JP2009275592A - Drive device for vacuum pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive device for a vacuum pump capable of suppressing deterioration of fuel consumption of an internal combustion engine by preventing needless driving of the vacuum pump. <P>SOLUTION: The drive device 26 is equipped with a clutch mechanism 28 disposed between a camshaft 16 of the internal combustion engine and a drive shaft 27 of the vacuum pump capable of connecting and disconnecting power transmission. The clutch mechanism 28 includes: a plunger 31 capable of integrally and rotatably restraining the camshaft 16 and the drive shaft 27 by being interposed between the cam shaft 16 and the drive shaft 27, and moving between a restraining position for restraining the cam shaft 16 and the drive shaft 27, and a releasing position for releasing the restraint; and a moving mechanism 32 for moving the plunger 31 from the restraining position to the releasing position by using negative pressure of a suction pipe of the internal combustion engine when the negative pressure of the suction pipe exceeds a predetermined level. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive device for a vacuum pump provided to make up for a shortage of intake pipe negative pressure in an internal combustion engine.

  In order to stably introduce a negative pressure into each part of an internal combustion engine or a vehicle equipped with the internal combustion engine, a vacuum pump that compensates for a shortage of the intake pipe negative pressure of the internal combustion engine may be provided. In general, such a vacuum pump is driven using power extracted from a crankshaft or a camshaft of an internal combustion engine. As a driving device for such a vacuum pump, a vacuum pump is connected to a housing member of a valve opening / closing timing control device attached to one end of a camshaft via a joint member (Patent Document 1). Known are one that is connected to one end of a camshaft via a clutch element (Patent Document 2) and one that drives a vacuum pump by an intermediate shaft arranged in a power transmission path from the crankshaft to the camshaft (Patent Document 3). It has been.

JP 2005-76482 A JP-T-2006-511749 JP 2002-235549 A

  In the driving devices described in these documents, there is a possibility that the vacuum pump is driven even when the intake pipe negative pressure of the internal combustion engine is sufficient and the assistance of the vacuum pump is not required. Therefore, there is a possibility that the friction loss of the internal combustion engine increases due to useless driving of the vacuum pump, and the fuel consumption deteriorates.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum pump drive device that can prevent wasteful drive of a vacuum pump and suppress deterioration in fuel consumption of an internal combustion engine.

  The vacuum pump drive device according to the present invention is a vacuum pump drive device for driving a vacuum pump provided to compensate for a shortage of intake pipe negative pressure of the internal combustion engine by using the power of the internal combustion engine. A rotating member that transmits power of the motor, and a clutch mechanism that is interposed between the rotating member and the drive shaft of the vacuum pump and that can intermittently transmit power from the rotating member to the drive shaft. The mechanism is interposed between the rotating member and the drive shaft so that the rotating member and the drive shaft can be constrained so as to be integrally rotatable, and a restraining position for restraining the rotating member and the driving shaft is constrained. A restraint member that can move between a release position for releasing the intake pipe and the restraint member using the intake pipe negative pressure when the intake pipe negative pressure of the internal combustion engine exceeds a predetermined level. By providing a moving means for moving to the release position from solves the problems described above (claim 1).

  According to this drive device, when the intake pipe negative pressure of the internal combustion engine exceeds a predetermined level, the restraint member can be moved to the release position by using the intake pipe negative pressure. When the restraining member moves to the release position, the restraint between the rotating member and the drive shaft is released, so that power transmission from the rotating member to the vacuum pump is interrupted. Therefore, by setting the predetermined level so that the restraining member moves to the release position when the intake pipe negative pressure of the internal combustion engine is sufficient, the intake pipe negative pressure of the internal combustion engine is sufficient and does not require the assistance of the vacuum pump. Sometimes it is possible to prevent the vacuum pump from being wasted. As a result, friction loss due to wasteful driving of the vacuum pump does not occur, and deterioration of fuel consumption of the internal combustion engine can be suppressed.

