Patent Application
20180074467
Engine rebuilding has become a popular alternative to purchasing new engines in such fields as automobiles and watercraft. In some high performance industries such as professional racing, teams build and rebuild their engines before every racing event. To the average consumer and the racing professional alike, accurate machining and rebuilding is a necessity for good performance and reliability of an engine. Resurfacing cylinder heads and engine blocks is an essential aspect of engine building/rebuilding today, whether the work is being done by a production engine rebuilder, a high performance specialist or small custom shop.
Common types of machines used for rebuilding parts of an engine include computer numerical controlled (CNC) machines. These machines can be configured to carry out one or more machining or resurfacing operations, including polishing, boring, honing, reaming, drilling, etc., and are commercially available from Rottler Manufacturing and Sunnen, among others.
In accordance with an embodiment of the present disclosure, a computer implemented method is provided for resurfacing at least one surface of a workpiece. The method includes moving a cutting tool with respect to a surface to be resurfaced; and while moving the cutting tool with respect to said surface to be resurfaced, rotating the cutting tool in a repeating cycle comprising alternating acceleration and deceleration stages.
In accordance with another embodiment of the present disclosure, an apparatus is provided. The apparatus includes a spindle carrying a resurfacing tool, an electric motor operatively connected to the spindle and configured to rotate the spindle about an axis, and a control system configured to control the operation of the motor in order to rotate the spindle through a repeating acceleration and deceleration cycle during a resurfacing operation.
In accordance with another embodiment of the present disclosure, a computer readable medium carrying instructions thereon that carry out actions including a vibration reduction operation in which a spindle is cycled between acceleration and deceleration as the spindle is rotated during a resurfacing process.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
The foregoing aspects and many of the attendant advantages of the disclosed subject matter will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
The detailed description set forth below in connection with the appended drawings where like numerals reference like elements is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result.
The following description sets forth examples of systems and methods for reducing vibration in a computer controlled machining apparatus, such as a seat and guide resurfacing machine. In the following description, numerous specific details are set forth in order to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that many embodiments of the present disclosure may be practiced without some or all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein.
Although some embodiments of the present disclosure will be described hereinafter with reference to resurfacing a seat and/or guide of an engine cylinder head, it will be appreciated that aspects of the present disclosure have wide application, and therefore, may be suitable for use with many types of machining or resurfacing operations, including polishing, honing, boring, reaming, drilling, etc. Accordingly, the following descriptions and illustrations herein should be considered illustrative in nature, and thus, not limiting the scope of the claimed subject matter.
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In one embodiment, the work table 24 is movable in a substantially horizontal plane (e.g., XY plane) for generally aligning the workpiece with a machine spindle system that will be described in more detail below. In one embodiment, the fixation device can include an adjustable trunnion assembly. The adjustable trunnion assembly may include clamps to hold down the workpiece and an axis aligning control mechanism that permits fine position adjustment of the workpiece. The aligning control mechanism may rotate the workpiece about vertical and horizontal axes. Other movement for permitting fine adjustment may be accomplished by the trunnion assembly, if desired.
The machining apparatus 20 also includes a tool support 32, which carries a machine spindle system 34. In some embodiments, the tool support 32 is mounted for reciprocating movement via a linear stage 36 oriented in the X-direction (horizontal direction). The linear stage 36 comprises, for example, a linear slide type bearing interface to restrict motion of the tool support 32 in only the X-direction, and a linear drive system for providing reciprocating motion to the tool support 32. In one embodiment, the linear drive system includes, for example, a conventional ball screw mechanism (hidden in
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In one embodiment, the machine tool 60 includes an upper, driver section and a lower, tool holder section. In one embodiment, the driver section includes a spindle shaft section. The spindle shaft section in some embodiments is formed with a quick change male taper that may be removably coupled in a rotationally driven manner through a cooperatively configured, one handed automatic tightening spindle lock nut system (hereinafter “lock nut system”) associated with the interface 66. Lock nut systems that may be practiced with embodiments of the present disclosure are described in U.S. Pat. Nos. 7,726,919 and 3,829,109, both of which are hereby expressly incorporated by reference. It will be further appreciated that the machine tool/spindle can incorporate a spherical joint and pilot arrangement of the type known in the industry as the UNIPILOT™, sold with select SG™ series machining stations or sold separately therefrom and available from Rottler Manufacturing, Kent, Wash.
