Chassis of electric tractor

Abstract

The present invention has been devised in consideration of a chassis which can meet the requirements of an agricultural electric tractor. A chassis (100) of an electric tractor (10) according to the present invention comprises: a battery frame (110) having a front side which supports a battery pack (B) and a rear side which forms an installation space (IS); and a motor case (120) which is installed in the installation space (IS) and has a rear end coupled to a transmission case (130), wherein the battery frame (110) comprises: a front frame (111) which supports the battery pack (B) positioned above; and a rear frame (112) which extends rearward from the rear end of the front frame (111) to form the installation space (IS). According to the present invention, the chassis (100) of the electric tractor (10) can be configured using the motor case (120).

Description

electric tractor chassis

[0001] The present invention relates to a chassis that determines the structure of an electric tractor.

[0002] An agricultural tractor is a work vehicle capable of performing various types of agricultural tasks by attaching and detaching multiple implements.

[0003] Agricultural tractors need to have a robust structure because they need to perform work on rough terrain such as slopes or wetlands.

[0004] The structure of an agricultural tractor and the arrangement of its components are based on the chassis on which most of the components are mounted.

[0005] Conventional internal combustion engine tractors have a structure in which the engine, clutch, and transmission are directly connected in the front-rear direction. The engine housing and clutch case are made of metal materials with excellent mechanical strength, so the aforementioned direct connection structure itself can form the basic chassis of an agricultural tractor.

[0006] Meanwhile, advancements in battery technology have prompted attempts to replace vehicle power sources from internal combustion engines to electric motors, and such efforts have been actively pursued for agricultural work vehicles such as tractors and combines. Naturally, these attempts have manifested as modifications or conversions of existing internal combustion engine tractors into electric tractors.

[0007] Electric tractors do not possess the engines and clutches found in conventional internal combustion engine tractors; instead, they require batteries and motors. The weight, shape, and rigidity of batteries and motors cannot fully correspond to those of engine housings and clutch cases. Consequently, it is difficult to simply modify the chassis structure—including engine housings, clutch cases, and transmission cases—that was provided for conventional internal combustion engine tractors to be suitable for electric tractors.

[0008] In other words, a new chassis suitable for electric tractors is required.

[0009] Meanwhile, the chassis must be designed not only to determine the basic structure of the tractor (with sufficient consideration of rigidity and weight distribution), but also to facilitate the installation or support of other components (e.g., steering columns).

[0010] [Prior Art Literature]

[0011] [Patent Literature]

[0012] (Patent Document 1) Republic of Korea Published Patent No. 10-2023-0062395 (May 9, 2023)

[0013] This invention was conceived from consideration of a chassis that meets the requirements of an agricultural electric tractor.

[0014] The chassis (100) of an electric tractor (10) according to the present invention comprises: a battery frame (110) that supports a battery pack (B) at the front and forms an installation space (IS) at the rear; a motor case (120) disposed in the installation space (IS) formed by the battery frame (110); and a transmission case (130) coupled to the rear end portion of the motor case (120); wherein the battery frame (110) comprises a front frame (111) that supports the battery pack (B); and a rear frame (112) coupled to the rear end portion of the front frame (111) to form the installation space (IS); and wherein the rear frame (112) extends in the front-rear direction and is provided on the left side of the installation space (IS) as a left support plate (112-b). and a right support plate (112-c) that is spaced apart from the left support plate (112-b) at a certain distance to form the installation space (IS) between the left support plate (112-b) and the right support plate (112-c) that is extended in the front-rear direction on the right side of the installation space (IS); wherein the left support plate (112-b) is coupled to the left side of the motor case (120) and the right support plate (112-c) is coupled to the right side of the motor case (120).

[0015] One end of the left support plate (112-b) is connected to the left side of the transmission case (130), and one end of the right support plate (112-c) is connected to the right side of the transmission case (130).

[0016] The motor case (120) comprises a motor case body (121) having a placement space (AS) in which a motor (M) can be placed, and the motor case body (121) comprises a first left coupling part (123l) to which a left bottom plate frame (lF) is coupled; and a first right coupling part (123r) to which a right bottom plate frame (rF) is coupled.

[0017] The motor case (120) comprises: a motor case body (121) having a placement space (AS) in which a motor (M) can be placed; and a support part (122) integrally formed with the motor case body (121) and supporting a steering column (C).

[0018] The support member (122) is formed by protruding from one side of the motor case body (121).

