This invention relates to a control device and a control method for a valve timing adjustment device in which a lock pin engages in an intermediate position between the most advanced position and the most retarded position.
A valve timing adjustment device for controlling opening and closing timings of an intake or exhaust valve has conventionally been devised. Such valve timing adjustment device includes a first rotary body, a second rotary body that is relatively rotatable with respect to the first rotary body at a predetermined angle, and a lock mechanism for locking the second rotary body in an intermediate position upon engine start-up.
For example, a process needs to be followed as follows. A control device for a valve timing adjustment device according to Patent Literature 1 applies hydraulic pressure to an advancing hydraulic chamber to apply rotational force to the second rotary body in the advance direction, thereby keeping an advance-side lock pin pressed against the circumferential surface of an advance-side engagement hole. In such condition, the control device applies lock pin-release hydraulic pressure to the advance-side engagement hole and to a retard-side engagement hole, and thereby first allows a retard-side lock pin to disengage from a retard-side engagement groove. Then, the control device causes hydraulic pressure to be applied to a retarding hydraulic chamber to apply rotational force to the second rotary body in the retard direction, and thereby allows the advance-side lock pin to be released and disengaged from the circumferential surface of the advance-side engagement hole.
Patent Literature 1: WO 2015/033676 A
The control device for a valve timing adjustment device according to Patent Literature 1 needs to sequentially apply advancing hydraulic pressure, lock pin-release hydraulic pressure, and retarding hydraulic pressure to unlock the intermediate lock. Thus, it takes a long time to unlock the intermediate lock and to allow the valve timing adjustment device to operate, which presents a problem of low responsivity.
This invention has been made to solve the foregoing problem, and it is an object of the present invention to reduce the time required to unlock the intermediate lock and to allow the valve timing adjustment device to operate, and thereby to enhance responsivity.
A control device for a valve timing adjustment device according to this invention is a control device for a valve timing adjustment device that includes a first rotary body including a hydraulic chamber, a second rotary body including a vane which separates the hydraulic chamber into an advance-side section and a retard-side section, the second rotary body being relatively rotatable with respect to the first rotary body, the second rotary body being accommodated in the first rotary body, and a lock mechanism for locking the second rotary body in an intermediate position between a most advanced position and a most retarded position, the lock mechanism including a through hole formed inside the vane in an axial direction of the second rotary body, a cylindrical member having a cylindrical shape introduced into the through hole in a state in which axial sliding and rotational movement relative to the through hole are restricted, a first lock pin and a second lock pin provided coaxially with each other inside the cylindrical member, a first engagement groove and a second engagement groove which are formed in the first rotary body, and with which the first lock pin and the second lock pin are to be respectively engaged, a biasing member that biases the first lock pin toward the first engagement groove, and that biases the second lock pin toward the second engagement groove, a first lock pin-release oil passage that is formed in an outer circumferential surface of the cylindrical member or in an inner circumferential surface of the through hole, and that is to apply lock pin-release hydraulic pressure to the first engagement groove, and a second lock pin-release oil passage that is formed in the outer circumferential surface of the cylindrical member or in the inner circumferential surface of the through hole, and that is to apply, to the second engagement groove, the lock pin-release hydraulic pressure applied to the first engagement groove, in which in a state in which the first lock pin is engaged with the first engagement groove and the second lock pin is engaged with the second engagement groove to lock the second rotary body in the intermediate position, the control device causes the lock pin-release hydraulic pressure to be applied to the first lock pin-release oil passage to disengage the first lock pin from the first engagement groove, thereby making the second rotary body rotatable in an advance direction or in a retard direction, and forming a clearance communicating with the second lock pin-release oil passage, between the first engagement groove and the first lock pin; and causes hydraulic pressure to be applied to the section of the hydraulic chamber corresponding to the direction in which the second rotary body is made rotatable to rotate the second rotary body, and causes the lock pin-release hydraulic pressure in the first engagement groove to be applied through the clearance and through the second lock pin-release oil passage to the second engagement groove to disengage the second lock pin, so that the second rotary body is unlocked.
According to this invention, lock pin-release hydraulic pressure and either advancing or retarding hydraulic pressure are applied to unlock the intermediate lock, which can reduce the time required to unlock the intermediate lock and to allow the valve timing adjustment device to operate, and can thus enhance responsivity as compared to conventional ones.
To describe this invention in more detail, modes for carrying out this invention will be described below with reference to the accompanying drawings.
The casing 2 includes multiple shoes 11 projecting radially inwardly and forming multiple hydraulic chambers. A rotor 1 includes multiple vanes 12 that each separate the corresponding one of the hydraulic chambers of the casing 2 into an advancing hydraulic chamber 16 and a retarding hydraulic chamber 17. When the rotor 1 is accommodated in the casing 2, the plate 3, the casing 2, and a cover 4 are integrated together by means of screws or the like. The integration causes both sides of the casing 2 to be covered with the plate 3 and the cover 4, and the hydraulic chambers are thus sealed. These elements, i.e., the casing 2, the plate 3, and the cover 4 are included in a first rotary body. The rotor 1 is included in a second rotary body. The second rotary body is relatively rotatable with respect to the first rotary body.
