines an output of mechanical drive means M and an output of hydraulic drive means P, makes a driving speed of an output shaft 13 adjustable and carries out a gear shift of vehicle speed, the hydraulic drive means P which gives a rotation to an epicycle gear mechanism 8 is constituted of a fixed displacement hydraulic pump 3, a control valve 14 connected to the fixed displacement hydraulic pump 3, and a fixed displacement hydraulic motor 15 connected to the control valve 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission for a traveling work machine such as a combine or a bulldozer.

[0002]

2. Description of the Related Art Conventionally, as a transmission of this type, for example, as shown in FIG. 5, power of an engine 1 or the like is transmitted as rotational power to a planetary gear mechanism 8 via a transmission 2, a clutch 4, and a shaft 5. With Engine 1
Power from a hydraulic drive means such as a hydrostatic transmission (HST) in which the variable displacement hydraulic pump 3 and the variable displacement hydraulic motor 15 are integrally formed in a closed circuit, and the rotational power from the transmission 2 Are combined as a differential mechanism by the planetary gear mechanism 8, and the ring gear 12, the shaft 7, the bevel gears 6a, 6
b, there is a vehicle in which a difference in rotational speed is given to the output shaft 13 to rotate the wheel 13A to change the vehicle speed.

[0003]

By the way, in the above conventional example, the rotational power from a hydrostatic transmission (hereinafter, referred to as HST) in which a variable displacement hydraulic pump and a variable displacement hydraulic motor are formed in a closed circuit. HST is applied to the planetary gear mechanism.
Since the variable displacement hydraulic pump and the variable displacement hydraulic motor are connected in a closed circuit and integrated, the input shaft on the hydraulic pump side and the output shaft on the hydraulic motor side are regulated and provided.
There is a problem in that when the vehicle is mounted on another vehicle model, there are restrictions on the mounting positional relationship and the like, so that the vehicle cannot be diverted to another vehicle model or cannot easily respond to a change in specifications. Also, the HST uses a variable displacement hydraulic pump and a variable displacement hydraulic motor, and is more expensive than a fixed displacement hydraulic pump and motor. However, there is also a problem that it is difficult to achieve.

In view of the above, the present invention provides a hydraulic drive means for giving a rotational speed difference to an output shaft to change the speed by using a constant displacement hydraulic pump, a constant displacement hydraulic motor, a control valve and the like, and individually disposed. Therefore, it is an object of the present invention to provide versatility so as to be able to cope with a change in mounting specifications, and to reduce the cost by configuring it at low cost.

[0005]

According to a first aspect of the present invention, power from a mechanical drive means including a transmission for transmitting the output of an engine is transmitted to an output shaft via a planetary gear mechanism. The power from the hydraulic drive unit including the driven variable displacement hydraulic pump and the variable displacement hydraulic motor is transmitted so as to impart rotation to the planetary gear mechanism, and the mechanical drive unit and the hydraulic drive unit are transmitted. The output of the output shaft, the drive speed of the output shaft is configured to be adjustable, in a transmission that changes the vehicle speed of the vehicle, the planetary gear mechanism and the hydraulic drive means for applying rotation to the constant displacement hydraulic pump, It comprises a control valve connected to the constant displacement hydraulic pump and a constant displacement hydraulic motor connected to the control valve.

According to a second aspect of the present invention, power from a mechanical drive means including a transmission for transmitting the output of the engine is transmitted to an output shaft via a planetary gear mechanism, and a variable displacement type driven by the engine is provided. The power from the hydraulic drive means comprising a hydraulic pump and a variable displacement hydraulic motor is transmitted to impart rotation to the planetary gear mechanism, and the outputs of the mechanical drive means and the hydraulic drive means are combined, In a transmission configured to be capable of adjusting the drive speed of the output shaft and shifting the vehicle speed of the vehicle, a hydraulic drive unit that applies rotation to the planetary gear mechanism is a constant displacement hydraulic pump, and a constant displacement hydraulic pump. The control valve includes a control valve connected thereto, a constant displacement hydraulic motor connected to the control valve, and a flow control valve with pressure compensation provided in a connection line between the constant displacement hydraulic pump and the control valve.

