INTEGRATION OF A CHAIN-TRACKED PARKING SYSTEM

Abstract

Parking mechanism arranged on an axle drive or primary drive of a vehicle to engage or disengage an output shaft (102) connected to the wheels of the vehicle, the parking mechanism comprising: a first sprocket (204) with sprocket teeth (205), wherein the first sprocket (204) is connected to the output shaft (102) for driving the wheels of the vehicle; a second sprocket (202) with sprocket teeth (203); an endless loop chain (285) which engages with the sprocket teeth (205) of the first sprocket (204) and the sprocket teeth (203) of the second sprocket (202), wherein the endless loop chain (285) comprises: a first inner member (265) comprising: a body (265a) with a posterior section (266) having a first flank (266a), a second flank (266b) and a flat surface (266c); a pair of teeth connected by a step section (269) opposite the posterior section (266); a pair of openings (267) between the pair of teeth and the posterior section (266); wherein the posterior section (266) extends laterally from the body (265a) and is opposite at least the step section (269), at least a part of the pair of teeth and at least a part of the openings (267); a second inner member (275), comprising: a body (275a) with a posterior section (276); a pair of teeth connected by a step section (277) opposite the posterior section (276); a pair of openings (278) between the pair of teeth and the posterior section (276); and wherein the first inner members (265) and the second inner members (275) are arranged in alternating nested rows in the transverse and longitudinal directions and are pivotably connected by connecting pins (282); Guide plates (270) arranged on the outermost sides of the endless loop chain (285) to receive and fix the connecting pins (282); a parking pawl (208) which is pivotably movable between an engaged position in which the parking pawl (208) engages in the laterally extending rear section (266) of the first inner links (265) of the endless loop chain (285) and an disengaged position in which the parking pawl (208) is released from the laterally extending rear section (266) of the first inner links (265) of the endless loop chain (285), wherein the parking pawl (208) comprises: a body (255) with a first end (208a), a second end (208b), a top surface (219) and a bottom surface (220) opposite the top surface (219); a multitude of alternating teeth (213, 214) and depressions (216, 217, 218) on the lower surface (220) between the first end (208a) and the second end (208b); and a roller (210) rotatably attached to the first end (208a) of the body (255); and a cam arrangement (200) to move the parking pawl (208) between the engaged position and the disengaged position.

Description

STATE OF THE ART

[0001] The present invention relates to a parking system, more precisely to a chain system on the axle drive or primary drive, which includes link features that can be used as a parking system and replace a conventional parking system consisting of an internal combustion engine, an electric motor or a combination (hybrid solution).

[0002] In gearbox applications, the parking system is typically a self-contained system that includes a parking pawl and a notched parking ring on the output shaft, as in Fig. 1 and Fig. 2 shown. Fig. Figures 1 and 2 show conventional parking systems, such as those published on Street Smart Transmission: Transmission Parking Pawl. Street Smart Transmission of Tampa Inc., Florida USA, November 2020. URL: https: / / streetsmarttransmission.com / transmission-parking-pawl / [accessed on October 7, 2024].

[0003] Fig. 1 and Fig. Figure 3 shows a conventional parking system in which the transmission parking pawl is in a retracted, parked position. Fig. Figure 2 shows the conventional parking system with the transmission parking pawl in a disengaged position. A metal ring 104 with a plurality of notches 105 is attached to the output shaft 102. Next to it is a transmission parking pawl 111, which is movable between an engaged and a disengaged position. The transmission parking pawl 111 has a projection 107 that can engage in one of the notches 105 of the metal ring 104. When the transmission parking pawl 111 engages in the notch 105 of the metal ring 104, the metal ring 104 can no longer move, and consequently, neither the output shaft 102 nor the drive gears connected to the output shaft 102 (not shown) can rotate. The transmission parking pawl 111 is pressed into the parking position by a cam 112 when the vehicle is parked. The cam 112 presses the transmission parking pawl 111 against the force of the spring 108 into the notch 105 in the metal ring 104.When the vehicle is not in park mode and the cam 112 is not engaged, the spring 108 tensions the transmission parking pawl 111 of the transmission, so that the projection 107 does not engage with the metal ring 104 and the drive wheels associated with the output shaft 102 can rotate freely.

