JP2000314324A - Method for applying preload to circulating drive element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably hold a preload at all times by deciding a parameter in relation to a vibration behavior of an internal combustion engine and/or a circulating drive element on the basis of at least one of sensor output, and controlling a tensioner for applying a prescribed preload in compliance with the parameter. SOLUTION: In an engine block 1, a camshaft driving device 2 is disposed on a surface and is constituted, so as to transmit rotation of a crankshaft chain gear 5 to camshaft chain gears 3, 4 via a chain 6. In this case, a fixed guide rail 7 is disposed on one side of the chain 6 between the chain gears 4, 5, and a contact pressure rail 9 is disposed slidably on one side of the chain 6 between the chain gears 3, 5. The contact pressure rail 9 is pushed to the chain 6 by a tensioner 10 for being controlled in compliance with parameters, such as the speed of an engine and the torque so as to obtain a desired preload of the chain 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tension device,
More particularly, the present invention relates to a method of applying a preload force to a circulation drive element, particularly a chain of an internal combustion engine, by a chain tensioner.

[0002] The invention further relates to an apparatus for performing the method.

[0003]

BACKGROUND OF THE INVENTION In order to meet particularly high temperature requirements, chain drives, for example for driving camshafts, are commonly used today in many internal combustion engine constructions. For example, in an internal combustion engine having two overhead camshafts, the chain is guided by a chain gear connected to the crankshaft or two adjacent camshaft chain gears. To reduce vibrations, the chain is exposed as much as possible, and the chain is usually guided on one side along stationary slide rails of a suitable sliding material. A movable contact pressure rail pressed against the chain by a chain tensioner is arranged opposite the stationary slide rail.
There are many different chain tensioner designs that are to meet the various requirements made in use. For example, chain tensioners are known which apply their preload force with the aid of expansion elements to compensate for temperature changes. In general, chain tensioners are based on the principle of a combination of a preload applied by a spring element and a damping effect provided by a hydraulic structure. It is also known that damping means is coupled to the engine oil circuit to achieve faster and more powerful damping.
Thereby, the preload force predetermined by the spring means is affected only to a limited extent. It is therefore an object of the present invention to provide a method and a device of the above type for improving the vibration behavior of driving elements, especially chains, in internal combustion engines.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a system in which a parameter relating to the vibration behavior of an internal combustion engine or a circulating drive element is determined by at least one sensor and a tension device provides sensor data for applying a predetermined preload force. This is achieved with the method according to the invention in that it is controlled electrically in consideration of This means that the vibration behavior of the internal combustion engine and / or the circulation drive element is monitored and the preload force is increased or decreased in response. In particular, within the range of the resonance frequency of the internal combustion engine, for example, strong vibrations of the chain can be avoided by increasing the preload force. In particular, according to a variant, it is useful to increase the preload force at increasing speed, and other factors can be taken into account here further.

[0005] For this reason, it is further preferred that one or more characteristics of the internal combustion engine be determined by at least one sensor. The property is preferably a standard property of speed and / or load, especially torque, or parameters derived therefrom. Engine vibration itself can also be measured by an acceleration sensor.

[0006] The invention also refers to a device for applying a preload force to a circulating drive element of an internal combustion engine, in particular a chain. This device is an electrically controllable tension device,
In particular, a chain tensioner, a tensioning device for receiving sensor data on the vibration behavior of the internal combustion engine and / or the circulating drive element, especially the chain, and for applying a predetermined preload force according to the sensor data,
Especially a control unit for controlling the chain tensioner. This means that the device changes, for example, the preload force of the chain tensioner according to a predetermined plan. As a result, the device according to the invention positively influences, for example, the oscillating behavior of the chain drive, thereby ensuring an optimal chain tension at a given operating time. The tensioning device must be configured such that it can actively adjust the preload force based on the control signal.

The force adjusting operation itself is performed electrically or, for example, hydraulically, depending on the respective application.

In order to keep the number of additional components as low as possible in comparison with a conventional internal combustion engine, according to a further embodiment, the control unit is connected to an electronic engine device of the internal combustion engine that supplies sensor data. It is useful to summarize and / or. In general, modern vehicles are equipped today with an engine control unit which already determines all operating data, in particular with regard to characteristic maps. The vibration behavior of the engine is directly estimated from the above values. Then, for example, the chain tensioner can be controlled according to the data. Thus, a configuration of a chain tensioner is conceivable which is just connected to the electronic engine device by a supply line, whereby an automatic connection with a suitable sensor takes place.

