JP5342314B2 - Fuel pump drive unit - Google Patents

Description

  The present invention relates to a fuel pump drive device, and more particularly to a fuel pump drive device that supplies fuel to a fuel injection nozzle of a fuel injection type engine.

  Conventionally, a cam sprocket fixed to the end of the camshaft and a crank sprocket fixed to the end of the crankshaft are connected via a timing belt, and a fuel pump that supplies fuel to the fuel injection valve is rotated by the camshaft. A drive device for a fuel pump that is driven is known (see Patent Document 1 below).

JP 2000-8987 A

  By the way, in what is disclosed in Patent Document 1, the rotation shaft of the fuel pump is fixed to the cam sprocket fixed to the camshaft, and the rotation speed of the fuel pump is set to the reduction ratio between the crankshaft and the cam sprocket. Therefore, there is a problem that the degree of freedom in setting the rotational speed of the fuel pump is limited.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a novel fuel pump drive device that can solve the above problems by increasing the degree of freedom in setting the rotational speed of the fuel pump. To do.

In order to achieve the above object, a first aspect of the present invention is a fuel pump drive apparatus in which a valve camshaft is driven by a crankshaft and a fuel pump is driven.
A support bolt fixed to the engine body,
A drive shaft rotatably supported by the journal portion of the support bolt;
The drive shaft is provided with a pump drive transmission wheel fixed by press-fitting, laser welding, or sintered diffusion bonding ,
The support bolt is fastened to the engine body via a washer, and the washer is formed with an oil groove formed in an annular shape in the circumferential direction, and the journal portion is formed with an oil passage communicating with the oil groove. The lubricating oil from the engine body is supplied to the bearing portion of the drive shaft through the oil groove and the oil passage,
The front SL drive shaft, a cam drive gear for driving the valve operating cam shaft, and the pump drive joint for driving a fuel pump is provided,
Before SL pump drive transmission wheel is characterized in that it is connected to a crank driving wheel interlocked with the crankshaft via an endless timing drive belt.

In order to achieve the above object, the invention according to claim 2 is the invention according to claim 1, wherein the pump drive transmission wheel and the cam driven gear for driving the valve camshaft engaged with the cam drive gear include: A jig insertion hole is formed as each phasing means .

According to the present invention, the drive shaft driven timed via a transmission belt contact and pump drive transmission wheel by a crank shaft to drive a cam drive gear for driving the valve operating cam shaft, the fuel pump Since the pump drive joint is provided, it is possible to set the gear ratio between the cam drive gear and the cam driven gear and the gear ratio between the crankshaft and the pump drive transmission wheel. The degree of freedom in setting the rotational speed of the fuel pump can be greatly increased, and the versatility of the fuel pump is enhanced. As a result, the same fuel pump can be applied to various engines having different displacements and the like, which can contribute to the cost reduction of the engine.

In addition , since the pump drive transmission wheel is fixed to the drive shaft by press-fitting, laser welding or sintered diffusion bonding, a fastening member for fastening them is unnecessary, and the pump drive transmission wheel is compact in the radial direction and the number of parts is reduced. Reduction is possible.

Furthermore, since the journal portion for supporting the drive shaft to the supporting bolt is formed integrally, and simplify the structure and reduce the number of components, downsizing in the radial direction of the supporting bolt is figure and the journal portion of the support bolt The bearing portion with the drive shaft can be effectively lubricated by lubrication from the engine body to reduce wear, seizure, and sliding resistance.

Furthermore, since the oil groove formed in the washer is formed in an annular shape in the circumferential direction, it is not necessary to position the washer, and the number of assembling steps and the number of parts can be reduced. Further, by providing the oil groove on the washer side , the oil groove can be formed without increasing the cost by the forging method. (If the oil groove is provided on the engine body side, processing by a tool is required, which increases the cost. ).

According to the second aspect of the present invention, the pump drive transmission wheel and the cam drive gear are each provided with a positioning hole for inserting a jig as a phasing means for the pump drive transmission wheel and the cam drive gear. Can be planned.

