JP5542873B2 - Gear and gear design method - Google Patents

Description

  The present invention relates to a gear widely used in a gear pump, a compressor, and the like and a rotating mechanism of these parts.

  For example, measures against the confinement that becomes a problem when oil is transferred by a gear pump are generally devised by machine elements other than gears.

  On the other hand, in a compressor in which the fluid is a gas, a gear having three teeth and having an involute curve is being used as a countermeasure against pulsation of discharged air caused by a change in volume of the confined portion.

  However, since the tooth profile is an involute curve, the sealing performance of the confined portion is not sufficient, and there is a possibility that a non-negligible amount of the inhaled gas flows backward.

  More specifically, when a pair of gears each having teeth formed only by an involute curve are meshed and used as a gear pump or a compressor, as shown in FIG. In the engagement of the gear 100d, when contact occurs at two points such as the contact points A and B, a confinement T in which fluid is confined between the tooth tip and the tooth bottom occurs.

  Furthermore, as shown in each drawing of FIG. 11, the volume of the confinement T changes greatly with the rotation of the gear, so that the fluid in the confinement T is greatly compressed or expanded, thereby causing pulsation. And since the gap | interval of a meshing part is large, sealing performance is also bad, and in the case of gas especially, the problem of a backflow or a leak becomes remarkable.

  In order to solve such a problem related to confinement, in Patent Document 1, a predetermined section before and after the pitch circle is formed by an involute curve, and a gear having a tooth tip portion and a tooth root portion formed in a symmetrical partial arc shape is used. It has been shown to be used.

  However, Patent Document 1 does not clearly show from which part of the tooth the involute curve part between the tooth tip part and the tooth root part starts and ends. Therefore, when a pair of gears are engaged with each other, for example, there may be a state in which the partial arc of the tooth tip portion and the involute curve are in contact with each other. May adversely affect the transport of Therefore, even if the gear described in Patent Document 1 is formed, it does not always become a gear that can be actually used because discontinuous meshing occurs.

  However, in order to reduce the pulsation due to the confinement and make the meshing transmission excellent, all the tooth forms as described above are formed with an involute curve. If the gear size is large and the gear size is small, the tooth base becomes thin, causing a problem in strength.

Registered Utility Model Publication No. 3068699

  Therefore, the present invention has been made in view of the above-described problems, and can eliminate the closed portion or can reduce the volume change of the closed portion due to the rotation of the gear, and the sealing performance at the meshing portion. An object of the present invention is to provide a gear and a gear design method for the gear that can be engaged only on an involute curve from the start to the end of the engagement.

  That is, each invention of the present application is excellent in meshing transmission even if it is a tooth profile composed of an arc and an involute curve as described in Patent Document 1, and the inventor of the present application defines conditions that can be actually used. It was also discovered after intensive studies.

  More specifically, the gear of the invention according to claim 1 of the present invention is a tooth tip portion whose tooth profile is formed symmetrically with respect to the tooth tip reference line by a quadratic curve convex outwardly; A tooth base portion formed symmetrically with respect to the tooth root reference line by a quadratic curve that protrudes inward, and a rotation mesh formed by an involute curve occurs between the tooth tip portion and the tooth root portion. A pair of gears, each having a tooth shape formed by repeating the tooth tip portion, the rotation meshing portion, the tooth root portion, and the rotation meshing portion in this order. And the rotation of each gear in a state where the center line connecting the rotation axes of the gears and the tooth base reference line of one gear coincide with each other when viewed from the axial direction. Involute curve and each tooth forming the meshing part The intersection of the base circle and the common tangent of the other gear is a connection point of the tooth tip part and the rotation meshing part of the other gear, and the rotation meshing part and the tooth root part of one gear. It is set to a tooth root part connection point that is a connection point, and the quadratic curve forming the tooth tip part is a line with respect to the tooth tip part connection point and the tooth tip part connection point and the tooth tip reference line. It is connected so that it has a common tangent with an involute curve that forms each rotation meshing portion at each point through a point at a symmetric position, and a quadratic curve that forms the tooth root portion is connected to the tooth root portion. It is connected so that it has a common tangent with an involute curve that forms each rotation meshing part at each point through a point and a point that is line-symmetric with respect to the tooth root reference line and the tooth root reference line. The tooth tip part and the tooth base part have substantially the same shape. Characterized in that is formed by the following curve.

