JP2009185608A - Fuel supply pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply pump having a bearing structure ensuring assemblability with a drive shaft and having excellent seizure resistance and excellent strength, in the fuel supply pump in which the cam of the drive shaft having the cam and a bearing section except for the cam are supported by bearing bushes. <P>SOLUTION: This fuel supply pump includes: a plunger 35 pressurizing and forcibly feeding fuel in a pressurizing chamber 32; the drive shaft 80 integrally formed with the decentered cam 83; an annular cam ring 90 provided on the outer periphery of the cam, revolving with rotation of the drive shaft, and transmitting driving force from the drive shaft to the plunger; and a housing 2 having a cam chamber 21 storing the cam and cam ring, a shaft hole part rotatably supporting the drive shaft, and a cylinder section 31 reciprocatably supporting the plunger and forming the pressurizing chamber. The drive shaft is journalled from the outside by the bearing bushes 51, 52, 92 provided to the cam ring and shaft hole part. The cam ring 90 provided with the bearing bush 92 is divided at a plurality of portions over the peripheral direction of the cam ring. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel supply pump, for example, a fuel supply pump that pumps fuel to a fuel injection pressure in a fuel injection device of a diesel engine.

  Conventionally, a cam that is disposed between a fuel tank and an internal combustion engine, is integrated with a drive shaft inside, rotates eccentrically, and is disposed circumferentially at predetermined angular intervals on the outer peripheral side of the cam, and reciprocally moves. A fuel supply including a plunger that pressurizes fuel and pumps it to an internal combustion engine, a cam ring (shoe) that is disposed between the cam and the plunger and that is in sliding contact with both the cam and the plunger, and a housing that rotatably supports the drive shaft A pump is known (see Patent Document 1).

Bearing bushes are provided at a plurality of support points between the drive shaft and the housing and between the cam and the cam ring of the fuel supply pump having such a configuration. The drive shaft and the cam are respectively supported by the bearing bushes held by the housing and the cam ring. It is supported rotatably from the outside. Between these drive shafts and bearing bushes (hereinafter referred to as drive shaft side bearing bushes) and between the cam and bearing bushes (hereinafter referred to as cam side bearing bushes), a lubricating oil film is formed by lubrication with fuel. This suppresses seizure of the drive shaft and the cam.
JP 2000-240531 A

  In a fuel supply pump having a plunger that reciprocates by rotating a cam and pressurizes and pumps fuel as disclosed in Patent Document 1, the drive shaft and the cam are reciprocated in the radial direction. Each time a radial force is applied from the plunger. In particular, if the fuel is increased to a fuel injection pressure by the pumping operation of the plunger, a high load is applied to the drive shaft and the cam, so seizure is ensured while ensuring strength against the load. May be difficult to suppress.

  In order to improve seizure resistance and strength, it is conceivable to develop a bush material having excellent seizure resistance and strength. However, since seizure resistance and strength are contradictory properties in the development of bush materials, there is a limit to solving the problem of “excellent seizure resistance and strength” by developing bush materials.

  Moreover, in order to improve the said seizure resistance and intensity | strength, it is possible to reduce the surface pressure between a bearing bush and a counterpart member. For example, by increasing the outer diameter of the drive shaft and the inner diameter of the drive shaft-side bearing bush, it is possible to reduce the surface pressure and improve the seizure resistance. However, the drive shaft is integrally formed with a cam that is eccentric with respect to the shaft, and the outer diameter of the drive shaft is set so that the cam shaft can be easily assembled when the cam-side bearing bush is assembled to the cam. The outer diameter of the cam and the amount of eccentricity of the cam are determined. Therefore, if the outer diameter of the drive shaft is increased, the cam-side bearing bush may not be assembled to the cam.

  If the outer diameter of the cam is increased in order to ensure the above assembly, the size of the fuel supply pump will increase, leading to an increase in the cost of the fuel supply pump and the possibility of mounting on an internal combustion engine. is there.

  The present invention has been made in view of such problems, and in the case where the cam of the drive shaft having the cam and the bearing portion other than the cam are supported by the bearing bush, the assembly with the drive shaft is ensured. An object of the present invention is to provide a fuel supply pump having a bearing structure that is excellent in seizure resistance and strength at a bearing portion.

  In order to achieve the above object, the present invention comprises the following technical means.

That is, in the invention described in claims 1 to 11, a plunger that pressurizes and pumps the fuel sucked into the pressurizing chamber, a drive shaft in which the cam is eccentrically formed integrally, and an annular outer periphery of the cam. A cam ring that revolves without rotating with the rotation of the drive shaft and transmits drive force from the drive shaft to the plunger, a cam chamber that houses the cam and the cam ring, and a shaft hole that rotatably supports the drive shaft And a housing having a cylinder portion that forms a pressurizing chamber while supporting the plunger so as to be capable of reciprocating in the radial direction, and the drive shaft is axially supported by a bearing bush provided in the cam ring and the shaft hole portion. In the fuel supply pump
A cam ring provided with a bearing bush is divided at a plurality of locations along the circumferential direction of the cam ring.

  According to such a configuration, the cam ring is divided at a plurality of locations along the circumferential direction. And the bearing bush which supports the cam of a drive shaft from the outside is divided | segmented with a cam ring. Thereby, the divided | segmented bearing bush and cam ring can be assembled | attached to the sliding surface of a cam from radial direction. Therefore, as in the prior art, the cam ring having the bearing bush is inserted from the shaft end portion of the drive shaft, and the cam ring is directed from the shaft center of the drive shaft toward the cam formed integrally with the drive shaft. It is not necessary to attach to the cam while shifting in the direction. For example, when the outer diameter of the portion other than the cam corresponding to the shaft hole in the drive shaft or the outer diameter of the cam is increased, the outer diameter surface of the portion other than the cam of the drive shaft is radially outward from the outer diameter surface of the cam. Since there is no need to insert the bearing bush and the cam ring into the drive shaft, it is possible to prevent the bearing bush and the cam ring from interfering with the drive shaft. In addition, the outer diameter of the drive shaft other than the cam or the outer diameter of the cam can be increased, that is, each bearing bush can be enlarged to reduce the surface pressure. Improves stickiness and strength.

  According to the first aspect of the present invention, the cam of the drive shaft having the cam and the bearing portion other than the cam are supported by the bearing bush. A fuel supply pump having a bearing structure with excellent seizure resistance and strength can be obtained.

  The invention according to any one of claims 2 to 6 is characterized in that the cam ring part divided in the cam ring includes an axial direction restricting part for restricting the mutual movement of the cam ring part in the axial direction.

  In this invention, when the cam ring parts divided in the cam ring provided with the bearing bush are assembled from the radial direction toward the cam, the cam ring parts may be displaced in the axial direction. Since the axial direction restricting part for restricting the axial movement of the cam ring part is provided, it is possible to prevent the cam ring parts from being displaced in the axial direction.

According to a third aspect of the present invention, the axial direction restricting portion is provided on one of the cam ring portions and on the other of the cam ring portions, and the first step portion. With this configuration, the second stepped portion that abuts at least one of the axial directions so as to be immovable is provided. The first step portion and the second step portion that are in contact with each other are provided as the axial direction restricting portion. As a result, the axial restricting portion can be formed in a relatively simple stepped portion shape such as the first stepped portion and the second stepped portion, and as a result, an inexpensive fuel supply pump while preventing the axial displacement between the cam ring portions. Is obtained.

  In the invention according to claim 4, the axial direction restricting portion has a concave portion provided in one of the cam ring portions and a convex portion provided in the other of the cam ring portions and fitted into the concave portion. It is characterized by.

  In such an invention, the cam ring part is assembled along the sliding surface of the cam and assembled into an annular cam ring. However, since the cam and the cam ring are accommodated in the cam chamber of the housing, the cam ring part is attached to the annular cam ring. At the time of assembling the cam ring, the axial direction restriction portion provided between the cam ring portions may be hidden in the housing. For example, in the case where the axial direction restricting portion is composed of a first stepped portion and a second stepped portion and is a second stepped portion that abuts against the first stepped portion only in one of the axial directions, the cam ring portion is In the assembled state with the annular cam ring, it cannot be confirmed whether or not the first step portion and the second step portion are in contact with each other so as not to move in the axial direction. There is concern that they may not be in contact.

