Basic knowledge of non-standard tool drill chuck

Drill chuck is one of the main accessories in the power tool industry and machine tool industry, and is widely used in hand electric drills and drilling machines. grid model.

The chuck is an accessory that is connected to the drilling tool and used to hold shank tools. There are two ways to connect it with the drilling tool: threaded connection and taper hole connection. According to the current chuck specifications, the main specifications of threaded connections are 3/8-24UNF, 1/2-20UNF, 5/8-16UN, and M12×1.25. Must have B10, B12, B16, B18, B22 and JT0, JT2, JT3, JT6, JT10, JT33 and other specifications. The threaded connection is mainly used on hand electric drills, and the taper connection is mainly used on drilling machines.

The three main parameters of a collet are accuracy, clamping force and clamping range. Accuracy is used to control the runout of tools such as clamping shanks to ensure the accuracy of machining holes. The clamping force is to ensure that the gripped shank tools do not slip, and prevent the shank tools from being unable to work due to the slippage of the shank tools. In general, the accuracy of the chuck used on the bench drill is higher, while the accuracy of the chuck used on the hand drill is relatively low. The clamping range is used to control the minimum and maximum diameters of the collet clamping tool to meet the needs of the work. Under normal circumstances, the maximum clamping range is only about 0.5mm larger than the size of the chuck. If it is too large, it will greatly waste materials and increase the production cost of the chuck. Theoretically, the minimum clamping range can be made very small, but if it is too small, the reject rate of the manufacturer will increase and the cost will be increased. Therefore, considering all aspects of the situation, the clamping range of 6, 10, 13, 16, 20mm chucks is set as 0.8-6, 0.8-10, 1.5-13, 3-16, 5-20 comparison Reasonable.

Size refers to the maximum diameter that the collet will hold. The specifications of drill chucks are divided into 6, 10, 13, 16, 20mm and other specifications. There are generally only three types of hand-tight drill chucks, 6, 10, and 13 mm, because if they are larger, the clamping force of the chuck cannot meet the requirements of use. Because the wrench chuck is tightened by a wrench wheel, the clamping force of the chuck is large, so the size can be 20mm. The model of the chuck generally starts with "J", "J" means the chuck, followed by 3-4 numbers, such as J1510, J1713, etc. The specific meaning of the numbers will be explained below.

Drill chucks are mainly divided into two categories: wrench type and hand-tight type. Wrench-type drill chucks need to be tightened with a pull wheel, and are mainly used in the machine tool industry, such as bench drills and hand drills. The hand-tight drill chuck is mainly used for hand electric drills by holding the front and rear sleeves to tighten the chuck. Because the wrench drill chuck is tightened by the pull wheel, and the pull wheel is a bevel gear with an extended arm, it can increase the torque input during the tightening process. Therefore, the clamping of the chuck Powerful. Due to the advantages of simple structure, easy processing of parts, low price and reliable performance, the wrench collet has a wide range of uses. The main categories of wrench chucks are introduced below.

Wrench chucks can be divided into light, medium and heavy according to their use. The difference between light and heavy mainly depends on the structure of the silk ferrule. The light-duty collet wire nut is stamped and formed, and the heavy-duty is cold-extruded, with high strength. The model format of the light chuck is J35_ _, J25_ _, and the last two digits are used to fill in the clamping range of the chuck, such as 10, 13, etc. 35 indicates that the connection between the chuck and the drilling tool is a threaded connection; 25 indicates a taper hole connection. Lightweight wrench drill chucks are mainly used for household drilling tools, suitable for DC and AC electric drills of different powers. In recent years, in order to reduce the production cost, powder metallurgy materials have been used for the nut, which greatly improves the production efficiency and reduces the tooth profile error of the bevel teeth.

Medium and heavy-duty chucks are mainly used for woodworking machine tools, bench drills, machining centers and other equipment with a large load. The bevel gears used for torque input are all steel teeth, which can bear large torque.

