JPH0714053Y2 - Traveling equipment for transport vehicles - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a traveling device for a carrier vehicle that transports cargo in factories, warehouses, and the like.

[Conventional technology]

In a transport vehicle in which an electric motor drives a hydraulic pump to rotate a hydraulic motor to drive driving wheels, the vehicle starts when an operating valve provided in a circuit between the hydraulic pump and the hydraulic motor is operated. When the actuating valve is neutralized during traveling, the hydraulic pump and the hydraulic motor are disconnected, and the hydraulic motor is rotated by the traveling inertia of the transport vehicle.

At this time, the hydraulic fluid flowing through the hydraulic motor returns to the hydraulic motor again via the brake valve, so the braking force can be changed by adjusting the set pressure of the brake valve.

However, since the required pressure of the hydraulic motor is determined by the required torque of the hydraulic motor when the transport vehicle is traveling, the set pressure of the brake valve cannot be set lower than the required pressure of the hydraulic motor.

[Problems to be solved by the device]

Normally, the braking shock of the valve that stops the running vehicle decreases as the set value of the brake valve decreases and the braking force decreases. However, for the above reason, the set value of the brake valve has a lower limit, and it is not only the pressure adjustment of the brake valve that further reduces the braking shock. Further, if the operating valve is opened until the traveling is stopped, the moment of inertia of the electric motor is large, and the hydraulic pump is in a driven state, which does not easily stop.

Then, this invention aims at providing the traveling apparatus of the conveyance vehicle which can reduce a braking shock irrespective of the pressure adjustment of a brake valve.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides a traveling apparatus for a transport vehicle in which a hydraulic pump that rotates a hydraulic motor for driving wheels is driven by a transmission motor. A hydraulic circuit for the working auxiliary devices and the like, and a cylinder for operating the working auxiliary devices,
A relief valve having a valve opening set pressure lower than the pressure of the working oil supplied to the hydraulic circuit for the drive wheels is provided to shut off the electric motor power during braking and operate the hydraulic motor for the drive wheels. A braking means for opening the valve and the operating valve of the cylinder is provided.

[Action]

With this configuration, when the electric motor power is cut off during braking, the operating valve of the hydraulic motor for the drive wheels is open, so the moment of inertia of the electric motor is large and the hydraulic pump is still driven. The hydraulic pump for working auxiliary devices etc. is also driven via the electric motor, but by opening the work valve of the cylinder for working auxiliary devices etc.,
When the cylinder is actuated to the stopper contact side, the relief valve of the hydraulic circuit such as auxiliary equipment for work works to create an appropriate load against the moment of inertia of the electric motor, and the transport vehicle slows down and the shock during braking is large. Is alleviated.

〔Example〕

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

FIG. 1 shows a hydraulic circuit 1 of a carrier vehicle. In the hydraulic circuit 1, a hydraulic circuit 2 for traveling and a hydraulic circuit 3 for raising and lowering a boom of a crane mounted as work auxiliary equipment are provided. It is installed side by side.

The traveling hydraulic circuit 2 includes a hydraulic pump 5 driven by an electric motor 4, hydraulic motors 6 and 7 rotated by hydraulic oil supplied from the hydraulic pump 5, the hydraulic pump 5 and the hydraulic motors 6 and 7. An operation valve 8 and a brake valve 9 for supplying and shutting off hydraulic oil are provided between the and.

The hydraulic circuit 3 for raising and lowering the boom includes a hydraulic pump 5 for traveling.
Hydraulic pump 10 installed in parallel with the electric motor 4 coaxially with
Cylinders 11 and 12 operated by hydraulic oil supplied from the hydraulic pump 10, operating valves 13 and 14 for expanding and contracting the cylinders 11 and 12, respectively, and a relief valve 15 are provided. The valve opening set pressure is set lower than the pressure of the hydraulic oil supplied to the traveling hydraulic circuit 2.

The electric motor 4 is driven by a battery 16, and a main switch 17 is provided between the battery 16 and the transmission motor 4.

Further, FIG. 2 is a flowchart of the control means of the transport vehicle,
In a traveling state in which the traveling operation valve 8 is open, normally, the cylinders 11 and 12 for raising and lowering the boom of the crane are contracted and are located on the end side.

