Drill Drive Device Spring Arrangement for Percussive Load Damping
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Solution Overview
Problem
Down-the-hole hammer drilling units impose additional load on rotary drill drives due to percussive movements, requiring axial support and play to maintain efficient drilling and protect the drill drive, especially when using drill rods with threaded connections.
Innovation Solution
A drill drive device with a combination of compression coil springs and disk spring arrangements provides a floating support between spindle units, absorbing and dampening percussive movements, allowing for efficient drilling and torque transmission while maintaining axial play for threaded connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-loaded support is provided for the drive spindle to protect against axial hammer blows, then the drill drive is protected from percussive loads, but the operation of the drive spindle is affected due to limited axial movement
Solution Approach 1:
The spring support system is divided into two separate spring means: a first spring means between the drilling tool and inner spindle unit, and a second spring means between the inner and outer spindle units. This segmentation allows each spring to be optimized for specific functions - the first spring handles tool connection and initial damping, while the second spring provides additional protection for the drive spindle without interfering with operational axial movement.
Solution Approach 2:
The invention combines multiple spring elements (compression coil spring and disk spring arrangement) within the first spring means to create a composite spring system. This merging provides both the necessary axial compliance for drilling operations and sufficient damping capacity to protect against percussive loads, resolving the contradiction between protection and operational freedom.
2Ease of manufacture
If axial play is provided for threaded connections of drill rods, then assembly of drill rod elements is enabled, but excessive axial movement may compromise drilling efficiency
Solution Approach 1:
The spring means are designed with specific mechanical properties (spring constants, pre-tensioning forces) that allow controlled axial compliance. The first disk spring arrangement provides sufficient axial play for threaded connections during assembly, while the pre-tensioning force maintains optimal contact between drilling tool and drill rod during drilling operations, thus maintaining drilling efficiency.
3Productivity
If a down-the-hole hammer unit is used for rock drilling, then efficient rock drilling is achieved, but additional percussive loads are imposed on the rotary drill drive
Solution Approach 1:
The spring means are positioned between the drilling tool and the drill drive to provide beforehand cushioning against percussive loads. The first spring means (with compression coil spring and disk spring arrangement) and the second spring means (disk spring arrangement) are pre-configured to absorb and dampen hammer blows before they reach the drill drive, protecting it from harmful percussive loads while allowing the down-the-hole hammer unit to operate efficiently.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively dampens percussive loads, ensuring efficient drilling operations and protecting the drill drive by absorbing and transmitting torque in a controlled manner, facilitating easy assembly and maintenance.
Implementation Method 1
a first front spring means which is arranged on a drilling tool side comprises a combination of at least a compression coil spring and a first disk spring arrangement
Implementation Method 2
percussive movements emanating from the drilling tool, especially a down-the-hole hammer unit, can be absorbed and dampened particularly well
Implementation Method 3
By preference, the torque is introduced via the outer spindle unit so that due to the absence of support impacts from the inner spindle unit cannot be transmitted or are only transmitted in a strongly dampened way to the outer spindle unit
Data Source
AI summary
The invention relates to a drill drive device (10) for an earth drilling apparatus with a spindle arrangement which has an inner spindle unit (20) and an outer spindle unit (40) that is supported in an axially displaceable manner on the inner spindle unit (20) and floating between two spring means (50, 60). According to the invention provision is made in that a first front spring means (50) which is arranged on a drilling tool side comprises a combination of at least a compression coil spring and a first disk spring arrangement (54) and in that a second rear spring means (60) which faces away from the drilling tool side has a second disk spring arrangement (64).