JP2006258059A - Valve driving device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve driving device of an internal combustion engine having a rush adjuster for eliminating valve clearance between a sliding contact surface of a valve and a sliding contact surface of a cam (or a rocker arm), in the valve driving device for forcibly driving the valve. <P>SOLUTION: In this valve driving device 87 of the internal combustion engine 10A, a clearance adjusting part 76 is integrally arranged in an end part of the valve 61 of the internal combustion engine 10A, and this clearance adjusting part 76 is formed with a valve opening sliding surface 71 for pressing for opening the valve 61 and a valve closing sliding surface 72 for pressing for closing the valve 61, and the valve 61 is forcibly opened and closed by respectively pressing these valve opening sliding surface 71 and valve closing sliding surface 72 by the rocker arms 83 and 84. The hydraulic rush adjuster 62 is constituted for eliminating clearance between the sliding contact surface 83a of the rocker arm 83 and the valve opening sliding surface 71 and clearance between the sliding contact surface 84a of the rocker arm 84 and the valve closing sliding surface 72 by the clearance adjusting part 76. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement of a valve drive device for an internal combustion engine.

2. Description of the Related Art As a conventional valve drive device for an internal combustion engine, a follower provided in a valve stem is forcibly moved by a cam to open and close a valve (see, for example, Patent Document 1) Built in one of two rocker arms It is known that the lash adjuster is applied to the end of the valve shaft and the valve is forcibly opened and closed with the other rocker arm (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 9-4423 JP 61-11408 A

FIG. 2 of Patent Document 1 will be described with reference to FIG. In addition, the code | symbol was reassigned.
FIG. 7 is a perspective view showing a conventional valve drive device for an internal combustion engine. A cam groove 202 is formed on the side surface of the cam 201, and a follower 206 is provided at the end of the stem 204 of the intake valve 203. Is inserted into the cam groove 202 and the intake valve 203 is forcibly driven by the cam 201.

FIG. 2 of Patent Document 2 will be described with reference to FIG. 8 below. In addition, the code | symbol was reassigned.
FIG. 8 is an explanatory view showing a conventional valve drive device for an internal combustion engine. A lash adjuster 214 is built in the tip 213 of a valve-opening rocker arm 212 that swings about a shaft 211, and a lash adjuster is placed at the tip of the valve 216. The front end of the valve opening rocker arm 212 is brought into contact with the rear end portion 217 of the valve opening rocker arm 212, and the front end portion 223 of the valve closing rocker arm 222 swinging about the shaft 221 is connected to the valve rod 224 of the valve 216. It is shown that the outer peripheral surface of the valve closing cam 228 is brought into contact with the rear end 227 of the valve closing rocker arm 222 against the collar 226 provided in FIG.

  In FIG. 7, the intake valve 203 is directly driven by the cam 201 via the follower 206. However, since the intake valve 203 is not structured to absorb thermal expansion or contraction, the intake valve 203 is thermally contracted. It may be difficult to absorb the impact when seated or to ensure sealing performance when thermally expanded.

  In FIG. 8, the lash adjuster 214 can absorb the thermal expansion and contraction of the valve 216, but the valve opening rocker arm 212 is provided with a hole for attaching the lash adjuster 214, or oil that supplies oil to the lash adjuster 214. It is necessary to open the path 231 and the cost is increased.

  Further, when the valve 216 is thermally expanded, the collar 226 that lifts the valve 216 moves upward, so that a gap is formed between the tip 223 of the valve closing rocker arm 222 and the collar 226, and noise such as valve beating sound is generated. Will occur.

  An object of the present invention is a valve drive device for forcibly driving a valve, and is a valve drive for an internal combustion engine having a lash adjuster that eliminates a valve clearance between the sliding contact surface of the valve and the sliding contact surface of the cam (or rocker arm). To provide an apparatus.

  The invention according to claim 1 is provided with a follower integrally provided at an end of the intake / exhaust valve of the internal combustion engine, and a valve opening side pressing surface as a sliding contact surface that is pressed to open the intake / exhaust valve on the follower. And a valve closing side pressing surface as a sliding contact surface that is pressed to close the intake / exhaust valve, and these valve opening side pressing surface and valve closing side pressing surface are pressed by the sliding contact surface of the cam or the rocker arm. A hydraulic lash adjuster that eliminates a gap between a cam or a rocker arm and a valve-opening side pressing surface and a valve-closing side pressing surface in a valve drive device for an internal combustion engine that forcibly opens and closes an intake / exhaust valve It is characterized by comprising.

