AU2016322237A1

AU2016322237A1 - Mixer vehicle

Info

Publication number: AU2016322237A1
Application number: AU2016322237A
Authority: AU
Inventors: Shigeru Kawashima; Hiroyuki Shimizu; Kazunori Tanaka
Original assignee: KYB Corp
Current assignee: KYB Corp
Priority date: 2015-09-17
Filing date: 2016-08-10
Publication date: 2018-04-26
Also published as: WO2017047298A1; JP2017056849A; JP6093823B1

Abstract

Provided is a mixer vehicle capable of preventing ready-mixed concrete from spilling out from an opening of a mixer drum when driving up an ascending slope. A vehicle body (10) includes a mount (13). A mixer drum (20) has an opening (27) that opens to the rear end, and is rotatably mounted on the mount (13) in a forward-tilted orientation. The mixer drum (20) includes a helical drum blade (25) fixed to the inner wall surface thereof, and when the mixer drum (20) is subjected to positive rotation, ready-mixed concrete introduced therein is moved forward by the drum blade (25). A rotating device (40) causes the mixer drum (20) to rotate. An angle acquisition device (50) acquires the inclination angle of the mount (13) in the front-to-rear direction. When the inclination angle acquired by the angle acquisition device (50) becomes greater than or equal to a predetermined angle in a state where the mount (13) is in a downwardly inclined state from the front end toward the rear, a control device (70) executes a sloping road control by which the rotating device (40) increases the rotation speed of the positive rotation of the mixer drum (20).

Description

DESCRIPTION

Title of the Invention: MIXER VEHICLE Technical Field [0001] The present invention relates to a mixer vehicle. Background Art [0002] Patent Document 1 discloses a conventional mixer vehicle. This mixer vehicle includes a body, a mixer drum, and a rotating device. The body has a mount. The mixer drum has a rear end formed with an opening through which ready-mixed concrete is put into the mixer drum. The mixer drum is rotatably mounted on the mount of the body in a forward-inclined posture . The mixer drum includes two spiral drum blades fixed to an inner wall thereof. When the mixer drum is rotated forward, the ready-mixed concrete is moved forward by the drum blades. The mixer drum includes a seal pipe fixed to an inside of the drum blade located at the opening side. The rotating device rotates the mixer drum. The mixer vehicle can agitate the ready-mixed concrete by the forward rotation of the mixer drum while preventing the ready-mixed concrete from overflowing from the opening of the mixer drum by the seal pipe. Prior Art Document

Patent Documents [0003] Patent Document 1: Japanese Patent Application Publication JP H-8-40136

Summary of the Invention

Problem to Be Overcome by the Invention [0004] Even in the mixer vehicle of patent document 1, however, when a prescribed amount of ready-mixed concrete is put into the mixer drum without consideration of the posture of the mixer drum in uphill running of the mixer vehicle, if the ready-mixed concrete has a low specific gravity, the ready-mixed concrete has a possibility of overflowing from the opening of the mixer drum since the ready-mixed concrete has a large volume with respect to weight.

[0005] The present invention was made in view of the above-described circumstances in the conventional art and has an object to provide a mixer vehicle which can restrain the ready-mixed concrete from overflowing from the opening of the mixer drum when running an uphill.

Means for Overcoming the Problem [0006] A mixer vehicle in accordance with the present invention includes a body, a mixer drum, a rotating device, an angle acquisition device, and a control device. The body has a mount. The mixer drum has an opening open in its rear end so that ready-mixed concrete is put through the opening into the mixer drum. The mixer drum is rotatably mounted on the mount in a forward-inclined posture. The mixer drum has spiral drum blades fixed to its inner wall surface. The drum blades move forward the ready-mixed concrete put into the mixer drum when the mixer drum is rotated forward. The rotating device rotates the mixer drum. The angle acquisition device acquires an inclination angle of the mount in a front-back direction. The control device executes a slope running control in which the rotating device increases a rotational speed of the mixer drum in a forward rotation when the inclination angle of the mount acquired by the angle acquisition device in a state where the mount is inclined downwardly rearward from its front end is not less than a predetermined angle.

[0007] The rotating device of the mixer vehicle of the invention includes a hydraulic motor, a hydraulic pump, and a drive unit. The hydraulic motor rotates the mixer drum. The hydraulic pump can change an amount of hydraulic fluid supplied to and discharged from the hydraulic motor by changing a discharge volume of the hydraulic fluid. The drive unit drives the hydraulic pump.