The casing 2 has sprockets 2a formed on the outer circumference thereof. A timing belt (not shown) placed on these sprockets 2a transmits driving force of the crankshaft of the engine to the casing 2, thereby causing the first rotary body including the casing 2, the plate 3, and the cover 4 to rotate in synchronism with the crankshaft. Meanwhile, the rotor 1 is fixed to a camshaft 20 illustrated in
The rotor 1 includes multiple advancing oil passages 18, multiple retarding oil passages 19, and one rotor-side lock pin-release oil passage 14 each formed therein. The advancing oil passages 18 communicate with the respective advancing hydraulic chambers 16, while the retarding oil passages 19 communicate with the respective retarding hydraulic chambers 17. The rotor-side lock pin-release oil passage 14 communicates with an advance-side lock pin-release oil passage 5a described later.
Hydraulic pressure applied and removed through an oil control valve 102 (hereinafter referred to as “OCV 102”) illustrated in
In addition, one of the vanes 12 of the rotor 1 includes a lock mechanism for locking the rotor 1 in an intermediate position between the most advanced position and the most retarded position. Note that the intermediate position needs only to be a position between the most advanced position and the most retarded position, and does not need to be a midpoint in a strict sense. The lock mechanism will be described below in detail with reference to
One of the vanes 12 has a through hole 13 formed therein to penetrate the vane 12 in the axial direction of the casing 2. The press-fit member 5, having a cylindrical shape, is press-fit into the through hole 13. Being press fit into the through hole 13, the press-fit member 5 is introduced into the through hole 13 in a state in which axial sliding and rotational movement relative to the through hole 13 are restricted. Note that, as described later, the press-fit member 5 needs only to communicate with the rotor-side lock pin-release oil passage 14 of the rotor 1 to form a lock pin-release oil passage, and accordingly, there is no need to be introduced into the through hole 13 by press fitting. For example, a configuration in which a cylindrical member is inserted in the through hole 13 will allow this cylindrical member to function equivalently to the press-fit member 5 if this cylindrical member will not undergo axial sliding or rotational movement.
The advance-side lock pin 6 and the retard-side lock pin 7 are provided coaxially with each other inside the press-fit member 5. In the plate 3, an arc-shaped groove is formed which has the radius of curvature corresponding to the rotational direction of the casing 2, at a position facing the advance-side lock pin 6, and another groove is formed which projects from this arc-shaped groove in a direction to face a cutout portion 5b of the press-fit member 5 described later. These grooves together form the advance-side engagement groove 9. Moreover, in the cover 4, an arc-shaped groove is formed which has the radius of curvature corresponding to the rotational direction of the casing 2, at a position facing the retard-side lock pin 7, and another groove is formed which projects from this arc-shaped groove in a direction to face a cutout portion 5c2 of the press-fit member 5 described later. These grooves together form the retard-side engagement groove 10.
One coil spring 8, which is a biasing member, is provided between the advance-side lock pin 6 and the retard-side lock pin 7. This coil spring 8 biases the advance-side lock pin 6 toward the advance-side engagement groove 9 to engage the advance-side lock pin 6 with the advance-side engagement groove 9, and at the same time, biases the retard-side lock pin 7 toward the retard-side engagement groove 10 to engage the retard-side lock pin 7 with the retard-side engagement groove 10.
The outer circumferential surface of the press-fit member 5 has a groove formed therein that extends from the rotor-side lock pin-release oil passage 14 to the advance-side engagement groove 9, and this groove is the advance-side lock pin-release oil passage 5a. This groove is covered and sealed by the inner circumferential surface of the through hole 13 and by the inner surface of the plate 3. In addition, the press-fit member 5 has a portion facing the advance-side engagement groove 9 in the advance-side lock pin-release oil passage 5a being cut out to form the cutout portion 5b. Formation of the cutout portion 5b permits the advance-side lock pin-release oil passage 5a and the advance-side engagement groove 9 to communicate with each other. Lock pin-release hydraulic pressure applied to the rotor-side lock pin-release oil passage 14 is applied from the rotor-side lock pin-release oil passage 14 through the advance-side lock pin-release oil passage 5a and through the cutout portion 5b to the advance-side engagement groove 9. The lock pin-release hydraulic pressure applied to the advance-side engagement groove 9 causes the advance-side lock pin 6 to withdraw from the advance-side engagement groove 9 against biasing force of the coil spring 8, thereby releasing the engagement between the advance-side lock pin 6 and the advance-side engagement groove 9. During the engagement, oil accumulated in the advance-side engagement groove 9 is drained through the advance-side lock pin-release oil passage 5a to the rotor-side lock pin-release oil passage 14.
