JPH0530096U - Control device for swivel in work vehicle - Google Patents

Abstract

(57) [Abstract] [Purpose] For a work vehicle in which a swivel base 2 on a vehicle body 1 is rotationally driven by a drive source 5, while reducing the cost of a turning control mechanism, the power source is turned off by interruption of work or the like. Even when the power is cut off, the control circuit can be maintained in the state before the power is cut off, and excessive swing of the swivel base 2 and malfunction of the moment limiter are eliminated. [Structure] Switches L2, L1 and L3 are provided between the swivel base 2 and the vehicle body 1 for detecting a neutral position, a forward rotation direction limit position and a reverse rotation direction limit position, respectively. Drive source 5
The control device 13 that controls the operation of each of the switches L1 to L3
When the swivel base 2 reaches the swivel limit position in the forward rotation direction or the reverse rotation direction based on the state change of No. 1, the output of the drive source 5 is stopped, and the operation is performed based on the limit detection operation of the forward rotation limit switch L1. The keep relay R1 and the keep relay R2 that operates based on the limit detection operation of the reverse rotation limit switch L3 are included.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement of a restricting device for restricting a swing exceeding a limit of a swivel base in a work vehicle having a swivel swiveling over 360 °.

[0002]

[Prior Art]

 In this type of work vehicle, a potentiometer or rotary encoder is generally used to detect the turning angle of a turntable that turns 360 ° or more, as disclosed in, for example, Japanese Patent Laid-Open No. 59-118690. .. However, potentiometers, rotary encoders, and other angle detectors are expensive, and the swing control mechanism is expensive.

Therefore, the applicant of the present invention makes it possible to detect both the turning direction of the swivel base and the fact that the swivel base has reached the limit swing positions in both forward and reverse directions by using proximity switches, respectively. Has previously proposed to realize the cost reduction (see the specification of Japanese Patent Application No. 2-102414 and the drawings).

There, the control circuit specifies the turning limit in the forward rotation direction and the reverse rotation direction by the detection signals of the proximity switch that detects the turning direction and the proximity switch that detects the limit turning angle, and drives the turning base. Turning is regulated by stopping the supply of working oil to the hydraulic motor.

[0005]

[Problems to be solved by the device]

 According to the above mechanism, the limit turning angle can be detected by an inexpensive proximity switch, etc., so that cost reduction can be realized, but on the other hand, the work is interrupted during turning and the power supply to the control circuit is stopped. It can cause problems. In other words, the control members such as relays are reset to the initial state at the same time as the power failure. If work is restarted in this state, the swivel base will be driven beyond the swivel limit, and for example, the hydraulic hose may be disconnected, or the moment limiter that calculates the overturning moment may go into a serious situation. There is

An object of the present invention is to reduce the cost of the turning control mechanism, and to keep the control circuit in the state before the power is cut off even when the power is cut off due to work interruption or the like. It is to eliminate excessive turning of the platform and malfunction of the moment limiter to improve safety during work.

[0007]

[Means for Solving the Problems]

 The present invention is premised on a work vehicle provided with a swivel mounted on a vehicle body so as to be swivel, a drive source for rotationally driving the swivel, and a control device for controlling an operating state of the drive source.

A neutral detection switch that detects that the swivel is in a neutral position between the swivel and the vehicle body, and a forward rotation limit that detects that the swivel has reached a turning limit position in the forward rotation direction. A switch and a reverse rotation limit switch for detecting that the swivel base has reached the swing limit position in the reverse rotation direction are provided.

The control device is configured to stop the output of the drive source when the swivel base reaches the turning limit position in the forward rotation direction or the reverse rotation direction based on the change in the state of each switch. This control device is characterized by including a keep relay that operates based on the limit detection operation of the forward rotation limit switch and a keep relay that operates based on the limit detection operation of the reverse rotation limit switch.

[0010]

[Action]

 With the above structure, in the present invention, the control device determines the turning state of the turntable based on the operating states of the two keep relays based on the combination signal of the neutral detection switch, the forward rotation limit switch, and the reverse rotation limit switch. Specifically, the swivel base is in the neutral position, is swiveling from the neutral position in the forward direction, is swiveling from the neutral position in the reverse direction, and the swivel limit is in the forward or reverse direction. Each of the positions is judged. On the other hand, each key play has normally open and normally closed contacts, and the connection state of each contact is reversed between the set state and the reset state, and unless the reset signal is input, the key play state is set mechanically. The reset signal is output only when the neutral detection switch is activated. Therefore, even if the controller is de-energized when the swivel is in any swivel position other than the neutral position, the keep relay keeps the state before the power failure. The turning state of the swivel base can be correctly known.

