KR101800718B1

KR101800718B1 - Speed control device of hydraulic actuator

Info

Publication number: KR101800718B1
Application number: KR1020167015890A
Authority: KR
Inventors: 마사시 아츠미
Original assignee: 가부시기가이샤다다노
Priority date: 2014-01-15
Filing date: 2015-01-05
Publication date: 2017-11-23
Also published as: KR20160090834A; JP2015132226A; CN105814296B; JP6202744B2; WO2015107868A1; CN105814296A

Abstract

Provided is a speed control device for a hydraulic actuator that is capable of high and low switching operation of the engine speed and which is simple and does not generate malfunctions. A control valve V for controlling the operation speed of the winch motor M and an accelerator for increasing and decreasing the number of revolutions of the engine E and a manual control valve for controlling the pressure- An operation lever Lw, a cam portion 2 for transferring the movement of the operation lever Lw to the accelerator, and a cam device 1 composed of an accelerator roller 5. The cam portion 2 is composed of a high-speed cam 10 for moving the accelerator roller 5 small and a normal cam 20 for moving the accelerator roller 5 largely. Since the high-speed cam 10 and the ordinary cam 20 move the accelerator rollers 5 in different amounts, the engine speed can be increased or decreased in a high range or increased or decreased in a low range by selecting either one.

Description

[0001] SPEED CONTROL DEVICE OF HYDRAULIC ACTUATOR [0002]

The present invention relates to a speed control device for a hydraulic actuator. More particularly, to a device for controlling the speed of an actuator for a working machine of the type in which the hydraulic actuator is driven by a hydraulic pump and the hydraulic pump is driven by an engine. The present invention can be applied to an actuator in any industrial field as long as it is a working machine using a hydraulic actuator as described above.

In the working machine using the hydraulic pump driven by the engine as described above, the speed control of the hydraulic actuator is performed by controlling two factors of the valve opening amount (opening amount) of the hydraulic actuator control valve and the engine speed for rotating the hydraulic pump .

Manually controlling the valve opening amount and the engine speed of the control valve manually is a troublesome task for the operator, so a technology capable of operating the valve opening degree and the engine speed simultaneously with one operation lever has already been developed .

However, in this prior art, when the valve opening is increased, the number of revolutions of the engine increases to increase the number of revolutions of the engine. As a result, the fuel consumption increases and the noise increases, and the operation speed of the hydraulic actuator is increased more than necessary, .

Therefore, in order to solve this problem, the prior art of Patent Document 1 has been proposed.

In this prior art, the valve operating lever is displaced back and forth in the axial direction with respect to the accelerator operation link of the engine to change the engagement position of the engaging portion and the engaging portion. According to this conventional technique, even if the changeover valve is changed in response to the movement of the operating lever, the accelerator operation link can be operated late so that the upper limit of the engine speed can be limited even if the valve operating lever is moved to the end position have. In other words, it is possible to switch between high and low of the engine speed.

However, the above-mentioned conventional technique uses a mechanism for changing the fitting length of the shaft and the cylinder, and a mechanism for changing the coupling position around the shaft of the coupling part and the coupling part, It is a complicated structure. For this reason, there has been a problem in that troubles are likely to occur, and the degree of looseness between the engaging portion and the engaging portion must be adjusted by a human hand.

However, in a winch, which is a type of a working machine, a high-low speed winch using a high-speed hydraulic motor has already been used. There are several types of high and low speed hydraulic motors, such as swash plate type motors and eccentric type motors, and they are already in practical use, but they are very expensive because the production quantity is still small.

Also, if the speed control is automatically performed by using such a high / low speed hydraulic motor, the controller and many sensors are necessary, and the equipment cost becomes high.

As a result, automatic speed control systems have not yet been introduced for compact machines such as truck mounted cranes.

Utility Model Registration No. 2528724

SUMMARY OF THE INVENTION It is an object of the present invention to provide a speed control device for a hydraulic actuator which is capable of performing a high-low-speed switching operation of a hydraulic actuator in consideration of the above circumstances, Another object of the present invention is to provide a speed control device for a hydraulic actuator that can control a speed at a low cost by using a simple manual device.

