JPS609487Y2 - hydraulic transmission - Google Patents

Description

[Detailed description of the invention] The present invention relates to a hydraulic transmission device consisting of a pump and an actuator. For example, when a single prime mover drives a vehicle drive shaft and a hydraulic transmission device, the vehicle drive shaft is An object of the present invention is to provide a hydraulic transmission device that can easily change gears during a speed change operation.

Generally, when a hydraulic transmission device is used to drive a mixer such as a mixer truck, the pump shaft of the hydraulic transmission device is connected to the PTO shaft of the transmission that drives the vehicle drive shaft, and one prime mover drives the vehicle. It is used to drive not only the drive shaft but also the hydraulic transmission device.

For this reason, there is a problem in that the gear change operation during the vehicle speed change operation becomes extremely heavy due to the load on the hydraulic transmission device.

In the past, a hydraulic transmission device having a closed circuit as shown in FIG. 1 has been proposed in order to deal with the above-mentioned problems.

That is, in order to bring the hydraulic transmission device into a no-load state during a speed change operation of a vehicle, a short-circuiting solenoid valve 1 is disposed between the pipes 4 and 5 constituting a closed circuit of the hydraulic transmission device, and the short-circuiting solenoid valve 1 The switching of the electromagnetic valve 1 is linked with the depression of the clutch.

However, in this type of conventional circuit, a charge pump 2 is provided to replenish the amount of leaked liquid that occurs in the closed circuit, and this charge pump 2 is provided so as to be driven by a prime mover E together with a hydraulic pump P. -ing

Therefore, even if the short-circuit solenoid valve 1 is interposed to disconnect the load 3 and the solenoid valve 1 is switched during a speed change operation to form a short circuit that directly connects the conduit 4 and the conduit 5. ,
Note that no-load loss due to the charge pump 2 is unavoidable.

Therefore, the problem of heavy change operations remained unsolved.

The present invention was devised to solve the above problems, and consists of connecting a hydraulic pump and an actuator through a pair of first and second pipes to form a closed circuit, and providing a power source to the pump. In the hydraulic transmission device, the drive shaft of the power source is connected only to the pump shaft of the hydraulic pump, so that only the hydraulic pump is driven by the power source. On the other hand, the first
A supply pipe having a pair of check valves that prevents the flow of liquid from each of these pipes is connected between the first and second pipes, and a portion of the supply pipe between the check valves is connected to the tank. On the other hand, a two-position electromagnetic valve having four ports is interposed in the second pipe line that is the inflow side of the pump, and when the electromagnetic valve is in one switching position, the pump in the second pipe line While communicating the side pipe and the actuator side pipe,
A pipe line branching from the first pipe line connected to the port of the solenoid valve and a pipe line communicating with the tank are closed, while in the other switching position, the actuator side pipe line is closed and the pump It is characterized in that the side pipe and the pipe line branching from the first pipe line are connected to the pipe line communicating with the tank.

An embodiment of the hydraulic transmission device of the present invention will be described below with reference to the drawings.

In FIG. 2, 6 is a hydraulic pump driven by a power source 7 such as an engine, and unlike the conventional device shown in FIG. A drive shaft is connected only to the hydraulic pump 6,
Only the pump 6 is driven by the power source 7.

Further, 8 is an actuator, mainly a motor, which is provided to drive a load 9 such as a mixer, and is communicated with the hydraulic pump 6 through a first pipe line 10 and a second pipe line 11, and is connected to the hydraulic pump 6 to control the hydraulic pressure. Pump 6, actuator 8 and first
The conduit 10 and the second conduit 11 form a closed circuit.

Reference numeral 12 denotes a two-position short-circuit solenoid valve having four ports, which is interposed in the middle of the second pipe line 11, and the pump of the second pipe line 11 is connected to two of the four ports. The 6 side pipe line 11a and the actuator 8 side pipe line 11b of the second pipe line 11 are connected, while a branch pipe line 13 branching from the first pipe line 10 and a tank 15 are connected to the other two ports. In the neutral position, the pump 6 side pipe line 1 in the second pipe line 11 is connected to the pipe line 15 that communicates with
1a and the actuator 8 side conduit 11b, and close the conduit 13 branching from the first conduit 10 and the conduit 14 communicating with the tank 15, while in the switching position, the actuator 8 side conduit 11b is closed, and the pipe line 13 branching from the pump 6 side pipe line 11a and the first pipe line 10 is connected to the pipe line 14 communicating with the tank 15.

