JP2011174558A - Method of automatically matching worm phase - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of automatically matching a worm phase, efficiently performing attaching processes in a short time at low cost without damaging both worm and worm wheel by automatically matching the phases of teeth and grooves thereof with each other at the same time when a series of attaching processes for attaching the worm to the worm wheel. <P>SOLUTION: The method includes inserting the teeth of the worm into the grooves 4c of the worm wheel while rotating the worm wheel by partially meshing the teeth 2b, 4b of both worm and worm wheel based on a detection result that there is no reaction force from the worm wheel during rotating the worm and simultaneously moving the worm along its rotation axis Ax1 while applying pressing force to the worm for moving it in parallel toward the worm wheel in a condition that the worm is moved in parallel until the tooth tips of the worm 2 adjoin the maximum outer diameter of the tooth tips of the worm wheel 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, for example, in an existing worm gear used for electric steering and various transmissions, when a worm (screw gear) is assembled to a worm wheel (helical gear), both teeth (ridges) and grooves ( Tanibe) The present invention relates to a warm phase automatic alignment method for automatically adjusting the mutual phases.

  Conventionally, various techniques for assembling a worm (screw gear) to a worm wheel (helical gear) are known. For example, in Patent Document 1, when the worm and the worm wheel interfere with each other during the assembly process and a predetermined slip occurs between the worm and the device that rotates the worm, the meshing state of the worm and the worm wheel is changed. After that (that is, after phase matching between both tooth portions (peak portions) and groove portions (valley portions)), a technique for performing the assembly process again is shown.

  Further, for example, Patent Document 2 discloses that tooth portions (mountain portions) of both the worm and the worm wheel so that initial contact between the worm and the worm wheel occurs between the respective tooth portions (peak portions) during the assembling process. ) And the groove (valley) are phase-matched, and then a technique for performing the assembly process is shown.

  By the way, in both of the techniques disclosed in Patent Documents 1 and 2 described above, in addition to a series of assembly processes for assembling the worm to the worm wheel, the phase alignment between both tooth portions (peak portions) and groove portions (valley portions) is performed. Since it must be performed, it is troublesome and cumbersome, and the assembly process between the worm and the worm wheel becomes complicated, and there is a certain limit to the efficiency of the assembly process. Further, depending on the complexity of the assembling process, it takes time for the assembling process, and the cost required for the assembling process increases accordingly. Furthermore, the worm and the worm wheel are caught during phase alignment, and depending on the degree, both may be damaged.

JP-A-11-267932 JP-A-9-49552

  The present invention has been made to solve the above-described problems, and its purpose is to automatically phase align both teeth and grooves simultaneously in a series of assembly processes for assembling a worm to a worm wheel. Thus, it is an object of the present invention to provide a worm phase automatic alignment method capable of performing an assembly process efficiently and at low cost in a short time without damaging both the worm and the worm wheel.

In order to achieve this object, the present invention provides a worm phase automatic alignment method capable of automatically aligning the phases of both teeth and grooves when a worm is assembled to a worm wheel. The first step of positioning the worm wheel at the initial translation position facing the worm wheel, and the worm is translated from the translation initial position toward the worm wheel until the tooth tip of the worm is adjacent to the maximum outer diameter of the tooth tip of the worm wheel. Then, in the second step of positioning at the phase alignment start position and the state where the worm is positioned at the phase alignment start position, the pressing force for translating toward the worm wheel while rotating the worm about its rotation axis at the same time Is applied to the worm and the worm is moved in parallel along the rotation axis by a minimum amount of movement. And the fourth step of detecting the presence or absence of reaction force from the worm wheel generated in the worm by the pressing force applied to the worm when the worm is moved by the minimum movement amount, and during the movement of the worm by the minimum movement amount In addition, based on the result of detection that there is no reaction force detected at least once, the worm is rotated and simultaneously translated toward the worm wheel, and the worm tooth tip is partially inserted into the groove of the worm wheel. By doing so, the fifth step of partially engaging the teeth of both the worm and the worm wheel, and transmitting the rotational movement of the worm to the worm wheel via the partially engaged teeth, the worm wheel is rotated. Then, move the worm further toward the worm wheel and fully insert the worm teeth into the groove of the worm wheel. And a sixth step of.
In the present invention, in the third step, when the rotation angle of the worm is θ, the circumferential length of the tooth portion of the worm wheel is L, and the pitch of the tooth portion of the worm is P, the worm is parallel to the rotation axis. The minimum amount of movement Zm when moving is
P1 + Zm ≧ L
P1 = P × (θ / 360 °)
P1: It is set so as to satisfy the relationship of the advance amount of the tooth portion when the worm rotates by the angle θ.
In the present invention, in the fifth step, while the worm is rotated, at the same time, the amount of movement when parallelly moving toward the worm wheel is adjacent along the diameter up to the tip of the tooth tip centered on the rotation axis of the worm wheel. The difference between the tooth portions in alignment along the parallel movement direction of the worm is defined as the minimum movement amount, and the worm is translated toward the worm wheel beyond the minimum movement amount.