The outer circumferential surface of the press-fit member 5 also has a groove formed therein that extends from the advance-side engagement groove 9 to the retard-side engagement groove 10, and cutout portions 5c1 and 5c2 formed therein by cutting out at both end portions of the groove. The groove and the cutout portions 5c1 and 5c2 together form a retard-side lock pin-release oil passage 5c. The groove and the cutout portions 5c1 and 5c2 are covered and sealed by the inner circumferential surface of the through hole 13, by the inner surface of the plate 3, and by the inner surface of the cover 4. However, when the advance-side lock pin 6 is withdrawn from the advance-side engagement groove 9 causing the engagement to be released, a clearance is formed between the advance-side lock pin 6 and the advance-side engagement groove 9, and this clearance communicates with the cutout portion 5c1 on the advance-side engagement groove 9 side, of the retard-side lock pin-release oil passage 5c. In addition, the cutout portion 5c2 is formed at a position facing the retard-side engagement groove 10. Lock pin-release hydraulic pressure applied to the advance-side engagement groove 9 is applied from the foregoing clearance formed between the advance-side lock pin 6 and the advance-side engagement groove 9 through the retard-side lock pin-release oil passage 5c to the retard-side engagement groove 10. The lock pin-release hydraulic pressure applied to the retard-side engagement groove 10 causes the retard-side lock pin 7 to withdraw from the retard-side engagement groove 10 against biasing force of the coil spring 8, thereby releasing the engagement between the retard-side lock pin 7 and the retard-side engagement groove 10. During the engagement, oil accumulated in the retard-side engagement groove 10 is drained through the retard-side lock pin-release oil passage 5c, through the advance-side engagement groove 9, and through the advance-side lock pin-release oil passage 5a to the rotor-side lock pin-release oil passage 14.
Note that the groove of the advance-side lock pin-release oil passage 5a and the groove of the retard-side lock pin-release oil passage 5c may each have a linear shape or any shape such as a helical shape.
In addition, although the illustrated example is illustrated so that the advance-side lock pin-release oil passage 5a and the retard-side lock pin-release oil passage 5c are provided at equal intervals, both the oil passages may have any positional relationship.
As illustrated in
The advance-side lock pin 6 does not receive cam torque in the retard direction, and thus easily comes out of the advance-side engagement groove 9. In contrast, the retard-side lock pin 7 receives cam torque and is thus pressed on a retard-side side wall of the retard-side engagement groove 10, and is accordingly not easy to come out of the retard-side engagement groove 10. Thus, the lock mechanism of the first embodiment is structured to first release the engagement of the advance-side lock pin 6 not receiving cam torque, and then release the engagement of the retard-side lock pin 7. This structure enables the advance-side lock pin 6 to be reliably disengaged before the retard-side lock pin 7.
In addition, to reliably disengage the advance-side lock pin 6 before the retard-side lock pin 7, the structure described below is desirable.
Let “A” denote the length of the cutout portion 5b in the axial direction of the casing 2. In addition, let “B” denote the length of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9 in the axial direction of the casing 2. The clearance having the length “B” is a clearance to be formed when the advance-side lock pin 6 is disengaged from the advance-side engagement groove 9, and serves as an oil passage for applying the lock pin-release hydraulic pressure from the advance-side engagement groove 9 to the retard-side lock pin-release oil passage 5c. The magnitude relationship between A and B is A>B in the locked state illustrated in
A fluid drain channel 5d, which is a through hole communicating between the inside and the outside of the press-fit member 5, is formed at the position of the stopper 5f of the press-fit member 5. In addition, a fluid drain channel 5e, which is a groove communicating between the fluid drain channel 5d and a rotor-side fluid drain channel 15, is formed in the outer circumferential surface of the press-fit member 5. Clearances are inevitably formed between the press-fit member 5 and the advance-side lock pin 6 and between the press-fit member 5 and the retard-side lock pin 7 to permit the advance-side lock pin 6 and the retard-side lock pin 7 to slide. Oil and air flow into the press-fit member 5 through these clearances. The oil and air are drained through the fluid drain channel 5d and through the fluid drain channel 5e, out of the rotor-side fluid drain channel 15.
As described above, the through hole 13 included in the lock mechanism of the first embodiment is formed inside one of the vanes 12 in the axial direction of the casing 2, which is included in the second rotary body. The press-fit member 5 is a cylindrical member, and is introduced into the through hole 13 in a state in which axial sliding and rotational movement relative to the through hole 13 are restricted. The advance-side lock pin 6 and the retard-side lock pin 7 are provided coaxially with each other inside the press-fit member 5. The advance-side engagement groove 9 and the retard-side engagement groove 10 are respectively formed in the plate 3 and in the cover 4 included in the first rotary body to respectively allow the advance-side lock pin 6 and the retard-side lock pin 7 to engage therewith. The coil spring 8 biases the advance-side lock pin 6 toward the advance-side engagement groove 9, and biases the retard-side lock pin 7 toward the retard-side engagement groove 10. The advance-side lock pin-release oil passage 5a is formed in the outer circumferential surface of the press-fit member 5 to apply the lock pin-release hydraulic pressure to the advance-side engagement groove 9. The retard-side lock pin-release oil passage 5c is formed in the outer circumferential surface of the press-fit member 5 to apply the lock pin-release hydraulic pressure applied to the advance-side engagement groove 9, to the retard-side engagement groove 10. As such, the simply-shaped longitudinal grooves formed in the outer circumferential surface of the press-fit member 5 respectively serve as the advance-side lock pin-release oil passage 5a and the retard-side lock pin-release oil passage 5c. This eliminates the need for producing a lock pin-release oil passage having a complex shape inside the vane 12, and it is thus sufficient to form the through hole 13 having a simple shape in the vane 12.
