JP2011235858A - Accelerator pedal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease such a chance that a resin component of an electronic accelerator pedal device is electrified to cause failure.SOLUTION: In recent years, the number of the resin components adopted in the electronic accelerator pedal device is increased, but since a resin has high insulation properties, the resin is electrified easily to accumulate an electric charge when rubbed or contacted. Thus, the electric charge generated by the friction of a friction member inside the accelerator pedal device, the electric charge generated by the friction between the shoe of a driver and an accelerator pedal, and the electric charge generated in a vehicle, or the like flow into and are accumulated in the resin component. The electric charge accumulated in such a way intrudes into a position sensor as an overvoltage, and has a possibility of causing the failure such as rapid acceleration of the vehicle. Therefore, an antistatic resin having a function of leaking the electric charge is used for decreasing the change to cause the failure.

Description

  The present invention relates to an electronic accelerator pedal device that is applied to a vehicle that employs a system that detects depression of an accelerator pedal by a sensor and electronically controls a driving force. As long as it is electronically controlled through an electronic accelerator pedal, it can be applied regardless of the form and type of vehicle and driving force. In addition to vehicles, trains, ships, airplanes, rockets, etc. that already exist, vehicles that will be newly developed in the future are also applied. As a power source for generating motive power, the present invention is also applied to a power source that is newly developed in the future in addition to an existing one such as an internal combustion engine, an electric motor, a jet engine or a rocket engine.

  Attempts to electronically control vehicles began with the introduction of fly-by-wire systems in the field of aircraft. The pilot's operation is transmitted to the hydraulic actuator through the flight control computer through an electrical circuit. The link connected to the actuator has been abolished and the weight has been reduced, and there has been an advantage that control for preventing dangerous flight can be incorporated into the computer. With the advancement of computers, complex and precise control has become possible, and electronic control has become widespread in vehicles other than aircraft. Accordingly, the introduction of an electronic accelerator pedal device is progressing as a means for controlling the driving force.

  With regard to vehicles, electronic control and electronic accelerator pedals are being introduced regardless of the type of power source such as an internal combustion engine or an electric motor. This is because the electronically controlled throttle system enables precise and accurate control of the internal combustion engine through a computer, as compared with a conventional mechanically controlled throttle system. Similarly, electronic accelerator pedals are being introduced as means for precisely controlling the torque of electric motors. Hybrid vehicles and electric vehicles equipped with electric motors, which are highly effective in reducing carbon dioxide emissions, are on the rise, and the installation rate of electronic accelerator pedals essential for electronic control is expected to increase in the future.

  The electronic accelerator pedal device includes a pedal arm that swings when a driver's stepping force is applied, a position sensor that detects the amount of pedal arm depression, an electrical component attached thereto, and a spring that adds a return force to the pedal arm stepping. A friction member that adds sliding resistance in accordance with the swing of the pedal arm, a pedal shaft that is a shaft on which the pedal arm swings, a pedal plate that is in contact with the driver's foot at the end of the pedal arm, and supports them It consists of members.

  In a conventional mechanical accelerator pedal device, a metal part is employed because it has a link mechanism. However, in the electronic accelerator pedal device, the link mechanism has been abolished, and in recent years, the adoption of resin parts has been progressing due to the need for high weight and rust prevention treatment and the high price of materials having rust prevention effect. . Compared to metal parts, there are advantages such as higher degree of freedom in molding, easy assembly, and reduced part cost. In addition to the friction member, a pedal arm, a pedal shaft, a pedal plate, a support member, and the like are increasingly used as an integrated module using resin. Polypropylene, polyethylene, etc. are used as the resin material, and they are designed and processed to have strength and durability comparable to metal parts.

  However, since the resin has high insulating properties, it has a drawback that it is easily charged by friction and contact and accumulates electric charges. When the friction member is a resin, it is strongly charged by being pressed and rubbed as it swings, and charges are accumulated inside the accelerator pedal. When electric power is supplied to the position sensor through a circuit, electric charge may leak and accumulate in the resin component that is in contact with the position sensor or the circuit. In addition, the accelerator pedal is placed in an environment where static electricity is likely to be generated around the accelerator pedal and it is easy for them to flow. Due to the vibration of the vehicle during driving, electric charges are generated in the driver and the seats and seat belts in contact with the driver, and the driver is charged and the electric charges flow into the pedal plate / pedal arm through the shoes under the feet. Electric charge is generated and flows by friction and contact between the driver's shoes and the pedal plate. Static electricity generated from electronic devices such as an internal combustion engine and a control computer during operation also flows as electric charges. Static electricity is also generated from high-power electric motors mounted on electric cars and hybrid cars, and electric charge flows through the driver and body. Under such circumstances, when an ordinary resin part having a high surface specific electrical resistance value is provided, it is inevitable that charges are always accumulated in the accelerator pedal device.

