JP2007321739A - Driving device of valve lift control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving device of an internal combustion engine for preventing vibration of an engine being transmitted to the driving device and a motor tip end vibrating and breaking. <P>SOLUTION: A housing 21 of the driving device is formed into a shape of a housing for supporting a motor output shaft 37 of the driving device and the motor tip end 39 on the opposite side of the motor output shaft 37. Thereby, vibration of the engine being transmitted to the driving device is reduced. By installing a seal member 35 on the motor output shaft 37, the seal member 35 functions as a seal member for preventing a lubricant from flowing to an electric motor 30. Even in the case where a gear is in an abnormally locked state, the seal member 35 also functions as an elastic member capable of absorbing shock. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drive device for a valve lift control device that converts rotation of a motor into a reciprocating linear motion of a control shaft and adjusts a control amount of a controlled body according to an axial position of the control shaft.

  There is known a drive device that adjusts the lift amount of a valve by providing an intermediate drive mechanism between a camshaft and an intake or exhaust valve (see Patent Document 1). In the apparatus of Patent Document 1, the mediation drive mechanism is composed of a control shaft, a swing cam provided on the control shaft, and an actuator that drives the control shaft to an axial position. The relative lift difference between the intake or exhaust cam and the swing cam is adjusted by driving the control shaft in the axial direction, and as a result, the lift amount of the valve is controlled. Here, the actuator drives the control shaft in the axial direction by hydraulic pressure.

In recent years, as a method for adjusting the axial position of the control shaft, an electric drive device using a motor for the drive unit instead of using the hydraulic pressure of the pressure chamber set on one end side of the control shaft has been considered (patent) Reference 2). In such an electric drive device, the position of the control shaft in the axial direction is adjusted by converting the drive torque output from the motor into the axial direction of the control shaft using a rotating cam or the like.
JP 2001-263015 A JP 2006-29209 A

  In such an electric drive device, the reliability of the motor that outputs the power necessary to drive the control shaft in the axial direction is important. By the way, the electric drive unit is connected to the engine. Therefore, the vibration of the engine is transmitted to the motor, and the motor may be damaged due to the vibration. Therefore, ensuring the reliability of the motor is a big issue.

  In Patent Document 1, the motor of the drive device is supported in a cantilever state on the output side, and the motor body on the side opposite to the supported side may be shaken by the vibration of the engine, so that the motor may break down. is there. In particular, when a motor having a long overall length is used for the driving device, the motor body tends to swing greatly due to engine vibration, and the motor is likely to break down.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an internal combustion engine drive device that prevents the vibration of the engine from being transmitted to the electric drive device and the motor body from vibrating and failing.

  Accordingly, in the invention according to claim 1, in the drive device of the valve lift control device that controls the valve lift amount of at least one of the intake valve and the exhaust valve of the internal combustion engine by changing the axial position of the control shaft, A power output device that outputs power necessary to change the axial position of the shaft, a drive unit that transmits power output from the power output device to the control shaft, and a housing that houses the power output device; The power output device includes a motor including a motor main body and a power output unit, and the housing fixes the motor main body on the opposite side to the output side of the power output device provided with the drive unit.

  When the vehicle is mounted, the engine and the drive device of the valve lift control device are connected. For this reason, when the output side of the drive output device is supported in a cantilevered state, the motor body on the opposite side supported by the vibration of the engine may vibrate greatly and the motor may break down. On the other hand, in the invention according to claim 1, since the motor body is fixed on the opposite side to the output side of the power output device provided with the drive unit, the motor body is not shaken by the vibration of the engine. Can be reduced.

  Further, as in the invention according to claim 2, the power output device may be provided with a seal member that prevents the lubricant that lubricates the drive unit from flowing into the power output device. A lubricant is used in the drive unit of the drive device of the valve lift control device. Since this lubricant may break down when it flows into the power output device, the invention according to claim 2 can prevent the lubricant from flowing into the power output device.

  Further, as in the invention according to claim 3, the seal member may be attached to the output side of the power output apparatus.

