阅读说明：本技术 一种气门摇臂总成、可变配气结构及发动机 (Valve rocker arm assembly, variable gas distribution structure and engine ) 是由 董正荣 骆翠芳 陈琳 孟丽 马灵童 于 2021-07-14 设计创作，主要内容包括：本发明涉及发动机领域,公开一种气门摇臂总成、可变配气结构及发动机。一种气门摇臂总成包括：主摇臂,主摇臂转动安装于第一转轴；副摇臂,通过第二转轴转动安装于主摇臂一侧,且第一转轴与第二转轴平行；副摇臂包括第一支臂和第二支臂,且第一支臂与第二支臂连接形成开口背离主摇臂的L形结构；第一支臂背离第二支臂一端用于与凸轮抵接；安装于主摇臂的伸缩装置,伸缩装置与第二支臂传动连接,用于驱动副摇臂绕第二转轴转动。本发明可使发动机在高速区和低速区都能得到满足需求的气门升程,从而改善发动机高速功率和低速扭矩。(The invention relates to the field of engines, and discloses a valve rocker assembly, a variable valve distribution structure and an engine. A valve rocker assembly comprising: the main rocker arm is rotatably arranged on the first rotating shaft; the auxiliary rocker arm is rotatably arranged on one side of the main rocker arm through a second rotating shaft, and the first rotating shaft is parallel to the second rotating shaft; the auxiliary rocker arm comprises a first support arm and a second support arm, and the first support arm and the second support arm are connected to form an L-shaped structure with an opening deviating from the main rocker arm; one end of the first support arm, which is far away from the second support arm, is used for abutting against the cam; and the telescopic device is arranged on the main rocker arm and is in transmission connection with the second support arm and used for driving the auxiliary rocker arm to rotate around the second rotating shaft. The invention can make the engine obtain the valve lift meeting the requirement in both the high-speed area and the low-speed area, thereby improving the high-speed power and the low-speed torque of the engine.)

1. A valve rocker assembly, comprising:

the main rocker arm is rotatably arranged on the first rotating shaft;

the auxiliary rocker arm is rotatably arranged on one side of the main rocker arm through a second rotating shaft, and the first rotating shaft is parallel to the second rotating shaft; the auxiliary rocker arm comprises a first support arm and a second support arm, and the first support arm and the second support arm are connected to form an L-shaped structure with an opening deviating from the main rocker arm; one end of the first support arm, which is far away from the second support arm, is used for abutting against the cam;

and the telescopic device is arranged on the main rocker arm and is in transmission connection with the second support arm and used for driving the auxiliary rocker arm to rotate around the second rotating shaft.

2. A valve rocker assembly as set forth in claim 1 wherein said primary rocker arm has communicating first and second chambers;

the telescoping device includes:

the output piston is matched with the first cavity to form a first piston structure, and one end, deviating from the main rocker arm, of the output piston is in transmission connection with the second support arm;

and the driving mechanism is positioned in the second chamber and is in transmission connection with the output piston and used for adjusting the length of the output piston extending out of the main rocker arm.

3. A valve rocker assembly as set forth in claim 2 wherein said output piston is oriented in a direction perpendicular to said second arm.

4. A valve rocker assembly as claimed in claim 2, wherein a first resilient return member is provided between the output piston and the main rocker arm for always providing the output piston with a force acting towards the drive mechanism.

5. A valve rocker assembly as set forth in claim 2, wherein said drive mechanism comprises:

the input piston is matched with the second chamber to form a second piston structure, and a driving medium for transmitting power is filled between the input piston and the output piston;

and the driving component is in transmission connection with the input piston and is used for driving the input piston to move towards or away from the output piston.

6. A valve rocker assembly as set forth in claim 5, wherein said drive assembly comprises:

the sleeve is connected with the main rocker arm and is positioned in the second chamber;

the magnetic telescopic rod is arranged in the sleeve and is in transmission connection with the input piston, and the magnetic telescopic rod can extend for different lengths under different magnetic field strengths;

and the electromagnetic coil is used for providing a magnetic field for the magnetic telescopic rod.

7. The valve rocker assembly of claim 6, wherein the magnetically stretchable rod is made of a super magnetostrictive material.

