JPS6041532A - Revolution controlling device of mixer drum - Google Patents

Abstract

PURPOSE:To reduce the number of revolutions when the drum is rotated at a high speed, to save the consumption of fuel, and to reduce the noise by enlarging the size of a hydraulic pump, and conversely reducing the size of a hydraulic motor when the drum of a mixer is rotated with the hydraulic motor. CONSTITUTION:The drum 1 of a truck mixer agitator of raw concrete is rotated by a small-capacity hydraulic motor 2 which is rotated normally and reversely at an increased and a reduced speed. The hydraulic motor 2 is rotated by a compressed oil supplied through passages 5 and 6 from a large-capacity variable displacement hydraulic pump 4, and the hydraulic pump 4 is rotated by an engine 7. Pressure sensors 14 and 15 are provided to the passages 5 and 6 as an oil pressure detecting means, and the capacity of the hydraulic pump 4 can be controlled by the sensors. When the number of revolutions is made larger than the number to knead the raw concrete during the washing period of the drum 1, the noise caused by the fuel for the engine of the hydraulic pump 4 and the rotation of the engine can be reduced because the capacity of the hydraulic motor 2 is small and the capacity of the hydraulic pump 4 is large.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a drum rotating device for a mixer.

Conventionally, in mixer drum rotation devices, the hydraulic motor that rotates the drum is driven by a hydraulic pump that is driven by an engine. This is not much of a problem as the number should be around idling speed (600 rpm), but if the drum rotation speed is 3 to 3 rpm, such as when cleaning the drum, the engine speed should be increased to a maximum of about 230 rpm. This caused problems in terms of fuel consumption and noise.

The present invention has been made in view of these points, and the hydraulic pump is made larger compared to the conventional case to increase the discharge capacity, while the hydraulic motor is conversely made smaller and configured so that it can rotate with a small capacity. It is an object of the present invention to provide a drum rotation control device for a mixer that can lower the engine rotation speed when the drum rotates at high speeds such as during cleaning, thereby achieving fuel savings and noise reduction. This is the main purpose.

In order to achieve the above-mentioned object, the present invention includes a drum rotatably mounted on a base, a drive means for rotating the drum in forward and backward directions and increasing and decelerating it, and a control means for controlling the drive means. In the mixer, the drive means includes a large-capacity variable-capacity cedar hydraulic pump and a small-capacity hydraulic motor, and the control means has a hydraulic pressure detection section, and the hydraulic pressure detected by the hydraulic pressure detection section drives the hydraulic pump. The feature is that the capacity is controlled.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated along drawing about the Example applied to a mixer truck.

In Fig. 1 showing the overall configuration of a drum rotation control device for a mixer truck, 1 is a drum rotatably mounted on a base (not shown), and a small-capacity hydraulic motor 2 rotates the drum 1 in forward and reverse directions. And the rotation is increased/decelerated. Said hydraulic motor 2
The hydraulic pump 4 is rotated forward or reverse by pressure oil that is selectively supplied through passages 5 and 6 from a large-capacity variable displacement hydraulic pump 4. It is mechanically linked to the engine 7 and rotated by the engine 7.

A tilting lever 8 is linked to a servo valve (not shown) for controlling the hydraulic pump 4, and the tilting lever 8 is swung by a drive motor 9, thereby controlling the hydraulic pressure. The rotation of the pump 4 is controlled.

10 is the throttle lever of the engine 7, and the drive motor 1
1, which controls the engine speed.

Both drive motors 9 and 11 are linked via a drive circuit 12 to an information processing means 13 (microconbeater) as a control means.

Reference numerals 14 and 15 indicate pressure sensors as oil pressure detection units, which are linked to the information processing means 13 via a sensor input circuit 16. In addition, 17 is a first
A rotation speed sensor 18 is a second rotation speed sensor that detects the engine rotation speed, and both rotation speed sensors 17 and 18 are linked to the information processing means 13 via a sensor input circuit 19, respectively.

Reference numerals 20 and 21 indicate operating units provided in the driver's cab and outside, respectively, and the rotation of the drum 1 can be controlled by rotating knobs 20a and 20b. Reference numerals 22 and 23 are rotational speed display units provided in the driver's cab and outside, respectively, and 24 is an oil reservoir.

