Patent Application
20190003349
The present invention relates to an internal combustion engine valve timing control device for controlling opening and closing timings of an intake valve set and/or an exhaust valve set variably depending on a state of operation of an internal combustion engine.
A patent document 1 discloses a publicly known conventional internal combustion engine valve timing control device.
This valve timing control device includes: a housing including a housing body, a front plate, and a rear plate, wherein the housing body has a cylindrical tubular shape and includes a gear part (sprocket), and wherein the gear part is formed integrally with an outer peripheral surface of the housing body, and wherein a timing chain is wound around the gear part for crankshaft torque transmission, and wherein the front plate encloses a front end opening of the housing body, and wherein the rear plate encloses a rear end opening of the housing body; and a vane member mounted rotatably in the housing body, wherein the vane member is formed integrally with a plurality of vanes configured to define a plurality of retard hydraulic chambers and a plurality of advance hydraulic chambers in cooperation with a plurality of shoes formed to project from an inner peripheral surface of the housing body.
The vane member is fixed to an axial end portion of an intake-side camshaft by a cam bolt, and configured to control, via the camshaft, opening and closing timings of an intake valve set depending on a state of operation of an engine, by being rotated by working oil to a retard side or to an advance side with respect to the housing, wherein the working oil is selectively supplied from a hydraulic circuit to the retard hydraulic chambers and the advance hydraulic chambers and drained from the retard hydraulic chambers and the advance hydraulic chambers to the hydraulic circuit.
The configuration that the vane member and the housing are cantilevered by the end portion of the camshaft, may cause the housing to be inclined via the gear part of the sprocket when a load is applied to the gear part from the timing chain.
This tends to cause stress concentration continuously at a place where the gear part is connected to the housing body, namely, at a side of a root portion (proximal end portion) of the gear part facing the front plate, for example, by application of a moment at a part of the gear part around which the timing chain is wound, in a direction of inclination toward the front plate. This may adversely affect endurance of the housing body.
The present invention is made with attention to the technical problem about the conventional valve timing control device described above, and is targeted for providing a valve timing control device where endurance of a housing body can be enhanced by enhancement of rigidity of a proximal end portion of a gear part by a raised portion.
The present invention is characterized by comprising: a housing body having a cylindrical tubular shape, and including a plurality of shoes, wherein the shoes project from an inner peripheral side of the housing body; a plurality of gear parts, wherein each of the gear parts includes a proximal end portion formed integrally with an outer peripheral surface of the housing body, and wherein a transmission member is wound around the gear parts for crankshaft torque transmission; a vane member configured to be fixed to a first axial end portion of a camshaft, and mounted rotatably in the housing body, wherein the vane member includes a plurality of vanes, and wherein each of the vanes is configured to separate a space between corresponding adjacent two of the shoes into a retard hydraulic chamber and an advance hydraulic chamber; a rear plate enclosing a first axial end opening of the housing body, wherein the first axial end opening faces the camshaft; a front plate enclosing a second axial end opening of the housing body, wherein the second axial end opening is opposite to the first axial end opening, and farther from the camshaft than the first axial end opening; and a raised portion formed at least between the outer peripheral surface of the housing body and a first lateral surface of the proximal end portion of each of the gear parts, wherein the first lateral surface faces the front plate.
According to the present invention, the provision of the raised portion serves to enhance the rigidity of the proximal end portion of the gear part, and thereby enhance the endurance of the housing body.
The following describes internal combustion engine valve timing control devices according to embodiments of the present invention with reference to the drawings, wherein the present invention is applied to an intake valve side of a multi-cylinder internal combustion engine including two intake valves and two exhaust valves per cylinder.
As shown in
Sprocket 1 is formed integrally with a housing body 8 of a housing 5 described below of phase-varying mechanism 3, and is described below in detail in description of housing 5.
Camshaft 2 is rotatably supported via a cam bearing with respect to a cylinder head not shown, and includes a pair of drive cams not shown per cylinder for opening and closing two intake valves per cylinder, wherein each drive cam is fixed to an outer peripheral surface of camshaft 2 in a predetermined axial position, and has an identical profile. Camshaft 2 includes a bolt insertion hole 2b formed closer to a first end portion 2a, wherein bolt insertion hole 2b extends in an axial direction of camshaft 2, and wherein a shaft part 6a of a cam bolt 6 is inserted in bolt insertion hole 2b to extend in the axial direction and fix a vane member 7. Bolt insertion hole 2b includes a distal end portion including an internal thread 2c to which an external thread 6c is screwed, wherein external thread 6c is formed at a distal end portion of cam bolt 6.