According to its structure, hand-tight drill chucks are divided into lock, without lock, single set and double set. Specifically, the models are divided into J15_ _, J17_ _, J16_ _, J18_ _. Among them, 15 means double sets without lock chuck, 17 means double sets with lock chuck, 16 means single set without lock chuck, 18 means single set with lock chuck. The two digits behind _ _ indicate the size of the collet. For example, J1510 means double sets of 10mm chucks without locks. If it is a 6mm chuck, it can be directly expressed as J156.

Hand-tight drill chucks are mainly used for domestic DC and AC drills. Its biggest advantage is that it is easy to lock, as long as you hold the front and rear sleeves of the collet and tighten it to use. Depending on the internal structure of the drill chuck, the suitable electric drill is also different.

Drill chucks of the J15 series for DC and AC drills without impact. According to the customer's request, the jacket of the collet has two kinds of metal sleeve and nylon sleeve. The metal sleeve can increase the service life of the collet, but because the metal sleeve is heavier than the nylon sleeve, its moment of inertia is larger. During the use of the chuck, due to the change of the rotational speed of the electric drill, it is easy to loosen itself, so when designing the chuck, try to reduce the size of the driven part of the chuck and reduce its moment of inertia.

J17 series drill chucks can be used for DC and AC drills with and without impact. Because of its internal anti-loosening mechanism, it has good performance, so it is more and more favored by users.

From the point of the lock, there are mainly several structures such as ratchet lock, friction lock, wedge lock and force-enhancing lock. The ratchet lock has the characteristics of simple structure and reliable locking. This type of chuck will make a "click, click" sound when it is locked to indicate that the chuck is in a locked state. According to the structure of the lock, the chuck of the ratchet lock is suitable for the impact drill between 700-1000W. Especially when drilling concrete, it will show good performance.

The friction lock mainly relies on friction to lock the chuck, and its reliability is lower than that of the ratchet lock. It is mainly used for AC drills below 750W and DC drills below 18V. This collet is mainly designed to meet the occasions where customers sometimes do not need the "click, click" locking sound.

The wedge lock is actually a kind of friction lock, which is locked by using the inclined surface to squeeze the roller (ball).

In order to increase the torque input, on the basis of J15 and J17, J16 and J18 series single-set chucks have been developed. Mainly to increase the grip area and increase the tightening torque. Due to its larger torque input, the single-set series collet has more reliable performance than the double-set collet. In addition, the single-set product is especially suitable for electric drills with shaft locks, because a large torque can be input.

When the chuck is delivered to the customer, the customer generally needs to test the two main properties of the chuck, one is the accuracy, and the other is the clamping force. The accuracy test method is shown in the figure on the right. In general

, the accuracy of the chuck is checked by the inspection rod with the largest clamping range. Such as 10mm chuck, use ∮10mm test rod to measure its accuracy. Since the internal thread of the collet is a tapered thread, the rise angle of each thread on the jaw and nut varies. Therefore, in the different clamping range of the collet, the accuracy of the collet is different. Now with the improvement of processing quality, this difference is getting smaller and smaller.

The chuck clamps torque rods with different diameters. Due to the different friction arm and the curvature radius of the torque rod, the output torque is also different, that is, the clamping force is also different. The size of the clamping force will directly affect the performance of the chuck. Therefore, this item is strictly controlled by the manufacturer when the product leaves the factory.

Different customers and different applications of the chuck have different requirements for accuracy and clamping force. In general, the higher the accuracy and clamping force, the higher the price of the collet. Therefore, under normal circumstances, customers are generally subject to the national standard. In addition, the collet fails during use, and sometimes it is not necessarily a problem of the collet, it may be a problem of use, or it may be a problem of concrete.

In recent years, with the improvement of the production collet process water, the precision and clamping force of the collet are constantly improving. Now we have basically reached the level of foreign countries. But we still have a lot of room for improvement. As a leader in the chuck industry, Ouli has been ahead of its domestic counterparts in this regard, and its products have gradually replaced foreign products at home and abroad.

In short, although the collet is a small power tool accessory, it involves many types, and users need to choose the appropriate collet according to their respective usage conditions. Hope the above knowledge will be helpful to you.