  In one aspect of the driving apparatus of the present invention, the moving means includes a biasing member that biases the restraining member toward the restraining position, and introduces intake pipe negative pressure to move the restraining member to the release position. And a negative pressure mechanism that moves to the side against the urging force of the urging member (claim 2). According to this aspect, when the intake pipe negative pressure is not introduced into the negative pressure mechanism, the restraining member is biased toward the restraining position by the biasing member, so that the restraining member can be easily brought into the restraining position without requiring external energy. Can be retained.

  The negative pressure mechanism may have any configuration. For example, the rotating member and the drive shaft are arranged coaxially with their end faces facing each other, and the restraining member is axially disposed on the drive shaft. A second insertion hole in which the first insertion hole is slidably inserted into the rotary member and is positioned on an extension of the first insertion hole, and the restraining member is slidably inserted in the axial direction And the negative pressure chamber formed by being surrounded by the drive shaft and the restraining member when the restraining member is inserted into the first insertion hole, An introduction passage for introducing intake pipe negative pressure into the negative pressure chamber may be provided, and the urging member may be disposed in the negative pressure chamber. In this case, the negative pressure mechanism effectively uses the insertion holes formed in the rotating member and the drive shaft, and the biasing member is disposed in the negative pressure chamber provided as the negative pressure mechanism. Compared to the case where the pressure mechanism is provided independently of the rotating member and the drive shaft, the space efficiency is good. Therefore, it is easy to reduce the size of the device, and it is easy to form an empty space around the clutch mechanism.

  As described above, according to the present invention, when the intake pipe negative pressure of the internal combustion engine exceeds a predetermined level, the restraint member can be moved to the release position by using the intake pipe negative pressure. When the restraining member moves to the release position, the restraint between the rotating member and the drive shaft is released, so that power transmission from the rotating member to the vacuum pump is interrupted. Therefore, by setting the predetermined level so that the restraining member moves to the release position when the intake pipe negative pressure of the internal combustion engine is sufficient, the intake pipe negative pressure of the internal combustion engine is sufficient and does not require the assistance of the vacuum pump. Sometimes it is possible to prevent the vacuum pump from being wasted. As a result, friction loss due to wasteful driving of the vacuum pump does not occur, and deterioration of fuel consumption of the internal combustion engine can be suppressed.

  FIG. 1 schematically shows a main part of an internal combustion engine to which a vacuum pump to which a drive device according to an embodiment of the present invention is applied is attached. The internal combustion engine 1 is mounted on a vehicle as a driving power source. The internal combustion engine 1 is configured as an in-line four-cylinder spark ignition type internal combustion engine in which four (one in the figure) cylinders 2 are arranged in one direction in a cylinder block. A piston 3 is inserted in each cylinder 2 so as to be reciprocally movable, and an opening of each cylinder 2 is closed by a cylinder head 4. The reciprocating motion of the piston 3 is transmitted to the crankshaft 5 via a connecting rod (not shown). The internal combustion engine 1 is provided with an intake passage 6 for guiding air to each cylinder 2. Exhaust gas from each cylinder 2 is discharged from an exhaust passage (not shown). The intake passage 6 is provided with an air filter 7 for air filtration and a throttle valve 8 for adjusting the intake air amount.

  The intake passage 6 includes a surge tank 9 having a predetermined volume and a branch passage 10 that branches from the surge tank 9 to each cylinder 2. Each branch passage 10 further branches into intake ports 11 that are provided in two for each cylinder 2. The intake port 11 is formed in the cylinder head 4, and an end thereof opens to the cylinder 2. Each intake port 11 is opened and closed by an intake valve 12. Each intake valve 12 is driven to open and close by a valve mechanism 13. The valve mechanism 13 includes a cam mechanism 14 that linearly moves each intake valve 12 via a rocker arm (not shown), and a power transmission mechanism 15 that transmits the power of the crankshaft 5 to the cam mechanism 14.

