JP2023073602A - torque limiter - Google Patents

Abstract

To provide a torque limiter capable of preventing the wear of both outer ring member and an inner ring member, regardless of formation material of the inner ring member, without increasing a number of components and costs.SOLUTION: A torque limiter 1 is equipped with an inner ring member 10 around which a coil spring 40 is wound on an outer peripheral surface, and an outer ring member 30 which is arranged so as to cover the inner ring member 10 and to which an end portion 40a of the coil spring 40 is fixed. The outer ring member 30 contains 20-35 pts.wt. of potassium titanate fiber in matrix resin.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiter that limits load torque associated with rotation transmitted in one direction or rotation transmitted in both directions to a predetermined value or less, and more particularly, a torque limiter characterized by an outer ring member (case member). Regarding.

In general, a torque limiter interrupts transmission of torque when a large torque exceeding a certain value acts on a rotation transmission mechanism. It is installed in the roller portion of the transport mechanism (paper feeding mechanism). Such torque limiters include contact type torque limiters that obtain rotational torque by mechanical friction. and an outer ring member (also called a case member or housing) that fixes one end of the coil spring and covers the inner ring member.

In addition to limiting the load torque accompanying the rotation transmitted in one direction, the torque limiter also limits the load torque accompanying the rotation transmitted bidirectionally, as disclosed in Patent Document 2, for example. Limitations are known.

JP 2014-145380 Patent No. 3315603

In recent years, demands for small size, high torque, high durability, and high quality have been increasing for such torque limiters. Therefore, the material for forming the inner ring member around which the coil spring is wound is important in order to improve the quality.

Therefore, the inner ring member is generally molded from sintered metal or resin such as polyphenylene sulfide (PPS), polyetheretherketone (PEEK), and polyeximethylene resin (POM). It is conceivable that durability (abrasion resistance) and sliding properties are improved by incorporating carbon fiber as a filler into the base material such as resin.

However, due to its function, the inner ring member cannot avoid sliding against the outer ring member, and the increased rotational speed used, the radial load, etc. are applied, and the sliding portions of the inner ring member and the outer ring member are still worn. It becomes a problem.

Specifically, for example, as shown in FIG. 5, a known torque limiter 100 incorporated in a separation roller of a paper transport mechanism of a FAX, a printer, or the like includes an inner ring member 102 and an outer circumference of the inner ring member 102. and an outer ring member 106 that fixes one end 104a of the coil spring 104 and covers the inner ring member 102, and a rubber roller 110 as a separation roller is fitted around the outer circumference of the outer ring member 106. It has a structure that In the torque limiter 100 as described above, the first sliding portion A where the inner ring member 102 and the outer ring member 106 contact and slide against each other, the shaft portion 102A that is an extension portion of the inner ring member 102, and the outer ring member 106 are provided. Abrasion occurs in these members 102 (102A) and 106 at the second sliding portion B that contacts and slides against each other.

In particular, if the inner ring member 102 contains carbon fiber in order to improve durability (wear resistance) and sliding properties, as described above, the outer ring member 106 that slides against it is made of a resin such as POM. If formed, the wear of the outer ring member 106 at the first sliding portion A becomes severe. Further, if the outer ring member 106 is made of a wear-resistant reinforced material (containing glass or the like) in order to prevent this, then the inner ring member 102 sliding against the outer ring member 102, especially the shaft portion 102A generally made of a POM material, etc. Wear increases at the second sliding portion B. Furthermore, if the outer ring member 106 is made of a glass-filled wear-resistant reinforcing material, it also affects the inner ring member 102 containing carbon fibers.

In addition, in the structure of FIG. 5, since the rubber roller 110 receives a predetermined pressing force from another opposite rubber roller (not shown), a radial load F acts on the torque limiter 100. If it exceeds (for example, about 100 gf·cm or more), the torque limiter 100 cannot exhibit sufficient performance, and the sliding portions A and B wear more.

In order to prevent such wear at the sliding portions A and B, the shaft portion 102A may be made of metal (for example, SUS) as shown in FIG. As shown in FIG. 2, it is conceivable to interpose a collar 120 as a sliding plate between the sliding portions A and B, but this increases the number of parts and the cost.

The present invention has been made with a focus on the above-described problems, and is capable of reducing the wear of both the outer ring member and the inner ring member, regardless of the material used to form the inner ring member, without increasing the number of parts and increasing the cost. It is an object of the present invention to provide a torque limiter capable of preventing this.

