Patent Application
20070153414
This invention relates to hard disk drive components, in particular, to mechanisms to regulate and control the internal ambient temperature inside a hard disk drive.
Contemporary hard disk drives are faced with severe challenges. They must operate wherever their users decide to operate them, in environments where the hard disk drive must operate outside of room temperature.
When a hard disk drive is too hot, many operating problems develop. Heat tends to decay the material of the rotating disk surfaces on which the data is stored. The mechanical component tolerances degrade due to differences in their coefficients of thermal expansion. The pressure at the air bearing surface will change due to the high temperature. The breakdown of lubricants used in the hard disk drive is accelerated. The sensitivities due to thermal asperities during read operations is increased. The effects of thermal pole tip protrusion are maximized.
When the hard disk drive is too cold, other operating problems develop. The thermal coercivity of the disk media is lowered, degrading the ability to write data to tracks on the disk surfaces. The pressure at the air bearing surface will change due to the low temperature. It takes longer to start up the hard disk drive when it is cold, due to the viscosity of the lubricant in the spindle motor. The effects of thermal pole tip protrusion are minimized.
Today, many hard disk drives include some device measuring the internal temperature, and in some situations, the operating parameters of the hard disk drive are altered based upon the measured internal temperature. In many hard disk drives, at least part of the exterior face of the disk base is configured as a primitive thermal transfer element. However, no hard disk drives are known to be able to adjust their internal temperature. What is needed is a hard disk drive able to adjust its internal temperature toward its optimal operating temperature range.
Definitions: Heat transfer interface as used herein means any passageway for heat transfer. Thermal-couple as used herein refers to a layer of material between adjacent transfer interfaces which assists the transfer of heat between the transfer interfaces; typically but not necessarily an adhesive material. Thermal-coupling as used herein describes the action of providing a passageway for heat transfer.
The invention includes an external cover for a hard disk drive containing an internal thermal zone. The external cover includes an internal heat transfer interface which is capable of transferring heat to a thermoelectric device in thermal contact therewith. In some embodiments there is a thermal-coupling between the interior heat transfer interface and the thermoelectric device. In some embodiments the interior heat transfer interface is adhered to the thermoelectric device using an adhesive thermal-coupling. A disk cover and/or a disk base may serve as the external cover for the hard disk drive. The thermoelectric device may preferably provide heat transfers across the internal transfer interface, into the internal thermal zone to warm it, and out of the internal thermal zone to cool it.
The internal thermal zone may preferably include at least one disk surface, and may preferably further include all the disk surfaces and sliders moving near the disk surfaces.
In some embodiments, the internal heat transfer interface may provide a nearly planar surface to the thermoelectric device. In some preferred embodiments, the planar surface may have a surface area of at least one square inch, and at most four square inches.
The external cover may further include the thermoelectric device providing an exterior heat transfer interface external thermal-coupling to the exterior of the hard disk drive. The thermoelectric device may include an intermediate heat transfer interface thermal-coupling to the disk drive transfer interface. The external thermal-coupling may further preferably be to air exterior to the hard disk drive.
The thermoelectric device may preferably include an electrical contact pair providing enabling power for a first heat transfer from the interior transfer interface to the exterior heat transfer interface to cool the disk drive, and a second heat transfer from the exterior heat transfer interface to the interior heat transfer interface. Preferably, applying a first potential difference between the electrical contact pair enables the first heat transfer, and applying a second potential difference between the electrical contact pair enables the second heat transfer. Preferably, the sign of the first potential difference is opposite the sign of the second potential difference.
The external cover may further include a thermal controller receiving a temperature measure of the internal thermal zone and providing a driving signal to the first electrical contact pair. Preferably, the thermal controller forces the driving signal toward the first potential difference when the temperature measure is greater than a top operating temperature. Preferably, the thermal controller forces the driving signal toward the second potential difference, when the temperature measure is less than a lower operating temperature. The controller may also receive a signal from the drive firmware to enable or disable.
