JPH0614403U - Valve timing control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] In a valve timing controller that variably controls the opening / closing timing of the intake / exhaust valves of an internal combustion engine in accordance with the operating conditions, the rigidity and strength of the fixing bolt in the twisting and bending directions Prevent decline. A relative rotation between a driven sprocket 21 and a cam shaft 22 is converted by axial movement of a cylindrical gear 28. The tubular gear 28 is attached to the first and second pressure receiving chambers 3
First hydraulic circuit 37 for moving in one direction via 5, 36
Is formed by the axial hole 45 and the pair of radial holes 46 and 47 in the fixing bolt 25. The first and second radial holes 46 and 47 are formed at positions displaced by a certain distance in the axial direction of the shaft portion 25a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a valve timing control device that variably controls the opening / closing timing of intake / exhaust valves of an internal combustion engine according to operating conditions.

[0002]

[Prior art]

 Various conventional valve timing control devices have been provided, and an example thereof is the one described in Japanese Utility Model Application Laid-Open No. 3-110106 filed by the present applicant earlier.

As shown in FIG. 4, this valve timing control device has a cylindrical sprocket 1 to which a driving force is transmitted from a crankshaft of an engine, and a rotational force of the sprocket 1 opens and closes an intake valve, for example. A camshaft 2 integrally having a driving cam to be operated, a sleeve 4 fixed to one end 2a of the camshaft 2 via a fixing bolt 3, and a sleeve 4 and the sprocket 1, A cylindrical gear 5 for converting the relative rotational phase of the sprocket 1 and the camshaft 2 along with the movement in the axial direction, and a drive mechanism 6 for moving the cylindrical gear 5 in the left and right axial directions. The drive mechanism 6 relatively introduces hydraulic pressure into the pressure chamber 7 provided on the front end side of the tubular gear 5 and the first and second pressure receiving chambers 7a and 7b of the pressure chamber 7 separated by the movable member 8. And a compression spring 10 elastically mounted at the rear end of the tubular gear 5. In addition, the hydraulic circuit 9 is provided with a three-way solenoid valve 11 on the upstream side, and a hydraulic pressure composed of a spool valve 12a sliding in the valve hole 3a of the fixing bolt 3 and an electromagnetic actuator 12b on the downstream side. A switching mechanism 12 is provided.

When the engine is under a low load, the controller 13 outputs an OFF signal (non-energized) to the solenoid valve 11 and the solenoid actuator 12b to close the oil supply passage 9a. Therefore, the pressure oil pumped from the oil pump 14 is discharged from the drain passage 15 and is not supplied to the first pressure receiving chamber 7a, and the tubular gear 5 is moved to the leftmost by the spring force of the compression spring 10. , The phase of relative rotation between the sprocket 1 and the camshaft 2 is converted to one side.

On the other hand, when shifting from the low load region to the medium load region, an ON signal (energization) is output to the solenoid valve 11, and the pressure oil from the oil pump 14 passes through the communication passage 9b and the first oil passage 9c. It is introduced into the first pressure receiving chamber 7a. Accordingly, the movable member 8 moves rightward in the drawing until it abuts on the stopper portion 16, and moves the tubular gear 5 rightward by a predetermined amount. Therefore, the sprocket 1 and the camshaft 2 are moved to the other side. Relative rotation by a predetermined amount.

Further, when the load shifts to the high load range, an ON signal is also output to the electromagnetic actuator 12b, and the drive rod 12c presses the spool valve 12a against the spring pressure of the coil spring 12d, so that the spool valve 12a is pressed. The communication passage 6b and the second oil passage portion 9d are communicated with each other by 12a, while the drain hole 6e is communicated with the outside. For this reason, the hydraulic pressure in the first pressure receiving chamber 7a is discharged to the outside, and the pressure oil is introduced into the second pressure receiving chamber 7b to move the movable member 8 leftward to the maximum, and at the same time, the cylindrical gear Move 5 further to the right. As a result, the sprocket 1 and the camshaft 2 relatively rotate relatively to the other side.

Therefore, the sprocket 1 and the cam shaft 2 can be stably held not only in the two-stage relative rotational conversion in forward and reverse but also in an arbitrary intermediate relative rotational phase.