As shown in
Housing 5 includes: housing body 8 formed of sintered metal to have a cylindrical tubular shape; a front plate 11 enclosing a front end opening of housing body 8 farther from camshaft 2; and a rear plate 12 enclosing a rear end opening of housing body 8 facing the rear plate 12.
Housing body 8 is integrally formed of sintered alloy to have a cylindrical tubular shape, and is formed integrally with sprocket 1 and four shoes 8c-8f, wherein sprocket 1 is located at a portion of an outer peripheral surface 8a of housing body 8 somewhat closer to rear plate 12 than a center in an axial direction of housing body 8, wherein shoes 8c-8f are formed at and project from an inner peripheral surface 8b of housing body 8, and substantially evenly spaced in a circumferential direction of housing body 8.
Sprocket 1, which is formed integrally with housing body 8, is formed integrally with a plurality of gear parts 1a around which the timing chain is wound.
These shoes 8c-8f and four vanes 16a-16d described below of vane member 7 separate the operation chamber into four retard hydraulic chambers 9 and four advance hydraulic chambers 10.
Housing body 8, front plate 11, and sprocket 1 are fixed to each other by four bolts 13, wherein each bolt 13 is inserted in a bolt insertion hole 8g formed in a corresponding one of shoes 8c-8f, wherein bolt insertion hole 8g extends through the corresponding shoe 8c-8f.
Housing body 8 includes two thinning portions 8h, 8i, wherein each thinning portion 8h, 8i is formed at a base portion of a corresponding one of first shoe 8c and second shoe 8d having a relatively large width. Each thinning portion 8h, 8i is formed to have an arc shape along the cylindrical shape of housing body 8, for reduction of weight of housing body 8 and overall weight balance of housing body 8 with different shapes of shoes 8c-8f.
The base portion of first shoe 8c of housing body 8 is formed with a positioning groove 8j for positioning with respect to rear plate 12 as described below, wherein positioning groove 8j extends through the base portion of first shoe 8c in the axial direction.
Front plate 11 is formed of carbon steel to have a disc-shape, and includes a relatively large through hole 11a at a central portion of front plate 11, wherein through hole 11a passes through the front plate 11. Front plate 11 further includes four bolt insertion holes 11b arranged at its outer peripheral part and substantially evenly spaced in the circumferential direction, wherein each bolt insertion hole 11b extends through the front plate 11, and wherein bolts 13 are inserted in bolt insertion holes 11b.
Front plate 11 includes an outer end surface 11c that is flat and is configured to be in contact with an inside edge of a spiral spring 33 described below. Namely, outer end surface 11c serves as a spring seat for spiral spring 33. Accordingly, in order to prevent a head part 13a of each bolt 13, which is screwed in bolt insertion hole 11b, from obstructing contact of spiral spring 33 with outer end surface 11c, a hole edge of bolt insertion hole 11b at the outer end surface 11c is provided with a countersunk portion 11d that has a thin groove shape where a root portion of a shaft part of each bolt 13.
As shown in
Hood part 14b is formed to have a diameter such that hood part 14b covers substantially entire part of an axial end surface of second engaging end portion 33c wound around the pin body 14a, to prevent the second engaging end portion 33c of spiral spring 33 from being released from outer end surface 11c of front plate 11.
Rear plate 12 includes four internally threaded holes 12a arranged at the outer peripheral part and substantially evenly spaced in the circumferential direction, wherein external thread portion 13c formed at the distal end portion of shaft part 13b of bolt 13 is inserted in a corresponding one of internally threaded holes 12a. The outer peripheral part of rear plate 12 includes a positioning hole 12b in which an end portion of positioning pin 36 is press-fitted, wherein positioning pin 36 is inserted and fitted in positioning groove 8j of housing body 8 in the axial direction, for positioning with respect to the housing body in the circumferential direction and the radial direction during assembling of components.
Vane member 7 is integrally formed of sintered metal material, and as shown in
A tubular projecting part 17 is formed integrally in a central portion of the front end surface of rotor 15 facing the front plate 11, and is arranged coaxially with rotor 15. As shown in
Tubular projecting part 17 has an inside diameter that is larger than the outside diameter of head part 6b of cam bolt 6 such that when the device is assembled, the head part 6b of cam bolt 6 is placed and accommodated inside the tubular projecting part 17.
