JP4070124B2 - Decompression device for internal combustion engine - Google Patents

Description

  The present invention relates to a decompression device that opens an intake valve or an exhaust valve in a decompressed state by using a valve operating mechanism for opening and closing the intake valve or the exhaust valve when the internal combustion engine is started. is there.

  Generally, when the operation of the internal combustion engine is stopped with both the intake valve and the exhaust valve closed, the cylinder is almost completely closed. Requires rotational torque.

Therefore, conventionally, an intake valve or an exhaust valve that is opened and closed by a valve operating mechanism interlocked with a crankshaft is configured to be opened by a decompression device when the internal combustion engine is started (for example, Patent Documents). 1).
JP 2001-263018 A

  However, in this way, in addition to opening and closing the intake valve or the exhaust valve by the valve operating mechanism interlocked with the crankshaft, it is possible to configure the valve to open by the decompression device when starting the internal combustion engine. Since a decompression device is required in addition to the mechanism, there is a problem that the structure becomes complicated and not only increases in size but also increases in price and weight.

  According to the present invention, for example, in Japanese Patent Laid-Open No. 5-187212, in a recent internal combustion engine, the valve lift amount when the intake valve and / or the exhaust valve is opened and operated is determined according to the operating state of the internal combustion engine. Focusing on the proposal of a variable valve mechanism that can be changed so that it is small when the load is low or low, and large when the load is high or high, and this variable valve mechanism has a decompression function. Therefore, it is a technical problem to solve the above problem.

In order to achieve this technical problem, claim 1 of the present invention provides:
“A swing member is formed between the cam rotating in synchronization with the crankshaft and the intake valve or exhaust valve. The contact portion is disposed so as to swing by rotation of the cam with the contact portion as a fulcrum of rotation to open and operate the intake valve or exhaust valve, and the fulcrum member is in contact with the sliding surface of the fulcrum member. In the valve operating mechanism in the internal combustion engine configured to move along the sliding surface according to the operating state of the internal combustion engine,
The fulcrum member is configured such that a contact portion of the fulcrum member with respect to the sliding surface can move beyond the range of the entire operating range of the internal combustion engine on the sliding surface. the sliding surface, said contact portion is provided with ridges so that its contact portion rides when moving moves beyond the range of the entire operation range of the internal combustion engine, said contact portion of the the raised portion The swinging member is configured to rotate in a direction to open the intake valve or the exhaust valve when riding . "
It is characterized by that.

Further, claim 2 of the present invention provides
“In the description of claim 1, the fulcrum member moves in a direction away from the cam when the contact portion of the fulcrum member with respect to the sliding surface is in a low load or low rotation range in an internal combustion engine, Alternatively, it is configured to move in a direction approaching the cam when in a high rotation range, and further, the raised portion is provided in a portion of the sliding surface beyond the low load or low rotation range.
It is characterized by that.

  In the first aspect of the present invention, when the cam is rotated, the swinging member swings with the contact portion of the fulcrum member with respect to the sliding surface provided thereon as the fulcrum of the rotation center, so that the intake valve or the exhaust valve is Opens and closes.

  The fulcrum member moves along the sliding surface according to the operating state in the internal combustion engine, and by this movement, the swing angle in the swing member changes so as to increase or decrease. As a result, the valve lift when the intake valve or the exhaust valve is opened to operate can be changed according to the operating state of the internal combustion engine.

Then, by moving the fulcrum member so that the contact portion rides on the raised portion, the swing member moves the intake valve or exhaust valve by the amount that the contact portion of the fulcrum member rides on the raised portion. since rotates in a direction of opening the at this rotation, it is possible to open the intake valve or the exhaust valve to decompression state.

  That is, the fulcrum member for changing the valve lift according to the operating state of the internal combustion engine moves beyond the entire operating range of the internal combustion engine when the operation of the internal combustion engine is stopped. Or, since the exhaust valve is opened, the decompression state is established, so that the rotational torque at the start of the internal combustion engine can be reduced.

  As described above, the present invention can be opened and operated in the decompressed state using the variable valve mechanism as it is, and thus the structure is significantly simpler than the case where the decompressor is provided separately from the conventional valve mechanism. Thus, it is possible to reduce the size, reduce the weight, and reduce the price.

  Further, in the second aspect of the present invention, the fulcrum member moves in a direction in which the contact portion of the fulcrum member with respect to the sliding surface moves away from the cam when the load is low or the rotation speed is low. As the fulcrum length from this portion to the cam becomes longer, the swing angle in the swing member becomes smaller, and therefore the valve lift amount for opening the intake valve or the exhaust valve becomes smaller.