[0019] The motor case (120) further includes a second left coupling part (124l) to which a left bracket (lB) for supporting the battery pack (B) is coupled; and a second right coupling part (124r) to which a right bracket (rB) for supporting the battery pack (B) is coupled; wherein the second left coupling part (124l) is formed to protrude to the left from the support part (122), and the second right coupling part (124r) is formed to protrude to the right from the support part (122).

[0020] The motor case (120) comprises a motor case body (121) having a placement space (AS) in which a motor (M) can be placed; and the motor case body (121) comprises a second left coupling part (124l) to which a left bracket (lB) for supporting the battery pack (B) is coupled; and a second right coupling part (124r) to which a right bracket (rB) for supporting the battery pack (B) is coupled.

[0021] The above motor case (120) includes a first installation part (126) in which a parking lever (PL) is installed to fix the brake pedal (P) in a lowered state.

[0022] The motor case (120) includes a second installation part (127) in which a pedal shaft (PA) for supporting a brake pedal (P) is installed.

[0023] The motor case (120) has a shaft space (SS) in which a shaft (S) extending from the rear axle to the front axle (FA) is installed, and the shaft (S) is coupled to the motor case (120) through a bearing (B).

[0024] On the upper surface of the motor case (120), a pipe hole (pH) through which a cooling pipe passes to cool the motor (M) placed in the installation space (IS) and a connector hole in which a connector is installed to electrically connect the inverter (I) and the motor (M) are formed.

[0025] According to the present invention, a chassis of an electric tractor utilizing a battery frame and a motor case is provided.

[0026] According to one embodiment of the present invention, a chassis is provided in which a battery frame, a motor case, and a transmission case are each firmly coupled to one another, thereby improving the structural stability of an electric tractor.

[0027] According to one embodiment of the present invention, the dynamic stability of an electric tractor can be increased by firmly coupling a heavy-duty battery to a chassis and arranging the battery, inverter, motor, and transmission side by side in the front-rear direction.

[0028] According to one embodiment of the present invention, components of a conventional tractor, such as a steering column, cooling pipe, parking lever (PL), brake pedal, brake link, shaft, shaft cover, implement, and cable, can be appropriately installed and arranged, making it possible to design an electric tractor while maintaining the component structure of a conventional internal combustion engine tractor.

[0029] In addition, various additional effects may be available according to different embodiments of the present invention. These are described in the description of the relevant embodiments.

[0030] FIG. 1 is a perspective view illustrating the core configuration of an electric tractor according to the present invention.

[0031] Figure 2 is a simplified plan view of the chassis of an electric tractor according to Figure 1.

[0032] Fig. 3 is a perspective view of the front frame according to Fig. 2.

[0033] FIG. 4 is an exploded perspective view including the rear frame of the chassis according to FIG. 2.

[0034] FIG. 5 is a left exploded perspective view including the motor case according to FIG. 1.

[0035] FIG. 6 is an exploded perspective view of the right side including the motor case according to FIG. 1.

[0036] FIG. 7 is a cross-sectional view in the X direction including the motor case according to FIG. 1.

[0037] FIG. 8 is a cross-sectional view in the Y direction including the motor case according to FIG. 1.

[0038] FIG. 9 is a lower exploded perspective view including the motor case according to FIG. 1.

[0039] Preferred embodiments according to the present invention are described with reference to the accompanying drawings, provided that for the sake of brevity, descriptions of well-known configurations are omitted or compressed as much as possible.

[0040] In this specification, rolling means that an electric tractor (10) (including its configuration) rotates and vibrates around an axis in the direction of travel (forward-backward direction).

[0041] General Overview of Electric Tractors

[0042] FIG. 1 is a perspective view illustrating the core configuration of an electric tractor (10) according to the present invention.

[0043] Referring to FIG. 1, an electric tractor (10) according to one embodiment of the present invention will be described schematically.

[0044] The electric tractor (10) includes a chassis (100), a battery pack (B), a motor (M), an inverter (I: see FIG. 2), a transmission (T), an axle case (AC), a brake pedal (P), a front axle (FA: see FIG. 3), a shaft (S: see FIG. 7), a steering column (C), and a floor plate frame (F: lF, rF).

[0045] The chassis (100) forms the basic frame of the electric tractor (10), allowing the components of the electric tractor (10) to be properly installed and arranged.

[0046] The chassis (100) includes a battery frame (110), a motor case (120), and a transmission case (130).

