KR101629903B1 - Load reduction - Google Patents

Abstract

A method and apparatus for selectively providing a fluid communication path between a plunger element and a contact area of an intermediate element that drives the plunger element is disclosed. The fluid communication path is suitable for lubricant flow such that the contact area is occasionally lubricated. The apparatus includes an elongated plunger element including a first end region, an intermediate element comprising a contact region disposed to be selectively adjacent and selectively in contact with the other end region of the plunger element, Member. The spring sheet member urges the other end region away from the intermediate element during a portion of a motion cycle of the plunger element. Thereby, a fluid communication path is provided between the abutment surface of the other end region and the contact region.

Description

Load Reduction {LOAD REDUCTION}

The present invention relates to a method and apparatus for selectively providing a fluid communication path through which lubricant flows between two moving parts to a predetermined position. In particular, but not exclusively, the present invention relates to plunger and tappet configurations. An elastic spring seat is used to separate the plunger and tappet by a short distance at a particular point in the plunger motion cycle. The momentary separation causes the lubricant to flow into the space formed between the plunger and the tappet from the surrounding area.

In known pump assemblies, an intermediate element (sometimes also referred to as an intermediate drive member, often in the form of a tappet) transfers drive from the cam mechanism to the pumping plunger. The pumping plunger is used to pressurize the fluid in the pumping chamber for delivery to a predetermined location. For example, the fluid may be the engine fuel of a diesel engine fuel injection system.

The tappet is used to reduce the lateral force applied to the pumping plunger so that generally the pumping plunger is driven along the corresponding longitudinal axis of motion in the anteroposterior direction by reciprocating movement by the tappet. Tappets are well known and are generally cup-shaped elements having a cylindrical side wall and a solid base. Vents can be provided in the sidewalls and / or base of the tappet so that lubricating fluid can flow from the circumference of the cam mechanism to the area within the tappet. This ensures that the free movement of the tappet within the tappet bore in the housing does not interfere with the force. Accordingly, a pump capable of operating at a high pressure employs a reciprocating plunger for working with the fluid to be pumped. The plunger is moved forward during the pumping stroke by mechanically applying a load to the opposite end of the plunger by the tappet. During the return stroke of the plunger's motion cycle, the plunger is held against the tappet by a spring called a return spring.

During the pumping stroke of the cycle, the contact load between the tappet and the plunger may be very high, with less lateral forces resulting in lubrication breakdown and fretting wear in the contact zone. The fact that the surfaces of the conventional system are held together in a continuous manner prevents the lubricating flow into the contact zone between the end of the plunger and the contact area of the tappet. This causes the wear debris to be retained, which can further wear the juxtaposed surface over time. The patent application DE1 0201 0041 002 discloses an apparatus as in the preamble of claim 1.

It is an object of the present invention to at least partially alleviate the above-mentioned problems.

It is an object of certain embodiments of the present invention to provide a method and apparatus that sometimes provides a fluid communication path of the type in which a lubricant can flow between the contact area of the intermediate element and the plunger element.

It is an object of certain embodiments of the present invention to at least momentarily press the plunger away from the tappet at one or more points in time during the exercise cycle of the plunger.

It is an object of certain embodiments of the present invention to provide a pump capable of reducing the rate of fretting and abrading between juxtaposed surfaces on a part by allowing the lubricant to selectively flow between the end of the plunger element and the contact area of the intermediate element, Assembly.

The purpose of certain embodiments of the present invention is to reduce the fretting and wear rate in the pump assembly by causing the contact area to flush with fresh lubricant before each load cycle.

The purpose of certain embodiments of the present invention is to allow a small gap to be selectively opened between parts within the pump assembly when the part is unloaded.

It is an object of certain embodiments of the present invention to provide a squeeze film between the intermediate element in the pump assembly and the opposed surface of the plunger element.

It is an object of certain embodiments of the present invention to provide a method of lubricating between an intermediate element that provides drive to the plunger element and the plunger element of the pump assembly.