[0008]

[Problems to be solved by the device]

 However, in the above-mentioned conventional valve timing control device, the first oil passage portion 9c and the second oil passage portion 9d and the drain hole 9e, which properly communicate with the communication passage 9b in the spool valve 12a, are provided in FIG. As shown, they are formed so as to penetrate through the large-diameter shaft portion 3b of the fixing bolt 3 along the diameter direction. Therefore, the cross-sectional area of the portion of the fixing bolt 3 where the first and second oil passage portions 9c and 9d and the drain hole 9e are formed becomes small, and the rigidity and strength of the fixing bolt 3 in the twisting and bending directions are reduced. Is reduced. As a result, the size of the fixing bolt 3 needs to be increased, which may increase the size of the entire apparatus.

[0009]

[Means for Solving the Problems]

 The present invention has been devised in view of the above-mentioned conventional circumstances, and is characterized in that, in particular, the radial holes formed in the fixing bolt are formed at positions axially offset from each other.

[0010]

[Action]

 According to the present invention having the above-mentioned structure, by forming the radial holes at positions offset from each other in the axial direction, the cross-sectional area in which the radial holes are located is different from the conventional case of the diametrical holes. Grows. As a result, the rigidity of the fixing bolt is improved.

[0011]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Incidentally, this embodiment also shows the one applied to the intake valve side.

FIG. 1 shows an embodiment of a valve timing control device according to the present invention, in which 21 is a driven sprocket, which is a rotary body to which a driving force is transmitted from a crankshaft (not shown) by a timing chain, and 22 is one end 22a. A camshaft that is rotatably supported by a cam bearing 23 of a cylinder head and that opens and closes an intake valve (not shown) by the rotational force transmitted from a driven sprocket 21. One end 22a of this camshaft 22 is A sleeve 24, which is inserted in the inner axial direction of the driven sprocket 21, is fixed in the axial direction by a fixing bolt 25. In this sleeve 24, a tubular portion 24a on the rear end side is fitted to the camshaft one end portion 22a, and outer teeth 24b are formed at a substantially central position on the outer peripheral surface.

The driven sprocket 21 is fixed by caulking to a gear 21b integrally provided on the outer periphery of the rear end portion of the tubular body 21a and the inner peripheral surface where the gear 21b is located, by caulking the inner peripheral surface. An annular member 26 slidably supported on the outer peripheral surface of the one end portion 22a, and a disc-shaped member 26 that is fixed to the front end edge of the sleeve 24 together with a fixing bolt 25 to close the front end opening of the cylindrical main body 21a. It is composed of a front cover 27. Further, inner teeth 21c are formed substantially in the center of the inner peripheral surface of the cylindrical main body 21a. Further, the front end portion of the tubular main body 21a is slidably supported on the outer peripheral surface 27a of the front cover 27.

Further, between the sleeve 24 and the cylindrical main body 21a, a cylindrical gear 28 is arranged which is a phase conversion means that moves in the axial direction via a drive mechanism described later. The cylindrical gear 28 is composed of two gear components 29 and 30 formed by cutting and dividing a long gear in the direction perpendicular to the axis, and both gear components 29 and 30 each have a substantially vertical section. It has a V shape and is elastically connected in a direction in which they approach each other by a spring 31 and a connecting pin 32 mounted in the rear gear component 30. Further, the inner and outer circumferences of the respective gear components 29 and 30 are respectively formed with internal teeth and external teeth of helical teeth, and the inner teeth and the outer teeth of the cylindrical main body 21a and the sleeve 24 are formed on these inner and outer teeth, respectively. The outer teeth 24b of the above are meshed in a spiral manner. Further, the tubular gear 28 can be moved in the maximum forward direction (the position in FIG. 1) at the position where the front end edge of the front gear component 29 abuts the inner surface of the front cover 27 via the movable member 34 described later. On the other hand, the maximum rearward movement (rightward in the figure) is regulated at the position where the rear end edge of the rear gear component 30 abuts the inner surface of the annular member 26.

The drive mechanism includes a pressure chamber 33 formed between the front gear component 29 and the front cover 27, and a substantially annular movable body provided slidably in the axial direction of the pressure chamber 33. The member 34, the first annular pressure receiving chamber 35 on the front end side of the pressure chamber 33 separated by the movable member 34, the second thin annular pressure receiving chamber 36 on the rear side, and the pressure receiving chambers 35, 36. It is elastically mounted between the first and second hydraulic circuits 37 and 38 for supplying and discharging hydraulic pressure to and from the rear gear component 30 and the annular member 26, and the cylindrical gear 28 is attached in the forward direction. And a compression spring 39 for urging.

