Heating device for cab of electric excavator

Abstract

The utility model discloses a heating device for a cab of an electric excavator, which comprises a refrigerating device, and the refrigerating device comprises a compressor circuit, a compressor, an air-conditioning fan, an electric heating device and a contactor, the electric heating device comprises an isolation transformer, a rectifier and an electric heater; the contactor comprises a normally closed switch, a first normally open switch, a second normally open switch and a switching coil; the normally closed switch is connected to a compressor circuit; the two ends of the switching coil are electrically connected with the ground wire and the warm air switch respectively, and the warm air switch is electrically connected with the control power source. The isolation transformer comprises a primary coil and a secondary coil; the primary coil is connected with an alternating current power supply through a first normally open switch and a second normally open switch; the secondary coil is electrically connected with an input contact of the rectifier, and the electric heater is electrically connected with an output contact of the rectifier; and the electric heater is arranged at an air outlet of the air conditioner fan. The heating function of the cab is achieved through electrical connection, the existing excavator does not need to be greatly modified, and existing equipment in the cab of the excavator is fully utilized.

Description

Technical Field

[0001] The utility model relates to the technical field of engineering machinery, in particular to a heating device for a cab of an electric excavator. Background Art

[0002] Due to prominent problems such as emissions from fuel excavators, relevant policies encourage the use of electric excavators, which use three-phase four-wire power. Excavators do not require fuel refueling and consumption, and related projects can achieve green construction.

[0003] However, fuel excavators can use the heat energy of the engine's coolant for air conditioning heating in winter. Electric excavators do not have hot water available because they use electric motors. In addition, most of the air conditioners on existing electric excavators are single-cooling air conditioners, which means the cab cannot be heated in winter. Utility Model Content

[0004] In view of the above-mentioned defects in the prior art, the purpose of the utility model is to provide a heating device for an electric excavator cab, which adds an electric heating device on the basis of the existing refrigeration device.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A heating device for an electric excavator cab comprises a refrigeration device, the refrigeration device comprises a compressor circuit, a compressor, an air-conditioning fan, and also comprises an electric heating device and a contactor; the electric heating device comprises an isolation transformer, a rectifier, and an electric heater; the contactor comprises a normally closed switch, a first normally open switch, a second normally open switch, and a switching coil, when the switching coil is turned on, the normally closed switch is disconnected, and the first normally open switch and the second normally open switch are closed and turned on; the normally closed switch is connected to the compressor circuit; the two ends of the switching coil are electrically connected to the ground wire and the warm air switch respectively, and the warm air switch is electrically connected to the control power supply; the isolation transformer comprises a primary coil and a secondary coil; the two ends of the primary coil are electrically connected to the live wire and the neutral wire of the AC power supply respectively through the first normally open switch and the second normally open switch; the secondary coil is electrically connected to the input contact of the rectifier, and the electric heater is electrically connected to the output contact of the rectifier; the electric heater is arranged at the air outlet of the air-conditioning fan.

[0007] Furthermore, the number of turns of the primary coil is greater than the number of turns of the secondary coil.

[0008] Furthermore, the electric heating device also includes a capacitor, and the capacitor is connected in parallel with the electric heater.

[0009] Furthermore, a first fuse is arranged on the live wire of the AC power source, and a second fuse is arranged between the secondary coil and the rectifier.

[0010] Furthermore, the output power of the isolation transformer is greater than 1.2 times the power of the electric heater; and the isolation transformer is arranged outside the cab of the excavator.

[0011] Furthermore, the output voltage of the rectifier is less than 36V.

[0012] Furthermore, the external dimensions of the electric heater are the same as the dimensions of the air outlet of the air conditioner fan.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] The utility model realizes the heating function of the cab by using electrical connection, does not need to make major operation transformation on the existing excavator, and fully utilizes the existing equipment in the excavator cab. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The utility model is a structural schematic diagram of a heating device for an electric excavator cab.

