Pressure accumulating device

Abstract

To provide a pressure accumulating device without a need of always conducting electricity during pressure accumulation by miniaturizing a system with no pump.SOLUTION: A pressure accumulating device 100 has: a plunger 120 arranged inside a coil 110; a first rolling element 134 arranged between a first taper ring 132 arranged on an inner periphery of the plunger and a shaft 10; a second rolling element 144 arranged between a second taper ring 142 mounted to a housing 102 and the shaft; a first retainer 150 and a second retainer 160, through which the shaft is inserted and which disengage the first and second rolling elements; a pressure chamber 206 varying its capacity by a piston 204 coupled with the shaft; a spring chamber 208 contacting the piston and housing a return spring 210 energizing the shaft in a direction for reducing the capacity of the pressure chamber; and a suction valve 222a and a discharge valve 222b arranged on a suction port 214a and a discharge port 214b provided in the pressure chamber, and limiting flows in discharge and suction directions.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pressure accumulator device provided with an electromagnetic actuator.

Background Art

[0002] A vehicle is equipped with a pressure accumulator device that functions as a hydraulic source, for example. Patent Document 1 describes a piston-type accumulator (pressure accumulator device). This pressure accumulator device includes a pressure chamber, a piston, a detent mechanism (return prevention mechanism) for preventing the return of the piston, a spring, and an armature (plunger), and functions as a hydraulic source during idling stop. Oil is supplied to the pressure chamber by a pump.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the pressure accumulator device of Patent Document 1, when starting after the engine stops, a pump for supplying the clutch engagement hydraulic pressure for operating the clutch is required, so there is a problem that the system becomes large-sized. Also, power supply is always required during pressure accumulation, resulting in an increase in power consumption.

[0005] In view of such problems, an object of the present invention is to provide a pressure accumulator device that eliminates the need for a pump to downsize the system and further does not require constant power supply during pressure accumulation.

Means for Solving the Problems

[0006] To solve the above problems, a typical configuration of the accumulator according to the present invention is an accumulator including an electromagnetic actuator and a pressure section. The electromagnetic actuator includes a coil that winds around a shaft, a plunger disposed inside the coil, a first taper ring disposed on the inner circumference of the plunger, a first rolling element disposed between the first taper ring and the shaft, a second taper ring attached to the housing, a second rolling element disposed between the second taper ring and the shaft, a first retainer that passes through the shaft and releases the engagement of the first rolling element in the first taper ring, and a second retainer that passes through the shaft and releases the engagement of the second rolling element in the second taper ring. The pressure section includes a piston connected to the shaft, a pressure chamber whose volume varies by the piston, and a spring chamber partitioned by the piston. The spring chamber accommodates a return spring that passes through the shaft and abuts against the piston to bias the shaft in a direction in which the volume of the pressure chamber decreases. The pressure section also includes an intake port and a discharge port provided in the pressure chamber, an intake side check valve disposed at the intake port to restrict the flow in the discharge direction, and a discharge side check valve disposed at the discharge port to restrict the flow in the intake direction. When a current within a predetermined range flows through the coil, the plunger and the first retainer are attracted. When a current greater than the predetermined range flows through the coil, the second retainer is further attracted.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide an accumulator that eliminates the need for a pump, downsizes the system, and does not require continuous energization during energy storage.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to omit duplicate explanations, and elements not directly related to the present invention are not shown.

[0010] FIG. 1 is an overall configuration diagram of an accumulator device 100 in an embodiment of the present invention. The accumulator device 100 includes an electromagnetic actuator 101 and a pressure unit 200, and functions as a hydraulic pressure source, for example, when the vehicle is idling and stopped. However, the accumulator device 100 is not limited to a hydraulic pressure source and also functions as a pressure source using other fluids (for example, air).

[0011] The electromagnetic actuator 101 is an actuator that feeds out the shaft 10. The electromagnetic actuator 101 has a cylindrical housing 102 and housing covers 104a and 104b attached to both sides of the housing 102. Inside the housing 102, the shaft 10 is inserted, and a coil 110 is wound around the shaft 10. In the figure, the state when the coil 110 is in a non-excited state (non-energized) in the accumulator 100 is shown, and the shaft 10 is located at the initial position.