The end surface of distal end portion 17a of tubular projecting part 17 is provided with an engaging groove 18 with which first engaging end portion 33b described below of spiral spring 33 is engaged.
As shown in
Rotor 15 includes a circular fitting recess 15b on its rear end surface, wherein first end portion 2a of camshaft 2 is fitted in fitting recess 15b, and wherein the rear end surface of rotor 15 is in sliding contact with the inner end surface of rear plate 12 facing the rotor 15, with a slight side clearance. On the other hand, the front end surface of rotor 15 is in sliding contact with the inner end surface of front plate 11 facing the rotor 15, with a slight side clearance.
As shown in
Each vane 16a-16d has end surfaces in the thickness direction (in the rotor axial direction) which are in sliding contact with the inner end surface of rear plate 12 and the inner end surface of front plate 11 with slight side clearances, and serves for similar sealing functioning at the inner end surface of front plate 11 and the inner end surface of rear plate 12.
Of vanes 16a-16d, the first vane 16a has a sector shape having the largest width and has the heaviest weight, while each of the second to fourth vanes 16b-16d except for first vane 16a has substantially the same width that is smaller than that of first vane 16a.
As shown in
On the other hand, lateral surfaces of the other second to fourth vanes 16b-16d are out of contact with the corresponding lateral surfaces of shoes 8c, 8d facing in the circumferential direction. This serves to enhance the precision of contact of first vane 16a with first shoe 8c and second shoe 8d, and further enhance the speed of oil pressure supply to retard hydraulic chambers 9 and advance hydraulic chambers 10, and thereby enhance the response of rotation of vane member 7 in normal and reverse directions.
Each retard hydraulic chamber 9 and each advance hydraulic chamber 10 are hydraulically connected to hydraulic circuit 4 via a first communication hole 9a and a second communication hole 10a respectively, wherein first communication hole 9a and second communication hole 10a are formed inside of rotor 15 and extend radially.
Hydraulic circuit 4 is configured to selectively supply and drain working oil (hydraulic pressure) to and from retard hydraulic chambers 9 and advance hydraulic chambers 10. As shown in
One end of each of retard oil passage 19 and advance oil passage 20 is connected to a passage port of electromagnetic switching valve 22, whereas the other end of each of retard oil passage 19 and advance oil passage 20 is hydraulically connected to first communication hole 9a or second communication hole 10a via the cylinder head not shown and a cylinder block not shown and via a retard passage section 19a or an advance passage section 20a, wherein retard passage section 19a is formed between the outer peripheral surface of shaft part 6a of cam bolt 6 and bolt insertion hole 2b, and wherein advance passage section 20a is formed inside of first end portion 2a of camshaft 2 and extends in the axial direction.
Retard passage section 19a communicates with retard hydraulic chambers 9 via first communication holes 9a, whereas advance passage section 20a communicates with advance hydraulic chambers 10 via second communication holes 10a.
As shown in
Oil pump 21 includes a suction passage 21b and drain passage 23 which communicate with an inside of an oil pan. A filter not shown is provided at a downstream side of discharge passage 21a of oil pump 21, wherein the downstream side is hydraulically connected to a main oil gallery M/G for supplying lubricating oil to sliding parts of the internal combustion engine. Oil pump 21 is further provided with a flow control valve not shown for controlling a flow rate of working oil suitably by draining an excessive quantity of working oil, which is discharged from discharge passage 21a, to the oil pan.
Electronic controller 24 includes an internal computer configured to: receive input of informational signals from various sensors not shown, such as a crank angle sensor, an airflow meter, an engine water temperature sensor, a throttle valve opening sensor, and a cam angle sensor for sensing the current rotational phase of camshaft 2; determine the current operating state of the engine; control the spool valve to travel to set positions, by outputting a control pulse current to a coil of electromagnetic switching valve 22; and thereby perform a switching control for the passages.
A lock mechanism 27 is provided between first vane 16a and rear plate 12 for locking the vane member 7 to the most advanced position with respect to housing 5.