  Here, the basic circle is used to draw an involute curve at the meshing portion. The quadratic curve is a concept including, for example, a perfect circle, an ellipse, and a parabola. In addition, the quadratic curve is sometimes referred to as a conic curve, and indicates a curve appearing in a cross section of the cone.

  If it is such, the point where the quadratic curve which forms the tooth tip part is in a line symmetrical position with respect to the tooth tip connecting point and the tooth tip connecting point and the tooth tip reference line. The involute curve that forms each rotation meshing portion at each point is connected so as to have a common tangent line, and the quadratic curve that forms the root portion is connected to the root portion connection point and the root portion connection. A point and a point that is line-symmetric with respect to the tooth base reference line, and each point is connected so as to have a common tangent with an involute curve that forms each rotational meshing portion, Since the tooth root part is formed by a quadratic curve having substantially the same shape, the tooth tip part and the tooth root part can be substantially matched at the time of rotation meshing, so that the confinement can be eliminated. Further, even if the tooth tip portion and the tooth root portion are slightly separated from each other, since the tooth tip portion and the tooth root portion are formed by the same shape of the quadratic curve, at the time of rotational meshing, The period during which the gear and the other gear are in contact with each other at two points can be shortened, so that the confinement hardly occurs and the volume can be minimized even if it occurs.

  Also, in a state where the pair of gears are in mesh with each other, and when viewed from the axial direction, the center line connecting the rotation axes of the gears coincides with the tooth root reference line of one gear. , The intersection of the involute curve forming the rotating meshing portion of each gear and the common tangent of the basic circle of each gear is the connecting point of the tooth tip portion and the rotating meshing portion of the other gear And, since the tooth engagement point is the connection point between the rotating meshing part and the tooth root part of one gear, the meshing start point is set to the tooth tip connection point, and the meshing end A point can be set as the tooth root connection point.

  Accordingly, the rotation meshing portion between the tooth tip connection point and the tooth root connection point is set in a necessary and sufficient region from the start to the end of the meshing. The transmission can be improved.

  Furthermore, since the tooth tip portion and the tooth root portion are formed by a quadratic curve, not an involute curve, the shapes of the tooth tip portion and the tooth root portion are substantially matched to eliminate the closure, or The confinement can be reduced, and the change in volume accompanying the rotation of the gear can be reduced. In addition, since the tooth tip part is formed by a quadratic curve, the tooth surface of the tooth tip is present on the inner side as compared with the case where it is formed by an involute curve, which does not contribute to meshing and is wasteful. No significant interference occurs.

  In addition, since the root portion is formed by a quadratic curve, even when the number of teeth is reduced in order to increase the space volume between the teeth in a small gear, compared to the case where the tooth portion is formed by an involute curve. The tooth base can be thickened and the strength can be maintained.

  In other words, if the tooth profile of the present invention is used when a space volume between teeth is required, the size of the gear can be reduced by increasing the module and selecting a smaller number of teeth.

  3. To reduce the volume of the confinement due to the rotation of the gear and reduce the change in the confinement volume even when there is backlash, to achieve a gear having high meshing transmission and sealing performance. In the case where a backlash exists between a pair of gears as in the invention, the contact point when the other gear is rotated and brought into contact with one gear is set as the tooth tip connection point. That's fine.