[0012] The pressure section 200 has a function of sucking oil from a tank (not shown) and discharging high-pressure oil to a clutch or the like. The pressure section 200 has a case 202, a piston 204, a pressure chamber 206 (see FIG. 6), and a spring chamber 208. The case 202 is attached to the housing cover 104b of the electromagnetic actuator 101. The piston 204 is connected to the end 10a of the shaft 10 and partitions the spring chamber 208 together with the case 202 and the housing cover 104b.

[0013] Also, as shown in FIG. 6, the pressure chamber 206 is partitioned by the case 202 and the piston 204, and its volume varies with the movement of the piston 204. A return spring 210 is accommodated in the spring chamber 208 as shown in FIG. 1. The return spring 210 passes through the shaft 10 as shown in the figure and abuts against the piston 204 and the housing cover 104b, and biases the shaft 10 connected to the piston 204 in the direction in which the volume of the pressure chamber 206 decreases, that is, the side opposite to the shaft feed side shown in FIG. 1.

[0014] The pressure chamber 206 has a wall portion 212 facing the piston 204. An intake port 214a and a discharge port 214b are provided in the wall portion 212. The intake port 214a communicates with the pressure chamber 206 (see FIG. 6) through an opening 216a and further communicates with the outside (such as a tank storing oil) through an opening 218a. The discharge port 214b communicates with the pressure chamber 206 through an opening 216b and further communicates with the outside (such as a clutch) through an opening 218b.

[0015] In the suction port 214a, a suction-side check valve (suction valve 222a) is arranged together with a spring 220a. The suction valve 222a is a check valve supported by the spring 220a. The suction valve 222a is biased by the spring 220a to close the opening 218a as shown in FIG. 1, thereby restricting the flow in the discharge direction from the pressure chamber 206 to the outside.

[0016] In the discharge port 214b, a discharge-side check valve (discharge valve 222b) is arranged together with a spring 220b. The discharge valve 222b is a check valve supported by the spring 220b. The discharge valve 222b is biased by the spring 220b to close the opening 216b as shown in FIG. 1, thereby restricting the flow in the suction direction from the outside to the pressure chamber 206.

[0017] Inside the housing 102 of the electromagnetic actuator 101, a plunger 120 (also referred to as a movable iron core) is arranged inside the coil 110. On the inner periphery of the plunger 120, a first tapered ring 132 having a tapered shape with a diameter increasing toward the shaft feed side is arranged. Between the first tapered ring 132 and the shaft 10, a first rolling element 134 that engages with the first tapered ring 132 is arranged. The first rolling element 134 is a roller or a ball arranged in a direction perpendicular to the axis of the shaft 10. By the wedge action due to the engagement of these first tapered ring 132 and the first rolling element 134, a feed mechanism for feeding the shaft 10 to the feed side is constituted.

[0018] Also, a second tapered ring 142 having a tapered shape that widens in diameter toward the shaft feed side is attached to the housing cover 104b attached to the housing 102. A second rolling element 144 that engages with the second tapered ring 142 is disposed between the second tapered ring 142 and the shaft 10. The second rolling element 144 is a roller or a ball disposed in a direction perpendicular to the axis of the shaft 10. By the wedging action due to the engagement of these second tapered ring 142 and second rolling element 144, a return prevention mechanism is configured to prevent the return of the shaft 10 fed out to the feed side.

[0019] A first retainer 150 that holds the first rolling element 134 is inserted through the shaft 10. By this first retainer 150, the engagement of the first rolling element 134 in the first tapered ring 132 is released. Also, a second retainer 160 that holds the second rolling element 144 is inserted through the shaft 10. By this second retainer 160, the engagement of the second rolling element 144 in the second tapered ring 142 is released. Thereby, a release mechanism is configured to release the above-described return prevention mechanism. Also, a spring 162 is inserted through the second retainer 160. The second retainer 160 is biased by the spring 162 to the side opposite to the shaft feed side.

[0020] A first fixed core 170 is disposed between the above-described first retainer 150 and the housing cover 104a. Also, a second fixed core 180 is disposed between the coil 110 and the second retainer 160. Both the first fixed core 170 and the second fixed core 180 are cylindrical magnetic bodies. Note that the second fixed core 180 is a part of the housing 102.

