RU31418U1 - Hydraulic device for tensioning the chain or belt of the engine timing - Google Patents

Description

2003107117

Hydraulic device for tensioning the timing chain or belt of the engine timing mechanism.

The utility model relates to mechanical engineering, in particular engine manufacturing, and can find application in devices for changing the tension of the drive element (chain, belt) of the gas distribution mechanism of an internal combustion engine (ICE), in shock absorbers of vehicles.

A device is known for tensioning a drive element (chain or belt) of a gas distribution mechanism of an internal combustion engine of automobiles manufactured by AvtoVAZ, see V. Vershigora and others. Automobiles VAZ, M ,, Transport, 1973, p. 43, comprising a housing, in the inner cavity of which a spring-loaded plunger with an internal recess is installed, and a spring-loaded rod located in the plunger, equipped with a bulge and washer mounted on the rod.

In the known device, the absorption of the disturbing force from the drive element (chain or belt) in the first stage occurs due to the compression of the plunger spring, in the second stage - due to the compression of the rod spring by the size of the gap between the end of the thickening of the rod and the bottom of the plunger, in the third stage, the bottom of the plunger hits at the end of the thickening of the rod, from which the end of the thickening of the rod is always brilliant from shock.

IPC F16H 7/08

automatically reached a value equal to the impact force of the drive element in a given

moment.

For soft shock absorption, it is necessary that the buffer stroke be more than 1 mm, but not more than 2.5 mm, in order to prevent the drive element from slipping along

asterisks, which would lead to deregulation of the gas distribution mechanism

(Timing) in phases and engine failure.

The spring of the rod, returning from the compressed state to its original initial position, delivers a percussive vibrational impulse to the drive element through the washer, plunger, shoe, amplifying its vibrations. The time for applying a disturbing pulse to the drive element directly depends on the size of the buffer stroke: with an increase in the buffer stroke, the operation of the device deteriorates. The known device, instead of damping the vibrations of the drive element, delivers a disturbing vibrational pulse to the drive element, amplifying the vibrations.

At the moment when the perturbing pulse supplied to the drive element from the running engine (the frequency of the supplied pulse depends on the engine speed) coincides in frequency with the frequency of the natural vibrations supplied from the tensioner (each engine has its own specific speed range), a resonant phenomenon arises, which sharply increases the oscillation amplitude of the drive element, enhances shock, enhances the wear rate of timing parts, destruction of individual parts is possible, the amount of harmful engine operation increases, ivayutsya engine noise and unevenness of the cam shaft rotation, which increases the offset from the nominal location of the timing phase.

The resonance phenomenon in the timing drive element always occurs when the engine speed in the stage of reduction or increase passes through the resonant speed range.

Also known is the tensioner of the drive element of the gas distribution mechanism of the internal combustion engine, described in A.S. USSR No. 1038657, MKI F16H 7/08, publ. 08/30/83, bull. No. 32, comprising a housing, in the inner cavity of which a spring-loaded plunger with an internal recess is installed, and a spring-loaded rod located in the plunger, provided with a bulge and a washer mounted on the rod. The housing is equipped with a channel for supplying fluid to its internal cavity, and the washer is made stepped in internal diameter, and the larger diameter of the stepped surface covers the thickening of the rod with

the formation of an annular gap.

The disadvantages of the described device in the first place include

the complexity of its design, due to a significant number of its constituent elements. In addition, the oil supply to the tensioner housing does not

provided by special means, and carried out by oil

t into the channel when the engine runs by gravity, while at the initial moment of operation

there may be no oil in the tensioner housing or its quantity may be insignificant, which at the initial stage of engine start-up and operation inevitably leads to a hard contact between the rod and the plunger (hammer effect), which ultimately leads to an increased drive noise and progressive wear of engine parts . For the above reasons, the described design of the tensioner has not found industrial applications in the production of engines at the Volga Automobile Plant.

The closest adopted for the prototype is the tensioner described in the certificate for utility model No. 9914, MKI F16H 7/08, publ. 05/16/99, bull. No. 5, comprising a housing, in the internal cavity of which a spring-loaded plunger is installed with axial fixation means, inside the housing cavity communicating with the working fluid supply channel, a compensation chamber is formed, communicating with the working chamber by means of a valve assembly. The supply of working fluid to the valve body of the valve assembly is made by two communicating axial and radial channels. The compensation chamber is equipped with a drainage channel communicating its cavity with the external environment, and a displacer in the form of a rod is located in the working cavity.