  Further, when the fulcrum member is in a high load or high rotation range, the contact portion with respect to the sliding surface of the fulcrum member moves in a direction away from the cam, and the fulcrum from the contact portion of the fulcrum member to the cam. When the length is shortened, the swing angle of the swing member is increased, so that the valve lift amount for opening the intake valve or the exhaust valve is increased.

  Thereby, the valve lift amount when the intake valve or the exhaust valve is opened and operated is set to be small at the low load or low rotation range and large at the high load or high rotation range depending on the operating state of the internal combustion engine. Can be changed.

  Then, by moving the fulcrum member so that the abutting portion rides over the raised portion beyond the low load or low rotation range, the swinging member is brought into contact with the raised portion at the abutting portion of the fulcrum member. Therefore, the intake valve or the exhaust valve can be opened to the decompressed state.

  When the fulcrum member moves so as to ride on the raised portion, the fulcrum length from the cam to the raised portion of the rocking member becomes longer, and as a result, the rocking angle of the rocking member to the decompressed state is On the contrary, since the raised portion is smaller than the case where the raised portion is located at a portion exceeding the high load or high rotation range, the intake valve or the exhaust valve is brought into a decompressed state by moving the fulcrum member to the portion that rides on the raised portion. It is possible to reliably reduce the operating force required to open the valve and reliably prevent the valve lift amount from being excessive when the intake valve or the exhaust valve is opened due to the rotation of the cam at the start.

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

  FIG. 1 shows a first embodiment.

  In FIG. 1, reference numeral 1 denotes a cylinder head in an internal combustion engine. The cylinder head 1 is provided with an intake port 2 into a cylinder (not shown), and an opening of the intake port 2 into the cylinder is provided at the opening. An intake valve 3 that is normally closed by a spring 4 is provided.

  A cam shaft 6 having a cam 5 that opens and closes the intake valve 3 is pivotally supported on the cylinder head 1 so as to rotate in conjunction with a crankshaft in the internal combustion engine.

  The upper end of the intake valve 3 is in contact with the distal end of a rocker arm 8 whose base end is pivotally attached to a bolt 7 screwed to the cylinder head 1 side.

  Reference numeral 9 denotes a swing member. The swing member 9 is disposed between the cam 5 and the rocker arm 8, and an upper end portion of the swing member 9 contacts the cam 5. A roller 10 is rotatably provided on a pin shaft 11, and the upper end of the roller 10 is slidably fitted into a guide groove 12 provided on the cylinder head 1, thereby allowing the roller 5 to slide relative to the cam 5. And is supported so as to reciprocate in the radial direction.

  On the other hand, on the cylinder head 1 side, a base end of a fulcrum member 13 is rotatably supported by a pin shaft 14, and a roller 15 provided rotatably at the distal end of the fulcrum member 13 is attached to the swing member. 9, a sliding surface 9 a provided on a side surface between the upper end portion and the lower end portion thereof is movably contacted in the longitudinal direction of the swing member 9, while the upper end portion of the swing member 9 is The roller 10 is pressed and urged against the cam 5 by a return spring 16 provided between the lower end portion of the swing member 9 and the cylinder head 1, so that the swing is caused by the rotation of the cam 5. The moving member 9 is configured to oscillate with a portion of the sliding surface 9a of the oscillating member 9 that contacts the roller 15 at the tip of the fulcrum member 13 as a fulcrum of the rotation center.

  By providing a cam surface 18 in contact with a roller 17 rotatably provided on the rocker arm 8 at the lower end portion of the rocking member 9, the rocking member 9 can be swung through the rocker arm 8 by rocking. The intake valve 3 is configured to open and act against the spring 4.

  The fulcrum member 13 is moved by an actuator 19 that operates according to the load in the internal combustion engine so that the roller 15 at the tip of the fulcrum member 13 moves from the middle load range shown by the solid line to the lower end side of the swing member 9. The roller 15 at the tip is moved and moved from the middle load range indicated by the solid line to the upper end side of the swing member 9 when the load is high.

  In this case, of the side surfaces of the oscillating member 9, the sliding surface 9a with which the roller 15 of the fulcrum member 14 contacts is formed as an arc surface with a radius R centering on the rotation center of the fulcrum member 13, In addition, the radius R of the arcuate sliding surface 9a is determined from a straight line 9b connecting the center of the pin shaft 11 at the upper end of the swinging member 9 and the center of the roller 17 in the rocker arm 8 to the rotation center of the fulcrum member 13. In the state where the fulcrum member 13 is moved to the upper end side of the oscillating member 9 and the state where the fulcrum member 13 is moved to the lower end side of the oscillating member 9. The moving member 9 is configured to be less displaced in the lateral direction.

  Note that the sliding surface 9a of the swing member 9 is a linear plane extending in parallel with the straight line 9b, instead of the arc surface as described above, while the fulcrum member 13 is the straight line. It may be so arranged that the rocking member 9 is less displaced and displaced in the lateral direction by moving in a direction parallel to 9b.