  As a design method suitable for designing the gear of the present invention, the tooth profile is formed symmetrically with respect to the tooth tip reference line by a quadratic curve protruding outward as in the invention of claim 3. A tooth root portion formed symmetrically with respect to the tooth root reference line by a quadratic curve convex inward, and formed by an involute curve between the tooth tip portion and the tooth root portion A gear of a gear having a tooth shape formed by repeating the tooth tip portion, the rotation meshing portion, the tooth root portion, and the rotation meshing portion in this order. A design method, in which a pair of gears are in mesh with each other, and when viewed from the axial direction, a center line connecting the rotation axes of the gears coincides with the tooth base reference line of one gear. The gear placement step to put in a state, The intersection of the involute curve forming the rotation meshing portion and the common tangent of the basic circle of each gear, the tooth tip connection point that is the connection point of the tooth tip portion and the rotation meshing portion in the other gear, A connection point setting step for setting a tooth root connection point that is a connection point between the rotating meshing portion and the tooth root portion of the gear; the tooth tip connection point, the tooth tip connection point, and the tooth tip reference line; A tooth tip portion forming step of forming the tooth tip portion by a quadratic curve that is connected so as to have a common tangent line and an involute curve that forms a rotational meshing portion at each point through a point that is in line symmetry with respect to the point; And a common tangent line that passes through the tooth base connection point and a point in line symmetry with respect to the tooth base connection point and the tooth base reference line, and forms a rotational meshing portion at each point. Like A tooth root portion forming step of forming the tooth root portion by a secondary curve connecting include gear design method characterized by comprising the.

  Further, in order to allow the gear design to be appropriately performed in consideration of the backlash, the backlash exists between the pair of gears as in the gear design method according to the invention of claim 4. Then, the contact point when the other gear is rotated and brought into contact with one gear may be set as the tooth tip connection point.

  According to the gear and the gear design method of the present invention, the rotation mesh portion formed by the involute curve is formed from the start point to the end point of the rotation mesh, and the other tooth tip portion and the tooth root portion are secondary. By using a tooth profile formed by a curve, it is possible to eliminate the closing when the pair of gears are engaged with each other, or to reduce the amount of change in volume due to the rotation of the gears while making the volume of the closing very small. it can. Furthermore, if the gear of the present invention is not closed or can be made very small even if it exists, the fluid efficiency at the meshing portion is improved, and the volumetric efficiency when configured in a pump, etc. Can be improved.

  Since high sealing properties can be provided in this way, air can be selected as the fluid to be pushed out and used as a compressor or a flow meter.

  Further, since the tooth root portion is formed by a quadratic curve, the tooth root can be made thicker even when the number of teeth is reduced and the module is made larger than when it is formed by an involute curve. Therefore, even if the gear is small and has a small number of teeth, the strength of the tooth root can be improved, and the space volume between the teeth can be increased.

The schematic diagram which shows the meshing | engagement in case the backlash of the gearwheel which concerns on 1st Embodiment of this invention is zero. The schematic diagram which shows the setting method of the tooth top part connection point and tooth root part connection point of the gearwheel of 1st Embodiment. The schematic diagram which shows the shape determination method of the tooth tip part and tooth root part of the gearwheel of 1st Embodiment. The schematic diagram which shows the state which made all the tooth tip part and tooth base part of the gearwheel of 1st Embodiment into circular arc shape. The schematic diagram which shows the change of an engagement at the time of using the gearwheel of 1st Embodiment. The schematic diagram which shows the involute gear used as the basic view for producing the gear in case there exists backlash of 2nd Embodiment. The schematic diagram which shows the setting method of the tooth tip part connection point and tooth root part connection point of the gearwheel of 2nd Embodiment. The schematic diagram which shows the method of setting another tooth tip part connection point of the gearwheel of 2nd Embodiment. The schematic diagram which shows the shape determination method of the tooth tip part and tooth root part of the gearwheel of 2nd Embodiment. The schematic diagram which shows the state which made all the tooth tip part and tooth root part of the gearwheel of 2nd Embodiment into circular arc shape. The schematic diagram which shows the change by rotation of the confinement of the conventional involute gear.

  A first embodiment of the present invention will be described with reference to the drawings.

  <Outline of Gear of First Embodiment>

  The gear 100 according to the first embodiment is used in a fluid machine such as a gear pump, a flow meter, and a compressor. The fluid sucked and discharged by the gear 100 may be either liquid or gas. That is, the gear 100 according to the first embodiment is used for applications where fluid pulsation, noise, and vibration are problematic due to a change in volume of the confinement, and applications where high sealing performance is required such as when handling gas. Is.

  The gear 100 according to the first embodiment has no backlash and is formed as a helical gear. FIG. 1 shows a case where the number of teeth is four as the tooth profile appearing in the cross section. The outline of the tooth profile of the gear 100 will be described. The tooth tip portion 1 and the tooth root portion 2 are formed in an arc shape, and the portion between the tooth tip portion 1 and the tooth root portion 2 is a rotating meshing portion 3 by an involute curve. Is formed.

