Patent Application
20130139916
The present invention relates to an oil pressure control apparatus for controlling the pressure of oil that is ejected from a pump driven by the rotation of an engine and is supplied to constituent portions in the engine.
As described in PTL 1, there is a conventional oil pressure control apparatus, including: a pump that ejects oil by being driven by the rotation of an engine (an “oil pump” in this document); a valve timing control device having a driving-side rotatable member (an “outer rotor” in this document) that rotates in synchronization with a crankshaft and a following-side rotatable member (an “inner rotor” in this document) that is disposed in coaxial with the driving-side rotatable member and that rotates in synchronization with a camshaft, wherein a relative rotational phase of the following-side rotatable member with respect to the driving-side rotatable member is displaced according to supply or discharge of oil; and an engine lubricating device that lubricates constituent portions in the engine using the oil supplied by the pump.
The invention described in PTL 1 includes a flow passage area adjusting portion (a “priority valve” in this document) that, when the pressure of oil acting on the valve timing control device is low, limits the flow rate of oil from the pump to the engine lubricating device, thereby giving priority to the oil supply from the pump to the valve timing control device. Accordingly, the pressure of oil acting on the valve timing control device is ensured on a priority basis when the number of rotations of the pump is low, and, thus, the valve timing control device can be properly actuated without an electrically-driven pump for assisting the pump.
However, according to the invention described in PTL 1, the flow passage area adjusting portion is configured including a valve member and a retainer, and requires a space that allows each of the valve member and the retainer to slide. Accordingly, the size of the flow passage area adjusting portion increases, and there is room for improvement in mountability.
It is an object of the present invention to provide an oil pressure control apparatus in which the size of a flow passage area adjusting portion can be reduced, thereby having an improved mountability in an engine.
A first aspect of the present invention is directed to an oil pressure control apparatus, including: a pump that ejects oil by being driven by rotation of an engine; a first flow passage that interconnects the pump and a first predetermined portion; a second flow passage that is branched from the first flow passage and that supplies oil to a second predetermined portion, which is different from the first predetermined portion; and a flow passage area adjusting portion that is provided in the second flow passage, and that increases a flow passage area of the second flow passage when a pressure of oil in the second flow passage increases and reduces the flow passage area when the pressure of the oil decreases; wherein the flow passage area adjusting portion is configured including a spool that is formed such that a first pressure receiving face and a second pressure receiving face having an area smaller than that of the first pressure receiving face oppose each other with the second flow passage interposed therebetween, and that can move according to a pressure of oil in the second flow passage, and a biasing member that biases the spool in a direction from the first pressure receiving face to the second pressure receiving face.
With this configuration, the spool receives a force obtained by multiplying the pressure of oil in the second flow passage by a difference between the areas of the first pressure receiving face and the second pressure receiving face in a direction toward the first pressure receiving face, and a biasing force by the biasing member in a direction toward the second pressure receiving face. When the pressure of oil in the second flow passage is small, the biasing force by the biasing member predominates, the spool moves toward the second pressure receiving face, and the flow passage area of the second flow passage decreases. As the pressure of oil in the second flow passage increases, the spool moves toward the first pressure receiving face resisting the biasing force, and the flow passage area of the second flow passage increases.
Accordingly, when the pressure of oil supplied from the pump is small, the flow passage area of the second flow passage decreases, and, thus, the amount of oil supplied to the second predetermined portion (e.g., the main gallery (M/G)) can be reduced, so that a sufficient amount of oil can be supplied to the first predetermined portion. On the other hand, when the pressure of oil supplied from the pump increases, since a sufficient amount of oil has been supplied to the first predetermined portion, the amount of oil supplied to the main gallery is increased, so that constituent portions in the engine can be reliably cooled down and lubricated.
With the above-described configuration, the function of adjusting the flow passage area of the second flow passage by the flow passage area adjusting portion is realized only by moving the spool. Accordingly, compared with a conventional flow passage area adjusting portion including a spool and a retainer, the size of the flow passage area adjusting portion can be reduced, and, thus, the entire oil pressure control apparatus including this flow passage area adjusting portion can have an improved mountability in an engine.
According to a second aspect, a circumferential edge portion of the first pressure receiving face is provided with a wall portion that is projected toward the second pressure receiving face.
With the oil pressure control apparatus according to the present invention, oil that flows on the upstream side in the second flow passage flows into a flow passage space of the spool formed between the first pressure receiving face and the second pressure receiving face, and then flows out from the flow passage space to the downstream side in the second flow passage. In a state in which the spool has narrowed the flow passage area of the second flow passage, if oil that flows from the upstream side in the second flow passage into the flow passage space has a velocity component oriented toward the second pressure receiving face, when the spool moves toward the first pressure receiving face so as to increase the flow passage area, the velocity component may obstruct the movement and cause a failure in the operation of the spool.