[0008] The rotating device of the mixer vehicle of the invention includes a hydraulic motor, a hydraulic pump, and a drive unit. The hydraulic motor rotates the mixer drum. The hydraulic motor changes a rotational speed of the mixer drum by changing a discharge volume of hydraulic fluid. The hydraulic pump supplies and discharges the hydraulic fluid to and from the hydraulic motor. The drive unit rotates the hydraulic pump.

[0009] The control device of the mixer vehicle of the invention executes the slope driving control when an amount of ready-mixed concrete put into the mixer drum has exceeded a predetermined amount.

[0010] The angle acquisition device of the mixer vehicle of the invention includes a storage device storing map information from which an inclination angle of a road is understandable and a position specifying device specifying a travelling position. Furthermore, the angle acquisition device acquires the inclination angle of the mount in the front-back direction from the map information and the travelling position.

Brief Description of the Drawings [0011] Fig. 1 is a diagrammatic view of a mixer vehicle of first and second embodiments;

Fig. 2 is a schematic diagram of the mixer vehicle of the first and second embodiments running an uphill;

Fig. 3 is a system chart of the mixer vehicle of the first embodiment;

Fig. 4 is a flowchart illustrating a slope running control for changing a discharge volume of a hydraulic motor in the mixer vehicle of the first embodiment;

Fig. 5 is a system chart of the mixer vehicle of the second embodiment; and

Fig. 6 is a flowchart illustrating a slope running control for changing a discharge volume of a hydraulic pump in the mixer vehicle of the second embodiment.

Best Mode for Carrying Out the Invention [0012] First and second embodiments of the mixer vehicle in accordance with the invention will be described with reference to the drawings .

[0013] <First Embodiment>

As illustrated in Figs. 1 and 2, the mixer vehicle of the first embodiment includes a body 10, a mixer drum 20, a hopper 30, a chute 35, a rotating device 40, an angle acquisition device 50, a weight sensor 60, and a control device 70. The body 10 has a cabin 11, a mount 13, and an engine 80. The cabin 11 is provided at the front side of the body 10. The mount 13 is provided on the body 10 behind the cabin 11. The engine 80 is a drive unit for running the body 10 and also for rotating a hydraulic pump 43 as will be described later. The engine 80 is disposed below the cabin 11.

[0014] The mixer drum 20 has a drum body 21, a drive shaft 23, and two drum blades 25. The drum body 21 is cylindrical. The drum body 21 has an opening 27 which is open in a rear end thereof. Furthermore, the drum body 21 has a closure 29 which closes a front end thereof. The mixer drum 20 is rotatably mounted on the mount 13 in a forward-inclined posture such that the opening 27 of the drum body 21 is located at a rear end of the body 10 at an upper position and lifted to be located higher than the closure 29.

[0015] The drive shaft 23 is connected to a central part of the closure 29 of the drum body 21, extending outside the drum body 21. The drive shaft 23 extends on a center line of a rotation axis of the mixer drum 20. The drum blades 25 are fixed along an inner wall surface of the drum body 21 in a spiral manner with a predetermined space from each other. The drum blades 25 are rotated together with the drum body 21.

[0016] The hopper 30 has an inlet 31 which is open while being upwardly spread. The hopper 30 has a lower end which is open forwardly downward thereby to be formed into an outlet 33. The outlet 33 of the hopper 30 faces a central part of the opening 27 of the drum body 21. Ready-mixed concrete put through the inlet 31 of the hopper 30 is further put through the outlet 33 of the hopper 30 into the drum body 21.

[0017] The chute 35 is formed into a semicylindrical shape and elongated with an inner surface thereof being directed upward. The chute 35 has a proximal end disposed below the opening 27 of the drum body 21. The chute 35 is supported so that a distal end thereof is rotatable about the proximal end thereof in a horizontal direction and in an up-down direction. The ready-mixed concrete discharged from the opening 2 7 of the drum body 21 can be guided to a desired location by the chute 35.

