Information
-
Patent Grant
-
6668772
-
Patent Number
6,668,772
-
Date Filed
Tuesday, January 21, 200321 years ago
-
Date Issued
Tuesday, December 30, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Denion; Thomas
- Eshete; Zelalem
Agents
- Wenderoth, Lind & Ponack, L.L.P.
-
CPC
-
US Classifications
Field of Search
US
- 123 9011
- 251 1291
- 251 12919
- 251 12909
- 335 220
- 335 229
-
International Classifications
-
Abstract
When an inlet valve is opened or closed via a first mover, by the operation of a first linear actuator, energy accumulated by a first spring or a second spring is discharged by the operation of a second linear actuator, to transmit the energy to the inlet valve via a second mover and the first mover. As a result, the inlet valve can be opened or closed at a high speed, with higher energy efficiency and has an improved durability.
Description
BACKGROUND OF THE INVENTION
1) Field of the Invention
The present invention relates to improving the speed of linear reciprocating movement of a load, the energy efficiency, and durability of a liner actuator apparatus. The load is, for example, an inlet valve, an exhaust valve, or a fuel injection valve of an automobile gasoline engine.
2) Description of the Related Art
A prior art linear actuator apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-199411. This linear actuator apparatus is used as an actuating apparatus that linearly reciprocates to open or close the inlet valve or the exhaust valve of the automobile gasoline engine.
The configuration of this prior art linear actuator apparatus will be explained in detail below. The linear actuator has an actuating unit. The actuating unit includes a magnetic path member comprising a magnetic flux generator equipped with an electromagnetic coil by winding to generate a magnetic flux; and a magnetic field forming section that has at least two pole shoes to form at least one magnetic field region by distributing the magnetic flux. The linear actuator further has a magnetizing member fitted to a mover and having two magnetized surfaces having a different magnetic polarity from each other; an electric current supply unit that supplies a driving current having a magnetism corresponding to either the outward direction or the inward direction of the first mover, to the electromagnetic coil; and a valve stem and a valve element integral with the mover.
The linear actuator apparatus operates as explained below. When the current is not supplied to the electromagnetic coil, the valve element is located at a predetermined position (reference position). When a direct current flowing in a predetermined direction is supplied to the electromagnetic coil, the valve element moves in the predetermined direction and is located at an open position, corresponding to the size of the magnetic flux density. Further, when a direct current flowing in a direction opposite to the predetermined direction is supplied to the electromagnetic coil, the valve element moves in a direction opposite to the predetermined direction and is located at a closed position, corresponding to the size of the magnetic flux density.
SUMMARY OF THE INVENTION
The present invention relates to an improvement in the linear actuator apparatus.
The linear actuator apparatus, which linearly reciprocate a load, according to one aspect of the present invention has a first linear actuator including a first mover capable of linearly reciprocating in a first direction and a second direction, the first mover being connected to the load; a second linear actuator including a second mover capable of linearly reciprocating in the first direction and the second direction, the second mover being equipped with an accumulator; and a connecting unit that connects the first mover and the second mover so as to be able to move relative to each other linearly in the first direction and the second direction. The shift of the first mover is larger than that of the second mover. Moreover, the accumulator has a structure such that the accumulator accumulates energy by the shift of the second mover in one of the first direction and the second direction, and shifts the second mover in other one of the first direction and the second direction by discharging the accumulated energy, and the first mover and the second mover have an abutting surface, respectively, which abuts against each other when the accumulator accumulates or discharges energy, to thereby transmit energy to each other via the accumulator.
The linear actuator apparatus, which linearly reciprocate a load, according to an another aspect of the present invention has a first linear actuator including a first mover capable of linearly reciprocating in a first direction and a second direction, the first mover being connected to the load; a second linear actuator including a second mover capable of linearly reciprocating in the first direction and the second direction, the second mover being equipped with an accumulator; and a connecting unit that connects the first mover and the second mover so as to be able to move relative to each other linearly in the first direction and the second direction. The shift of the first mover is larger than that of the second mover. Moreover, the accumulator includes a first accumulator having a structure such that it accumulates energy by the shift of the second mover in the first direction due to the operation of the second linear actuator, and shifts the second mover in the second direction by discharging the energy accumulated by the operation of the second linear actuator; and a second accumulator having a structure such that it accumulates energy by the shift of the second mover in the second direction due to the operation of the second linear actuator, and shifts the second mover in the first direction by discharging the energy accumulated by the operation of the second linear actuator. In addition, the first mover and the second mover respectively include a first abutting surface that abuts against each other when the second mover shifts in the second direction due to the discharge of energy by the first accumulator, to transmit the energy discharged from the first accumulator to the load; and a second abutting surface that abuts against each other when the second mover shifts in the first direction due to the discharge of energy by the second accumulator, to transmit the energy discharged from the second accumulator to the load.
The actuating control method according to still another aspect of the present invention is realized on the linear actuator apparatuses according to the above-mentioned aspects of the present invention and comprises, at the time of startup, actuating the second linear actuator to shift the second mover in one of the first direction and the second direction and actuating the first linear actuator to shift the first mover in the same direction in which the second linear actuator is actuated.