[0021] The operation of the pressure accumulator 100 will be described below. FIG. 2 is a diagram showing an enlarged part of the pressure accumulator 100 in FIG. 1. In the non-excited state where no current is flowing through the coil 110, the shaft 10 is biased in the direction opposite to the shaft feed direction by the biasing force of the return spring 210 (see FIG. 1) housed in the spring chamber 208 of the pressure section 200. The first retainer 150 is inserted through the shaft 10 and biased in the direction opposite to the shaft feed direction by a spring 108 disposed within the first fixed core 170.

[0022] The positions shown in FIGS. 1 and 2 are the initial positions of the shaft 10 and the first retainer 150. At this time, the first rolling element 134 is engaged with the first tapering 132, and the second rolling element 144 is engaged with the second tapering 142.

[0023] FIG. 3 is a diagram for explaining the state in which the coil 110 is excited with a "weak current I1 (see FIG. 5) within a predetermined range" in the pressure accumulator 100 of FIG. 1. When sending out the shaft 10, a current within a predetermined range I1 is passed through the coil 110. As a result, as shown in FIG. 3, a first magnetic path M1 is formed in the coil 110 (the first magnetic path M1 will be described later).

[0024] When the first magnetic path M1 is formed, against the biasing force of the return spring 210 of the pressure section 200, the plunger 120 is attracted to the first fixed core 170, and the plunger 120 moves in the shaft feed direction. Then, since the first retainer 150 moves by being pushed by the plunger 120 and the wedging action due to the engagement of the first tapering 132 and the first rolling element 134 is effective, the shaft 10 is sent out in the feed direction as shown by the arrow A in FIG. 3.

[0025] FIG. 4 is a diagram for explaining the step operation of the pressure accumulator 100 following FIG. 3. After the plunger 120 and the first retainer 150 move as shown in FIG. 3 to send out the shaft 10, the first retainer 150 further moves as shown in FIG. 4. Due to the movement of this first retainer 150 and the biasing force of the spring 152 inserted through the first retainer 150, the engagement between the first tapering 132 and the first rolling element 134 is released (feeding mechanism). As a result, the shaft 10 is fed out by one step. At this time, since the second rolling element 144 is engaged with the second tapering 142, the return prevention mechanism that prevents the return of the shaft 10 fed out to the feeding side functions.

[0026] Here, after sending out the shaft 10 as described above, the first retainer 150 further moves to release the engagement of the first rolling element 134 between the plunger 120 and the shaft 10. Therefore, the moving amount of the first retainer 150 is larger than the moving amount of the plunger 120.

[0027] FIG. 5 is a diagram for explaining the current flowing through the coil 110 of the pressure accumulator 100 in the embodiment of the present invention, showing the waveform of the current with respect to time. When sending out the shaft 10 as described above, a current in a predetermined range I1 is passed through the coil 110. Thereby, the electromagnetic actuator 101 operates as described in FIGS. 2 - 4, and the shaft 10 is sent out.

[0028] The first magnetic field M1 formed when a current in the predetermined range I1 is passed through the coil passes through the first retainer 150, the first fixed core 170, the housing 102, the second fixed core 180, and the plunger 120 as shown in FIG. 4. That is, the first magnetic field M1 does not pass through the second retainer 160. Therefore, when the first magnetic field M1 is formed, such a magnetic field does not affect the second retainer 160.

[0029] As shown in Fig. 5, when the current flowing through the predetermined range I1 is stopped, since the engagement of the first rolling element 134 is released, the plunger 120 and the first retainer 150 perform operations opposite to those in Figs. 2-4, and the first retainer 150 returns to its initial position. At this time, for the shaft 10, the return prevention mechanism by the second rolling element 144 and the second taper ring 142 functions. That is, since the wedging action by the engagement of the second taper ring 142 and the second rolling element 144 is effective, the position of the shaft 10 does not return.

[0030] Therefore, by intermittently flowing a current in the predetermined range I1 through the coil 110 (pulse current), the electromagnetic actuator 101 repeats the operations in Figs. 2-4, and the shaft 10 is fed out by an arbitrary number of steps. In this way, the electromagnetic actuator 101 can perform a step operation of pulling in the shaft 10 by a predetermined amount each time.