[0018] The rotating device 40 includes a hydraulic motor 41, a hydraulic pump 43, and the engine 80 serving as the drive unit, as illustrated in Figs. 1 to 3 . The hydraulic motor 41 is mounted on the mount 13. The hydraulic motor 41 is coupled via a speed reducer 37 to the drive shaft 23 of the mixer drum 20. The hydraulic pump 43 is also mounted on the mount 13. The hydraulic pump 43 is coupled to a power take-off shaft 81 of the engine 80. The hydraulic pump 43 is of a two-speed type in which a discharge volume of the hydraulic fluid is switchable between two steps, large and small values. The hydraulic pump 43 includes a regulator 43A switching the discharge volume.

[0019] Each of the hydraulic pump 43 and the hydraulic motor 41 has two hydraulic fluid in- and outflow ports. The hydraulic pump 43 and the hydraulic motor 41 form a hydraulic circuit that is a closed circuit closed by flow paths 45 communicating between the in- and outflow ports of the hydraulic pump 43 and the hydraulic motor 41. Furthermore, the hydraulic circuit can circulate the hydraulic fluid in both directions by switching hydraulic fluid supply/discharge directions of the hydraulic pump 43 and the hydraulic motor 41. In other words, when the hydraulic fluid is circulated in one of the directions of the hydraulic circuit, the drum body 21 is rotated forward whereby the ready-mixed concrete is agitated while being moved forward in the drum body 21. Furthermore, when the hydraulic fluid is circulated in the other of the directions of the hydraulic circuit, the drum body 21 is rotated backward whereby the ready-mixed concrete is moved rearward in the drum body 21 thereby to be discharged from the opening 27.

[0020] In this mixer vehicle, during a normal running in which the road is not a steep uphill, that is, when a slope running control which will be described in detail later is not executed by the control device 70, the mixer drum 20 is rotated forward at a slow rotational speed to agitate the ready-mixed concrete so that characteristics of the ready-mixed concrete put into the drum body 21 do not change. Accordingly, during the normal running of the mixer vehicle, the hydraulic fluid is supplied to or discharged from the hydraulic motor 41 while the discharge volume of the hydraulic fluid of the hydraulic pump 43 is switched to the small value.

[0021] The angle acquisition device 50 is mounted on the mount 13 as illustrated in Figs. 1 and 2. The angle acquisition device 50 is a digital angle meter. The angle acquisition device 50 can acquire an inclination angle of the mount 13 in the front-back direction .

[0022] The weight sensor 60 is provided between the drum body 21 and the frame 15 rotatably supporting the drum body 21. When the ready-mixed concrete is put into the drum body 21, the weight sensor 60 detects a change in the weight, thereby being capable of detecting the weight of the put-in ready-mixed concrete.

[0023] The control device 70 is mounted on the mount 13. When the engine 80 is driven and the hydraulic pump 43 is rotated in order that the mixer drum 2 0 may be rotated forward, the control device 70 starts control of the hydraulic pump 43. Upon start of control, the control device 70 first determines whether or not the weight (input) of ready-mixed concrete put into the drum body 21 which weight has been detected by the weight sensor 60 is not less than a predetermined weight (V) (step SI) , as illustrated in Fig. 4. The predetermined weight is calculated from a maximum volume of ready-mixed concrete that does not overflow from the opening 27 of the drum body 21 even when the mixer vehicle runs a steep uphill, which weight is determined depending upon the size of the drum body 21. When the weight (input) of ready-mixed concrete detected by the weight sensor 60 is lighter than the predetermined weight (V) (the volume is smaller), the ready-mixed concrete does not overflow from the opening 27 of the drum body 21 even when the mixer vehicle runs a steep uphill. Accordingly, the control device 70 does not execute the slope running control and supplies and discharges the hydraulic fluid to and from the hydraulic motor 41 with the discharge volume of the hydraulic pump 43 switched to the small value (with a tilt angle position of the hydraulic pump 43 changed so that the discharge volume is reduced) in the same manner as in the normal running (step S5) . As a result, the mixer drum 20 is rotated forward at a slow rotational speed (step S6) and so that the mixer vehicle runs agitating the ready-mixed concrete. The control device 70 returns to step SI from step S6, continuously controlling the hydraulic pump 43 until the engine 80 is stopped so that the rotation of the hydraulic pump 43 is stopped.