According to a first aspect of the present invention there is provided an apparatus for selectively providing a fluid communication path between a plunger element and a contact area of an intermediate element that drives the plunger element,

An elongated plunger element comprising a first end region;

An intermediate element comprising a contact area disposed to selectively press adjacent to the other end area of the plunger element; And

In the other end region, pressurizes the other end region away from the intermediate element during a portion of the motion cycle of the plunger element to provide an fluid communication path between the abutment surface of the other end region and the contact region And an elastic spring sheet member for elastically deforming the elastic member.

Preferably, the intermediate element includes a tappet received for reciprocating sliding movement within the housing bore of the pump housing of the pump assembly.

Preferably, the tappet includes at least one through bore in a cylindrical sidewall and / or base wall, the through bore providing a fluid pathway connected to the fluid communication path.

Preferably, the fluid communication path provides a lubricating fluid between the abutment surface and the contact area at the end of a return cycle of the plunger element.

Preferably, the first end region of the plunger element is positionable within the blind end of the pump bore of the pump head of the pump assembly,

The intermediate element further includes a drive surface that can be driven by a cam or cam rider element of the pump assembly to press the contact area against the mating surface.

Preferably, the apparatus further comprises a return spring member for urging the surface of the spring seat element away from the pump head of the pump assembly.

Preferably, the spring sheet member and the plunger element are integrally formed, or the spring seat member is fixed to the plunger element for movement with the plunger element.

Preferably, according to a second aspect of the present invention, there is provided a pump assembly,

A pump housing having an axially extending opening and at least one housing bore extending radially from the opening;

One or more intermediate elements each accommodated for reciprocating sliding movement within the corresponding housing bore, the intermediate element including an inner chamber region;

At least one pump head having a blind end and a pump bore fixed to the pump housing;

An elongated plunger element in each chamber region operable through a corresponding intermediate element in use, the elongate plunger element including a first end region for pressurizing fluid in a pumping chamber provided by a corresponding pump bore and an opposite end region;

A cam and / or cam rider element having, in the axially extending opening, an inner surface operable with the cam drive shaft and an outer surface operable with the drive surface of the intermediate member; And

In the other end region of the corresponding plunger element, pressurizing the other end region away from the intermediate element during a portion of the motion cycle of the plunger element to cause the fluid communication path between the abutment surface of the other end region and the contact region Wherein the elastic spring sheet member is provided with an elastic spring sheet member.

Preferably, the spring sheet member and the plunger element are integrally formed, or the spring sheet member is retained in the plunger element for movement therewith.

According to a third aspect of the present invention there is provided a method of lubrication between a plunger element of a pump assembly and an intermediate element that provides drive to the plunger element,

Driving a first end region of the plunger element in a first reciprocating motion relative to the blind end of the pump bore of the pump head, wherein the contact region of the intermediate element proximate the other end region of the plunger element is selectively moved in another reciprocating motion Driving the first end region of the plunger element to pressurize;

Pressing the plunger element away from the intermediate element during a portion of the motion cycle of the plunger element via the spring seat member in the other end region of the plunger element; And

Providing a lubricating fluid between the abutment surface of the other end region and the contact region as the other end region is urged away from the intermediate element.

Preferably, the method further comprises cooling and removing debris from between the abutment surface and the contact area via the lubricating fluid.

Preferably, the method further comprises providing a squeeze film layer between the abutment surface and the contact area via the lubricating fluid.

Preferably, the method further comprises opening and closing a gap between the abutment surface and the contact area in each cycle of the plunger.

Advantageously, a portion of the cycle further comprises a pump cycle portion in which the pump bore is compressed, wherein the first reciprocating motion comprises compressing the pump bore.

Preferably, the method further comprises pressing the other end region via a spring seat member formed integrally with the plunger or via a spring seat member secured to the plunger element for movement with the plunger element.

Certain embodiments of the present invention provide the advantage of providing a fluid communication path between the contact area of the intermediate element, such as a tappet, and the end of the plunger. This causes the lubricant to be drawn into the area between the opposing faces to cool, lubricate and remove the residues. Also, by providing a squeeze film between the opposing faces as the opposing faces are closed together again, the opposing faces are spaced apart for a longer period than allowed by conventional systems. Such an extended period reduces wear caused by drive motions and / or unavoidable lateral movements as part of the reciprocating pumping motion.

