KR200467402Y1 - Valve train for combustion engine and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a valve train for a multi-cylinder internal combustion engine, in which the valve train is connected to one or more camshafts (1) rotatably supported in one or more camshaft bearings (2, 3) for operation of the gas exchange valve of the internal combustion engine. One or more sliding cams 5 are provided which are able to move axially on the camshaft, the sliding cams 5 being driven to the centering of the sliding cams on the one hand and to the sliding cams on the other hand, despite the possibility of axial movement of the sliding cams. Supported so as to ensure torque transmission, the sliding cam 5 is arranged between the camshaft and the sliding cam 5 and seen in the axial direction through a sliding sleeve 15 which is axially movable on the camshaft. In the intermediate zone 16 of the sliding cam 5, the sliding sleeve 15, which is fixedly connected to the sliding cam 5, is before torque to the sliding cam 5. Supported axially on the camshaft for use on the moon, the sliding cam 5 spans the lateral zone 17 of the sliding cam that projects laterally with respect to the sliding sleeve 15 when viewed in the axial direction. Axially moveable with respect to the bearing bushings used for the centering of the sliding cam 5 on the bearing bushings 8 of the camshaft bearings 2, 3 which are fixed so as not to move axially on the camshaft. do.

Description

VALVE TRAIN FOR COMBUSTION ENGINE AND METHOD FOR MANUFACTURING THEREOF

The present invention relates to a valve train for a multicylinder internal combustion engine and to a method of manufacturing such a valve train, according to the preamble of claim 1.

In recent internal combustion engines, variable valve trains are used to optimize the filling motion in the combustion chamber, whereby several valve strokes can be adjusted in the gas exchange valves of the internal combustion engine. From DE 196 11 641 C1 a valve train of an internal combustion engine is known which enables the operation of a gas exchange valve with several different strokes. In this connection a sliding cam having a plurality of cam tracks is mounted on the camshaft so as to be rotatable but axially movable. The sliding cam has a link section, in which an actuating element of a stud-shaped actuator is engaged to realize the axial movement of the sliding cam in the link section. The axial movement of the sliding cams regulates different valve strokes at the individual gas exchange valves. According to DE 196 11 641 C1 the sliding cam can be engaged by the locking device after axial movement with respect to the camshaft.

A valve train for an internal combustion engine having a sliding cam that can move axially on a camshaft is also known from DE 10 2007 027 979 A1. According to the prior art, the sliding cam has an inner gear, the inner gear interacting with the outer gear of the camshaft to support the sliding cam on the camshaft, thereby allowing the camshaft to move on the one hand despite the possibility of axial movement of the sliding cam relative to the camshaft. Centering of the sliding cam on and on the other hand torque transmission from the camshaft to the sliding cam is ensured.

Therefore, the centering function and the torque transmission function are in charge of one identical inner gear of the sliding cam and the outer gear of the camshaft according to the prior art. Bearings of this type that perform both centering and torque transfer functions are very sensitive to tolerances and are very complex to manufacture.

The object of the present invention is to improve the valve train according to the preamble of claim 1 so that it is less sensitive to tolerances and can be manufactured more simply. It should also provide a simple way to make such a valve train.

The problem is solved by a valve train having the features of claim 1 according to the present invention. According to the invention, the individual sliding cams are arranged between the individual camshafts and the individual sliding cams in the radial direction and through the sliding sleeves axially movable on the individual camshafts and in the axial direction. In the intermediate zone of the respective sliding sleeves fixedly connected with the sliding cams are axially movable on the respective camshafts so as to be used for torque transmission to the respective sliding cams, wherein the respective sliding cams Used for centering individual sliding cams on bearing bushings of camshaft bearings, which are fixed so as not to move axially on the camshaft, over the lateral section of the sliding cam projecting laterally with respect to the respective sliding sleeve in a direction. It is axially movable relative to the bearing bushings.