In order to achieve the above object, the present invention provides an inner ring member having a coil spring wound around its outer peripheral surface and an outer ring member arranged to cover the inner ring member and to which the end of the coil spring is fixed. and a torque limiter for generating a predetermined torque between the inner ring member and the outer ring member by the frictional force between the inner ring member and the coil spring while limiting the torque to a predetermined value or less, wherein the outer ring member is characterized by containing 20 to 35% by weight of potassium titanate fibers in a matrix resin.

The inventor of the present invention has made extensive efforts to improve the durability (wear resistance) and sliding characteristics of the inner ring member, regardless of whether the inner ring member is made of a special material or a general resin material. Through various experiments, we explored what kind of material for forming the outer ring member satisfies the condition that it does not wear itself and does not wear itself. It has been found that such conditions are satisfied.

Thus, according to the above configuration of the present invention, since the outer ring member contains 20 to 35% by weight of potassium titanate fiber in the matrix resin, the coefficient of friction and the specific wear amount are low, and the inner ring member is durable. Wear resistance is small even with a special material (for example, a material containing carbon fiber as a filler in a base material such as resin) to improve wear resistance and sliding characteristics, while potassium titanate Since the fibers are softer than carbon fibers, they do not wear the inner ring member. Furthermore, in the structure in which the extension member is provided on the inner ring member as shown in FIG. 5, a common resin is normally used, but abrasion can be prevented even at the sliding portion with these.

Such effects are particularly beneficial when the torque limiter is incorporated in the separation roller of the paper feeding mechanism of electronic information equipment such as facsimiles and printers. That is, since such a separation roller is constantly subjected to a large radial load, the sliding portions (A, B) between the inner ring member (shaft portion) and the outer ring member described above must be particularly durable (abrasion resistant) and sliding. When carbon fiber is contained in the inner ring member to improve the characteristics, or when the shaft portion of the inner ring member is made of POM or the like, abrasion becomes severe. Such wear can be sufficiently prevented by using an outer ring member with a weight percent content. In addition, as described above, there is no need to make the shaft portion metal (for example, SUS) or interpose a collar as a sliding plate in the sliding portions (A, B). growth can be avoided. A method of preventing wear by using a lubricant is also conceivable, but it is desirable to avoid using it in a printer or the like because it may adhere to paper being conveyed.

In the above configuration, if the content of potassium titanate fibers is less than 20%, the outer ring member cannot exhibit sufficient strength, and wear begins to occur. When it exceeds, the formability of the outer ring member deteriorates. The potassium titanate fibers are preferably short fibers having a diameter of 0.3 to 0.6 μm and a length of 10 to 20 μm in consideration of mechanical properties and moldability.

Further, in the above configuration, the inner ring member is preferably made of polyetheretherketone or polyphenylene sulfide as a base material, to which a filler including carbon fiber, polytetrafluoroethylene, and graphite is added. . According to this, it is possible to improve the durability (wear resistance) and sliding characteristics of the inner ring member around which the coil spring is wound.

Here, among the materials to be added, carbon fiber mainly contributes to improvement in strength and wear resistance (improvement in durability), and can also contribute to improvement in sliding properties. In addition, among the added materials, polytetrafluoroethylene and graphite contribute to the improvement of slidability. It has good heat resistance, load resistance, and wear resistance against the increase in pressure of the coil spring, and these complement the functions and stabilize the performance. As the base material, other materials such as polyimide can be used, but polyetheretherketone can exhibit the most excellent properties as the base material. For this reason, if the inner ring member is formed of a composite material having such a base material and the above-described filler, the torque limiter can be made smaller, and even if it is constructed as a high-torque type, the torque is excellent in durability and sliding characteristics. It is possible to configure a limiter.

Even if the inner ring member is made of a special material for improving durability (wear resistance) and sliding properties, the outer ring member is made of the specific material as described above. Therefore, it is possible to prevent abrasion of the sliding portions of the inner ring member (the shaft portion, which is an extension thereof) and the outer ring member.