Certain embodiments of the present invention provide a method for reducing fretting and wear and for removing debris in the high pressure head of a pump assembly.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings.
1 shows a pump assembly,
2 is a view showing a pump head, a return spring and a tappet,
3 is another view of a pump head, return spring and tappet,
Figure 4 shows the plunger end in the inner chamber of the tappet,
Fig. 5 is a view showing the feature shown in Fig. 4 and the spring sheet member. Fig.
In the drawings, like reference numerals refer to like parts.

Figure 1 shows a pump assembly 100. The pump assembly includes a main pump housing (101) having an axially extending opening (102). The opening extends in the in-page direction shown in Fig. A camshaft (not shown) having a rotating shaft 103 drives the eccentrically mounted cam 104 mounted in the opening.

The main pump housing 101 has first, second and third radially extending apertures or through bores 105a, 105b and 105c, each of which includes an axially extending opening 102 at the radially inner end. Of course, other numbers of through bores may be used in accordance with other specific embodiments of the present invention. The radially outer ends of the respective housing bores 105a, 105b and 105c receive the corresponding pump heads 110a, 110b and 110c. Since each pump head is substantially the same, it will be referenced by only the upper pump head 110a shown in FIG. 1 and shown in another drawing.

Fig. 2 shows details of the parts of the pump head 110a. The pump head has a head part 200 which is a substantially rectangular body. A substantially cylindrical central region extends from the lower region 201 of the pump head. The cylindrical extension 202 surrounds the substantially cylindrical pump bore region 203. The pump bore 203 has a blind end 204 at a location where at least one valve 205 is located. The pump bore 203 also has an open end 206 to provide an open mouth of the extension of the pump head. The pump bore 203 provides a pumping chamber and the space of the pumping chamber is defined by the blind end 204 of the bore and the first end 210 of the plunger 211. The plunger is an elongate shaft-like member that slides in the back and forth direction within the cylindrical bore 203 in the pump head. As the upper end surface 212 of the first end 210 of the plunger moves upward in the direction indicated by arrow A in Fig. 2, the volume of the pumping chamber decreases. Likewise, as the plunger moves in the direction along the axis of movement opposite the direction indicated by the arrow A in Fig. 2, the volume of the pumping chamber increases.

On the lower face of the pump head, a substantially cylindrical cut-out area 215 is provided at the center. Which is used to locate and hold the first end 220 of the return spring 221. The return spring holds the tappet away from the pump head in the unlocked state and is compressed as the tappet is pressed against the pump head during the pump stroke portion of the cycle. The space 215 under the pump head also provides a gap for the upper circular surface 230 of the cup-shaped tappet 231. Thus, the blind end of the plunger bore, along with the outer end face of the plunger, can be delivered with a comparatively low pressure ointment, and the plunger can be moved in the direction of the plunger as the plunger is driven to perform the pumping stroke upon rotation of the rider positioned on the cam or cam Thereby forming a pump chamber that pressurizes the fuel to a relatively high level, as described below.

The tappet 231 is a substantially hollow body having a cylindrical sidewall 232 extending substantially from the circumferential region of the circular base 233. The base and the side wall are integrally formed. The lip of the side wall 232 forms a circular surface that is urged upwardly toward the pump head during pumping. The base 233 provides a blind end of the inner chamber 240 formed in the tappet. At least one through bore 250 is formed circumferentially around the side wall of the tappet to allow fluid to flow from the outer region surrounding the tappet body to the interior region within the chamber 240. The through bore may be circular or church window style, and the like.

The spring seat 260 is located at the other end 261 of the plunger 211. The spring seat 260 shown in FIG. 2 is retained at the end of the plunger by an interference fit, but the spring seat may be integrally formed with the shaft-like plunger body, or alternatively, It is possible. The spring seat and the plunger move together in one unit. The upper surface 262 of the spring seat seats the other lower end 263 of the return spring.