With the above-described configuration, a circumferential edge portion of the first pressure receiving face is provided with a wall portion that is projected toward the second pressure receiving face. Accordingly, when oil flows from the upstream side in the second flow passage via a clearance between the wall portion and the valve body into the flow passage space of the spool, a velocity component oriented from the tip end of the wall portion toward the first pressure receiving face is also generated. As a result, this velocity component and the velocity component oriented toward the second pressure receiving face cancel each other. Accordingly, the spool can be properly actuated without being affected by the flow of oil.
According to a third aspect, an inner circumferential edge portion at a tip end of the wall portion is chamfered.
If an inner circumferential edge portion at the tip end of the wall portion is chamfered as in this configuration, when oil flows from the upstream side in the second flow passage via a clearance between the wall portion and the valve body into the flow passage space of the spool, a velocity component oriented from the tip end of the wall portion toward the first pressure receiving face is more easily generated. As a result, this velocity component and the velocity component oriented toward the second pressure receiving face more reliably cancel each other. Accordingly, the spool can be more reliably properly actuated without being affected by the flow of oil.
According to a fourth aspect, a valve body that accommodates the spool is provided with an inclined portion with which a flow direction of oil flowing through the second flow passage is directed toward the first pressure receiving face.
With this configuration, the inclined portion causes oil that flows on the upstream side in the second flow passage to have a velocity component oriented toward the first pressure receiving face in the flow passage space of the spool, and, thus, this velocity component and the velocity component oriented toward the second pressure receiving face cancel each other. Accordingly, the spool can be properly actuated without being affected by the flow of oil.
According to a fifth aspect, a biasing force of the biasing member is larger than a pressing force in a direction for increasing the flow passage area of the second flow passage, which is caused to act by a pressure of oil in the second flow passage while the engine is idling.
With this configuration, while the engine is idling, the biasing force by the biasing member predominates the pressing force applied by the pressure of oil in the second flow passage, and, thus, oil can be supplied to the first predetermined portion on a priority basis over the second predetermined portion. Accordingly, this configuration is preferable in the case in which the first predetermined portion requires the supply of oil immediately after start of the engine.
According to a sixth aspect, the first predetermined portion is a valve timing control device including: a driving-side rotatable member that rotates in synchronization with a crankshaft; and a following-side rotatable member that is disposed in coaxial with the driving-side rotatable member and that rotates in synchronization with a camshaft; wherein a relative rotational phase of the following-side rotatable member with respect to the driving-side rotatable member is displaced according to supply or discharge of oil.
If the first predetermined portion is the valve timing control device as in this configuration, the amount of oil supplied to the valve timing control device can be adjusted using the oil pressure control apparatus according to the present invention according to the pressure of oil in the second flow passage. As a result, the valve timing can be properly controlled, and the efficiency of the engine is improved.
According to a seventh aspect, in a case in which an oil temperature is lower than a predetermined first set temperature or is higher than a predetermined second set temperature, a control valve of the valve timing control device is switched to a predetermined valve position, so that oil is supplied from the first flow passage to a rear face of the second pressure receiving face, and the flow passage area of the second flow passage is kept in a maximum state.
For example, immediately after start of the engine, the number of rotations of the engine is low, the oil temperature is low, and, thus, the oil viscosity is high, and the oil flowability is poor. Immediately after start of the engine, the temperature in the engine main body is low, and the intake air temperature is also low, and, thus, the valve timing control device does not necessarily have to be actuated. That is to say, immediately after start of the engine, the valve timing control device does not require the oil pressure so much, whereas the main gallery requires oil for lubrication.
Thus, as in the above-described configuration, if the oil temperature is lower than a predetermined first set temperature, oil is supplied from the first flow passage to the rear face of the second pressure receiving face, and the flow passage area of the second flow passage is kept in a maximum state, and, thus, oil can be supplied to the main gallery on a priority basis.
On the other hand, if the temperature of oil becomes high, the oil viscosity decreases, and the amount of oil that leak (is exuded) from small gaps between constituent components may increase, and the oil pressure may not efficiently act on the valve timing control device. In order to actuate the valve timing control device in such a case, it is necessary to increase the size of the pump, thereby increasing the ejection pressure from the pump. That is to say, a power for driving the pump becomes necessary, and the fuel efficiency of the engine may be poor instead.
Thus, as in the above-described configuration, if the oil temperature is higher than a predetermined second set temperature, oil is supplied from the first flow passage to the rear face of the second pressure receiving face, and the flow passage area of the second flow passage is kept in a maximum state. Accordingly, the amount of oil supplied to the valve timing control device is minimized, and the pump can be suppressed from acting in vain.
Furthermore, with the above-described configuration, the control valve of the valve timing control device is used in order to supply oil from the first flow passage to the rear face of the second pressure receiving face, and, thus, a dedicated switch valve is not necessary, and an oil pressure control apparatus that is advantageous in terms of the cost and the mountability can be obtained.
