JP2013036809A - Power transmission shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission shaft in which remarkable attenuation effects can be obtained.SOLUTION: A power transmission shaft 50 comprises a shaft body 52 which transmits power, and a multiple cylinder member 54 which is disposed so as to match its centerline with the shaft body 52. The multiple cylinder member 54 includes a first cylinder member 56 of which only the one-side terminal portion is integrally mounted to a one-side terminal portion of the shaft body 52, and a second cylinder member 58 of which only the one-side terminal portion is integrally mounted to another-side terminal portion of the shaft body 52. Between the first cylinder member 56 and the second cylinder member 58, sealing spaces Y1-Y3 for viscous materials are formed cylindrically.

Description

  The present invention relates to a power transmission shaft, and more particularly, to a power transmission shaft that transmits power between an engine and a dynamometer in an engine test apparatus.

  An engine bench is known as an engine test apparatus. The engine bench is a device that evaluates whether a test engine has a predetermined performance. The test engine is mounted on a table, and its output shaft is connected to a dynamometer via a shaft. The engine performance is measured and evaluated by measuring the torque and the rotational speed while absorbing the rotational force of the engine output shaft with the dynamometer.

  By the way, in an engine bench, there exists a possibility that resonance may generate | occur | produce in a specific frequency (rotation speed) in a shaft. The resonance gain increases with the natural frequency as a vertex, and a resonance phenomenon occurs at the peripheral frequency. Therefore, conventionally, it is designed to operate in a region where resonance is avoided by adjusting the rigidity of the shaft and the inertia value of the inertia connected to the shaft. Further, as another countermeasure, Patent Document 1 shifts the resonance region by detachably attaching a flywheel to the shaft or using couplings having different rigidity. In Patent Document 2, the resonance point is set to an idling frequency or lower.

  However, since Patent Document 1 and Patent Document 2 merely shift the resonance point from the operation region, there is a risk that the operation region may be restricted or the device being operated may be damaged if the resonance point is not shifted well. It was.

  Therefore, the applicant of the present application has proposed a shaft for suppressing resonance itself in Patent Document 3. This will be described with reference to a basic torsional resonance system shown in FIG. In the system shown in the figure, two rotating disks 1 and 2 are provided on both sides of the shaft 3. The shaft 3 has a torsional rigidity k and a damping coefficient c, the rotating disk 1 has an inertia J1 and a displacement angle θ1, and the rotating disk 2 has an inertia J2 and a displacement angle θ2. The equation of motion of this system is shown as follows.

この式の第２項から分かるように、角速度差が生じる部位に減衰機構を設置することで共振ゲインを抑えることができ、且つ、その角速度差が大きいほど減衰効果が大きくなる。そこで、特許文献３では、ネジリ共振時に角速度差が生じる部位に粘性体の封入空間を形成し、減衰を行っている。具体的には、図９に概念図を示すように、シャフト本体４の外側に円筒部材５を配置し、その片側の端部５ａのみをシャフト本体４の一方の端部に取り付けるとともに、シャフト本体４と円筒部材５との間に粘性体６を封入している。その結果、円筒部材５の他方側の端部５ｂとシャフト本体４との間には角速度差が生じ、その角速度差に伴って減衰効果が得られ、共振ゲインを抑制することができる。実際、特許文献３に示すシャフトを用いれば、共振ゲインを抑制する効果が得られることが試験結果から分かっている。そして、現状では、より大きな減衰効果が得られるシャフトが望まれている。

As can be seen from the second term of this equation, the resonance gain can be suppressed by installing a damping mechanism at a site where the angular velocity difference occurs, and the damping effect increases as the angular velocity difference increases. Therefore, in Patent Literature 3, a viscous enclosure space is formed at a site where an angular velocity difference occurs during torsional resonance, and attenuation is performed. Specifically, as shown in a conceptual diagram in FIG. 9, a cylindrical member 5 is disposed outside the shaft body 4, and only one end portion 5 a is attached to one end portion of the shaft body 4. A viscous body 6 is enclosed between 4 and the cylindrical member 5. As a result, an angular velocity difference is generated between the other end portion 5b of the cylindrical member 5 and the shaft body 4, and a damping effect is obtained along with the angular velocity difference, so that the resonance gain can be suppressed. In fact, it is known from the test results that the effect of suppressing the resonance gain can be obtained by using the shaft shown in Patent Document 3. At present, a shaft that can provide a greater damping effect is desired.