In addition, the press-fit member 5 of the first embodiment has the cutout portion 5b, formed by cutting out a portion facing the advance-side engagement groove 9 in the advance-side lock pin-release oil passage 5a. In this configuration, when the advance-side lock pin 6 is engaged with the advance-side engagement groove 9, the length B of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9, the clearance communicating with the retard-side lock pin-release oil passage 5c, is less than the length A of the cutout portion 5b in the axial direction of the casing 2. Meanwhile, when the advance-side lock pin 6 is disengaged from the advance-side engagement groove 9, the length B of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9, the clearance communicating with the retard-side lock pin-release oil passage 5c, is greater than or equal to the length A of the cutout portion 5b in the axial direction of the casing 2. This enables the advance-side lock pin 6 to be reliably disengaged before the retard-side lock pin 7.
Moreover, the press-fit member 5 of the first embodiment has the fluid drain channels 5d and 5e for draining fluid between the advance-side lock pin 6 and the retard-side lock pin 7 to the outside. Meanwhile, this only requires, in the corresponding one of the vanes 12, production of a longitudinal hole communicating with the fluid drain channels 5d and 5e, i.e., the rotor-side fluid drain channel 15. A method is often used conventionally in which a transverse hole is produced in the rotor 1 to be used as the rotor-side fluid drain channel, but in the first embodiment, a longitudinal hole is produced in the rotor 1, and the longitudinal hole can be used as the rotor-side fluid drain channel 15. This enables a fluid drain channel to be implemented by an easier production operation than conventional ones.
Note that the fluid drain channel 5e may be not provided, and the fluid drain channel 5d may be structured to communicate directly with the rotor-side fluid drain channel 15.
Furthermore, the coil spring 8 of the first embodiment may have a linear spring constant or may have a nonlinear spring constant. A coil spring 8 having a nonlinear spring constant is an irregular pitch spring whose biasing force varies during expansion and contraction, or other similar spring. For example, a coil spring 8 having a nonlinear spring constant is used in such a manner that force to bias the retard-side lock pin 7 toward the retard-side engagement groove 10 is greater than force to bias the advance-side lock pin 6 toward the advance-side engagement groove 9. This can prevent a situation in which, during an unlocking operation, the retard-side lock pin 7 is disengaged from the retard-side engagement groove 10 before the advance-side lock pin 6 is disengaged from the advance-side engagement groove 9 even if the lock pin-release hydraulic pressure leaks through the clearance to the retard-side engagement groove 10.
A valve timing adjustment device 100 according to a second embodiment is structured the same as the valve timing adjustment device 100 according to the first embodiment except for the lock mechanism, and
In the first embodiment, the press-fit member 5 is structured to have the cutout portion 5b, but in the second embodiment, a recessed portion 9a is formed in place of this cutout portion 5b. Specifically, the advance-side engagement groove 9 has a recessed portion 9a, which is a recess formed in a portion facing the advance-side lock pin-release oil passage 5a. Formation of the recessed portion 9a permits the advance-side lock pin-release oil passage 5a and the advance-side engagement groove 9 to communicate with each other. The lock pin-release hydraulic pressure applied to the rotor-side lock pin-release oil passage 14 is applied from the rotor-side lock pin-release oil passage 14 through the advance-side lock pin-release oil passage 5a and through the recessed portion 9a to the advance-side engagement groove 9.
Note that similarly to the configuration on the advance side, a recessed portion 10a may be formed in the retard-side engagement groove 10 in place of the cutout portion 5c2 on the retard side. The lock pin-release hydraulic pressure applied to the advance-side engagement groove 9 is applied from the advance-side engagement groove 9 through the cutout portion 5c1, through the retard-side lock pin-release oil passage 5c, and through the recessed portion 10a to the retard-side engagement groove 10.
Let “A” denote the length of the recessed portion 9a in the axial direction of the casing 2. In addition, similarly to the first embodiment, let “B” denote the length of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9 in the axial direction of the casing 2. The magnitude relationship between A and B is A>B in the locked state illustrated in
As described above, the advance-side engagement groove 9 of the second embodiment has the recessed portion 9a, which is a recess formed in a portion facing the advance-side lock pin-release oil passage 5a. In this configuration, when the advance-side lock pin 6 is engaged with the advance-side engagement groove 9, the length B of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9, the clearance communicating with the retard-side lock pin-release oil passage 5c, is less than the length A of the recessed portion 9a in the axial direction of the casing 2. Meanwhile, when the advance-side lock pin 6 is disengaged from the advance-side engagement groove 9, the length B of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9, the clearance communicating with the retard-side lock pin-release oil passage 5c, is greater than or equal to the length A of the recessed portion 9a in the axial direction of the casing 2. This enables the advance-side lock pin 6 to be reliably disengaged before the retard-side lock pin 7.