According to an eighth aspect, in a case in which an oil temperature is higher than a predetermined second set temperature, a thermosensor control portion including thermowax that is expanded according to an increase in the temperature is actuated, so that oil is supplied from the second flow passage to a rear face of the second pressure receiving face, and the flow passage area of the second flow passage is kept in a maximum state.
For example, in the case in which the first predetermined portion is the valve timing control device, as described above, it is desirable that the amount of oil supplied to the valve timing control device is minimized if the temperature of oil becomes high. With this configuration, if the oil temperature is higher than a predetermined second set temperature, oil is supplied from the second flow passage to the rear face of the second pressure receiving face, and the flow passage area of the second flow passage is kept in a maximum state. Accordingly, the amount of oil supplied to the valve timing control device is minimized, and the pump can be suppressed from acting in vain.
Furthermore, with the above-described configuration, the thermosensor control portion is actuated by the thermowax. Thus, for example, compared with an electrical configuration including a temperature sensor and an electrically-driven actuator, the configuration is not complicated, and the apparatus seldom breaks down. Furthermore, since this configuration depends on the properties of a material, the displacement is to some extent unambiguously, and the reliability of the displacement is high regardless of the simple configuration. Furthermore, with this configuration, the thermosensor control portion only has the function of switching the oil passages, and, thus, large displacement does not have to occur in the thermosensor control portion, and the size of the oil pressure control apparatus can be reduced.
According to a ninth aspect, in the thermosensor control portion, an arrangement space containing a thermosensor main body portion that accommodates the thermowax is provided with an oil supply passage that supplies oil from the second flow passage.
With this configuration, oil is supplied from the second flow passage to the arrangement space containing the thermosensor main body portion that accommodates the thermowax, and, thus, the oil temperature is easily transmitted to the thermowax, and the sensitivity of the thermosensor control portion to a change in the oil temperature is improved. Accordingly, a situation can be avoided in which, although the oil temperature becomes higher than the second set temperature, the thermosensor control portion is not actuated, so that oil is continuously supplied to the first predetermined portion, and the pump acts in vain.
According to a tenth aspect, an oil return passage through which oil flows from the arrangement space to a downstream side in the second flow passage is provided.
With this configuration, the flow of oil is established from the second flow passage via the arrangement space and back to the downstream side in the second flow passage. Accordingly, oil having the function of transmitting heat to the thermowax accommodated in the thermosensor main body portion is supplied to the second predetermined portion as it is, and, thus, oil is not wasted. Furthermore, a situation can be avoided in which the oil pressure in the arrangement space becomes too large, so that a large load is applied to constituent components of the thermosensor control portion.
According to an eleventh aspect, a cup-shaped thermosensor accommodating member covers the thermosensor main body portion that is provided on a placement face of a valve body, and a clearance is formed between an end face of the thermosensor accommodating member and the placement face.
With this configuration, merely with a configuration in which a dimensional relationship between the thermosensor accommodating member and the thermosensor main body portion is properly set and a clearance is provided between the end face of the thermosensor accommodating member and the placement face, oil can be supplied via this clearance to the arrangement space. Accordingly, complex oil passages do not have to be formed in order to supply oil to the arrangement space, the configuration of the thermosensor control portion can be made simple.
According to a twelfth aspect, the thermosensor main body portion is provided with a movable member that supports the thermosensor accommodating member and that is projected when the thermowax is expanded, and, in a case in which the thermosensor accommodating member is moved according to the projection of the movable member, a ring-shaped oil passage formed on an outer circumferential face of the thermosensor accommodating member is interconnected to the second flow passage, so that oil is supplied to a rear face of the second pressure receiving face.
With this configuration, the thermosensor accommodating member is moved at the same time when the thermowax is expanded and the movable member is projected, and oil is supplied to the rear face of the second pressure receiving face. Accordingly, if the oil temperature becomes higher than the second set temperature, the flow passage area of the second flow passage can be set more promptly at a maximum state. Furthermore, constituent components such as a temperature sensor and an electrically-driven actuator are not necessary in order to realize this configuration, and, thus, a configuration that is advantageous in terms of the mountability and the cost can be obtained.
According to a thirteenth aspect, in a state in which the spool has narrowed the second flow passage to a minimum, oil that flows on an upstream side in the second flow passage can flow into a flow passage space formed between the first pressure receiving face and the second pressure receiving face, and cannot flow out from the flow passage space to a downstream side in the second flow passage.
