MAKING CLUTCH SYSTEMS SMARTER.
Microprocessor controller on new PT Tech HPTO clutch line designed to provide longer service life in applications with high inertia loads; "brains and brawn"While many components undergo their share of abuse in off-highway equipment, few face a tougher life than PTO clutches in machines such as grinders or crushers. As part of their normal duty cycle, manually or lever-operated PTO's are frequently subjected to extremely difficult, and at times abusive, operating conditions, particularly at engagement. And in the real world, machine operators have been known to contribute to the problem. In this situation, clutch service life is often foreshortened, resulting in warranty headaches for OEMs.
PT Tech has developed a new hydraulically actuated wet clutch for diesel-powered equipment designed to address the typical problems that can occur with manual clutches in heavy-duty applications. Available in two configurations for belt driven and direct-drive applications, the HPTO14 clutch is designed for heavy-duty applications between approximately 400 and 650 hp with operating speeds up to 2250 rpm. This covers a range of equipment such as tub grinders, rock crushers and roadworking equipment.
"Our whole approach is brains and brawn," said Ralph Rogers, vice president of the Sharon Center, Ohio, manufacturer. "A microprocessor provides brains. It regulates the clutch in such a manner to match the engine to the load and actually records what's happening."
"The brawn is inside the clutch, where we use the latest heavy-duty wet clutch technology. Oil is continually circulated throughout the unit, which provides the thermal capacity to handle the heat generated in these punishing applications. It's the first time electronics, hydraulics and mechanics have all come together for industrial clutches and we think it has a lot of advantages over traditional manual clutches and fluid couplings."
In development and testing for three years, the HPTO14 clutch is designed to mount directly to an SAE No. I flywheel. The clutch is unusual, Rogers said, in that it operates at low pressure and incorporates a disc pack made up of large diameter discs that are cooled by continuously circulating oil. This allows the clutch to absorb shock loads without damaging the disc pack. "If the hammermill on a grinder gets jammed, the clutch slips momentarily and acts as a shock absorber," said Rogers. "That's a common occurrence and it prevents a lot of damage."
The same oil that cools the clutch is used to continuously lubricate the bearings, thus eliminating the need for the operator to grease the bearings. Also, the clutch does not have a pilot bearing, which has long been a problem on manual clutches, Rogers noted.
Belt-drive configurations allow for high belt loads -- up to 11,500 lb. at 2000 rpm. This capability is accomplished without an outboard bearing.
The clutch also incorporates twin SAE six-bolt hydraulic pump drives located 17 in. apart from each other on either side of the main housing. The pump drives utilize Dana Chelsea mechanical power takeoffs. The pump drives are live regardless of clutch status, allowing hydraulics to be operated independent of the clutch. The pump drives can provide over 60 hp each, operating at 2250 rpm.
The microprocessor controller is designed for remote mounting. At the push of a button, it begins a controlled start-up sequence designed to bring high inertia loads up to speed without stalling the engine. "It's a pulsing action," Rogers explained. "In order to get the load going, it will hydraulically cycle the clutch on and off very quickly with the microprocessor monitoring the whole sequence.
"The monitoring and logging functions are very important," he added. Diagnostic information is displayed on an LCD text screen that is integral to the microprocessor. "It will tell you if there's a problem like a clogged filter. You're also able to get duty-cycle information that was never before really available. This information can be downloaded for duty-cycle review or field service analysis."
When the clutch is disengaged an internal brake is applied. "It's essentially a safety feature," Rogers said. "On a grinder for example the brake prevents the hammermill from slowly turning due to viscous drag in the disengaged clutch. Additionally, it reduces hammermill spin-down time when the clutch is disengaged."
The HPTO14 clutch is modular in design for simple service and repair. By disconnecting 10 bolts, the entire shaft/disc pack subassembly can be removed. While the basic package incorporates the clutch, microprocessor and hydraulic manifold, PT Tech can also supply a complete system that includes a hydraulic gear pump, oil cooler, filter, and reservoir.
The new clutches have gone into production and are built at PT Tech's 22,000 sq.ft. facility in Sharon Center, Ohio.
 Printer friendly
 Cite/link
 Email
 Feedback
| |
| Title Annotation: | PT Tech HPTO clutch line |
|---|---|
| Comment: | MAKING CLUTCH SYSTEMS SMARTER.(PT Tech HPTO clutch line) |
| Author: | Brezonick, Mike |
| Publication: | Diesel Progress North American Edition |
| Article Type: | Brief Article |
| Geographic Code: | 1USA |
| Date: | Jun 1, 2001 |
| Words: | 769 |
| Previous Article: | New Structure For Terex. |
| Next Article: | Newsmakers. |
| Topics: | |