JP2578599Y2 - Engine accelerator control device for hydraulic crane - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hydraulic crane driven by hydraulic pressure generated by a hydraulic pump driven by a truck engine, the base of which is mounted on a chassis frame between a truck cab and a cargo bed. , An engine accelerator control device.

[0002]

2. Description of the Related Art A conventional engine accelerator control device for a hydraulic crane will be described with reference to FIGS. First, this type of hydraulic crane will be described. As shown in FIG. 3, the hydraulic crane has its base 1 mounted on a chassis frame A between a truck cab and a cargo bed (both not shown). Installed. A turning post having a telescopic boom mounted thereon so as to be able to be driven up and down is pivotally mounted on the base 1, and a winch is mounted on the turning post or telescopic boom. Therefore, the illustration is omitted.

FIG. 4 shows a hydraulic circuit of a hydraulic crane. In FIG. 4, reference numerals 2, 3, 4, and 5 denote a turning motor that drives the turning post to turn, an up / down cylinder that drives the telescopic boom up and down, a telescopic cylinder that drives the telescopic boom to extend and retract, and a winch motor that drives the winch. . These hydraulic actuators 2 to 5 are driven using a hydraulic pressure generated by a hydraulic pump 7 driven by an engine 6 of a truck to which a hydraulic crane is attached, as a driving hydraulic source. And each hydraulic actuator 2
The drive control of (5) to (5) is controlled by four-way three-position hydraulic switching valves 8 to 11, respectively. Each of the hydraulic switching valves 8 to 11 is configured as a center position P port carry over type in which the P port carries over at the center position. At a neutral position of each of the hydraulic switching valves 8 to 11, the pressure oil from the pump oil passage 12 of the hydraulic pump 7 flows over the hydraulic switching valves 8 to 11 sequentially to the tank 13. Reference numeral 14 denotes a relief valve interposed between the pump oil passage 12 and the tank 13.

As shown in FIG. 3, the hydraulic switching valves 8 to 11 are mounted on a base 1 of a hydraulic crane in a vertically overlapping manner. The operation of each hydraulic switching valve is performed by a pair of left and right operating levers provided at the left and right ends of the base 1 corresponding to the corresponding hydraulic switching valve. 3, a pair of right and left operation levers for operating the hydraulic switching valve 8 are indicated by 8a and 8b, a pair of right and left operating levers for operating the hydraulic switching valve 9 are indicated by 9a and 9b, and the hydraulic switching valve 1
0 and 10a and 10
b, a pair of right and left operation levers for operating the hydraulic switching valve 11 is indicated by 11a and 10b. The operation levers 8a to 11a located on the right side of the base 1 are mounted so as to be capable of swinging forward and backward (back and forth) with the vertical support shaft 15 mounted on the base 1 side as a fulcrum. It is connected to the spool of the hydraulic switching valve. The operation levers 8b to 11b located on the left side of the base are mounted so as to be capable of swinging forward and backward (back and forth) with the vertical support shaft 16 mounted on the base 1 as a fulcrum. Lever 8
a to 11a are connected to each other via connecting rods 8c to 11c.

Each of the hydraulic switching valves 8 to 11, the corresponding operating levers 8a to 11a, 8b to 11b, and the connecting rods 8c to 8c
11c are all the same, and therefore, typically, the hydraulic switching valve 11, the operating levers 11a and 11b, and the connecting rod 1c.
The connection relationship 1c will be described with reference to FIG.

In FIG. 5, an operating lever 11a is pivotally connected at its base end 11d to a vertical support shaft 15 located near the hydraulic control valve 11 so as to be tiltable forward and backward (up and down in the figure). ing. An operation point 11e near the vertical support shaft 15 in the base end 11d is connected to a spool of the hydraulic switching valve 11, and the operating lever 11a is tilted from the neutral position in the forward / reverse direction to operate the hydraulic switching valve 11. Switching operation can be performed in the forward and reverse directions. The proximal end 11d of the operation lever 11a has an arm 11f extending downward in the figure. On the other hand, the operation lever 11b
Has a base end 11g pivotally connected to a vertical support shaft 16 so as to be capable of tilting forward and backward (lower and upper in the figure). An arm 11 extending upward in the figure is provided at the base end 11g.
h is attached. The connecting rods 11c are connected between the distal ends of the base ends 11d and 11g of the operation levers 11a and 11b, and when the operation lever 11b is tilted from the neutral position in the forward and reverse directions, the hydraulic switching valve 11 is moved in the forward and reverse directions. Can be switched.

