JPH07909Y2 - Wheel-type hydraulically driven vehicle traction force display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a traction force display device for a vehicle equipped with a wheel type hydraulically driven traveling device such as a wheel loader.

B. Prior Art This type of vehicle includes a hydraulic pump driven by a prime mover, a hydraulic motor driven by this hydraulic pump, and a transmission that shifts the output of the hydraulic motor to, for example, two stages and transmits it to the wheels. The driver determines the driving force required for the vehicle and selects the gear ratio.

C. Problems to be solved by the device However, in this type of vehicle, since the actual tire driving force, that is, the traction force is not displayed, it is difficult to understand how much traction force is generated, and tires are unnecessarily Various troubles were caused by slipping or overloading the drive system such as the axle.

An object of the present invention is to provide a traction force display device that solves such a problem by displaying the traction force at the driver's seat.

D. Means for Solving the Problems The present invention relates to a wheel type hydraulic drive including a hydraulic circuit having a hydraulic pump and a traveling hydraulic motor, and a transmission that decelerates the output of the traveling hydraulic motor to drive wheels. It is applied to a vehicle traction force display device, and a detector for detecting the supply pressure value of a traveling hydraulic motor and a supply pressure value detected by the detector provided in the driver's seat are converted into a vehicle traction force value. The above-described object can be achieved by including a display meter for displaying.

E. Action The supply pressure value of the hydraulic motor is converted into the traction force value of the vehicle and displayed on the display.

F. Example-First Example-The first example will be described with reference to FIGS. 1 and 2. The traction force display device according to the present invention is configured, for example, as shown in FIG. 1, and is mounted on, for example, the wheel loader shown in FIG.

The hydraulic pump 2 is driven by the output of the prime mover 1, and the output shaft of a hydraulic motor 3 connected to the hydraulic pump 2 in a closed circuit is connected to the transmission 4. The transmission 4 shifts the input rotation in two stages and drives the front axle 5 and the rear axle 6, whereby the tires (wheels) 7 are rotationally driven.

Pipe lines 8a, 8b connected to the inlet / outlet port of the hydraulic motor 3 are connected via a shuttle valve 9, and the shuttle valve 9 is connected via a pipe line 10 to a Bourdon tube type traction force installed in the driver's seat. Indicator 11 is connected. As shown in FIG. 3, the indicator 11 shows a traction scale Low for the low speed stage and a scale High for the high speed stage. In FIG. 2, 13 indicates a bucket.

In the traction force display device thus configured, the pressure oil (supply pressure) on the high pressure side of the hydraulic motor 3 reaches the indicator 11 through the conduit 10 and the indicator needle 11a is deformed by the deformation of the Bourdon tube (not shown). Shake according to pressure. The pressure of the hydraulic circuit 12 shown in FIG. 1 is the same regardless of whether the transmission is in the low speed stage or the high speed stage, and the indicator 11 swings at full scale at the maximum pressure of the hydraulic circuit 12. Therefore, the driver reads the two scales Low and High of the display 11 according to the set variable speed stage to check the actual traction force.

-Second Embodiment- In the second embodiment shown in Fig. 4, the deflection angle of the indicating needle 21a of the Bourdon tube type traction force indicator 21 is changed according to the gear ratio,
The scale of the display 21 is displayed continuously. Only points different from FIG. 1 will be described.

An electromagnetic valve 22 is provided between the pipeline 10 for taking out the pressure of the hydraulic circuit 12 from the shuttle valve 9 and the indicator 21. This solenoid valve 22 is switched according to the switching position of the switch 23 that responds to the change of the gear ratio. The position switches to. A pipe line 24a connecting the solenoid valve 22 and the indicator 21 is for a low speed stage and a pipe line 24b is for a high speed stage, and is connected to two Bourdon tubes (not shown) in the indicator 21 respectively. The Bourdon tube for the high speed stage is designed so that the indicator needle 21a is swung from the zero position to the center (approximately 1/2 full scale) according to the pressure 0 to the maximum of the hydraulic circuit 12, and the Bourdon tube for the low speed stage is , When the hydraulic pressure is 0 to the highest, the indicator needle 21a is swung from the zero position to the full scale position. And display total 2
At 1, the traction force scale 21b is continuously displayed from zero to the maximum value.

In the traction force display device thus configured, the transmission 4
Switch is set to low
The solenoid valve 22 is in the position "A" in the figure. When pressure rises in the hydraulic circuit 12, pressure oil is guided to the Bourdon tube for the low speed stage in the indicator 21 via the shuttle valve 9, the pipe line 10, the solenoid valve 22 and the pipe line 24a, and the indicator needle 21a moves. Shake according to the deformation. When the hydraulic circuit 12 reaches the maximum pressure, the indicating needle 21a swings at full scale and indicates the maximum traction force obtained at the low speed stage. Similarly, when the high speed stage is selected, the switch
23 becomes High position and solenoid valve 22 switches to "B" position. As a result, the pressure oil is guided to the Bourdon tube for the high speed stage and the indicator needle 21a swings. When the pressure oil reaches the maximum value, the indicator needle 21a swings by about 1/2 full scale to indicate the maximum traction force obtained at the high speed stage.

The two-stage type indicator 21 is not limited to the above embodiment, and may be constituted by one Bourdon tube. In this case, when the high speed stage is selected, the pressure introduced from the pipe line 24a is reduced. It is necessary to shake the Bourdon tube with oil and to provide a stopper mechanism so that the indicator needle 21a does not shake more than approximately 1/2 full scale under the maximum pressure.

Further, the pressure sensor detects the supply pressure of the hydraulic motor 3,
The traction force may be calculated from the detected value and the shift speed, and the traction force may be displayed in analog or digital form on the display.

G. Effect of the Invention According to the present invention, since the traction force of the vehicle is displayed in the driver's seat, the durability of the vehicle is improved without overloading the drive system such as the axle. In addition, unnecessary slip of the tire can be prevented and tire wear is reduced.

[Brief description of drawings]

1 and 4 are block diagrams showing a second embodiment of the present invention,
FIG. 2 is a side view of a wheel loader equipped with a traction force display device, and FIG. 3 is a front view of a display meter in the first embodiment. 2: Hydraulic pump, 3: Hydraulic motor 4: Transmission, 9: Shuttle valve 11: Indicator, 12: Hydraulic circuit

Claims (1)

[Scope of utility model registration request] 1. A traction force display device for a wheel type hydraulically driven vehicle, comprising: a hydraulic circuit having a hydraulic pump and a traveling hydraulic motor; and a transmission for decelerating the output of the traveling hydraulic motor to drive wheels. It is provided with a detector for detecting the supply pressure value of the traveling hydraulic motor, and an indicator provided in the driver's seat for converting the supply pressure value detected by the detector into a traction force value of the vehicle for display. A traction force display device for wheel-type hydraulically driven vehicles.