JP-A-9-78616 Patent 3918435 Japanese Patent Application 2010-19860

  The present invention has been made in view of such circumstances, and an object thereof is to provide a power transmission shaft capable of obtaining a greater damping effect.

  In order to achieve the above object, the invention according to claim 1 includes a shaft main body for transmitting power, and a plurality of cylindrical members arranged so as to coincide with a center line of the shaft main body. The cylindrical member includes a first cylindrical member in which only one end is fixed to one end of the shaft main body, and a second one in which only one end is fixed to the other end of the shaft. A shaft for power transmission is provided in which an enclosed space of a viscous body is formed in a cylindrical shape between the first cylindrical member and the second cylindrical member.

  According to the present invention, the enclosure space for the viscous material is formed between the first cylindrical member and the second cylindrical member. Since the first cylindrical member has only one end thereof attached to one end of the shaft body, the rotation speed thereof is substantially the same as that of the one end of the shaft body. . On the other hand, since the second cylindrical member is attached to the other end of the shaft body only on one end thereof, the rotational speed thereof is substantially the same as the other end of the shaft body. Become. Therefore, the cylindrical enclosing space sandwiched between the first cylindrical member and the second cylindrical member has a constant speed difference in the entire axial direction (that is, the speed of the first cylindrical member and the second cylindrical member Difference from speed). Therefore, in the enclosed space, a large rotational speed difference is generated over the whole at the time of torsional resonance, and a large damping effect is obtained.

  According to a second aspect of the present invention, in the first aspect, a plurality of the first cylindrical members and the second cylindrical members are alternately provided, and enclosure spaces for the viscous material are formed in multiple. . According to the present invention, the viscous space is formed in multiple layers, so that the damping effect by the viscous body can be further increased.

  According to a third aspect of the present invention, in the first or second aspect, the viscosity between the first or second cylindrical member disposed to face the surface of the shaft main body and the surface of the shaft main body is between. The body is enclosed. According to the present invention, since the viscous material is also sealed between the shaft main body, a damping effect can be obtained also in this portion.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the power transmission shaft is a shaft connecting an output shaft of an engine and a rotating shaft of a dynamometer. The present invention is particularly effective as a shaft of an engine test apparatus that easily generates torsional vibration.

  According to the present invention, the enclosure space for the viscous material is formed between the first cylindrical member attached to the one end portion of the shaft body and the second cylindrical member attached to the other end portion of the shaft body. As a result, a substantially uniform rotational speed difference is generated throughout the enclosed space, and a large damping effect can be obtained by the viscous material.

Schematic configuration diagram of an engine bench to which the present invention is applied The fragmentary perspective view which shows the shaft for power transmission of 1st Embodiment. Sectional drawing which shows the shaft for power transmission of 1st Embodiment. Sectional drawing which shows the shaft for power transmission of 2nd Embodiment. Sectional drawing which shows the shaft for power transmission of 3rd Embodiment. Sectional drawing which shows the shaft for power transmission of 4th Embodiment. Sectional drawing which shows the shaft for power transmission of 5th Embodiment. Diagram showing basic torsional resonance system Conceptual diagram explaining another proposed power transmission shaft

  Hereinafter, preferred embodiments of a power transmission shaft according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an engine test apparatus 10 to which a power transmission shaft (hereinafter simply referred to as a shaft) 50 according to the present embodiment is applied.

  The engine test apparatus 10 shown in FIG. 1 is an apparatus for measuring and evaluating the performance of the engine 12 to be tested. The engine test apparatus 10 mainly includes an engine 12, a dynamometer 14, a dynamo control unit 16, an engine control unit 18, a control device 20, and The shaft member 32 includes the shaft 50.