A follower is integrally provided at the end of the intake / exhaust valve, and the valve opening pressing surface of the follower is pressed with a cam or a rocker arm to forcibly open the intake / exhaust valve, and the valve closing pressing surface of the follower Is forcibly closed with a cam or rocker arm.
By configuring the hydraulic lash adjuster with the follower, there is no gap between the cam or rocker arm and the valve opening side pressing surface, and there is no gap between the cam or rocker arm and the valve closing side pressing surface.

  According to a second aspect of the present invention, there is provided an intermediate body in which a follower is attached to an end of an intake / exhaust valve, a valve-opening follower which is movably attached to the intermediate body and has a valve-opening pressing surface, and an intermediate body And a valve-closed follower having a valve-closing pressure surface, and the follower is supplied with oil from the intake / exhaust valve side and has a valve-opening pressure surface and a valve-closing pressure surface. Two oil chambers for generating hydraulic pressure to be pressed against the cam or the rocker arm are provided.

Oil is supplied to one of the oil chambers, and the valve-opening side follower having the valve-opening side pressing surface is moved relative to the intermediate body attached to the end of the intake / exhaust valve so that the valve-opening side pressing surface is moved to the cam or rocker arm Press on.
Also, oil is supplied to the other oil chamber, and the valve-closing follower having the valve-closing pressure surface is moved relative to the intermediate body to press the valve-closing pressure surface against the cam or the rocker arm.

The invention according to claim 3 is characterized in that in the follower, the pressing force for pressing the valve closing side pressing surface against the cam or the rocker arm is larger than the pressing force for pressing the valve opening side pressing surface against the cam or the rocker arm.
If the pressure receiving area of the oil chamber that moves the valve closing side pressing surface is larger than the pressure receiving area of the oil chamber that moves the valve opening side pressing surface, the pressing force that presses the valve closing side pressing surface against the cam or rocker arm is increased. It becomes possible to make it larger than the pressing force pressing the valve-opening side pressing surface.

In the invention according to claim 1, since the follower constitutes a hydraulic lash adjuster, the clearance between the sliding contact surface on the valve side and the sliding contact surface on the cam (or rocker arm) side can be reduced to zero, and the valve sound and the like. Noise reduction and impact during valve seating can be eliminated and sealing can be performed reliably.
Further, since the lash adjuster is constituted by the follower of the valve, it is possible to reduce the cost and weight by downsizing, and to increase the degree of freedom in designing the valve driving device.

  The invention according to claim 2 includes two oil chambers that generate hydraulic pressures for pressing the valve-opening side pressing surface and the valve-closing side pressing surface against the cam or the rocker arm, respectively, so that the pressure receiving area of these two oil chambers is arbitrarily set It can be set, and the degree of freedom in designing the pressing force to the cam or the rocker arm can be increased.

  In the invention according to claim 3, the pressure receiving area of one oil chamber for pressing the valve closing side pressing surface against the cam or rocker arm, and the pressure receiving area of the other oil chamber for pressing the valve opening side pressing surface against the cam or rocker arm By making it larger than this, the intake and exhaust valves can be reliably seated.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a sectional view of a valve operating mechanism employing a hydraulic lash adjuster (first embodiment) according to the present invention. The valve operating mechanism 10 includes a valve guide 12 provided on a cylinder head 11 of an internal combustion engine 10A, A valve 61 (which is an intake valve or an exhaust valve) movably inserted into the valve guide 12, a lash adjuster 62 of the present invention provided at an end of the valve 61, and a rocker shaft 81 attached to the cylinder head 11. , 82, rocker arms 83, 84 that are swingably attached to these rocker shafts 81, 82 and sandwich the lash adjuster 62 at one end thereof, and a camshaft 86 that drives the other ends of these rocker arms 83, 84, The valve is forcibly opened and closed.

  The valve operating mechanism 10 excluding the valve 61 constitutes a valve driving device 87. That is, the valve driving device 87 includes the valve guide 12, the lash adjuster 62, the rocker shafts 81 and 82, the rocker arms 83 and 84, and the camshaft 86.