  According to the present invention, during a series of assembly processes for assembling the worm to the worm wheel, both the teeth and the groove are automatically phase-matched without damaging both the worm and the worm wheel. Thus, it is possible to realize a warm phase automatic alignment method capable of performing the assembly process efficiently in a short time and at low cost.

FIG. 5 is a diagram showing an assembly process of a worm gear to which an automatic worm phase alignment method according to an embodiment of the present invention is applied, wherein (a) is a diagram showing a state where a worm is inserted into a gear box; ) Is a diagram showing a state in which the worm is positioned at the horizontal movement initial position, (c) is a diagram showing a partially enlarged state in which the worm is positioned at the phase alignment start position, and (d) Figure (e) is a partially enlarged view of the state where both teeth and grooves are phase aligned while simultaneously rotating vertically while rotating. The figure which expands and shows the assembled state partially. (a) is a partially enlarged view showing the positional relationship between the worm and the worm wheel at the initial horizontal movement position when the phase alignment start position is the tooth portion of the worm wheel, and (b) is the phase alignment start position. In the case of the groove portion of the worm wheel, a diagram showing a partially enlarged positional relationship between the worm and the worm wheel at the initial horizontal movement position, (c) is a diagram showing a partially enlarged configuration of the worm wheel, (d) FIG. 5 is a partially enlarged view showing the configuration of the worm, and FIG. 5E is a partially enlarged view showing the configuration for setting the horizontal movement amount of the worm. (a) is a partially enlarged view showing the arrangement configuration when the phase alignment start position is the tooth portion of the worm wheel, and (b) is a state in which the worm is simultaneously moved vertically downward while rotating. A partially enlarged view, (c) is a partially enlarged view showing a state in which the worm tooth tip is opposed to the worm wheel groove, and (d) is a worm tooth tip in the worm wheel groove. The figure which expands and shows the state which is inserting partially. (a) is a partially enlarged view showing the arrangement configuration in the case where the phase alignment start position is the groove portion of the worm wheel, and (b) is a state in which the worm tooth tip is inserted into the groove portion of the worm wheel. The figure which expands and shows a part.

Hereinafter, a worm phase automatic alignment method according to an embodiment of the present invention will be described with reference to the accompanying drawings.
In this embodiment, for example, in an existing worm gear used for electric steering and various transmissions, when a worm (screw gear) is assembled to a worm wheel (helical gear), both teeth (ridges) and grooves (Tanibe) A worm phase automatic alignment method capable of automatically adjusting the phases of each other is assumed.

  In addition, in the worm phase automatic alignment method of the present embodiment, a commercially available existing worm gear can be used as it is for the worm and the worm wheel. For this reason, the size, shape, material, etc. of the worm and worm wheel are not particularly limited here, but in the following embodiment, as an example of the worm gear, the metal made for general electric steering and various transmissions is used. Worm and resin worm wheel are assumed.

  As shown in FIGS. 1A to 1C, the worm 2 includes one columnar worm shaft 2a rotatably supported by a drive mechanism (not shown) incorporating a computer or the like. On the outer periphery of the shaft 2a, one tooth portion (mountain portion) 2b is continuously formed in a spiral shape around the rotation axis Ax1. In this case, a spiral groove portion (valley portion) 2c is continuously interposed between the spiral tooth portions (peak portions) 2b around the rotation axis Ax1.