  In this configuration, the rocking member 9 has a center of rotation at a position where the roller 15 at the tip of the fulcrum member 13 contacts the sliding surface 9a due to the rotation of the cam 5 with which the roller 10 contacts the upper end. By swinging as a fulcrum, the intake valve 3 is pushed downward on the cam surface 18 at the lower end portion of the swinging member 9 via the rocker arm 8 against the spring and opens.

  When the load in the internal combustion engine increases to a high load region, the roller 15 at the tip of the fulcrum member 13 moves to the upper end side of the swing member 9 rather than in the middle load region indicated by the solid line, thereby swinging. The force point length from the force point F at which the roller 10 at the upper end of the member 9 contacts the cam 5 to the fulcrum S at which the roller 15 at the tip of the fulcrum member 13 contacts the swing member 9 is in the middle load range. While the force point length is reduced from X0 to X1, the action point length from the action point W where the cam surface 18 at the lower end of the rocking member 9 contacts the roller 17 in the rocker arm 8 to the fulcrum S is the medium load. The action point length Y0 in the region is increased from Y0 to Y1, and the swing angle of the swing member 9 is increased, and the opening operation of the intake valve 3 is performed at this large swing angle.

  When the load in the internal combustion engine falls to a low load range, the roller 15 at the tip of the fulcrum member 13 moves to the lower end side of the swinging member 9 from the middle load range shown by the solid line, so that the power point length is increased. Is longer from the force point length X0 to X2 in the middle load region, while the action point length is shortened from the action point length Y0 to Y2 in the middle load region, and the swing angle of the swing member 9 is increased. The opening operation of the intake valve 3 is performed at this small swing angle.

  That is, in the high load region, the swing angle of the swing member 9 is large, so that the maximum valve lift amount in the intake valve 3 is higher than the maximum valve lift amount in the medium load region.

  On the other hand, since the swing angle of the swing member 9 is small in the low load region, the maximum valve lift amount in the intake valve 3 is smaller than the maximum valve lift amount in the medium load region.

  Thereby, the valve lift amount when the intake valve 3 is opened and operated can be controlled to be large in the high load region and small in the low load region according to the load of the internal combustion engine.

  According to the present invention, in such a valve operating mechanism, the fulcrum member 13 contacting the sliding surface 9a of the swing member 9 is further moved to the lower end side beyond the low load region by the actuator 19 or manual operation. The raised portion 20 is provided on the sliding surface 9a of the swinging member 9 beyond the low load region, and the fulcrum member 13 is further moved beyond the low load region. When moving to the lower end side, the roller 15 in the fulcrum member 13 is configured to ride on the raised portion 20.

When the operation of the internal combustion engine is stopped, the oscillating member 13 is moved by moving the fulcrum member 13 over the low load region so as to ride on the raised portion 20 by the actuator 19 or manual operation. Since the member 9 rotates in the direction of opening the intake valve 3 by the amount of the roller 15 of the fulcrum member 13 riding on the raised portion 20, the intake valve 3 can be opened to the decompressed state by this rotation . it can.

  In this case, the raised portion 20 may be provided on a portion of the sliding surface 9a beyond the high load region, that is, a portion from the cam 5.

  On the other hand, as in the first embodiment described above, the raised portion 20 is provided in a portion of the sliding surface 9a beyond the low load region, that is, a portion from the cam surface 18. In this case, when the fulcrum member 13 is moved to a position where the roller 15 at the tip of the fulcrum member 13 rides on the raised portion 20, the fulcrum length X from the cam 5 to the raised portion 20 of the swinging member becomes longer, As a result, the swinging angle of the swinging member 9 to the decompressed state is smaller than that when the protruding portion 20 is positioned at a portion beyond the high load region, so that the fulcrum member 13 is moved to the protruding portion 20. The operation force required to open the intake valve 3 to the decompressed state can be reliably reduced by moving to the position where it rides on the valve, and the valve lift amount when the intake valve 3 is opened by rotating the cam 5 at the start is excessive. It can reliably avoid made it to.

  Next, FIG. 2 shows a second embodiment.

  In this second embodiment, an intake valve 3 'provided for an intake port 2' in a cylinder head 1 'and held closed by a spring 4', and a camshaft 6 rotating in synchronization with a crankshaft. The rocking member 9 'is placed between the upper cam 5' and the lower surface of one end of the rocking member 9 'is in contact with the upper end of the intake valve 3'. The cam 5 'is disposed so as to contact the upper surface of the portion, the other end of the swinging member 9' is extended away from the cam 5 ', and a fulcrum member is provided below the extension. 13 'is arranged so as to rotate about the pin shaft 14', and a contact portion 20 'at the upper end of the fulcrum member 13' is provided on the lower surface of the swinging member 9 '. When the cam 5 'rotates, the rocking member 9' is brought into contact with the fulcrum member 13 '. The intake valve 3 'is configured to open and act against the spring 4' by swinging with the contact point 20 'contacting the sliding surface 9a' as a fulcrum S 'of the rotation center. is doing.