  The camshaft 86 includes a valve opening cam 88 for opening the valve 61 and a valve closing cam 91 for closing the valve 61, and the lash adjuster 62 slides on a sliding contact surface 83 a provided at one end of the rocker arm 83. A valve opening sliding surface 71 serving as a sliding contact surface and a valve closing sliding surface 72 serving as a sliding contact surface slidably contacting a sliding contact surface 84 a provided at one end of the rocker arm 84 are provided.

  Here, 21 is a combustion chamber, 22 is a valve seat, 23 is a port (intake port or exhaust port), 24 is an oil passage on the oil pump side, and 26 is an oil supply extending from the oil passage 24 to the valve guide 12 side. A passage 61a is a shaft portion of the valve 61, 88a is a base circle of the valve opening cam 88, 88b is a cam nose of the valve opening cam 88, 91a is a base circle of the valve closing cam 91, and 91b is a base circle 91a of the valve closing cam 91. It is a cam hollow part hollowed inward in the diameter.

  FIG. 2 is a cross-sectional view of the main part of the end portion of the valve shaft showing the hydraulic lash adjuster (first embodiment) according to the present invention. The lash adjuster 62 has the first oil hole 36 and the valve 61 closed. An annular groove 74 formed in the outer peripheral surface of the shaft portion 61a of the valve 61 so as to communicate with the first oil hole 36, a vertical hole 75 formed in the end portion of the shaft portion 61a, and the vertical hole 75 and the annular groove 74. The second oil hole 41 communicates each of the two and a clearance adjustment portion 76 for adjusting the valve clearance.

  The clearance adjusting portion 76 is configured to movably fit the plunger portion 101 to an intermediate body 77 screwed to the outer peripheral surface of the end portion of the shaft portion 61a and a large-diameter hole 78 constituting the end portion side of the vertical hole 75 and to move the intermediate portion. 77, the valve-opening side body 104 that forms the first oil chamber 103, and the valve-closing body 106 that is movably fitted to the outer peripheral surface of the shaft portion 61a and that forms the second oil chamber 105 with the intermediate portion 77. A hollow portion 107 provided in the plunger portion 101, a plunger portion first oil passage 108 opened in the valve-opening body 104 for communicating the hollow portion 107 and the first oil chamber 103, and a first oil chamber 103, the first orifice 111 communicating with the outside, the plunger portion second oil passage 112 for communicating the hollow portion 107 with the outer peripheral surface side of the plunger portion 101, and the plunger portion second oil passage 112 serving as the outer periphery of the shaft portion 61a. A third oil passage 113 communicating with the second oil passage 113, a fourth oil passage 114 and a fifth oil passage 115 formed in the valve-closing body 106 for communicating the second oil chamber 105 with the third oil passage 113, The second orifice 116 communicates from the two oil chambers 105 to the outside.

The shaft portion 61 a includes a small diameter portion 121, a male screw 122 formed in the small diameter portion 121, and a step portion 123 provided at the end of the small diameter portion 121 at the end.
The intermediate body 77 is fitted into the small diameter hole 125 to be fitted into the small diameter part 121 of the shaft part 61 a, the female screw 126 to be screwed to the male screw 122, the end part 127 applied to the stepped part 123, and the valve opening side body 104. The inner O-ring groove 131 formed on the first outer peripheral surface 128, the outer O-ring groove 133 formed on the second outer peripheral surface 132 fitted to the valve opening side body 104, and the female screw 126 to the first outer peripheral surface 128. A doughnut-shaped first wall surface 134 extending from the end portion 127 to the second outer peripheral surface 132.

  The valve-opening side body 104 includes the above-described valve-opening sliding surface 71 having a circular cross section, an annular protrusion 138 formed on the back surface of the valve-opening sliding surface 71, and an inner side of the annular protrusion 138. A doughnut-shaped third wall surface 141 provided on the inner surface 77 and a first inner peripheral surface 142 provided on the inner side of the annular protrusion 138 for movably fitting to the first outer peripheral surface 128 of the intermediate body 77, The O-ring 143 fitted in the O-ring groove 131 seals between the first inner peripheral surface 142 and the first outer peripheral surface 128, and the first oil chamber 103 is formed by the first wall surface 134 and the third wall surface 141. To do.

  The valve closing side body 106 is movably fitted to the cylindrical portion 145 to be fitted to the shaft portion 61a, the step portion 146 to be brought into contact with the end portion 127 of the intermediate body 77, and the second outer peripheral surface 132 of the intermediate body 77. The second inner peripheral surface 147 and the second outer peripheral surface are formed by an O-ring 151 that includes a second inner peripheral surface 147 and a fourth wall surface 148 extending from the step portion 146 to the second inner peripheral surface 147 and is fitted in the outer O-ring groove 133. The space between the surfaces 132 is sealed, and the second wall surface 136 and the fourth wall surface 148 form the second oil chamber 105.