[0024] Furthermore, when the weight (input) of ready-mixed concrete detected by the weight sensor 60 is not less than the predetermined weight (V) , the control device 7 0 determines whether or not an inclination angle acquired by the angle acquisition device 50 in a state where the mount 13 of the mixer vehicle is inclined downwardly rearward from the front end is not less than a predetermined angle (A) (step S2) . The predetermined angle is a maximum inclination angle of the mount 13 within a range such that the ready-mixed concrete with the predetermined weight (V) put into the drum body 21 does not overflow from the opening 27 even when the drum body 21 is inclined rearward, which angle is determined depending upon the size and the shape of the drum body 21. When the inclination angle acquired by the angle acquisition device 50 is smaller than the predetermined angle (A), that is, in the normal running, the ready-mixed concrete does not overflow from the opening 27 of the drum body 21 and accordingly, the hydraulic fluid is supplied to and discharged from the hydraulic motor 41 with the discharge volume of the hydraulic pump 4 3 switched to the small value (step S5) . As a result, the mixer drum 20 is rotated forward at a slow rotational speed (step S6) so that the mixer vehicle runs agitating the ready-mixed concrete.

[0025] Furthermore, when the inclination angle acquired by the angle acquisition device 50 is not less than the predetermined angle (A) , the control device 70 executes the slope running control with the discharge volume of the hydraulic pump 43 switched to the large value (step S3). In other words, a tilt angle position of the hydraulic pump 43 is changed so that the discharge volume of the hydraulic pump 43 is increased. When the discharge volume of the hydraulic pump 4 3 is increased, an amount of hydraulic fluid supplied to and discharged from the hydraulic motor 41 is increased with the result that the rotational speed of the hydraulic motor 41 is increased. In other words, the rotational speed of the mixer drum 20 in the forward rotation is increased (step S4). The control device 70 returns to step SI from step S4, continuously controlling the hydraulic pump 43 until the engine 80 is stopped so that the rotation of the hydraulic pump 43 is stopped.

[0026] As described above, the mixer vehicle of the first embodiment includes the body 10, the mixer drum 20, the rotating device 40, the angle acquisition device 50, and the control device 7 0 . The body 10 has the mount 13 . The mixer drum 20 has the opening 2 7 open in the rear end of drum body 21 so that the ready-mixed concrete is put through the opening 27 into the mixer drum 20. The mixer drum 20 is rotatably mounted on the mount 13 in the forward-inclined posture. The mixer drum 20 further has the spiral drum blades 25 fixed to the inner wall surface of the drum body 21, so that the drum blades 2 5 move forward the ready-mixed concrete put into the mixer drum 20 when the mixer drum 20 is rotated forward. The rotating device 40 rotates the mixer drum 20. The angle acquisition device 50 acquires an inclination angle of the mount 13 in the front-back direction. The control device 7 0 executes the slope running control in which the rotating device 40 increases a rotational speed of the mixer drum 20 in the forward rotation when the inclination angle acquired by the angle acquisition device 50 in a state where the mount 13 is inclined downwardly rearward from its front end is not less than the predetermined angle (A).

[0027] When the mixer vehicle runs an uphill, the mount 13 is inclined downwardly rearward from the front end. In this case, when the inclination angle acquired by the angle acquisition device 50 is not less than the predetermined angle (A) , the rotational speed of the mixer drum 20 in the forward rotation is increased. In other words, since the rotational speed of the mixer drum 20 in the forward rotation is increased when the mixer vehicle runs a steep uphill, the force to move forward the ready-mixed concrete in the drum body 21 of the mixer drum 20 becomes strong, with the result that the ready-mixed concrete is agitated in the drum body 21 so as to depart from the opening 27 thereby to be restrained from overflowing from the opening 27 .

[0028] Accordingly, the mixer vehicle of the first embodiment can restrain the ready-mixed concrete from overflowing from the opening 27 of the mixer drum 20 when running an uphill.

[0029] Furthermore, the rotating device 40 of the mixer vehicle of the first embodiment includes the hydraulic motor 41, the hydraulic pump 43, and the engine 80 serving as the drive unit. The hydraulic motor 41 rotates the mixer drum 20. The hydraulic pump 43 is of the two-speed type in which a discharge volume of the hydraulic fluid is switchable between two steps, large and small values, so that the hydraulic pump 43 changes an amount of the hydraulic fluid supplied to and discharged from the hydraulic motor 41 in two steps. The engine 80 drives the hydraulic pump 43. Accordingly, when the mount 13 is inclined downwardly rearward from the front end and the inclination angle acquired by the angle acquisition device 50 is not less than the predetermined angle during an uphill running of the mixer vehicle, the discharge volume of the hydraulic pump 43 can be switched to the large value, so that the rotational speed of the mixer drum 20 in the forward rotation can be increased. Thus, the rotational speed of the mixer drum 20 in the forward rotation can be increased in this mixer vehicle without increase in the power of the engine 80, so that the mixer vehicle can restrain the ready-mixed concrete from overflowing from the opening 27 of the mixer drum 20 when running an uphill.

