Patent Application
20130153064
This disclosure relates generally to assemblies formed by brazing and, more particularly, to an assembly in which brazing material is stored adjacent the brazed connection and a method of forming such assembly.
Machines often use fluid operated systems for controlling various implement systems of the machine. Such fluid operated systems typically include a control system having one or more control valve assemblies for controlling the flow of hydraulic fluid to and from the implement systems. The control valve assemblies generally include a valve body with a plurality of passages and one or more valve members moveably mounted so as to control the rate of flow through one or more of the passages. The control valve assemblies are often utilized to direct or control the flow of hydraulic fluid having a pressure as high as 5,000 psi. In some instances, the valve bodies are cast with a series of internal passages. In other instances, the valve bodies may be formed of a plurality of plates that are stacked together and oriented such that each plate forms a linear segment along each of the internal passages. In each case, the shape of the internal passages may be limited by the process of forming the valve body.
U.S. Pat. No. 6,305,418 discloses a hydraulic valve that is formed from a plurality of parallel, plate-shaped metal sheets. The metal sheets are brazed together to form the assembly. The metal sheets include holes that are aligned to form segments of the internal passages along their linear axes. Reception channels for brazing material extend over the entire length between end plates of the assembly. Fixing posts may also extend between the end plates to align the sheet metal plates.
The foregoing background discussion is intended solely to aid the reader. It is not intended to limit the innovations described herein, nor to limit or expand the prior art discussed. Thus, the foregoing discussion should not be taken to indicate that any particular element of a prior system is unsuitable for use with the innovations described herein, nor is it intended to indicate that any element is essential in implementing the innovations described herein. The implementations and application of the innovations described herein are defined by the appended claims.
An assembly formed by brazing two or more components together is provided. In one aspect, the assembly includes a first plate member with a first generally planar abutting surface and a second plate member with a second generally planar abutting surface. One of the first abutting surface and the second abutting surface has a plurality of micro reservoirs for storing brazing material. The first abutting surface and the second abutting surface are positioned adjacent each other and are joined by the brazing material.
In another aspect, a method of forming an assembly includes providing a first plate member with a generally planar first abutting surface. The first abutting surface has a plurality of micro reservoirs. Brazing material is inserted into the micro reservoirs. A second plate member with a generally planar second abutting surface is provided. The first plate member and second plate member are positioned with the first abutting surface adjacent the second abutting surface. A brazing material is provided between the first plate member and the second plate member. The first plate member, the second plate member, the brazing layer and the brazing material are heated to braze the first plate member to the second plate member.
Implement system 12 may include a linkage structure utilizing fluid actuators to move work tool 13. More specifically, implement system 12 may include a boom member 15 vertically pivotal relative to frame 16 and propelled by a pair of adjacent, double-acting, boom hydraulic cylinders 17 (only one being shown in
Each of the hydraulic cylinders and the swing motor may be driven by pressurized fluid such as hydraulic fluid. Flow of hydraulic fluid such as oil to and from the fluid actuators may be controlled by one or more hydraulic valve assemblies 30 as depicted in
More specifically, referring to
A first solenoid cavity 51 may extend inwardly from first side 34 of valve body 32 towards the second side 35 of the valve body and a second solenoid cavity 52 may extend inwardly from second side 35 of the valve body towards the first solenoid cavity 51. The central spool bore 33 may be positioned between the additional bore 37 and the pair of aligned solenoid cavities. A compensator bore 53 may extend inwardly from a compensator surface 54 that faces in a direction opposite work surface 46 and towards central spool bore 33.
A plurality of flow passages may be provided within the valve body 32 to connect the central spool bore 33, the additional bore 37, the first solenoid cavity 51, the second solenoid cavity 52 and the compensator bore 53. More specifically, a plurality of first flow passages 55 may extend between and fluidly connect some of the central annuluses 36 of the central spool bore 33 and the additional annuluses 39 of the additional bore 37. Second flow passages 56 may extend between and fluidly connect the compensator bore 53 and others of the central annuluses 36 of the central spool bore 33. A third flow passage 57 may extend between and fluidly connect first solenoid cavity 51 and the first side 34 of valve body 32 adjacent central spool bore 33 for providing hydraulic fluid to first spool bore actuator 71 (
A plurality of holes or passages may be provided in one or both outer faces 61 (only one face being visible in
A first shaft such as central shaft 73 may be slidably positioned within central spool bore 33. Central shaft 73 may be generally cylindrical and include enlarged areas such as shaft annuluses 74. Opposite ends of the central shaft 73 are connected to the first spool bore actuator 71 and the second spool bore actuator 72, respectively, to control movement of the central shaft 73. Movement of the central shaft 73 directs hydraulic fluid to selected ones of the flow passages and permits hydraulic fluid to selectively flow from the valve body 32 through the first work port 43 and the second work port 44. A first lock valve assembly 75 may be positioned within first cartridge cavity 38 and a second lock valve assembly 76 may be positioned within the second cartridge cavity 41. An additional spool 77 may be positioned within additional spool bore 42. First lock valve assembly 75, second lock valve assembly 76 and additional spool 77 may operate to control the flow of hydraulic fluid to and from a fluid actuator (not shown) connected to hydraulic valve assembly 30.