  On the other hand, in the invention according to the fourth aspect, as the axial direction restricting portion, the adjacent cam ring portions are provided with the concave portion and the convex portion that fits into the concave portion, so that, for example, the assembled cam ring has a predetermined annular shape. By confirming that it is formed, it is possible to confirm that the concave portion and the convex portion as the axial direction regulating portion are fitted without directly viewing the axial direction regulating portion. Therefore, the cam ring portions can be assembled into an annular cam ring while the axial movement of the cam ring portions is ensured.

  Further, as in the invention according to claim 5, the concave portion and the convex portion are provided with a tapered portion at at least one of the corner portion on the opening end side of the concave portion and the corner portion on the distal end side of the convex portion. Is preferably provided.

  According to this, since at least one of the corner on the opening end side of the concave portion and the corner on the tip end side of the convex portion is provided with a tapered portion, the cam ring portions are assembled to each other. In some cases, the recesses and the projections can be fitted together even if there is a deviation in the axial direction, so that they can be assembled following the taper part. It can be easily guided to the fitting state of the part. Therefore, it is possible to prevent the cam ring portions from being displaced in the axial direction and to improve the assembling workability for assembling the annular cam ring.

  Further, as the axial direction restricting portion, as in the invention described in claim 6, the axial restricting portion is disposed between the shaft end portion of the cam ring and the housing, and has a restricting member capable of sliding relative to the cam ring. Also good. According to this, it is possible to provide a regulating member that sandwiches the cam ring portion assembled in an annular shape in the axial direction without providing a regulating portion in the cam ring portion itself, and even with such a regulating member, The axial displacement can be prevented.

  The invention according to claim 7 is provided with a radial restricting portion for restricting the mutual movement of the cam ring portions in the radial direction, the radial restricting portion is provided on the outer peripheral side of the cam ring, and the plunger is camped via the cam ring. It has a biasing member for biasing the radially inner end of the plunger to the cam so as to be pressed against the cam.

  In this invention, in order to drive the plunger that reciprocates in the radial direction, the cam ring transmits the driving force of the drive shaft to the plunger. In such a cam ring, the cam ring portions assembled in an annular shape may move (relatively) in the radial direction. However, according to the invention described in claim 7, the biasing force of the biasing member that biases the radially inner end of the plunger to the cam as the radial restricting portion that restricts the radial movement between the cam ring portions. Therefore, it is possible to regulate the radial movement between the cam ring portions without increasing the number of constituent members.

  The invention according to claim 8 is characterized in that a plurality of plungers are arranged along the outer periphery of the cam ring, and the cam rings are divided into the same number as the number of plungers.

  In this invention, since the cam ring is divided into the same number as the number of plungers, there is a region where a radial force acts from the plunger every time the plunger reciprocates in the radial direction in the divided part where the cam ring is divided. Can be arranged. Therefore, during driving of the fuel supply pump, the cam ring can be maintained in an annularly connected state by using the radial acting force due to the reciprocating movement of the plunger.

  In the invention according to claim 9, the housing has an insertion hole into which the cylinder portion is inserted and fitted, and the outer size of the cam ring is formed smaller than the size of the insertion hole. And

  According to such a configuration, since the outer size of the cam ring is formed smaller than the size of the insertion hole into which the cylinder portion is inserted and fitted in the housing, the divided portion into which the cam ring is divided is also inserted. It becomes possible to insert into the hole. For example, in the insertion hole of the housing, the divided part of the cam ring is inserted from the outer opening of the insertion hole, the divided part is overlapped with a part of the sliding surface of the cam, and the cylinder part assembled with the plunger is used as the insertion hole. By mounting, the divided portion can be pressed and assembled to the sliding surface of the cam. According to this, the structure by which the divided part of the cam ring is sandwiched between the cam and the plunger and the divided parts are annularly arranged can be manufactured relatively easily.

  In the outer shell, the corner of the cam ring is preferably formed in a cylindrical part that can be inserted into the insertion hole.

  In this invention, the outer peripheral wall of the cam ring is formed in a polygonal shape composed of, for example, a flat flat surface slidably contacting the plunger and an arcuate curved surface. There are corners on the outer peripheral surface. Since the corner portion side of such a cam ring is formed into a cylindrical portion that can be inserted into the insertion hole, the divided portion of the cam ring can be smoothly inserted into the insertion hole. As a result, the divided portion of the cam ring can be inserted into the insertion hole. It is possible to obtain an excellent assembling workability at the time of assembling work for inserting from the outer opening and superimposing the divided portion on the sliding surface of the cam.

  In the invention according to claim 11, the drive shaft includes both shaft end portions sandwiching the cam in the axial direction, and one of the shaft end portions has a drive force input portion for receiving the drive force of the internal combustion engine. The other end of both shafts is provided with a pre-feeding section that sucks up the fuel from the fuel tank, pre-pressurizes it, and supplies the pre-pressurized fuel to the pressurizing chamber and the cam chamber. It is characterized by that.

  According to the invention of the eleventh aspect, the three bearing parts of the both shaft end portions sandwiching the cam portion and the cam portion in the axial direction on the drive shaft are divided into the cam portion, one of the shaft end portions, and the other. The bearing bushes that support the shaft can be individually enlarged according to the required level of seizure resistance, and the assemblability is not impaired by the expansion of the outer diameter of these bearing bushes.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the component corresponding in each embodiment.

(First embodiment)
1 to 4 show an example in which a fuel supply pump according to an embodiment of the present invention is applied to a fuel supply pump used in a common rail fuel injection device for a vehicle. The common rail fuel injection device mainly includes a fuel tank, a fuel supply pump 1, a common rail (not shown), and a fuel injection valve. The high pressure fuel supplied from the fuel supply pump 1 is accumulated in the common rail, High-pressure fuel is distributed to fuel-provided injection valves provided in each cylinder of the internal combustion engine, and injected into the combustion chamber of the cylinder. The fuel tank and the fuel supply pump 1 constitute a fuel supply device that supplies high-pressure fuel to the common rail and the fuel injection valve.

  The fuel tank stores normal pressure fuel, and the fuel supply pump sucks up the normal pressure fuel from the fuel tank and pressurizes and pumps the fuel to form high pressure fuel to be supplied to the common rail. is there.

  As shown in FIGS. 1 and 2, the housing 2 of the fuel supply pump 1 includes a housing body 20, a cylinder head 30, and a bearing cover 50. The housing body 20 and the bearing cover 50 are made of aluminum. The cylinder head 30 is made of iron and has a cylinder portion 31 that supports a plunger 35 as a movable member so as to be able to reciprocate.

  A plunger sliding hole 31 a that supports the plunger 35 so as to be able to reciprocate is formed inside the cylinder portion 31, and an outer peripheral portion of the cylinder portion 31 is inserted into an insertion hole 29 that communicates with the cam chamber 21 of the housing body 20. Contained. A pressurizing chamber 32 is formed by the plunger sliding hole 31 a of the cylinder portion 31, the end surface of the valve member 37 a of the check valve 37, and the end surface of the plunger 35.

  The housing body 20 is formed with a support hole 28 for inserting and supporting the bearing cover 50 in the axial direction, and the support hole 28 communicates with the cam chamber 21.

  The bearing cover 50 is fixed to the housing body 20 by a fixing member such as a bolt illustrated by a broken line in FIG. 1, and one of both shaft end portions of the drive shaft 80 (left shaft end portion in FIG. 1). A bearing bush (hereinafter referred to as a first bearing bush) 51 that pivotally supports the driving force input portion 81 is housed. A housing bush 20 (hereinafter referred to as a second bearing bush) 52 that supports the feed pump drive unit 82 on the other side of the drive shaft (the right shaft end in FIG. 1) is housed in the housing body 20.

  The first bearing bush 51 and the second bearing bush 52 are press-fitted and fixed to the bearing cover 50 and the housing body 20, respectively, and the bearing cover 50 is fixed to the housing body 20 by the fixing member. The bush 51 and the second bearing bush 52 are arranged coaxially. A gap between the bearing cover 50 and the driving force input portion 81 of the driving shaft 80 is sealed with an oil seal 53. The inner peripheral surfaces of the first bearing bush 51 and the second bearing bush 52 that pivotally support the driving force input portion 81 and the feed pump driving portion 82 correspond to the shaft hole portion of the housing described in the claims.