  The cam mechanism 14 includes a cam shaft 16 that is rotationally driven by the power transmission mechanism 15, and cams 17 that are formed on the cam shaft 16 and provided one by one with respect to the intake valve 12. The power transmission mechanism 15 includes a driving pulley 18 that rotates integrally with the crankshaft 5, a driven pulley 19 provided at an end 16 a of the camshaft 16, and a timing belt 20 that is wound around these pulleys 18 and 19. Have. The speed ratio of these pulleys 18 and 19 is set to 2: 1, and the camshaft 16 rotates once while the crankshaft 5 rotates twice.

  The valve mechanism 13 further includes a well-known valve timing control device 21 interposed between the driven pulley 19 and the camshaft 16 in order to change the correspondence of the rotational position between the crankshaft 5 and the camshaft 16. I have. The valve timing control device 21 is operated using a hydraulic pressure generated by an oil pump (not shown), and can shift the rotational position of the cam shaft 16 to the retard side or the advance side. The control of the valve timing by the control device 21 is appropriately executed according to the operating state of the internal combustion engine 1. For example, when the internal combustion engine 1 has not been warmed up, the valve timing control device 21 is controlled so that the valve timing is retarded in order to accelerate the warm-up completion.

  When the valve timing of the intake valve 12 is changed to the retard side, the intake valve negative pressure formed in the intake passage 6 becomes smaller because the valve opening period of the intake valve is delayed than before the change. There is a risk of insufficient pressure. If the intake pipe negative pressure is insufficient, for example, the negative pressure leading to the brake booster 22 of the vehicle is insufficient, resulting in an increase in brake pedal force. Therefore, the internal combustion engine 1 is provided with a vacuum pump 25 that generates a negative pressure in order to compensate for the shortage of the intake pipe negative pressure. Since the vacuum pump 25 has a well-known configuration, a detailed description of the internal structure is omitted.

  The vacuum pump 25 is driven by a drive device 26, and the drive device 26 drives the vacuum pump 25 using the power of the internal combustion engine 1, here, the power of the cam shaft 16. The drive device 26 is a clutch that is interposed between the drive shaft 27 of the vacuum pump 25 and the cam shaft 16 as a rotating member that protrudes outward from the head cover 23 and can intermittently transmit power from the cam shaft 16 to the drive shaft 27. A mechanism 28 is provided. The cam shaft 16 and the drive shaft 27 are coaxially arranged with their end faces facing each other. An oil seal 24 is attached between the head cover 23 and the cam shaft 16, and the end 16 b of the cam shaft 16 is sealed by the oil seal 24. The vacuum pump 25 and the surge tank 9, which are the sources of negative pressure, are connected to the brake booster 22 via a negative pressure pipe 29. The clutch mechanism 28 is configured to operate using intake pipe negative pressure, and intake pipe negative pressure is introduced into the clutch mechanism 28 via an introduction pipe 30 branched from the negative pressure pipe 29. Yes. In addition, when a supercharger is mounted on the internal combustion engine 1, an operating region in which the inside of the surge tank 9 becomes positive pressure is generated, but the positive pressure is prevented from being guided to the clutch mechanism 28 in such an operating region. A check valve 31 is provided on the introduction pipe 30.

  FIG. 2 is an explanatory diagram for explaining a main part of the driving device 26 provided with the clutch mechanism 28. The clutch mechanism 28 includes a plunger 31 as a restraining member interposed between the cam shaft 16 and the drive shaft 27 of the vacuum pump 25, and a moving mechanism 32 as moving means for moving the plunger 31 using intake pipe negative pressure. And. The cam shaft 16 and the drive shaft 27 are coaxially arranged with their end faces facing each other, and the drive shaft 27 has a first insertion hole 33 into which the plunger 31 is slidably inserted. Are formed with second insertion holes 34 into which the plungers 31 are slidably inserted. Each insertion hole 33, 34 extends in the direction of the axis Ax of the cam shaft 16, and the second insertion hole 34 is located on the extension of the first insertion hole 33.