  If electric charges accumulate in the resin parts, the following problems may occur in the accelerator pedal device, which may cause serious problems related to safe driving. 1) Enters the position sensor or electric circuit as an overvoltage, destroys the position sensor and disables operation. 2) It penetrates into the position sensor and the electric circuit as an overvoltage and sends an unintended electric signal to the computer to cause sudden acceleration of the vehicle contrary to the intention. 3) The pedal arm does not swing, causing a return failure and the accelerator pedal is depressed, contrary to the driver's intention.

JP 2004-155373 A

Supervised by Kiyoshi Akamatsu Technology and application of antistatic materials CM Publishing 2002

  The problem to be solved by the present invention is that, in an electronic accelerator pedal device provided with resin parts, a failure occurs due to accumulation of electric charge in the resin.

  Patent document 1 precedes as a countermeasure against static electricity of the electronic accelerator pedal device. In order to prevent the position sensor from being destroyed when the electric charge charged to the driver flows into the resin pedal arm through the feet, a technology for providing a ground path between the pedal arm and the body to leak the electric charge Proposed in the gazette.

  However, in the case of a highly insulating material such as a resin, unlike a conductive material such as a metal, even if a ground path is provided, the charge does not leak and the accumulated state continues, so this measure cannot be fully effective. . Therefore, in order to effectively prevent the charge from being accumulated in the resin, it is necessary to provide an antistatic resin having a function of leaking the charge. Although it is desirable that all the resin parts are provided with an antistatic resin, in order to operate the position sensor normally, the resin parts for ensuring the insulation of the electric circuit must be excluded.

  By providing the resin component constituting the accelerator pedal device with the antistatic resin, the charge is likely to leak quickly. Even if the friction member rubs, it becomes difficult to accumulate electric charge, and even if electric charge charged to the driver or electric charge generated from the electronic equipment or power source of the vehicle flows in, the electric charge leaks quickly and accumulates inside. It becomes difficult. Therefore, when driving a vehicle, the possibility of the following failure occurring in the electronic accelerator pedal device is reduced, which helps to improve safety during driving. 1) Enters the position sensor or electric circuit as an overvoltage, destroys the position sensor and disables operation. 2) It penetrates into the position sensor and the electric circuit as an overvoltage and sends an electric signal not intended by the driver to the computer, causing sudden acceleration of the vehicle contrary to the intention. 3) The pedal arm does not swing, causing a return failure and the accelerator pedal is depressed, contrary to the driver's intention.

FIG. 1 is an exploded perspective view showing an embodiment of an electronic accelerator pedal device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which an accelerator pedal is provided with resin for all the constituent members except that the position sensor 8 and the electric parts attached thereto, the spring 7 and the fastening screw are provided with metal parts. It is a module. Although the content of embodiment is described below, this invention is not limited only to this embodiment, It is applied to the Example of an electronic accelerator pedal apparatus provided with the resin component of another different aspect.

  The pedal arm 1 swings around the pedal shaft 2 in response to the driver's stepping on the foot, and a pedal plate 3 is bonded to the end. The spring 7 is attached to the end opposite to the pedal plate 3 and applies a restoring force to the depression of the pedal arm 1. The friction plate 6 is welded so as to cover the pedal shaft 2 and rubs against the fixing plate 5 on the housing 4 side as a support member to generate a sliding resistance. The fixed plate 5 is also a bearing member that supports the petal shaft 2. The position sensor 8 senses the position of a magnet mounted in the pedal shaft 2 and outputs an electrical signal to the connector 9 through an electrical circuit 10. The connector 9 is connected to an external control computer by an electrical circuit, supplies power to the position sensor 8 through the electrical circuit 10, and transmits an electrical signal from the position sensor 8. In order to simplify the drawing, the fastening screws are omitted.

  As a mechanism peculiar to the electronic accelerator pedal device, there is a sliding resistance adding mechanism. This is provided to keep the accelerator operation amount at a desired value even if the driver's stepping force fluctuates somewhat. An electronic control system that detects the amount of accelerator depression with a sensor and controls the throttle opening based on this sensor uses a linkless system that eliminates the link between the actuator that moves the throttle valve and the accelerator pedal. It has been. In this case, the accelerator pedal and the actuator are connected only by an electric circuit, and the load when operating the actuator is not transmitted to the accelerator pedal through the link as in the conventional case. By adding a sliding resistance to replace the load, the stepping force required for the driver to maintain the desired pedal position is reduced, and the accelerator operation is stabilized.