In the movable member 34, the inner peripheral surface 34 a is in contact with the front end face of the front gear component 29, and the maximum rightward moving position due to the pressure increase in the first pressure receiving chamber 35 is a cylindrical book. It is regulated by step portions 40 and 41 provided so as to face the inner peripheral surface of the body 21a and the outer peripheral surface of the sleeve 24. The step portions 40 and 41 are set so that the forming position is substantially the middle position of the maximum lateral movement position of the tubular gear 28.

The first hydraulic circuit 37 is formed in the cylinder head and the cam bearing 23 and in the radial direction of the cam shaft 22, and has one end communicating with the oil pump 43 through the oil main gallery 42. An axial hole 45 formed in the central axis direction of the shaft portion 25a of the fixing bolt 25 and communicating with the first oil passage 44, and a pair of radial holes branching from the end portion side of the axial hole 45. The first and second radial holes 46, 47, the annular groove 48 formed on the inner peripheral surface of the front end portion of the bolt insertion hole 24a of the sleeve 24, and communicating with the radial holes 46, 47, and the front cover 27. The inner end surface is formed with an annular groove 48 at one end and an annular groove 49 at the other end communicating with the first pressure receiving chamber 35.

As shown in FIGS. 1 to 3, the first and second radial holes 46 and 47 are formed at positions offset from each other with a certain distance in the axial direction of the shaft portion 25a. , At an angular position of 90 ° in the circumferential direction.

On the other hand, the second hydraulic circuit 38 is provided substantially parallel to the first oil passage 44, and one end of the second hydraulic circuit 38 communicates with the oil main gallery 42. An annular passage 51 formed between the outer peripheral surface of the shaft portion 25a of the fixing bolt 25 and the camshaft one end portion 22a and the inner peripheral surface of the bolt hole of the sleeve 24, and communicating with the second oil passage 50, and the sleeve 24. And a communication passage 52 which is formed in the diametrical direction and connects the annular passage 51 and the second pressure receiving chamber 36.

Further, in the middle of the first and second oil passages 44, 50, there are provided three-port two-position type switching solenoid valves 53, 54 which are switching valves, and the switching solenoid valves 53, 54 are provided. Is switched so that the upstream and downstream of the first and second oil passages 44 and 50 are communicated with each other, or the oil passages 44 and 50 and the drain passages 55 and 56 are communicated with each other, and a controller (not shown) including a microcomputer is used. It is designed to operate by switching. This controller detects the current engine operating state based on information signals from sensors and switches such as a crank angle sensor that detects the engine speed and an air flow meter that detects the amount of intake air, and controls it. A signal is output to each switching solenoid valve 53, 54.

The operation of this embodiment will be described below. That is, for example, when the engine load is low, an OFF signal is output to both switching solenoid valves 53 and 54 as shown in FIG. 1 to close the upstream sides of the first and second oil passages 44 and 50, and at the same time, to reduce the oil The drain passages 55, 56 are connected to the downstream side of the passages 44, 50. Therefore, the hydraulic oil pressure-fed from the oil pump 43 to the respective oil passages 44 and 50 and the hydraulic oil inside the first and second pressure receiving chambers 35 and 36 are discharged to the outside from the drain passages 55 and 56, respectively. The internal pressure of the chambers 35 and 36 decreases. Therefore, as shown in FIG. 1, the tubular gear 28 moves in the forward direction by the spring force of the compression spring 39, the front gear forming portion 29 abuts the front cover 27 via the movable member 34, and the maximum movement thereof. Held in position. Therefore, the driven sprocket 21 and the camshaft 22 are controlled to relatively rotate relatively to one side so as to delay the closing time of the intake valve.

On the other hand, when the engine operating state shifts from the low load region to the medium load region, for example, the second switching electromagnetic valve 54 maintains the OFF state, while the ON signal is output to the first switching solenoid valve 53. , The first oil passage 44 and the oil main gallery 42 are communicated with each other. Therefore, the hydraulic oil pumped from the oil pump 43 passes through the first oil passage 44, the axial hole 45, the first and second radial holes 46 and 47, the annular groove 48, and the annular groove 49 to the first oil passage. It is supplied into the pressure receiving chamber 34. Therefore, as the internal pressure of the first pressure receiving chamber 34 rises, the movable member 34 and the tubular gear 28 move rearward against the spring force of the compression spring 39, and the movable member 34 is moved to the stepped portions 40 and 41. The movement is restricted by hitting, and the tubular gear 28 is held at the intermediate position. Therefore, the driven sprocket 21 and the cam shaft 22 can optimally control the opening / closing timing of the intake valve in accordance with the relative rotational phase determined by the intermediate movement position of the tubular gear 28.