It makes sense to use a control loop to react as quickly as possible at all times and to monitor the preload force permanently. For this purpose, control means are provided for controlling the preload force in response to the sensor. Further, it may be necessary to measure, for example, either the applied force of the chain tensioner itself, or the preload distance (or associated path) spanned by the chain tensioner.

[0010] Although the tensioning device can also be operated pneumatically, hydraulically, mechanically or thermally (eg by means of telescoping elements), the chain tensioner is, in one embodiment, preloaded. Actuated by an electric regulating device for regulating the pressure. Thus, the sensor signal can be used, for example, to directly control an electric adjustment mechanism or a lifting mechanism.

[0011]

1 shows a schematic representation of an engine block 1, on the front of which a camshaft drive 2 is arranged. The camshaft drive 2 is usually
It is covered by a cover or arranged in the passage of the engine block 1 and is shown here in an open state for simplicity. The crankshaft drive includes two crankchain gears 3, 4 and a crankshaft chain gear 5 positioned underneath. The control chain 6 meshed with the teeth of the chain gears 3, 4 and 5 is around the chain gears 3, 4 and 5. The stationary guide rail 7 is disposed on the right side, and the contact pressure rail 9 that can rotate about the pivot shaft 8 is disposed on the left side. The contact pressure rail 9 is
Is pressed against the control chain 6 with a predetermined force by the chain tensioner 10 so that the desired preload is obtained. The illustrated chain tensioner 10 is electrically operated, and an electronic control unit 11 controls the expansion and contraction of the contact pressure plunger 12 appropriately. The electronic control unit 11 receives a signal by a line 13 from the electronic engine unit 14. Wireless or infrared transmission or the like may be provided from the electric engine device 14 to the electronic control device 11. The electronic control unit 11 may also be mounted in another suitable place or may be combined. Electronic engine device 14 accepts engine characteristics, temperature, and other data.

In particular, the characteristics are now communicated to the electronic control unit 11 and processed there. In response to the signal, the electronic control unit 11 controls the chain tensioner 10 to adjust the preload force of the chain 6. In particular, the range of the resonance frequency in the electronic control unit or in other regions that are subject to vibration can be determined on the basis of the characteristics, so that the preload can be applied in a suitable manner. The very rapid control of the chain tensioner 10 also eliminates the need for damping means. Strong impacts caused by driving the motor vehicle can also be compensated for thereby. In such a case, an acceleration sensor for sending data to the electronic control system 11 should be additionally provided. The electronically controlled chain tensioner 10 is an active chain tensioner that can change both the driving force and the damping rate.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a chain tensioner of the present invention relating to an internal combustion engine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine block 2 camshaft driving device 3 crank chain gear 4 crank chain gear 5 crank chain gear 6 chain 7 stationary guide rail 8 pivot shaft 9 contact pressure rail 10 chain tensioner 11 control unit 12 contact pressure plunger 13 wire 14 electronic engine device

Claims (7)

[Claims] 1. A method for applying a preload force to a circulating drive element of an internal combustion engine, in particular a chain (6), by means of a tensioning device, in particular a chain tensioner (10), the vibration behavior of the internal combustion engine and / or the circulating drive element. Said method wherein the tensioner (10) is controlled in view of the sensor data to apply a predetermined preload force. 2. The method according to claim 2, wherein one or several characteristics of the internal combustion engine are determined by at least one sensor. 3. The engine according to claim 1, wherein the speed and / or the load, in particular the torque, of the internal combustion engine are determined as characteristics.
Or a method according to claim 2. 4. A device for applying a preload force to a circulating drive element of an internal combustion engine, in particular a chain (6), comprising an electrically controllable tensioner, in particular a chain tensioner (1).
0) and a control unit for receiving sensor data relating to the vibration behavior of the internal combustion engine and / or the circulation drive element and for controlling the tensioner (10) to apply a predetermined preload force in response to the sensor data ( 11). 5. An electronic engine device (1) for an internal combustion engine, wherein a control unit (11) supplies sensor data.
Device according to claim 4, characterized in that it is connected to and / or combined with 4). 6. The device according to claim 4, further comprising a control loop for controlling the preload force in response to the sensor data. 7. The device according to claim 4, wherein the tensioner is actuated by an electric adjusting device for adjusting the preload force.