The third wall surface 141 of the valve opening side body 104 is a portion having an inner diameter P1 and an outer diameter P2, and the fourth wall surface 148 of the valve closing side body 106 is an inner diameter C1 and an outer diameter C2. Part. Receiving area SP from the oil of the third wall 141, SP = π × (P2- P1) 2/4 , and the pressure receiving area SC of the oil in the fourth wall 148, SC = π × (C2- C1) 2 / 4, and the relationship between the pressure receiving area SP and the pressure receiving area SC is SC> SP.

Next, the operation of the lash adjuster 62 described above will be described.
3 (a) and 3 (b) are operation diagrams showing the operation of the hydraulic lash adjuster (first embodiment) according to the present invention.
In (a), when the valve 61 is closed, as indicated by arrows G, H, and J, the oil passes through the vertical hole 75, the hollow portion 107, and the plunger portion first oil passage 108 into the first oil chamber 103. A small amount of oil flows in and leaks from the first orifice 111 to the outside as indicated by an arrow K.

  As a result, the hydraulic pressure in the first oil chamber 103 increases, and this hydraulic pressure acts on the third wall surface 141. Therefore, a pressing force F1 indicated by an arrow is generated in the valve-opening body 104, and the valve-opening body 104 is The valve opening side sliding contact surface 71 of the valve opening side body 104 presses against the sliding contact surface 83a of the rocker arm 83 by slightly moving in the direction of the white arrow L with respect to the portion 61a.

  Further, as indicated by arrows G, N, and P, the oil passes through the vertical hole 75, the hollow portion 107, the plunger portion second oil passage 112, the third oil passage 113, the fourth oil passage 114, and the fifth oil passage 115. As shown by the arrow Q, a small amount of oil leaks into the second oil chamber 105 from the second orifice 116 to the outside.

  As a result, the hydraulic pressure in the second oil chamber 105 increases, and this hydraulic pressure acts on the fourth wall surface 148, so that a pressing force F2 indicated by an arrow is generated in the valve-closing body 106, and the valve-closing body 106 is The valve closing side sliding contact surface 72 (see FIG. 1) of the valve closing side body 106 presses against the sliding contact surface 84a of the rocker arm 84.

  The pressing force F1 and the pressing force F2 described above are such that the fourth wall surface 148 has a larger pressure receiving area than the third wall surface 141. Therefore, the pressing force F2> the pressing force F1, and the closing force F2 on the valve closing side is opened. It becomes larger than the pressing force F1 on the valve side, and the valve 61 can be closed reliably.

  In (b), when the valve 61 is opened, the valve opening body 104 and the oil in the first oil chamber 103 are passed through the valve opening body 104 by the pressing force from the sliding contact surface 83a of the rocker arm 83. Since the connected intermediate body 77 and the shaft portion 61a move as indicated by the white arrow T, the annular groove 74 of the shaft portion 61a moves relative to the first oil hole 36 of the valve guide 12, and the first oil hole 36 and the annular groove 74 do not communicate with each other, and oil is not supplied into the vertical hole 75, but the oil in the vertical hole 75 and the hollow portion 107 only slightly leaks from the first orifice 111. Is kept at a high hydraulic pressure, and the pressing force by the rocker arm 83 can be transmitted from the valve opening body 104 to the shaft portion 61a, so that the valve 61 can be opened.

  As described above with reference to FIGS. 1 and 2, the present invention firstly provides a clearance adjusting portion 76 as a follower integrally at the end of a valve 61 as an intake / exhaust valve of the internal combustion engine 10A. Valve opening sliding surface 71 as a valve opening side pressing surface that is pressed to the clearance adjusting portion 76 to open the valve 61, and valve closing sliding surface as a valve closing side pressing surface that is pressed to close the valve 61 The valve of the internal combustion engine 10 </ b> A that forcibly opens and closes the valve 61 by pressing the valve-opening sliding surface 71 and the valve-closing sliding surface 72 with cams or rocker arms 83 and 84. A hydraulic lash adjuster that eliminates a gap between the cam or rocker arm 83 and the valve-opening sliding surface 71 and a gap between the cam or rocker arm 84 and the valve-closing sliding surface 72 by the clearance adjusting unit 76. 62 And said that you configure.