[0047] The battery pack (B) is placed on the upper part of the chassis (100). The battery pack (B) may be composed of a battery module that stores electrical energy and a battery management device that manages the battery module.

[0048] The battery pack (B) can provide electrical energy in the form of direct current.

[0049] The motor (M) converts electrical energy provided from the battery pack (B) into kinetic energy. The motor (M) can generate kinetic energy by rotating based on the electrical energy provided from the battery pack (B).

[0050] The kinetic energy generated by the motor (M) is transferred to the rear axle coupled to the axle case (AC) via the transmission (T).

[0051] The motor (M) can receive electrical energy in the form of alternating current.

[0052] The motor (M) can be placed in a placement space formed in the chassis (100).

[0053] The motor (M) can be placed inside the motor case (120).

[0054] The inverter (I) is positioned at the front of the motor (M) and converts the electrical energy in the form of direct current provided by the battery pack (B) into alternating current and transmits it to the motor (M).

[0055] The inverter (I) and the motor (M) can be electrically connected to each other via cables and connectors.

[0056] The inverter (I) is installed on the lower middle side of the chassis (100).

[0057] The transmission (T) is provided for shifting the electric tractor (10). The transmission (T) can adjust the rotational speed and rotational force of the kinetic energy provided by the motor (M) and transmit it to the rear axle.

[0058] The transmission (T) is provided inside the transmission case (130) which forms the rear portion of the chassis (100).

[0059] The axle case (AC) is installed at the rear of the chassis (100).

[0060] The axle case (AC) can be directly connected to the transmission case (130).

[0061] The axle case (AC) is provided to install the rear axle.

[0062] Generally, the rear axle is connected to both sides of the axle case (AC). The rear axle transmits kinetic energy provided by the transmission (T) to the rear wheels of the electric tractor (10).

[0063] The rear axle is installed on the lower rear side of the chassis (100).

[0064] The brake pedal (P) is provided for braking the rear wheels.

[0065] The brake pedal (P) is connected to the rear axle through a braking link (lPL, rPL: see FIG. 1 and FIG. 5).

[0066] The rear axle receives the braking force applied to the brake pedal (P) through the braking links (lPL, rPL) and brakes the rear wheel.

[0067] Two brake pedals (P) are provided, a left brake pedal (lP) and a right brake pedal (rP), so that each rear wheel on the left and right sides can be braked respectively. Two braking links (lPL, rPL) are also provided, a left braking link (lPL: see FIG. 5) and a right braking link (rPL: see FIG. 1).

[0068] The brake pedal (P) is installed on the right side of the chassis (100).

[0069] The front axle (FA) is located at the front and supports the chassis (100) of the electric tractor (10), which will be described later, from the front.

[0070] The electric tractor (10) may have a shaft (S, see FIG. 7) extending from the rear axle to the front axle (FA). The shaft (S) transmits power from the rear axle to the front axle (FA), thereby enabling the electric tractor (10) to operate in a four-wheel drive manner.

[0071] The front axle (FA) is installed on the front side of the chassis (100).

[0072] A steering column (C) is provided to control the steering of the electric tractor (10).

[0073] The steering column (C) is connected to the front axle (FA) via hydraulic piping (not shown).

[0074] The front axle (FA) steers the front wheels according to the operation of the steering column (C).

[0075] The steering column (C) is installed on the upper middle side of the chassis (100).

[0076] The floor plate frame (F) includes a left floor plate frame (lF) and a right floor plate frame (rF) that extend to the left and right, respectively, from the center of the electric tractor (10).

[0077] A pair of floor plate frames (lF, rF) serve as the foundation for forming the floor of the driver's seat.

[0078] The unexplained symbols X and Y in FIG. 1 will be related to the cross-sectional views in FIG. 7 and FIG. 8 later.

[0079] Next, we will examine the chassis (100) of the electric tractor (10) according to the present invention in more detail.

[0080] Explanation of the electric tractor chassis

[0081] FIG. 2 is a schematic plan view of the chassis (100) of the electric tractor (10) according to FIG. 1.

[0082] In FIG. 2, the positions of the motor case (120), transmission case (130), motor (M), and transmission (T) are shown with dashed lines.

[0083] The chassis (100) of the electric tractor (10) according to FIG. 2 may include a battery frame (110), a motor case (120), and a transmission case (130).