  The clutch mechanism 28 functions as a detent means for preventing relative rotation between the plunger 31, the cam shaft 16 and the drive shaft 27 when the plunger 31 is inserted into each of the first insertion hole 33 and the second insertion hole 34. Serration 35 is provided. The serrations 35 are respectively formed on the outer peripheral surface of the plunger 31 and the inner peripheral surfaces of the insertion holes 33 and 34. It should be noted that a square spline or the like can be employed instead of the serration 35 as such a detent means.

  Since each insertion hole 33, 34 is coaxial and the second insertion hole 34 is located on the extension of the first insertion hole 33, the plunger 31 inserted into these insertion holes 33, 34 is inserted into the first insertion hole 33, 34. It is possible to move while straddling the boundary between the hole 33 and the second insertion hole 34. The position of the plunger 31 indicated by a solid line in FIG. 2 is a release position where power transmission is interrupted, and the position of the plunger 31 indicated by an imaginary line is a restraint position. In the restrained position, a part of the plunger 31 in the longitudinal direction is inserted into the first insertion hole 33 and the remaining part is inserted into the second insertion hole 34. In other words, in the restrained position, the plunger 31 is in a state of straddling the boundary between the first insertion hole 33 and the second insertion hole 34. Therefore, the plunger 31 located at the restraining position can restrain the cam shaft 16 and the drive shaft 27 so as to be integrally rotatable.

  The moving mechanism 32 introduces a spring 36 as an urging member that urges the plunger 31 toward the restraint position (left side in FIG. 2) and the intake pipe negative pressure, thereby moving the plunger 31 toward the release position (in FIG. 2). And a negative pressure mechanism 37 that moves to the right) against the urging force of the spring 36. The spring 36 is configured as a coil spring, but may be a spring of another form. Further, instead of the spring 36, an elastic body such as rubber may be provided as a biasing member.

  The negative pressure mechanism 37 includes a negative pressure chamber 38 formed by being surrounded by the drive shaft 27 and the plunger 35 when the plunger 35 is inserted into the first insertion hole 33, and an intake pipe in the negative pressure chamber 38. An introduction passage 39 for introducing a negative pressure is provided. The aforementioned spring 36 is disposed in a compressed state in the negative pressure chamber 38. The introduction passage 39 has one end opened to the negative pressure chamber 38 and the other end connected to the introduction pipe 30 (see also FIG. 1). As a result, intake pipe negative pressure is introduced into the negative pressure chamber 38 via the introduction passage 39 and the introduction pipe 30. In order to facilitate the movement of the plunger 35 in a state where the plunger 35 is inserted into the first insertion hole 33, the cam shaft 16 communicates with the first insertion hole 33 and the outer peripheral surface of the end portion 16 b exposed from the head cover 23. A communication hole 40 is provided in the opening.

  When the force pulling the plunger 35 by the intake pipe negative pressure introduced into the negative pressure chamber 38 is equal to or less than the biasing force (elastic force) of the spring 36, the plunger 35 is held at the restrained position by the elastic force. Thereby, power transmission from the cam shaft 16 to the drive shaft 27 is ensured by the clutch mechanism 28. Since the movement and holding to the restraining position are covered by the elastic energy stored in the spring 36, no external energy is required to do this. On the other hand, when the force pulling the plunger 35 is larger than the elastic force of the spring 36, the plunger 35 is pulled toward the release position against the elastic force and held in the release position. As a result, power transmission from the cam shaft 16 to the drive shaft 27 is interrupted by the clutch mechanism 28.

  Conditions under which the clutch mechanism 28 interrupts power transmission can be adjusted by appropriately changing specifications such as the spring constant and natural length of the spring 36. In the case of this embodiment, when the suction pipe negative pressure is insufficient and the vacuum pump 25 should be driven, the plunger 35 is in the restraining position, and the suction pipe negative pressure exceeds a predetermined level, and the vacuum pump 25 does not need assistance. The specifications of the spring 36 are set so that the plunger 35 is positioned at the release position at any time. As a result, it is possible to prevent the vacuum pump 25 from being driven wastefully when the intake pipe negative pressure of the internal combustion engine 1 is sufficient and the vacuum pump 25 does not require assistance. Therefore, friction loss due to wasteful driving of the vacuum pump 25 does not occur, so that deterioration in fuel consumption of the internal combustion engine 1 can be suppressed.