[0004] Fig. Figure 3 shows another conventional parking system, which is to be understood as an internal prior art (see, e.g., BORGWARNER: EV Transmissions. 31-03 eGearDrive® Transverse Electric Drive Transmission. BorgWarner Inc., December 2022. URL: https: / / www.borgwarner.com / technologies / ev-transmissions [accessed on October 7, 2024]). In this conventional parking system, the parking pawl 126 engages in the metal ring 104 with a plurality of notches 105; however, the parking pawl 126 is engaged by a cam assembly 140, which has a lever plate 144 defining a central bore 150 and an arm 148 with an arm end section 149. Next to the lever plate 144 is a cam plate 141 with a bore 145 that aligns with the central bore 150 of the lever plate 144. The cam plate 141 also has a cam plate end section 146 and a cam plate preload surface 142 that contacts the parking pawl 126.A spring 147 is located between the cam plate end section 146 of the cam plate 141 and the arm end section 149 of the arm 148 of the lever plate 144. A pin 143 is received by the central bore 150 of the lever plate 144 and the bore 145 of the cam plate 141, so that the cam plate 141 can rotate relative to the lever plate 144.

[0005] The parking pawl 126 has a body 128 with a first end 128a and a second end 128b. The first end 126a has a projection 107 for engaging one of the plurality of notches 105 of the metal ring 104. Opposite the projection 107 is a parking pawl preload surface 127, which is contacted by the cam plate preload surface 142. The second end 128b of the body 128 of the parking pawl 126 defines a bore 120 in which the parking pawl 126 is rotatably mounted.

[0006] A spring plate 131 has a first end 131a and a second end 131b, the second end 131b being attached to the second end 128b of the parking pawl 126. The first end 131a can be contacted by an edge 151 of the cam plate 141. A spring 108 is attached to the spring plate 131, which pushes the pivoting parking pawl out of engagement with a notch 105 of the metal ring 104. The spring 147 presses the cam plate 141 such that the projection 107 of the parking pawl 126 is pressed into a notch 105 of the metal ring 104 to prevent the output shaft 102 associated with the drive gears from rotating.

[0007] To release the parking pawl 126 from the notch 105 of the metal ring 104, the cam plate rotates towards the spring plate 131, so that the edge 151 of the cam plate 141 engages in the first end 131a of the spring plate 131 and moves the parking pawl 126 away from the notch 105 of the metal ring 104 and disengages it.

[0008] US Patent 3,704,757 A discloses a braking mechanism for a traction device. EP 4,187,130 A1 discloses a transmission system for a vehicle drive shaft. US Patent 2017 / 0234,428 A1 describes a known vehicle parking lock device. US Patent 7,229,375 B2 discloses a double-acting toothed chain and a gear with a reduced-profile gear. BRIEF DESCRIPTION OF THE INVENTION

[0009] According to one embodiment of the present invention, a parking mechanism is disclosed which is arranged on an axle drive or primary drive of a vehicle in order to engage or disengage an output shaft connected to the wheels of the vehicle.The parking mechanism comprises: a first sprocket with sprocket teeth, the first sprocket being connected to the output shaft to drive the vehicle's wheels; a second sprocket with sprocket teeth; an endless chain engaging with the sprocket teeth of the first sprocket and the sprocket teeth of the second sprocket; a parking pawl pivotably movable between an engaged position, in which the parking pawl engages the laterally extending rear portion of the first inner links of the endless loop chain, and a disengaged position, in which the parking pawl is disengaged from the laterally extending rear portion of the first inner links of the endless loop chain, in order to move the parking pawl between the engaged and disengaged positions.

[0010] The endless chain comprises: a first inner link, comprising: a body with a rear section having a first flank, a second flank, and a flat surface; a pair of teeth connected by a step section opposite the rear section; a pair of openings between the pair of teeth and the rear section; the rear section extending laterally from the body and opposite at least the step section, at least a portion of the pair of teeth, and at least a portion of the openings; a second inner link, comprising: a body with a rear section; a pair of teeth connected by a step section opposite the rear section; a pair of openings between the pair of teeth and the rear section; and guide plates arranged on the outermost sides of the endless loop chain to receive and secure the connecting pins.The first inner sections and the second inner sections are arranged in alternating nested rows in the transverse and longitudinal directions and are pivotably connected by connecting pins.