Further, when the engine shifts to the high load range, the ON signal is output to the second switching solenoid valve 54 while the first switching solenoid valve 53 continues to be in the ON state, and the drain passage 56 is closed. At the same time, the upstream and downstream of the second oil passage 50 are also communicated. Therefore, the hydraulic oil is supplied to both the first pressure receiving chamber 35 and the second pressure receiving chamber 36 through both the first and second hydraulic circuits 37 and 38, and therefore the internal pressure of the second pressure receiving chamber 36 is immediately increased. Then, the tubular gear 28 further rapidly moves to the rearward maximum speed until the rear gear forming portion 30 abuts on the annular member 26. Accordingly, the driven sprocket 21 and the cam shaft 22 are controlled to further rotate relatively to the other side so as to accelerate the closing timing of the intake valve.

As described above, in this embodiment, when the medium load range is shifted to the high load range, the hydraulic pressure is supplied from the both hydraulic circuits 37 and 38 to the pressure receiving chambers 35 and 36. Since the hydraulic oil in the first pressure receiving chamber 35 is kept at the maximum rightward movement position without returning to the direction, the working oil is centrally supplied to the second pressure receiving chamber 36. The internal pressure of 36 rapidly increases, and the movement responsiveness of the tubular gear 28 in the rearward direction is improved.

Further, since the first radial hole 46 and the second radial hole 47 are formed at positions offset in the axial direction of the shaft portion 25a, the respective radial holes 46 and 47 are located. The cross-sectional area of the fixing bolt 25 becomes larger than that of the conventional one formed in the diametrical direction, so that the fixing bolt 25 is prevented from being twisted, and the strength and rigidity in the bending direction are reduced. As a result, there is no risk of cracks, breakage, etc. occurring even when the tightening torque is relatively large during tightening and the device is operated for a long time after tightening. Moreover, since the radial holes 46 and 47 are also deviated in their circumferential positions, the deterioration of rigidity and strength is further prevented.

When the high load region is shifted to the medium load region, the OFF signal is output only to the second switching solenoid valve 54 as shown in FIG. 2, so that the hydraulic oil in the second pressure receiving chamber 36 becomes Since the second hydraulic pressure circuit 38 flows backward and is rapidly discharged from the drain passage 56 to the outside, the inside of the second pressure receiving chamber 36 is rapidly lowered, and the tubular gear 28 is quickly moved to the intermediate movement position. .

Further, when the load shifts to the low load range, an OFF signal is also output to the first switching solenoid valve 53, the internal pressure of the first pressure receiving chamber 35 rapidly decreases, and the tubular gear 28 moves to the maximum front. Move quickly in the direction.

Further, the present invention is not limited to the configuration of the above-described embodiment, and can be applied to phase conversion means other than the cylindrical gear 28.

[0029]

[Effect of device]

 As is clear from the above description, according to the present invention, the radial holes formed in the fixing bolt are formed at positions axially offset from each other, so that the cross-sectional area of the forming position is different from the conventional one. It is larger than the conventional one, and it is possible to prevent the rigidity and strength of the fixing bolt from decreasing. As a result, it is not necessary to increase the diameter of the fixing bolt, and the device does not increase in size. In addition, it is possible to prevent easy occurrence of cracks and breakage of the fixing bolt during or after tightening the fixing bolt.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a valve timing control device according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a cross-sectional view showing a conventional valve timing control device.

5 is a sectional view taken along line CC of FIG.

[Explanation of symbols]

 21 ... Followed sprocket (rotating body) 22 ... Cam shaft 22a ... One end 25 ... Fixing bolt 28 ... Cylindrical gear (phase conversion means) 33 ... Pressure chamber 37, 38 ... 1st, 2nd hydraulic circuit 45 ... Axial hole 46 ... 1st radial hole 47 ... 2nd radial hole

Claims (1)

[Scope of utility model registration request] 1. A rotary body driven by an engine, a cam shaft for opening and closing an intake / exhaust valve by a rotational force transmitted from the rotary body, and a cam body interposed between the rotary body and one end of the cam shaft. And a phase conversion means that operates by operating hydraulic pressure in a pressure chamber at one end side to convert the relative rotational phase of the both, an axial hole inside a fixing bolt screwed to one end of the camshaft, In a valve timing control device including a hydraulic circuit that supplies and discharges operating hydraulic pressure to and from the pressure chamber via a plurality of radial holes, the radial holes in the fixing bolt are formed at positions axially offset from each other. A valve timing control device for an internal combustion engine, characterized in that