Further, the short circuit solenoid valve 12 is configured to be switched in conjunction with the depression of a clutch (not shown).

Further, in order to supply liquid to the closed circuit instead of the charge pump, a supply pipe is provided between the first and second pipes 10 and 11 on the right side of the solenoid valve 12 and closer to the actuator 8 in the figure. Route 16 is connected.

This supply line 16 is provided with a pair of check valves 17 and 18 in order to prevent liquid from flowing in from the first line 10 and the second line 11. The valves 17 and 18 are connected to a liquid tank 20 via a supply pipe 19.

Note that a dotted line 21 in FIG. 2 is a drain passage formed between a pump casing and a motor casing of the hydraulic transmission device, and communicates with the supply pipe 19 and the tank 20 via a drain pipe 22.

In the embodiment shown in FIG. 2, the short-circuiting solenoid valve 12 is interposed between the piping of the hydraulic pump 6 and the actuator 8. Preferably, it is built into the end cap of the casing or attached to its external surface.

Further, the checks *17 and 18 can also be built into the end cap of the motor casing, and by doing so, there is no need to provide special piping to connect the solenoid valve 12 and the actuator 8. In addition, it is also possible to form a passage in the end cap for communication, thereby making it possible to reduce the hassle of piping work and simplify the structure.

When the power source 7 is driven to operate the hydraulic pump 6 in the above configuration, the liquid discharged from the pump 6 passes through the first pipe line 10 and is sent to the actuator 8,
When the actuator 8 is driven, a load 9 that is linked to the actuator 8 is actuated.

The liquid discharged by the actuator 8 is
It passes through the second pipe line 11 and flows into the hydraulic pump 6 via the short circuit solenoid valve 12 provided in the middle of the second pipe line 11.

In addition, the liquid flowing through the second circuit always leaks during the process of circulating the circuit and deviates from the closed circuit system.
In order to replenish this leaked liquid into the closed circuit, a charge pump 2 or the like was conventionally used as shown in Fig. 1, but in this embodiment of the present invention, the replenishment of the leaked liquid from the circuit is This is achieved by communicating the supply pipe 16 and the liquid tank 20 through the supply pipe 19.

In principle, this method utilizes the suction force generated on the liquid inflow side of the hydraulic pump 6 according to the amount of leaked liquid based on the relationship between the liquid discharge amount and the inflow amount of the liquid in the hydraulic pump 6. .

Therefore, the liquid leaked in the circuit is supplied from the liquid tank 20 into the second pipe line 11 by the presence of atmospheric pressure without requiring any power.

Next, when the clutch is depressed to change the speed of the vehicle, the short circuit solenoid valve 12 moves to the left (in the direction of arrow a in the figure) from the position shown in FIG. Conduit 10
and the pump 6 side pipe line 11a in the second pipe line 11 are communicated via the branch pipe line 13.
The pipe line 10 and the pump 6 side pipe line 11a are connected to the pipe line 1
4 to form a short circuit to the tank 20.

As a result, the actuator 8 becomes in a no-load operating state in which the load 9 on the side of the actuator 8 is disconnected.

Also, a second pipe line 11 from the actuator 8, that is, a pipe line 1 on the actuator 8 side in the second pipe line 11.
1b becomes a dead end at the short-circuit solenoid valve 12 at the stage where a short circuit is formed, and the actuator 8 is no longer able to discharge liquid.

Next, when the gear shift operation of the vehicle is completed and the clutch is released, the short circuit solenoid valve 12 returns to the state shown in FIG. 2, the short circuit is closed, and the flow of the entire circuit returns to the state described above. Return.