A first solenoid 81 may be positioned along first side 34 of valve body 32 with a portion thereof extending into the first solenoid cavity 51 to control the flow of hydraulic fluid to the first spool bore actuator 71. A second solenoid 82 may be positioned along second side 35 of valve body 32 with a portion extending into the second solenoid cavity 52 to control the flow of hydraulic fluid to second spool bore actuator 72. A compensator 83 may be positioned within compensator bore 53 to further control the flow of hydraulic fluid between adjacent hydraulic valve assemblies 30.
From the foregoing, it can be seen that valve body 32 includes a complex array of passages such as bores, flow passages, ports, cavities and other openings through which hydraulic fluid may flow at relatively high pressures. In one example, the pressure of hydraulic fluid flowing through the hydraulic valve assembly 30 may range from approximately 0 to at least 4,000 psi and may be as high as 5,000 psi. As depicted, valve body 32 may be formed from two or more plate members that are secured together through a brazing process. In the embodiment depicted in
In such a configuration, the connection plane 89 may bisect each of the central spool bore 33, the additional bore 37, the first work port 43, the second work port 44, the additional end bore 45, the first solenoid cavity 51, the second solenoid cavity 52, the compensator bore 53, the first flow passages 55, the second flow passages 56, and the third flow passages 57. In this way, each of those passages may have a segment or portion of their shape intersecting with each of the first abutting surface 87 and second abutting surface 88 so as to form the complete shape of each passage upon brazing the first plate member 85 to the second plate member 86. In some configurations, all or some of the passages of valve body 32 may be formed in one of the first abutting surface 87 or the second abutting surface 88 so that the first plate member 85 and the second plate member 86 are not substantially identical. In other words, it may be possible to form all or some of the passages in one of the abutting surfaces while leaving the other abutting surface generally planar.
As best seen in
As best seen in
Upon heating the first plate member 85, the second plate member 86, and the brazing foil 92 to an appropriate temperature in an appropriate environment, the brazing foil melts and flows along the connection plane 89. This joins the first plate member 85 and the second plate member 86 together along the abutting regions 91. At locations at which segments of passages along the first abutting surface 87 are adjacent segments of passages of the second abutting surface 88, the segments will be joined and sealed along the edges of the segments. In other words, where a first segment of a passage in the first abutting surface 87 and a second segment of a passage in the second abutting surface 88 are aligned, brazing the first plate member 85 to the second plate member 86 will cause the brazing foil to seal the passage along edges of the first segment and the second segment.
As depicted in FIGS. 4 and 8-10, a plurality of bores or micro reservoirs 93 may be provided in each of the abutting regions 91 to fill gap 95. Such micro reservoirs 93 may have brazing material such as a brazing wire 94 inserted therein. Brazing wire 94 may be a copper alloy or another appropriate material. If desired, micro reservoirs 93 may be filled with other types of brazing material such a brazing paste. During the process of joining the first plate member 85 to the second plate member 86, the first plate member and the second plate member are heated to a desired temperature within the desired environment and the brazing material within each micro reservoir 93 melts and the brazing material flows or wicks to the abutting regions 91 of each of the first abutting surface 87 and the second abutting surface 88 to join the first plate member 85 to the second plate member 86.
The dimensions such as the size and depth of the micro reservoirs 93 may be set based upon a number of factors including the size of the gap 95 between the first abutting surface 87 and the second abutting surface 88 as well as the surface area of the first abutting surface and the second abutting surface. Since each opening along the abutting surfaces may reduce the strength of the joint between the abutting surfaces, in some situations it may be desirable to minimize the size and number of the micro reservoirs 93 to maximize the strength of the connection between the first plate member 85 and the second plate member 86.