The actuating control method according to still another aspect of the present invention is realized on the linear actuator apparatuses according to the above-mentioned aspects of the present invention and comprises damping the shift of the first mover by the action of the accumulator for accumulating the energy and by controlling the actuation of the second linear actuator.
These and other objects, features and advantages of the present invention are specifically set forth in or will become apparent from the following detailed descriptions of the invention when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a cross section of relevant parts of a linear actuator apparatus according to an embodiment of the present invention.
FIG. 2
is a cross section, in a different direction as compared to that of
FIG. 1
, of relevant parts of the linear actuator apparatus according to the present invention.
FIG. 3
is a cross section, in a different direction as compared to that of
FIG. 1
, of relevant parts of the linear actuator apparatus according to the present invention.
FIG. 4
is a cross section taken along line IV—IV in FIG.
3
.
FIG. 5
is a cross section that shows the initial state in FIG.
3
.
FIG. 6
is a cross section that shows the closed holding state in FIG.
3
.
FIG. 7
is a cross section that shows the open operation state in FIG.
3
.
FIG. 8
is a cross section that shows the open holding state in FIG.
3
.
FIG. 9
is a cross section that shows the closed operation state in FIG.
3
.
FIG. 10
is an explanatory diagram that shows the working waveform of a timing signal, charging of a first coil, charging of a second coil, target current of an electromagnetic coil, stroke of a second mover, and stroke of a first mover.
DETAILED DESCRIPTIONS
Exemplary embodiment(s) of the linear actuator apparatus and the actuating control method, according to the present invention, is explained, with reference to the accompanying drawings. The linear actuator apparatus according to this embodiment is used, for example, as an actuating apparatus that linearly reciprocates, that is, opens or closes an inlet valve of an automobile gasoline engine. However, the present invention is not limited to the embodiment.
FIGS. 1
to
10
shows the linear actuator apparatus according to the embodiment(s) of the present invention.
Explanation of Overall Structure
In
FIG. 1
, reference sign
1
denotes a cylinder head in an automobile gasoline engine. A combustion chamber
2
, an inlet path
3
, and an exhaust path
4
are respectively provided in the cylinder head
1
. An inlet port
5
is provided between the combustion chamber
2
and the inlet path
3
, and an exhaust port
6
is provided between the combustion chamber
2
and the exhaust path
4
.
An inlet valve
7
and an exhaust valve
8
are respectively equipped in the cylinder head
1
, so that opening and closing movement is possible. Further, the linear actuator apparatus
9
according to the embodiment and a cam mechanism
10
are also equipped in the cylinder head
1
, respectively.
The inlet valve
7
is connected to the linear actuator apparatus
9
. The inlet valve
7
shifts to open or close the inlet port
5
, by the actuating control of the linear actuator apparatus
9
. In other words, the inlet valve
7
is a direct-acting valve, whose
1
opening and closing movement is directly controlled by the linear actuator apparatus
9
.
On the other hand, the exhaust valve
8
is connected to the cam mechanism
10
. The exhaust valve
8
opens and closes the exhaust port
6
by the opening and closing movement due to the rotation of a cam in the cam mechanism
10
. The cam mechanism
10
is constructed such that the cam rotates synchronously with the rotation of a crank-shaft (not shown) in the automobile gasoline engine.
The linear actuator apparatus
9
comprises a first linear actuator
11
, a second linear actuator
12
, and a connecting unit
13
. The first linear actuator
11
and the second linear actuator
12
are respectively a linear actuator of an electromagnet type.
Explanation of the First Linear Actuator
11
As the first linear actuator
11
, for example, one described in Japanese Patent Application Laid-Open No. 2000-199411 is used. As shown in FIG.
2
and
FIG. 3
, the first linear actuator
11
has a holder
14
. The holder
14
holds the first mover
15
so as to be able to linearly reciprocate, that is, so as to enable opening and closing movement. In the figure, “arrow open” indicates the opening direction, that is, the outward direction, and “arrow close” indicates the closing direction, that is, the inward direction.
Two fixed holes (through holes) are provided in the first mover
15
, with a space therebetween in the opening and closing direction. Two magnets
16
and
17
are respectively fixed to the two fixed holes. The both sides of the two magnets
16
and
17
are substantially on the same plane with the both sides of the first mover
15
. The both sides of the two magnets
16
and
17
are respectively formed by magnetization on two magnetized surfaces having a different polarity from each other. In other words, as shown in
FIG. 3
, the left magnetized surface of the first magnet
16
is magnetized in the N pole, the right magnetized surface of the first magnet
16
is magnetized in the S pole, the left magnetized surface of the second magnet
17
is magnetized in the S pole, and the right magnetized surface of the second magnet
17
is magnetized in the N pole.
A first yoke
18
in a C-shape, a core
19
, and a second yoke
20
in a plate form are respectively fixed on the holder
14
. The two magnets
16
and
17
in the first mover
15
are arranged so as to enable opening and closing movement, between the first yoke
18
, the core
19
, and the second yoke
20
, respectively.
Three pole shoes
21
,
22
, and
23
are respectively arranged on the both sides of the first yoke
18
and the core
19
, in the opening and closing direction of the first mover
15
. A current supply unit (not shown) is electrically connected to the electromagnetic coil
24
.
