JP2017101640A - Variable valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively improve the fuel economy of an engine by properly adjusting a discharge amount of a pump.SOLUTION: A variable valve device comprises: a valve opening/closing mechanism 10 which changes at least one opening/closing characteristic of an intake valve or an exhaust valve by the hydraulic pressure of a working fluid to be supplied; a changeover valve 30 which can be selectively switched to a first state in which the supply of the working fluid to the valve opening/closing mechanism 10 is permitted, and a second state in which the supply of the working fluid to the valve opening/closing mechanism 10 is blocked; and a variable capacity type pump 40 which is driven by the power of an engine, increases a discharge amount of the working fluid which is supplied to the valve opening/closing mechanism 10 in the first state, and decreases the discharge amount of the working fluid which is supplied to the valve opening/closing mechanism 10 in the second state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a variable valve gear.

  Conventionally, various variable valve operating devices that change the opening / closing characteristics of the intake / exhaust valves of an engine in accordance with the engine operating state have been put into practical use. In a general cam-switching variable valve gear, multiple cams with different cam profiles are selected by appropriately adjusting the hydraulic pressure supplied to the valve opening / closing mechanism from a hydraulic supply source to high or low pressure using a spool valve. (For example, refer patent document 1).

JP 2002-339711 A

  By the way, in the conventional variable valve operating apparatus using the above-described spool valve, the hydraulic oil discharged from the pump driven by the engine power is discharged into the cylinder head (drain) without supplying it to the valve opening / closing mechanism at low oil pressure. )doing. In other words, when the oil pressure is low, the pump drive can be lowered and wasteful drainage of the hydraulic oil can be stopped, but the drive of the pump is maintained with the same amount of work as that at the time of low oil pressure. There is a possibility of causing a decrease in fuel efficiency.

  It is an object of the disclosed technology to effectively improve the fuel efficiency of an engine by appropriately adjusting the discharge amount of a pump.

  In the disclosed technique, a valve opening / closing mechanism that changes an opening / closing characteristic of at least one of an intake valve and an exhaust valve of an engine according to a hydraulic pressure of a supplied hydraulic oil, and a first state that allows supply of the hydraulic oil to the valve opening / closing mechanism. Alternatively, a switching valve that can be selectively switched to a second state that cuts off the supply of hydraulic oil to the valve opening / closing mechanism, and an operation that is driven by the engine power and that is supplied to the valve opening / closing mechanism in the first state And a variable displacement pump that increases the amount of oil discharged and decreases the amount of hydraulic oil supplied to the valve opening / closing mechanism in the second state.

  The variable displacement pump is a variable displacement vane pump in which a cam ring is provided on an outer peripheral side of a rotor having a plurality of vanes that can advance and retreat in a radial direction so as to be able to swing eccentrically. The amount of eccentricity of the cam ring may be increased, and the amount of eccentricity of the cam ring with respect to the rotor in the second state may be reduced.

  A first oil supply channel for connecting the variable displacement pump and the switching valve to supply hydraulic oil from the variable displacement pump to the switching valve; and a connection between the switching valve and the valve opening / closing mechanism. A second oil supply flow path for supplying hydraulic oil from the switching valve to the valve opening / closing mechanism, a connection between the first oil supply flow path and the second oil supply flow path bypassing the switching valve; And a bypass channel provided with an orifice for narrowing the channel at the predetermined location.

  According to the disclosed technology, the fuel consumption performance of the engine can be effectively improved by appropriately adjusting the discharge amount of the pump.

It is a typical whole block diagram which shows the variable valve apparatus which concerns on one Embodiment of this invention. In FIG. 1, it is a figure explaining the state which canceled the connection of the rocker arm.