  As a sliding resistance adding mechanism, a mechanism including a resin friction member that interlocks with swinging around the axis of a pedal arm is widely used. As the friction member, for example, a resin material having wear resistance such as nylon, polyacetal, polybutylene terephthalate or the like is employed. Although there are many examples of different modes, in the embodiment of the present invention, when the driver depresses the accelerator pedal, the fixed plate 5 provided on the housing 4 side in accordance with the swing of the pedal arm 1; The friction plates 6 provided on the pedal arm 1 side are pressed against each other and rubbed to generate sliding resistance.

  Since the friction member has a high degree of friction, the friction member generates and accumulates a lot of electric charge. When a large amount of charge is accumulated in the resin friction member, the friction member (the friction plate 6 and the fixed plate 5 in the embodiment of the present invention) attracts by the Coulomb force generated by the charge and adheres against the restoring force of the spring. In addition, the pedal arm may not swing. In this case, the accelerator pedal may be depressed against the driver's intention, which is dangerous for safe driving. In addition, charges may flow into the position sensor and cause a failure.

  In the embodiment of the present invention, the provided basic resin materials are classified into the following five types. 1) Nylon constituting the friction plate 6. 2) Styrene butadiene rubber constituting the pedal plate 3. 3) Polypropylene constituting the members other than the friction plate 6 and the pedal plate 3, the housing 4, the pedal shaft 2, the pedal arm 1, the fixed plate 5, and the like. 4) A polyurethane adhesive that bonds the pedal arm 1 to the pedal plate 3 and the like. 5) Silicon for covering and insulating electrical components such as the position sensor 8, the electrical circuit 10, and the connector 9. By adding an antistatic function to the basic resin material excluding silicon, the effect of reducing charge accumulation was achieved.

  According to Non-Patent Document 1, various antistatic resins have been developed and put on the market in the industry in order to prevent troubles caused by static electricity. An antistatic resin with a conductive path formed by adding a conductive material such as carbon black or metal powder is widely used in the semiconductor industry, the electronics industry, etc., in order to prevent damage caused by the discharge caused by the accumulated charge. Has reached. In the antistatic resin, as a result of the lowering of the surface specific electric resistance value, even if static electricity is generated due to friction, contact, or the like, it quickly leaks, so that it is difficult to accumulate charges inside. Therefore, by replacing the antistatic resin with an existing resin and adopting the accelerator pedal device, it is possible to reduce the occurrence of various troubles caused by static electricity.

  In Non-Patent Document 1, the purpose of the antistatic resin is described for each surface specific electrical resistance value. A normal resin has a surface specific electrical resistance value of 10 13 Ω or more, and is used for insulation purposes because static charges accumulate. Resins between 10 12 Ω and 10 13 Ω are charged but are used to prevent failures in the static state. Resin between 10 10 Ω and 10 12 Ω is charged but immediately decays and is used for the purpose of preventing failure in a dynamic state. Resin between 10 8 Ω and 10 9 Ω is not charged and is used for the purpose of preventing electricity storage. Resins between 10 7 Ω and 10 8 Ω are not charged and are used for the purpose of imparting conductivity. In the present invention, in accordance with this description, a resin having a surface specific electrical resistance value of 10 12 Ω or less and functioning for the purpose of antistatic is defined as an antistatic resin.

  There are methods to reduce the surface specific electrical resistance of the resin, such as attaching a metal coating to the surface by plating, or attaching a surfactant to the surface. The charge is accumulated without leaking, so the effect is insufficient. Therefore, in order to effectively reduce charge accumulation, it is necessary to mix a conductive substance into the resin and knead to form an effective conductive path inside. It is also advantageous in terms of sustainability of the effect. Examples of the conductive substance mixed in the resin include carbon fiber, conductive carbon black, carbon fibril, carbon nanotube, metal fiber, metal powder, metal flake, metal oxide powder, and metal-coated fiber. When the conductive material is mixed, care must be taken not to reduce the strength and durability, which are the structural requirements of the conventional accelerator pedal device.

  Antistatic resins should be provided for all resin parts. This is because the conductive path is formed over a wide range across the metal portion and the resin portion of the accelerator pedal device, and the effect of leaking charge is enhanced. Even if only one portion is provided, if the other is an insulating resin, there is a possibility that electric charge flows in and accumulates there and flows into the position sensor. Even if the insulating resin is separated from the position sensor, electric charges may flow into the position sensor through adjacent members. Therefore, even if an antistatic resin is provided only in a part, a sufficient effect cannot be expected. Also in the present invention, there is a possibility that charges flow into and accumulate in the insulating resin parts of the electrical circuit 10, and it is impossible to completely prevent a failure due to the accumulation of charges. However, by providing an antistatic resin except for the insulating parts, it is possible to form a conductive path in a wide range in the entire accelerator pedal device, and to quickly leak the generated charge, thereby making it difficult to cause a failure. .