A valve timing adjustment device 100 according to a third embodiment is structured the same as the valve timing adjustment device 100 according to the first embodiment except for the lock mechanism, and
In the first embodiment, the press-fit member 5 is structured to have the cutout portion 5b, but in the third embodiment, the recessed portion 9a described in the second embodiment is also formed in addition to this cutout portion 5b. Specifically, the advance-side engagement groove 9 has the recessed portion 9a, which is a recess formed in a portion facing the cutout portion 5b of the press-fit member 5. Formation of the cutout portion 5b and the recessed portion 9a permits the advance-side lock pin-release oil passage 5a and the advance-side engagement groove 9 to communicate with each other. The lock pin-release hydraulic pressure applied to the rotor-side lock pin-release oil passage 14 is applied from the rotor-side lock pin-release oil passage 14 through the advance-side lock pin-release oil passage 5a, through the cutout portion 5b, and through the recessed portion 9a to the advance-side engagement groove 9.
Note that similarly to the configuration on the advance side, the recessed portion 10a may be formed in the retard-side engagement groove 10 also on the retard side in addition to the cutout portion 5c2. The lock pin-release hydraulic pressure applied to the advance-side engagement groove 9 is applied from the advance-side engagement groove 9 through the cutout portion 5c1, through the retard-side lock pin-release oil passage 5c, through the cutout portion 5c2, and through the recessed portion 10a to the retard-side engagement groove 10.
Let “A” denote the length that is the sum of the length of the cutout portion 5b and the length of the recessed portion 9a in the axial direction of the casing 2. In addition, similarly to the first embodiment, let “B” denote the length of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9 in the axial direction of the casing 2. The magnitude relationship between A and B is A>B in the locked state illustrated in
As described above, the press-fit member 5 of the third embodiment has the cutout portion 5b, formed by cutting out a portion facing the advance-side engagement groove 9 in the advance-side lock pin-release oil passage 5a. In addition, the advance-side engagement groove 9 has the recessed portion 9a, which is a recess formed in a portion facing the cutout portion 5b. In this configuration, when the advance-side lock pin 6 is engaged with the advance-side engagement groove 9, the length B of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9, the clearance communicating with the retard-side lock pin-release oil passage 5c, is less than the length A, which is the sum of the length of the cutout portion 5b and the length of the recessed portion 9a, in the axial direction of the casing 2. Meanwhile, when the advance-side lock pin 6 is disengaged from the advance-side engagement groove 9, the length B of the clearance between the advance-side lock pin 6 and the advance-side engagement groove 9, the clearance communicating with the retard-side lock pin-release oil passage 5c, is greater than or equal to the length A, which is the sum of the length of the cutout portion 5b and the length of the recessed portion 9a, in the axial direction of the casing 2. This enables the advance-side lock pin 6 to be reliably disengaged before the retard-side lock pin 7.
In addition, one coil spring 8 is used in the first embodiment, but in the third embodiment, two coil springs 8a and 8b are used. The coil spring 8a, corresponding to a first coil spring, biases the advance-side lock pin 6 toward the advance-side engagement groove 9. The coil spring 8b, corresponding to a second coil spring, biases the retard-side lock pin 7 toward the retard-side engagement groove 10. Note that the biasing force of the coil spring 8b may be greater than the biasing force of the coil spring 8a. This can prevent a situation in which, during an unlocking operation, the retard-side lock pin 7 is disengaged from the retard-side engagement groove 10 before the advance-side lock pin 6 is disengaged from the advance-side engagement groove 9 even if the lock pin-release hydraulic pressure leaks through the clearance to the retard-side engagement groove 10.
A valve timing adjustment device 100 according to a fourth embodiment is structured the same as the valve timing adjustment device 100 according to the first embodiment except for the lock mechanism, and
In the first embodiment, the depth of each of the advance-side engagement groove 9 and the retard-side engagement groove 10 is constant in the relative rotational direction, but in the fourth embodiment, the advance-side engagement groove 9 includes a stepped portion 9b having at least one step formed on the retard side to cause the advance-side engagement groove 9 to have a stepped depth. In addition, the retard-side engagement groove 10 has a stepped portion 10b having at least one step formed on the advance side to cause the retard-side engagement groove 10 to have a stepped depth. Note that the depth may be stepped only on the advance side or on the retard side, or the depth may be stepped on both the advance and retard sides. When either the advance-side lock pin 6 or the retard-side lock pin 7 is in an engaged state, this causes the advance-side lock pin 6 or the retard-side lock pin 7 to abut a wall formed by the advance-side engagement groove 9 and the stepped portion 9b, or a wall formed by the retard-side engagement groove 10 and the stepped portion 10b even if the valve timing adjustment device 100 is subject to vibration, and thereby prevents relative rotation of the rotor 1.