8. A variable valve timing structure including the rocker arm assembly of any one of claims 1-7, further comprising:

the cam is in transmission connection with one end, deviating from the second support arm, of the first support arm in the valve rocker arm assembly;

and the valve bridge assembly is arranged on one side, deviating from the cam, of the main rocker arm in the valve rocker arm assembly.

9. The variable valve train of claim 8, wherein the valve bridge assembly comprises:

the valve bridge body is in transmission connection with the main rocker arm and is provided with a third chamber;

the ejection piston is slidably arranged in the third cavity and used for driving the main rocker arm to rotate so as to enable the first supporting arm to be abutted against the cam;

and the second elastic resetting piece is positioned in the third cavity, one end of the second elastic resetting piece is connected with the valve bridge body, and the other end of the second elastic resetting piece is connected with the ejection piston and is used for always providing driving force for the ejection piston.

10. An engine comprising a control module and further comprising a variable valve timing structure according to any one of claims 8 to 9;

and the control module is in signal connection with a telescopic device in the variable air distribution structure.

Technical Field

The invention relates to the technical field of engines, in particular to a valve rocker assembly, a variable valve distribution structure and an engine.

Background

The valve lift of the traditional diesel engine is fixed, namely, only one cam profile of the camshaft is required, so that the lift cannot enable the engine to respond well in a high-speed region and a low-speed region.

Disclosure of Invention

The invention discloses a valve rocker arm assembly, a variable valve distribution structure and an engine, which can enable the engine to obtain a valve lift meeting requirements in a high-speed area and a low-speed area, thereby improving the high-speed power and the low-speed torque of the engine.

In order to achieve the purpose, the invention provides the following technical scheme:

in a first aspect, the present invention provides a valve rocker arm assembly comprising:

the main rocker arm is rotatably arranged on the first rotating shaft;

the auxiliary rocker arm is rotatably arranged on one side of the main rocker arm through a second rotating shaft, and the first rotating shaft is parallel to the second rotating shaft; the auxiliary rocker arm comprises a first support arm and a second support arm, and the first support arm and the second support arm are connected to form an L-shaped structure with an opening deviating from the main rocker arm; one end of the first support arm, which is far away from the second support arm, is used for abutting against the cam;

and the telescopic device is arranged on the main rocker arm and is in transmission connection with the second support arm and used for driving the auxiliary rocker arm to rotate around the second rotating shaft.

Above-mentioned valve rocker assembly includes main rocking arm and vice rocking arm, and telescoping device is installed to main rocking arm, and during the user state, first support arm and cam butt in the vice rocking arm are unchangeable by for camshaft and first pivot position, and telescoping device and vice rocking arm rigid contact, when the telescoping device in the main rocking arm produces the extension displacement, can directly lead to main rocking arm to rotate downwards round first pivot. When the telescoping mechanism in the primary rocker arm is shortened, it directly causes the secondary rocker arm to rotate downward about the second axis of rotation. The maximum stroke of the valve can be changed and the opening phase is not changed under the cooperation of the cam phaser. Specifically, when the engine speed is low, the expansion device generates small extension displacement, so that the valve works under a short stroke, and the output torque at low speed is provided; when the engine speed is higher, the expansion device generates larger extension displacement, and then the valve works under a long stroke, which is beneficial to improving the air intake efficiency at high speed.

Optionally, the primary rocker arm has a first chamber and a second chamber in communication;

the telescoping device includes:

the output piston is matched with the first cavity to form a first piston structure, and one end, deviating from the main rocker arm, of the output piston is in transmission connection with the second support arm;

and the driving mechanism is positioned in the second chamber and is in transmission connection with the output piston and used for adjusting the length of the output piston extending out of the main rocker arm.

Optionally, the direction of motion of the output piston is perpendicular to the second arm.

Optionally, a first elastic resetting piece is further arranged between the output piston and the main rocker arm, and is used for always providing acting force acting towards the driving mechanism for the output piston.

Optionally, the drive mechanism comprises:

the input piston is matched with the second chamber to form a second piston structure, and a driving medium for transmitting power is filled between the input piston and the output piston;

and the driving component is in transmission connection with the input piston and is used for driving the input piston to move towards or away from the output piston.

