Classification and development of the hottest auto

2022-10-24
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Classification and development of automotive electrical switches

although the action principle of automotive electrical switches (hereinafter referred to as switches) is similar to that of ordinary electrical switches, automotive switches have certain particularity compared with ordinary electrical switches because they are switches that control various control device circuits on automobiles, their control objects are different, and their operation methods are also diverse

I. main features

1 On the premise of ensuring good performance, not only the appearance should be beautiful, but also the color of the surface must be coordinated with the tone of the interior parts of the whole vehicle, so as to improve the beauty of the whole carriage

2. Safety factors should be considered in the design. In case of an accident during driving, the vehicle should not cause personal injury to the passengers, or reduce the degree of injury to the minimum. For example, the buttons are designed into rounded corners, the length of the plate handle is shortened as far as possible, and the switch is fixed and embedded in the interior of the panel. In addition, the fire safety of vehicles must be considered, and the materials used for switches should be flame retardant materials

3. The external shape design of automobile switch must consider the installation position, operation mode, operation feeling and other factors. It is necessary to design and arrange according to the theory of ergonomics

4. The voltage levels include 6V (motorcycle), 12V (car) and 24V (diesel car). In the 21st century, the voltage level of 42V may also appear on cars

5. According to the different control objects, its working mode has three working states: instantaneous, short-time and continuous operation. According to different applications, the load current can range from lma-1000a

6. In consideration of reliability, automotive switches, like other automotive parts, will always be impacted and vibrated by forces in all directions during vehicle driving, resulting in early damage and loose riveting of switch parts. In addition, the vehicle will also be affected by the temperature, relative humidity and other harsh environment during operation, causing the oxidation of switch contacts to intensify, resulting in the shortening of switch life

II. Classification of automobile switches

there are many kinds of automobile switches, which can be introduced from two aspects: functionality and structure

classification by function:

1 Driving operation function: the varieties include ignition start, constant speed, overspeed, rearview mirror control switch, etc. The controlled loads include motors, relays, lamps, circuits, etc

2. Alarm signal function: varieties include steering horn, stop lamp, alarm lamp, brake lamp switch, etc. The controlled loads include lamps, relays, solenoid valves, etc

3. Functions of lighting system: varieties include headlamp, fog lamp, instrument lamp, switch, etc. The load controlled is mainly lamps

4. Functions of wiper system: there are wiper, washer, windshield heating switch, etc. The controlled loads include motors, relays, resistors, pumps, etc

5. Functions of air conditioning cooling system: varieties include fans, air conditioners, temperature control switches, etc. The controlled loads include motors, solenoid valves, etc

6. Functions of door, window and lock system: the varieties include door lock, electric window lifter, fuel tank cover, trunk, sunroof switch, etc. The controlled loads include motors, solenoid valves, etc

classified by mechanical structure:

since the 1950s, in order to meet the needs of automotive development, the structure of automotive switches has also changed greatly, mainly including the following seven types. Push pull type, rotary type, push rod type, burning plate type, button type, plate handle type, electronic type, etc

III. introduction to various switches

1 Push pull type: created in the 1940s and developed in the 1950s, it is widely used in cars and trucks. It mainly depends on the action of push and pull to complete the connection and disconnection of circuits. Some varieties also have bimetallic safety devices and light adjustment resistors (see Figure 1)

at present, it is only used on domestic buses and trucks. The utility model is characterized by simple structure and low price, and the disadvantages are large volume and large operation force. It is inconvenient to adjust the gear position when the vehicle is driving without drawing effect force

2. Rotary type: it mainly depends on the rotation of the main shaft to change the gear, so as to achieve the purpose of circuit on and off. There are many kinds of such switches. One is an ignition switch operated by a key, which is composed of a lock mechanism and a switch. The switch is fixed with a mounting nut. The specific outline is shown in Figure 2

the other is a switch with knobs of different shapes. For example, the switch that uses the round knob to control the angle of the rear-view mirror has been used in various models of Santana 2000 at present

3. Push rod type: the action principle of this kind of switch is relatively simple. The main reason is that under the action of the specified external force, the push rod moves in a straight line within a certain range to push the contact to close (or open). Once the external force disappears, it will automatically return by relying on its own reaction spring to keep the contact in its original state

this is a signal switch for doors and brake lights

at present, there are two types of brake light switch coordination in the braking system. One is that the brake light switch is combined with the oil (steam) circuit of the braking system. At present, trucks basically belong to this type. The other is that the brake light switch is separated from the braking system. This structure is mainly used in cars. The brake light switch is connected with the brake pedal by mechanical structure, such as the top bar brake light switch used in Santana cars. This variety has the following characteristics:

(1) the extension distance of the top bar can be adjusted in size within a certain range to meet the needs of the working stroke during braking