The core
19
forms a magnetic flux generator equipped with the electromagnetic coil
24
by winding to generate a magnetic flux. The vicinity of the pole shoes
21
and
23
, and the vicinity of the pole shoes
22
and
23
form two magnetic field regions. The first yoke
18
has at least two pole shoes (in this example, three pole shoes
21
,
22
,
23
), to distribute the magnetic flux, and constitutes a magnetic field forming section, which forms at least one (in this example, two) magnetic field region. The second yoke
20
constitutes a magnetic path member. The two magnets
16
and
17
constitute a magnetizing member provided corresponding to the two magnetic field regions.
Two inlet valves
7
as the load are connected to one end of the first mover
15
. The inlet valve
7
comprises a valve shaft
25
, and a valve element
26
formed integrally at one end of the valve shaft
25
. The other end of the valve shaft
25
is fixed to one end of the first mover
15
.
When the electric current is not supplied to the electromagnetic coil
24
, as shown in
FIG. 5
, the valve element
26
is located at a predetermined position (reference position, in the initial state). When a direct current flowing in a predetermined direction is supplied to the electromagnetic coil
24
, the valve element
26
moves in the opening direction, corresponding to the magnitude of the magnetic flux density. Further, when a direct current flowing in a direction opposite to the predetermined direction is supplied to the electromagnetic coil
24
, the valve element
26
moves in the closing direction, corresponding to the size of the magnetic flux density. The size of the direct current to be supplied is substantially in proportion to the size of a driving force at the time of shifting the first mover
15
(and the inlet valve
7
) so as to open or close.
Explanation of the Second Linear Actuator
12
As shown in FIG.
2
and
FIG. 3
, a second mover
27
is equipped in the second linear actuator
12
, so as to enable the opening and closing movement in the same direction as that of the first mover
15
. The second mover
27
comprises a rod
28
, and an armature
29
integrally formed with the rod
28
in the intermediate thereof.
The second linear actuator
12
comprises a first solenoid
30
and a second solenoid
31
. The first solenoid
30
comprises a first core
32
and a first coil
34
wound on the first core
32
, and the second solenoid
31
comprises a second core
33
and a second coil
35
wound on the second core
33
. The armature
29
of the second mover
27
is arranged between the first solenoid
30
and the second solenoid
31
, so as to enable the opening and closing movement.
The first solenoid
30
is excited by energizing the first coil
34
, to shift the second mover
27
(the first mover
15
and the inlet valve
7
) in the closing direction, and allows the second mover
27
(the first mover
15
and the inlet valve
7
) to be held at the shifted closing position. The first solenoid
30
is demagnetized by de-energizing the first coil
34
, to release the holding state of the second mover
27
(the first mover
15
and the inlet valve
7
) at the closing position.
On the other hand, the second solenoid
31
is excited by energizing the second coil
35
, to shift the second mover
27
(the first mover
15
and the inlet valve
7
) in the opening direction, and allows the second mover
27
(the first mover
15
and the inlet valve
7
) to be held at the shifted opening position. The second solenoid
31
is demagnetized by de-energizing the second coil
35
, to release the holding state of the second mover
27
(the first mover
15
and the inlet valve
7
) at the opening position.
An accumulator
36
is equipped on the second mover
27
. The accumulator
36
has a casing
37
having a hollow cylindrical shape with one end (lower end) being open, and the other end (upper end) being closed. The lower end of the casing
37
is fixed on the second core
33
. A middle casing
38
in a hollow cylindrical shape is fixed in the casing
37
, with the opposite ends being open. A partition board
39
is integrally formed in the intermediate of the middle casing
38
.
As shown in
FIG. 4
, the partition board
39
is provided with a cruciate hole
40
. On the other hand, a cruciate push plate
41
is fixed at one end of the rod
28
of the second mover
27
. The push plate
41
can pass through the hole
40
.
A first spring
42
as a first accumulator is arranged between the upper end of the casing
37
and the partition board
39
. A second spring
43
as a second accumulator is arranged between the second core
33
and the partition board
39
.
The first spring
42
is for accumulating energy by compression due to the shift of the second mover
27
(the first mover
15
and the inlet valve
7
) in the closing direction, and for shifting the second mover
27
(the first mover
15
and the inlet valve
7
) in the opening direction by discharging the energy by expansion. The second spring
43
is for accumulating energy by compression due to the shift of the second mover
27
(the first mover
15
and the inlet valve
7
) in the opening direction, and for shifting the second mover
27
(the first mover
15
and the inlet valve
7
) in the closing direction by discharging the energy by expansion.
The cross section of the wire of the first spring
42
and the second spring
43
is elliptic, as shown in
FIGS. 1
to
3
. The cross section of the wire of the springs
42
and
43
may be circular, as shown in
FIGS. 5
to
9
.
Explanation of the Connecting Unit
13
The other end of the first mover
15
and the other end of the first mover
27
are connected to each other via the connecting unit
13
, so as to be able to move relative to each other in the opening and closing direction. In other words, as shown in
FIG. 2
, an engagement hole
45
having a large inner size and a through groove
46
having a small inner size are respectively provided at the other end of the first mover
15
. An engagement protrusion
47
having a large external size and a penetrating portion
48
having a small external size are respectively provided at the other end of the rod
28
of the second mover
27
. The engagement protrusion
47
is engaged in the engagement hole
45
so as to be able to move in the opening and closing direction. Similarly, the penetrating portion
48
penetrates through the through groove
46
so as to be able to move in the opening and closing direction.