  In the clutch mechanism 28, the negative pressure mechanism 37 effectively uses the insertion holes 33 and 34 formed in the cam shaft 16 and the drive shaft 27, and the spring 36 is disposed in the negative pressure chamber 38. As compared with the case where the negative pressure mechanism 37 is provided independently of the cam shaft 16 and the drive shaft 27, the space efficiency is good. Therefore, it is easy to reduce the size of the device, and it is easy to form an empty space around the clutch mechanism 28.

  This invention is not limited to the above form, It can implement with a various form. The configuration of the clutch mechanism is not limited to the form shown in FIG. For example, the drive device according to the present invention can be implemented by changing the clutch mechanism 28 to the mechanism shown in FIG. FIG. 3 shows a main part of a drive apparatus provided with another type of clutch mechanism. With respect to the configuration common to the clutch mechanism 28 of FIG. 2, the same reference numerals are given in FIG. 3 is incorporated in the internal combustion engine 1 as in the case of the drive device 26 of FIG. 2 (see FIG. 1).

  The clutch mechanism 51 in FIG. 3 includes a plunger 52 as a restraining member, and a moving mechanism as a moving means that moves the plunger 52 from an imaginary line restraining position to a solid line releasing position using intake pipe negative pressure. 53. The plunger 52 is configured in a hat shape having a flange 52a formed at the base end. The moving mechanism 53 is integrally formed at the tip of the drive shaft 27. The moving mechanism 53 includes a support portion 54 that extends coaxially with the drive shaft 27 and covers the plunger 52, and a guide wall portion 55 that surrounds the outer periphery of the support portion 54. An annular guide space 56 is formed between the support portion 54 and the guide wall portion 55. The plunger 52 and the support portion 54 are splined via a spline 57. Accordingly, the plunger 52 and the support portion 54 can rotate integrally with each other, and the plunger 52 can move in the direction of the axis Ax with respect to the support portion 54.

  An insertion hole 58 into which the plunger 52 can be inserted is formed at the end of the cam shaft 16, and the insertion hole 58 is located on the extension of the support portion 54 and extends in the direction of the axis Ax. Serrations 59 functioning as detent means on the outer peripheral surface of the plunger 52 and the inner peripheral surface of the insertion hole 58 so that the plunger 52 can rotate integrally when a part of the plunger 52 in the longitudinal direction is inserted into the insertion hole 58. Is formed. Accordingly, when the plunger 52 is positioned at the restraining position inserted into the insertion hole 58 while maintaining the spline coupling with the support portion 54, the plunger 52 restrains the cam shaft 16 and the drive shaft 27 so as to be integrally rotatable. it can. Thereby, power transmission between the camshaft 16 and the drive shaft 27 is allowed. On the other hand, when the plunger 52 moves to the release position side and completely comes out of the insertion hole 58, the power transmission between the cam shaft 16 and the drive shaft 27 is interrupted.

  The moving mechanism 53 introduces a spring 60 as an urging member that urges the plunger 52 toward the restraint position (left side in FIG. 3) and the intake pipe negative pressure, thereby bringing the plunger 52 into the release position (FIG. 3). And a negative pressure mechanism 61 that moves against the urging force of the spring 60. The negative pressure mechanism 61 is provided with a negative pressure chamber 62 provided in the guide space 56 and an introduction passage 63 for introducing intake pipe negative pressure into the negative pressure chamber 62. When the plunger 52 is put on the support portion 54, the guide space 56 is sealed by a seal ring 64 provided in the flange portion 52a, and a negative pressure chamber 62 is formed in the sealed space. A spring 60 is disposed in the negative pressure chamber 62 in a compressed state. The introduction passage 63 has one end opened to the negative pressure chamber 62 and the other end connected to the introduction pipe 30 (see also FIG. 1). As a result, intake pipe negative pressure is introduced into the negative pressure chamber 62 via the introduction passage 63 and the introduction pipe 30. In order to facilitate the movement of the plunger 52 in a state of being inserted into the insertion hole 58, the cam shaft 16 is provided with a communication hole 64 that communicates with the insertion hole 58 and opens on the outer peripheral surface of the end portion 16b exposed from the head cover 23. It has been.

