driving motor The invention relates to a drilling machine comprising a drilling shaft, a driving motor in a motor housing, a gear box housing, a shaft driven by the motor and extending into the gear box housing, and a transmission in the gear box housing, between the shaft driven by the motor and the drilling shaft, in order to rotate the drilling shaft at a desired rotation speed. The invention relates particularly to a core drilling machine in which a working tool part consists of a core drill and water being arranged to be supplied to the tool during operation.52357

 BACKGROUND OF THE INVENTION

 [0002] Core drills are widely used within the contracting industry in order to make holes in walls, roofs and/or floors. In case these consist of bricks, concrete or the like, water must be supplied during work. Normally this takes place via a channel in the drilling shaft. Conventionally, the water is led into the channel of the drilling shaft via the front part of the gear box housing. This has some considerable drawbacks; firstly, the drilling shaft is large in this part of the transmission, which means that the radial lip seals that are necessary in order to prevent water leakage must be made correspondingly large, which in turn makes the sealing more difficult and results in the seals getting worn out relatively quickly due to the high circumferential speed of the drilling shaft in the sealed portion, and secondly, extensive dismantling of large portions of the gear box, the drilling shaft and/or the gear box housing is often required when the seals are to be exchanged.

 [0003] Also in connection with the changing of bearings or other repair or maintenance operations, extensive dismantling must be performed in case of prior art core drilling machines, e.g. involving the emptying of oil from the gear box housing. In practice, extensive dismantling of the front parts of the core drilling machine, comprising the gear box housing, may be required also when repair or maintenance operations are to be conducted on the motor housing.

 [0004] GB 883684 as well as 125733 shows an example of a drilling machine that results in many of these problems in connection with dismantling and repair. Both of these have a single and common end cover between the motor housing and the gear box housing.

 BRIEF DESCRIPTION OF THE INVENTION

 [0005] The object of the invention is to address the abovementioned complex of problems. According to a first aspect of the drilling machine according to the invention it is characterised in:

that a longitudinal outgoing channel is arranged in the drilling shaft for supply of water to a tool part that is connected or connectable to the drilling shaft,

that a room between the motor housing and the gear box housing is arranged to be filled with water and to be water filled during operation of the drilling machine,

that an incoming water conduit for filling water into said room extends from the outside and into said room,

that a rear section of the drilling shaft extends into said water filled room between the motor housing and the gear box housing, and

that the outgoing water conduit of the drilling shaft is in communication with said room, via said rear section of the drilling shaft that extends into said room,

that said motor housing has a motor housing end cover and that said gear box housing has a gear box housing end cover.

 [0012] The latter feature in particular will create opportunities for a simplified dismantling and changing of bearings and seals, e.g.

 [0013] According to the embodiment, the drilling shaft hence extends without interruption through the entire gear box housing and into the water filled room between the gear box housing and the motor housing. In the embodiment, the invention makes use of the typical feature of conventional core drilling machines with gear boxes, that the diameter of the drilling shaft decreases stepwise over its extension through the gear box between the front and rear parts of the gear box housing, whereby a radial lip seal, that prevents the water from leaking from the water filled room and along the drilling shaft, can be arranged in the rear end portion of the drilling shaft that is of considerably smaller diameter than in the front portion of the gear box. Hence, the radial lip seal(s) that is/are arranged in this part of the drilling shaft can be relatively small, thus promoting sealing ability and life span. 钻孔机英文文献和中文翻译:http://www.youerw.com/fanyi/lunwen_56212.html