Gear Images Free

[Anthony]

For this time, I decided to focus mostly on the GF110mmF2 images, since a fellow GFX group member asked to stop sharing GF110 images, as they trigger his GAS and he is preparing his papers for the divorce ;).

Because medium format is nice and good, but what you can achieve with modern APS-C sensors (and fantastic Fujifilm XF glass), is something that can be shown and printed proudly (such as my personal all time favorite image taken with X-T1)!

Disclaimer: Fujirumors has no affiliation with any of the equipment manufacturers mentioned on this site. Please visit their official websites by typing the specific brand name and adding .com after it in your browser. All trademarks and brands belong to their respective owners.

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Michael Strickland is a fine art landscape photographer based out of his home state of Kansas. Michael creates all of his images on medium and large format film and aims to create peaceful images of the United States from the Kansas landscape to the California Big Sur seascape.

It is necessary to accurately understand the differences among gear types to accomplish necessary force transmission in mechanical designs. Even after choosing the general type, it is important to consider factors such as: dimensions (module, number of teeth, helix angle, face width, etc.), standard of precision grade (ISO, AGMA, DIN), need for teeth grinding and/or heat treating, allowable torque and efficiency, etc.

Besides this page, we present more thorough gear technical information under Gear Knowledge (separate PDF page). In addition to the list below, each section such as worm gear, rack and pinion, bevel gear, etc. has its own additional explanation regarding the respective gear type. If it is difficult to view PDF, please consult these sections.

It is best to start with the general knowledge of the types of gears as shown below. But in addition to these, there are other types such as face gear, herringbone gear (double helical gear), crown gear, hypoid gear, etc.

A gear is a kind of machine element in which teeth are cut around cylindrical or cone shaped surfaces with equal spacing. By meshing a pair of these elements, they are used to transmit rotations and forces from the driving shaft to the driven shaft. Gears can be classified by shape as involute, cycloidal and trochoidal gears. Also, they can be classified by shaft positions as parallel shaft gears, intersecting shaft gears, and non-parallel and non-intersecting shaft gears. The history of gears is old and the use of gears already appears in ancient Greece in B.C. in the writing of Archimedes.

Simply said, a gear meshes with another gear while a sprocket meshes with a chain and is not a gear. Aside from a sprocket, an item that looks somewhat like a gear is a ratchet, but its motiion is limited to one direction.

Existence of teeth grinding greatly affects the performance of gears. Therefore, in considering types of gears, teeth grinding is an important elememt to consider. Grinding the teeth surface makes gears quieter, increases force transmission capacity and affects the precision class. On the other hand, the addition of teeth grinding process increases cost and is not suitable for all gears. To obtain high precision other than by grinding, there is a process called shaving using shaving cutters.

To broadly classify types of gears by their tooth shape, there are involute tooth shape, cycloid tooth shape and trochoid tooth shape. Among these, involute tooth shape is most commonly used. They are easy to produce and has the characteristic of being able to correctly mesh even when the center distance is slightly off. Cycloid tooth shape is mostly used in clocks and trochoid tooth shape is mainly in pumps.

There are many ways to transmit rotation and power from one shaft to another such as by rolling friction, wrapping transmission, etc. However, in spite of a simple structure and a relatively small size, gears have many advantages such as certainty of transmission, accurate angular speed ratio, long lasting and minimal loss of power.

From small clocks and precision measuring instruments (motion transmission applications) to large gears used in marine transmission systems (power transmission applications), gears are used widely and are ranked as one of the important mechanical components along with screws and bearings.

There are many types of gears. However, the simplest and most commonly used gears are the ones used to transmit specific speed ratio between two parallel shafts at a defined distance. In particular, gears with their teeth parallel to the shafts as shown in Figure 1.1 called spur gears are the most popular.

The simplest method to transmit specific angular speed ratio between two parallel shafts is a rolling friction drive. This is accomplished as shown in Figure 1.2, by having two cylinders, with diameters in inverse ratio to the speed ratio, in contact and rotating without slippage (if two shafts are counter rotating, contact is on the outside; and if rotating in the same direction, contact is on the inside). That is to say that the rotation is obtained from the friction force of the rolling contact. However, it is impossible to avoid some slippage and, as a result, reliable transmission cannot be hoped for. To get a larger power transmission requires heavier contact forces which in turn result in high bearing loads. For these reasons, this arrangement is not suitable for transmitting large amount of power. As a result, an idea to create suitable form of teeth equally spaced on the rolling surfaces of the cylinders in such a way that at least one pair or more of teeth are always in contact was invented. By pushing the teeth of the trailing shaft with the teeth of the driving shaft, the certainty of a strong transmission is assured. This is called a cylindrical gear and the reference cylinder on which the teeth are carved is the pitch cylinder. Spur gears are one type of cylindrical gears.

When two shafts intersect, the references for carving teeth are the cones in rolling contact. These are the bevel gears as shown in Figure 1.3 where the base cone on which teeth are carved is called the pitch cone. (Figure 1.4).

When the two shafts are not parallel and non-intersecting, there are no true rolling contacting curved surfaces. Based on the type of gears, teeth are created on a pair of reference contacting rotating surfaces. In all cases, it is necessary to set the tooth profile such that the relative motion of the contacting pitch surfaces matches the relative motion of the meshing of the teeth on the reference curved surfaces.

When gears are considered as rigid bodies, in order for two bodies to maintain a set angular speed ratio while in contact at teeth surfaces, without running into each other or separating, it is necessary for the common normal components of speed of the of the two gears at the contact point to be equal. In other words, at that instant, there is no relative motion of the gear surfaces in the direction of the common normal, and the relative motion exists only along the contact surface at the point of contact. This relative motion is nothing but the sliding of gear surfaces. The tooth surfaces, with the exception of special points, always involve the so-called sliding contact transmission.

It is also possible to lead to tooth forms by the following method. Consider, in addition to a pair of gears A and B with specified relative motion, a third imaginary gear C in mesh where A and B are in mesh and give it an arbitrary tooth form surface FC (curved surface only without tooth body) and an appropriate relative motion.

Now, using the method as before, from the imagined meshing of gear A with the imaginary gear C, obtain the tooth form FA as the envelope of tooth form FC. Designate the contact line of tooth surfaces FA and FC as IAC. Similarly, obtain the contact line IBC and tooth surface FB from the imaginary meshing of gear B and the imaginary gear C. Thus, the tooth surfaces FA and FB are obtained by the mediation of FC. In this case, if the contact lines IAC and IBC match, gears A and B are in line contact, and if IAC and IBC intersect, gears A and B will have a point contact at that intersection.

However, there are limits to geometrically obtained tooth forms as explained above, especially when the tooth bodies of surfaces FA and FB invade each other, or when those areas cannot be used as tooth forms. This invasion of one tooth body into another is called interference of tooth profiles.

As clear from the above explanation, there are theoretically many ways to produce tooth forms which create specified relative motion. However, in reality, consideration for the gear mesh, tooth form strength and difficulties of tooth cutting will limit the usage of these kinds of tooth forms to just a few.

Gears have been used worldwide since ancient times in many applications and are representative components of machine elements. However, as far as the precision class of gears, there are industrial standards in various countries such as AGMA(US), JIS(Japan), DIN(Germany), etc. On the other hand, there are no standards with regard to factors which ultimately specifies [the gear itself] such as its form, size, bore diameter, material, hardness, etc. As a result, there is no unified approach but it is a collection of the actual gear specifications decided by the individual designers that suits the design of their machines or those decided by the individual gear manufacturers.

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