As shown in
The most part of lock pin 29 including the distal end portion 29a is cylindrically shaped. Lock pin 29 is biased in the forward direction (in the direction for engagement) by a coil spring 31, wherein coil spring 31 is mounted in compressed state between an inner surface of front plate 11 and a bottom surface of a recess of lock pin 29, wherein the recess is formed to extend in the axial direction from the rear end side of lock pin 29. Lock pin 29 has an annular larger diameter portion at the outer periphery of the rear end part, wherein the larger diameter portion is in sliding contact with a larger diameter hole of slide hole 28. An annular first pressure receiving chamber 32a is formed at a gap between the larger diameter portion of lock pin 29 and the larger diameter hole of slide hole 28.
Lock hole 30 is formed larger than the outside diameter of the distal end portion of lock pin 29, and is located in a part of rear plate 12 closer to retard hydraulic chamber 9 in the circumferential direction, and is set such that with engagement of lock pin 29, the relative conversion angle of vane member 7 with respect to housing 5 is at the most retarded side. Lock hole 30 has an inner peripheral surface to which an anti-wear ring 30a is press-fitted and fixed. Ring 30a is formed by carburizing to have a high hardness, so that ring 30a can bear repeated engagement and release of lock pin 29 which accompanies sliding contact of the outer peripheral surface of lock pin 29 with the inner peripheral surface of lock hole 30.
The engaging-releasing mechanism includes: coil spring 31 configured to bias the lock pin 29 in the forward direction; first pressure receiving chamber 32a; a second pressure receiving chamber 32b formed at a bottom side of lock hole 30; a releasing hydraulic circuit configured to supply hydraulic pressure to pressure receiving chambers 32a, 32b, and thereby cause lock pin 29 to travel backward.
As shown in
As shown in
As shown in
Spiral spring 33 includes: a body 33a formed by winding a flat rectangular wire, which has a substantially rectangular cross-section, substantially in a plane, such that surfaces in the longitudinal direction face each other, the body 33a having a shape whose diameter gradually increases from its inside peripheral part to its outside peripheral part; first engaging end portion 33b formed to have a curved shape, by bending an innermost peripheral portion of body 33a inwardly in the radial direction; and second engaging end portion 33c curved to have a semicircular hook shape, by bending an outermost peripheral part of body 33a outwardly in the radial direction.
First engaging end portion 33b is engaged with and fixed to an arc-shaped surface 18a of engaging groove 18 of tubular projecting part 17 facing the first engaging end portion 33b, whereas second engaging end portion 33c is engaged with and fixed to an outer peripheral surface of hooded pin 14 provided at outer end surface 11c of front plate 11. This spiral spring 33 generates a spring force to constantly assist rotation of vane member 7 toward the advance side. Specifically, when vane member 7 rotates toward the retard side with respect to housing 5, spiral spring 33 is deformed with decreasing diameter, to bias the vane member 7 toward the advance side. This biasing force is not so large, but is comparable to a negative component of an alternating torque occurring in camshaft 2, wherein the negative component causes vane member 7 to move toward the retard side. Accordingly, when vane member 7 is released from locking of lock mechanism 27, combination of the biasing force of spiral spring 33 and the negative component of the alternating torque serves to place the vane member 7 in balance in an intermediate position between the most retarded position and the most advanced position.
The outer end surface 11c of front plate 11 is provided with a support pin 34 that assists the biasing function of spiral spring 33 by enhancing the torque occurring in spiral spring 33.
Support pin 34 is press-fitted and fixed to a place distant by a predetermined angle from hooded pin 14, and includes an outer peripheral surface in contact with an outermost peripheral part of spiral spring 33. This serves to enhance a torque occurring between second engaging end portion 33c and a portion of spiral spring 33 in contact with support pin 34, when spiral spring 33 is deformed with decreasing diameter.
The outer peripheral surface of tubular projecting part 17 includes an annular groove 35 configured to accommodate an innermost peripheral portion 33d of spiral spring 33. Annular groove 35 has a predetermined width greater than spring width W1 of spiral spring 33 such that spiral spring 33 can be engaged in annular groove 35.
Moreover, annular groove 35 has a depth less than thickness of spiral spring 33 such that when the innermost peripheral part of spiral spring 33 engages with annular groove 35, an outside of the innermost peripheral part of spiral spring 33 in the radial direction is constantly out of contact with annular groove 35 (namely, exposed out of annular groove 35).