If a stop operation is performed from this state using a foot switch, etc., the main switch 17 is turned off and the cylinder 1
The operating valves 13 and 14 of the cylinders 11 and 12 are opened so that the valves 1 and 12 can be further moved to the end side.

When the main switch 17 is turned off, the rotational inertia of the electric motor 4 remains, so that the boom pump hydraulic pump 10 is driven and the operation valves 13 and 14 of the cylinders 11 and 12 are opened. Hydraulic oil is supplied to the cylinders 11,
12 tries to move further to the end side, but cylinders 11 and 12
Is already on the end side, the relief valve 15
Opens.

Since the relief valve 15 has a valve opening set pressure set lower than the pressure of the hydraulic oil supplied to the traveling hydraulic circuit 2, the relief valve 15 operates in cooperation with the traveling inertia of the transport vehicle. The load is moderate against the moment of inertia, and the carrier is forced to decelerate.

Then, the transport vehicle is decelerated to some extent, and in this embodiment, it stops after 0.6 seconds has elapsed due to the timer setting. Next, the operation valves 13 and 14 of the cylinders 11 and 12 are closed.

Then, in this embodiment, when 0.2 seconds has elapsed due to the timer setting, the traveling operating valve 8 is closed, the flow of hydraulic oil between the hydraulic pump 5 and the hydraulic motors 6 and 7 is shut off, and the transport vehicle is completely stopped. To do.

Therefore, a deceleration time is provided from the stop operation to the stop of the transport vehicle, so that the shock at the time of stop is significantly reduced and the braking distance is shortened.

Further, since the braking shock can be reduced and the vehicle can be stopped without operating the brake valve 9, the present invention can be applied to a vehicle having a traveling hydraulic circuit without a brake valve.

Further, the number of hydraulic motors is not limited to the above embodiment, and can be applied to one vehicle or three or more vehicles.
For example, a cylinder such as an outrigger or a steering mechanism may be used as the working accessory.

[Effect of device]

As described above, the traveling device for a transport vehicle according to the present invention is provided with an electric motor that drives a hydraulic pump that rotates a hydraulic motor for driving wheels, and a hydraulic pump that operates auxiliary equipment for work and the like. In the hydraulic circuit of the auxiliary devices for work, etc., a cylinder for operating the auxiliary devices for work, etc., and a relief valve whose opening set pressure is lower than the pressure of the hydraulic oil supplied to the hydraulic circuit for the drive wheels are provided. At the time of braking, the power supply to the electric motor is cut off, and the braking means for opening the operation valve of the hydraulic motor for the drive wheels and the operation valve of the cylinder are provided. Since the operating valve of the hydraulic motor for the drive wheels is open, the hydraulic inertia for the drive wheels drives the hydraulic pump for the drive wheels due to the traveling inertia of the transport vehicle and the moment of inertia of the electric motor. vessel The hydraulic pumps for equal operation are also driven, but when the work valve of the cylinder such as the work auxiliary equipment is opened and the cylinder is operated toward the stopper contact side, the relief valve of the hydraulic circuit for the work auxiliary equipment etc. is opened. This acts as an appropriate load on the traveling inertia of the transport vehicle, and the transport vehicle decelerates and the shock during braking is significantly reduced.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a traveling device for a carrier vehicle, and FIG. 2 is a flowchart of braking means. 1 ... hydraulic circuit, 2 ... hydraulic circuit for traveling, 3 ... hydraulic circuit for raising and lowering boom, 4 ... electric motor, 5 ... hydraulic pump, 6,
7 ... hydraulic motor, 8 ... traveling operating valve, 10 ... hydraulic pump, 11,12 ... cylinder, 13,14 ... cylinder operating valve, 15
… Relief valve, 16… Battery, 17… Main switch

Claims (1)

[Scope of utility model registration request] 1. A traveling apparatus for a carrier vehicle, comprising an electric motor for driving a hydraulic pump for rotating a hydraulic motor for driving wheels, wherein the electric motor is provided with a hydraulic pump for actuating auxiliary devices for working. A hydraulic circuit for working accessories, etc. is provided with a cylinder for operating the working accessories, etc., and a relief valve whose opening pressure is lower than the pressure of hydraulic oil supplied to the driving wheel hydraulic circuit. A traveling device for a transport vehicle, which is provided with a braking means that shuts off the electric power of the electric motor during braking and opens the operating valve of the hydraulic motor for the drive wheels and the operating valve of the cylinder.