  The engine 12 is fixed to a gantry 22 and a combustion chamber (not shown) is provided in the engine 12. An air intake pipe 24 for air suction is connected to the combustion chamber, and an intake flow adjusting throttle 26 is provided in the intake pipe 24. An exhaust pipe 28 is connected to the combustion chamber, and an exhaust gas purification catalyst mounting portion 30 is provided in the exhaust pipe 28.

  The output shaft of the engine 12 is connected to the dynamometer 14 via the shaft member 32. The shaft member 32 is configured by connecting a plurality of shaft members including the shaft 50 (see FIG. 2) of the present invention. A torque meter 36 is attached to the shaft member 32, and the torque is measured by the torque meter 36. In the present embodiment, the torque is measured by the torque meter 36. However, the present invention is not limited to this. For example, the torque may be detected from the output value of the dynamometer 14. In addition to the torque meter 36, a clutch, a transmission, various connecting means, and the like may be inserted depending on the purpose. Further, means for measuring the state of the engine 12 other than the torque (for example, the temperature of the exhaust gas) may be inserted.

  The dynamometer 14 is a device that applies a predetermined load torque to the engine 12, and can set the load torque by varying the current and voltage. As the dynamometer 14, it is preferable to use a low inertia dynamometer. By using the low inertia dynamometer, a stable output corresponding to a rapid change in the rotational speed from low speed rotation to high speed rotation can be obtained.

  A dynamometer control unit 16 is connected to the dynamometer 14. The dynamo control unit 16 is means for variably controlling the current / voltage applied to the dynamometer 14, and the load of the engine 12 connected to the dynamometer 14 is controlled by variably controlling the current / voltage with the dynamo control unit 16. Torque is controlled.

  On the other hand, the engine 12 is connected to the engine control unit 18. The engine control unit 18 is a means for driving and controlling the engine 12 by giving a control command value such as a throttle opening degree and an ignition advance angle to the engine 12, and is usually an ECU or an engine control in which a bypass circuit is added to the ECU. Realized with a circuit. Instead of the ECU, a DSP (Digital Signal Processor) called a virtual ECU may be used. A control parameter (for example, a predetermined throttle opening) is given to the engine 12 by the engine control unit 18. As a result, the engine 12 rotates, and the rotation is transmitted to the dynamometer 14 via the shaft 50. The control parameters given from the engine control unit 18 include the rotational speed, throttle opening, fuel injection amount, air injection amount, fuel / air mixture ratio, ignition time (in the case of a gasoline engine), fuel injection control. There are various parameters such as the method (in the case of a diesel engine).

  The dynamometer 14, dynamo control unit 16, engine control unit 18, and torque meter 36 described above are connected to the control device 20. Data such as torque and rotational speed is input from the torque meter 36 to the control device 20, and control data such as throttle opening is input from the engine control unit 18. The input data is temporarily stored in the memory, and then output to the arithmetic processing circuit as necessary to calculate torque and the like. At that time, data signal processing such as noise removal may be performed by various signal processing circuits.

The control device 20 may create an engine model from the obtained data, or may execute a simulation using the model. In the control device 20, various condition settings such as control parameters such as throttle opening, fuel injection timing, ignition advance, injection time, VVT, EGR, intake air temperature, exhaust temperature, fuel injection amount, air injection amount, etc. Measurement parameters such as NO _X density, HC density, CO concentration, CO ₂ concentration, fuel consumption, and water temperature may be set.

  Next, the shaft 50 which is a characteristic part of the present invention will be described. FIG. 2 is a partial perspective view showing the internal configuration of the shaft 50 of the first embodiment, and shows a state in which a part is cut away. FIG. 3 is a cross-sectional view of the shaft 50.

  As shown in these drawings, the shaft 50 is mainly composed of a shaft main body 52, a connecting member 53, and a multiple cylindrical member 54.