A speed control device for a hydraulic actuator according to a first aspect of the present invention is a working machine for operating a hydraulic actuator for a working machine with a hydraulic pump and driving the hydraulic pump with an engine, the control device comprising: a control valve for controlling an operating speed of the hydraulic actuator; A manual control lever for directly controlling a pressure changeover direction and a valve opening degree in the control valve; a cam for transmitting the movement of the operation lever to the rotation number controller and a cam follower wherein the cam device comprises a high-speed cam for moving the cam follower to a small extent and a normal cam for moving the cam follower to a large extent, and the high-speed cam and the normal cam are mutually engaged with each other And the cam face of the high-speed cam or the normal cam is moved to the cam arm And a position fixing mechanism fixed to an operating position for moving the finger.

According to a second aspect of the present invention, there is provided a speed control device for a hydraulic actuator according to the first aspect of the present invention, wherein the cam device is such that the high speed cam is fixed to the base end portion of the operation lever, And the position fixing mechanism is a two-position holding notch that can be held at a position where the normal cam is advanced and retracted.

The hydraulic actuator according to the third aspect of the present invention is the hydraulic actuator according to the first or second aspect of the invention wherein the hydraulic actuator is a high and low speed variable motor and the high speed low speed variable mode And a switch operator for actuating a change-over switch for switching the operation of the switch.

In the hydraulic actuator of the fourth aspect of the present invention, in the third aspect of the present invention, the switch actuator is a pressing piece formed on the normal cam, and when the normal cam is in the operating position, .

In the hydraulic actuator of the fifth aspect of the present invention, in the third aspect of the present invention, the switch actuator is a switch actuating plate, and is slidably mounted on the cam follower in the cam portion and is urged toward the cam follower (Biased).

According to the first aspect of the present invention, when either one of the high-speed cam and the normal cam is pushed and pulled, the cam surface of the cam can be fixed to the action position. Since the high-speed cam and the normal cam differ in the amount of moving the cam follower, the engine speed can be increased or decreased in a high range or increased or decreased in a low range by selecting either one of the cams. In addition, since the structure of the cam device is a structure in which two cams are overlapped, and the number of components is small and a simple structure is adopted, it is possible to realize a low price and a failure. In addition, by replacing the cam device, it can be mounted later on an existing working machine.

According to the second invention, when the normal cam is advanced, the cam follower is moved to the normal cam, and when the normal cam is retracted, the cam follower can be moved to the high speed cam. Since the advancing position and the retracting position of the normal cam can be held by the two position holding notches, it is possible to reliably control the speed of the hydraulic actuator without causing the normal cam to malfunction during the lever operation.

According to the third invention, when the high-speed cam or the normal cam is selected, the mode change is simple since the high-speed variable motor is automatically switched to the high-speed mode or the low-speed mode by the switch operator.

According to the fourth invention, when the normal cam is in the operating position, it is possible to switch the high / low speed mode of the high / low speed variable motor by operating the changeover switch with the pushing piece.

According to the fifth invention, it is possible to switch the high-low speed mode of the high-low speed variable motor by operating the switch on the switch operation plate.

Fig. 1 is a perspective view of the cam device in the speed control device of the present invention,
2 is a hydraulic circuit diagram of a winch motor which is an example of a hydraulic actuator to which the present invention is applied,
Fig. 3 shows a cam device according to the first embodiment, wherein (A) is a perspective view showing the front side, (B) is a perspective view showing the back side,
Fig. 4A is an explanatory diagram of the cam for high speed, Fig. 4B is an explanatory diagram of the cam for normal use,
5 is an explanatory view for explaining use of the cam for high speed,
6 (A) is a perspective view showing the front side, (B) is a perspective view showing the back side, and Fig. 6
Fig. 7 (A) is an explanatory diagram of the cam for normal use, Fig. 7 (B)
8 (A) is an explanatory view of the high-speed cam, (B)
9 is a diagram explaining the relationship between the lever operation amount and the hook speed in the speed control apparatus of the first embodiment,
10 is a diagram explaining the relationship between the lever operation amount and the hook speed in the speed control apparatus of the second embodiment,
11 is a side view of a small crane, which is an example of a work vehicle,
12 is a front view of the miniature crane of Fig.

Next, an embodiment of the present invention will be described with reference to the drawings.

First, a basic structure of a truck mounted crane will be described as an example of a work vehicle to which the present invention is applied.

In Figs. 11 and 12, CP denotes a crane post, B denotes a multi-stage boom, F denotes a hook, and J denotes an outrigger jack. The crane post CP is pivoted on the swivel pedestal, the boom B is relieved by the undulating cylinder Cy, and is stretched and contracted by an unillustrated boom built-in stretching cylinder.