As shown in
FIGS. 5
to
9
, the first mover
15
can shift for opening and closing with respect to the holder
14
, between the position where first stoppers
49
and
50
abut against each other (see
FIG. 6
) and the position where second stoppers
51
and
52
abut against each other (see FIG.
8
). The second mover
27
can shift for opening and closing with respect to the second linear actuator
12
, between the position where the armature
29
abuts against the first solenoid
30
(see
FIG. 6
) and the position where the armature
29
abuts against the second solenoid
31
(see FIG.
8
).
The shift of the first mover
15
is a distance T
1
between the second stoppers
51
and
52
(see
FIG. 6
) in the state that the first stoppers
49
and
50
abut against each other, or a distance T
1
(see
FIG. 8
) between the first stoppers
49
and
50
(see
FIG. 6
) in the state that the second stoppers
51
and
52
abut against each other. The shift of the second mover
27
is a distance T
2
between the armature
29
and the second solenoid
31
(see
FIG. 6
) in the state that the armature
29
abuts against the first solenoid
30
, or a distance T
2
(see
FIG. 8
) between the armature
29
and the first solenoid
30
(see
FIG. 6
) in the state that the armature
29
abuts against the second solenoid
31
.
The shift T
1
of the first mover
15
is larger than the shift T
2
of the second mover
27
. In this example, the shift T
1
of the first mover
15
is 6 mm, and the shift T
2
of the second mover
27
is 4 mm. As a result, the other end of the first mover
15
and the other end of the second mover
27
can move relative to each other in the opening and closing direction in the connecting unit
13
, by a difference of the shifts T
1
−T
2
=2 mm.
The other end of the first mover
15
and the other end of the second mover
27
have, respectively, a first abutting surface
53
and a second abutting surface
54
. As shown, in
FIG. 7
, the first abutting surface
53
comprises one inner face (lower face) of the engagement hole
45
, and one side (lower face) of the engagement protrusion
47
. The second abutting surface
54
comprises, as shown in
FIG. 9
, the other inner face (upper face) of the engagement hole
45
, and the other side (upper face) of the engagement protrusion
47
.
The first abutting surface
53
, that is, the lower face of the engagement hole
45
and the lower face of the engagement protrusion
47
abut against each other, when the second mover
27
shifts in the opening direction due to discharge of the energy by the first spring
42
, to transmit the energy discharged by the first spring
42
to the inlet valve
7
. The second abutting surface
54
, that is, the upper face of the engagement hole
45
and the upper face of the engagement protrusion
47
abut against each other, when the second mover
27
shifts in the closing direction due to discharge of the energy by the second spring
43
, to transmit the energy discharged by the second spring
43
to the inlet valve
7
.
The linear actuator apparatus
9
according to the embodiment has such a configuration, and the operation thereof is explained with reference to
FIGS. 5
to
10
.
Explanation of the Initial State
The initial state is, as shown in FIG.
5
and
FIG. 10
, a state in which the electric current is not supplied to the first coil
34
and the second coil
35
, that is, in
FIG. 10
, (B) a state in which charging of electricity to the first coil
34
is OFF, and (C) charging of electricity to the second coil
35
is OFF. As a result, the first solenoid
30
and the second solenoid
31
are not magnetized, that is, in the state of being de-magnetized.
On the other hand, the upper and lower surfaces of the push plate
41
of the second mover
27
are respectively pressed by the first spring
42
and the second spring
43
, which have a uniform spring force. As a result, the armature
29
of the second mover
27
is located in the intermediate position between the first solenoid
30
and the second solenoid
31
. In other words, the armature
29
of the second mover
27
is located at a position where the stroke of the second mover
27
is 0, in
FIG. 10
(see (E)).
Further, the initial state is a state in which an electric current is not supplied to the electromagnetic coil
24
, that is, a state in which the target current of the electromagnetic coil
24
is 0 in
FIG. 10
(see (D)). As a result, the first mover
15
is located at a predetermined position, that is, at a position of +2 mm of the stroke of the first mover
15
in
FIG. 10
(see (F)). The valve element
26
of the inlet valve
7
integral with the first mover
15
is in a state of half open.
Further, the lower face of the engagement hole
45
of the first abutting surface
53
abuts against the lower face of the engagement protrusion
47
.
Explanation of Startup, Closing Operation, and Holding Closed State
At the time of startup, when the timing signal in
FIG. 10
(see (A)) is turned ON, the first coil
34
in the first solenoid
30
is energized. In other words, charging of electricity to the first coil
34
is turned ON. Further, the electromagnetic coil
24
is energized to the closed side. In other words, the target current of the electromagnetic coil
24
becomes negative.