1 is a partial front view of a V-type engine equipped with a fuel pump drive device of the present invention. Enlarged cross-sectional view along line 2-2 in FIG. Enlarged view of the phantom line encircled portion in FIG. Sectional view along line 4-4 in FIG. Perspective view of drive part of valve camshaft A perspective view of the drive shaft showing the lubrication path of the drive shaft FIG. 7 is an exploded perspective view of a fuel pump mounting portion as viewed in the direction of arrow 7 in FIG.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on examples of the present invention shown in the accompanying drawings.

  This embodiment is a case where the fuel pump driving device of the present invention is implemented in a V-type engine. In FIG. 1, the V-type engine E is arranged to face each other across the V space V. The left and right banks BL and BR are provided. The left and right banks BL and BR are provided with left and right cylinder blocks 1 and 1 formed in a V shape, and cylinder heads 2 and 2 respectively joined to the inclined deck surfaces, and a head cover 3 on the cylinder heads 2 and 2. , 3 are applied. A crankcase 4 is connected to the lower part of the left and right cylinder blocks 1, 1, and a crankshaft 5 is rotatably mounted on the crankcase 4.

  As shown in FIG. 2, a chain cover 6 is fixed to the engine main body, that is, the front end surfaces of the cylinder head 2 and the head cover 3 by a plurality of bolts 7, and the chain cover 6 and the front end surfaces of the cylinder head 2 and the head cover 3 A sealed transmission chamber C is formed between them.

  On the left and right cylinder heads 2 and 2, intake side and exhaust side valve camshafts 8 and 9 are rotatably supported, respectively. The intake and exhaust side valve camshafts 8 and 9 and the crankshaft 5 of the left and right banks BL and BR are linked to each other via the timing transmission mechanisms TL and TR, respectively. The shaft 5 is rotationally driven at a reduction ratio of 1/2.

In this embodiment, the right bank BR is provided with a fuel pump FP that supplies high-pressure fuel to a fuel injection valve (not shown) that supplies fuel to each combustion chamber of the engine E, and this fuel pump FP. is configured to drive through timing Den kinematic mechanism TR of the right bank BR, below, the structure of the driving device of the fuel pump FP, in FIG. 1, reference also to Fig. 2-7 Will be described in detail.

  In the transmission chamber C, a crank sprocket 10 as a crank transmission wheel is pivotally supported below the right bank BR. The crank sprocket 10 is driven by the crankshaft 5 via a drive gear 13 and a driven gear 14. . A timing transmission chain 11 as an endless timing transmission band suspended around the crank sprocket 10 extends upward in the transmission chamber C and suspends around a pump drive sprocket 12 as a pump drive transmission wheel described later. The pump drive sprocket 12 is rotationally driven by the crankshaft 5.

  As shown in FIGS. 2 and 3, a support bolt 20 is fixed to the front end portion of the cylinder head 2. The support bolt 20 extends in front of the front end portion of the cylinder head 2 in parallel with the valve camshafts 8 and 9, and the screw portion 20s, the journal portion 20j, and the head portion 20h are directed from the inner end toward the outer end. The screw portion 20s is screwed and fastened to the front end portion of the cylinder head 2 via a washer 21. A hollow cylindrical drive shaft 24 is disposed concentrically with the outer side of the support bolt 20, and a boss portion 24 b of the drive shaft 24 is connected to the journal portion 20 j of the support bolt 20 via a surface bearing 25. It is supported rotatably. A cam drive gear 26 is integrally provided at the inner end of the drive shaft 24, and the cam drive gear 26 is meshed with an intake side cam driven gear 27 fixed to the end of the intake side valve camshaft 8. The intake side cam driven gear 27 is meshed with an exhaust side cam driven gear 28 having the same diameter as that fixed to the end of the exhaust side valve cam shaft 9 (see FIG. 5).

The pump drive sprocket 12 is fixed to the outer peripheral surface of the boss portion 24b of the drive shaft 24 by press-fitting. Further, one Oldham joint hub 24 h of the Oldham joint 30 is integrally provided at the outer end of the drive shaft 24.