As shown in Fig. 1, the drive shaft cooperates with the cam 104 and operates with an optional, commonly working tubular cam rider extending coaxially with the cam, as shown in Fig. On the outer surface, the cam rider has first, second and third flat surfaces (called flat). Each one of the flats operates with the base surface of the tappet 231 for a corresponding one of the plungers. As the tappet is operatively coupled to the plunger, rotation of the shaft causes the cam rider to ride over the surface of the cam, thereby imparting drive to both the tappet and the plunger. As the tappet 231 is driven, a certain lateral sliding movement is permitted between the lower surface 27 of the tappet base and the rider's flat. Alternatively, a slipper surface may be provided to facilitate such sliding movement. A lubricating fluid (such as fuel) is provided in the bore 105 and the opening 102 of the housing to slide the tappet to limit wear due to friction.

As the cam is driven, the tappet is reciprocated within the opening 105 and the plunger is reciprocated within the plunger bore 203. There is thus a first reciprocation of the tappet in the housing bore and another reciprocation of the plunger in the pump bore.

Thereby, the tappet and the pumping plunger are driven together to cause the plunger to perform a pumping cycle including the pumping stroke, while radially outward from the center camshaft, which reduces the volume in the pump chamber 203 Toward the pump head). During the pumping stroke, the pumping plunger is driven inward in the plunger bore and the fuel in the pump chamber is pressurized to a high level. During the subsequent plunger return stroke, the tappet and the plunger are urged radially inward, i.e. toward the center of the housing and away from the pump head. This return motion is caused by the elastic properties of the return spring, thereby pressing the tappet away from the pump head. During the return stroke of the plunger and its corresponding tappet, the plunger is forced outwardly from the plunger bore, and the relatively low pressure fuel can be allowed to fill the associated pump chamber via the valve.

Thus, providing a plunger return spring urges the plunger to perform its return stroke and further ensures that contact is maintained between the cam rider's flat and the tappet during the pumping cycle. The tappet and the plunger perform a sinusoidal motion of the cycle and are driven at a predetermined frequency. Preferably, the maximum frequency is about 130 Hz. Preferably, the maximum frequency is about 120 Hz. The tappet has a range of travel between bottom-dead-center and top-dead-center. Preferably, the travel range is about 15 mm or less. Preferably, the range of travel is about 10 mm or less. The tappet acts as an intermediate element between the cam and / or cam rider element providing the drive and the plunger driven in reciprocating manner in the pump bore provided by the pump head.

3 shows the pump head, tappet, and return spring shown in Fig. 2 in detail. In particular, FIG. 3 helps clarify how the church window opening 250 is formed in the radially innermost end region of the tappet. Although three openings are shown in FIG. 3, different shapes and numbers of openings are possible in accordance with other specific embodiments of the present invention. The opening is formed from the base and cylindrical sidewalls of the tappet by the incision region 300. 3 also helps illustrate how the pump head is substantially rectangular in shape, but other shapes and configurations are possible in accordance with other specific embodiments of the present invention. The pump head can be retained in the pump housing 101 via bolts or other fastening mechanisms that, in use, extend through the opening 301 in the pump head. As shown in Fig. 3, the tappet provides an inner chamber surrounding the end of the return spring. The other end of the return spring is retained in the pump head 110 at its upper end.

Figure 4 shows how the plunger extends into the chamber 240 formed in the tappet through the open end 206 of the pump bore. The lower end of the plunger 211 has a generally circular abutment surface end 400. Which abuts the central contact area 401 on the upper surface 402 of the base of the tappet. As shown in Fig. 4, the central contact area 401 can be raised slightly relative to the enclosed area of the upper surface 402 of the base of the tappet.

Spring seat 260 is a substantially circular ring-shaped body formed of an elastic material. Preferably, the spring sheet is formed of hardened steel. The cross section of the spring seat is formed with a radially outermost leg 403 (with respect to the axis of the plunger) having a lower annular contact surface 404 that rests on the upper surface 404 of the base of the tappet. Accordingly, the contact point 405 between the base of the tappet and the spring seat restrains the movement of the spring seat in the direction shown by arrow B in Fig. The remaining body of the spring seat is in the form of a disk having a concave profile on the underside thereof. Partially teardrop-shaped recesses on the lower portion of the spring seat help to flex the spring seat. The top surface 262 of the spring seat has an upper annular rib 410 extending as a ring-shaped projection.