According to a third aspect of the present invention, power from a mechanical drive means including a transmission for transmitting the output of an engine is transmitted to an output shaft via a planetary gear mechanism, and a variable displacement type driven by the engine is provided. The power from the hydraulic drive means comprising a hydraulic pump and a variable displacement hydraulic motor is transmitted to impart rotation to the planetary gear mechanism, and the outputs of the mechanical drive means and the hydraulic drive means are combined, In a transmission configured to be capable of adjusting the drive speed of the output shaft and shifting the vehicle speed of the vehicle, a hydraulic drive unit that applies rotation to the planetary gear mechanism is a constant displacement hydraulic pump, and a constant displacement hydraulic pump. It is composed of a control valve with pressure compensation connected thereto and a constant displacement hydraulic motor connected to the control valve with pressure compensation.

In a fourth aspect, the control valve in the hydraulic drive means is an open center type 4-port 3-position control valve or an open center type 6-port 3-position control valve.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same components as those of the conventional example will be denoted by the same names and symbols.

In the transmission according to this embodiment, as shown in FIG. 1, reference numeral 1 denotes a prime mover such as an engine, and a transmission 2 and a clutch 4 are provided on the output side of the prime mover 1, respectively. And constitutes the mechanical drive means M.

A shaft 5 for directly transmitting rotational power from the engine 1 is connected to one end of the clutch 4, and the shaft 5 is joined to a wrist 9 of a planetary gear mechanism 8.

A planetary gear 10 is rotatably supported on the bracelet 9.

The planetary gear 10 rotates by meshing with a sun gear 11 and a ring gear 12 which are coaxially inserted into the shaft 5.

A bevel gear 6a is connected to a shaft 7 provided at one end of the ring gear 12, and the bevel gear 6a is
It is for meshing with.

An output shaft 13 is connected to the bevel gear 6b.
A pair of wheels 13A is attached to the output shaft 13,
The rotational power from the engine 1 is transmitted directly to the wheel 1
3A is rotated to drive the vehicle.

The transmission 2 is connected to a constant displacement hydraulic pump (hereinafter referred to as a hydraulic pump) 3. The hydraulic pump 3 is connected to a tank T on the suction side and to a control valve 14 on the discharge side. ing.

The control valve 14 has a manual four-port (a,
b, c, d) A closed center type control valve at three positions (A, B, C).

Downstream of the control valve 14 is a hydraulic motor 15
Are connected, and the hydraulic pump 3, the control valve 14, and the hydraulic motor 15 constitute a hydraulic drive unit P.

The transmission gear 1 is mounted on a shaft 16 of the hydraulic motor 15.
7 are coupled and a brake 18 is provided.

The transmission gear 17 further includes a gear 1
9 meshes with the sun gear 11, and the sun gear 11
The planetary gear 10 is also meshed.

The brake 18 brakes the rotation of the hydraulic motor 15 by an actuator (not shown).

Next, the operation will be described. Now, when the vehicle (not shown) is in a stopped state, the clutch 4 is disconnected, the rotational power from the engine 1 is not transmitted to the output shaft 13, and the brake 18 provided on the shaft 16 of the hydraulic motor 15 is provided. Thus, the rotation of the hydraulic motor 15 is stopped.

Further, the oil discharged from the hydraulic pump 3 is returned to the tank T with the control valve 14 at the position C, and the hydraulic motor 15 is stopped by being blocked at the center by no hydraulic pressure.

Next, when the vehicle is running, the clutch 4 that has been disconnected in the above-mentioned stopped state is gradually connected, and the rotational power from the engine 1 is supplied to the shaft 5, the arm ring 9 of the planetary gear mechanism, and the planetary gear 10 , The ring gear 12, the shaft 7, the bevel gears 6a and 6b, and the output shaft 13 to rotate the wheel 13A to allow the vehicle to travel.

When the vehicle speed is changed, the brake 18 provided on the output shaft 16 of the hydraulic motor 15 is released, and the control valve 14 is operated to move the hydraulic motor 15 to the position A (temporarily in the same rotational direction as the rotation of the wheel 13A). 15 is rotated), the hydraulic oil from the hydraulic pump 3 is
5, the hydraulic motor 15 rotates, and the gears 17, 1
9, the planetary gear 10 is combined with the planetary gear 10 via the sun gear 11, and a difference is generated between the direct rotational power from the engine 1 and the rotation from the hydraulic motor 15, so that the ring gear 12, the shaft 7, the bevel gear 6
a, 6b, the output shaft 13, and the rotation of the wheel 13A can be decelerated and travel.