The hook F is raised or lowered by hoisting or lowering the wire rope with the winch W installed on the crane post CP.

The above-mentioned multi-stage boom B, hook F, outrigger jack J, winch W and the like are examples of working machines in the claims. In addition, a stretching cylinder, a relief cylinder, a winch motor, a jack cylinder, and the like are examples of hydraulic actuators in the claims.

Each of these hydraulic actuators is connected with a known hydraulic circuit including a hydraulic pump, a hydraulic control valve, and a tank. The hydraulic pressure control valve is adapted to be able to switch the pressure oil in the transfer direction and adjust the valve opening degree with a plurality of manual operation levers Lv shown in Fig.

In the following embodiments, a speed control device to which the present invention is applied to a winch motor will be described.

Fig. 1 shows the vicinity of the operating lever Lw of the winch motor M. Fig. This operation lever Lw is one of a plurality of manual operation levers Lv shown in Fig.

A cam portion 2 is provided at a base portion of the operation lever Lw. The cam portion 2 is supported by a vertical shaft 4 and is provided around the vertical shaft 4 so that the operation lever Lw can be inclined leftward and rightward.

A cam follower 5 in the form of a cylinder is arranged so as to face the cam portion 2 and the cam follower 5 is supported by a link 6 and a support shaft 7, As shown in Fig. The cam unit 2 and the cam follower 5 constitute a cam device 1 as claimed in the claims.

In the following embodiments, the cam followers 5, which are referred to in the claims, are controlled by the accelerator of the engine. As the accelerator roller 5 for performing the above-described operation.

The arm 8 is connected to the lower portion of the support shaft 7 so as to extend radially outwardly and the accelerator wire 9 connected to the arm 8 is connected to an accelerator for controlling the engine speed of the work vehicle. Therefore, when the accelerator roller 5 is pivoted and the excel wire 9 is pushed and pulled, the number of revolutions of the engine increases or decreases, and the amount of discharge of the hydraulic pump also increases or decreases, so that the driving speed of the hydraulic actuator increases or decreases.

On the other hand, the left and right tilting of the operation lever Lw is connected to the spool end of the hydraulic control valve V (shown in Fig. 2) for controlling the winch motor by a dedicated link or the like, Direction and the amount of opening of the valve can be controlled.

Next, the hydraulic circuit of the winch motor M to be subjected to the speed control will be described with reference to Fig.

M is a hydraulic motor for a winch (hereinafter referred to as a winch motor), and a hydraulic pressure control valve V, a hydraulic pump P and a tank T Circuit is used.

The winch motor (M) is a high / low speed hydraulic motor and is a known hydraulic actuator capable of selecting two modes of low speed rotation mode and high speed rotation mode. In low speed rotation mode, low speed high torque can be outputted compared with high speed rotation mode. In high speed rotation mode, even if same flow rate is supplied, high speed but low torque is obtained.

The switching of the high and low speed modes can be performed by changing the flatness of the rotor if the winch motor M is a radial type and by changing the inclination angle of the drive shaft and the cylinder block if it is an axial type . The winch motor M is switched to the high / low speed mode by the switching cylinder Cm and the solenoid operated on / off valve Vm is provided for controlling the expansion / contraction of the switching cylinder Cm. Further, this solenoid S is connected to the power source via the changeover switch 40. [ The switch 40 is mounted on the cam portion 2 to be described later.

The hydraulic pump P is rotationally driven by the engine E of the working vehicle, and the engine speed is increased or decreased by the accelerator A. Further, the control of the engine speed is performed through the accelerator wire 9 which is pushed and pulled by the operation lever Lw shown in Fig. 1 as described above.

(First Embodiment)

Next, the cam portion 2 in the first embodiment will be described with reference to Figs. 3 to 5. Fig.

As shown in Fig. 3, the cam portion 2 includes a high-speed cam 10 and a normal cam 20. The high-speed cam 10 is a plate material bent in a U shape in a side view, and its base is mounted on the base of the operation lever Lw. The cam plate of the high-speed cam 10 is formed with a hole 11 and a guide groove 12 through which the above-described shaft 4 passes.

The high speed cam 10 is fixed to the shaft 4 passing through the hole 11 so that the shaft 4 can be turned freely or the shaft 4 is fixed and the high speed cam Or the entire cam portion 2) may be inclined leftward and rightward.