As described above, the hydraulic crane is
Forward and reverse tiltable operation levers 8a to 11a, 8 for switching control of hydraulic switching valves 8 to 11 for controlling the driving thereof
b to 11b are provided. In this type of hydraulic crane, each operating lever 8a of the hydraulic switching valves 8 to 11 is provided.
11a or 8b to 11b, the accelerator lever 6a for adjusting the governor of the engine 6 is increased or decreased in response to the tilting and returning movement of the operating lever in the forward / reverse tilting region of a predetermined amount or more from the neutral position. And an engine accelerator control device B for performing the operation. The accelerator lever 6a for controlling the rotation speed of the engine 6
Is always urged to the low speed side by a governor spring (not shown).

As shown in FIG. 5, the engine accelerator control device B is provided with operation levers 8a to 11a or 8b to 8c for forward and reverse tilt operation for switching control of hydraulic switching valves 8 to 11 for controlling driving of a hydraulic crane. An operation conversion mechanism 17 that loosely engages the operation lever 11b to convert the tilt and return movement of the operation lever in a forward / reverse tilt region of a predetermined amount or more from the neutral position of the operation lever into a reciprocating motion and outputs the reciprocating motion. The output of the conversion mechanism 17 is connected to an accelerator lever 6a of the engine.

The operation conversion mechanism 17 in the engine accelerator control device B includes cam plates 17a... Attached to the base ends 8g to 11g of the operation levers 8b to 11b, respectively.
And a swing arm 17b which is supported near the cam plate 17a... And whose center point is swingably supported by a support shaft 19 attached to the base 1 side of the hydraulic crane. Roller 17c attached to the tip of 17b1
Is constituted by a swing arm 17b loosely engaged with each of the cam plates 17a. The roller 17c of the swing arm 17b engages with each of the cam plates 17a in a forward / reverse tilt region of a predetermined amount or more from a neutral position of each operation lever, and causes the tilt of each operation lever in the tilt region to be a swing arm. It is taken out as swinging of the operating lever 17b in the forward direction (counterclockwise in FIG. 5), and the returning operation of each operating lever to the neutral position in the area is swinging of the swinging arm 17b in the reverse direction (clockwise in FIG. 5). To be taken out. The swing arm 17b includes an arm 17b2 extending in a direction opposite to the arm 17b1.
The tip of 7b2 is the output of the operation conversion mechanism 17. The operation conversion mechanism 17 converts the tilt and return movement of the operation lever in a forward / reverse tilt region of a predetermined amount or more from the neutral position of the operation lever into a reciprocating movement of the arm 17b2 and outputs the converted movement.

The above-mentioned connecting mechanism 18 controls the forward movement of the arm 17b2 caused by the swinging movement of the swing arm 17b in the operation conversion mechanism 17 in the forward direction (counterclockwise in FIG. 5). 6a is transmitted as a movement toward the speed increasing side against the return spring, and the swing arm 17b2 accompanying the swing in the reverse direction (clockwise in FIG. 5).
Is transmitted as a movement of the accelerator lever 6a of the engine 6 to the deceleration side. In the example of FIG. 5, this connecting mechanism is constituted by a push-pull cable.

Incidentally, the operation conversion mechanism 17 is a real
No. -25210, which has been described as including a cam plate 17a and a swing arm 17b as already described.
No. 575. In short, as the operation conversion mechanism 17, direct or indirect operation levers 8a to 11a, 8b to 11b capable of forward and reverse tilting operation for switching control of the hydraulic switching valves 8 to 11 for controlling the driving of the hydraulic crane are provided. An operation conversion mechanism loosely engaged with the operation conversion mechanism, as long as the operation conversion mechanism outputs tilting and returning movements of the operation lever in a forward / reverse tilting area of a predetermined amount or more from the neutral position to the output unit as reciprocating movements. It is.