Since the clearance adjusting portion 76 constitutes the hydraulic lash adjuster 62, the sliding contact surface on the valve 61 side (that is, the valve opening sliding surface 71 and the valve closing sliding surface 72) and the rocker arm 83 (and the rocker arm 84) slide. Clearance with the contact surface can be reduced to zero, noise reduction such as valve sound, no impact when seated, and reliable sealing.
In addition, since the lash adjuster 62 is configured by the clearance adjustment portion 76 of the valve 61, cost reduction and weight reduction can be achieved by downsizing, and the degree of freedom in designing the valve driving device 87 can be increased.

  Secondly, according to the present invention, a clearance adjusting portion 76 is attached to an end portion of the valve 13, and a valve-opening follower having a valve-opening sliding surface 71 and a movably attached to the intermediate body 77. The valve opening side body 104 and the valve closing side body 106 as a valve closing side follower which is movably attached to the intermediate body 77 and has a valve closing sliding surface 72 are provided. A first oil chamber 103 as two oil chambers that receives oil supply from the valve 13 side and generates hydraulic pressure that presses the valve-opening sliding surface 71 and the valve-closing sliding surface 72 against cams or rocker arms 83 and 84, respectively. And a second oil chamber 105.

Since the first oil chamber 103 and the second oil chamber 105 for generating hydraulic pressure for pressing the valve-opening sliding surface 71 and the valve-closing sliding surface 72 against the cams or rocker arms 83 and 84 are provided, these two oil chambers are provided. The pressure receiving areas 103 and 105 can be set arbitrarily, and the degree of freedom in designing the pressing force to the cams or rocker arms 83 and 84 can be increased.

  Third, according to the present invention, the clearance adjusting unit 76 uses a pressing force F2 that presses the valve-closing sliding surface 72 against the cam or rocker arm 84, and a pressing force F1 that presses the valve-opening sliding surface 71 against the cam or rocker arm 83. It is also characterized by a larger size.

  The pressure receiving area SC of one second oil chamber 105 for pressing the valve closing sliding surface 72 against the cam or rocker arm 84, and the other first oil for pressing the valve opening sliding surface 71 against the cam or rocker arm 83. By making it larger than the pressure receiving area SP of the chamber 103, the valve 13 can be reliably closed.

FIG. 4 is a cross-sectional view of a valve operating mechanism employing a hydraulic lash adjuster (second embodiment) according to the present invention. The same components as those in the first embodiment shown in FIG. Is omitted.
The valve mechanism 60 includes a valve guide 12, a valve (an intake valve or an exhaust valve) 61 movably inserted in the valve guide 12, and a lash adjuster 62 of the present invention provided at an end of the valve 61. And a forced valve opening / closing type comprising a camshaft 63 for opening / closing the valve 61 via the lash adjuster 62.

  The valve operating mechanism 60 excluding the valve 61 constitutes a valve driving device 64. That is, the valve driving device 64 includes the valve guide 12, the lash adjuster 62, and the cam shaft 63.

  The camshaft 63 includes a valve-opening cam 66 for opening the valve 61 and a valve-closing cam 67 for closing the valve 61, and the lash adjuster 62 is opened in sliding contact (that is, circumscribed) with the valve-opening cam 66. A valve sliding surface 71 and a valve closing sliding surface 72 slidably contacting (ie, inscribed) the valve closing cam 67 are provided. Reference numeral 66a denotes a base circle of the valve opening cam 66, 66b denotes a cam nose of the valve opening cam 66, 66c denotes a sliding contact surface of the base circle 66a that comes into sliding contact with the valve opening sliding surface 71, and 66d denotes a valve opening sliding surface 71. The sliding contact surface of the cam nose 66b that slides on, 67a is a base circle of the valve closing cam 67, 67b is a large diameter cam portion that is located radially outward from the base circle 67a of the valve closing cam 67, and 67c is a sliding valve closing valve. A sliding surface of the base circle 67a that is in sliding contact with the surface 72, 67d is a sliding contact surface of the cam large diameter portion 67b that is in sliding contact with the valve closing sliding surface 72.

  FIG. 5 is a perspective view of the camshaft according to the present invention (second embodiment). The camshaft 63 includes two shaft portions 155 and 156 and a cam assembly provided between the shaft portions 155 and 156. 157 for opening and closing the two valves 61.