  The drive shaft 80 includes a drive force input unit 81, a feed pump drive unit 82, and a cam 83 that forms an eccentric section with respect to the rotation axis 80j of the drive shaft 80. The drive force input unit 81 and the feed pump drive The portion 82 is rotatably supported by the first bearing bush 51 and the second bearing bush 52. In FIG. 1, the first bearing bush 51 and the second bearing bush 52 have substantially the same inner diameter, but the inner diameter D2 of the second bearing bush 52 is smaller than the inner diameter D3 of the first bearing bush 51. It is good also as a structure to do (D2 <D3). In such a case, the driving force input part 81 may be called a “large diameter part” and the feed pump driving part 82 may be called a “small diameter part”.

  The cam 83 has a circular cam profile, and is formed between the driving force input portion 81 and the feed pump driving portion 82 so as to be eccentric with respect to the central axis 80j of the driving force input portion 81 and the feed pump driving portion 82. ing. 1 and 2, the cam 83 is integrally molded with an eccentric shaft 83 j giving an eccentric amount δ to the rotation axis 80 j of the drive shaft 80.

  In the present embodiment, the positional relationship among the driving force input unit 81, the feed pump driving unit 82, and the cam 83 is set as follows. In the outer peripheral surface (hereinafter referred to as cam sliding surface) 83a of the cam 83, the cam sliding surface side where the eccentric shaft 83j moves away from the rotational axis 80j is radially outward from the outer peripheral surfaces of the driving force input portion 81 and the feed pump driving portion 82. In addition, the cam sliding surface side opposite to the cam sliding surface side is radially inward from the outer peripheral surfaces of the driving force input portion 81 and the feed pump driving portion 82.

  On the inner wall of the housing main body 20 and the side wall of the bearing cover 50, annular washer members 93 and 94 that are in sliding contact with the axial end surface of the cam 83 are provided. The washer members 93 and 94 are made of a metal material having wear resistance different from that of the housing body 20 and the bearing cover 50. Both the axial end surface of the cam 83 and the axial end surfaces of the washer members 93, 94 are arranged at a predetermined interval, and both come into sliding contact with each other when a thrust force acts on the drive shaft 80. The washer members 93 and 94 correspond to the regulating members described in the claims.

  The driving force input unit 81 of the driving shaft 80 is installed in a driving force transmission system that transmits the driving force of the crankshaft of the internal combustion engine to a camshaft or the like. A gear or a pulley (hereinafter, a helical gear in this embodiment) is fitted. The driving shaft 80 transmits the driving force of the internal combustion engine to the driving force input unit 81 via a helical gear. In the case of a helical gear, the driving shaft 80 swings in the axial direction of the driving shaft 80. A force or thrust force acts on the drive shaft 80.

The feed pump drive unit 81 of the drive shaft 80 is provided with the feed pump 22 as a preliminary pumping unit, and the front end of the feed pump drive unit 81 and the feed pump 22 are directly or indirectly via a joint member or the like. It is connected.
(Preliminary pumping section)
The feed pump 22 is a low-pressure supply pump that sucks fuel from a fuel tank and preliminarily pressurizes (hereinafter referred to as prepressurization), and the prepressurized fuel is supplied to a pressurizing chamber 32 on the pumping unit side described later. To supply. The structure of the feed pump is not limited to the inner gear type pump, but is a known pump structure such as a vane type pump. The fuel discharged from the feed pump 22 (hereinafter referred to as feed fuel) is adjusted so as to keep the feed pressure as a “preliminary pressure” of the fuel constant by a pressure adjusting device such as a regulator (not shown). A part of the feed fuel is supplied as positive pressure fuel to the cam chamber 21 through a throttle portion (not shown).

(Pumping part)
The pumping section of the fuel supply pump 1 includes a pressurizing chamber 32, a cam 83 corresponding to the eccentric section of the drive shaft 80, a plurality of (in this embodiment, two as shown in FIG. 2) plungers 35, A cam ring 90 is provided between the cam 83 and the plunger 35 and serves as a “transmission member” that transmits the driving force of the drive shaft 80 to the plunger 35. The feed fuel discharged from the feed pump 22 is further pressurized. Pressurize and feed.

  As shown in FIGS. 1 and 2, the plungers 35 are arranged at substantially equal intervals around the drive shaft 80 along the cam sliding surface 83 a of the cam 83. In this embodiment, the two plungers 35 are arranged on opposite sides in the radial direction with the drive shaft 80 interposed therebetween.

  At the radially inner end of the plunger 35, an “umbrella that can slide and move relative to the sliding contact portion 95 on the outer wall side of the cam ring 90 in the vertical direction (the left-right direction in FIG. 2) of FIG. The tappet part 35a as a "part" is integrally molded. That is, the shaft end portion on the radially inner side of the plunger 35, that is, the end portion of the tappet portion 35a, and the end portion of the sliding contact portion 95 of the cam ring 90 are formed by planar end surfaces that are parallel to each other. The relative sliding movement of the surface can be performed smoothly.

  The cam ring 90 is formed in a polygonal shape (in this embodiment, a quadrangular shape) in which the outer peripheral wall includes a planar end surface corresponding to the sliding contact portion 95 and a curved end surface formed in an arc shape. Is formed in a circular shape. An inner peripheral wall of the cam ring 90 is provided with a circular cam 83 and a bearing bush (hereinafter referred to as a third bearing bush) 92 that is slidably annular. The third bearing bush 92 is an inner peripheral wall of the cam ring 90. It is fixed to.

  Between the tappet portion 35 a of the plunger 35 and the cinder head 30, a spring 36 is disposed along the axial direction of the cylinder portion 31, and the axially inner end portion of the plunger 35 is a sliding contact portion 95 of the cam ring 90. It is always pressed toward The urging force of the spring 36 and the acting force that the plunger 35 receives in the radial direction due to the fuel pressure in the pressurizing chamber 32 (hereinafter referred to as fuel acting force) restricts the rotation of the cam ring 90 and rotates eccentrically.

  In other words, the cam ring 90 revolves around the rotation axis 80 j of the drive shaft 80 according to the movement of the cam 83 caused by the rotation of the drive shaft 80. Moreover, as described above, the cam ring 90 is always pressed by the fuel acting force of the plunger 35 and the urging force of the spring 36, so that it can rotate relative to the cam 83, but the cam ring 90 itself rotates ( Only the cam 83 rotates in the revolving cam ring 90 without rotation.

  Here, the pumping section is configured so that the feed fuel is sucked into the pressurizing chamber 32 when the plunger 35 moves downward in the figure in FIG. 1, and the fuel in the pressurizing chamber 32 moves when the plunger 35 moves upward in the figure. Is pressurized and pumped to increase the fuel to a fuel pressure equivalent to the fuel injection pressure. The amount of fuel pressurized in the pressurizing chamber 32 corresponding to the fuel injection pressure is controlled by a fuel metering valve (not shown) disposed between the suction valve 37 and the feed pump 22 in the fuel passage 34 on the suction side. Adjusted. The adjusted flow rate, that is, the amount of fuel sucked into the pressurizing chamber 32 is set to a fuel amount corresponding to the discharge amount of the high-pressure fuel supplied to the common rail and the fuel injection valve.

  As shown in FIG. 1, check valves 37 and 38 are provided in the fuel passage 33 on the suction side and the fuel passage 34 on the discharge side of the pressurizing chamber 32, respectively. 37 restricts the inflow and outflow of fuel to the pressurizing chamber 32 except when the pressurizing chamber 32 is sucked, and the check valve (hereinafter referred to as a discharge valve) 38 is prevented from flowing back to the pressurizing chamber 32. To do.

  1 and 2, in each plunger 35, an assembly including the cylinder head 30, the spring 36, and the plunger 35 constitutes a pump element as a “pressure feeding unit”. In this pump element, the cylinder portion 31 of the cylinder head 30 is inserted into the insertion hole 29 of the housing body, and then fixed to the housing body 20 with a fixing member such as a bolt, whereby the plunger 35 is attached to the cam ring 90 and the drive shaft 80. The tappet portion 35a is pressed against.

  The basic configuration of the fuel supply pump 1 has been described above. Hereinafter, a characteristic configuration of the fuel supply pump 1 will be described.