By the way, the conventional engine accelerator control device B of the hydraulic crane constructed as described above operates the operating levers 8a to 11a and 8b to 11b to switch the corresponding hydraulic switching valves 8 to 11. This is extremely convenient because the control of the amount and the control of the rotation speed of the engine 6 can be performed. However, the above-mentioned conventional engine accelerator control device is provided with each of the operation levers 8a to 11a in the forward / reverse tilting region of a predetermined amount or more from the neutral position.
In the tilting directions of 8b to 11b, a spring (not shown) that biases the hydraulic switching valve corresponding to the operation lever in a direction of returning to neutral, and a return force to the accelerator lever 6a of the engine 6 are biased. The operation must be performed against the governor spring, and the operation of each operation lever in the tilt direction requires a large operation force. In particular, since the governor spring is strong in order to ensure the stability of engine rotation, the tilting operation force of the operating levers 8a to 11a and 8b to 11b in the tilting region is very large. Had become.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel engine accelerator control device in which an increase in the operating force of an operating lever by a governor spring for applying a restoring force to an accelerator lever 6a of the engine is reduced. To solve the problems of the conventional engine accelerator control device.

[0014]

Means for Solving the Problems In order to achieve the above object, an engine accelerator control device for a hydraulic crane according to the present invention is configured as follows. Fitted with its base 1 on the chassis frame between the cab and the truck bed, engine in a hydraulic crane which is driven by a hydraulic pressure generated in the hydraulic pump 7 driven by the engine 6 of the track
Operating levers 8a to 11a and 8b capable of forward and reverse tilting operation for switching control of hydraulic switching valves 8 to 11 of a center position P port open type P port that controls driving of a hydraulic crane in four directions and three positions. 11b are directly or indirectly loosely engaged with the operating levers 8a to 11a, 8a in a forward / reverse tilting region of a predetermined amount or more from the neutral position.
an operation converting mechanism 17 for converting the tilting and returning movements of b to 11b into reciprocating movement and outputting the reciprocating movement;
Connecting means 18 for linking the output of the engine 6 with the accelerator lever 6a of the engine 6, and operating levers 8a to 11a,
In an engine accelerator operating device of a hydraulic crane configured to increase and decrease the rotation of the engine 6 in accordance with the tilting and returning movements of 8b to 11b, the input part of the connecting means 18 is converted into the operation conversion. A servo cylinder connected to a mechanism 17 side and having an output portion connected to the accelerator lever 6a side and driven by hydraulic pressure of a pump oil passage 12 of the hydraulic pump 7 as a power source, wherein the output portion is the input portion An engine accelerator operating device for a hydraulic crane , comprising a servo cylinder driven to follow the displacement of the engine.

[0015]

The engine accelerator control device of the hydraulic crane according to the present invention, constructed as described above, comprises operating levers 8a to 8a.
a, 8b to 11b are operated to switch the hydraulic switching valves 8 to 11, thereby driving the hydraulic crane. In a state where the hydraulic switching valves 8 to 11 are switched, the carry-over oil passage of the hydraulic switching valve involved in the switching is shut off, so the hydraulic pressure of the pump oil passage 12 is high. The tilting and returning movements of the operating levers 8a to 11a and 8b to 11b in the tilting operation region equal to or more than a predetermined position from the neutral position are converted into reciprocating motion by the operation converting mechanism 17, and the reciprocating motion reduces the rotation speed of the engine 6. The increase / decrease operation is similar to that of a conventional hydraulic crane engine accelerator operating device. However, according to the present invention, the operation converting mechanism 17 and the accelerator lever 6a of the engine 6 are connected. The connecting means 18 is provided with a servo cylinder driven by the hydraulic pressure of the pump oil passage 12 as a power source, the output part of which is driven to follow the displacement of the input part. Of the governor spring directly operates the operating levers 8a to 11a and 8b to 11
Since it does not act as a tilting reaction force of b, the operating force of the operating lever is greatly reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an engine accelerator control device for a mobile crane according to the present invention will be described below with reference to FIGS. First, the control device for the engine accelerator of the hydraulic crane of the present invention is obtained by adding a part of the configuration to the conventional engine control device for the hydraulic crane shown in FIGS. In the following description, the same reference numerals are used as synonyms.