As shown in FIG. 2, the pump holder 33 is fixed to the engine main body, that is, the front end surfaces of the cylinder head 2 and the head cover 3 by a plurality of bolts 34 across the front end surfaces. The inner surface of the pump holder 33 faces the transmission chamber C, the outer surface faces the outside through the opening 36 of the chain cover 6, and the pump holder 33 has an endless shape on the outer circumferential surface . The chain cover 6 is brought into contact with the packing 35 and the space between the pump holder 33 and the chain cover 6 is sealed. As shown in FIGS. 2 and 7, a cylindrical pump insertion hole 37 that connects the transmission chamber C and the outside is formed at the center of the pump holder 33. A plurality of pump mounting bosses 38 are formed around the pump insertion hole 37, and the fuel pump FP is fixed to the pump mounting bosses 38 with bolts 39. The pump shaft 40 of the fuel pump FP is inserted into the pump insertion hole 37, and the other Oldham joint hub 40h at the end of the pump shaft 40 is inserted into one of the outer ends of the drive shaft 24 via the insert 41. Accordingly, the pump shaft 40 of the fuel pump FP is detachably connected to the drive shaft 24 via the Oldham joint 30, and a parallel error between the pump shaft 40 and the drive shaft 24 is reduced. The fuel pump FP can be driven by the drive shaft 24 after absorption.

  Lubricating oil is supplied to the journal portion 20j of the support bolt 20 and the bearing portion of the drive shaft 24 rotatably supported by the journal portion 20j via the surface bearing 25 there. As shown in FIGS. 2, 3, and 6, an annular oil groove 45 is formed on the side surface of the washer 21 that faces the end surface of the cylinder head 2, while the journal portion 20 j of the support bolt 20 An oil passage 46 communicating with the oil groove 45 is formed in the axial direction, the oil passage 46 is communicated with an oil groove 47 formed on the inner peripheral surface of the surface bearing 25, and the annular oil groove 45 is connected to the cylinder head 2. It communicates with the formed oil supply passage 48. Accordingly, the lubricating oil from the oil supply passage 48 of the cylinder head 2 is forcibly supplied to the relative rotating portion between the support bolt 20 and the drive shaft 24 through the oil groove 45, the oil passage 46, and the oil groove 47, and the drive shaft 24 is smoothly supplied. Rotation is guaranteed.

  As shown in FIG. 3, insertion holes 50 and 51 of jigs that coincide with each other in the rotation direction are formed in the pump drive sprocket 12 and the cam driven gear 27, and jigs are inserted into the insertion holes 50 and 51. By inserting J, their relative positioning is made.

As shown in FIG. 1, the intake side and exhaust side valve camshafts 8 and 9 of the left bank BL are driven by the crankshaft 5 via a normal timing transmission mechanism TL. The crank sprocket 55 that is pivotally supported at the lower portion of the left bank is driven by the crankshaft 5 via the drive gear 13 and the driven gear 54. The endless timing transmission chain 56 that is suspended by the crank sprocket 55 is suspended by a camshaft drive sprocket 57 that is pivotally supported by the cylinder head 2 of the left bank BL. The camshaft is linked to intake and exhaust side valve camshafts 8 and 9 via cam gears.

  In FIG. 1, 58 and 59 are guides for guiding the tension side of the endless transmission chains 11 and 56, 60 and 61 are guides for guiding the loose side of the endless transmission chains 11 and 56, 62, A tensioner 63 adjusts the tension of the endless transmission chains 11 and 56.

  Next, the operation of this embodiment will be described.

When the crankshaft 5 is rotationally driven by the operation of the engine E, the drive shaft 24 is rotationally driven via the crank sprocket 10, the timing transmission chain 11, and the pump drive sprocket 12. As a result, the cam drive gear 26 integral with the drive shaft 24 is driven , and the valve drive cam shafts 8 and 9 are driven via the intake side cam driven gear 27 and the exhaust side cam driven gear 28 meshed therewith. . Further, the fuel pump FP is driven through the Oldham joint 30 by the drive shaft 24 integrated with the pump drive sprocket 12, and high pressure fuel is supplied to a fuel injection valve (not shown).