Since spiral spring 33 has the shape whose diameter gradually increases from the inner peripheral side to the outer peripheral side, the part of spiral spring 33 close to first engaging end portion 33b is in contact with the bottom surface of annular groove 35, whereas spiral spring 33 gradually gets out of contact with the bottom surface of annular groove 35 as followed toward the outer peripheral side.
As shown in
Raised portion 40 is formed simultaneously with formation of housing body 8 by sintering. As shown in
Raised portion 40 includes an outer surface 40a that has a downward inclination from first lateral surface 1c of sprocket 1, namely, first lateral surface 1c of proximal end portion 1b of gear part 1a, toward the outer peripheral surface 8a of housing body 8, so that raised portion 40 has a tapering shape. The angle of inclination of outer surface 40a of raised portion 40 with respect to outer peripheral surface 8a is an acute angle. Raised portion 40 has a height H at first lateral surface 1c, wherein height H is set not to obstruct winding of timing chain 42.
As shown in
First, when an ignition switch is turned off for engine stop, a large negative component of the alternating torque of camshaft 2 presses the vane member 7 to the most retarded position against the spring force of spiral spring 33. Under this condition, the distal end portion 29a of lock pin 29 engages in lock hole 30, thereby restricting the relative rotational position of vane member 7 in the retard side suitable for engine start. This causes the opening and closing timings of the intake valve set to be held stably at the most retarded side.
When the ignition switch is turned on for engine start, electronic controller 24 maintains the coil of electromagnetic switching valve 22 de-energized. This allows communication between discharge passage 21a of oil pump 21 and retard oil passage 19, and simultaneously allows communication between advance oil passage 20 and drain passage 23.
As a result, the working oil discharged from oil pump 21 flows into each retard hydraulic chamber 9 via retard oil passage 19, to set the pressure in retard hydraulic chamber 9 high, while the working oil in each advance hydraulic chamber 10 is drained via advance oil passage 20 and drain passage 23 into the oil pan, to set the pressure in advance hydraulic chamber 10 low.
Under this condition, the working oil flowing into each retard hydraulic chamber 9 flows also through the releasing hydraulic circuit to pressure receiving chamber 32 and lock hole 30 to set their pressures high, thereby causing the lock pin 29 to travel backward, and causing the distal end portion 29a to get out of lock hole 30, and ensuring free rotation of vane member 7.
Accordingly, as shown in
This serves to allow smooth cranking and preferable startability when the engine is started by turning on the ignition switch.
In this state, the relative rotation of vane member 7 to the retard side with respect to housing 5 causes the spiral spring 33 to be deformed with decreasing diameter.
When the engine enters a low speed and low load region after engine start, electronic controller 24 outputs a control current to electromagnetic switching valve 22, to allow communication between discharge passage 21a and advance oil passage 20, and communication between retard oil passage 19 and drain passage 23 simultaneously. This causes the working oil in retard hydraulic chambers 9 to be drained to depressurize retard hydraulic chambers 9, and causes the working oil to be supplied to advance hydraulic chambers 10 to pressurize advance hydraulic chambers 10. Since hydraulic pressure is supplied from advance hydraulic chambers 10 via the releasing hydraulic circuit to pressure receiving chamber 32 under this condition, the supplied hydraulic pressure serves to maintain the lock pin 29 out of lock hole 30.
As a result, vane member 7 is caused to rotate in the clockwise direction in
In this way, the relative rotational phase of camshaft 2 with respect to housing 5 is changed to the most advanced side. This serves to control the opening and closing timings of the intake valve set, and thereby enhance the output of the engine under the low speed and low load condition. This effect can be obtained also in a high speed and high load region of the engine.
The feature of the present embodiment that raised portion 40 is provided between the outer peripheral surface 8a of housing body 8 and the first lateral surface 1c of sprocket 1, namely, the first lateral surface 1c of proximal end portion 1b of gear part 1a facing the front plate 11, serves to enhance the flexural rigidity of proximal end portion 1b of gear part 1a.
This serves to suppress the occurrence of stress concentration to the side of proximal end portion 1b of gear part 1a facing the front plate 11, even when timing chain 42 causes a moment to housing 5 toward the crankshaft by application of a pulling load to gear part 1a from timing chain 42 toward the crankshaft along with rotation of the crankshaft while the engine is being driven because housing 5 and vane member 7 are cantilevered by camshaft 2.
