JP7725340B2 - Power circulation type load test equipment - Google Patents

Description

The present invention relates to a power circulation type load testing device, and in particular to a testing device for testing planetary gears as load test targets.

Power circulation load testing equipment is known as a device for testing the strength and durability of power transmission components such as gears, rotating shafts, and belts. Among such power circulation load testing equipment, devices that use planetary gears in the power transmission path are known, such as those disclosed in Patent Documents 1 and 2. The power circulation load testing equipment disclosed in Patent Document 1 is a testing device for rotating shafts, connecting the rotating shaft to a sun gear and forming a power circulation mechanism via gears that can mesh with the planet carrier. Furthermore, an external gear is formed on the outer periphery of an internal gear that meshes with the planetary gear, and a gear that meshes with this external gear is placed. A torque loading device is engaged with this gear, creating a rotational difference between the sun gear and the power circulation mechanism via the internal gear and planetary gear, thereby applying torsion to the rotating shaft.

Furthermore, the power circulation load testing device disclosed in Patent Document 2 employs a planetary gear as a mechanism for adjusting the load torque in the power circulation path that constitutes the closed path. With a power circulation load testing device configured in this way, it is possible to apply torque to the closed path by using the rotational difference between the input rotating shaft and the output rotating shaft.

Japanese Unexamined Patent Publication No. 18739/1983 Japanese Patent Application Laid-Open No. 2012-7902

The power circulation load testing device disclosed in the above patent document is configured to adjust the torque applied to the device by using planetary gears as part of the device. However, no attempt has yet been made to apply the planetary gear mechanism itself to a power circulation load testing device, and power circulation load testing devices configured in this way have had problems such as difficulty adjusting torque during testing and an inability to form an oil film on the bearing metal (slide bearing) of the planetary gear, which can lead to damage.

The present invention therefore aims to provide a power circulation load testing device that can prevent damage to sliding bearings, even if the power circulation load testing device is constructed using only the planetary gear mechanism itself.

To achieve the above-mentioned objective, the power circulation load testing device of the present invention comprises a casing, a rotating shaft that penetrates the internal space of the casing and has an input port provided on the outside, a first sun gear and a second sun gear that are spaced apart along the longitudinal direction of the rotating shaft in the internal space of the casing, a planetary carrier that is rotatable around the rotating shaft and is provided with a gear support shaft, a first planetary gear that meshes with the first sun gear, a second planetary gear that is provided with a gear support shaft on the inner wall of the casing and meshes with the second sun gear, an internal gear that is rotatable around the rotating shaft in the internal space of the casing and has internal teeth that mesh with the first planetary gear and the second planetary gear, and a load generating device that is fixed to the casing and controls the rotational state of the planetary carrier.

Furthermore, in a power circulation load testing device having the above-mentioned characteristics, it is preferable that the planetary carrier is equipped with a load-applying gear, and the load generating device is equipped with a load adjustment gear that meshes with the load-applying gear. With such characteristics, rotating the load adjustment gear of the load generating device rotates the planetary carrier, thereby generating a load on the power circulation mechanism.

Furthermore, in a power circulation load testing device having the above-mentioned characteristics, the load generating device preferably includes an adjustment lever that rotates the load adjustment gear and an adjustment mechanism that positions the adjustment lever. This characteristic makes it possible to fine-tune the adjustment lever and maintain the load state via the adjustment mechanism.

A power circulation load testing device with the above-mentioned features can prevent damage to the sliding bearings, even if the power circulation load testing device is constructed using only the planetary gear mechanism itself.

1 is a cross-sectional view showing a schematic configuration of a power circulation load testing device according to an embodiment. FIG. 2 is a diagram illustrating a configuration of a load generating device. FIG. 10 is a cross-sectional view showing the state of an oil film formed between a rotating shaft of a planetary gear and a sliding bearing when the power circulation load testing device according to the embodiment is not in operation. FIG. 4 is a cross-sectional view showing the state of an oil film formed between a rotating shaft of a planetary gear and a sliding bearing when the power circulation load testing device according to the embodiment is operated.