  The shaft main body 52 is a member that transmits power (rotational force) from the input side (motor or the like) to the output side (dynamometer or the like), and is formed in a columnar shape by a metal such as titanium 6Al-4V alloy or stainless steel, for example. . Here, the left side of FIG. 3 is the input side, and the right side is the output side. The material of the shaft main body 52 is not limited to the above, and other materials such as carbon may be used.

  Both ends of the shaft main body 52 are attached to a connecting member 53 via a coupling member (not shown), and the connecting member 53 is further connected to another shaft member (not shown). The configuration of the coupling member is not particularly limited. For example, a leaf spring coupling (flexible joint) is used. Although the structure of the leaf spring coupling is not illustrated, a pair of joint bodies formed in a disk shape are connected by bolts or the like, and a metal leaf spring formed in a ring shape is interposed between the joint bodies. It is provided and this leaf spring is fixed to the joint body. By using such a leaf spring coupling, the displacement of the shaft center can be adjusted by the leaf spring, and only the shaft torque can be transmitted without transmitting the bending moment, which corresponds to large torque and high speed rotation. be able to. Further, since the leaf spring coupling configured as described above can be easily attached and detached, a multiple cylindrical member 54 described later can be easily attached to the shaft body 52.

  The multi-cylindrical member 54 has a multi-cylindrical structure in which a plurality of cylindrical members having different diameters are concentrically arranged, and the multi-cylindrical member 54 is fixed in a state where the shaft main body 52 is inserted. The multi-cylindrical member 54 of the present embodiment has a quadruple cylindrical structure, an input side cylindrical member 56 (corresponding to a first cylindrical member) 56 having a double cylindrical structure, and an output side having a double cylindrical structure. And a cylindrical member 58 (corresponding to a second cylindrical member).

  As shown in FIG. 3, the input side cylindrical member 56 includes two cylindrical portions 56A and 56B having different diameters. The cylindrical portion 56A has a diameter slightly larger than the outer diameter of the shaft main body 52, and is fixed in a state where the shaft main body 52 is inserted. The cylindrical portion 56A is disposed concentrically with the shaft main body 52, and a cylindrical enclosed space X is formed between the outer peripheral surface of the shaft main body 52 and the cylindrical portion 56A. The enclosed space X is formed so as to have a constant gap in the axial direction and in the circumferential direction.

  The cylindrical portion 56B of the input side cylindrical member 56 is arranged so that the center line coincides with the cylindrical portion 56A. The cylindrical portion 56B has a diameter larger than the cylindrical portion 58A of the output side cylindrical member 58 and smaller than the cylindrical portion 58B, and is inserted between the cylindrical portion 58A and the cylindrical portion 58B in the attached state. Is done.

  As for the above-mentioned cylinder part 56A and cylinder part 56B, only the input side end (the left side in FIG. 3) is integrally attached to the input side end of the shaft body 52, and the opposite end is fixed. It is in a free state without being. Although FIG. 3 shows an example in which the cylindrical portion 56A and the cylindrical portion 56B are an integrated product, the present invention is not limited to this and may be configured by separate members. In that case, the cylindrical portion 56 </ b> A and the cylindrical portion 56 </ b> B may be integrally attached at the input side end of the shaft body 52.

  Similar to the input side cylindrical member 56, the output side cylindrical member 58 includes two cylindrical portions 58A and 58B having different diameters. The diameter of the cylindrical portion 58 </ b> A is slightly larger than the cylindrical portion 56 </ b> A of the input side cylindrical member 56 and slightly smaller than the cylindrical portion 56 </ b> B of the input side cylindrical member 56. In the attached state, the cylindrical portion 58A is inserted between the cylindrical portions 56A and 56B, and is arranged concentrically with the cylindrical portions 56A and 56B. Thereby, a cylindrical enclosure space Y1 is formed between the cylinder part 56A and the cylinder part 58A, and a cylindrical enclosure space Y2 is formed between the cylinder part 56B and the cylinder part 58A. The enclosure space Y1 and the enclosure space Y2 are formed so as to have a constant gap in the axial direction and in the circumferential direction.