(Characteristic configuration)
As shown in FIGS. 1, 2, and 4, in this embodiment, the cam ring 90 is divided into a plurality (two in this embodiment) and assembled to the cam 83. That is, the cam ring 90 includes a third bearing bush 92 and a cam ring main body 91 to which the third bearing bush 92 is fixed. The cam ring 90 is divided into semicircular divided portions (hereinafter referred to as cam ring portions) 90a and 90b by the same divided surface (not shown). It is divided into In other words, the third bearing bush 92 is formed in a half bearing shape, and the third bearing bush 92 is fixed to the cam ring main body 91 by joining, whereby the cam ring portions 90a and 90b are formed.

  Here, the third bearing bush 92 is a slide bearing having a bearing back metal 92a as a “bearing base material” and a bearing alloy 92b formed integrally with the bearing back metal 92a. The bearing back metal 92a is an iron-based material such as a pressed steel plate. The bearing alloy 92b is made of a non-ferrous metal material such as a copper alloy or an aluminum alloy. The bush 92 is formed by pressing or casting a bearing alloy 92b on the inner peripheral surface of the bearing back metal 92a, or formed by sintering each metal powder of the bearing back metal 92a and the bearing alloy 92b. It is.

  In such a sliding bearing, the bearing back metal 92a ensures the strength against the load of the bush 92, and the bearing alloy 92b is compatible with the sliding portion of the drive shaft 80 (sliding surface 83a of the cam 83) and seizure resistance. Etc. are secured. When the inner diameter D3 of the bush 92 is enlarged, the surface pressure is reduced, so that the seizure resistance to the load on the bush 92 is improved without improving the materials of the bearing back metal 92a and the bearing alloy 92b.

  The cam ring portions 90a and 90b having the third bearing bush 92 having the above-mentioned half bearing shape are coupled and fixed to each other when the cam ring portions 90a and 90b are assembled to form an annular shape. No connection fixing means is required. This is because the divided surface divides the portion of the end surface other than the flat end surface that forms the sliding contact portion 95 between the outer peripheral wall of the cam ring 90 and the tappet portion 35 a of the plunger 35. In addition, the sliding contact portion 95 of the cam ring 90 has an assembly structure in which a pressing force by which the plunger 35 presses the sliding contact portion 95 against the cam 83 is applied by the urging force of the spring 36. It is possible to connect both of the 90a and 90b on the dividing surface without joining them.

  The fuel supply pump 1 having the above configuration can obtain the following characteristic operations and actions.

(Characteristic operation and action)
When driving force is obtained from a crankshaft or the like of the internal combustion engine and the driving shaft 80 is driven to rotate, the cam 83 rotates, and the cam ring 90 revolves without rotating due to this rotation. Then, each plunger 35 to which driving force is transmitted from the drive shaft 80 via the cam ring reciprocates (up and down movement in FIGS. 1 to 3) through the plunger sliding hole 31 a in the cylinder portion 31.

  At this time, only the fuel metered by the fuel metering valve is sucked into the pressurizing chamber 32. Therefore, depending on the amount of fuel sucked, the position of the upper plunger 35 (top dead center position) in FIG. During a considerable period before and after, both the fuel acting force by the plunger pumping operation and the urging force of the spring 35 act on the cam ring 90, but other positions of the plunger 35 on the lower side (bottom dead center position) in FIG. 3, only the urging force of the spring 35 may act on the cam ring 90 in the front and back periods corresponding to the positions of the upper and lower plungers 35 in FIG. Even in such a case, since the connection state of both the cam ring portions 90a and 90b is not released, the cam ring 90 itself does not rotate (spin), and only the cam 83 is within the revolving cam ring 90. The third bearing bush 92 is pivotally supported and can rotate smoothly.

  Now, the “inner diameter increase” of the bearing bushes 51, 52, 92 (in other words, the “outer diameter increase” of the power input portion 81, the feed pump drive portion 82, and the cam 83) on the drive shaft 80 is performed. Advantageous features of the present embodiment in this case will be described below.

(Advantageous features related to assembly of the fuel supply pump 1)
First, in the comparative example of FIG. 18, the assembly property in the case of the annular cam ring 990 according to the prior art will be described. For example, the drive force input unit 981 and the feed pump drive unit 982, which are each section of the drive shaft 980, are formed in a large diameter part and a small diameter part, respectively, and the outer peripheral surface of the feed pump drive part 982 that is the small diameter part is a cam 983. When any of the outer peripheral surfaces 983a of the cam ring 90 is formed on the radially inner side, the cam ring 90 is inserted into the third bearing bush 992 of the cam ring 90 from the axial direction c in FIG. In addition, a cam 983 can be slidably incorporated.

  However, when the outer diameter of the cam 983 or the outer diameter of the feed pump drive unit 982 is enlarged, the outer peripheral surface of the feed pump drive unit 982 is radially outer than the outer peripheral surface 983a of the cam 983 as shown in FIG. 18A, even if the cam ring 990 is inserted from the axial direction c in FIG. 18A, the axial end surface of the cam ring 990 becomes the axial end surface of the cam 983 as shown in FIG. have a finger in the pie. As a result, the cam 983 cannot be slidably incorporated in the third bearing bush 992 of the cam ring 990.

  On the other hand, in the present embodiment, the cam ring 90 having an annular shape is formed in cam ring portions 90a and 90b corresponding to “pieces” obtained by dividing the ring, so that the cam ring is attached to the fuel supply pump 1 during assembly. The cam ring portions 90a and 90b can be individually arranged on a predetermined portion (cam 83) of the drive shaft 80 in which 90 is incorporated.

  That is, the cam ring portions 90a and 90b can use any one of the methods a, b, and c that are assembled to the drive shaft 80 in the arrow directions a, b, and c in FIG. It is. In particular, the cam ring portions 90 a and 90 b can be assembled from the radial direction toward the outer peripheral surface 83 a of the cam 83 as in the method a of FIG.

  As a result, as shown in FIG. 5B, both cam ring portions 90 a and 90 b mounted on the cam 83 are formed on the annular third bearing bush 92 and the cam ring main body 91 that cover the entire outer periphery 83 a of the cam 83. It is done.

  Therefore, for example, even when the outer peripheral surface of the feed pump drive unit 82 is formed to be disposed radially outside the outer peripheral surface 83a of the cam 983, the cam ring 90 is fed to the drive shaft 80 as in the prior art. Since it is not necessary to insert from the pump drive part 82 side, the interference between the axial end surface of the cam ring 90 and the axial end surface of the cam, that is, the third bearing bush 92 and the cam ring main body 91 are prevented from interfering with the drive shaft 80. be able to.

  In FIG. 5A, method b and method c are a combination of axial movement and radial movement as the assembly direction of the cam ring portions 90a and 90b. The cam ring portions 90a and 90b are moved in the axial direction from the side to the cam 83 in the axial direction. In the method c, the cam ring portions 90a and 90b are moved in the axial direction from the feed pump drive portion 82 side to the cam 83 in the axial direction.

(Assembly method of fuel supply pump 1)
In the method of the prior art, the cam ring 990 is inserted into the drive shaft 980 from the feed pump drive unit 82 side by the method c, and incorporated into the cam 83 along the axial direction. Therefore, as a procedure for incorporating the cam ring 990 into the drive shaft 980, it is necessary to incorporate the cam ring 990 into the drive shaft 980 before assembling at least the drive shaft 980 into the housing body 20.

  On the other hand, in this embodiment, it is possible to incorporate the cam ring 90 into the fuel supply pump 1 by selecting one of the methods a, b, and c. The structure of the housing 2 of one embodiment of the fuel supply pump 1 is constructed by the method a or the method b because the housing part on the first bearing bush 51 side is separately formed by the bearing cover 50 as shown in FIG. It will be. In addition, when the housing part by the side of the 2nd bearing bush 52 is comprised separately from the housing main body as a structure of the housing 2, it will assemble | attach by the method a or the method c.

  Hereinafter, one aspect of the embodiment of the assembling method will be described with reference to FIGS.

(One example of assembly method)
In a state after the drive shaft 80 is assembled to the housing body 20 and before the pump element for each plunger 35 is assembled to the housing body 20 (hereinafter referred to as “first state”), the cam ring portions 90a and 90b are It is inserted from the opening of the support hole 28 of the housing body 20 and overlapped with the outer peripheral surface 83 a of the cam 83. Subsequently, the pump element is inserted from the insertion hole 29 of the housing body 20, and the pump element is assembled and fixed or temporarily assembled to the housing body 20.