When the control valve 14 is switched to the position B (assuming that the hydraulic motor rotates in the direction opposite to the rotation of the wheel 13A), the hydraulic oil from the hydraulic pump 3 is supplied to the hydraulic motor 15, The hydraulic motor 15 rotates and cooperates with the planetary gear 10 via the gears 17 and 19 and the sun gear 11, and the direct rotational power from the engine 1 and the hydraulic motor 1
There is a difference between the rotation from the rotation from 5 and the ring gear 12,
Via the shaft 7, the bevel gears 6a and 6b, and the output shaft 13, the rotation of the wheel 13A can be accelerated to travel.

As described above, in the transmission configured to be able to adjust the drive speed of the output shaft 13 and to change the vehicle speed, the hydraulic drive means P for imparting rotation to the planetary gear mechanism 8 includes a constant displacement hydraulic pump. 3, a control valve 14 connected to the constant displacement hydraulic pump 3, and a hydraulic motor 15 connected to the control valve 14.
Therefore, the variable displacement hydraulic pump and the variable displacement hydraulic motor are individually provided without being integrated, as in the HST shown in the conventional example. Since there is no restriction on the output shaft on the motor side, when mounting on other models, there are few restrictions on the mounting positional relationship, etc. It can be easily handled.

Further, the constant displacement pump 3 and the constant displacement motor 15 are used as the hydraulic pump and the hydraulic motor, and are inexpensive as compared with the variable displacement hydraulic pump and the variable displacement motor. The cost ratio in the whole can be reduced, and the cost can be reduced.

Next, a second embodiment shown in FIG.
Only the structure of a hydraulic drive unit in which a flow control valve is disposed between a hydraulic pump and a control valve in the hydraulic drive unit of the first embodiment is different from that of the first embodiment. This embodiment is the same as that of the first embodiment, and here, only a different configuration will be described, and details of other components will be omitted.

Therefore, the transmission of the second embodiment is
A flow control valve with variable pressure compensation (hereinafter referred to as a flow control valve) 2 between a pipeline 20a connecting the hydraulic pump 3 and the control valve 14 in the hydraulic driving means P in the first embodiment.
1, the discharge oil of the hydraulic pump 3 is supplied to a hydraulic motor 15 via a flow control valve 21 and a control valve 14 so as to rotate the hydraulic motor 15. The same operation and effect as those of the embodiment can be achieved, and even if the rotation of the engine 1 fluctuates and the discharge amount of the hydraulic pump 3 fluctuates, the oil at a constant flow rate is compensated by the flow control valve 21 with pressure compensation. The flow rate at the operation opening of the control valve 14 is supplied to the hydraulic motor 15, so that the rotation of the hydraulic motor 15 can be controlled with high accuracy.

A third embodiment shown in FIG.
Instead of the control valve in the hydraulic drive means in the first embodiment, a manual or electric pressure-compensated control valve (hereinafter referred to as a pressure-compensated control valve) comprising a flow dividing valve, a check valve, and a control valve at 6 ports and 3 positions. Only the structure of the hydraulic drive means provided with a control valve) is different.
This embodiment is the same as that of the first embodiment, and here, only a different configuration will be described, and details of other components will be omitted.

Therefore, the transmission according to the third embodiment comprises:
The control valve 1 disposed between the pipeline 20a connecting the hydraulic pump 3 and the hydraulic motor 15 in the first embodiment.
4, a manual or electric pressure-compensated control valve 22 (hereinafter referred to as a pressure-compensated control valve) including a flow dividing valve 22b, a check valve 22c, and a control valve 22a is provided. Of oil discharged from the control valve 2 with pressure compensation
2 is supplied to the hydraulic motor 15 via the hydraulic motor 15.
Is rotated, and the excess flow rate is
It is always returned to the tank T via b.

