JP7614495B2 - Planetary gear mechanism - Google Patents

Description

The present invention relates to a planetary gear mechanism having a sun gear, multiple planetary gears, and an internal gear.

It is well known that planetary gear mechanisms are used in drive devices (see, for example, Patent Document 1). In a planetary gear mechanism, multiple planetary gears are attached to a carrier, and a plate is attached to prevent the gears from falling off. This means that the planetary gears are sandwiched between the carrier and the plate.

JP 2017-25832 A

In a typical planetary gear mechanism, multiple planetary gears are arranged at equal intervals within the internal gear (equally spaced). In the case of even spacing, the positions of the pins that support the planetary gears on the carrier are also evenly spaced. Therefore, when machining the pins of the carrier, positioning can be done using any pin as a reference. Also, the plate has holes that fit with the pins of the carrier, and any pin can be used as a reference when assembling it.

However, depending on the design, multiple planetary gears may be arranged at unequal intervals within the internal gear (unequal spacing). In cases of unequal spacing, the spacing between the multiple pins of the carrier will have long and short sides. Furthermore, the material for the carrier is generally die-cast or forged to have a shape that requires minimal processing in order to be economical, and in cases of unequal spacing, the pins in the material will also be unevenly spaced. Therefore, when processing the pins on a carrier with unequal spacing, if the carrier is positioned in the wrong direction, the pins cannot be cut or ground correctly, resulting in processing defects.

When assembling, if the positioning direction of the unevenly spaced carriers or unevenly spaced plates is incorrect, the pins and holes will not match up, making it impossible to fit them together. This can lead to concerns that assembly will be difficult when fitting the plates.

In view of these problems, the present invention aims to provide a planetary gear mechanism that can accurately position the carrier during processing, even when multiple planetary gears are unevenly spaced, and can easily position the plate when assembling the carrier.

To solve the above problems, a typical configuration of the planetary gear mechanism according to the present invention is a planetary gear mechanism having a sun gear, multiple planetary gears, and an internal gear, the multiple planetary gears are arranged unequally around the sun gear, the mechanism has a carrier having multiple pins in the same number as the multiple planetary gears that support the multiple planetary gears, and a carrier-side marker for identifying the phase of the carrier is provided on the end face of each pin other than one of the multiple pins.

The above configuration allows the carrier-side marker to be reliably detected and, based on this, the even/uneven distribution and phase of the carriers can be determined. This allows the pins to be machined accurately, making it possible to prevent machining defects and deterioration of machinability.

The carrier-side marker may be a recess on the end face of the pin. This configuration makes it possible to easily form and detect the carrier-side marker.

A plate is attached to the opposite side of the carrier to prevent the planetary gear from falling off, and the plate has two plate-side markers for identifying the phase of the plate relative to the carrier, and the two plate-side markers are preferably positioned at the two vertices of a triangle centered on the axis of the sun gear. With this configuration, it is possible to determine whether the plates are evenly distributed or not, and the phase.

The present invention provides a planetary gear mechanism that can accurately position the carrier during processing, even when multiple planetary gears are unevenly spaced, and can easily position the plate when assembling the carrier.

FIG. 2 is an exploded perspective view illustrating the planetary gear mechanism according to the embodiment. 1A and 1B are a front view and a partial cross-sectional view illustrating a planetary gear mechanism according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an arrangement of planetary gears in a planetary gear mechanism. FIG. 13 is a diagram illustrating detection of a carrier-side marker. FIG. 13 is a diagram illustrating a comparative example in detection of a carrier-side marker. FIG. 13 is a diagram illustrating detection of a plate-side marker.

The preferred embodiment of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific values shown in the embodiment are merely examples to facilitate understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements that have substantially the same function and configuration are given the same reference numerals to avoid duplicated explanations, and elements that are not directly related to the present invention are not illustrated.

Figures 1 and 2 are diagrams illustrating the planetary gear mechanism 100 according to this embodiment. Figure 1 is an overall perspective view of the planetary gear mechanism 100 with each component disassembled. Figure 2(a) is a front view of the planetary gear mechanism 100 with all components assembled, observed from the plate 150 side, and Figure 2(b) is a cross-sectional view taken along line A-A in Figure 2(a).

As shown in FIG. 1 and FIG. 2(a) and (b), the planetary gear mechanism 100 of this embodiment includes a carrier 110, three planetary gears 120, a sun gear 130, an internal gear 140, and a plate 150. Note that, although this embodiment illustrates an example of the planetary gear mechanism 100 having three planetary gears 120, this is not limiting, and the number of planetary gears 120 can be changed as desired.

The carrier 110 has a base material 112 and three pins 114 (the same number as the number of planetary gears 120) arranged on its surface and supporting the planetary gears 120. The carrier 110 is rotatable with the planetary gears 120 supported by the pins 114.