  By assembling and fixing or temporarily assembling the pump element to the housing main body 20, the tappet portion 35a on the plunger 35 side is pressed against the sliding contact portion 95 of the cam ring portions 90a and 90b, so both of the cam ring portions 90a and 90b are As shown in FIG. 5B, the spring 36 is connected by the urging force F (see FIG. 5B), and the connected state is maintained.

  When the cam rings 90a and 90b are inserted into the support holes 29, the rotational position of the cam 80 of the drive shaft 80 is such that the rotational shaft center 80j and the eccentric shaft 83j are arranged along the vertical direction in FIG. Alternatively, it may be in any position such as being arranged along the horizontal direction as shown in FIG.

  In the first state, when the rotational position of the cam 83 is at the position shown in FIG. 2 or the like, it is preferable that the driving force input portion 81 of the driving shaft 80 is held. The magnitudes of the urging forces F of the springs 36 of the upper and lower plungers 35 and 35 in FIG. 2 are different, but the urging forces F of the two are not balanced across the drive shaft 80. In addition, it is possible to prevent the drive shaft 80 from being inclined.

  According to this exemplary method, the cam ring 90 can be easily assembled to the drive shaft 80 without interfering with the drive shaft 80, and the cam ring 90 can be compared in the assembled state such as the first state. It can be manufactured easily.

  Here, the spring 36 corresponds to the urging member described in the claims.

  In the present embodiment described above, the cam ring 90 is divided at two points in the circumferential direction. In addition, the cam ring 90 has a cam ring main body 91 and a third bearing bush 92, and the third bearing bush 92 is divided together with the cam ring main body 91, and these constitute cam ring portions 90a and 90b which are divided portions of a half bearing shape. is doing. The third bearing bush 92 and the cam ring main body 91, that is, the cam ring portions 90a and 90b having such a configuration can be assembled to the sliding surface 83a of the cam 83 from the radial direction.

  Therefore, the annular cam ring 990 is inserted from a shaft end portion such as the feed pump drive portion 82 of the drive shaft 80 as in the prior art, and the cam ring 990 is directed toward the cam 83 and the rotary shaft plug 80j of the drive shaft 80 is inserted. Therefore, it is not necessary to mount the cam 83 while shifting it radially. In the exemplary drive shaft of this embodiment, when the outer diameter of the portion other than the cam corresponding to the shaft hole portion or the outer diameter of the cam is increased, the outer diameter surface of the portion other than the cam of the drive shaft, that is, the feed pump drive It is possible to prevent the cam ring 990 and the cam 83 from interfering with each other as in the conventional annular cam ring 990 structure, assuming that the outer peripheral surface of 82 is radially outward from the outer diameter surface 83a of the cam 83. it can.

  In addition, the outer diameters of the drive force input unit 81 and the feed pump drive unit 82, which are sections of the drive shaft 80, which are sections other than the cam 83 and the cam 83, are not limited to other outer diameters. The bearing bushes 51, 52 and 92 corresponding to the respective sections of the drive shaft 80 can be enlarged and the surface pressure can be reduced, so that seizure resistance at each bearing portion and The strength can be improved.

  According to the above, the cam ring 90 having the third bearing bush 92 and the cam ring main body 91 does not interfere with the drive shaft 80, and the assembling property of the third bearing bush 92 to the drive shaft 80 is ensured. A fuel supply pump having a bearing structure with excellent seizure resistance and strength at the bearing portion can be obtained.

  Further, in the present embodiment described above, the washer members 93 and 94 provided on the inner wall of the housing body 20 and the side wall of the bearing cover 50 constituting the housing 2 are spaced apart from each other in the axial end surfaces of the cam ring 90. It is placed and placed.

  When the cam ring portions 90a and 90b are overlaid on the cam 83 and assembled into the annular cam ring 90, the cam ring portions 90a and 90b are assembled in the radial direction toward the outer peripheral surface 83a of the cam 83. At this time, the cam ring portion 90a , 90b may be displaced in the axial direction.

  However, in this embodiment, since both axial end surfaces of the cam ring portions 90a and 90b are sandwiched between the washer members 93 and 94, the cam ring portions 90a and 90b are substantially moved in the axial direction by the washer members 93 and 94. Is regulated. Thereby, it is possible to prevent the axial displacement between the cam ring portions 90a and 90b.

  Further, in the present embodiment described above, the pressing spring 36 is always provided so that the shaft end portion (the tappet portion 35a) on the radially inner side of the plunger 35 faces the sliding contact portion 95 of the cam ring portions 90a and 90b. The cam ring portions 90 a and 90 b are urged against the sliding surface 83 a of the cam 83 by the urging force F of the spring 36 on the plunger 35 side.

  In order to reciprocate the plunger 35 in the radial direction, the cam ring 90 transmits the driving force of the drive shaft 80 to the plunger 35. In such a cam ring 90, the cam ring portions 90a and 90b assembled in an annular shape are connected to each other. May shift in the radial direction.

  However, in this embodiment, the tappet portion 35a of the plunger 35 is directed toward the cam 83 on the radially inner side as a radial direction restricting portion that restricts the radial movement between the cam ring portions 90a and 90b. The biasing force of the spring 36 that biases 90b is used. Thus, the relative radial movement of the cam ring portions 90a and 90b is restricted without increasing the number of constituent members of the fuel supply pump 1. Accordingly, radial displacement between the cam ring portions 90a and 90b can be prevented.

  In the cam ring 90, the cam ring portions 90a and 90b that maintain the annular connection state without being displaced in the radial direction by the biasing force F of the spring 36 on the plunger 35 side as described above have the following advantageous effects. can get.

  Generally, if seizure occurs in the sliding contact portion 95 between the tappet portion 35a of the plunger 35 and the cam ring 90 due to poor lubrication or the like, the plunger 35 has a direction different from the radial driving force for driving the plunger 35. Since abnormal rotational torque is applied, there is a possibility of expanding the failure of the plunger 35 being broken.

  On the other hand, in the cockling 90 of the present embodiment, the cam ring portions 90a and 90b are restricted from moving in the radial direction by the biasing force F, and as a result, the cam ring portions 90a and 90b are connected in an annular shape. It is maintained at the magnitude of the urging force F.

  If a seizure failure occurs in the sliding contact portion 95 between the plunger 35 and the cam ring portions 90a and 90b as described above, an abnormal force acts on the cam ring portions 90a and 90b due to the seizure failure. However, with respect to such an abnormal force, the cam ring portions 90a and 90b that are connected in an annular shape are separated from each other by the urging force, and the annular connection state of the cam ring portions 90a and 90b is released. As a result, the cam 83 of the drive shaft 80 idles, so that the drive force of the drive shaft 80 transmitted to the plunger 35 via the cam ring 90 can be nullified. Therefore, even if a seizure failure occurs in the sliding contact portion 95 between the plunger 35 and the cam ring 90, the failure can be limited to a range that causes the seizure. Therefore, it does not expand to the failure that the plunger 35 is broken.

(Second Embodiment)
A second embodiment is shown in FIG. The second embodiment is a modification of the first embodiment. In the second embodiment, in the cam ring 90, an example in which a gap is provided between the split surfaces of the half-shaped third bearing bush 92 out of the half-shaped third bearing bush 92 and the cam ring main body 91. It is shown.

  As shown in FIG. 6, the split surfaces of the cam ring main body 91 are in contact with each other, and the split surfaces of the half-divided third bearing bush 92 are not in contact with each other. 92c is formed. The gap 92c is formed in a gap penetrating the third bearing bush 92 in the axial direction, and the gap 92c functions as a “lubricating oil passage”.

  Moreover, in this embodiment, as in the first embodiment, a sliding gap for forming a lubricating oil film is surely provided between the inner peripheral surface of the third bearing bush 92 and the outer peripheral surface 83a of the cam 83. Is secured.

  In the fuel supply pump 1 having such a configuration, fuel as “lubricating oil” is stored in the cam chamber 21, but the fuel supply to be supplied to the sliding gap between the third bearing bush 92 and the cam 83. The amount can be increased by providing the gap 92c. Also by this, the seizure resistance between the third bearing bush 92 and the cam 83 can be further improved.