Even if the rotation of the engine 1 fluctuates and the discharge amount of the hydraulic pump 3 fluctuates, the same operation and effect as those of the first embodiment can be obtained, and the pressure-compensated control valve 22 can be used. The oil at a constant pressure is compensated, the flow rate at the operation opening of the control valve 14 is maintained, the rotation of the hydraulic motor 15 can be controlled with high accuracy, the gear can be shifted, and the excess flow rate of the hydraulic pump 3 is divided. It is always returned to the tank T via the valve 22b, which can help save energy.

Further, the fourth embodiment shown in FIG. 4 (a) is similar to the hydraulic drive means P in the first and second embodiments.
Open center type 4 instead of the control valve 14
The port 3 is a position change valve 24, the control valve 24 is in the neutral position C, the upstream side and the flow path connected to the downstream hydraulic motor 15 communicate with the tank T, the hydraulic pump 3 is unloaded, and the load of the engine 1 is reduced. Can be reduced and energy can be saved.

A sixth embodiment shown in FIG. 4 (b) is a hydraulic drive means P according to the first and second embodiments.
Is an open center type 6 port 3 position control valve 25 which replaces the control valve 14 in FIG.
In this case, a hydraulic motor (not shown) communicates with the tank T side to be in a floating state, and the hydraulic pump 3
By supplying the pressure oil to another device (not shown), the surplus hydraulic power can be effectively used.

[0036]

According to the first aspect of the present invention, there is provided a transmission for combining the outputs of a mechanical drive unit and a hydraulic drive unit so as to adjust the drive speed of an output shaft, and for shifting the vehicle speed of a vehicle. The hydraulic drive means for imparting rotation to the planetary gear mechanism comprises a constant displacement hydraulic pump, a control valve connected to the constant displacement hydraulic pump, and a constant displacement hydraulic motor connected to the control valve. As a result, the fixed displacement hydraulic pump and the fixed displacement hydraulic motor are individually arranged without being integrated, and the input shaft on the fixed displacement hydraulic pump side and the output shaft on the fixed displacement hydraulic motor side Is not restricted, so when installing it on other models, there are few restrictions on the mounting positional relationship, etc., and it can be diverted to other models or easily responded to changes in specifications Can be. In addition, fixed displacement pumps and fixed displacement motors are used as hydraulic pumps and motors, so they are inexpensive compared to variable displacement hydraulic pumps and variable displacement motors, making it possible to reduce the cost ratio of the entire system. This has the effect of reducing costs.

According to the second aspect of the present invention, in a transmission for shifting the vehicle speed of a vehicle, the output of the mechanical drive unit and the output of the hydraulic drive unit are combined to adjust the drive speed of the output shaft. A hydraulic drive means for imparting rotation to the gear mechanism; a constant displacement hydraulic pump; a control valve connected to the constant displacement hydraulic pump; a constant displacement hydraulic motor connected to the control valve; Because it was configured with a flow control valve with pressure compensation provided in the connection pipe between the pump and the control valve,
The same operation and effects as those of the first embodiment can be obtained, and even if the rotation of the engine fluctuates and the discharge amount of the pump fluctuates, the oil at a constant flow rate is compensated by the flow control valve with pressure compensation. , The flow rate at the operation opening of the control valve is kept constant,
Therefore, there is an effect that the rotation of the hydraulic motor can be controlled with high accuracy.

According to the third aspect of the present invention, there is provided a transmission in which the outputs of the mechanical drive unit and the hydraulic drive unit are combined, the drive speed of the output shaft is adjustable, and the speed of the vehicle is shifted. A hydraulic drive means for applying rotation to the gear mechanism and a constant displacement hydraulic pump, a control valve with pressure compensation connected to the constant displacement hydraulic pump, and a constant displacement hydraulic motor connected to the control valve with pressure compensation With the configuration described above, the same operation and effect as those of the first embodiment can be obtained, and the rotation of the engine fluctuates.
Even if the discharge pressure of the hydraulic pump fluctuates, oil at a constant pressure is compensated by the control valve with pressure compensation, the flow rate at the operation opening of the control valve is maintained, and the rotation of the hydraulic motor can be controlled with high accuracy. In addition, the vehicle can be shifted at a variable speed, and the surplus flow rate of the hydraulic pump is always returned to the tank via the flow dividing valve, which has the effect of saving energy.