  Hereinafter, a variable valve operating apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  As shown in FIG. 1, the variable valve operating apparatus 1 includes a valve opening / closing mechanism 10 disposed on a cylinder head of a diesel engine (hereinafter simply referred to as an engine), an ON / OFF switching valve 30, and a variable displacement vane pump 40. And is configured. In the following description, the valve opening / closing mechanism 10 is applied to an exhaust valve, but it can also be applied to an intake valve. In FIG. 1, the valve opening / closing mechanism 10 shows only one cylinder, and the valve opening / closing mechanisms of the other cylinders are not shown.

  The valve opening / closing mechanism 10 includes an exhaust camshaft 11 rotatably supported by a bearing (not shown) and rotated by power transmitted from a crankshaft, and a pair of first and second cam profiles provided on the exhaust camshaft 11 with different cam profiles. Second cams 12A, 12B, an exhaust rocker shaft 13 extending in parallel with the exhaust camshaft 11, and a pair of swingable first and second rocker arms 14A fixed at one end to the exhaust rocker shaft 13 , B and a connecting pin 20 for selectively connecting the first and second rocker arms 14A, B.

  The first cam 12A is in contact with the slipper surface of the first rocker arm 14A, and the second cam 12B is in contact with the slipper surface of the second rocker arm 14B. Further, the other end side of the first rocker arm 14A is bifurcated and the stem ends 16A, B of the pair of exhaust valves are in contact with the lower surfaces thereof.

  The exhaust rocker shaft 13 is formed with a first oil passage 13A extending in the axial direction and a second oil passage 13B extending in the radial direction. A discharge port 31B of an ON / OFF switching valve 30 to be described later is connected to the first oil passage 13A via a second oil supply pipe 51.

  The second rocker arm 14B is provided with a pin accommodation hole 21 that slidably accommodates the connecting pin 20. Between the bottom surface of the pin accommodation hole 21 and the side surface of the connecting pin 20, an oil chamber 22 is formed in which hydraulic oil is supplied from the first oil passage 13A through the second oil passage 13B. The first rocker arm 14 </ b> A is provided with a pin receiving hole 25 that receives the spring 24 and can receive the distal end side of the connecting pin 20. The first rocker arm 14A is formed with an air vent hole 26 that allows the pin receiving hole 25 to communicate with the outside.

  When the hydraulic oil is supplied to the oil chamber 22, the connecting pin 20 is moved against the urging force of the spring 24 by the hydraulic pressure, and the distal end side of the connecting pin 20 is engaged with the pin receiving hole 25, whereby the first rocker arm 14 </ b> A. Are connected to the second rocker arm 14B. On the other hand, when the supply of the hydraulic oil to the oil chamber 22 is interrupted, the connecting pin 20 is pushed back by the urging force of the spring 24 and is accommodated in the pin accommodation hole 21, and the first rocker arm 14A and the second rocker arm 14B. The connection with is released.

  The ON / OFF switching valve 30 includes a valve body 31 provided with a suction port 31A and a discharge port 31B, and a piston 32 that is slidably accommodated in the valve body 31 and can close the suction port 31A and the discharge port 31B. A return spring 33 that urges the piston 32 in the valve closing direction and a solenoid portion 34 including an electromagnetic coil 34 </ b> A provided in the valve body 31 are configured.

  The suction port 31A is connected via a first oil supply pipe 50 to a discharge port 41B of a variable displacement vane pump 40 described later. The discharge port 31 </ b> B is connected to the first oil passage 13 </ b> A of the exhaust rocker shaft 13 via the second oil supply pipe 51. The first oil supply pipe 50 and the second oil supply pipe 51 are connected by a bypass passage pipe 52 that bypasses the ON / OFF switching valve 30. The bypass channel pipe 52 is provided with an orifice 53 for narrowing the channel.

  When the current to the electromagnetic coil 34A is turned on, the piston 32 moves in the valve opening direction against the urging force of the return spring 33 and causes the suction port 31A and the discharge port 31B to communicate with each other, whereby the first oil supply pipe 50 To the second oil supply pipe 51 is allowed to be supplied. On the other hand, when the current of the electromagnetic coil 34A is turned off, the piston 32 moves in the valve closing direction by the urging force of the return spring 33 to close the suction port 31A and the discharge port 31B. The supply of hydraulic oil to the second oil supply pipe 51 is cut off.