[0030] Furthermore, the control device 70 of the mixer vehicle of the first embodiment executes the slope running control when an amount of ready-mixed concrete put into the drum body 21 exceeds the predetermined weight (V) . Thus, the control device 70 executes the slope running control only when the weight of the ready-mixed concrete put into the drum body 21 has the possibility that the ready-mixed concrete would overflow from the opening 27 of the mixer drum 20 when the mixer vehicle runs an uphill. As a result, the ready-mixed concrete can be prevented from being agitated more than necessary, whereby the change in the characteristics of the ready-mixed concrete can be suppressed.

[0031] <Second Embodiment>

As illustrated in Figs . 5 and 6, the mixer vehicle of a second embodiment differs from that of the first embodiment in that the rotating device 140 includes the hydraulic pump 143 having a constant discharge volume of hydraulic fluid, the two-speed type hydraulic motor 141 which can switch the discharge volume of hydraulic fluid between two steps, large and small values, and the regulator 141A switching the discharge volume of hydraulic fluid of the hydraulic motor 141, and that the control device 170 controls the hydraulic motor 141. Other components are same as those in the first embodiment. Identical or similar parts are labeled by the same reference symbols as those in the first embodiment, and the detailed description of these parts will be eliminated.

[0032] In this mixer vehicle, during a normal running in which the road is not a steep uphill, that is, when a slope running control which will be described in detail later is not executed by the control device 170, the mixer drum 20 is rotated forward at a slow rotational speed to agitate the ready-mixed concrete so that characteristics of the ready-mixed concrete put into the drum body 21 do not change. Accordingly, the discharge volume of the hydraulic fluid of the hydraulic motor 141 is switched to the large value during the normal running of the mixer vehicle.

[0033] The control device 170 starts the control of the hydraulic motor 141 when the engine 80 is driven and the hydraulic pump 143 is rotated to supply and discharge the hydraulic fluid to and from the hydraulic motor 141 in order that the mixer drum 20 may be rotated forward. Upon start of the control, the control device 170 first determines whether or not the weight (input) of ready-mixed concrete put into the drum body 21 which weight has been detected by the weight sensor 60 is not less than a predetermined weight (V) (step Sll), as illustrated in Fig. 6. The predetermined weight is calculated from a maximum volume of ready-mixed concrete that does not overflow from the opening 27 of the drum body 21 even when the mixer vehicle runs a steep uphill, which weight is determined depending upon the size of the drum body 21. When the weight (input) of ready-mixed concrete detected by the weight sensor 60 is lighter than the predetermined weight (V) (the volume is smaller), the ready-mixed concrete does not overflow from the opening 27 of the drum body 21 even when the mixer vehicle runs a steep uphill. Accordingly, the control device 170 does not execute the slope running control and supplies and discharges the hydraulic fluid to and from the hydraulic motor 141 with the discharge volume of the hydraulic motor 141 switched to the large value (with a tilt angle position of the hydraulic motor 141 changed so that the discharge volume is increased) in the same manner as in the normal running (step S15) . As a result, the mixer drum 20 is rotated forward at a slow rotational speed (step S16) so that the mixer vehicle runs agitating the ready-mixed concrete. The control device 170 returns to step Sll from step SI6, continuously controlling the hydraulic motor 141 until the engine 80 is stopped so that the rotation of the hydraulic motor 141 is stopped.