(First Embodiment) In FIG. 1, reference numeral 20 denotes a servo cylinder interposed in the connecting means 18. The servo cylinder 20 includes a cylinder 21 fixed to the base 1, a piston rod 22 penetrating one side wall of the cylinder 21 slidably in an oil-tight manner,
A piston 24 which is slidably fitted in a cylinder 21 and is fixed to a base end of the piston rod 22 to define a piston rod side oil chamber 23 in the cylinder 21; A compression spring 25 interposed between the piston rod 22 and the piston 21 for urging the piston rod 22 in the extension direction with respect to the cylinder 21; and control valve means 26 attached to the piston rod 22. The control unit 26 controls the supply and discharge of the pressure oil to and from the side oil chamber 23.

The control valve means 26 includes a spring 26a
, The piston rod side oil chamber 23 and the tank 13 are connected at the offset position I, and the piston rod side oil chamber 23 and the pump are connected at the operation position II. It is configured to connect the oil passage 12. Since the control valve means 26 moves together with the piston rod 22, each pipe connected to the control valve means 26 can follow the movement. The operation section 26 b of the control valve means 26 constitutes an input section of the servo cylinder 20, and the piston rod 22 constitutes an output section of the servo cylinder 20. The input portion (operating portion of the control valve means 26) 26b of the servo cylinder 20 is connected to the operation conversion mechanism 17 side, and the output portion (piston rod) 22 of the servo cylinder 20 is connected to the accelerator lever 6a of the engine 6. Connected to the side.

Next, the operation will be described. In the same manner as in the conventional engine accelerator control device, the tilting and return movement of the operating lever in the forward / reverse tilt region of a predetermined amount or more from the neutral position is extracted as reciprocating motion by the operation conversion mechanism 17 as in the conventional engine accelerator control device. It is. The forward or backward movement taken out by the operation conversion mechanism 17 is transmitted to the input section of the servo cylinder 20 (the operation section 26b of the control valve means 26).
Is switched to the operating position II or the offset position I. When the control valve means 26 is switched to the operation position II, pressure oil is supplied from the pump oil passage 12 to the piston rod-side oil chamber 23 of the servo cylinder 20, and the output portion (piston rod) 22 of the servo cylinder 20 contracts. Then, the accelerator lever 6a of the engine 6 is operated to the high speed side. When the control valve means 26 is switched to the operating position I, the piston rod side oil chamber 23 of the servo cylinder 20
Is connected to the tank 13 so that the output portion (piston rod) 22 of the servo cylinder 20 extends, and the engine 6
Is operated to the low speed side. Since the control valve means 26 is attached to the output portion (piston rod) 22 of the servo cylinder 20, the expansion and contraction of the output portion 22 is caused by the reciprocating amount input to the input portion 26b of the servo cylinder 20, that is, the operation conversion mechanism. It follows the amount of reciprocation output from 17. In this manner, the accelerator lever 6a of the engine 6 is driven by using the hydraulic pressure of the pump oil passage 12 as a power source. Since it does not act, the operating force of the operating lever is greatly reduced.

