JP2015113753A - Motor-driven throttle valve control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor-driven throttle valve control device having a structure capable of reducing abrasion of a full-open stopper portion, without increasing friction around a throttle shaft.SOLUTION: A motor-driven throttle valve control device has a structure that, in mechanically fully opening a throttle valve, a full-open stopper 13A of a throttle gear 13 and a full-open stopper 6ZA of a throttle body 6 are kept into contact with each other, and normal lines of the contact faces 13M, 6M obviously do not have an orthogonal relationship. Thus, an axial 3Z component FZ of a biasing force F of a return spring 16 acts on a throttle shaft 3 in the throttle gear 13, in mechanical full-opening of the throttle valve, the throttle shaft 3 is biased in an axial direction 3Z, and swing of the shaft by input of vibration can be suppressed. As a result, abrasion in a full-open stopper portion can be reduced.

Description

The present invention relates to a motor-driven throttle valve controller for an internal combustion engine, and more particularly to a motor-driven throttle valve controller for a diesel engine.

  As a motor-driven throttle valve control device for an internal combustion engine, one described in Patent Document 1 is known. In an operation mode in which control of the intake air flow rate of the internal combustion engine at the throttle valve or negative suction pressure is not required, the motor drive power is cut off and the throttle valve is biased to the fully open side by the spring force, and the intake passage A stopper provided in a housing (hereinafter referred to as a throttle body) provided with a gear fixed to the shaft comes into contact with each other and the fully open position is restricted. In this prior art, the bearing that rotatably holds the shaft is a needle bearing, and a C-type washer (hereinafter referred to as a thrust retainer) is inserted into a slit provided in the shaft, and the thrust retainer is sandwiched between the needle bearing and the throttle body. By fixing, the shaft is regulated in the axial direction. The side surface of the slit part of this shaft and the side surface of the thrust retainer slide to generate friction, but it does not increase the sliding resistance, and considering the ease of assembly of the thrust retainer to the slit part, Since the width is set larger than the plate thickness of the C-type washer, the shaft is restricted in the axial direction, but there is a minute backlash.

  For this reason, the shaft shaft direction vibration input exceeds the frictional force of the stopper and the gear generated by the spring biasing force when the motor drive power is cut off and the gear is in contact with the stopper of the throttle body and fully opened. When the is applied, the shaft vibrates due to the presence of play, and the contact portion between the stopper and the gear is rubbed and worn. Due to the vibration of the shaft due to the presence of this play, not only the contact portion of the fully open stopper portion wears but also the contact portion of the thrust retainer and the slit portion of the shaft, the needle roller, when the bearing is the above-mentioned structure of the needle bearing. And the contact part of the shaft may be fretting worn. In particular, at the mechanical full open point where the throttle valve opening is fixed, the contact portion is fixed, and therefore local wear occurs. In addition, the wear generated by the wear is fixed and tends to stay at the contact portion, and the generated wear powder may accelerate the wear. The acceleration of wear means a decrease in the life of the throttle valve control device, but other effects may be as follows.

  In the case of a throttle valve control system based on the mechanical throttle valve full open point, the reference opening changes due to wear of the fully open stopper contact portion, so that the throttle valve position accuracy deteriorates depending on the details of the control system.

  Due to increased sliding resistance due to wear of the thrust retainer and the slit part of the shaft, and the contact part between the needle roller and the shaft, the power of the motor required for operation increases, the power consumption increases, and the power consumption increases, The motor is likely to generate heat. If the heat generation of the motor is extremely large, the motor life may be reduced.

In the case of a control logic with low robustness, controllability deteriorates due to increased friction due to wear.
Etc. are considered.

  As a method of suppressing the vibration of the shaft, there is a method of applying an axial pressure to the shaft by using a compression reaction force of a spring that urges the throttle valve to the fully open side. And the inner wall surface of the intake passage of the throttle body are in sliding contact with each other, the frictional resistance of the contact sliding portion is increased by the axial pressure of the spring, and wear of the throttle valve and the intake passage wall is rebounded. As described above, an increase in sliding resistance increases power consumption or deteriorates the control accuracy of the throttle valve. When the throttle valve and the intake passage wall are worn, the intake air passage area of the throttle valve changes, leading to deterioration in controllability of the air flow rate and negative pressure.

  Regarding the contact between the throttle valve and the inner wall of the intake passage of the throttle body described above, if the clearance between the throttle valve and the intake passage wall is set larger than the backlash between the thrust retainer and the slit portion of the shaft, the sliding between the throttle valve and the intake passage wall will be described. Although the movement can be avoided, there is a possibility that the throttle valve fully closed leakage amount increases and the required flow rate characteristic of the throttle valve cannot be obtained. Further, as described above, there is a rebound in which the side surface of the thrust retainer and the side surface of the slit portion slide, and the frictional resistance of the contact sliding portion increases due to the axial pressure of the spring.