  At this time, the gear ratio between the cam drive gear 26 and the cam driven gear 27 and the gear ratio between the crankshaft 5 and the pump drive sprocket 12 can be set. Therefore, the combination of these gear ratios enables the fuel pump FP. The degree of freedom in setting the speed ratio of the rotation speed is increased.

The pump drive sprocket 12, because it is fixed by press fitting to the drive shaft 24, the fastening member is not required to enter into them, radially compact pump drive sprocket 12, both the number of components is reduced can be achieved.

  The fixing means for fixing the pump drive sprocket 12 to the drive shaft 24 may be laser welding or sintered diffusion bonding in addition to press-fitting.

  Furthermore, since the journal portion 20j that supports the drive shaft 24 is integrally formed with the support bolt 20, the number of parts can be reduced, the structure can be simplified, and the support bolt 20 can be made compact in the radial direction. The bearing portion between the journal portion 20j of the support bolt 20 and the drive shaft 24 can be effectively lubricated by lubrication from the engine body, that is, the cylinder head 2 to reduce wear, seizure, and sliding resistance.

  Furthermore, since the oil groove 45 formed in the washer 21 is formed in an annular shape in the circumferential direction, positioning of the washer 21 is not necessary, and the number of assembling steps and the number of parts can be reduced.

  Furthermore, since the pump drive sprocket 12 and the cam driven gear 27 are respectively provided with jig insertion holes 50 and 51 as phasing means, the number of assembling steps of the pump drive device can be reduced.

  As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

  For example, in the above-described embodiment, the case where the present invention is applied to a V-type engine has been described, but it is needless to say that this can be applied to other engines. In the above embodiment, the crank transmission sprocket, the timing transmission chain, and the pump drive sprocket are used as the crank transmission wheel, the timing transmission band, and the pump drive transmission wheel. Synchronous materials such as a time transmission belt and a pump drive sheave may be used.

2 ... Engine body (cylinder head)
5 ... Crankshaft 10 ... Crank transmission wheel (crank sprocket)
11 ・ ・ ・ ・ ・ ・ ・ ・ Timed transmission band (Timed transmission chain)
12 ... Pump-driven transmission wheel (pump-driven sprocket)
20 ············ Support bolt 20j ········· Journal portion 24 ······ Drive shaft 24h ·········· Pump drive joint (Oldham joint hub)
26... Cam drive gear 27... Cam driven gear 50... Jig insertion hole 51. FP ・ ・ ・ ・ ・ ・ ・ ・ Fuel pump

Claims (2)

A fuel pump drive device configured to drive a valve camshaft (8, 9) and a fuel pump (FP) by a crankshaft (5),
A support bolt (20) fixed to the engine body (2);
A drive shaft (24) rotatably supported on a journal portion (20j) of the support bolt (20);
A pump drive transmission wheel (12) fixed to the drive shaft (24) by press-fitting, laser welding, or sintered diffusion bonding ,
The support bolt (20) is fastened to the engine body (2) via a washer (21), and the washer (21) is formed with an oil groove (45) formed in an annular shape in the circumferential direction, An oil passage (46) communicating with the oil groove (45) is formed in the journal portion (20j), and lubricating oil from the engine body (2) passes through the oil groove (45) and the oil passage (46). Oil is supplied to the bearing portion of the drive shaft (24),
The front SL drive shaft (24), the valve operating cam shaft and cam drive gear (26) to drive the (8,9), the pump drive joint for driving a fuel pump (FP) (24h) and is provided,
Before SL pump drive transmission wheel (12) is characterized in that it is connected to a crank driving wheel interlocked with the crankshaft (5) via an endless timing drive belt (11) (10), fuel Pump drive device. The pump drive transmission wheel (12) and the valve drive cam shaft (8, 9) drive cam driven gear (27) meshed with the cam drive gear (26) are inserted with jigs as phase determining means thereof. 2. The fuel pump drive device according to claim 1 , wherein the holes (50, 51) are formed, respectively .

Images