  The cylinder part 58B of the output side cylindrical member 58 is arranged so that the center line coincides with the cylinder part 58A. Further, the cylindrical portion 58B is formed so that its diameter is slightly larger than the cylindrical portion 56B of the input side cylindrical member 56, and is disposed outside the cylindrical portion 56B in the mounted state and concentrically with the cylindrical portion 56B. Is done. Thereby, a cylindrical enclosing space Y3 is formed between the cylinder part 56B and the cylinder part 58B. The enclosure space Y3 is formed so as to have a constant gap in the axial direction and in the circumferential direction.

  The cylinder part 58 </ b> B is formed longer than the cylinder part 58 </ b> A, and the tip thereof extends to the input side from the input side cylindrical member 56. A disc-shaped sealing member 58D is provided at the tip of the cylindrical portion 58B. A hole through which the shaft main body 52 is inserted is formed at the center of the sealing member 58 </ b> D, and is disposed with a slight gap with respect to the shaft main body 52. By providing the sealing member 58D, it is possible to prevent the viscous body from leaking from the enclosed space X and the enclosed spaces Y1 to Y3 due to centrifugal force when the shaft 50 rotates.

  Only the end portion on the output side (right side in FIG. 3) of the cylindrical portion 58A and the cylindrical portion 58B is integrally attached to the output side connecting member 53 of the shaft body 52, and the opposite end portions are fixed. It is in a free state. In FIG. 3, the cylindrical portion 58A and the cylindrical portion 58B are shown as an integrated product, but the present invention is not limited to this, and may be configured by separate members. In that case, the cylindrical portion 58A and the cylindrical portion 58B may be integrally attached at the output-side end portion of the shaft main body 52. Further, in the present embodiment, the cylinder portion 58A and the cylinder portion 58B are fixed to the output side connecting member 53, but may be directly fixed to the output side end portion of the shaft body 52.

  As described above, the multi-cylindrical member 54 includes the input-side cylindrical member 56 and the output-side cylindrical member 58. Between the input-side cylindrical member 56 and the output-side cylindrical member 58, cylindrical enclosure spaces Y1, Y2, Y3 is formed. A cylindrical enclosing space X is formed between the input side cylindrical member 56 and the shaft body 52.

  The size of the gap (interval between the inner peripheral surface and the outer peripheral surface) in these enclosing spaces Y1 to Y3 and the enclosing space X is not particularly limited, and various modes are possible. However, it is preferable to set so that the gap becomes smaller as the inner enclosed space is reached. Thereby, the later-described attenuation effect can be further increased.

  The enclosure spaces Y1 to Y3 and the enclosure space X described above are in communication with each other, and the same viscous material is enclosed therein. The type of the viscous material is not particularly limited as long as it has a viscosity that can absorb vibrations (specifically, a viscosity determined by the size of the gap). Used. When the shaft 50 is assembled, the grease can be filled in the enclosing spaces Y1 to Y3 by applying the grease that has been attached to the enclosing spaces Y1 to Y3 and the enclosing space X and is applied after the assembly. .

  Next, the operation of the shaft 50 configured as described above will be described.

  As described above, the multi-cylindrical member 54 is attached to the shaft main body 52, and the cylindrical enclosing space X and the enclosing spaces Y <b> 1 to Y <b> 3 are formed around the shaft main body 52. In these enclosure space X and enclosure spaces Y1 to Y3, a viscous material is enclosed, and if a difference occurs between the rotation speed on the inner peripheral surface side and the rotation speed on the outer peripheral surface side, the generated rotation speed difference is generated. Attenuating effect is obtained according to the size of.

  Here, a state where torsional resonance occurs in the shaft 50 will be described. In a state where torsional resonance occurs, the shaft body 52 is twisted, and the rotational speed is different between the input side and the output side of the shaft body 52. Hereinafter, the rotational speed difference generated in the enclosed space X and the enclosed spaces Y1 to Y3 will be described with the rotational speed on the input side of the shaft body 52 being ω1 and the rotational speed on the output side being ω2.