Note that the valve timing adjustment devices 100 according to the second embodiment and the third embodiment may also be structured so that the stepped portion 9b and the stepped portion 10b are respectively formed in the advance-side engagement groove 9 and in the retard-side engagement groove 10.
The ECU 101 controls the operation of the OCV 102 to switch the status of communication between the OCV 102 and the rotor-side lock pin-release oil passage 14, the status of communication between the OCV 102 and the advancing oil passages 18, and the status of communication between the OCV 102 and the retarding oil passages 19. The OCV 102 supplies oil supplied from an oil pump (not shown) to the rotor-side lock pin-release oil passage 14, to the advancing oil passages 18, or to the retarding oil passages 19 in accordance with the control by the ECU 101. In addition, the OCV 102 drains the oil supplied to the rotor-side lock pin-release oil passage 14, to the advancing oil passages 18, or to the retarding oil passages 19 along a path opposite to the path used in the supply operation in accordance with the control by the ECU 101.
The ECU 101 is a computer or a microcomputer including a processor 101a and a memory 101b. The functions of the ECU 101 are implemented by software, firmware, or a combination of software and firmware. The software or firmware is described as a program, and is stored in the memory 101b. The processor 101a reads and executes the program stored in the memory 102b to implement the functions of the ECU 101. Specifically, the ECU 101 includes the memory 102b for storing a program that, upon execution by the processor 101a, causes the steps illustrated in the flowcharts of
A method for controlling the valve timing adjustment device 100 by the ECU 101 will next be described.
First, a procedure to unlock the lock mechanism will be described with reference to the lock mechanism of
In addition,
Upon start-up of the engine when the rotor 1 is locked in an intermediate position, that is, when the advance-side lock pin 6 and the retard-side lock pin 7 are respectively engaged with the advance-side engagement groove 9 and with the retard-side engagement groove 10 as illustrated in
At step ST1, when an unlocking request is received from the vehicle side (“YES” at step ST1), the ECU 101 causes the process to proceed to step ST2, and repeats step ST1 in the other cases (“NO” at step ST1).
At step ST2, the ECU 101 performs lock pin releasing control. Specifically, the ECU 101 controls the OCV 102 to apply lock pin-release hydraulic pressure to the rotor-side lock pin-release oil passage 14. The lock pin-release hydraulic pressure is applied through the rotor-side lock pin-release oil passage 14, through the advance-side lock pin-release oil passage 5a, and through the cutout portion 5b to the advance-side engagement groove 9. Then, as illustrated in
At step ST3, the ECU 101 starts measurement of time upon the start of performing the lock pin releasing control, and determines whether a predetermined setting time has elapsed. If the setting time has elapsed (“YES” at step ST3), the ECU 101 causes the process to proceed to step ST4, and repeats step ST3 if the setting time has not yet elapsed (“NO” at step ST3). The setting time is the required time until the advance-side lock pin 6 is disengaged from the advance-side engagement groove 9 after the lock pin-release hydraulic pressure is applied to the rotor-side lock pin-release oil passage 14. In the graphs of
At step ST4, the ECU 101 performs advance movement control. Specifically, the ECU 101 controls the OCV 102 to apply hydraulic pressure to the advancing oil passages 18. This hydraulic pressure is applied through the advancing oil passages 18 to the advancing hydraulic chambers 16. As described above, the retard-side lock pin 7 receives cam torque and is thus pressed on a retard-side side wall of the retard-side engagement groove 10, and is accordingly not easy to come out. When the advance movement control causes the rotor 1 to move in the advance direction as illustrated in
The control by the ECU 101 at steps ST1 to ST4 disengages the advance-side lock pin 6 and the retard-side lock pin 7, and thus releases the intermediate lock of the rotor 1. Then, to provide the intended actual phase, the ECU 101 controls the OCV 102 to apply hydraulic pressure to the advancing hydraulic chambers 16 or to the retarding hydraulic chambers 17, and thus causes the rotor 1 to move in the advance direction or in the retard direction.
A procedure to lock the lock mechanism will next be described with reference to the lock mechanism of
Upon stopping of the engine when the advance-side lock pin 6 and the retard-side lock pin 7 are both disengaged and thus the rotor 1 is movable in the advance direction and in the retard direction, a lock request is provided from the vehicle side to the ECU 101.
At step ST11, when a lock request is received from the vehicle side (“YES” at step ST11), the ECU 101 causes the process to proceed to step ST12, and repeats step ST11 in the other cases (“NO” at step ST11).