With this configuration, in a state in which the spool has narrowed the second flow passage to a minimum, oil does not flow from the flow passage space to the downstream side in the second flow passage. That is to say, in this state, the upstream side and the downstream side in the second flow passage with respect to the flow passage area adjusting portion are interconnected to each other only via one path through the heat transmission oil passage, the arrangement space, and the oil return passage. Accordingly, compared with a case in which a plurality of paths are present, the pressure of oil supplied to the second predetermined portion can be easily adjusted.
a) shows a graph of a relationship between the oil temperature and the ON/OFF state of an OCV,
a) shows a graph of a relationship between the oil temperature and the operation state of a flow passage area adjusting portion,
Hereinafter, embodiments in which the present invention has been applied as an oil pressure control apparatus for an automobile engine will be described with reference to the drawings. In the embodiments, a description will be given assuming that a “first predetermined portion” in the present invention is a valve timing control device on the intake valve side.
As shown in
When the rotational driving force of a crankshaft (not shown) is transmitted, the pump 1 is mechanically driven to eject oil. As shown in
The oil discharged from the valve timing control device 2 is returned via the OCV 5 and an oil return passage 11B to the oil pan 1a. The oil that has been supplied to the main gallery 8 is transmitted via its cover (not shown) and the like and is recovered to the oil pan 1a. Also, oil that leaks from the valve timing control device 2 is transmitted via its cover and the like and is recovered to the oil pan 1a.
As shown in
[Housing and Inner Rotor]
As shown in
When the crankshaft is rotationally driven, the rotational driving force is transmitted via a power transmission member 102 to the timing sprocket 21d, and the housing 21 is rotationally driven in a rotational direction S shown in
As shown in
As shown in
As shown in
[Lock Mechanism]
When the pressure of oil is not stable immediately after start of the engine, the lock mechanism 27 locks the relative rotational phase at the most retarded phase by holding the housing 21 and the inner rotor 22 at predetermined relative positions. As a result, the engine can be properly started, and no backlash of the inner rotor 22 is caused by a displacement force based on a cam torque variation at the time of start or during idle running of the engine.
As shown in
When oil has been discharged from the lock groove 27b, the lock members 27a can be projected into the lock groove 27b. As shown in
The OCV 5 is of an electromagnetic control type, and can perform control of oil between supply, discharge, and block of supply and discharge to and from the advance chamber interconnecting passages 25 and the retard chamber interconnecting passages 26. The OCV 5 is configured as a spool type, and operates according to an ECU 7 (engine control unit) controlling the amount of electricity fed. The OCV 5 can perform control such as supplying oil to the advance oil passage 12A and discharging oil from the retard oil passage 12B, discharging oil from the advance oil passage 12A and supplying oil to the retard oil passage 12B, and blocking supply and discharge of oil to and from the advance oil passage 12A and the retard oil passage 12B.
The control that supplies oil to the advance oil passage 12A and discharges oil from the retard oil passage 12B is “advance control”. When the advance control is performed, the vanes 22a relatively rotate with respect to the outer rotor 21b in the advance direction S1, and the relative rotational phase is displaced to the advance side. The control that discharges oil from the advance oil passage 12A and supplies oil to the retard oil passage 12B is “retard control”. When the retard control is performed, the vanes 22a relatively rotate with respect to the outer rotor 21b in a retard direction S2, and the relative rotational phase is displaced to the retard side. When the control that blocks supply and discharge of oil to and from the advance oil passage 12A and the retard oil passage 12B is performed, the relative rotational phase can be kept at any phase.
Note that setting are made such that the advance control can be performed when electricity is fed to the OCV 5, and the retard control can be performed when the feeding of electricity to the OCV 5 is stopped. Furthermore, the opening degree of the OCV 5 is set by adjusting the duty cycle of electrical power supplied to the electromagnetic solenoid. Accordingly, the amount of oil supplied and discharged can be fine-adjusted.
In this manner, the OCV 5 is controlled such that oil is supplied and discharged to and from the advance chambers 24a and the retard chambers 24b, and the amount of oil supplied and discharged is fixed, and causes the pressure of the oil to act on the vanes 22a. Accordingly, the relative rotational phase is displaced in the advance direction or the retard direction, or kept at any phase.
Hereinafter, an operation of the valve timing control device 2 will be described with reference to
Although not shown, a crank angle sensor that detects the rotating angle of the crankshaft of the engine and a camshaft angle sensor that detects the rotating angle of the camshaft 101 are provided. The ECU 7 detects the relative rotational phase from the detection results from the crank angle sensor and the camshaft angle sensor, and determines a phase at which the relative rotational phase is set. Furthermore, the ECU 7 is provided with a signal system that acquires ON/OFF information of an ignition key, information from an oil temperature sensor that detects oil temperature, and the like. Furthermore, a memory of the ECU 7 stores control information of optimum relative rotational phases according to running states of the engine. The ECU 7 controls the relative rotational phase based on information on the running state (engine rotational velocity, coolant temperature, etc.) and the above-described control information.