The thermal controller may include at least one of the following. A finite state machine generating a digital version of the driving signal based upon the temperature measure. A computer accessibly coupled to a memory containing a program system including at least one program step generating a second digital version of the driving signal based upon the temperature measure. A neural network responding to the temperature measure to generate a third digital version of the driving signal. The thermal controller may further include exactly one of the finite state machine, the computer and the neural network.
The program system may include a program step implementing the neural network responding to the temperature measure to generate the third digital version of the driving signal.
The thermal controller may include an analog circuit generating the driving signal based upon at least one of the temperature measure, the digital version of the driving signal, the second digital version of the driving signal, and the third digital version of the driving signal. The analog circuit may further generate the driving signal based upon exactly one of these.
The external cover may further include a second electrical contact pair driving a fan motor powering a fan to move air across a thermal transfer element exterior to the hard disk drive. The thermal controller may further provide a fan driving signal to the second electrical contact pair. The thermal controller may preferably provide the fan driving signal with at least one fan potential difference distinct from zero volts, when the temperature measure is either greater than the top operating temperature or less than the bottom operating temperature. The fan driving signal may be at least temporarily a Direct Current (DC) signal and/or an Alternating Current (AC) signal.
The thermoelectric device includes at least one semiconductor device acting as a heat pump and using the internal heat transfer interface to thermally-affect the internal thermal zone. The thermoelectric device may use the internal heat transfer interface to move heat out of the internal thermal zone, which will tend to thermally-affect the internal thermal zone by lowering its temperature. Also, the thermoelectric device may use the internal heat transfer interface to move heat into the internal thermal zone, tending to thermally-affect the internal thermal zone by raising its temperature.
Manufacture of the external cover may include at least one of the following. Die-stamping a sheet of metal to at least partly create the external cover including the interior heat transfer interface. Molding molten metal to at least partly create the external cover including the interior heat transfer interface. The sheet of metal may preferably include a form of sheet stainless steel. The molten metal may include a form of molten aluminum. The invention includes the external cover as a product of this process.
The external cover operates as follows. The thermoelectric device enables a first heat transfer from the internal thermal zone via the internal heat transfer interface to the exterior of the hard disk drive, and enables a second heat transfer from the exterior of the hard disk drive via the internal heat transfer interface to the internal thermal zone. A driving signal may preferably be provided to the electrical contact pair coupling to the thermoelectric device to enable the first heat transfer, the second heat transfer, or essentially no-heat transfer. The driving signal may act as a direct current (DC) signal.
A temperature measure may preferably be determined for the internal thermal zone. Forcing the driving signal toward the first potential difference may preferably occur when the temperature measure is greater than a top operating temperature. Forcing the driving signal toward the second potential difference may preferably occur when the temperature measure is less than the bottom operating temperature.
Pulse-width-modulation may be employed. Forcing the driving signal toward the first potential difference may preferably include pulse-width-modulating the driving signal between the first potential difference and zero volts, preferably based upon the temperature measure. Forcing the driving signal toward the second potential difference may preferably include pulse-width-modulating the driving signal between the second potential difference and zero volts, preferably based upon the temperature measure.
The invention includes the hard disk drive, containing the external cover providing the internal heat transfer interface. The hard disk drive may further include the thermoelectric device thermal-coupled to the internal heat transfer interface and to an exterior heat transfer interface for heat transfers with an exterior of the hard disk drive.
The invention includes systems using at least one of the hard disk drives, which include a thermal conduit to the hard disk drive. These systems include, but are not limited to, a Redundant Arrays of Inexpensive Disks (RAID), a server computer, a desktop computer, and a notebook computer.
The invention includes manufacturing the hard disk drive, which includes at least one of the following. Using a disk cover as the external cover to create the hard disk drive. Using a disk base as the external cover to create the hard disk drive. The manufacturing may include using both the disk cover and the disk base as external covers for the hard disk drive.
The invention includes the hard disk drive as a product of the manufacturing process. The hard disk drive with both its disk base and disk cover as external covers, each possessing heat transfer interfaces may be preferred in systems supporting multiple hard disk drives, such as a RAID, because adjacent pairs of hard disk drives may share a thermal conduit.