In the valve train according to the present invention, the centering function of the individual sliding cams and the torque transmission function to the individual sliding cams are not merely separated functionally and spatially, but rather various component combinations are involved in the functions. That is, the camshaft, the sliding sleeve and the sliding cam are involved in the torque transmission function, and the camshaft, the bearing bushing and the sliding cam are involved in the centering function. This allows for the custom design of individual related parts, allowing for reduced tolerance sensitivity and simple manufacture of valve trains.

Preferably, the bearing bushing and the sliding sleeves each have a plurality of flat portions on their outer periphery, the periphery of the flat portions defining the support shoulders, the flat portions of the bearing bushing flatten the sliding sleeves when viewed in the peripheral direction. Offset relative to the parts. This supports the simple manufacture or assembly of the valve train.

A method of manufacturing such a valve train is defined in claim 9, comprising at least a) providing at least one camshaft with an outer gear, b) at least one sliding sleeve with a bearing bushing for the camshaft bearing with an inner gear and an inner gear. C) providing one or more sliding cams, d) arranging and securing the bearing bushings on the individual camshafts, and then arranging the sliding sleeves on the individual camshafts, and then placing additional bearing bushings on the individual camshafts. Positioning and securing onto the bearing (this step is repeated until all the sliding sleeves and bearing bushings are arranged on the individual camshafts), e) the bearing bushings arranged on the individual camshafts and the arrangement on the individual camshafts Or finishing each sliding sleeve to the final dimension in the absence of deviation of concentric motion, f) said or each Step of forming through the groove, in particular the longitudinal direction and preferably the material accumulating groove to the outer surface of the sliding sleeve; g) positioning and securing the respective sliding cams on the respective sliding sleeves.

In the following description further features and feature combinations are described. Specific embodiments of the present invention are shown simplified in the drawings and will be described more clearly in the following detailed description.

1 is a schematic cross-sectional view of a valve train of an internal combustion engine.
FIG. 2 is a detailed view of a partially manufactured state of the valve train of FIG. 1.
3 is a cross-sectional view of the valve train of FIG. 2 taken along cut line AA.
4 is a cross-sectional view of the valve train of FIG. 2 taken along cut line BB.

1 shows a cross-sectional view of an internal combustion engine in the camshaft 1 region of the valve train of the internal combustion engine. The camshaft 1 shown in FIG. 1 is supported by camshaft bearings 2, 3 in a cylinder head of an internal combustion engine, not shown, which preferably consists of a cylinder head lower part and a camshaft case. The lower cylinder head and the camshaft case may be integrally formed.

The camshaft 1 shown in FIG. 1 is implemented as an intake camshaft and serves to control the intake valves 4 of the internal combustion engine with the help of a cam follower, not shown. An unshown exhaust camshaft is provided for controlling the unshown exhaust valves of the internal combustion engine. Intake valves and exhaust valves are gas exchange valves of an internal combustion engine.

Per cylinder preferably two intake valves 4 and two unshown exhaust valves are provided, the intake valves 4 of the intake camshaft 1 being controlled and operated in a known manner. The exhaust valves are controlled and operated in a known manner by an exhaust camshaft, not shown. In addition, the intake camshaft 1 and the exhaust camshaft (not shown) each have a plurality of sliding cams 5.

For the support of the intake camshaft 1 as seen in FIG. 1, camshaft bearings 2, 3, which are already mentioned, are provided, which are configured as radial bearing devices, which camshaft bearings comprise a lower bearing ring body 6, The lower bearing ring body may be integrally formed with the camshaft case 4. In addition, all the camshaft bearings 2, 3 are for example individual bearing caps 7 fixed to the lower bearing ring body 6 with the aid of screws and bearing bushings 8 attached on the intake camshaft 1. It includes. The bearing cap 7 can be connected with the bearing bridge.

According to FIG. 1 the sliding cam 5 consists of a centrally located link zone 9 and two outer cam zones 10. The individual outer cam zone 10 comprises three cam tracks 11, where different valve strokes are adjusted by each of the cam tracks 11. The sliding cam 5 shown in FIG. 1 thus comprises an axially movable cam section 10 with three cam tracks 11 for each valve. There may be a plurality of link zones on the lateral outward side of the cam zone 10. An actuator 12 comprising studs 13 is assigned to every sliding cam 5, which studs 13 are provided with grooves 14 of the sliding cam 5 formed on the outer surface of the link section 9. Interact As a result, the axial movement of the sliding cam 5 takes place in the region between the two cam bearings 2, 3.