In the above configuration, the matrix resin of the outer ring member preferably contains at least one of special polyamide, polyphenylene sulfide, polyeximethylene, polyamide 66, polybutylene terephthalate, and polycarbonate. According to this, due to the compound action with the potassium titanate fiber contained in 20 to 35% by weight, the wear of the sliding portions of the inner ring member (the shaft portion that is the extension thereof) and the outer ring member is effectively reduced. can be effectively prevented. Other materials can also be used as the matrix resin for the outer ring member, and depending on the conditions such as the required rotational speed and the radial load to be received, the material ( It is desirable to appropriately select the matrix resin).

According to the torque limiter of the present invention, since the outer ring member contains 20 to 35 wt. Wear of both the outer ring member and the inner ring member can be prevented without causing damage.

1 is a sectional view showing one configuration example of a torque limiter according to the present invention; FIG. FIG. 4 is a cross-sectional view showing another configuration example of a torque limiter according to the present invention; 3 is a schematic side view showing a usage example in which the torque limiter having the configuration of FIG. 2 is incorporated in a separation roller of a paper feeding mechanism of an electronic information device that receives a radial load; FIG. 3A and 3B are enlarged photographs of an outer ring member (housing) and an inner ring member (bobbin) showing a comparison of wear test results of the conventional torque limiter having the configuration of FIG. 2 and the torque limiter of the present invention. and FIG. 10 is a cross-sectional view showing a configuration example of a conventional torque limiter. It is an example of a method for preventing wear at the sliding portions of the inner ring member and the outer ring member. 4A and 4B are diagrams each showing a configuration in which a collar is interposed; FIG.

A torque limiter according to an embodiment of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows one configuration example of a torque limiter according to the present invention. As shown in the figure, this torque limiter 1 includes a cylindrical inner ring member (also called a bobbin) 10 and a cap-shaped outer ring member (case) mounted to cover the inner ring member 10 . (also referred to as a member or housing) 30 and a coil spring 40 mounted on the outer peripheral surface of the inner ring member 10 .

The illustrated coil spring 40 is a one-way coil spring (for example, left-handed), and one end 40 a is fixed to the outer ring member 30 . Therefore, when a predetermined rotational torque is generated from the outer ring member 30 in one direction, the inner ring member 10 and the outer ring member 30 perform a function of causing them to slide (turning off power transmission between the inner ring member 10 and the outer ring member 30). Specifically, when the outer ring member 30 rotates in the direction of arrow D1 in FIG. When the one-way coil spring 40 rotates in the direction of the arrow D2, the one-way coil spring 40 expands (relaxes) in the radial direction. A slip occurs between the mounted one-way coil spring 40 and the power transmission is turned off. That is, such a torque limiter 1 is always in a state of power transmission for rotation in one direction, and for rotation in the opposite direction, slippage between the inner ring portion 10 material and the outer ring member 30 does not occur when a predetermined torque acts. and the power transmission is turned off.

Note that the torque for turning off the power transmission can be adjusted by the tightening force of the one-way coil spring 40 . Further, it is possible to wind a clockwise unidirectional coil spring having a similar structure around the inner ring member 10, and in this case, the effect opposite to that described above can be obtained. Furthermore, it is possible to wind a bidirectional coil spring around the inner ring member 10. In this case, when a predetermined torque is applied to rotation in both directions, slip occurs and power transmission is turned off. becomes. That is, when the load torque in any rotational direction is equal to or less than the torque limit value, the torque is transmitted (ON state), and when the load torque exceeding the torque limit value is applied, the torque transmission is blocked (OFF state). situation).

The inner ring member 10 is formed in a hollow and substantially cylindrical shape, and a shaft (not shown) is inserted through an internal passage 10A. A locking pin (not shown) is provided on the shaft in a direction orthogonal to the axial direction, and a cutout recess 11 that engages with the locking pin is formed radially on one end side of the inner ring member 10 . there is Thereby, the shaft and the inner ring member 10 are rotationally fixed.

The inner ring member 10 has a circumferential wall 10a, and a unidirectional coil spring 40 or a bidirectional coil spring is wound and held on its surface (outer peripheral surface). A peripheral wall 10b having a diameter smaller than that of the peripheral wall 10a is formed on the other end side of the inner ring member 10, and this portion is fitted into a circular opening 31 formed in the top plate wall 30a of the outer ring member 30, thereby forming an outer ring member. The top plate wall 30a side of 30 is positioned.