  Further, as in the invention according to claim 4, a groove portion into which the seal member is fitted is provided on the inner periphery of the housing, the seal member is fitted into the groove portion, and the power output device is supported by the housing. May be. That is, since the seal member is attached to the output side of the power output device, the power output device is supported by the housing by fitting the seal member into the groove on the inner periphery of the housing. As a result, not only the motor body is fixed to the housing, but also the output side of the power output device is supported by the housing, so it is possible to further reduce motor vibration and fretting due to minute vibration with the housing. Can also be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 shows a valve lift control device according to an embodiment of the present invention, and FIG. 3 shows a mechanism for controlling the valve lift amount. The valve lift control device 10 is provided in a vehicle engine and controls the valve lift amount of the intake valve 11 of the engine. The valve lift control device 10 includes a change mechanism 12 and a drive device 20.

  The changing mechanism 12 has a helical spline fitting of the input portion 15 and the swing cam 16 to a slider gear 14 that can move linearly in the axial direction of the control shaft 13 together with the control shaft 13, and according to the axial position of the control shaft 13. Thus, the relative phase difference between the input unit 15 and the swing cam 16 changes. The input unit 15 is in contact with the intake cam 18 of the cam shaft 17, and the swing cam 16 is provided so as to be able to contact the rocker arm 19 of the intake valve 11. The relative phase difference between the input unit 15 and the swing cam 16 is provided. Accordingly, the rocking angle of the rocker arm 19 changes. Therefore, in the change mechanism 12, the valve lift amount of the intake valve 11 changes as the axial position of the control shaft 13 changes. In this embodiment, the valve reaction force transmitted from the intake valve 11 to the control shaft 13 acts on the control shaft 13 as an axial force toward the drive device 20 side.

  The drive device 20 linearly drives the control shaft 13 of the change mechanism 12 in the axial direction. As shown in FIGS. 4 and 5, the drive device 20 includes a housing 21, an electric motor 30, a linearly driven follower 40, a rotating cam 50, an angle sensor 60, and a control unit 70.

  The housing 21 as a fixed node is fixed in position so as not to move relative to the engine. In the housing 21, a guide hole 23 into which the guide shaft 43 of the linear follower 40 is inserted is formed coaxially with the control shaft 13.

  The electric motor 30 is a DC brush motor, and houses a motor shaft 32 as a power output unit and a coil (not shown) on the inner peripheral side of a motor cover 31 as a motor main body fixed to the housing 21 so as not to be relatively movable. . A motor gear 33 is attached to the motor shaft 32. A control unit 70 is connected to the coil, and a drive torque is generated in the motor shaft 32 by energization of the coil by the control unit 70, and the motor shaft 32 rotates forward and backward together with the motor gear 33.

  The linearly driven follower 40 has an output shaft 41 and a roller 46 as a contact. The output shaft 41 is formed in a bottomed cylindrical shape corresponding to the guide hole 23. The bottom end 42 of the output shaft 41 is coaxially linked to the end of the control shaft 13 opposite to the end where the slider gear 14 is provided. The guide shaft 43 is fitted in the guide hole 23 of the housing 21 and can slide relative to the guide hole 23 in the axial direction. An anti-rotation member 45 mounted on the housing 21 is fitted in a groove 44 that opens on the outer peripheral wall surface of the output shaft 41 and extends in the axial direction so as to be slidable in the axial direction. Thereby, the output shaft 41 is prevented from rotating in the circumferential direction. The roller 46 is accommodated in the output shaft 41 and is supported by the output shaft 41 so as to be able to rotate forward and backward. The rotation shaft 47 of the roller 46 supported by the output shaft 41 is perpendicular to the axis of the control shaft 13. The roller 46 protrudes slightly from the opening end 48 of the output shaft 41.