  In addition, both the cases where the helical pitch of the tooth part (mountain part) 2b around the worm shaft 2a is set to be the same or randomly are assumed. In the case of the helical tooth portion (mountain portion) 2b, this is called a worm tooth (worm portion), and in the case of the helical groove portion (valley portion) 2c, this is called a worm groove (warm valley). In the following, the worm teeth 2b and the worm grooves 2c will be referred to.

  On the other hand, the worm wheel 4 includes a disc-shaped wheel body 4a that is rotatably supported by a drive mechanism (not shown) incorporating a computer or the like. The wheel body 4a has a rotation axis Ax2 as a center. A plurality of tooth portions (mountain portions) 4b having the same diameter are formed at predetermined intervals (for example, equal intervals) along the outer periphery. In this case, a plurality of groove portions (valley portions) 4c having the same diameter around the rotation axis Ax2 are interposed between the plurality of tooth portions (peak portions) 4b at a predetermined interval (for example, at equal intervals). .

  In addition, about the several tooth part (mountain part) 4b, these are also called a wheel tooth (wheel crest), and about the some groove part (valley part) 4c, these may be called a wheel groove (wheel trough). However, in the following, they are referred to as wheel teeth 4b and wheel grooves 4c.

  The worm 2 is assembled to the worm wheel 4 by matching the phases of the worm teeth 2b and the wheel grooves 4c (in other words, the phases of the worm grooves 2c and the wheel teeth 4b) (see FIG. 1 (e)), the rotational motion can be decelerated and transmitted from the worm 2 to the worm wheel 4, and conversely, the rotational motion can be transmitted from the worm wheel 4 to the worm 2 at an increased speed. Can do.

  Here, when the worm 2 is assembled to the worm wheel 4, the worm phase automatic alignment method for automatically matching the phase between the worm tooth 2b and the wheel groove 4c (the phase between the worm groove 2c and the wheel tooth 4b). explain. In the following description, it is assumed that the worm 2 is assembled to the worm wheel 4 that is set in the rotation free state in the existing gear box 6. In the assembly process, as an example, the horizontal movement (X axis) of the worm 2 is performed by a commercially available vertical multi-indirect robot (not shown) that supports three axes (X axis, Z axis, and rotation axis), The vertical downward movement (Z axis) and the rotational movement (rotation axis) are controlled.

  First, the worm 2 is moved along the vertical downward direction (Z-axis) and inserted into the gear box 6 (FIG. 1A), and the worm 2 is separated from the worm wheel 4 (ie, the worm 2 is separated from the worm wheel 4). It arrange | positions in the position which does not interfere (FIG.1 (b)). At this time, the worm 2 is positioned and arranged so that the worm teeth 2b (worm grooves 2c) of the worm 2 face the wheel grooves 4c (wheel teeth 4b) of the worm wheel 4 (including the meanings of facing and facing each other). . Specifically, the worm 2 is positioned so that the rotation axis Ax1 thereof is orthogonal to the rotation axis Ax2 of the worm wheel 4, and at the same time, the rotation axis Ax1 and the rotation axis Ax2 are orthogonal to each other and the respective rotations are performed. Positioning and positioning are performed on one axis (X axis: see FIGS. 2A and 2B) penetrating the axes Ax1 and Ax2.

  In this state, the worm 2 is positioned at a parallel (horizontal) movement initial position. The parallel (horizontal) movement initial position can be defined as the coordinates on the X axis. In this case, an assembly process (initial position coordinate defining process) until the worm 2 is positioned at the parallel (horizontal) movement initial position and defined as coordinates on the X axis is provided in a vertical multi-indirect robot (not shown). In the computer, an initial position coordinate defining program stored in a ROM (not shown) is executed by a CPU (not shown) using a RAM (not shown) as a work area.