[0016] In the figure: 1. Contactor; 2. Heater switch; 3. Isolation transformer; 3.1. Primary coil; 3.2. Secondary coil; 4. Compressor; 5. Rectifier; 6. Capacitor; 7. Electric heater; 8. Air conditioning fan; 9. First fuse; 10. Second fuse. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] Embodiment 1:

[0019] See also Figure 1 The utility model provides a heating device for an electric excavator cab, which adds an electric heating device on the basis of an existing refrigeration device, and controls the switching of the two through a contactor 1. The refrigeration device includes a compressor circuit, a compressor 4, and an air-conditioning fan 8. The electric heating device includes an isolation transformer 3, a rectifier 5, a capacitor 6, and an electric heater 7.

[0020] The contactor 1 includes a normally closed switch, a first normally open switch, a second normally open switch, and a switching coil. The gate rods of the normally closed switch, the first normally open switch, and the second normally open switch are connected and can be attracted by the magnetic force generated by the switching coil. The contactor realizes the interlocking of the heating device and the cooling device to prevent both from being turned on at the same time.

[0021] The normally closed switch is connected to the compressor circuit;

[0022] The C contact of the first normally open switch is electrically connected to the live wire of the AC power source B1;

[0023] The A contact of the second normally open switch is electrically connected to the neutral line of the AC power source B1;

[0024] The M contact and N contact of the switching coil are electrically connected to the ground wire and the control power supply B2 respectively. A warm air switch 2 is arranged between the control power supply B2 and the N contact. When the warm air switch 2 is closed, the switching coil is turned on, the normally closed switch moves down and is interrupted, and the first normally open switch and the second normally open switch move down and are turned on.

[0025] The isolation transformer 3 includes a primary coil 3.1 and a secondary coil 3.2. The number of turns of the primary coil 3.1 is greater than that of the secondary coil 3.2. The isolation transformer 3 plays a voltage-reducing role, so that the voltage of the AC power supply B1 is reduced to the working voltage of the electric heater 7.

[0026] The M contact of the primary coil 3.1 is electrically connected to the D contact of the first normally open switch;

[0027] The N contact of the primary coil 3 . 1 is electrically connected to the B contact of the second normally open switch.

[0028] The rectifier 5 includes four diodes, which are connected in sequence in a group of two. The two groups are connected at the head and tail. A contact is set between every two diodes, with a total of four contacts. The contacts in the group are R contacts and T contacts, which serve as input contacts. The contacts between the groups are Q contacts and S contacts, which serve as output contacts. The contact at the head intersection is the positive electrode. Figure 1 The S contact is the head intersection point, and the Q contact is the tail intersection point;

[0029] The R contact of the rectifier 5 is electrically connected to the O contact of the secondary coil 3.2;

[0030] The T contact of the rectifier 5 is electrically connected to the P contact of the secondary coil 3 . 2 .

[0031] The electric heater 7 is arranged at the air outlet of the air conditioner fan 8, and such arrangement does not require changing the structure of the air conditioner itself, and only requires adding an additional heater;

[0032] The U contact of the electric heater 7 is electrically connected to the S contact of the rectifier 5, and the V contact of the electric heater 7 is electrically connected to the Q contact of the rectifier 5. The rectifier 5 converts the AC power into pulsating DC power and supplies it to the electric heater 7 for heating.

[0033] The capacitor 6 is connected in parallel with the electric heater 7 , and the capacitor 6 can smooth the pulsation curve of the pulsating direct current and improve the efficiency of the rectifier 5 .

[0034] Specifically, a first fuse 9 is provided on the live wire of the AC power source B1, and a second fuse 10 is provided between the C contact of the secondary coil 3.2 and the R contact of the rectifier 5 as overload protection.

[0035] Specifically, the output power of the isolation transformer 5 is greater than 1.2 times the power of the electric heater 7 to prevent the isolation transformer from overheating; at the same time, the isolation transformer 5 is set outside the excavator cab, and the heating is turned on only under cold conditions, so as to use the cold environment to cool the isolation transformer 5 and further prevent the isolation transformer 5 from overheating.

