Composite Cam Follower Tappet with Dry Lubricant
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Solution Overview
Problem
Polymer materials used in cam followers for motor vehicle injection pumps and valve actuators suffer from dimensional instability and moisture absorption under high temperatures and humidity, leading to potential failure and engine issues due to inadequate lubrication and wear.
Innovation Solution
A cam follower made of a composite material with reinforcement fibers and integrated dry lubricants, such as graphite or PTFE, which reduces wear and provides lubrication, improving the cam follower's lifespan and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymer material is used for the tappet, then the cam follower can be manufactured with ease and reduced weight, but dimensional stability deteriorates under high temperature and humidity conditions
Solution Approach 1:
The tappet is made from a composite material consisting of a polymer matrix (such as polyamide or polyphtalamide) reinforced with fibers (glass, carbon, or para-aramid) and incorporating dry lubricant particles. This composite structure maintains the ease of manufacturing and weight advantages of polymers while significantly improving dimensional stability under high temperature and humidity conditions through the reinforcing fibers.
2Ease of manufacture
If polymer material is used for the tappet, then manufacturing cost is reduced, but wear resistance deteriorates under harsh operating conditions
Solution Approach 1:
The composite material combines polymer matrix with reinforcing fibers and dry lubricant particles, maintaining cost-effectiveness while dramatically improving wear resistance. The fibers provide structural strength and wear resistance, while the dry lubricant particles (graphite, PTFE, or MoS2) reduce friction and wear during operation.
Solution Approach 2:
The dry lubricant particles are integrated within the polymer matrix of the tappet itself, allowing the tappet to self-lubricate during operation. As the tappet wears or undergoes plastic deformation, the dry lubricant particles are released at the cylindrical outer surface, providing continuous lubrication without requiring external lubrication systems.
3Weight of moving object
If polymer material is used for the tappet, then the cam follower weight is reduced, but lubrication performance deteriorates under high temperature conditions
Solution Approach 1:
The tappet uses a composite material combining lightweight polymer matrix with dry lubricant particles, maintaining weight reduction while improving lubrication performance. The dry lubricant particles compensate for the polymer's insufficient lubrication properties under high temperature and humidity conditions.
Solution Approach 2:
The dry lubricant particles integrated in the polymer matrix provide self-lubrication functionality. During operation, particularly under high temperature and humidity conditions, the dry lubricant particles are released at the cylindrical outer surface through plastic deformation or wear, ensuring satisfactory lubrication performance throughout the cam follower's service life.
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 composite material with dry lubricants enhances the cam follower's durability and lubrication, reducing wear and extending its operational life, even under harsh conditions.
Implementation Method 1
the at least one dry lubricant integrated to the tappet is adapted to be released at the cylindrical outer surface when the cam follower is in operation
Implementation Method 2
the at least one dry lubricant integrated to the tappet is adapted to be released at the cylindrical outer surface when the cam follower is in operation
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention concerns a cam follower (1) comprising a tappet (10) having a cylindrical outer surface (14) centered on a longitudinal axis (Y1) and adapted to slide in a housing (2) surrounding the tappet, a pin extending between two opposite ends along a transverse axis (X1) perpendicular to the longitudinal axis, and a roller element movable in rotation relative to the pin around the transverse axis and adapted to roll on a cam. The tappet (10) is made of a composite material integrating at least one dry lubricant released at the cylindrical outer surface (14) when the cam follower (1) is in operation. The invention also concerns an injection pump and a valve actuator for a motor vehicle, each comprising such a cam follower (1). The invention also concerns a method for manufacturing such a cam follower (1).