Optionally, the drive assembly comprises:

the sleeve is connected with the main rocker arm and is positioned in the second chamber;

the magnetic telescopic rod is arranged in the sleeve and is in transmission connection with the input piston, and the magnetic telescopic rod can extend for different lengths under different magnetic field strengths;

and the electromagnetic coil is used for providing a magnetic field for the magnetic telescopic rod.

Optionally, the material for preparing the magnetic telescopic rod is a giant magnetostrictive material.

In a second aspect, the present invention further provides a variable valve timing structure including the valve rocker arm assembly according to any one of the first aspect, further including:

the cam is in transmission connection with one end, deviating from the second support arm, of the first support arm in the valve rocker arm assembly;

and the valve bridge assembly is arranged on one side, deviating from the cam, of the main rocker arm in the valve rocker arm assembly.

Optionally, the valve bridge assembly comprises:

the valve bridge body is in transmission connection with the main rocker arm and is provided with a third chamber;

the ejection piston is slidably arranged in the third cavity and used for driving the main rocker arm to rotate so as to enable the first supporting arm to be abutted against the cam;

and the second elastic resetting piece is positioned in the third cavity, one end of the second elastic resetting piece is connected with the valve bridge body, and the other end of the second elastic resetting piece is connected with the ejection piston and is used for always providing driving force for the ejection piston.

In a third aspect, the present invention further provides an engine, including a control module, further including the variable valve timing structure according to any one of the second aspect;

and the control module is in signal connection with a telescopic device in the variable air distribution structure.

Drawings

FIG. 1 is a schematic illustration of a valve rocker assembly according to an embodiment of the present invention in use;

FIG. 2 is a schematic structural view of the telescopic device;

FIG. 3 is a schematic structural diagram of a driving assembly;

fig. 4 is a schematic structural diagram of a gas distribution assembly according to an embodiment of the present invention;

FIG. 5 is a schematic view of the structure of the valve bridge assembly.

Icon: 100-a main rocker arm; 110-a first shaft; 120-adjusting screws; 200-auxiliary rocker arm; 210-a second shaft; 220-a first support arm; 230-a second arm; 300-a telescoping device; 310-an output piston; 320-an input piston; 330-drive medium; 340-a drive assembly; 341-a sleeve; 342-a magnetic telescopic rod; 343-an electromagnetic coil; 344-plug; 350-a first elastic restoring member; 400-cam; 410-a camshaft; 500-valve bridge assembly; 510-a valve bridge body; 520-ejection piston; 530-a second elastic reset; 540-elephant foot; 550-air valve; 600-a control module.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In a first aspect, as shown in fig. 1 to 3, an embodiment of the present invention provides a valve rocker arm assembly including: a primary rocker arm 100, the primary rocker arm 100 being rotatably mounted on a first rotating shaft 110; the auxiliary rocker arm 200 is rotatably mounted on one side of the main rocker arm 100 through a second rotating shaft 210, and the first rotating shaft 110 is parallel to the second rotating shaft 210; the auxiliary rocker arm 200 comprises a first arm 220 and a second arm 230, and the first arm 220 and the second arm 230 are connected to form an L-shaped structure with an opening departing from the main rocker arm 100; the end of the first arm 220 facing away from the second arm 230 is used for abutting against the cam 400; and the telescopic device 300 is arranged on the main rocker arm 100, and the telescopic device 300 is in transmission connection with the second support arm 230 and is used for driving the auxiliary rocker arm 200 to rotate around the second rotating shaft 210.

The valve rocker arm assembly comprises a main rocker arm 100 and an auxiliary rocker arm 200, wherein the telescopic device 300 is mounted on the main rocker arm 100, when the valve rocker arm assembly is in use, the first support arm 220 in the auxiliary rocker arm 200 is abutted to the cam 400, so that the positions of the cam shaft 410 and the first rotating shaft 110 are unchanged, the telescopic device 300 is in rigid contact with the auxiliary rocker arm 200, and when the telescopic device 300 in the main rocker arm 100 generates extension displacement, the main rocker arm 100 can be directly caused to rotate downwards around the first rotating shaft 110. When the telescopic mechanism in the primary rocker arm 100 is shortened, it directly causes the auxiliary rocker arm 200 to rotate downward about the second rotary shaft 210. The maximum stroke of the valve can be made variable and the opening phase can be made constant by the cooperation of the cam 400 phaser. Specifically, when the engine speed is low, the expansion device 300 generates a small extension displacement, so that the valve works in a short stroke, which is beneficial to providing an output torque at a low speed; when the engine speed is high, the expansion device 300 generates large extension displacement, and then the valve works under a long stroke, which is beneficial to improving the air intake efficiency at high speed.