The guide groove 12 is curved and guides the inclination of the cam portion 2 in the left and right directions by guiding the guide shaft 3 shown in Fig. 1 and regulating the stroke end thereof.

As shown in Fig. 4A, the profile of the cam surface 13 of the high-speed cam 10 is formed by the non-control surface 14 at the center portion and the rotation speed control surfaces 15 and 15 at both sides thereof . The control surface 14 is a portion which does not control the engine speed and while the control surface 14 is in contact with the accelerator roller 5, The switching direction of the hydraulic control valve V and the valve opening degree are controlled by the system.

The rotational speed control surfaces 15 and 15 on both sides of the cam surface 13 control the rotational speed of the engine E shown in FIG. The arm 8 swings and the accelerator wire 9 is pushed and pulled to increase or decrease the number of revolutions of the engine.

As shown in Fig. 4 (B), the normal cam 20 is slidably provided on the back surface of the high-speed cam 10. As shown in Fig. The normal cam 20 has a shape similar to that of the high speed cam 10 and has a curved guide groove 22, a switch actuator 26 and a ring 27.

The guide groove 22 is formed to have a wider groove width than the guide groove 12 of the high speed cam 10 and is pulled to the non-acting position even when the normal cam 20 is pushed to the action position The guide shaft 3 shown in Fig.

The switch operator 26 is an operator for turning on and off the change-over switch 40. When the normal operator 20 is pushed to the operating position, the switch operator 26 switches the switch 40 So as to be operated.

The collar 27 is provided for holding the human's finger and for pushing and pulling the normal cam 20 with the human hand.

The profile of the cam surface 23 of the normal cam 20 is constituted by the central non-control surface 24 and the rotation speed control surfaces 25 and 25 on both sides thereof. The control surface 24 is a portion which does not control the engine speed and while the control surface 24 is depressing the accelerator roller 5, The switching direction of the hydraulic control valve V and the valve opening degree are controlled.

The rotation speed control surface 25 of the normal cam 20 is a portion for controlling the rotation speed of the engine E shown in Fig. 2 and is larger than the rotation speed control surface 15 of the above- The cam surface is higher. That is, it is possible to increase the number of revolutions of the engine by pushing the accelerator wire 9 greatly.

Three guide pins 17 are provided on the back surface of the high speed cam 10 and two guide long holes 28 and one notch long hole 29 are provided on the cam plate of the normal cam 20 have. The two guide pins (17) are fitted in two guide long holes (28), and serve as slide guides. A two-position holding notch 29n is formed in the notch long hole 29 and one guide pin 17 is fitted in the two position holding notch 29n. The two-position retaining notch 29n has a function of allowing the guide pin 17 to move between two holes of the guide pin 17 with slight elastic deformation and to hold the guide pin 17 in the hole.

Therefore, it is possible to manually change the normal cam 20 between the cam working position and the non-working position, and furthermore, it is possible to keep the cam from moving arbitrarily at any position. Therefore, a malfunction can be prevented. This apparatus is a position fixing apparatus as claimed in the claims.

Next, a description will be given of a speed changing method by the cam device 1 including the cam portion 2 and the accelerator roller 5. [

(Normal operation)

As shown in Fig. 4 (B), the normal cam 20 is pushed out to be the acting position. In this case, normal operation can be performed from the low speed region to the high speed region as follows.

(1) Selection of cam

When the normal cam 20 is pushed out, the cam surface 23 protrudes from the cam surface 13 of the high-speed cam 10 and becomes the operating position for pressing the accelerator roller 5.

At this time, the control surfaces 14 and 24 are the same height for both the normal cam 20 and the high speed cam 10, but the rotation speed control surface 25 of the normal cam 20 is the same as the high speed cam 10 The rotational speed control surface 15 of the engine 1 is higher than the rotational speed control surface 15 of the engine.

(2) High and low switch

The switching cylinder Cm shown in Fig. 2 is actuated and the winch motor M is driven at a low speed by turning on the switch 40 when the switch operator 26 is pressed by pushing the switch 40 at the same time as the ordinary cam 10 is pushed out (High) torque is output.

(3) Operation

In the above situation, when the operation lever Lw is moved to move the normal cam 20 left and right, normal operation becomes possible.

The contents of the normal operation will be described with reference to Fig. 9 (A).