  In other words, the gear 100 according to the first embodiment has a tooth tip portion 1 that is formed symmetrically with respect to the tooth tip reference line L <b> 1 by an arc shape that protrudes outward, and is convex inward. The tooth base part 2 formed symmetrically with respect to the tooth base reference line L2 by the circular arc shape, and the rotation meshing part in which the rotation mesh formed by the involute curve is generated between the tooth tip part 1 and the tooth base part 2 3. As shown in FIG. 1 (a), the tooth profile is formed by repeating the tooth tip portion 1, the rotating mesh portion 3, the tooth root portion 2, and the rotating mesh portion 3 in this order. It is.

  Further, as shown in FIG. 1 (a), each curve is common in the tooth tip connection point P1, which is a connection point between the arc forming the tooth tip 1 and the involute curve forming the rotating mesh part 3. It is connected continuously and smoothly so as to have a tangent line. Similarly, at the tooth root portion connection point P2, which is a connection point between the arc forming the tooth root portion 2 and the involute curve forming the rotating meshing portion 3, each curve is continuously and smoothly so as to have a common tangent line. Connected.

  The characteristics of the gear 100 according to the first embodiment will be described. The gear 100 is formed as an involute curve as a profile in which the rotation mesh is generated, while the profile in which the rotation mesh is not generated. The tooth tip portion 1 and the tooth root portion 2 are formed in an arc shape. For this reason, as shown in FIG. 1B, when a pair of the gears 100 having the same shape is prepared and meshed with each other, the rotating meshing portion 3 is formed by an involute curve. Will move on the common tangent line L4 of the basic circle BC. For this reason, since the force applied to each gear 100 becomes a force in a direction along the common tangent line L4 of each basic circle BC, the meshing can be transmitted efficiently.

  <Design Method of Gear 100 of First Embodiment>

  In the following, the positions of the tooth tip connection point P1 and the tooth root connection point P2 in the gear 100 are set, and the gear design method will be described as to how to set the positions in the following. explain. In the following description, when it is necessary to distinguish the pair of gears 100, one gear is denoted by 100a, and the other gear is denoted by reference numeral 100b.

  First, as a preparation for designing the gear 100 of the present embodiment, the number of teeth, modules, and the like are determined in advance based on the required space between teeth, and all tooth forms having the corresponding number of teeth and modules are used. A pair of involute gears 100 as shown in FIG. 2A and FIG. 2B formed by involute curves is created as a reference diagram. At this time, various parameters may be set so that the tooth tip side is not cut down.

  Then, in order to change the shape of the tooth tip portion and the tooth root portion of the involute gear into an arc shape to obtain the gear 100 of the first embodiment, the tooth tip portion connection point P1 and the tooth root portion connection point P2 are set as follows. Determined by drawing or calculation.

  The tooth tip part connection point P1 and the tooth root part connection point P2 not only determine which region in the tooth profile the tooth tip part 1 and the tooth root part 2 are set as described above, but also the pair of pairs. In the meshing between the gears 100, the point at which the meshing is started and the point at which the meshing is finished are also determined.

  Specifically, as shown in FIG. 2, the pair of gears 100 are in mesh with each other, and when viewed from the axial direction, a center line L3 connecting the rotation axes of the gears 100 and one gear 100a. A state in which the tooth base reference line L2 coincides is drawn. In other words, it arrange | positions so that the trough part of the tooth | gear which is the said tooth root part 2 of said one gearwheel 100a may become left-right symmetric with respect to the said centerline L3.

  Further, in the first embodiment, since it is considered that each gear 100 does not have backlash, if the other gear 100b is engaged with one gear 100a, the tooth tip reference line L1 is the center. It is in a state consistent with the line L3.

  When the pair of gears 100 are arranged in this way, as shown in FIG. 2A, the gears 100 formed by involute curves are engaged on the common tangent line L4 of the base circle BC. The intersection of the involute curve and the common tangent L4 of each basic circle BC is the starting point of the meshing. Therefore, this intersection is set as one of the tooth root part connection point P2 in one gear 100a, and is set as one of the tooth tip part connection point P1 in the other gear 100b.