As shown in
Before stopping the engine, the mode has been set to idle running, and, thus, the relative rotational phase is at the most retarded phase. At that time, at least the lock member 27a on the advance side is projected into the lock groove 27b. Then, when the ignition key is turned off, backlash of the inner rotor 22 is caused by a cam torque variation, and, thus, the lock member 27a on the retard side is also projected into the lock groove 27b, and the locked state is provided. Accordingly, the engine can be properly started next time.
Hereinafter, the flow passage area adjusting portion 3 will be described in detail with reference to
Between the rear face of the first pressure receiving face 31a and the valve body 33, a spring accommodating space 35 is formed in which a spring 32 is accommodated as a “biasing member” and always biases the spool 31 in a direction from the first pressure receiving face 31a to the second pressure receiving face 31b. The valve body 33 is configured by a body main body 33a and a stopper member 33b. The stopper member 33b is screwed onto one end portion of the body main body 33a in a state in which the spool 31 and the spring 32 are accommodated inside the body main body 33a. The outer diameter of the spool 31 is substantially equal to the inner diameter of the body main body 33a. A side wall of the body main body 33a is provided with two flow opening portions 33c that are connected to the lubricating oil passage 13, and the flow passage area of the lubricating oil passage 13 is adjusted by causing the spool 31 accommodated in the valve body 33 to be projected into and withdrawn from the lubricating oil passage 13.
A breather hole 33d is formed in an end portion of the valve body 33 on the side of the first pressure receiving face 31a. If the spring accommodating space 35 is configured as a hermetically-sealed space, the spool 31 cannot smoothly move toward the first pressure receiving face 31a, which may obstruct the operation of the spool 31. Thus, if the spring accommodating space 35 is opened to the outside by forming the breather hole 33d, the spool 31 can be smoothly actuated.
An operating opening portion 33e is formed in an end portion of the valve body 33 on the side of the second pressure receiving face 31b. As shown in
The spool 31 is configured such that the area of the first pressure receiving face 31a is larger than the area of the second pressure receiving face 31b. Accordingly, the spool 31 receives a force calculated following the formula “[Pressure of oil in the lubricating oil passage 13]×[(Area of the first pressure receiving face 31a)−(Area of the second pressure receiving face 31b)]” (hereinafter, referred to as a “force Fs”) in a direction from the second pressure receiving face 31b to the first pressure receiving face 31a, and a biasing force of the spring 32 (hereinafter, referred to as a “biasing force Fp”) in a direction from the second pressure receiving face 31b to the first pressure receiving face 31a. When the pressure of oil in the lubricating oil passage 13 increases and the force Fs becomes larger than the biasing force Fp, the spool 31 starts to move in a direction from the second pressure receiving face 31b to the first pressure receiving face 31a.
In this manner, with the action of the pressure of oil in the lubricating oil passage 13, the spool 31 can slide, at a maximum, between the state shown in
Furthermore, when the pressure of oil in the operating oil passage 14 acts on the spool 31, the rear face of the second pressure receiving face 31b receives a force in a direction from the second pressure receiving face 31b to the first pressure receiving face 31a. The pressure of oil in the operating oil passage 14 acts on the entire rear face of the second pressure receiving face 31b, and, thus, a large force can be easily generated, and the lubricating oil passage 13 can be reliably kept in the fully opened state resisting the biasing force Fp as shown in
As described above, with the action of the pressure of oil in the lubricating oil passage 13 or the action of the pressure of oil in the lubricating oil passage 13 and the pressure of oil in the operating oil passage 14, the spool 31 slides inside the valve body 33, and the flow passage area of the lubricating oil passage 13 is adjusted. That is to say, the function of adjusting the flow passage area of the lubricating oil passage 13 by the flow passage area adjusting portion 3 is realized only by moving the spool 31. Accordingly, compared with a conventional flow passage area adjusting portion including a spool and a retainer, the size of the flow passage area adjusting portion 3 can be reduced, and, thus, the entire oil pressure control apparatus can have an improved mountability in the engine.
In a state in which the spool 31 has narrowed the flow passage area of the lubricating oil passage 13 as shown in
Thus, in this embodiment, as shown in
Furthermore, in this embodiment, an inner circumferential edge portion at a tip end of the wall portion 31d is chamfered to form a tapered face 31e. Accordingly, when oil flows from the upstream side in the lubricating oil passage 13 via a clearance between the wall portion 31d and the valve body 33 into the flow passage space 34, a velocity component oriented from the tip end of the wall portion 31d toward the first pressure receiving face 31a is more easily generated. As a result, this velocity component and the velocity component oriented toward the second pressure receiving face 31b more reliably cancel each other. Accordingly, the spool 31 can be more reliably properly actuated without being affected by the flow of oil.