(Third embodiment)
A third embodiment is shown in FIG. The third embodiment is a modification of the first embodiment. In the third embodiment, an example is shown in which the cam ring portions 90a and 90b are provided with axial restriction portions that prevent axial displacement between the cam ring portions 90a and 90b.

  As shown in FIGS. 7A to 7C, the cam ring portion 90a is provided with a recess 91aa that opens to the split surface, and the cam ring portion 90a has a protrusion that protrudes with respect to the split surface. And a convex portion 91bb that fits into the concave portion 91aa. The fitting shape of the concave portion 91aa and the convex portion 91bb is formed in the fitting groove portion and the fitting projection portion having a two-sided width. Thus, by providing the concave portions 91aa and the convex portions 91bb on the cam ring portions 90a and 90b, axial displacement between the cam ring portions 90a and 90b can be surely prevented.

  Specifically, among the half-shaped third bearing bush 92 and the cam ring main body 91, the third bearing bush 92 is half-shaped, and the divided surfaces are in contact with each other. And the said recessed part 91aa and convex part 91bb are provided in the division parts 91a and 91b of the cam ring main body 91, respectively. As a result, the arcuate length of the divided portion of the half bearing third bearing bush 92 does not become more than a semicircle.

  In addition, as shown in FIG. 7C, the divided portion 91a is provided with a convex portion 91bb, and among the inner walls of the divided portion 91a, only the inner wall surface portion of the convex portion 91bb is provided on the third bearing bush 92. It is formed by stealing meat along the tangential direction with respect to the outer peripheral surface.

  By configuring as described above, the cam ring portions 90a and 90b can be easily stacked on the cam 83, and excellent assembling properties can be secured.

(Fourth embodiment)
A fourth embodiment is shown in FIG. The fourth embodiment is a modification of the third embodiment. The fourth embodiment shows another example in which the cam ring portions 90a and 90b are provided with the axial direction restricting portions that prevent the axial displacement of the cam ring portions 90a and 90b.

  As shown in FIG. 8, the fitting shape of the concave portion 91aa and the convex portion 91bb is formed in a triangular fitting groove portion and a fitting projection portion. The concave portion 91aa and the convex portion 91bb have triangular tapered portions such as such a triangular fitting shape, and the respective tapered portions of the fitting groove portion and the fitting projection portion are configured to be fitted. However, the same effect as the third embodiment can be obtained.

  In such an invention, when it is desired to reduce the size of the cam ring 90, the meat stealing portion of the convex portion 91bb corresponds to the fragile portion of the cam ring main body 91. It is possible to limit the range of the convex portion 91bb protruding from the end, and as a result, the meat stealing portion of the convex portion 91bb that becomes the fragile portion can be suppressed as small as possible.

(Fifth embodiment)
A fifth embodiment is shown in FIG. The fifth embodiment is a modification of the first embodiment. The fifth embodiment shows another example in which the cam ring portions 90a and 90b are provided with the axial direction restricting portions that prevent the axial displacement between the cam ring portions 90a and 90b.

  As shown in FIG. 9, step portions 91aa and 91bb that are in axial contact with each other are provided in the cam ring portions 90a and 90b as axial restriction portions. Specifically, the first step portion 91aa is provided in the divided portion 91a of the cam ring main body 91 on the cam ring portion 90a side, and the first step portion 91aa and the shaft are provided in the divided portion 91b of the cam ring main body 91 on the cam ring portion 90b side. A second step portion 91bb that abuts in the direction is provided.

  According to this, since the step portions 91aa and 91bb can be formed in a comparatively simple shape called a step to form the structure of the axial direction restricting portion in the cam ring portions 90a and 90b, the axial direction between the cam ring portions 90a and 90b Thus, the cam ring can be manufactured at low cost while preventing the misalignment, and thus the inexpensive fuel supply pump 1 can be obtained.

(Sixth embodiment)
A sixth embodiment is shown in FIG. The sixth embodiment is a modification of the third embodiment. In the sixth embodiment, an example in which the axial direction restricting portion that prevents the axial displacement between the cam ring portions 90a and 90b is provided in the cam ring portions 90a and 90b, and the structure of the axial restricting portion is easily assembled. Is shown.

As shown in FIGS. 10A and 10B, in the convex portion 91bb having a dihedral width shape, a tapered portion 91bc is provided at the corner on the tip side. According to this configuration,
When the cam ring portions 90a and 90b are assembled to each other, the concave portions 91aa and the convex portions 91bb can be fitted to each other even if there is a deviation in the axial direction. In other words, the axial displacement can be corrected, and it can be easily guided to the fitting state of the concave portion 91aa and the convex portion 91bb. Therefore, the cam ring portions 90a and 90b can be prevented from being displaced in the axial direction, and the assembly workability for assembling the annular cam ring 90 is improved.

  In the concave portion 91aa, a tapered portion 91ac is formed at a corner portion corresponding to the corner portion on the tip end side of the convex portion 91bb.

(Seventh embodiment)
A seventh embodiment is shown in FIG. The seventh embodiment is a modification of the third embodiment. In the seventh embodiment, as a “lubricating oil passage”, a gap 92 c is provided between the split surfaces of the half-divided third bearing bush 92, and partly between the split surfaces of the half-split cam ring body 91. An example in which a gap 91c is provided is shown.

  As shown in FIGS. 11A and 11B, the axial end surfaces of the convex portions 91 aa and the concave portions 91 bb are in contact with each other on the split surface of the cam ring main body 91. Thus, a sliding gap for forming a lubricating oil film is reliably ensured between the inner peripheral surface of the third bearing bush 92 and the outer peripheral surface 83a of the cam 83.

  Moreover, as shown in FIG. 11 (b), a gap 92 c is provided between the split surfaces of the half-shaped third bearing bush 92, and the cam ring main body 91 is split other than the convex portions 91 aa and the concave portions 91 bb. A gap 91c is provided between the surface portions. The gap 91c is formed in a gap penetrating the split surface portion of the cam ring main body 91 in the axial direction.

  In general, there may be a case where a predetermined axial gap between the both axial end surfaces of the cam 83 and the washer members 93 and 94 is formed small due to a relatively large thrust force acting on the drive shaft 80. The cam ring 90 shares the washer members 93 and 94 together with the cam 83 as an axial direction restricting portion. Therefore, the amount of fuel introduced as lubricating oil may be reduced from the axial opening of the sliding gap between the third bearing bush 92 and the cam 83 via the predetermined small gap in the axial direction. There is.

On the other hand, in the present embodiment, since the sliding gap and the gap 92c between the third bearing bush 92 and the cam 83 are both introduced into the cam chamber 21 through the axial openings, There is a possibility that the amount of fuel supplied to the sliding gap between the three bearing bush 92 and the cam 83 may be reduced.
As shown in FIG. 11 (b), the gaps 91c and 92c form a lubricating oil passage for introducing fuel radially inward. Thereby, the amount of fuel can be increased, and as a result, the seizure resistance between the third bearing bush 92 and the cam 83 can be further improved.

(Eighth embodiment)
An eighth embodiment is shown in FIG. The eighth embodiment is a modification of the seventh embodiment. In the eighth embodiment, as a “lubricating oil passage”, a gap 92 c is provided between the split surfaces of the half-divided third bearing bush 92, and partly between the split surfaces of the half-split cam ring body 91. Another example in which a gap 91c is provided is shown.

  As shown in FIGS. 12A and 12B, the divided surfaces of the cam ring main body 91 are in contact with the divided surfaces other than the convex portions 91 aa and the concave portions 91 bb. Thus, a sliding gap for forming a lubricating oil film is reliably ensured between the inner peripheral surface of the third bearing bush 92 and the outer peripheral surface 83a of the cam 83.

  In addition, as shown in FIG. 12B, a gap 92 c is provided between the split surfaces of the half-shaped third bearing bush 92, and the split surface portions of the convex portions 91 aa and the concave portions 91 bb on the split surface of the cam ring main body 91. A gap 91c is provided in the minute. The gap 91c is formed in a gap penetrating in the axial direction in the convex portion 91aa and the concave portion 91bb of the cam ring main body 91. The gap 91c and the gap 91c form a lubricating oil passage through which fuel is introduced radially inward via the gap between the stealing portion of the convex portion 91aa and the third bearing bush 92.