  The problem due to the axial play of the shaft described above may occur when the radial clearance is set even when the shaft bearing is not only a needle bearing but also a ball bearing. When the bearing is a ball bearing, the outer ring of the ball bearing is fixed to the throttle body, the shaft is fixed to the inner ring of the ball bearing, and the shaft axial direction is regulated. In the case of ball bearings, the effect of sliding resistance due to the pressure in the shaft axial direction is small, so it is common to apply pressure in the shaft axial direction using the compression reaction force of the spring that biases the throttle valve to the fully open side. However, since it is a torsion spring that urges in the shaft rotation direction, the reaction force obtained by compressing in the shaft axis direction is smaller than the urging force in the rotation direction. In a large environment, the shaft may not be able to suppress axial deflection.

  In particular, in the case of a throttle valve control device for an internal combustion engine with a large displacement, a throttle valve corresponding to a large-diameter intake passage and an intake passage is set, and the mass of the throttle valve and the shaft is also increased. In comparison, the shaft is likely to swing with respect to the same vibration input acceleration.

  As described above, in an environment where the vibration load is large, it is difficult to suppress wear of the fully-open stopper and to secure low friction around the throttle shaft.

JP2012-247323A

  An object of the present invention is to provide a motor-driven throttle valve control device having a structure that can reduce wear of a fully-open stopper without increasing friction around the throttle shaft.

  In order to achieve the object of the present invention, when the motor drive power is cut off, the normal vector of the contact surface where the gear urged by the spring in the fully open direction and the stopper provided in the throttle body abuts. And the throttle rotation shaft is clearly not in a direct relationship.

  According to the present invention, when the gear is pressed against the stopper by the biasing force of the spring, the spring biasing force vector and the normal vector of the contact surface of the gear and the stopper are not parallel. A component force is generated in the direction of the contact surface between the gear and the stopper and in the direction of the throttle rotation axis, and a force urging in the direction of the shaft rotation axis acts on the shaft. The biasing force in the shaft rotation direction can be obtained by controlling the normal direction of the contact surface between the gear and the stopper so that the shaft does not rattle due to vibration input. In other words, even if the vibration input is applied, the shakiness of the shaft can be suppressed. The urging force in the direction of the shaft rotation axis is generated when the gear comes into contact with the stopper. When the motor is driven and the gear is separated from the stopper, the urging force becomes zero. Since the urging force does not act when the throttle valve is controlled by the motor, the friction of the throttle shaft due to the throttle shaft direction force does not increase. According to the present invention, it is possible to provide a motor-driven throttle valve control device having a structure capable of reducing the wear of the fully open stopper without increasing the friction around the throttle shaft.

The expanded sectional view of the throttle valve device in the example of the present invention 1 is an enlarged sectional view of the bearing portion of FIG. The figure explaining the effect of this invention using FIG. Sectional view of motor-driven throttle valve device used in diesel engine vehicles Plan view of gear storage chamber of motor-driven throttle valve device used in diesel engine vehicles External view of motor-driven throttle valve device used in diesel engine vehicles Arrow view with the gear cover removed of a motor-driven throttle valve device used in diesel engine vehicles

  The motor-driven throttle valve device according to the embodiment of the present invention includes a gear that is urged by a spring in the full-open direction of the throttle valve when the motor drive power is cut off, and a stopper provided on the throttle body. The normal vector of the contact surface that hits and the throttle rotation axis is not clearly perpendicular.

  A first embodiment in which the present invention is applied to a motor-driven throttle valve device will be described with reference to FIGS.

  FIG. 1 is an enlarged sectional view of a throttle valve device in an embodiment of the present invention.

  A needle bearing 9 that is a bearing of the throttle shaft 3 is press-fitted and fixed to a bearing boss portion 7 of a throttle body 6 that is a casing. A thrust retainer 12, which is a C-type washer, is inserted into the slit 3A of the throttle shaft 3, and the side surface 12A of the thrust retainer 12 is sandwiched between the shell 9A of the needle bearing 9 and the lower side surface 7A of the bearing boss portion 7. It is fixed. A throttle gear 13 including a metal plate 14 and a resin molding portion 15 is fixed to the throttle shaft 3 with a nut 17. The throttle gear 13 is provided with a fully open stopper 13A for restricting rotation on the throttle valve fully open side. The throttle body is provided with a fully-open stopper 6A configured integrally, and when the throttle shaft 3 rotates in the throttle valve fully-open direction, the fully-open stopper 13A of the throttle gear 13 and the fully-open stopper 6A of the throttle body 6 abut. Thus, the opening on the throttle valve fully open side is mechanically regulated. A turn spring 16 is disposed on the outer peripheral portion of the bearing boss 7 to urge the throttle gear 13 in the rotation direction of the throttle valve fully opened. The enlarged sectional view of FIG. 1 shows a state where the fully open stopper 13A of the throttle gear 13 and the fully open stopper 6A of the throttle body 6 are in contact.

