Viewing 1 to 16 of 16
Technical Paper
Makoto Hatano, Masaya Otsuka, Chiyota Ogata, Naoto Suetsugu, Takashi Amemiya, Masashi Kudo
Technical Paper
Masashi Nakao, Chiyota Ogata, Naohito Suetsugu, Shigeyuki Ono
This paper addresses the temperature dependence of friction properties in seals (O-rings and D-rings) for use in reciprocating motions. The narrower focus here is on several factors: the effects of a lubrication state, the change in dimension and the physical properties of a rubber material. It can be assumed that they influence the temperature dependence of a frictional force. As shown in this study, A frictional force has a profile characterized by temperatures. It is revealed that the profile of a frictional force is mainly attributable to the deformation of a rubber material in motion-the physical properties (elastic modulus) of a rubber materials-and the rate of recovery in elasticity of a rubber material. In addition, a temperature showing the maximum frictional force is largely attributable to the low-temperature properties of a rubber material. It is revealed that the temperature dependence of a frictional force is mainly influenced by the material properties of rubber.
Technical Paper
Jaewook Kang, Shuichi Imai, Manshu Kameike
Leakage occurs between contact surfaces due to the surface roughness. In general, soft materials such as rubber are used to perform a sealing function. Softmetal used as an engine seal material, is a stainless steel plate coated with rubber. In order to seal a fluid, it is necessary to design the rubber coating and the contact pressure with consideration of the surface roughness. In this study, leak tests are conducted with the softmetal, and the effects of contact conditions, such as surface roughness, load, rubber thickness and rubber material are investigated. A differential pressure system using nitrogen gas was constructed for the leak test, and a surface of anisotropic roughness is adopted. The size of the clearance due to the geometrical shape of surface asperities is calculated from an indentation test. A model of rubber compliance to surface asperities is proposed, which predicts the sealing contact pressure with the rubber thickness.
Technical Paper
Yoshinori Yamaguchi, Daihachi Shojima, Chiyota Ogata, Kenji Oya, Kuniyoshi Kawasaki, Masashi Kudo
Technical Paper
Norimasa Hosonuma, Hidenori Arai, Yuuichi Shutou, Nozomu Suzuki, Hirotaka Mizuta
We developed a measurement method to evaluate the sealing performance for narrow gap between a metal shaft and a fitted sleeve quantitatively in a brief time. We examined the effect of the chamfer shape and the surface roughness of the shaft on the leakage rate. We also conducted liquid leakage test in order to compare the leakage rate of gas with that of the liquid. From this comparison, we showed that it is possible to evaluate the sealing performance for liquid by measuring leakage rate of gas. In addition, we discussed the leakage rate of fluid through the gap by assuming viscous flow. The estimated leakage rate of the liquid derived from the leakage rate of air by converting viscosity of air into that of the liquid was totally proportional to the measured leakage rate of the liquid. Therefore, we concluded that the leakage rate of liquid can be estimated by measuring that of air.
Technical Paper
Satoshi Ohkawa, Yutaka Touji, Genroku Sugiyama, Tsunejiryo Seno, Kimihiko Ogura, Hiroshi Ishiyama, Hiroyasu Kodera, Masato Nagao, Hitoshi Hamaguchi, Hiroaki Tauchi, Shinichi Mitsumoto, Yoshitaka Shiraga, Akihiro Mochizuki, Masao Seki, Hirohiko Ootsu, Hirohito Hasegawa, Hironori Nishina, Hiroshi Kosodo, Tomoki Ando, Nobuhiko Shizuka
Hydraulic fluid (HF) specifications for mobile construction equipment called JCMAS HK and HKB have been established by the Fuels and Lubricants Committee of Japan Construction Mechanization Association (JCMA). The specifications are designated by two viscosity categories of single grade and multigrade. Each category has ISO viscosity grade (VG) 32 and 46. The JCMAS HK oils are recommended for use in hydraulic systems designed at pressure up to 34.3MPa(5000psi) and to heat hydraulic fluid up to 100 °C. These oils also provide wear control, friction performance, oxidation and rust protection, seal swell control and filterability performance. Two piston pump test procedures were developed to evaluate lubricating performance of these oils under high pressure conditions. The JACMAS HKB oils are classified as environmentally friendly oils due to the additional requirement for biodegradability.