[0031] Fig. 6 is an overall configuration diagram of the accumulator 100 after performing the step operation. In the accumulator 100, by performing a step operation of pulling in the shaft 10 by a predetermined amount by the electromagnetic actuator 101, the piston 204 connected to the shaft 10 in the pressure section 200 is also pulled in by a predetermined amount. As a result, in the pressure section 200, as shown in Fig. 6, the volume of the pressure chamber 206 increases and the pressure in the pressure chamber 206 decreases.

[0032] For this reason, the intake valve 222a receives the negative pressure generated in the pressure chamber 206 through the opening 216a. The spring constant of the spring 220a is appropriately set so that the spring 220a elastically deforms when the negative pressure acts on the intake valve 222a. Therefore, the intake valve 222a moves toward the pressure chamber 206 upon receiving the negative pressure and opens the opening 218a.

[0033] As a result, in the pressure section 200, for example, oil from the tank flows into the pressure chamber 206 through the opening 218a, the suction port 214a, and the opening 216a along the suction direction indicated by the arrow B. At this time, the discharge valve 222b closes the opening 216b and restricts the flow in the suction direction. In this way, in the accumulator 100, by intermittently flowing a current I1 within a predetermined range through the coil 110, oil can be sucked into and held in the pressure chamber 206.

[0034] FIG. 7 is a diagram for explaining a state in which the coil 110 is excited with a strong current greater than a predetermined range following the step operation of the accumulator 100 in FIG. 4. When returning the shaft 10, a current I2 (see FIG. 5) greater than the "predetermined range" shown in FIG. 5 is passed through the coil 110. As a result, as shown in FIG. 7, a second magnetic path M2 is formed. This second magnetic path M2 passes through the first retainer 150, the first fixed core 170, the housing 102, the second retainer 160, the second fixed core 180, and the plunger 120.

[0035] As described above, when the second magnetic path M2 passes through the second retainer 160, the second retainer 160 moves in the shaft feed direction against the biasing force of the spring 162 inserted into the second retainer 160. As a result, as shown in FIG. 7, the engagement of the second rolling element 144 in the second taper 142 is released, and a release mechanism for releasing the return prevention mechanism functions. Then, the shaft 10 moves in the direction opposite to the shaft feed side as shown by the arrow C in FIG. 7 by the return spring 210 of the pressure section 200 and returns to the initial position (see FIG. 8).

[0036] Here, the reason why the magnetic path M2 passes not only through the second fixed core 180 but also through the second retainer 160 is that since the magnetic flux generated by the large current I2 is large, the magnetic flux density becomes over-dense with only the second fixed core 180.

[0037] In particular, in the electromagnetic actuator 101, as shown in FIG. 7, in the second fixed core 180, a throttle portion 182 that reduces the cross section of the magnetic path flowing through the second fixed core 180 is provided on the surface facing the second retainer 160.

[0038] That is, when a current I1 within a predetermined range flows through the coil 110, the throttle portion 182 does not saturate magnetically. Therefore, in the first magnetic path M1, the magnetic flux mainly flows through the second fixed core 180. On the other hand, when a current I2 larger than the predetermined range flows through the coil 110, the throttle portion 182 saturates magnetically. Therefore, in the second magnetic path M2, the magnetic flux easily flows through the second fixed core 180 and the second retainer 160. By providing the throttle portion 182 on the surface of the second fixed core 180 facing the second retainer 160 in this way, it is possible to surely cause the magnetic flux to flow through the second retainer 160, and it becomes possible to surely make the release mechanism function.

[0039] As described above, according to the electromagnetic actuator 101, when a current I1 within a predetermined range flows through the coil 110, the plunger 120 and the first retainer 150 are attracted and operate, and the shaft 10 moves toward the feed side. On the other hand, when a current I2 within a predetermined range flows through the coil 110, the plunger 120 and the first retainer 150 are attracted, and further, when the second retainer 160 is also attracted and moves, the return prevention mechanism is released. For this reason, the shaft 10 moves toward the side opposite to the shaft feed side and returns to the initial position.