A small gap 420 may be opened between the contact area 401 of the base of the tappet and the end face 400 of the plunger, as shown in Fig. This space 420 provides a short separation between the components. During the pumping process in which the cam rider is pressed against the lower surface 270 of the tappet, the tappet is pushed against the end of the plunger, and the force overcomes the elastic properties of the spring seat. Thus, the plunger and the tappet are effectively positioned together for movement as a single piece. The pumping stroke follows when the cam rider drives the tappet and the plunger in the direction opposite to the arrow B shown in Fig. 4 while the tappet and the plunger move as one. At the end of the pumping cycle, the cam rider stops pressing the tappet (and thus the plunger) in the direction opposite to arrow B. A return spring 221, which is then pressed against the base of the tappet and acts on the upper surface of the spring seat which accompanies the plunger with the base of the tappet, causes movement of the tappet and plunger in the direction of arrow B. At the end of the return stroke, the resilient nature of the spring seat and the presence of the spring seat on the base of the tappet causes the plunger end to momentarily be pulled away from the contact area 401 at the base of the tappet. This separate motion creates a gap 420 that provides a fluid communication path between the zones between the components. The fluid communication path also communicates with the tappet and the chamber 240 within the area surrounding the vent in the tappet 250.

Fig. 5 illustrates the cylindrical nature of the tappet and the circular disk-shape characteristics of the spring seat in more detail. As shown in Fig. 5, the tappet 231 is a cup-shaped element having a cylindrical sidewall extending from a substantially circular base. The upper lip 230 of the tappet's cylindrical side wall provides an open mouth to the tappet and the lip 230 is recessed in a central circular inset region 215 on the lower portion of the pump head body 200 500 in the upward direction toward the pump head. 5 also illustrates how the elevated central region of the upper surface of the base of the tappet can be raised to provide an island 501 having a tappet's contact surface 401 at its upper surface .

The top surface 262 of the spring seat provides the outermost substantially flat ring surface 505 to extend upwardly into the rib region 410 that faces upwardly through the upwardly extending region 506 do. This helps to position / seat the end of the return spring. From the rib moving radially inward toward the plunger, the upper surface of the spring sheet falls into the first recessed area 510 separated from the inner recessed area 511 by the convexed area 512. The radially innermost central region of the spring seat provides a contact area that allows the spring seat to be retained at the end 261 of the plunger, such as through an interface fit. The plunger body and the spring seat may be integrally formed.

According to a particular embodiment of the invention, a spring feature is added between the plunger and the tappet or similar component. This causes a small gap to open between the parts when unloaded. The opening of the small gap acts to attract the lubricant into the gap between the faces. This allows the debris to cool, lubricate and clean on the sides. Also, the flow of lubricant into the contact area provides a squeeze film to be provided. Such a squeeze film helps to keep the opposing faces separately for a longer period of time than is possible with conventional systems. This helps to reduce wear caused by exercise.

The spring effect can be provided by the elastic spring sheet as described above. Alternatively, the pressurizing effect of moving the components in a momentary and spaced manner can be achieved in a variety of other ways. For example, a solid spring seat may include a ring annulus that receives an elastic O-ring.

In the description and claims of the present specification, the terms "comprise" and " comprise "and variations thereof mean" not limited to, " and are not intended to exclude other parts, additives, ingredients, . In the description and claims of this specification, the singular shall include the plural unless the context otherwise requires. In particular, where indefinite articles are used, the present specification should be understood to include plural as well as singular, unless the context requires otherwise.

It should be understood that the features, integers, features, or groups in relation to particular aspects, embodiments, or examples of the present invention are applicable to any other aspect, example, or example described herein unless incompatible. All features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all steps of any method or process disclosed, are to be construed in an encompassing manner, with the exception of combinations in which at least some of the features and / or steps are not mutually exclusive , And may be combined in any combination. The present invention is not limited to any details of any of the above-described embodiments. The present invention is not intended to be limited to any particular novelty or novel combination of features disclosed herein (including any accompanying claims, abstract and drawings), or to any novelty or novel combination of the steps of any disclosed method or process Or a novel combination.

It is the reader's intention to have the benefit of the present disclosure incorporated herein by reference in its entirety, including all publications publicly disclosed herein, whether filed concurrently or in conjunction with this disclosure.

