Engine starting apparatus

• US 9,938,950 B2
• Filed: 04/06/2015
• Issued: 04/10/2018
• Est. Priority Date: 04/04/2014
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Okada, Tarou, Murata, Mitsuhiro
• Primary Examiner(s): Vo, Hieu T
• Assistant Examiner(s): MANLEY, SHERMAN D
• Application Number:
  US14/679,445
• Publication Number:
  US 20150316017A1
• Time in Patent Office: 1,100 Days
• CPC Class Codes: F02N 11/0851 characterised by means for controlling the engagement or disengagement between engine and starter, e.g. meshing of pinion and engine gear
• CPC Class Codes: F02N 11/087 Details of the switching means in starting circuits, e.g. relays or electronic switches
• CPC Class Codes: F02N 15/023 of the overrunning type
• CPC Class Codes: F02N 15/067 the starter comprising an electro-magnetically actuated lever
• CPC Class Codes: H02K 3/12 arranged in slots
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02K 7/116 with gears

Abstract

An apparatus for starting an engine, including a motor, an output shaft driven by the motor, a pinion provided along the output shaft, and an electro-magnetic solenoid device. The electro-magnetic solenoid device is configured to push the pinion axially toward a ring gear of the engine to mesh the pinion with the ring gear and transfer a rotational force, which is referred to as a motor torque, generated by energization of the motor from the pinion to the ring gear, thereby starting the engine. The apparatus is configured such that, at starting of the engine in its warmed-up state, the motor torque can continue to be applied from the pinion to the ring gear until at least the second compression stroke even when an engine speed varies.

Claims

1. An apparatus for starting an engine, comprising:

a motor;

an output shaft driven by the motor;

a pinion provided along the output shaft;

an electro-magnetic solenoid device configured to push the pinion axially toward a ring gear of the engine to mesh the pinion with the ring gear and transfer a rotational force generated by energization of the motor from the pinion to the ring gear, thereby starting the engine, the rotational force being referred to as a motor torque; and

rotation constraining means for constraining rotation of the pinion, the rotation constraining means being configured to constrain the rotation of the pinion at least from when the pinion abuts the ring gear to when the pinion meshes with the ring gear,

wherein, at starting of the engine in its warmed-up state, the motor torque can continue to be applied from the pinion to the ring gear until at least the second compression stroke even when an engine speed varies,

wherein the rotation constraining means comprises current constraining means for constraining activation current of the motor, thereby constraining, the rotation of the pinion,

wherein the current constraining means comprises at least one resistor,

wherein the apparatus further comprises;

a first switch configured to close and open a first energization path for energizing the motor, the first energization path passing through the at least one resistor;

a second switch configured to close and open a second energization path for energizing the motor, the second energization path bypassing the at least one resistor;

a second coil for generating an electromagnetic force to close the first switch; and

a first coil for generating an electromagnetic force to close the second switch in combination with the electromagnetic force generated by the second coil, and

wherein the electro-magnetic solenoid device is configured to close the first switch at starting of the engine, and close the second switch after closing the first switch.

2. The apparatus of claim 1, wherein the at least one resistor is carbon-based.

3. The apparatus of claim 1, wherein the first coil is supplied with excitation current via the first switch after the first switch being closed by energization of the second coil.

4. The apparatus of claim 3, wherein the first coil and the second coil are placed in a single frame.

5. The apparatus of claim 1, wherein the first coil and the second coil are arranged axially in parallel with each other.

6. The apparatus of claim 1, wherein the electro-magnetic solenoid device comprises a first plunger that is axially movable on an inner periphery of the first coil, and a second plunger that is axially movable on an inner periphery of the second coil, the first and second plungers being connected to be movable integrally with each other,

the first switch comprises a pair of first stationary contacts electrically connected along the first energization path and arranged to be axially movable a predetermined distance, and a first movable contact for connecting and disconnecting between the pair of first stationary contacts in conjunction with movement of the first plunger,

the second switch comprises a pair of second stationary contacts electrically connected along the second energization path, and a second movable contact for connecting and disconnecting between the pair of second stationary contacts in conjunction with movement of the second plunger,

the first movable contact and the second movable contact together form a single contact member, and

a distance between the pair of first stationary contacts and the first movable contact is set less than a distance between the pair of second stationary contacts and the second movable contact.

7. The apparatus of claim 6, wherein

the electro-magnetic solenoid device further comprises contact springs for urging the respective stationary contacts against the first movable contact, and drive springs for storing reaction forces to mesh the pinion with the ring gear, and

plunger attraction force generated by energization of the second coil is less than a set load of the contact spring or the drive spring.

8. The apparatus of claim 6, wherein each of the pair of first stationary contacts comprises the resistor.

9. The apparatus of claim 1, wherein the pinion is helical-splined to an outer periphery of the output shaft driven by the motor so that the pinion can be axially pushed alone toward the ring gear by operation of the electro-magnetic solenoid device.

10. The apparatus of claim 9, further comprising a one-way clutch disposed between an armature axis of the motor and the output shaft.