Abstract
Cam-roller mechanisms convert rotary motion into translating or oscillating motion and are used in systems ranging from small-scale valvetrains and diesel injection systems to large-scale hydraulic pumps for offshore wind power generation. These highly dynamic mechanisms face varying loads and rapid speed changes, making the cam-roller interface a critical lubricated contact prone to surface damage. This research work focuses on studying and optimizing the cam-roller follower contacts in a novel large-scale hydraulic pump for offshore wind turbines, following a systematic approach divided into three phases: Understanding, Replicating, and Improving.
In Phase One (Understanding), outlined in Chapter 3, a modeling framework is developed to assess the rolling-sliding performance of radial and offset roller followers in a large-scale pump. The offset follower configuration is proposed to reduce tangential side thrust and enhance the lifespan of roller runner guides. This phase includes a comprehensive kinematic and force analysis, along with lubrication and frictional analyses of the cam-roller contact and internal spherical roller bearings. Insights into roller slippage, traction forces, roller inertia, and frictional torque are provided, forming a foundation for the subsequent phases.
Phase Two (Replicating), detailed in Chapters 4 and 5, involves the design and development of a small-scale experimental test setup to replicate the rolling-sliding dynamics of large-scale cam-roller contacts. Chapter 4 introduces the test setup and an experimental method based on torque control for steady-state conditions. In Chapter 5, the test setup is upgraded for dynamic testing, which is crucial for validating the modeling framework and the improvements proposed in Phase Three.
Phase Three (Improving), presented in Chapter 6, introduces an innovative rolling pair concept to minimize slippage. This concept's validation uses the experimental techniques and test setup described in Phase Two.
Key findings include a 51% reduction in side thrust with the offset follower configuration and insights into load-dependent rolling-sliding dynamics. The custom-built test setup effectively replicates large-scale dynamics, revealing that small torque increases significantly affect slide-to-roll ratios at low loads. The novel rolling pair design significantly reduces slippage and undesirable dynamic effects, demonstrating its applicability in hydraulic pumps for offshore wind turbines.
In Phase One (Understanding), outlined in Chapter 3, a modeling framework is developed to assess the rolling-sliding performance of radial and offset roller followers in a large-scale pump. The offset follower configuration is proposed to reduce tangential side thrust and enhance the lifespan of roller runner guides. This phase includes a comprehensive kinematic and force analysis, along with lubrication and frictional analyses of the cam-roller contact and internal spherical roller bearings. Insights into roller slippage, traction forces, roller inertia, and frictional torque are provided, forming a foundation for the subsequent phases.
Phase Two (Replicating), detailed in Chapters 4 and 5, involves the design and development of a small-scale experimental test setup to replicate the rolling-sliding dynamics of large-scale cam-roller contacts. Chapter 4 introduces the test setup and an experimental method based on torque control for steady-state conditions. In Chapter 5, the test setup is upgraded for dynamic testing, which is crucial for validating the modeling framework and the improvements proposed in Phase Three.
Phase Three (Improving), presented in Chapter 6, introduces an innovative rolling pair concept to minimize slippage. This concept's validation uses the experimental techniques and test setup described in Phase Two.
Key findings include a 51% reduction in side thrust with the offset follower configuration and insights into load-dependent rolling-sliding dynamics. The custom-built test setup effectively replicates large-scale dynamics, revealing that small torque increases significantly affect slide-to-roll ratios at low loads. The novel rolling pair design significantly reduces slippage and undesirable dynamic effects, demonstrating its applicability in hydraulic pumps for offshore wind turbines.
Original language | English |
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Qualification | Doctor of Philosophy |
Awarding Institution |
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Supervisors/Advisors |
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Award date | 5 Jun 2024 |
Place of Publication | Enschede |
Publisher | |
Print ISBNs | 978-90-365-6110-5 |
Electronic ISBNs | 978-90-365-6111-2 |
DOIs | |
Publication status | Published - 5 Jun 2024 |