Embodiments of the power circulation load testing device of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below are merely some of the preferred forms for implementing the present invention, and even if some of the configuration is changed, they can be considered part of the present invention as long as the effects are achieved.

[composition]
First, the configuration of a power circulation load testing apparatus according to this embodiment will be described with reference to FIGS. 1 and 2 . FIG. 1 is a cross-sectional view showing the schematic configuration of the power circulation load testing apparatus according to this embodiment, and FIG. 2 is a diagram illustrating the configuration of a load generating device. The power circulation load testing apparatus 10 according to this embodiment is basically composed of a casing 12, a rotating shaft 14, a pair of planetary gear mechanisms, and a load generating device 28. The casing 12 is a container having a cylindrical body 12a and a first cover 12b and a second cover 12c disposed at the end of the body 12a to form an internal space. The casing 12 supports the rotating shaft 14 (described in detail below) and accommodates the pair of planetary gear mechanisms in the internal space. While the casing 12 does not necessarily need to be sealed, it is desirable for it to be able to shield the internal space containing the rotating body from the external space in terms of dust and safety.

The rotating shaft 14 is a long rotating body that penetrates the internal space of the casing 12, with at least a portion of it located in the external space, and serves as the input section 14a. Bearings 16a and 16b are provided at the intersection of the casing 12 and the rotating shaft 14 (between the first cover 12b and the second cover 12c in the embodiment shown in Figure 1), allowing the rotating shaft 14 to rotate independently within the internal space of the casing.

The pair of planetary gear mechanisms includes a first planetary gear mechanism consisting of a first sun gear 18a, a first planetary gear 18b, a planet carrier 18c, and an internal gear 22, and a second planetary gear mechanism consisting of a second sun gear 20a, a second planetary gear 20b, and an internal gear 22. The first sun gear 18a is a gear arranged on the rotary shaft 14 (on the input section 14a side in the embodiment shown in FIG. 1), and multiple first planetary gears 18b are gears arranged on the outer periphery of the first sun gear 18a so as to mesh with the first sun gear 18a. In this embodiment, the gear support shafts 24 of the multiple first planetary gears 18b are positioned via the planet carrier 18c, described in detail below, so that the gear support shafts 24 of each of the multiple first planetary gears 18b are arranged on the circumference of a single circle concentric with the first sun gear 18b.

The planetary carrier 18c is an element for positioning the gear support shaft 24 of the first planetary gear 18b. In this embodiment, it is positioned between the internal gear 22 and the first cover 12b, with a bearing 16c provided between it and a boss provided on the first cover 12b, and is positioned so that it can impart individual rotation to the rotating shaft 14 and casing 12. Furthermore, in this embodiment, the planetary carrier 18c has a stepped portion on the side facing the first cover 12b, and a load-applying gear 18c1 is provided on the outer periphery of this stepped portion.

The second sun gear 20a is a gear positioned at a distance from the first sun gear 18a relative to the rotation axis 14, and multiple second planetary gears 20b are gears positioned on the outer periphery of the second sun gear 20a so as to mesh with the second sun gear 20a. In this embodiment, the gear support shafts 26 of each of the multiple second planetary gears 20b are arranged on the second cover 12c so that they are positioned on the circumference of a single circle that is concentric with the second sun gear 20a.

The internal gear 22 meshes with each of the multiple first planetary gears 18b and the multiple second planetary gears 20b, and is an element that transmits the power generated between them. In this embodiment, the internal gear 22 has first internal teeth 22a that mesh with the first planetary gear 18b and second internal teeth 22b that mesh with the second planetary gear 20b.

Here, a plain bearing 40 is provided between the first planetary gear 18b and the gear support shaft 24, and between the second planetary gear 20b and the gear support shaft 26.

