Control circuit for preventing flameout electromagnetic valve from being powered on during secondary start for micro-excavation

Abstract

The utility model relates to the field of engineering machinery, in particular to a control circuit for preventing energization of a flameout electromagnetic valve during secondary start for micro-excavation, which comprises a key switch and the flameout electromagnetic valve, the flameout electromagnetic valve is provided with a pull-in coil and a holding coil, and the pull-in coil and the holding coil are respectively connected with a power supply to form a power supply loop. The key switch is installed on a power supply loop of the holding coil, a normally open contact of the flameout electromagnetic valve relay is connected to the power supply loop of the pull-in coil, and a coil of the flameout electromagnetic valve relay is connected with a power supply to form a power supply loop. The coil power supply loop of the flameout solenoid valve relay is provided with a starting protection relay which controls the normally open contact loop of the flameout solenoid valve relay to be disconnected when secondary starting misoperation occurs. According to the control circuit for preventing the flameout electromagnetic valve from being powered on during secondary starting for the micro-excavator, the situation that the pull-in coil is burnt due to long-time power-on can be avoided, and therefore the situation that the flameout electromagnetic valve fails is avoided.

Description

Technical Field

[0001] The utility model relates to the field of engineering machinery, in particular to a control circuit for a micro excavator which prevents a flameout electromagnetic valve from being energized during secondary starting. Background Art

[0002] An excavator is a type of engineering machinery widely used in earthwork construction. A bucket is provided on the front side of the excavator, and the bucket is connected to the excavator through a boom and an arm. A boom cylinder for controlling the movement of the arm is installed on the upper part of the boom. In addition, a boom cylinder for controlling the movement of the boom is also installed on the excavator. The boom cylinder is supplied with oil through the boom lifting oil circuit, and the boom lifting and falling are controlled by the boom cylinder; the movement of the bucket is controlled by the rocker arm cylinder, which is supplied with oil through the bucket retracting oil circuit, and the rocker arm rotation is controlled by the rocker arm cylinder, driving the bucket to complete the retracting and digging actions.

[0003] At present, the engine shutdown solenoid valve without ECU is divided into a pull-in coil and a holding coil. The current of the pull-in coil can reach more than 30A when it is working, and long-term operation will cause the coil to burn out. The shutdown solenoid valve with a built-in timing relay may fail due to high temperature. If there is an erroneous operation of secondary startup after failure, the pull-in coil of the shutdown solenoid valve may be energized, thereby burning the pull-in coil, which needs to be improved. Utility Model Content

[0004] The utility model aims to provide a control circuit for a micro excavator to prevent the burning of a suction and pulling coil and to prevent the solenoid valve from being energized during secondary starting.

[0005] To achieve the above-mentioned purpose, the utility model discloses a control circuit for preventing a flameout solenoid valve from being energized during secondary starting for a micro excavator, and the structural features of the control circuit are as follows: it includes a key switch, a power supply and a flameout solenoid valve, the flameout solenoid valve is provided with a suction and pull coil and a holding coil, the suction and pull coil and the holding coil are respectively connected to the power supply to form a power supply circuit, the key switch is installed on the power supply circuit of the holding coil, and also includes a flameout solenoid valve relay, the normally open contact of the flameout solenoid valve relay is connected to the power supply circuit of the suction and pull coil, the coil of the flameout solenoid valve relay is connected to the power supply circuit to form a power supply circuit, and a starting protection relay is installed on the coil power supply circuit of the flameout solenoid valve relay to control the normally open contact circuit of the flameout solenoid valve relay to be disconnected when the secondary starting is erroneously operated.

[0006] The instrument or controller determines the operating status of the engine by detecting the engine speed. When the engine is started, the start protection relay receives the start protection signal, and the controller continues to send a high-level signal, and the start protection relay is disconnected. At this time, even if there is a second start, the flameout solenoid valve relay will not be energized, and the flameout solenoid valve pull-in coil will not be energized; if the second start is operated incorrectly, even if the flameout solenoid valve timing relay fails due to high temperature, there is a possibility of continuous conduction, but because the vehicle wiring harness has no power supply to the flameout solenoid valve pull-in coil end, the pull-in coil will not be energized for a long time and then burned, thereby preventing the flameout solenoid valve from failing.

[0007] Preferably, the positive pole of the power source is connected to the start position of the key switch, and the negative pole of the power source is connected to the vehicle body.

[0008] Regarding the circuit connection structure of the ignition shutoff solenoid valve relay, one end of the coil of the ignition shutoff solenoid valve relay is connected to the ACC gear of the key switch, and the other end is connected to the vehicle body to form a power supply circuit.

[0009] One end of the coil of the start protection relay is connected to the start protection signal (the start protection signal comes from the controller, which is suspended or low level when the engine is not started, and continuously outputs high level after the engine is started), and the other end is connected to the vehicle body. One end of the controlled end of the start protection relay is connected to the start gear of the key switch, and the other end is connected to the coil of the ignition solenoid valve relay.

[0010] Regarding the circuit connection structure of the holding coil, one end of the holding coil is connected to the start position of the key switch, and the other end of the holding coil is connected to the vehicle body.

[0011] Regarding the circuit connection structure of the pull-in coil, one end of the pull-in coil is connected to the normally open contact of the ignition-off solenoid valve relay, and the other end of the pull-in coil is connected to the vehicle body.

