Honda Giken Kogyo Kabushiki Kaisha

Satoru Narita

Atsuo Ota

Toshinari Mohara

Takashi Shichinohe

Noriaki Takano

Toshiyuki Kubota

Yoshiaki Tsukada

Osamu Suzuki

Hiroyuki Kawakubo

Tatsuo Masuda

Sumiko Fukuzawa

Kenji Okubo

Hiroshi Ohri

Hidenori Yasuda

To easily perform a change between a four-wheel drive operation of a vehicle to a two-wheel drive operation of the vehicle. In a four-wheel buggy having the four-wheel drive specification in which a longitudinally mounted engine with a crank shaft is directed in the longitudinal direction of the vehicular body, an output shaft is divided into a main body portion and a front wheel connection portion. In the case of applying the output shaft structure to the four-wheel drive specification, a male spline formed on a front end portion of the main body portion is fitted in a female spline formed in a rear end portion of the front wheel connection portion. A front end portion of the front wheel connection portion projects forwardly from an outlet portion of a front case cover, and is connected to a front wheel propeller shaft. On the other hand, in the case of applying the output shaft structure to the two-wheel drive specification, the output shaft composed of only the main body portion to which the front wheel connection portion is not connected, can be commonly used, and the outlet portion of the front case cover may be left as cast, that is, without formation of the through-hole. Accordingly, it is possible to easily perform a change between the four-wheel drive specification and the two-wheel drive specification by commonly using the power unit case, except that only the front case cover requires a slight modification for the four-wheel drive specification.

Output shaft structure for shaft drive vehicle

A transmission for changing a ratio of a rotational number of a power source and a rotational number of an output shaft by shifting a gear train provided between the power source and the output shaft by moving a shift fork. The transmission includes a shift drum for moving the shift fork, a clutch provided between the power source and the gear train, a shift spindle for urging the shift drum and the clutch. When the shift spindle is pivoted, lift of a clutch is started by pivoting a clutch arm. In accordance with pivoting the shift spindle, a sub arm is pivoted and preload is applied on a master arm by a preload spring. Thereafter, when the sub arm is further pivoted, the master arm follows the sub arm and a shift drum is pivoted via index pins. Since the preload is applied, when the clutch is disengaged, the shift drum is pivoted immediately, a shift fork is displaced and gears are switched.

Transmission

A crank case is divided in the longitudinal direction into a front case and a rear case. The front and rear cases are fastened to each other with bolts. A bolt hole through which the bolt passes has a diameter larger than that of the bolt. The bolt hole forms part of an oil passage. The connection end plane on the front case side has an oil groove extending from the right end side to the left end side of the connection end plane. The oil groove is in communication with a communication port at the right end of the connection end plane, and is in communication with an oil passage formed around a bolt at the left end of the connection end plane. With this construction, it becomes easy to form an oil passage in a crank case which is divided into two parts in the longitudinal direction without the need of provision of any special piping.

Lubricating device for internal combustion engine

An intake port and an exhaust port are formed without changing a passage sectional area or its shape a little and without increasing an entire height of an engine. A seat machining part of a valve guide fixing seat of the intake port and the exhaust port are arranged at the cylinder head and are bent in any one of the right side direction or the left side direction as seen from the center of the valve. With such an arrangement, a minimum thickness for the seat machining can be assured, the intake port and the exhaust port do not change the passage sectional area or the sectional shape a little and so it is not necessary to increase the entire height of the engine.

Cylinder head structure of internal combustion engine

The transmission includes a number of male dowels disposed on gear shifters for engaging female dowels on gears. The male dowels are arranged in sets of high and low male dowels, the high and low male dowels being alternately arranged on a side surface of a gear shifter. The male dowels have curved engaging surfaces for engaging respective female dowels. The contact point between the male dowels and the female dowels is radially outward from a radial center of the male dowels, so that a thicker portion of the male dowels absorbs the impact between male and female dowel. The low male dowels need not be machined, which reduces the cost of producing the transmission.

A power unit includes an engine portion and a transmission portion. The bottom portion of a crankcase of the power unit is formed into a shape, in which the right and left sides thereof are tilted downwardly toward a central portion. A main shaft, a counter shaft, and an output shaft of a transmission chamber are disposed one above the other on a right side of a crankshaft. An oil tank is disposed on a right side of the transmission. A bulkhead divides the transmission chamber from the oil tank. The oil tank is formed into an approximately crescent shape with its lower end extending under the output shaft. A suction port of a feed pump is provided in the lowest portion of the crescent shaped oil tank. An oil inlet is provided directly over the oil tank. An overflow hole for allowing oil to overflow into a transmission chamber is provided in the bulkhead. An oil pump is provided in the crank case on the left side of the crank shaft. A scavenging pump pumps up oil from an oil sump located at the lowest portion of the bottom of the crank case. A drain hole, provided in a lower portion of the crank case, communicates to both the oil tank and the transmission chamber. The drain hole is plugged with a drain bolt.