  Thereafter, the worm 2 is moved in parallel (horizontal) toward the worm wheel 4 along the horizontal direction (X axis) from the initial position of parallel (horizontal) movement. Specifically, the worm 2 is parallel from the initial position of parallel (horizontal) movement toward the worm wheel 4 until the tooth tip of the worm 2 (worm tooth 2b) is adjacent to the tooth tip maximum outer diameter T of the worm wheel 4. Move (horizontal) to position at the phase alignment start position.

  The tooth tip of the worm 2 (worm tooth 2b) is defined as the maximum outer diameter S of the worm 2 (worm tooth 2b) around the rotation axis Ax1 of the worm 2. Specifically, assuming that one imaginary plane orthogonal to the rotation axis Ax1 of the worm 2 is assumed, the maximum outer diameter S is one worm tooth 2b configured continuously in a spiral shape along the worm shaft 2a. Among the tooth tips, the value on the virtual plane between the tooth tip located on the virtual plane and the rotation axis Ax1 (ie, radius: S / 2), that is, the rotation axis Ax1 It is defined as the diameter (S) of the worm 2 at the center.

  The maximum tooth tip outer diameter T of the worm wheel 4 is defined as the diameter of the wheel tooth 4b up to the tip of the tooth tip with the rotation axis Ax2 of the worm wheel 4 as the center. Specifically, the tooth tip maximum outer diameter T is one imaginary configured by connecting tip end tips of a plurality of wheel teeth 4b configured along the outer periphery of the wheel body 4a to each other along the outer periphery. It is defined as the diameter of the circle, that is, the tip circle diameter (T) of the worm wheel 4 around the rotation axis Ax2.

Thus, by moving the worm 2 in parallel (horizontal) from the parallel (horizontal) movement initial position described above, the worm 2 is positioned at the phase alignment start position (FIG. 1 (c)).
Here, the movement amount (movement distance) by which the worm 2 is moved in parallel (horizontal) from the parallel (horizontal) movement initial position to the phase alignment start position will be described with reference to FIGS. 2 (a) and 2 (b).

  2 (a) and 2 (b) show an X axis that defines the parallel (horizontal) movement amount (movement distance) of the worm 2 and a Z axis that is orthogonal to the X axis. The Z axis defines the vertical movement amount (vertical movement distance) of the worm 2 described later. In this case, the X-axis rotates with the rotation axis Ax1 and the rotation axis Ax1 in a state where the rotation axis Ax1 of the worm 2 is orthogonal to the rotation axis Ax2 of the worm wheel 4 at the initial position of the parallel (horizontal) movement described above. It is defined as one axis that is orthogonal to both of the axes Ax2 and passes through the respective rotation axes Ax1 and Ax2.

  By the way, depending on the set position (rotation state) of the worm wheel 4 in the gear box 6, the tooth tip of the worm 2 (worm tooth 2 b) corresponds to the wheel tooth 4 b of the worm wheel 4 at the phase alignment start position. When positioned adjacent to the maximum outer diameter T (FIG. 2A), or the tooth tip of the worm 2 (worm tooth 2b) has a tooth tip maximum outer diameter T corresponding to the wheel groove 4c of the worm wheel 4. The case where it positions adjacently (FIG.2 (b)) is assumed.

  In any case, of the two intersections of the tooth tip maximum outer diameter T of the worm wheel 4 and the X axis, the maximum outer diameter point Tmax on the worm 2 side and the maximum outer diameter S of the worm 2 (worm tooth 2b). By calculating an absolute value (| Smax−Tmax |) that is the difference between the maximum outer diameter point Smax on the worm wheel 4 side between the two intersections of the worm and the X axis, the parallel (horizontal) movement amount of the worm 2 ( Movement distance) M can be set. The difference calculation process is executed by a CPU in a computer provided in the vertical multi-indirect robot using a difference calculation process program stored in the ROM with the RAM as a work area.

  Then, the worm 2 is moved from the parallel (horizontal) movement initial position to the worm wheel 4 along the horizontal direction (X axis) by the movement amount M corresponding to (matching) the absolute value obtained through the difference calculation process. The worm 2 can be positioned at the optimum phase alignment start position by moving in a parallel (horizontal) direction (FIG. 1 (c)). The movement process is executed by a CPU in a computer provided in the vertical multi-indirect robot using a movement process program stored in the ROM with the RAM as a work area.