  With the above configuration, the same effect as that of the seventh embodiment can be obtained.

(Ninth embodiment)
A ninth embodiment is shown in FIG. The ninth embodiment is a modification of the first embodiment. In the ninth embodiment, an example in which the size of the outline of the cam ring 90 is made smaller than the size of the insertion hole 29 of the housing body 20 is shown.

  There are two methods for assembling the cam ring portions 90a and 90b to the cam 83 of the drive shaft 80. One method is to move the cam ring portions 90a and 90b radially inward in the cam ring 90 and 83, the cam ring portions 90a and 90b are assembled to the outer circumferential surface of the cam 83 by combining the movement in the radial direction and the movement inward in the radial direction. This is a method b that is assembled on 83a.

  As described in the example of the assembling method of the first embodiment, the method b is a method by which the fuel supply pump 1 can be manufactured relatively easily in a pump factory that manufactures the fuel supply pump 1.

  However, when disassembling and assembling for maintenance of the fuel supply pump 1 at a maintenance factory in a market other than the pump factory, a relatively simple assembly for disassembly and assembly used at the maintenance factory A tool may not be assembled properly. For example, the method b assumes that the drive shaft 80 is assembled to the housing body 20 and before the bearing cover 50 is assembled to the housing body 20. Therefore, it is necessary to hold the drive force input portion 81 of the drive shaft 80 so that the drive shaft 80 does not tilt due to the biasing force F of the plunger 36. Moreover, holding the drive shaft 80 without tilting means that, in the drive shaft 80 inserted into the second bearing bush 52 on the main body 20 side, the central axis of the inner peripheral surface of the second bearing bush 52 and the rotation of the drive shaft 80 The axis line 80j is held so as to be substantially coaxial. Depending on the assembly tool, it may be difficult to hold the driving force input portion 81 of the drive shaft 80 so as to satisfy such holding conditions.

  In the present embodiment, as shown in FIGS. 13 and 15, the size of the outline of the cam ring 90 is set smaller than the size of the insertion hole 29 of the housing body 20.

  According to such a configuration, the outer size of the cam ring 90 is formed smaller than the size of the insertion hole 29 into which the cylinder portion 31 corresponding to the pump element of each plunger 35 is inserted and fitted. Cam ring portions 90 a and 90 b which are “pieces” obtained by dividing the cam ring can also be inserted into the insertion hole 29.

  Moreover, the cam ring portions 90 a and 90 b are inserted from the outer opening of the insertion hole 29, and the cam ring portions 90 a and 90 b are overlapped with the outer peripheral surface 83 a of the cam 83. Then, the cylinder part 31 to which the pump element, that is, the plunger 35 is assembled, is mounted in the insertion hole 29, whereby the cam ring parts 90a and 90b are pressed against the outer peripheral surface 83a of the cam 83 and assembled. It is. In other words, even after the drive shaft 80 is inserted and assembled between the bearing bushes 51 and 52 of the housing body 20 and the bearing cover 50 and the housing body 20 and the bearing cover 50 are assembled and fixed, the method c is used. The above assembly method can be performed.

  According to the above configuration, in the cam ring 90, the cam ring portions 90a and 90b are sandwiched between the cam 83 and the plunger 35, and the cam ring portions 90a and 90b are arranged in an annular shape with a relatively simple assembly tool. Even so, it can be manufactured relatively easily.

  Further, in the cam ring 90 having a quadrangular shape as in the present embodiment, the outer peripheral wall of the cam ring 90 is formed in a quadrangular shape including, for example, a flat flat surface that is in sliding contact with the plunger 35 and an arc-shaped curved surface. However, corner portions are present on the outer peripheral wall of the cam ring 90 that forms such an outline.

  On the other hand, in this embodiment, the corner portion side of such a cam ring 90 is formed in a cylindrical portion 91d that can be inserted into the insertion hole 29 as shown in FIG. 14, so that the cam ring portions 90a and 90b are formed in the insertion hole 29. Thus, it is possible to smoothly insert, and as a result, excellent assembling workability can be obtained in the assembling work by the method a.

  Further, the corners of the cam ring 90 may limit the size reduction of the cam ring 90. For example, the sliding area of the sliding contact portion 95 of the cam ring 90 may be too small due to the size reduction of the cam ring 90.

  On the other hand, in the present embodiment, the corner portion on the outer peripheral wall side that is divided by the dividing surface in the outline of the cam ring 90 follows the outer peripheral shape of the tappet portion 35a as shown in FIG. It is formed in the cylindrical part 91d which exhibits a large semicircle. Accordingly, as shown in FIGS. 13 and 15, the cam ring 90 can be inserted into the insertion hole 29 while suppressing a decrease in the sliding area of the sliding contact portion 95 of the cam ring 90 with respect to the tappet portion 35 a of the plunger 35. Can be achieved.

  Further, the insertion hole 29 may be larger than the size of the hole for inserting the cylinder portion 31 of the prior art, but as a condition for expanding the hole, as shown in FIG. When the holding position in the rotation direction is held in a state where the rotation axis 80j and the eccentric shaft 83j are arranged in the illustrated vertical direction, the cam ring portions 90a and 90b can be inserted into the insertion hole 29 by the method a. It is preferable to make this a condition.

  According to this, the expanded insertion hole 29 is arranged substantially coaxially with the cylinder portion 31, that is, the plunger sliding hole 31a. As a result, it is possible to realize an assembly method in which the cam ring portions 90a and 90b can be stably sandwiched between the plunger 36 and the cam 83 by the biasing force F of the plunger 36 while minimizing the expansion of the insertion hole 29. According to the assembling method based on such hole machining conditions, for example, as shown in FIG. 3, the holding position of the drive shaft 80 is compared to the case where the rotation axis 80j and the eccentric shaft 83j are held in the illustrated horizontal direction. This is because the urging force F of the plunger 36 substantially acts on the axis of symmetry of the plunger 36, the cam ring portions 90a and 90b, and the cam 83.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described above, the present invention is not construed as being limited to these embodiments, and can be applied to various embodiments without departing from the scope of the present invention. .

  (1) For example, in the present embodiment described above, the number of plungers 35 constituting the pump element is two, and the outer peripheral wall shape of the cam ring 90 is a substantially square shape. The outer peripheral wall shape of the cam ring 90 may be a triangular shape composed of a flat flat surface corresponding to the sliding contact portion 95 and a curved end surface as shown in FIG. The cam ring 90 may have any polygonal shape.

  When the outer peripheral wall of the cam ring 90 is a polygonal shape such as a triangular shape as shown in FIG. 16, an outer peripheral wall portion corresponding to the sliding contact portion 95 is used as a dividing surface for dividing the cam ring 90 into a plurality of cam ring portions 90 a, 90 b, 90 c. It is preferable to provide in the outer peripheral wall part corresponding to the said end surface other than.

  The sliding contact portion 95 is subjected to the fuel acting force by the pressure feeding operation of the plunger 35 and the urging force F of the spring 36, and the outer peripheral wall portion corresponding to the end face is an intermediate position between the plungers 35 on the outer peripheral wall. Since the dividing surface is formed at the intermediate position, the surface pressure in the vicinity of the dividing surface can be lower than that of the sliding contact portion 95, and the edge of the dividing surface of the third bearing bush 92 can be obtained. This is because the oil film of the lubricating oil does not break.

  (2) Further, in the present embodiment described above, the cam ring 90 is divided into two for the two plungers 35. However, the present invention is not limited to this, and as described above, the cam ring 90 is divided into three for the three plungers. The cam ring 90 may be divided into two as long as the cam ring 90 is divided into the same number as the plurality of plungers.

  In this invention, since the cam ring is divided into the same number of cam ring portions as the number of plungers, the cam ring portion is arranged so that there is a region where a radial force acts from the plunger each time the plunger reciprocates in the radial direction. can do. Therefore, during driving of the fuel supply pump, the cam ring portion can be maintained in an annularly connected state by utilizing the radial acting force due to the reciprocating movement of the plunger.

  (3) In the sixth embodiment described above, in the concave portion 91aa and the convex portion 91bb that are fitted to each other, the tapered portion 91bc is provided at the corner portion on the tip side of the convex portion 91bb. A tapered portion 91bc may be provided at the corner on the opening end side.