The planetary gear 120 and the sun gear 130 have teeth 122 and 132 formed on their outer circumferential surfaces. The internal gear 140 has teeth 142 formed on its inner circumferential surface. The teeth 132 of the sun gear 130 mesh with the teeth 122 of the planetary gear 120, and the sun gear 130 rotates about the rotation center R shown in FIG. 2. The teeth 122 of the planetary gear 120 mesh with the teeth 132 of the sun gear 130 and the teeth 142 of the internal gear 140, and the planetary gear 120 rotates in conjunction with the rotation of the sun gear 130.

The plate 150 is attached to the opposite side of the carrier 110 and is a member that prevents the planetary gear 120 from falling off. The plate 150 has a hole 152 into which the pin 114 is inserted. The outer circumferential surface of the pin 114 has a circumferential groove 114a into which the C-ring 160 is fitted. As shown in FIG. 2(b), the planetary gear mechanism 100 is assembled by inserting the planetary gear 120 and the plate 150 onto the pin 114 and then fitting the C-ring 160 into the circumferential groove 114a.

As shown in Figures 1 and 2(a), in this embodiment, the carrier side markers 116 are provided on the end faces of two of the three pins 114. That is, in the planetary gear mechanism 100 of this embodiment, the carrier side markers 116 are provided at two of the vertices of a triangle (a triangle consisting of three pins 114) centered on the rotation center R of the sun gear.

Regarding the above "triangle," strictly speaking, when the three pins 114 are evenly spaced, they form an equilateral triangle. When they are unequally spaced, the three pins 114 form an isosceles triangle close to an equilateral triangle. However, whether the pins 114 are evenly or unequally spaced, the positions of the pins 114 are not extremely different, and the difference between the long and short sides of the spacing between the pins 114 on the carrier 110 is small. Therefore, whether they are evenly or unequally spaced, the carrier side marker 116 is positioned within the detection range of the sensor 102 (detector), which will be described later.

In this embodiment, a configuration in which the carrier side marker 116 is provided on two of the three pins 114 has been exemplified. However, this is not limited to this, and the carrier side marker 116 may be provided on the end surface of any pin 114 other than one of the multiple pins. For example, in a configuration having four pins 114, the carrier side marker 116 may be provided on the end surfaces of three of the pins 114.

In particular, in the planetary gear mechanism 100 of this embodiment, the carrier side marker 116 is a recess on the end face of the pin 114. This allows the carrier side marker 116 to be formed at the same time as the material of the carrier 110 is molded by die casting, so the carrier side marker 116 can be easily formed before cutting and grinding the carrier.

On the other hand, the plate 150 is provided with plate side markers 154 for identifying the phase of the plate 150 relative to the carrier 110. The plate side markers 154 are arranged at the two vertices of a triangle formed with the rotation center R of the sun gear 130 as its center.

The plate side marker 154 is hole-shaped. This allows the plate side marker 154 to be formed by the same press process as when the hole 152 is press-formed, making it easy to form.

Figure 3 is a diagram explaining the arrangement of the planetary gears 120 in the planetary gear mechanism 100. In the planetary gear mechanism 10 shown in Figure 3 (a), the planetary gears 120 are arranged at equal intervals relative to the sun gear 130. Therefore, the pins 114 supporting the planetary gears 120 are spaced at equal intervals.

On the other hand, as shown in FIG. 3(b), in the planetary gear mechanism 100 of this embodiment, the planetary gears 120 are arranged unequally, with each planetary gear 120 having a different angle relative to the sun gear 130. With this configuration, the spacing between adjacent pins 114 is different, and long sides and short sides are generated at such spacing. If an attempt is made to process such unequally spaced pins in the same way as equally spaced pins, the machined surface may shift from the center of the pin 114 when grinding and polishing the pin 114, or the cutter or grindstone may hit the end face of the pin 114, resulting in poor processing or deterioration of machinability.

Therefore, in the present invention, as described above, the carrier side marker 116 and the plate side marker 154 are placed at the two vertices of a triangle centered on the rotation center R of the sun gear. The processing device for the pin 114 is provided with two sensors 102 that detect the carrier side marker 116 at the two vertices of the triangle. In addition, the assembly device for the planetary gear mechanism 100 is provided with two sensors 104 that detect the plate side marker 154 at the two vertices of the triangle.

When the carrier side marker 116 and the plate side marker 154 are recesses, the sensors 102, 104 can be distance measuring sensors such as magnetic induction type. When paint is used for the carrier side marker 116 and the plate side marker 154, reflective optical sensors can be used for the sensors 102, 104. However, forming the markers with paint requires an additional process in a separate painting device, time is required for the paint to dry, and most importantly, the phase alignment of the carrier 110 and the plate 150 is required in the painting device, so it is preferable to form them as recesses as described above.

Figure 4 is a diagram explaining the detection of carrier side markers. As shown in Figure 4 (a), if the sensor 102 of the processing device does not detect any carrier side markers 116, i.e., if no carrier side markers 116 are formed on the pins 114, it can be determined that the planetary gears 120 in the planetary gear mechanism 100 are evenly spaced.

On the other hand, as shown in FIG. 4(b), if the sensor 102 detects two carrier side markers 116, it can be determined that "the arrangement of the planetary gears 120 is unequally spaced and the phase of the carrier 110 is correct."