[0036] Specifically, the output voltage of the rectifier 5, ie, the voltage between the contact Q and the contact S, is less than 36V.

[0037] Specifically, the outer dimensions of the electric heater 7 match the dimensions of the air outlet of the air-conditioning fan 8, so that the wind force of the air-conditioning fan can be optimally utilized.

[0038] It should be noted that the refrigeration device is a component of the electric excavator itself, so it will not be described in detail. Its working method and internal structure are known to those skilled in the art.

[0039] Embodiment 2:

[0040] Based on Example 1, this example provides a working process of a heating device for an electric excavator cab:

[0041] When the heater switch 2 is closed, the control power supply B2 of the excavator reaches the switching coil of the contactor 1 through the heater switch. Current flows through the switching coil, the first normally open switch and the second normally open switch of the contactor 1 are closed and turned on, and the normally closed switch is opened and interrupted, disconnecting the connection between the compressor 4 and the compressor circuit, thereby realizing the interlocking of the heating function and the cooling function.

[0042] The AC power supply B1 of the excavator passes through the first fuse 9, the first normally open switch, the second normally open switch, and enters the primary coil 3.1 of the isolation transformer 3. After being stepped down in the secondary coil 3.2, it passes through the second fuse 10, and is rectified into pulsating direct current in the rectifier 5. It is then filtered by the capacitor 6 to become a stable direct current. Current passes through the electric heater 7 to perform the heating function, and hot air is blown out through the air-conditioning fan 8 of the excavator to realize the heating function of the cab in winter.

[0043] All components and connection methods of components not discussed in this application belong to the known technologies in this technical field and can be directly applied without further explanation.

[0044] In the present invention, the term "plurality" means two or more than two, unless otherwise clearly defined. The terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0045] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0046] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0047] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A heating device for an electric excavator cab, comprising a refrigeration device, wherein the refrigeration device comprises a compressor circuit, a compressor, and an air conditioning fan, wherein: It also includes electric heating devices and contactors; The electric heating device includes an isolation transformer, a rectifier, and an electric heater; The contactor comprises a normally closed switch, a first normally open switch, a second normally open switch, and a switching coil, wherein the gate rods of the normally closed switch, the first normally open switch, and the second normally open switch are connected and can be attracted by the magnetic force generated by the switching coil; The normally closed switch is connected to the compressor circuit; The two ends of the switching coil are electrically connected to the ground wire and the heating switch respectively, and the heating switch is electrically connected to the control power supply; The isolation transformer comprises a primary coil and a secondary coil; The two ends of the primary coil are electrically connected to the live wire and the neutral wire of the AC power supply through a first normally open switch and a second normally open switch respectively; The secondary coil is electrically connected to the input contact of the rectifier, and the electric heater is electrically connected to the output contact of the rectifier; The electric heater is arranged at the air outlet of the air conditioner fan.

2. The heating device for the cab of an electric excavator according to claim 1, characterized in that: The number of turns of the primary coil is greater than the number of turns of the secondary coil.

3. The heating device for the cab of an electric excavator according to claim 1, characterized in that: The electric heating device further comprises a capacitor, which is connected in parallel with the electric heater.

4. The heating device for the cab of an electric excavator according to claim 1, characterized in that: A first fuse is arranged on the live wire of the AC power source, and a second fuse is arranged between the secondary coil and the rectifier.

5. The heating device for the cab of an electric excavator according to claim 1, characterized in that: The output power of the isolation transformer is greater than 1.2 times the power of the electric heater; The isolation transformer is arranged outside the cab of the excavator.

6. The heating device for the cab of an electric excavator according to claim 1, characterized in that: The output voltage of the rectifier is less than 36V.

7. The heating device for the cab of an electric excavator according to claim 1, characterized in that: The external dimensions of the electric heater are the same as the dimensions of the air outlet of the air conditioner fan.

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