[0012] To sum up, the beneficial effects of the utility model are: the instrument or controller determines the operating state of the engine by detecting the engine speed. When the engine is started, the start protection relay receives the start protection signal, and the controller continues to send a high-level signal, and the start protection relay is disconnected. At this time, even if there is a secondary start, the flameout solenoid valve relay will not be attracted, and the flameout solenoid valve pull-in coil will not be energized; if the secondary start-up is misoperated, even if the flameout solenoid valve timing relay fails due to high temperature, there is a possibility of continuous conduction, but because the vehicle wiring harness has no power supply to the flameout solenoid valve pull-in coil end, the pull-in coil will not be energized for a long time and then burned, thereby preventing the flameout solenoid valve from failing. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the circuit structure of the utility model.

[0014] In the figure: key switch 1, power supply 2, flameout solenoid valve relay 3, flameout solenoid valve 4, suction and pull coil 5, holding coil 6, start protection relay 7. DETAILED DESCRIPTION

[0015] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0016] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0017] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0018] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0019] The following is a description of preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0020] A control circuit for a micro excavator to prevent a flameout solenoid valve from being energized during secondary starting includes a key switch 1, a power supply 2, and a flameout solenoid valve 4. The flameout solenoid valve 4 is provided with a pull-in coil 5 and a holding coil 6. The pull-in coil 5 and the holding coil 6 are respectively connected to the power supply 2 to form a power supply circuit. The key switch 1 is installed on the power supply circuit of the holding coil 6. It also includes a flameout solenoid valve relay 3. The normally open contact of the flameout solenoid valve relay 3 is connected to the power supply circuit of the pull-in coil 5. The coil of the flameout solenoid valve relay 3 is connected to the power supply circuit of the power supply circuit. A start protection relay 7 is installed on the coil power supply circuit of the flameout solenoid valve relay 3 to control the normally open contact circuit of the flameout solenoid valve relay 3 to be disconnected when the secondary starting is erroneously operated. Refer to the attached Figure 1 , the instrument or controller determines the operating state of the engine by detecting the engine speed. When the engine is started, the start protection relay 7 receives the start protection signal, and the controller continues to send a high-level signal, and the start protection relay 7 is disconnected. At this time, even if there is a secondary start, the flameout solenoid valve relay 3 will not be attracted, and the flameout solenoid valve 4 suction and pull coil 5 will not be energized; if the secondary start-up is misoperated, even if the flameout solenoid valve 4 timing relay fails due to high temperature, there is a possibility of continuous conduction, but because the vehicle wiring harness does not have a power supply 2 connected to the flameout solenoid valve 4 suction and pull coil 5 end, the suction and pull coil 5 will not be energized for a long time and then burned, thereby preventing the flameout solenoid valve 4 from failing.

[0021] Refer to the attached Figure 1 , the positive pole of the power supply 2 is connected to the starting gear of the key switch 1, and the negative pole of the power supply 2 is connected to the vehicle body. Regarding the circuit connection structure of the flameout solenoid valve relay 3, one end of the coil of the flameout solenoid valve relay 3 is connected to the starting gear of the key switch 1, and the other end is connected to the vehicle body to form a power supply circuit. Regarding the circuit connection structure of the starting protection relay 7, the normally closed contact of the starting protection relay 7 is installed on the coil loop of the flameout solenoid valve relay 3. Regarding the circuit connection structure of the holding coil 6, one end of the holding coil 6 is connected to the starting gear of the key switch 1, and the other end of the holding coil 6 is connected to the vehicle body. Regarding the circuit connection structure of the pull-in coil 5, one end of the pull-in coil 5 is connected to the normally open contact of the flameout solenoid valve relay 3, and the other end of the pull-in coil 5 is connected to the vehicle body.

[0022] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A control circuit for preventing a flameout solenoid valve from being energized during secondary starting for a micro excavator, comprising a key switch (1), a power supply (2) and a flameout solenoid valve (4), characterized in that: The flameout solenoid valve (4) is provided with a pull-in coil (5) and a holding coil (6), the pull-in coil (5) and the holding coil (6) are respectively connected to a power supply (2) to form a power supply circuit, the key switch (1) is installed on the power supply circuit of the holding coil (6), and also includes a flameout solenoid valve relay (3), the normally open contact of the flameout solenoid valve relay (3) is connected to the power supply circuit of the pull-in coil (5), the coil of the flameout solenoid valve relay (3) is connected to the power supply circuit of the power supply circuit, and a start protection relay (7) is installed on the coil power supply circuit of the flameout solenoid valve relay (3) to control the normally open contact circuit of the flameout solenoid valve relay (3) to be disconnected when a secondary start-up error occurs.

2. The control circuit for preventing the solenoid valve from being energized during secondary starting for a micro excavator according to claim 1, characterized in that: The positive electrode of the power source (2) is connected to the start position of the key switch (1), and the negative electrode of the power source (2) is connected to the vehicle body.

3. The control circuit for preventing the solenoid valve from being energized during secondary starting for a micro excavator as claimed in claim 2, characterized in that: One end of the coil of the flameout solenoid valve relay (3) is connected to the start position of the key switch (1), and the other end is connected to the vehicle body to form a power supply circuit.

4. The control circuit for preventing the solenoid valve from being energized during secondary starting for a micro excavator as claimed in claim 3, characterized in that: The normally closed contact of the start protection relay (7) is installed on the coil loop of the flameout solenoid valve relay (3).

5. The control circuit for preventing the solenoid valve from being energized during secondary starting for a micro excavator as claimed in claim 2, characterized in that: One end of the holding coil (6) is connected to the ACC position of the key switch (1), and the other end of the holding coil (6) is connected to the vehicle body.

6. The control circuit for preventing the solenoid valve from being energized during secondary starting for a micro excavator according to claim 1, characterized in that: One end of the pull-in coil (5) is connected to the normally open contact of the flameout solenoid valve relay (3), and the other end of the pull-in coil (5) is connected to the vehicle body.

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