  The sliding surface 9a 'of the swing member 9' is an arc surface having a radius R 'centered on the pin shaft 14' of the fulcrum member 13 '.

  In this configuration, the fulcrum member 13 'is moved to the cam 5' side from an intermediate load range indicated by a solid line when the internal combustion engine is in a high load range by an actuator (not shown) or the like. From the force point F ′ at which the cam 5 ′ contacts the swing member 9 ′, the contact portion 15 ′ at the tip of the fulcrum member 13 ′ contacts the sliding surface 9 a ′ of the swing member 9 ′. The force point length to the fulcrum S ′ is shortened from the force point length X0 ′ to X1 ′ in the middle load region, and the swing angle of the swing member 9 ′ is increased. The intake valve 3 'is operated by opening it to a large valve lift.

  Further, the fulcrum member 13 'is moved by a not-shown actuator or the like in a direction away from the cam 5' from the state of the medium load region shown by the solid line when the internal combustion engine is in a low load region. From the force point F ′ at which the cam 5 ′ contacts the moving member 9 ′, the contact point 15 ′ at the tip of the fulcrum member 13 ′ contacts the sliding surface 9 a ′ of the swinging member 9 ′. The power point length up to S ′ is increased from the power point length X0 ′ to X2 ′ in the middle load region, and the swing angle of the swing member 9 ′ is decreased. The valve 3 'is opened and operated with a small valve lift.

  Thus, the valve lift amount when the intake valve 3 'is opened and operated can be controlled to be large in the high load region and small in the low load region according to the load of the internal combustion engine.

  A fulcrum member 13 'that contacts the sliding surface 9a' of the swing member 9 'is configured to move further outside the low load region by an actuator (not shown) or manual operation. On the other hand, a protruding portion 20 'is provided on the sliding surface 9a' of the swinging member 9 'beyond the low load region, and the fulcrum member 13' is moved further outward beyond the low load region. In this case, the contact portion 15 'of the fulcrum member 13' is configured to ride on the raised portion 20 '.

When the operation of the internal combustion engine is stopped, by moving the fulcrum member 13 'so as to ride over the raised portion 20' beyond the low load region, the swing member 9 ' Since the intake valve 3 'is rotated in the opening direction by the amount of the contact portion 15' of the fulcrum member 13 'riding on the portion 20', this rotation opens the intake valve 3 'to the decompressed state. Can do.

  In addition, although each above-mentioned embodiment was a case where it controlled according to load, this invention is not restricted to this, When controlling according to rotation speed, or controlling according to load and rotation speed Needless to say, it may be configured.

It is a figure which shows 1st Embodiment in this invention. It is a figure which shows 2nd Embodiment in this invention.

Explanation of symbols

1, 1 'Cylinder head 2, 2' Intake port 3, 3 minutes Intake valve 4, 4 'Intake valve spring 5, 5' Cam 6, 6 'Cam shaft 8 Rocker arm 9, 9' Swing member 9a, 9a ' Sliding surface 13, 13 ′ fulcrum member 20, 20 ′ raised portion

Claims (2)

A oscillating member is provided between a cam rotating in synchronization with the crankshaft and an intake valve or an exhaust valve. With the abutment portion as a fulcrum of the rotation center, the cam is rotated so as to open and operate the intake valve or exhaust valve, and the fulcrum member is in contact with the sliding surface of the fulcrum member. A valve operating mechanism in an internal combustion engine configured to move along the sliding surface according to an operating state in the internal combustion engine;
The fulcrum member is configured such that a contact portion of the fulcrum member with respect to the sliding surface can move beyond the range of the entire operating range of the internal combustion engine on the sliding surface. A raised portion is provided on the moving surface so that when the contact portion moves beyond the range of the entire operating range of the internal combustion engine, the contact portion rides up, and the contact portion rides on the raised portion. The decompression device in the internal combustion engine, wherein the swing member is configured to rotate in a direction to open the intake valve or the exhaust valve .   The fulcrum member according to claim 1, wherein the fulcrum member moves in a direction away from the cam when a contact portion of the fulcrum member with respect to the sliding surface is in a low load or low rotation range in an internal combustion engine. The internal combustion engine is configured to move in a direction approaching the cam when in a high rotation range, and further, the raised portion is provided in a portion of the sliding surface beyond the low load or low rotation range. Decompression device in the engine.

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