  The shaft body 52 gradually changes in rotational speed from ω1 to ω2 from the input side to the output side in the axial direction. On the other hand, the input-side cylindrical member 56 of the multi-cylindrical member 54 has an input-side end fixed to the input-side end of the shaft body 52, and the output-side end is free (that is, fixed). Is not). Therefore, the entire input side cylindrical member 56 (that is, the cylindrical portion 56A and the cylindrical portion 56B) rotates at a substantially uniform rotational speed ω1. On the other hand, the output-side cylindrical member 58 has an output-side end fixed to the output-side end of the shaft body 52, and the input-side end is free. Accordingly, the entire output-side cylindrical member 58 (that is, the cylindrical portion 58A and the cylindrical portion 58B) rotates at a substantially uniform rotational speed ω2.

  By the way, the enclosed space X is sandwiched between the outer peripheral surface of the shaft main body 52 and the cylindrical portion 56 </ b> A of the input side cylindrical member 56. As described above, the cylindrical portion 56A has a substantially uniform rotational speed ω1, while the shaft main body 52 changes from ω1 to ω2. For this reason, the rotational speed difference generated between the inner peripheral surface and the outer peripheral surface in the enclosed space X is large at the output side end portion as | ω1−ω2 |, whereas both at the input side end portion are ω1. Therefore, it is almost zero. Therefore, the attenuation effect due to the viscous material obtained in the enclosed space X is reduced at the end portion on the input side, and the attenuation effect as a whole is substantially halved.

  On the other hand, the enclosure spaces Y1 to Y3 are sandwiched between the input side cylindrical member 56 and the output side cylindrical member 58, respectively. As described above, the input-side cylindrical member 56 has a substantially uniform rotational speed ω1, and the output-side cylindrical member 58 has a substantially uniform rotational speed ω2. For this reason, in the enclosed spaces Y1 to Y3, the rotational speed difference between the inner peripheral surface and the outer peripheral surface is always | ω1−ω2 | in the axial direction. Therefore, in the enclosing spaces Y1 to Y3, a large rotational speed difference occurs in any part in the axial direction, and a large damping effect is obtained as a whole.

  Thus, in the present embodiment, only the input side end of the input side cylindrical member 56 is fixed to the input side end of the shaft main body 52, and only the output side end of the output side cylindrical member 58 is output from the shaft main body 52. Since it is fixed to the side end, in the enclosed spaces Y1 to Y3 formed between them, a uniform rotational angle difference | ω1−ω2 | is generated in the axial direction, and a large damping effect is obtained as a whole. In particular, in the present embodiment, the enclosure spaces Y1 to Y3 are formed in triplicate by forming the multiple cylindrical member 54 in quadruplicate, so that a three-fold attenuation effect can be obtained.

  Further, in the present embodiment, the enclosed space X is formed in addition to the enclosed spaces Y1 to Y3. That is, the gap between the shaft body 52 and the multiple cylindrical member 54 is used as the enclosed space X. Therefore, this embodiment can obtain a greater attenuation effect. In the present embodiment, the viscous material is also enclosed in the gap (encapsulation space X) between the shaft main body 52 and the multiple cylindrical member 54, but the present invention is not limited to this, and only the enclosure spaces Y1 to Y3. You may make it fill with a viscous body. This also applies to the following embodiments.