Instead of providing the wall portion 31d, or, in addition to providing the wall portion 31d, it is also possible to provide an inclined portion 33f on the valve body 33 as shown in
Note that, giving priority to ease in processing, the wall portion 31d and the inclined portion 33f shown in
Hereinafter, an operation of the oil pressure control apparatus will be described with reference to the drawings. Note that “II”, “III”, “IV”, and “V” in
Immediately after start of the engine, the valve timing control device 2 does not have to be actuated, and does not require the oil pressure. On the other hand, the main gallery 8 requires oil as lubricating oil in order to start the operation. Thus, if the oil temperature is lower than a predetermined first set temperature T1, electricity is not fed to the OCV 5 (OFF), as shown in
b) shows relationships between the pressure of oil ejected from the pump 1, the pressure of oil supplied to the valve timing control device 2, and the pressure of oil supplied to the main gallery 8 at that time. As shown in the graphs, the pressure of oil supplied to the valve timing control device 2 and the pressure of oil supplied to the main gallery 8 both follow an increase in the pressure of oil ejected from the pump 1.
After the oil temperature becomes higher than the predetermined first set temperature T1 and the warm-up has been completed, if the accelerator is depressed, electricity is fed to the OCV 5 (ON), and the mode is shifted to an advance control state. Accordingly, the oil pressure is required in order to stably start the valve timing control device 2. However, since the OCV 5 is in the advanced state, the advance oil passage 12A is connected to the oil ejection passage 11A, and the retard oil passage 12B is connected to the oil return passage 11B. Accordingly, the pressure of oil in the operating oil passage 14 is rapidly lowered. Furthermore, even if the oil temperature increases, the number of rotations of the engine is low, and, thus, the pressure of oil ejected from the pump 1 is still low, and the pressure of oil acting on the lubricating oil passage 13 is low. Thus, as shown in
Subsequently, when the number of rotations of the engine increases and the pressure of oil ejected from the pump 1 increases, the pressure of oil in the lubricating oil passage 13 also increases, and the spool 31 gradually opens the lubricating oil passage 13 until a fully opened state, from the state shown in
c) shows relationships between the pressure of oil ejected from the pump 1, the pressure of oil supplied to the valve timing control device 2, and the pressure of oil supplied to the main gallery 8 at that time. In the state (III) in
Incidentally, the valve timing control device 2 has, albeit only slightly, small gaps between constituent components. Thus, particularly when the oil viscosity is low, oil may leak (be exuded) from small gaps, and the oil pressure may not efficiently act on the valve timing control device 2. In order to actuate the valve timing control device 2 in such a case, it is necessary to increase the size of the pump 1, thereby increasing the ejection pressure from the pump 1. That is to say, a power for driving the pump 1 becomes necessary, and the fuel efficiency of the engine may be poor instead.
Accordingly, if the oil temperature further increases to become higher than a second set temperature T2 and the oil viscosity decreases, electricity is not fed to the OCV 5 (OFF), as shown in
Note that the second set temperature T2 is higher than the first set temperature T1. Furthermore, for example, the first set temperature T1 may be 55 to 65° C., and the second set temperature T2 may be 100 to 110° C., but the temperatures may be set at other values.
Next, a second embodiment of the oil pressure control apparatus according to the present invention will be described with reference to
As shown in
The thermosensor main body portion 42 is fixed to the valve body 33. The thermosensor accommodating member 41 is slidable between the valve body 33 and the thermosensor main body portion 42, but is always biased by a spring 43 toward the lubricating oil passage 13. The thermosensor main body portion 42 internally accommodates thermowax (not shown), and the thermowax is set so as to be expanded if the oil temperature becomes higher than the second set temperature T2. When the thermowax is expanded, as shown in
The side wall of the valve body 33 is provided with an oil supply passage 51 that is connected to the lubricating oil passage 13 and an operating oil passage 53 that supplies oil to the rear face of the second pressure receiving face 31b of the spool 31. Furthermore, the outer circumferential face of the thermosensor accommodating member 41 is provided with a ring-shaped oil passage 52. If the oil temperature is lower than the second set temperature T2, as shown in
As shown in
Hereinafter, an operation of the oil pressure control apparatus will be described with reference to the drawings. Note that “X”, “XI”, “XIII”, “XIV”, and “XV” in
Immediately after start of the engine, the oil temperature is low, and, thus, the oil viscosity is high, and an oil leak is small. Accordingly, although the amount of ejection from the pump 1 is small, the pressure of oil in the oil ejection passage 11A and the lubricating oil passage 13 is high. Accordingly, as shown in
b) shows relationships between the pressure of oil ejected from the pump 1, the pressure of oil supplied to the valve timing control device 2, and the pressure of oil supplied to the main gallery 8 in the state (X) in
When the warm-up progresses to some extent and the oil temperature is higher than the first set temperature T1, the oil viscosity decreases and the oil pressure decreases. Accordingly, as shown in
Subsequently, when the number of rotations of the engine increases and the pressure of oil ejected from the pump 1 increases, the pressure of oil in the lubricating oil passage 13 also increases, and the spool 31 gradually opens the lubricating oil passage 13 until a fully opened state as shown in
c) shows relationships between the pressure of oil ejected from the pump 1, the pressure of oil supplied to the valve timing control device 2, and the pressure of oil supplied to the main gallery 8 at that time. In the state (XI) in
In this manner, if the oil temperature is lower than the second set temperature T2, the spool 31 adjusts the flow passage area of the lubricating oil passage 13 depending only on the pressure level of oil in the lubricating oil passage 13.