  Further, as shown in FIG. 2B, for example, when the auxiliary circle AC is drawn so as to pass through the intersection point from the rotation axis of each gear 100, a symmetrical point corresponding to the intersection point in the tooth tip portion 1 and the tooth root portion 2 is obtained. Can be set. By this operation, in one gear 100a, a point that is line symmetric with respect to the tooth root connection point P2 and the tooth root reference line L2 is found, and in the other gear 100b, the tooth tip connection point P1. And a point at a line-symmetrical position with respect to the tooth tip reference line L1. These points are also set as a tooth base connection point P2 and a tooth tip connection point P1, respectively.

  Note that the method of finding each symmetry point is not limited to the illustrated drawing method, and may be found by other methods.

  Thereafter, as shown in FIG. 3 (a), in one gear 100a, it passes through each tooth base connection point P2 and inward so as to have an involute curve and a common tangent line at these tooth base connection points P2. The shape of the tooth base connection point P2 is determined as a convex arc. In the other gear 100b, the shape of the tooth tip portion 1 is formed as an arc convex outward so as to pass through each tooth tip connection point P1 and to have an involute curve and a common tangent line at these tooth tip connection points P1. Is determined.

  The characteristics of the shape of the gear 100 designed in this way will be described. When there is no backlash as shown in FIG. 3B, the shapes of the tooth tip portion 1 and the tooth root portion 2 are the same arc shape. Will be set.

  Further, as shown in FIG. 3B, the arc shape of the tooth tip portion 1 is formed on the inner side as compared with the tooth tip portion in which all tooth shapes shown by dotted lines are formed by involute curves. The front part 1 is not involved in the meshing. Furthermore, as shown in FIG. 3 (b), the arc shape of the tooth root portion 2 is formed on the outer side compared to the tooth root portion in which all tooth shapes indicated by dotted lines are formed by involute curves, It can be seen that even when the number of teeth and the module are increased, the tooth base can be thickened and the strength can be maintained.

  Finally, when the shapes of the tooth tip portion 1 and the tooth root portion 2 obtained in FIG. 3 are developed on all teeth, the gear 100 of the first embodiment as shown in FIG. 4 can be obtained. Therefore, as shown in FIG. 1, the tooth tip connecting point P1 and the tooth root connecting point P2 are set at the meshing start point and meshing end point, and the rotational meshing formed by the involute curve only in the region where the meshing occurs. Part 3 can be used.

  <Change of meshing of gear 100 of the first embodiment>

  Furthermore, a change when the pair of gears 100 of the first embodiment is engaged and rotated will be described. As shown in FIG. 5, when the gears 100 of the first embodiment are meshed with each other, one place is always in contact with each other, and the tooth tip portion 1 and the tooth root portion 2 have the same shape and no meshing occurs. Since it is formed in an arc shape, it can be seen that no confinement has occurred. Therefore, even if the gears 100 are rotated, there is almost no confinement, and pulsation and noise are unlikely to occur. Further, since there is almost no gap V between the meshing teeth during rotation, a large force is hardly applied and a backflow is not easily generated.

  <Effects of Gear 100 of First Embodiment>

  As described above, according to the gear 100 of the first embodiment, only the region involved in the meshing is the rotational meshing portion 3 formed by the involute curve, and the tooth tip portion 1 and the tooth root portion 2 are formed in the same circular arc shape. Since it is formed so that no meshing occurs and the gap V does not substantially occur, pulsation, noise, vibration, etc. caused by the confinement hardly occur. Moreover, since there is almost no gap V and the sealing property is high, the fluid is a gas, and it can be used in applications that require accuracy such as a flow meter.

  Next, the gear 100 and the gear design method of the second embodiment will be described.

  <Outline of Gear 100 of Second Embodiment>

  The gear 100 according to the second embodiment takes into account the presence of backlash between the gears 100 to be engaged. Similarly to the gear 100 of the first embodiment, the tooth tip portion 1 and the tooth root portion 2 are formed in an arc shape, and the rotating meshing portion 3 in which meshing occurs is formed by an involute curve. On the other hand, the position of the tooth tip part connection point P1 and the position of the tooth root part connection point P2 are different from those of the first embodiment, and the shape of the tooth tip part 1 and the tooth root part connection point P2 is also different. It has a different curvature.

