HYDRAULIC ACTUATION PIN SYSTEM

Abstract

Hydraulic actuating pin system comprising: an actuating pin (202) having a proximal end and a distal end; a clutch drum (210) having a grooved rim (212) extending circumferentially over a surface of the clutch drum (210), the grooved rim (212) having a plurality of raised portions (216) separated by a plurality of depressed portions (214), the raised portions (216) extending away from the surface of the clutch drum (210) over the depressed portions (214); a spring (204) which urges the actuating pin (202) towards the grooved ring (212) of the clutch drum (210), wherein the actuating pin (202), when it extends into the grooved ring (212), prevents rotation of the clutch drum (210) by preventing one of the raised portions (216) of the grooved ring (212) from to rotate freely under the actuating pin (202); a hydraulic input (320) providing hydraulic pressure to compress the spring (204) and extend the actuating pin (202) from the clutch drum (210) and over the raised portion (216) of the fluted rim (212) to allow the clutch drum (210) to rotate without interference from the actuating pin (202), wherein the fluted rim (212) has three raised portions (216) and three depressed portions (214), each having substantially equal circumferential lengths, such that the clutch drum (210) can rotate approximately 60° when the actuating pin (202) extends into one of the depressed portions (214) and can rotate up to 120° when the actuating pin (202) encounters one of the raised portions (216) and then rotates the length of the raised section (216) before extending into an adjacent lowered section (214).