If the oil temperature further increases to become higher than the second set temperature T2 and the oil viscosity excessively decreases, in the valve timing control device 2, oil leaks (is exuded) from small gaps between constituent components. However, as shown in
b) shows relationships between the pressure of ejected oil, the pressure of oil supplied to the valve timing control device 2, and the pressure of oil supplied to the main gallery 8 at that time. Since the lubricating oil passage 13 has been fully opened, the pressure of oil on the main gallery 8 and the pressure of oil on the valve timing control device 2 both follow a change in the pressure of oil ejected from the pump 1.
In summary, as shown in
Hereinafter, another embodiment of the thermosensor control portion 4 will be described with reference to
The thermosensor main body portion 42 is formed in an arrangement space 71 inside the body main body 33a of the valve body 33, and is placed and fixed to a placement face 33g forming a bottom face of the arrangement space 71. The thermosensor main body portion 42 has a cylindrical shape, and internally accommodates thermowax (not shown). The thermosensor main body portion 42 is provided with the movable member 42a that can be projected from and withdrawn into the thermosensor main body portion 42. When the thermowax is expanded and the movable member 42a is projected, the cup-shaped thermosensor accommodating member 41 provided so as to cover the thermosensor main body portion 42 moves upward in the drawings resisting the biasing force of the spring 43.
In this embodiment, even in a non-actuated state in which the movable member 42a has been withdrawn into the thermosensor main body portion 42 and the thermosensor accommodating member 41 has been moved by the biasing force of the spring 43 toward the placement face 33g to the extent possible, a clearance 72 is ensured between an end face 41a of the thermosensor accommodating member 41 and the placement face 33g. The body main body 33a of the valve body 33 is provided with the oil supply passage 51 that supplies oil from the lubricating oil passage 13 via the thermosensor control portion 4 to the rear face of the second pressure receiving face 31b of the spool 31 when the thermosensor control portion 4 is in an actuated state. The oil supply passage 51 branches in mid-course into a heat transmission oil passage 61 that is interconnected to the clearance 72.
If the oil temperature is lower than the second set temperature T2 and the thermosensor control portion 4 is in the non-actuated state, as shown in
In order to prevent the thermosensor accommodating member 41 from being moved by the pressure of oil supplied to the arrangement space 71 upward in the drawings and putting the thermosensor control portion 4 in the actuated state regardless of the state in which the thermosensor control portion 4 has to be kept in the non-actuated state because the oil temperature is lower than the second set temperature T2, the thermosensor accommodating member 41 is provided with a through hole 41b. The oil supplied to the arrangement space 71 flows through a clearance between the thermosensor accommodating member 41 and the thermosensor main body portion 42 and the through hole 41b and is supplied also to a space that accommodates the spring 43. As a result, oil pressures act on the thermosensor accommodating member 41 from both sides and cancel each other, and, thus, the thermosensor accommodating member 41 can be prevented from being moved by the pressure of oil supplied to the arrangement space 71.
In this embodiment, the space that accommodates the spring 43 is sealed by a cover member 44. Furthermore, in order to suppress an oil leak through a gap between the body main body 33a of the valve body 33 and the cover member 44, a ring-shaped sealing member 45 that can be engaged with the body main body 33a is provided.
The body main body 33a of the valve body 33 is provided with, in addition to the oil supply passage 51 and the heat transmission oil passage 61, the operating oil passage 53 that supplies oil to the rear face of the second pressure receiving face 31b of the spool 31, an oil return passage 62 that returns oil from the arrangement space 71 to the downstream side in the lubricating oil passage 13, and a first oil discharge passage 57 and a second oil discharge passage 58 that expose oil to the atmosphere.
With respect to the oil supply passage 51 (or the heat transmission oil passage 61), in a planar view, the oil return passage 62 is positioned at 180 degrees from the oil supply passage 51, the operating oil passage 53 and the first oil discharge passage 57 are positioned at 90 degrees from the oil supply passage 51, and the second oil discharge passage 58 is positioned at 90 degrees in the opposite direction from the oil supply passage 51. Since the heat transmission oil passage 61 and the oil return passage 62 are positioned opposing each other at 180 degrees, the oil that flows from the heat transmission oil passage 61 via the clearance 72 into the arrangement space 71, and then flows out from the arrangement space 71 via the clearance 72 into the oil return passage 62 uniformly flows around the thermosensor main body portion 42, and, thus, heat can be evenly and uniformly transmitted to the thermowax.