9 (A), the vertical axis represents the flow rate and the horizontal axis represents the lever pulling amount S of the operation lever Lw.

The middle graph shows the valve opening of the hydraulic control valve V and the bottom graph shows the engine revolutions. The area below the point A on the horizontal axis is the valve opening control area, and the point A or above is the engine rotation speed control area.

The engine speed (thin line e1) shown in the lower graph maintains a normal rotation (idle state) of 800 rpm at the point A or lower, and the number of revolutions increases linearly after the point A to 2000 rpm. The valve opening degree (thin line v) of the hydraulic pressure control valve V shown in the interruption graph linearly increases from point A to point B slightly larger than point A and the same degree of opening after point B , E.g., 20L).

Next, the contents of the normal operation will be described based on the upper graph.

When the operation lever Lw is moved in the area smaller than the point A, that is, while the non-control surface 14 is in contact with the accelerator roller 5, the hydraulic control valve V is rotated ) Switch in both directions to increase or decrease the valve opening. In this case, the flow rate is controlled only by the degree of opening of the valve, and the flow rate introduced into the winch motor M varies from 0 to 20 L / min, for example. Therefore, the winch speed is low and the fine operation of moving the hook F at a low speed is possible.

When the operation lever Lw moves greatly in the region beyond the point A and the accelerator roller 5 is pressed on the rotation speed control surface 15, the accelerator roller 5 moves greatly as the lever pulling amount is increased, 9) is increased. Therefore, the engine speed can be linearly increased from the idle state (800 rpm) to, for example, 2000 rpm, and the hydraulic oil discharge amount of the hydraulic pump P can be increased, for example, from 20 L / min to 60 L / min.

In this case, for example, a maximum of 60 L / min of working oil is supplied to the winch motor M, and the hook F can be moved at 19 m / min, for example, as indicated by a thick solid line fs. In this normal operation, a high torque can be output, and a heavy object (medium amount) can be towed.

Further, since the engine speed is increased, noise and the like are increased.

(High-speed operation)

As shown in Fig. 5 (B), the normal cam 20 is pulled in and the high-speed cam 10 is set as the acting position. In this case, high-speed operation is performed at a low flow rate.

(1) Selection of cam

The cam surface 23 of the normal cam 20 is lower than the cam surface 13 of the high speed cam 10 when the normal cam 20 is returned and the high speed cam 10 is brought to the operative position It may have the same height portion).

(2) High and low switch

The normal operation cam 20 is pulled in, so that the switch operator 26 is released from the changeover switch 40 and turned OFF. Therefore, the winch motor M is switched to the high speed mode in which the low torque is outputted at high speed.

(3) Operation

In this situation, when the operating lever Lw is moved to move the high-speed cam 10 to the left and right, high-speed operation becomes possible.

The contents of the high-speed operation will be described with reference to Fig. 9 (B).

Since the cam surface 13 of the high-speed cam 10 is low, the amount of movement of the accelerator roller 5 is small even when the operation lever Lw is turned largely to the left and right. Therefore, as indicated by a thin line e2 in the lower graph of Fig. 9 (B), the engine speed rises only to, for example, 1400 rpm. And is about 3/4 as compared with the dotted line e1 representing the engine revolution speed (up to 2000 rpm) during normal operation.

The engine speed is in the idling state (800 rpm) while the operation lever Lw is moved to the point A or below, that is, while the uncontrolled surface 24 is in contact with the accelerator roller 5, The incoming flow rate increases or decreases linearly up to, for example, 20 L / min. However, since the winch motor M in the high speed mode is rotated at a high flow rate even at a small flow rate, the hook speed fs is fast. For this reason, light loads can be raised and lowered quickly, but fine-tuning operations become difficult instead.

When the operating lever Lw is moved to the point A or higher, the flow rate increases because the number of revolutions of the engine increases. However, since the number of revolutions is suppressed to 1400 rpm at the maximum, the flow rate is also limited to a maximum of, for example, 40 L / min.

In the high speed mode, as described above, even if the winch motor M has a small flow rate, the number of revolutions increases, so that a high hook speed fs (for example, up to 19 m / min as in normal operation) can be maintained even after the point A.

In this case, noise is suppressed because the engine speed is kept low. This mode is suitable for daytime and nighttime work.

When the winch motor M is in the high speed mode, since the output of the winch W does not become high torque, it can be used for winding up a light weight shipment.