Description

The present invention relates generally to the field of motorized machines, and more particularly to a system embodied as a hydraulic detent pin system for controlling the rotation of a clutch drum upon startup of an engine.In coupling an apparatus to a machine, the apparatus to be driven by an output shaft of the machine, it is desirable at start-up that the output shaft of the machine be free to rotate about 60 degrees for coupling the apparatus, but be free to rotate no more than 180 degrees from the starting point. Under certain conditions, it may be difficult for the output shaft of the engine to operate within these parameters. These parameters may vary for different machines and / or devices.An example condition in which it is difficult for the engine motor driving the output shaft to operate within the above parameters is at a cold start (for example, -30° C. or below). In some systems, a brake driven by a liquid pump is used to prevent the output shaft from rotating more than 180 degrees during start-up. To apply the brake, the liquid pump pulls liquid up from a reservoir through a channel. During cold start conditions, the fluid may be very viscous and the fluid pump may take several seconds to build up brake pressure to draw the highly viscous fluid up through the channel and activate the brake system. Thus, it may take several seconds to fill the braking volume and brake the output shaft running since the startup.One approach to this problem is to uniformly space three pins about the axis of the coupling line. However, the output shaft may break these pins if the fluid pressure suddenly drops. Another disadvantage of this solution is that the piston and brake cone interface may be steel-to-steel, which has an unfavourable wear behaviour and generates undesired heat. An alternative construction is to use a steel piston and a brake cone with ball rollers instead of pins. In this alternative, the balls may wedge and produce flats, resulting in cyclic failure in the ball and ramp construction. The usual disadvantages in these "free" rotation solutions and braking problems are: (1) whether ball or pin, both fail at sudden pressure loss, (2) steel-to-steel structures wear rapidly, (3) the amount of brake pressure applied to the output shaft is only that of the disk springs with which the piston is forced back, and high device inertia may take minutes to leak, with the risk of the pins being broken if the steel-to-steel interface fails, and (4) the "free rotation" for coupling the device is not truly free because the clutch disk springs exert constant pressure on the thrust bearing.In addition, different parking lock devices are known from the field of motor vehicles. Thus, DE 10 2006 046 712 A1 discloses a parking lock device for a motor vehicle, in which a parking lock gear has an external toothing into which a pawl can be positively brought into engagement in order to fix a drive shaft connected to the parking lock gear and to secure the motor vehicle against rolling away. Furthermore, U.S. Pat. No. 6,250,433 B1 discloses a parking brake for a work vehicle, in which a pin of complementary shape can be engaged into an external toothing of a toothed disk drive-connected to associated vehicle wheels, so that a rotation of the toothed disk can be blocked. In both cases, the aim is to exclude any unexpected or undesired movements of the vehicle in question.What would be desirable would be a system that allows limited rotation of an engine output shaft to couple a device to the output shaft while preventing complete rotation of the output shaft. Further, it would be desirable if such a system were operating under all conditions including extreme cold and if such a system could be easily stopped in the event of failure, such as loss of hydraulic pressure.A hydraulic actuation pin system is disclosed that includes an actuation pin, a clutch drum, a spring, and a hydraulic input. The actuating pin has a proximal and a distal end. The clutch drum has a fluted collar extending circumferentially across a surface of the clutch drum, the fluted collar having a plurality of raised portions separated by a plurality of lowered portions, the raised portions extending across the lowered portions away from the surface of the clutch drum. The spring urges the actuating pin toward the fluted ring of the clutch drum, and when the actuating pin extends into the lowered portion of the fluted ring, the actuating pin prevents rotation of the clutch drum by preventing one of the raised portions of the fluted ring from freely rotating below the actuating pin. The hydraulic input provides hydraulic pressure to compress the spring and pull the actuating pin out of the clutch drum and over the raised portion of the fluted collar to allow the clutch drum to rotate without interference from the actuating pin, the fluted collar having three raised portions and three lowered portions each having substantially equal circumferential lengths such that the clutch drum can rotate about 60° when the actuating pin extends into one of the lowered portions and can rotate up to 120° when the actuating pin encounters one of the raised portions and can then continue to rotate the length of the raised portion before extending into an adjacent lowered portion.The proximal end of the actuation pin may have a head, and the hydraulic pressure may move the head of the actuation pin to compress the spring and pull the actuation pin out of the clutch drum. The spring may be coupled to the head of the actuation pin. The distal end of the actuating pin may have a distal surface, and when the actuating pin extends completely into the recessed portion of the recessed collar of the clutch drum, the distal surface of the actuating pin may not contact the bottom in the recessed portion of the recessed collar of the clutch drum. FIG. 1 shows an example hydraulic actuation pin system coupled to the front end of an engine motor; FIG. 2 is a close-up view of an example hydraulic actuation pin system including the clutch drum; FIG. 3 is a cross-sectional view of a portion of an exemplary hydraulic actuating pin system including the actuating pin and its extension into a lower portion of the clutch drum; FIG. 4 shows an example embodiment of a clutch drum for use with a hydraulic actuation pin system; and FIG. 5 shows a schematic illustration of an example hydraulic circuit for an example hydraulic actuation pin system.Reference will be made to the embodiments described herein and illustrated in the drawings, wherein the same are described with a specific language.FIG. 1 shows an example embodiment of a front end 100 of a machine engine having a hydraulic actuation pin system 102, and FIG. 2 shows a schematic close-up view of an example embodiment of the hydraulic actuation pin system 102. The example system 102 includes an actuation pin 202, a spring 204, a plug 206, and a clutch drum 210. FIG. 4 shows the example clutch drum 210 itself. The example clutch drum 210 includes a fluted collar 212 having three depressed portions 214 extending circumferentially, separated by three raised portions 216. The depressed portions 214 may be substantially planar with the surface of the clutch drum 210, wherein the raised portions 216 protrude above the surface of the clutch drum 210; or the depressed portions 214 may be below the surface of the clutch drum 210, wherein the raised portions 216 are substantially planar with the surface of the clutch drum 210; or the depressed portions 214 and the raised portions 216 may be above and / or below the surface of the clutch drum 210, wherein the depressed portions 214 are relatively lower than the raised portions 216. In the example clutch drum 210 of FIGS. 2 and 4, the depressed portions 214 and the raised portions 216 are above the surface of the clutch drum 210, with the depressed portions 214 being relatively lower than the raised portions 216. In the embodiment of FIG. 4, the depressed portions 214 and raised portions 216 have substantially equal circumferential lengths, whereby the clutch drum can rotate about 60° when the actuating pin 102 extends into one of the depressed portions 214, and can rotate up to 120° when the actuating pin 102 encounters one of the raised portions 216 and then continues to rotate about the length of the raised portion before extending into an adjacent depressed portion 214. The clutch drum 210 may include more or less raised and lowered portions 214, 216, depending on which amount of rotation is desired when the actuating pin 202 is engaged / extended.FIG. 3 shows a cross-section of the actuation pin system 102 along with a system hydraulic line 320. The actuating pin 202 has a distal surface 302 and a proximal head 304 at the distal and proximal ends of the actuating pin 202, respectively. The actuating pin 202 is positioned to extend to and retract from the fluted collar 212 of the clutch drum 210.The actuation pin 202 is controlled by a hydraulic system using a hydraulic line 320. When no hydraulic pressure is applied, the spring 204 is not compressed and pushes the actuating pin 202 toward the clutch drum 210, and when the actuating pin 202 extends into one of the lowered portions 214, it prevents the clutch drum 210 from moving beyond the ends of the lowered portion 214 into which the actuating pin 202 is extended. The system may be configured such that the distal surface 302 of the actuation pin 202 does not contact the clutch drum 210 in the lowered portion 214 when the actuation pin 202 extends into one of the lowered portions 214. In operation, the hydraulic pressure introduced via the hydraulic line 320 enters a retraction region 224 and presses against the proximal head 304 of the actuation pin 202 to compress the spring 204 and move the actuation pin 202 away from the clutch drum 210, out of the lowered portion 214, and over the raised portions 216, such that the clutch drum 210 is free to rotate.FIG. 5 shows a schematic illustration of an example embodiment of an actuation pin system and hydraulic circuit 500. Hydraulic circuit 500 includes a pump source 502 that provides hydraulic pressure to a brake system 504 and an actuation pin system 506. The hydraulic system 500 may also include a system pressure regulating valve 508 and an accumulator 516. The actuation pin system 506 includes a pin valve body 510 having a one-way flow valve 512 and a pressure relief port 514. When the hydraulic system 500 is not providing pressure, the spring 204 pushes the actuation pin 202 into one of the lowered portions 214 of the clutch drum 210, allowing only limited rotation of the clutch drum 210. When the hydraulic system is activated, the source 502 pumps fluid through the one-way flow valve 512 via the hydraulic line 320 and into the retraction region 224 below the proximal head 304 of the actuating pin 202. When the hydraulic system 500 also includes the accumulator 516, the source 502 of the activated hydraulic system also pumps fluid through the one-way flow valve 512 and into the accumulator 516 via the hydraulic line 320. As hydraulic pressure in the retraction region 224 increases, the proximal head 304 of the actuation pin 202 compresses the spring 204 and retracts the actuation pin 202 from the clutch drum 210 and over the raised portions 216 to allow free rotation of the clutch drum 210. System pressure from source 502 acts on actuation pin 202 and retracts actuation pin 202 from the surface of clutch plate 210 to allow clutch drum 210 to freely rotate. FIG. 5 also shows a leakage path 520 back to the sump if the hydraulic fluid leaks out around the head 304 of the actuation pin 202.Should a loss of system pressure occur for some reasons, the actuating pin 202 remains pulled out of the clutch drum 210 and slowly returns toward the clutch drum 210 under the control of the pressure relief port 514. Should the hydraulic pressure cease, the hydraulic fluid in the retraction region 224 and the accumulator 516 (if present) will return through the hydraulic line 320 bypassing the one-way valve 512 via the pressure relief port 514. This allows the spring 204 to relax and urge the actuation pin 202 into one of the lowered portions 214 of the clutch drum 210. The pressure relief port 514 and the reservoir 516 may be configured to control the re-insertion speed of the actuation pin 202 into the clutch drum 210.The actuating pin 202 may be constructed such that the distal surface 306 does not contact the bottom of the lowered portions 214 of the clutch drum 210 when the actuating pin 202 is fully extended, thereby providing for true free rotation of the clutch drum 210 within the limits set by the lowered portions 214.Depending on which movement of the clutch drum 210 is desired when the actuation pin 202 is extended, there may be more or less than three depressed portions and raised portions. Additionally or alternatively, the circumferential lengths of the depressed portions and raised portions may be configured to control the movement of the clutch drum 210 when the actuation pin 202 is extended.

Claims

A hydraulic actuating pin system comprising: an actuating pin (202) having proximal and distal ends; a clutch drum (210) having a fluted collar (212) extending circumferentially across a surface of the clutch drum (210), the fluted collar (212) having a plurality of raised portions (216) separated by a plurality of lowered portions (214), the raised portions (216) extending away from the surface of the clutch drum (210) across the lowered portions (214); a spring (204) urging the actuating pin (202) toward the fluted collar (212) of the clutch drum (210), the actuating pin (202), when extended into that of the fluted collar (212), preventing rotation of the clutch drum (210) by preventing one of the raised portions (216) of the fluted collar (212) from freely rotating under the actuating pin (202); a hydraulic input (320) providing hydraulic pressure to compress the spring (204) and withdraw the actuating pin (202) from the clutch drum (210) and over the raised portion (216) of the fluted collar (212) to allow the clutch drum (210) to rotate without interference from the actuating pin (202), wherein the fluted collar (212) has three raised portions (216) and three lowered portions (214) each having substantially equal circumferential lengths such that the clutch drum (210) can rotate about 60° as the actuating pin (202) extends into one of the lowered portions (214) and can rotate up to 120° as the actuating pin (202) encounters one of the raised portions (216) and then can continue to rotate about the length of the raised portion (216) before extending into an adjacent lowered portion (214).The hydraulic actuation pin system of claim 1, wherein the proximal end of the actuation pin (202) has a head and the hydraulic pressure moves the head of the actuation pin (202) to compress the spring (204) and pull the actuation pin (202) out of the clutch drum (210).The hydraulic actuation pin system of claim 1 or 2, wherein the spring (204) is coupled to the head of the actuation pin (202).The hydraulic actuating pin system of any one of claims 1 to 3, wherein the distal end of the actuating pin (202) has a distal surface, and when the actuating pin (202) extends fully within the lowered portion (214) of the fluted ring (212) of the clutch drum (210), the distal surface of the actuating pin (202) does not contact the bottom of the lowered portion (214) of the fluted ring (212) of the clutch drum (210).The hydraulic actuator pin system of any of claims 1 to 4, wherein the hydraulic system comprises: a pump source (502) that controls the provision of hydraulic pressure; and a one-way flow valve (512) between the pump source (502) and the actuator pin (202), wherein the one-way flow valve (512) permits flow from the pump source (502) to the actuator pin (202) and blocks flow from the actuator pin (202) to the pump source (502).The hydraulic actuator pin system of claim 5, wherein the hydraulic system further comprises a pressure relief port (514) parallel to the one-way flow valve (512), and the pressure relief port (514) allows for controlled relief of hydraulic pressure from the actuator pin (202).The hydraulic actuator pin system of claim 5 or 6, wherein the hydraulic system further comprises an accumulator (516) hydraulically coupled to the actuator pin (202), the one-way flow valve (512) permits flow from the pump source (502) to the actuator pin (202) and to the accumulator (516), and the pressure relief port (514) permits controlled relief of hydraulic pressure from the actuator pin (202) and the accumulator (516).The hydraulic operating pin system according to any one of claims 5 to 7, wherein the proximal end of the operating pin (202) has a proximal head, and the hydraulic pressure supplied to the operating pin (202) presses against the proximal head of the operating pin (202) to compress the spring (204) and pull out the operating pin (202) from the clutch drum (210).

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