Specifically, as shown in
Namely, a moment is applied to a part of gear part 1a′, where the timing chain is wound, in the direction to incline the housing body 8′, so that it is likely that stress concentration occurs at the place of connection between gear part 1a′ and housing body 8′, namely, at the part of proximal end portion 1b′ of gear part 1a′ facing the front plate 11′. This may adversely affect the endurance of housing body 8′.
Furthermore, as described above, when a moment acts on housing body 8′ in the direction to incline the gear part 1a′ so that housing body 8′ is deformed in the same direction, it is possible that the part of inner peripheral is surface 8b′ of housing body 8′ closer to front plate 11 is brought into hard press contact with seal member 38′ of each vane 16a′-16d′, causing a factor for uneven wear, and also causing a clearance C of several micrometers or so between inner peripheral surface 8b′ of housing body 8′ and seal member 38′ at the side closer to rear plate 12, thereby adversely affecting the sealing function.
The rising deformation of the part of housing body 8′ closer to rear plate 12′ may also adversely affect the sealing function of the place between the axial end surface of housing body 8′ and the part of rear plate 12′ in contact with the axial end surface of housing body 8′.
In contrast, the feature of the present embodiment that raised portion 40 is provided at first lateral surface 1c of proximal end portion 1b of gear part 1a closer to front plate 11, serves to suppress the occurrence of stress concentration at proximal end portion 1b of gear part 1a, and sufficiently suppress inclination of gear part 1a toward front plate 11 and deformation of housing body 8, and thereby suppress the endurance of housing body 8 from being adversely affected, and suppress uneven wear of seal member 38 at the side closer to front plate 11, and degrading of the sealing function of seal member 38 at the side closer to rear plate 12.
Furthermore, the feature that outer surface 40a of raised portion 40 is formed to be inclined downward from gear part 1a to outer peripheral surface 8a of housing body 8, serves to ensure the rigidity, and cause the gear part 1a to serve as a support beam, and thereby effectively suppress gear part 1a from being inclined toward front plate 11.
Specifically, the extension line X having the angle of inclination of outer surface 40a of raised portion 40 extends without crossing with inner peripheral surface 8b of housing body 8. In other words, the extension line X is within a range of wall thickness of housing body 8 except for outer peripheral surface 8a of the end surface of housing body 8 in contact with the inner end surface of front plate 11. Accordingly, the functioning of raised portion 40 as a support beam is further enhanced to further suppress deformation of housing body 8. If the extension line X having the angle of inclination of outer surface 40a of raised portion 40 crosses the inner peripheral surface 8b, the load applied to gear part 1a causes a moment to cause the raised portion 40 to be inclined toward the inner peripheral surface of housing body 8, so that the support beam function of raised portion 40 becomes insufficient to suppress deformation of housing body 8. On the other hand, if the extension line X is set to extend without crossing with inner peripheral surface 8b, the support beam function is enhanced to further suppress deformation of housing body 8.
The feature that raised portion 40 is formed to extend over the entire circumference of housing body 8 including the thinning portions 8h, 8i, serves to enhance the rigidity of the whole of proximal end portion 1b of gear part 1a and housing body 8, and thereby effectively suppress housing body 8 at the entire circumference from being deformed by constant stress concentration.
The further feature that gear part 1a of sprocket 1 is located not at the center of outer peripheral surface 8a of housing body 8 in the axial direction, but located at the place closer to rear plate 12, serves to allow raised portion 40 to be formed to have a large size at the place closer to front plate 11, and thereby further enhance the rigidity.
The feature of the present embodiment that the part of outer peripheral surface 8a of housing body 8 opposite, through the gear part 1a, to the part provided with raised portion 40, has the cylindrical shape having the outside diameter that is smaller than that of the largest outside diameter portion of raised portion 40, namely, the root portion of raised portion 40 at gear part 1a, makes it possible to enhance the capability of filling of powder metal at the opposite part of outer peripheral surface 8a of housing body 8 during sintering formation, and thereby enhance the precision of forming.
As described above, when gear part 1a is inclined toward the crankshaft (in the downward direction) about the fulcrum that is the part (first lateral surface) of proximal end portion 1b of gear part 1a closer to front plate 11, the part of housing body 8 closer to rear plate 12 is also deformed to rise. However, since the rigidity of the part of housing body 8 closer to rear plate 12 is lower, the effect of inclination of gear part 1a becomes smaller, suppressing the part of housing body 8 closer to rear plate 12 from being deformed to rise. Namely, this setting further suppresses the part of housing body 8 closer to rear plate 12 from being deformed to rise.