At step ST12, the ECU 101 controls the OCV 102 to apply lock pin-release hydraulic pressure to the rotor-side lock pin-release oil passage 14, and thus causes the lock pin-release hydraulic pressure to be applied to the advance-side engagement groove 9 and to the retard-side engagement groove 10. This prevents the advance-side lock pin 6 and the retard-side lock pin 7 from being accidentally engaged respectively with the advance-side engagement groove 9 and the retard-side engagement groove 10 during advance movement of the rotor 1 at step ST13 that follows.
At step ST13, the ECU 101 performs advance movement control. Specifically, the ECU 101 controls the OCV 102 to apply hydraulic pressure through the advancing oil passages 18 to the advancing hydraulic chambers 16, and to remove hydraulic pressure in the retarding hydraulic chambers 17 through the retarding oil passages 19, and thus causes the rotor 1 to move to the most advanced position.
At step ST14, the ECU 101 determines whether the actual phase has reached the most advanced position as illustrated in
At step ST15, the ECU 101 performs retard movement control. Specifically, the ECU 101 controls the OCV 102 to apply hydraulic pressure through the retarding oil passages 19 to the retarding hydraulic chambers 17, and to remove hydraulic pressure in the advancing hydraulic chambers 16 through the advancing oil passages 18. This causes the rotor 1 to move in the retard direction as illustrated in
At step ST16, the ECU 101 controls the OCV 102 to remove the lock pin-release hydraulic pressure in the advance-side engagement groove 9 and in the retard-side engagement groove 10 through the rotor-side lock pin-release oil passage 14, concurrently with the retard movement control at step ST15. This causes the rotor 1 to move in the retard direction, and thus causes the retard-side lock pin 7 to first engage with the stepped portion 10b as illustrated in
At step ST17, the ECU 101 determines whether the actual phase has stopped at the intermediate position. If the actual phase is at the intermediate position (“YES” at step ST17), the ECU 101 determines that the rotor 1 is locked in the intermediate position, in which case the advance-side lock pin 6 is engaged with the advance-side engagement groove 9, and the retard-side lock pin 7 is engaged with the retard-side engagement groove 10 as illustrated in
At step ST18, the ECU 101 determines whether the actual phase is on the retard side with respect to the intermediate position. If the actual phase is on the retard side with respect to the intermediate position, this indicates that engagement has failed due to the advance-side lock pin 6 and the retard-side lock pin 7 passing over the advance-side engagement groove 9 and the retard-side engagement groove 10 before the lock pin-release hydraulic pressure is fully removed from the advance-side engagement groove 9 and from the retard-side engagement groove 10, or engagement has been unsuccessful even though the lock pin-release hydraulic pressure has been fully removed. Accordingly, if the actual phase is on the retard side with respect to the intermediate position (“YES” at step ST18), the ECU 101 causes the process to return to step ST12, and then performs the lock control routine again. Otherwise, if the actual phase is not on the retard side with respect to the intermediate position, this indicates that the advance-side lock pin 6 and the retard-side lock pin 7 have not yet reached the advance-side engagement groove 9 and the retard-side engagement groove 10. Accordingly, if the actual phase is not on the retard side with respect to the intermediate position (“NO” at step ST18), the ECU 101 causes the process to return to step ST17.
As described above, when the intermediate lock of the rotor 1 is to be unlocked in the fifth embodiment, the ECU 101 causes lock pin-release hydraulic pressure to be applied to the advance-side lock pin-release oil passage 5a thus to disengage the advance-side lock pin 6 from the advance-side engagement groove 9, thereby making the casing 2 rotatable in the advance direction, and at the same time, forming a clearance communicating with the retard-side lock pin-release oil passage 5c, between the advance-side lock pin 6 and the advance-side engagement groove 9. Next, the ECU 101 causes hydraulic pressure to be applied to the advancing hydraulic chambers 16 thus to rotate the rotor 1, and causes the lock pin-release hydraulic pressure in the advance-side engagement groove 9 to be applied through the clearance and through the retard-side lock pin-release oil passage 5c to the retard-side engagement groove 10 to disengage the retard-side lock pin 7. Thus, the ECU 101 can reduce the time required to unlock the intermediate lock, and to allow the valve timing adjustment device 100 to operate, and can thus enhance responsivity as compared to conventional ones.
In addition, when the rotor 1 is to be locked by the intermediate lock in the fifth embodiment, the ECU 101 causes lock pin-release hydraulic pressure to be applied to the advance-side engagement groove 9 and to the retard-side engagement groove 10, and then causes hydraulic pressure to be applied to the advancing hydraulic chambers 16, thereby causing the rotor 1 to rotate to the most advanced position. Next, the ECU 101 causes the lock pin-release hydraulic pressure to be removed from the advance-side engagement groove 9 and from the retard-side engagement groove 10, and causes hydraulic pressure to be applied to the retarding hydraulic chambers 17 to rotate the rotor 1 toward the intermediate position, thereby engaging the advance-side lock pin 6 with the advance-side engagement groove 9 and engaging the retard-side lock pin 7 with the retard-side engagement groove 10. Thus, by moving the rotor 1 from the most advanced position in the retard direction, the ECU 101 allows the advance-side lock pin 6 and the retard-side lock pin 7 to automatically engage with the advance-side engagement groove 9 and with the retard-side engagement groove 10.