FIGS. 1 to 3 shows the invention moving heat into and out of an internal thermal zone of the hard disk drive;
FIGS. 5 to 8C show various aspects of the external cover with the transfer interface of FIGS. 1 to 3 with regards to the hard disk drive;
This invention relates to hard disk drive components, in particular, to mechanisms to regulate and control the internal ambient temperature inside a hard disk drive.
The invention includes an external cover 100 for a hard disk drive 10 containing an internal thermal zone 20. The external cover includes an internal heat transfer interface 110 thermal-coupling to the internal thermal zone and to a thermoelectric device 200 as shown in FIGS. 1 to 3 through thermal-couple 112. A disk cover 16 and/or a disk base 14 may serve as the external cover for the hard disk drive as shown in FIGS. 5 to 7C.
The thermoelectric device 200 may preferably provide two heat transfers across the internal heat transfer interface 110 to the exterior 300 of the hard disk drive 10, into the internal thermal zone 20 to warm it, and out of the internal thermal zone to cool it, as shown in
The internal thermal zone 20 may preferably include at least one disk surface 12-1, and may preferably further include each disk 12, each disk surface 12-1 and each slider 90 moving near the disk surfaces as shown in
The internal heat transfer interface 110 may provide a nearly planar surface to the thermoelectric device 200, as shown in FIGS. 1 to 3, and 5 to 7B. The planar surface may have a surface area of at least one square inch. The surface area may further be at most four square inches.
The external cover 100 may further include the thermoelectric device 200 providing an exterior heat transfer interface 132 thermal-coupling to the exterior 300 of the hard disk drive 10 through thermal-couple 134. The thermoelectric device may include a intermediate heat transfer interface 130 in the thermal contact through thermal-coupling 112 to the intermediate transfer interface 110. The external thermal-coupling may further preferably be to air 150 exterior 300 to the hard disk drive 10.
The thermoelectric device 200 may preferably include an electrical contact pair 210 providing enabling power for a first heat transfer 120 from the internal heat transfer interface 110 to the exterior heat transfer interface 132, and a second heat transfer 132 from the exterior heat transfer interface to the transfer interface. Preferably, applying a first potential difference V1 between the electrical contact pair 210 enables the first heat transfer as shown in
The thermoelectric device 200 includes at least one semiconductor device acting as a heat pump and using the internal heat transfer interface 110 to thermally-affect the internal thermal zone 20, as shown in FIGS. 1 to 3. The thermoelectric device may use the transfer interface to move heat out of the internal thermal zone, which will tend to thermally-affect the internal thermal zone by lowering its temperature, as shown in
A thermoelectric device 200 refers herein to a solid-state heat pump that may preferably operate on the Peltier effect. The thermoelectric device contains an array of p- and n-type semiconductor elements heavily doped with electrical carriers. This array is often electrically connected in series and thermally connected in parallel and then affixed to two ceramic substrates, the intermediate heat transfer interface 130 and the exterior heat transfer interface 132, one on each side of the elements, as in FIGS. 1 to 3.
Consider how the heat transfer occurs as electrons flow through one pair of n- and p-type elements, which is referred to herein as a couple within the thermoelectric device. Electrons can travel freely in the conductors, which are often made of copper, but not so freely in the semiconductor. These conductors are labeled Cu in FIGS. 1 to 3. This discussion will now focus on
As the electrons leave the conductor Cu, they enter the hot side of the P-Type and must fill a hole in order to move through the P-Type. When an electron fills a hole, it drops to a lower energy level, releasing heat. The holes in the P-Type move from the cold side to the hot side. As an electron moves from the P-Type into the conductor Cu on the cold side, the electron moves to a higher energy level through absorbing heat. The electron moves freely through the conductor CU until reaching the cold side of the N-Type semiconductor. When the electron moves into the N-Type, it bumps up an energy level in order to move through the semiconductor, absorbing heat. As the electron leaves the hot-side of the N-Type, it moves freely in the conductor Cu. It drops to a lower energy level releasing heat.