[0011] The parking pawl has a body with a first end, a second end, a top and a bottom opposite the top; a plurality of alternately arranged teeth and recesses on the bottom between the first end and the second end; and a roller rotatably attached to the first end of the body. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a conventional parking system in a parked position. Fig. Figure 2 shows a conventional parking system in an unparked position. Fig. Figure 3 shows another conventional parking system. Fig. Figure 4 shows a top view of the engagement of the parking pawl in a chain of the axle drive or primary drive. Fig. Figure 5 shows a side view of the engagement of the parking pawl with a chain of the axle drive or primary drive. Fig. Figure 6 shows a side view of the engagement of the parking lock latch with a chain. Fig. Figure 7 shows a top view of the engagement of the parking lock latch with the chain. Fig. Figure 8 shows another view of the engagement of the parking lock latch with the chain. Fig. Figure 9 shows a perspective view of the parking lock latch. Fig. Figure 10 shows another perspective view of the parking lock latch. Fig. Figure 11 shows a side view of the parking lock latch. Fig. Figure 12 shows a perspective view of the chain. Fig. Figure 13 shows an outer segment. Fig. Figure 14 shows a first inner segment. Fig. Figure 15 shows a side view of a second inner segment. Fig. Figure 16 shows a perspective view of the second inner member. DETAILED DESCRIPTION

[0012] A parking mechanism is required in a vehicle transmission to hold the vehicle firmly in position and prevent movement. Typically, a square gear is used for a given transmission, engaged by an arm that engages with this gear, as shown in the prior art above. Fig. 1-3 described. To reduce the cost and complexity of the transmission, in one embodiment of the present invention, the additional metal gear ring in the transmission would be replaced by a return chain on the axle drive or primary drive, which engages with the parking pawl. The axle drive is located on the rear axle or output shaft and is connected to the rear wheels of the vehicle, while the primary drive is located on the front axle or output shaft and is connected to the front wheels of the vehicle.

[0013] Fig. Figures 9-11 show a parking pawl 208 in an embodiment of the present invention. The parking pawl 208 has a body 255 with a first end 208a, a second end 208b, an upper surface 219 and a lower surface 220.

[0014] At the second end 208b, the body 255 defines a bore 209 in which the parking pawl 208 can rotate. The bore 209 receives a pin 211. The first end 208a of the body is forked into a first pawl arm wall 208c and a second pawl arm wall 208d, which are connected by a lower pawl wall 208e. Between the first and second pawl arm walls 208c, 208d is a roller 210 which rotates around a pin 212, the ends of which are received in the bores 215a, 215b of the first and second pawl arm walls 208c, 208d.

[0015] The lower surface 220 comprises a series of teeth 214, 213 and depressions 218, 216, 217, which from the second end 208b to the first end 208a appear as follows: a first depression 218, a first tooth 214, a second depression 216, a second tooth 213 and a third depression 217. Each tooth 214, 213 is defined by a first flank 214a, 213a, a second flank 214c, 213c and a tooth engagement surface 214b, 213b.

[0016] Fig. Figures 13-16 show the limbs that are in Fig. The chain 285 comprises the chain shown in Figure 12. The chain 285 consists of alternating sets of first inner links 265 with raised backs and second inner links 275, which interlock transversely and longitudinally and are pivotably connected by connecting pins 282 and guide plates 270, which are arranged on the outermost sides of the chain 285 to receive and secure the connecting pins 282. The chain 285 has a plurality of guide rows 280, formed from the guide plates 270 and the first inner links 265 with raised backs, which are arranged in the same longitudinal position as the guide plates 270, as well as link rows 281, formed only from the second inner links 275, which are arranged between adjacent guide rows 280.

[0017] Referring to Fig. 13, the outer guide plates 270 contain a body 270a with a step section 271 that defines and lies between a pair of toes 274. Opposite the pair of toes 274 is a concave posterior section 273. The body 270a also has pin openings 272 in each of the toes of the pair of toes 274. The step section 271 extends below the upper edge section 272a of each of the pin openings 272.

[0018] Referring to Fig. 15, the first inner segments 265 comprise a body 265a with a pedicle section 269 that defines and lies between a pair of toes 268 and a posterior section 266. The body 265a also defines a pair of openings 267. The raised posterior section 266 of the first inner segments 265 is located at least opposite the pedicle section 269 and at least a portion of the pair of openings 267 and the pair of toes 268. The raised posterior section 266 is preferably flat and extends laterally outward from an edge 265b of the body 265a and has a first flank 266a, a second flank 266b, and a flat surface 266c that connects the first flank 266a with the second flank 266b. Each toe of the pair of toes 268 has an outer flank 268b and an inner flank 268a.