[0084] The battery frame (110), motor case (120), and transmission case (130) are firmly joined to each other to form the chassis (100) of the electric tractor (100).

[0085] Referring to FIGS. 1 and 2, the battery frame (110) is configured to support the battery pack (B) at the front and form an installation space (IS) at the rear.

[0086] In Fig. 2, the installation space (IS) is indicated by a thick dotted line.

[0087] The installation space (IS) is formed to accommodate at least a portion of the inverter (I), motor case (120), and transmission case (130).

[0088] The battery frame (110) may include a front frame (111) and a rear frame (112).

[0089] FIG. 3 is a perspective view of the front frame (111) of FIG. 2.

[0090] The front frame (111) supports the battery pack (B) located above.

[0091] The front frame (111) may have a plurality of support members (111-a to 111-f) for supporting the battery pack (B). Correspondingly, the battery pack (B) may have a coupling member (Ba to Bf) that is coupled to each support member (111-a to 111-f).

[0092] The structure is formed such that the supporting member (111-a to 111-f) and the connecting member (Ba to Bf) are connected to each other while the connecting projection (cb-a) of the supporting member (111-a to 111-f) is inserted through the connecting hole (ch) in the connecting member (Ba to Bf).

[0093] The support members (111-a to 111-f) are provided with a cushioning means (sa) for cushioning.

[0094] The cushioning means (sa) mitigates the impact of the electric tractor (10) being transmitted to the battery pack (B).

[0095] A front axle (FA) is installed below the front frame (111).

[0096] The front frame (111) has mounting portions (IP-a, IP-b) for mounting a front axle (FA). The front axle (FA) can be mounted to the front frame (111) by mounting the front axle (FA) to the mounting portions (IP-a, IP-b).

[0097] The front axle (FA) may be installed in the installation portions (IP-a, IP-b) of the front frame (111) via a separate bracket.

[0098] The front axle (FA) is coupled to the front frame (111) to support the battery frame (110) or chassis (100) at the lower side of the front frame (111).

[0099] FIG. 4 is an exploded view including the rear frame (112) of the chassis (100) according to FIG. 2.

[0100] The rear frame (112) is combined with a motor case (120), a transmission case (130), and an inverter (I).

[0101] As shown in FIGS. 2 and 4, the rear frame (112) is provided to extend from the rear end of the front frame (111) toward the rear to form an installation space (IS).

[0102] The rear frame (112) includes a connecting plate (112-a), a left support plate (112-b), and a right support plate (112-c).

[0103] The connecting plate (112-a) is connected to the rear end of the front frame (111) by a connecting means such as a bolt.

[0104] The left support plate (112-b) is provided on the left side in a long forward-backward direction.

[0105] The shear portion of the left support plate (112-b) is connected and fixed to the left end of the connecting plate (112-a).

[0106] The rear portion of the left support plate (112-b) is connected and fixed to the left side of the motor case (120) by a connecting means such as a bolt.

[0107] The right support plate (112-c) is provided lengthwise in the front-rear direction to the right of the left support plate (112-b).

[0108] The front portion of the right support plate (112-c) is connected and fixed to the right end of the connecting plate (112-a).

[0109] The rear portion of the right support plate (112-c) is connected and fixed to the right side of the motor case (120) by means of a connecting means such as a bolt.

[0110] The left support plate (112-b) is further attached to the left side of the transmission case (130), and the right support plate (112-c) is further attached to the right side of the transmission case (130).

[0111] The left support plate (112-b) and the right support plate (112-c) are each provided with a support member (112-bI, 112-cI) for supporting and installing an inverter (I).

[0112] The inverter (I) is coupled to the left support plate (112-b) and the right support plate (112-c) via support members (112-bI, 112-cI).

[0113] The right support plate (112-c) is spaced apart from the left support plate (112-b) at a certain distance, thereby forming an installation space (IS) between it and the left support plate (112-b).

[0114] The inverter (I) is positioned at the front end of the installation space (IS) adjacent to the battery pack (B).

[0115] Referring to FIG. 2, the motor case (120) is installed on the installation space (IS) at a distance (G) from the inverter (I) and positioned further back.

[0116] The motor case (120) and the inverter (I) are arranged so as to be separated by a predetermined distance (G) in the front-rear direction. This distance (G) can be used as a passage for cables to supply electrical energy from the inverter (I) to the motor (M), hydraulic pipes connecting the steering column (C) and the front axle (FA), cooling pipes connecting the radiator support and the motor (M), and various hydraulic pipes in the hydraulic system of the electric tractor (10).