The discharge amount of the hydraulic pump 4 is 9.0 for the conventional type. l
i'cc/rev while //j? , Otsu CC/
r e v, and the discharge amount of the hydraulic motor 2 is 2.2 c/re for the conventional type.
v, JJ, 3cc/rev is smaller, and as a result, the discharge amount of the hydraulic pump 4 is larger than that of the hydraulic motor 2, and the rotational speed of the hydraulic pump 4 and therefore the rotational speed of the engine 7 is smaller. , can be lower than the conventional type.

With the above configuration, the hydraulic pump 4 is connected to the engine 7.
is rotated, pressure oil is supplied to the hydraulic motor 2 by the hydraulic pump 4, and the drum 1 is rotated. At that time, mainly when driving (during crosstalk work), the rotation speed setting signal from the operation unit 20 inside the driver's cab and the drum rotation speed signal from the first rotation speed sensor 17 are input to the information processing device 16, and then The drive motor 9 is activated by the output signal of the information processing device 16.
, and as a result, the hydraulic pump 4 is controlled.

On the other hand, when stopped (mainly during ejection work), the rotation speed setting signal is sent to the information processing device 13 by rotating the knob 20a or 21a of the operation unit 20 or 21 in the reverse direction (in the forward direction in case of crosstalk) to the desired position. and the information processing device 13 controls both drive motors 9.1 according to the setting signal.
1 is controlled.

Further, when the operating pressure is detected by the pressure sensors 14 and 15 and the detected value is higher than the set value, the rotation of the tilting lever 8 of the hydraulic pump 4 is restricted to suppress the pump discharge amount, and the drum While the rotational speed is lowered, if the detected value is lower than the set value, the tilting lever 8 is moved significantly to increase the pump discharge amount while the engine speed remains low, and the drum rotational speed is increased.

Therefore, when there is a mix of lines in the Namukureet, the torque is large but the rotational speed of the drum 1 is low at about 2 to J rpm, so there is no need to increase the engine rotational speed, and the drum 1 can be rotated with low engine noise. I can do it.

On the other hand, when cleaning the drum, it is necessary to rotate the drum 1 at about 3 to 3 rpm, but compared to the conventional case, the hydraulic motor 2 is small in capacity and the hydraulic pump 4 is large in capacity.
Since it is not necessary to increase the rotation speed of the hydraulic pump 4 so that the rotation speed of the engine 7 does not exceed L, there is no need to increase the rotation speed of the engine 7.

That is, the discharge of the hydraulic pump 4 can be adjusted to a predetermined value by simply tilting the tilting Lenoy 8 while the engine speed remains low. Moreover, as mentioned above, the engine speed is detected by the pressure sensor 14.15 and is controlled accordingly to be as low as possible, and the engine speed is slightly higher than the speed that causes engine stalling. Therefore, compared to the conventional case, the Ennon Ao-on becomes smaller.

The operating range of the tilting lever 8 is as shown in FIG.
The discharge amount of the hydraulic pump 4 is adjusted by changing the angle θ] during cleaning and the angle θ2 during kneading.

Since the present invention has been developed as described above, the engine speed does not become too high regardless of whether the fresh concrete is being mixed or discharged or the drum is being cleaned, making it possible to save fuel and reduce noise. "Practical" 1
Has excellent effects.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is an overall configuration diagram of a mixer drum rotation control device, and FIG. 2 is an explanatory diagram of the operating range of a tilting lever. 1...Drum, 2...Hydraulic motor, 4...
...Variable displacement hydraulic pump, 16... Information processing means, 14゜15... Pressure sensor

Claims (1)

[Claims] (1) A drum is rotatably mounted on a base, and the drum is rotated in forward and backward directions and is increased and decelerated. and drive means. In the mixer comprising a control means for controlling the drive means, the drive means is constituted by a large-capacity variable displacement forged hydraulic pump and a small-capacity hydraulic motor, and the control means has a hydraulic pressure detection section. A drum rotation control device for a mixer, characterized in that the capacity of the hydraulic pump is controlled by the oil pressure detected by the oil pressure detection section.