In operation, once inserted into a suitable portion of a work piece 28, such as a seat of a cylinder head, the tool 60 can be rotated, as denoted by arrow C, via the spindle 64 under control of the control system 100 for resurfacing, e.g., cutting, a surface 30 of a work piece 28. In a typical application, as spindle carriage 54 is reciprocally stroked upwardly and downwardly, as denoted by arrow A, the tool 60 will rotate in one direction or the other, as denoted by arrow C, within a hole, seat, etc., of a workpiece, for providing a desired size, surface finish and/or shape to one or more surfaces of such a hole, seat, guide, etc.
Other linear drive systems can be practiced with embodiments of the present disclosure, including drive motor actuated cam linkage mechanisms, roller screws, rack and pinion, hydraulic or pneumatic cylinders, chain or belt drives, etc. For example, any of the ball screw mechanisms described herein could be substituted with other means of rotary to linear motion conversion (e.g., rack & pinion, etc.,) or that the motor, encoder/sensor and ball screw together could be substituted with a linear motor and linear encoder, or any other system of providing precise position controlled linear motion.
In some embodiments, examples of machining apparatus that may be practiced with or carry out methods of embodiments of the present disclosure include, but are not limited to, the SG™ series of machining stations available from Rottler Manufacturing, Kent, Wash.
As briefly described above, the drive motors 80 and 88, and spindle motor 92 are operated under the control of a control system 100.
One example of the one or more computing devices 102 will now be described in more detail. In some embodiments, the one or more computing devices 102 either separately or in combination may include at least one processor 106 or central processing unit (CPU), a memory 108, and I/O circuitry 112 suitably interconnected via one or more buses. Depending on the exact configuration and type of device, the memory 108 may include system memory in the form of volatile or nonvolatile memory, such as read only memory (“ROM”), random access memory (“RAM”), EEPROM, flash memory, or similar memory technology. The system memory is capable of storing one or more programs, that are immediately accessible to and/or currently being operated on by the CPU. In this regard, the CPU serves as a computational center of the computer 100 by supporting the execution of instructions.
The memory 108 may also include storage memory, and may include a data store 116. The storage memory may be any volatile or nonvolatile, removable or nonremovable memory, implemented using any technology capable of storing information. Examples of storage memory include but are not limited to a hard drive, solid state drive, CD ROM, DVD, or other disk storage, magnetic cassettes, magnetic tape, magnetic disk storage, and the like. The information stored in the storage memory to be accessed by the CPU includes but is not limited to program modules, such as an operating system (Microsoft Corporation's WINDOWS®, LINUX, Apple's Leopard, etc.), and one or more CNC and/or CAM modules for carrying out one or more machining operations of the apparatus. Generally, program modules or “engines” may include routines, applications, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. In some embodiments, the one or more CNC machining modules are configured to operate the apparatus based, in part, on obtained data (e.g., inputted from user, access from operational history, etc.) in order to carry out one or more machining operations (e.g., boring, honing, reaming, milling, porting, etc.). The memory 108 also stores one or more variable spindle speed and/or vibration reduction modules, routines, etc.
As used herein, the term processor is not limited to integrated circuits referred to in the art as a computer, but broadly refers to a microcontroller, a microcomputer, a microprocessor, a programmable logic controller, an application specific integrated circuit, other programmable circuits, combinations of the above, among others. In one embodiment, the processor 104 executes instructions stored in memory 108, such as CNC machining instructions, CAM instructions, etc.
The modules or “engines” stored in memory 108 as well as other modules associated with the control system 100 may include one or more sets of control algorithms, determination algorithms, numerical control instructions, etc., including resident program instructions and calibrations stored in one of the storage mediums and executed to provide desired functions. Information transfer to and from the modules can be accomplished by way of a direct connection, a local area network bus and a serial peripheral interface bus.