  Conditions for the clutch mechanism 51 to intermittently transmit power between the camshaft 16 and the drive shaft 27 are determined by the specifications of the spring 60, and the specifications are set so that the clutch mechanism 51 can operate in the same manner as the clutch mechanism 28 of FIG. ing. With the above configuration, the clutch mechanism 51 shown in FIG. 3 can function in the same manner as the clutch mechanism 28 of FIG. Therefore, the drive device 50 can also exhibit the same effect as the drive device 26 of FIG.

  In the drive device of the above form, the camshaft of the internal combustion engine is used as the rotating member. However, the rotating member may have any form as long as the power of the internal combustion engine is transmitted. For example, an intermediate shaft disposed in the power transmission path from the crankshaft to the camshaft can be used as the rotating member.

The figure which showed typically the principal part of the internal combustion engine with which the vacuum pump to which the drive device which concerns on one form of this invention was applied was attached. Explanatory drawing explaining the principal part of the drive device of FIG. Explanatory drawing explaining the principal part of the drive device provided with the clutch mechanism of the other form.

Explanation of symbols

1 Internal combustion engine 16 Cam shaft (rotating member)
25 Vacuum pump 26 Drive device 27 Drive shaft 28 Clutch mechanism 31 Plunger (restraint member)
32 Moving mechanism (moving means)
33 First insertion hole 34 Second insertion hole 35 Spring (biasing member)
37 Negative pressure mechanism 38 Negative pressure chamber 39 Introduction passage 50 Drive device 51 Clutch mechanism 52 Plunger (restraint member)
53 Moving mechanism (moving means)
60 Spring (biasing member)
61 Negative pressure mechanism

Claims (3)

In a vacuum pump drive device for driving a vacuum pump provided to compensate for a shortage of intake pipe negative pressure of an internal combustion engine using the power of the internal combustion engine,
A rotating member to which the power of the internal combustion engine is transmitted, and a clutch mechanism that is interposed between the rotating member and the drive shaft of the vacuum pump and capable of intermittently transmitting power from the rotating member to the drive shaft. ,
The clutch mechanism is interposed between the rotating member and the drive shaft so as to restrain the rotating member and the drive shaft so as to be integrally rotatable, and a restraining position for restraining the rotating member and the drive shaft. A restraining member that can move between a release position for releasing the restraint, and when the intake pipe negative pressure of the internal combustion engine exceeds a predetermined level, the intake pipe negative pressure is used to move the restraint member from the restraint position. And a moving means for moving the release position to the release position.   The moving means includes an urging member that urges the restraining member toward the restraining position and an urging force of the urging member toward the release position by introducing an intake pipe negative pressure. The drive device according to claim 1, further comprising a negative pressure mechanism that moves against the negative pressure mechanism. The rotating member and the drive shaft are arranged coaxially with their end faces facing each other,
The drive shaft has a first insertion hole into which the restraining member is slidably inserted in the axial direction, the rotating member is positioned on an extension of the first insertion hole, and the restraining member is in the axial direction. Each of the second insertion holes to be slidably inserted is formed,
The negative pressure mechanism includes a negative pressure chamber formed by being surrounded by the drive shaft and the restricting member when the restricting member is inserted into the first insertion hole, and an intake pipe negative in the negative pressure chamber. An introduction passage for introducing pressure, and
The drive device according to claim 2, wherein the biasing member is disposed in the negative pressure chamber.

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