By means of the axial movement of the sliding cam 5, the individual gas exchange valves are specifically operated in the predetermined cam track 11, so that different valve lift adjustments are made. The interaction of the studs 13 of the actuator 12 with the grooves 14 of the link zone 9 is familiar to those skilled in the art.

In order to ensure proper functioning of the valve train, on the one hand the individual sliding cams 5 have to be centered with respect to the camshaft 1 and on the other hand the torque transmission from the camshaft 1 to the individual sliding cams 5 Should be guaranteed.

In order to provide a torque transmission function from the camshaft 1 to the sliding cam 5, the sliding cam 5 shown in FIG. 1 has a sliding sleeve 15 supported movably in the axial direction on the camshaft 1. It is supported to be movable in the axial direction on the cam shaft 1 shown through.

The sliding sleeve 15 is arranged between the camshaft 1 and the sliding cam 5 when viewed in a radial direction, in which the sliding sleeve 15 is torsionally rotated with the sliding cam in the intermediate region 16 of the sliding cam 5. So that it is not connected. The torque transmission from the camshaft 1 to the sliding cam 5 therefore takes place on the sliding sleeve 15 starting from the camshaft 1 and finally through the sliding sleeve 15 onto the sliding cam 5.

Centering on the camshaft 1 of the sliding cam 5 is provided through a bearing bushing 8 fixedly immovably axially on the camshaft 1, where the sliding cam 5 shown in FIG. Camshaft bearings 2, 3, which are fixed such that they cannot be moved axially on the camshaft 1, through the lateral section 17 of the sliding cam that projects laterally with respect to the sliding sleeve 15 when viewed in the axial direction. Axially movable relative to the bearing bushings 8 in the zones of the bearing bushings 8.

The centering of the sliding cam 5 on the camshaft 1 is therefore made through bearing bushings 8 fixedly immovably on the camshaft 1, with the sliding cam 5 against the bearing bushings. May move axially through the sliding sleeve 15.

Therefore, the torque transmission function and the centering function of the individual sliding cam 5 are not only functionally and spatially separated, but rather the functions are provided by various component combinations.

The torque transmission function is arranged on the camshaft 1, on the camshaft 1, a sliding sleeve 15 arranged axially movable and not rotated, and fixed on the sliding sleeve 15 axially so as not to rotate. Provided by the sliding cam 5.

The centering function includes a camshaft 1, bearing bushes 8 arranged axially fixed on the camshaft 1 so as not to rotate, and a sliding cam 5 axially movable with respect to the bearing bushings 8. Is provided by

The camshaft 1 has an outer gear 18 which interacts with the inner gear 19 of the sliding sleeve 15, in which case the gears 18, 19 are engaged with each other so that the sliding sleeve on the camshaft 1 ( Axial movement of the 15 and prevention of torsional rotation of the sliding sleeve 15 with respect to the camshaft 1, as well as axial movement of the sliding cam 5 on the camshaft and the sliding sleeve 15 from the camshaft 1 Torque transmission on the sliding cam 5.

The bearing bushings 8 are forcibly engaged with the camshaft 1, in particular by being pressed onto the camshaft 1, in which the bearing bushings 8, on the one hand, engage with the camshaft such that it cannot move axially with respect to the camshaft 1. On the other hand, it is coupled with the camshaft such that there is no rotation or torsional rotation in the circumferential direction with respect to the camshaft 1. The individual sliding cams 5 are bearing bushings 8 on the bearing bushings 8 of the camshaft bearings 2, 3 over an area 17 protruding laterally with respect to the respective sliding sleeve 15 in axial direction. Axially movable relative to

The bearing bushings 8 and the sliding sleeve 15 have a plurality of flats 20 or 21 on their outer peripheries, respectively, the periphery of which defines the support shoulders 22 or 23.