  FIG. 2 is an enlarged cross-sectional view of the bearing portion of FIG.

  The groove width of the slit portion 3 </ b> A of the throttle shaft 3 is set wider than the thickness of the thrust retainer 12. Therefore, a gap 3C exists between the side surface 3B of the slit portion 3A of the throttle shaft 3 and the side surface 12A of the thrust retainer 12, and the throttle shaft has a slight backlash in the shaft rotation axis direction.

  For this reason, when a large vibration input acts on the throttle valve control device in the direction of the rotation axis of the throttle shaft 3, the throttle shaft vibrates due to the play.

  FIG. 3 is a diagram showing the effect of the present invention using FIG.

  Reference numeral 3Z denotes a rotation shaft of the throttle shaft 3.

  Reference numeral F is an urging force that presses the stopper 13A of the throttle gear 13 against the stopper 6B of the throttle body by the return spring 16, and is an urging force in a direction perpendicular to the rotary shaft 3Z.

  The side surface 3M of the fully open stopper 13A of the throttle gear 13 and the side surface 6M of the fully open stopper 6A of the throttle body 6 are in contact with each other in the throttle valve mechanically fully open state, and the side surface 3M and the side surface 6M are in contact with the rotation shaft 3Z of the throttle shaft 3. Is inclined at an angle θ. Therefore, the urging force F is decomposed into a component FN in the normal direction of the side surface 6M of the stopper 6A and a component FZ in the direction of the rotation shaft 3Z, and the force FZ in the direction of the rotation shaft 3Z is applied to the throttle gear 13 by the urging force F. Works.

Note that the decomposition components FN and FZ of the urging force F can be expressed by the following equations.
FN = F / cos θ
FZ = F × tanθ

  In the throttle valve mechanically fully opened state, the force FZ of the urging force F component in the direction of the rotation axis 3Z acts on the throttle gear 13, so that rattling of the throttle shaft can be suppressed. In the throttle valve control state, since the fully open stopper 13A of the throttle gear 13 and the fully open stopper 6A of the throttle body 6 are not in contact with each other, the force of the FZ component does not act, so there is no influence on controllability.

  Next, an example in which the stopper structure is applied to a motor-driven throttle valve controller for a diesel engine will be specifically described with reference to FIGS.

  FIG. 4 is a main cross-sectional view, and FIGS. 5 to 7 are diagrams for explaining the detailed structure.

  The configuration of the motor-driven throttle valve control device will be described below.

  An intake passage 1 (hereinafter referred to as “bore”) and a motor housing 20A for housing the motor 20 are molded together in a throttle body 6 which is an aluminum die-cast throttle valve assembly.

  A metal rotating shaft (hereinafter referred to as a throttle shaft) 3 is disposed on the throttle body 6 along one diameter line of the bore 1. Both ends of the throttle shaft 3 are rotatably supported by needle bearings 9 and 10. The needle bearings 9 and 10 are press-fitted and fixed to bearing boss portions 7 and 8 provided on the throttle body 6. Further, after inserting a C-type washer (hereinafter referred to as a thrust retainer) 12 into a slit portion provided on the throttle shaft 3, a needle bearing 9 is press-fitted, thereby restricting the axial movable amount of the throttle shaft 3. .

  Thus, the throttle shaft 3 is rotatably supported with respect to the throttle body 6. On the throttle shaft 3, a throttle valve (hereinafter referred to as a throttle valve) 2 made of a metal disk is inserted into a slit provided on the throttle shaft 3 and fixed to the throttle shaft 3 with screws 4 and 5. .

  Thus, when the throttle shaft 3 rotates, the throttle valve 2 rotates, and as a result, the cross-sectional area of the intake passage changes and the intake air flow rate to the engine is controlled.

  The motor housing 20A is formed substantially parallel to the throttle shaft 3, and the motor 20 composed of a brush type DC motor is inserted into the motor housing 20A, and the flange of the bracket 20B of the motor 20 is inserted into the side wall 6A of the throttle body 6. The part is fixed by screwing with a screw 21. A wave washer 25 is disposed at the end of the motor 20 to hold the motor 20.

  The openings of the bearing boss portions 7 and 8 are sealed with needle bearings 9 and 10 to constitute a shaft seal portion so as to keep secret. Further, the end on the bearing boss 8 side is sealed with a cap 11 to prevent the end of the throttle shaft 3 and the needle bearing 10 from being exposed.

  As a result, air leakage from the bearing portion or grease for lubricating the bearing is prevented from leaking into the outside air or into a sensor chamber to be described later.