The algorithms may be executed during preset loop cycles such that each algorithm is executed at least once each loop cycle. Algorithms stored in the non-volatile memory devices are executed by the processor to monitor inputs from the sensing devices, such as sensors 94, 96, 98, etc., and other data transmitting devices or polls such devices for data to be used therein. Loop cycles are executed at regular intervals, for example each 3.125, 6.25, 12.5, 25 and 100 milliseconds during ongoing operation of the apparatus. Alternatively, algorithms may be executed in response to the occurrence of an event.
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The one or more computing devices 102 may also interface with one or more output devices 120 in the form of graphical display 74 (e.g., liquid crystal display (LCD), light emitting polymer display (LPD), plasma display, Light emitting Diode (LED) display, Organic Light emitting Diode (OLED) display, etc.). The one or more computing devices 102 may also include one or more input devices 122, such as a keyboard, touch pad, joystick, cameras, a pointing device, among others. In one embodiment, the display 74 can also be configured as a touchscreen for inputting data. The output devices 120 and input devices 122 can also be referred to as HMI devices herein. The output devices and the input devices are suitably connected through appropriate interfaces of the I/O circuitry. As would be generally understood, other input/output devices may also be connected to the processor in a similar manner.
In one embodiment, as depicted in the graph of
In some embodiments, the acceleration and declaration times are identical. In one embodiment, the acceleration time and the deceleration time is 40 milliseconds. In other embodiments, the acceleration and declaration times are different. In some embodiments, the spindle is accelerated with a constant acceleration. In other embodiments, the spindle is accelerated with a non-constant or varying acceleration. In some embodiments, the spindle is decelerated with a constant deceleration. In other embodiments, the spindle is decelerated with a non-constant or varying deceleration. In some embodiments, dwell times, designated at 520 and 524 at the LOW RPM and HIGH RPM, respectively, are 5 milliseconds.
In accordance with an aspect of the present disclosure, the spindle speed (constant) or speeds (variable) can change during the cutting operation of the cutting tool under control of the control system. For example, a cutting operation of, for example, a valve seat, may involve two stages, a rough or start cut stage in which the spindle moves in a first direction along the Z-axis to a predetermined position (e.g., finish depth) and a finish cut stage in which the spindle moves in a direction opposite the first direction along the Z-axis to return to its start position. In some embodiments, the spindle speed during the rough cut stage is faster than the spindle speed during a finish cut stage or vice versa.
In some cutting operations, the cutting tool can make multiple passes into, out of, or through the object to be resurfaced. The spindle speed of each subsequent pass in some of these embodiments may be faster than the previous pass. In other of these embodiments, the spindle speed of each subsequent pass may be slower than the previous pass. The spindle during each pass, stage, etc., may be operated with a variable speed as described above, while in other embodiments, the spindle may be operated during one or more stages or passes of a set of stages or passes with a variable speed while the spindle is operated during the remaining stages or passes of the set of stages or passes with a constant speed. In some embodiments, at least the finish cut stage or final pass of the spindle is operated via implementation of the one of the various embodiments of the with variable spindle speed program module discussed above.
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The present disclosure may include references to directions, such as “upper,” “lower,” “upward,” “downward,” “top,” “bottom,” “first,” “second,” etc. These references and other similar references in the present disclosure are only to assist in helping describe and understand the exemplary embodiments and are not intended to limit the claimed subject matter to these directions.
The present disclosure may also reference quantities and numbers. Unless specifically stated, such quantities and numbers are not to be considered restrictive, but exemplary of the possible quantities or numbers associated with the present disclosure. Also in this regard, the present disclosure may use the term “plurality” to reference a quantity or number. In this regard, the term “plurality” is meant to be any number that is more than one, for example, two, three, four, five, etc. The terms “substantially,” “about,” “approximately,” etc., mean plus or minus 5% of the stated value.
The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure which are intended to be protected are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the present disclosure.
This application claims the benefit of U.S. Provisional Application No. 62/394651, filed on Sep. 14, 2016, the disclosure of which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62394651 | Sep 2016 | US |