[0117] The rear end of the installation space (IS) provides space for a part of the transmission case (130) to be installed. Thus, the inverter (I), motor case (120), and transmission case (130) are arranged side by side in the front-rear direction.

[0118] The motor case (120) is placed on the installation space (IS).

[0119] The rear end of the motor case (120) can be directly connected to the front end of the transmission case (130).

[0120] A motor (M) is placed inside the motor case (120).

[0121] The motor case (120) can be placed on the installation space (IS) by connecting its left side to the left support plate (112-b) and its right side to the right support plate (112-c).

[0122] As described above, the chassis (100) of the electric tractor (10) according to the present invention has a structure in which a battery frame (110), a motor case (120), and a transmission case (130) are combined. This chassis (100) can fully replace the structural function of the chassis (100) of a conventional internal combustion engine tractor, which is centered around an engine housing, a clutch case, and a transmission case.

[0123] In addition, according to the combined structure between the components described above, the battery frame (110), motor case (120), and transmission case (130) are firmly joined to each other to form a chassis (100), thereby ensuring the structural stability of the electric tractor (10).

[0124] The motor case (120) will be described in detail with reference to FIGS. 5 to 9.

[0125] FIG. 5 is a left exploded perspective view including the motor case (120) in FIG. 1.

[0126] FIG. 6 is an exploded perspective view of the right side including the motor case (120) in FIG. 1.

[0127] FIG. 7 is a cross-sectional view in the X direction including the motor case (120) in FIG. 1.

[0128] FIG. 8 is a cross-sectional view in the Y direction including the motor case (120) in FIG. 1.

[0129] FIG. 9 is a lower exploded perspective view including the motor case (120) in FIG. 1. In FIG. 9, some components are omitted for convenience of illustration.

[0130] FIGS. 5 to 9 show various configurations combined or installed via a motor case (120).

[0131] The motor case (120) has a motor case body (121), a support part (122), a first left coupling part (123l), a first right coupling part (123r), a second left coupling part (124l), a second right coupling part (124r), a third coupling part (125: see FIG. 7), a first installation part (126), a second installation part (127), and a third installation part (128: see FIG. 7).

[0132] According to FIG. 7, the motor case body (121) forms a placement space (AS) in which a motor (M) can be placed.

[0133] The motor (M) may be coupled to the rear transmission (T) or transmission case (130) but may not be supported by the motor case body (121). That is, the motor (M) may be placed in the placement space (AS) spaced apart from the inner surface of the motor case (120).

[0134] However, a structure in which the motor (M) is coupled to and supported by the motor case body (121) by a separate coupling part provided on the inside of the motor case body (121) may also be considered.

[0135] The first left connecting part (123l) is provided so that the left bottom plate frame (lF) is connected.

[0136] The first left coupling part (123l) is provided to protrude to the left from the motor case body (121).

[0137] For productivity, the left floor plate frame (lF) can retain the structure applied to existing internal combustion engine tractors and coupled to the clutch case. In this case, to use the floor plate frame (IF) for internal combustion engine tractors as is, the first left coupling part (123l) can be formed to protrude to the left.

[0138] The front end of the left bottom plate frame (lF) is connected to the first left connecting part (123l), and the rear end of the left bottom plate frame (lF) is connected to the left side of the transmission case (130) to improve structural rigidity.

[0139] The first right connecting part (123r) is provided so that the right bottom plate frame (rF) is connected.

[0140] The first right connecting part (123r) is provided to protrude to the right from the motor case body (121).

[0141] The description of the first right connecting part (123r) and the right bottom plate frame (rF) is replaced by the description of the first left connecting part (123l) and the left bottom plate frame (lF) described above.

[0142] The support member (122) is integrally formed with the motor case body (121) and is provided to support the steering column (C).

[0143] The lower surface of the steering column (C) is connected to the upper side of the support member (122) in a structure that contacts the upper surface of the support member (122).

[0144] The main body (Ca) of the steering column (C) can be connected to the support member (122) via a connecting member (Cb).

[0145] A connecting member (Cb) is connected to the upper surface of the support member (122), and the main body (Ca) of the steering column (C) is connected to the connecting member (Cb).

[0146] For productivity, the steering column (C) can also be applied as is from a conventional internal combustion engine tractor. To this end, it is preferable that the support member (122) be formed to be raised above the upper surface of the motor case body (121).