As a result, as shown in
FIG. 6
, the first mover
15
shifts in the closing direction and stops, because the first stoppers
49
and
50
abut against each other. The second mover
27
also shifts in the closing direction and stops, because the first solenoid
30
absorbs the armature
29
. Further, the second mover
27
shifts in the closing direction so that the upper face of the push plate
41
presses the first spring
42
, and the first spring
42
is compressed to accumulate energy.
In other words, the stroke of the second mover
27
shifts from 0 to −2 (closing operation in FIG.
10
). Further, the stroke of the first mover
15
shifts from +2 to 0 (closing operation in FIG.
10
). As shown in
FIG. 6
, the valve element
26
closes the inlet port
5
.
When the closed state is obtained through the startup and the closing operation, the amount of electric current to be supplied to the electromagnetic coil
24
is reduced. In other words, the target current of the electromagnetic coil
24
is brought close from a negative value to 0. As a result, the first mover
15
is retained, and the state in which the valve element
26
closes the inlet port
5
is retained (holding closed state in FIG.
10
). In this closed state, the amount of electric current to be supplied to the electromagnetic coil
34
may be reduced than that at the time of startup (starting current), so as to hold the second mover
27
by this small current (holding current).
In the closed state, the inlet valve
7
can be lifted via the first mover
15
, by the distance 2 mm of the relative movement in the connecting unit
13
. As a result, the idling control method (Japanese Patent Application No. 2001-036795) can be executed.
Explanation of Opening Operation, Opening of Brake, and Holding Open State
When the timing signal is changed from ON to OFF, the opening operation shown in
FIG. 10
starts. In other words, charging of electricity to the first coil
34
is changed from ON to OFF. The compressed first spring
42
then expands, to discharge the accumulated energy. The energy is transmitted to the first mover
15
through the second mover
27
and the first abutting surface
53
. As a result, the first mover
15
is energized in the opening direction.
At the same time, the target current of the electromagnetic coil
24
is changed from a negative value close to 0 to a positive value. The second mover
27
and the first mover
15
then initially shift integrally in the opening direction (the opening operation in FIG.
10
). In other words, the stroke of the second mover
27
changes from −2 to 0, and the stroke of the first mover
15
changes from 0 to +2.
As shown in
FIG. 7
, when the lower face of the push plate
41
abuts against the second spring
43
, opening of brake in
FIG. 10
starts. That is, the target current of the electromagnetic coil
24
changes from positive to negative. Further, the lower face of the push plate
41
presses the second spring
43
, to compress the second spring
43
, so as to accumulate energy. The opening of brake starts to act, to decelerate the shift of the second mover
27
in the opening direction, so that the first mover
15
precedes the second mover
27
in the opening direction.
As a result, the lower face of the engagement hole
45
is away from the lower face of the engagement protrusion
47
, on the first abutting surface
53
. In other words, the stroke of the second mover
27
changes from 0 to +2, and the stroke of the first mover
15
changes from +2 to +6. In opening the brake, the target current of the electromagnetic coil
24
is changed from positive to negative.
The upper face of the engagement protrusion
47
of the decelerated second mover
27
then abuts against the upper face of the engagement hole
45
in the preceding first mover
15
. In other words, as shown in
FIG. 8
, the second abutting surface
54
abuts to fully open the inlet valve
7
. The first mover
15
stops due to abutting of the second stoppers
51
and
52
on each other. At this time, the second coil
35
is changed from OFF to ON. The amount of electric current to be supplied to the electromagnetic coil
24
is reduced. In other words, the target current of the electromagnetic coil
24
is changed from a negative value to a positive value close to 0.
As a result, the second solenoid
31
absorbs the lower face of the armature
29
, and the fully opened state of the inlet valve
7
is held (holding open state in FIG.
10
). The shift speed of the first mover
15
(inlet valve
7
) in the opening direction at the time of fully opening the inlet valve
7
can be adjusted, by adjusting the current to the second coil
35
.
Explanation of Closing Operation, Closing of Brake, and Holding Closed State
When the timing signal is changed from OFF to ON, the closing operation shown in
FIG. 10
starts. In other words, charging of electricity to the second coil
35
is changed from ON to OFF. The compressed second spring
43
then expands, to discharge the accumulated energy. The energy is transmitted to the first mover
15
through the second mover
27
and the second abutting surface
54
. As a result, the first mover
15
is energized in the closing direction.
At the same time, the target current of the electromagnetic coil
24
is changed from a positive value close to 0 to a negative value. The second mover
27
and the first mover
15
then initially shift integrally in the closing direction (the closing operation in FIG.
10
). In other words, the stroke of the second mover
27
changes from +2 to 0, and the stroke of the first mover
15
changes from +6 to +4.
As shown in
FIG. 9
, when the upper face of the push plate
41
abuts against the first spring
42
, closing of brake in
FIG. 10
starts. That is, the target current of the electromagnetic coil
24
changes from negative to positive. Further, the upper face of the push plate
41
presses the first spring
42
, to compress the first spring
42
, so as to accumulate energy. The closing of brake starts to act, to decelerate the shift of the second mover
27
in the closing direction, so that the first mover
15
precedes the second mover
27
in the closing direction.
As a result, the upper face of the engagement hole
45
is away from the upper face of the engagement protrusion
47
on the second abutting surface
54
. In other words, the stroke of the second mover
27
changes from 0 to −2, and the stroke of the first mover
15
changes from +4 to 0. In closing the brake, the target current of the electromagnetic coil
24
is changed from negative to positive.