Heat is always absorbed at the cold side of the n- and p-type elements. The electrical charge carriers (holes in the P-Type; electrons in the N-Type) always travel from the cold side to the hot side, and heat is always released at the hot side of a thermoelectric element. The heat pumping capacity of a thermoelectric device is proportional to the current and dependent on the element geometry, number of couples, and material properties.
As used herein, the Peltier effect is the phenomenon whereby the passage of an electrical current through a junction consisting of two dissimilar metals results in a cooling effect. When the direction of current flow is reversed heating will occur.
A thermal transfer element 230 refers herein a device that is typically attached to a heat transfer interface of a thermoelectric device 200, usually the exterior heat transfer interface 132, for heat transfers with the exterior 300 of the hard disk drive 10. It is used to facilitate the transfer of heat between the thermoelectric device and the exterior of the hard disk drive. The most common thermal transfer element is an aluminum plate that has fins attached to it, as shown in FIGS. 1 to 3, 7C and 8C. A fan 222 is used to move ambient air 150 through the thermal transfer element to transfer heat. Another style of thermal transfer element uses a plate with tubing embedded in it. A liquid is sent through the tubing to pick up heat from the thermoelectric device.
The external cover 100 may further include a thermal controller 500 receiving a temperature measure 510 of the internal thermal zone 20 and providing a driving signal 160 to the electrical contact pair 210, as shown in
The thermal controller 500 may include at least one of the following. A finite state machine 502 generating a digital version of the driving signal 504 based upon the temperature measure 510 as in
As used herein, the computer 520 will include at least one instruction processor and at least one data processor. Each data processor will be directed by at least one instruction processor. The computer may be implemented in, or as, a Field Programmable Gate Array, gate array, an application specific integrated circuit, a digital signal processor, and/or a general-purpose microprocessor.
The memory 524 may include memory components that are non-volatile memories and/or volatile memories. Non-volatile memories tend to retain their memory contents without the application of external power, whereas volatile memories tend to lose their memory contents without the application of external power. The memory may and often does contain both non-volatile memory components and volatile memory components.
The finite state machine 502 may be implemented by any combination of: a logic circuit, a programmable logic device, and/or a Field Programmable Gate Array. The logic circuit may be implemented in a gate array and/or an application specific integrated circuit.
The neural network 530 may be implemented similarly to the finite state machine 502, and include neurons, each with a neural state and coupling through weighted paths to other neurons. Upon the stimulus of the temperature measure 510, the neural network responds by calculating the path couplings, possibly changing the state of at least some of the neurons, and taking the weighted path response to generate the third digital version of the driving signal 534.
The following figures include flowcharts of at least one method of the invention possessing arrows with reference numbers. These arrows will signify of flow of control and sometimes data, supporting implementations including at least one program step or program thread executing upon a computer, inferential links in an inferential engine, state transitions in a finite state machine, and learned responses within a neural network.
The step of starting a flowchart refers to at least one of the following and is denoted by an oval with the text “Start” in it. Entering a subroutine in a macro instruction sequence in a computer. Entering into a deeper node of an inferential graph. Directing a state transition in a finite state machine, possibly while pushing a return state. And triggering at least one neuron in a neural network.
The step of termination in a flowchart refers to at least one of the following and is denoted by an oval with the text “Exit” in it. The completion of those steps, which may result in a subroutine return, traversal of a higher node in an inferential graph, popping of a previously stored state in a finite state machine, return to dormancy of the firing neurons of the neural network.
A step in a flowchart refers to at least one of the following. The instruction processor responds to the step as a program step to control the data execution unit in at least partly implementing the step. The inferential engine responds to the step as nodes and transitions within an inferential graph based upon and modifying a inference database in at least partly implementing the step. The neural network responds to the step as stimulus in at least partly implementing the step. The finite state machine responds to the step as at least one member of a finite state collection comprising a state and a state transition, implementing at least part of the step.