Technical Paper
Tsunejiryo Seno, Satoshi Ohkawa, Genroku Sugiyama, Kimihiko Ogura, Hiroshi Ishiyama, Yutaka Touji, Hiroyasu Kodera, Masato Nagao, Hiroaki Tauchi, Hitoshi Hamaguchi, Shinichi Mitsumoto, Takahiro Ozaki, Minoru Nakamura, Kiyoshi Takeuchi, Yoshitaka Shiraga, Akihiro Mochizuki, Masao Seki, Hirohito Hasegawa, Hironori Nishina
Since construction machinery manufacturers recommend various brands and types of greases for their machinery, customers would benefit from a standardized grease which can be used in all construction machinery. Furthermore, construction machinery manufacturers have many experiences of field problems caused by commercially available and commonly used EP Lithium greases. Therefore, the Fuels and Lubricants Committee of Japan Construction Mechanization Association (JCMA) has developed a new grease specification called “Japan Construction Mechanization Association Specification (JCMAS) GK,” for construction equipment. The JCMAS GK includes requirements for National Lubrication and Grease Institute (NLGI) No. 1 and No. 2 consistency grades. The JCMAS GK greases have enough lubricating properties for periodical grease fitting of most construction machines, hydraulic excavators, bulldozers and wheel loaders. The JCMAS GK greases are applicable from -20 to +130 degrees Celsius.
Technical Paper
Kazunari Seki, Yoshihiro Kuzumaki, Yuki Sato, Yasuaki Tanabe
Various needle bearings and metal thrust washers are used in automatic transmissions (ATs and CVTs) for automobiles, however, in recent years thrust washers made of engineering plastics are begining to be adopted, because of their superiority in saving space, reducing weight and cost. This paper reports the newly developed low friction thrust washer made of engineering plastic for torque converters of AT·CVT.
Technical Paper
Yoshihiro Kuzumaki, Hiroyuki Sato, Chikako Takei, Kazushi Ishikawa, Seiji Nakagome, Shigeyuki Ono
Lubricants such as wax and grease are used to improve adhesion, frictional properties, and sliding noise of thermoplastic elastomer (hereafter referred to as TPE) products used for automotive parts. These lubricants help improve the lubrication of products when added to TPE products or applied directly to the surface. Long-term effectiveness can be expected from the former method due to the gradual movement of the lubricant from the inside to the surface. Clarifying this transfer phenomenon should therefore be very important for predicting and controlling product characteristics. This paper reports on an analysis method applying infrared spectroscopy developed by the authors, and investigations conducted on the surface transfer of lubricants such as wax and grease for polyester TPE used for CVJ boots.
Technical Paper
S. Honda, Y. Sato
One of the demands regarding reciprocating seals is to minimize the leakage from machineries due to global environmental issue. Especially in these years, rising in efficiency and downsizing of the machineries make the operating conditions of the seals severer than ever. Therefore, it becomes more important to know the sealing performance with high accuracy under actual operating conditions. In order to meet the request, a new method based on visualization and spectroscopy is presented. In this paper the description of the technique and the first results obtained with general reciprocating seals are shown.
Technical Paper
Hirotaka Mizuta, Hideyuki Furuyama, Yuki Sato
This paper describes a new measurement method using fluorescence analysis to measure oil pump rates of radial lip seals for small shaft diameters. A test apparatus and operating procedure for measurement of pump rate were shown. First results of pump rates obtained with seals for 8 mm shaft diameter were shown. As a result, the oil pump rates under various shaft speeds and sump pressures ranged from 4 to 160 mg/h.