It can be understood that the main function of the telescopic device 300 is to drive the auxiliary rocker arm 200 to rotate around the second rotating shaft 210 by extending different displacements, or to drive the main rocker arm 100 to rotate around the first rotating shaft 110, so that any structure capable of achieving the above function can be used as the telescopic device 300 in this embodiment, such as an air cylinder, a hydraulic cylinder, or an electric push rod.

Optionally, the primary rocker arm 100 has first and second chambers in communication; the telescopic device 300 includes: the output piston 310 is matched with the first chamber to form a first piston structure, and one end, away from the main rocker arm 100, of the output piston 310 is in transmission connection with the second support arm 230; and a driving mechanism positioned in the second chamber and in transmission connection with the output piston 310 for adjusting the length of the output piston 310 extending out of the primary rocker arm 100.

In a possible implementation manner, the main rocker arm 100 has a first chamber and a second chamber which are communicated with each other, the second chamber is located on a side of the first chamber, which is away from the second support arm 230, the output piston 310 and the first chamber cooperate to form a first piston structure, and the driving mechanism is located in the second chamber and is in transmission connection with the first piston, so as to adjust a length of the first piston, which protrudes out of the main rocker arm 100, that is, to control an extension displacement of the output piston 310.

Optionally, the direction of motion of the output piston 310 is perpendicular to the second arm 230.

It should be noted that the output piston 310 of the primary rocker arm 100 is in a perpendicular relationship with the auxiliary rocker arm 200, which effectively avoids lateral forces on the output piston 310.

In one possible implementation, referring to fig. 1, the end of the output piston 310 facing away from the driving mechanism is hemispherical, and the second arm 230 has a hemispherical recess for engaging with the output piston 310, i.e. the output piston 310 and the second arm 230 are spherically engaged.

Optionally, a first resilient return 350 is also provided between the output piston 310 and the primary rocker arm 100 for always providing a force to the output piston 310 acting towards the drive mechanism.

In a possible implementation manner, the first elastic resetting piece 350 is located in the first chamber, and one end of the first elastic resetting piece 350 is connected with the output piston 310, and the other end is connected with the bottom wall of the first chamber facing to the second chamber, so that the output piston 310 always has a movement tendency to move towards the second chamber. The first elastic restoring member 350 may be embodied as a spring. The output piston 310 is provided with a guide post towards one end of the second chamber, and the spring is sleeved outside the guide post.

Optionally, the drive mechanism comprises: an input piston 320 which forms a second piston structure in cooperation with the second chamber, and a driving medium 330 for transmitting power is filled between the input piston 320 and the output piston 310; a drive assembly 340 drivingly connected to the input piston 320 for driving the input piston 320 toward and away from the output piston 310.

In one possible implementation, referring to fig. 1, the input piston 320 has a larger diameter than the output piston 310, i.e., the first chamber communicates with the second chamber via a third chamber, wherein the cross-sectional area of the third chamber is the smallest and the cross-sectional area of the second chamber is the largest. The third chamber is in sliding fit with the guide post of the output piston 310 to achieve a guiding effect. The input piston 320 is located in the second chamber, the input piston 320 and the second chamber cooperate to form a second piston structure, and the driving assembly 340 provides a driving force for the input piston 320. The drive medium 330 is filled between the input piston 320 and the output piston 310. The input piston 320 acts directly on the output piston 310 through the driving medium 330 to provide a driving force to the output piston 310. The driving medium 330 may be an incompressible fluid, and may specifically be a stream of particles. Particle flow (grain flow), also known as sand flow, refers to the flow of particles caused by the supporting stress generated by the collision between particles without cohesive forces in a flowing deposit, which can transfer shear stress between particles.