[0147] By raising the support portion (122) appropriately, the motor case (120) corresponds to the specifications of the existing steering column (C).

[0148] On the other hand, the upper surface of the motor case body (121) is sunken relative to the support member (122), making it easy to configure the floor of the driver's seat.

[0149] The second left connecting part (124l) is provided to be connected to a left bracket (lB) that supports the battery pack (B).

[0150] The second left connecting part (124l) is provided to protrude to the left from the support part (122).

[0151] The second right coupling part (124r) is provided to be coupled with a right bracket (rB) that supports the battery pack (B).

[0152] The second right connecting part (124r) is provided to protrude to the right from the support part (122).

[0153] The left bracket (lB) and the right bracket (rB) each extend forward from the second left coupling part (124l) and the second right coupling part (124r), respectively. This is to additionally support the battery pack (B).

[0154] A coupling member (Bg, Bh) may be provided at the rear of the battery pack (B), respectively. The coupling member (Bg, Bh) is fixed and coupled to the left bracket (lB) and the right bracket (rB).

[0155] A cushioning means (sm) is provided at the front portions of the left bracket (lB) and the right bracket (rB). The cushioning means (sm) mitigates the transmission of shocks to the battery pack (B) through the motor case (120) when the electric tractor (10) is in operation.

[0156] According to the above structure, the motor case (120) having a second left coupling part (124l) and a second right coupling part (124r) can stably support the rear of the battery pack (B) by interposing the left bracket (lB) and the right bracket (rB), while also being able to more firmly connect the battery pack (B) to the chassis (100).

[0157] The second left connecting part (124l) is formed to protrude to the left from the support part (122).

[0158] The second left connecting part (124l) is formed by extending to the left from the left side of the raised supporting part (122).

[0159] The second right connecting part (124r) is formed to protrude to the right from the support part (122).

[0160] The second right connecting part (124r) is formed by extending to the right from the right side of the raised support part (122).

[0161] The front portions of the left bracket (lB) and the right bracket (rB) have a structure that supports the rear end of the battery pack (B) at both left and right ends. This structure suppresses the rotational freedom of the battery pack (B) with the front-rear direction as an axis. Therefore, rolling of the battery pack (B) is suppressed during the operation of the electric tractor (10).

[0162] The first installation part (126) is a part where a parking lever (PL) is installed to fix the brake pedal (P) in a lowered state on the side adjacent to the brake pedal (P).

[0163] The parking lever (PL) can be rotatably coupled to the first installation part (126) via a fixed member (RE) and an elastic member (EE) from the left.

[0164] As shown in FIG. 7, the elastic member (EE) is provided to apply torque in direction A to the parking lever (PL).

[0165] When the driver rotates the parking lever (PL) in the opposite direction to A, the parking lever (PL) has a restoring force that attempts to return it to A. However, the parking lever (PL) engages with the parking pin (PP) of the lowered left brake pedal (lP), thereby preventing the brake pedal (P) from rising.

[0166] The fixed member (RE) is installed between the elastic member (EE) and the first installation part (126).

[0167] The fixed member (RE) is installed in the first installation part (126) by means of a coupling means.

[0168] The fixed member (RE) can have resistance to torque in direction A.

[0169] The fixed member (RE) prevents the parking lever (PL) from over-rotating in direction A due to the torque applied by the elastic member (EE). Therefore, the parking lever (PL) can be maintained in its original position despite the torque applied by the elastic member (EE).

[0170] To improve productivity, the positions of the brake pedal (P) and the driver's seat may be the same as those of a conventional internal combustion engine tractor. In this case, the parking lever (PL), which functions in conjunction with the brake pedal (P), also needs to be in the same position as the existing one. Therefore, the first mounting part (126) is provided to protrude toward the brake pedal (P).

[0171] The first installation part (126) is provided to protrude toward the brake pedal (P), so that the parking lever (PL) can be positioned to engage with the parking pin (PP) provided on the brake pedal (P).

[0172] The second installation part (127) is a part for installing a pedal shaft (PA) that supports a brake pedal (P).

[0173] The brake pedal (P) may include a left brake pedal (lP) and a right brake pedal (rP).

[0174] The second installation part (127) has a structure that forms a hollow (PAh) on both the left and right sides of the motor case (120), and the pedal shaft (PA) is installed in the second installation part (127) in a structure that is inserted by passing through the hollow (PAh) formed on both the left and right sides.