The design of the device described above allows the supply of working fluid to the tensioner housing using additional products directly from the engine lubrication system, from where oil under pressure enters the device housing to ensure shock-free operation of the tensioning device of the engine timing gear drive. However, the presence of products that provide an external supply of working fluid makes it more expensive and complicates the design of the gas distribution mechanism and places increased demands on the reliability of the products for supplying working fluid and their connections (since oil leaks at the joints are possible).

supply of working fluid to the tensioner in the specified installation dimensions while maintaining the operating parameters of the tensioner.

The technical problem is solved by changing the place of oil supply to the tensioner housing.

To solve the problem in a hydraulic tensioning device

timing chain or timing belt of an internal combustion engine,

comprising a housing with a connecting flange and a working fluid supply channel, in the internal cavity of which a spring-loaded plunger is installed with fixation means in the axial direction, compensation and working chambers are formed in the internal cavity of the housing, communicating with each other by means of a valve assembly, in the axial channel of which a spring-loaded spherical shut-off valve is installed body, the supply of working fluid to which is made by two communicating axial and radial channels, the compensation chamber is equipped with a drainage a channel, and a displacer in the form of a rod is located in the working chamber, the compensation chamber is located in the inner cavity of the plunger, the plunger contains an outer diametric groove for supplying the working fluid connected by a radial hole to the compensation chamber, and a drainage channel communicating the compensation chamber with the internal cavity of the engine through a plane the platform for the axial fixation means, made in the form of a restrictive pin, which simultaneously prevents the plunger from turning in the housing, The orientation of the radial holes. The housing of the device is additionally equipped with an external diametrical groove bounded by sealing rings and connected by a channel for supplying a working fluid with an internal diametrical groove in the housing in communication with the external diametrical groove on the plunger. The valve assembly is installed in the inner cavity of the plunger and has a groove for orienting the radial channel for supplying the working fluid relative to the locking element when assembling the tensioner.

The placement in the proposed design of the compensation chamber in the inner cavity of the plunger allows for the supply of working fluid directly from the channel of the engine lubrication system without additional devices, which simplifies the design of the timing and increases the reliability of its operation, and also increases the volume of the compensation chamber of the tensioner without increasing the overall dimensions of the latter, which softens tensioner operation at the initial moment of engine operation. The placement of the compensation chamber in the inner cavity of the plunger allowed

increase the size of the plunger without increasing the overall dimensions of the device, and therefore increase the contact area of the plunger with the tensioner housing, which

allows to reduce the skew of the plunger in the device during operation of the latter, thereby reducing wear of parts and to increase reliability and

durability of the tensioner. Compensating fluid supply

the tensioner chamber is carried out through a system of communicating

diametral grooves and holes, which ensures the supply of working fluid into the internal cavity of the device at any position of the plunger.

The design of the claimed utility model is shown in FIG. 1.

The inventive device comprises a housing 1 with a connecting flange and a channel 2 for supplying a working fluid, in the inner cavity of which a plunger 3 is installed with a spring 4 and with means 5 for fixing in the axial direction. In the internal cavity of the housing 1, a compensation chamber A and a working chamber B are formed, communicating with each other by means of a valve assembly 6, in the axial channel 7 of which a spherical locking element 8 is installed, which is pressed by the spring 9. The fluid is supplied to the locking element 8 by two communicating channels - axial 7 and radial 10. Compensation chamber A is equipped with a drainage channel 11, and in the working chamber B is a displacer 12, made in the form of a rod. The compensation chamber A is located in the inner cavity of the plunger 3. The plunger 3 contains an outer diametrical groove 13 for supplying a working fluid connected by a radial hole 14 to the compensation chamber A, and a drainage channel 11 communicating the compensation chamber A with the internal cavity of the engine through a plane platform 15 under axial locking means 5, made in the form of a restrictive pin, which not only restricts the movement of the plunger 3 inside the housing 1 along the axis, but also prevents rotation from the plunger 3 in the housing 1 around its axis, thereby providing orientation holes 14 and channel 11 in the upper position. The housing 1 of the device is additionally equipped with an external diametrical groove 16, limited by the sealing rings 17 and connected by a channel 2 for supplying working fluid with an internal diametrical groove 18 in the housing 1, communicating with the external diametrical groove 13 on the plunger 3. The valve assembly 6 is installed in the inner cavity of the plunger 3 and has a groove 19 for the orientation of the radial channel 10 for supplying the working fluid relative to the locking element 8 during installation.