  <Method for Designing Gear 100 of Second Embodiment>

  Next, a gear design method when the backlash of the second embodiment is present will be described.

  Similar to the first embodiment, a gear 100 having all tooth shapes formed by involute curves is drawn, and as shown in FIG. 6 (a), for one gear 100a, the tooth base reference line L2 and the center line L3 are drawn. Are arranged so as to coincide with each other, and the tooth tip reference line L1 coincides with the center line L3 in a state where the other gear 100b has a predetermined backlash corresponding to the one gear 100a. Draw on. In this case, as shown in FIG. 6B, each gear 100 has no backlash, so that each gear 100 is not in contact.

  Next, as shown in FIG. 7, the other gear 100b is tilted by a predetermined angle a ° and brought into contact with the one gear 100a to draw a meshing state. At this time, the contact point of each gear 100 is on the common tangent L4 of each basic circle BC as shown in the enlarged view of FIG. 7B from the characteristics of the involute gear 100. This contact point is set as one of the tooth tip connection point P1 and the tooth root part connection point P2.

  Further, in order to find another tooth tip connection point P1 and tooth root part connection point P2, an auxiliary circle AC is drawn so as to pass through this contact point from the rotation shaft of each gear 100.

  Next, as shown in FIG. 8, the inclination of the other gear 100b is returned, and the tooth tip reference line L1 is made to coincide with the center line L3. In this state, as shown in the enlarged view of FIG. 8 (b), another intersection of the auxiliary circle AC and the involute curve different from the previously identified tooth tip connecting point P1 is another tooth tip connecting point. Set as P1.

  Since one gear 100a is not rotated or the like, the auxiliary circle AC, the involute curve, and the intersection point different from the tooth base connection point P2 specified earlier are not particularly operated, and the other tooth It is set as the original part connection point P2.

  Next, an arc is drawn so as to pass through each of the two tooth tip connection points P1 and the tooth root connection points P2 determined as shown in FIG. 9 and to have an involute curve and a common tangent line at each point. As shown in the enlarged view of FIG. 9B, when there is backlash, the arc of the tooth base portion 2 has a larger curvature than the arc of the tooth tip portion 1.

  In this way, the start and end positions of the tooth tip portion 1 and the tooth root portion 2 are determined, and the arc shape thereof is also specified. In addition, even when there is backlash in accordance therewith, the rotational meshing portion 3 formed by the involute curve is formed only at the portion where the meshing occurs.

  Finally, the shape of the tooth tip portion 1 and the tooth root portion 2 can be developed on all teeth to obtain a tooth profile as shown in FIG.

  As described above, according to the gear 100 and the gear design method of the second embodiment, only the portion where the meshing occurs even when the backlash exists is the rotational meshing portion 3 formed by the involute curve, and the meshing is performed. Since the tooth tip portion 1 and the tooth root portion 2 which are not generated can be formed in an arc shape, the confinement can be kept small while keeping the meshing transmission property.

  <Other embodiments>

  In the first embodiment and the second embodiment, another tooth tip part paired with the tooth tip part connection point and the tooth root part connection point determined from the intersection of the common tangent line of each foundation circle and the involute curve In order to set the connection point and the root part connection point, an auxiliary circle was drawn from the rotation axis of each gear. For example, the auxiliary circle is located symmetrically with respect to the tooth tip reference line and the tooth base reference line. You may set a point as a tooth tip part connection point and tooth root part connection point which become a pair.

  Further, when there is no backlash as in the first embodiment, two intersections between two common tangents of each basic circle and the involute curve are set as the tooth tip connection point and the tooth root connection point. You may do it. In short, when the troughs of the gears are arranged so as to be symmetric with respect to the center line, the tooth root connection point can be found by the intersection of the involute curve and the common tangent of each basic circle.

  In the said embodiment, although the shape of the tooth tip part and the tooth root part was a perfect circular arc, it may be formed by other ellipses or a part of a parabola. That is, the shape of the tooth tip portion and the tooth root portion may be defined by a quadratic curve.

  In general, since tolerance is set for backlash, if the arc shape of the tooth tip and root is drawn by the method described in this specification, the tolerance is also set for the arc shape. Will be.