[0011]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show an embodiment in which the present invention is applied to an aerial work vehicle (work vehicle). In FIG. 4, the aerial work vehicle has a swivel base 2 which is capable of swiveling in a horizontal plane on a rear upper surface of a vehicle body 1, supports a boom 3 which extends and contracts on the swivel base 2 in a hoistable manner, and a tip of the boom 3 The workbench 4 is provided in the The swivel base 2 is rotatably supported with respect to the vehicle body 1, and as shown in FIG. 2, a hydraulic motor 5 (driving source) provided on the vehicle body 1 side enables swivel drive in both forward and reverse directions. There is. In FIG. 2, 6 is a drive gear attached to the hydraulic motor 5, and 7 is a turning gear which is integral with the turning base 2 and meshes with the driving gear 6.

The swivel base 2 has a forward direction (clockwise as viewed from above) and a reverse direction (counterclockwise) when the boom 3 extends forward along the center axis of the vehicle body to a neutral position. Each can turn 270 °. In FIG. 2, the hydraulic motor 5 is switched to each of the forward rotation, reverse rotation, and stop states by controlling the hydraulic oil fed from the hydraulic pump 9 with the control valve 10. In the control valve 10, when the central port state in the figure is set to the neutral position and switched to the lower port state, the hydraulic motor 5 is driven to rotate the swivel base 2 in the forward direction, and conversely to the upper port state. The hydraulic motor 5 is driven to reverse the swivel base 2. Reference numeral 11 is a rotary joint that connects the hydraulic passages so that hydraulic fluid can flow in and out of the swivel portion.

A turning restriction mechanism is provided in order to prevent the turning base 2 from being driven beyond the turning limit. This is a restriction control valve 12 that acts on the above hydraulic control system to forcibly stop the hydraulic motor 5, a control device 13 that switches the port state of the restriction control valve 12, and three pieces that detect the swing angle of the swivel base 2. Limit switches L1 to L3 and switch dogs d1 to d3 for turning on the limit switches L1 to L3.

In FIG. 2, the regulation control valve 12 is connected to the pilot passage 14 of the control valve 10, and normally shuts off the bypass passage 16 that connects the pilot passage 14 and the drain passage 15. When the swivel base 2 reaches either the forward or reverse swing limit, the control device 13 operates to connect the bypass passage 16 and open the pilot passage 14 to return the control valve 10 to the neutral position and drive the hydraulic motor 5. To stop.

The switch dogs d1 to d3 are fixed to the outer surface of the ring 17 fixed to the lower part of the swivel base 2 by shifting the phase by 90 ° in the circumferential direction (see FIG. 3) and in a state in which the vertical positions are different. There is. The three limit switches L1 to L3 are arranged facing each other in the center of the rear peripheral surface of the ring 17 in a vertically stacked state, and are turned on only by the corresponding switch dogs d1 to d3.

In the control device 13, only the circuit portion related to the control of the regulation control valve 12 is shown in FIG. In FIG. 1, 19 is an in-vehicle battery, 20 is an ignition key switch, and R1 is a detection operation of a forward rotation limit switch L1 (limit switch) for detecting that the swivel base 2 has reached a swing limit position in the forward and reverse directions. The first keep relay, R2, which operates based on this, is the second keep relay, R3, which operates based on the detection operation of the reverse rotation limit switch L3 (limit switch) that detects that the swivel base 2 has reached the reverse rotation limit. R4 is a relay having a normal structure, and the above-mentioned members are connected as shown in FIG. The limit switch L2 functions as a neutral detection switch that detects that the swivel base 2 is in the neutral position. Both keep relays R1 and R2 have normally closed contacts r1c and r2c and normally closed contacts r1o and r2o, respectively, so that the state of each contact is reversed between the set state and the reset state (state in FIG. 1). It Further, both keep relays R1 and R2 are reset only when the limit switch L2 serving as the neutrality detection switch is turned on and the reset signal is input, and otherwise the set relays are kept maintained.

Next, the operation of the turning restriction mechanism will be described with reference to FIGS. 5 and 1. When the swivel base 2 is positioned in the neutral position, the neutral detection switch L2 comes into contact with the switch dog d2 and is turned on, as shown in FIGS. 5 (a) and 5 (d). In this state, both keep relays R1 and R2 are reset, so that the control device 13 can determine that the swivel base 2 is in the neutral position.

For example, when the swivel base 2 swivels in the forward rotation direction from the neutral position of FIG. 5A and the swivel angle reaches 90 ° as shown in FIG. 5B, the switch dog d3 causes the reverse rotation limit switch. Switch L3 is turned on. As a result, the second keep relay R2 is switched to the set state, and the normally closed and normally open contact states are switched to the states opposite to those in FIG. That is, the normally closed contact r2c between the forward rotation limit switch L1 and the first keep relay R1 is opened, and the normally open contact r2o between the forward rotation limit switch L1 and the relay R3 is closed to form a standby state. .. By changing the state of the second keep relay R2, the control device 13 can determine that the swivel base 2 has swung to the forward rotation region side and has swung 90 ° in the forward rotation direction.