  In view of the above circumstances, the present inventors have developed an electronic accelerator pedal device to which an antistatic function shown in Examples 1 and 2 is added. Each content will be described below.

  In order to impart an antistatic function to the resin material of Example 1, carbon black was kneaded as a conductive material. When carbon black is mixed, there is an inconvenience that it is limited to black, but it has already been used in many resin fuel tanks for automobiles for the purpose of preventing charging. Carbon black has good kneadability and dispersibility in the resin and is economical, and has effects such as a reinforcing effect on rubber, an improvement in mechanical strength of the resin material, and an ultraviolet deterioration prevention.

  Starting with tires, carbon black is generally blended with rubber, and there are precedents provided in the pedal plate of an accelerator pedal device. In that case, the purpose is to improve strength and wear resistance, and antistatic is not intended. Therefore, even if the surface specific electric resistance value of the rubber provided on the pedal plate is 10 12 Ω or less as a result of accident, the rubber is not included in the antistatic resin in the present invention. As the antistatic resin, a resin in which an effective conductive path is formed should be adopted.

  In order to form an effective conductive path for the entire accelerator pedal device, when setting the surface specific electrical resistance value, friction plate 6, pedal plate 3, fixed plate 5, etc. have a high degree of friction and generate and accumulate a lot of electric charge. The basic resin material constituting the parts to be made was set to a particularly low value. For other basic resin materials, the antistatic function was set to be effective. 1) Nylon has a surface intrinsic electrical resistance value of 10 4 Ω and a conductivity imparting level. 2) The styrene-butadiene rubber had a surface specific electrical resistance value of 10 8 Ω and a power storage prevention level. 3) Polypropylene had a surface electrical resistance value of 10 8 Ω and a power storage prevention level. 4) The polyurethane-based adhesive had a surface specific electrical resistance value of 10 to the 10th power, and a failure prevention level in a dynamic state. 5) Carbon black is not mixed in the silicon of the electric circuit insulating part.

  Nylon has a property of absorbing moisture, and the surface specific electrical resistance value tends to decrease as the water absorption increases. For this reason, in the case of nylon that has not been subjected to antistatic treatment, the surface specific electrical resistance value becomes higher in the region where the humidity is lower and the humidity is lower. For example, high-humidity countries such as Japan have lower surface specific electrical resistance values on average than low-humidity countries such as the United States, China, and Russia. By mixing carbon black as a conductive substance into nylon, it has become possible to stably leak electric charges without being influenced by such external environmental factors.

  When carbon black is mixed in, the appearance is limited to black, which may cause an undesirable case in terms of design. For this reason, in Example 2, zinc oxide was mixed as a conductive material into polypropylene, which is a basic resin material, instead of carbon black. Zinc oxide is excellent in economic efficiency and has an effect of improving strength and wear resistance by being mixed without losing the color of polypropylene near white. Each surface specific electrical resistance value of the resin material was set to the same value as in Example 1.

  In Examples 1 and 2, by providing an antistatic resin, an electronic accelerator pedal device having a conductive path formed over a wide range was realized. Therefore, even if there is electrification due to friction of the friction member, friction between the driver's shoes and the accelerator pedal, etc., or electrification due to static electricity generated in the vehicle, the charge leaks quickly and is difficult to accumulate, Various disturbances due to charge accumulation in the accelerator pedal device have been reduced.

  In an electronic accelerator pedal device provided with resin parts, it is possible to reduce the occurrence of troubles related to safe driving of a vehicle due to accumulation of electric charges. The present invention can be applied to all vehicles that use an electronic accelerator pedal to control the driving force.

1 Pedal Arm 2 Pedal Shaft 3 Pedal Plate 4 Housing 5 Fixed Plate 6 Friction Plate 7 Spring 8 Position Sensor 9 Electric Circuit 10 Connector

Claims (2)

  An electronic accelerator pedal that is applied to an electronic control system that detects the depression operation of the accelerator pedal by a sensor and converts it into an electrical signal, and controls the driving force of the vehicle based on the electrical signal, comprising an antistatic resin. A characteristic accelerator pedal device.   An electronic accelerator pedal that is applied to an electronic control system that detects the depression operation of the accelerator pedal by a sensor and converts it into an electrical signal, and controls the driving force of the vehicle based on the electrical signal, is provided with an antistatic resin. A characteristic accelerator pedal device.

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