(Second Embodiment) In the first embodiment, both supply and discharge of pressure oil to the piston rod side oil chamber 23 of the servo cylinder 20 are directly controlled by the control valve means 26. Therefore, the control valve means 26 is configured as a three-port type. However, the control valve means 26 may be of a two-port type as shown in FIG. That is, in FIG. 2, at the offset position I due to the spring 26a, the control valve means 26 is connected to the pump oil passage 12 and the piston rod side oil chamber 23.
In the operation position II, the pump oil passage 12 and the piston-rod-side oil chamber 23 are connected to each other to constitute a two-port valve. In this case, the piston rod side oil chamber 23 is always connected to the tank 13 via the throttle 27. In this example, when the control valve means 26 is operated to the operation position II, the amount of oil supplied from the pump oil passage 12 to the piston rod side oil chamber 23 via the operation valve means 26 passes through the throttle 27. So that it is larger than the amount of oil flowing into the tank 13
The aperture is set. When the control valve device 26 reaches the offset position I, the pump oil passage 1
While the supply of the pressure oil from 2 is cut off, the hydraulic oil flows out from the piston rod side oil chamber 23 through the throttle 27, so that the output portion (piston rod) 22 of the servo cylinder 20 is reduced. In this embodiment, it can be easily understood that the servo cylinder 20 operates in the same manner as in the first embodiment.

In each of the above embodiments, an example is shown in which the control valve means 26 is attached to the outside of the cylinder 21 of the servo cylinder 20.
For example, the operation unit 2 is disposed in the piston rod 22.
Of course, 6a may be configured to be performed via an operation rod penetrating the other end wall of the cylinder 21 (the side opposite to the end wall through which the piston rod 22 penetrates).

[0022]

The engine accelerator control device of the hydraulic crane of the present invention configured as described above has only the addition of a servo cylinder driven by the hydraulic pressure of the pump oil passage 12 as a power source to the conventional one, and has an operating lever. Since the operating force of the device can be reduced, the practical effect is large.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an engine accelerator control device of a hydraulic crane according to the present invention.

FIG. 2 is an explanatory diagram of another embodiment of the engine accelerator control device of the hydraulic crane according to the present invention.

FIG. 3 is an explanatory diagram of an operation unit of the hydraulic crane.

FIG. 4 is an explanatory diagram of a hydraulic control circuit of the hydraulic crane.

FIG. 5 is an explanatory diagram of a conventional engine accelerator control device for a hydraulic crane.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 base 2 swing motor 3 undulating cylinder 4 telescopic cylinder 5 winch motor 6 engine 6a accelerator lever 7 hydraulic pump 8 hydraulic switching valve 9 hydraulic switching valve 10 hydraulic switching valve 11 hydraulic switching valve 8a operating lever 9a operating lever 10a operating lever 11a operating Lever 8b Operation lever 9b Operation lever 10b Operation lever 11b Operation lever 8c Connection rod 9c Connection rod 10c Connection rod 11c Connection rod 17 Operation conversion mechanism 17a Cam plate 17b Swing arm 18 Connection means 19 Support shaft 20 Servo cylinder

Claims (1)

(57) [Scope of request for utility model registration] 1. An engine accelerator control device for a hydraulic crane, which is mounted on a chassis frame between a truck cab and a cargo bed and is driven by a hydraulic pressure generated by a hydraulic pump driven by an engine of the truck , comprises: Center position in four directions and three positions for controlling driving P port Directly or indirectly loosely engaged with an operation lever capable of forward / reverse tilt operation for switching control of an open hydraulic switching valve, from a neutral position An operation conversion mechanism that converts the tilt and return movement of the operation lever into a reciprocating motion and outputs the reciprocation in a forward or reverse tilting region equal to or more than a fixed amount, and a connection unit that interlocks and outputs the output of the operation conversion mechanism to an accelerator lever of the engine The engine is operated in accordance with the tilting and returning movement of the operating lever in a forward / reverse tilting range of a predetermined amount or more from the neutral position. In an engine accelerator operating device for a hydraulic crane configured to increase and decrease the rotation, the input unit is connected to the operation conversion mechanism side and the output unit is connected to the accelerator lever side in the connecting means. A servo cylinder connected and driven by a hydraulic pressure of a pump oil passage of the hydraulic pump as a power source, wherein the output unit is provided with a servo cylinder driven to follow the displacement of the input unit. Accelerator operating device for hydraulic crane