[0040] Thus, in the electromagnetic actuator 101, by selecting a current I1 within a predetermined range or a current I2 larger than it to flow through the coil 110, the magnetic field of the coil 110 can be switched, and the shaft 10 can be moved in both directions. At this time, in the conventional actuator, a release coil (release solenoid) for releasing the lock mechanism and its accompanying components were required, whereas in the electromagnetic actuator 101, both the drive mechanism and the release mechanism can be made to function by one coil 110 and one electric circuit. Therefore, it becomes possible to further reduce the size and cost of the electromagnetic actuator 101.

[0041] FIG. 8 is an overall configuration diagram of the accumulator 100 in a state where the shaft 10 has returned to the initial position following FIG. 7. In the accumulator 100, when the shaft 10 returns to the initial position, the piston 204 connected to the shaft 10 also returns to the initial position as shown in FIG. 8. As a result, in the pressure section 200, the volume of the pressure chamber 206 decreases, and the pressure in the pressure chamber 206 increases.

[0042] For this reason, the discharge valve 222b receives the high-pressure oil in the pressure chamber 206 through the opening 216b. The spring constant of the spring 220b is appropriately set so that the spring 220b elastically deforms when the high-pressure oil acts on the discharge valve 222b. For this reason, the discharge valve 222b moves toward the outside when receiving the high-pressure oil and opens the opening 216b.

[0043] As a result, the pressure section 200 discharges the high-pressure oil held in the pressure chamber 206 to the outside (for example, the clutch) through the opening 216b, the discharge port 214b, and the opening 218b along the discharge direction indicated by the arrow D. At this time, the intake valve 222a closes the opening 218a and restricts the flow in the discharge direction.

[0044] In this way, the accumulator 100 can function as a hydraulic pressure source, and furthermore, oil is supplied to the pressure chamber 206 by a tank instead of a pump. Therefore, according to the accumulator 100, it is possible to reduce the cost by making the system smaller by eliminating the need for a pump. Furthermore, since it is not necessary to constantly energize during pressure accumulation, the power consumption can be reduced.

[0045] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings. Needless to say, the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that those also belong to the technical scope of the present invention.

Industrial Applicability

[0046] The present invention can be used as an accumulator provided with an electromagnetic actuator.

Description of Symbols

[0047] 10…Shaft, 100…Accumulator, 101…Electromagnetic actuator, 102…Housing, 104a, 104b…Housing cover, 106…Return spring, 108…Spring, 110…Coil, 120…Plunger, 132…First tapering, 134…First rolling element, 142…Second tapering, 144…Second rolling element, 150…First retainer, 152…Spring, 160…Second retainer, 162…Spring, 170…First fixed core, 180…Second fixed core, 182…Throttle portion, 200…Pressure portion, 202…Case, 204…Piston, 206…Pressure chamber, 208…Spring chamber, 210…Return spring, 212…Wall portion of pressure chamber, 214a…Suction port, 214b…Discharge port, 216a, 216b, 218a, 218b…Openings, 220a, 220b…Springs, 222a…Suction valve, 222b…Discharge valve

Claims

【Claim 1】 A pressure accumulator comprising an electromagnetic actuator and a pressure section, wherein the electromagnetic actuator comprises a coil that winds around the shaft, a plunger disposed inside the coil, a first tapered ring disposed on the inner periphery of the plunger, a first rolling element disposed between the first tapered ring and the shaft, a second tapered ring attached to the housing, a second rolling element disposed between the second tapered ring and the shaft, a first retainer that passes through the shaft and releases the engagement of the first rolling element in the first tapered ring, and a second retainer that passes through the shaft and releases the engagement of the second rolling element in the second tapered ring, wherein the pressure section comprises a piston connected to the shaft, a pressure chamber whose volume varies by the piston, a spring chamber partitioned by the piston, which houses a return spring that passes through the shaft and abuts against the piston to bias the shaft in a direction in which the volume of the pressure chamber decreases, an intake port and a discharge port provided in the pressure chamber, an intake-side check valve disposed in the intake port to restrict the flow in the discharge direction, and a discharge-side check valve disposed in the discharge port to restrict the flow in the intake direction, wherein when a current within a predetermined range flows through the coil, the plunger and the first retainer are attracted, and when a current greater than the predetermined range flows through the coil, the second retainer is further attracted. A pressure accumulator characterized by this.

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