[0019] Referring to Fig. 14, the second medial phalanges 275 contain a body 275a with a posterior section 277 that defines and lies between a pair of toes 279 and a posterior section 276. The body 275a also defines a pair of openings 278. The posterior section 276 of the second medial phalanges 275 is opposite the pair of openings 278, the pair of toes 279, and the posterior section 277. The posterior section 276 is preferably flat. Each toe of the pair of toes 279 has an lateral flank 279b and an lateral flank 279a.

[0020] Either the inner flank 279a, 268a or the outer flank 279b, 268b of the first inner link 275 and the second inner link 265 engage in the sprocket teeth 205, 203 of the sprockets of the axle drive or the primary drive.

[0021] Although the inner links are depicted as containing a raised section, within the scope of the invention the raised sections can also be attached to the outer links of the chain.

[0022] Fig. Figures 6-8 show the engagement of the parking lock latch with the chain.

[0023] The parking pawl 208 is movable between an engaged and a disengaged position. In the disengaged position, the lower surface 220 of the parking pawl 208 is disengaged from the rear section 276 of the second inner links 275 and the raised rear section 266 of the first inner links 275, so that the chain 206 and the sprockets 202, 204 can continue to rotate and the drive sprockets (not shown), which are connected to the output shaft 102 via the output shaft sprocket 204, can rotate.

[0024] In the inset position, the lower surface 220 of the parking pawl 208 engages with the chain 206, such that the first flank 214a of the first tooth 214 of the parking pawl 208 is inset with the second flank 266a of a raised rear section 266 of the first inner link 265, the second recess 216 being aligned with the flat surface 266c of the raised rear section 266 of another first inner link 265, the first flank 213a of the second tooth 213 of the parking pawl 208 is inset with the second flank 266a of a raised rear section 266 of another first inner link 265, and the third recess 217 of the parking pawl 208 is aligned with the flat surface 266c of a third first inner link. The tooth engagement surfaces 214b, 213b of the parking pawl 208 are arranged parallel to the rear sections 276 of the second inner members 275.When the teeth 214, 213 of the parking pawl 208 engage in the rear sections 276 of the second inner links 275 of the chain 206 and the recesses 218, 216, 217 between the teeth 214, 213 of the parking pawl 208, the engagement of the teeth 214, 213 of the parking pawl 208 with the raised rear section 266 of the chain 206 therefore prevents further rotation of the output shaft sprocket 204 and the chain 206.

[0025] Fig.Figures 4-5 show the cam assembly 200, which presses the parking pawl 208 into the engaged position. The cam assembly 200 has a stationary lever plate 221, which defines a central bore, an arm 222 with an arm end section 223, and a stop 231 extending radially from the lever plate 221. Adjacent to the lever plate 221 is a cam plate 224 with a bore 225 that aligns with the central bore of the lever plate 221. The cam plate 224 additionally has a cam plate end section 229 and a preload surface 228 that contacts the roller 210 of the parking pawl 208. Opposite the preload surface 228 is a stop surface 232 that can engage with the stop 231 of the lever plate 221. A spring 230 is located between the cam plate end section 229 of the cam plate 224 and the arm end section 223 of the arm 222 of the lever plate 221.A pin 227 is received by the bore of the lever plate 221 and the bore 225 of the cam plate 224 and held by a bearing 226, so that the cam plate 224 can rotate relative to the lever plate 221. Alternatively, the pin 227 can also be fixed to the stationary lever plate 221. The cam plate 224 is rotated into engagement with the roller 210 of the parking pawl either by a mechanical linkage or an electric drive, whereby a spring preload (not shown) is possible.

[0026] To release the parking pawl 208 from the chain 206, the cam plate 224 is rotated away from the stop 231 by the mechanical linkage or an electric actuator, whereby a spring preload (not shown) is possible. When the cam plate 224 rotates away from the stop 231, the preload surface 228 is no longer engaged with the roller 210 of the parking pawl 208 and the teeth 213, 214 no longer engage in the raised rear section 266 of the chain 206.