A power unit, including an engine and a transmission, is transversely arranged in a vehicle with a crankshaft arranged parallel to a traveling direction of the vehicle. Looking at a crankcase from the front, a camshaft is arranged to one side of the crankshaft. A balancer shaft is also located on the one side of the crankshaft and coaxailly drives an oil pump. The transmission and an oil tank are arranged on the opposite side of the crankshaft. The crankshaft includes a crank sprocket which drives the cam shaft via a cam chain and a cam sprocket provided on one end of the cam shaft. The cam sprocket and the oil pump are arranged on either side of a balancer attached to the balancer shaft. The power unit arrangement allows for an increase in the potential capacity of the oil pump of a dry sump type lubrication system without causing an increase in the size of a crankcase.

Accessory arrangement structure for internal combustion engine

Looking from a front toward a rear of a vehicle, a crankcase has a cross sectional shape which gets narrower towards its bottom. The crankcase includes a crankshaft which extends parallel to a direction of travel for the vehicle. A main shaft, a counter shaft and an output shaft of a transmission are arranged in a transmission chamber on one side of the crankshaft. An oil tank is provided on the same side of the crankshaft and outwardly of the transmission chamber. The oil tank is separated from the transmission chamber by a partitioning wall. The oil tank has a substantially crescent shape, with the lower end extending beneath the output shaft. An intake port of a feed pump is provided in the lowest part of the oil tank. An oil inlet for adding oil to the oil tank is provided just above the oil tank. An overflow hole to the transmission chamber is provided in the partitioning wall. The feed pump is provided on an opposite side of the crankshaft inside the crankcase. A scavenge pump, which sucks from an oil sump at the lowest section of the crankcase and returns oil to the oil tank, is also provided on the opposite side of the is crankshaft and inside the crankcase. A drain hole communicates with the oil tank and with the transmission chamber. The drain hole is provided in a lower part of the crankcase and is closed by a drain bolt.

Lubrication system for internal combustion engine

An electric-power-assist transmission and a shift control method which allow good operability to be obtained. In the shift control method, a sleeve is engaged with a target gear. A shift spindle is rotated by a driving motor in order to move the sleeve along a main shaft by using a shift fork and a shift drum interlocked with the shift spindle. When the sleeve is moved to a position in contact with the target gear, PWM control is executed at a duty ratio of 70% during the first 20 ms. Thereafter, the PWM control is executed by changing the duty ratio to 50% and restoring the duty ratio back to 70% repeatedly at intervals of 10 ms.

Shift control method for an electric-power-assist transmission

To perform simple and precise shift changes without using a change pedal and a change lever. In conjunction with the engagement and disengagement of a transmission clutch, a shift spindle rotates a shift drum to establish predetermined gear levels, and is rotatably driven via moderator gears by a motor. By operating a shift up switch or shift down switch not illustrated, the motor rotates the shift spindle in a prescribed direction, the transmission clutch and shift drum.

Power transmission device for vehicle

A shift control unit is provided in an electric-power-assist transmission which offers good operatability. A shift disabling unit employs a neutral-position detecting unit, a vehicle-speed judging unit, an engine-rotational-speed judging device, an OR circuit and an AND circuit. The neutral-position detecting unit is used for outputting an 'H'-level signal to indicate that a gear is placed at a neutral position. The vehicle-speed judging unit generates an 'H'-level signal for a speed of a vehicle equal to or higher than 10 km/h. On the other hand, the engine-rotational-speed judging device generates an 'H'-level signal for a rotational speed of an engine equal to or higher than 3,000 rpm. The OR circuit generates an 'H'-level signal when the vehicle-speed judging unit generates an 'H'-level signal or the engine-rotational speed judging device generates an 'H'-level signal. On the other hand, the AND circuit generates an 'H'-level signal when the neutral-position detecting unit generates an 'H'-level signal and the OR circuit also generates an 'H'-level signal. With the AND circuit outputting the 'H'-level signal, the shift disabling unit prevents a shift change from being made.

Shift control unit of electric-power assist transmission

High-temperature oil returning from a cylinder head is to be prevented from being sucked directly into an oil pump through an oil strainer. An oil intake space is defined by partition walls formed near a split plane of both a front casing and a rear casing. The interior of the oil intake space is partitioned into a lower oil chamber and an upper oil chamber by an oil strainer. The lower oil chamber is in communication with the interior of an oil pan through intake ports, while the upper oil chamber communicates with an oil pump. The oil strainer is separately formed as an intake duct and a screen. The oil strainer is fitted and held in a slot formed in the partition wall.

Oil intake structure of an engine

A structure for blocking an oil supply hole of a kick idle gear bearing portion is provided in an internal combustion engine of a type wherein a kick starting mechanism is removably mounted for transmitting an input from a kick arm to a crank shaft by way of a kick idle gear rotatably supported by a counter shaft. When the kick starting mechanism is removed and a self stating mode is set, an oil supply hole of a bearing portion in the state that the kick idle gear of the counter shaft is removed is blocked by a blocking member having a slip preventive function. The blocking member includes an insertion portion inserted in the oil supply hole, and an abutment portion integrally formed with the insertion portion, which is abutted on the outer peripheral surface of the bearing portion.

Growing community of inventors

Saitama, Japan

Satoru Narita