  In the above-described embodiment, the multi-cylindrical member 54 is configured in quadruple and the enclosure spaces Y1 to Y3 are formed in triple. However, the present invention is not limited to this, and a multi-layer configuration may be used. For example, the shaft 60 according to the second embodiment shown in FIG. More specifically, the input side cylindrical member 56 is formed with a cylindrical portion 56C on the outer side of the cylindrical portion 56A and the cylindrical portion 56B, and this cylindrical portion 56C is connected to the input side of the shaft main body 52 together with the cylindrical portions 56A and 56B. It is fixed to the end of the. The cylindrical portion 56C is formed larger than the cylindrical portion 58B of the output side cylindrical member 58, and a cylindrical enclosed space Y4 is formed between the cylindrical portion 56C and the cylindrical portion 58B. On the other hand, the output side cylindrical member 58 is formed with a cylindrical part 58C on the outer side of the cylindrical part 58A and the cylindrical part 58B. The cylindrical part 56C is formed at the output side end of the shaft main body 52 together with the cylindrical parts 58A and 58B. It is fixed. Moreover, the cylinder part 58C is formed larger than the cylinder part 56B of the input side cylindrical member 56, and a cylindrical enclosed space Y5 is formed between the cylinder part 58C and the cylinder part 56B. These enclosure spaces Y4 and Y5 are also filled with a viscous material, and a damping effect is obtained according to the rotational speed difference | ω1-ω2 | between the inner and outer peripheral surfaces. According to the shaft 60 configured in this way, since the enclosed spaces Y1 to Y5 are formed in five layers, a larger damping effect can be obtained.

  In the above-described embodiment, a plurality of cylindrical enclosure spaces Y1 to Y5 in which the difference in rotational speed between the inner peripheral surface and the outer peripheral surface is substantially uniform are provided, but only one may be provided. For example, in the shaft 70 according to the third embodiment shown in FIG. 5, the multiple cylindrical member 74 is configured to be double. The input side cylindrical member 56 of the multiple cylindrical member 74 includes only the cylindrical portion 56A, and the output side cylindrical member 58 includes only the cylindrical portion 58A. Therefore, only one sealed space Y1 is formed between the cylindrical portion 56A and the cylindrical portion 58A. In this case as well, the rotational speed difference becomes substantially uniform, so that a large damping effect can be obtained. Although omitted in FIG. 5, it is preferable to provide a leakage prevention means for preventing the viscous material from leaking from the enclosed space Y1 at the tip of the outermost cylindrical portion 58A. As the leakage preventing means, for example, a method of providing a disk-shaped sealing member 58D or providing a labyrinth structure as in the above-described embodiment can be considered.

  Moreover, although embodiment mentioned above is an example in which the input side cylindrical member 56 and the output side cylindrical member 58 have the same number of cylinder parts, it is not limited to this, The input side cylindrical member 56 and the output side cylindrical member The number of the 58 cylinder portions may be different. For example, in the shaft 80 of the fourth embodiment shown in FIG. 6, the multiple cylindrical member 84 is formed in three layers, the input side cylindrical member 56 includes two cylindrical portions 56A and 56B, and the output side cylindrical member 58. Has only one cylindrical portion 58A. Also in this case, since the enclosed spaces Y1 and Y2 in which the rotational speed difference is substantially uniform are formed, a large attenuation effect can be obtained. In the case of FIG. 6 as well, as in the case of FIG. 5, it is preferable to provide the leakage preventing means at the end of the cylindrical portion 56B.

  In the above-described embodiment, the enclosure spaces Y1 to Y5 are formed outside the shaft main body 52, but the present invention is not limited to this, and may be formed inside the shaft main body 52. For example, in the shaft 90 of the fifth embodiment shown in FIG. 7, the shaft main body 92 is formed in a cylindrical shape, and a multiple cylindrical member 94 is inserted therein. The multi-cylindrical member 94 includes an input side cylindrical member 96 and an output side cylindrical member 98. The input side cylindrical member 96 includes a cylindrical portion 96A and a cylindrical portion 96B, and the output side cylindrical member 98 includes a cylindrical portion 98A and a cylindrical portion. A portion 98B is provided. The innermost cylindrical portion 98B may be cylindrical. In addition, it is preferable to provide some viscous material sealing means such as a labyrinth structure at the tip of the innermost cylindrical portion 98B.