The outer circumferential face of the thermosensor accommodating member 41 is provided with a first ring-shaped oil passage 59 that functions when supplying oil to the rear face of the second pressure receiving face 31b of the spool 31 and a second ring-shaped oil passage 60 that is connected to the first oil discharge passage 57. The first ring-shaped oil passage 59 is configured so as not to be interconnected to the oil supply passage 51 and the operating oil passage 53 when the thermosensor control portion 4 is in the non-actuated state (
With the thus configured oil passages, regardless of whether the thermosensor control portion 4 is in the non-actuated state or the actuated state, oil is supplied from the lubricating oil passage 13 via the heat transmission oil passage 61 and the clearance 72 to the arrangement space 71, and is returned from the arrangement space 71 via the clearance 72 and the oil return passage 62 to the lubricating oil passage 13. Furthermore, when the thermosensor control portion 4 is in the non-actuated state, oil that is present on the rear face of the second pressure receiving face 31b of the spool 31 is exposed to the atmosphere via the operating oil passage 53, the second ring-shaped oil passage 60, and the first oil discharge passage 57 (
In this embodiment, as shown in
As shown in
Note that, in this embodiment, the clearance 72 is configured so as to be formed over the entire circumference between the end face 41a of the thermosensor accommodating member 41 and the placement face 33g, but part of the end face 41a may be configured so as to be in contact with the placement face 33g as long as the interconnection between the heat transmission oil passage 61 and the oil return passage 62 is not blocked and the thermosensitive properties of the thermowax are not impaired. Furthermore, instead of providing the through hole 41b in the thermosensor accommodating member 41, or, in addition to providing the through hole 41b, it is also possible to increase the length of the oil supply passage 51 such that oil is directly supplied to the space that accommodates the spring 43. Furthermore, in a state in which the spool 31 has narrowed the lubricating oil passage 13 to a minimum, the flow passage space 34 and the downstream side in the lubricating oil passage 13 may be interconnected to each other.
(1) The foregoing embodiments showed the case in which the first predetermined portion is the valve timing control device 2 on the intake valve side, but there is no limitation to this. As the first predetermined portion, it is also possible to apply a valve timing control device on the exhaust valve side or oil supply portions such as a piston jet or a turbocharger.
(2) The foregoing embodiments showed the example in which the lock mechanism 27 locks the relative rotational phase at the most retarded phase, but there is no limitation to this. For example, it is also possible to apply a lock mechanism that locks the relative rotational phase at an intermediate phase between the most retarded phase and the most advanced phase or at the most advanced phase.
(3) The foregoing embodiments showed the lock mechanism 27 merely as an exemplary mechanism that locks the relative rotational phase. For example, it is also possible to apply a lock mechanism including a lock member that is projected and withdrawn along the axis X, or a lock mechanism in which one lock member corresponds to one lock groove. Moreover, it is also possible to apply a configuration in which the relative rotational phase is locked by pressing a vane against an end face of a fluid pressure chamber, without providing a lock mechanism.
(4) The foregoing embodiments showed the case in which the torsion spring 23 that biases the inner rotor 22 to the advance side is included, but there is no limitation to this. For example, it is also possible to include a torsion spring that biases the inner rotor 22 to the retard side.
(5) The foregoing embodiment showed the example in which the operating oil passage 14 is an oil passage that is branched from the retard oil passage 12B, but there is no limitation to this. For example, if the present invention is applied to a valve timing control device for the exhaust valve, if the lock mechanism locks the relative rotational phase at a phase other than the most retarded phase, if the relationship between a displacement force based on the cam torque variation and a biasing force of the torsion spring is changed, or if the method for cancelling the lock mechanism is changed, it is also possible to connect the operating oil passage 14 to the advance oil passage 12A. Furthermore, it is also conceivable to connect a retainer operating oil passage to both of the advance oil passage and the retard oil passage.
(6) The foregoing embodiments showed the example in which the retard control can be performed when electricity is fed to the OCV 5, and the advance control can be performed when the feeding of electricity is stopped, but there is no limitation to this. It is also possible to apply a configuration in which the advance control can be performed when electricity is fed to the OCV, and the retard control can be performed when the feeding of electricity is stopped.
(7) The foregoing embodiment showed the configuration in which the thermosensor control portion 4 is regulated so as to displace the spool 31 to fully open the lubricating oil passage 13 if the oil temperature becomes higher than the second set temperature T2, but there is no limitation to this. The degree of the lubricating oil passage 13 opened by the spool 31 may be set as appropriate as necessary.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-198790 | Sep 2010 | JP | national |
| 2010-282879 | Dec 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2011/061387 | 5/18/2011 | WO | 00 | 2/11/2013 |