In addition, if the planetary gears 120 in the planetary gear mechanism 100 are unequally spaced, and the sensor 102 detects only one of the two carrier side markers 116 as shown in Figures 4(c) and (d), it can be determined that the planetary gears 120 are unequally spaced in the carrier 110, and that the phase is incorrect in which direction of rotation. Therefore, the phase can be aligned by rotating the carrier 110.

Figure 5 is a diagram illustrating a comparative example in detecting the carrier side marker 116. Figures 5(a) and 5(b) show a case where there is one carrier side marker 116 and one sensor 102 of the processing device. As shown in Figure 5(a), if the sensor 102 is lucky enough to detect the carrier side marker 116, it can be determined that the carriers 110 are unevenly spaced and the phase is correct. However, as shown in Figure 5(b), when the sensor 102 does not detect the carrier side marker 116, it is impossible to determine whether the carriers 110 are evenly spaced or unevenly spaced, and even if they are unevenly spaced, it is impossible to determine which side the phase is shifted to. Therefore, when there is one carrier side marker 116 and one sensor 102, there is a possibility of erroneous detection and erroneous processing.

Figures 5(c) and (d) show the case where there is one carrier side marker 116 and two sensors 102. If the carrier side marker 116 is detected by either one of the two sensors 102 as shown in Figure 5(c), it can be determined that the carriers 110 are unequally spaced and the phase is correct. However, as shown in Figure 5(d), if the carrier side marker 116 is not detected by both of the two sensors 102, it is impossible to determine whether the spaces are equal or unequally spaced. Therefore, even when there is one carrier side marker 116 and two sensors 102, there is a possibility of erroneous detection and erroneous processing.

In response to these problems, according to the planetary gear mechanism 100 of this embodiment, carrier side markers 116 are formed on two of the pins 114 that support the three planetary gears 120. These are then detected by two sensors 102. This makes it possible to reliably determine whether the arrangement is even or unequal, and the phase shift of the carrier 110. Therefore, the carrier 110 can be positioned at the correct phase, making it possible to accurately machine the pins 114.

When assembling the planetary gear mechanism 100, the carrier 110 can be positioned in the correct phase by similarly detecting the carrier side marker 116 using a sensor (not shown) for the carrier side marker 116 of the assembly device, and the planetary gear 120 can be smoothly fitted into the pin 114.

Figure 6 is a diagram explaining the detection of the plate-side markers. As described above, the plate-side markers 154 are arranged at the two vertices of a triangle formed around the rotation center R of the sun gear 130. The sensor 104 of the assembly device performs sensing at the two vertices of the triangle.

As shown in FIG. 6(a), when two plate side markers 154 are detected by the sensor 104 of the assembly device, it can be determined that the plates 150 are unevenly spaced and that the phase of the plates 150 relative to the carrier 110 is correct. On the other hand, as shown in FIG. 6(b), when one plate side marker 154 is detected by the sensor 104 of the assembly device, it can be determined that the plates 150 are unevenly spaced and that the phase of the plates 150 relative to the carrier 110 is shifted. Note that when the plate side marker 154 is not detected by the sensor 104, it can be determined that the plates 150 are evenly spaced.

Therefore, with the above configuration, the plate 150 can be positioned at the correct phase, and the pin 114 can be smoothly inserted into the hole 152 of the plate 150. Overall, the planetary gear mechanism 100 can be assembled smoothly and reliably.

Although the preferred embodiment of the present invention has been described above with reference to the attached drawings, it goes without saying that the present invention is not limited to such an example. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

The present invention can be used as a planetary gear mechanism having a sun gear, multiple planetary gears, and an internal gear.

10... (equally spaced) planetary gear mechanism, 100... (unequally spaced) planetary gear mechanism, 102... sensor, 104... sensor, 110... carrier, 112... substrate, 114... pin, 114a... circumferential groove, 116... carrier side marker, 120... planetary gear, 122... teeth, 130... sun gear, 132... teeth, 140... internal gear, 142... teeth, 150... plate, 152... hole, 154... plate side marker, 160... C-ring, R... center of rotation

Claims (3)

A planetary gear mechanism having a sun gear, a plurality of planetary gears, and an internal gear,
The planetary gears are arranged unequally around the sun gear,
a carrier having a plurality of pins, the number of which is the same as the number of the planetary gears, for journaling the plurality of planetary gears;
a carrier side marker for identifying the phase of the carrier is provided on an end face of each of the pins other than one of the plurality of pins, and the carrier side marker is not provided on the end face of the one of the pins . The planetary gear mechanism according to claim 1, characterized in that the carrier side marker is a recess on the end face of the pin. a plate attached to the opposite side of the carrier to prevent the planetary gear from falling off;
a plate-side marker for identifying a phase of the plate relative to the carrier is provided on the plate;
3. The planetary gear mechanism according to claim 1, wherein the plate-side marker is disposed at a vertex of a polygon that is centered on an axis of the sun gear and corresponds to the carrier-side marker, among the vertices of the polygon that corresponds to the plurality of pins.

Images