(2) two pairs of parallel contacts are used to ensure the reliability when the signal lamp is connected

(3) special measures have been taken in the structure and materials to ensure the reliability and durability of the products and ensure that the service life can reach more than 250000 times

4 Flexure plate: the main feature is that the working fulcrum is in the center and the working point is on both sides of the fulcrum. When one working face is pressed, the other working face is upward, like a seesaw

Since the 1980s, this type of switch has gradually sprung up and is widely used in buses and cars. There are also differences in its internal structure according to different uses

(1) common features:

a. the appearance is black and non reflective. The materials are generally black nylon 6 and nylon 66, but in recent years, white nylon materials are also used and the surface is sprayed with special black ink

b. according to international regulations, there are marks of different shapes on the switch button according to different switch functions. The marks can be formed in two ways: one is embedded in the button as an insert, and the other is laser engraving for the buttons sprayed with black ink

c. in order to facilitate the vehicle to drive at night, there are also luminous indications of different colors on the mark. There are two kinds of light sources: one is a miniature bulb, and the other is a light-emitting diode. Due to the improvement of the luminous rate and service life of the light-emitting diode in recent years, there is a trend to gradually replace the bulb

d. snap rings are equipped at both ends around, which is convenient for installation on the instrument panel

(2) switch classification: it can be divided into two categories: with automatic reset and without automatic reset:

a. with automatic reset: the basic feature is that the switch is in working state under the action of general plastic force that is expected to replace the existing difficult to degrade in many fields. Once the external force disappears, it can be reset automatically. At present, it is mainly used for the switch of car window lifter. The power of its contact must meet the current value

b. without automatic reset: this switch can have one or two gears, and the difference between the two is the difference in the number of controlled circuits after being connected

5. Electronic type: switches that use electronic components to control automobile circuits have been gradually applied. This type of switch has no contacts, so there is no fault caused by contact ablation. At present, the typical product is electronic dimmer switch. It is mainly composed of two parts, namely, the flexible plate switch and the electronic dimming system (voltage regulation can be completed by using an adjusting knob on the switch surface)

electronic dimming eliminates the defect that the wire wound resistance fails due to the long-term power on and heating state of the resistance and acceleration

in addition, the electronic dimming system also adds load overcurrent protection facilities

6. Button type: this type of switch is commonly known as push switch, which can be divided into two types: without self-locking and with self-locking. The former has simple structure and is rarely used at present. The planar button type switch with self-locking has become popular in cars since the mid-1980s. Its main features are beautiful appearance and simple operation. This brings convenience to the driver's operation safety when the vehicle is running

the switch is currently used in Shanghai GM "Buick", Shanghai Volkswagen "Passat", DPCA "Fukang" and other models

7. Plate handle type: the plate handle type switch mainly uses the action principle of lever to achieve the control purpose. The typical variety is the currently popular combination switch

due to the different structures of electrical control circuits selected by automobile manufacturers in various countries, the control methods adopted are also different, which can be divided into two categories:

first, direct control type: that is, the combination switch directly controls the load. This requires that the contact of the switch can bear large power, and the power of the controlled object is different

the second is the gap control type: its feature is that the combined switch does not directly control the load, but controls the intermediate relay, and then uses the contact of the intermediate relay to control the load. Therefore, the contact power requirements of the combined switch are small, and the power of the control object is basically the same

we should distinguish the above differences, otherwise it will cause accidents. In addition, when affirming the advantages of the combined switch, we can't ignore its shortcomings. Because the objects controlled by the two handles of the combined switch are different, the use frequency will be inconsistent in use. Relatively speaking, the handle with dimming and steering functions has a higher use frequency than the handle with wiping and washing functions. Of course, the damage is also fast, which will cause the damage and failure of the whole switch, which is very inconvenient even if it can be repaired, Therefore, at present, the combination switch on some cars has made great improvements in its structure, that is, it adopts the "independent assembly module combination", that is, the three components of the two handles and the ignition switch are relatively independent, and then jointly assembled on the steering column to form a unified combination switch. In case of damage to one component, it can be easily replaced without affecting the integrity of other components. At present, the combination switch of Shanghai Volkswagen's "Passat" car belongs to this type

at present, typical combination switches have the following functions:

category

name

function

light

dimmer switch

turn signal switch

stop light switch

low beam, high beam, overtaking signal

off, left, right, automatic return, lane change

off, left, right (ignition lock is disconnected)

power consumption control

wiper switch

washing should be carried out comprehensively Multi level energy-saving technology reformer switch

horn button contact

off, low speed, high speed, gap, short

off, on

off, on

power control

ignition switch

lock, on, ignition, start

anti theft mechanism

steering lock

unlock, lock, insurance

(end)

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