[0027] It is noted that a cam or over-center device can be used to maintain the engagement or disengagement of the cam plate 224 with the roller 210. The over-center device can be an over-center spring mechanism that mechanically holds the preload surface 228 of the cam plate 224 engaged with the roller 210 of the parking pawl 208 or disengaged from the bearing 226, which acts as a pivot point. The over-center device can include a tension spring, one end of which is attached to the fixed structure of the stationary lever plate 221 and the other end of which is attached to the cam plate 224.

[0028] Alternatively, two chains on a given reduction gear can engage two independent chains in a parking mechanism, thereby creating additional redundancy that would keep the vehicle stationary even in the unlikely event of a chain breakage. For example, battery-powered electric vehicles have two reduction gears to reduce the speed of the electric motor to a lower speed suitable for most road speeds. The parking function of the present invention on the chain could be used in both reduction ratios in the gearbox, depending on the packaging and position of the chain within the gearbox.

[0029] It should be noted that the parking mechanism can be used with any chain arrangement as long as the chain has raised backs into which the parking pawl can engage.

[0030] Accordingly, it is understood that the embodiments of the invention described herein merely illustrate the application of the principles of the invention. Reference to details of the embodiments presented is not intended to limit the scope of the claims, which include even those features considered essential to the invention.

Claims

[1] A parking mechanism arranged on an axle drive or primary drive of a vehicle for engaging or disengaging an output shaft (102) connected to the wheels of the vehicle, the parking mechanism comprising: a first sprocket (204) having sprocket teeth (205), the first sprocket (204) being connected to the output shaft (102) for driving the wheels of the vehicle; a second sprocket (202) with sprocket teeth (203); an endless loop chain (285) engaging the sprocket teeth (205) of the first sprocket (204) and the sprocket teeth (203) of the second sprocket (202), the endless loop chain (285) comprising: a first inner member (265) comprising: a body (265a) having a rear portion (266) with a first flank (266a), a second flank (266b), and a flat surface (266c); a pair of teeth connected by a step portion (269) opposite the rear portion (266); a pair of openings (267) between the pair of teeth and the rear portion (266); the rear portion (266) extending laterally from the body (265a) and opposing at least the step portion (269), at least a portion of the pair of teeth, and at least a portion of the openings (267); a second inner member (275) comprising: a body (275a) having a rear portion (276); a pair of teeth connected by a step portion (277) opposite the rear portion (276); a pair of openings (278) between the pair of teeth and the rear portion (276); and wherein the first inner links (265) and the second inner links (275) are laid out in alternating interleaved rows in the transverse and longitudinal directions and are pivotally connected by connecting pins (282); Guide plates (270) arranged on the outermost sides of the endless loop chain (285) for receiving and fixing the connecting pins (282); a parking pawl (208) pivotally movable between an engaged position in which the parking pawl (208) engages the laterally extending rear portion (266) of the first inner links (265) of the endless loop chain (285) and a disengaged position in which the parking pawl (208) is disengaged from the laterally extending rear portion (266) of the first inner links (265) of the endless loop chain (285), the parking pawl (208) comprising: a body (255) having a first end (208a), a second end (208b), an upper surface (219) and a lower surface (220) opposite the upper surface (219); a plurality of alternating teeth (213, 214) and recesses (216, 217, 218) on the lower surface (220) between the first end (208a) and the second end (208b); and a roller (210) rotatably mounted on the first end (208a) of the body (255); and a cam assembly (200) for moving the parking pawl (208) between the engaged position and the disengaged position. [2] The parking mechanism of claim 1, wherein the first end (208a) of the parking pawl (208) is forked to receive the roller (210). [3] The parking mechanism of claim 1, wherein the cam assembly (200) further comprises: a stationary lever plate (221) having a central hole, an arm (222) with a spring projection and a stop (231); a rotatable cam plate (224) having a central hole, a spring projection, a biasing surface (228) configured to contact the roller (210) of the parking pawl (208), and a stop surface (232) configured to contact the stop (231) of the stationary lever plate (221); a pin (227) received in the central hole of the stationary lever plate (221) and the central hole of the rotatable cam plate (224), the pin (227) being fixed to the stationary lever plate (221); and a spring (230) mounted between the spring projection of the stationary lever plate (221) and the spring projection of the rotatable cam plate (224).

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