The lower face of the engagement protrusion
47
of the decelerated second mover
27
then abuts against the lower face of the engagement hole
45
in the preceding first mover
15
. In other words, as shown in
FIG. 6
, the first abutting surface
53
abuts to fully close the inlet valve
7
. The first mover
15
stops due to abutting of the first stoppers
49
and
50
on each other. At this time, the first coil
34
is changed from OFF to ON. The amount of electric current to be supplied to the electromagnetic coil
24
is reduced. In other words, the target current of the electromagnetic coil
24
is changed from a negative value to a positive value close to 0.
As a result, the first solenoid
30
absorbs the upper face of the armature
29
, and the fully closed state of the inlet valve
7
is held (holding open state in FIG.
10
). The shift speed of the first mover
15
(inlet valve
7
) in the closing direction at the time of fully closing the inlet valve
7
can be adjusted, by adjusting the current to the first coil
34
.
Thereafter, the opening operation, opening of brake, holding open state, the closing operation, closing of brake, and holding closed state are repeated, to thereby open and close the inlet valve
7
based on the predetermined time. In the action, charging of the electricity to the first coil
34
is turned ON at the time of starting holding closed state, but as shown in the chain line in
FIG. 10
, it may be at the time of starting the closing operation. Further, charging of the electricity to the second coil
35
is turned ON at the time of starting holding open state, but as shown in the chain line in
FIG. 10
, it may be at the time of starting the opening operation.
Explanation of an Example Other Than the Embodiment
The embodiment explains a configuration that works at the time of shifting in the opposite directions, that is, at the time of shifting of the inlet valve
7
in the opening direction (outward direction) and at the time of shifting thereof in the closing direction (inward direction). However, it is not limited to this configuration. The configuration may be such that the linear actuator apparatus may work at the time of shifting only in one direction, that is, at the time of shifting the load in the opening direction (outward direction) or at the time of shifting thereof in the closing direction (inward direction). In this case, as the spring, either the first spring
42
or the second spring
43
is necessary. For example, when there is the upper first spring
42
, only a simple stopper instead of the lower second spring
43
can accelerate the shift of the inlet valve
7
in the opening direction, and can reduce the impact at the time of sitting of the inlet valve
7
.
It is mentioned above that the second linear actuator
12
comprises the first solenoid
30
and the second solenoid
31
, but it is not limited to this. The second linear actuator
12
may comprise a linear actuator other than the first solenoid
30
and the second solenoid
31
.
It is mentioned above that the first spring
42
and the second spring
43
function as the first accumulator and the second accumulator. However, the accumulators may be realized with components other than the springs. Further, it is mentioned above that the first spring
42
and the second spring
43
are compression springs, but the springs could be a tension spring.
It is mentioned above that the linear actuator apparatus described in Japanese Patent Application Laid-Open No. 2000-199411 is used as the first linear actuator
11
. However, a linear actuator apparatus other than the one described in Japanese Patent Application Laid-Open No. 2000-199411 may be used.
In the embodiment, the inlet valve
7
is used as the load, but in the present invention, the load may be one other than the inlet valve
7
, for example, an exhaust valve or a fuel injection valve of the engine, or the like.
As is obvious from the description, according to the present invention, the accumulator efficiently accumulates or discharges the kinetic energy of the first mover and the second mover, thereby enabling a shift of the load at a high speed. After the load has started the shift, it is not necessary to supply the electric current to the second linear actuator at all times, and hence an increase of the driving energy can be suppressed. Since the accumulator can use the accumulated energy for the buffer action, the durability of the linear actuator and the load can be improved. Further, since the first mover and the second mover are connected so as to enable a relative movement thereof, and the shift of the first mover is made larger than that of the second mover, the kinetic energy can be superposed when the first mover and the second mover start to shift. Therefore, such a shift of the mover is made possible that a single linear actuator cannot handle with regard to the speed of response. As a result, the linear reciprocating movement of the load can be accelerated, and there is the effect that a linear actuator apparatus and an actuating control method, which improve the energy efficiency and the durability, can be obtained.
Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art which fairly fall within the basic teaching herein set forth.
Claims
- 1. A linear actuator apparatus that linearly reciprocate a load, comprising:a first linear actuator including a first mover capable of linearly reciprocating in a first direction and a second direction, the first mover being connected to the load; a second linear actuator including a second mover capable of linearly reciprocating in the first direction and the second direction, the second mover being equipped with an accumulator; and a connecting unit that connects the first mover and the second mover so as to be able to move relative to each other linearly in the first direction and the second direction, wherein the shift of the first mover is larger than that of the second mover, the accumulator has a structure such that the accumulator accumulates energy by the shift of the second mover in one of the first direction and the second direction, and shifts the second mover in other one of the first direction and the second direction by discharging the accumulated energy, and the first mover and the second mover have an abutting surface, respectively, which abuts against each other when the accumulator accumulates or discharges energy, to thereby transmit energy to each other via the accumulator.