Thus, as can be seen in FIG. 3, three flat portions 20 are each distributed over the outer periphery of the sliding sleeves 15, which are three supports distributed over the periphery of the individual sliding sleeve 15. Each of the shoulders 22 is defined. As can be seen in FIG. 4, in a similar manner, three flat portions 21 are distributed over the outer periphery of the individual sliding sleeve 15, which define three support shoulders 23 to one another.

As the flat parts 20 of the bearings 8 are located opposite the flat parts 21 of the sliding sleeve 15, the support shoulders 22 of the bearing bushings 8 slide in the peripheral direction. It is offset from each other with respect to the support shoulders 23 of the sleeve 15. That is, when viewed by the axial projection method (see FIG. 4), the support shoulders 22 of the bearing bushings 8 are aligned with the flat portions 21 of the sliding sleeve 15, and the support shoulders of the sliding sleeve 15. 23 is aligned with the flat portions 20 of the bearing bushings 8.

The outer radius of the support shoulders 22 of the bearing bushings 8 corresponds to the outer radius of the support shoulders 23 of the sliding sleeve 15 and the inner radius of the sliding cam 5.

The sliding cam 5 is in particular a sliding and formally coupled sliding sleeve by forming grooves in the support shoulders 23 of the sliding sleeve and then squeezing the sliding cam 5 onto the sliding sleeve 15. Connected with (15). That is, the sliding cam may not be moved axially with respect to the sliding sleeve or may be rotated in the peripheral direction with respect to the sliding sleeve.

As already mentioned, the actuator 12 interacts with the sliding cam 5 for the axial movement of the sliding cam 5 shown in FIG. 1 on the camshaft 1. That is, one of the studs 13 interacts with one of the grooves 14 of the link zone 9 of the sliding cam 5, with the substantial axial direction of the sliding cam 5 on the camshaft 1. Movement is provided through the sliding sleeve 15. After axial movement of the sliding sleeve on the camshaft 1, the sliding sleeve 15 is fixed in an axial relative position on the camshaft 1, thereby sliding the sliding cam 5 to the intake valve 4 to be operated. The valve train uses a locking device 24 to fix it in an axial relative position (see in particular FIG. 2).

The locking device 24 is received between the camshaft 1 and the sliding sleeve 15 in the cross hole 25 of the camshaft 1 and by the latching balls 27 pressed by one or more spring elements 26. In interaction with the latching grooves 28 formed in the inner surface of the sleeve 15, the latching balls 27 of the camshaft 1 act to engage one of the latching grooves 28 of the sliding sleeve 15. 1 and 2 two latching balls 27 are shown. Only one such latching ball may be used per sliding sleeve.

For the manufacture of the valve train shown in various forms in FIGS. 1 to 4, first the outer gear 18 is provided on the camshaft 1, the inner gear on the bearing bushings 8 is likewise provided, and the sliding sleeves 15 is preceded by a process in which the inner gear and the sliding cam 5 are provided.

Then, a first bearing bushing 8, which simultaneously provides a so-called camshaft head 29, is disposed on the camshaft 1, and is connected to the camshaft 1 by force by compression.

The sliding sleeve 15 is then slid onto the outer gear 18 of the camshaft 1 with the inner gear 19 to engage the relative axial position on the camshaft 1 via the associated locking device 24.

Subsequently, another bearing bushing 8 is arranged on the camshaft 1 and is fixed on the camshaft 1 by force by compression.

This alternating arrangement of the sliding sleeve 15 and the bearing bushings 8 on the camshaft 1 until all the bearing bushings 8 and the sliding sleeves 15 are arranged on the individual camshaft 1 are arranged. Is repeated.

The bearing bushings 8 and the individual sliding sleeves 15 are spaced apart from each other in the axial direction of the camshaft 1 (see in particular FIG. 1), ie the individual sliding sleeves 15 and the respective sliding sleeves together. The sliding cam 5 supported on the 15 can be moved in the axial direction of the camshaft 1.