As described above, the hook speed is the same as before, but the engine speed can be reduced to suppress the fuel consumption. It is also effective to suppress the oil temperature rise in the hydraulic system.

(Second Embodiment)

The cam device 1 of the second embodiment will be described with reference to Figs. 6 to 8. Fig.

The high-speed cam 10 and the normal cam 20 constituting the cam portion 2 shown in Fig. 6 (A) are the same as those in the first embodiment. This embodiment is characterized in that a switch operating plate 30 dedicated to switch switching operation is provided instead of forming a switch operator in the normal cam 20. [ The switch operating plate 30 is provided with a pushing piece 31 for turning the switch 40 on and off.

6 (B), the switch actuating plate 30 is disposed on the back surface of the normal cam 20 and is slidably fitted to the guide pin 17 through a long hole (not shown) . In addition, although it is pushed toward the accelerator roller 5 at all times by an appropriate force applying means (not shown) such as a spring, when it comes into contact with the accelerator roller 5, it is pushed back by the accelerator roller 5.

Next, the speed switching method according to the cam apparatus 1 of the second embodiment will be described.

(Normal operation)

The normal operation is carried out by pushing the normal cam 20 to the operating position as shown in Fig. In this case, normal operation can be performed from the low speed region to the high speed region.

7 (A) shows a state in which the non-control surface 24 of the normal cam 20 is used. In this case, the valve opening degree by the operation lever Lw at the point A or lower in Fig. The operation is performed according to the adjustment. Fig. 7B shows a state in which the rotation speed control surface 25 is used. In this case, the operation is performed in which the increase or decrease in the engine speed at the point A or more in Fig. 9A is added or decreased.

The details of such operation are the same as those of the first embodiment described above.

(High-speed operation)

As shown in Fig. 8 (B), the normal cam 20 is pulled in and the high-speed cam 10 is set as the operative position. In this case, high-speed operation is performed.

(1) Selection of cam

(2) High and low switch

When the normal cam 20 is manually pulled in, the switch operating plate 30 is in a position protruding toward the accelerator roller. Therefore, when the normal operating cam 20 is returned to the accelerator roller 5, The piece 31 is turned on by pressing the changeover switch 40. [ For this reason, the winch motor M is switched to the high speed mode in which the high speed low torque is output.

(3) Operation

As shown in Fig. 8 (A), in the state in which the accelerator roller 5 is pressed on the non-control surface 14 of the high-speed cam 10, the operation at the point A or less in Fig. 10 is performed. In this case, since the winch motor M is still in the low speed mode, the speed of the hook F (thick solid line fs1) is not fast. For this reason, it is liable to perform fine motion.

8 (B), when the high-speed cam 10 is moved to the left and right beyond the non-control surface 14 by moving the operation lever Lw, the switch operating plate 30 is moved by the accelerator roller 5, The switch 40 is operated to enable the winch motor M to operate at a high speed.

The contents of the high-speed operation will be described with reference to Fig.

Since the cam surface 13 of the high-speed cam 10 is low, the amount of movement of the accelerator rollers 5 is small even when the cam portion 2 is largely turned to the left and right. For this reason, as shown by a thin line (e2) in the lower graph of Fig. 10, the engine speed is only 1400 rpm, for example. Is approximately 3/4 as compared with a fine line e1 (indicated by a dotted line) indicating the number of engine revolutions (maximum 2000 rpm) during normal operation.

The operation is the same as the normal operation while the operation lever Lw is moved to a point smaller than the point A and the non-control surface 14 is depressed on the accelerator roller 5. [ In other words, the engine speed is in the idling state (800 rpm), and the flow rate flowing into the winch motor M linearly increases or decreases to, for example, 20 L / min.

8 (B), the accelerator roller 5 moves the switch operating plate 30, and the pushing piece 31 is moved by the movement of the switch 40 Is switched to ON, the winch motor M is in the high speed mode.

10, the flow rate increases as the number of revolutions of the engine increases. However, since the number of revolutions is limited to 1400 rpm at maximum, the flow rate is also limited to a maximum of, for example, 40 L / min.

The speed of the hook F (thick solid line fs2) is higher than the point A (for example, at a maximum speed of 19 m / min as in normal operation) ).

As described above, even if the hook speed fs2 is increased, the engine speed is limited to be lower than the speed, so that the noise is suppressed. This mode is suitable for daytime and nighttime work.