[0175] The pedal shaft (PA) is installed by penetrating the motor case (120) in the left and right directions.

[0176] The pedal shaft (PA) is rotatably supported by the second installation part (127).

[0177] The left brake pedal (lP) and the right brake pedal (rP) are supported and installed on the right side of the pedal shaft (PA).

[0178] The left brake pedal (lP) and the pedal shaft (PA) are installed to be fixed by a fixing means (fm). When the driver applies pressure to the left brake pedal (lP) to lower the left brake pedal (lP), the pedal shaft (PA) rotates in direction A.

[0179] A left braking link (lPL) for braking the left rear wheel of the electric tractor (10) is connected to the left side of the pedal shaft (PA). An arm (la) is provided on the left side of the pedal shaft (PA), and a left braking link (lPL) is hinge-connected to one end of the arm (la).

[0180] When the driver applies force to the left brake pedal (lP), the left brake pedal (lP) descends. When the left brake pedal (lP) descends, the pedal shaft (PA) rotates, and the force is transmitted to the rear axle through the left brake link (lPL), causing the rear axle to brake the left rear wheel.

[0181] A right braking link (rPL) for braking the right rear wheel of the electric tractor (10) is connected to the right braking pedal (rP). When the driver applies force to the right braking pedal (rP), the force is transmitted to the rear axle through the right braking link (rPL), allowing the right rear wheel to be braked.

[0182] The motor case (120) may form a shaft space (SS) for the shaft (S) to be positioned on the inside. The motor case (120) may be provided so that its rear surface protrudes downward to form the shaft space (SS). The motor case (120) may form a shaft hole (SH) for the shaft (S) to pass through at the bottom of the front portion.

[0183] The shaft (S) is supported and fixed to the motor case (120) in a rotatable structure by placing a bearing (R) on the shaft hole (SH).

[0184] Generally, when operating four-wheel drive, problems such as shaking or interference with other parts may occur due to the long length of the shaft (S). Therefore, a cover that surrounds the shaft (S) is often constructed. However, in the present invention, the motor case (120) is utilized instead of a separate cover that surrounds the shaft (S) in at least the area where the motor case (120) is located.

[0185] The shaft (S) is positioned in the shaft space (SS) formed inside the motor case (120), thereby preventing interference with other parts.

[0186] The shaft (S) is fixed to the motor case (120) via a bearing (R), thereby preventing shaking.

[0187] The shaft (S) extending from the rear axle to the front axle (FA) may have a joint (J) in the area of ​​the motor case (120).

[0188] The motor case (120) may have a joint hole (JH) on its back surface. The joint hole (JH) is formed in a position accessible from the outside to the shaft space (SS) where the joint (J) is located.

[0189] The joint hole (JH) can be shielded by a cover member (CE).

[0190] A person who maintains the electric tractor (10) can access the joint (J) of the shaft (S) through the joint hole (JH) to maintain the shaft (S).

[0191] The third connecting part (125) can be used as a part to which a shaft cover that protects the shaft (S) is connected.

[0192] A shaft cover may be provided to prevent the shaft (S) from being exposed to the floor in the area extending from the front end of the motor case (120) to the front axle (FA). The front end of the shaft cover may be connected to the front axle (FA).

[0193] The shaft cover can be connected to a third connecting part (125) located at the lower front portion of the motor case (120) at its rear end.

[0194] According to FIGS. 7 and 9, the third installation part (128) can be utilized as a part for installing a work device. The third installation part (128) may have two connecting holes (ch) for connecting the work device. The work device may be installed in a structure that is connected to the motor case (120) by a connecting means such as a bolt.

[0195] The implement can be a lawn mower.

[0196] According to the present embodiment, the front of the motor case (120) is open to form a connection passage for a cable connecting the motor (M) and the inverter (I).

[0197] The motor case (120) may have a pipe hole (pH) on its upper surface through which a cooling pipe extending to the motor (M) passes to cool the motor (M).

[0198] Since the part connected to the cooling pipe may differ depending on the type of motor (M), the location of the pipe hole (pH) may vary depending on the electric tractor (100).

[0199] Depending on the implementation, the motor case (120) may have a first pipe hole (pH-a) and a second pipe hole (pH-b). In this case, the motor case (120) may be compatible with all different types of motors (M). This simplifies the production line of the motor case (120) and contributes to cost reduction.

[0200] Furthermore, either the first pipe hole (pH-a) or the second pipe hole (pH-b) can be replaced with a connector hole in which a connector is placed to electrically connect the inverter (I) and the motor (M).

[0201] When a pipe hole (pH) and a connector hole are formed, there is an advantage in that the fault can be easily determined and maintenance work can be performed without the need to disassemble the motor case (120) during parts maintenance.

[0202] The above-described embodiments are merely illustrative examples of the present invention and may have various applications. Therefore, the present invention should not be understood as being limited only to the contents described above. Instead, the scope of the present invention should be understood as the separately described claims and their equivalents.

Claims

1. A battery frame (110) that supports the battery pack (B) at the front and forms an installation space (IS) at the rear; A motor case (120) disposed in the installation space (IS) formed by the battery frame (110); and A transmission case (130) coupled to the rear portion of the motor case (120); comprising, The battery frame (110) above A front frame (111) supporting the battery pack (B); and It includes a rear frame (112) that is coupled to the rear end portion of the front frame (111) to form the installation space (IS); The above rear frame (112) A left support plate (112-b) extended in the front-rear direction and provided on the left side of the installation space (IS); and It includes a right support plate (112-c) that is spaced apart from the left support plate (112-b) at a certain distance to form the installation space (IS) between the left support plate (112-b) and the right support plate (112-c) and extends in the front-rear direction to the right of the installation space (IS); wherein the left support plate (112-b) is coupled to the left side of the motor case (120) and the right support plate (112-c) is coupled to the right side of the motor case (120). The chassis (100) of an electric tractor (10).

2. In Paragraph 1 One end of the left support plate (112-b) is coupled to the left side of the transmission case (130), and one end of the right support plate (112-c) is coupled to the right side of the transmission case (130). The chassis (100) of an electric tractor (10).

3. In Paragraph 1 The above motor case (120) It includes a motor case body (121) having a placement space (AS) in which a motor (M) can be placed, and The above motor case body (121) A first left connecting part (123l) to which a left bottom plate frame (lF) is connected; and a first right connecting part (123r) to which a right bottom plate frame (rF) is connected; comprising The chassis (100) of an electric tractor (10).

4. In Paragraph 1 The above motor case (120) A motor case body (121) having a placement space (AS) in which a motor (M) can be placed; and A support member (122) integrally formed on the motor case body (121) and supporting a steering column (C); comprising The chassis (100) of an electric tractor (10).

5. In Paragraph 4 The support member (122) is formed protruding from one side of the motor case body (121). The chassis (100) of an electric tractor (10).

6. In Paragraph 5 The above motor case (120) A second left coupling part (124l) to which a left bracket (lB) for supporting the battery pack (B) is coupled; and It further includes a second right coupling part (124r) to which a right bracket (rB) for supporting the battery pack (B) is coupled; and The second left connecting part (124l) is formed to protrude to the left from the support part (122), and The second right coupling part (124r) is formed to protrude to the right from the support part (122). The chassis (100) of an electric tractor (10).

7. In Paragraph 1 The above motor case (120) A motor case body (121) having a placement space (AS) in which a motor (M) can be placed; comprising, The above motor case body (121) A second left coupling part (124l) to which a left bracket (lB) for supporting the battery pack (B) is coupled; and A second right coupling part (124r) to which a right bracket (rB) for supporting the battery pack (B) is coupled; comprising The chassis (100) of an electric tractor (10).

8. In Paragraph 1 The above motor case (120) includes a first installation part (126) in which a parking lever (PL) for fixing the brake pedal (P) in a lowered state is installed. The chassis (100) of an electric tractor (10).

9. In Paragraph 1 The above motor case (120) includes a second installation part (127) in which a pedal shaft (PA) for supporting a brake pedal (P) is installed. The chassis (100) of an electric tractor (10).

10. In paragraph 1 The motor case (120) has a shaft space (SS) in which a shaft (S) extending from the rear axle to the front axle (FA) is installed. The shaft (S) is coupled to the motor case (120) via a bearing (B). The chassis (100) of an electric tractor (10).

11. In Paragraph 1 On the upper surface of the motor case (120), a pipe hole (pH) through which a cooling pipe passes to cool the motor (M) placed in the installation space (IS) and a connector hole in which a connector is installed to electrically connect the inverter (I) and the motor (M) are formed. The chassis (100) of an electric tractor (10).

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