Claims (14)

An apparatus for selectively providing a fluid communication path between a plunger element (211) and a contact area of an intermediate element that drives the plunger element,
An elongated plunger element comprising a first end region (210); And
An intermediate element 231 including a contact area disposed to selectively press adjacent to the other end area 261 of the plunger element,
/ RTI >
The apparatus comprises:
Shaped elastic sheet member (260) having a concave profile on the lower side so as to be able to bend the other end region (261) and to be disposed in the other end region (261), characterized in that a part of the motion cycle of the plunger element (260) that pressurizes the other end region away from the intermediate element (231) to provide a fluid communication path between the abutment surface (400) of the other end region and the contact region (401) )
Lt; RTI ID = 0.0 > 1, < / RTI &
Device.
The method according to claim 1,
The intermediate element includes a tappet 231 received for reciprocating sliding movement within the housing bore 105a of the pump housing 101 of the pump assembly 100. [
Device.
3. The method of claim 2,
Wherein the tappet includes at least one through bore (250) in a cylindrical side wall and / or a base wall, the through bore providing a fluid pathway portion connected to the fluid communication path (420)
Device.
4. The method according to any one of claims 1 to 3,
The fluid communication path 420 provides lubrication fluid between the abutment surface 400 and the contact area 401 at the end of the return cycle of the plunger element 211,
Device.
4. The method according to any one of claims 1 to 3,
The first end region 210 of the plunger element is positionable within the blind end of the pump bore 105a of the pump head 110a of the pump assembly 100,
The intermediate element 231 further includes a drive surface that can be driven by a cam or cam rider element of the pump assembly 100 to press the contact area against the mating surface,
Device.
4. The method according to any one of claims 1 to 3,
Further comprising a return spring member for urging the surface of the spring seat element away from the pump head (110a) of the pump assembly (100)
Device.
4. The method according to any one of claims 1 to 3,
The spring sheet member 260 and the plunger element 211 are integrally formed or the spring seat member 260 is fixed to the plunger element 211 for movement with the plunger element 211. [
Device.
In the pump assembly 100,
A pump housing (101) having an axially extending opening (102) and at least one housing bore extending radially from the opening (102);
At least one pump head (110a) comprising a pump bore (105a) having a blind end and being fixed to the pump housing (101);
A cam and / or cam rider element within the axially extending opening (102) having an inner surface operable with the cam drive shaft and an outer surface operable with the drive surface of the intermediate member; And
The device according to any one of claims 1 to 3,
/ RTI >
Pump assembly.
A method of lubrication between a plunger element (211) of a pump assembly (100) according to claim 8 and the intermediate element (231) providing a drive to the plunger element (211)
Driving the first end region (210) of the plunger element (211) in a first reciprocating motion relative to the blind end of the pump bore (105a) of the at least one pump head (110a) The first end region 210 of the plunger element selectively urging the contact region of the intermediate element 231 proximate to the other end region 261 of the plunger element to another reciprocating motion;
The plunger element 211 is moved away from the intermediate element 231 during a portion of the motion cycle of the plunger element 211 via the spring seat member 260 in the other end region 261 of the plunger element 211. [ ; And
Providing a lubricating fluid between said abutment surface (400) and said contact area (401) of said other end region as said other end region is pressed away from said intermediate element
/ RTI >
Way.
10. The method of claim 9,
Further comprising cooling and removing debris from between the abutment surface (400) and the contact area (401) via the lubricating fluid.
Way.
10. The method of claim 9,
Further comprising providing a squeeze film layer between the abutment surface (400) and the contact area (401) via the lubricating fluid.
Way.
10. The method of claim 9,
Further comprising opening and closing a gap (420) between the abutment surface (400) and the contact area (401) in each cycle of the plunger element (211)
Way.
10. The method of claim 9,
Wherein a portion of the cycle includes an end of a return cycle of the plunger element in which the fluid in the pump bore expands and wherein the first reciprocating motion further comprises a pump cycle portion in which the pump bore is compressed,
Way.
10. The method of claim 9,
Pressing the other end region 261 through a spring seat member 260 integrally formed with the plunger element 211 or through a spring seat member fixed to the plunger element for movement with the plunger element, Including,
Way.

Images