  Subsequently, as shown in FIG. 1D, in a state where the worm 2 is positioned at the phase alignment start position, the worm 2 is rotated toward the worm wheel 4 at the same time while rotating the worm 2 about the rotation axis Ax1 in the predetermined direction R. The worm 2 is moved in parallel along the rotation axis Ax1 (specifically, in the vertical downward direction (Z axis)) while applying a pressing force to the worm 2 in parallel. The movement process is executed by a CPU in a computer provided in the vertical multi-indirect robot using a movement process program stored in the ROM with the RAM as a work area.

  In this case, the rotational speed at the time of rotating the worm 2 is set to an optimum value according to the size, shape, etc. of the worm 2 and the worm wheel 4, and is not particularly limited here. Further, regarding the pressing force for translating the worm 2 toward the worm wheel 4, when the tooth tip of the worm 2 (worm tooth 2 b) is pressed against the wheel teeth 4 b of the worm wheel 4 by the pressing force, The wheel teeth 4b and other parts of the worm wheel 4 are automatically adjusted by the pressure contact force so as not to be damaged by the tooth tips of the worm teeth 2b. In this case, the degree (strength) of the pressing force (pressure contact force) is automatically adjusted to an optimum value according to the material, size, etc. of the worm 2 and the worm wheel 4, and is not particularly limited here.

Here, FIGS. 2C and 2D show the movement amount when the worm 2 is moved in parallel along the rotation axis Ax1 (specifically, along the vertical downward direction (Z-axis)). The description will be given with reference.
The amount of movement takes into account the relationship between the rotation angle when rotating the worm 2, the individual circumferential lengths of the plurality of wheel teeth 4 b, and the helical pitch of the worm teeth 2 b continuously spirally around the worm shaft 2 a. Is set.

Specifically, when the rotation angle of the worm 2 is θ (°), the individual circumferential lengths of the wheel teeth 4b are L (mm), and the helical pitch of the worm teeth 2b is P (mm), the worm 2 is vertical. The minimum movement amount Zm when moving in parallel along the downward direction (Z axis) is set so as to satisfy the following relationship. P1 indicates the amount of advance along the vertical downward direction (Z-axis) of the worm tooth 2b when the worm 2 rotates by an angle θ.
P1 + Zm ≧ L
P1 = P × (θ / 360 °)

  Further, when the worm 2 moves in the vertical downward direction (Z axis) satisfying the above relationship, the presence or absence of reaction force from the worm wheel 4 generated in the worm 2 is detected by the pressing force applied to the worm 2. Is done. In this case, while the worm 2 is moved vertically downward (Z axis) by the minimum movement amount Zm in accordance with the above-described relationship, the tooth tip of the worm 2 (worm tooth 2b) is moved to the wheel of the worm wheel 4 at least once. Opposite the groove 4c. At this time, “no reaction force” is detected, and based on the detection result, the worm 2 is rotated in the predetermined direction R around the rotation axis Ax1 and simultaneously moved toward the worm wheel 4.

  In this case, regarding the detection of the presence or absence of reaction force from the worm wheel 4, a reaction force detection processing program stored in the ROM is executed by the CPU using the RAM as a work area in a computer provided in the vertical multi-indirect robot. Further, when the worm 2 is translated toward the worm wheel 4 when it is detected that “no reaction force”, the worm 2 is moved by using the pressing force applied to the worm 2 as it is. You may make it translate toward the worm wheel 4, or you may make it raise the parallel movement speed of the said worm 2 by raising a pressing force further.

  Here, while detecting the reaction force from the worm wheel 4 and moving the worm 2 in the vertical downward direction (Z-axis) satisfying the above relationship, the worm 2 is detected based on the detection result “no reaction force”. The process of parallel translation toward the worm wheel 4 while rotating the wheel will be specifically described with reference to FIGS. 3 (a) to 3 (d) and FIGS. 4 (a) and 4 (b). The reaction force detection movement process is executed by the CPU in a computer provided in the vertical multi-indirect robot, with the reaction force detection movement process program stored in the ROM as a work area.