In the embodiment shown in FIG. 2, the leaked liquid is refilled to the second pipe line 11 by connecting the replenishing pipe line 16 with the tank 20 instead of using a charge pump as in the conventional case. During a vehicle speed change operation, the short-circuit solenoid valve 12 is switched by the clutch depression operation, creating a short circuit that disconnects the load 9, and performs a change operation in a no-load state, and also performs a shift operation in a no-load state. The charge pump, which was a major cause of no-load loss, was removed, making changing operations even easier.

Moreover, when forming this short circuit, the second pipe line 11 from the actuator 8 to the hydraulic pump 6
is closed in the short-circuiting solenoid valve 12, thereby preventing the load 9 from running on its own.

As described above, the present invention connects a hydraulic pump and an actuator through a pair of first and second pipes to form a closed circuit, and transmits the kinetic energy of the power source applied to the pump to the actuator. In a powerful hydraulic transmission device, the drive shaft of the power source is connected only to the pump shaft of the hydraulic pump, so that only the hydraulic pump is driven by the power source, and the first and second A supply pipe having a pair of check valves for blocking the flow of liquid from each of these pipes is connected between the pipes, and a portion of the supply pipe between the check valves is connected to a tank. A two-position electromagnetic valve having two ports is interposed in the second pipe line on the inflow side of the pump, and in one switching position of the electromagnetic valve, the second
One for communicating the pump-side pipe and the actuator-side pipe in the pipe, and closing a pipe that branches from the first pipe connected to the port of the solenoid valve and a pipe that communicates with the tank. , in the other switching position, the actuator side pipe is closed, and the pump side pipe and a pipe branching from the first pipe are connected to the pipe communicating with the tank. This allows leakage liquid to be replenished into the circuit naturally using atmospheric pressure without using a charge pump.
Moreover, since a short circuit can be formed that connects the first pipe line and the pump side pipe line in the second pipe line and opens to the tank, the hydraulic transmission device can be used for driving a mixer such as a mixer truck. In this case, the gear change operation of the vehicle can be performed extremely easily, thereby greatly improving the operability of the vehicle.

Furthermore, during this speed change operation, since the actuator side pipe in the second pipe is closed, the load connected to the actuator does not run on its own.

[Brief explanation of drawings]

FIG. 1 is a hydraulic power transmission circuit diagram showing a conventional hydraulic power transmission device, and FIG. 2 is a hydraulic power transmission circuit diagram showing an embodiment of the hydraulic power transmission device of the present invention. 6...Hydraulic pump, 8.asses actuator, 10...First pipe line, 11...Second pipe line, 11a...Curved pump side pipe line, 11b・・・・・・
・Actuator side pipe line, 16...supply pipe line,
17.18... check valve, 20------tank.

Claims (1)

[Scope of utility model registration request] The hydraulic pump 6 and the actuator 8 are connected by a pair of first and second pipes 10.11 to form a closed circuit, and the kinetic energy of the power source applied to the pump 6 is transferred to the actuator 8. In a hydraulic transmission device that transmits
The drive shaft of the power source is connected only to the pump shaft of the hydraulic pump 6, so that only the hydraulic pump 6 is driven by the power source, while a ,
l to block the flow of liquid from each of these pipes 10 and 11;
A supply line 16 having a pair of check valves 17 and 18 is connected, and the check valves 17 and 18 of this supply line 16 are connected to the tank 20, while a two-position solenoid valve having four ports is connected. 12 is interposed in the second pipe line 11 on the inflow side of the pump 6, and in one switching position of the solenoid valve 12, the pump 6 side pipe line 11a in the second pipe line 11 and the actuator 8 While connecting the side pipe 11b and closing the pipe 13 branching from the first pipe 10 connected to the port of the solenoid valve 12 and the pipe 14 communicating with the tank 15, the other switch is switched. At this position, the actuator 8 side pipe line 11b is closed, and the pipe line 14 that connects the pump 6 side pipe line 11a and the pipe line 13 branching from the first pipe line 10 to the tank 15 is closed.
A hydraulic transmission device characterized by being connected to.