Optionally, the drive assembly 340 comprises: a sleeve 341 connected to the main rocker arm 100, the sleeve 341 being located in the second chamber; the magnetic telescopic rod 342 is arranged in the sleeve 341, and the magnetic telescopic rod 342 is in transmission connection with the input piston 320 and can extend for different lengths under different magnetic field strengths; an electromagnetic coil 343 for providing a magnetic field to the magnetic telescopic rod 342.

In one possible implementation, the outer ring of the sleeve 341 is in threaded connection with the main rocker arm 100, the magnetic telescopic rod 342 extends into the sleeve 341, and the side of the sleeve 341 facing away from the input piston 320 is sealed by the plug 344, so that when the magnetic telescopic rod 342 extends, it only acts on the input piston 320 and drives the input piston 320 to move toward the first chamber. The coil is sleeved outside the sleeve 341, an annular recess for winding the coil is formed on the outer side wall of the sleeve 341, and the coil and the sleeve 341 form an electromagnetic coil 343. Electromagnetic coil 343 and engine control module 600(ECU) signal connection, engine control module 600(ECU) provides the electric current of equidimension not (electric current and rotational speed are positive correlation) according to different rotational speeds to electromagnetic coil 343, according to the electromagnetic induction principle, produces the magnetic field (magnetic field intensity is different) along with the rotational speed change in electromagnetic coil 343 axis direction, and the magnetic field intensity along with the rotational speed change makes magnetic telescopic rod 342 produce different extension displacements. Because the input piston 320 and the telescopic magnetic rod 342 are closely attached, the extension displacement of the telescopic magnetic rod 342 directly acts on the input piston 320, and the input piston 320 is connected with the output piston 310 through the driving medium 330, and according to the principle of volume invariance, the displacement ratio of the output piston 310 to the input piston 320 is equal to the area ratio of the input piston 320 to the output piston 310.

Optionally, the material for preparing the magnetic telescopic rod 342 is a super-magnetostrictive material.

It should be noted that, at normal temperature, due to the change of the magnetization state, the length and the volume of the Material change greatly, that is, the Magnetostrictive Material with a very large magnetostriction coefficient is called Giant Magnetostrictive Material (GMM), which is mostly constructed by rare earth, and is also called rare earth Magnetostrictive Material. The material has high heat-resisting temperature and strong magnetostriction performance. At room temperature, the conversion rate between mechanical energy and electric energy is high, the energy density is high, the response speed is high, the reliability is good, and the driving mode is simple. When the external magnetic field exists, the magnetostrictive rod can extend along the direction of the magnetic field and is positively correlated with the magnetic field intensity, and when the external magnetic field disappears, the magnetostrictive rod can recover to the original length.

When the valve rocker arm assembly is applied to an engine, when the engine speed is low, the engine control module 600(ECU) provides a small current for the electromagnetic coil 343, so that the magnetic telescopic rod 342 generates a small extension displacement, and the valve works under a short stroke, thereby being beneficial to providing an output torque at a low speed; when the engine speed is high, the engine control module 600(ECU) provides a large current to the electromagnetic coil 343, so that the magnetic telescopic rod 342 generates a large extension displacement, and the valve operates in a long stroke, which is beneficial to improving the air intake efficiency at high speed.

The following illustrates the application of the valve rocker assembly in the adjustable range of the valve lift in the engine:

the magnetostrictive coefficient lambda of the magnetostrictive rod is 5000ppm, the length L of the magnetostrictive rod is 30mm, and the maximum extension displacement delta L of the magnetostrictive rod is as follows: Δ L ═ λ ═ L ═ 30 ═ 5000 ═ 10e-6 ═ 0.15 mm;

the diameter ratio β of the input piston 320 to the output piston 310 satisfies: β ═ D ═ 4, where D is the diameter of the output piston 310 and D is the diameter of the input piston 320;

the displacement amplification factor γ ═ β ═ 16 of the output piston 310;

maximum displacement L of output piston 310_max＝ΔL*γ＝0.15*16＝2.4mm；

Distance H between valve mounting hole of main rocker arm 100 and second rotating shaft 210₁(i.e. the arm of force of the valve with the second rotating shaft 210 as the fulcrum) and the distance H from the end of the first chamber departing from the second chamber to the second rotating shaft 210₂(i.e. the arm of force of the output piston 310 with the second rotating shaft 210 as the fulcrum) satisfies the condition that alpha is H₁/H₂＝2；