Preferably, the outside diameter of outer peripheral surface 8a of housing body 8 is uniform except for the gear part 1a and raised portion 40.
The feature of the present embodiment that distal end portion 17a of tubular projecting part 17 formed integrally with the front end surface of rotor 15 includes the annular groove 35 in which part of the innermost peripheral part of spiral spring 33 is fitted, serves to cause the end surface of spiral spring 33 farther from front plate 11 to be in contact with lateral wall surface 35b of annular groove 35, and thereby prevent spiral spring 33 from being released from the front side of the device, when spiral spring 33 starts to move in the forward direction of the device from outer end surface 11c of front plate 11 while spiral spring 33 is being deformed with increasing or decreasing diameter.
This feature that vane member 7 itself includes annular groove 35 in which the innermost peripheral part of spiral spring 33 engages, serves to reduce the number of parts and make it easy to manufacture and assemble the device, as compared to a case where additional parts are provided. This also serves to achieve cost reduction.
The feature of the present embodiment that second engaging end portion 33c of spiral spring 33 engages with hooded pin 14, serves to prevent spiral spring 33 from being released from the front side of the device also by hood part 14b.
The feature of the present embodiment that annular groove 35 is configured to receive engagement of only part of the innermost peripheral part of spiral spring 33 inside of annular groove 35, serves to significantly reduce a friction that may occur between spiral spring 33 and the first lateral wall surface of annular groove 35, even when spiral spring 33 moves forward into contact with the first lateral wall surface of annular groove 35, because the area of contact is small.
Although annular groove 35 is formed to extend over the substantially entire circumference of tubular projecting part 17 in the present embodiment, it is unnecessary. It is sufficient to form the annular groove 35 in a predetermined range of tubular projecting part 17 in the circumferential direction, which is required to prevent spiral spring 33 from being released from the front side of the device.
Specifically, each raised portion 40 has the same configuration including the tapering outer surface 40a as in the first embodiment, but four raised portions 40 each having an arc shape are formed separately in the circumferential direction, at relatively thin parts of housing body 8 out of the outer periphery of the base portion of each shoe 8c-8f having higher rigidity.
The feature of the present embodiment that four separate raised portions 40 are provided, not extending over the entire circumference of housing body 8, serves to significantly suppress inclination and deformation of gear part 1a and housing body 8 toward front plate 11, and also reduce the weight of the whole of housing body 8.
The feature that each raised portion 40 is provided at the corresponding relatively thin part of housing body 8, serves to enhance the rigidity of the relatively thin part, and thereby suppress the whole of housing body 8 from being deformed by inclination of gear part 1a due to a pulling load from timing chain 42. Other operation and effects are produced as in the first embodiment.
Also in this embodiment, raised portion 40 serves to suppress inclination and deformation of gear part 1a and housing body 8 toward front plate 11 as in the first embodiment, and further enhance the rigidity by the feature that raised portion 40 has the rectangular cross-section and thereby has a larger volume.
This serves to cause the raised portion 40 to further suppress inclination and deformation of housing body 8 and gear part 1a.
Although raised portion 40 is formed to extend over the entire circumference of housing body 8 as in the first embodiment, raised portions 40 may be formed separately as in the second embodiment.
Specifically, first raised portion 40 basically has the substantially identical configuration as in the first embodiment, but second raised portion 41 has a smaller size than first raised portion 40.
In the present embodiment, the provision of first raised portion 40 and second raised portion 41 serves to enhance the rigidity of each side of proximal end portion 1b of gear part 1a. Therefore, it is possible to further effectively suppress inclination of gear part 1a and deformation of housing body 8 caused by a pulling load from timing chain 42.
Also in the present embodiment, first raised portion 40 and second raised portion 41 are formed to extend over the entire circumference of housing body 8, but may be separated alternatively as in the second embodiment.
The present invention is not limited to the specific configurations of the embodiments described above, but may be also applied to valve systems for exhaust valves or valve systems for both intake valves and exhaust valves, in addition to valve systems for intake valves.
The present invention may be applied to a timing pulley as well as the timing sprocket, wherein an endless timing belt is wound around the timing pulley.