Technical Paper
Masaaki Kanamori, Hideyuki Tokumitsu
SOFT METAL (SUS plate coated with rubber) is used for cylinder head gasket (CHG). Conventionally, this SUS plate is preprocessed using coating chromate. When this was changed to chrome-free agent, the rubber was peeled off from the plate. There are found that this may be due to the electrochemical reaction caused by the contact between different metals-Al of the engine block and Fe (SUS) of CHG.
Technical Paper
W. Tokunaga, H. Hyakutake, K. Miyake
This paper presents a measuring technique, a test result and a finite element analysis result of a surface temperature of rotary lip seals. A thermocouple embedded in the surface of a shaft and radio transmission systems provide wireless measurement for the temperature of the rotary shaft, which is driven up to 6000 rpm. Relationships between shaft temperature, lip temperature and sliding speed were shown. Torque of PTFE coated seals is about 23 % lower than that of conventional seals at 22 m/s. At that time, the shaft temperature of PTFE coated seals is about 7 K lower than that of conventional seals. And, Lip temperature of PTFE coated seals is about 1 K lower. In the analysis result, high temperature part of the shaft is larger than that of the lip, that is, heat is concentrated in the sealing edge of the lip. Temperature rise of the analysis result is consistent with those of the test result.
Technical Paper
Yohei Miki, Hisao Futamata, Masahiko Inoue, Masashi Takekoshi, Kohbun Yamada
Abstract Unexpected noise may occur around air intake manifold when the throttle valve is quickly opened. In order to solve this problem, mesh is often mounted into the air flow between the intake manifold and the throttle body. In this study the effect of mesh design on the noise reduction was investigated. Several designs of the mesh were tested with an actual automobile and the developed test equipment taking advantage of an intake manifold unit, and the noise attenuation was discussed with measuring the noise and observation of the mesh deformation. Based on those experiments, the mesh design for noise reduction was optimized. Furthermore integration of mesh and rubber gasket was examined. Finally, rubber mesh-gaskets which provide sealing and noise attenuation for air intake has been proposed in this study.
Technical Paper
S. Nakaoka, Y. Sato, T. Yasudomi, T. Takeda
Seal rings are used as shaft seals in automatic transmissions, where they act as a dam to direct pressurized fluid flow to hydraulic circuits. Conventionally, cast-iron seal rings were used, but over the past two decades, this material has been switched to resins like PTFE and PEEK to satisfy performance requirements such as low leakage and low frictional torque. However in using resin seal rings, the shaft sometimes undergoes the so-called three body abrasive wear due to invasion of hard particles, such as wear particles and dust, into the sliding portion between the seal ring and the shaft. To prevent such wear of the shaft, it is important to prevent invasion of hard particles into the sliding portion, and also to promptly discharge hard particles from the sliding portion. We therefore designed a seal ring taking into consideration these needs and investigated its shaft wear reduction effects.
Technical Paper
Masaya Otsuka, Tatsuo Okamura, Naohito Suetsugu, Takashi Ohta, Shigeyuki Ono
This paper reports on a new concept for static seal designs taking into consideration the surface roughness of sealing surfaces. The concept focuses on fluid penetration from the interstices between the seal and counterface caused by surface roughness. In the study, we investigated the relation between the leakage and surface roughness of the sealing surface of the elastomer seal. At the same time, we also analyzed the contact state of the elastomer seal based on the equations of Ishiwata et al. on deformation of elastomer surface into rough surfaces [1]. The micro-leakage testing machine (SMLA) developed by the authors was used to measure micro-leakage at high precision and in a short time [2]. The results showed that the sealing phenomena were related to the ratio of seal surface contact pressure Ps / elastic modulus of seal E, determined by the compression ratio of seals, and does not depend on the chemical structure and hardness of the elastomer used.
Viewing 1 to 16 of 16


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