  The variable displacement vane pump 40 includes a pump housing 41 provided with a suction port 41A and a discharge port 41B, a rotor 42 to which rotational force is transmitted from a crankshaft (not shown), and a slit groove of the rotor 42 that is inserted in a radial direction. A plurality of vanes 43 that can advance and retreat, a cam ring 45 that is provided on the outer peripheral side of the rotor 42 so as to be able to swing eccentrically, and the tip of each vane 43 is in sliding contact with the inner peripheral surface, and the amount of eccentricity of the cam ring 45 with respect to the rotor 42 increases. A spring 46 that urges the cam ring 45 in a direction and a piston 47 that presses the cam ring 45 in a direction that reduces the amount of eccentricity by the hydraulic pressure of the hydraulic chamber 48 are provided.

  An oil introduction pipe 61 for introducing hydraulic oil from the oil pan 60 is connected to the suction port 41 </ b> A of the pump housing 41. A suction port 31 </ b> A of the ON / OFF switching valve 30 is connected to the discharge port 41 </ b> B of the pump housing 41 via the first oil supply pipe 50 described above. The hydraulic chamber 48 is supplied with a gallery hydraulic pressure from an oil gallery of an engine (not shown).

  When the cam ring 45 is moved in the eccentric direction by the urging force of the spring 46 and the amount of eccentricity of the cam ring 45 with respect to the rotor 42 increases, the amount of hydraulic oil discharged also increases accordingly. On the other hand, when the cam ring 45 is moved concentrically by the gallery hydraulic pressure supplied to the hydraulic chamber 48 and the amount of eccentricity of the cam ring 45 with respect to the rotor 42 decreases, the amount of hydraulic oil discharged also decreases accordingly, and the amount of eccentricity of the cam ring 45 further decreases. Becomes substantially zero (a position concentric with the rotor 42), the amount of hydraulic oil discharged is also substantially zero.

  Next, operation | movement of the variable valve apparatus 1 which concerns on this embodiment is demonstrated.

  When connecting the first rocker arm 14A and the second rocker arm 14B, the eccentric amount of the cam ring 45 is increased, and the ON / OFF switching valve 30 is turned on. That is, by opening the ON / OFF switching valve 30 while increasing the hydraulic oil discharge amount of the variable displacement vane pump 40, the hydraulic oil stored in the oil pan 60 is changed from the oil introduction pipe 61 to the variable displacement vane pump. 40 → first oil supply pipe 50 → ON / OFF switching valve 30 → second oil supply pipe 51 → first oil path 13A → second oil path 13B and flows to the oil chamber 22 in this order. Then, the connecting pin 20 moves against the urging force of the spring 24 by the hydraulic pressure of the oil chamber 22 and engages with the pin receiving hole 25, so that the first rocker arm 14A and the second rocker arm 14B are mutually connected. It becomes connected.

  On the other hand, when releasing the connection between the first rocker arm 14A and the second rocker arm 14B, as shown in FIG. 2, the eccentric amount of the cam ring 45 is made substantially zero and the ON / OFF switching valve 30 is turned off. To do. That is, the hydraulic oil discharge amount of the variable displacement vane pump 40 is reduced and the ON / OFF switching valve 30 is closed to cut off the supply of hydraulic oil from the first oil supply pipe 50 to the second oil supply pipe 51. Is done. When the supply of hydraulic oil is cut off in this way, the hydraulic pressure in the oil chamber 22 decreases, the connecting pin 20 is pushed back by the urging force of the spring 24 and is received in the pin receiving hole 21, and the first rocker arm The connection between 14A and the second rocker arm 14B is released.