The load generator 28 is an element that generates a load on the power circulation mechanism formed by the rotating shaft 14, first sun gear 18a, first planetary gear 18b, internal gear 22, second planetary gear 20b, and second sun gear 20a. In this embodiment, by restricting the free rotation of the planetary carrier 18c starting from the casing 12 and imparting a predetermined rotation to the planetary carrier 18c, a torque that generates a load is applied to the power transmission mechanism between the rotating shaft 14 and the internal gear 22, i.e., between the first sun gear 18a and the first planetary gear 18b, the first planetary gear 18b and the first internal gear 22a, the second sun gear 20a and the second planetary gear 20b, and the second planetary gear 20b and the second internal gear 22b.

Specifically, the load generator 28 is configured to include a load adjustment gear 30, an adjustment lever 32, and an adjustment mechanism 34. The load adjustment gear 30 is an element that restricts the free rotation of the planetary carrier 18c and also provides the desired rotation. In this embodiment, it is positioned to mesh with a load-applying gear 18c1 provided on the outer periphery of the planetary carrier 18c.

The adjustment lever 32 supports the load adjustment gear 30 and is exposed to the outside of the casing 12. It is an element that rotates the load adjustment gear 30 when the lever swings. Furthermore, because the rotation shaft 32a of the adjustment lever 32 (the shaft that supports the load adjustment gear 30) is positioned on the first cover 12b, the free rotation of the planetary carrier 18c, which has the load-applying gear 18c1 that meshes with the load adjustment gear 30, is restricted.

The adjustment mechanism 34 is an element used to position the adjustment lever 32 and determine the amount of load applied. The swinging portion of the adjustment lever 32 is positioned between the two wall surfaces 36a of the U-shaped bracket 36, and a bolt 38 is threaded from the two wall surfaces 36a toward the swinging portion of the adjustment lever 32. With this type of adjustment mechanism 34, it is possible to control the swing amount of the adjustment lever 32 and position it by tightening or loosening the bolt 38 threaded into the wall surface 36a.

In the power circulation load testing device 10 according to this embodiment, a first physical quantity detection means such as an acceleration sensor (not shown) is provided on any of the first sun gear 18a, second sun gear 20a, first planetary gear 18b, second planetary gear 20b, internal gear 22, sliding bearing 40, and gear support shafts 24 and 26, enabling detection of changes in vibration acceleration. This configuration makes it possible to detect the value at which the vibration acceleration peaks (natural frequency).

In addition, the power circulation load control device 10 is configured to provide a second physical quantity detection means, such as a strain gauge, at the tooth root of any of the first sun gear 18a, second sun gear 20a, first planetary gear 18b, second planetary gear 20b, and internal gear 22. This allows the stress generated at the tooth root to be calculated when the rotation speed or circulation power is changed, thereby enabling dynamic load confirmation. This configuration makes it possible to compare the actual measured values (calculated values based on the detected physical quantities) and calculated values (theoretical values based on design conditions) of the dynamic load and natural frequency acting on each gear (the gear being measured) during operation. Therefore, if a discrepancy occurs between the actual measured value and the calculated value, a calculation method for determining the gear dynamic load can be constructed by adding a correction formula to account for the cause of the discrepancy.

[Effect]
In the power circulation load test apparatus 10 configured as described above, tests are performed using the second sun gear 20a, the second planetary gear 20b, and the second internal gear 22 as test specimens. In the power circulation load test apparatus 10, first, rotation is applied to the input portion of the rotating shaft 14 in an unloaded state to rotate the rotating shaft. As a result, power is transmitted to the first planetary gear 18b and the second planetary gear 20b via the first sun gear 18a and the second sun gear 20a attached to the rotating shaft 14, and then to the internal gear 22, thereby completing power circulation.