  The rotation cam 50 is a plate cam and is supported by the housing 21 so as to be able to rotate forward and backward. The cam shaft 51 of the rotary cam 50 that is supported by the housing 21 via the bearing 26 is perpendicular to the axis of the control shaft 13. A cam drive gear 52 and a sensor drive gear 53 are mounted on both ends of the cam shaft 51, respectively. An intermediate gear 54 that meshes with the cam drive gear 52 meshes with the motor gear 33, thereby constituting a speed reduction mechanism 55 that increases the drive torque generated by the electric motor 30 and transmits it to the rotary cam 50. The rotation angle range of the cam drive gear 52 is limited by the stopper member 56 mounted on the cam drive gear 52 being locked to a locking portion (not shown) of the housing 21.

  A cam surface 57, which is an outer peripheral surface of the rotating cam 50, is in contact with a protruding portion 49 that protrudes from the opening side end portion 48 of the output shaft 41 in the roller 46. Thus, the rotating cam 50 is located on the opposite side of the roller 46 from the control shaft 13 in the axial direction of the control shaft 13. When the rotary cam 50 rotates, the linearly driven follower 40 linearly moves in the axial direction of the control shaft 13 in accordance with the cam lift amount at the contact point P where the roller 46 contacts with the cam surface 57. The control shaft 13 linked to the shaft 41 also moves linearly in the axial direction.

  As shown in FIGS. 4 and 6, the angle sensor 60 includes a sensor gear 61, a magnet holder 62, a magnet 63, and a magnetic detection element 64. The sensor gear 61 meshes with the sensor drive gear 53 to constitute a synchronous rotating body that rotates in synchronization with the rotary cam 50. The magnet holder 62 is formed in a cylindrical shape, and is attached to the sensor gear 61 coaxially. Magnets 63 are mounted at two locations on the inner peripheral wall of the magnet holder 62 with the rotation center O therebetween. The two magnets 63 are arranged so that the magnetic poles formed on the opposing surface 65 side are opposite to each other. The magnetic detection element 64 is a Hall element and detects the rotation angle of the sensor gear 61 based on the amount of magnetic flux projected from the magnet 63. The magnetic detection element 64 is connected to the control unit 70, and transmits a detection signal representing the detected rotation angle as a voltage to the control unit 70.

  4 receives the detection signal of the magnetic detection element 64, and calculates the cam lift amount of the rotating cam 50 at the contact point P based on the rotation angle of the sensor gear 61 represented by the voltage of the detection signal. Further, the control unit 70 calculates the actual valve lift amount based on the axial position of the control shaft 13 corresponding to the calculated cam lift amount, and fills the difference between the actual valve lift amount and the target valve lift amount. Thus, the energization to the electric motor 30 is controlled. Here, the target valve lift amount is a physical amount determined based on the driving state of the vehicle such as the engine speed and the accelerator opening.

  In such a valve lift control device 10, when the electric motor 30 is energized and driven by the control unit 70, the driving torque generated by the electric motor 30 is transmitted to the rotary cam 50 through the speed reduction mechanism 55. When the rotary cam 50 is rotated by the transmitted driving torque, the linearly driven follower 40 moves linearly in the axial direction of the control shaft 13 together with the control shaft 13. At this time, since the change mechanism 12 changes the valve lift amount according to the axial position of the control shaft 13, the valve characteristics of the engine such as the operating angle and the maximum valve lift amount are adjusted.

  Next, the characteristic part of this embodiment is demonstrated.

  As in this embodiment, the housing 21 of the driving device is formed into a housing shape that supports the motor output shaft 37 of the driving device and the motor main body end 39 on the opposite side to the motor output shaft 37. Transmission of engine vibration to the drive device can be reduced. The seal member 35 installed on the motor output shaft 37 not only has a function of preventing the lubricant from flowing into the electric motor 30 but also absorbs shock when the motor gear 33 is locked due to an abnormality. It can also function as an elastic material.

  In the present embodiment, the housing 21 that covers the electric motor 30 has the shape shown in FIG. In FIG. 1, the housing 21 is formed so as to cover the electric motor 30. The motor main body end 39 opposite to the motor output shaft 37 is fixed by fixing the motor fixing surface 38 and the housing 21 with the motor fixing bolt 34. Thus, by making the shape of the housing 21 fixed to the motor output shaft 37 by the motor output shaft 37 and the motor main body end portion 39, the vibration of the motor main body end portion 39 due to engine vibration can be prevented.