  First, as shown in FIGS. 3A to 3D, the tooth tip of the worm 2 (worm tooth 2 b) has a tooth tip maximum outer diameter T corresponding to the wheel tooth 4 b of the worm wheel 4 at the phase alignment start position. When it is positioned adjacent to (a) of the figure, it is detected that “there is a reaction force” from the worm wheel 4. Therefore, based on the detection result, while simultaneously rotating the worm 2, the worm 2 is moved vertically downward (Z-axis) by the minimum movement amount Zm satisfying the above relationship ((b) in the figure). At this time, the tooth tip of the worm 2 (worm tooth 2b) slides in a state of being pressed against the tooth surface of the wheel tooth 4b. However, the pressure contact force is automatically set to the optimum value as described above. Therefore, the tooth surface of the wheel tooth 4b is not damaged at the tooth tip of the worm 2.

  Then, while the worm 2 is moved by the minimum movement amount Zm, the tooth tip of the worm 2 (worm tooth 2b) faces the wheel groove 4c of the worm wheel 4 ((c) in the figure). At this time, “no reaction force” is detected. In synchronization with this, based on the detection result, the worm 2 is rotated and simultaneously translated toward the worm wheel 4, and the tooth tip of the worm 2 is inserted into the wheel groove 4c of the worm wheel 4 (same as above). (D).

  On the other hand, as shown in FIGS. 4A and 4B, the tooth tip of the worm 2 (worm tooth 2 b) has a tooth tip maximum outer diameter T corresponding to the wheel groove 4 c of the worm wheel 4 at the phase alignment start position. When it is positioned opposite to (a) of the figure, it is detected that there is no reaction force from the worm wheel 4. In this case, based on the detection result, the worm 2 is rotated and simultaneously translated toward the worm wheel 4, and the tooth tip of the worm 2 is inserted into the wheel groove 4c of the worm wheel 4 (same figure). (b))

Here, when it is detected that “no reaction force” is detected, the worm 2 is moved in parallel toward the worm wheel 4 and the tooth amount of the worm 2 is inserted into the wheel groove 4 c of the worm wheel 4. This will be described with reference to FIG.
In this case, the moving amount is adjacent to the tooth tip maximum outer diameter T of the worm wheel 4 (that is, the diameter of the wheel tooth 4b centering on the rotation axis Ax2 of the worm wheel 4 to the tip of the tooth tip). A difference Xm along the horizontal direction of the teeth 4b (X axis: the direction of translation of the worm 2) is defined as the minimum movement amount.

  Then, the tooth tip of the worm 2 (worm tooth 2b) is reliably inserted into the wheel groove 4c of the worm wheel 4 by translating the worm 2 toward the worm wheel 4 exceeding the minimum movement amount Xm. Can be made. From another viewpoint, the tooth tip of the wheel tooth 4b of the worm wheel 4 is inserted into the worm groove 2c of the worm wheel 2 by translating the worm 2 toward the worm wheel 4 exceeding the minimum movement amount Xm. Can be reliably inserted. At this time, the teeth 2b, 4b of both the worm 2 and the worm wheel 4 are partially engaged, specifically, the tooth tip of the worm 2 (worm tooth 2b) and the tooth tip of the wheel tooth 4b of the worm wheel 4. Are in mesh with each other.

  In this state, since the worm 2 continues to rotate, the rotational motion at this time is transmitted from the tooth tip of the worm 2 (worm tooth 2b) to the tooth tip of the wheel tooth 4b of the worm wheel 4 and is free to rotate. The worm wheel 4 in the state is rotated. As a result, the worm 2 can be translated toward the worm wheel 4 beyond the minimum movement amount Xm, so that the worm teeth 2b are placed in the wheel groove 4c (in other words, in the worm groove 2c). The wheel teeth 4b can be inserted smoothly and smoothly (see FIG. 1 (e)).

  At this time, by stopping the parallel movement of the worm 2 to the worm wheel 4, the phases of the worm teeth 2 b and the wheel grooves 4 c (in other words, the phases of the worm grooves 2 c and the wheel teeth 4 b) are matched. Is completed. The phase alignment final processing is executed by the CPU using a RAM provided as a work area in a phase alignment final processing program stored in the ROM in a computer provided in the vertical multi-indirect robot.