The internal combustion engine valve timing control device described above with reference to the embodiments may be implemented as follows.
A valve timing control device includes: a housing body having a cylindrical tubular shape, and including a plurality of shoes, wherein the shoes project from an inner peripheral side of the housing body; a plurality of gear parts, wherein each of the gear parts includes a proximal end portion formed integrally with an outer peripheral surface of the housing body, and wherein a transmission member is wound around the gear parts for crankshaft torque transmission; a vane member configured to be fixed to a first axial end portion of a camshaft, and mounted rotatably in the housing body, wherein the vane member includes a plurality of vanes, and wherein each of the vanes is configured to separate a space between corresponding adjacent two of the shoes into a retard hydraulic chamber and an advance hydraulic chamber; a rear plate enclosing a first axial end opening of the housing body, wherein the first axial end opening faces the camshaft; a front plate enclosing a second axial end opening of the housing body, wherein the second axial end opening is opposite to the first axial end opening, and farther from the camshaft than the first axial end opening; and a raised portion formed at least between the outer peripheral surface of the housing body and a first lateral surface of the proximal end portion of each of the gear parts, wherein the first lateral surface faces the front plate.
Preferably, the raised portion has such an outer surface that the raised portion has a shape tapering from the first lateral surface of the proximal end portion of the each of the gear parts to the outer peripheral surface of the housing body.
More preferably, the gear parts are located closer to the rear plate than a central position of the housing body in an axial direction of the housing body.
More preferably, the raised portion is formed only between the outer peripheral surface of the housing body and the first lateral surface of the proximal end portion of each of the gear parts, wherein the first lateral surface faces the front plate.
More preferably, the housing body and the gear parts are formed integrally by sintering; and the part of the outer peripheral surface of the housing body between the rear plate and the gear parts has a cylindrical shape.
More preferably, an extension of an inclined surface of the outer surface of the raised portion having the tapering shape from the gear parts to the outer peripheral surface of the housing body is out of crossing with an inner peripheral surface of the housing body.
More preferably, the raised portion is formed to extend circumferentially entirely over the outer peripheral surface of the housing body and the proximal end portion of each of the gear parts.
More preferably, an angle between the outer peripheral surface of the housing body and the outer surface of the raised portion having the tapering shape is an acute angle.
More preferably, each of the vanes includes an outer peripheral part provided with a seal member in sliding contact with an inner peripheral surface of the housing body.
More preferably, a part of the outer peripheral surface of the housing body overlapping with the shoes in a circumferential direction of the housing body is formed with a thinning portion recessed inwardly in a radial direction of the housing body; and the raised portion is formed to extend at an outer surface of the thinning portion.
More preferably, the raised portion is formed to extend in a bottom surface and an inner lateral surface of the thinning portion.
More preferably, the housing body is positioned with respect to the rear plate by a positioning pin and a positioning groove; the positioning pin is provided at one of the housing body and the rear plate; and the positioning groove is provided at another one of the housing body and the rear plate, and is configured to engage with the positioning pin in an axial direction of the housing body.
More preferably, a second raised portion is formed between the outer peripheral surface of the housing body and a side of the proximal end portion of each of the gear parts facing the rear plate.
According to another aspect, it includes: a housing body having a cylindrical tubular shape, and including a plurality of shoes and a gear part, wherein the shoes project from an inner peripheral surface of the housing body, and wherein the gear part is formed integrally with an outer peripheral surface of the housing body, and wherein a transmission member is wound around the gear part for crankshaft torque transmission; a vane member configured to be fixed to a first axial end portion of a camshaft, and mounted rotatably in the housing body, wherein the vane member includes a plurality of vanes configured to separate an internal space of the housing body into a retard hydraulic chamber and an advance hydraulic chamber in cooperation with the shoes; and a raised portion formed at least between the outer peripheral surface of the housing body and a first lateral surface of a proximal end portion of the gear part, wherein the proximal end portion is connected to the outer peripheral surface of the housing body, and wherein the first lateral surface is farther from the camshaft than a second lateral surface of the proximal end portion closer to the camshaft.
More preferably, the raised portion causes the housing body to have a higher rigidity at a first side, which is farther from the camshaft than the gear part, than at a second side closer to the camshaft than the gear part.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-001412 | Jan 2016 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/086682 | 12/9/2016 | WO | 00 |