  Only the input side end of the cylindrical portion 96A and the cylindrical portion 96B of the input side cylindrical member 96 is fixed to the inner peripheral surface of the input side end of the shaft main body 92, and the output side end is not fixed. ing. Only the output side end of the cylindrical portion 98A and the cylindrical portion 98B of the output side cylindrical member 98 is fixed to the output side end portion of the shaft main body 92 via the connecting member 53, and the input side end portion is not fixed. It is in the state. In addition, it is preferable to provide some viscous body sealing means such as a labyrinth structure at the end on the input side. Further, the input side cylindrical member 96 may directly fix the cylindrical portion 98 </ b> A and the cylindrical portion 98 </ b> B to the output side end portion of the shaft main body 92 without using the connecting member 53.

  The multi-cylindrical member 94 has a cylindrical portion 96A, a cylindrical portion 98A, a cylindrical portion 96B, and a cylindrical portion 98B with a diameter decreasing in this order, and cylindrical sealed spaces Y1, Y2, and Y3 are formed between them. . A cylindrical enclosing space X is formed between the cylinder portion 96A and the shaft body 92. The enclosure spaces Y1 to Y3 and the enclosure space X are filled with a viscous material and sealed by a disk-shaped sealing member 98D provided at the tip of the cylindrical portion 98B. Also in the case of the shaft 90 configured in this way, since the cylindrical enclosing spaces Y1 to Y3 in which the speed difference between the inner peripheral surface and the outer peripheral surface is substantially uniform are formed, a large damping effect can be obtained. .

  In addition, although embodiment mentioned above was formed so that enclosure space X and enclosure space Y1-Y5 could each be connected, it is not limited to this, You may divide each enclosure section X and Y1-Y5. Moreover, although embodiment mentioned above sealed the same viscous body in all enclosure space X and Y1-Y5, it is not limited to this, For example, you may make it enclose the viscous body from which a viscosity differs.

  Moreover, although embodiment mentioned above is an example which applied this invention to the engine test apparatus, this invention is not limited to this, You may apply to the shaft for other power transmission.

  DESCRIPTION OF SYMBOLS 10 ... Engine test apparatus, 12 ... Engine, 14 ... Dynamometer, 16 ... Dynamo control part, 18 ... Engine control part, 20 ... Control apparatus, 34 ... Shaft member, 50 ... Shaft (of 1st Embodiment), 52 ... shaft body, 53 ... connecting member, 54 ... multiple cylindrical member, 56 ... input side cylindrical member, 56A to 56C ... cylinder part, 58 ... output side cylindrical member, 58A to 58C ... cylinder part, 58D ... sealing member, 60 ... shaft (of the second embodiment), 64 ... (multiple cylindrical member) of the (second embodiment), 70 ... shaft (of the third embodiment), 74 ... (multiple cylindrical member of the third embodiment) 80 ... (fourth embodiment) shaft, 84 ... (fourth embodiment) multi-cylindrical member, 90 ... (fifth embodiment) shaft, 92 ... (fifth embodiment) shaft Main body, 94 (fifth embodiment) ) Multi-cylindrical member, 96... (In the fifth embodiment) input side cylindrical member, 96A to 96B... (In the fifth embodiment) cylindrical portion, 98... (In the fifth embodiment) output side cylindrical member, 98A to 98B ... (fifth embodiment) cylinder, 98D ... (fifth embodiment) sealing member

Claims (4)

A shaft body for transmitting power;
A plurality of cylindrical members arranged so that the center line coincides with the shaft body,
The multiple cylindrical members include a first cylindrical member in which only one end is fixed to one end of the shaft main body, and only one end is fixed to the other end of the shaft. And a second cylindrical member, and a viscous material sealing space is formed in a cylindrical shape between the first cylindrical member and the second cylindrical member.   2. The power transmission shaft according to claim 1, wherein a plurality of the first cylindrical members and the second cylindrical members are alternately provided, and a plurality of enclosure spaces for the viscous material are formed.   The viscous body is sealed between the first or second cylindrical member disposed to face the surface of the shaft main body and the surface of the shaft main body. The shaft for power transmission described in 1.   The power transmission shaft according to any one of claims 1 to 3, wherein the power transmission shaft is a shaft that connects an output shaft of an engine and a rotation shaft of a dynamometer.

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