The camshaft 1 thus preassembled with the bearing bushing 8 and the sliding sleeve 15 is then finished to the final dimension in the area of the outer peripheral surfaces of the bearing bushing 8 and the sliding sleeve 15, for example by grinding. do. In this case, the deviation of the concentric movement in the region of the bearing bushing 8 and the sliding sleeve 15 is eliminated.

Grooves are then formed in the region of the sliding sleeve 15, ie in the region of the support shoulder 23 of the sliding sleeve, preferably by rolling, resulting in the accumulation of material in the region of the support shoulder 23. do.

Then, the sliding cam 5 is installed on the individual sliding sleeve 15 through axial sliding and pressed together with the sliding sleeve, wherein the material of the sliding sleeve 15 accumulated during rolling or forming grooves is obtained. Is embedded in the sliding cam 5 to form a force-coupled and shape-coupled connection between the two members.

As material accumulates in the area of the radially inner surfaces of the sliding sleeve 15 when the sliding cam 5 is axially slid onto the grooved sliding sleeve 15, the area of the bearing bushing 8 is flat. Parts 20 are formed.

The assembly takes place from the axial side, so that only the axial side of all the sliding cams 5 the area of the bearing bushing 8 region which is axially movably engaged with the individual side sections 17 of the sliding cam 5. Flat portions 20 should be provided. On the side facing the sliding cam 5, in the region of the bearing bushing 8, in which the sliding cam 5 is respectively engaged to move axially through the region 17 in relation to the respective sliding cam 5. The flat parts 20 may be omitted.

When the bearing bushing 8 and the sliding sleeve 15 arranged on the preassembled camshaft 1 are processed to the final dimensions, the processing of the flat portions 20, 21 and the support shoulders 22, 23 is also performed.

After assembly or manufacture is finished, the sliding cam 5 is fixedly connected to the sliding sleeve 15 and is supported on the bearing bushing 8 so that the deviation of concentric movement can be minimized and slid.

The sliding cam 5 can move axially with respect to the camshaft 1 and the bearing bushing 8 on the camshaft 1 via the sliding sleeve 15. The sliding cam 5 can be accurately positioned at each distal position on the bearing bushing 8 by a stopper, not shown, of the sliding sleeve 15.

The valve train according to the present invention enables precise centering and torque transmission to the sliding cam 5. Since various component combinations are involved in providing the centering and torque transfer functions, the individual components can be individually designed to meet the needs, resulting in a lower tolerance sensitivity of the valve train. In addition, simple manufacture of the valve train is ensured.

1: camshaft
2: camshaft bearing
3: camshaft bearing
4: intake valve
5: sliding cam
6: bearing ring body
7: bearing cap
8: bearing bushing
9: link zone
10: cam zone
11: cam track
12: actuator
13: stud
14: Groove
15: sliding sleeve
16: zone
17: zone
18: outer gear
19: inner gear
20: flat part
21: flat part
22: support shoulder
23: support shoulder
24: locking device
25: cross hole
26: spring element
27: latching ball
28: latching groove
29: camshaft head

Claims (10)