Further, when the hydraulic motor M is in the high speed mode, the output of the winch W is not high-torque, so that it can be used for winding up a lightweight shipment.

As described above, the hook speed is similar to that of normal operation, but the engine speed can be reduced to suppress fuel consumption. It is also effective to suppress the oil temperature rise of the hydraulic system.

(Example)

Next, examples will be described.

The specifications of the winch motor M in this embodiment are as follows.

The criterion for switching the high and low speed motors M is a normal mode operation at a suspension load of 1.7 t or more and a high speed mode operation at 1.7 t or less.

Cam: Normal cam (20)

High-speed motor capacity: 23.6cc / rev

Maximum engine speed: 2000 rpm

Hook speed maximum: 19m / min

<High-speed mode operation with suspended load 1.7t or less>

Cam: High-speed cam (10)

High-speed motor capacity: 14.7cc / rev

Maximum engine speed: 1400 rpm

Hook speed maximum: 19m / min

As described above, at a hanging load of 1.7 t or less, the hook speed is similar to that of normal operation, but the engine speed can be reduced to reduce fuel consumption. It is also effective to suppress the oil temperature rise in the hydraulic system.

(Other Embodiments)

The high speed cam 10 is fixed to the operation lever Lw and instead of doing so, the normal cam 20 is fixed to the lever 1 and the high speed cam 10 is fixed to the normal cam 20 so as to be slidable.

In this case, the high-speed cam 10 may be provided with a switch operator 26 for operating the switch 40. [

[Industrial Availability]

According to the present invention, it is possible to equip a high and low speed winch simply and inexpensively even in a truck mounted crane which does not have a control device. Further, the present invention can be post-mounted only by replacing the cam device 1 in the lever operating portion of the winch, so that it is less troublesome to add specifications to the existing working machine.

Since the cam device 1 used in the present invention has a simple structure based on the two cams 10 and 20, the number of parts is small and a failure is hard to occur.

In the above embodiment, the invention is applied to a winch of a truck-mounted crane, but the present invention can be applied to various other industrial machines or hydraulic working machines coupled to industrial machines thereof.

The present invention can be applied to a truck mounted with a crane, an automobile transportation vehicle, a high-altitude work vehicle, and the like.

One; Cam device
2; Cam portion
4; Vertical axis
5; Accelerator roller
9; Acceler wire
10; High speed cam
13; Cam face
14; Uncontrolled surface
15; Rotation number control surface
20; Normal cam
23; Cam face
24; Uncontrolled surface
25; Rotation number control surface
26; Switch operator
30; Switch operating plate
40; Switch
M; Winch motor
P; Hydraulic pump
E; engine
V; Hydraulic control valve

Claims

A working machine for operating a hydraulic actuator for a working machine by a hydraulic pump and driving the hydraulic pump by an engine,
A control valve for controlling the operating speed of the hydraulic actuator,
A rotation speed controller for increasing / decreasing the rotation speed of the engine,
A manual operation lever for directly controlling the pressure-switching direction and the valve opening degree of the control valve,
And a cam device composed of a cam portion and a cam follower for transmitting the movement of the operation lever to the rotation speed controller,
The cam device includes a high-speed cam for moving the cam follower in a small direction, a normal cam for largely moving the cam follower,
Wherein the high speed cam and the normal cam are overlapped with each other and the cam surface of the high speed cam or the normal cam is fixed at an operating position for moving the cam follower at a position where one of the high speed cam and the ordinary cam is pushed Characterized in that the speed control device of the hydraulic actuator.

The method according to claim 1,
The cam device is characterized in that the high-speed cam is fixed to a base end portion of the operation lever,
The normal cam is slidably provided with respect to the high-speed cam,
Wherein the position fixing mechanism is a two-position holding notch capable of maintaining a position at a forward position and a backward position of the normal cam.

3. The method according to claim 1 or 2,
The hydraulic actuator is a high-low-speed variable motor,
And a switch actuator for operating a switching switch for switching the high-low speed mode of the high-low speed variable motor to the high-speed cam or the normal cam.

The method of claim 3,
Wherein the switch operator is a pushing piece formed on the normal cam,
Wherein the switch is operated when the normal cam is in the operating position.

The method of claim 3,
Wherein the switch actuator is a switch actuating plate and is provided so as to be slidable toward the cam follower in the cam portion and is given a force toward the cam follower.