From this state, the swivel base 2 further swivels, and when the swivel angle reaches 270 ° as shown in FIG. 5C, the switch dog d1 turns on the forward rotation limit switch L1. As a result, the relay R3 is excited, and its contact (not shown) is closed to switch the port state of the regulation control valve 12 to release the pressure in the pilot passage 14 and return the control valve 10 to the neutral position. Therefore, the hydraulic motor 5 is stopped, preventing the swivel base 2 from further turning. The first keep relay R1 does not operate because the normally closed contact r1c leading to the first keep relay R1 is opened. When the control valve 10 is operated to switch the normal / reverse rotation switch (not shown) to the reverse rotation side, the circuit between the control device 13 and the regulation control valve 12 is turned off in response to this switch signal. Therefore, the pressure in the pilot passage 14 returns to a normal state, and the port state of the control valve 10 can be switched to the reverse rotation side.

When the swivel base 2 rotates in the reverse direction, the switch dog d3 turns on the reverse rotation limit switch L3 during the reverse rotation, but the state of the second keep relay R2 does not change. When the swivel base 2 further swivels in the reverse direction and the neutral detection switch L2 is turned on by the switch dog d2, a reset signal is given to both the key relays R1 and R2 to return to the reset state.

When the swivel base 2 turns in the reverse rotation direction from the state shown in FIG. 5D, first, the switch dog d1 turns ON the forward rotation limit switch L1 as shown in FIG. 5E. As a result, the first keep relay R1 is switched to the set state, and the normally closed contact r1c between the reverse rotation limit switch L3 and the second keep relay R2 is opened. Further, the normally open contact r1o leading to the relay R4 is closed to form a standby state. After this state, when the reverse rotation limit switch L3 is turned on by the turning of the swivel base 2 as shown in FIG. 5 (f), the relay R4 is excited, so the contact outside the figure is closed and the regulation control valve is closed. By switching the 12 port states, the hydraulic motor 5 can be stopped in the same manner as when the forward rotation limit is reached. In order to return the swivel base 2 from the rotation limit to the normal rotation direction, in the same way as returning from the normal rotation limit to the reverse rotation direction, the control valve 10 is operated to switch the forward / reverse rotation switch to the forward rotation side to perform the regulation control. The valve 12 is returned to the state of FIG.

In the above embodiment, the limit switches are used as the switches L1 to L3 for detecting the turning angle, but the switches are not necessarily required and other switches such as a proximity switch and a photo switch are applied. You can also

In addition to the boom, the present invention can be applied to a work vehicle equipped with a ladder on a swivel base.

Further, in the above embodiment, the hydraulic motor 5 is forcibly stopped by opening the bypass passage of the control valve 10, but the control valve 10 is directly operated or the hydraulic pump 9 and the control valve 10 are connected. It is also possible to stop the hydraulic motor 5 by bypassing the pressurized hydraulic oil passage between them to the drain passage.

[0025]

[Effect of the device]

 As described above, according to the present invention, the neutral detection switch, the forward rotation limit switch, and the reverse rotation limit switch can be used to restrict the swing of the swivel base that swivels 360 ° or more. Compared to the conventional device that uses the angle detector to control the turning, the cost of the turning control mechanism can be reduced. In addition, the work of the drive source for the swivel base will be controlled by the keep relay that keeps the set state mechanically, and even if the work is interrupted during the turn and the power supply to the control device is stopped, a power failure will occur. By keeping the same state as before with the keep relay, it is possible to restart the operation of the swivel base and at the same time to know the swivel state correctly, and the swivel base turns excessively or the moment limiter is incorrect. It is possible to eliminate the abnormal operation such as the operation of the work vehicle and improve the safety of the work vehicle equipped with the turntable.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a main part of a control device for a turning restriction mechanism according to an embodiment of the present invention.

FIG. 2 is a system explanatory view showing a turning regulation mechanism.

FIG. 3 is a plan view showing a layout of switch dogs and switches.

FIG. 4 is a schematic side view of a work vehicle.

FIG. 5 is an explanatory diagram showing an operating state of each switch that detects a turning angle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Car body 2 ... Revolving base 3 ... Boom 5 ... Hydraulic motor (driving source) 12 ... Regulator control valve 13 ... Control device L1 ... Forward rotation limit switch L2 ... Neutral detection switch L3 ... Reverse rotation limit switch R1, R2 ... Keep relay

Claims (1)

[Scope of utility model registration request] 1. A swivel mounted on a vehicle body so as to be swivelable,
In a work vehicle equipped with a drive source that rotationally drives a swivel and a control device that controls the operating state of the drive source, neutral detection that detects that the swivel is in a neutral position between the swivel and the vehicle body A switch and a forward rotation limit switch that detects that the swivel has reached the rotational limit position in the forward rotation direction,
A reversing limit switch for detecting that the revolving base has reached the revolving limit position in the reverse rotation direction is provided, and the control device, based on the state change of each switch, the revolving base moves the revolving limit position in the forward rotation direction or the reverse rotation direction. The key relay that is configured to stop the output of the drive source in the state of reaching the limit and that operates based on the limit detection operation of the forward rotation limit switch and the key relay that operates based on the limit detection operation of the reverse rotation limit switch. A swivel control device for a work vehicle, comprising: