SYSTEM INCORPORATING THE SAME

BACKGROUND OF INVENTION

1. Field of Invention

[0001] The present invention relates generally to automotive camshaft phaser systems and, more specifically, to a coupler system for a camshaft phaser system.

2. Description of the Related Art

[0002] Conventional automotive variable valve timing systems known in the art typically include an internal combustion engine that has a crankshaft and one or more camshafts controlled by one or more camshaft phasers. Phasers are used to alter the timing of valve events so as to improve engine performance, fuel economy, and emissions. Phasers are typically operatively attached to an end of the camshaft and are also in rotational communication with the engine crankshaft, so as to either advance or retard the phase of the camshaft with respect to the crankshaft. Phasers can be actuated in a number of different ways, and have historically been controlled using servo-controlled hydraulic pressure. However, the recent trend in the art is to control phasers with electric motors, which can provide broader phase control and improved response time. The electric motor and phaser are operatively attached to each other and in rotational communication so as to allow rotation of the motor to adjust the phase angle of the camshaft. To that end, a coupling is typically used to operatively attach the electric motor to the phaser so as to simplify engine assembly and component installation.

[0003] Each of the components of a variable valve timing system of the type described above must cooperate to effectively translate rotation from the electric motor to the phaser. In addition, each of the components must be designed not only to facilitate improved performance and efficiency, but also so as to reduce the cost and complexity of manufacturing and assembling the phaser system. While camshaft phaser systems known in the related art have generally performed well for their intended purpose, there remains a need in the art for a camshaft phaser system that has superior operational characteristics, and, at the same time, reduces the cost and complexity of manufacturing the components of the system.

SUMMARY OF THE INVENTION

[0004] The present invention overcomes the disadvantages in the related art in a coupler system for interconnecting an electric motor to a phaser for controlling the phase between a camshaft and a crankshaft of an internal combustion engine. The coupler system includes a receiver operatively attached to the phaser, and a driver in rotational communication with the electric motor. The driver interfaces with the receiver so as to simultaneously translate rotation from the electric motor to the phaser and compensate for misalignment between the electric motor and the phaser.

[0005] In addition, the present invention is directed toward a system for controlling the phase between a camshaft and a crankshaft of an internal combustion engine. The system includes a phaser, an electric motor, and a driver. The phaser is operatively attached to the camshaft and in rotational communication with the crankshaft, is used to adjust the phase of the camshaft with respect to the crankshaft, and includes a receiver. The electric motor is in rotational communication with the phaser, and is used to actuate the phaser so as to control the phase of the camshaft. The driver is operatively attached to the electric motor and interfaces with the receiver so as to simultaneously translate rotation from the electric motor to the phaser and compensate for misalignment between the electric motor and the phaser. [0006] In this way, the present invention significantly reduces the complexity of aligning and attaching the electric motor to the phaser and compensates for any misalignment that may occur as a result of manufacturing tolerances or assembly procedure. Moreover, the present invention reduces the cost and complexity of manufacturing camshaft phaser systems that have superior operational characteristics, such as improved packaging size and increased control capability.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Other objects, features, and advantages of the present invention will be readily appreciated as the same becomes better understood after reading the subsequent description taken in connection with the accompanying drawing wherein:

[0008] Figure 1 is a partial exploded perspective view of an automotive engine showing a camshaft phaser, an electric motor, and a motor coupling according to one embodiment of the present invention.

[0009] Figure 2 is an enlarged perspective view of the motor coupling of Figure 1 showing a driver and a receiver in an assembled configuration.

[0010] Figure 3 is an exploded perspective view of the motor coupling of Figure 2.

[0011] Figure 4 is an enlarged perspective view of the receiver of Figure 2.

[0012] Figure 5 is an enl arged front pl an view of the receiver of Figure 3.

[0013] Figure 6 is a sectional view taken along line 6-6 of Figure 5.

[0014] Figure 7 is an enlarged perspective view of the driver of Figure 2.

[0015] Figure 8 is an enlarged left side plan view of the driver of Figure 7.

[0016] Figure 9 is an enlarged top plan view of the driver of Figure 8 in a first configuration, [0017] Figure 10 is an enlarged top plan view of the driver of Figure 9 in a second configuration.

[0018] Figure 11 is a sectional view taken along line 1 1.-11 of Figure 9.

[0019] Figure 12 is a sectional view taken along line 12-12 of Figure 8,

[0020] Figure 13 is an alternate sectional view of Figure 1 1 showing the driver and receiver in an assembled configuration.

DETAILED DESCRIPTION OF THE INVENTION

[0021] Referring now to the figures, where like numerals are used to designate like structure, a portion of an internal combustion engine of an automobile is illustrated at 20 in Figure 1. The engine 20 includes a block 22 and one or more cylinder heads 24 mounted to the block 22. A crankshaft 26 is rotatably supported in the block 22, and one or more camshafts 28 are rotatably supported in the cylinder head 24. The crankshaft 26 drives the camshafts 28 via a timing system, generally indicated at 30. The timing system 30 typically includes a chain, generically shown at 32 in Figure 1, which interconnects a crankshaft sprocket 34 to one or more camshaft sprockets 36 and phasers 38. The timing system 30 may also include a tension guide 40 to ensure proper tension of the chain 32 in operation. While the representative embodiment illustrated in Figure 1 depicts a chain 32 and sprockets 34, 36, those having ordinary skill in the art will appreciate that the timing system 30 could utilize any suitable configuration sufficient to drive the camshafts 28 with the crankshaft 26 without departing from the scope of the present example. By way of non-limiting example, a timing belt in conjunction with timing gears could be utilized.

[0022] The engine 20 generates rotational torque which is subsequently translated by the crankshaft 26 to the camshafts 28 which, in turn, actuate valves (not shown, but generally known in the art) in the cylinder head 24 for controlling the timing of the flow of intake and exhaust gasses. Specifically, the camshafts 28 control what is commonly referred to in the art as "valve events," whereby the camshaft 28 opens and closes intake and exhaust valves at specific time intervals with respect to the rotational position of the crankshaft 26, so as to effect a complete thermodynamic cycle of the engine 20.

[0023] Phasers 38 are typically operatively attached to an end of one or more camshafts 28 and are in rotational communication with the crankshaft 26. The phasers 28 are configured to adjust the phase of the camshaft 28 with respect to the crankshaft 26 so as to alter the timing of the valve events discussed above. To that end, the phasers typically include outer teeth 42 in communication with the timing chain 32, and an inner portion 44 in rotational communication with an actuator, such as an electric motor 46. The electric motor 46 is typically controlled by an electronic control unit (ECU) (not shown, but generally known in the art), which also controls the engine 20 ignition timing and fuel delivery. Those having ordinary skill in the art will appreciate that phasers 38 can be designed in a number of different ways and, thus, the phaser 38 could have any suitable configuration, or be of any type sufficient to alter the phase of the camshaft 28, as discussed above, without departing from the scope of the present invention. Moreover, it will be appreciated that the electric motor 48 could have any suitable design or configuration sufficient to actuate and be in rotational communication with the phaser 38, as discussed above, without departing from the scope of the present invention. Further, while the engine 20 illustrated in Figure 1 is a V- configured, dual-overhead-cam (DOHC), spark-ignition Otto-cycle engine, with phasers 38 on each intake camshaft 34, those having ordinary skill in the art will appreciate that the engine 20 could be of any suitable configuration, with any suitable number of camshafts 34 disposed in any suitable way, controlled using any suitable thermodynamic cycle, with any suitable number of phasers 38, without departing from the scope of the present invention. [0024] As shown in Figure 1, the electric motor 46 and the phaser 38 are interconnected by a coupler system, generally indicated at 48. The coupler system 48 of the present invention simultaneously translates rotation from the electric motor 48 to the phaser 38 and compensates for misalignment between the electric motor 48 and the phaser 38, as discussed in greater detail below.

[0025] Referring now to Figures 1-3, the coupler system 48 of the present invention includes a driver 50 that interfaces with a receiver 52 so as to translate rotation and compensate for misalignment, as discussed above. In the embodiment illustrated throughout the figures, the driver 50 is in rotational communication with the electric motor 46, and the receiver 42 is operatively attached the phaser 38. As discussed in greater detail below, while the coupler system 48 of the present invention is shown disposed between the phaser 38 and electric motor 46 for illustrative purposes (see Figure 1), those having ordinary skill in the art will appreciate that the driver 50 could be operatively attached to, formed with, or otherwise in rotational communication with the electric motor 46 in any suitable way without departing from the scope of the present invention. Similarly, it will be appreciated that the receiver 52 could be operatively attached to, formed with, or otherwise in rotational communication with the phaser 38 in any suitable way without departing from the scope of the present invention. Moreover, those having ordinary skill in the art will appreciate that the relationships described above could be re-arranged, wherein the receiver 52 could be attached to or formed with the electric motor 46, and wherein structural features of the driver 50 could be attached to or formed with the phaser 38.

[0026] Referring now to Figures 3 and 7, in one embodiment of the present invention, the driver 50 includes a drive puck 54 that cooperates with a slot 56 disposed in the receiver 52 to translate rotation and compensate for misalignment between the driver 50 and receiver 52, as discussed above. The drive puck 54 of the driver 50 is in rotational communication with the electric motor 46, whereby the drive puck 54 has a cross member 58 that engages the slot 56 of the receiver 52. As show best in Figure 3, the cross member 58 is aligned substantially perpendicular to a Z axis 59 defined by rotation of the receiver 52. The slot 56 of the receiver 52 is configured to accommodate the cross member 58 of the driver 50 therein, such that rotation is translated from the cross member 58 to the slot 56.

[0027] As shown best in Figures 3, 4, and 13, the drive puck 54 has a substantially cylindrical profile that cooperates with a bore 60 formed in the receiver 52, as discussed below. The bore 60 merges with slot 56 (see Figure 4), and is configured to accommodate at least a portion of the drive puck 54 in operation (see Figure 13). While the bore 60 and drive puck 54 illustrated throughout the figures both have cylindrical profiles, it will be appreciated that the bore 60 and drive puck 54 could have any suitable profile, shape, or configuration without departing from the scope of the present invention. Further, as shown best in Figures 4 and 6, the receiver 52 may include a keyslot 61 that merges with the cylindrical bore 60. The keyslot 61 may cooperate with a key (not shown, but known in the art), or some other securing feature, to rotatably align and secure the receiver 52 to the phaser 38. However, those having ordinary skill in the art will appreciate that the keyslot 61 could be omitted or configured differently without departing from the scope of the present invention.

[0028] Referring now to Figure 3, the cross member 58 opposing lateral ends 62 that define a first distance 64 therebetween. As shown, the cross member 58 has a cylindrical profile and may be press-fit into the drive puck 54. To that end, the drive puck 54 may include a tunnel 66 for accommodating the cross member 58 therein. However, those having ordinary skill in the art will appreciate that the cross member 58 could be configured, formed with, or operatively attached to the drive puck 54 in any suitable way without departing from the scope of the present invention. By way of non-limiting example, it is conceivable that the drive puck 54 and cross member 58 could be formed or otherwise manufactured as a single, integral component. Moreover, it is conceivable that the cross member 58 could be defined by a pair of pins (not show, but generally known in the art) operatively attached to the drive puck 54. Referring now to Figures 4, 7, and 13, the slot 56 of the receiver 52 defines a second distance 68 therealong (see Figure 5). In one embodiment, the second distance 68 of the slot 56 is greater in magnitude than the first distance 64 of the cross member 58 of the drive puck 54 of the driver 50. Those having ordinary skill in the art will appreciate that this arrangement allows the cross member 58 to translate along the slot 56 so as to compensate for misalignment between the electric motor 46 and the phaser 38.

[0029] Referring now to Figures 3-6 and 8, in one embodiment, the cross member 58 has a first diameter 70 and the slot 56 has a width 72 (see Figure 4) that is substantially equal in magnitude to the first diameter 70. It will be appreciated that this arrangement provides secure engagement between the driver 50 and receiver 52 so as to translate rotation from the electric motor 46 to the phaser 38. Moreover, in one embodiment, the slot 56 has a depth 74 that is greater in magnitude than the first diameter 70 of the cross member 58. It will be appreciated that this arrangement allows the cross member 58 to translate along the Z axis 59 in operation, thereby enabling compensation for misalignment between the electric motor 46 and the phaser 38. However, those having ordinary skill in the art will appreciate that the first diameter 70 of the cross member 58, as well as the width 72 and depth 74 of the slot 56, could individually be configured in any suitable way without departing from the scope of the present invention.