According to the fourth aspect of the present invention, since the control valve in the hydraulic drive means is an open center type 4-port 3-position control valve, the control valve is connected to the upstream and downstream hydraulic motors at the neutral position. Communicates with the tank T, the hydraulic motor communicates with the tank T and floats, and the hydraulic pump has no load, thereby reducing the load on the engine and contributing to energy saving. In addition, since the open center type 6 port 3 position control valve is used, the hydraulic motor is in the neutral position of the control valve, communicates with the tank T side, makes it float, and uses the hydraulic oil of the hydraulic pump for other equipment. To supply the excess hydraulic power effectively.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a transmission according to a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a transmission according to a second embodiment.

FIG. 3 is a hydraulic circuit diagram of a transmission according to a third embodiment.

FIG. 4 (a) is a three-port three-position control valve also used for hydraulic drive means. (B) A 6-port, 3-position control valve also used for hydraulic drive means.

FIG. 5 is a hydraulic circuit diagram of a transmission showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 3 Hydraulic pump 4 Clutch 5 Shaft 6a Bevel gear 6b Bevel gear 7 Shaft 8 Planetary gear mechanism 9 Arm ring 10 Planetary gear 11 Sun gear 12 Ring gear 13 Output shaft 13A Wheel 14 Control valve 15 Hydraulic motor 16 Shaft 17 Transmission gear 18 Brake 19 Gear 20a Pipe 20b Pipe 21 Flow control valve with pressure compensation 22 Pressure compensation control valve 22a Control valve 22b Dividing valve 22c Check valve 24 Control valve 25 Control valve M Mechanical drive means P Hydraulic drive means T tank

Claims (4)

[Claims] 1. A system for transmitting power from a mechanical drive means including a transmission for transmitting the output of an engine to an output shaft via a planetary gear mechanism.
The power from a hydraulic drive unit including a variable displacement hydraulic pump and a variable displacement hydraulic motor driven by an engine is transmitted to the planetary gear mechanism so as to impart rotation, and the mechanical drive unit and the hydraulic drive are transmitted. In a transmission configured to synthesize the output of the output means and adjust the drive speed of the output shaft and to change the vehicle speed of the vehicle, a hydraulic drive means for imparting rotation to the planetary gear mechanism includes a constant displacement hydraulic pump. And a control valve connected to the constant displacement hydraulic pump, and a constant displacement hydraulic motor connected to the control valve. 2. A structure for transmitting power from a mechanical drive means including a transmission for transmitting the output of an engine to an output shaft via a planetary gear mechanism.
The power from a hydraulic drive unit including a variable displacement hydraulic pump and a variable displacement hydraulic motor driven by an engine is transmitted to the planetary gear mechanism so as to impart rotation, and the mechanical drive unit and the hydraulic drive are transmitted. In the transmission for changing the vehicle speed of the vehicle, the hydraulic drive means for imparting rotation to the planetary gear mechanism includes a constant displacement hydraulic pump and , A control valve connected to a constant displacement hydraulic pump, a constant displacement hydraulic motor connected to the control valve, and a flow control valve with pressure compensation provided in a connecting line between the constant displacement hydraulic pump and the control valve A transmission device comprising: 3. A structure for transmitting power from a mechanical drive means including a transmission for transmitting the output of an engine to an output shaft via a planetary gear mechanism.
The power from a hydraulic drive unit including a variable displacement hydraulic pump and a variable displacement hydraulic motor driven by an engine is transmitted to the planetary gear mechanism so as to impart rotation, and the mechanical drive unit and the hydraulic drive are transmitted. In the transmission for changing the vehicle speed of the vehicle, the hydraulic drive means for imparting rotation to the planetary gear mechanism includes a constant displacement hydraulic pump and A transmission comprising: a control valve with pressure compensation connected to a constant displacement hydraulic pump; and a constant displacement hydraulic motor connected to the control valve with pressure compensation. 4. The transmission according to claim 1, wherein the control valve in the hydraulic drive means is a closed center type 4-port 3-position control valve or an open center type 6-port 3-position control valve. .