  In addition, although the helical gear is used in the embodiment, the present invention may be used as other gears such as a spur gear. Further, the present invention is not limited to the number of teeth and modules described in each embodiment, and other specifications can be applied.

  In addition, what is necessary is just to manufacture the rack which can form circular arc shape and an involute curve, when manufacturing this gear. A gear that requires gear accuracy can be manufactured by gear grinding.

100: gear 1: tooth tip part 2: tooth root part 3: part 100: involute gear AC: auxiliary circle BC: basic circle L1: tooth tip reference line L2: tooth root reference line L3: center line L4: common tangent line P1: Tooth tip connecting point P2: Tooth base connecting point V: Gap

Claims (3)

The tooth profile is symmetrical with respect to the tooth root reference line by the quadratic curve convex outward and symmetrical with respect to the tooth root reference line by the secondary curve convex inward. And a rotation meshing portion in which a rotation mesh formed by an involute curve is formed between the tooth tip portion and the tooth root portion.
The tooth tip portion, the rotation meshing portion, the tooth root portion, the rotation meshing portion is a gear having a tooth profile configured by repeating in this order,
In a state where the pair of gears are in mesh with each other, and when viewed from the axial direction, the center line connecting the rotation shafts of the respective gears and the tooth base reference line of one gear coincide with each other.
The point of intersection of the involute curve forming the rotating meshing portion of each gear and the common tangent of the basic circle of each gear is the connecting point of the tooth tip portion and the rotating meshing portion of the other gear; , Is set to a tooth root part connection point that is a connection point between the rotation meshing part and the tooth root part in one gear,
The quadratic curve forming the tooth tip part passes through the point at the tooth tip part connecting point and the tooth tip part connecting point and the tooth tip reference line, and each rotation meshes at each point. Are connected so as to have a common tangent with the involute curve forming the part,
The quadratic curve forming the tooth root part passes through the tooth root connection point and a point that is line-symmetric with respect to the tooth root connection point and the tooth root reference line, and each rotation meshes at each point. Are connected so as to have a common tangent with the involute curve forming the part,
Ri Thea forming the addendum portion and the tooth root portion in a quadratic curve having substantially the same shape,
A backlash exists between the pair of gears,
A gear having a contact point when the other gear is rotated to come into contact with one gear is set as the tooth tip connection point . The tooth profile is symmetrical with respect to the tooth root reference line by the quadratic curve convex outward and symmetrical with respect to the tooth root reference line by the secondary curve convex inward. And a rotation meshing portion in which a rotation mesh formed by an involute curve is formed between the tooth tip portion and the tooth root portion.
A gear design method for a gear in which a tooth form is configured by repeating the tooth tip portion, the rotation meshing portion, the tooth root portion, and the rotation meshing portion in this order,
A gear arrangement step for causing the pair of gears to mesh with each other, and when viewed from the axial direction, the center line connecting the rotation shafts of the gears and the tooth base reference line of one gear coincide with each other. When,
The intersection of the involute curve forming the rotating meshing portion of each gear and the common tangent of the basic circle of each gear, and the tooth tip connecting point that is the connecting point of the tooth tip portion and the rotating meshing portion of the other gear, A connection point setting step for setting to a tooth root part connection point that is a connection point between the rotation meshing part and the tooth root part in one gear;
It has an involute curve and a common tangent line that pass through the tooth tip connection point and a point that is line-symmetric with respect to the tooth tip connection point and the tooth tip reference line, and form each rotation meshing portion at each point. A tooth tip forming step for forming the tooth tip portion by a quadratic curve connected to
It has an involute curve and a common tangent line that pass through the tooth base connection point and the tooth base connection point and a point that is line-symmetric with respect to the tooth base reference line, and forms each rotation meshing portion at each point. A tooth root portion forming step, wherein the tooth root portion is formed by a quadratic curve connected to the tooth portion, and the shape of the tooth root portion and the tooth tip portion is formed by a quadratic curve having substantially the same shape Gear design method. A backlash exists between the pair of gears,
The gear design method according to claim 2 , wherein a contact point when the other gear is rotated to come into contact with one gear is set as the tooth tip connection point.