A valve timing adjustment device 100 according to a sixth embodiment is structured the same as the valve timing adjustment devices 100 according to the first to fourth embodiments except for the lock mechanism, and
In the first to fourth embodiments, the press-fit member 5 is structured to have the advance-side lock pin-release oil passage 5a, but in the sixth embodiment, the through hole 13 is structured to have an advance-side lock pin-release oil passage 13a. As illustrated in
Similarly, the press-fit member 5 is structured to have the retard-side lock pin-release oil passage 5c, but the through hole 13 may be structured to have a retard-side lock pin-release oil passage 13b. As illustrated in
In the sixth embodiment, the simply-shaped longitudinal grooves formed in the inner circumferential surface of the through hole 13 serve as the advance-side lock pin-release oil passage 13a and the retard-side lock pin-release oil passage 13b. This eliminates the need for producing a lock pin-release oil passage having a complex shape inside the vane 12.
The foregoing description describes the advance side as the “first” side, which is the upstream side where the lock pin-release hydraulic pressure is applied first, and the retard side as the “second” side, which is the downstream side. Accordingly, the term “first lock pin” corresponds to the advance-side lock pin 6, and the term “second lock pin” corresponds to the retard-side lock pin 7. In addition, the term “first engagement groove” corresponds to the advance-side engagement groove 9, and the term “second engagement groove” corresponds to the retard-side engagement groove 10. Moreover, the term “first lock pin-release oil passage” corresponds to the advance-side lock pin-release oil passage 5a or 13a, and the term “second lock pin-release oil passage” corresponds to the retard-side lock pin-release oil passage 5c or 13b.
However, depending on the attachment direction of the valve timing adjustment device 100 to the engine, the advance direction and the retard direction may be opposite. Specifically, the advance-side lock pin 6 and the advance-side engagement groove 9 function as the retard-side lock pin and the retard-side engagement groove, and the retard-side lock pin 7 and the retard-side engagement groove 10 function as the advance-side lock pin and the advance-side engagement groove. In addition, the advance-side lock pin-release oil passages 5a and 13a each function as the retard-side lock pin-release oil passage, and the retard-side lock pin-release oil passages 5c and 13b each function as the advance-side lock pin-release oil passage. In this case, the retard side is represented by the term “first”, and the advance side is represented by the term “second”. In addition, the advance-side lock pin 6 that functions as the retard-side lock pin is to be first disengaged, and the retard-side lock pin 7 that functions as the advance-side lock pin is to then be disengaged. Note that the advance-side lock pin 6 that functions as the retard-side lock pin receives cam torque, and thus is not easy to come out. Accordingly, it is desirable to use the coil spring 8 having a nonlinear spring constant or the two coil springs 8a and 8b in such a manner that the advance-side lock pin 6 that functions as the retard-side lock pin is biased with less force, and the retard-side lock pin 7 that functions as the advance-side lock pin is biased with greater force, thereby allowing the advance-side lock pin 6 that functions as the retard-side lock pin to be reliably disengaged first.
In a case in which the advance direction and the retard direction are opposite, the ECU 101 performs retard movement control at step ST4 in the flowchart illustrated in
Note that the present invention covers any combination of the foregoing embodiments, modification of any component in the embodiments, or omission of any component in the embodiments that falls within the scope of the invention.
A control device for a valve timing adjustment device according to this invention is configured to lock the rotor in an intermediate position by means of two lock pins, and is therefore suitable for use as a control device for a valve timing adjustment device that adjusts opening and closing timings of the intake valve and the exhaust valve of an engine.
1: rotor (second rotary body), 2: casing (first rotary body), 2a: sprocket, 3: plate (first rotary body), 4: cover (first rotary body), 5: press-fit member (cylindrical member), 5a, 13a: advance-side lock pin-release oil passage (first lock pin-release oil passage), 5b, 5c1, 5c2: cutout portion, 5c, 13b: retard-side lock pin-release oil passage (second lock pin-release oil passage), 5d, 5e: fluid drain channel, 5f: stopper, 6: advance-side lock pin (first lock pin), 7: retard-side lock pin (second lock pin), 8, 8a, 8b: coil spring (biasing member), 9: advance-side engagement groove (first engagement groove), 9a, 10a: recessed portion, 9b, 10b: stepped portion, 10: retard-side engagement groove (second engagement groove), 11: shoe, 12: vane, 13: through hole, 14: rotor-side lock pin-release oil passage, 15: rotor-side fluid drain channel, 16: advancing hydraulic chamber, 17: retarding hydraulic chamber, 18: advancing oil passage, 19: retarding oil passage, 20: camshaft, 100: valve timing adjustment device, 101: ECU (control device), 101a: processor, 101b: memory, 102: OCV.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2018/007310 | 2/27/2018 | WO | 00 |