After continuing operation under no load for a predetermined period of time, the adjustment lever 32 is rotated via the adjustment mechanism 34 of the load generator 28, which rotates the planetary carrier 18c via the load-applying gear 18c1 that meshes with the load adjustment gear 30, thereby generating a load on the power circulation mechanism of the power circulation load testing device 10.

The load applied via the load generator 28 can be increased or decreased depending on the operating state (rotation state) of the power circulation load testing device 10 so that the desired load is applied to the test specimen.

[effect]
In a power circulation type loading device not equipped with the load generating device 28 described above, in order to apply a load to a test sample, it is necessary to apply a load to two sets of planetary gears (elements corresponding to the first planetary gear 18b and the second planetary gear 20b in this embodiment) in advance during the assembly stage. In this assembled state, a load acts between the gear support shaft and the plain bearing even when the gears are stationary. However, when the gears are stationary, as shown in FIG. 3 (in which the components in this embodiment are labeled), an oil film may not be formed between the gear support shaft 24 of the first planetary gear 18b and the plain bearing 40, or between the gear support shaft 26 of the second planetary gear 20b and the plain bearing 40. Rotating the planetary gears (the first planetary gear 18b and the second planetary gear 20b in this embodiment) without an oil film between them may result in damage (galling) to the plain bearing (the plain bearing 40 in FIG. 3).

On the other hand, when the load generating device 28 is attached to the power circulation load testing device 10 as in the above embodiment, it becomes possible to apply a load to the test sample after operating it in an unloaded state. Therefore, after operating the power circulation load testing device 10 in an unloaded state and forming a wedge oil film as shown in Figure 4, which ensures good lubrication between the gear support shafts 24, 26 and the plain bearing 40, a load can be applied to the power circulation mechanism. Therefore, even if a load is applied to the power circulation mechanism, there is no risk of damage occurring between the gear support shafts 24, 26 and the plain bearing 40.

In the above embodiment, in order to simplify the mechanism, the load generating device 28 is configured to be operated manually. However, the configuration and control of the load generating device 28 are not limited to this. In other words, any configuration is acceptable as long as it can rotate the planetary carrier 18c at any timing and maintain that rotated state. Furthermore, the power source for its operation can be electric, hydraulic, or other.

10...Power circulation type load test apparatus, 12...Casing, 12a...Body portion, 12b...First cover, 12c...Second cover, 14...Rotating shaft, 14a...Input portion, 16a, 16b, 16c...Bearings, 18a...First sun gear, 18b...First planetary gear, 18c...Planet carrier, 18c1...Load-applying gear, 20a...Second sun gear, 20b...Second planetary gear, 22...Internal gear, 22a...First internal teeth, 22b...Second internal teeth, 24...Gear support shaft, 26...Gear support shaft, 28...Load generating device, 30...Load adjusting gear, 32...Adjusting lever, 32a...Rotating shaft, 34...Adjusting mechanism, 36...Bracket, 36a...Wall surface, 38...Bolt, 40...Plain bearing.

Claims (3)

A casing;
a rotating shaft that passes through the internal space of the casing and has an input portion provided on the outside;
a first sun gear and a second sun gear arranged in an internal space of the casing and spaced apart from each other along the longitudinal direction of the rotation shaft;
a planetary carrier rotatable around the rotation axis and provided with a gear support shaft; and a first planetary gear meshing with the first sun gear;
a second planetary gear having a gear support shaft provided on an inner wall of the casing and meshing with the second sun gear;
an internal gear that has internal teeth that mesh with the first planetary gear and the second planetary gear and is arranged rotatably around the rotation shaft in the internal space of the casing;
a load generating device fixed to the casing and controlling the rotation state of the planetary carrier. the planet carrier includes a load-applying gear;
2. The power circulation type load testing apparatus according to claim 1, wherein the load generating device includes a load adjusting gear that meshes with the load applying gear. The load generating device includes an adjustment lever that rotates the load adjustment gear;
3. A power circulation type load testing device according to claim 2, further comprising an adjustment mechanism for positioning said adjustment lever.