A flange 12 is integrally formed on the circumferential wall 10a via a plurality of base portions protruding radially at predetermined intervals along the circumferential direction. A coil spring is wound and held on the surface of the circumferential wall 10a. 40 movements are restricted. When the outer ring member 30 is mounted, a pair of protrusions 30c formed at two locations (two locations at 180° intervals) on the inner peripheral surface of the circular opening 30A of the outer ring member 30 and the flange 12 engage with each other. To prevent the inner ring member 10 from slipping out of the member 30. - 特許庁The number of projections to be formed is not limited, and for example, three projections may be formed at intervals of 120°.

In addition, the inner ring member 10 having such a structure is made of polyetheretherketone or polyphenylene sulfide as a base material, to which a filler including carbon fiber, polytetrafluoroethylene, and graphite is added. As a result, the durability (wear resistance) and sliding characteristics of the inner ring member 10 can be improved.

Here, among the materials to be added, carbon fiber mainly contributes to improvement in strength and wear resistance (improvement in durability), and can also contribute to improvement in sliding properties. In addition, among the added materials, polytetrafluoroethylene and graphite contribute to the improvement of slidability. It has good heat resistance, load resistance, and wear resistance against the increase in pressure of the coil spring, and these complement the functions and stabilize the performance. As the base material, other materials such as polyimide can be used, but polyetheretherketone can exhibit the most excellent properties as the base material. For this reason, when the inner ring member 10 is formed of a composite material including such a base material and the above-mentioned filler, the torque limiter can be made smaller, and even if it is constructed as a high-torque type, it has excellent durability and sliding characteristics. It is possible to configure a torque limiter.

As described above, the outer ring member 30 is formed like a cap, and includes a top plate wall 30 a and a circumferential wall 30 b that covers the circumferential wall 10 a of the inner ring member 10 . A circular opening 31 into which the circumferential wall 10b of the inner ring member 10 is fitted is formed in the center region of the top plate wall 30a. The inner peripheral surface of the end portion of the peripheral wall 30b located on the side of the circular opening 31 engages with the locking stepped portion 12a of the flange 12 of the inner ring member 10 as described above to prevent the movement from the outer ring member 30. A pair of protrusions 30c are provided to prevent the inner ring member 10 from coming off.

In the torque limiter 1 configured as described above, the outer peripheral surface of the flange 12 of the inner ring member 10 and the inner peripheral surface of the end portion of the peripheral wall 30b of the outer ring member 30 located on the circular opening 31 side contact each other and slide. While forming the first sliding portion A that moves, the outer peripheral surface of the small-diameter circumferential wall 10b of the inner ring member 10 and the inner peripheral surface of the top plate wall 30a of the outer ring member 30 contact each other and slide. A sliding portion B is formed.

Also, FIG. 2 shows another configuration example of the torque limiter according to the present invention. This configuration is adopted when the torque limiter is incorporated in a separation roller of a sheet feeding mechanism of an electronic information device that receives a radial load F, for example. For this reason, this torque limiter 1A has the same basic configuration as the torque limiter 1 shown in FIG. , and the inner ring member 10 also has a shaft portion 10A integrally extending correspondingly to this length (the inner ring member 10 having the configuration shown in FIG. 1 has a shaft portion 10A as an extending portion). part 10A is integrally formed).

Therefore, in the torque limiter 1A having such a configuration, the outer peripheral surface of the flange 12 of the inner ring member 10 and the inner peripheral surface of the one end portion of the outer ring member 30 form the first sliding portion A that slides in contact with each other. At the same time, the outer peripheral surface of the radially projecting portion 10Aa of the shaft portion 10A of the inner ring member 10 and the inner peripheral surface of the other end portion of the outer ring member 30 form a second sliding portion B that contacts and slides on each other. .

FIG. 3 shows a state in which the torque limiter 1A having the structure shown in FIG. As shown in the figure, the paper feeding mechanism 80 includes a pickup roller 64 that comes in contact with and feeds the uppermost paper sheet P in a stack of paper sheets P, and a rubber roller 60 that is a separation roller (hereinafter referred to as a separation roller). A feed roller (rubber roller) 62 forms a pair with a feed roller (rubber roller) 62 to sandwich the paper P with a predetermined pressure (radial load F acts on the torque limiter 1A) and feed the paper one by one downstream in the transport direction. and In the figure, arrows indicate the direction of rotation of the rollers.

In such a paper feed mechanism 80, when two sheets of paper P are delivered together by the pickup roller 64, a slip occurs between the papers P due to the rotational load of the torque limiter 1A, and the separation roller 60 stops rotating. Prevent double feed.