  In the motor output shaft 37, an O-ring shaped seal member 35 is inserted into a groove provided in the inner diameter of the housing 21. The motor output shaft 37 of the electric motor 30 is fixed by inserting the motor output shaft 37 into the seal member 35. The seal member 35 can prevent the lubricant that lubricates the drive unit such as the motor gear 33 from flowing into the electric motor 30.

  When the electric motor of the drive device 20 is supported in a cantilevered state on the output shaft side, the motor main body end 39 on the opposite side of the electric motor output shaft 37 is shaken by the vibration of the engine, so that the motor breaks down. There was a fear. However, like the shape of the present embodiment, the motor output shaft 37 of the electric motor 30 is supported by the O-ring shaped seal member 35 and the shape of the housing 21 is fixed to the electric motor 30 by the motor tip 39. Thus, fretting due to minute vibration with the housing can be prevented. Further, since the motor output shaft 37 and the motor body end portion 39 of the electric motor 30 support the fulcrum for supporting the electric motor as compared with the case where the electric motor is supported in a cantilever state, the sealing member 35 not only prevents the lubricant from flowing into the electric motor 30, but also functions as an elastic material. Thereby, even when the motor gear 33 is suddenly locked, the impact force is absorbed by the seal member 35, so that the electric motor 30 and the gear portion can be prevented from being broken.

  Further, by fixing the motor output shaft 37 with the O-ring shaped seal member 35, the motor output shaft 37 can be driven by the seal member 35 even when the processing accuracy of the output portion is not strict when positioning the electric motor 30. Can be guided and supported. That is, the positioning of the motor output shaft 37 is facilitated.

  As described above, by adopting the shape as in the present embodiment, it is possible to prevent the motor main body end portion 39 from vibrating due to the vibration of the engine being transmitted to the driving device, and the motor from being damaged. As a result, the reliability of the motor of the drive device can be improved.

  In the present embodiment, the electric motor 30 is fixed as the housing shape for fixing the electric motor 30 by the front end of the motor and fixed by the motor fixing surface 38. However, the housing shape may be such that the electric motor 30 is inserted from the side surface and fixed. . Further, the present embodiment may be applied to an exhaust valve, and in that case, can be applied similarly to the present embodiment.

It is a housing shape which covers the drive output device of this embodiment. It is a valve lift control device of this embodiment. It is sectional drawing which shows the drive device of the valve lift control apparatus of this embodiment. It is a drive device of the valve lift control device of this embodiment. It is sectional drawing which shows the drive device of the valve lift control apparatus of this embodiment. It is a perspective view (A) and (B) which shows the principal part of the angle sensor of the valve lift control apparatus of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Valve lift control apparatus 13 Control shaft 21 Housing 30 Motor 35 Seal member 39 End part of motor main body

Claims (4)

In the drive device of the valve lift control device that controls the valve lift amount of at least one of the intake valve and the exhaust valve of the internal combustion engine by changing the axial position of the control shaft,
A power output device that outputs power necessary to change the axial position of the control shaft;
A drive unit that transmits power output from the power output device to the control shaft; and a housing in which the power output device is housed.
The power output device includes a motor including a motor main body and a power output unit,
The drive device for a valve lift control device, wherein the housing fixes the motor body on the opposite side to the output side of the power output device in which the drive unit is provided. 2. The drive device for a valve lift control device according to claim 1, further comprising a seal member that is provided in the power output device and prevents a lubricant that lubricates the drive unit from flowing into the power output device. The drive device for a valve lift control device according to claim 2, wherein the seal member is attached to an output side of the power output device. The housing includes a groove portion on the inner periphery in which the seal member is fitted,
4. The drive device for a valve lift control device according to claim 3, wherein the power output device is supported by the housing by fitting the seal member into the groove. 5.

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