  6 is a cross-sectional view taken along line 6-6 of FIG. The valve-closing cam 161 having an E-shaped cross section and a valve-opening cam 66 sandwiched between the valve-closing cam 67 and the valve-closing cam 161 include shaft portions 155, 156, valve-closing cams 67, 67, The cam 161 and the valve opening cams 66 and 66 were connected as separate bodies.

  The valve closing cam 67 and the valve closing cam 161 are each provided with a valve closing cam surface 162, and the valve opening cam 66 is provided with a valve opening cam surface 163, and the valve closing cam surface 162 is provided for closing the lash adjuster 62. The sliding surfaces 72 and 72 are applied, and the valve opening sliding surface 71 of the lash adjuster 62 is applied to the valve opening cam surface 163. Reference numeral 165 denotes an axis of the camshaft 63.

  In the present embodiment, as shown in FIG. 1, the valve 61 is opened and closed with the lash adjuster 62 sandwiched between the two rocker arms 83 and 84. However, the present invention is not limited to this, and one end of one rocker arm is provided. Alternatively, a U-shaped portion may be provided, the lash adjuster 62 may be sandwiched between the U-shaped portions, and the valve 61 may be opened and closed by applying the valve opening cam 88 and the valve closing cam 91 to the other end of the rocker arm.

  The valve drive device of the present invention is suitable for a valve operating mechanism (rocker arm type and forced valve opening / closing type) of an internal combustion engine.

It is sectional drawing of the valve operating mechanism which employ | adopted the hydraulic lash adjuster (1st Embodiment) which concerns on this invention. It is principal part sectional drawing by the side of the valve shaft part end which shows the hydraulic lash adjuster (1st Embodiment) which concerns on this invention. It is an operation view showing an operation of the hydraulic lash adjuster (first embodiment) according to the present invention. It is sectional drawing of the valve mechanism which employ | adopted the hydraulic lash adjuster (2nd Embodiment) which concerns on this invention. It is a perspective view (2nd Embodiment) of the cam shaft which concerns on this invention. FIG. 6 is a sectional view taken along line 6-6 of FIG. It is a perspective view which shows the valve drive apparatus of the conventional internal combustion engine. It is explanatory drawing which shows the valve drive apparatus of the conventional internal combustion engine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10A ... Internal combustion engine, 13 ... Intake / exhaust valve (valve), 62 ... Rush adjuster, 64, 87 ... Valve drive device, 66, 67 ... Cam (valve opening cam, valve closing cam), 71 ... Valve opening side pressing surface ( Valve opening sliding surface), 72 ... Valve closing side pressing surface (valve closing sliding surface), 76 ... Follower (clearance adjusting portion), 77 ... Intermediate, 83, 84 ... Rocker arm, 103, 105 ... Oil Chamber (first oil chamber, second oil chamber), 104 ... valve opening side follower (valve opening side body), 106 ... valve closing side follower (valve closing side body), F1, F2 ... pressing force.

Claims (3)

A follower is integrally provided at the end of the intake / exhaust valve of the internal combustion engine, and the follower is pressed to open the intake / exhaust valve and to open and close the intake / exhaust valve. A valve driving device for an internal combustion engine that forms a valve closing side pressing surface and forcibly opens and closes the intake and exhaust valves by pressing the valve opening side pressing surface and the valve closing side pressing surface with a cam or a rocker arm. There,
The valve drive device for an internal combustion engine, wherein the follower constitutes a hydraulic lash adjuster that eliminates a gap between the cam or rocker arm and the valve-opening side pressing surface and the valve-closing side pressing surface.   The follower is attached to an end of the intake / exhaust valve, is movably attached to the intermediate, and has a valve-opening follower having the valve-opening pressing surface, and is movably attached to the intermediate. And a valve-closed follower provided with the valve-closing pressure surface, and receives oil supplied from the intake / exhaust valve side to press the valve-opening pressure surface and the valve-closing pressure surface against the cam or the rocker arm, respectively. The valve drive device for an internal combustion engine according to claim 1, further comprising two oil chambers for generating   2. The follower according to claim 1, wherein a pressing force for pressing the valve closing side pressing surface against the cam or the rocker arm is larger than a pressing force for pressing the valve opening side pressing surface against the cam or the rocker arm. The valve drive device for an internal combustion engine according to claim 2.

Images