- 2. The linear actuator apparatus according to claim 1, wherein the second linear actuator is a solenoid that allows the second mover to shift in one direction and to be held in the shifted position, upon magnetization, and releases the held state of the second mover, upon demagnetization, andthe accumulator is a spring that accumulates energy by compression or expansion due to the shift of the second mover in one of the first direction and the second direction, and shifts the second mover in other one of the first direction and the second direction by discharging energy by expansion or compression.
- 3. The linear actuator apparatus according to claim 1, wherein the first linear actuator comprises:an actuating unit including a magnetic path member comprising a magnetic flux generator equipped with an electromagnetic coil by winding to generate a magnetic flux, and a magnetic field forming section having at least two pole shoes to form at least one magnetic field region by distributing the magnetic flux; a magnetizing member fitted to the first mover and having two magnetized surfaces having a different polarity from each other; and an electric current supply unit that supplies a driving current having a magnetism corresponding to the movement of the first mover in either the first direction or the second direction, to the electromagnetic coil.
- 4. The linear actuator apparatus according to claim 1, wherein the load is an inlet valve, an exhaust valve, or a fuel injection valve of an engine.
- 5. The linear actuator apparatus according to claim 1, wherein at the time of startup, when the second linear actuator is actuated to shift the second mover, the first linear actuator is actuated to also shift the first mover in the same direction.
- 6. The linear actuator apparatus according to claim 1, wherein the shift of the first mover is damped by the action of the accumulator for accumulating the energy and by controlling the actuation of the second linear actuator.
- 7. A linear actuator apparatus that linearly reciprocate a load, comprising:a first linear actuator including a first mover capable of linearly reciprocating in a first direction and a second direction, the first mover being connected to the load; a second linear actuator including a second mover capable of linearly reciprocating in the first direction and the second direction, the second mover being equipped with an accumulator; and a connecting unit that connects the first mover and the second mover so as to be able to move relative to each other linearly in the first direction and the second direction, wherein the shift of the first mover is larger than that of the second mover, the accumulator includes a first accumulator having a structure such that it accumulates energy by the shift of the second mover in the first direction due to the operation of the second linear actuator, and shifts the second mover in the second direction by discharging the energy accumulated by the operation of the second linear actuator; and a second accumulator having a structure such that it accumulates energy by the shift of the second mover in the second direction due to the operation of the second linear actuator, and shifts the second mover in the first direction by discharging the energy accumulated by the operation of the second linear actuator, and the first mover and the second mover respectively include a first abutting surface that abuts against each other when the second mover shifts in the second direction due to the discharge of energy by the first accumulator, to transmit the energy discharged from the first accumulator to the load; and a second abutting surface that abuts against each other when the second mover shifts in the first direction due to the discharge of energy by the second accumulator, to transmit the energy discharged from the second accumulator to the load.
- 8. The linear actuator apparatus according to claim 7, whereinthe second linear actuator comprises a first solenoid that allows the second mover to shift in the second direction and to be held in the shifted position, upon magnetization, and releases the held state of the second mover, upon demagnetization, and a second solenoid that allows the second mover to shift in the first direction and to be held in the shifted position, upon magnetization, and releases the held state of the second mover, upon demagnetization, and the first accumulator comprises a first spring that accumulates energy by compression due to the shift of the second mover in the second direction, and shifts the second mover in the first direction by discharging the energy by expansion, and the second accumulator comprises a second spring that accumulates energy by compression due to the shift of the second mover in the first direction, and shifts the second mover in the second direction by discharging the energy by expansion.
- 9. The linear actuator apparatus according to claim 7, wherein the first linear actuator comprises:an actuating unit including a magnetic path member comprising a magnetic flux generator equipped with an electromagnetic coil by winding to generate a magnetic flux, and a magnetic field forming section having at least two pole shoes to form at least one magnetic field region by distributing the magnetic flux; a magnetizing member fitted to the first mover and having two magnetized surfaces having a different polarity from each other; and an electric current supply unit that supplies a driving current having a magnetism corresponding to the movement of the first mover in either the first direction or the second direction, to the electromagnetic coil.
- 10. The linear actuator apparatus according to claim 7, wherein the load is an inlet valve, an exhaust valve, or a fuel injection valve of an engine.
- 11. The linear actuator apparatus according to claim 7, wherein at the time of startup, when the second linear actuator is actuated to shift the second mover, the first linear actuator is actuated to also shift the first mover in the same direction.
- 12. The linear actuator apparatus according to claim 7, wherein the shift of the first mover is damped by the action of the accumulator for accumulating the energy and by controlling the actuation of the second linear actuator.
- 13. An actuating control method of the linear actuator apparatus that linearly reciprocate a load, the linear actuator apparatus havinga first linear actuator including a first mover capable of linearly reciprocating in a first direction and a second direction, the first mover being connected to the load; a second linear actuator including a second mover capable of linearly reciprocating in the first direction and the second direction, the second mover being equipped with an accumulator; and a connecting unit that connects the first mover and the second mover so as to be able to move relative to each other linearly in the first direction and the second direction, wherein the shift of the first mover is larger than that of the second mover, the accumulator has a structure such that the accumulator accumulates energy by the shift of the second mover in one of the first direction and the second direction, and shifts the second mover in other one of the first direction and the second direction by discharging the accumulated energy, and the first mover and the second mover have an abutting surface, respectively, which abuts against each other when the accumulator accumulates or discharges energy, to thereby transmit energy to each other via the accumulator, the method comprising, at the time of startup, actuating the second linear actuator to shift the second mover in one of the first direction and the second direction and actuating the first linear actuator to shift the first mover in the same direction in which the second linear actuator is actuated.