[0034] Furthermore, when the weight (input) of ready-mixed concrete detected by the weight sensor 60 is not less than the predetermined weight (V) , the control device 170 determines whether or not an inclination angle acguired by the angle acquisition device 50 in a state where the mount 13 of the mixer vehicle is inclined downwardly rearward from the front end is not less than a predetermined angle (A) (step S12) . The predetermined angle is a maximum inclination angle of the mount 13 within a range such that the ready-mixed concrete put into the drum body 21 does not overflow from the opening 27 even when the drum body 21 is inclined rearward, which angle is determined depending upon the size and the shape of the drum body 21. When the inclination angle acquired by the angle acquisition device 50 is smaller than the predetermined angle (A) , that is, in the normal running, the ready-mixed concrete does not overflow from the opening 27 of the drum body 21 and accordingly, the discharge volume of the hydraulic motor 141 is switched to the large value (step S15). As a result, the mixer drum 20 is rotated forward at a slow rotational speed (step S16) so that the mixer vehicle runs agitating the ready-mixed concrete.

[0035] Furthermore, when the inclination angle acquired by the angle acquisition device 50 is not less than the predetermined angle (A), the control device 170 executes the slope running control with the discharge volume of the hydraulic motor 141 switched to the small value (step S13) . In other words, the tilt angle position of the hydraulic motor 141 is changed so that the discharge volume of the hydraulic motor 141 is reduced. When the discharge volume of the hydraulic motor 141 is reduced, the hydraulic motor 141 is rotated with a smaller amount of hydraulic fluid supplied or discharged with the result that the rotational speed of the hydraulic motor 141 is increased. In other words, the rotational speed of the mixer drum 20 in the forward rotation is increased (step S14). The control device 170 returns to step Sll from step S14, continuously controlling the hydraulic motor 141 until the engine 80 is stopped so that the rotation of the hydraulic motor 141 is stopped.

[0036] As described above, when the inclination angle acquired by the angle acquisition device 50 in a state where the mount 13 is inclined downwardly rearward from the front end is not less than the predetermined angle, the control device 170 in the mixer vehicle of the second embodiment, too, executes the slope running control in which the rotating device 140 increases a rotational speed of the mixer drum 20 in the forward rotation. Accordingly, in this mixer vehicle, too, since the rotational speed of the mixer drum 20 in the forward rotation is increased when the mixer vehicle runs a steep uphill, the force to move forward the ready-mixed concrete in the drum body 21 of the mixer drum 20 becomes strong, with the result that the ready-mixed concrete is agitated in the drum body 21 so as to depart from the opening 27 thereby to be restrained from overflowing from the opening 27 .

[0037] Accordingly, the mixer vehicle of the second embodiment can also restrain the ready-mixed concrete from overflowing from the opening 27 of the mixer drum 20 when running an uphill.

[0038] Furthermore, the rotating device 140 of the mixer vehicle of the second embodiment includes the hydraulic motor 141 which is of the two-speed type in which a discharge volume of hydraulic fluid is switchable between two steps, large and small values, thereby being capable of changing the rotational speed of the mixer drum 20. Accordingly, when the mount 13 is inclined downwardly rearward from the front end and the inclination angle acquired by the angle acquisition device 50 is not less than the predetermined angle during an uphill running of the mixer vehicle, the discharge volume of the hydraulic motor 141 can be switched to the small value, so that the rotational speed of the mixer drum 20 in the forward rotation can be increased. Thus, the rotational speed of the mixer drum 20 in the forward rotation can be increased in this mixer vehicle without increasing the amount of the hydraulic fluid which the hydraulic pump 143 supplies to and discharges from the hydraulic motor 141, so that the mixer vehicle can restrain the ready-mixed concrete from overflowing from the opening 27 of the mixer drum 20 when running an uphill.