  A metal output gear 22 having the smallest number of teeth is fixed to the rotating shaft end of the motor 20. A reduction gear mechanism and a spring mechanism for rotationally driving the throttle shaft 3 are collectively arranged on the side surface of the throttle body on which the output gear 22 is provided. These mechanisms are covered with a resin cover (hereinafter referred to as a gear cover) 26 fixed to the side surface of the throttle body 6. The so-called gear housing chamber covered with the gear cover 26 is provided with an inductance-type non-contact type rotational angle detection device (hereinafter referred to as a throttle sensor), and the rotational angle of the throttle shaft 3, and consequently the throttle valve. An opening of 2 is detected.

  A throttle gear 13 is fixed to the end of the throttle shaft 3 on the gear cover 26 side. The throttle gear 13 includes a metal plate 14 and a resin gear portion 15 formed by resin molding on the metal plate 14. A cup-shaped recess is provided at the center of the metal plate 14, and a gear-forming flange is provided at the open end of the recess. A resin material gear portion 15 is molded on the flange portion by resin molding.

  The metal plate 14 has a hole in the center of the recess. A screw groove is formed around the tip of the throttle shaft 3. The metal plate 14 is fixed to the throttle shaft 3 by inserting the tip of the throttle shaft 3 into the hole of the concave portion of the metal plate 14 and screwing the nut 17 into the screw portion. Thus, the metal plate 14 and the resin gear portion 15 molded there rotate integrally with the throttle shaft 3.

  A return spring 16 formed of a string-wound spring is sandwiched between the back surface of the throttle gear 13 and the side surface of the throttle body 6.

  One side of the return spring 16 surrounds the periphery of the bearing boss portion 7, and its tip is engaged with a notch formed in the throttle body 6, so that the end portion cannot rotate in the rotational direction. The other end surrounds the cup-shaped portion of the metal plate 14, and its tip is locked in a hole formed in the metal plate 14, so that this end portion cannot rotate in the rotation direction.

  Since the present embodiment relates to a diesel throttle valve control device, the initial position of the throttle valve 2, that is, when the motor 20 is powered off, the throttle valve 2 is set as the initial position, and the given opening position is the fully open position. It is.

  For this reason, the return spring 16 is preloaded in the rotational direction so that the throttle valve 2 maintains the fully open position when the motor 20 is not energized.

  Between the output gear 22 attached to the rotating shaft of the motor 20 and the throttle gear 13 fixed to the throttle shaft 3, it is rotatably supported by a metal gear shaft 24 press-fitted and fixed to the side surface of the throttle body 6. The intermediate gear 23 is engaged. The intermediate gear 23 includes a large-diameter gear 23A that meshes with the output gear 22 and a small-diameter gear 23B that meshes with the throttle gear 13. Both gears are integrally molded by resin molding. These gears 22, 23A, 23B, and 15 constitute a two-stage reduction gear mechanism.

  Thus, the rotation of the motor 20 is transmitted to the throttle shaft 3 through this reduction gear mechanism.

  These speed reduction mechanism and spring mechanism are covered with a gear cover 26 made of a resin material. A groove into which the seal member 30 is inserted is formed on the periphery of the opening end side of the gear cover 26. When the gear cover 26 is put on the throttle body 6 with the seal member 30 mounted in the groove, the seal member 30 is inserted. Is in close contact with the end face of the frame around the gear storage chamber formed on the side surface of the throttle body 6 to shield the gear storage chamber from the outside air. In this state, the gear cover 26 is fixed to the throttle body 6 with six clips 27.

DESCRIPTION OF SYMBOLS 1 Bore 2 Throttle valve 3 Throttle shaft 4, 5, 21 Screw 6 Throttle body 7, 8 Bearing boss part 9, 10 Needle bearing 11 Cap 12 Thrust retainer 13 Throttle gear 14 Metal plate 15 Resin material gear part 16 Return spring 17 Nut 18 Rotor 20 Motor 22 Output gear 23 Intermediate gear 24 Gear shaft 25 Wave washer 26 Gear cover 27 Clip 28 Throttle sensor sensor

Claims (1)

A housing that constitutes an intake passage, a throttle valve, a shaft that holds the throttle valve and rotates on an axis orthogonal to the intake passage, a bearing that rotatably supports the shaft and is fixed to the housing, and A motor provided with a motor for rotationally driving the throttle valve, a gear fixed to the shaft on the rotary shaft and transmitting the rotation of the motor to the shaft, and a spring for biasing the throttle valve in the fully open direction In the drive type throttle valve control device,
The housing includes a stopper that restricts the rotation of the gear, and when the motor drive power is cut off, the gear is pressed against the stopper of the housing by the urging force of the spring, but is pressed against and contacted. 2. A motor-driven throttle valve control device according to claim 1, wherein a normal vector of a contact surface between the gear and the stopper of the casing is not perpendicular to the rotation axis of the shaft.