100 valve side maximum of main rocker armSwing height h_max＝L_max*α＝2.4*2＝4.8mm；

I.e. valve lift l ∈ [ ]_min，l_min+4.8mm]。

It should be noted that, the above-mentioned valve rocker arm assembly has a two-stage amplification structure, which respectively is:

firstly, amplification between the input piston 320 and the output piston 310, wherein the displacement ratio of the output piston 310 to the input piston 320 is equal to the area ratio of the input piston 320 to the output piston 310;

and secondly, the moment arm of the valve and the moment arm of the output piston 310 are amplified by taking the second rotating shaft 210 as a fulcrum.

In a second aspect, based on the same inventive concept, as shown in fig. 4 and 5, an embodiment of the present invention further provides a variable valve timing structure, including any one of the rocker arm assemblies in the first aspect, further including: the cam 400 is in transmission connection with one end, away from the second support arm 230, of the first support arm 220 in the valve rocker arm assembly; and the valve bridge assembly 500 is arranged on one side, away from the cam 400, of the main rocker arm 100 in the valve rocker arm assembly.

Optionally, the valve bridge assembly 500 comprises: a valve bridge body 510 in driving connection with the main rocker arm 100, the valve bridge body 510 having a third chamber; an ejector piston 520 slidably mounted in the third chamber for driving the main rocker arm 100 to rotate so that the first arm 220 abuts against the cam 400; and the second elastic resetting piece 530 is positioned in the third chamber, one end of the second elastic resetting piece 530 is connected with the valve bridge body 510, and the other end of the second elastic resetting piece 530 is connected with the ejection piston 520, so that driving force is always provided for the ejection piston 520.

In one possible implementation, referring to FIG. 4, a valve bridge assembly 500 is mounted to the valve side of the main rocker arm 100 by an elephant foot 540 and an adjustment screw 120.

It should be noted that the ejection piston 520 in the valve bridge assembly 500 not only allows the lost motion of the cam 400, but also allows the roller in the auxiliary rocker arm 200 to be in contact with the camshaft 410 at all times. When ejection piston 520 is ejected to a certain height, a portion of the stroke of cam 400 may be offset, i.e., an idle stroke of cam 400 is achieved. Since the camshaft 410 and the rocker shaft are stationary and the output piston 310 is in rigid contact with the auxiliary rocker arm 200, the primary rocker arm 100 is directly caused to pivot downward about the rocker shaft when the telescoping mechanism in the primary rocker arm 100 is extended. When the telescopic mechanism in the main rocker arm 100 is shortened, the auxiliary rocker arm 200 is directly caused to rotate downwards around the rotating shaft of the auxiliary rocker arm 200, and at the same time, the ejection piston 520 in the valve bridge assembly 500 is ejected upwards under the action of the second elastic resetting piece 530 (such as a compression spring), so that the auxiliary rocker arm 200 rotates upwards around the rotating shaft of the auxiliary rocker arm 200, and the roller in the auxiliary rocker arm 200 is always in contact with the camshaft 410. The maximum stroke of the valve 550 may be made variable and the opening phase may be made constant with the cooperation of the cam 400 phaser.

In a third aspect, based on the same inventive concept, embodiments of the present invention further provide an engine, including a control module 600, and further including any one of the variable valve timing structures in the second aspect; the control module 600 is in signal connection with the expansion device 300 in the variable air distribution structure.

Referring to fig. 1 and 4, the engine control module 600(ECU) provides the electromagnetic coil 343 with a current varying with the rotation speed, so that the telescopic magnetic rod 342 generates different telescopic displacements. When the engine speed is low, the engine control module 600(ECU) provides a small current to the electromagnetic coil 343, so that the magnetic telescopic rod 342 generates a small extension displacement, and the valve operates in a short stroke, thereby being beneficial to providing an output torque at a low speed; when the engine speed is high, the engine control module 600(ECU) provides a large current to the electromagnetic coil 343, so that the magnetic telescopic rod 342 generates a large extension displacement, and the valve operates in a long stroke, which is beneficial to improving the air intake efficiency at high speed.

It will be apparent to those skilled in the art that various changes and modifications may be made in the embodiments of the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.