  As described above in detail, in the variable valve operating apparatus 1 of the present embodiment, when the connection between the first rocker arm 14A and the second rocker arm 14B is released, the ON / OFF switching valve 30 is turned off to open / close the valve. The eccentric amount of the cam ring 45 of the variable displacement vane pump 40 is reduced while shutting off the supply of hydraulic oil to the mechanism 10. That is, at the time of releasing the connection of the rocker arm that eliminates the need for supplying hydraulic oil to the valve opening / closing mechanism 10, the ON / OFF switching valve 30 is closed and the discharge amount of hydraulic oil from the variable displacement vane pump 40 is reduced. Thus, wasteful drainage as in the conventional apparatus is stopped. As a result, the load on the engine is effectively reduced compared to the conventional device that drives the hydraulic oil pump with the same amount of work when the rocker arm is disconnected, and the fuel consumption performance is reliably improved. It becomes possible.

  In addition, this invention is not limited to the above-mentioned embodiment, In the range which does not deviate from the meaning of this invention, it can change suitably and can implement.

  For example, the rocker arms 14A and B have been described as being connected when the hydraulic pressure is high and disconnected when the hydraulic pressure is low, but the rocker arms 14A and B can be reduced by changing the arrangement relationship between the oil chamber 22 and the spring 24. You may comprise so that it may be connected at the time of oil_pressure | hydraulic and may be disconnected at the time of high oil pressure.

  Further, the valve opening / closing mechanism 10 is not limited to the cam switching type, and can be widely applied to other variable valve mechanisms that change the valve opening / closing characteristics by the hydraulic pressure, such as a cam phase variable type.

  Further, it is possible to use a variable displacement pump other than the variable displacement vane pump.

DESCRIPTION OF SYMBOLS 10 Valve opening / closing mechanism 11 Exhaust cam shaft 12A 1st cam 12B 2nd cam 13 Exhaust rocker shaft 14A 1st rocker arm 14B 2nd rocker arm 20 Connecting pin 21 Pin accommodation hole 22 Oil chamber 24 Spring 25 Pin receiving hole 26 Air vent hole 30 ON / OFF switching valve 31 Valve body 31A Suction port 31B Discharge port 32 Piston 33 Return spring 34 Solenoid part 34A Electromagnetic coil 40 Variable displacement vane pump 41 Pump housing 41A Suction port 41B Discharge port 42 Rotor 43 Vane 45 Cam ring 46 Spring 47 Piston 48 Hydraulic chamber 50 First oil supply pipe 51 Second oil supply pipe 52 Bypass flow pipe 53 Orifice 60 Oil pan 61 Oil introduction pipe

Claims (3)

A valve opening / closing mechanism for changing an opening / closing characteristic of at least one of an intake valve or an exhaust valve of the engine by a hydraulic pressure of the supplied hydraulic oil, and a first state in which supply of the hydraulic oil to the valve opening / closing mechanism is allowed; A switching valve that can be selectively switched to a second state that shuts off the supply of hydraulic oil to the mechanism, and a discharge amount of hydraulic oil that is driven by the engine power and is supplied to the valve opening / closing mechanism in the first state. And a variable displacement pump that increases and decreases the discharge amount of hydraulic oil supplied to the valve opening / closing mechanism in the second state. The variable displacement pump is a variable displacement vane pump in which a cam ring is provided on an outer peripheral side of a rotor having a plurality of vanes that can advance and retreat in a radial direction so as to be able to swing eccentrically. The variable valve operating apparatus according to claim 2, wherein an eccentric amount of the cam ring is increased, and an eccentric amount of the cam ring with respect to the rotor is decreased in the second state. A first oil supply channel for connecting the variable displacement pump and the switching valve to supply hydraulic oil from the variable displacement pump to the switching valve; and a connection between the switching valve and the valve opening / closing mechanism. A second oil supply flow path for supplying hydraulic oil from the switching valve to the valve opening / closing mechanism, a connection between the first oil supply flow path and the second oil supply flow path bypassing the switching valve; The variable valve operating apparatus according to claim 1, further comprising a bypass flow path provided with an orifice for restricting the flow path at the predetermined location.

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