The device operates as follows.

At the time of start-up after assembly of the device (when there is no working fluid in the device case), oil from the channels of the engine lubrication system under pressure enters the outer diametrical groove 16 of the device body 1, from which through the channel 2 for supplying the working fluid to the cavity formed by communicating

the diametrical grooves: the inner 18 of the housing 1 and the outer 13 of the plunger 3, then through the radial hole 14 in the plunger 3 into the compensation chamber A. From the compensation chamber A through channels 7 and 10, the working fluid flows to the shut-off element 8 and exerts pressure on it. Due to the pressure difference, the shut-off member 8 moves away, compressing the spring 9, and the oil flows into the working chamber B. The air contained in the oil is removed from the chamber A through the drainage channel 11, and from the chamber B through the gap between the housing 1 and the plunger 3. To accelerate the filling of the chamber B and bring the device into working condition, a displacer 12 having the form of a rod is placed inside the working chamber B.

Workflow - ensuring chain (belt) tension and shock damping. The chain (belt) of the drive of the internal combustion engine mechanisms acts through the baschmak of the tensioner on the plunger 3, moving it in the housing 1 of the device. When moving the plunger 3 inside the housing 1 in the working chamber B, the pressure of the working fluid increases. Due to the difference in pressure in chambers A and B, the shutoff member 8 of the valve assembly 6 overlaps the axial hole 7 for supplying the working fluid, and further movement of the plunger 3 under load occurs due to the overflow of the working fluid through the diametrical clearance between the housing 1 and the plunger 3. shock damping occurs, transmitted to the plunger from the drive element. When the chain (belt) moves away from the tensioner, the spring 4 after it moves the plunger 3. When the plunger 3 leaves the housing 1, the pressure of the working fluid in chamber B drops, and in chamber A increases. Due to the resulting pressure difference, the shut-off element 8 opens, because the force of the spring 9, pressing the locking element 8, is incomparably small in relation to the force from the application of the pressure difference of the working fluid, and the working fluid under pressure fills the working chamber B.

When the engine is stopped for a long time, the working fluid flows from chamber B into the internal cavity of the engine, but the amount of working fluid necessary for the start-up period before the oil arrives under the working pressure from the oil pump is stored in chamber A.

in order to optimally use the volume of the compensation chamber A, channel 10 for communication with camera B is located at the bottom.

Thus, the use of the proposed design will improve the efficiency and reliability of the engine timing due to

simplifying the design of the supply of working fluid to the chain tensioning device in

% of the specified installation dimensions while maintaining operating parameters.

Claims (1)

A hydraulic device for tensioning a chain or a belt of the engine gas distribution mechanism, comprising a housing with a connecting flange and a working fluid supply channel, in the inner cavity of which a spring-loaded plunger is installed with fixation means in the axial direction, a compensation and working chambers are formed in the inner cavity of the housing, communicating with each other by valve assembly, in the axial channel of which a spring-loaded spherical locking element is installed, the supply of working fluid to which is performed two communicating axial and radial channels, the compensation chamber is provided with a drainage channel, and a displacer in the form of a rod is located in the working chamber, characterized in that the compensation chamber is located in the inner cavity of the plunger, the plunger contains an external diametrical groove for supplying the working fluid, connected by a radial hole with compensation chamber, and a drainage channel communicating the compensation chamber with the internal cavity of the engine through a flat platform under the fixing means in the axial direction In the form of a restrictive pin, which simultaneously prevents the plunger from turning in the housing and ensures the orientation of the radial holes, the device housing is additionally equipped with an external diametric groove bounded by sealing rings and connected by a working fluid supply channel with an internal diametrical groove in the housing, which communicates with the external diametrical groove on the plunger, and the valve assembly is installed in the inner cavity of the plunger and has a groove for orienting the radial channel and the working fluid relative to the locking body when assembling the tensioner.