- 14. An actuating control method of the linear actuator apparatus that linearly reciprocate a load, the linear actuator apparatus havinga first linear actuator including a first mover capable of linearly reciprocating in a first direction and a second direction, the first mover being connected to the load; a second linear actuator including a second mover capable of linearly reciprocating in the first direction and the second direction, the second mover being equipped with an accumulator; and a connecting unit that connects the first mover and the second mover so as to be able to move relative to each other linearly in the first direction and the second direction, wherein the shift of the first mover is larger than that of the second mover, the accumulator includes a first accumulator having a structure such that it accumulates energy by the shift of the second mover in the first direction due to the operation of the second linear actuator, and shifts the second mover in the second direction by discharging the energy accumulated by the operation of the second linear actuator; and a second accumulator having a structure such that it accumulates energy by the shift of the second mover in the second direction due to the operation of the second linear actuator, and shifts the second mover in the first direction by discharging the energy accumulated by the operation of the second linear actuator, and the first mover and the second mover respectively include a first abutting surface that abuts against each other when the second mover shifts in the second direction due to the discharge of energy by the first accumulator, to transmit the energy discharged from the first accumulator to the load; and a second abutting surface that abuts against each other when the second mover shifts in the first direction due to the discharge of energy by the second accumulator, to transmit the energy discharged from the second accumulator to the load, the method comprising, at the time of startup, actuating the second linear actuator to shift the second mover in one of the first direction and the second direction and actuating the first linear actuator to shift the first mover in the same direction in which the second linear actuator is actuated.
- 15. An actuating control method of the linear actuator apparatus that linearly reciprocate a load, the linear actuator apparatus havinga first linear actuator including a first mover capable of linearly reciprocating in a first direction and a second direction, the first mover being connected to the load; a second linear actuator including a second mover capable of linearly reciprocating in the first direction and the second direction, the second mover being equipped with an accumulator; and a connecting unit that connects the first mover and the second mover so as to be able to move relative to each other linearly in the first direction and the second direction, wherein the shift of the first mover is larger than that of the second mover, the accumulator has a structure such that the accumulator accumulates energy by the shift of the second mover in one of the first direction and the second direction, and shifts the second mover in other one of the first direction and the second direction by discharging the accumulated energy, and the first mover and the second mover have an abutting surface, respectively, which abuts against each other when the accumulator accumulates or discharges energy, to thereby transmit energy to each other via the accumulator, the method comprising damping the shift of the first mover by the action of the accumulator for accumulating the energy and by controlling the actuation of the second linear actuator.
- 16. An actuating control method of the linear actuator apparatus that linearly reciprocate a load, the linear actuator apparatus havinga first linear actuator including a first mover capable of linearly reciprocating in a first direction and a second direction, the first mover being connected to the load; a second linear actuator including a second mover capable of linearly reciprocating in the first direction and the second direction, the second mover being equipped with an accumulator; and a connecting unit that connects the first mover and the second mover so as to be able to move relative to each other linearly in the first direction and the second direction, wherein the shift of the first mover is larger than that of the second mover, the accumulator includes a first accumulator having a structure such that it accumulates energy by the shift of the second mover in the first direction due to the operation of the second linear actuator, and shifts the second mover in the second direction by discharging the energy accumulated by the operation of the second linear actuator; and a second accumulator having a structure such that it accumulates energy by the shift of the second mover in the second direction due to the operation of the second linear actuator, and shifts the second mover in the first direction by discharging the energy accumulated by the operation of the second linear actuator, and the first mover and the second mover respectively include a first abutting surface that abuts against each other when the second mover shifts in the second direction due to the discharge of energy by the first accumulator, to transmit the energy discharged from the first accumulator to the load; and a second abutting surface that abuts against each other when the second mover shifts in the first direction due to the discharge of energy by the second accumulator, to transmit the energy discharged from the second accumulator to the load, the method comprising damping the shift of the first mover by the action of the accumulator for accumulating the energy and by controlling the actuation of the second linear actuator.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2002-011884 |
Jan 2002 |
JP |
|
US Referenced Citations (5)
Number |
Name |
Date |
Kind |
5611303 |
Izuo |
Mar 1997 |
A |
5692463 |
Liang et al. |
Dec 1997 |
A |
5730091 |
Diehl et al. |
Mar 1998 |
A |
6003481 |
Pischinger et al. |
Dec 1999 |
A |
6349685 |
Kolmanovsky et al. |
Feb 2002 |
B1 |
Foreign Referenced Citations (6)
Number |
Date |
Country |
0569088 |
Nov 1993 |
EP |
1045116 |
Oct 2000 |
EP |
4-67005 |
Oct 1992 |
JP |
2000-199411 |
Jul 2000 |
JP |
02064960 |
Aug 2002 |
WO |
0237006 |
Oct 2002 |
WO |