[0039] The present invention should not be limited to the first and the second embodiments described above with reference to the drawings, but the technical scope of the invention encompasses the following embodiments, for example. (1) Although the angle acquisition device is the digital angle meter in the first and second embodiments, the angle acquisition device may include a storage device storing map information and a position specifying device which specifies a travelling position of the mixer vehicle (for example, a device using a global positioning system, GPS) to acquire an inclination angle of the mount in the front-back direction from the map information and the travelling position. In other words, a running direction is grasped from the travelling position specified by the position specifying device . The inclination angle of a road may be acquired by determining whether or not the mixer vehicle is running an uphill or a downhill, on the basis of a road where the mixer vehicle is running and the changes in the elevation data along the direction in which the mixer vehicle is running. Alternatively, map information directly involving data of an inclination angle of the road may be stored in the storage device . In this case, since an inclination angle of the mount of the mixer vehicle equals an inclination angle of the road where the mixer vehicle is running, the inclination angle of the mount of the mixer vehicle can be acguired, with the result that the slope running control can accurately be executed. Conseguently, the mixer vehicle can restrain the ready-mixed concrete from overflowing from the opening of the mixer drum when running an uphill. (2) Although the weight sensor is provided to grasp an amount of ready-mixed concrete by the weight in the first and second embodiments, a sensor may be provided to measure a cubic volume of ready-mixed concrete in the drum body in order that an amount of ready-mixed concrete may be grasped by the cubic volume. (3) Although the weight sensor is provided on the mixer vehicle to grasp an amount of ready-mixed concrete put into the drum body in the first and second embodiments, the mixer vehicle may not be provided with a weight sensor or the like to grasp an amount of ready-mixed concrete. In this case, an amount of ready-mixed concrete (weight or cubic volume) measured at the equipment side upon put of the ready-mixed concrete into the drum body may be input to the control device to be used. (4) Although, in the first and second embodiments, the rotating device includes the two-speed hydraulic pump or motor both of which can switch the discharge volume between two steps, large or small values, a hydraulic pump or a hydraulic motor which can continuously change the discharge volume may be used. In this case, the control device may continuously change the discharge volume of the hydraulic pump or the hydraulic motor according to an input of ready-mixed concrete or an inclination angle of the mount. (5) Although the rotating device for rotating the mixer drum comprises a hydraulic power unit having the hydraulic motor and the hydraulic pump in the first and second embodiments, the mixer drum may electrically be rotated. (6) Although the drive unit for rotating the hydraulic pump is the engine driving the body in the first and second embodiments, the hydraulic pump may be rotated by an engine other than that driving the body or an electric motor . In this case, the hydraulic pump can be rotated to rotate the mixer drum even during stop of the engine. (7) Although the rotational speed of the mixer drum is increased by increasing the discharge volume of the hydraulic pump or reducing the discharge volume of the hydraulic motor in the first or second embodiment, the rotational speed of the mixer drum may be increased by increasing the rotational speed of the engine (drive unit).

Explanation of Reference Symbols [0040] 10 ... body, 13 ... mount, 20 ... mixer drum, 25 ... drum blade, 27 ... opening, 40 ... rotating device, 41, 141 ... hydraulic motor, 43, 143 ... hydraulic pump, 50 ... angle acquisition device, 70, 170 ... control device, 80 ... engine (drive unit) .

Claims

1. A mixer vehicle comprising: a body having a mount; a mixer drum having an opening open in a rear end thereof so that ready-mixed concrete is put therethrough into the mixer drum, the mixer drum being rotatably mounted on the mount in a forward-inclined posture, the mixer drum having spiral drum blades fixed to an inner wall surface thereof, the drum blades moving forward the ready-mixed concrete put into the mixer drum when the mixer drum is rotated forward; a rotating device rotating the mixer drum; an angle acguisition device acguiring an inclination angle of the mount in a front-back direction; and a control device executing a slope running control in which the rotating device increases a rotational speed of the mixer drum in a forward rotation when the inclination angle of the mount acquired by the angle acquisition device in a state where the mount is inclined downwardly rearward from a front end thereof is not less than a predetermined angle.

2. The mixer vehicle according to claim 1, wherein the rotating device includes a hydraulic motor rotating the mixer drum, a hydraulic pump changing an amount of hydraulic fluid supplied to and discharged from the hydraulic motor by changing a discharge volume of the hydraulic fluid, and a drive unit rotating the hydraulic pump.

3. The mixer vehicle according to claim 1, wherein the rotating device includes a hydraulic motor rotating the mixer drum and changing a rotational speed of the mixer drum by changing a discharge volume of hydraulic fluid, a hydraulic pump supplying and discharging the hydraulic fluid to and from the hydraulic motor, and a drive unit rotating the hydraulic pump.

4. The mixer vehicle according to any one of claims 1 to 3, wherein the control device executes the slope driving control when an amount of ready-mixed concrete put into the mixer drum has exceeded a predetermined amount.

5. The mixer vehicle according to any one of claims 1 to 3, wherein the angle acquisition device includes a storage device storing map information from which an inclination angle of a road is understandable and a position specifying device specifying a travelling position, and the angle acquisition device acquires the inclination angle of the mount in the front-back direction from the map information and the travelling position.