1 and 2, the outer ring member 30 is formed by containing 20 to 35% by weight of potassium titanate fiber in the matrix resin. In this case, the matrix resin may include special polyamide, polyphenylene sulfide, polyeximethylene, polyamide 66, polybutylene terephthalate, polycarbonate and the like.

As described above, in the present embodiment, the outer ring member 30 is configured by including 20 to 35% by weight of potassium titanate fiber in the matrix resin, so that the friction coefficient and the specific wear amount of the outer ring member 30 are small. Therefore, as described above, the inner ring member 10 is made of a special material (polyether ether ketone or polyphenylene sulfide) for improving durability (wear resistance) and sliding characteristics, and carbon fiber, polytetrafluoro Inner ring member 10 (shaft portion 10A, which is an extension thereof) and outer ring, regardless of whether they are made of either an inner ring member 10 (a composite material formed by adding a filler containing ethylene and graphite) or a general resin material. Abrasion of the sliding portions A and B of the member 30 can be prevented.

This has already been proved by the results of wear tests conducted by the inventors. In this wear test, in the torque limiter configuration of FIG. The outer ring member 30 is made of material X (a material containing 25% by weight of glass beads in polyeximethylene resin) and material Y (a special polyamide as a matrix resin containing 30% by weight of potassium titanate fiber. material). In the wear test, a radial load F of 500 gf was applied to the torque limiter 1A under the same conditions as when the separation roller 60 was assembled into the separation roller 60 in such a state that the separation roller 60 was pressed against the feed roller 62 as shown in FIG. At a rotation speed of 1,000 rpm, the operation rate was 85%, and the on/off operation was repeated until a total of 10,000,000 rotations.

FIG. 4(a) is an enlarged photograph of the outer ring member (housing) 30 and the inner ring member (bobbin) 10 showing the wear test results of a torque limiter (conventional torque limiter) in which the outer ring member 30 is made of material X. FIG. 4(b) is an enlarged photograph of the outer ring member (housing) 30 and the inner ring member (bobbin) 10 showing the wear test results of the torque limiter (torque limiter 1A according to the present invention) in which the outer ring member 30 is made of material Y. is.

As can be seen from these photographs, the conventional torque limiter in which the outer ring member 30 is made of material X contains glass beads. Even if the inner ring member 10 was made of a composite material including polytetrafluoroethylene and a filler containing graphite, abrasion marks were formed on the inner ring member 10 (photograph on the lower side of FIG. 4(a)). reference). On the other hand, in the torque limiter according to the present invention in which the outer ring member 30 is made of material Y, no abrasion was observed on the inner ring member 10 and the outer ring member 30 .

In a torque limiter having an outer ring member 10 made of such a material, even if the inner ring member (bobbin) 10 is made of a relatively high-strength material, the effect of not wearing the sliding portion is exhibited and durability is improved. can be improved. In addition, the outer ring member 10 made of such a material did not cause wear even when the inner ring member (bobbin) was made of POM.

1, 1A torque limiter 10 inner ring member 30 outer ring member 40 coil spring 60 rubber roller (separation roller)
80 paper feeding mechanism

Claims (4)

An inner ring member around which a coil spring is wound and held, and an outer ring member disposed so as to cover the inner ring member and to which an end of the coil spring is fixed, wherein the inner ring member and the coil spring are connected together. A torque limiter that generates a predetermined torque between the inner ring member and the outer ring member by frictional force and limits the torque to a predetermined value or less,
The torque limiter, wherein the outer ring member comprises a matrix resin containing 20 to 35% by weight of potassium titanate fiber. 2. The inner ring member according to claim 1, wherein the inner ring member is made of polyetheretherketone or polyphenylene sulfide as a base material, to which a filler including carbon fiber and polytetrafluoroethylene is added. torque limiter. 3. The torque according to claim 1, wherein the matrix resin of the outer ring member contains at least one of special polyamide, polyphenylene sulfide, polyeximethylene, polyamide 66, polybutylene terephthalate, and polycarbonate. limiter. 4. The rubber roller according to any one of claims 1 to 3, wherein the rubber roller is incorporated in a separation roller of a paper feeding mechanism of an electronic information device that receives a radial load, and a rubber roller forming the separation roller is fitted around the outer circumference of the outer ring member. Torque limiter as described above.

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