Several flowcharts include multiple steps. In certain aspects, any one of the steps may be found in an embodiment of the invention. In other aspects, multiple steps are needed in an embodiment of the invention. When multiple steps are needed, these steps may be performed concurrently, sequentially and/or in a combination of concurrent and sequential operations. The shapes of the arrows in multiple step flowcharts may differ from one flowchart to another, and are not to be construed as having intrinsic meaning in interpreting the concurrency of the steps.
The program system 600 of
The program system 600 may include a program step implementing the neural network 530 responding 532 to the temperature measure 510 to generate the third digital version of the driving signal 534, as shown by operation 604 of
The thermal controller 500 may include an analog circuit 560 generating the driving signal 160 based upon at least one of the temperature measure 510, the digital version of the driving signal 504, the second digital version of the driving signal 526, and the third digital version of the driving signal 534 as shown in
The external cover 100 may further include a second electrical contact pair 212 driving a fan motor 220 powering a fan 222, as shown in
Manufacture of the external cover 100 may include at least one of the following. Die-stamping 700 a sheet of metal 702 to at least partly create the external cover including the transfer interface 110. Molding 710 molten metal 712 to at least partly create the external cover including the transfer interface. The sheet of metal may preferably include a form of sheet stainless steel. The molten metal may include a form of molten aluminum. The invention includes the external cover as a product of this process.
The manufacture of the external cover 100 may further include thermal-coupling a thermoelectric device 200 via the internal heat transfer interface 110 to its intermediate heat transfer interface 130. Such external covers are shown in FIGS. 1 to 3, and may be preferred for use in a system employing shared fans and fan motors. Further, a thermal transfer element 230 may be thermally-coupled to the exterior heat transfer interface 132. A fan motor 220 and fan 222 may further be positioned near the thermal transfer element 230, as shown in
The external cover 100 operates as follows. While these operations may be implemented in a variety of fashions, to simplify their discussion, they will be discussed as implemented through operations performed by the program system 600.
The thermoelectric device 200 enables a first heat transfer 120 from the internal thermal zone 20 via the internal heat transfer interface 110 to the exterior 300 of the hard disk drive 10 as shown in
A driving signal 160 may preferably be provided to the electrical contact pair 210 coupling to the thermoelectric device 200 to enable the first heat transfer 130 as in operation 620 of
Providing the driving signal 160 may preferably include forcing the driving signal toward the first potential difference V1 to enable the first heat transfer 120 as in operation 630 of
A temperature measure 510 may preferably be determined for the internal thermal zone 20. Forcing the driving signal 160 toward the first potential difference V1 may preferably occur when the temperature measure is greater than a top operating temperature 512 as in operation 640 of
Pulse-width-modulation may be employed. Forcing the driving signal 160 toward the first potential difference V1 may preferably include pulse-width-modulating the driving signal between the first potential difference and zero volts, preferably based upon the temperature measure 510, as in operation 650 of
The invention includes the hard disk drive 10, containing the external cover 100 providing the internal heat transfer interface 110 thermal-coupling to the internal thermal zone 20. The hard disk drive may further include the thermoelectric device 200 thermal-coupling to the transfer interface and to an exterior heat transfer interface 132 for heat transfers with an exterior 300 of the hard disk drive.
The invention includes a system 790 using at least one of the hard disk drive 10 as shown in
The invention includes manufacturing the hard disk drive 10, which includes at least one of the following. Using a disk cover 16 as the external cover 100 as shown in FIGS. 6 to 7C to create the hard disk drive. Using a disk base 14 as the external cover, as shown in
The invention includes the hard disk drive 10 as a product of the manufacturing process. The hard disk drive with both its disk base 14 and disk cover 16, each as an external cover 100, each possessing a transfer interface 10, may be preferred in a system 790 supporting multiple hard disk drives, such as a RAID 800, because adjacent pairs of hard disk drives may share a thermal conduit 310, as shown in
The preceding embodiments provide examples of the invention and are not meant to constrain the scope of the following claims.