Valve train for multi-cylinder internal combustion engines,
One or more sliding cams axially movable on the respective camshaft 1 to one or more camshafts 1 rotatably supported in the one or more camshaft bearings 2, 3 for operation of the gas exchange valve of the internal combustion engine. (5) is provided, the individual sliding cams (5), on the one hand, despite the possibility of axial movement with respect to the individual camshafts (1) of the individual sliding cams (5). In the valve train for a multi-cylinder internal combustion engine, which is supported so as to ensure centering and torque transmission to the individual sliding cams 5 on the other hand,
a) Each sliding cam 5 is connected between the individual camshaft 1 and the individual sliding cams 5 in a radial direction through a sliding sleeve 15 which is axially movable on the respective camshaft 1. In the middle section 16 of the respective sliding cam 5 and fixedly connected with the sliding cam in the axial direction so that the respective sliding sleeve 15 is used for torque transmission to the respective sliding cam 5. Is supported on the individual camshaft (1) movably in the axial direction,
b) The individual sliding cams 5 move axially on the camshaft 1 over the lateral zone 17 of the sliding cam that projects laterally with respect to the individual sliding sleeve 15 when viewed in the axial direction. Characterized by being axially movably supported with respect to the bearing bushings 8 used for the centering of the individual sliding cam 5 on the bearing bushings 8 of the camshaft bearings 2, 3 which are fixed indefinitely. A valve train for a multicylinder internal combustion engine. 2. The camshaft (1) according to claim 1, wherein the camshaft (1) has an outer gear (18) and the individual sliding sleeves (15) have an inner gear (19), and the gears (18, 19) engaged with each other have a camshaft (1). Allow the individual sliding sleeve 15 and the individual sliding cams 5 to be moved in the axial direction, from the individual camshafts 1 through the individual sliding sleeves 15 5) A valve train for a multicylinder internal combustion engine, characterized in that torque can be transmitted. The valve for a multicylinder internal combustion engine according to claim 1 or 2, characterized in that the bearing bushings (8) are forcibly connected to the respective camshaft (1) by being compressed together with the respective camshaft (1). Train. 3. The sliding element (15) according to claim 1 or 2, wherein the respective sliding sleeve (15) is moved axially on the respective camshaft (1) and then at the axial relative position on the individual camshaft (1) by the locking device (24). A valve train for a multi-cylinder internal combustion engine, which can be fixed, whereby the individual sliding cams 5 can be fixed in an axial relative position with respect to the gas exchange valve to be operated. The latching ball 27 of the spring loaded locking device is accommodated in the holes 25 of the individual camshafts, and the individual sliding sleeves for securing the individual sliding sleeves 15 on the individual camshafts. A valve train for a multicylinder internal combustion engine, characterized by engaging the latching groove 28 of the sleeve. The bearing bushing 8 and the sliding sleeves 15 have a plurality of flat parts 20 and 21 on their outer peripheries, respectively, with the periphery of the flat parts supporting shoulders. (22, 23), characterized in that the flat portions 20 of the bearing bushing 8 are offset with respect to the flat portions 21 of the sliding sleeves 15 when viewed in the peripheral direction. Valve train for internal combustion engines. The outer radius of the supporting shoulders 22 of the bearing bushings 8 is the outer radius of the supporting shoulders 23 of the individual sliding sleeves 15 and the inner radius of the individual sliding cams 5. A valve train for a multicylinder internal combustion engine, characterized in that corresponding to the radius. 7. The sliding element 5 according to claim 6, wherein the respective sliding cams 5 are formed with grooves in the supporting shoulders 23 of the respective sliding sleeves 15 and the respective sliding cams 5 on the respective sliding sleeves 15. The valve train for a multi-cylinder internal combustion engine, characterized in that it is connected to the individual sliding sleeve (15) by force and formally coupled. A method of manufacturing a valve train according to claim 1,
a) providing at least one camshaft having an outer gear,
b) providing a bearing bushing for the camshaft bearing with the inner gear and at least one sliding sleeve with the inner gear;
c) providing one or more sliding cams;
d) arranging and securing the bearing bushings on the individual camshafts, and then arranging the sliding sleeves on the individual camshafts, and then placing and fixing the additional bearing bushings on the individual camshafts (this step comprises all sliding sleeves and bearings). Repeated until bushings are arranged on individual camshafts),
e) finishing the bearing bushings arranged on the individual camshafts and said or each sliding sleeves arranged on the individual camshafts to their final dimensions in the absence of deviations from concentric motion;
f) forming a groove in the outer surface of said or each sliding sleeve,
g) positioning and securing the respective sliding cams on the respective sliding sleeves. 10. The method of claim 9, wherein a plurality of flat portions are respectively machined at their outer peripheries when finishing the final dimensions of the bearing bushings arranged on the individual camshafts and the or respective sliding sleeves arranged on the individual camshafts. The outer periphery of the flat portions define a support shoulder.

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