  (4) In the seventh and eighth embodiments described above, as the “lubricating oil passage”, a gap 92 c is provided between the split surfaces of the half-shaped third bearing bush 92, and the half-shaped cam ring body 91 is provided. An example in which the gap 91c is provided in a part between the divided surfaces has been described. In these embodiments, the gap 91c guides the fuel radially inward, and the opening is formed in a lubricating oil passage that penetrates through the divided surface portion in the axial direction. Not limited to this, the gap 91c is formed in a lubricating oil passage that guides the fuel radially inward as shown in FIG. 17, but the lubricating oil passage is not configured to penetrate between the divided surface portions in the axial direction. It may be divided into two lubricating oil passages. In this case, the recess 91aa can be dispensed with the taper portion 91ac at the corner portion corresponding to the corner portion having the taper portion 91bc shape on the tip side of the convex portion 91bb. As a result, the seizure resistance can be further improved, an inexpensive cam ring 90 can be manufactured, and the assembly workability of the cam ring portions 90a and 90b can be achieved by the guide function by the tapered portion 91bc provided at the corner on the tip side of the convex portion 91bb. The effect that it improves can be acquired.

  (5) In the present embodiment described above, the tappet portion 35a that is in sliding contact with the sliding contact portion 95 of the cam ring 90 and relatively slidably moves is integrally formed with the plunger 35. Not only this but a structure which forms a plunger and a tappet part by another member, and a plunger and a tappet part engage may be sufficient.

  (6) In the ninth embodiment described above, as a precondition for expanding the insertion hole into which the pump element having each plunger 35 as a constituent member is inserted, “the holding position in the rotational direction of the drive shaft 80 is the rotational axis In the assembled state in which 80j and the eccentric shaft 83j are held in the vertical direction, the cam ring portions 90a and 90b can be inserted into the insertion hole 29 by the method a ". However, the cam ring portions 90a and 90b can be inserted into the insertion hole 29 in the assembled state in which the holding position of the drive shaft 80 is held with the rotation axis 80j and the eccentric shaft 83j horizontally. It may be a condition that “it is”.

It is a longitudinal cross-sectional view which shows the fuel supply pump by 1st Embodiment of this invention, Comprising: It is the II sectional view taken on the line of FIG. It is the II-II sectional view taken on the line in FIG. It is sectional drawing which shows the operation state different from FIG. It is a front view which shows the cam ring in FIG. FIGS. 5A and 5B are schematic views for explaining the characteristic part of the first embodiment of the present invention, in which FIG. 5A is a perspective view showing a process of assembling the cam ring to the drive shaft, and FIG. It is explanatory drawing explaining the assembled | attached state. It is a front view which shows the cam ring concerning the fuel supply pump by 2nd Embodiment. It is a figure which shows the cam ring concerning the fuel supply pump by 3rd Embodiment, Comprising: Fig.7 (a) is a disassembled perspective view, FIG.7 (b) is a side view, FIG.7 (c) is FIG.7 (b). It is CC sectional view taken on the line. It is a perspective view which shows the cam ring concerning the fuel supply pump by 4th Embodiment. It is a perspective view which shows the cam ring concerning the fuel supply pump by 5th Embodiment. It is a figure which shows the cam ring concerning the fuel supply pump by 6th Embodiment, Comprising: Fig.10 (a) is a disassembled perspective view, FIG.10 (b) is a side view. It is a figure which shows the cam ring concerning the fuel supply pump by 7th Embodiment, Comprising: Fig.11 (a) is a side view, FIG.11 (b) is the BB sectional drawing in Fig.11 (a). It is a figure which shows the cam ring concerning the fuel supply pump by 8th Embodiment, Comprising: Fig.12 (a) is a side view, FIG.12 (b) is the BB sectional view taken on the line in Fig.12 (a). It is sectional drawing which shows the fuel supply pump by 9th Embodiment. It is a perspective view which shows the cam ring in FIG. It is a schematic diagram for demonstrating the characteristic part of 9th Embodiment. It is a perspective view which shows the cam ring concerning other embodiment. It is a side view which shows the cam ring concerning other embodiment. FIG. 5A is a schematic diagram for explaining a comparative example, FIG. 5A is a perspective view illustrating a process of assembling the cam ring to the drive shaft, and FIG. 5B is an explanatory diagram illustrating a state where the cam ring is assembled to the drive shaft. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel supply pump 2 Housing 20 Housing main body 21 Cam chamber 22 Feed pump 28 Support hole 29 Insertion hole 30 Cylinder head 31 Cylinder part 31a Plunger sliding hole 32 Pressurization chamber 35 Plunger 35a Tappet part 36 Spring 37 Suction valve (check valve) )
37a Valve member 38 Discharge valve (check valve)
50 Bearing cover 51 First bearing bush (bearing bush)
52 Second bearing bush (bearing bush)
80 Drive shaft 81 Drive force input part 82 Feed pump drive part 83 Cam (Eccentric section)
83a Outer peripheral surface (sliding surface)
90 Cam ring 90a, 90b Cam ring part (divided part)
91 Cam ring body 92 Third bearing bush (bearing bush)
93, 94 Washer member (regulator member)
95 Sliding part

Claims (11)

A plunger that pressurizes and pumps the fuel sucked into the pressurizing chamber;
A drive shaft in which the cam is eccentrically formed integrally;
A cam ring that is annularly provided on the outer periphery of the cam, revolves without rotating with the rotation of the drive shaft, and transmits a driving force from the drive shaft to the plunger;
A housing having a cam chamber that houses the cam and the cam ring, a shaft hole portion that rotatably supports the drive shaft, and a cylinder portion that supports the plunger so as to reciprocate in the radial direction and forms the pressurizing chamber. When,
In the fuel supply pump, wherein the drive shaft is pivotally supported from the outside by a bearing bush provided in the cam ring and the shaft hole portion,
The fuel supply pump according to claim 1, wherein the cam ring having the bearing bush is divided at a plurality of locations along a circumferential direction of the cam ring.   2. The fuel supply pump according to claim 1, wherein the divided cam ring portion in the cam ring includes an axial direction restricting portion that restricts the axial movement of the cam ring portions.   The axial restricting portion is provided on one of the cam ring portions and on the other of the cam ring portions, and moves to at least one axial direction with respect to the first step portion. The fuel supply pump according to claim 2, further comprising a second step portion that abuts against the second step portion.   The axial direction restricting portion includes a concave portion provided in one of the cam ring portions and a convex portion provided in the other of the cam ring portions and fitted into the concave portion. The fuel supply pump according to claim 2.   5. The fuel according to claim 4, wherein at least one of the corner on the opening end side of the concave portion and the corner on the tip side of the convex portion is provided with a tapered portion. Supply pump.   The said axial direction control part is arrange | positioned between the axial end part of the said cam ring, and the said housing, It has a control member which can be slid relatively with respect to the said cam ring, The any one of Claim 2 to 5 characterized by the above-mentioned. The fuel supply pump according to one item. A radial direction restricting portion for restricting the radial movement of the cam ring portions;
The radial restricting portion is provided on the outer peripheral side of the cam ring and biases a biasing member that biases the radially inner end of the plunger against the cam so as to press the plunger against the cam via the cam ring. The fuel supply pump according to any one of claims 1 to 6, wherein the fuel supply pump is provided. A plurality of the plungers are arranged along the outer periphery of the cam ring,
The fuel supply pump according to any one of claims 1 to 7, wherein the cam ring is divided into the same number as the number of the plungers. The housing has an insertion hole for inserting and fitting the cylinder portion,
The fuel supply pump according to any one of claims 1 to 7, wherein a size of an outer shell of the cam ring is smaller than a size of the insertion hole.   10. The fuel supply pump according to claim 9, wherein a corner portion side of the cam ring in the outer shell is formed into a cylindrical portion that can be inserted into the insertion hole. The drive shaft includes both shaft ends sandwiching the cam in the axial direction,
One of the shaft end portions has a driving force input portion that receives the driving force of the internal combustion engine,
The other of the shaft ends is provided with a pre-feeding section that sucks up fuel from a fuel tank and pre-pressurizes it, and supplies pre-pressurized fuel to the pressurizing chamber and the cam chamber. The fuel supply pump according to any one of claims 1 to 10, wherein:

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