[0030] In one embodiment, the driver 50 also includes a drive member 76 operatively attached to the electric motor 46 and in rotational communication with the drive puck 54, as described in greater detail below. The drive member 76 includes a plurality of radially spaced drive pins 78 extending therefrom. As shown best in Figures 3 and 12, the drive pins 78 are formed as separate components and may be pressed into cylindrical recesses 80 defined in the drive member 76. However, those having ordinary skill in the art will appreciate that the that the drive pins 78 could be operatively attached to or otherwise formed with the drive member 76 in any suitable way without departing from the scope of the present invention. The drive pins 78 have a second diameter 82 and cooperate with the drive puck 54 as described below. As shown best in Figures 3 and 12, the drive puck 54 includes a plurality of radially spaced apertures 84 for accommodating the drive pins 78 of the drive member 76. The apertures 84 of the drive puck 54 have a third diameter 86 that is greater in magnitude than the second diameter 82 of the drive pins 78 of the drive member 76. It will be appreciated that this arrangement allows the drive puck 54 to pivot with respect to and about the Z axis 59 (compare Figures 9 and 10), so as to compensate for misalignment between the electric motor 46 and the phaser 38 in operation.

[0031] While the coupler system 48 of the present invention incorporates a pair of drive pins 78 and a respective pair of apertures 84 of the drive puck 54, those having ordinary skill in the art will appreciate that any suitable number of radially spaced drive pins 78 and apertures 84 could be utilized, sufficient to cooperate so as to allow the drive puck 54 to pivot as described above, without departing from the scope of the present invention.

[0032] As shown in Figures 3, 7, and 12, in one embodiment, the drive pins 78 of the drive member 76 have terminal ends 88 that face away from the drive member 76. The driver 50 may further include at least one retaining member 90 operatively attached adjacent to the terminal ends 88, and at least one pair of thrust members 92, described in greater detail below. As shown best in Figures 7 and 12, the retaining member 90 is a pair of e-clips that are attached to grooves 94 formed in the drive pins 78 adjacent to the terminal ends 88. However, those having ordinary skill in the art will appreciate that any suitable number retaining members 90 of any suitable configuration could be utilized without departing from the scope of the present invention. Referring now to Figures 3 and 12, the thrust members 92 are spaced from each other along the drive pins 78, and the drive puck 54 is disposed between the thrust members 92. The thrust members 92 are formed as disks that have through-holes 96, which are spaced so as to cooperate with the drive pins 78 of the drive member 76. It will be appreciated that this arrangement limits movement of the thrust members 92 and the drive puck 54 along the drive pins 78, and that the thrust members 92 effectively space the drive puck 54 from and prevent engagement of both the drive member 76 and the retaining member 90. Moreover, to that end, the drive puck 54 may be formed from a first material having a first hardness, and the thrust members 92 may be formed from a second material having a second hardness, with the first hardness being greater than the second hardness. However, those having ordinary skill in the art will appreciate that the various components of the coupler system 48 described herein could be manufactured from any suitable material or materials with any suitable properties without departing from the scope of the present invention.

[0033] Referring now to Figure 9, in one embodiment, a gap 98 is defined between the retaining member 90 and the drive member 76. The drive puck 54 has a first thickness 100 defined along the drive pins 78. Similarly, the retaining members 90 have a second thickness 102 defined along the drive pins 78. The gap 98 is greater in magnitude than the sum of the thicknesses 100, 102 of the drive puck 54 and the retaining members 90. It will be appreciated that this arrangement allows the drive puck 54 to pivot with respect to the Z-axis 59, as described above (see Figure 10).

[0034] In this way, the coupler system 48 of the present invention significantly reduces the complexity of aligning and attaching the electric motor 46 to the phaser 38 and, at the same time compensates for any misalignment that may occur as a result of manufacturing tolerances or assembly procedure. Specifically, it will be appreciated that the features of the driver 50 and receiver 52 discussed above cooperate to provide secure and reliable engagement between the electric motor 46 and phaser 38 and, ultimately, reduce the cost and complexity of manufacturing variable valve timing systems.

[0035] The invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.