In one example, it is believed that for a first plate member 85 and a second plate member 86 having approximate dimensions of 200 mm by 300 mm and with the passages depicted in
If desired, the number of micro reservoirs 93 within each abutting region 91 may be set so at to provide a uniform density of micro reservoirs within each abutting region 91. However, in some instances, the gap between the first plate member 85 and the second plate member 86 may not be uniform throughout each of the abutting regions 91. Referring to
In still another embodiment, the brazing foil 92 may be combined with the use of micro reservoirs 93. For example, in the case of a second gap 97 being larger than the first gap 96 depicted in
Although described in the context of a hydraulic valve assembly 30 and valve body 32, the principles disclosed herein are equally applicable to any assembly in which two members are joined by brazing. The flexibility of utilizing non-uniform densities of micro reservoirs 93 or micro reservoirs in combination with brazing foil 92 or a layer of brazing material may be particularly useful in a number of situations. For example, the shape of the abutting surfaces may make a non-uniform distribution of brazing material desirable. In another example, some components may be relatively difficult to clamp together or may be substantially inflexible so as to create a non-uniform gap between the components when clamped together or when heated to a brazing temperature. In each of these examples, a non-uniform application of brazing material may be useful to create a desired joint of brazing material.
Referring to
At stage 113, the first plate member 85 and the second plate member 86 are aligned and positioned so that the first abutting surface 87 and the second abutting surface 88 are aligned a predetermined distance apart. At stage 114, the first plate member 85 and the second plate member 86 may be fixedly secured within an appropriate alignment fixture (not shown), clamped or otherwise secured to maintain the desired alignment and spacing between the first plate member 85 and the second plate member 86. The assembled first plate member 85 and the second plate member 86 may be processed at stage 115 through an appropriate furnace brazing operation so as to create a reliable joint along the connection plane 89 to join the first plate member 85 and the second plate member 86 and seal the edges of the passages to permit fluid to flow therethrough. It may be desirable to orient the first plate member 85, the second plate member 86 and their associated micro reservoirs 93 and the layer of brazing material so that the effects of gravity operate in a beneficial manner. For example, micro reservoirs 93 and the layer of brazing material may be applied to first abutting surface 87 and the first plate member 85 positioned on top of the second plate member 86 during the furnace brazing operation.
After the first plate member 85 and the second plate member 86 are brazed together to form valve body 32, additional machining operations may occur at stage 116. Various components such as the first spool bore actuator 71, the second spool bore actuator 72, the central shaft 73, the first lock valve assembly 75, the second lock valve assembly 76, the additional spool 77, the first solenoid 81, the second solenoid 82 and the compensator 83 may be mounted within and on the valve body 32 at stage 117 to assemble the hydraulic valve assembly 30.
In an alternate process, the first plate member 85 and the second plate member 86 may be slidably mounted so as to permit the first plate member and the second plate member to move closer to each other during the furnace brazing operation. That is, the first plate member 85 and the second plate member 86 may be spaced a first distance apart but may slide relative to each other during the furnace brazing operation to move closer together and reduce the distance between the two plate members.
The industrial applicability of the assembly described herein will be readily appreciated from the foregoing discussion. The foregoing discussion is applicable to assemblies that are formed from two or more plate members that are brazed together. In one example, the assembly may be formed of two plate members that are substantially inflexible and may have a gap between the plate members with a non-uniform thickness. The structure described herein permits a reliable brazing joint even with a non-uniform gap between the plate members. In other another example, a valve body 32 has passages through which hydraulic fluid may flow under high pressure. By forming the valve body 32 from a first plate member 85 and a second plate member 86, the passages within the plate members may be more easily and/or accurately formed. In addition, such a multi-component configuration may permit passages to be formed with shapes that permit more efficient fluid flow through the hydraulic valve assembly 30 and may permit passages to be formed with shapes that cannot be formed or may be more difficult to form with a one-piece valve body. In other words, forming the passages along the first and second abutting surfaces may provide additional flexibility with respect to the shapes of passages within valve body 32. Such access may be utilized to form more complex passages or more efficient passages to reduce pressure drop within the valve body 32.
In one aspect, the assembly includes a first plate member 85 with a first abutting surface 87 and a second plate member with a second abutting surface 88. One of the first abutting surface 87 and the second abutting surface 88 has a plurality of micro reservoirs 93 for storing brazing material prior to a process for joining the first abutting surface 87 and second abutting surface 88. The first abutting surface 87 and the second abutting surface 88 are positioned adjacent each other and are joined by the brazing material.
In another aspect, a method of forming an assembly includes providing a first plate member 85 with a generally planar first abutting surface 87. The first abutting surface 87 has a plurality of micro reservoirs 93. Brazing material is inserted into the micro reservoirs 93. A second plate member 86 with a generally planar second abutting surface 88 is provided. The first plate member 85 and second plate member 86 are positioned with the first abutting surface adjacent the second abutting surface. A brazing material is provided between the first plate member 85 and the second plate member 86. The first plate member 85, the second plate member 86, the brazing layer and the brazing material are heated to braze the first plate member to the second plate member.
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