  Thus, in a state where the phase alignment is completed, one end of the worm 2 is rotatably supported by the bearing 8 (see FIGS. 1A and 1B). This makes it possible to transmit the rotational motion from the worm 2 to the worm wheel 4 while decelerating and transmitting the rotational motion from the worm wheel 4 to the worm 2 on the contrary. become.

  As described above, according to the worm phase automatic alignment method of the present embodiment, at the time of a series of assembling processes for assembling the worm 2 to the worm wheel 4, the phase between both teeth and grooves, that is, the worm teeth 2 b and the wheel grooves. The phase with 4c (the phase between the worm groove 2c and the wheel teeth 4b) can be automatically adjusted. Thereby, the efficiency of the assembly process of the worm 2 and the worm wheel 4 can be further improved.

  Moreover, since the time required for the assembly process can be shortened by improving the efficiency of the assembly process in this way, the assembly process of the worm 2 and the worm wheel 4 is required accordingly. Cost can be greatly reduced.

  Further, according to the worm phase automatic alignment method of the present embodiment, in the above-described final phase alignment process, the assembly process of the worm 2 and the worm wheel 4 is performed while the worm wheel 4 is rotated by the rotational motion of the worm 2. Therefore, the situation where the worm and the worm wheel are caught does not occur at all. Thereby, the worm 2 can be safely and reliably assembled to the worm wheel 4 without damaging both the worm 2 and the worm wheel 4.

2 Worm 2a Worm shaft 2b Worm tooth (tooth part)
2c Worm groove (groove)
4 Worm wheel 4a Wheel body 4b Wheel teeth (tooth part)
4c Wheel groove (groove)
Ax1 Worm rotation axis Ax2 Worm wheel rotation axis

Claims (3)

When assembling the worm to the worm wheel, it is a worm phase automatic alignment method capable of automatically adjusting the phases of both teeth and grooves.
A first step of positioning the worm at a translational initial position opposite the worm wheel;
A second step in which the worm is translated from the initial translation position toward the worm wheel until the tooth tip of the worm is adjacent to the maximum outer diameter of the tooth tip of the worm wheel, and is positioned at the phase alignment start position;
While the worm is positioned at the phase alignment start position, the worm is rotated about its rotation axis, and at the same time, a pressing force is applied to the worm to translate it toward the worm wheel, while the worm is rotated on its rotation axis. A third step of moving in parallel by a minimum amount of movement along
A fourth step of detecting the presence or absence of reaction force from the worm wheel generated in the worm by the pressing force applied to the worm when the worm is moved by the minimum movement amount;
While moving the worm by the minimum movement amount, based on the detection result that there is no reaction force detected at least once, while rotating the worm and simultaneously moving it toward the worm wheel, Is inserted into the groove portion of the worm wheel, the fifth step of partially engaging the teeth of both the worm and the worm wheel;
The rotational movement of the worm is transmitted to the worm wheel via the mutually engaged teeth, and the worm is rotated parallel to the worm wheel while rotating the worm wheel, and the worm teeth are moved to the worm wheel. And a sixth step of completely inserting into the groove of the worm phase. In the third step, assuming that the rotation angle of the worm is θ, the circumferential length of each tooth portion of the worm wheel is L, and the pitch of the tooth portion of the worm is P, the worm is moved in parallel along its rotation axis. The minimum movement amount Zm is
P1 + Zm ≧ L
P1 = P × (θ / 360 °)
2. The worm phase automatic alignment method according to claim 1, wherein P1 is set so as to satisfy the relationship of the advance amount of the tooth portion when the worm rotates by an angle θ.   In the fifth step, the amount of movement when the worm is rotated and translated toward the worm wheel at the same time is determined between the adjacent tooth portions along the diameter up to the tip of the tooth tip centered on the rotation axis of the worm wheel. The difference along the parallel movement direction of the worm is defined as a minimum movement amount, and the worm is translated toward the worm wheel beyond the minimum movement amount. Automatic warm phase alignment method.

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